257 research outputs found
Fitting isochrones to open cluster photometric data III. Estimating metallicities from UBV photometry
The metallicity is a critical parameter that affects the correct
determination fundamental characteristics stellar cluster and has important
implications in Galactic and Stellar evolution research. Fewer than 10 % of the
2174 currently catalog open clusters have their metallicity determined in the
literature. In this work we present a method for estimating the metallicity of
open clusters via non-subjective isochrone fitting using the cross-entropy
global optimization algorithm applied to UBV photometric data. The free
parameters distance, reddening, age, and metallicity simultaneously determined
by the fitting method. The fitting procedure uses weights for the observational
data based on the estimation of membership likelihood for each star, which
considers the observational magnitude limit, the density profile of stars as a
function of radius from the center of the cluster, and the density of stars in
multi-dimensional magnitude space. We present results of [Fe/H] for nine
well-studied open clusters based on 15 distinct UBV data sets. The [Fe/H]
values obtained in the ten cases for which spectroscopic determinations were
available in the literature agree, indicating that our method provides a good
alternative to determining [Fe/H] by using an objective isochrone fitting. Our
results show that the typical precision is about 0.1 dex
Recommended from our members
Giant cutaneous horn on the lower lip
Cutaneous horn is a conical hyperkeratotic projection of the skin composed of compact keratin. A wide range of pathologic conditions may be found at its base, including a significant proportion of malignant tumors. A notable, giant cutaneous horn uncovering a keratoacanthoma/well-differentiated squamous cell carcinoma is presented, highlighting the importance of histopathological examination to rule out malignancy because clinical features cannot assure a correct diagnosis
Estudo palinostratigráfico do setor Malhadinha, região NE Alvares, concelho de Mértola, Faixa Piritosa Ibérica
Cartografia geológica realizada pelo Laboratório Nacional de Energia e Geologia (LNEG) acompanhada por estudos palinostratigráficos na região de Malhadinha, NE de Alvares, localizada no setor WNW da Faixa Piritosa Ibérica (FPI), concelho de Mértola, possibilitaram o conhecimento de detalhe da estratigrafia local. Apresentam-se as idades obtidas por palinologia para as formações Barranco do Homem e Filito-Quartzítica, ambas de idade do Famenniano superior, e Freixial, de idade do Viseano superior, correlacionando-se os dados obtidos com a geologia regional da FPI. Os dados obtidos confirmam o predomínio de estruturas alóctones no setor norte da Faixa Piritosa, entre Alvares e a fronteira espanhola.Geological mapping performed by the National Laboratory of Energy and Geology (LNEG) and palynostratigraphic studies carried out in Malhadinha region, NE of Alvares village, located in the northern sector of the Iberian Pyrite Belt (IPB), WNW of Mértola, allowed to obtain a detailed knowledge of the local stratigraphy. Age data obtained by palynology to the Barranco do Homem (upper Famennian age), Phyllite-Quartzite (upper Famennian age), and Freixial (Visean age), formations are presented and discussed according to the IPB regional geological setting. The age data confirm the predominance of alloctonous tectonic structures in the studied region, in line with previous structural interpretations for the North Sector of the Portuguese part of the Iberian Pyrite Belt.(undefined
Procedures for quality control of genotypes used in genomic evaluations of hereford and braford cattle in Brazil.
Alterações recentes nas razões isotópicas de Pb em sedimentos do Canhão Submarino de Cascais, Portugal
Temporal variations in lead concentrations and stable lead isotopic ratios in two sediment cores from the Cascais Canyon shows
changes in sources of Pb during the last two centuries. The increase of total Pb contents wIth the evolution of Pb ratio recorded in
both cores reveals the Increase of Pb from industrial sources. Nevertheless, this increase is lower in deeper core location (252-32)
due to dilution and mixing with uncontaminated marine materials. An isotopic shift towards lower Pb/Pb in the shallower core
(252-35) during the 1970s may reflect the increasing number of vehicles in the Lisboa area during that time
A Multi-Analytical study of Rock Paintings from Leandro 5 Megalithic Barrow, North-Weastern Portugal
The colourant composition of a northern Portugal megalithic barrow decorated with ‘solar’ motifs was studied using a multi-analytical approach, allowing the characterisa- tion of the painting techniques, pigments and binders. The red pigment was prepared with iron oxide minerals, using vegetal oils as organic additives, while the black pigment was char- coal without any organic additives or binders. The solar motif was first drawn with charcoal and subsequently painted with a red pigment.The work was supported by UID/QUI/50006/2019 with
funding from FCT/MCTES through national funds. César
Oliveira acknowledges Instituto de Ciências e Tecnologias
Agrárias e Agro-Alimentares, Porto (ICETA), for his contract
under project NORTE-01-0145-FEDER-000011. This work
was also developed under the project ‘Funerary and ceremonial practices between the Neolithic and the Bronze Age approached by archaeometry’ (ARQUEOM/Project-Sept2014)
Otimização de protocolos para extração de proteínas em raízes de feijão-de-corda (Vigna unguiculata) infectadas com o nematóide Meloidogyne incógnita.
bitstream/CENARGEN/29751/1/bp210.pd
PROPOSITION AND EVALUATION OF NATIVE VEGETATION RECOVERING INDEX (NVRI) OF RURAL PROPERTY
- …