1,893 research outputs found

    Symbiotic stars in X-rays IV. XMM-Newton, Swift, and TESS observations

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    White dwarf symbiotic binaries are detected in X-rays with luminosities in the range of 1030–1034 ergs s−1. Their X-ray emission ariseseither from the accretion disk boundary layer, from a region where the winds from both components collide, or from nuclear burningon the surface of the white dwarf (WD). In our continuous effort to identify X-ray-emitting symbiotic stars, we studied four systemsusing observations from the Neil Gehrels Swift Observatory and XMM-Newton satellites in X-rays and from Transiting ExoplanetSurvey Satellite (TESS) in the optical. The X-ray spectra were fit with absorbed optically thin thermal plasma models that are eithersingle- or multitemperature with kT < 8 keV for all targets. Based on the characteristics of their X-ray spectra, we classified BD Camas possible β-type, V1261 Ori and CD −27 8661 as δ-type, and confirmed NQ Gem as β/δ-type. The δ-type X-ray emission most likelyarises from the boundary layer of the accretion disk, while in the case of BD Cam, its mostly soft emission originates from shocks,possibly between the red giant and WD and disk winds. In general, we find that the observed X-ray emission is powered by accretionat a low accretion rate of about 10−11 M yr−1. The low ratio of X-ray to optical luminosities, however indicates that the accretion-diskboundary layer is mostly optically thick and tends to emit in the far or extreme UV. The detection of flickering in optical data providesevidence of the existence of an accretion disk.Fil: de Jesus Lima, Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Luna, Gerardo Juan Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Hurlingham; ArgentinaFil: Mukai, K.. National Aeronautics and Space Administration; Estados Unidos. University of Maryland; Estados UnidosFil: Oliveira, A. S.. Universidade do Vale do Paraíba; BrasilFil: Sokoloski, J. L.. Columbia University; Estados UnidosFil: Walter, F. M.. State University of New York; Estados UnidosFil: Palivanas, N.. Universidade do Vale do Paraíba; BrasilFil: Nuñez, Natalia Edith. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; ArgentinaFil: Souza, R. R.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Araujo, R. A. N.. Instituto de Ciencia y Tecnologia ; Universidade Estadual Paulista Julio de Mesquita Filho

    Caspase-8 mediates inflammation and disease in rodent malaria

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    Earlier studies indicate that either the canonical or non-canonical pathways of inflammasome activation have a limited role on malaria pathogenesis. Here, we report that caspase-8 is a central mediator of systemic inflammation, septic shock in the Plasmodium chabaudi-infected mice and the P. berghei-induced experimental cerebral malaria (ECM). Importantly, our results indicate that the combined deficiencies of caspases-8/1/11 or caspase-8/gasdermin-D (GSDM-D) renders mice impaired to produce both TNFalpha and IL-1beta and highly resistant to lethality in these models, disclosing a complementary, but independent role of caspase-8 and caspases-1/11/GSDM-D in the pathogenesis of malaria. Further, we find that monocytes from malaria patients express active caspases-1, -4 and -8 suggesting that these inflammatory caspases may also play a role in the pathogenesis of human disease

    Mutations in TP53 and JAK2 are independent prognostic biomarkers in B-cell precursor acute lymphoblastic leukaemia

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    [EN]Background: In B-cell precursor acute lymphoblastic leukaemia (B-ALL), the identification of additional genetic alterations associated with poor prognosis is still of importance. We determined the frequency and prognostic impact of somatic mutations in children and adult cases with B-ALL treated with Spanish PETHEMA and SEHOP protocols. Methods: Mutational status of hotspot regions of TP53, JAK2, PAX5, LEF1, CRLF2 and IL7R genes was determined by next-generation deep sequencing in 340 B-ALL patients (211 children and 129 adults). The associations between mutation status and clinicopathological features at the time of diagnosis, treatment outcome and survival were assessed. Univariate and multivariate survival analyses were performed to identify independent prognostic factors associated with overall survival (OS), event-free survival (EFS) and relapse rate (RR). Results: A mutation rate of 12.4% was identified. The frequency of adult mutations was higher (20.2% vs 7.6%, P=0.001). TP53 was the most frequently mutated gene (4.1%), followed by JAK2 (3.8%), CRLF2 (2.9%), PAX5 (2.4%), LEF1 (0.6%) and IL7R (0.3%). All mutations were observed in B-ALL without ETV6-RUNX1 (P=0.047) or BCR-ABL1 fusions (P<0.0001). In children, TP53mut was associated with lower OS (5-year OS: 50% vs 86%, P=0.002) and EFS rates (5-year EFS: 50% vs 78.3%, P=0.009) and higher RR (5-year RR: 33.3% vs 18.6% P=0.037), and was independently associated with higher RR (hazard ratio (HR)=4.5; P=0.04). In adults, TP53mut was associated with a lower OS (5-year OS: 0% vs 43.3%, P=0.019) and a higher RR (5-year RR: 100% vs 61.4%, P=0.029), whereas JAK2mut was associated with a lower EFS (5-year EFS: 0% vs 30.6%, P=0.035) and a higher RR (5-year RR: 100% vs 60.4%, P=0.002). TP53mut was an independent risk factor for shorter OS (HR=2.3; P=0.035) and, together with JAK2mut, also were independent markers of poor prognosis for RR (TP53mut: HR=5.9; P=0.027 and JAK2mut: HR=5.6; P=0.036). Conclusions: TP53mut and JAK2mut are potential biomarkers associated with poor prognosis in B-ALL patients.European Commision (EC). Funding FP7/SP1/HEALTH. Project Code: 30624

    Assessing the Psychedelic "After-Glow" in Ayahuasca Users : Post-Acute Neurometabolic and Functional Connectivity Changes Are Associated with Enhanced Mindfulness Capacities

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    Ayahuasca is a plant tea containing the psychedelic 5-HT agonist N,N -dimethyltryptamine and harmala monoamine-oxidase inhibitors. Acute administration leads to neurophysiological modifications in brain regions of the default mode network, purportedly through a glutamatergic mechanism. Post-acutely, ayahuasca potentiates mindfulness capacities in volunteers and induces rapid and sustained antidepressant effects in treatment-resistant patients. However, the mechanisms underlying these fast and maintained effects are poorly understood. Here, we investigated in an open-label uncontrolled study in 16 healthy volunteers ayahuasca-induced post-acute neurometabolic and connectivity modifications and their association with mindfulness measures. Using 1 H-magnetic resonance spectroscopy and functional connectivity, we compared baseline and post-acute neurometabolites and seed-to-voxel connectivity in the posterior and anterior cingulate cortex after a single ayahuasca dose. Magnetic resonance spectroscopy showed post-acute reductions in glutamate+glutamine, creatine, and N-acetylaspartate+N-acetylaspartylglutamate in the posterior cingulate cortex. Connectivity was increased between the posterior cingulate cortex and the anterior cingulate cortex, and between the anterior cingulate cortex and limbic structures in the right medial temporal lobe. Glutamate+glutamine reductions correlated with increases in the "nonjudging" subscale of the Five Facets Mindfulness Questionnaire. Increased anterior cingulate cortex-medial temporal lobe connectivity correlated with increased scores on the self-compassion questionnaire. Post-acute neural changes predicted sustained elevations in nonjudging 2 months later. These results support the involvement of glutamate neurotransmission in the effects of psychedelics in humans. They further suggest that neurometabolic changes in the posterior cingulate cortex, a key region within the default mode network, and increased connectivity between the anterior cingulate cortex and medial temporal lobe structures involved in emotion and memory potentially underlie the post-acute psychological effects of ayahuasca

    Evaluación del estado de conservación de los bosques montanos en los Andes tropicales

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    Los Andes tropicales constituyen una región única con una alta diversidad de hábitats, producto de complejos gradientes espaciales y ambientales. Los bosques montanos de esta región son considerados como una prioridad global de conservación, debido principalmente a su elevada riqueza biológica y de endemismos. Sin embargo su biodiversidad es de las menos conocidas de toda la región tropical, aunque se reconoce la amplia gama de servicios ambientales que prestan, incluyendo la regulación del clima regional y la captura y almacenamiento de carbono. Este artículo ofrece una perspectiva general del estado de conservación de los bosques montanos tropicales andinos y de los retos que esta implica. Asimismo, proporciona información sobre sus amenazas, identificando aquéllas que con mayor probabilidad sean responsables de aumentar el riesgo de extinción de especies. Se resalta la necesidad de disponer de más información sobre el estado de conservación de las especies para identificar las futuras prioridades de conservación en la región. La reciente iniciativa de la "Lista Roja y planeación para la conservación de especies de árboles montanos de los Andes Tropicales", formada por delegados de varios países de la región, constituirá una sólida base para el desarrollo y enfoque de políticas y respuestas de manejo dirigidas a la reducción de la deforestación y pérdida de especies en estos bosques, incluyendo acciones para promover la creación de áreas protegidas, restauración forestal y manejo forestal sostenible.The tropical Andes is a unique region with high habitat diversity, resulting from complex climatic and spatial gradients. Andean montane forests are currently a major global conservation priority owing to their high species richness and high level of endemism. Nonetheless they are considered one of the least known ecosystems in the tropics, but the breath of ecosystem services that these forests provide, including the regulation of regional climate and the capture and storage of carbon, is widely recognised. This article presents an overview of the conservation status of tropical Andean montane forests and the challenges it entails. It also provides information on threats, including the identification of those that are most likely to be responsible for increasing the extinction risk for many species. It highlights the need for acquiring more information on the conservation status of species as to identify future priorities for conservation in the region. The recent initiative "Red List and conservation planning for montane tree species of the Tropical Andes," made of delegates from several countries in the region, will provide a solid basis for developing policies and managing responses aimed at reducing deforestation and species loss in these forests, including actions to promote the creation of protected areas, forest restoration and sustainable forest management.Bournemouth UniversityBotanic Gardens Conservation InternationalBanco Santande

    AVASUS’ Contributions to Promoting Lifelong Learning in Health: Toward Achieving the SDGs and Strengthening Global Health Security

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    The Virtual Learning Environment of the Brazilian Health System (AVASUS) was developed by the Laboratory for Technological Innovation in Health (LAIS) and the Secretariat of Distance Education (SEDIS) at the Federal University of Rio Grande do Norte (UFRN) in partnership with Brazil’s Ministry of Health (MoH). AVASUS provides open educational resources in the health field and has emerged as the third largest platform for massive health education globally, with more than one million students. Among the various learning pathways AVASUS offers, some specifically focus on meeting the educational needs to address public health emergencies and overlooked health contexts. The main argument in this study is that technology-mediated lifelong learning in health is an effective strategy for achieving the Sustainable Development Goals (SDGs) of the 2030 Agenda. This chapter analyzes the pathways related to COVID-19, syphilis, and prison health, focusing on the contributions towards achieving SDGs 3, 4, 5, 10, 11, 16, and 17 and fulfilling the Global Health Security Agenda. Our analysis revealed two key findings. Lifelong learning in health (i) prompts decision-making on public health policies and (ii) contributes towards implementing the SDGs. Ultimately, AVASUS should be recognized as a tool to improve health services and support policy-making

    Psycho-social factors associated with mental resilience in the Corona lockdown.

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    The SARS-CoV-2 pandemic is not only a threat to physical health but is also having severe impacts on mental health. Although increases in stress-related symptomatology and other adverse psycho-social outcomes, as well as their most important risk factors have been described, hardly anything is known about potential protective factors. Resilience refers to the maintenance of mental health despite adversity. To gain mechanistic insights about the relationship between described psycho-social resilience factors and resilience specifically in the current crisis, we assessed resilience factors, exposure to Corona crisis-specific and general stressors, as well as internalizing symptoms in a cross-sectional online survey conducted in 24 languages during the most intense phase of the lockdown in Europe (22 March to 19 April) in a convenience sample of N = 15,970 adults. Resilience, as an outcome, was conceptualized as good mental health despite stressor exposure and measured as the inverse residual between actual and predicted symptom total score. Preregistered hypotheses (osf.io/r6btn) were tested with multiple regression models and mediation analyses. Results confirmed our primary hypothesis that positive appraisal style (PAS) is positively associated with resilience (p < 0.0001). The resilience factor PAS also partly mediated the positive association between perceived social support and resilience, and its association with resilience was in turn partly mediated by the ability to easily recover from stress (both p < 0.0001). In comparison with other resilience factors, good stress response recovery and positive appraisal specifically of the consequences of the Corona crisis were the strongest factors. Preregistered exploratory subgroup analyses (osf.io/thka9) showed that all tested resilience factors generalize across major socio-demographic categories. This research identifies modifiable protective factors that can be targeted by public mental health efforts in this and in future pandemics

    Local hydrological conditions influence tree diversity and composition across the Amazon basin

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    Tree diversity and composition in Amazonia are known to be strongly determined by the water supplied by precipitation. Nevertheless, within the same climatic regime, water availability is modulated by local topography and soil characteristics (hereafter referred to as local hydrological conditions), varying from saturated and poorly drained to well-drained and potentially dry areas. While these conditions may be expected to influence species distribution, the impacts of local hydrological conditions on tree diversity and composition remain poorly understood at the whole Amazon basin scale. Using a dataset of 443 1-ha non-flooded forest plots distributed across the basin, we investigate how local hydrological conditions influence 1) tree alpha diversity, 2) the community-weighted wood density mean (CWM-wd) – a proxy for hydraulic resistance and 3) tree species composition. We find that the effect of local hydrological conditions on tree diversity depends on climate, being more evident in wetter forests, where diversity increases towards locations with well-drained soils. CWM-wd increased towards better drained soils in Southern and Western Amazonia. Tree species composition changed along local soil hydrological gradients in Central-Eastern, Western and Southern Amazonia, and those changes were correlated with changes in the mean wood density of plots. Our results suggest that local hydrological gradients filter species, influencing the diversity and composition of Amazonian forests. Overall, this study shows that the effect of local hydrological conditions is pervasive, extending over wide Amazonian regions, and reinforces the importance of accounting for local topography and hydrology to better understand the likely response and resilience of forests to increased frequency of extreme climate events and rising temperatures
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