22,744 research outputs found

    Science with the World Space Observatory - Ultraviolet

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    The World Space Observatory-Ultraviolet (WSO-UV) will provide access to the UV range during the next decade. The instrumentation on board will allow to carry out high resolution imaging, high sensitivity imaging, high resolution (R~55000) spectroscopy and low resolution (R~2500) long slit spectroscopy. In this contribution, we briefly outline some of the key science issues that WSO-UV will address during its lifetime. Among them, of special interest are: the study of galaxy formation and the intergalactic medium; the astronomical engines; the Milky Way formation and evol ution, and the formation of the Solar System and the atmospheres of extrasolar p lanets.Comment: Just one text file (aigomezdecastro.tex). To be published in the proceeding of the conference: "New Quest in Stellar Astrophysics II: UV properties of evolved stellar populations" held in Puerto Vallarta - Mexico, in april 200

    Automatic learning of gait signatures for people identification

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    This work targets people identification in video based on the way they walk (i.e. gait). While classical methods typically derive gait signatures from sequences of binary silhouettes, in this work we explore the use of convolutional neural networks (CNN) for learning high-level descriptors from low-level motion features (i.e. optical flow components). We carry out a thorough experimental evaluation of the proposed CNN architecture on the challenging TUM-GAID dataset. The experimental results indicate that using spatio-temporal cuboids of optical flow as input data for CNN allows to obtain state-of-the-art results on the gait task with an image resolution eight times lower than the previously reported results (i.e. 80x60 pixels).Comment: Proof of concept paper. Technical report on the use of ConvNets (CNN) for gait recognition. Data and code: http://www.uco.es/~in1majim/research/cnngaitof.htm

    The formation of planetary disks and winds: an ultraviolet view

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    Planetary systems are angular momentum reservoirs generated during star formation. This accretion process produces very powerful engines able to drive the optical jets and the molecular outflows. A fraction of the engine energy is released into heating thus the temperature of the engine ranges from the 3000K of the inner disk material to the 10MK in the areas where magnetic reconnection occurs. There are important unsolved problems concerning the nature of the engine, its evolution and the impact of the engine in the chemical evolution of the inner disk. Of special relevance is the understanding of the shear layer between the stellar photosphere and the disk; this layer controls a significant fraction of the magnetic field building up and the subsequent dissipative processes ougth to be studied in the UV. This contribution focus on describing the connections between 1 Myr old suns and the Sun and the requirements for new UV instrumentation to address their evolution during this period. Two types of observations are shown to be needed: monitoring programmes and high resolution imaging down to, at least, milliarsecond scales.Comment: Accepted for publication in Astrophysics and Space Science 9 figure

    Marcadores microssatélites para monitorar a eficiência da estratégia de conservação de Passiflora edulis Sims.

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    Um Banco Ativo de Germoplasma (BAG) tem o importante papel na preservação da variabilidade genética. No entanto, se a diversidade interespecífica, intraespecífica e intra-acesso no BAG não forem preservadas ao longo do tempo, ele não atingirá a finalidade proposta.Em paralelo aconteceram também os seguintes eventos: V Seminário de Pesquisa do Recôncavo da Bahia; V Seminário Estudantil de Pesquisa da UFRB; V Seminário da Pós-Graduação da UFRB; II Seminário Regional de Pesquisa da EBDA; 5ª Jornada Científica da Embrapa Mandioca e Fruticultura; VIII Seminário Estudantil de Pesquisa e Extensão da FAMAM; Semana de Ciência, Tecnologia e Inovação no Agronegócio; Fórum de Gestores de Iniciação Científica e Tecnológica da Bahia; II Simpósio Baiano de Defesa Agropecuária; I Semana de Educação Tutorial da UFRB

    Toward a test of angular momentum coherence in a twin-atom interferometer

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    We present a scheme well-suited to investigate quantitatively the angular momentum coherence of molecular fragments. Assuming that the dissociated molecule has a null total angular momentum, we investigate the propagation of the corresponding atomic fragments in the apparatus. We show that the envisioned interferometer enables one to distinguish unambiguously a spin-coherent from a spin-incoherent dissociation, as well as to estimate the purity of the angular momentum density matrix associated with the fragments. This setup, which may be seen as an atomic analogue of a twin-photon interferometer, can be used to investigate the suitability of molecule dissociation processes -- such as the metastable hydrogen atoms H(22S2^2 S)-H(22S2^2 S) dissociation - for coherent twin-atom optics.Comment: 6 pages, 3 Figures. Final version accepted for publication in Europhysics Letter

    Agriculturas de base ecológica na comunidade Barreira do Andirá.

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    Este trabalho teve como objetivo caracterizar e sistematizar agriculturas de base ecológica na comunidade Barreira do Andirá. Utilizando metodologia adequada e participativa, foram observadas algumas agriculturas como o uso de sistemas agroflorestais com a cultura principal sendo o guaraná, Paullinia cupana e a criação de abelhas meliponeas

    Chemical abundances and kinematics of barium stars

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    In this paper we present an homogeneous analysis of photospheric abundances based on high-resolution spectroscopy of a sample of 182 barium stars and candidates. We determined atmospheric parameters, spectroscopic distances, stellar masses, ages, luminosities and scale height, radial velocities, abundances of the Na, Al, alphaalpha-elements, iron-peak elements, and s-process elements Y, Zr, La, Ce, and Nd. We employed the local-thermodynamic-equilibrium model atmospheres of Kurucz and the spectral analysis code {\sc moog}. We found that the metallicities, the temperatures and the surface gravities for barium stars can not be represented by a single gaussian distribution. The abundances of alphaalpha-elements and iron peak elements are similar to those of field giants with the same metallicity. Sodium presents some degree of enrichment in more evolved stars that could be attributed to the NeNa cycle. As expected, the barium stars show overabundance of the elements created by the s-process. By measuring the mean heavy-element abundance pattern as given by the ratio [s/Fe], we found that the barium stars present several degrees of enrichment. We also obtained the [hs/ls] ratio by measuring the photospheric abundances of the Ba-peak and the Zr-peak elements. Our results indicated that the [s/Fe] and the [hs/ls] ratios are strongly anti-correlated with the metallicity. Our kinematical analysis showed that 90% of the barium stars belong to the thin disk population. Based on their luminosities, none of the barium stars are luminous enough to be an AGB star, nor to become self-enriched in the s-process elements. Finally, we determined that the barium stars also follow an age-metallicity relation.Comment: 30 pages, 26 figures, 18 tables, accepted for publication in MNRA

    The earliest spectroscopy of the GRB 030329 afterglow with 6-m telescope

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    The earliest BTA (SAO RAS 6-m telescope) spectroscopic observations of the GRB 030329 optical transient (OT) are presented, which almost coincide in time with the "first break" (t0.5t\sim 0.5 day after the GRB) of the OT light curve. The beginning of spectral changes are seen as early as 1012\sim 10-12 hours after the GRB. So, the onset of the spectral changes for t<1t<1 day indicates that the contribution from Type Ic supernova (SN) into the OT optical flux can be detected earlier. The properties of early spectra of GRB 030329/SN 2003dh can be consistent with a shock moving into a stellar wind formed from the pre-SN. Such a behavior (similar to that near the UV shock breakout in SNe) can be explained by the existence of a dense matter in the immediate surroundings of massive stellar GRB/SN progenitor). The urgency is emphasized of observation of early GRB/SN spectra for solving a question that is essential for understanding GRB physical mechanism: {\it Do all} long-duration gamma-ray bursts are caused by (or physically connected to) {\it ordinary} core-collapse supernovae? If clear association of normal/ordinary core-collapse SNe (SN Ib/c, and others SN types) and GRBs would be revealed in numbers of cases, we may have strong observational limits for gamma-ray beaming and for real energetics of the GRB sources.Comment: 4 pages, 5 figures. Proceedings of the 4th Workshop "Gamma-Ray Bursts in the Afterglow Era", Roma, 2004 October 18-22, eds. L. Piro, L. Amati, S. Covino, and B. Gendre. Il Nuovo Cimento, in pres

    A tecnologia vídeo digital na educação: fator de inclusão ou de exclusão?

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    A convergência das mídias em uma plataforma que reúne sons, imagens e dados, com recursos de interatividade e portabilidade, oferece novas possibilidades educomunicacionais. Este artigo foi desenvolvido para conclusão da disciplina Desenvolvimento de Conteúdo Educacional baseado na TV Digital Interativa, do programa de pós-graduação da Faculdade de Educação da Unicamp, com o objetivo de discutir o papel do vídeo digital no processo de ensino-aprendizagem e os fatores de inclusão e de exclusão que podem estar envolvidos. A adoção do vídeo digital na sala de aula pode fazer parte de um plano de atividades pedagógicas, ampliando os espaços para a aprendizagem, a reflexão e a construção de conhecimento de forma coletiva. Para que isso aconteça, os estudos mostram que o uso das novas tecnologias de informação e comunicação deve ser pensado estrategicamente para que estimule o aluno a pensar a sua realidade e a apropriar-se dos mecanismos que permitam transformá-la, superando o papel de mero receptor para o de produtor de conhecimento e de conteúdos digitais interativos

    Utilização do taxi-branco (Sclerolobium paniculatum Vogel) para recuperação de solos degradados pela agricultura migratória.

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    O objetivo deste trabalho foi de avaliar a dinâmica da materia organica e de nutrientes em duas áreas abandonadas: uma plantada com taxi branco e outra com capoeira sem enriquecimento
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