1,309 research outputs found

    CANDELS Sheds Light on the Environmental Quenching of Low-mass Galaxies

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    We investigate the environmental quenching of galaxies, especially those with stellar masses (M*)<109.5M<10^{9.5} M_\odot, beyond the local universe. Essentially all local low-mass quenched galaxies (QGs) are believed to live close to massive central galaxies, which is a demonstration of environmental quenching. We use CANDELS data to test {\it whether or not} such a dwarf QG--massive central galaxy connection exists beyond the local universe. To this purpose, we only need a statistically representative, rather than a complete, sample of low-mass galaxies, which enables our study to z1.5z\gtrsim1.5. For each low-mass galaxy, we measure the projected distance (dprojd_{proj}) to its nearest massive neighbor (M*>1010.5M>10^{10.5} M_\odot) within a redshift range. At a given redshift and M*, the environmental quenching effect is considered to be observed if the dprojd_{proj} distribution of QGs (dprojQd_{proj}^Q) is significantly skewed toward lower values than that of star-forming galaxies (dprojSFd_{proj}^{SF}). For galaxies with 108M<M<1010M10^{8} M_\odot < M* < 10^{10} M_\odot, such a difference between dprojQd_{proj}^Q and dprojSFd_{proj}^{SF} is detected up to z1z\sim1. Also, about 10\% of the quenched galaxies in our sample are located between two and four virial radii (RVirR_{Vir}) of the massive halos. The median projected distance from low-mass QGs to their massive neighbors, dprojQ/RVird_{proj}^Q / R_{Vir}, decreases with satellite M* at M109.5MM* \lesssim 10^{9.5} M_\odot, but increases with satellite M* at M109.5MM* \gtrsim 10^{9.5} M_\odot. This trend suggests a smooth, if any, transition of the quenching timescale around M109.5MM* \sim 10^{9.5} M_\odot at 0.5<z<1.00.5<z<1.0.Comment: 8 pages, 5 figures. ApJL accepted. Typos correcte

    The p75 Neurotrophin Receptor Mediates Neuronal Apoptosis and Is Essential for Naturally Occurring Sympathetic Neuron Death

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    Abstract. To determine whether the p75 neurotrophin receptor (p75NTR) plays a role in naturally occurring neuronal death, we examined neonatal sympathetic neurons that express both the TrkA tyrosine kinase receptor and p75NTR. When sympathetic neuron survival is maintained with low quantities of NGF or KCl, the neurotrophin brain-derived neurotrophic factor (BDNF), which does not activate Trk receptors on sympathetic neurons, causes neuronal apoptosis and increased phosphorylation of c-jun. Function-blocking antibody studies indicate that this apoptosis is due to BDNF-mediated activation of p75NTR. To determine the physiological relevance of these culture findings, we examined sympathetic neurons in BDNF−/− and p75NTR−/− mice. In BDNF−/− mice, sympathetic neuron number is increased relative to BDNF+/+ littermates, and in p75NTR−/− mice, the normal period of sympathetic neuron death does not occur, with neuronal attrition occurring later in life. This deficit in apoptosis is intrinsic to sympathetic neurons, since cultured p75NTR−/− neurons die more slowly than do their wild-type counterparts. Together, these data indicate that p75NTR can signal to mediate apoptosis, and that this mechanism is essential for naturally occurring sympathetic neuron death

    Interacción entre clima y ocupación humana en la configuración del paisaje vegetal del Parque Nacional de Aigüestortes i Estany de Sant Maurici a lo largo de los últimos 15.000 años

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    The vegetation of the National Park of Aigüestortes i Estany de St Maurici is the result of an interaction between climate, plant community dynamics and the human occupation of the territory. The OCUPAproject aimed to reconstruct this interaction across the last millennia combining methods from palaeoecology and archaeology. The study focused primarily on the Sant Nicolau valley and built on the multidisciplinary analysis of the sedimentary archive of two lakes (Llebreta and Redó) and a number of archaeological sites located in shelters and outdoors. There is archaeological evidence of human presencesince 9000 yr cal BP, and a continuous record since 7500 yr cal BP. At early stages, humans transformed the surroundings of the shelters occupied and lithic tools indicate contacts with locations far away (i.e.,the Ebro plains). Since more than 3000 years ago, there has been human impact on the vegetation withoutinterruption until present. Initially, the impacts were mostly related to livestock: use of fire to open grazing lands, soil erosion and, during the medieval period, forestry and eutrophication of lakes. The agriculture impact in the lower part of the valley (e.g., Llebreta) occurred about 2100 yr ago, although some cereal grains and tools for harvesting have been found for the Neolithic. In the medieval period, the impact was higher than during the last centuries. In general, the changes in the human land use approximately follow the major changes in climate, but the specific causal link is likely related to the social and cultural dynamics of a broader territory since the Neolithic

    MARIBNO project: Structure of the NorthWest Iberian margin: influence of inherited tectonics in the Alpine extension and inversion

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    X Congreso Geológico de España, 5-7 Julio 2021, Vitoria - GasteizLa zona noroeste de Iberia reúne rasgos geológicos excepcionales relacionados con el desarrollo de un margen continental hiperextendido cerca de un punto triple y la posterior inversión tectónica parcial. Es una zona de gran interés para el estudio del papel de la herencia tectónica y la posterior inversión en márgenes continentales extensionales, pero hay un gran déficit de información. Todo esto sienta las bases del proyecto anfibio MARIBNO (PGC2018-095999-B-I00) donde a lo largo de 2021 y 2022 se adquirirán sísmica marina de reflexión multicanal 2D (~4000 km), sísmica de gran ángulo en 3 transectos tierra-mar (~600 km), batimetría multihaz, grav-mag y sísmica de alta resolución. Se complementará en tierra con adquisición de datos grav-mag y varias campañas de cartografía geológica. Los objetivos se centran en el estudio de la estructura cortical, el control tectónico ejercido por estructuras previas a las etapas alpinas y la cartografía y caracterización de los dominios corticales aunando criterios geológicos y geofísicos.Todo esto sienta las bases del proyecto anfibio MARIBNO (PGC2018-095999-B-I00) donde a lo largo de 2021 y 2022 se adquirirán sísmica marina de reflexión multicanal 2D (~4000 km), sísmica de gran ángulo en 3 transectos tierra-mar (~600 km), batimetría multihaz, grav-mag y sísmica de alta resolución

    A transcriptome-wide association study among 97,898 women to identify candidate susceptibility genes for epithelial ovarian cancer risk

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    Large-scale genome-wide association studies (GWAS) have identified approximately 35 loci associated with epithelial ovarian cancer (EOC) risk. The majority of GWAS-identified disease susceptibility variants are located in non-coding regions, and causal genes underlying these associations remain largely unknown. Here we performed a transcriptome-wide association study to search for novel genetic loci and plausible causal genes at known GWAS loci. We used RNA sequencing data (68 normal ovarian-tissue samples from 68 individuals and 6,124 cross-tissue samples from 369 individuals) and high-density genotyping data from European descendants of the Genotype-Tissue Expression (GTEx V6) project to build ovarian and cross-tissue models of genetically regulated expression using elastic net methods. We evaluated 17,121 genes for their cis-predicted gene expression in relation to EOC risk using summary statistics data from GWAS of 97,898 women, including 29,396 EOC cases. With a Bonferroni-corrected significance level of P<2.2×10-6, we identified 35 genes including FZD4 at 11q14.2 (Z=5.08, P=3.83×10-7, the cross-tissue model; 1 Mb away from any GWAS-identified EOC risk variant), a potential novel locus for EOC risk. All other 34 significantly-associated genes were located within 1 Mb of known GWAS-identified loci, including 23 genes at 6 loci not previously linked to EOC risk. Upon conditioning on nearby known EOC GWAS-identified variants, the associations for 31 genes disappeared and 3 genes remained (P<1.47 x 10-3). These data identify one novel locus (FZD4) and 34 genes at 13 known EOC risk loci associated with EOC risk, providing new insights into EOC carcinogenesis

    Predicting attitudinal and behavioral responses to COVID-19 pandemic using machine learning

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    At the beginning of 2020, COVID-19 became a global problem. Despite all the efforts to emphasize the relevance of preventive measures, not everyone adhered to them. Thus, learning more about the characteristics determining attitudinal and behavioral responses to the pandemic is crucial to improving future interventions. In this study, we applied machine learning on the multinational data collected by the International Collaboration on the Social and Moral Psychology of COVID-19 (N = 51,404) to test the predictive efficacy of constructs from social, moral, cognitive, and personality psychology, as well as socio-demographic factors, in the attitudinal and behavioral responses to the pandemic. The results point to several valuable insights. Internalized moral identity provided the most consistent predictive contribution—individuals perceiving moral traits as central to their self-concept reported higher adherence to preventive measures. Similar results were found for morality as cooperation, symbolized moral identity, self-control, open-mindedness, and collective narcissism, while the inverse relationship was evident for the endorsement of conspiracy theories. However, we also found a non-neglible variability in the explained variance and predictive contributions with respect to macro-level factors such as the pandemic stage or cultural region. Overall, the results underscore the importance of morality-related and contextual factors in understanding adherence to public health recommendations during the pandemic.Peer reviewe

    National identity predicts public health support during a global pandemic (vol 13, 517, 2022) : National identity predicts public health support during a global pandemic (Nature Communications, (2022), 13, 1, (517), 10.1038/s41467-021-27668-9)

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    Publisher Copyright: © The Author(s) 2022.In this article the author name ‘Agustin Ibanez’ was incorrectly written as ‘Augustin Ibanez’. The original article has been corrected.Peer reviewe
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