9,454 research outputs found
Self-consistent physical parameters for MC clusters from CMD modelling: application to SMC clusters observed with the SOAR telescope
The Magellanic Clouds (MCs) present a rich system of stellar clusters that
can be used to probe the dynamical and chemical evolution of these neighboring
and interacting irregular galaxies. In particular, these stellar clusters (SCs)
present combinations of age and metallicity that are not found for this class
of objects in the Milky Way, being therefore very useful templates to test and
to calibrate integrated light simple stellar population (SSP) models applied to
unresolved distance galaxies. On its turn, the age and metallicity for a
cluster can be determined spatially resolving its stars, by means of analysis
of its colour-magnitude diagrams (CMDs). In this work we present our method to
determine self-consistent physical parameters (age, metallicity, distance
modulus and reddening) for a stellar cluster, from CMDs modelling of relatively
unstudied SCs in the Small Magellanic Cloud (SMC) imaged in the BVI filters
with the 4.1 m SOAR telescope. Our preliminary results confirm our expectations
that come from a previous integrated spectra and colour analysis: at least one
of them (Lindsay 2) is an intermediate-age stellar cluster with ~ 2.6 Gyr and
[Fe/H] ~ -1.3, being therefore a new interesting witness regarding the
reactivation of the star formation in the MCs in the last 4 Gyr.Comment: 4 pages, 2 figures. To be published in the proceedings of IAUS256:
The Magellanic System: Stars, Gas, and Galaxie
Primeiro relato de Braga patagonica Schödte & Meinert, 1884 (Crustacea: Isopoda) parasitando peixes cultivados no Brasil.
Resumo simples
In-Situ Component-Based TPA for Time-Variant Dynamic Systems: A State-Space Formulation
In this chapter, a methodology to calculate equivalent forces by taking into account the possible time-varying dynamic behavior of the components under analysis is presented. This methodology is based on the use of the state-space realization of the in-situ component-based TPA method. To take into account possible time-varying dynamic behavior of the systems under study, a local linear parameter varying (LPV) model identification approach is used. This approach enables the computation of state-space models representative of the components at each time instant by interpolating a given set of linear time-invariant (LTI) state-space models representative of the dynamics of the components under study for fixed operating conditions. By exploiting a numerical example, it is found that when dealing with structures presenting time-varying behavior, accurate equivalent forces can be computed in time domain by using the approaches presented in this chapter. Furthermore, it is clearly demonstrated that ignoring the time dependency of the dynamic behavior of mechanical systems can lead to an important deterioration of the results
New hosts and distribution records of Braga patagonica, a parasite cymothoidae of fishes from the Amazon.
Specimens of Braga patagonica Schiödte & Meinert, 1884 (Isopoda: Cymothoidae) from freshwater fishes deposited in Ichthyological Collection of Amazon National Research Institute (INPA), in central Amazon and from fishes from eastern Amazon (Brazil) were investigated. Prevalence, infection intensity and body measures of B. patagonica for different populations of this cymothoid in wild fishes species from Amazon were carried out. Four species of Serrasalmidae, one Characidae, one Cichlidae, one Cynodontidae, one Curimatidae, one Acestrorhynchidae and one Sciaenidae were recorded as new hosts for B. patagonica in the Amazon. This study indicates a low intensity and low parasitic specificity of B. patagonica, and also recorded the first parasitism by this ectoparasite in farmed Colossoma macropomum, describing its highly pathogenic effect
Properties of Solutions in 2+1 Dimensions
We solve the Einstein equations for the 2+1 dimensions with and without
scalar fields. We calculate the entropy, Hawking temperature and the emission
probabilities for these cases. We also compute the Newman-Penrose coefficients
for different solutions and compare them.Comment: 16 pages, 1 figures, PlainTeX, Dedicated to Prof. Yavuz Nutku on his
60th birthday. References adde
Relação peso-comprimento e fator de condição relativo (Kn) do pirarucu Arapaima gigas Schinz, 1822 (Arapaimidae) em cultivo semi-intensivo no estado do Amazonas, Brasil.
O pirarucu Arapaima gigas (Osteoglossiformes, Arapaimidae), peixe da bacia amazônica, apresenta alta taxa de crescimento e tolerância a alta densidade de estocagem, tem rusticidade ao manuseio e aceita alimentação artificial quando treinado no início da vida, características relevantes para o cultivo de peixe. Neste estudo, a relação peso-comprimento (W=a·Lb) e o fator de condição relativo (Kn) foram estimados para alevinos, juvenis e jovens de pirarucus cultivados em piscicultura semi-intensiva no município de Manacapuru, estado do Amazonas, na Amazônia central, Brasil. Alevinos foram previamente treinados para aceitar ração comercial durante no início da vida e depois foram alimentados com ração para peixes contendo 45% de proteína bruta. A equação relação peso-comprimento mostrou crescimento do tipo isométrico, com valor da constante de regressão (b) igual 3,068. O Kn variou de 0.811 a 1.170 (média de 1.007 ± 0.059) e esses valores elevados indicaram boas condições corporais dos peixes nas condições cultivadas
Sistemas de produção de pequenos produtores de mandioca no município de Bragança, Pará.
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