Partitioning controls on Amazon forest photosynthesis between environmental and biotic factors at hourly to interannual timescales

Gross ecosystem productivity (GEP) in tropical forests varies both with the environment and with biotic changes in photosynthetic infrastructure, but our understanding of the relative effects of these factors across timescales is limited. Here, we used a statistical model to partition the variability of seven years of eddy covariance-derived GEP in a central Amazon evergreen forest into two main causes: variation in environmental drivers (solar radiation, diffuse light fraction, and vapor pressure deficit) that interact with model parameters that govern photosynthesis and biotic variation in canopy photosynthetic light-use efficiency associated with changes in the parameters themselves. Our fitted model was able to explain most of the variability in GEP at hourly (R2 = 0.77) to interannual (R2 = 0.80) timescales. At hourly timescales, we found that 75% of observed GEP variability could be attributed to environmental variability. When aggregating GEP to the longer timescales (daily, monthly, and yearly), however, environmental variation explained progressively less GEP variability: At monthly timescales, it explained only 3%, much less than biotic variation in canopy photosynthetic light-use efficiency, which accounted for 63%. These results challenge modeling approaches that assume GEP is primarily controlled by the environment at both short and long timescales. Our approach distinguishing biotic from environmental variability can help to resolve debates about environmental limitations to tropical forest photosynthesis. For example, we found that biotically regulated canopy photosynthetic light-use efficiency (associated with leaf phenology) increased with sunlight during dry seasons (consistent with light but not water limitation of canopy development) but that realized GEP was nonetheless lower relative to its potential efficiency during dry than wet seasons (consistent with water limitation of photosynthesis in given assemblages of leaves). This work highlights the importance of accounting for differential regulation of GEP at different timescales and of identifying the underlying feedbacks and adaptive mechanisms

Bisectors of the HARPS Cross-Correlation-Function. The dependence on stellar atmospheric parameters

Bisectors of the HARPS cross-correlation function (CCF) can discern between planetary radial-velocity (RV) signals and spurious RV signals from stellar magnetic activity variations. However, little is known about the effects of the stellar atmosphere on CCF bisectors or how these effects vary with spectral type and luminosity class. Here we investigate the variations in the shapes of HARPS CCF bisectors across the HR diagram in order to relate these to the basic stellar parameters, surface gravity and temperature. We use archive spectra of 67 well studied stars observed with HARPS and extract mean CCF bisectors. We derive previously defined bisector measures (BIS, v_bot, c_b) and we define and derive a new measure called the CCF Bisector Span (CBS) from the minimum radius of curvature on direct fits to the CCF bisector. We show that the bisector measures correlate differently, and non-linearly with log g and T_eff. The resulting correlations allow for the estimation of log g and T_eff from the bisector measures. We compare our results with 3D stellar atmosphere models and show that we can reproduce the shape of the CCF bisector for the Sun.Comment: 13 pages, 20 figures. Accepted by A&

Ecosystem heterogeneity and diversity mitigate Amazon forest resilience to frequent extreme droughts

© 2018 The Authors. New Phytologist © 2018 New Phytologist Trust The impact of increases in drought frequency on the Amazon forest's composition, structure and functioning remain uncertain. We used a process- and individual-based ecosystem model (ED2) to quantify the forest's vulnerability to increased drought recurrence. We generated meteorologically realistic, drier-than-observed rainfall scenarios for two Amazon forest sites, Paracou (wetter) and Tapajós (drier), to evaluate the impacts of more frequent droughts on forest biomass, structure and composition. The wet site was insensitive to the tested scenarios, whereas at the dry site biomass declined when average rainfall reduction exceeded 15%, due to high mortality of large-sized evergreen trees. Biomass losses persisted when year-long drought recurrence was shorter than 2–7 yr, depending upon soil texture and leaf phenology. From the site-level scenario results, we developed regionally applicable metrics to quantify the Amazon forest's climatological proximity to rainfall regimes likely to cause biomass loss > 20% in 50 yr according to ED2 predictions. Nearly 25% (1.8 million km2) of the Amazon forests could experience frequent droughts and biomass loss if mean annual rainfall or interannual variability changed by 2σ. At least 10% of the high-emission climate projections (CMIP5/RCP8.5 models) predict critically dry regimes over 25% of the Amazon forest area by 2100

Telepsychiatry During the COVID-19 Pandemic: Development of a Protocol for Telemental Health Care

Background The rapid spread of the Coronavirus disease 2019 (COVID-19) has forced most countries to take drastic public health measures, including the closure of most mental health outpatient services and some inpatient units. This has suddenly created the need to adapt and expand telepsychiatry care across the world. However, not all health care services might be ready to cope with this public health demand. The present study was set to create a practical and clinically useful protocol for telemental health care to be applied in the context of the current COVID-19 pandemic. Methods A panel of psychiatrists from 15 different countries [covering all World Health Organization (WHO) regions] was convened. The panel used a combination of reactive Delphi technique and consensus development conference strategies to develop a protocol for the provision of telemental health care during the COVID-19 pandemic. Results The proposed protocol describes a semi-structured initial assessment and a series of potential interventions matching mild, moderate, or high-intensity needs of target populations. Conclusions Telemedicine has become a pivotal tool in the task of ensuring the continuous provision of mental health care for the population, and the outlined protocol can assist with this task. The strength of this protocol lies in its practicality, clinical usefulness, and wide transferability, resulting from the diversity of the consensus group that developed it. Developed by psychiatrists from around the globe, the proposed protocol may prove helpful for many clinical and cultural contexts, assisting mental health care providers worldwide

COVID-19 mental health care toolkit: an international collaborative effort by Early Career Psychiatrists section

The collaborative effort of an international research team from the Early Career Psychiatrists section of the World Psychiatry Association has brought about an easy-to-use, quick and stepwise mental health care toolkit for the identification and appropriate referral of those in need of mental health care during the pandemic. This simple guide can be applied in the general outpatient setting and is catered for all healthcare professionals, regardless of their expertise within the mental health field with minimal training. It is our hope that by incorporating this toolkit into our daily clinical care during the pandemic for high-risk patients and patients with non-specific complaints, we will be able to bridge the mental health gap present in our society

Epithelial-Mesenchymal Transition in Cells Expanded In Vitro from Lineage-Traced Adult Human Pancreatic Beta Cells

BACKGROUND: In-vitro expansion of functional beta cells from adult human islets is an attractive approach for generating an abundant source of cells for beta-cell replacement therapy of diabetes. Using genetic cell-lineage tracing we have recently shown that beta cells cultured from adult human islets undergo rapid dedifferentiation and proliferate for up to 16 population doublings. These cells have raised interest as potential candidates for redifferentiation into functional insulin-producing cells. Previous work has associated dedifferentiation of cultured epithelial cells with epithelial-mesenchymal transition (EMT), and suggested that EMT generates cells with stem cell properties. Here we investigated the occurrence of EMT in these cultures and assessed their stem cell potential. METHODOLOGY/PRINCIPAL FINDINGS: Using cell-lineage tracing we provide direct evidence for occurrence of EMT in cells originating from beta cells in cultures of adult human islet cells. These cells express multiple mesenchymal markers, as well as markers associated with mesenchymal stem cells (MSC). However, we do not find evidence for the ability of such cells, nor of cells in these cultures derived from a non-beta-cell origin, to significantly differentiate into mesodermal cell types. CONCLUSIONS/SIGNIFICANCE: These findings constitute the first demonstration based on genetic lineage-tracing of EMT in cultured adult primary human cells, and show that EMT does not induce multipotency in cells derived from human beta cells

Anticorpo monoclonal no manejo da cefaleia em salvas: Monoclonal antibody in the management of cluster headache

Introdução: A cefaleia em salvas (CS) é caracterizada por uma dor de cabeça intensa em apenas um lado da cabeça, que surge em crises. Não há cura para a CS e o seu tratamento consiste em minimizar a dor e diminuir a frequência das crises. Nesse cenário, que surge a investigação de maneiras eficazes para promover esse tratamento, entre eles o anticorpo monoclonal. Objetivo: Mostrar o que estudos recentes sobre o emprego de anticorpo monoclonal para esse fim têm trazido sobre sua segurança e eficácia. Metodologia: Trata-se de uma revisão sistemática da literatura realizada nos bancos de dados PubMed e BVS, com: “(Cluster Headache OR Headache Disorders) AND Antibodies, Monoclonal”. Excluiu-se os artigos que não se enquadravam nos objetivos. Resultados e Discussão: Grande parte dos estudos mostrou uma melhora significativa na frequência das crises, enquanto o uso para diminuir foi inconclusivo em quase todos estudos, principalmente quando usado a longo prazo, mas apesar disso, foi considerada uma opção segura para uso. Conclusão: É um tema ainda novo e com poucos estudos, principalmente de longos prazos, que diverge sobre a eficácia na redução da dor durante as crises, mas tende a convergir sobre a eficiência para redução dos intervalos das crises