11,963 research outputs found

    Abundance patterns in early-type galaxies: is there a 'knee' in the [Fe/H] vs. [alpha/Fe] relation?

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    Early-type galaxies (ETGs) are known to be enhanced in alpha elements, in accordance with their old ages and short formation timescales. In this contribution we aim to resolve the enrichment histories of ETGs. This means we study the abundance of Fe ([Fe/H]) and the alpha-element groups ([alpha/Fe]) separately for stars older than 9.5 Gyr ([Fe/H]o, [alpha/Fe]o) and for stars between 1.5 and 9.5 Gyr ([Fe/H]i, [alpha/Fe]i). Through extensive simulation we show that we can indeed recover the enrichment history per galaxy. We then analyze a spectroscopic sample of 2286 early-type galaxies from the SDSS selected to be ETGs. We separate out those galaxies for which the abundance of iron in stars grows throughout the lifetime of the galaxy, i.e. in which [Fe/H]o < [Fe/H]i. We confirm earlier work where the [Fe/H] and [alpha/Fe] parameters are correlated with the mass and velocity dispersion of ETGs. We emphasize that the strongest relation is between [alpha/Fe] and age. This relation falls into two regimes, one with a steep slope for old galaxies and one with a shallow slope for younger ETGs. The vast majority of ETGs in our sample do not show the 'knee' in the plot of [Fe/H] vs. [alpha/Fe] commonly observed in local group galaxies. This implies that for the vast majority of ETGs, the stars younger than 9.5 Gyrs are likely to have been accreted or formed from accreted gas. The properties of the intermediate-age stars in accretion-dominated ETGs indicate that mass growth through late (minor) mergers in ETGs is dominated by galaxies with low [Fe/H] and low [alpha/Fe]. The method of reconstructing the stellar enrichment histories of ETGs introduced in this paper promises to constrain the star formation and mass assembly histories of large samples of galaxies in a unique way.Comment: 22 pages, 25 figures, accepted for publication by A&

    HIV-1 mother-to-child transmission in Brazil (1994\u20132016): a time series modeling

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    HIV-1 mother-to-child transmission (HIV-1 MTCT), is an important cause of children mortality worldwide. Brazil has been traditionally praised by its HIV/Aids program, which provides free-of-charge care for people living with HIV-1. Using public epidemiology and demographic databases, we aimed at modeling HIV-1 MTCT prevalence in Brazil through the years (1994\u20132016) and elaborate a statistical model for forecasting, contributing to HIV-1 epidemiologic surveillance and healthcare decision-making. We downloaded sets of live births and mothers\u2019 data alongside HIV-1 cases notification in children one year old or less. Through time series modeling, we estimated prevalence along the years in Brazil, and observed a remarkable decrease of HIV-1 MTCT between 1994 (10 cases per 100,000 live births) and 2016 (five cases per 100,000 live births), a reduction of 50%. Using our model, we elaborated a prognosis for each Brazilian state to help HIV-1 surveillance decision making, indicating which states are in theory in risk of experiencing a rise in HIV-1 MTCT prevalence. Ten states had good (37%), nine had mild (33%), and eight had poor prognostics (30%). Stratifying the prognostics by Brazilian region, we observed that the Northeast region had more states with poor prognosis, followed by North and Midwest, Southeast and South with one state of poor prognosis each. Brazil undoubtedly advanced in the fight against HIV-1 MTCT in the past two decades. We hope our model will help indicating where HIV-1 MTCT prevalence may rise in the future and support government decision makers regarding HIV-1 surveillance and prevention

    Influence of açai fruits (Euterpe oleracea Mart.) conservation on the acceptance of açai drink.

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    The açai drink is consumed habitually by populations of northern Brazil, but one of the major bottlenecks in the production of this drink is the seasonality of fruit production. Hence the needs to study the influence of cold storage on the transport of fruits from distant locations, such as the archipelago of Bailique (AP, Brazil) until the consumer centers. In this context, fruits collected and packaged under refrigeration and room temperatures were transported by boat for twelve hours and were subsequently processed in a mixer. Sensory analysis was performed in two consecutive days and the samples were stored under refrigeration. This analysis was performed by affective method with global acceptance (n=54) and the samples presented in a balanced way. It was used a hedonic scale with 9 points, ranging from like extremely (9) to dislike extremely (1). The results show that cold storage of the fruits affected significantly (p=0.002467) the acceptance of beverages in both two days of sensory evaluation. On the first day, the drink originated from fruits transported at cold storage received note 8 (liked a lot), while the drink from fruits at room temperature reached grade 7 (like moderately). On the second day of evaluation, the drink from refrigerated fruits received note 7 (like moderately) and drink from fruits stored at room temperature obtained note 5 (indifferent). Considering the type of preservation of fruits, no sensory difference was detected between the drinks from refrigerated fruits served on the two consecutive days, as well as no significant difference in drink of fruits transported at room temperature in this same period. It was concluded that açai fruits collected in regions distant from the consumer center, but kept under refrigeration, produce a drink with a considerable acceptance level, and they could be an alternative for supply of raw material during the off season.Resumo P1.5.010

    Espacialização de indicadores socioeconômicos como subsídio ao macrozoneamento ecológico-econômico do Estado do Maranhão.

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    Macrozoneamentos ecológico-econômicos foram instituídos pelo governo federal e têm como finalidade identificar potencialidades e limitações de recursos naturais e da sociedade com base em um diagnóstico socioambiental e com o propósito de apoiar a formulação e execução de políticas de desenvolvimento regional . Indicadores socioeconômicos são instrumentos importantes em todas as fases do processo de formulação, implementação, monitoramento e avaliação das políticas públicas, e são elementos indispensáveis para a elaboração de macrozoneamentos ecológico-econômicos . O objetivo deste trabalho foi espacializar indicadores socioeconômicos que serão utilizados como subsídio para a elaboração do Macrozoneamento Ecológico-Econômico do Estado do Maranhão. Foram adotados, como unidade de referência territorial, os 217 municípios que compõem o estado e, como fonte de dados, a Produção Agrícola Municipal (PAM) do IBGE e o Censo Demográfico do IBGE. Foram selecionados os principais indicadores socioeconômicos, como saneamento básico, energia, água potável, saúde, educação, entre outros. O procedimento metodológico utilizado foi: definição e levantamento dos indicadores; criação e formatação das tabelas com auxílio do programa Excel; e, por fim, a utilização do software ArcGIS (ESRI), que, por meio das planilhas criadas, dos geocódigos municipais e dos shapefile disponibilizados pelo IBGE, possibilitou espacializar os dados e, assim, gerar os mapas temáticos. A espacialização dos indicadores pode contribuir para a formulação de políticas públicas em diferentes níveis de governo e, assim, para que sejam tomadas decisões mais adequadas
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