7,258 research outputs found
Metallicity of low-mass stars in Orion
Determining the metal content of low-mass members of young associations
provides a tool that addresses different issues, such as triggered star
formation or the link between the metal-rich nature of planet-host stars and
the early phases of planet formation. The Orion complex is a well known example
of possible triggered star formation and is known to host a rich variety of
proto-planetary disks around its low-mass stars. Available metallicity
measurements yield discrepant results. We analyzed FLAMES/UVES and Giraffe
spectra of low-mass members of three groups/clusters belonging to the Orion
association. Our goal is the homogeneous determination of the metallicity of
the sample stars, which allows us to look for [Fe/H] differences between the
three regions and for the possible presence of metal-rich stars. Nine members
of the ONC and one star each in the Ori cluster and OB1b subgroup
were analyzed. After the veiling determination, we retrieved the metallicity by
means of equivalent widths and/or spectral synthesis using MOOG. We obtain an
average metallicity for the ONC [Fe/H]=-0.01\pm 0.04. No metal-rich stars were
detected and the dispersion within our sample is consistent with measurement
uncertainties. The metallicity of the Ori member is also solar, while
the OB1b star has an [Fe/H] significantly below the ONC average. If confirmed
by additional [Fe/H] determinations in the OB1b subgroup, this result would
support the triggered star formation and the self-enrichment scenario for the
Orion complex.Comment: 13 pages, accepted for publication in A&
Corrupción, inseguridad pública y bienestar subjetivo en México
No obstante sus problemas sociales y públicos, México se mantiene bien posicionado en los índices mundiales de felicidad, lo que despierta dudas acerca de la conformación del bienestar subjetivo de su población. Con información de distintas encuestas nacionales, este artículo presenta un análisis descriptivo y otro econométrico para conocer cómo distintos satisfactores y afectos del ámbito personal y la percepción de factores contextuales y socioculturales como la corrupción e inseguridad pública, se relacionan con la percepción de bienestar. Se encontró que, en la construcción del bienestar subjetivo, se da más peso a factores del ámbito personal y menos a los de contexto a mayor presencia de los problemas sociales y públicos, haciendo posible que la percepción de una mayor corrupción y la de un mayor bienestar pueden coexistir. La evidencia sugiere que la población en México se ha desarrollado tolerancia a este problema
Determinação do pico da lactemia de cavalos pantaneiros após exercício de alta intensidade no Pantanal.
Este trabalho teve como objetivo avaliar o pico da lactatemia de cavalos Pantaneiros. Para tanto, foi realizada uma prova com cinco animais, submetidos a exercício de alta intensidade em condições de alta temperatura no Pantanal, e colhidas amostras para dosagem de lactato durante o período de recuperação após o esforço físico. Os resultados encontrados sugerem a interferência de fatores como condicionamento físico e idade no tempo de exportação do lactato da musculatura para a corrente sanguínea. A determinação do pico do lactato sanguíneo após exercícios de máximo esforço pode ser uma importante ferramenta nos programas de seleção e melhoramento de cavalos Pantaneiros, baseados em critérios funcionais, assim como nos programas de treinamento e adestramento da raça
Utilização do método do disco medidor na avaliação de massa forrageira em pastagens nativas do Pantanal.
Este trabalho teve como objetivo avaliar o método do disco medidor e outros métodos indiretos para estimar a massa de matéria seca de dois tipos de pastagens naturais, uma com predominância de capim-carona (Elyonurus muticus) e outra com predominância de capim-vermelho (Andropogon hypogynus), na sub-região da Nhecolândia, Pantanal. Em julho e agosto de 2007, 20 quadrados de 1m2 foram alocados casualmente em quatro pastagens com predominância de capim-carona e quatro pastagens com predominância de capim-vermelho. Em cada quadrado amostral foram feitas as seguintes avaliações: altura média do relvado (AP); altura comprimida com auxilio do disco medidor (AC) e estimativa da porcentagem da cobertura de plantas (CP). Em seguida o material foi cortado rente ao solo para estimativa de matéria seca. Os dados foram submetidos à análise de regressão da produção de matéria seca (g/m2) em função da AP, AC, CP e do índice AC x CP. As melhores estimativas foram obtidas para as pastagens com dominância de capim-carona, principalmente através dos modelos que utilizam altura comprimida e/ou sua combinação com percentual de cobertura de plantas
A Possible Stellar Metallic Enhancement in Post-T Tauri Stars by a Planetesimal Bombardment
The photospheres of stars hosting planets have larger metallicity than stars
lacking planets. In the present work we study the possibility of an earlier
metal enrichment of the photospheres by means of impacting planetesimals during
the first 20-30Myr. Here we explore this contamination process by simulating
the interactions of an inward migrating planet with a disc of planetesimal
interior to its orbit. The results show the percentage of planetesimals that
fall on the star. We identified the dependence of the planet's eccentricity
() and time scale of migration () on the rate of infalling
planetesimals. For very fast migrations (yr and yr) there
is no capture in mean motion resonances, independently of the value of .
Then, due to the planet's migration the planetesimals suffer close approaches
with the planet and more than 80% of them are ejected from the system. For slow
migrations (yr and yr) the percentage of collisions with
the planet decrease with the increase of the planet's eccentricity. For
and most of the planetesimals were captured in the 2:1 resonance and
more than 65% of them collided with the star. Whereas migration of a Jupiter
mass planet to very short pericentric distances requires unrealistic high disc
masses, these requirements are much smaller for smaller migrating planets. Our
simulations for a slowly migrating 0.1 planet, even demanding
a possible primitive disc three times more massive than a primitive solar
nebula, produces maximum [Fe/H] enrichments of the order of 0.18 dex. These
calculations open possibilities to explain hot Jupiters exoplanets
metallicities.Comment: Accepted for publication by Monthly Notices of the Royal Astronomical
Societ
Emerging and recurring diseases in cetaceans worldwide and the role of environmental stressors. Scientific Committee Document SC/60/DW5, International Whaling Commission, June 2008, Santiago, Chile
Emerging and recurring infectious diseases known or suspected to have the potential to significantly impact cetacean populations, and possible synergistic effects of environmental factors are reviewed. Cetacean morbilliviruses and papillomaviruses and brucellosis may affect population densities through high mortality rates or interference with reproduction. Evidence is available for the role of environmental factors in the emergence/recurrence and severity of at least six infectious conditions i.e. lobomycosis, toxoplasmosis, tattoo skin disease, generalized bacterial infections, miscellaneous skin diseases and morbillivirus epizootics. Other micro-parasites of potential importance include rhabdo-, herpes- and parainfluenza-viruses as well as Helicobacter spp., Streptococcus spp., Salmonella spp. and Mycobacterium marinum. The population impact and aetiology of newly emerging skin diseases in South America are unknown and represent a cause of concern
Population inversion of a NAHS mixture adsorbed into a cylindrical pore
A cylindrical nanopore immersed in a non-additive hard sphere binary fluid is
studied by means of integral equation theories and Monte Carlo simulations. It
is found that at low and intermediate values of the bulk total number density
the more concentrated bulk species is preferentially absorbed by the pore, as
expected. However, further increments of the bulk number density lead to an
abrupt population inversion in the confined fluid and an entropy driven
prewetting transition at the outside wall of the pore. These phenomena are a
function of the pore size, the non-additivity parameter, the bulk number
density, and particles relative number fraction. We discuss our results in
relation to the phase separation in the bulk.Comment: 7 pages, 8 Figure
Genetic structure and pod morphology of Inga edulis cultivated vs. wild populations from the Peruvian Amazon
Research Highlights: This study assesses the genetic diversity and structure of the ice-cream-bean (Inga edulis Mart.) (Fabaceae), in wild and cultivated populations from the Peruvian Amazon. This research also highlights the importance of protecting the biodiversity of the forest in the Peruvian Amazon, to preserve the genetic resources of species and allow further genetic improvement. Background and Objectives: Ice-cream-bean is one of the most commonly used species in the Amazon region for its fruits and for shading protection of other species (e.g.: cocoa and coffee plantations). Comprehensive studies about the impact of domestication on this species’ genetic diversity are needed, to find the best conservation and improvement strategies. Materials and Methods: In the current study, the genetic structure and diversity were assessed by genotyping 259 trees, sampled in five wild and 22 cultivated I. edulis populations in the Peruvian Amazon, with microsatellite markers. Pod length was measured in wild and cultivated trees. Results: The average pod length in cultivated trees was significantly higher than that in wild trees. The expected genetic diversity and the average number of alleles was higher in the wild compared to the cultivated populations, thus, a loss of genetic diversity was confirmed in the cultivated populations. The cultivated trees in the Loreto region had the highest pod length and lowest allelic richness, nevertheless the wild populations’ genetic structure was not clearly differentiated (significantly different) from that of the cultivated populations. Conclusions: A loss of genetic diversity was confirmed in the cultivated populations. The species could have been simultaneously domesticated in multiple locations, usually from local origin. The original I. edulis Amazonian germplasm should be maintained. Cultivated populations’ new germplasm influx from wild populations should be undertaken to increase genetic diversity.info:eu-repo/semantics/publishedVersio
Cost-effectiveness of multicomponent interventions in type 2 diabetes mellitus in a cluster randomised controlled trial: the INDICA study
Objective: To analyse the cost-effectiveness of multicomponent interventions designed to improve outcomes in type 2 diabetes mellitus (T2DM) in primary care in the Canary Islands, Spain, within the INDICA randomised clinical trial, from the public health system perspective. Design: An economic evaluation was conducted for the within-trial period (2 years) comparing the four arms of the INDICA study. Setting: Primary care in the Canary Islands, Spain. Participants: 2334 patients with T2DM without complications were included. Interventions: Interventions for patients (PTI), for primary care professionals (PFI), for both (combined intervention arm for patients and professionals, CBI) and usual care (UC) as a control group. Outcomes: The main outcome was the incremental cost per quality-adjusted life-years (QALY). Only the intervention and the healthcare costs were included. Analysis: Multilevel models were used to estimate results, and to measure the size and significance of incremental changes. Missed values were treated by means of multiple imputations procedure. Results: There were no differences between arms in terms of costs (p=0.093), while some differences were observed in terms of QALYs after 2 years of follow-up (p=0.028). PFI and CBI arms were dominated by the other two arms, PTI and UC. The differences between the PTI and the UC arms were very small in terms of QALYs, but significant in terms of healthcare costs (p=0.045). The total cost of the PTI arm (€2571, 95% CI €2317 to €2826) was lower than the cost in the UC arm (€2750, 95% CI €2506 to €2995), but this difference did not reach statistical significance. Base case estimates of the incremental cost per QALY indicate that the PTI strategy was the cost-effective option. Conclusions: The INDICA intervention designed for patients with T2DM and families is likely to be cost-effective from the public healthcare perspective. A cost-effectiveness model should explore this in the long term.This study received financial support from the Spanish Ministry of Economy, Industry and Competitiveness (Instituto de Salud Carlos III), grants: ADE10/00032 and PI16/00769, jointly funded by the European Regional Development Fund (FEDER) ‘A way to make Europe’. The sponsor did not play any role in study design, collection, analysis and interpretation of data, drawing up of the report or the decision to submit the article for publication.S
Strong relationships between soil and vegetation in reference ecosystems of a riparian atlantic rainforest in the upper Doce River watershed, southeastern Brazil
Habitat loss and fragmentation have been impacting ecosystem services essential for human survival. The Brazilian Atlantic rainforest, a biodiversity hotspot, has suffered from historical deforestation and, more recently, from an environmental disaster caused by the Fundão dam collapse that released ore tailings drastically affecting a large territory in the Doce River watershed. This work aims to assess the relationships between soil properties and vegetation in a reference ecosystem to provide guidelines for restoration projects in areas affected by the dam collapse. We conducted phytosociological (vegetation characteristic) and soil quality studies in three distinct natural sites and studied different vegetation strata to better understand plant species composition in reference sites along the impacted Doce River and their potential role in community structuring and functioning. We recorded 140 species, 78 in the tree stratum, and 90 in the sapling stratum. Furthermore, our results highlight the influence of soil on floristic composition in the Atlantic rainforest. Smallscale edaphic variation influenced species composition in both sapling and tree strata. We also identified species of the same genus with strong association with the extremes of the edaphic gradient. Therefore, we highlight that studies in various regions along the Doce River watershed are of utmost importance to evaluate the association between species and soils. The particularities of the species are crucial to the effectiveness of restoration processes since this plant-soil correlation should not be extrapolated even within the same genus. This knowledge is of strategic relevance to provide scientificbased guidance for restoring these environments, aiming at the recovery of biodiversity and ecosystem services.Fil: Ramos, Letícia. Universidade Federal de Minas Gerais; BrasilFil: Negreiros, Daniel. Universidade Federal de Minas Gerais; BrasilFil: Ferreira, Bárbara S. Silva. Universidade Federal de Minas Gerais; BrasilFil: Figueiredo, João Carlos Gomes. Universidade Estadual de Montes Claros; BrasilFil: Paiva, Dario C.. Florida International University; Estados UnidosFil: Oki, Yumi. Universidade Federal de Minas Gerais; BrasilFil: De Souza Justino, Wénita. Universidade Federal de Minas Gerais; BrasilFil: Dos Santos, Rubens Manoel. Universidade Federal de Lavras; BrasilFil: Aguilar, Ramiro. Universidade Federal de Minas Gerais; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Nunes, Yule Roberta Ferreira. Universidade Estadual de Montes Claros; BrasilFil: Fernandes, G Wilson. Universidade Federal de Minas Gerais; Brasi
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