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Seufert, V., Granath, G. & Müller, C. (2019). A meta-analysis of crop response patterns to nitrogen limitation for improved model representation. PLoS ONE, 14(10), e0223508-e0223508
Open this publication in new window or tab >>A meta-analysis of crop response patterns to nitrogen limitation for improved model representation
2019 (English)In: PLoS ONE, E-ISSN 1932-6203, Vol. 14, no 10, p. e0223508-e0223508Article in journal (Refereed) Published
Abstract [en]

The representation of carbon-nitrogen (N) interactions in global models of the natural or managed land surface remains an important knowledge gap. To improve global process-based models we require a better understanding of how N limitation affects photosynthesis and plant growth. Here we present the findings of a meta-analysis to quantitatively assess the impact of N limitation on source (photosynthate production) versus sink (photosynthate use) activity, based on 77 highly controlled experimental N availability studies on 11 crop species. Using meta-regressions, we find that it can be insufficient to represent N limitation in models merely as inhibiting carbon assimilation, because in crops complete N limitation more strongly influences leaf area expansion (-50%) than photosynthesis (-34%), while leaf starch is accumulating (+83%). Our analysis thus offers support for the hypothesis of sink limitation of photosynthesis and encourages the exploration of more sink-driven crop modelling approaches. We also show that leaf N concentration changes with N availability and that the allocation of N to Rubisco is reduced more strongly compared to other photosynthetic proteins at low N availability. Furthermore, our results suggest that different crop species show generally similar response patterns to N limitation, with the exception of leguminous crops, which respond differently. Our meta-analysis offers lessons for the improved depiction of N limitation in global terrestrial ecosystem models, as well as highlights knowledge gaps that need to be filled by future experimental studies on crop N limitation response.

Place, publisher, year, edition, pages
Public Library of Science, 2019
National Category
Botany
Identifiers
urn:nbn:se:uu:diva-397697 (URN)10.1371/journal.pone.0223508 (DOI)
Note

31622350[pmid]; PMC6797162[pmcid]; PONE-D-19-13317[PII]

Available from: 2019-11-22 Created: 2019-11-22 Last updated: 2020-01-29Bibliographically approved
Moore, P. A., Lukenbach, M. C., Thompson, D. K., Kettridge, N., Granath, G. & Waddington, J. M. (2019). Assessing the peatland hummock-hollow classification framework using high-resolution elevation models: implications for appropriate complexity ecosystem modeling. Biogeosciences, 16(18), 3491-3506
Open this publication in new window or tab >>Assessing the peatland hummock-hollow classification framework using high-resolution elevation models: implications for appropriate complexity ecosystem modeling
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2019 (English)In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 16, no 18, p. 3491-3506Article in journal (Refereed) Published
Abstract [en]

The hummock-hollow classification framework used to categorize peatland ecosystem microtopography is pervasive throughout peatland experimental designs and current peatland ecosystem modeling approaches. However, identifying what constitutes a representative hummock-hollow pair within a site and characterizing hummock-hollow variability within or between peatlands remains largely unassessed. Using structure from motion (SfM), high-resolution digital elevation models (DEMs) of hummock-hollow microtopography were used to (1) examine how much area needs to be sampled to characterize site-level microtopographic variation; and (2) examine the potential role of microtopographic shape/structure on biogeochemical fluxes using plot-level data from nine northern peatlands. To capture 95% of site-level microtopographic variability, on average, an aggregate sampling area of 32 m(2) composed of 10 randomly located plots was required. Both site(i.e. transect data) and plot-level (i.e. SfM-derived DEM) results show that microtopographic variability can be described as a fractal at the submeter scale, where contributions to total variance are very small below a 0.5 m length scale. Microtopography at the plot level was often found to be non-bimodal, as assessed using a Gaussian mixture model (GMM). Our findings suggest that the non-bimodal distribution of microtopography at the plot level may result in an undersampling of intermediate topographic positions. Extended to the modeling domain, an underrepresentation of intermediate microtopographic positions is shown to lead to potentially large flux biases over a wide range of water table positions for ecosystem processes which are non-linearly related to water and energy availability at the moss surface. Moreover, our simple modeling results suggest that much of the bias can be eliminated by representing microtopography with several classes rather than the traditional two (i.e. hummock/hollow). A range of tools examined herein can be used to easily parameterize peatland models, from GMMs used as simple transfer functions to spatially explicit fractal landscapes based on simple power-law relations between microtopographic variability and scale.

Place, publisher, year, edition, pages
COPERNICUS GESELLSCHAFT MBH, 2019
National Category
Botany
Identifiers
urn:nbn:se:uu:diva-395688 (URN)10.5194/bg-16-3491-2019 (DOI)000487709300001 ()
Available from: 2019-10-24 Created: 2019-10-24 Last updated: 2019-10-24Bibliographically approved
Singer, D., Mitchell, E. A. D., Payne, R. J., Blandenier, Q., Duckert, C., Fernandez, L. D., . . . Lara, E. (2019). Dispersal limitations and historical factors determine the biogeography of specialized terrestrial protists. Molecular Ecology, 28(12), 3089-3100
Open this publication in new window or tab >>Dispersal limitations and historical factors determine the biogeography of specialized terrestrial protists
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2019 (English)In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 28, no 12, p. 3089-3100Article in journal (Refereed) Published
Abstract [en]

Recent studies show that soil eukaryotic diversity is immense and dominated by micro-organisms. However, it is unclear to what extent the processes that shape the distribution of diversity in plants and animals also apply to micro-organisms. Major diversification events in multicellular organisms have often been attributed to long-term climatic and geological processes, but the impact of such processes on protist diversity has received much less attention as their distribution has often been believed to be largely cosmopolitan. Here, we quantified phylogeographical patterns in Hyalosphenia papilio, a large testate amoeba restricted to Holarctic Sphagnum-dominated peatlands, to test if the current distribution of its genetic diversity can be explained by historical factors or by the current distribution of suitable habitats. Phylogenetic diversity was higher in Western North America, corresponding to the inferred geographical origin of the H. papilio complex, and was lower in Eurasia despite extensive suitable habitats. These results suggest that patterns of phylogenetic diversity and distribution can be explained by the history of Holarctic Sphagnum peatland range expansions and contractions in response to Quaternary glaciations that promoted cladogenetic range evolution, rather than the contemporary distribution of suitable habitats. Species distributions were positively correlated with climatic niche breadth, suggesting that climatic tolerance is key to dispersal ability in H. papilio. This implies that, at least for large and specialized terrestrial micro-organisms, propagule dispersal is slow enough that historical processes may contribute to their diversification and phylogeographical patterns and may partly explain their very high overall diversity.

Place, publisher, year, edition, pages
WILEY, 2019
Keywords
distribution, Holarctic, Hyalosphenia papilio, phylogeography, protists, Sphagnum peatland
National Category
Evolutionary Biology
Identifiers
urn:nbn:se:uu:diva-390788 (URN)10.1111/mec.15117 (DOI)000475147100001 ()31055860 (PubMedID)
Funder
Swedish Research Council, 2015-05174
Available from: 2019-08-15 Created: 2019-08-15 Last updated: 2019-08-15Bibliographically approved
Mazziotta, A., Granath, G., Rydin, H., Bengtsson, F. & Norberg, J. (2019). Scaling functional traits to ecosystem processes: Towards a mechanistic understanding in peat mosses. Journal of Ecology, 107(2), 843-859
Open this publication in new window or tab >>Scaling functional traits to ecosystem processes: Towards a mechanistic understanding in peat mosses
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2019 (English)In: Journal of Ecology, ISSN 0022-0477, E-ISSN 1365-2745, Vol. 107, no 2, p. 843-859Article in journal (Refereed) Published
Abstract [en]

The role of trait trade-offs and environmental filtering in explaining the variability in functional traits and ecosystem processes has received considerable attention for vascular plants but less so for bryophytes. Thus, we do not know whether the same forces also shape the phenotypic variability of bryophytes. Here, we assess how environmental gradients and trade-offs shape functional traits and subsequently ecosystem processes for peat mosses (Sphagnum), a globally important plant genus for carbon accumulation. We used piecewise Structural Equation Modeling (SEM) to understand how environmental gradients influence vital processes across levels of biological organization. We gathered data on functional traits for 15 globally important Sphagnum species covering a wide range of ecological preferences. Phenotypes lie along well-established axes of the plant economic spectrum characterizing trade-offs between vital physiological functions. Using SEM, we clarified the mechanisms of trait covariation and scaling to ecosystem processes. We tested whether peat mosses, like vascular plants, constrain trait variability between a fast turnover strategy based on resource acquisition via fast traits and processes, and a strategy of resource conservation, via slow traits and processes. We parameterized a process-based model estimating ecosystem processes linking environmental drivers with architectural and functional traits. In our SEM approach the amount of variance explained varied substantially (0.29 <= R-2 <= 0.82) among traits and processes in Sphagnum, and the model could predict some of them with high to intermediate accuracy for an independent dataset. R-2 variability was mainly explained by traits and species identity, and poorly by environmental filtering. Some Sphagnum species avoid the stress caused by periodic desiccation in hollows via resource acquisition based on fast photosynthesis and growth, while other species are adapted to grow high above the water-table on hummocks by slow physiological traits and processes to conserve resources. Synthesis.We contribute to a unified theory generating individual fitness, canopy dynamics and ecosystem processes from trait variation. As for vascular plants, the functional traits in the Sphagnum economic spectrum are linked into an integrated phenotypic network partly filtered by the environment and shaped by trade-offs in resource acquisition and conservation.

Place, publisher, year, edition, pages
WILEY, 2019
Keywords
bryophytes, ecosystem processes, peatlands, piecewise SEM, plant development and life-history traits, plant economic spectrum, Sphagnum, Structural Equation Modeling
National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-378633 (URN)10.1111/1365-2745.13110 (DOI)000458616400029 ()
Funder
Swedish Research Council
Available from: 2019-03-07 Created: 2019-03-07 Last updated: 2019-03-07Bibliographically approved
Ramberg, E., Strengbom, J. & Granath, G. (2018). Coordination through databases can improve prescribed burning as a conservation tool to promote forest biodiversity. Ambio, 47(3), 298-306
Open this publication in new window or tab >>Coordination through databases can improve prescribed burning as a conservation tool to promote forest biodiversity
2018 (English)In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 47, no 3, p. 298-306Article in journal (Refereed) Published
Abstract [en]

Prescribed fires are a common nature conservation practice. They are executed by several parties with limited coordination among them, and little consideration for wildfire occurrences and habitat requirements of fire-dependent species. Here, we gathered data on prescribed fires and wildfires in Sweden during 2011-2015 to (i) evaluate the importance and spatial extent of prescribed fires compared to wildfires and (ii) illustrate how a database can be used as a management tool for prescribed fires. We found that on average only 0.006% (prescribed 65%, wildfires 35%) of the Swedish forest burns per year, with 58% of the prescribed fires occurring on clearcuts. Also, both wildfires and prescribed fires seem to be important for the survival of fire-dependent species. A national fire database would simplify coordination and make planning and evaluation of prescribed fires more efficient. We propose an adaptive management strategy to improve the outcome of prescribed fires.

Keywords
Boreal, Fire-dependent species, Forest management, Geranium lanuginosum, Prescribed burning, Stephanopachys substriatus
National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-373255 (URN)10.1007/s13280-017-0987-6 (DOI)000427846800004 ()29127668 (PubMedID)
Available from: 2019-01-11 Created: 2019-01-11 Last updated: 2019-01-11Bibliographically approved
Granath, G., Rydin, H., Baltzer, J. L., Bengtsson, F., Boncek, N., Bragazza, L., . . . Rice, S. K. (2018). Environmental and taxonomic controls of carbon and oxygen stable isotope composition in Sphagnum across broad climatic and geographic ranges. Biogeosciences, 15(16), 5189-5202
Open this publication in new window or tab >>Environmental and taxonomic controls of carbon and oxygen stable isotope composition in Sphagnum across broad climatic and geographic ranges
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2018 (English)In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 15, no 16, p. 5189-5202Article in journal (Refereed) Published
Abstract [en]

Rain-fed peatlands are dominated by peat mosses (Sphagnum sp.), which for their growth depend on nutrients, water and CO2 uptake from the atmosphere. As the isotopic composition of carbon (C-12(,)13) and oxygen (O-16(,)18) of these Sphagnum mosses are affected by environmental conditions, Sphagnum tissue accumulated in peat constitutes a potential long-term archive that can be used for climate reconstruction. However, there is inadequate understanding of how isotope values are influenced by environmental conditions, which restricts their current use as environmental and palaeoenvironmental indicators. Here we tested (i) to what extent C and O isotopic variation in living tissue of Sphagnum is speciesspecific and associated with local hydrological gradients, climatic gradients (evapotranspiration, temperature, precipitation) and elevation; (ii) whether the C isotopic signature can be a proxy for net primary productivity (NPP) of Sphagnum; and (iii) to what extent Sphagnum tissue delta O-18 tracks the delta O-18 isotope signature of precipitation. In total, we analysed 337 samples from 93 sites across North America and Eurasia us ing two important peat-forming Sphagnum species (S. magellanicum, S. fuscum) common to the Holarctic realm. There were differences in delta C-13 values between species. For S. magellanicum delta C-13 decreased with increasing height above the water table (HWT, R-2 = 17 %) and was positively correlated to productivity (R-2 = 7 %). Together these two variables explained 46 % of the between-site variation in delta C-13 values. For S. fuscum, productivity was the only significant predictor of delta C-13 but had low explanatory power (total R-2 = 6 %). For delta O-18 values, approximately 90 % of the variation was found between sites. Globally modelled annual delta O-18 values in precipitation explained 69 % of the between-site variation in tissue delta O-18. S. magellanicum showed lower delta O-18 enrichment than S. fuscum (-0.83 %0 lower). Elevation and climatic variables were weak predictors of tissue delta O-18 values after controlling for delta O-18 values of the precipitation. To summarize, our study provides evidence for (a) good predictability of tissue delta O-18 values from modelled annual delta O-18 values in precipitation, and (b) the possibility of relating tissue delta C-13 values to HWT and NPP, but this appears to be species-dependent. These results suggest that isotope composition can be used on a large scale for climatic reconstructions but that such models should be species-specific.

National Category
Geosciences, Multidisciplinary
Identifiers
urn:nbn:se:uu:diva-364191 (URN)10.5194/bg-15-5189-2018 (DOI)000443077000002 ()
Funder
Swedish Research Council, 2015-05174
Available from: 2018-10-30 Created: 2018-10-30 Last updated: 2019-02-01Bibliographically approved
Weston, D. J., Turetsky, M. R., Johnson, M. G., Granath, G., Lindo, Z., Belyea, L. R., . . . Shaw, A. J. (2018). The Sphagnome Project: enabling ecological and evolutionary insights through a genus-level sequencing project. New Phytologist, 217(1), 16-25
Open this publication in new window or tab >>The Sphagnome Project: enabling ecological and evolutionary insights through a genus-level sequencing project
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2018 (English)In: New Phytologist, ISSN 0028-646X, E-ISSN 1469-8137, Vol. 217, no 1, p. 16-25Article in journal, Editorial material (Other academic) Published
Abstract [en]

Considerable progress has been made in ecological and evolutionary genetics with studies demonstrating how genes underlying plant and microbial traits can influence adaptation and even 'extend' to influence community structure and ecosystem level processes. Progress in this area is limited to model systems with deep genetic and genomic resources that often have negligible ecological impact or interest. Thus, important linkages between genetic adaptations and their consequences at organismal and ecological scales are often lacking. Here we introduce the Sphagnome Project, which incorporates genomics into a long-running history of Sphagnum research that has documented unparalleled contributions to peatland ecology, carbon sequestration, biogeochemistry, microbiome research, niche construction, and ecosystem engineering. The Sphagnome Project encompasses a genus-level sequencing effort that represents a new type of model system driven not only by genetic tractability, but by ecologically relevant questions and hypotheses.

Keywords
ecological genomics, ecosystem engineering, evolutionary genetics, genome sequencing, niche construction, peatlands, Sphagnome, Sphagnum
National Category
Genetics and Breeding in Agricultural Sciences Ecology
Identifiers
urn:nbn:se:uu:diva-351606 (URN)10.1111/nph.14860 (DOI)000426309500004 ()29076547 (PubMedID)
Available from: 2018-05-29 Created: 2018-05-29 Last updated: 2019-02-01Bibliographically approved
Granath, G., Kouki, J., Johnson, S., Heikkala, O., Rodríguez, A. & Strengbom, J. (2018). Trade-offs in berry production and biodiversity under prescribed burning and retention regimes in boreal forests [Letter to the editor]. Journal of Applied Ecology, 55(4), 1658-1667
Open this publication in new window or tab >>Trade-offs in berry production and biodiversity under prescribed burning and retention regimes in boreal forests
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2018 (English)In: Journal of Applied Ecology, ISSN 0021-8901, E-ISSN 1365-2664, Vol. 55, no 4, p. 1658-1667Article in journal, Letter (Other academic) Published
Abstract [en]

Green tree retention and prescribed burning are the practices used to mitigate negative effects of boreal forestry. Beside their effects on biodiversity, these practices should also promote non-timber forest products (NTFPs). We assessed: (1) how prescribed burning and tree retention influence NTFPs by examining the production of bilberry, Vaccinium myrtillus and cowberry, Vaccinium vitis-idaea; (2) if there are synergies or trade-offs in the delivery of these NTFPs in relation to the delivery of species richness, focusing on five groups of forest-dwelling species. We used a long-term experiment located in eastern Finland, with three different harvesting treatments: clear-cut logging, logging with retention patches and unlogged, which were combined with or without prescribed burning. Eleven years after the treatment application, we scored plant cover and berry production in different microhabitats within these treatments, while species richness data for five species groups (ground layer lichens and bryophytes, vascular plants, saproxylic beetles, pollinators?here bees and hoverflies) were collected at the stand level. Logging favoured cowberry production, particularly for plants growing in the vicinity of stumps. Logging was detrimental for cover and berry production of bilberry. Retention mitigated these negative effects slightly, but cover and berry production were still substantially lower compared to unlogged forests. Prescribed burning increased the cowberry production in retention patches and in unlogged forest. Bilberry production decreased with burning, except in unlogged forest where the effect was neutral. No single management treatment simultaneously favoured all values?NTFPs and richness?and trade-offs among values were common. Only bilberry production and beetle diversity were higher under retention forestry, or in unlogged stands, compared to logged stands. Prescribed burning favoured many values when performed in combination with retention forestry, or in unlogged stands, but different treatment combinations favoured different species groups. Synthesis and applications. Our results demonstrate that widely applied conservation practices in managed boreal forests are unlikely to benefit all ecosystem values everywhere. If high multifunctionality is desired, managing at a landscape scale, countering the local trade-offs among values, may be more appropriate than the stand-scale conservation practices commonly practiced today.

Keywords
berry production, boreal forests, ecosystem service forestry, landscape management, landscape scale, multifunctionality, non-timber forest products, prescribed burns, retention forestry, species richness
National Category
Ecology
Research subject
Biology
Identifiers
urn:nbn:se:uu:diva-397698 (URN)10.1111/1365-2664.13098 (DOI)000434970200010 ()
Available from: 2019-11-22 Created: 2019-11-22 Last updated: 2019-11-26Bibliographically approved
Vicari, M., Puentes, A., Granath, G., Georgeff, J., Strathdee, F. & Bazely, D. R. (2018). Unpacking multi-trophic herbivore-grass-endophyte interactions: feedbacks across different scales in vegetation responses to Soay sheep herbivory. The Science of Nature: Naturwissenschaften, 105(11-12), Article ID 66.
Open this publication in new window or tab >>Unpacking multi-trophic herbivore-grass-endophyte interactions: feedbacks across different scales in vegetation responses to Soay sheep herbivory
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2018 (English)In: The Science of Nature: Naturwissenschaften, ISSN 0028-1042, E-ISSN 1432-1904, Vol. 105, no 11-12, article id 66Article in journal (Refereed) Published
Abstract [en]

Grazing can induce changes in both plant productivity and nutritional quality, which may subsequently influence herbivore carrying capacity. While research on Soay sheep (Ovis aries L.) dynamics on Hirta Island in the St. Kilda archipelago has elucidated the complexity of population drivers, including parasites, the role of herbivore-generated feedbacks as an intrinsic regulating factor remains unclear. The sheep lack large predators and every 3-9years undergo population crashes (overcompensatory mortality). We investigated the effects of grazing on (1) sward productivity and (2) quality (toxicity) of the primary forage species, red fescue (Festuca rubra L.), which is highly infected by an alkaloid-synthesizing fungal endophyte. Grazing had a negative impact on both forage quantity and quality. At higher sheep densities, impacts on sward growth were magnified, resulting in a nonlinear relationship with plant productivity. Simultaneously, endophyte hyphal load (and by inference, toxicity) peaked close to the time of a crash. A greenhouse experiment showed that alkaloid concentration in F. rubra increased in response to artificial defoliation. We conclude that at high sheep densities, grazing-mediated reductions in productivity, together with sustained alkaloid production, are likely to influence sheep dynamics. Future research should consider the interactive effects of forage toxicity, quantity, and nutritional content.

Keywords
Aboveground net primary production (ANPP), Epichloe festucae, Grazing optimization, Herbivore irruptions, Inducible defenses, Plant demography
National Category
Ecology
Identifiers
urn:nbn:se:uu:diva-371041 (URN)10.1007/s00114-018-1590-9 (DOI)000450866600001 ()30460621 (PubMedID)
Available from: 2019-01-07 Created: 2019-01-07 Last updated: 2019-02-01Bibliographically approved
Johnson, M. G., Granath, G., Tahvanainen, T., Pouliot, R., Stenoien, H. K., Rochefort, L., . . . Shaw, A. J. (2015). Evolution of niche preference in Sphagnum peat mosses. Evolution, 69(1), 90-103
Open this publication in new window or tab >>Evolution of niche preference in Sphagnum peat mosses
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2015 (English)In: Evolution, ISSN 0014-3820, E-ISSN 1558-5646, Vol. 69, no 1, p. 90-103Article in journal (Refereed) Published
Abstract [en]

Peat mosses (Sphagnum) are ecosystem engineersspecies in boreal peatlands simultaneously create and inhabit narrow habitat preferences along two microhabitat gradients: an ionic gradient and a hydrological hummock-hollow gradient. In this article, we demonstrate the connections between microhabitat preference and phylogeny in Sphagnum. Using a dataset of 39 species of Sphagnum, with an 18-locus DNA alignment and an ecological dataset encompassing three large published studies, we tested for phylogenetic signal and within-genus changes in evolutionary rate of eight niche descriptors and two multivariate niche gradients. We find little to no evidence for phylogenetic signal in most component descriptors of the ionic gradient, but interspecific variation along the hummock-hollow gradient shows considerable phylogenetic signal. We find support for a change in the rate of niche evolution within the genusthe hummock-forming subgenus Acutifolia has evolved along the multivariate hummock-hollow gradient faster than the hollow-inhabiting subgenus Cuspidata. Because peat mosses themselves create some of the ecological gradients constituting their own habitats, the classic microtopography of Sphagnum-dominated peatlands is maintained by evolutionary constraints and the biological properties of related Sphagnum species. The patterns of phylogenetic signal observed here will instruct future study on the role of functional traits in peatland growth and reconstruction.

Keywords
Bryophyte, comparative methods, peatland ecology, phylogenetic signal
National Category
Biological Sciences
Identifiers
urn:nbn:se:uu:diva-243667 (URN)10.1111/evo.12547 (DOI)000347462800007 ()25319183 (PubMedID)
Available from: 2015-02-20 Created: 2015-02-11 Last updated: 2019-02-01Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-3632-9102

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