uu.seUppsala universitets publikationer
Ändra sökning
Avgränsa sökresultatet
1234567 1 - 50 av 5410
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 1.
    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.

  • 2.
    Zafari, Afshin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Avdelningen för beräkningsvetenskap. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Matematisk-datavetenskapliga sektionen, Institutionen för informationsteknologi, Tillämpad beräkningsvetenskap.
    Advances in Task-Based Parallel Programming for Distributed Memory Architectures2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    It has become common knowledge that parallel programming is needed for scientific applications, particularly for running large scale simulations. Different programming models are introduced for simplifying parallel programming, while enabling an application to use the full computational capacity of the hardware. In task-based programming, all the variables in the program are abstractly viewed as data. Parallelism is provided by partitioning the data. A task is a collection of operations performed on input data to generate output data. In distributed memory environments, the data is distributed over the computational nodes (or processes), and is communicated when a task needs remote data.

    This thesis discusses advanced techniques in distributed task-based parallel programming, implemented in the DuctTeip software library. DuctTeip uses MPI (Message Passing Interface) for asynchronous inter-process communication and Pthreads for shared memory parallelization within the processes. The data dependencies that determine which subsets of tasks can be executed in parallel are extracted from information about the data accesses (input or output) of the tasks. A versioning system is used internally to represent the task-data dependencies efficiently. A hierarchical partitioning of tasks and data allows for independent optimization of the size of computational tasks and the size of communicated data. A data listener technique is used to manage communication efficiently.

    DuctTeip provides an algorithm independent dynamic load balancing functionality. Redistributing tasks from busy processes to idle processes dynamically can provide an overall shorter execution time. A random search method with high probability of success is employed for locating idle/busy nodes.

    The advantage of the abstract view of tasks and data is exploited in a unified programming interface, which provides a standard for task-based frameworks to decouple framework development from application development. The interface can be used for collaboration between different frameworks in running an application program efficiently on different hardware.

    To evaluate the DuctTeip programming model, applications such as Cholesky factorization, a time-dependent PDE solver for the shallow water equations, and the fast multipole method have been implemented using DuctTeip. Experiments show that DuctTeip provides both scalability and performance. Comparisons with similar frameworks such as StarPU, OmpSs, and PaRSEC show competitive results.

    Delarbeten
    1. Programming models based on data versioning for dependency-aware task-based parallelisation
    Öppna denna publikation i ny flik eller fönster >>Programming models based on data versioning for dependency-aware task-based parallelisation
    2012 (Engelska)Ingår i: Proc. 15th International Conference on Computational Science and Engineering, Los Alamitos, CA: IEEE Computer Society, 2012, s. 275-280Konferensbidrag, Publicerat paper (Refereegranskat)
    Ort, förlag, år, upplaga, sidor
    Los Alamitos, CA: IEEE Computer Society, 2012
    Nationell ämneskategori
    Programvaruteknik
    Identifikatorer
    urn:nbn:se:uu:diva-187446 (URN)10.1109/ICCSE.2012.45 (DOI)000317475000038 ()978-1-4673-5165-2 (ISBN)
    Konferens
    CSE 2012
    Projekt
    eSSENCEUPMARC
    Tillgänglig från: 2013-01-24 Skapad: 2012-12-06 Senast uppdaterad: 2018-01-16Bibliografiskt granskad
    2. DuctTeip: An efficient programming model for distributed task based parallel computing
    Öppna denna publikation i ny flik eller fönster >>DuctTeip: An efficient programming model for distributed task based parallel computing
    2018 (Engelska)Ingår i: Computing Research Repository, nr 1801.03578Artikel i tidskrift (Övrigt vetenskapligt) Submitted
    Nationell ämneskategori
    Programvaruteknik
    Identifikatorer
    urn:nbn:se:uu:diva-338832 (URN)
    Projekt
    UPMARCeSSENCE
    Tillgänglig från: 2018-01-10 Skapad: 2018-01-14 Senast uppdaterad: 2018-04-18Bibliografiskt granskad
    3. TaskUniVerse: A Task-Based Unified Interface for Versatile Parallel Execution
    Öppna denna publikation i ny flik eller fönster >>TaskUniVerse: A Task-Based Unified Interface for Versatile Parallel Execution
    2018 (Engelska)Ingår i: Parallel Processing and Applied Mathematics: Part I, Springer, 2018, s. 169-184Konferensbidrag, Publicerat paper (Refereegranskat)
    Ort, förlag, år, upplaga, sidor
    Springer, 2018
    Serie
    Lecture Notes in Computer Science ; 10777
    Nationell ämneskategori
    Programvaruteknik
    Identifikatorer
    urn:nbn:se:uu:diva-338836 (URN)10.1007/978-3-319-78024-5_16 (DOI)978-3-319-78023-8 (ISBN)
    Konferens
    PPAM 2017
    Projekt
    eSSENCE
    Tillgänglig från: 2018-03-23 Skapad: 2018-01-14 Senast uppdaterad: 2018-03-26Bibliografiskt granskad
    4. Task parallel implementation of a solver for electromagnetic scattering problems
    Öppna denna publikation i ny flik eller fönster >>Task parallel implementation of a solver for electromagnetic scattering problems
    Visa övriga...
    2018 (Engelska)Ingår i: Computing Research Repository, nr 1801.03589Artikel i tidskrift (Övrigt vetenskapligt) Submitted
    Nationell ämneskategori
    Datavetenskap (datalogi) Beräkningsmatematik
    Identifikatorer
    urn:nbn:se:uu:diva-338833 (URN)
    Projekt
    eSSENCE
    Tillgänglig från: 2018-01-11 Skapad: 2018-01-14 Senast uppdaterad: 2018-04-18Bibliografiskt granskad
    5. Distributed dynamic load balancing for task parallel programming
    Öppna denna publikation i ny flik eller fönster >>Distributed dynamic load balancing for task parallel programming
    2018 (Engelska)Ingår i: Computing Research Repository, nr 1801.04582Artikel i tidskrift (Övrigt vetenskapligt) Submitted
    Nationell ämneskategori
    Datavetenskap (datalogi)
    Identifikatorer
    urn:nbn:se:uu:diva-338835 (URN)
    Projekt
    UPMARCeSSENCE
    Tillgänglig från: 2018-01-14 Skapad: 2018-01-14 Senast uppdaterad: 2018-04-18Bibliografiskt granskad
  • 3.
    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
  • 4.
    Sakka, Laura Stavroula
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Affective responses to music in depressed individuals: Aesthetic judgments, emotions, and the impact of music-evoked autobiographical memories2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Music’s powerful influence on our affective states is often utilized in everyday life for emotion regulation and in music-therapeutic interventions against depression. Given this ability of music to influence emotions and symptoms in depressed people, it appears imperative to understand how these individuals affectively respond to music. The primary aim of this thesis is to explore whether depressed individuals have distinct affective responses to music, in terms of aesthetic judgments, emotional reactions, and emotion regulation. Furthermore, the thesis aims to provide possible explanations for such differences, in terms of underlying psychological processes (e.g., emotion-induction mechanisms) and depressive attributes (e.g., cognitive biases). Study I involves a music listening experiment exploring the relationship between depression and aesthetic judgments in music. Findings indicate that depression is associated with higher ratings of aesthetic judgment, accompanied by an enhanced reliance on the expressivity criterion. However, this relationship is not accompanied by an association between depression and the Openness to Experience personality factor. Study II investigates emotion regulation with music in depressed individuals, by means of a survey. The study features a novel conceptual framework for studying emotion regulation with music, grounded on the established process model of emotion regulation (Gross, 2008) in combination with the music-specific multi-level GSTM approach (van Goethem & Sloboda, 2011). Results indicate that depressed individuals do not differ from controls in their “active” emotional responding (i.e., emotion regulation) to music. Study III features an experiment comparing depressed to controls’ “passive” emotional responses (i.e., emotional reactions) to musical stimuli designed to activate specific mechanisms (i.e., Brain stem reflex, Contagion, and Episodic memory). Findings suggest that differences in emotional reactions occur with respect to episodic memory, potentially due to cognitive biases. Finally, Study IV follows up on these results and investigates the valence and specificity of music-evoked memories in depressed individuals. The study finds that depressed participants’ memories are negatively biased, but do not differ from controls’ in level of specificity. Together, the findings of this thesis suggest that music listening may have a dual potential for depressed individuals, functioning both as a beneficial resource for alleviating depressive symptoms (due to, e.g., elevated aesthetic appreciation of music) and as a contributing factor to depressive mood (due to, e.g., negatively biased memories).

    Delarbeten
    1. No accounting for taste? Idiographic models of aesthetic judgment in music
    Öppna denna publikation i ny flik eller fönster >>No accounting for taste? Idiographic models of aesthetic judgment in music
    2016 (Engelska)Ingår i: Psychology of Aesthetics, Creativity, and the Arts, ISSN 1931-3896, E-ISSN 1931-390X, Vol. 10, nr 2, s. 157-170Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Music is commonly regarded as one of the fine arts, but aesthetic responses to music are still poorly understood. In this study, we investigated aesthetic judgments of music by using the tools of judgment analysis. The aim was to shed some light on the psychological process through which listeners use a set of subjective and differentially weighted criteria to assign aesthetic value to pieces of music. We used a stratified random sampling procedure to select 72 pieces of music from 12 genres. The pieces were divided across 2 groups of participants (N = 44), who rated each piece with regard to 7 aesthetic criteria (e.g., beauty, originality, expressivity) and overall aesthetic value. Both individual ("idiographic") and averaged ("nomothetic") multiple regression analyses were conducted on the listeners' judgments. The results revealed that (a) linear models provided a good fit to the listeners' aesthetic judgments (mean variance accounted for 76%), suggesting that the process is systematic and mainly additive; (b) some criteria (e.g., originality, skill) made a larger contribution to prediction than others overall; (c) there were wide individual differences between listeners concerning which criteria they used; (d) a nomothetic regression model did not adequately reflect the distinct judgment policies of individual listeners; (e) the trait openness to experience was not correlated with judgments of aesthetic value; and (f) listeners who scored high on the Beck Depression Inventory generally provided higher ratings of aesthetic value (r = .40) than listeners who scored low.

    Nyckelord
    aesthetics; judgment; modeling; music; preference
    Nationell ämneskategori
    Psykologi
    Identifikatorer
    urn:nbn:se:uu:diva-269913 (URN)10.1037/aca0000034 (DOI)000379783500005 ()
    Forskningsfinansiär
    Vetenskapsrådet, 421-2010-2129
    Tillgänglig från: 2015-12-18 Skapad: 2015-12-18 Senast uppdaterad: 2018-01-19Bibliografiskt granskad
    2. Emotion regulation with music in depressed and non-depressed individuals: goals, strategies, and mechanisms
    Öppna denna publikation i ny flik eller fönster >>Emotion regulation with music in depressed and non-depressed individuals: goals, strategies, and mechanisms
    2018 (Engelska)Ingår i: Music & Science, ISSN 20592043, Vol. 1, s. 1-12Artikel i tidskrift (Refereegranskat) Published
    Ort, förlag, år, upplaga, sidor
    Sage Publications, 2018
    Nyckelord
    depression, emotion regulation, mechanisms, music listening, strategies
    Nationell ämneskategori
    Psykologi
    Identifikatorer
    urn:nbn:se:uu:diva-339558 (URN)
    Tillgänglig från: 2018-01-19 Skapad: 2018-01-19 Senast uppdaterad: 2018-03-14Bibliografiskt granskad
    3. Emotional reactions to music in depressed individuals
    Öppna denna publikation i ny flik eller fönster >>Emotional reactions to music in depressed individuals
    2017 (Engelska)Ingår i: Psychology of Music, ISSN 0305-7356, E-ISSN 1741-3087Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Music is often used to alleviate depression, an affective disorder. Yet, little is known about how listeners suffering from depression respond emotionally to music. The goal of this study was to investigate whether listeners show different patterns of emotional reactions to music depending on level of depression. In previous research, depression has been linked with negative biases in cognitive processes such as memory and attention. Here we indirectly investigated whether such biases may also influence psychological mechanisms involved in the arousal of emotions during musical experiences. Seventy-seven listeners (19?65 years old) took part in an experiment which compared depressed individuals with non-depressed controls. The participants listened to music stimuli designed to target specific induction mechanisms (brain stem reflex, contagion, episodic memory), and were asked to rate felt emotions. Based on previous studies on cognitive bias, we made predictions about how depression would affect reactions to each stimulus. The predictions received partial support: depressed listeners reported significantly lower levels of happiness in the memory condition and non-significantly higher levels of anxiety in the brain stem condition, than did controls. Conversely, no difference in reported sadness was found in the contagion condition. Observed differences were mainly attributable to the severely depressed listeners.

    Ort, förlag, år, upplaga, sidor
    SAGE Publications Ltd, 2017
    Nationell ämneskategori
    Psykologi
    Identifikatorer
    urn:nbn:se:uu:diva-331331 (URN)10.1177/0305735617730425 (DOI)
    Konferens
    2017/10/12
    Tillgänglig från: 2017-10-12 Skapad: 2017-10-12 Senast uppdaterad: 2018-01-19
    4. Music-evoked episodic autobiographical memories in depressed individuals: Evidence of a negative cognitive bias.
    Öppna denna publikation i ny flik eller fönster >>Music-evoked episodic autobiographical memories in depressed individuals: Evidence of a negative cognitive bias.
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Nationell ämneskategori
    Psykologi
    Identifikatorer
    urn:nbn:se:uu:diva-339559 (URN)
    Tillgänglig från: 2018-01-19 Skapad: 2018-01-19 Senast uppdaterad: 2018-01-19
  • 5.
    Nordin, Kristin
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Institutionen för psykologi.
    Aging Along the Hippocampal Axis: Structure, Function and Whole-brain Connections in Association with Memory2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Hippocampus-dependent functions display marked reductions in older age, an observation that has led to the extensive study of age effects on hippocampal properties. Even though research indicates that the hippocampus is structurally and functionally heterogeneous along its longitudinal axis, its anterior and posterior regions differentially supporting episodic and spatial memory representations, few studies explicitly consider age effects in relation to axis. Relatedly, as men and women commonly differ in episodic and spatial memory performance, and sometimes also in rates of age-related hippocampal atrophy, sex could be a potential modifier of age effects. The aim of this thesis was therefore to assess age effects on the hippocampus and its role in episodic and spatial memory across young (20-35 years), middle-aged (40-50 years) and older (60-70 years) adults, adopting a longitudinal-axis approach while considering interactions with sex. Study I evaluated hippocampal volume and activation in relation to associative memory across middle-aged and older adults. Age differences in associative memory were largest in men and paralleled by smaller volumes and less activation in the anterior hippocampus. Study II assessed hippocampus-dependent network-like organization of gray matter by measures of structural whole-brain covariance. The anterior and posterior hippocampus showed shared and distinct patterns of covariance, which were qualitatively comparable across age groups. However, participants’ expression of these patterns decreased as a function of age, comparably for men and women, and showed significant associations with episodic memory. Study III investigated age effects on resting-state functional connectivity and demonstrated that both the anterior and posterior hippocampus decreased in connectivity with several brain regions across middle-aged and older adults. Memory was only associated with age-related connectivity of the posterior hippocampus: episodic memory negatively with connectivity increasing as a function of age, and spatial memory positively with connectivity that decreased. These studies demonstrate distinct effects of age on the anterior and posterior hippocampus, and show that age-related decline of these regions differentially relates to episodic and spatial memory. Overall, findings highlight the importance of explicitly considering the heterogeneity of the hippocampal axis in the assessment of its role in age-related memory decline.

    Delarbeten
    1. Overlapping effects of age on associative memory and the anterior hippocampus from middle to older age
    Öppna denna publikation i ny flik eller fönster >>Overlapping effects of age on associative memory and the anterior hippocampus from middle to older age
    2017 (Engelska)Ingår i: Behavioural Brain Research, ISSN 0166-4328, E-ISSN 1872-7549, Vol. 317, s. 350-359Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The anterior hippocampus has been implicated in associative memory, and along with hippocampal volume, this type of memory declines with age. However, few cross-sectional studies include middle-aged samples, making it unclear at what point these age-related changes occur. In addition, although men and women have been shown to differ in associative memory and rates of age-related hippocampal atrophy, sex-differences in aging are rarely studied. To address these issues, we assessed memory for word-pairs, hippocampal volume and activation during encoding and retrieval, across middle-aged (n=39) and older (n=44) participants, specifically in relation to sex. Older adults showed significantly poorer associative memory compared to middle-aged adults, paralleled by smaller anterior hippocampi and less activation during successful retrieval. The age-by-sex interaction observed in memory performance was also mirrored in the volume and activation of the hippocampus, indicating more pronounced age-effects in men as compared to women. These results indicate a specific role of the anterior hippocampus in verbal associative memory and suggest they both decline between middle-age and older age.

    Nyckelord
    Aging, Episodic memory, Event-related activation, fMRI, Sex, Voxel-based morphometry
    Nationell ämneskategori
    Neurologi
    Identifikatorer
    urn:nbn:se:uu:diva-305754 (URN)10.1016/j.bbr.2016.10.002 (DOI)000389086700038 ()27713000 (PubMedID)
    Forskningsfinansiär
    Vetenskapsrådet, VR 2011-1943
    Tillgänglig från: 2016-10-21 Skapad: 2016-10-21 Senast uppdaterad: 2018-04-17Bibliografiskt granskad
    2. Structural whole-brain covariance of the anterior and posterior hippocampus: Associations with age and memory
    Öppna denna publikation i ny flik eller fönster >>Structural whole-brain covariance of the anterior and posterior hippocampus: Associations with age and memory
    Visa övriga...
    2018 (Engelska)Ingår i: Hippocampus, ISSN 1050-9631, E-ISSN 1098-1063, Vol. 28, nr 2, s. 151-163Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The hippocampus (HC) interacts with distributed brain regions to support memory and shows significant volume reductions in aging, but little is known about age effects on hippocampal whole-brain structural covariance. It is also unclear whether the anterior and posterior HC show similar or distinct patterns of whole-brain covariance and to what extent these are related to memory functions organized along the hippocampal longitudinal axis. Using the multivariate approach partial least squares, we assessed structural whole-brain covariance of the HC in addition to regional volume, in young, middle-aged and older adults (n = 221), and assessed associations with episodic and spatial memory. Based on findings of sex differences in both memory and brain aging, we further considered sex as a potential modulating factor of age effects. There were two main covariance patterns: one capturing common anterior and posterior covariance, and one differentiating the two regions by capturing anterior-specific covariance only. These patterns were differentially related to associative memory while unrelated to measures of single-item memory and spatial memory. Although patterns were qualitatively comparable across age groups, participants' expression of both patterns decreased with age, independently of sex. The results suggest that the organization of hippocampal structural whole-brain covariance remains stable across age, but that the integrity of these networks decreases as the brain undergoes age-related alterations.

    Nyckelord
    aging, episodic memory, longitudinal axis, sex, spatial memory
    Nationell ämneskategori
    Neurologi
    Identifikatorer
    urn:nbn:se:uu:diva-335505 (URN)10.1002/hipo.22817 (DOI)29171897 (PubMedID)
    Tillgänglig från: 2017-12-06 Skapad: 2017-12-06 Senast uppdaterad: 2018-05-09Bibliografiskt granskad
    3. Age-related hippocampal resting-state connectivity shows axis-dependent associations with memory
    Öppna denna publikation i ny flik eller fönster >>Age-related hippocampal resting-state connectivity shows axis-dependent associations with memory
    Visa övriga...
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Functional connectivity across large-scale brain networks alters in older age and changes are often associated with memory decline. Studies assessing hippocampal resting-state functional connectivity (rsFC), however, rarely consider the anterior and posterior hippocampus separately, although evidence suggests they are part of two distinct networks differentially supporting memory. While only a limited number of studies have considered age effects on axis-related hippocampal connectivity, findings suggest that rsFC of the two regions display differential effects of age. Reports on the link between such effects and memory are however inconclusive, and previous findings mainly concern episodic memory, ignoring spatial memory also dependent on the hippocampus. Here, we therefore assessed age effects on axis-related hippocampal rsFC, accounting for associations with both episodic and spatial memory in young, middle-aged and older adults (n=194). The anterior and posterior hippocampus showed different age-related decreases in connectivity assessed across middle and older age, but common to the regions was a decreased coupling with the medial orbitofrontal cortex. Only connectivity between the posterior hippocampus and the lingual gyrus increased as a function of age, displaying negative associations with episodic memory. In contrast, the region’s connectivity with the insula, decreasing with age, was positively related to spatial memory. Consistent with previous reports, our findings indicate that hippocampal rsFC vary with age in an axis-dependent manner, and further add to the knowledge on this differentiation’s relevance to memory by showing that age-related rsFC of the anterior and posterior hippocampus is differentially associated with episodic and spatial memory.

    Nyckelord
    Aging, Episodic Memory, Hippocampus, Longitudinal axis, Sex, Spatial Memory
    Nationell ämneskategori
    Psykologi
    Identifikatorer
    urn:nbn:se:uu:diva-348685 (URN)
    Tillgänglig från: 2018-04-17 Skapad: 2018-04-17 Senast uppdaterad: 2018-04-17