Prospects for asteroseismology

The observational basis for asteroseismology is being dramatically strengthened, through more than two years of data from the CoRoT satellite, the flood of data coming from the Kepler mission and, in the slightly longer term, from dedicated ground-based facilities. Our ability to utilize these data depends on further development of techniques for basic data analysis, as well as on an improved understanding of the relation between the observed frequencies and the underlying properties of the stars. Also, stellar modelling must be further developed, to match the increasing diagnostic potential of the data. Here we discuss some aspects of data interpretation and modelling, focussing on the important case of stars with solar-like oscillations.Comment: Proc. HELAS Workshop on 'Synergies between solar and stellar modelling', eds M. Marconi, D. Cardini & M. P. Di Mauro, Astrophys. Space Sci., in the press Revision: correcting abscissa labels on Figs 1 and

ASTEC -- the Aarhus STellar Evolution Code

The Aarhus code is the result of a long development, starting in 1974, and still ongoing. A novel feature is the integration of the computation of adiabatic oscillations for specified models as part of the code. It offers substantial flexibility in terms of microphysics and has been carefully tested for the computation of solar models. However, considerable development is still required in the treatment of nuclear reactions, diffusion and convective mixing.Comment: Astrophys. Space Sci, in the pres

Inter-comparison of the g-, f- and p-modes calculated using different oscillation codes for a given stellar model

In order to make astroseismology a powerful tool to explore stellar interiors, different numerical codes should give the same oscillation frequencies for the same input physics. This work is devoted to test, compare and, if needed, optimize the seismic codes used to calculate the eigenfrequencies to be finally compared with observations. The oscillation codes of nine research groups in the field have been used in this study. The same physics has been imposed for all the codes in order to isolate the non-physical dependence of any possible difference. Two equilibrium models with different grids, 2172 and 4042 mesh points, have been used, and the latter model includes an explicit modelling of semiconvection just outside the convective core. Comparing the results for these two models illustrates the effect of the number of mesh points and their distribution in particularly critical parts of the model, such as the steep composition gradient outside the convective core. A comprehensive study of the frequency differences found for the different codes is given as well. These differences are mainly due to the use of different numerical integration schemes. The use of a second-order integration scheme plus a Richardson extrapolation provides similar results to a fourth-order integration scheme. The proper numerical description of the Brunt-Vaisala frequency in the equilibrium model is also critical for some modes. An unexpected result of this study is the high sensitivity of the frequency differences to the inconsistent use of values of the gravitational constant (G) in the oscillation codes, within the range of the experimentally determined ones, which differ from the value used to compute the equilibrium model.Comment: 18 pages, 34 figure

Measurement of the Bottom-Strange Meson Mixing Phase in the Full CDF Data Set

We report a measurement of the bottom-strange meson mixing phase \beta_s using the time evolution of B0_s -> J/\psi (->\mu+\mu-) \phi (-> K+ K-) decays in which the quark-flavor content of the bottom-strange meson is identified at production. This measurement uses the full data set of proton-antiproton collisions at sqrt(s)= 1.96 TeV collected by the Collider Detector experiment at the Fermilab Tevatron, corresponding to 9.6 fb-1 of integrated luminosity. We report confidence regions in the two-dimensional space of \beta_s and the B0_s decay-width difference \Delta\Gamma_s, and measure \beta_s in [-\pi/2, -1.51] U [-0.06, 0.30] U [1.26, \pi/2] at the 68% confidence level, in agreement with the standard model expectation. Assuming the standard model value of \beta_s, we also determine \Delta\Gamma_s = 0.068 +- 0.026 (stat) +- 0.009 (syst) ps-1 and the mean B0_s lifetime, \tau_s = 1.528 +- 0.019 (stat) +- 0.009 (syst) ps, which are consistent and competitive with determinations by other experiments.Comment: 8 pages, 2 figures, Phys. Rev. Lett 109, 171802 (2012

Characterization of a new platelet aggregating factor from crotoxin Crotalus durissus cascavella venom

FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ – CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOIn this article we investigated the platelet aggregating activity of whole crotoxin and its subunits isolated from Crotalus durissus cascavella venom. During the purification protocols of the venom, using HPLC molecular exclusion, we detected the presence of two different serine protease activities in the gyroxin fraction, and another in the crotoxin fraction, which induced strong and irreversible platelet aggregation, in addition to blood coagulation. From crotoxin, we isolated PLA(2), crotapotin (both fractions corresponding approximately 85% of whole crotoxin) and another minor fraction (F20) that exhibited serine protease activity. After a new fractionation on reverse phase HPLC chromatography, we obtained three other fractions named as F201, F202 and F203. F202 was obtained with high degree of molecular homogeneity with molecular mass of approximately 28 kDa and a high content of acidic amino residues, such as aspartic acid and glutamic acid. Other important amino acids were histidine, cysteine and lysine. This protein exhibited a high specificity for BApNA, a Michaelis-Menten behavior with Vmax estimated in 5.64 mu M/min and a Km value of 0.58 mM for this substrate. In this work, we investigated the ability of F202 to degrade fibrinogen and observed alpha and beta chain cleavage. Enzymatic as well as the platelet aggregation activities were strongly inhibited when incubated with TLCK and PMSF, specific inhibitors of serine protease. Also, F202 induced platelet aggregation in washed and platelet-rich plasma, and in both cases, TLCK inhibited its activity. The N-terminal amino acid sequence of F202 presented a high amino acid sequence homology with other thrombin-like proteins, but it was significantly different from gyroxin. These results showed that crotoxin is a highly heterogeneous protein composed of PLA(2), thrombin-like and other fractions that might explain the diversity of physiological and pharmacological activities of this proteinSpringer253183192FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ – CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ – CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO2004/00040-3300211.2004New York, N

EARLY GROWTH AND SEEDLING MORPHOLOGY OF SPECIES OF Sesbania Scop. (Leguminosae, robinieae) DESENVOLVIMENTO INICIAL E CARACTERIZAÇÃO DAS PLÂNTULAS DE ESPÉCIES DE Sesbania SCOP. (LEGUMINOSAE, ROBINIEAE)

The objective of this study was to characterize 17 accessions of Sesbania, representing S. exasperata, S. grandiflora, S. sesban, S. tetraptera and S. virgata at the seedling stage, and to evaluate the initial development during the first two months after planting. The trial was conducted in a greenhouse in a randomized block design, with 4 replications and 5 plants per plot. The traits recorded were: plant height (PH), from four observations at 15-day intervals, at 17, 32, 47 and 62 days after planting; length of hypocotyl (LH) and epicotyl (LEP); length (LE1) and width (WE1) of the first eophyll; and number of leaflet pairs of the second metaphyll (NLP), evaluated 17 days after planting. Univariate analyses of variance were performed, estimating the genetic parameters: coefficient of genotypic determination (b) and of genetic variation (CVg). Cluster analysis was also obtained, using the average Euclidean distance and Unweighted pair group method of arithmetic average (UPGMA) method. At 17 days after planting, S. exasperata presented the highest PH, followed by S. virgata. At 62 days after planting, S. sesban registered the highest PH. Length of hypocotyl displayed inter but not intraspecific variation. The characters LEP, LE1, WE1 and NLP showed both inter and intraspecific variation. Cluster analysis indicated the existence of 7 groups, separating the species and revealing intraspecific variation as well. The occurrence in low frequencies of two unifoliolate opposite eophylls for some species was observed, as well as bi- or trifoliolate first eophylls for one of the S. sesban accessions. These informations are basic for the selection of traits to be utilized for characterization and differentiation of Sesbania germplasm at the juvenile phase.<br>Este estudo teve como objetivo caracterizar 17 acessos de Sesbania, representando as espécies S. exasperata, S. grandiflora, S. sesban, S. tetraptera e S. virgata no estágio de plântula, avaliando também o desenvolvimento inicial nos primeiros dois meses após o plantio. O ensaio foi instalado em casa-de-vegetação, em blocos casualizados com 4 repetições e 5 plantas por parcela. Avaliaram-se os seguintes caracteres: altura da planta (AP) em 4 avaliações, espaçadas de 15 dias, aos 17, 32, 47 e 62 dias após o plantio; comprimento do hipocótilo (CH) e do epicótilo (CEP); comprimento (CE1) e largura (LE1) do eófilo 1; e número de pares de folíolos do metáfilo 2 (NPF). A primeira AP e os demais caracteres foram avaliados aos 17 dias do plantio. Foram realizadas análises de variância univariada, estimando-se os parâmetros genéticos: coeficiente de determinação genotípica (b) e de variação genética (CVg), e uma análise de agrupamento, usando distância Euclideana média e método UPGMA (Unweighted pair group method of arithmetic average). Aos 17 dias do plantio, S. exasperata apresentou maior AP, seguida de S. virgata. Aos 62 dias do plantio, S. sesban apresentou a maior AP. O caráter CH apresentou variação inter mas não intraespecífica. Já os caracteres CEP, CE1, LE1 e NPF mostraram variação tanto inter como intraespecífica. A análise de agrupamento indicou a existência de 7 grupos, separando as espécies e mostrando variação intraespecífica. Foi também observada a ocorrência, em baixas freqüências, de dois eófilos unifoliolados e opostos para algumas espécies, bem como a ocorrência de eófilos nº 1 bi- ou trifoliolados para um dos acessos de S. sesban. Estas informações são básicas para a escolha de caracteres a serem utilizados na fase juvenil para a diferenciação e caracterização de germoplasma de Sesbania