243 research outputs found

    Untangling intra- and interspecific effects on body size clines reveals divergent processes structuring convergent patterns in Anolis lizards

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    Bergmann’s rule—the tendency for body size to increase in colder environments—remains controversial today, despite 150 years of research. Considerable debate has revolved around whether the rule applies within or among species. However, this debate has generally not considered that clade-level relationships are caused by both intra- and interspecific effects. In this article, we implement a novel approach that allows for the separation of intra- and interspecific components of trait-environment relationships.We apply this approach to body size clines in two Caribbean clades of Anolis lizards and discover that their similar body size gradients are constructed in very different ways. We find inverse Bergmann’s clines—high elevation lizards are smaller bodied—for both the cybotes clade on Hispaniola and the sagrei clade on Cuba. However, on Hispaniola, the inverse cline is driven by interspecific differences, whereas intraspecific variation is responsible for the inverse cline on Cuba. Our results suggest that similar body size clines can be constructed through differing evolutionary and ecological processes, namely, through local adaptation or phenotypic plasticity (intraspecific clines) and/or size-ordered spatial sorting (interspecific clines). We propose that our approach can help integrate a divided research program by focusing on how the combined effects of intra- and interspecific processes can enhance or erode clade-level relationships at large biogeographic scales

    The Act of Participating or Not: Institutional, Personal Discourses and Teacher Development

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    This study investigated how a small group of part-time, non-tenured language teachers, at a public university in central Mexico, responded to the opportunity of publishing their first research article. Based upon a qualitative study we explore the teachers’ discourses and the institution’s to understand the teachers’ positions towards this research project and how these teachers see their future teacher development within a specific context they share.  The purpose of the project was to encourage nontenured teachers who, within the institution, have limited opportunities and financial support to develop as researchers. The latter is based on the reality that throughout Mexico as well as other parts of the world and within many disciplines, academic publishing is a strategy used to measure professional development among university teachers. Findings suggest that carrying out research and publishing are not participants’ first priorities despite their interest in gaining tenure

    High-temperature deformation of delta-processed Inconel 718

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    © 2017 Elsevier B.V. The hot-flow behavior of Inconel 718 subjected to delta processing (DP) was analyzed. Hot compression tests were subsequently performed at 960 °C and 1020 °C at the four different strain rates of 0.001, 0.01, 0.1, and 1 s-1. The two deformation temperatures were located below and above the d-solvus of IN718 respectively. Microstructural characterization was performed by means of optical (OM) and scanning electron microscopy (SEM). The high temperature deformation results in the fragmentation of the existing d-phase by means of partial dissolution and/or deformation, leading to an improved grain size control. A classic dynamic recrystallization (DRX) behavior was observed in the flow curves, which is typical of low-medium stacking fault energy (SFE) alloys. This flow behavior was modeled according to various approaches. Peak stress modeling was performed using two different approaches, referred to as ‘apparent’ and ‘physically-based’. The hot-flow behavior before the peak stress was modeled according to the Estrin-Mecking-Bergstrom approach, with Avrami kinetics employed to describe the DRX behavior.Peer ReviewedPostprint (author's final draft

    Analytical performance of Four Polymerase Chain Reaction (PCR) and real time PCR (qPCR) assays for the detection of six Leishmania species DNA in Colombia

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    Leishmaniasis comprises a spectrum of parasitic diseases caused by protozoans of the genus Leishmania. Molecular tools have been widely employed for the detection of Leishmania due to its high sensitivity and specificity. However, the analytical performance of molecular platforms as PCR and real time PCR (qPCR) including a wide variety of molecular markers has never been evaluated. Herein, the aim was to evaluate the analytical performance of 4 PCR-based assays (designed on four different targets) and applied on conventional and real-time PCR platforms. We evaluated the analytical performance of conventional PCR and real time PCR, determining exclusivity and inclusivity, Anticipated Reportable Range (ARR), limit of detection (LoD) and accuracy using primers directed to kDNA, HSP70, 18S and ITS-1 targets. We observed that the kDNA was the most sensitive but does not meet the criterion of exclusivity. The HSP70 presented a higher LoD in conventional PCR and qPCR in comparison with the other markers (1 × 101 and 1 × 10-1 equivalent parasites/mL respectively) and had a higher coefficient of variation in qPCR. No statistically significant differences were found between the days of the test with the four molecular markers. The present study revealed that the 18S marker presented the best performance in terms of analytical sensitivity and specificity for the qPCR in the species tested (species circulating in Colombia). Therefore, we recommend to explore the analytical and diagnostic performance in future studies using a broader number of species across America. © 2017 LeĂłn, Muñoz, HernĂĄndez, Ayala, FlĂłrez, TeherĂĄn, Cubides and RamĂ­rez

    Controlling the Phase Segregation in Mixed Halide Perovskites through Nanocrystal Size

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    Mixed halide perovskites are one of the promising candidates in developing solar cells and light-emitting diodes (LEDs), among other applications, because of their tunable optical properties. Nonetheless, photoinduced phase segregation, by formation of segregated Br-rich and I-rich domains, limits the overall applicability. We tracked the phase segregation with increasing crystalline size of CsPbBr3–xIx and their photoluminescence under continuous-wave laser irradiation (405 nm, 10 mW cm–2) and observed the occurrence of the phase segregation from the threshold size of 46 ± 7 nm. These results have an outstanding agreement with the diffusion length (45.8 nm) calculated also experimentally from the emission lifetime and segregation rates. Furthermore, through Kelvin probe force microscopy, we confirmed the correlation between the phase segregation and the reversible halide ion migration among grain centers and boundaries. These results open a way to achieve segregation-free mixed halide perovskites and improve their performances in optoelectronic devices

    The GALEX Arecibo SDSS survey: III. Evidence for the Inside-Out Formation of Galactic Disks

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    We analyze a sample of galaxies with stellar masses greater than 1010M⊙10^{10} M_{\odot} and with redshifts in the range 0.025<z<0.050.025<z<0.05 for which HI mass measurements are available from the GALEX Arecibo SDSS Survey (GASS) or from the Arecibo Legacy Fast ALFA survey (ALFALFA). At a given value of M∗M_*, our sample consists primarily of galaxies that are more HI-rich than average. We constructed a series of three control samples for comparison with these HI-rich galaxies. As expected, HI-rich galaxies differ strongly from galaxies of same stellar mass that are selected without regard to HI content. The majority of these differences are attributable to the fact that galaxies with more gas are bluer and more actively star-forming. In order to identify those galaxy properties that are causally connected with HI content, we compare results derived for the HI sample with those derived for galaxies matched in stellar mass, size and NUV-rr colour. The only photometric property that is clearly attributable to increasing HI content, is the colour gradient of the galaxy. Galaxies with larger HI fractions have bluer, more actively star-forming outer disks compared to the inner part of the galaxy. HI-rich galaxies also have larger gg-band radii compared to ii-band radii. Our results are consistent with the "inside-out" picture of disk galaxy formation, which has commonly served as a basis for semi-analytic models of the formation of disks in the context of Cold Dark Matter cosmologies. The lack of any intrinsic connection between HI fraction and galaxy asymmetry suggests that gas is accreted smoothly onto the outer disk.Comment: 18 pages, 20 figures. Accepted for publication in MNRAS. GASS publications and released data can be found at http://www.mpa-garching.mpg.de/GASS/index.ph

    A contemporary picture of enterococcal endocarditis

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    BACKGROUND: Enterococcal endocarditis (EE) is a growing entity in Western countries. However, quality data from large studies is lacking. OBJECTIVES: The purpose of this study was to describe the characteristics and analyze the prognostic factors of EE in the GAMES cohort. METHODS: This was a post hoc analysis of a prospectively collected cohort of patients from 35 Spanish centers from 2008 to 2016. Characteristics and outcomes of 516 cases of EE were compared with those of 3,308 cases of nonenterococcal endocarditis (NEE). Logistic regression and Cox proportional hazards regression analysis were performed to investigate risk factors for in-hospital and 1-year mortality, as well as relapses. RESULTS: Patients with EE were significantly older; more frequently presented chronic lung disease, chronic heart failure, prior endocarditis, and degenerative valve disease; and had higher median age-adjusted Charlson score. EE more frequently involved the aortic valve and prosthesis (64.3% vs. 46.7%; p < 0.001; and 35.9% vs. 28.9%; p = 0.002, respectively) but less frequently pacemakers/defibrillators (1.5% vs. 10.5%; p < 0.001), and showed higher rates of acute heart failure (45% vs. 38.3%; p = 0.005). Cardiac surgery was less frequently performed in EE (40.7% vs. 45.9%; p = 0.024). No differences in in-hospital and 1-year mortality were found, whereas relapses were significantly higher in EE (3.5% vs. 1.7%; p = 0.035). Increasing Charlson score, LogEuroSCORE, acute heart failure, septic shock, and paravalvular complications were risk factors for mortality, whereas prior endocarditis was protective and persistent bacteremia constituted the sole risk factor for relapse. CONCLUSIONS: Besides other baseline and clinical differences, EE more frequently affects prosthetic valves and less frequently pacemakers/defibrillators. EE presents higher rates of relapse than NEE. Copyright © 2020 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved. KEYWORDS: enterococci; epidemiology; heart failure; infective endocarditis; prosthetic valves; relapse

    2016 Expert consensus document on prevention, diagnosis and treatment of short-term peripheral venous catheter-related infections in adults

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    AbstractThe use of endovascular catheters is a routine practice in secondary and tertiary care level hospitals. The short-term use of peripheral catheters has been found to be associated with the risk of nosocomial bacteraemia, resulting in morbidity and mortality. Staphylococcus aureus is mostly associated with peripheral catheter insertion. This Consensus Document has been prepared by a panel of experts of the Spanish Society of Cardiovascular Infections, in cooperation with experts from the Spanish Society of Internal Medicine, Spanish Society of Chemotherapy, and the Spanish Society of Thoracic-Cardiovascular Surgery, and aims to define and establish guidelines for the management of short duration peripheral vascular catheters. The document addresses the indications for insertion, catheter maintenance, registering, diagnosis and treatment of infection, indications for removal, as well as placing an emphasis on continuous education as a drive toward quality. Implementation of these guidelines will allow uniformity in use, thus minimizing the risk of infections and their complications
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