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  • Disputation: 2018-05-26 13:15 Ihresalen, Uppsala
    Cöllen, Sebastian
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Språkvetenskapliga fakulteten, Institutionen för moderna språk.
    Gefiolierte blüte kunst: Eine kognitionslinguistisch orientierte Untersuchung zur Metaphorik in Frauenlobs Marienleich2018Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    Heinrich of Meißen, also known as Frauenlob († 1318), is a central figure in Middle High German literature. As is evident from its early reception, his work was highly admired in the middle ages. In research literature, however, his ‘obscure’ poetry initially was faced with a lack of understanding.

    The main challenge for comprehending Frauenlob lies in his rich metaphorics. However, despite the importance of the metaphors in Frauenlob’s work, the question about their role in the construction of meaning was not seriously raised until the last decades and has not yet been thoroughly investigated. This problem is all the more serious as Frauenlob’s poetry, which has often been attributed with a seemingly ‘modern’ ambivalence, is at the centre of the recent debate of the historicity of metaphor. His poetry offers a fruitful empirical entry to the important issues whether metaphors are interpreted today in the same way as in the middle ages, and whether modern theories of metaphor are adequate for the historical analysis of medieval metaphorics.

    The present study aims to describe and explain how the metaphors in Frauenlob’s Marienleich functions. It is shown that the traditional substitution account of metaphor leads to a reductionist view of the construction of meaning in this text. The modern interaction account also contains aspects whose suitability with regard to the medieval expectations on the production of meaning can be questioned. As an alternative, the present investigation proposes a context sensitive analytic model based on cognitive linguistics that tries to preserve the hermeneutic difference to Frauenlob’s Marienleich. This cognitive perspective, which is here applied to Frauenlob’s work for the first time, enables a more precise description and explanation of how the metaphorical meaning is constructed than was hitherto possible. The result shows that, whereas Frauenlob’s poetry may not be as modern as is sometimes believed, the metaphors in his Marienleich are much more than an artistic show-off; rather, they represent an efficient means of actualising a complex religious meaning.

  • Disputation: 2018-05-28 13:00 Hambergsalen, Geocentrum, Uppsala
    Fälth, Billy
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Geofysik. Clay Technology AB.
    Simulating Earthquake Rupture and Near-Fault Fracture Response2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Sweden is presently a low seismicity area where most earthquakes are small and pose no serious threat to constructions. For the long-term perspectives of safety assessments of geological repositories for spent nuclear fuel, however, the effects of large earthquakes have to be considered. For the Swedish nuclear waste storage concept, seismically induced secondary fracture shear displacements across waste canister positions could pose a long-term seismic risk to the repository.

    In this thesis, I present earthquake simulations with which I study the potential for near-fault secondary fracture shear displacements. As a measure I use the Coulomb Failure Stress (CFS), but also calculate explicit fracture displacements. I account for both the dynamic and quasi-static stress perturbations generated during the earthquake. As numerical tool I use the 3DEC code, whose performance I validate using Stokes closed-form solution and the Compsyn code as benchmarks. In a model of a Mw 6.4 earthquake, I investigate how fault roughness, the fault rupture propagation model and rupture velocity may impact the near-fault CFS evolution. I find that fault roughness can reduce the amount of fault slip by tens of percent, but also increase the near-fault CFS with similar amounts locally. Furthermore, different fault rupture models generate similar CFS levels. I also find that the secondary stresses scale with rupture velocity.

    In a model based on data from the Forsmark nuclear waste repository site, and assuming stress conditions prevailing at the end of a glaciation, I simulate several high stress drop ~Mw 5.6 earthquake scenarios on the gently dipping fault zone ZFMA2 and calculate secondary fracture displacements on 300 m diameter planar fractures. Less than 1% of the fractures at the shortest distance from ZFMA2 generate displacements exceeding the 50 mm criterion established by the Swedish Nuclear Fuel and Waste Management Co. Given the high stress drops and the assumption of fracture planarity, I consider the calculated displacements to represent upper bound estimates of possible secondary displacements at Forsmark. Hence, the results should strengthen the confidence in the safety assessment of the nuclear waste repository at the Forsmark site.

    Delarbeten
    1. Simulating earthquake rupture and off-fault fracture response: Application to the safety assessment of the Swedish nuclear waste repository
    Öppna denna publikation i ny flik eller fönster >>Simulating earthquake rupture and off-fault fracture response: Application to the safety assessment of the Swedish nuclear waste repository
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    2015 (Engelska)Ingår i: Bulletin of The Seismological Society of America (BSSA), ISSN 0037-1106, E-ISSN 1943-3573, Vol. 105, nr 1, s. 134-151Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    To assess the long‐term safety of a deep repository of spent nuclear fuel, upper bound estimates of seismically induced secondary fracture shear displacements are needed. For this purpose, we analyze a model including an earthquake fault, which is surrounded by a number of smaller discontinuities representing fractures on which secondary displacements may be induced. Initial stresses are applied and a rupture is initiated at a predefined hypocenter and propagated at a specified rupture speed. During rupture we monitor shear displacements taking place on the nearby fracture planes in response to static as well as dynamic effects. As a numerical tool, we use the 3Dimensional Distinct Element Code (3DEC) because it has the capability to handle numerous discontinuities with different orientations and at different locations simultaneously. In tests performed to benchmark the capability of our method to generate and propagate seismic waves, 3DEC generates results in good agreement with results from both Stokes solution and the Compsyn code package. In a preliminary application of our method to the nuclear waste repository site at Forsmark, southern Sweden, we assume end‐glacial stress conditions and rupture on a shallow, gently dipping, highly prestressed fault with low residual strength. The rupture generates nearly complete stress drop and an Mw 5.6 event on the 12  km2 rupture area. Of the 1584 secondary fractures (150 m radius), with a wide range of orientations and locations relative to the fault, a majority move less than 5 mm. The maximum shear displacement is some tens of millimeters at 200 m fault‐fracture distance.

    Nyckelord
    earthquake rupture modelling fracure
    Nationell ämneskategori
    Geofysik
    Forskningsämne
    Geofysik med inriktning mot seismologi
    Identifikatorer
    urn:nbn:se:uu:diva-237807 (URN)10.1785/0120140090 (DOI)000348898700008 ()
    Tillgänglig från: 2014-12-05 Skapad: 2014-12-05 Senast uppdaterad: 2018-04-04Bibliografiskt granskad
    2. Simulation of co-seismic secondary fracture displacements for different earthquake rupture scenarios at the proposed nuclear waste repository site in Forsmark
    Öppna denna publikation i ny flik eller fönster >>Simulation of co-seismic secondary fracture displacements for different earthquake rupture scenarios at the proposed nuclear waste repository site in Forsmark
    2016 (Engelska)Ingår i: International Journal of Rock Mechanics And Mining Sciences, ISSN 1365-1609, E-ISSN 1873-4545, Vol. 84, s. 142-158Artikel i tidskrift (Refereegranskat) Published
    Nyckelord
    Secondary displacement; Forsmark; Nuclear waste disposal; Stress drop; Seismic efficiency
    Nationell ämneskategori
    Geofysik
    Forskningsämne
    Geofysik med inriktning mot seismologi
    Identifikatorer
    urn:nbn:se:uu:diva-283128 (URN)10.1016/j.ijrmms.2016.02.009 (DOI)000371895200015 ()
    Tillgänglig från: 2016-04-11 Skapad: 2016-04-11 Senast uppdaterad: 2018-04-10
    3. Influence of Fault Roughness on Co-Seismic Near-Fault Stress Evolution
    Öppna denna publikation i ny flik eller fönster >>Influence of Fault Roughness on Co-Seismic Near-Fault Stress Evolution
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Co-seismic displacements on fractures and faults close to large earthquakes may not contribute significantly to the shaking hazard for surface infrastructures. However, for deep geological nuclear waste repositories, such secondary displacements could, if large enough, damage intersected waste containers and constitute a significant long-term safety concern. To study how the potential for such displacements may depend on the earthquake rupture evolution, we simulate dynamic earthquake ruptures, and calculate the co-seismic evolution of Coulomb Failure Stress (CFS) on hypothetical fracture planes in the near-fault continuum. Poroelastic coupling is accounted for via Skempton’s coefficient B. We study three cases: (1) A planar fault with homogeneous properties. (2) A planar fault where the dynamic friction increases gradually along the fault edge to obtain a gentler rupture arrest. (3) An undulated fault with fractal properties. For Case 3, we consider ten different fault surface realizations. Since the undulations reduce fault slip, we also run models with adjusted dynamic friction coefficients, such that they generate seismic moments on par with that of Case 1. We observe the following: (i) The initial stress field, rather than the co-seismic stress effects, is the dominating influence on the fracture orientations that obtain the highest CFS values. (ii) Lower slip gradients and less fault slip in Case 2 reduce the maximum CFS by 10-15% relative to the reference case. (iii) Fault roughness may increase CFS locally by tens of percent. (iv) Given our reference value of B=0.5, B-value variations of ±0.5 would give CFS variations of ±20%, at most.

    Nationell ämneskategori
    Geofysik
    Identifikatorer
    urn:nbn:se:uu:diva-346811 (URN)
    Tillgänglig från: 2018-04-04 Skapad: 2018-04-04 Senast uppdaterad: 2018-04-04
    4. How does the Fault Rupture Model affect Simulated Co-Seismic Near-Fault Stress Evolution?
    Öppna denna publikation i ny flik eller fönster >>How does the Fault Rupture Model affect Simulated Co-Seismic Near-Fault Stress Evolution?
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    The dynamic and static stress perturbations generated in an earthquake affect the stability of faults and fractures in the vicinity of the rupture. Estimates of co-seismic near-fault stress effects can be made using numerical simulations. Here, we study the co-seismic stress evolution close to an earthquake using two different models to simulate the rupture. One model is the linear slip-weakening (SW) model, where a spontaneous earthquake rupture is simulated. We compare this to a constant rupture velocity time-weakening (TW) model, which we implement in four different instances of rupture velocity Vr and strength reduction time interval Δtred. We evaluate the near-fault stress effects using the Coulomb Failure Stress (CFS), which we calculate from the stress evolution at various positions relative to the rupture plane. The results show that the TW method is capable of generating similar secondary effects as those generated by the SW model. However, the assumption of constant values of Δtred and Vr implies that there will always be locations on the rupture plane where these values are incompatible. We also see that variationsin Δtred and Vr have a significant impact on the results. Particularly, Vr is important for how the stresses around the rupture front are superimposed, and is thus important for the temporal evolution and spatial distribution of CFS around the fault. Lower Vr tends to generate a gentler near-fault stress evolution and lower peak CFS values. The results also indicate that not only the momentary value of Vr is important for the secondary stress effects at a near-fault position passed by the rupture, but also the integrated Vr-history up to that position.

    Nationell ämneskategori
    Geofysik
    Forskningsämne
    Geofysik med inriktning mot seismologi
    Identifikatorer
    urn:nbn:se:uu:diva-347597 (URN)
    Tillgänglig från: 2018-04-04 Skapad: 2018-04-04 Senast uppdaterad: 2018-04-04
  • Disputation: 2018-05-28 13:15 Polhemssalen, Ångströmlaboratoriet, Uppsala
    Paulsson Do, Ulrica
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för folkhälso- och vårdvetenskap.
    Psychosocial Vulnerability Underlying Unhealthy Behaviours in Swedish Adolescents2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The overall aim was to examine the relationship between Swedish school adolescents´ health-related behaviours and psychosocial and socio-demographic factors, with the purpose of identifying vulnerability factors for unhealthy behaviours and exploring adolescents’ own experiences and thoughts about this.

    Three studies were quantitative cross-sectional studies and used data from two different questionnaires. The fourth study was a qualitative study based on focus group interviews. The sample in study I consisted of 13–18-year-old adolescents (n= 10,590) and 15–16-year-old adolescents in studies II (n=492), III (n=492) and IV (n=36). The quantitative data were analysed using a number of different statistical methods. Foremost, structural equation modelling was used in studies I and II and Poisson regression analysis in study III. Study IV used qualitative content analysis by Graneheim and Lundman.

    The results indicated that nearly 60 per cent of 15–16-year-old adolescents have at least two unhealthy behaviours. Interrelated psychosocial and socio-demographic factors constituted vulnerability for unhealthy behaviours in general in adolescents. Good psychosocial relationships were strongly related with high well-being, whereas poor social relationships and low well-being were associated with unhealthy behaviours in general. Low socio-economic group was associated with unhealthy behaviours in general but the strength of this association varied between the adolescent age groups. Encouragement from parents to adopt healthy behaviours was associated with less unhealthy behaviours. Having adolescents who cared about what their parents said regarding health-related behaviours was also associated with a lower number of unhealthy behaviours. The school and family were important social environments for adolescents´ health-related behaviours. Similarly, friends and social media were important social contexts. Fellowship, and close social relationships, in particular, was important to healthy behaviours. Fellowship with others was also stated to influence high well-being. The experience of feeling pressure was stated to be associated with low well-being and unhealthy behaviours in adolescents.

    The thesis brings new knowledge to the field of psycho-social and socio-demographic factors associated with unhealthy behaviours in Swedish adolescents. Findings may be useful in supporting adolescents to reach positive health-related behaviours.

    Delarbeten
    1. Vulnerability to unhealthy behaviours across different age groups in Swedish Adolescents: A cross-sectional study
    Öppna denna publikation i ny flik eller fönster >>Vulnerability to unhealthy behaviours across different age groups in Swedish Adolescents: A cross-sectional study
    2014 (Engelska)Ingår i: Health Psychology and Behavioral Medicine, ISSN 2164-2850, Vol. 2, nr 1, s. 296-313Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Purpose:

    There is lack of evidence on the effects of health-promoting programmes among adolescents. Health behaviour models and studies seldom compare the underlying factors of unhealthy behaviours between different adolescent age groups. The main objective of this study was to investigate factors including sociodemographic parameters that were associated with vulnerability to health-damaging behaviours and non-adoption of health-enhancing behaviours in different adolescent age groups.

    Methods:

    A survey was conducted among 10,590 pupils in the age groups of 13–14, 15–16 and 17–18 years. Structural equation modelling was performed to determine whether health-damaging behaviours (smoking and alcohol consumption) and non-adoption of health-enhancing behaviours (regular meal habits and physical activity) shared an underlying vulnerability. This method was also used to determine whether gender and socio-economic status were associated with an underlying vulnerability to unhealthy behaviours.

    Results:

    The findings gave rise to three models, which may reflect the underlying vulnerability to health-damaging behaviours and non-adoption of health-enhancing behaviours at different ages during adolescence. The four behaviours shared what was interpreted as an underlying vulnerability in the 15–16-year-old age group. In the youngest group, all behaviours except for non-participation in physical activity shared an underlying vulnerability. Similarly, alcohol consumption did not form part of the underlying vulnerability in the oldest group. Lower socio-economic status was associated with an underlying vulnerability in all the age groups; female gender was associated with vulnerability in the youngest adolescents and male gender among the oldest adolescents.

    Conclusions:

    These results suggest that intervention studies should investigate the benefits of health-promoting programmes designed to prevent health-damaging behaviours and promote health-enhancing behaviours in adolescents of different ages. Future studies should examine other factors that may contribute to the underlying vulnerability in different age groups.

    Nationell ämneskategori
    Folkhälsovetenskap, global hälsa, socialmedicin och epidemiologi Hälsovetenskaper
    Identifikatorer
    urn:nbn:se:uu:diva-226085 (URN)10.1080/21642850.2014.892429 (DOI)
    Tillgänglig från: 2014-06-11 Skapad: 2014-06-11 Senast uppdaterad: 2018-04-09Bibliografiskt granskad
    2. Psychosocial vulnerability underlying four common unhealthy behaviours in 15–16-year-old Swedish adolescents: a cross-sectional study
    Öppna denna publikation i ny flik eller fönster >>Psychosocial vulnerability underlying four common unhealthy behaviours in 15–16-year-old Swedish adolescents: a cross-sectional study
    2017 (Engelska)Ingår i: BMC Psychology, E-ISSN 2050-7283, Vol. 5, artikel-id 39Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    BACKGROUND: Factors that influence unhealthy behaviours in adolescents may have different impacts in different sociocultural settings. There is lack of research on the association between psychosocial vulnerability and unhealthy behaviours in adolescents, particularly outside the United States. The aim was to investigate both direct and indirect relationships between psychosocial conditions (subjective well-being, social relationships and self-esteem) and four health-related behaviours (smoking, alcohol consumption, meal frequency and physical activity) in Swedish adolescents aged 15-16 years. Socio-demographic variables (socio-economic status, gender and age) were also investigated.

    METHODS: To study these associations, a hypothesised model was tested using structural equation modelling. In the hypothesised model, interrelated psychosocial conditions (low well-being, poor social relationships and low self-esteem) and socio-demographic factors (low self-perceived socio-economic status, being female and higher age) together represented a vulnerability underlying smoking, alcohol consumption, irregular meal frequency and low level of physical activity. In this cross-sectional study, self-report questionnaires were used to collect data from 492 adolescents.

    RESULTS: Hypothesised pathways between psychosocial conditions, socio-demographic factors and the four unhealthy behaviours were confirmed. Low well-being was strongly associated with unhealthy behaviours, and poor social relationships showed a strong indirect association with the unhealthy behaviours. Low self-esteem, low self-perceived socio-economic status and female gender were also vulnerability factors for the unhealthy behaviours.

    CONCLUSIONS: Vulnerability for four common unhealthy behaviours was found in Swedish adolescents. This study presents the interrelationships of psychosocial and socio-demographic factors and how they were related with unhealthy behaviours. The results bring new insight into how psychosocial factors are related to unhealthy behaviours in adolescents living in northern Europe.

    Nationell ämneskategori
    Folkhälsovetenskap, global hälsa, socialmedicin och epidemiologi
    Identifikatorer
    urn:nbn:se:uu:diva-336735 (URN)10.1186/s40359-017-0209-9 (DOI)29246175 (PubMedID)
    Tillgänglig från: 2017-12-15 Skapad: 2017-12-15 Senast uppdaterad: 2018-04-08Bibliografiskt granskad
    3. Health communication with parents and teachers and unhealthy behaviours in 15- to 16-year-old Swedes
    Öppna denna publikation i ny flik eller fönster >>Health communication with parents and teachers and unhealthy behaviours in 15- to 16-year-old Swedes
    2017 (Engelska)Ingår i: Health Psychology and Behavioral Medicine, E-ISSN 2164-2850, Vol. 5, nr 1, s. 229-257Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Background: Unhealthy behaviours during adolescence constitute a major risk for numerous diseases in adulthood.

    Aim: To explore the associations between multiple unhealthy behaviours in adolescents and health behaviour information communicated by their parents and teachers, how much the adolescents cared about this information and whether adolescents went to schools with an annual health-themed week or not.

    Methods: In this cross-sectional study, a self-reported questionnaire was delivered to pupils aged 15 and 16 (n = 492). The results were analysed using Poisson regression.

    Results: The number of unhealthy behaviours was lower in adolescents whose parents encouraged them to adopt healthy behaviours. Adolescents at schools with an annual health-themed week reported more unhealthy behaviours than other adolescents. In addition, attendance at such schools did not compensate for a lack of health behaviour information communicated by parents. Caring about health behaviour information communicated by parents was associated with fewer unhealthy behaviours. In contrast, the opposite was found when adolescents cared about health information communicated by teachers.

    Conclusion: It is important for parents to encourage their adolescent children to adopt healthy behaviours because this is particularly effective at lowering the number of unhealthy behaviours in adolescents. It also appears to be important for parents and teachers to develop credibility among adolescents regarding information communicated about health issues. The results also indicate the importance of involving parents in the school health work to influence them to encourage their adolescent children to adopt healthy behaviours.

    Nationell ämneskategori
    Folkhälsovetenskap, global hälsa, socialmedicin och epidemiologi
    Identifikatorer
    urn:nbn:se:uu:diva-324318 (URN)10.1080/21642850.2017.1316666 (DOI)000424575500016 ()
    Forskningsfinansiär
    Stiftelsen Lars Hiertas Minne
    Tillgänglig från: 2017-06-14 Skapad: 2017-06-14 Senast uppdaterad: 2018-04-08Bibliografiskt granskad
    4. How 15–16-year-old Swedish adolescents experience associations of social relationships with health-related behaviours: A qualitative study
    Öppna denna publikation i ny flik eller fönster >>How 15–16-year-old Swedish adolescents experience associations of social relationships with health-related behaviours: A qualitative study
    (Engelska)Ingår i: Artikel i tidskrift (Refereegranskat) Submitted
    Nationell ämneskategori
    Folkhälsovetenskap, global hälsa, socialmedicin och epidemiologi
    Identifikatorer
    urn:nbn:se:uu:diva-347826 (URN)
    Tillgänglig från: 2018-04-08 Skapad: 2018-04-08 Senast uppdaterad: 2018-04-08
  • Disputation: 2018-05-29 10:00 Seminar Room, Belém
    Cardias Alves de Almeida, Ramon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Materialteori.
    Electronic structure and exchange interactions from ab initio theory: New perspectives and implementations2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    In this thesis, the magnetic properties of several materials were investigated using first principle calculations. The ab initio method named real space linear muffin-tin orbitals atomic sphere approximation (RS-LMTO-ASA) was used to calculate the electronic structure and magnetic properties of bulk systems, surface and nanostructures adsorbed on surfaces.

    We have implemented new features in the RS-LMTO-ASA method, such as the calculation of (a) Bloch Spectral Function (BSF), (b) orbital resolved Jij and (c) Dzyaloshinskii-Moriya interaction (DMI). Using (a), we have shown that one can calculate the dispersion relation for bulk systems using a real space method. Furthermore, the dispersion relation was revealed to be existent even for finite one-dimensional structures, such as the Mn chain on Au(111) and Ag(111) surfaces. With (b), we have investigated the orbital resolved exchange coupling parameter Jij for 3d metals. It is demonstrated that the nearest neighbor (NN) interaction for bcc Fe has intriguing behavior, however, the contribution coming from the T2g orbitals favours the anti-ferromagnetic coupling behavior. Moreover, the Fermi surface for bcc Fe is formed mostly by the T2g orbitals and these are shown to be highly Heisenberg-like, i.e. do not depend significantly on the magnetic configuration. Later, the same approach was used to study other transition metals, such as Cr, Mn, Co and Ni. In the end, we have presented the results obtained with the implementation (c). Our results have shown the large dependence of the DMI values, both the strength and direction, with respect to which magnetic configuration they are calculated from. We argue that, for the investigated systems, the non-collinearity induces currents (spin and charge) that will influence directly the DMI vectors.

    Delarbeten
    1. Magnetic and electronic structure of Mn nanostructures on Ag(111) and Au(111)
    Öppna denna publikation i ny flik eller fönster >>Magnetic and electronic structure of Mn nanostructures on Ag(111) and Au(111)
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    2016 (Engelska)Ingår i: PHYSICAL REVIEW B, ISSN 2469-9950, Vol. 93, nr 1, artikel-id 014438Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    We present results of the electronic and magnetic structure of Mn nanowires adsorbed on Ag(111) and Au(111) surfaces. For finite Mn nanowires on Ag(111) and Au(111) surfaces, our ab initio results show that the large difference between the spin-orbit splitting of these two surfaces leads to completely different magnetic configurations. The magnetic ordering for Mn nanowires adsorbed on Ag(111) is governed by the strong exchange interaction between Mn adatoms. For Mn nano-chains on Au(111), the competition between Heisenberg and Dzyaloshinskii-Moriya interactions leads to a complex magnetic structure of the clusters considered here. Among the more conspicuous results we note a spin-spiral helical type for the nanowire with seven atoms, and a complex magnetic configuration incommensurate with the substrate lattice for a double-sized Mn wire. The effect of the structural relaxation is also investigated, showing sensitivity of the exchange interactions to the bond distance to the substrate. We also demonstrate that small changes in the band filling of these Mn chains results in drastically different changes of the interatomic exchange. Finally, we show that dispersion of the electronic energy spectrum is possible even in nanostructures with bounded spatial extension.

    Nationell ämneskategori
    Den kondenserade materiens fysik
    Identifikatorer
    urn:nbn:se:uu:diva-279629 (URN)10.1103/PhysRevB.93.014438 (DOI)000369216100007 ()
    Forskningsfinansiär
    VetenskapsrådeteSSENCE - An eScience CollaborationKnut och Alice Wallenbergs Stiftelse
    Tillgänglig från: 2016-03-08 Skapad: 2016-03-02 Senast uppdaterad: 2018-04-07Bibliografiskt granskad
    2. The Bethe-Slater curve revisited; new insights from electronic structure theory
    Öppna denna publikation i ny flik eller fönster >>The Bethe-Slater curve revisited; new insights from electronic structure theory
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    2017 (Engelska)Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, artikel-id 4058Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The Bethe-Slater (BS) curve describes the relation between the exchange coupling and interatomic distance. Based on a simple argument of orbital overlaps, it successfully predicts the transition from antiferromagnetism to ferromagnetism, when traversing the 3d series. In a previous article [Phys. Rev. Lett. 116, 217202 (2016)] we reported that the dominant nearestneighbour (NN) interaction for 3d metals in the bcc structure indeed follows the BS curve, but the trends through the series showed a richer underlying physics than was initially assumed. The orbital decomposition of the inter-site exchange couplings revealed that various orbitals contribute to the exchange interactions in a highly non-trivial and sometimes competitive way. In this communication we perform a deeper analysis by comparing 3d metals in the bcc and fcc structures. We find that there is no coupling between the E-g orbitals of one atom and T-2g orbitals of its NNs, for both cubic phases. We demonstrate that these couplings are forbidden by symmetry and formulate a general rule allowing to predict when a similar situation is going to happen. In gamma-Fe, as in alpha-Fe, we find a strong competition in the symmetry-resolved orbital contributions and analyse the differences between the high-spin and low-spin solutions.

    Ort, förlag, år, upplaga, sidor
    NATURE PUBLISHING GROUP, 2017
    Nationell ämneskategori
    Fysik
    Identifikatorer
    urn:nbn:se:uu:diva-330728 (URN)10.1038/s41598-017-04427-9 (DOI)000403874900041 ()28642615 (PubMedID)
    Forskningsfinansiär
    VetenskapsrådetKnut och Alice Wallenbergs Stiftelse
    Anmärkning

    Erratum

    doi:10.1038/s41598-017-09611-5

    In the original version of this Article, Y. O. Kvashnin was incorrectly affiliated with ‘Faculdade de Fisica, Universidade Federal do Para, Belem, PA, Brazil’. The correct affiliation is listed below.

    Department of Physics and Astronomy, Division of Materials Theory, Uppsala University, Box 516, SE-75120, Uppsala, Sweden.

    This error has now been corrected in the PDF and HTML versions of the Article.

    Tillgänglig från: 2017-10-10 Skapad: 2017-10-10 Senast uppdaterad: 2018-04-07Bibliografiskt granskad
    3. Microscopic Origin of Heisenberg and Non-Heisenberg Exchange Interactions in Ferromagnetic bcc Fe
    Öppna denna publikation i ny flik eller fönster >>Microscopic Origin of Heisenberg and Non-Heisenberg Exchange Interactions in Ferromagnetic bcc Fe
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    2016 (Engelska)Ingår i: Physical Review Letters, ISSN 0031-9007, E-ISSN 1079-7114, Vol. 116, nr 21, artikel-id 217202Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    By means of first principles calculations, we investigate the nature of exchange coupling in ferromagnetic bcc Fe on a microscopic level. Analyzing the basic electronic structure reveals a drastic difference between the 3d orbitals of E-g and T-2g symmetries. The latter ones define the shape of the Fermi surface, while the former ones form weakly interacting impurity levels. We demonstrate that, as a result of this, in Fe the T-2g orbitals participate in exchange interactions, which are only weakly dependent on the configuration of the spin moments and thus can be classified as Heisenberg-like. These couplings are shown to be driven by Fermi surface nesting. In contrast, for the E-g states, the Heisenberg picture breaks down since the corresponding contribution to the exchange interactions is shown to strongly depend on the reference state they are extracted from. Our analysis of the nearest-neighbor coupling indicates that the interactions among E-g states are mainly proportional to the corresponding hopping integral and thus can be attributed to be of double-exchange origin. By making a comparison to other magnetic transition metals, we put the results of bcc Fe into context and argue that iron has a unique behavior when it comes to magnetic exchange interactions.

    Nationell ämneskategori
    Annan fysik
    Identifikatorer
    urn:nbn:se:uu:diva-298894 (URN)10.1103/PhysRevLett.116.217202 (DOI)000376628800010 ()27284671 (PubMedID)
    Forskningsfinansiär
    EU, Europeiska forskningsrådet, 338957 FEMTO/NANOVetenskapsrådeteSSENCE - An eScience CollaborationKnut och Alice Wallenbergs Stiftelse, 2012.0031 2013.0020
    Tillgänglig från: 2016-07-12 Skapad: 2016-07-12 Senast uppdaterad: 2018-04-07Bibliografiskt granskad
    4. Magnetism and ultrafast magnetization dynamics of Co and CoMn alloys at finite temperature
    Öppna denna publikation i ny flik eller fönster >>Magnetism and ultrafast magnetization dynamics of Co and CoMn alloys at finite temperature
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    2017 (Engelska)Ingår i: Physical review B, ISSN 2469-9950, Vol. 95, nr 21, artikel-id 214417Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Temperature-dependent magnetic experiments such as pump-probe measurements generated by a pulsed laser have become a crucial technique for switching the magnetization in the picosecond time scale. Apart from having practical implications on the magnetic storage technology, the research field of ultrafast magnetization poses also fundamental physical questions. To correctly describe the time evolution of the atomic magnetic moments under the influence of a temperature-dependent laser pulse, it remains crucial to know if the magnetic material under investigation has magnetic excitation spectrum that is more or less dependent on the magnetic configuration, e.g., as reflected by the temperature dependence of the exchange interactions. In this paper, we demonstrate from first-principles theory that the magnetic excitation spectra in Co in fcc, bcc, and hcp structures are nearly identical in a wide range of noncollinear magnetic configurations. This is a curious result of a balance between the size of the magnetic moments and the strength of the Heisenberg exchange interactions, that in themselves vary with configuration, but put together in an effective spin Hamiltonian results in a configuration-independent effective model. We have used such a Hamiltonian, together with ab initio calculated damping parameters, to investigate the magnon dispersion relationship as well as ultrafast magnetization dynamics of Co and Co-rich CoMn alloys.

    Nationell ämneskategori
    Den kondenserade materiens fysik
    Identifikatorer
    urn:nbn:se:uu:diva-308321 (URN)10.1103/PhysRevB.95.214417 (DOI)000404015400003 ()
    Forskningsfinansiär
    VetenskapsrådetKnut och Alice Wallenbergs Stiftelse, 2013.0020, 2012.0031StandUp
    Tillgänglig från: 2016-11-24 Skapad: 2016-11-24 Senast uppdaterad: 2018-04-07Bibliografiskt granskad
    5. Theory of noncollinear interactions beyond Heisenberg exchange: Applications to bcc Fe
    Öppna denna publikation i ny flik eller fönster >>Theory of noncollinear interactions beyond Heisenberg exchange: Applications to bcc Fe
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    2017 (Engelska)Ingår i: Physical Review B, ISSN 2469-9950, E-ISSN 2469-9969, Vol. 96, nr 14, artikel-id 144413Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    We show for a simple noncollinear configuration of the atomistic spins (in particular, where one spin is rotated by a finite angle in a ferromagnetic background) that the pairwise energy variation computed in terms of multiple-scattering formalism cannot be fully mapped onto a bilinear Heisenberg spin model even in the absence of spin-orbit coupling. The non-Heisenberg terms induced by the spin-polarized host appear in leading orders in the expansion of the infinitesimal angle variations. However, an E-g - T-2g symmetry analysis based on the orbital decomposition of the exchange parameters in bcc Fe leads to the conclusion that the nearest-neighbor exchange parameters related to the T-2g orbitals are essentially Heisenberg-like: they do not depend on the spin configuration, and can, in this case, be mapped onto a Heisenberg spin model even in extreme noncollinear cases.

    Ort, förlag, år, upplaga, sidor
    AMER PHYSICAL SOC, 2017
    Nationell ämneskategori
    Fysik
    Identifikatorer
    urn:nbn:se:uu:diva-340146 (URN)10.1103/PhysRevB.96.144413 (DOI)000412699400003 ()
    Forskningsfinansiär
    VetenskapsrådetKnut och Alice Wallenbergs Stiftelse, 2012.0031Knut och Alice Wallenbergs Stiftelse, 2013.0020EU, FP7, Sjunde ramprogrammet, 600382
    Tillgänglig från: 2018-01-26 Skapad: 2018-01-26 Senast uppdaterad: 2018-04-07Bibliografiskt granskad
    6. First-principles Dzyaloshinskii-Moryia interaction in a non-collinear framework
    Öppna denna publikation i ny flik eller fönster >>First-principles Dzyaloshinskii-Moryia interaction in a non-collinear framework
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    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Including dierent terms in the spin-Hamiltonian, we have derived an expression for theDzyaloshinskii-Moryia vector interaction (DMI) where all the three components of the vector canbe calculated independently of the magnetic conguration. Here, we have chosen the Cr triangulartrimer on Au(111) and Mn triangular trimes on Ag(111) and Au(111) surfaces to study the implementationof the derived DMI into the RS-LMTO-ASA method. Our results have shown thatthe DMI value (module and direction) is drastically dierent for collinear and non-collinear states.Based on relation between the spin and charge currents owing in the system and the non-collinearmagnetic conguration of the triangular trimer, we argued that the drastic change between the DMIcalculated considering a collinear and a non-collinear magnetic conguration can be explained bythe mechanism behind the spin and charge currents owing through the atoms when the spins arealigned in a non-collinear fashion.

    Nationell ämneskategori
    Den kondenserade materiens fysik
    Identifikatorer
    urn:nbn:se:uu:diva-347808 (URN)
    Tillgänglig från: 2018-04-07 Skapad: 2018-04-07 Senast uppdaterad: 2018-04-07
  • Disputation: 2018-05-29 10:15 Hörsal 2, Uppsala
    Andone, Irina
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Nationalekonomiska institutionen.
    Exchange Rates, Exports, Inflation, and International Monetary Cooperation2018Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    This thesis consists of three self-contained essays.

     

    Essay I: Exchange rate movements often cause anxiety among policy-makers, given the strong link between currency movements and export competitiveness, which may, in turn, affect economic growth. In this paper, I examine the strength of the effect of exchange rate movements on exports combining firm-level export data with an industry-level competitiveness index. The data span a broad sample of countries, comprising 21 advanced and 21 emerging market economies over the period 1989-2013. My findings suggest an economically and statistically significant negative effect of real appreciation on real exports. The effect is significantly larger for emerging markets as compared to advanced economies. ​Additionally, the results suggest that larger firms are particularly affected by exchange rate movements.

    Essay II: Simulations of a small open economy model à la Gali and Monacelli (2005) suggest that inflation should display similar levels, but higher volatility and higher persistence under a fixed exchange rate regime compared to a regime with a flexible exchange rate and some form of inflation targeting. I test these predictions using data for two clearly defined exchange rate regimes. One regime is the membership in the Economic and Monetary Union (EMU), which implies an irrevocably fixed exchange rate. The other is a flexible exchange rate with inflation targeting. The empirical analysis confirms the theoretical implications of the model in terms of persistence: inflation displays a higher degree of persistence in countries with a fixed exchange rate regime.

    Essay III (with Beatrice Scheubel): While the consequences and effectiveness of IMF conditionality have long constituted the focus of research, the possible negative impact of IMF conditionality on countries' willingness to start an IMF program has mainly focused on a country's own past experience. However, the recent policy debate has highlighted the existence of regional effects, unrelated to a country's own experience. In this paper, we investigate how past experience with IMF conditionality – own and peers' – affects countries' likelihood of signing an IMF arrangement again. Our results indicate strong learning from own experience, but hardly any learning from peers, except for members of the Association of Southeast Asian Nations (ASEAN). We conjecture that a negative effect associated with IMF conditionality may exist for individual country cases or specific regions, but that a more general effect cannot be related to observing how the IMF treats peers.

  • Disputation: 2018-05-29 13:15 Rosénsalen, Uppsala
    Tadesse, Amare Worku
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kvinnors och barns hälsa, Internationell mödra- och barnhälsovård (IMCH). Addis Continental Institute of Public Health, Ethiopia.
    Identification and Community Management of Severe Acute Malnutrition: Empirical evidence in rural Southern Ethiopia2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The current recommended standard management for all children with severe acute malnutrition (SAM) is Community-based Management of Acute Malnutrition (CMAM). CMAM has a community-based outpatient therapeutic program (OTP) to treat uncomplicated SAM and has been scaled-up and integrated with government health services in low-resource settings. How-ever, the context in which such large-scale programs are implemented modifies their effective-ness. This study aims at assessing factors of importance for the effectiveness of management of SAM in the community.

    A population-based survey of households with children aged under five years and a longitu-dinal study among children admitted to the integrated OTPs of rural Southern Ethiopia was undertaken. For Study I, children aged 6-59 months (n=4,297) from randomly selected house-holds were examined for differences between children identified as SAM by MUAC and WHZ. For Study II, subsets of 1,048 children admitted to OTPs were analyzed for program outcome and nutritional status at discharge (n=759) and 14 weeks after admission (n=991). For Study III, non-oedematous children (n=661) admitted to OTPs were analyzed for gains in anthropo-metric measures after 4 weeks of treatment. For Study IV, children with SAM (n=788) were studied in terms of factors of importance for their recovery. Home-visits were used to collect data and anthropometry was measured following standardized World Health Organization (WHO) techniques.

    The degree of agreement between the two anthropometric indicators of severe wasting dif-fered depending on the sex and age of the children. The indicators’ response to treatment varied according to the indicator used to define SAM at admission. While 32.7% achieved the program’s recovery criteria at discharge, 29.6% had SAM at discharge and 72.1% of children were acutely malnourished at the end of 14 weeks of follow-up. Despite low recovery rate, children of caregivers with the highest decision-making autonomy recovered faster from SAM than children of caregivers with lower autonomy.

    The poor agreement between MUAC and WHZ in diagnosing SAM within different groups of children indicates each anthropometric indicator may select different set of children for treatment. Our study provided empirical evidence that supports the current recommendation to use MUAC and WHZ independently for the management of SAM. Linking CMAM to other com-plementary programmes may improve the effectiveness of integrated large-scale nutrition programmes.

    Delarbeten
    1. Comparison of Mid-Upper Arm Circumference and Weight-for-Height to Diagnose Severe Acute Malnutrition: A Study in Southern Ethiopia
    Öppna denna publikation i ny flik eller fönster >>Comparison of Mid-Upper Arm Circumference and Weight-for-Height to Diagnose Severe Acute Malnutrition: A Study in Southern Ethiopia
    2017 (Engelska)Ingår i: Nutrients, ISSN 2072-6643, E-ISSN 2072-6643, Vol. 9, nr 3, artikel-id 267Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Weight-for-height Z-score (WHZ) and mid-upper arm circumference (MUAC) are two independent anthropometric indicators for diagnosing and admitting children with severe acute malnutrition (SAM) for treatment. While severely wasted children are at high risk of mortality, MUAC and WHZ do not always identify the same population of children as having SAM. Understanding how this discrepancy relates to age and sex may provide valuable information for care programmes for children with SAM. Age and sex distribution for differences between children identified as SAM by MUAC and WHZ were examined and the degree of agreement calculated. Children (n = 4297) aged 6-59 months with validated anthropometric measures were recruited from a population-based survey conducted in rural southern Ethiopia. MUAC < 115 mm and WHZ < 3 were used to define severe wasting as per the World Health Organization (WHO) classification. The kappa coefficient (kappa) was calculated. There was fair agreement between the MUAC and WHZ definitions of severe wasting in boys (kappa = 0.37) and children younger than 24 months (kappa = 0.32) but poor agreement in girls (kappa = 0.15) and children aged 24 months and above (kappa = 0.13). More research is needed on response to treatment and prediction of mortality using different anthropometric measurements in relation to ages and sex of children.

    Ort, förlag, år, upplaga, sidor
    MDPI AG, 2017
    Nyckelord
    MUAC, WHZ, severe acute malnutrition, agreement, age, sex and children
    Nationell ämneskategori
    Näringslära
    Identifikatorer
    urn:nbn:se:uu:diva-320872 (URN)10.3390/nu9030267 (DOI)000397023600086 ()
    Forskningsfinansiär
    Sida - Styrelsen för internationellt utvecklingssamarbete, SWE-2010-179
    Tillgänglig från: 2017-04-26 Skapad: 2017-04-26 Senast uppdaterad: 2018-04-08Bibliografiskt granskad
    2. An integrated community-based outpatient therapeutic feeding programme for severe acute malnutrition in rural Southern Ethiopia: Recovery, fatality, and nutritional status after discharge.
    Öppna denna publikation i ny flik eller fönster >>An integrated community-based outpatient therapeutic feeding programme for severe acute malnutrition in rural Southern Ethiopia: Recovery, fatality, and nutritional status after discharge.
    2017 (Engelska)Ingår i: Maternal and Child Nutrition, ISSN 1740-8695, E-ISSN 1740-8709Artikel i tidskrift (Refereegranskat) Epub ahead of print
    Abstract [en]

    A scaled up and integrated outpatient therapeutic feeding programme (OTP) brings the treatment of severely malnourished children closer to the community. This study assessed recovery from severe acute malnutrition (SAM), fatality, and acute malnutrition up to 14 weeks after admission to a programme integrated in the primary health care system. In this cohort study, 1,048 children admitted to 94 OTPs in Southern Ethiopia were followed for 14 weeks. Independent anthropometric measurements and information on treatment outcome were collected at four home visits. Only 32.7% (248/759) of children with SAM on admission fulfilled the programme recovery criteria at the time of discharge (i.e., gained 15% in weight, or oedema, if present at admission, was resolved at discharge). Of all children admitted to the programme for whom nutritional assessment was done 14 weeks later, 34.6% (321/928) were severely malnourished, and 37.5% (348/928) were moderately malnourished; thus, 72.1% were acutely malnourished. Of the children, 27/982 (2.7%) had died by 14 weeks, of whom all but one had SAM on admission. Children with severe oedema on admission had the highest fatality rate (12.0%, 9/75). The median length of admission to the programme was 6.6 weeks (interquartile range: 5.3, 8.4 weeks). Despite children participating for the recommended duration of the programme, many children with SAM were discharged still acutely malnourished and without reaching programme criteria for recovery. For better outcome of OTP, constraints in service provision by the health system as well as challenges of service utilization by the beneficiaries should be identified and addressed.

    Nyckelord
    Ethiopia, integrated outpatient therapeutic programme, outcome, recovery, severe acute child malnutrition
    Nationell ämneskategori
    Medicin och hälsovetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-331991 (URN)10.1111/mcn.12519 (DOI)29024381 (PubMedID)
    Tillgänglig från: 2017-10-20 Skapad: 2017-10-20 Senast uppdaterad: 2018-04-08
    3. Choosing Anthropometric Indicators to Monitor the Response to Treatment for Severe Acute Malnutrition in Rural Southern Ethiopia: Empirical Evidence
    Öppna denna publikation i ny flik eller fönster >>Choosing Anthropometric Indicators to Monitor the Response to Treatment for Severe Acute Malnutrition in Rural Southern Ethiopia: Empirical Evidence
    2017 (Engelska)Ingår i: Nutrients, ISSN 2072-6643, E-ISSN 2072-6643, Vol. 9, nr 12, artikel-id 1339Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The World Health Organization (WHO) recommends the assessment of nutritional recovery using the same anthropometric indicator that was used to diagnose severe acute malnutrition (SAM) in children. However, related empirical evidence from low-income countries is lacking. Non-oedematous children (n = 661) aged 6–59 months admitted to a community-based outpatient therapeutic program for SAM in rural southern Ethiopia were studied. The response to treatment in children admitted to the program based on the mid-upper arm circumference (MUAC) measurement was defined by calculating the gains in average MUAC and weight during the first four weeks of treatment. The children showed significant anthropometric changes only when assessed with the same anthropometric indicator used to define SAM at admission. Children with the lowest MUAC at admission showed a significant gain in MUAC but not weight, and children with the lowest weight-for-height/length (WHZ) showed a significant gain in weight but not MUAC. The response to treatment was largest for children with the lowest anthropometric status at admission in either measurement. MUAC and weight gain are two independent anthropometric measures that can be used to monitor sufficient recovery in children treated for SAM. This study provides empirical evidence from a low-income country to support the recent World Health Organization recommendation.

    Nationell ämneskategori
    Folkhälsovetenskap, global hälsa, socialmedicin och epidemiologi
    Identifikatorer
    urn:nbn:se:uu:diva-336874 (URN)10.3390/nu9121339 (DOI)000419188600064 ()
    Tillgänglig från: 2017-12-18 Skapad: 2017-12-18 Senast uppdaterad: 2018-04-08Bibliografiskt granskad
    4. Does caregivers’ autonomy influence recovery from Severe Acute Malnutrition in an integrated community-based outpatient Therapeutic Feeding Program?
    Öppna denna publikation i ny flik eller fönster >>Does caregivers’ autonomy influence recovery from Severe Acute Malnutrition in an integrated community-based outpatient Therapeutic Feeding Program?
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Caregivers’ autonomy is important for child nutritional status as it improves the availability of food and access to health resources necessary for children’s growth and recovery from illnesses. However, evidence on the extent of influence of caregivers’ autonomy during recovery from severe acute malnutrition (SAM) is limited. A cohort of children (n=788) aged 6-59 months admitted to community-based outpatient therapeutic programme (OTP) for SAM in rural southern Ethiopia were studied. Recovery from SAM was defined by MUAC ≥ 125 mm and absence of edema after treatment in OTP. A Kaplan Meier (KM) survival analysis was employed to estimate the recovery rates of the children treated for SAM for different level of caregivers’ autonomy and multivariable Cox proportional hazard regression analysis was used to control for confounding. Results from adjusted cox proportional hazard regression analysis indicated that children of caregivers with higher decision-making autonomy recovered more rapidly from SAM than children of caregivers with lower autonomy. Promotion of caregivers’ autonomy could augment effectiveness of a scaled up and integrated outpatient therapeutic feeding programme.

    Nyckelord
    Caregivers’ autonomy, severe acute malnutrition, outpatient therapeutic programme recovery, children
    Nationell ämneskategori
    Näringslära
    Identifikatorer
    urn:nbn:se:uu:diva-347807 (URN)
    Projekt
    COMSAM
    Forskningsfinansiär
    Sida - Styrelsen för internationellt utvecklingssamarbete
    Tillgänglig från: 2018-04-07 Skapad: 2018-04-07 Senast uppdaterad: 2018-04-08
  • Disputation: 2018-05-30 09:00 ITC/2446, Uppsala
    Zhu, Yunyun
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Datorteknik. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för datorteknik.
    Caches, Transactions and Memories: Models, Coherence and Consistency2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Computers have brought us inestimable convenience in recent years. We have become dependent on them and more sensitive to their performance. During the past decades, we have been trying to improve program efficiency. The invention of multi-core systems is regarded as the new era of boosting performance of computer programs. When we focus on improving program efficiency, we also need to pay attention to program correctness. In some specific areas, errors, aka bugs, of programs can cause disastrous consequences. The dominant approach to bug detection is testing, which is conducted by executing a program against test cases generated based on scenarios. A bug is found when the output of the program does not match the expected output defined in the test case. One main drawback of testing is that it only shows the presence of bugs. An alternative approach is formal verification, which is a method that can exhaustively analyze the program executions and therefore show the absence of bugs. This thesis focuses on one of the main areas of formal verification - model checking. Model checking analyzes a mathematical model extracted from a program and automatically checks if it satisfies the desired properties.

    In this thesis, we first consider verifying safety and liveness properties for transactional memories. In particular, we consider the FlexTM hybrid transactional memory. We build a formal model of FlexTM, and apply a small model theorem that restricts the number of threads and variables in the model. This allows us to reduce the problem of verifying safety and liveness properties of FlexTM to checking language inclusion between the automata of FlexTM and a reference transactional memory. Second, we present a method for automatic verification of cache coherence protocols in the presence of transactional memories. We build a formal model containing a filter that represents the conflict resolution strategies of the transactional memory. We also apply a small model theorem which limits the number of cache lines of the protocol. To check cache coherence, we extend a backward reachability algorithm for infinite state systems, by removing the traces not allowed by the filter. Using this technique, we verify two cache protocols under different transactional memories respectively and conclude that they both maintain coherence.  Finally, we consider verification of safety properties of programs running over Self-Invalidate and Self-Downgrade cache coherence protocols. To that end, we define a formal model which captures the weak memory model induced by such protocols. We design an algorithm for inserting a set of optimal fences in the program, which guarantees the safety property while still maintaining the efficiency of a maximal degree.

    Delarbeten
    1. Verifying safety and liveness for the FlexTM hybrid transactional memory
    Öppna denna publikation i ny flik eller fönster >>Verifying safety and liveness for the FlexTM hybrid transactional memory
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    2013 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    We consider the verification of safety (strict serializability and abort consistency) and liveness obstruction and livelock freedom) for the hybrid transactional memory framework FlexTM. This framework allows for flexible implementations of transactional memories based on an adaptation of the MESI coherence protocol. FlexTM allows for both eager and lazy conflict resolution strategies. Like in the case of Software Transactional Memories, the verification problem is not trivial as the number of concurrent transactions, their size, and the number of accessed shared variables cannot be a priori bounded. This complexity is exacerbated by aspects that are specific to hardware and hybrid transactional memories. Our work takes into account intricate behaviours such as cache line based conflict detection, false sharing, invisible reads or non-transactional instructions. We carry out the first automatic verification of a hybrid transactional memory and establish, by adopting a small model approach, challenging properties such as strict serializability, abort consistency, and obstruction freedom for both an eager and a lazy conflict resolution strategies. We also detect an example that refutes livelock freedom. To achieve this, our prototype tool makes use of the latest antichain based techniques to handle systems with tens of thousands of states.

    Ort, förlag, år, upplaga, sidor
    Grenoble, France: , 2013
    Nationell ämneskategori
    Datorsystem
    Identifikatorer
    urn:nbn:se:uu:diva-213232 (URN)978-1-4503-2153-2 (ISBN)
    Konferens
    Design, Automation and Test in Europe, DATE 13, Grenoble, France, March 18-22, 2013
    Projekt
    UPMARC
    Tillgänglig från: 2013-12-19 Skapad: 2013-12-19 Senast uppdaterad: 2018-04-09
    2. Verification of Cache Coherence Protocols wrt. Trace Filters
    Öppna denna publikation i ny flik eller fönster >>Verification of Cache Coherence Protocols wrt. Trace Filters
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    2015 (Engelska)Ingår i: Proc. 15th Conference on Formal Methods in Computer-Aided Design, Piscataway, NJ: IEEE , 2015, s. 9-16Konferensbidrag, Publicerat paper (Refereegranskat)
    Ort, förlag, år, upplaga, sidor
    Piscataway, NJ: IEEE, 2015
    Nationell ämneskategori
    Datavetenskap (datalogi)
    Identifikatorer
    urn:nbn:se:uu:diva-272322 (URN)978-0-9835678-5-1 (ISBN)
    Konferens
    FMCAD 2015, September 27–30, Austin, TX
    Projekt
    UPMARC
    Tillgänglig från: 2015-09-30 Skapad: 2016-01-13 Senast uppdaterad: 2018-04-09
    3. Fencing programs with self-invalidation and self-downgrade
    Öppna denna publikation i ny flik eller fönster >>Fencing programs with self-invalidation and self-downgrade
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    2016 (Engelska)Ingår i: Formal Techniques for Distributed Objects, Components, and Systems, Springer, 2016, s. 19-35Konferensbidrag, Publicerat paper (Refereegranskat)
    Ort, förlag, år, upplaga, sidor
    Springer, 2016
    Serie
    Lecture Notes in Computer Science, ISSN 0302-9743 ; 9688
    Nationell ämneskategori
    Datorteknik
    Identifikatorer
    urn:nbn:se:uu:diva-300663 (URN)10.1007/978-3-319-39570-8_2 (DOI)000379297600002 ()978-3-319-39569-2 (ISBN)
    Konferens
    FORTE 2016, June 6–9, Heraklion, Greece
    Projekt
    UPMARC
    Tillgänglig från: 2016-05-24 Skapad: 2016-08-10 Senast uppdaterad: 2018-04-09Bibliografiskt granskad
    4. Mending fences with self-invalidation and self-downgrade
    Öppna denna publikation i ny flik eller fönster >>Mending fences with self-invalidation and self-downgrade
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    2018 (Engelska)Ingår i: Logical Methods in Computer Science, ISSN 1860-5974, E-ISSN 1860-5974, Vol. 14, nr 1, artikel-id 6Artikel i tidskrift (Refereegranskat) Published
    Nationell ämneskategori
    Datavetenskap (datalogi)
    Identifikatorer
    urn:nbn:se:uu:diva-347675 (URN)000426512000004 ()
    Tillgänglig från: 2018-01-16 Skapad: 2018-04-06 Senast uppdaterad: 2018-05-17Bibliografiskt granskad
  • Disputation: 2018-05-30 09:00 Häggsalen, Uppsala
    Wani, Ishtiaq Hassan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Fabrication, functionalization and electrical conductance modulation of nanoparticle based molecular electronic Nano-devices2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Over the years many techniques have been proposed for the purpose of the formation of electrically conducting metal-molecule-metal junctions. One such technique utilizes gold-nanoparticles (AuNPs) that could assist in contacting small molecules between large gaps. The Ideal device structure then comprises of one nanoparticle and two molecules that are aligned as electrode1-molecule-AuNP-molecule-electrode2.

    In present work these AuNP-molecule hybrids were fabricated inside sub 20 nm sized nanogaps between nanoelectrodes. The nanogaps were fabricated by milling of thin gold wires using focused ion beam. The tuning of the ion dosage resulted in the tuning of the gap size and the smallest nanogap of 2.3 nm was achieved.

    The nano molecular electronic device (nanoMoED) platform comprised of the AuNPs that were assembled inside the nanogaps via dielectrophoresis. Two types of the AuNPs were used that were different from each other due to their functionalization chemistry. The low bias resistance 'RLB' of the nanoMoED platform was (i) reduced as compared to the nanogaps (ii) remained stable in toluene and air, and (iii) was reduced when exposed to the electron beam.

    The nanoMoED platform was functionalized with various molecules using the molecular place exchange method. The successful functionalization resulted in the reduction of the 'RLB'. The smallest value of the 'RLBof the nanoMoED devices was achieved when the inserted molecule was not only highly conducting but also its length was same as the initial spacing between the AuNPs.

    The nitrogen dioxide (NO2) molecules reduced the 'RLBof the nanoMoED devices that were made with 4,4'-biphenyl dithiol. The theoretical simulations showed that this reduction was due to the induced states at Fermi energy of the junction. The nanoMoED devices made with 1,8-octanedithiol showed conductance switching between two levels because of different geometries of the Au-S contact. This switching vanished when these devices were exposed to NO2 and a strong enhancement of signal to noise ratio was observed.

    On the basis of these results this thesis suggests possible routes for the fabrication of highly conducting nanoMoED devices as well as elucidates the possibility of using the nanoMoED devices for gas sensing applications.

    Delarbeten
    1. Fabrication of reproducible sub-5 nm nanogaps by a focused ion beam and observation of Fowler-Nordheim tunneling
    Öppna denna publikation i ny flik eller fönster >>Fabrication of reproducible sub-5 nm nanogaps by a focused ion beam and observation of Fowler-Nordheim tunneling
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    2015 (Engelska)Ingår i: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 107, nr 10, artikel-id 103108Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Creating a stable high resistance sub-5 nm nanogap in between conductive electrodes is one of the major challenges in the device fabrication of nano-objects. Gap-sizes of 20 nm and above can be fabricated reproducibly by the precise focusing of the ion beam and careful milling of the metallic lines. Here, by tuning ion dosages starting from 4.6 x 10(10) ions/cm and above, reproducible nanogaps with sub-5 nm sizes are milled with focused ion beam. The resistance as a function of gap dimension shows an exponential behavior, and Fowler-Nordheim tunneling effect was observed in nanoelectrodes with sub-5 nm nanogaps. The application of Simmon's model to the milled nanogaps and the electrical analysis indicates that the minimum nanogap size approaches to 2.3 nm.

    Nationell ämneskategori
    Fysik Annan teknik
    Identifikatorer
    urn:nbn:se:uu:diva-264851 (URN)10.1063/1.4930821 (DOI)000361640200043 ()
    Tillgänglig från: 2015-10-19 Skapad: 2015-10-19 Senast uppdaterad: 2018-04-12Bibliografiskt granskad
    2. Designing sterically demanding thiolate coated AuNPs for electrical characterization of BPDT in a NP-molecule-nanoelectrode platform
    Öppna denna publikation i ny flik eller fönster >>Designing sterically demanding thiolate coated AuNPs for electrical characterization of BPDT in a NP-molecule-nanoelectrode platform
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    2017 (Engelska)Ingår i: MOLECULAR SYSTEMS DESIGN & ENGINEERING, ISSN 2058-9689, Vol. 2, nr 2, s. 133-139Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Molecular electronics with single or few molecules requires a stable metal-molecule nanojunction platform. Herein, we report the design and synthesis of gold nanoparticles coated with sterically demanding thiol ligands that are essential to fabricate a versatile and stable nanoelectrode-molecule-nanoparticle platform suitable for electrical characterization of small organic molecules. By combining.-tetraphenylmethane ether functionalized alkyl thioacetate and alkyl thiols, we prepared highly stable gold nanoparticles in a one-phase reaction providing simple and efficient purification. This robust preparation gives highly pure nanoparticles in very high yields (up to 90%) with long-time shelf stability. The synthesis in this work has superior reproducibility compared to previous synthesis processes that are currently being used for such molecular electronics platforms. Electron microscopy confirms the formation of uniform and small nanoparticles in the range of 5 to 7 nm. These nanoparticles with different ligand surface coverages were placed in a 20 nm nanoelectrode setup using dielectrophoretic forces. This setup was utilized to characterize the conductivity of the molecular wire 4,4'-biphenyldithiol introduced via ligand placeexchange under ambient conditions.

    Ort, förlag, år, upplaga, sidor
    ROYAL SOC CHEMISTRY, 2017
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-323512 (URN)10.1039/c6me00095a (DOI)000400987200003 ()
    Tillgänglig från: 2017-06-14 Skapad: 2017-06-14 Senast uppdaterad: 2018-04-12Bibliografiskt granskad
    3. Investigation of the factors that affect the fabrication of highly conducting NP-molecule junctions inside sub 20 nm molecular electronic devices.
    Öppna denna publikation i ny flik eller fönster >>Investigation of the factors that affect the fabrication of highly conducting NP-molecule junctions inside sub 20 nm molecular electronic devices.
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    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-348337 (URN)
    Tillgänglig från: 2018-04-11 Skapad: 2018-04-11 Senast uppdaterad: 2018-04-12
    4. Sub 20 nm metal-conjugated molecule junctions acting as a nitrogen dioxide sensor
    Öppna denna publikation i ny flik eller fönster >>Sub 20 nm metal-conjugated molecule junctions acting as a nitrogen dioxide sensor
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    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-348341 (URN)
    Tillgänglig från: 2018-04-11 Skapad: 2018-04-11 Senast uppdaterad: 2018-04-12
    5. Change of random telegraph conductance signal in different gas atmospheres in a nano molecular electronic device
    Öppna denna publikation i ny flik eller fönster >>Change of random telegraph conductance signal in different gas atmospheres in a nano molecular electronic device
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    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-348338 (URN)
    Tillgänglig från: 2018-04-11 Skapad: 2018-04-11 Senast uppdaterad: 2018-04-12
  • Disputation: 2018-05-30 10:15 Universitetshuset, lärosal IX, Uppsala
    Bergman, Jon
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Juridiska fakulteten, Juridiska institutionen.
    Concentrations in the EU pharmaceutical sector: The protection of effective competition under Council Regulation No 139/2004 on the control of concentrations between undertakings2018Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [sv]

    En central del av konkurrensrätten utgörs av kontrollen av företagskoncentrationer, dvs. de förändringar i konkurrensstrukturen som följer av fusioner och företagsförvärv. Genom att kontrollera koncentrationer med en Unionsdimension övervakar Europeiska kommissionen att förekomsten av effektiv konkurrens inte påtagligt försämras inom EU:s inre marknad, särskilt genom att förhindra att fusionerande företag får eller förstärker en dominerande ställning. Inom EU utgörs den centrala lagstiftningen av Rådets förordning (EG) nr 139/2004 av den 20 januari 2004 om kontroll av företagskoncentrationer. Med stöd av förordningen har kommissionen möjlighet att som en yttersta sanktion förbjuda koncentrationer helt eller delvis. I avhandlingen studeras kommissionens tillämpning av förordningen beträffande företagskoncentrationer inom läkemedelsindustrin. Läkemedelsindustrin företer många särdrag i jämförelse med andra ekonomiska sektorer. Inte minst beträffande förekomsten av extensiv sektor-specifik reglering av utveckling, tillverkning och försäljning av läkemedelsprodukter.

    Studien lyfter fram flera aspekter där kontrollen av företagskoncentrationer påverkas av de speciella förutsättningarna för effektiv konkurrens som karakteriserar marknaden för läkemedel. Utöver att ge en ingående beskrivning över de närmare skälen som motiverar varför företagskoncentrationer bör kontrolleras, koncentrationsförordningens närmare innehåll samt de grundläggande regelverken som syftar till att skydda effektiv konkurrens inom läkemedelssektorn, studeras definitionen av den relevanta marknaden för läkemedelsprodukter, hur konkurrenstestet i koncentrationsförordningen tolkas och tillämpas samt vilka typer av korrigerande åtgärder som kan aktualiseras när ett eller flera läkemedelsföretag fusioneras eller förvärvas.

  • Disputation: 2018-05-30 13:00 Sal IX, Uppsala
    Ternström, Elin
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kvinnors och barns hälsa.
    Identification and Treatment of Women with a Fear of Birth2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Although a fear of birth affects many women during pregnancy and is associated with adverse birth outcomes, it is rarely measured in clinical practice and evidence-based treatments are lacking. The aim of this thesis was to assess the clinical utility of the Fear of Birth Scale, and to evaluate the effect of guided Internet-based cognitive behavior therapy compared with standard care on the levels of fear of birth in pregnant and postpartum women.

    This thesis consists of four papers originating from three studies. The Fear of Birth Scale was used to measure fear of birth among pregnant women in all three studies. In Study I, prevalence of fear of birth among Swedish-born and foreign-born pregnant women was measured, and in Study II, 31 pregnant women were interviewed about their thoughts when assessing fear of birth. In Study III, a multicenter randomized controlled trial was conducted to compare guided Internet-based cognitive behavior therapy (ICBT) with standard care for pregnant women with a fear of birth.

    Fear of birth was identified among 22% of the pregnant women. Prevalence was twice as high among the foreign-born women (37%) compared to the Swedish-born women (18%). When asking the participants what they thought when assessing their fear on the Fear of Birth Scale, they confirmed that they had understood the measurement intent of the scale. The randomized controlled trial showed that fear of birth decreased during pregnancy and postpartum in both groups. However, the levels of fear decreased more in the guided ICBT-group when measuring fear of birth up to one year postpartum. The changes in fear of birth over time did not differ between parity groups.

    Altogether, these results suggest that the Fear of Birth Scale is a suitable screening instrument for identifying pregnant women with a fear of birth in a clinical setting and that such screening would be beneficial, as it probably would increase the chance of achieving a more equitable care. As the effect of time during pregnancy and postpartum was most evident in reducing fear of birth, this can be communicated to pregnant women, along with a continuous dialogue about how the women experience fear during pregnancy.

    Delarbeten
    1. Higher prevalence of childbirth related fear in foreign born pregnant women: Findings from a community sample in Sweden
    Öppna denna publikation i ny flik eller fönster >>Higher prevalence of childbirth related fear in foreign born pregnant women: Findings from a community sample in Sweden
    2015 (Engelska)Ingår i: Midwifery, ISSN 0266-6138, E-ISSN 1532-3099, Vol. 31, nr 4, s. 445-450Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    OBJECTIVE:

    to investigate the prevalence of childbirth related fear (CBRF) in early pregnancy among both Swedish born and foreign born women living in Sweden.

    DESIGN:

    a cross sectional prevalence study. Data was collected by a questionnaire, which was available in Swedish and eight other languages.

    SETTING:

    a university hospital in the middle of Sweden.

    PARTICIPANTS:

    the recruitment took place during a two month period where the participating women completed the Fear of Birth Scale (FOBS) in mid-pregnancy.

    MEASUREMENTS:

    prevalence of CBRF, the cut-point of 60 and above. Odds ratios with a 95% confidence interval were calculated between women born in Sweden and women born in a foreign country. Stratified analyses were also performed separately for Swedish born and foreign born women.

    FINDINGS:

    in total 606 women completed the survey, 78% were born in Sweden and 22% were born in a foreign country. About 22% of the total sample scored 60 or more on the FOBS-scale. Almost 18% (n=85) of the women born in Sweden reported CBRF whereas 37 % (n=49) of the foreign born women reported CBRF. Being born outside Sweden (OR 2.7; CI 1.7-4.0) and expecting the first baby (OR 1.9; CI 1.3-2.8) were associated with CBRF. There were no differences in age, civil status or level of education between women with or without FOBS≥60. However, a stratified analysis showed that primiparas born in a foreign country (OR 3.8; CI 1.8-8.0) were more likely to score 60 or more on the FOBS-scale compared to multiparas born in a foreign country.

    KEY CONCLUSIONS:

    childbirth related fear was almost three times as common among foreign born women when compared to Swedish women. Foreign born childbearing women are an extremely vulnerable group who need culturally sensitive and targeted support from caregivers. Further research is needed to clearly identify the components of women׳s childbirth related fear in various ethnic groups.

    Nationell ämneskategori
    Reproduktionsmedicin och gynekologi
    Identifikatorer
    urn:nbn:se:uu:diva-239490 (URN)10.1016/j.midw.2014.11.011 (DOI)000353526100007 ()25529841 (PubMedID)
    Tillgänglig från: 2014-12-28 Skapad: 2014-12-28 Senast uppdaterad: 2018-04-09Bibliografiskt granskad
    2. Pregnant women's thoughts when assessing fear of birth on the Fear of Birth Scale
    Öppna denna publikation i ny flik eller fönster >>Pregnant women's thoughts when assessing fear of birth on the Fear of Birth Scale
    2016 (Engelska)Ingår i: Women and Birth, ISSN 1871-5192, E-ISSN 1878-1799, Vol. 29, nr 3, s. E44-E49Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    BACKGROUND:

    Fear of childbirth is common during pregnancy but rarely assessed in clinical practice. The Fear of Birth Scale has been proposed as a valid measure suitable for assessing fear of birth in an antenatal clinical context. To make sure that the scale makes sense in relation to the known constructs of fear of birth, it is important to find out what women think when responding to the Fear of Birth Scale.

    AIM:

    To report what women in mid-pregnancy think when assessing fear of birth on the Fear of Birth Scale.

    METHODS:

    A qualitative design using semi-structured interviews with a think aloud technique was used. Thirty-one women were recruited in gestational week 17-20. Content analysis was conducted to describe the different dimensions of fear of birth.

    FINDINGS:

    Worry was described as unspecific feelings and thoughts, often with a negative loading. Fear was described as a strong feeling connected to something specific. Furthermore, the women thought about aspects that influence their worries and fears and explained the strategies that helped them to cope with their fear of birth.

    CONCLUSION:

    Women could clearly assess, describe, and discuss fear of birth using the Fear of Birth Scale. This supports the use of the Fear of Birth Scale in clinical settings as a starting point for further dialogue about women's fear of birth. The dialogue may identify women's need for information, treatment, and referral when necessary.

    Nyckelord
    Fear of birth; Fear of Birth Scale (FOBS); Think aloud; Worry; Pregnancy
    Nationell ämneskategori
    Reproduktionsmedicin och gynekologi
    Identifikatorer
    urn:nbn:se:uu:diva-270892 (URN)10.1016/j.wombi.2015.11.009 (DOI)000377990700002 ()26710973 (PubMedID)
    Tillgänglig från: 2016-01-04 Skapad: 2016-01-04 Senast uppdaterad: 2018-04-09Bibliografiskt granskad
    3. A randomized controlled study comparing internet-based cognitive behavioral therapy and counselling by standard care for fear of birth: A study protocol
    Öppna denna publikation i ny flik eller fönster >>A randomized controlled study comparing internet-based cognitive behavioral therapy and counselling by standard care for fear of birth: A study protocol
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    2017 (Engelska)Ingår i: Sexual & Reproductive HealthCare, ISSN 1877-5756, E-ISSN 1877-5764, Vol. 13, s. 75-82Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Fear of birth is a concern that requires evidence based treatment. The aim of this study is to present the protocol of a randomized controlled multi-center trial to compare internet-based cognitive therapy with counseling as standard care for pregnant women reporting fear of birth. Participants will be recruited in mid-pregnancy. Women who score 60 or above on the Fear of Birth Scale will be offered to participate in this study. Data will be collected by questionnaires including validated instruments at baseline and follow-ups at gestational weeks 30 and 36, two months and one year after birth. The primary outcome will be level of fear of birth measured with the Fear of Birth Scale at 36 weeks of gestation. Secondary outcome measures are level of fear of birth at two months and one year after giving birth, preferences for mode of birth, requests for elective cesarean section, compliance and satisfaction with treatment and birth outcomes. A power calculation based on a 20% reduction of fear implies that approximately 200 will be included in the trial. The study outlined in this protocol will be the first randomized controlled trial comparing internet-based cognitive therapy with counseling for women reporting fear of birth. An effective treatment may result in better overall health for women with fear of birth and a reduction in cesarean sections for non-medical reasons. Evidence regarding treatment options of fear of birth will also provide a greater choice for women.

    Ort, förlag, år, upplaga, sidor
    Elsevier, 2017
    Nationell ämneskategori
    Folkhälsovetenskap, global hälsa, socialmedicin och epidemiologi
    Identifikatorer
    urn:nbn:se:uu:diva-332598 (URN)10.1016/j.srhc.2017.06.001 (DOI)000411305800011 ()28844361 (PubMedID)
    Tillgänglig från: 2017-10-31 Skapad: 2017-10-31 Senast uppdaterad: 2018-04-09Bibliografiskt granskad
    4. A randomized controlled trial comparing Internet-based cognitive behavior therapy with standard care for women with fear of birth
    Öppna denna publikation i ny flik eller fönster >>A randomized controlled trial comparing Internet-based cognitive behavior therapy with standard care for women with fear of birth
    Visa övriga...
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Nationell ämneskategori
    Reproduktionsmedicin och gynekologi
    Identifikatorer
    urn:nbn:se:uu:diva-347568 (URN)
    Tillgänglig från: 2018-04-04 Skapad: 2018-04-04 Senast uppdaterad: 2018-04-09
  • Disputation: 2018-05-30 13:15 Häggsalen, Ångströmslaboratoriet, Uppsala
    Liljegren, Sofie
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Teoretisk astrofysik.
    Stellar Winds of Cool Giants: Investigating the Mass-Loss Mechanism of AGB Stars2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Asymptotic giant branch (AGB) stars are luminous cool giants of low to intermediate mass that are strongly pulsating and non-spherical, with heavy mass loss through a stellar wind. The mass loss makes these stars important for galactic chemistry, as the wind enriches the interstellar medium with new elements and dust, and it determines the final fate of these stars.

    The winds of AGB stars are believed to be driven by a combination of pulsation-induced shocks and radiation pressure on dust grains, which form in the atmospheres. The two processes, pulsation and mass loss, are usually simulated using different computational codes, as the physical environment of the atmosphere, where the wind is driven, is vastly different from the interior, where the pulsations originate. In this work we try to bridge this gap.

    The dynamical atmosphere and wind code DARWIN is used to study dust driven winds. An extensive grid of DARWIN models is constructed to investigate how the mass-loss rates depend on different stellar parameters. The models reproduce observed dynamical properties and we find a strong correlation between mass-loss rates and luminosities.

    The simplified description of stellar pulsation in standard DARWIN models, however, introduces free parameters that need to be constrained. The atmosphere models are highly non-linear and even moderate changes to the pulsation properties may have significant impact on the mass-loss rate and wind velocity.

    To self-consistently model the pulsation process, and to study atmospheric structures caused by the convection, the radiation hydrodynamical code CO5BOLD is used to produce an exploratory grid of 3D star-in-a-box models. The resulting models have realistic radii and periods, and give important insights into the complex non-spherical structure of AGB stars. Pulsation properties are derived from the CO5BOLD models and used as input in the DARWIN models. Average wind properties from models with CO5BOLD input agree with the standard DARWIN models, however the winds show large density variations with time, which may affect comparisons with observations.

    Delarbeten
    1. Dust-driven winds of AGB stars: The critical interplay of atmospheric shocks and luminosity variations
    Öppna denna publikation i ny flik eller fönster >>Dust-driven winds of AGB stars: The critical interplay of atmospheric shocks and luminosity variations
    2016 (Engelska)Ingår i: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 589, artikel-id A130Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Context. Winds of AGB stars are thought to be driven by a combination of pulsation-induced shock waves and radiation pressure on dust. In dynamic atmosphere and wind models, the stellar pulsation is often simulated by prescribing a simple sinusoidal variation in velocity and luminosity at the inner boundary of the model atmosphere.

    Aims. We experiment with different forms of the luminosity variation in order to assess the effects on the wind velocity and mass-loss rate, when progressing from the simple sinusoidal recipe towards more realistic descriptions. This will also give an indication of how robust the wind properties derived from the dynamic atmosphere models are.

    Methods. Using state-of-the-art dynamical models of C-rich AGB stars, a range of different asymmetric shapes of the luminosity variation and a range of phase shifts of the luminosity variation relative to the radial variation are tested. These tests are performed on two stellar atmosphere models. The first model has dust condensation and, as a consequence, a stellar wind is triggered, while the second model lacks both dust and wind.

    Results. The first model with dust and stellar wind is very sensitive to moderate changes in the luminosity variation. There is a complex relationship between the luminosity minimum, and dust condensation: changing the phase corresponding to minimum luminosity can either increase or decrease mass-loss rate and wind velocity. The luminosity maximum dominates the radiative pressure on the dust, which in turn, is important for driving the wind. An earlier occurrence of the maximum, with respect to the propagation of the pulsation-induced shock wave, then increases the wind velocity, while a later occurrence leads to a decrease. These effects of changed luminosity variation are coupled with the dust formation. In contrast there is very little change to the structure of the model without dust.

    Conclusions. Changing the luminosity variation, both by introducing a phase shift and by modifying the shape, influences wind velocity and the mass-loss rate. To improve wind models it would probably be desirable to extract boundary conditions from 3D dynamical interior models or stellar pulsation models.

    Nyckelord
    stars: late-type, stars: AGB and post-AGB, stars: atmospheres, stars: winds, outflows, infrared: stars, line: profiles
    Nationell ämneskategori
    Astronomi, astrofysik och kosmologi
    Identifikatorer
    urn:nbn:se:uu:diva-298682 (URN)10.1051/0004-6361/201527885 (DOI)000375318300142 ()
    Forskningsfinansiär
    Vetenskapsrådet
    Tillgänglig från: 2016-07-07 Skapad: 2016-07-06 Senast uppdaterad: 2018-04-10Bibliografiskt granskad
    2. Pulsation-induced atmospheric dynamics in M-type AGB stars: Effects on wind properties, photometric variations and near-IR CO line profiles
    Öppna denna publikation i ny flik eller fönster >>Pulsation-induced atmospheric dynamics in M-type AGB stars: Effects on wind properties, photometric variations and near-IR CO line profiles
    2017 (Engelska)Ingår i: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 606, artikel-id A6Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Context. Wind-driving in asymptotic giant branch (AGB) stars is commonly attributed to a two-step process. First, matter in the stellar atmosphere is levitated by shock waves, induced by stellar pulsation, and second, this matter is accelerated by radiation pressure on dust, resulting in a wind. In dynamical atmosphere and wind models the effects of the stellar pulsation are often simulated by a simplistic prescription at the inner boundary.

    Aims. We test a sample of dynamical models for M-type AGB stars, for which we kept the stellar parameters fixed to values characteristic of a typical Mira variable but varied the inner boundary condition. The aim was to evaluate the effect on the resulting atmosphere structure and wind properties. The results of the models are compared to observed mass-loss rates and wind velocities, photometry, and radial velocity curves, and to results from 1D radial pulsation models. The goal is to find boundary conditions which give realistic atmosphere and wind properties.

    Methods. Dynamical atmosphere models are calculated, using the DARWIN code for different combinations of photospheric velocities and luminosity variations. The inner boundary is changed by introducing an offset between maximum expansion of the stellar surface and the luminosity and/or by using an asymmetric shape for the luminosity variation. Ninety-nine different combinations of theses two changes are tested.

    Results. The model atmospheres are very sensitive to the inner boundary. Models that resulted in realistic wind velocities and mass-loss rates, when compared to observations, also produced realistic photometric variations. For the models to also reproduce the characteristic radial velocity curve present in Mira stars (derived from CO Delta v = 3 lines), an overall phase shift of 0.2 between the maxima of the luminosity and radial variation had to be introduced. This is a larger phase shift than is found by 1D radial pulsation models.

    Conclusions. We find that a group of models with different boundary conditions (29 models, including the model with standard boundary conditions) results in realistic velocities and mass-loss rates, and in photometric variations. To achieve the correct line splitting time variation a phase shift is needed.

    Nyckelord
    stars: AGB and post-AGB, stars: atmospheres, stars: winds, outflows, infrared: stars, line: profiles
    Nationell ämneskategori
    Astronomi, astrofysik och kosmologi
    Identifikatorer
    urn:nbn:se:uu:diva-337752 (URN)10.1051/0004-6361/201731137 (DOI)000412873800006 ()
    Forskningsfinansiär
    Vetenskapsrådet
    Tillgänglig från: 2018-01-12 Skapad: 2018-01-12 Senast uppdaterad: 2018-04-10Bibliografiskt granskad
    3. Global 3D radiation-hydrodynamics models of AGB stars: Effects of convection and radial pulsations on atmospheric structures
    Öppna denna publikation i ny flik eller fönster >>Global 3D radiation-hydrodynamics models of AGB stars: Effects of convection and radial pulsations on atmospheric structures
    2017 (Engelska)Ingår i: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746, Vol. 600, artikel-id A137Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Context. Observations of asymptotic giant branch (AGB) stars with increasing spatial resolution reveal new layers of complexity of atmospheric processes on a variety of scales.

    Aims. To analyze the physical mechanisms that cause asymmetries and surface structures in observed images, we use detailed 3D dynamical simulations of AGB stars; these simulations self-consistently describe convection and pulsations.

    Methods. We used the CO5BOLD radiation-hydrodynamics code to produce an exploratory grid of global "star-in-a-box" models of the outer convective envelope and the inner atmosphere of AGB stars to study convection, pulsations, and shock waves and their dependence on stellar and numerical parameters.

    Results. The model dynamics are governed by the interaction of long-lasting giant convection cells, short-lived surface granules, and strong, radial, fundamental-mode pulsations. Radial pulsations and shorter wavelength, traveling, acoustic waves induce shocks on various scales in the atmosphere. Convection, waves, and shocks all contribute to the dynamical pressure and, thus, to an increase of the stellar radius and to a levitation of material into layers where dust can form. Consequently, the resulting relation of pulsation period and stellar radius is shifted toward larger radii compared to that of non-linear 1D models. The dependence of pulsation period on luminosity agrees well with observed relations. The interaction of the pulsation mode with the non-stationary convective flow causes occasional amplitude changes and phase shifts. The regularity of the pulsations decreases with decreasing gravity as the relative size of convection cells increases. The model stars do not have a well-defined surface. Instead, the light is emitted from a very extended inhomogeneous atmosphere with a complex dynamic pattern of high-contrast features.

    Conclusions. Our models self-consistently describe convection, convectively generated acoustic noise, fundamental-mode radial pulsations, and atmospheric shocks of various scales, which give rise to complex changing structures in the atmospheres of AGB stars.

    Ort, förlag, år, upplaga, sidor
    EDP SCIENCES S A, 2017
    Nyckelord
    convection, shock waves, methods: numerical, stars: AGB and post-AGB, stars: atmospheres, stars: oscillations
    Nationell ämneskategori
    Astronomi, astrofysik och kosmologi
    Identifikatorer
    urn:nbn:se:uu:diva-324338 (URN)10.1051/0004-6361/201629594 (DOI)000400754000072 ()
    Forskningsfinansiär
    VetenskapsrådetSwedish National Infrastructure for Computing (SNIC), p2013234
    Tillgänglig från: 2017-06-15 Skapad: 2017-06-15 Senast uppdaterad: 2018-04-10Bibliografiskt granskad
    4. Atmospheres and wind properties of non-spherical AGB stars
    Öppna denna publikation i ny flik eller fönster >>Atmospheres and wind properties of non-spherical AGB stars
    (Engelska)Ingår i: Astronomy and Astrophysics, ISSN 0004-6361, E-ISSN 1432-0746Artikel i tidskrift (Refereegranskat) Submitted
    Nationell ämneskategori
    Astronomi, astrofysik och kosmologi
    Identifikatorer
    urn:nbn:se:uu:diva-348123 (URN)
    Tillgänglig från: 2018-04-10 Skapad: 2018-04-10 Senast uppdaterad: 2018-04-10
    5. An extensive grid of DARWIN models for M-type AGB stars: I. Mass loss and the properties of wind and dust
    Öppna denna publikation i ny flik eller fönster >>An extensive grid of DARWIN models for M-type AGB stars: I. Mass loss and the properties of wind and dust
    Visa övriga...
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Nationell ämneskategori
    Astronomi, astrofysik och kosmologi
    Identifikatorer
    urn:nbn:se:uu:diva-348124 (URN)
    Tillgänglig från: 2018-04-10 Skapad: 2018-04-10 Senast uppdaterad: 2018-04-10
  • Disputation: 2018-06-02 10:00 Rudbecksalen, Rudbecklaboratoriet, Uppsala
    Castro, Marco
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för immunologi, genetik och patologi.
    Cellular and molecular roles for CDC42 in angiogenesis2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Angiogenesis is the physiological process by which new blood vessels grow and critically depends on the interplay between the major vascular units: endothelial cells, pericytes and smooth muscle cells. Dysfunction and mispatterning of blood vessels are associated with the progression of many vascular complications, and therefore, understanding the causes of vascular dysmorphia is a central question in vascular biology. CDC42 is a small GTPase known to regulate a diverse array of cellular functions in endothelial cells, however, its contribution to vascular development in vivo remains incompletely understood. The overall aim of this thesis work is to investigate the role of CDC42 during angiogenesis in the central nervous system, using an inducible endothelial-specific Cdc42 knockout model.

    In Paper I, I investigate which CDC42-dependent functions operational in vivo are of relevance for angiogenic sprouting, and how they contribute to blood vessel morphogenesis. Analysis of distinct cellular behaviours shows that CDC42 is critically required for proper EC dispersion in the vasculature and that it regulates sprouting angiogenesis and endothelial axial polarity.

    In Paper II, I explore the in vivo consequences of Cdc42 deletion for vascular morphogenesis, leading to the appearance of capillary-venous malformations in the brain, resembling the human disease of cerebral cavernous malformations. I aimed to understand how this type of vascular malformations arise and was been able to identify the MEKK3-ERK5-KLF2/4 molecular signalling pathway and other cellular events as the trigger factors that may be responsible for these malformations.

    Paper III redirects focus to the physiological roles of another protein, GPR116, in modulating blood-brain barrier permeability and pathologic angiogenesis in the central nervous system.

    In summary, these findings reveal crucial roles of endothelial CDC42 during angiogenesis and further uncover its potential relevance in the molecular pathogenesis of cerebrovascular malformations.

    Delarbeten
    1. Defective endothelial cell migration in the absence of Cdc42 leads to capillary-venous malformations: Cdc42 and vascular malformations
    Öppna denna publikation i ny flik eller fönster >>Defective endothelial cell migration in the absence of Cdc42 leads to capillary-venous malformations: Cdc42 and vascular malformations
    Visa övriga...
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Nyckelord
    Vascular malformations, Cdc42, cell migration, planar-cell-polarity, angiogenesis, proliferation
    Nationell ämneskategori
    Cellbiologi
    Identifikatorer
    urn:nbn:se:uu:diva-347774 (URN)
    Tillgänglig från: 2018-04-06 Skapad: 2018-04-06 Senast uppdaterad: 2018-04-09Bibliografiskt granskad
    2. CDC42 deletion elicits cerebral vascular malformations via increased MEKK3-dependent KLF4 expression
    Öppna denna publikation i ny flik eller fönster >>CDC42 deletion elicits cerebral vascular malformations via increased MEKK3-dependent KLF4 expression
    Visa övriga...
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Nyckelord
    Angiogenesis, vascular morphogenesis, cerebrovascular malformation, endothelial cells, CDC42, MEKK3 signaling, KLF2/4
    Nationell ämneskategori
    Cell- och molekylärbiologi
    Identifikatorer
    urn:nbn:se:uu:diva-347776 (URN)
    Tillgänglig från: 2018-04-06 Skapad: 2018-04-06 Senast uppdaterad: 2018-04-09Bibliografiskt granskad
    3. Gpr116 Receptor Regulates Distinctive Functions in Pneumocytes and Vascular Endothelium
    Öppna denna publikation i ny flik eller fönster >>Gpr116 Receptor Regulates Distinctive Functions in Pneumocytes and Vascular Endothelium
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    2015 (Engelska)Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, nr 9, artikel-id e0137949Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Despite its known expression in both the vascular endothelium and the lung epithelium, until recently the physiological role of the adhesion receptor Gpr116/ADGRF5 has remained elusive. We generated a new mouse model of constitutive Gpr116 inactivation, with a large genetic deletion encompassing exon 4 to exon 21 of the Gpr116 gene. This model allowed us to confirm recent results defining Gpr116 as necessary regulator of surfactant homeostasis. The loss of Gpr116 provokes an early accumulation of surfactant in the lungs, followed by a massive infiltration of macrophages, and eventually progresses into an emphysemalike pathology. Further analysis of this knockout model revealed cerebral vascular leakage, beginning at around 1.5 months of age. Additionally, endothelial-specific deletion of Gpr116 resulted in a significant increase of the brain vascular leakage. Mice devoid of Gpr116 developed an anatomically normal and largely functional vascular network, surprisingly exhibited an attenuated pathological retinal vascular response in a model of oxygen-induced retinopathy. These data suggest that Gpr116 modulates endothelial properties, a previously unappreciated function despite the pan-vascular expression of this receptor. Our results support the key pulmonary function of Gpr116 and describe a new role in the central nervous system vasculature.

    Nationell ämneskategori
    Immunologi inom det medicinska området Kardiologi
    Identifikatorer
    urn:nbn:se:uu:diva-265915 (URN)10.1371/journal.pone.0137949 (DOI)000361792100023 ()26394398 (PubMedID)
    Forskningsfinansiär
    EU, Europeiska forskningsrådet, 294556EU, Europeiska forskningsrådet, ITN-2012-317250-VESSELCancerfondenVetenskapsrådetKnut och Alice Wallenbergs Stiftelse
    Tillgänglig från: 2015-11-04 Skapad: 2015-11-04 Senast uppdaterad: 2018-04-07
  • Disputation: 2018-06-02 10:00 Ihresalen, Uppsala
    Wilhelmsen, Vera
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Språkvetenskapliga fakulteten, Institutionen för lingvistik och filologi.
    A Linguistic Description of Mbugwe with Focus on Tone and Verbal Morphology2018Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    Mbugwe is an endangered Bantu language spoken in north central Tanzania. This PhD dissertation is a description of the Mbugwe language with a focus on tone and verbal morphology, based on the author’s fieldwork. This is the first detailed description of the language. Thus far, only a short grammatical sketch of Mbugwe has been available.

    Mbugwe is a tonal language with a rich verbal system. Therefore, the focus of this dissertation is on tone and verbal morphology. The dissertation also contains a brief description of the phonology of Mbugwe as well as a description of the nominal system. Mbugwe has 7 vowels; length is distinctive. There are 21 consonant phonemes, not counting the NC sequences, which are analysed as clusters in this study. Mbugwe has 17 noun classes and the adnominals that agree with the noun are described and exemplified.

    The tones of the language are presented in detail. Mbugwe has two tones, high and low, and the low tone is considered the default tone. The tone-bearing unit is the mora. High tones spread one mora to the right, and the last high tone before a low tone is upstepped. There is both lexical tone and grammatical tone in Mbugwe, and grammatical tones that occur on the verb stem in certain verb forms are described.

    In the chapter on verb morphology, the structures of the simple and periphrastic verbs are presented, as well as a description of the infinitive and copula verbs. The various tenses, aspects and moods of Mbugwe are then presented. There are 25 affirmative forms and 15 negative forms. For the perfective verbs, there are three past tenses and a future tense. In the imperfective, there is only one past tense, as well as a present and one future tense. Other aspects are the progressive, the habitual and the persistive. Moods that are grammaticalized in Mbugwe are the subjunctive, the imperative and the counterfactual. Verb forms that are not readily categorized as tense, aspect or mood are the consecutive, the situative and the participial. They depend on other verbs for their time reference.

  • Disputation: 2018-06-04 13:15 Hörsal 2, Uppsala
    Magnusson, Eva Maria
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Företagsekonomiska institutionen.
    Vad händer i själva verket?: Om styrning och handlingsutrymme i Skolverket under åren 1991–20142018Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    This thesis deals with questions of governance, control and discretion in state agencies. It is grounded on a case study of the Swedish National Agency for Education (Skolverket), from its prelude in the late 1980s, to its start in 1991, through several governments, seven ministers and four direktor generals, up tp 2014.

    The empirical part of the thesis follows the periods of the four director generals. The study is based on a vast number of documents, supplemented with interviews. For the analysis, a model of governance and control was condensed from the literature. This model attempts to cover both the political governing of agencies and the internal organizational control of agencies. This model was furthermore developed into three ideal type control styles: Old public management/ Agency, New public management/ Actor, and New public governance/ Arena.

    Analysis showed that Skolverket started out as a new type of agency, resembling the ideal type of NPG/ Arena, but over time, with an increasing pressure from the political level, it gradually turned into a more “normal” state agency, at one period resembling the ideal type of NPM/ Actor but finally becoming more similar to the ideal type of OPM/ Agent, however with still strong internal traits of an Arena.

    Further analysis showed that the actual governance and control featured several crucial characteristics that proved to be of importance for the amount of discretion left for the directors and officials of the agency. These characteristics were the degree of 1) unified or plural value systems, 2) partial or comprehensive use of control “tools”, and 3) high or low degree of specificity. These three characteristics were combined into eight different types of roles, each with a specific type and level of discretion, from the most restricted (“Authoritarian”) to the most unrestricted (“Laissez-faire”) and six other roles in between. It is proposed that this scheme of roles form a novel way of analysing the level and distribution of discretion in agencies.

  • Disputation: 2018-06-05 09:00 Häggsalen, Ångströmlaboratoriet, Uppsala
    Mendoza, Victor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Aerodynamic Studies of Vertical Axis Wind Turbines using the Actuator Line Model2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis addresses the unsteady aerodynamics involved in the operation of vertical axis wind turbines (VAWTs). The main focus is to represent and understand the most relevant phenomena within the resulting flow pattern as the wake structure, loads on the different turbine components and the performance of the rotor. An actuator line model has been used for this purpose.

    This model has been validated against experimental measurements from diverse cases with different operating conditions in both confined wind tunnels and open site locations. Numerical works were carried out considering a wide range of tip speed ratios (TSRs), and therefore covering from the no stall to the deep stall regime. The latter requires the implementation of a dynamic stall model for the proper representation of the unsteady forces on the blades. Also, different inlet conditions such as a uniform flow, a logarithmic wind shear and an atmospheric boundary layer (ABL) have been tested. The so-called recycling method technique was used to produce the fully developed ABL flow. Additionally, the resulting wake and performance of interacting turbines has been studied.

    Once the model was validated, two numerical study cases for large scale turbines were carried out. First, the performance and resulting flow field from both a horizontal axis wind turbine (HAWT) and VAWT were investigated when the turbines were operating at their optimal TSR and within the same ABL inflow boundary conditions. The influence of the variation on the atmospheric turbulence levels was also studied, as well as the differences and similarities on the obtained results for both type of turbines. Later, the performance improvement of two interacting VAWTs was investigated through the deflected wake produced by the pitched struts of the upstream turbine. This is presented as a novel mechanism to mitigate losses on interacting turbine arrangements (i.e. wind farms).

    In general, there is a reasonable good agreement between numerical results and experimental measurements, and therefore, the applied ALM can be considered as a potential tool for VAWTs simulations, characterized by relatively low computational cost showing accuracy and numerical stability.

    Delarbeten
    1. Validation of an Actuator Line Model Coupled to a Dynamic Stall Model for Pitching Motions Characteristic to Vertical Axis Turbines
    Öppna denna publikation i ny flik eller fönster >>Validation of an Actuator Line Model Coupled to a Dynamic Stall Model for Pitching Motions Characteristic to Vertical Axis Turbines
    2016 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Vertical axis wind turbines (VAWT) can be used to extract renewable energy from wind flows. A simpler design, low cost of maintenance, and the ability to accept flow from all directions perpendicular to the rotor axis are some of the most important advantages over conventional horizontal axis wind turbines (HAWT). However, VAWT encounter complex and unsteady fluid dynamics, which present significant modeling challenges. One of the most relevant phenomena is dynamic stall, which is caused by the unsteady variation of angle of attack throughout the blade rotation, and is the focus of the present study. Dynamic stall is usually used as a passive control for VAWT operating conditions, hence the importance of predicting its effects. In this study, a coupled model is implemented with the open-source CFD toolbox OpenFOAM for solving the Navier-Stokes equations, where an actuator line model and dynamic stall model are used to compute the blade loading and body force. Force coefficients obtained from the model are validated with experimental data of pitching airfoil in similar operating conditions as an H-rotor type VAWT. Numerical results show reasonable agreement with experimental data for pitching motion.

    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-305170 (URN)10.1088/1742-6596/753/2/022043 (DOI)
    Konferens
    The Science of Making Torque from Wind (TORQUE 2016)
    Forskningsfinansiär
    StandUp for Wind
    Tillgänglig från: 2016-10-12 Skapad: 2016-10-12 Senast uppdaterad: 2018-04-17Bibliografiskt granskad
    2. Wake Flow Simulation of a Vertical Axis Wind Turbine Under the Influence of Wind Shear
    Öppna denna publikation i ny flik eller fönster >>Wake Flow Simulation of a Vertical Axis Wind Turbine Under the Influence of Wind Shear
    2017 (Engelska)Ingår i: Journal of Physics: Conference Series, Volume 854, conference 1, 2017Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    The current trend of the wind energy industry aims for large scale turbines installed in wind farms. This brings a renewed interest in vertical axis wind turbines (VAWTs) since they have several advantages over the traditional Horizontal Axis Wind Tubines (HAWTs) for mitigating the new challenges. However, operating VAWTs are characterized by complex aerodynamics phenomena, presenting considerable challenges for modeling tools. An accurate and reliable simulation tool for predicting the interaction between the obtained wake of an operating VAWT and the flow in atmospheric open sites is fundamental for optimizing the design and location of wind energy facility projects. The present work studies the wake produced by a VAWT and how it is affected by the surface roughness of the terrain, without considering the effects of the ambient turbulence intensity. This study was carried out using an actuator line model (ALM), and it was implemented using the open-source CFD library OpenFOAM to solve the governing equations and to compute the resulting flow fields. An operational H-shaped VAWT model was tested, for which experimental activity has been performed at an open site north of Uppsala-Sweden. Different terrains with similar inflow velocities have been evaluated. Simulated velocity and vorticity of representative sections have been analyzed. Numerical results were validated using normal forces measurements, showing reasonable agreement.

    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-348342 (URN)10.1088/1742-6596/854/1/012031 (DOI)
    Konferens
    Wake Conference 2017, Visby, May 30-June 1, 2017.
    Forskningsfinansiär
    StandUp for Wind
    Tillgänglig från: 2018-04-11 Skapad: 2018-04-11 Senast uppdaterad: 2018-04-17Bibliografiskt granskad
    3. Near-Wake Flow Simulation of a Vertical Axis Turbine Using an Actuator Line Model
    Öppna denna publikation i ny flik eller fönster >>Near-Wake Flow Simulation of a Vertical Axis Turbine Using an Actuator Line Model
    (Engelska)Ingår i: Wind Energy, ISSN 1095-4244, E-ISSN 1099-1824Artikel i tidskrift (Refereegranskat) Submitted
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-348688 (URN)
    Forskningsfinansiär
    StandUp for Wind
    Tillgänglig från: 2018-04-17 Skapad: 2018-04-17 Senast uppdaterad: 2018-05-10
    4. Validation of an Actuator Line and Vortex Model using Normal ForcesMeasurements of a Straight-Bladed Vertical Axis Wind Turbine
    Öppna denna publikation i ny flik eller fönster >>Validation of an Actuator Line and Vortex Model using Normal ForcesMeasurements of a Straight-Bladed Vertical Axis Wind Turbine
    (Engelska)Ingår i: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682Artikel i tidskrift (Refereegranskat) Submitted
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-348689 (URN)
    Tillgänglig från: 2018-04-17 Skapad: 2018-04-17 Senast uppdaterad: 2018-04-17
    5. Performance and Wake Comparison of Horizontal and VerticalAxis Wind Turbines Under the Influence of the AtmosphericBoundary Layer
    Öppna denna publikation i ny flik eller fönster >>Performance and Wake Comparison of Horizontal and VerticalAxis Wind Turbines Under the Influence of the AtmosphericBoundary Layer
    (Engelska)Ingår i: Wind Energy, ISSN 1095-4244, E-ISSN 1099-1824Artikel i tidskrift (Refereegranskat) Submitted
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-348690 (URN)
    Forskningsfinansiär
    StandUp for Wind
    Tillgänglig från: 2018-04-17 Skapad: 2018-04-17 Senast uppdaterad: 2018-05-10
    6. Improving Farm Efficiency of Interacting Vertical Axis Wind Turbines Through Wake Deflection Using Pitched Struts
    Öppna denna publikation i ny flik eller fönster >>Improving Farm Efficiency of Interacting Vertical Axis Wind Turbines Through Wake Deflection Using Pitched Struts
    (Engelska)Ingår i: Wind Energy, ISSN 1095-4244, E-ISSN 1099-1824Artikel i tidskrift (Övrigt vetenskapligt) Submitted
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:uu:diva-348692 (URN)
    Forskningsfinansiär
    StandUp for Wind
    Tillgänglig från: 2018-04-17 Skapad: 2018-04-17 Senast uppdaterad: 2018-05-10
  • Disputation: 2018-06-05 09:15 B21, BMC, Uppsala
    Jonsson, Henrik
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för farmaci.
    Confined Compression of Single Particles: Development of a Novel Triaxial Testing Instrument and Particle-Scale Modelling2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    When predicting the performance of a powder compaction process, assessing the behaviour of the particles comprising the powder bed is of central relevance. Currently, however, no experimental methods are available for mimicking the multiaxial loading conditions imposed on the individual particles in a powder bed during compaction, and such analyses are therefore usually performed in silico. Thus, the purpose of this thesis is to introduce a novel experimental method that enables experimental evaluation of confined triaxial loading conditions on individual particles in the mm-scale.

    The work underlying the thesis consists of three major parts. Firstly, the triaxial instrument was designed and developed, after which its performance was evaluated using nominally ideal elastic-plastic spheres as model materials. These initial experiments showed that the instrument was able to successfully impose confined triaxial conditions on the particles, something that was verified by finite element method (FEM) simulations.

    Secondly, the triaxial instrument was used to investigate differences in deformation characteristics under uniaxial and triaxial loading conditions for four different microcrystalline cellulose (MCC)-based granules. It was shown that fragmentation, associated with unconfined uniaxial compression, was impeded under confined triaxial conditions, despite the emergence of cracks. In addition, it was observed that the primary crack always occurs in a plane parallel to the most deformed direction, and that the location of the largest pore has a pronounced influence on the path of the crack.

    Thirdly, the influence of different triaxial loading ratios were evaluated on polymer spheres, after which a unified description of contact pressure development was devised. Data from these experiments were then successfully used to calibrate a contact model for simulating bulk powder compression with the discrete element method (DEM).

    All in all, a novel experimental method has been established, which has proven useful as an alternative and complement to numerical studies when studying single particle deformation under confined triaxial conditions.

    Delarbeten
    1. An apparatus for confined triaxial testing of single particles
    Öppna denna publikation i ny flik eller fönster >>An apparatus for confined triaxial testing of single particles
    Visa övriga...
    2015 (Engelska)Ingår i: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 270, s. 121-127Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A novel triaxial apparatus employing overlapping rigid boundaries has been designed and constructed for experimental measurement of contact forces under confined compression of single granules in the mm-scale. The performance of the apparatus was evaluated by performing uniaxial and triaxial compression experiments on ideal elastic-plastic materials. Compression curves were compared with the fully plastic Abbott-Firestone contact model and with results from FEM simulations. The increase in contact force associated with confined conditions was observed in the compression curves from triaxial compression experiments, as supported by predictions from simulations using single particle contact models. Hence, a new method for the assessment of mechanical behaviour of single particles under confined compression can be considered as established.

    Nyckelord
    Compression, Triaxial, Single particles, Confined conditions, Apparatus design, Contact mechanics
    Nationell ämneskategori
    Farmaceutiska vetenskaper
    Identifikatorer
    urn:nbn:se:uu:diva-239203 (URN)10.1016/j.powtec.2014.10.016 (DOI)000347579300014 ()
    Forskningsfinansiär
    Vetenskapsrådet, 621-2011-4049
    Tillgänglig från: 2014-12-19 Skapad: 2014-12-19 Senast uppdaterad: 2018-04-12Bibliografiskt granskad
    2. Investigations of single microcrystalline cellulose-based granules subjected to confined triaxial compression
    Öppna denna publikation i ny flik eller fönster >>Investigations of single microcrystalline cellulose-based granules subjected to confined triaxial compression
    2016 (Engelska)Ingår i: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 289, s. 79-87Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Confined triaxial compression of single granules was performed in order to assess the contact force development and modes of granule deformation under these conditions. In the study, four microcrystalline cellulose-based granule types of different characteristics were investigated. Results from triaxial single-granule compression experiments were evaluated using an analytical model as well as by comparison to unconfined single-granule compression and to confined bulk compression experiments. It was observed that single granules deform and densify, but tend to keep their integrity during confined triaxial compression, as evident from both compression data and from morphological analysis. Results from confined single granule compression were well represented by the analytical model. These results also largely reflected those from bulk compression experiments, including features of the force-displacement curves as well as rank order between the granule types in terms of contact stiffness. Furthermore, it was shown that intragranular porosity to a high extent governs the onset of plastic incompressibility.

    Nyckelord
    Compression, Triaxial, Hydrostatic, Single granules, Confined conditions, Contact mechanics
    Nationell ämneskategori
    Farmaceutiska vetenskaper
    Identifikatorer
    urn:nbn:se:uu:diva-280895 (URN)10.1016/j.powtec.2015.11.051 (DOI)000370095400012 ()
    Forskningsfinansiär
    Vetenskapsrådet, 621-2011-4049
    Tillgänglig från: 2016-03-16 Skapad: 2016-03-16 Senast uppdaterad: 2018-04-12Bibliografiskt granskad
    3. Mechanical behaviour of ideal elastic-plastic particles subjected to different triaxial loading conditions
    Öppna denna publikation i ny flik eller fönster >>Mechanical behaviour of ideal elastic-plastic particles subjected to different triaxial loading conditions
    2017 (Engelska)Ingår i: Powder Technology, ISSN 0032-5910, E-ISSN 1873-328X, Vol. 315, s. 347-355Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The contact force development for two types of polymeric elastoplastic particles subjected to different triaxial loading conditions was studied experimentally utilising a unique triaxial testing apparatus. In order to evaluate the experimental results, a finite element analysis was performed. The experimental findings highlighted the importance of contact dependence, which manifested itself in two principally different ways. Firstly, a reduced stiffness was observed when plastic deformation ceased to be fully contained, which, depending on the loading conditions, occurred at an engineering strain of about 5-10%. Secondly, a markedly increased stiffness was observed when particle confinement inhibited further plastic deformation, making elastic volume reduction the predominant deformation mode. The experimental results could be well reproduced by the numerical simulations, provided that isotropic hardening was included in the elastoplastic model. In an attempt to invariantly describe the data, a nominal contact pressure was determined as a function of the volumetric constraint of the particle. This resulted in an adequate collapse of results obtained for different loading conditions onto a single master curve at large volumetric constraint. In summary, this paper should be considered as a step along the pathway towards our long term goal of introducing novel and improved contact models.

    Nyckelord
    Particle mechanics, Triaxial, Compression, Spatial confinement, Contact dependence
    Nationell ämneskategori
    Teknisk mekanik
    Identifikatorer
    urn:nbn:se:uu:diva-323755 (URN)10.1016/j.powtec.2017.04.005 (DOI)000401593600041 ()
    Forskningsfinansiär
    Vetenskapsrådet, 621-2011-4049
    Tillgänglig från: 2017-06-13 Skapad: 2017-06-13 Senast uppdaterad: 2018-04-12Bibliografiskt granskad
    4. Crack nucleation and propagation in microcrystalline-cellulose based granules subject to uniaxial and triaxial load
    Öppna denna publikation i ny flik eller fönster >>Crack nucleation and propagation in microcrystalline-cellulose based granules subject to uniaxial and triaxial load
    Visa övriga...
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Cracking patterns of four kinds of granules, based on the common pharmaceutical excipient microcrystalline cellulose (MCC) and subject to compressive load, were examined. The initial pore structure and the location of initial failure under uniaxial compression were assessed using X-ray micro-computed tomography, whereas contact force development and onset of cracking under more complex compressive load were examined using a triaxial testing apparatus. Smoothed particle hydrodynamics (SPH) simulations were employed for numerical analysis of the stress distributions prior to cracking. For granules subject to uniaxial compression, initial cracking always occurred along the meridian and the precise location of the crack depended on the pore structure. Likewise, for granules subject to triaxial compression, the fracture plane of the primary crack was generally parallel to the dominant loading direction. The occurrence of cracking was highly dependent on the triaxiality ratio, i.e. the ratio between the punch displacements in the secondary and dominant loading directions. Compressive stresses in the lateral directions, induced by triaxial compression, prevented crack opening and fragmentation of the granule, something that could be verified in the SPH simulations. These results provide corroboration as well as further insights into previously observed differences between confined and unconfined compression of granular media.

    Nationell ämneskategori
    Farmaceutiska vetenskaper
    Forskningsämne
    Galenisk farmaci
    Identifikatorer
    urn:nbn:se:uu:diva-347457 (URN)
    Tillgänglig från: 2018-04-03 Skapad: 2018-04-03 Senast uppdaterad: 2018-04-12
    5. Evaluation of bulk compression using a discrete element procedure calibrated with data from triaxial experiments on single particles
    Öppna denna publikation i ny flik eller fönster >>Evaluation of bulk compression using a discrete element procedure calibrated with data from triaxial experiments on single particles
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Confined compression of bimodal mixtures of ideal spherical cellulose acetate (CA) particles (diameters 1.5 and 2.0 mm) was studied numerically with the discrete element method (DEM) and experimentally using a materials tester equipped with suitable tablet tooling. An extended truncated sphere contact model was used in the simulations, enabling them to be carried out to high relative densities (approaching and sometimes exceeding unity). In order to calibrate this model, the contact pressure development was extracted from prior experimental investigations on single 2.0-mm large CA particles. Results from the simulations were evaluated with the Kawakita and Heckel compression equations and compared to the corresponding data obtained from bulk compression experiments. Generally, a high degree of similarity between experiments and simulations was observed, showing the usefulness of combining confined single particle compression experiments with a suitable numerical model when predicting the performance of powder compression to high relative densities.

    Nationell ämneskategori
    Farmaceutiska vetenskaper
    Identifikatorer
    urn:nbn:se:uu:diva-347458 (URN)
    Tillgänglig från: 2018-04-03 Skapad: 2018-04-03 Senast uppdaterad: 2018-04-12
  • Disputation: 2018-06-05 10:00 Hambergssalen, Uppsala
    Svensson, Nina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten och landskapslära.
    Mesoscale Processes over the Baltic Sea2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The objective of this thesis is to study mesoscale processes above the Baltic Sea, which is a small, semi-enclosed sea where land-sea interaction may have a large impact on the offshore conditions. It is only the last tens of years that offshore research has become more popular, and one reason for this is the increasing offshore wind energy, which poses the need for accurate estimates of wind speed and turbulence conditions in the marine environment. In this thesis a range of mesoscale processes over the Baltic Sea are studied using the mesoscale model WRF (Weather Research and Forecasting) and different types of measurements.It is found that mesoscale effects are largest during spring and summer, when stable conditions dominate. The whole Baltic sea surface is affected by warm-air advection and low-level jets. There is very little spatial variation in seasonally averaged fields, which shows that the extent of mesoscale effects is several hundred kilometres. Wind speed and temperature profiles can thus not be described solely by the local conditions even far out over sea surface. Sea breezes are relatively unimportant for modyfing the seasonally averaged wind fields, but other types of low-level jets have a large influence. Results show that most of the low-level jets are likely created by inertial oscillations initiated when air flows across a coastline from the convective land surface to stable sea surface.Evaluation of the model shows that the discrepancies are largest during very stable conditions, but are also quite large during very unstable. The reasons for this are discussed.Several cases of boundary layer rolls are investigated using measurements and simulations and it is found that the rolls are likely created over the convective mainland and advected out over the stable sea surface, which may be a new finding that has not been reported before.

    Delarbeten
    1. Stable conditions over the Baltic sea: model evaluation and climatology
    Öppna denna publikation i ny flik eller fönster >>Stable conditions over the Baltic sea: model evaluation and climatology
    2016 (Engelska)Ingår i: Boreal environment research, ISSN 1239-6095, E-ISSN 1797-2469, Vol. 21, s. 387-404Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The WRF (Weather Research and Forecasting model) was evaluated against flight measurements over the Baltic Sea during stable conditions, focusing on vertical profiles of temperature and wind speed. Six different boundary layer parameterization schemes were used. It is shown that there are generally small differences between the boundary layer schemes, and that all schemes have problems in capturing the strength and height of low-level jets. Climatological simulations over the Baltic Sea show that there is a strong sea-sonality in the stability over the sea with up to 80% stable conditions in spring as compared with 10% in winter. Low-level jets are common, and occur up to 45% of the time in spring. The entire Baltic Sea, not only its coastal areas, is affected by stable stratification.

    Nyckelord
    stable conditions, boundary layer, Baltic sea, WRF, low level jet, coastal area
    Nationell ämneskategori
    Meteorologi och atmosfärforskning
    Forskningsämne
    Meteorologi
    Identifikatorer
    urn:nbn:se:uu:diva-287952 (URN)
    Forskningsfinansiär
    StandUp for WindNational Supercomputer Centre (NSC), Sweden, SNIC 2015/1-224
    Tillgänglig från: 2016-04-27 Skapad: 2016-04-27 Senast uppdaterad: 2018-04-12
    2. A Case Study of Offshore Advection of Boundary Layer Rolls over a Stably Stratified Sea Surface
    Öppna denna publikation i ny flik eller fönster >>A Case Study of Offshore Advection of Boundary Layer Rolls over a Stably Stratified Sea Surface
    Visa övriga...
    2017 (Engelska)Ingår i: Advances in Meteorology, ISSN 1687-9309, E-ISSN 1687-9317, Vol. 2017, artikel-id 9015891Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Streaky structures of narrow (8-9 km) high wind belts have been observed from SAR images above the Baltic Sea during stably stratified conditions with offshore winds from the southern parts of Sweden. Case studies using the WRF model and in situ aircraft observations indicate that the streaks originate from boundary layer rolls generated over the convective air above Swedish mainland, also supported by visual satellite images showing the typical signature cloud streets. The simulations indicate that the rolls are advected and maintained at least 30-80 km off the coast, in agreement with the streaks observed by the SAR images. During evening when the convective conditions over land diminish, the streaky structures over the sea are still seen in the horizontal wind field; however, the vertical component is close to zero. Thus advected feature from a land surface can affect the wind field considerably for long times and over large areas in coastal regions. Although boundary layer rolls are a well-studied feature, no previous study has presented results concerning their persistence during situations with advection to a strongly stratified boundary layer. Such conditions are commonly encountered during spring in coastal regions at high latitudes.

    Nyckelord
    boundary layer rolls, coastal transition, stable conditions
    Nationell ämneskategori
    Meteorologi och atmosfärforskning
    Forskningsämne
    Meteorologi
    Identifikatorer
    urn:nbn:se:uu:diva-306939 (URN)10.1155/2017/9015891 (DOI)000414082500001 ()
    Projekt
    StandUp for Wind
    Forskningsfinansiär
    National Supercomputer Centre (NSC), Sweden, 2015/1-224StandUp for Wind
    Tillgänglig från: 2016-11-07 Skapad: 2016-11-07 Senast uppdaterad: 2018-04-12Bibliografiskt granskad
    3. Modification of the Baltic Sea wind field by land-sea interaction
    Öppna denna publikation i ny flik eller fönster >>Modification of the Baltic Sea wind field by land-sea interaction
    (Engelska)Ingår i: Artikel i tidskrift (Refereegranskat) Submitted
    Nationell ämneskategori
    Meteorologi och atmosfärforskning
    Identifikatorer
    urn:nbn:se:uu:diva-348369 (URN)
    Tillgänglig från: 2018-04-12 Skapad: 2018-04-12 Senast uppdaterad: 2018-04-12
    4. Offshore wind speed profiles: Investigating variations using WRF simulations and LIDAR measurements
    Öppna denna publikation i ny flik eller fönster >>Offshore wind speed profiles: Investigating variations using WRF simulations and LIDAR measurements
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Nationell ämneskategori
    Meteorologi och atmosfärforskning
    Identifikatorer
    urn:nbn:se:uu:diva-348372 (URN)
    Tillgänglig från: 2018-04-12 Skapad: 2018-04-12 Senast uppdaterad: 2018-04-12
  • Disputation: 2018-06-05 10:15 Brusewitz, Uppsala
    Wangel, Marcus
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Statsvetenskapliga institutionen.
    Deep Roots and Tangled Branches: Bureaucracy and Collaboration in Natural Resource Governance in South India2018Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    This is a study about collaboration within bureaucracies tasked with natural resource management in the contemporary Global South. It seeks to fill a considerable knowledge gap in the extant literature by exploring how individual public officials perceive the policy environment they work in. These individuals face multiple pressures to work more collaboratively yet the ways in which they are incentivised and develop goals and strategies for collaboration have been neglected in past research. A deeper understanding of this process is essential as public officials are largely responsible for implementing policies ensuring the welfare of millions of deprived people in rural areas, and for safeguarding the sustainable use of the natural commons.

    This book is an institutional analysis of the drivers of collaboration at the individual level. It builds on immersive ethnographic fieldwork on the forest bureaucracy in Kerala, South India where field observations and ninety interviews were conducted with state forest officials. The empirical analysis finds that the majority of officials are in favour of working more collaboratively for a plurality of reasons, but perceive themselves constrained by the formal institutional setup of the forest bureaucracy. To mitigate these limitations forest officials design numerous boundary-spanning, informal networks that function as vehicles of institutionalised coordination and collaboration.

    Importantly, the officials develop preferences for joint action on policy issues which they perceive the formal organisation is incapable of delivering, not least improved forest livelihoods. These findings are a significant contribution and stand in contrast to most previous related research which has focused on issues of bureaucratic malfeasance in the context of natural resource governance. The findings are also noteworthy as they point to a rich variety of more nuanced roles and abilities individual public officials in India may hold, beyond that of the stereotype corrupt bureaucrat.

    In addition to the contextualised and vivified empirical description of informal collaboration this study makes two additional contributions. First, it highlights and demonstrates the utility of an ethnographic approach to the study of informal institutions and institutionally constrained behaviour in settings that are little studied and hard to access. Second, it contributes to theoretical discussions on the interplay between formal and informal institutions. In particular this concerns the rationality and necessity of informal strategies when formal institutional frameworks impose constraints on individual agents or lack the capacity to solve complex problems.

  • Disputation: 2018-06-05 13:15 Hörsal 2, Ekonomikum, Uppsala
    Edlund, Peter
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Företagsekonomiska institutionen.
    Constructing an Arbiter of Status: A Study of the European Research Council's Emergence in the Field of Science2018Doktorsavhandling, monografi (Övrigt vetenskapligt)
    Abstract [en]

    The aim of this thesis is to shed light on how certain actors are constructed into third-party arbiters of status. Such arbiters mediate the triadic relations in which status is created, assessing and suggesting certain candidates as particularly worthy of deference from audiences.

    While previous literature has provided us with compelling insights into the pervasive authority of status arbiters, less attention has been paid to the ways in which these arbiters reach their authoritative positions. I seek to build new knowledge on the processes through which third-party status arbiters are constructed by exploring how the European Research Council (ERC) was transformed into an authority in science. In a short period of time, the ERC’s evaluations of funding applications and subsequent allocations of research resources came to be approached as a benchmark of scientific quality, which scientists, departments, universities, and countries anxiously compared their research performance with. I suggest that these evaluations and allocations soon became more than instances in which quality was assessed and resources were distributed, thus turning into potent bases for status creation as well.

    In three empirical chapters, which draw upon documents, interviews, and observations, I place the ERC within the context of a field, showing how its construction into a third-party status arbiter needs to be understood as a process that unfolded over time. First, I look at major tensions and struggles that surrounded Europe-level science in the advent of the ERC’s founding. Then, I examine the active efforts with which the ERC attempted to engender acceptance for its evaluations of Starting Grant (StG) funding applications. Finally, I explore the status consequences of ERC StG allocations for the careers of scientists, the milieus within departments, and the relations between universities in Sweden.

    My findings contribute to previous literature by demonstrating how arbiters are constructed through mutually reinforcing relations in which the status-creating potential of evaluations is continuously framed and validated. My findings also contribute by showing how the creation of status over time requires constant maintenance efforts to sustain the agreement between arbiters and audiences in terms of candidates that are worthy of deference.

  • Disputation: 2018-06-06 09:15 Enghoffsalen, Uppsala
    Schiller, Petter
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för kirurgiska vetenskaper, Thoraxkirurgi.
    Mechanical Circulatory Support in Left Ventricular Heart Failure2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Short-term mechanical circulatory support (MCS) with ventricular assist devices or veno-arterial extracorporeal membrane oxygenation (VA ECMO) has become the standard treatment in patients with cardiogenic shock unresponsive to pharmacological treatment. However, the haemodynamic effects of these devices are not yet fully described, nor are their effects on ventricular function and myocardial recovery.

    The aims of this thesis are to increase knowledge of the haemodynamic changes during MCS in different settings and to provide new insights into how MCS therapy should be guided in the specific patient.

    In Studies I and II, we developed experimental animal models to investigate the effect of VA ECMO on left ventricular (LV) performance and size of myocardial infarction in different cannulation strategies. In Study I, we found that the LV performance was negatively affected by VA ECMO in both centrally and peripherally cannulated animals. In Study II, we specifically studied the effect of VA ECMO with and without the addition of LV drainage on the size of experimentally induced myocardial infarction. The results showed that active LV decompression had no effect on infarct size in the acute setting.

    Studies III and IV are retrospective studies on patients in cardiogenic shock treated with short-term mechanical support with either Impella® (Studies III and IV) or VA ECMO (Study IV). In Study IV, we concluded that treatment with Impella® has excellent effects on haemodynamic parameters and an acceptable mortality and complication rate. The studied pre-implantation patient parameters did not significantly affect outcome. In Study IV, we compared the outcome of patients treated with Impella® with those treated with VA ECMO. After adjustment for pre-implantation patient status, as defined by SAVE score, no difference in short- or long-term mortality was seen between the two groups.

    In conclusion, VA ECMO, whether central or peripheral, negatively affects the LV, and the addition of a LV drain has no effect on infarct size in these experimental models. Both Impella® and VA ECMO offer good haemodynamic results with acceptable mortality and complication rates in patients with refractory cardiogenic shock. When adjusted for the SAVE score, the outcomes of both treatment modalities are comparable.

    Delarbeten
    1. Experimental Venoarterial Extracorporeal Membrane Oxygenation Induces Left Ventricular Dysfunction
    Öppna denna publikation i ny flik eller fönster >>Experimental Venoarterial Extracorporeal Membrane Oxygenation Induces Left Ventricular Dysfunction
    2016 (Engelska)Ingår i: ASAIO journal (1992), ISSN 1058-2916, E-ISSN 1538-943X, Vol. 62, nr 5, s. 518-524Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Venoarterial extracorporeal membrane oxygenation (VA-ECMO) has experienced an increased use in acute cardiac failure. There are some reports on negative effects of VA-ECMO on cardiac function, such as left ventricular (LV) dilatation and cardiac stun, but the support in the literature is scarce. This study investigates the effects of experimental VA-ECMO on LV function in both peripheral and central cannulation. Ten pigs were randomized to VA-ECMO by either peripheral cannulation through the femoral vessels or central cannulation in the right atrium and ascending aorta. Left ventricular performance was measured with pressure-volume catheters during 5 hours of VA-ECMO. The LV enddiastolic and end-systolic volumes increased comparably in both groups during ECMO. Left ventricular ejection fraction, stroke work, and maximum rate of pressure change decreased comparably in both groups as a function of time on ECMO. The site of cannulation had no impact on the LV response to ECMO. In conclusion, VA-ECMO increased LV volumes and reduced LV function, irrespective of cannulation site in this experimental model. Reduced LV ejection fraction and stroke work indicated LV dysfunction during ECMO.

    Nyckelord
    extracorporeal membrane oxygenation, cannulation, left ventricle, left ventricular assist device
    Nationell ämneskategori
    Kardiologi
    Identifikatorer
    urn:nbn:se:uu:diva-310680 (URN)10.1097/MAT.0000000000000392 (DOI)000387874900006 ()27195745 (PubMedID)
    Tillgänglig från: 2017-01-09 Skapad: 2016-12-19 Senast uppdaterad: 2018-04-12Bibliografiskt granskad
    2. Left Ventricular Decompression during Extracorporeal Membrane Oxygenation (ECMO) Treatment does not Reduce Size of Myocardial Infarction in an Experimental Model
    Öppna denna publikation i ny flik eller fönster >>Left Ventricular Decompression during Extracorporeal Membrane Oxygenation (ECMO) Treatment does not Reduce Size of Myocardial Infarction in an Experimental Model
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Nationell ämneskategori
    Kardiologi
    Identifikatorer
    urn:nbn:se:uu:diva-347425 (URN)
    Tillgänglig från: 2018-04-02 Skapad: 2018-04-02 Senast uppdaterad: 2018-04-12
    3. The Impella® Recover mechanical assist device in acute cardiogenic shock: a single-centre experience of 66 patients
    Öppna denna publikation i ny flik eller fönster >>The Impella® Recover mechanical assist device in acute cardiogenic shock: a single-centre experience of 66 patients
    2016 (Engelska)Ingår i: Interactive Cardiovascular and Thoracic Surgery, ISSN 1569-9293, E-ISSN 1569-9285, Vol. 22, nr 4, s. 452-458Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    OBJECTIVES: Short-term ventricular assist devices are more frequently used in patients with acute cardiogenic shock. The aim of this study was to evaluate its effect on haemodynamic parameters, as well as the short- and long-term outcome and complication rate associated with the device. METHODS: All patients treated with the ImpellaA (R) Recover device at our centre from 2003 to 2014 (n = 66) were included in this study, and follow-up time was 2.9 (+/- 0.4) years. Data were obtained through patient records and the population register. Patient-related factors, preimplantation and early postimplantation haemodynamic and biochemical parameters were analysed. Characteristics of survivors and non-survivors were compared. RESULTS: The device was implanted in 66 patients and 58% (38/66) were alive at 30 days post-implantation. The mean duration of support was 7.4 (+/- 0.8) days. Mean time in the intensive care unit was 24 (+/- 4) days. Following device implantation, patients' cardiac index improved from 2.1 l/min/m(2) (+/- 0.20) to 3.8 l/min/m(2) (+/- 0.20) at Day 7, mixed venous saturation increased from 56% (+/- 2.0) to 68% (+/- 1.2) and diuresis increased from 69 ml/h (+/- 9) at device insertion to 105 ml/h (+/- 19) at Day 7 on support. Central venous pressure, lactate levels and inotropic support decreased on support. No difference between survivors and non-survivors was established. No correlation was established between preimplant parameters and 30-day mortality. CONCLUSIONS: The ImpellaA (R) Recover device improved haemodynamics in patients with acute cardiogenic shock. Still, 30-day mortality remains high and future studies must focus on the optimal timing of placement of the device.

    Nyckelord
    Heart failure, Acute cardiogenic shock, Left ventricular assist device
    Nationell ämneskategori
    Kardiologi
    Identifikatorer
    urn:nbn:se:uu:diva-296864 (URN)10.1093/icvts/ivv305 (DOI)000374228700013 ()26763043 (PubMedID)
    Tillgänglig från: 2016-06-20 Skapad: 2016-06-20 Senast uppdaterad: 2018-04-12Bibliografiskt granskad
    4. Survival after Refractory Cardiogenic Shock is Comparable in Patients with Impella® and Veno-Arterial Extracorporeal Membrane Oxygenation (ECMO) - when Adjusted for SAVE-score
    Öppna denna publikation i ny flik eller fönster >>Survival after Refractory Cardiogenic Shock is Comparable in Patients with Impella® and Veno-Arterial Extracorporeal Membrane Oxygenation (ECMO) - when Adjusted for SAVE-score
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Nationell ämneskategori
    Kardiologi
    Identifikatorer
    urn:nbn:se:uu:diva-347426 (URN)
    Tillgänglig från: 2018-04-02 Skapad: 2018-04-02 Senast uppdaterad: 2018-04-12
  • Disputation: 2018-06-07 09:00 Häggsalen, Uppsala
    Robo, Céline
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Tillämpad materialvetenskap.
    Bone-compliant cements for vertebral augmentation2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Acrylic bone cement based on poly(methyl methacrylate) (PMMA) is commonly used during vertebral augmentation procedures for the treatment of osteoporosis-induced vertebral compression fractures. However, the high stiffness of the cement compared to that of the surrounding trabecular bone is presumed to facilitate the formation of new fractures shortly after surgery. The aim of the thesis was to develop and evaluate a PMMA-based bone cement that better matches the mechanical properties of vertebral trabecular bone. To fulfill this objective, different compounds were added to the initial formulation of bone cement to modify its functional properties. Linoleic acid (LA) was found to give the best combination of strength and stiffness without negative effects on the handling properties and its use was therefore further investigated. In particular, different application-specific mechanical properties of LA-modified cement as well as itsin vivoperformance in an ovine model were assessed. 

    In summary, LA-modified cement exhibited bone-compliant mechanical properties immediately after incorporation of the additive, as well as adequate handling properties, in particular a lower polymerization temperature and appropriate setting time. The screw pullout strength from low-modulus cement was substantially reduced compared to regular PMMA cement, but comparable to some calcium phosphate based cements. The fatigue limit of LA-modified cement was considerably lower compared to regular PMMA bone cement when tested in physiological solution, but still higher than stresses measured in the spine during daily activities. The modified cement displayed similar inflammatory response in vivoto conventional cement, with no evidence of additional cytotoxicity due to the presence of LA. Finally, it was possible to sterilize the additive without significantly compromising its function in the PMMA cement.

    The results from this thesis support further evaluation of the material towards the intended clinical application. 

    Delarbeten
    1. The effect of unsaturated fatty acid and triglyceride oil addition on the mechanical and antibacterial properties of acrylic bone cements
    Öppna denna publikation i ny flik eller fönster >>The effect of unsaturated fatty acid and triglyceride oil addition on the mechanical and antibacterial properties of acrylic bone cements
    Visa övriga...
    2015 (Engelska)Ingår i: Journal of biomaterials applications, ISSN 0885-3282, E-ISSN 1530-8022, Vol. 30, nr 3, s. 279-289Artikel i tidskrift (Refereegranskat) Published
    Nationell ämneskategori
    Textil-, gummi- och polymermaterial Annan materialteknik
    Forskningsämne
    Teknisk fysik med inriktning mot materialvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-251353 (URN)10.1177/0885328215581316 (DOI)000361767300003 ()
    Forskningsfinansiär
    EU, FP7, Sjunde ramprogrammet, FP7-PEOPLE-2010-268134VINNOVA, 2010-02073Stiftelsen för internationalisering av högre utbildning och forskning (STINT), IG2011-2047
    Tillgänglig från: 2015-04-16 Skapad: 2015-04-16 Senast uppdaterad: 2018-04-20Bibliografiskt granskad
    2. In vivo response to a low-modulus PMMA bone cement in an ovine model
    Öppna denna publikation i ny flik eller fönster >>In vivo response to a low-modulus PMMA bone cement in an ovine model
    2018 (Engelska)Ingår i: Acta Biomaterialia, ISSN 1742-7061, E-ISSN 1878-7568, Vol. 72, s. 362-370Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm)) Published
    Abstract [en]

    Poly(methyl methacrylate) (PMMA) is the most commonly used material for the treatment of osteoporosis-induced vertebral compression fractures. However, its high stiffness may introduce an increased risk of adjacent vertebral fractures post-surgery. One alternative in overcoming this concern is the use of additives. This presents its own challenge in maintaining an adequate biocompatibility when modifying the base cement. The aim of this study was to evaluate the in vivobiocompatibility of linoleic acid (LA)-modified acrylic bone cement using a large animal model for the first time, in order to further advance towards clinical use. A worst-case approach was used, choosing a slow-setting base cement. The in vitro monomer release from the cements was also assessed. Additional material characterization, including mechanical tests, are summarized in Appendix A. Unmodified and LA-modified cements were injected into a total of 56 bone defects created in the femur and humerus of sheep. Histopathologic and histomorphometric analysis indicated that LA-modified cement showed a harmless tissue response similar to that of the unmodified cement. Adjacent bone remodeling was observed microscopically 4 weeks after implantation, suggesting a normal healing process of the bone tissues surrounding the implant. LA-modified cement exhibited lower mechanical properties, with a reduction in the elastic modulus of up to 65%. The handling properties were slightly modified without negatively affecting the injectability of the base cement. LA-modified bone cement showed good biocompatibility as well as bone compliant mechanical properties and may therefore be a promising material for the treatment of osteoporotic vertebral fractures. 

    Ort, förlag, år, upplaga, sidor
    Elsevier, 2018
    Nyckelord
    Poly (methyl methacrylate), bone cement, low-modulus, In vivo, linoleic acid
    Nationell ämneskategori
    Annan materialteknik
    Forskningsämne
    Teknisk fysik med inriktning mot materialvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-349033 (URN)10.1016/j.actbio.2018.03.014 (DOI)
    Tillgänglig från: 2018-04-20 Skapad: 2018-04-20 Senast uppdaterad: 2018-05-09Bibliografiskt granskad
    3. Functional properties of low-modulus PMMA bone cements containing linoleic acid
    Öppna denna publikation i ny flik eller fönster >>Functional properties of low-modulus PMMA bone cements containing linoleic acid
    (Engelska)Ingår i: Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm)) In press
    Abstract [en]

    Spinal augmentation using rigid acrylic bone cement may facilitate the formation of additional vertebral compression fractures (VCFs) in the vicinity of the collapsed vertebrae. It has been hypothesized that the use of less stiff bone cement could reduce the occurrence of adjacent VCFs. Acrylic bone cement modified with linoleic acid (LA) has been reported as a promising low-modulus alternative. However, several key properties remain unexplored. In this study, the flexural properties and screw augmentation capacity of the LA-modified cement were evaluated. The effect of sterilization through autoclaving was assessed in terms of LA composition and cement handling properties, glass transition temperature (Tg) and quasi-static compressive mechanical properties. 

    The bending modulus, bending strength and pull-out force were, as with the compressive properties, significantly affected by the addition of LA, giving mechanical properties closer to those of vertebral trabecular bone. The maximum polymerization temperature was significantly lower for LA-modified cement (28.2 ± 0.4 °C for non-sterile and 31.1 ± 1.1 °C for sterile material) than the control cement (66.8 ± 3 °C). The setting time of the cements remained comparable, at between 20-25 minutes, but LA-modified cements could be injected over a longer period than the regular cement. Sterilized and non-sterilized LA-modified cements displayed similar injectability and mechanical properties over time. The Tgof sterilized LA-cement (78.0 ± 3.2 °C) was not statistically different from the Tgof non-sterilized LA-cement (74.7 ± 4.8 °C) but both were significantly lower than the Tgof the control cement (102.8 ± 1.3 °C). 

    In summary, a sterilization process could be used without significantly affecting the functional properties of LA-modified cement. These cements displayed excellent handling and mechanical properties that more closely match those of osteoporotic vertebral bone. They exhibited a pullout strength comparable to some ceramic bone cements, demonstrating potential for use in applications where hardware needs to be applied. 

    Nyckelord
    Acrylic bone cement, low-modulus, mechanical properties, bending, vertebroplasty, screw, pullout, sterilization
    Nationell ämneskategori
    Materialteknik
    Forskningsämne
    Teknisk fysik med inriktning mot materialvetenskap
    Identifikatorer
    urn:nbn:se:uu:diva-349057 (URN)
    Tillgänglig från: 2018-04-20 Skapad: 2018-04-20 Senast uppdaterad: 2018-04-20
    4. Compressive fatigue properties of commercially available standard and low-modulus acrylic bone cements intended for vertebroplasty
    Öppna denna publikation i ny flik eller fönster >>Compressive fatigue properties of commercially available standard and low-modulus acrylic bone cements intended for vertebroplasty
    2018 (Engelska)Ingår i: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, E-ISSN 1878-0180, Vol. 82, s. 70-76Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm)) Published
    Abstract [en]

    Vertebroplasty (VP) is a minimally invasive surgical procedure commonly used to relieve severe back pain associated with vertebral compression fractures. The poly(methyl methacrylate) bone cement used during this procedure is however presumed to facilitate the occurrence of additional fractures next to the treated vertebrae. A reason for this is believed to be the difference in stiffness between the bone cement and the surrounding trabecular bone. The use of bone cements with lower mechanical properties could therefore reduce the risk of complications post-surgery. While intensive research has been performed on the quasi-static mechanical properties of these cements, there is no data on their long-term mechanical properties. In the present study, the in vitrocompressive fatigue performance as well as quasi-static mechanical properties of two commercially available acrylic bone cements - a low-modulus cement (Resilience®) and a standard cement (F20) from the same manufacturer - were determined. The quasi-static mechanical properties of the low-modulus and standard cements after 24h of setting were in the range of other vertebroplastic cements (σ=70-75 MPa; E=1600-1900 MPa). F20 displayed similar mechanical properties over time in 37˚C phosphate buffered saline solution, while the mechanical properties of the Resilience®cement