RESUMEN
Amazonia contains the most extensive tropical forests on Earth, but Amazon carbon sinks of atmospheric CO2 are declining, as deforestation and climate-change-associated droughts1-4 threaten to push these forests past a tipping point towards collapse5-8. Forests exhibit complex drought responses, indicating both resilience (photosynthetic greening) and vulnerability (browning and tree mortality), that are difficult to explain by climate variation alone9-17. Here we combine remotely sensed photosynthetic indices with ground-measured tree demography to identify mechanisms underlying drought resilience/vulnerability in different intact forest ecotopes18,19 (defined by water-table depth, soil fertility and texture, and vegetation characteristics). In higher-fertility southern Amazonia, drought response was structured by water-table depth, with resilient greening in shallow-water-table forests (where greater water availability heightened response to excess sunlight), contrasting with vulnerability (browning and excess tree mortality) over deeper water tables. Notably, the resilience of shallow-water-table forest weakened as drought lengthened. By contrast, lower-fertility northern Amazonia, with slower-growing but hardier trees (or, alternatively, tall forests, with deep-rooted water access), supported more-drought-resilient forests independent of water-table depth. This functional biogeography of drought response provides a framework for conservation decisions and improved predictions of heterogeneous forest responses to future climate changes, warning that Amazonia's most productive forests are also at greatest risk, and that longer/more frequent droughts are undermining multiple ecohydrological strategies and capacities for Amazon forest resilience.
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Resistencia a la Sequía , Sequías , Bosques , Agua Subterránea , Fotosíntesis , Suelo , Luz Solar , Árboles , Brasil , Secuestro de Carbono , Sequías/estadística & datos numéricos , Agua Subterránea/análisis , Suelo/química , Árboles/clasificación , Árboles/metabolismo , Árboles/fisiología , Clima Tropical , Resistencia a la Sequía/fisiología , Filogeografía , Conservación de los Recursos NaturalesRESUMEN
The 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. Using a Bayesian fatality rate model, we found that the geographic and temporal fluctuations in Brazil's COVID-19 in-hospital fatality rates were primarily associated with geographic inequities and shortages in healthcare capacity. We estimate that approximately half of the COVID-19 deaths in hospitals in the 14 cities could have been avoided without pre-pandemic geographic inequities and without pandemic healthcare pressure. Our results suggest that investments in healthcare resources, healthcare optimization and pandemic preparedness are critical to minimize population-wide mortality and morbidity caused by highly transmissible and deadly pathogens such as SARS-CoV-2, especially in low- and middle-income countries.
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COVID-19 , Anciano , Anciano de 80 o más Años , Teorema de Bayes , Brasil/epidemiología , COVID-19/epidemiología , Hospitales , Humanos , SARS-CoV-2RESUMEN
Predictions of the magnitude and timing of leaf phenology in Amazonian forests remain highly controversial. Here, we use terrestrial LiDAR surveys every two weeks spanning wet and dry seasons in Central Amazonia to show that plant phenology varies strongly across vertical strata in old-growth forests, but is sensitive to disturbances arising from forest fragmentation. In combination with continuous microclimate measurements, we find that when maximum daily temperatures reached 35 °C in the latter part of the dry season, the upper canopy of large trees in undisturbed forests lost plant material. In contrast, the understory greened up with increased light availability driven by the upper canopy loss, alongside increases in solar radiation, even during periods of drier soil and atmospheric conditions. However, persistently high temperatures in forest edges exacerbated the upper canopy losses of large trees throughout the dry season, whereas the understory in these light-rich environments was less dependent on the altered upper canopy structure. Our findings reveal a strong influence of edge effects on phenological controls in wet forests of Central Amazonia.
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Bosques , Hojas de la Planta/fisiología , Árboles/fisiología , Brasil , Luz , Microclima , Estaciones del Año , Suelo/química , Agua/químicaRESUMEN
High-quality atmospheric CO2 measurements are sparse in Amazonia, but can provide critical insights into the spatial and temporal variability of sources and sinks of CO2 . In this study, we present the first 6 years (2014-2019) of continuous, high-precision measurements of atmospheric CO2 at the Amazon Tall Tower Observatory (ATTO, 2.1°S, 58.9°W). After subtracting the simulated background concentrations from our observational record, we define a CO2 regional signal ( ΔCO2obs ) that has a marked seasonal cycle with an amplitude of about 4 ppm. At both seasonal and inter-annual scales, we find differences in phase between ΔCO2obs and the local eddy covariance net ecosystem exchange (EC-NEE), which is interpreted as an indicator of a decoupling between local and non-local drivers of ΔCO2obs . In addition, we present how the 2015-2016 El Niño-induced drought was captured by our atmospheric record as a positive 2σ anomaly in both the wet and dry season of 2016. Furthermore, we analyzed the observed seasonal cycle and inter-annual variability of ΔCO2obs together with net ecosystem exchange (NEE) using a suite of modeled flux products representing biospheric and aquatic CO2 exchange. We use both non-optimized and optimized (i.e., resulting from atmospheric inverse modeling) NEE fluxes as input in an atmospheric transport model (STILT). The observed shape and amplitude of the seasonal cycle was captured neither by the simulations using the optimized fluxes nor by those using the diagnostic Vegetation and Photosynthesis Respiration Model (VPRM). We show that including the contribution of CO2 from river evasion improves the simulated shape (not the magnitude) of the seasonal cycle when using a data-driven non-optimized NEE product (FLUXCOM). The simulated contribution from river evasion was found to be 25% of the seasonal cycle amplitude. Our study demonstrates the importance of the ATTO record to better understand the Amazon carbon cycle at various spatial and temporal scales.
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Dióxido de Carbono , Ecosistema , Ciclo del Carbono , Ríos , Estaciones del AñoRESUMEN
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. Using a Bayesian fatality rate model, we find that the geographic and temporal fluctuations in Brazil's COVID-19 in-hospital fatality rates are primarily associated with geographic inequities and shortages in healthcare capacity. We project that approximately half of Brazil's COVID-19 deaths in hospitals could have been avoided without pre-pandemic geographic inequities and without pandemic healthcare pressure. Our results suggest that investments in healthcare resources, healthcare optimization, and pandemic preparedness are critical to minimize population wide mortality and morbidity caused by highly transmissible and deadly pathogens such as SARS-CoV-2, especially in low- and middle-income countries. NOTE: The following manuscript has appeared as 'Report 46 - Factors driving extensive spatial and temporal fluctuations in COVID-19 fatality rates in Brazilian hospitals' at https://spiral.imperial.ac.uk:8443/handle/10044/1/91875 . ONE SENTENCE SUMMARY: COVID-19 in-hospital fatality rates fluctuate dramatically in Brazil, and these fluctuations are primarily associated with geographic inequities and shortages in healthcare capacity.
RESUMEN
Cases 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.1 acquired 17 mutations, including a trio in the spike protein (K417T, E484K, and N501Y) associated with increased binding to the human ACE2 (angiotensin-converting enzyme 2) receptor. Molecular clock analysis shows that P.1 emergence occurred around mid-November 2020 and was preceded by a period of faster molecular evolution. Using a two-category dynamical model that integrates genomic and mortality data, we estimate that P.1 may be 1.7- to 2.4-fold more transmissible and that previous (non-P.1) infection provides 54 to 79% of the protection against infection with P.1 that it provides against non-P.1 lineages. Enhanced global genomic surveillance of variants of concern, which may exhibit increased transmissibility and/or immune evasion, is critical to accelerate pandemic responsiveness.
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COVID-19/epidemiología , COVID-19/virología , Enfermedades Transmisibles Emergentes/epidemiología , Enfermedades Transmisibles Emergentes/virología , SARS-CoV-2/clasificación , SARS-CoV-2/genética , Glicoproteína de la Espiga del Coronavirus/genética , Enzima Convertidora de Angiotensina 2/metabolismo , Brasil/epidemiología , Monitoreo Epidemiológico , Genoma Viral , Genómica , Humanos , Modelos Teóricos , Epidemiología Molecular , Mutación , Unión Proteica , SARS-CoV-2/aislamiento & purificación , Glicoproteína de la Espiga del Coronavirus/metabolismo , Carga ViralRESUMEN
Cases 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. Molecular clock analysis shows that P.1 emergence occurred around early November 2020 and was preceded by a period of faster molecular evolution. Using a two-category dynamical model that integrates genomic and mortality data, we estimate that P.1 may be 1.4-2.2 times more transmissible and 25-61% more likely to evade protective immunity elicited by previous infection with non-P.1 lineages. Enhanced global genomic surveillance of variants of concern, which may exhibit increased transmissibility and/or immune evasion, is critical to accelerate pandemic responsiveness.
RESUMEN
Cases 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.1 acquired 17 mutations, including a trio in the spike protein (K417T, E484K, and N501Y) associated with increased binding to the human ACE2 (angiotensin-converting enzyme 2) receptor. Molecular clock analysis shows that P.1 emergence occurred around mid-November 2020 and was preceded by a period of faster molecular evolution. Using a two-category dynamical model that integrates genomic and mortality data, we estimate that P.1 may be 1.7- to 2.4-fold more transmissible and that previous (non-P.1) infection provides 54 to 79% of the protection against infection with P.1 that it provides against non-P.1 lineages. Enhanced global genomic surveillance of variants of concern, which may exhibit increased transmissibility and/or immune evasion, is critical to accelerate pandemic responsiveness.
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Angiotensinas , Genoma , BetacoronavirusRESUMEN
Major 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. stoloniferum. An extensive, ground-based sampling approach was used across an urban-to-wildland gradient to collect 59 K. praelonga samples. Intensive samples were collected four times (April, July, and October of 2016 and in January 2017) and extensive samples three times (April, July, and October 2016) to assess seasonal differences in metal concentrations across sampling locations. A total of 273 moss samples were analyzed for Cd, Cr, Cu, Fe, K, Mg, Mn, Ni, Pb, Sr, Ti, and Zn concentrations. Elevated concentrations of these elements were found in moss samples from both intensive and extensive sampling efforts across all seasons. Sampling location for both intensive and extensive sampling efforts was found to be a significant factor in determining moss metal concentrations. Metal deposition in and around Seattle appears to be derived from the regional transportation sector and other industrial sources. Ten I. stoloniferum samples from Seattle and the Hoh Rainforest were analyzed for Pb and Sr isotope ratios to help differentiate between natural and industrial-based emission sources. Hoh Rainforest Pb isotopes appear to be explained by a mixture of long-range Asian Pb influences and natural Pb sources, whereas Seattle Pb isotopes appear driven by industrial and road dust sources.
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Contaminantes Atmosféricos/metabolismo , Bryopsida/química , Monitoreo del Ambiente , Metales Pesados/metabolismo , Oligoelementos/metabolismo , Estaciones del Año , WashingtónRESUMEN
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. Through four seasons of 2015, we measured leaf gas exchange, chlorophyll a fluorescence parameters, chlorophyll concentration, and nutrient content in leaves of 57 upper canopy and understory trees of a lowland terra firme forest on well-drained infertile oxisol. Photosynthesis decreased 28% in the upper canopy and 17% in understory trees during the extreme dry season of 2015, relative to other 2015 seasons and was also lower than the climatically normal dry season of the following non-El Niño year. Photosynthesis reduction under extreme drought and high temperature in the 2015 dry season was related only to stomatal closure in both upper canopy and understory trees, and not to chlorophyll a fluorescence parameters, chlorophyll, or leaf nutrient concentration. The distinction is important because stomatal closure is a transient regulatory response that can reverse when water becomes available, whereas the other responses reflect more permanent changes or damage to the photosynthetic apparatus. Photosynthesis decrease due to stomatal closure during the 2015 extreme dry season was followed 2 months later by an increase in photosynthesis as rains returned, indicating a margin of resilience to one-off extreme climatic events in Amazonian forests.
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Sequías , El Niño Oscilación del Sur , Bosques , Fotosíntesis/fisiología , Árboles/fisiología , Brasil , Hojas de la Planta/fisiología , Estaciones del AñoRESUMEN
Satellite 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. 70% of the variability in a key reflectance-based vegetation index (MAIAC EVI, which removes artifacts that would otherwise arise from clouds/aerosols and sun-sensor geometry). Leaf area index, leafless crown fraction and leaf demography independently accounted for 1, 33 and 66% of FLiES-simulated EVI seasonality, respectively. These factors also strongly influenced modeled near-infrared (NIR) reflectance, explaining why both modeled and observed EVI, which is especially sensitive to NIR, captures canopy seasonal dynamics well. Our improved analysis of canopy-scale biophysics rules out satellite artifacts as significant causes of satellite-observed seasonal patterns at this site, implying that aggregated phenology explains the larger scale remotely observed patterns. This work significantly reconciles current controversies about satellite-detected Amazon phenology, and improves our use of satellite observations to study climate-phenology relationships in the tropics.
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Fenómenos Biológicos , Bosques , Hojas de la Planta/fisiología , Estaciones del Año , Modelos Biológicos , Fenómenos Ópticos , Hojas de la Planta/crecimiento & desarrolloRESUMEN
We 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. DSE was assessed using the Daily Spiritual Experiences Scale (DSES). Mixed-effects growth curve models compared the effects of treatment group on trajectory of change in DSE. Baseline DSE and changes in DSE were examined as predictors of change in depressive symptoms. DSE increased significantly in both groups. RCBT tended to be more effective than CCBT with regard to increasing DSE (group by time interaction B = -1.80, SE = 1.32, t = -1.36, p = 0.18), especially in those with low religiosity (B = -4.26, SE = 2.27, t = -1.88, p = 0.07). Higher baseline DSE predicted a decrease in depressive symptoms (B = -0.09, SE = 0.04, t = -2.25, p = 0.025), independent of treatment group, and an increase in DSE with treatment correlated with a decrease in depressive symptoms (r = 0.29, p = 0.004). RCBT tends to be more effective than CCBT in increasing DSE, especially in persons with low religiosity. Higher baseline DSE and increases in DSE over time predict a faster resolution of depressive symptoms. Efforts to increase DSE, assessed by a measure such as the DSES, may help with the treatment of depression in the medically ill.
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Terapia Cognitivo-Conductual/métodos , Trastorno Depresivo Mayor/terapia , Espiritualidad , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , North Carolina , South Carolina , Adulto JovenRESUMEN
OBJECTIVES: 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. PARTICIPANTS: A convenience sample of 251 caregivers was recruited. RI and caregiver adaptation (assessed by perceived stress, caregiver burden, and depressive symptoms) were measured using standard scales, along with caregiver characteristics, social support, and health behaviors. Bivariate and multivariate analyses were conducted to identify relationships and mediating and moderating factors. RESULTS: Religious involvement (RI) was associated with better caregiver adaptation independent of age, race, education, caregiver health, care recipient's health, social support, and health behaviors (B = -0.09, standard error = 0.04, t = -2.08, P = .04). This association was strongest in caregivers aged 58-75 and spouses and for perceived stress in blacks. CONCLUSION: Religious involvement (RI) in female caregivers is associated with better caregiver adaptation, especially for those who are older, spouses of the care recipients, and blacks. These results are relevant to the development of future interventions that provide support to family caregivers.
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Adaptación Psicológica , Cuidadores/psicología , Familia/psicología , Religión y Psicología , Factores Sexuales , Adulto , Negro o Afroamericano , Factores de Edad , Anciano , Estudios Transversales , Femenino , Humanos , Persona de Mediana Edad , Análisis Multivariante , Apoyo Social , Esposos/psicología , Estrés PsicológicoRESUMEN
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. Coordinated leaf development and demography thus reconcile seemingly disparate observations at different scales and indicate that accounting for leaf-level phenology is critical for accurately simulating ecosystem-scale responses to climate change.
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Cambio Climático , Bosques , Fotosíntesis , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/metabolismo , Clima Tropical , Demografía , Luz , Estaciones del AñoRESUMEN
BACKGROUND: 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. Trajectory of change in scores over time was compared between groups. RESULTS: HAQ-II score at 4 weeks predicted a decline in depressive symptoms over time independent of treatment group (B = -0.06, SE = 0.02, p = 0.002, n = 108). There was a marginally significant difference in HAQ-II scores at 4 weeks that favored RCBT (p = 0.076); however, the mixed effects model indicated a significant group by time interaction that favored the SCBT group (B = 1.84, SE = 0.90, degrees of freedom = 181, t = 2.04, p = 0.043, d = 0.30). CONCLUSIONS: While RCBT produces a marginally greater improvement in TA initially compared with SCBT, SCBT soon catches up.
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Terapia Cognitivo-Conductual/métodos , Trastorno Depresivo Mayor/terapia , Evaluación de Procesos y Resultados en Atención de Salud , Relaciones Profesional-Paciente , Religión y Psicología , Adulto , Anciano , Enfermedad Crónica/psicología , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Telomere 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. Results indicated a U-shaped relationship between religiosity and TL. Those scoring in the lowest 10% on religiosity tended to have the longest telomeres (5743 bp ± 367 vs. 5595 ± 383, p = 0.069). However, among the 90% of caregivers who were at least somewhat religious, religiosity was significantly and positively related to TL after controlling for covariates (B = 1.74, SE = 0.82, p = 0.034). Whereas nonreligious caregivers have relatively long telomeres, we found a positive relationship between religiosity and TL among those who are at least somewhat religious.
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Cuidadores/psicología , Religión y Psicología , Estrés Psicológico/psicología , Telómero/genética , Adulto , Anciano , Femenino , Humanos , Los Angeles , Persona de Mediana Edad , North Carolina , Reacción en Cadena en Tiempo Real de la Polimerasa , Estrés Psicológico/genética , Acortamiento del Telómero/genética , Acortamiento del Telómero/fisiologíaRESUMEN
BACKGROUND: 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. Religiosity was assessed at baseline using a 29-item scale composed of religious importance, individual religious practices, intrinsic religiosity, and daily spiritual experiences. Mixed effects growth curve models were used to compare the effects of treatment group on trajectory of change in optimism. RESULTS: In the intention-to-treat analysis, both RCBT and SCBT increased optimism over time, although there was no significant difference between treatment groups (B = -0.75, SE = 0.57, t = -1.33, P = .185). Analyses in the highly religious and in the per protocol analysis indicated similar results. Higher baseline religiosity predicted an increase in optimism over time (B = 0.07, SE = 0.02, t = 4.12, P < .0001), and higher baseline optimism predicted a faster decline in depressive symptoms over time (B = -0.61, SE = 0.10, t = -6.30, P < .0001), both independent of treatment group. CONCLUSIONS: RCBT and SCBT are equally effective in increasing optimism in persons with MDD and chronic medical illness. While baseline religiosity does not moderate this effect, religiosity predicts increases in optimism over time independent of treatment group.