118 research outputs found
First-Night Effect on Sleep in Different Female Reproductive States
Objectives: In sleep laboratory studies, the new environment is generally considered to disturb sleep during the first night. However, older women have rarely been studied. Although menopause and hormone therapy affect sleep, their impact on the first-night effect is virtually unknown. Participants: Four groups of women with no sleep laboratory experience: young on hormonal contraceptives (n = 11, 23.1 [0.5] years), perimenopausal (n = 15, 48.0 (0.4] years), postmenopausal without hormone therapy (HT; off-HT, n = 22, 63.4 [0.8] years) and postmenopausal with HT (n = 16, 63.1 [0.9] years). Procedure: A cross-sectional study. Methods: Polysomnography was performed over two consecutive nights and the first-night effect and group differences were evaluated. Questionnaire-based insomnia and sleepiness scores were correlated to sleep variables and their between-night changes. Results: Although sleep in young women was deeper and less fragmented than in the other groups, first-night effect was similar in all study groups. Total sleep time, sleep efficiency, and S1 and S2 sleep increased, and wake after sleep onset, awakenings per hour of sleep, S2 and REM latencies, and percentage of SWS decreased from the first to the second night. Perimenopausal women had more insomnia complaints than other women. Insomnia complaints were associated with more disturbed sleep but not with the first-night effect. Conclusions: A first night in a sleep laboratory elicits a marked interference of sleep architecture in women of all ages, with a carryover effect of lighter sleep on the second study night. Menopausal state, HT use, or insomnia complaints do not modify this effect.Peer reviewe
Human prefrontal cortex gene regulatory dynamics from gestation to adulthood at single-cell resolution.
Human brain development is underpinned by cellular and molecular reconfigurations continuing into the third decade of life. To reveal cell dynamics orchestrating neural maturation, we profiled human prefrontal cortex gene expression and chromatin accessibility at single-cell resolution from gestation to adulthood. Integrative analyses define the dynamic trajectories of each cell type, revealing major gene expression reconfiguration at the prenatal-to-postnatal transition in all cell types followed by continuous reconfiguration into adulthood and identifying regulatory networks guiding cellular developmental programs, states, and functions. We uncover links between expression dynamics and developmental milestones, characterize the diverse timing of when cells acquire adult-like states, and identify molecular convergence from distinct developmental origins. We further reveal cellular dynamics and their regulators implicated in neurological disorders. Finally, using this reference, we benchmark cell identities and maturation states in organoid models. Together, this captures the dynamic regulatory landscape of human cortical development.This work was supported by the following grants: R.L.—National Health and
Medical Research Council (NHMRC) Project Grant 1130168, NHMRC Investigator Grant 1178460, Silvia and Charles Viertel Senior Medical Research
Fellowship, Howard Hughes Medical Institute International Research Scholarship, and Australian Research Council (ARC) LE170100225; S.F.—NHMRC
Ideas Grant 1184421; I.V.—ARC Future Fellowship FT170100359, UNSW Scientia Fellowship, and NHMRC Project Grant RG170137; S.B.—NHMRC-ARC
Dementia Research Development Fellowship 1111206; C.P.—Raine Foundation Priming Grant RPG66-21; J.M.P.—Silvia and Charles Viertel Senior Medical Research Fellowship, ARC Future Fellowship FT180100674. This work
was supported by a Cancer Research Trust grant ‘‘Enabling advanced single
cell cancer genomics in WA’’ and Cancer Council WA enabling grant. Genomic
data were generated at the ACRF Centre for Advanced Cancer Genomics and
Genomics WA. Human brain tissue was received from the UMB Brain and Tissue Bank at the University of Maryland, part of the NIH NeuroBioBank. The
glioblastoma sample was procured and provided by the AGOG biobank,
funded by CINSW grant SRP-08-10. L.M. was a fellow of The Lorenzo and Pamela Galli Medical Research Trust. We thank Ankur Sharma and Greg Neely for
valuable feedback. The graphical abstract and elements of Figure 1A were
created with BioRender.S
Forest biomass density across large climate gradients in northern South America is related to water availability but not with temperature
Understanding and predicting the likely response of ecosystems to climate change are crucial challenges for ecology and for conservation biology. Nowhere is this challenge greater
than in the tropics as these forests store more than half the total atmospheric carbon stock
in their biomass. Biomass is determined by the balance between biomass inputs (i.e.,
growth) and outputs (mortality). We can expect therefore that conditions that favor high
growth rates, such as abundant water supply, warmth, and nutrient-rich soils will tend to correlate with high biomass stocks. Our main objective is to describe the patterns of above
ground biomass (AGB) stocks across major tropical forests across climatic gradients in
Northwestern South America. We gathered data from 200 plots across the region, at elevations ranging between 0 to 3400 m. We estimated AGB based on allometric equations and
values for stem density, basal area, and wood density weighted by basal area at the plotlevel. We used two groups of climatic variables, namely mean annual temperature and
actual evapotranspiration as surrogates of environmental energy, and annual precipitation,
precipitation seasonality, and water availability as surrogates of water availability. We found
that AGB is more closely related to water availability variables than to energy variables. In
northwest South America, water availability influences carbon stocks principally by determining stand structure, i.e. basal area. When water deficits increase in tropical forests we
can expect negative impact on biomass and hence carbon storage
Helicobacter pylori Diagnostic Tests Used in Europe : Results of over 34,000 Patients from the European Registry on Helicobacter pylori Management
Funding Information: This study was funded by Richen; however, clinical data were not accessible and the company was not involved in any stage of the Hp-EuReg study (design, data collection, statistical analysis, or manuscript writing). We want to thank Richen for their support. This project was promoted and funded by the European Helicobacter and Microbiota Study Group (EHMSG), the Spanish Association of Gastroenterology (AEG) and the Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd). The Hp-EuReg was co-funded by the European Union programme HORIZON (grant agreement number 101095359) and supported by the UK Research and Innovation (grant agreement number 10058099). The Hp-EuReg was co-funded by the European Union programme EU4Health (grant agreement number 101101252). Acknowledgments We want to especially thank Sylva-Astrik Torossian for her assistance in language editing. Natalia García Morales is the first author who is acting as the submission’s guarantor. All authors approved the final version of the manuscript.Peer reviewedPublisher PD
Evenness mediates the global relationship between forest productivity and richness
1. Biodiversity is an important component of natural ecosystems, with higher species richness often correlating with an increase in ecosystem productivity. Yet, this relationship varies substantially across environments, typically becoming less pronounced at high levels of species richness. However, species richness alone cannot reflect all important properties of a community, including community evenness, which may mediate the relationship between biodiversity and productivity. If the evenness of a community correlates negatively with richness across forests globally, then a greater number of species may not always increase overall diversity and productivity of the system. Theoretical work and local empirical studies have shown that the effect of evenness on ecosystem functioning may be especially strong at high richness levels, yet the consistency of this remains untested at a global scale. 2. Here, we used a dataset of forests from across the globe, which includes composition, biomass accumulation and net primary productivity, to explore whether productivity correlates with community evenness and richness in a way that evenness appears to buffer the effect of richness. Specifically, we evaluated whether low levels of evenness in speciose communities correlate with the attenuation of the richness–productivity relationship. 3. We found that tree species richness and evenness are negatively correlated across forests globally, with highly speciose forests typically comprising a few dominant and many rare species. Furthermore, we found that the correlation between diversity and productivity changes with evenness: at low richness, uneven communities are more productive, while at high richness, even communities are more productive. 4. Synthesis. Collectively, these results demonstrate that evenness is an integral component of the relationship between biodiversity and productivity, and that the attenuating effect of richness on forest productivity might be partly explained by low evenness in speciose communities. Productivity generally increases with species richness, until reduced evenness limits the overall increases in community diversity. Our research suggests that evenness is a fundamental component of biodiversity–ecosystem function relationships, and is of critical importance for guiding conservation and sustainable ecosystem management decisions
Native diversity buffers against severity of non-native tree invasions
Determining the drivers of non-native plant invasions is critical for managing native ecosystems and limiting the spread of invasive species. Tree invasions in particular have been relatively overlooked, even though they have the potential to transform ecosystems and economies. Here, leveraging global tree databases, we explore how the phylogenetic and functional diversity of native tree communities, human pressure and the environment influence the establishment of non-native tree species and the subsequent invasion severity. We find that anthropogenic factors are key to predicting whether a location is invaded, but that invasion severity is underpinned by native diversity, with higher diversity predicting lower invasion severity. Temperature and precipitation emerge as strong predictors of invasion strategy, with non-native species invading successfully when they are similar to the native community in cold or dry extremes. Yet, despite the influence of these ecological forces in determining invasion strategy, we find evidence that these patterns can be obscured by human activity, with lower ecological signal in areas with higher proximity to shipping ports. Our global perspective of non-native tree invasion highlights that human drivers influence non-native tree presence, and that native phylogenetic and functional diversity have a critical role in the establishment and spread of subsequent invasions
The global biogeography of tree leaf form and habit
Understanding what controls global leaf type variation in trees is crucial for comprehending their role in terrestrial ecosystems, including carbon, water and nutrient dynamics. Yet our understanding of the factors influencing forest leaf types remains incomplete, leaving us uncertain about the global proportions of needle-leaved, broadleaved, evergreen and deciduous trees. To address these gaps, we conducted a global, ground-sourced assessment of forest leaf-type variation by integrating forest inventory data with comprehensive leaf form (broadleaf vs needle-leaf) and habit (evergreen vs deciduous) records. We found that global variation in leaf habit is primarily driven by isothermality and soil characteristics, while leaf form is predominantly driven by temperature. Given these relationships, we estimate that 38% of global tree individuals are needle-leaved evergreen, 29% are broadleaved evergreen, 27% are broadleaved deciduous and 5% are needle-leaved deciduous. The aboveground biomass distribution among these tree types is approximately 21% (126.4 Gt), 54% (335.7 Gt), 22% (136.2 Gt) and 3% (18.7 Gt), respectively. We further project that, depending on future emissions pathways, 17-34% of forested areas will experience climate conditions by the end of the century that currently support a different forest type, highlighting the intensification of climatic stress on existing forests. By quantifying the distribution of tree leaf types and their corresponding biomass, and identifying regions where climate change will exert greatest pressure on current leaf types, our results can help improve predictions of future terrestrial ecosystem functioning and carbon cycling
The global biogeography of tree leaf form and habit.
Understanding what controls global leaf type variation in trees is crucial for comprehending their role in terrestrial ecosystems, including carbon, water and nutrient dynamics. Yet our understanding of the factors influencing forest leaf types remains incomplete, leaving us uncertain about the global proportions of needle-leaved, broadleaved, evergreen and deciduous trees. To address these gaps, we conducted a global, ground-sourced assessment of forest leaf-type variation by integrating forest inventory data with comprehensive leaf form (broadleaf vs needle-leaf) and habit (evergreen vs deciduous) records. We found that global variation in leaf habit is primarily driven by isothermality and soil characteristics, while leaf form is predominantly driven by temperature. Given these relationships, we estimate that 38% of global tree individuals are needle-leaved evergreen, 29% are broadleaved evergreen, 27% are broadleaved deciduous and 5% are needle-leaved deciduous. The aboveground biomass distribution among these tree types is approximately 21% (126.4 Gt), 54% (335.7 Gt), 22% (136.2 Gt) and 3% (18.7 Gt), respectively. We further project that, depending on future emissions pathways, 17-34% of forested areas will experience climate conditions by the end of the century that currently support a different forest type, highlighting the intensification of climatic stress on existing forests. By quantifying the distribution of tree leaf types and their corresponding biomass, and identifying regions where climate change will exert greatest pressure on current leaf types, our results can help improve predictions of future terrestrial ecosystem functioning and carbon cycling
Native diversity buffers against severity of non-native tree invasions.
Determining the drivers of non-native plant invasions is critical for managing native ecosystems and limiting the spread of invasive species1,2. Tree invasions in particular have been relatively overlooked, even though they have the potential to transform ecosystems and economies3,4. Here, leveraging global tree databases5-7, we explore how the phylogenetic and functional diversity of native tree communities, human pressure and the environment influence the establishment of non-native tree species and the subsequent invasion severity. We find that anthropogenic factors are key to predicting whether a location is invaded, but that invasion severity is underpinned by native diversity, with higher diversity predicting lower invasion severity. Temperature and precipitation emerge as strong predictors of invasion strategy, with non-native species invading successfully when they are similar to the native community in cold or dry extremes. Yet, despite the influence of these ecological forces in determining invasion strategy, we find evidence that these patterns can be obscured by human activity, with lower ecological signal in areas with higher proximity to shipping ports. Our global perspective of non-native tree invasion highlights that human drivers influence non-native tree presence, and that native phylogenetic and functional diversity have a critical role in the establishment and spread of subsequent invasions
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