1,911 research outputs found

    A grid of Synthetic Spectra for Hot DA White Dwarfs and Its Application in Stellar Population Synthesis

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    In this work we present a grid of LTE and non-LTE synthetic spectra of hot DA white dwarfs (WDs). In addition to its usefulness for the determination of fundamental stellar parameters of isolated WDs and in binaries, this grid will be of interest for the construction of theoretical libraries for stellar studies from integrated light. The spectral grid covers both a wide temperature and gravity range, with 17,000 K <= T_eff <= 100,000 K and 7.0 <= log(g) <= 9.5. The stellar models are built for pure hydrogen and the spectra cover a wavelength range from 900 A to 2.5 microns. Additionally, we derive synthetic HST/ACS, HST/WFC3, Bessel UBVRI and SDSS magnitudes. The grid was also used to model integrated spectral energy distributions of simple stellar populations and our modeling suggests that DAs might be detectable in ultraviolet bands for populations older than ~8 Gyr.Comment: to be published in The Astrophysical Journal Supplement Serie

    Educação rodoviária: estudo de caso

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    A sinistralidade rodoviária transformou-se numa doença social, das principais causas de morte, internamentos, tratamentos prolongados e incapacidades permanentes. Com os programas de segurança rodoviária a sinistralidade rodoviária tem diminuído. Em que medida estes programas incluem a educação rodoviária? Na escolaridade obrigatória é (ou não) abordada a educação rodoviária? O que pensam os professores sobre esta temática nos currículos escolares? Usa-se o método comparativo na análise das orientações e programas internacionais sobre segurança rodoviária. Analisa-se em estudo de caso as representações de professores sobre a educação rodoviária nas escolas. A educação rodoviária constitui uma necessidade básica de aprendizagem para todos

    Full spectral fitting of Milky Way and M31 globular clusters: ages and metallicities

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    Context: The formation and evolution of disk galaxies are long standing questions in Astronomy. Understanding the properties of globular cluster systems can lead to important insights on the evolution of its host galaxy. Aims: We aim to obtain the stellar population parameters - age and metallicity - of a sample of M31 and Galactic globular clusters. Studying their globular cluster systems is an important step towards understanding their formation and evolution in a complete way. Methods: Our analysis employs a modern pixel-to-pixel spectral fitting technique to fit observed integrated spectra to updated stellar population models. By comparing observations to models we obtain the ages and metallicities of their stellar populations. We apply this technique to a sample of 38 globular clusters in M31 and to 41 Galactic globular clusters, used as a control sample. Results: Our sample of M31 globular clusters spans ages from 150 Myr to the age of the Universe. Metallicities [Fe/H] range from -2.2 dex to the solar value. The age-metallicity relation obtained can be described as having two components: an old population with a flat age-[Fe/H] relation, possibly associated with the halo and/or bulge, and a second one with a roughly linear relation between age and metallicity, higher metallicities corresponding to younger ages, possibly associated with the M31 disk. While we recover the very well known Galactic GC metallicity bimodality, our own analysis of M31's metallicity distribution function (MDF) suggests that both GC systems cover basically the same [Fe/H] range yet M31's MDF is not clearly bimodal. These results suggest that both galaxies experienced different star formation and accretion histories.Comment: A&A, in pres

    Structural equation modelling for predicting the relative contribution of each component in the metabolic syndrome status change

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    Understanding the factor weighting in the development of metabolic syndrome (MetS) may help to predict the progression for cardiovascular and metabolic diseases. Thus, the aim of this study was to develop a confirmatory model to describe and explain the direct and indirect effect of each component in MetS status change. A total of 3581 individuals diagnosed with MetS, aged 18–102 years, were selected between January 2019 and December 2020 from a community-representative sample of Portuguese adults in a north-eastern Portuguese region to test the model’s goodness of fit. A structural equation modelling (SEM) approach and a two-way ANOVA (age × body composition) were performed to compare the relative contribution of each MetS component using joint interim statement (JIS). Waist circumference (β = 0.189–0.373, p < 0.001), fasting glucose (β = 0.168–0.199, p < 0.001) and systolic blood pressure (β = 0.140–0.162, p < 0.001) had the highest direct effect on the change in MetS status in the overall population and concerning both sexes. Moreover, diastolic blood pressure (DBP), triglycerides (TG) and high-density lipoprotein cholesterol (HDL-c) had a low or non-significant effect. Additionally, an indirect effect was reported for age and body composition involving the change in MetS status. The findings may suggest that other components with higher specificity and sensitivity should be considered to empirically validate the harmonised definition of MetS. Current research provides the first multivariate model for predicting the relative contribution of each component in the MetS status change, specifically in Portuguese adults.This article is a result of the project “GreenHealth-Digital strategies in biological assets to improve well-being and promote green health” (Norte-01-0145-FEDER-000042), supported by North Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). The authors also express acknowledgement all medical staff, patients and human resources of the two primary health care centers.info:eu-repo/semantics/publishedVersio

    A Leishmania-specific hypothetical protein expressed in both promastigote and amastigote stages of Leishmania infantum employed for the serodiagnosis of, and as a vaccine candidate against, visceral leishmaniasis

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    Background: LiHyV is an antigenic hypothetical protein present in both promastigote and amastigote stages of Leishmania infantum, which was recently identified by an immunoproteomic approach. A recombinant version of this protein (rLiHyV) was evaluated as a diagnostic marker for canine VL (CVL). In addition, the prophylactic efficacy of the rLiHyV protein, and two of its CD8+ T cell epitopes, has been analyzed in a murine model of visceral leishmaniasis (VL). Methods: Initially, the rLiHyV protein was evaluated by an ELISA technique for the serodiagnosis of CVL. Secondly, vaccines composed of the recombinant protein and both chemically synthesized peptides, combined with saponin as an adjuvant; were administered subcutaneously into BALB/c mice. The cellular and humoral responses generated by vaccination were evaluated. In addition, the parasite burden and immune response were studied 10 weeks after L. infantum infection. Results: The rLiHyV protein was recognized by antibodies of VL dogs. No cross-reactivity was obtained with sera from dogs vaccinated with a Brazilian commercial vaccine, with sera from animals infected with Trypanosoma cruzi, Babesia canis and Ehrlichia canis, or those from non-infected animals living in an endemic area for leishmaniasis. After challenge with L. infantum, spleen cells of BALB/c mice vaccinated with rLiHyV/saponin stimulated with parasite antigens showed a higher production of IFN-γ, IL-12 and GM-CSF, than the same cells obtained from mice vaccinated with the individual peptides, or mice from control (inoculated with saline or saponin) groups. This Th1-type cellular response observed in rLiHyV/saponin vaccinated mice was accompanied by the induction of parasite-specific IgG2a isotype antibodies. Animals immunized with rLiHyV/saponin showed significant reductions in the parasite burden in the liver, spleen, bone marrow and in the lymph nodes draining the paws relative to control mice. Conclusions: The present study showed for the first time that the L. infantum LiHyV protein could be considered as a vaccine candidate against L. infantum infection, as well as a diagnostic marker for CVL.This work was supported by grants from Instituto Nacional de Ciência e Tecnologia em Nanobiofarmacêutica (INCT-Nanobiofar), FAPEMIG (CBB-APQ-00819-12), and CNPq (APQ-472090/2011-9, RHAE-456287/2012-4, APQ-482976/2012-8, and APQ-488237/2013-0). MACF is a grant recipient of FAPEMIG/CAPES. EAFC and APF are grant recipient of CNPq.Peer Reviewe

    ANALYSIS OF DISCRIMINATORY GAME VARIABLES BETWEEN WINNERS AND LOSERS IN WOMEN’S HANDBALL WORLD CHAMPIONSHIPS FROM 2007 TO 2017

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    The aim of this study was to identify game variables that discriminated winning from losing teams and to understand how these variables contributed to victory by observing goal differences in matches of the women’s handball world championships. The sample comprised 471 WCh’s games played between 2007 and 2017. The games were grouped into three clusters: balanced games – difference of 1-8 goals; unbalanced games – difference of 9-20 goals; and very unbalanced games – difference of > 20 goals. Generally, the performance of winning teams was significantly higher (in most variables), or lower in the case of the number of technical faults (p<.05). In the balanced games, there was a greater contribution of defensive variables (stolen balls, blocked throws, and goalkeeper’s efficiency indicators) in relation to attack variables (attack efficiency and throw efficiency indicators). For victory, the number of technical faults reduce the chances of winning. Games with the unbalanced and very unbalanced goal differences seem to follow the same tendency; however, in the very unbalanced games, there were more assists, yellow cards and 2-min suspensions. We concluded that the decisive variables for victory in the balanced games showed a greater weight, with a special emphasis on stolen balls followed by offensive variables (throw efficiency indicators, attack efficiency, and technical faults). There was an equal tendency for the games with unbalanced and very unbalanced outcomes

    Magnetocaloric effect and evidence of superparamagnetism in GdAl2 nanocrystallites: a magnetic-structural correlation

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    CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMAFINEP - FINANCIADORA DE ESTUDOS E PROJETOSThe correlation between structural and magnetic properties of GdAl2, focusing on the role played by the disorder in magnetic ordering and how it influences the magnetocaloric effect (MCE) are discussed. Micrometric-sized particles, consisting of nanocrystallites embedded in an amorphous matrix, were prepared by a mechanical milling technique and characterized by means of x-ray diffraction, scanning and high-resolution transmission electron microscopy as well as magnetic measurements as a function of an applied external magnetic field and temperature. The results show that the average particle size is just slightly diminished (approximate to 7%) with the milling time (between 3 and 13 h), whereas the average crystallite size undergoes an expressive reduction (approximate to 43%). For long milling times, structural disorders mostly associated with crystallite size singularly affect the magnetic properties, leading to a large tablelike MCE in the temperature range between 30 and 165 K. Below 30 K, nanocrystallites with dimensions below a given critical size cause an enhancement in the magnetic entropy change related to superparamagnetic behavior. In contrast, for low milling times, relative cooling power values are improved. These striking features along with the small magnetic hysteresis observed make the milled GdAl2 a promising material for application in the magnetic refrigeration technology. Finally, a discussion in an attempt to elucidate the origin of the spin-glass states previously reported in the literature for mechanically milled GdAl2 samples for very long times (400 and 1000 h) is presented.The correlation between structural and magnetic properties of GdAl2, focusing on the role played by the disorder in magnetic ordering and how it influences the magnetocaloric effect (MCE) are discussed. Micrometric-sized particles, consisting of nanocrystallites embedded in an amorphous matrix, were prepared by a mechanical milling technique and characterized by means of x-ray diffraction, scanning and high-resolution transmission electron microscopy as well as magnetic measurements as a function of an applied external magnetic field and temperature. The results show that the average particle size is just slightly diminished (approximate to 7%) with the milling time (between 3 and 13 h), whereas the average crystallite size undergoes an expressive reduction (approximate to 43%). For long milling times, structural disorders mostly associated with crystallite size singularly affect the magnetic properties, leading to a large tablelike MCE in the temperature range between 30 and 165 K. Below 30 K, nanocrystallites with dimensions below a given critical size cause an enhancement in the magnetic entropy change related to superparamagnetic behavior. In contrast, for low milling times, relative cooling power values are improved. These striking features along with the small magnetic hysteresis observed make the milled GdAl2 a promising material for application in the magnetic refrigeration technology. Finally, a discussion in an attempt to elucidate the origin of the spin-glass states previously reported in the literature for mechanically milled GdAl2 samples for very long times (400 and 1000 h) is presented.93919CNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMAFINEP - FINANCIADORA DE ESTUDOS E PROJETOSCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO DO MARANHÃO - FAPEMAFINEP - FINANCIADORA DE ESTUDOS E PROJETOSSem informaçãoSem informaçãoSem informaçã

    A Central Limit Theorem for intransitive dice

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    Intransive dice D(1),,D()D^{(1)}, \ldots, D^{(\ell)} are dice such that D(1)D^{(1)} has advantage with respect to D(2)D^{(2)}, dice D(2)D^{(2)} has advantage with respect to D(3)D^{(3)} and so on, up to D()D^{(\ell)}, which has advantage over D(1)D^{(1)}. In this twofold work, we present: first, (deterministic) results on existence of general intransitive dice. Second and mainly, a central limit theorem for the vector of normalized victories of a die against the next one in the list when the faces of a die are i.i.d.\ random variables and all dice are independent, but different dice may have distinct distributions associated to, as well as they may have distinct number of faces. From this central limit theorem we derive a criteria to assure that the asymptotic probability of observing intransitive dice is null, which applies for many cases, including all continuous distributions and many discrete ones.Comment: 37 pages, 3 figure

    Effectiveness of first-line antiretroviral therapy in the IPEC cohort, Rio de Janeiro, Brazil

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    Background: While Brazil has had a long-standing policy of free access to antiretroviral therapy (ART) for all in need, the epidemiological impact of ART on human immunodeficiency virus (HIV) RNA suppression in this middle-income country has not been well evaluated. We estimate first-line ART effectiveness in a large Brazilian cohort and examine the socio-demographic, behavioral, clinical and structural factors associated with virologic suppression. Methods: Virologic suppression on first-line ART at 6, 12, and 24 months from start of ART was defined as having a viral load measurement ≤400 copies/mL without drug class modification and/or discontinuation. Drug class modification and/or discontinuation were defined based on the class of a particular drug. Quasi-Poisson regression was used to quantify the association of factors with virologic suppression. Results: From January 2000 through June 2010, 1311 patients started first-line ART; 987 (75%) patients used NNRTI-based regimens. Virologic suppression was achieved by 77%, 76% and 68% of patients at 6, 12 and 24 months, respectively. Factors associated with virologic suppression at 12 months were: >8 years of formal education (compared to <4 years, risk ratio (RR) 1.13, 95% confidence interval (95% CI) 1.03-1.24), starting ART in 2005-2010 (compared to 2000-2004, RR 1.25 95% CI 1.15-1.35), and clinical trial participation (compared to no participation, RR 1.08 95% CI 1.01-1.16). Also at 12 months, women showed less virologic suppression compared to heterosexual men (RR 0.90 95% CI 0.82-0.99). For the 24-month endpoint, in addition to higher education, starting ART in the later period, and clinical trial participation, older age and an NNRTI-based regimen were also independently associated with virologic suppression. Conclusions: Our results show that in Brazil, a middle-income country with free access to treatment, over three-quarters of patients receiving routine care reached virologic suppression on first-line ART by the end of the first year. Higher education, more recent ART initiation and clinical trial participation were associated with improved outcomes both for the 12-month and the 24-month endpoints, suggesting that further studies are needed to understand what aspects relating to these factors lead to higher virologic suppression
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