15,288 research outputs found

    Extension of Tycho catalog for low-extinction windows in the galactic bulge

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    We present in this work secondary catalogs up to mValāˆ¼13m_{Val} \sim 13 based on the Tycho reference frame (ESA, 1997) for 12 selected low-extinction fields towards the galactic bulge. The observations have been performed with the Askania-Zeiss Meridian Circle equiped with a CCD camera, located at the Abrah\~ao de Moraes Observatory (Valinhos, Brazil) and operated by the Institute of Astronomy and Geophysics, S\~ao Paulo University. The presented catalog, though not complete, has been designed to help in intensive search programmes (e.g. microlensing and variable searches) and therefore the selected standards have a high astrometric and photometric (VV band, approximately) quality. The mean precisions obtained were 0.0018s0.0018^{s} in Ī±\alpha, 0.013'' in Ī“\delta, 0.030 for the standard deviation in magnitude and 0.0042 for the magnitude when weighted with the error bars in each night (in the mean, 42 stars for the catalog of each window). Tables B.1 to B.12 are also available in eletronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html.Comment: 16 pages, 6 figures, A&A Latex style. Published in A&A

    Stellar variability in low-extinction regions towards the Galactic Bulge

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    Intensive monitoring of low-extinction windows towards the galactic bulge has provided in the last years valuable information for studies about the dynamics, kinematics and formation history of this part of the galaxy, mainly by characterizing the bulge stellar populations (Paczy\'nski, 1996). Since 1997, we have been conducting an intensive photometric-astrometric survey of the galactic bulge, with the monitoring of about 120000 stars in 12 windows uniformly distributed in galactic latitude and longitude (Blanco & Terndrup, 1989 e Blanco, 1988) never before submitted to this kind of survey. For this purpose, we have used the IAG/USP CCD Meridian Circle of the Abrah\~ao de Moraes Observatory. The main objective of this work is the identification and classification of variable objects. In this work we present the set up and development of the necessary tools for a project like this and the posterior analysis of our data. We briefly describe the construction of a program to organize and detect variables among the observed stars, including real time alerts (for variations greater than 0.3 magnitudes). The preliminary analysis after the processing of 76 nights of observation yielded 479 variable stars, from which 96.7 % of them are new. We discuss the preliminary classification of this variables, based on: a) the observed amplitude of variation; b) the shape of light curve; c) the expected variable classes among our data and d) the calculated periods, whenever possible. Finally, we discuss the future perspectives for the project and for the applications and analysis of the discovered variable stars.Comment: 10 pages, 14 figures. Accepted by A&A

    Genetic gain in an improvement program of irrigated rice in Minas Gerais.

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    An evaluation of the genetic improvement programme of irrigated rice of Minas Gerais (Brazil) estimated the genetic gain obtained in the 90s. Grain yield data of the advanced comparative trials of cultivars and lines of continuously flooded rice, conducted from 1990-91 to 2000-01, were used. The estimate of the genetic gain was obtained by the methodology of the adjusted means proposed by Breseghello (1998). The mean annual genetic gain in the 90s was 42.45+or-17.89 kg ha-1 (0.7% per year). The improvement programme proved auspicious for the development of lines that outmatched the controls. The mean of the cultivars released in the 90s did however not outstrip the mean of the elite lines, which were the genotypes with the highest means in this study and will be further evaluated in the ongoing programme

    Combining exclusive semi-leptonic and hadronic B decays to measure |V_ub|

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    The Cabibbo-Kobayashi-Maskawa matrix element |V_ub| can be extracted from the rate for the semi-leptonic decay B -> pi + l + antineutrino_l, with little theoretical uncertainty, provided the hadronic form factor for the B -> pi transition can be measured from some other B decay. In here, we suggest using the decay B -> pi J\psi. This is a color suppressed decay, and it cannot be properly described within the usual factorization approximation; we use instead a simple and very general phenomenological model for the b d J\psi vertex. In order to relate the hadronic form factors in the B -> pi J\psi and B -> pi + l + antineutrino_l decays, we use form factor relations that hold for heavy-to-light transitions at large recoil.Comment: Latex, 7 pages, no figure

    Sistema de produĆ§Ć£o de leite em RondĆ“nia: produĆ§Ć£o, reproduĆ§Ć£o, nutriĆ§Ć£o e alimentaĆ§Ć£o.

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    Esta publicaĆ§Ć£o apresenta um estudo sobre a produĆ§Ć£o leiteira no Estado de RO e propƵe aƧƵes otimizadoras da produĆ§Ć£o.bitstream/item/24795/1/rt91-sistemadeproducaodeleite.pd

    Rapid prototyping and tooling in the manufacture of mould elements for large parts

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    In the last two decades the advances in rapid prototyping and tooling (RPT) technologies made possible the use of materials alternative to steel in some mould components. They also have allowed novel fabrication strategies and new ways of thinking on the production of injection moulds for short series of plas-tics parts. These technologies induced a new generation of toolmaking techniques. In the scope of the devel-opment project Hybridmould 21 the pros and cons of some RPT technologies were studied to fabricate moulding blocks and inserts for hybrid injection moulds for large plastics parts. Essentially, the studies aimed at finding the best solution for quick production and compliance with specific product requirements, such as complex features, complex cooling layout and large size (around 1 m2) in short production series. This paper discusses the main advantages and disadvantages associated to a number of different RPT technologies for the manufacture of moulding element.Program QREN - ā€˜ConcessĆ£o de Incentivos Financeiros no Ć¢mbito do Sistema de Incentivos Ć  InvestigaĆ§Ć£o e Desenvolvimento TecnolĆ³gicoā€™ (contract 2010/013307) ā€“ Project Hybridmould 2
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