211 research outputs found

    Environmentally induced phenotypic variation in wild yellow-bellied marmots

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    We thank all the marmoteers who helped in data collection and 2 anonymous reviewers who helped us to clarify our message. AM-C was supported by a Fulbright Fellowship, and JGAM was supported by Fond Québécois de Recherche sur la Nature et les Technologies. KBA was supported by the National Science Foundation between 1962 and 2000. DTB was supported by the National Geographic Society, UCLA (Faculty Senate and the Division of Life Sciences), a Rocky Mountain Biological Laboratory research fellowship, and by the National Science Foundation (IDBR-0754247 and DEB-1119660 to DTB as well as DBI 0242960 and 0731346 to the Rocky Mountain Biological Laboratory).Peer reviewedPostprin

    Modeling the Dynamics of Long-Term Variability of Hydroclimatic Processes

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    The stochastic analysis, modeling, and simulation of climatic and hydrologic processes such as precipitation, streamflow, and sea surface temperature have usually been based on assumed stationarity or randomness of the process under consideration. However, empirical evidence of many hydroclimatic data shows temporal variability involving trends, oscillatory behavior, and sudden shifts. While many studies have been made for detecting and testing the statistical significance of these special characteristics, the probabilistic framework for modeling the temporal dynamics of such processes appears to be lacking. In this paper a family of stochastic models that can be used to capture the dynamics of abrupt shifts in hydroclimatic time series is proposed. The applicability of such ‘‘shifting mean models’ ’ are illustrated by using time series data of annual Pacific decadal oscillation (PDO) indices and annual streamflows of the Niger River. 1

    Nature and chemical abundances of a sample of Lyman-α emitter objects at high redshift

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    We built a grid of photoionization models and compiled already available observational emission line intensities (1000 53. Values for C/O abundance ratio derived for the LAEs seem to be consistent with those derived for local star forming objects with similar metallicities, while an overabundance of N/O was found for most of the LAEs.Instituto de Astrofísica de La Plat

    Nature and chemical abundances of a sample of Lyman-α emitter objects at high redshift

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    We built a grid of photoionization models and compiled already available observational emission line intensities (1000 53. Values for C/O abundance ratio derived for the LAEs seem to be consistent with those derived for local star forming objects with similar metallicities, while an overabundance of N/O was found for most of the LAEs.Instituto de Astrofísica de La Plat

    Chemical abundance of the LINER galaxy UGC 4805 with SDSS-IV MaNGA

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    Chemical abundance determinations in Low-Ionization Nuclear Line Regions (LINERs) are especially complex and uncertain because the nature of the ionizing source of this kind of object is unknown. In this work, we study the oxygen abundance in relation to the hydrogen abundance (O/H) of the gas phase of the UGC 4805 LINER nucleus. Optical spectroscopic data from the Mapping Nearby Galaxies (MaNGA) survey was employed to derive the O/H abundance of the UGC 4805 nucleus based on the extrapolation of the disk abundance gradient, on calibrations between O/H abundance and strong emission-lines for Active Galactic Nuclei (AGNs) as well as on photoionization models built with the Cloudy code, assuming gas accretion into a black hole (AGN) and post-Asymptotic Giant Branch (p-AGB) stars with different effective temperatures. We found that abundance gradient extrapolations, AGN calibrations, AGN and p-AGB photoionization models produce similar O/H values for the UGC 4805 nucleus and similar ionization parameter values. The study demonstrated that the methods used to estimate the O/H abundance using nuclear emission-line ratios produce reliable results, which are in agreement with the O/H values obtained from the independent method of galactic metallicity gradient extrapolation. Finally, the results from the WHAN diagram combined with the fact that the high excitation level of the gas has to be maintained at kpc scales, we suggest that the main ionizing source of the UGC 4805 nucleus probably has a stellar origin rather than an AGN.Fil: Krabbe, Angela. Universidade Do Vale Do Paraíba; BrasilFil: Oliveira, C. B.. Universidade Do Vale Do Paraíba; BrasilFil: Zinchenko, I. A.. Universitat Ulm. Faculty Of Natural Sciences. Institute Of Theoretical Physics; AlemaniaFil: Hernández Jiménez, J. A.. Universidad Andrés Bello; ChileFil: Dors, Oli L.. Universidade Do Vale Do Paraíba; BrasilFil: Hägele, Guillermo Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Cardaci, Monica Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Telles, N. R.. Universidade Do Vale Do Paraíba; Brasi

    Podoconiosis in East and West Gojam Zones, Northern Ethiopia

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    Background: Podoconiosis is a neglected tropical disease (NTD) that is prevalent in red clay soil-covered highlands of tropical Africa, Central and South America, and northern India. It is estimated that up to one million cases exist in Ethiopia. This study aimed to estimate the prevalence of podoconiosis in East and West Gojam Zones of Amhara Region in northern Ethiopia. Methodology/Principal Findings: A cross-sectional household survey was conducted in Debre Eliyas and Dembecha woredas (districts) in East and West Gojam Zones, respectively. The survey covered all 17,553 households in 20 kebeles (administrative subunits) randomly selected from the two woredas. A detailed structured interview was conducted on 1,704 cases of podoconiosis identified in the survey. Results: The prevalence of podoconiosis in the population aged 15 years and above was found to be 3.3% (95% CI, 3.2% to 3.6%). 87% of cases were in the economically active age group (15–64 years). On average, patients sought treatment five years after the start of the leg swelling. Most subjects had second (42.7%) or third (36.1%) clinical stage disease, 97.9% had mossy lesions, and 53% had open wounds. On average, patients had five episodes of acute adenolymphangitis (ALA) per year and spent a total of 90 days per year with ALA. The median age of first use of shoes and socks were 22 and 23 years, respectively. More men than women owned more than one pair of shoes (61.1% vs. 50.5%; x2 = 11.6 p = 0.001). At the time of interview, 23.6% of the respondents were barefoot, of whom about two-thirds were women. Conclusions: This study showed high prevalence of podoconiosis and associated morbidities such as ALA, mossy lesions and open wounds in northern Ethiopia. Predominance of cases at early clinical stage of podoconiosis indicates the potential for reversing the swelling and calls for disease prevention interventions

    Chemical abundances of Seyfert 2 AGNs, I: comparing oxygen abundances from distinct methods using SDSS

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    We compare the oxygen abundance (O/H) of the narrow-line regions (NLRs) of Seyfert 2 AGNs obtained through strong-line methods and from direct measurements of the electron temperature (Te-method). The aim of this study is to explore the effects of the use of distinct methods on the range of metallicity and on the mass-metallicity relation of active galactic nuclei (AGNs) at low redshifts (z<~0.4). We used the Sloan Digital Sky Survey (SDSS) and NASA/IPACExtragalactic Database (NED) to selected optical (3000Fil: Dors, Oli L.. Universidade Do Vale Do Paraiba; BrasilFil: de Freitas Rosa, Morsyleide. Universidade Do Vale Do Paraiba; BrasilFil: Amores, E. B.. Universidade Estadual de Feira de Santana; BrasilFil: Almarcha Pérez, Martha Ayelén. Instituto de Astrofísica de Andalucía - Csic; EspañaFil: Cardaci, Monica Viviana. Instituto de Astrofísica de la Plata (conicet- Universidad Nacional de la Plata); Argentina. Universidad Nacional de La Plata; ArgentinaFil: Hägele, Guillermo Federico. Universidad Nacional de La Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Armah, M.. Universidade Do Vale Do Paraiba; BrasilFil: Krabbe, A. C.. Universidade Do Vale Do Paraiba; BrasilFil: Ruiz Faúndez, Giovanni Patricio. Laboratorio Nacional de Astrofisica, Itajuba; Brasi

    Gas phase metallicity determinations in nearby AGNs with SDSS-IV MaNGA: evidence of metal poor accretion

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    We derive the metallicity (traced by the O/H abundance) of the Narrow Line Region ( NLR) of 108 Seyfert galaxies as well as radial metallicity gradients along their galaxy disks and of these of a matched control sample of no active galaxies. In view of that, observational data from the SDSS-IV MaNGA survey and strong emission-line calibrations taken from the literature were considered. The metallicity obtained for the NLRs %each Active Galactic Nucleus (AGN) was compared to the value derived from the extrapolation of the radial oxygen abundance gradient, obtained from \ion{H}{ii} region estimates along the galaxy disk, to the central part of the host galaxies. We find that, for most of the objects (80%\sim 80\,\%), the NLR metallicity is lower than the extrapolated value, with the average difference ()betweentheseestimatesrangingfrom0.16to0.30dex.Wesuggestthat) between these estimates ranging from 0.16 to 0.30 dex. We suggest that is due to the accretion of metal-poor gas to the AGN that feeds the nuclear supermassive black hole (SMBH), which is drawn from a reservoir molecular and/or neutral hydrogen around the SMBH. Additionally, we look for correlations between DD and the electron density (NeN_{\rm e}), [\ion{O}{iii}]λ\lambda5007 and Hα\alpha luminosities, extinction coefficient (AV)A_{V}) of the NLRs, as well as the stellar mass (MM_{*}) of the host galaxies. Evidences of an inverse correlation between the DD and the parameters NeN_{\rm e}, MM_{*} and AvA_{\rm v} were found

    RHAMNETIN IS A BETTER INHIBITOR OF SARS-COV-2 2’-O-METHYLTRANSFERASE THAN DOLUTEGRAVIR: A COMPUTATIONAL PREDICTION

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    Background: The 2’-O-methyltransferase is responsible for the capping of SARS-CoV-2 mRNA and consequently the evasion of the host’s immune system. This study aims at identifying prospective natural inhibitors of the active site of SARS-CoV-2 2’O-methyltransferase (2’-OMT) through an in silico approach. Materials and Method: The target was docked against a library of natural compounds obtained from edible African plants using PyRx - virtual screening software. The antiviral agent, Dolutegravir which has a binding affinity score of -8.5 kcal mol−1 with the SARS-CoV-2 2’-OMT was used as a standard. Compounds were screened for bioavailability through the SWISSADME web server using their molecular descriptors. Screenings for pharmacokinetic properties and bioactivity were performed with PKCSM and Molinspiration web servers respectively. The PLIP and Fpocket webservers were used for the binding site analyses. The Galaxy webserver was used for simulating the time-resolved motions of the apo and holo forms of the target while the MDWeb web server was used for the analyses of the trajectory data. Results: The Root-Mean-Square-Deviation (RMSD) induced by Rhamnetin is 1.656A0 as compared to Dolutegravir (1.579A0). The average B-factor induced by Rhamnetin is 113.75 while for Dolutegravir is 78.87; the Root-Mean-Square-Fluctuation (RMSF) for Rhamnetin is 0.75 and for Dolutegravir is 0.67. Also at the active site, Rhamnetin also has a binding affinity score of -9.5 kcal mol−1 and forms 7 hydrogen bonds as compared to Dolutegravir which has -8.5 kcal mol−1 and forms 4 hydrogen bonds respectively. Conclusion: Rhamnetin showed better inhibitory activity at the target’s active site than Dolutegravir

    Individual correlates of podoconiosis in areas of varying endemicity: a case-control study

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    BACKGROUND Podoconiosis is a non-filarial form of elephantiasis resulting in lymphedema of the lower legs. Previous studies have suggested that podoconiosis arises from the interplay of individual and environmental factors. Here, our aim was to understand the individual-level correlates of podoconiosis by comparing 460 podoconiosis-affected individuals and 707 unaffected controls. METHODS/PRINCIPAL FINDINGS This was a case-control study carried out in six kebeles (the lowest governmental administrative unit) in northern Ethiopia. Each kebele was classified into one of three endemicity levels: 'low' (prevalence 5%). A total of 142 (30.7%) households had two or more cases of podoconiosis. Compared to controls, the majority of the cases, especially women, were less educated (OR = 1.7, 95% CI = 1.3 to 2.2), were unmarried (OR = 3.4, 95% CI = 2.6-4.6) and had lower income (t = -4.4, p<0.0001). On average, cases started wearing shoes ten years later than controls. Among cases, age of first wearing shoes was positively correlated with age of onset of podoconiosis (r = 0.6, t = 12.5, p<0.0001). Among all study participants average duration of shoe wearing was less than 30 years. Between both cases and controls, people in 'high' and 'medium' endemicity kebeles were less likely than people in 'low' endemicity areas to 'ever' have owned shoes (OR = 0.5, 95% CI = 0.4-0.7). CONCLUSIONS Late use of shoes, usually after the onset of podoconiosis, and inequalities in education, income and marriage were found among cases, particularly among females. There were clustering of cases within households, thus interventions against podoconiosis will benefit from household-targeted case tracing. Most importantly, we identified a secular increase in shoe-wearing over recent years, which may give opportunities to promote shoe-wearing without increasing stigma among those at high risk of podoconiosis
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