2,933 research outputs found

    White dwarf and subdwarf stars in the Sloan Digital Sky Survey Data Release 14

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    White dwarfs carry information on the structure and evolution of the Galaxy, especially through their luminosity function and initial-to-final mass relation. Very cool white dwarfs provide insight into the early ages of each population. Examining the spectra of all stars with 3σ3\sigma proper motion in the Sloan Digital Sky Survey Data Release 14, we report the classification for 20 088 spectroscopically confirmed white dwarfs, plus 415 hot subdwarfs, and 311 cataclysmic variables. We obtain Teff, log g and mass for hydrogen atmosphere white dwarf stars (DAs), warm helium atmosphere white dwarfs (DBs), hot subdwarfs (sdBs and sdOs), and estimate photometric Teff for white dwarf stars with continuum spectra (DCs). We find 15793 sdAs and 447 dCs between the white dwarf cooling sequence and the main sequence, especially below Teff= 10000 K; most are likely low-mass metal-poor main sequence stars, but some could be the result of interacting binary evolution.Comment: 18 pages, 13 figure

    Asymptotics for Fermi curves: small magnetic potential

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    We consider complex Fermi curves of electric and magnetic periodic fields. These are analytic curves in C^2 that arise from the study of the eigenvalue problem for periodic Schroedinger operators. We characterize a certain class of these curves in the region of C^2 where at least one of the coordinates has "large" imaginary part. The new results in this work extend previous results in the absence of magnetic field to the case of "small" magnetic field. Our theorems can be used to show that generically these Fermi curves belong to a class of Riemann surfaces of infinite genus.Comment: 71 pages, 1 figur

    Body-bending behaviour in snakes: new records of a poorly documented defensive behaviour.

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    Se describe el comportamiento poco conocido de "Body-bending behaviour" en varias especies de culebras y se discute el mismo.Fil: França, D. P. F.. Museu de Zoologia - Usp; BrasilFil: Oliveira, I. F.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Gennari, D.. Universidade Federal do Rio Grande do Norte. Centro de Biociencias. Departamento de Boanica, Ecologia e Zoologia; BrasilFil: Rocha, B. Universidade de Sao Paulo; BrasilFil: Smith, P.. Centro Ideal; ParaguayFil: Scrocchi Manfrini, Gustavo Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Machado Filho, P. R.. Universidade de Sao Paulo; Brasi

    Quantitative Proteomic Analysis Reveals Changes in the Benchmark Corynebacterium pseudotuberculosis Biovar Equi Exoproteome after Passage in a Murine Host

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    Corynebacterium pseudotuberculosis biovar equi is the etiologic agent of ulcerative lymphangitis. To investigate proteins that could be related to the virulence of this pathogen, we combined an experimental passage process using a murine model and high-throughput proteomics with a mass spectrometry, data-independent acquisition (LC-MSE) approach to identify and quantify the proteins released into the supernatants of strain 258_equi. To our knowledge, this approach allowed characterization of the exoproteome of a C. pseudotuberculosis equi strain for the first time. Interestingly, the recovery of this strain from infected mouse spleens induced a change in its virulence potential, and it became more virulent in a second infection challenge. Proteomic screening performed from culture supernatant of the control and recovered conditions revealed 104 proteins that were differentially expressed between the two conditions. In this context, proteomic analysis of the recovered condition detected the induction of proteins involved in bacterial pathogenesis, mainly related to iron uptake. In addition, KEGG enrichment analysis showed that ABC transporters, bacterial secretion systems and protein export pathways were significantly altered in the recovered condition. These findings show that secretion and secreted proteins are key elements in the virulence and adaptation of C. pseudotuberculosis. Collectively, bacterial pathogenesis-related proteins were identified that contribute to the processes of adherence, intracellular growth and evasion of the immune system. Moreover, this study enhances our understanding of the factors that may influence the pathogenesis of C. pseudotuberculosis.Fil: Marques Da Silva, Wanderson. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas; Brasil. Institut National de la Recherche Agronomique; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Carvalho, Rodrigo D. De Oliveira. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas; BrasilFil: Dorella, Fernanda A.. Universidade Federal de Minas Gerais; BrasilFil: Folador, Edson L.. Universidade Federal da Paraíba. Centro de Biotecnologia; BrasilFil: Souza, Gustavo H. M. F.. Waters Corporation; BrasilFil: Pimenta, Adriano M. C.. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas; BrasilFil: Figueiredo, Henrique C. P.. Universidade Federal de Minas Gerais; BrasilFil: Le Loir, Yves. Institut National de la Recherche Agronomique; FranciaFil: Silva, Artur. Universidade Federal do Pará; BrasilFil: Azevedo, Vasco. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas; Brasi

    Dietary whey protein lessens several risk factors for metabolic diseases: a review

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    Obesity and type 2 diabetes mellitus (DM) have grown in prevalence around the world, and recently, related diseases have been considered epidemic. Given the high cost of treatment of obesity/DM-associated diseases, strategies such as dietary manipulation have been widely studied; among them, the whey protein diet has reached popularity because it has been suggested as a strategy for the prevention and treatment of obesity and DM in both humans and animals. Among its main actions, the following activities stand out: reduction of serum glucose in healthy individuals, impaired glucose tolerance in DM and obese patients; reduction in body weight; maintenance of muscle mass; increases in the release of anorectic hormones such as cholecystokinin, leptin, and glucagon like-peptide 1 (GLP-1); and a decrease in the orexigenic hormone ghrelin. Furthermore, studies have shown that whey protein can also lead to reductions in blood pressure, inflammation, and oxidative stress.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Univ Estadual Campinas UNICAMP, Dept Clin Med, BR-13083970 Campinas, SP, BrazilUniv São Paulo, Inst Ciencias Biomed, Dept Fisiol & Biofis, São Paulo, BrazilUniv Extremo Catarinense, Lab Bioquim & Fisiol Exercicio, Criciuma, SC, BrazilUniv Estadual Paulista UNESP, Dept Patol, Botucatu, SP, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Fisiol, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Psicobiol, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Fisiol, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Dept Psicobiol, São Paulo, BrazilWeb of Scienc

    Accurate Atmospheric Parameters at Moderate Resolution Using Spectral Indices: Preliminary Application to the MARVELS Survey

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    Studies of Galactic chemical and dynamical evolution in the solar neighborhood depend on the availability of precise atmospheric parameters (Teff, [Fe/H] and log g) for solar-type stars. Many large-scale spectroscopic surveys operate at low to moderate spectral resolution for efficiency in observing large samples, which makes the stellar characterization difficult due to the high degree of blending of spectral features. While most surveys use spectral synthesis, in this work we employ an alternative method based on spectral indices to determine the atmospheric parameters of a sample of nearby FGK dwarfs and subgiants observed by the MARVELS survey at moderate resolving power (R~12,000). We have developed three codes to automatically normalize the observed spectra, measure the equivalent widths of the indices and, through the comparison of those with values calculated with pre-determined calibrations, derive the atmospheric parameters of the stars. The calibrations were built using a sample of 309 stars with precise stellar parameters obtained from the analysis of high-resolution FEROS spectra. A validation test of the method was conducted with a sample of 30 MARVELS targets that also have reliable atmospheric parameters from high-resolution spectroscopic analysis. Our approach was able to recover the parameters within 80 K for Teff, 0.05 dex for [Fe/H] and 0.15 dex for log g, values that are lower or equal to the typical external uncertainties found between different high-resolution analyzes. An additional test was performed with a subsample of 138 stars from the ELODIE stellar library and the literature atmospheric parameters were recovered within 125 K for Teff, 0.10 dex for [Fe/H] and 0.29 dex for log g. These results show that the spectral indices are a competitive tool to characterize stars with the intermediate resolution spectra.Comment: Accepted for publication in AJ. Abstract edited to comply with arXiv standards regarding the number of character

    The Proterozoic Vazante hypogene zinc silicate district, Minas Gerais, Brazil: a review of the ore system applied to mineral exploration

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    The Proterozoic Vazante zinc silicate district in Minas Gerais, Brazil, hosts world-class hypogene willemite deposits in dolomitic rocks interbedded with siliciclastic rocks deposited in subtidal to supratidal environments. Willemite ore bodies are structurally controlled along regional NE-trending structures which are interpreted as being active during the Neoproterozoic Brasiliano orogeny. The hydrothermal alteration is characterized by an early stage of Fe-dolomite, which replaced the host dolomitic rocks, followed by precipitation of minor sphalerite and then hematite and willemite. Elements commonly enriched in the zinc ore include As, Ba, Be, Bi, Cd, Co, Fe, Ge, In, Mo, Ni, Sb, Se, U, V and W. Mineralogical, fluid inclusion and isotopic data indicates that mixing of S-poor metalliferous saline fluids with meteoric water favored the formation of willemite ore. Carbonaceous phyllites from the underlying thick siliciclastic sequence show evidence of early enrichment in zinc (and ore-related metals) and remobilization, respectively, prior to and during the Brasiliano orogenic event. This unit is interpreted as a possible source of ore-related elements. It is proposed that during the Brasiliano orogeny, hot (T > 170 degrees C) saline fluids (>15 wt % eq. NaCl) leached metals from siliciclastic source rocks and precipitated willemite ore in the overlying dolomitic sequence along structures that favored mixing with oxidizing meteoric water

    A Model to Enable the Reuse of Metadata-Based Frameworks in Adaptive Object Model Architectures

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    The Adaptive Object Model (AOM) is an architectural style in which domain entity types are represented as instances that can be changed at runtime. It can be used to achieve higher flexibility in domain classes. Due to AOM entities having a distinct structure, they are not compatible with most popular frameworks, especially those that use reflection and code annotations. To solve such limitations, this study aims to propose a model that enables the reuse of frameworks designed for classic object-oriented domain models in an AOM application. The proposed model uses dynamically-generated adapters for AOM entities that encapsulate them in a class with the format expected by the frameworks. A reference implementation was developed in the Esfinge AOM RoleMapper framework to evaluate the viability of the proposed model. Initially, to evaluate the solution feasibility, a case study was carried out using the Hibernate framework. Further, an experiment was conducted to assess how the participants perceived the framework functionality reuse through the proposed model. The feasibility study revealed that the solution could be applied in a complex setting for the chosen object-relational mapping frame. It raised some difficulties that can be addressed in future studies. In the experiment, the development time did not present a significant difference compared to the competing approach. Despite the considerable learning curve, most participants considered that the proposed approach has more advantages than the alternative. Based on the evaluations, we can conclude that the proposed model can be successfully employed to use AOM entities with frameworks that were not designed for AOM applications. The possibility of reusing existing frameworks can reduce the effort required to adopt an AOM architecture and, consequently, be a facilitator in implementing more flexible and adaptive approaches
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