136 research outputs found
Plant’s gypsum affinity shapes responses to specific edaphic constraints without limiting responses to other general constraints
Aims: Harsh edaphic environments harbor species with different soil affinities. Plant’s responses to specific edaphic constraints may be compromised against responses to prevalent stresses shared with other semi-arid environments. We expect that species with high edaphic affinity may show traits to overcome harsh soil properties, while species with low affinity may respond to environmental constraints shared with arid environments. Methods: We quantified the edaphic affinity of 12 plant species co-occurring in gypsum outcrops and measured traits related to plant responses to specific gypsum constraints (rooting and water uptake depth, foliar accumulation of Ca, S and Mg), and traits related to common constraints of arid environments (water use efficiency, macronutrients foliar content). Results: Plants in gypsum outcrops differed in their strategies to face edaphic limitations. A phylogenetic informed PCA segregated species based on their foliar Ca and S accumulation and greater water uptake depths, associated with plant responses to specific gypsum limitations. Species’ gypsum affinity explained this segregation, but traits related to water or nutrient use efficiency did not contribute substantially to this axis. Conclusions: Plant’s specializations to respond to specific edaphic constraints of gypsum soils do not limit their ability to deal with other non-specific environmental constraints
Community structure informs species geographic distributions
This is the author accepted manuscript. The final version is available from Public Library of Science via the DOI in this recordUnderstanding what determines species’ geographic distributions is crucial for assessing
global change threats to biodiversity. Measuring limits on distributions is usually, and
necessarily, done with data at large geographic extents and coarse spatial resolution.
However, survival of individuals is determined by processes that happen at small spatial
assembly processes occurring at small scales, and are often available for relatively extensive
areas, so could be useful for explaining species distributions. We demonstrate that Bayesian
Network Inference (BNI) can overcome several challenges to including community structure
into studies of species distributions, despite having been little used to date. We hypothesized
that the relative abundance of coexisting species can improve predictions of species
distributions. In 1570 assemblages of 68 Mediterranean woody plant species we used BNI to
incorporate community structure into Species Distribution Models (SDMs), alongside
environmental information. Information on species associations improved SDM predictions
of community structure and species distributions moderately, though for some habitat
specialists the deviance explained increased by up to 15%. We demonstrate that most species
associations (95%) were positive and occurred between species with ecologically similar traits. This suggests that SDM improvement could be because species co-occurrences are a
proxy for local ecological processes. Our study shows that Bayesian Networks, when
interpreted carefully, can be used to include local conditions into measurements of species’
large-scale distributions, and this information can improve the predictions of species
distributionsThis work was funded by FCT Project “QuerCom” (EXPL/AAG-GLO/2488/2013) and the
ERA-Net BiodivERsA project “EC21C” (BIODIVERSA/0003/2011). A.M.N. was supported
by a Bolsa de Investigacao de Pos-doutoramento (BI_Pos-Doc_UEvora_Catedra Rui
Nabeiro_EXPL_AAG-GLO_2488_2013) and postdoctoral fellowships from the Ministry of
Economy and Competitivity (FPDI-2013-16266 and IJCI‐2015‐23498). MGM acknowledges
support by a Marie Curie Intra-European Fellowship within the 7th European Community
Framework Programme (FORECOMM). J. Vicente is supported by POPH/FSE funds and by
National Funds through FCT - Foundation for Science and Technology under the Portuguese
Science Foundation (FCT) through Post-doctoral grant SFRH/BPD/84044/2012. AE has a
postdoctoral contract funded by the project CN-17-022 (Principado de Asturias, Spain). We
are grateful to OneGeology for providing the geological data
CGIAR modeling approaches for resource-constrained scenarios: I. Accelerating crop breeding for a changing climate.
Crop improvement efforts aiming at increasing crop production (quantity, quality) and adapting to climate change have been subject of active research over the past years. But, the question remains 'to what extent can breeding gains be achieved under a changing climate, at a pace sufficient to usefully contribute to climate adaptation, mitigation and food security?'. Here, we address this question by critically reviewing how model-based approaches can be used to assist breeding activities, with particular focus on all CGIAR (formerly the Consultative Group on International Agricultural Research but now known simply as CGIAR) breeding programs. Crop modeling can underpin breeding efforts in many different ways, including assessing genotypic adaptability and stability, characterizing and identifying target breeding environments, identifying tradeoffs among traits for such environments, and making predictions of the likely breeding value of the genotypes. Crop modeling science within the CGIAR has contributed to all of these. However, much progress remains to be done if modeling is to effectively contribute to more targeted and impactful breeding programs under changing climates. In a period in which CGIAR breeding programs are undergoing a major modernization process, crop modelers will need to be part of crop improvement teams, with a common understanding of breeding pipelines and model capabilities and limitations, and common data standards and protocols, to ensure they follow and deliver according to clearly defined breeding products. This will, in turn, enable more rapid and better-targeted crop modeling activities, thus directly contributing to accelerated and more impactful breeding efforts.Online Version of Record before inclusion in an issue
Array-based DNA methylation profiling of primary lymphomas of the central nervous system
<p>Abstract</p> <p>Background</p> <p>Although primary lymphomas of the central nervous system (PCNSL) and extracerebral diffuse large B-cell lymphoma (DLBCL) cannot be distinguished histologically, it is still a matter of debate whether PCNSL differ from systemic DLBCL with respect to their molecular features and pathogenesis. Analysis of the DNA methylation pattern might provide further data distinguishing these entities at a molecular level.</p> <p>Methods</p> <p>Using an array-based technology we have assessed the DNA methylation status of 1,505 individual CpG loci in five PCNSL and compared the results to DNA methylation profiles of 49 DLBCL and ten hematopoietic controls.</p> <p>Results</p> <p>We identified 194 genes differentially methylated between PCNSL and normal controls. Interestingly, Polycomb target genes and genes with promoters showing a high CpG content were significantly enriched in the group of genes hypermethylated in PCNSL. However, PCNSL and systemic DLBCL did not differ in their methylation pattern.</p> <p>Conclusions</p> <p>Based on the data presented here, PCNSL and DLBCL do not differ in their DNA methylation pattern. Thus, DNA methylation analysis does not support a separation of PCNSL and DLBCL into individual entities. However, PCNSL and DLBCL differ in their DNA methylation pattern from non- malignant controls.</p
Height and timing of growth spurt during puberty in young people living with vertically acquired HIV in Europe and Thailand.
OBJECTIVE: The aim of this study was to describe growth during puberty in young people with vertically acquired HIV. DESIGN: Pooled data from 12 paediatric HIV cohorts in Europe and Thailand. METHODS: One thousand and ninety-four children initiating a nonnucleoside reverse transcriptase inhibitor or boosted protease inhibitor based regimen aged 1-10 years were included. Super Imposition by Translation And Rotation (SITAR) models described growth from age 8 years using three parameters (average height, timing and shape of the growth spurt), dependent on age and height-for-age z-score (HAZ) (WHO references) at antiretroviral therapy (ART) initiation. Multivariate regression explored characteristics associated with these three parameters. RESULTS: At ART initiation, median age and HAZ was 6.4 [interquartile range (IQR): 2.8, 9.0] years and -1.2 (IQR: -2.3 to -0.2), respectively. Median follow-up was 9.1 (IQR: 6.9, 11.4) years. In girls, older age and lower HAZ at ART initiation were independently associated with a growth spurt which occurred 0.41 (95% confidence interval 0.20-0.62) years later in children starting ART age 6 to 10 years compared with 1 to 2 years and 1.50 (1.21-1.78) years later in those starting with HAZ less than -3 compared with HAZ at least -1. Later growth spurts in girls resulted in continued height growth into later adolescence. In boys starting ART with HAZ less than -1, growth spurts were later in children starting ART in the oldest age group, but for HAZ at least -1, there was no association with age. Girls and boys who initiated ART with HAZ at least -1 maintained a similar height to the WHO reference mean. CONCLUSION: Stunting at ART initiation was associated with later growth spurts in girls. Children with HAZ at least -1 at ART initiation grew in height at the level expected in HIV negative children of a comparable age
On the fine structure of the sunspot penumbrae. III The vertical extension of penumbral filaments
In this paper we study the fine structure of the penumbra as inferred from
the uncombed model (flux tube embedded in a magnetic surrounding) when applied
to penumbral spectropolarimetric data from the neutral iron lines at 6300 \AA.
The inversion infers very similar radial dependences in the physical quantities
(LOS velocity, magnetic field strength etc) as those obtained from the
inversion of the Fe I 1.56 m lines. In addition, the large Stokes area
asymmetry exhibited by the visible lines helps to constrain the size of the
penumbral flux tubes. As we demonstrate here, the uncombed model is able to
reproduce the area asymmetry with striking accuracy, returning flux tubes as
thick as 100-300 kilometers in the vertical direction, in good agreement with
previous investigations.Comment: submitted to Astronomy and Astrophysic
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