The Amazon forest is the largest source of isoprene emissions, and the seasonal pattern of leaf-out phenology in this forest has been indicated as an important driver of seasonal variation in emissions. Still, it is unclear how emissions vary between different leaf phenological types in this forest. To evaluate the influence of leaf phenological type over isoprene emissions, we measured leaf-level isoprene emission capacity and leaf functional traits for 175 trees from 124 species of angiosperms distributed among brevideciduous and evergreen trees in a central Amazon forest.
View Article and Find Full Text PDFAmazonia contains the most extensive tropical forests on Earth, but Amazon carbon sinks of atmospheric CO are declining, as deforestation and climate-change-associated droughts threaten to push these forests past a tipping point towards collapse. Forests exhibit complex drought responses, indicating both resilience (photosynthetic greening) and vulnerability (browning and tree mortality), that are difficult to explain by climate variation alone. Here we combine remotely sensed photosynthetic indices with ground-measured tree demography to identify mechanisms underlying drought resilience/vulnerability in different intact forest ecotopes (defined by water-table depth, soil fertility and texture, and vegetation characteristics).
View Article and Find Full Text PDFFor more than three decades, major efforts in sampling and analyzing tree diversity in South America have focused almost exclusively on trees with stems of at least 10 and 2.5 cm diameter, showing highest species diversity in the wetter western and northern Amazon forests. By contrast, little attention has been paid to patterns and drivers of diversity in the largest canopy and emergent trees, which is surprising given these have dominant ecological functions.
View Article and Find Full Text PDFThe severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Gamma variant of concern has spread rapidly across Brazil since late 2020, causing substantial infection and death waves. Here we used individual-level patient records after hospitalization with suspected or confirmed coronavirus disease 2019 (COVID-19) between 20 January 2020 and 26 July 2021 to document temporary, sweeping shocks in hospital fatality rates that followed the spread of Gamma across 14 state capitals, during which typically more than half of hospitalized patients aged 70 years and older died. We show that such extensive shocks in COVID-19 in-hospital fatality rates also existed before the detection of Gamma.
View Article and Find Full Text PDFUnlabelled: The SARS-CoV-2 Gamma variant spread rapidly across Brazil, causing substantial infection and death waves. We use individual-level patient records following hospitalisation with suspected or confirmed COVID-19 to document the extensive shocks in hospital fatality rates that followed Gamma's spread across 14 state capitals, and in which more than half of hospitalised patients died over sustained time periods. We show that extensive fluctuations in COVID-19 in-hospital fatality rates also existed prior to Gamma's detection, and were largely transient after Gamma's detection, subsiding with hospital demand.
View Article and Find Full Text PDFHigh-quality atmospheric CO measurements are sparse in Amazonia, but can provide critical insights into the spatial and temporal variability of sources and sinks of CO . In this study, we present the first 6 years (2014-2019) of continuous, high-precision measurements of atmospheric CO at the Amazon Tall Tower Observatory (ATTO, 2.1°S, 58.
View Article and Find Full Text PDFCases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in Manaus, Brazil, resurged in late 2020 despite previously high levels of infection. Genome sequencing of viruses sampled in Manaus between November 2020 and January 2021 revealed the emergence and circulation of a novel SARS-CoV-2 variant of concern. Lineage P.
View Article and Find Full Text PDFCases of SARS-CoV-2 infection in Manaus, Brazil, resurged in late 2020, despite high levels of previous infection there. Through genome sequencing of viruses sampled in Manaus between November 2020 and January 2021, we identified the emergence and circulation of a novel SARS-CoV-2 variant of concern, lineage P.1, that acquired 17 mutations, including a trio in the spike protein (K417T, E484K and N501Y) associated with increased binding to the human ACE2 receptor.
View Article and Find Full Text PDFMajor and trace element deposition across western Washington, USA was assessed in 2016 and 2017 by analyzing tissue metal concentrations in the epiphytic mosses Isothecium stoloniferum (Bridel) and Kindbergia praelonga (Hedw.) Ochyra. We used an intensive, vertically stratified sampling approach in Acer macrophyllum canopies in the Hoh Rainforest on the Olympic Peninsula, WA and in Seattle, WA to collect 214 samples of I.
View Article and Find Full Text PDFGlob Chang Biol
September 2018
Sustained drought and concomitant high temperature may reduce photosynthesis and cause tree mortality. Possible causes of reduced photosynthesis include stomatal closure and biochemical inhibition, but their relative roles are unknown in Amazon trees during strong drought events. We assessed the effects of the recent (2015) strong El Niño drought on leaf-level photosynthesis of Central Amazon trees via these two mechanisms.
View Article and Find Full Text PDFSatellite observations of Amazon forests show seasonal and interannual variations, but the underlying biological processes remain debated. Here we combined radiative transfer models (RTMs) with field observations of Amazon forest leaf and canopy characteristics to test three hypotheses for satellite-observed canopy reflectance seasonality: seasonal changes in leaf area index, in canopy-surface leafless crown fraction and/or in leaf demography. Canopy RTMs (PROSAIL and FLiES), driven by these three factors combined, simulated satellite-observed seasonal patterns well, explaining c.
View Article and Find Full Text PDFWe compared religiously integrated cognitive behavioral therapy (RCBT) versus conventional CBT (CCBT) on increasing daily spiritual experiences (DSE) in major depressive disorder and chronic medical illness. A total of 132 participants aged 18-85 were randomized to either RCBT (n = 65) or CCBT (n = 67). Participants received ten 50-min sessions (primarily by telephone) over 12 weeks.
View Article and Find Full Text PDFObjectives: To examine the relationship between religious involvement (RI) and adaptation of women caring for family members with severe physical or neurological disability.
Design: Two-site cross-sectional study.
Setting: Community.
In evergreen tropical forests, the extent, magnitude, and controls on photosynthetic seasonality are poorly resolved and inadequately represented in Earth system models. Combining camera observations with ecosystem carbon dioxide fluxes at forests across rainfall gradients in Amazônia, we show that aggregate canopy phenology, not seasonality of climate drivers, is the primary cause of photosynthetic seasonality in these forests. Specifically, synchronization of new leaf growth with dry season litterfall shifts canopy composition toward younger, more light-use efficient leaves, explaining large seasonal increases (~27%) in ecosystem photosynthesis.
View Article and Find Full Text PDFTelomere length (TL) is an indicator of cellular aging associated with longevity and psychosocial stress. We examine here the relationship between religious involvement and TL in 251 stressed female family caregivers recruited into a 2-site study. Religious involvement, perceived stress, caregiver burden, depressive symptoms, and social support were measured and correlated with TL in whole blood leukocytes.
View Article and Find Full Text PDFBackground: We compared the effectiveness of religiously integrated cognitive behavioral therapy (RCBT) versus standard CBT (SCBT) on increasing optimism in persons with major depressive disorder (MDD) and chronic medical illness.
Methods: Participants aged 18-85 were randomized to either RCBT (n = 65) or SCBT (n = 67) to receive ten 50-min sessions remotely (94% by telephone) over 12 weeks. Optimism was assessed at baseline, 12 and 24 weeks by the Life Orientation Test-Revised.
We studied the tree-regeneration patterns in three distinct agricultural settlements in the Eastern Amazon to test the influence of land-use mosaics. The following questions are addressed: are the floristic structure and composition of regenerating trees affected by the various land-use types applied in the agricultural settlements? Do tree-regeneration patterns respond similarly to distinct land-use mosaics? Is there a relationship between tree regeneration and soil characteristics among the land-use types? The regeneration was inventoried at 45 sampling points in each settlement. At each sampling point, fourteen soil variables were analyzed.
View Article and Find Full Text PDFWe examine the efficacy of conventional cognitive behavioral therapy (CCBT) versus religiously integrated CBT (RCBT) in persons with major depression and chronic medical illness. Participants were randomized to either CCBT (n = 67) or RCBT (n = 65). The intervention in both groups consisted of ten 50-minute sessions delivered remotely during 12 weeks (94% by telephone).
View Article and Find Full Text PDFBackground: Treatments that integrate religious clients' beliefs into therapy may enhance the therapeutic alliance (TA) in religious clients.
Objective: Compare the effects of religiously integrated cognitive behavioral therapy (RCBT) and standard CBT (SCBT) on TA in adults with major depression and chronic medical illness.
Method: Multi-site randomized controlled trial in 132 participants, of whom 108 (SCBT = 53, RCBT = 55) completed the Revised Helping Alliance Questionnaire (HAQ-II) at 4, 8, and 12 weeks.