788 research outputs found

    Alignment tests for low CMB multipoles

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    We investigate the large scale anomalies in the angular distribution of the cosmic microwave background radiation as measured by WMAP using several tests. These tests, based on the multipole vector expansion, measure correlations between the phases of the multipoles as expressed by the directions of the multipole vectors and their associated normal planes. We have computed the probability distribution functions for 46 such tests, for the multipoles l=2-5. We confirm earlier findings that point to a high level of alignment between l=2 (quadrupole) and l=3 (octopole), but with our tests we do not find significant planarity in the octopole. In addition, we have found other possible anomalies in the alignment between the octopole and the l=4 (hexadecupole) components, as well as in the planarity of l=4 and l=5. We introduce the notion of a total likelihood to estimate the relevance of the low-multipoles tests of non-gaussianity. We show that, as a result of these tests, the CMB maps which are most widely used for cosmological analysis lie within the ~ 10% of randomly generated maps with lowest likelihoods.Comment: References added, updated discussion on alignment with Ecliptic Plane. 12 Pages, 6 Figures. Results for additional maps, the normalized frequencies for the tests and a Mathematica Notebook that computes the tests can be found on http://fma.if.usp.br/~abramo/MVA.htm

    Spillover and diffraction sidelobe contamination in a double-shielded experiment for mapping Galactic synchrotron emission

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    We have analyzed observations from a radioastronomical experiment to survey the sky at decimetric wavelengths along with feed pattern measurements in order to account for the level of ground contamination entering the sidelobes. A major asset of the experiment is the use of a wire mesh fence around the rim-halo shielded antenna with the purpose of levelling out and reducing this source of stray radiation for zenith-centered 1-rpm circular scans. We investigate the shielding performance of the experiment by means of a geometric diffraction model in order to predict the level of the spillover and diffraction sidelobes in the direction of the ground. Using 408 MHz and 1465 MHz feed measurements, the model shows how a weakly-diffracting and unshielded antenna configuration becomes strongly-diffracting and double-shielded as far-field diffraction effects give way to near-field ones. Due to the asymmetric response of the feeds, the orientation of their radiation fields with respect to the secondary must be known a priori before comparing model predictions with observational data. By adjusting the attenuation coefficient of the wire mesh the model is able to reproduce the amount of differential ground pick-up observed during test measurements at 1465 MHz.Comment: 14 pages, 17 eps + 1 gif figures and 4 Tables. Accepted for publication in A&AS. Fig.7 available at full resolution from http://www.das.inpe.br/~tello/publications.ht

    Biomassa arbórea em fragmentos da Mata Atlântica Fluminense.

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    Na Mata Atlântica do Sudeste Brasileiro persistem florestas em apenas 11,8% da superfície original nessa região. A fragmentação é contínua gerando impactos sobre o acúmulo de biomassa. Esta tem relevância ambiental, dado o interesse no desenvolvimento de modelos preditivos dos estoques terrestres de carbono em todas as latitudes ante às crescentes emissões de gases de efeito estufa. Tendo em vista a carência de estimativas relativas aos fragmentos de pequenas dimensões (< 50 ha), objetivou-se no presente estudo estimar a biomassa arbórea acima do solo de três amostras da Baixada Litorânea Fluminense inseridos na Área de Proteção Ambiental Rio São João. Utilizou-se equação alométrica com entradas de diâmetro a 1,30 m do solo (DAP) e a densidade específica da madeira. Os resultados obtidos (119 a 190 Mg.ha-1) evidenciaram proximidade e distância em relação a outras estimativas de biomassa da Mata Atlântica, sugerindo a necessidade do desenvolvimento de equações alométricas específicas para os ecossistemas representativos deste bioma.bitstream/CNPS-2009-09/14048/1/bpd127_biomassa_arborea.pd

    Levantamento dos dados de passaporte e caracterização de acessos do banco ativo de germoplasma de capsicum da Embrapa clima temperado.

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    O Brasil é um importante centro secundário de espécies domesticadas de pimentas do gênero Capsicum. Muitos agricultores cultivam as variedades crioulas de Capsicum, que são resultados de vários ciclos de seleção por eles realizada. Estes recursos genéticos vêm sofrendo ação da erosão genética, devido à substituição de culturas ou abandono da atividade agrícola. Em função da grande importância de conservar esse germoplasma, a Embrapa Clima Temperado (Pelotas, RS) vem desde 2002 realizando o resgate de variedades locais de Capsicum, as quais são conservadas no Banco Ativo de Germoplasma (BAG) de Capsicum. O presente trabalho tem como objetivo apresentar a situaçãoatual do Banco Ativo de Germoplasma de Capsicum da Embrapa Clima Temperado, com base no levantamento dos dados de passaporte e de caracterização dos acessos. O BAG de Capsicum da Embrapa Clima Temperado mantém em seu acervo 324 acessos, a maioria deles proveniente de coletas realizadas no Rio Grande do Sul. Fazem parte do acervo do banco acessos de C. annuum, C. baccatum, C. frutescens, C. chinense, C. pubescens, C. galapagoense e C. lanceolatum. Foram submetidos à caracterização morfológica 51,2 % dos acessos, à caracterização química 14,8% e à caracterização molecular 6,1%. Foram avaliados agronomicamente 5,5% dos acessos. Os resultados obtidos demonstram que o BAG de Capsicum da Embrapa Clima Temperado reúne importante diversidade genética de variedades crioulas de pimentas, o que evidencia a importância desse banco

    ARCADE 2 Measurement of the Extra-Galactic Sky Temperature at 3-90 GHz

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    The ARCADE 2 instrument has measured the absolute temperature of the sky at frequencies 3, 8, 10, 30, and 90 GHz, using an open-aperture cryogenic instrument observing at balloon altitudes with no emissive windows between the beam-forming optics and the sky. An external blackbody calibrator provides an {\it in situ} reference. Systematic errors were greatly reduced by using differential radiometers and cooling all critical components to physical temperatures approximating the CMB temperature. A linear model is used to compare the output of each radiometer to a set of thermometers on the instrument. Small corrections are made for the residual emission from the flight train, balloon, atmosphere, and foreground Galactic emission. The ARCADE 2 data alone show an extragalactic rise of 50±750\pm7 mK at 3.3 GHz in addition to a CMB temperature of 2.730±.0042.730\pm .004 K. Combining the ARCADE 2 data with data from the literature shows a background power law spectrum of T=1.26±0.09T=1.26\pm 0.09 [K] (ν/ν0)2.60±0.04(\nu/\nu_0)^{-2.60\pm 0.04} from 22 MHz to 10 GHz (ν0=1\nu_0=1 GHz) in addition to a CMB temperature of 2.725±.0012.725\pm .001 K.Comment: 11 pages 5 figures Submitted to Ap

    Tuberculosis/HIV/AIDS coinfection in Porto Alegre, RS/Brazil - invisibility and silencing of the most affected groups

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    OBJECTIVE: To analyze how belonging to certain social groups contributes to constituting the vulnerabilities associated with illnesses due to tuberculosis/HIV/AIDS coinfection. METHODOLOGYThis is a qualitative study carried out in the city of Porto Alegre, state of Rio Grande do Sul, in regions of high social vulnerability. Twenty coinfected people were interviewed in specialized health services between August and December 2016. The analysis was based on the frameworks The Sound of Silence and Vulnerability and Human Rights. RESULTS: Socioeconomic conditions were decisive for the constitution of the vulnerability conditions. Processes of people invisibilization, and the silencing of their voices, in a scenario marked by economic, racial and gender inequalities, contributed for their health needs not to be understood and effectively taken into account in the services actions. FINAL CONSIDERATIONS: The more effective strategies are to legitimize voices and to understand the needs of those affected by coinfection, the greater the chances that programmatic responses to the problem will be successful

    Depletion of angiotensin-converting enzyme 2 reduces brain serotonin and impairs the running-induced neurogenic response

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    This is the author accepted manuscript. The final version is available from the publisher via the DOI in this recordPhysical exercise induces cell proliferation in the adult hippocampus in rodents. Serotonin (5-HT) and angiotensin (Ang) II are important mediators of the pro-mitotic effect of physical activity. Here, we examine precursor cells in the adult brain of mice lacking angiotensin-converting enzyme (ACE) 2, and explore the effect of an acute running stimulus on neurogenesis. ACE2 metabolizes Ang II to Ang-(1-7) and is essential for the intestinal uptake of tryptophan (Trp), the 5-HT precursor. In ACE2-deficient mice, we observed a decrease in brain 5-HT levels and no increase in the number of BrdU-positive cells following exercise. Targeting the Ang II/AT1 axis by blocking the receptor, or experimentally increasing Trp/5-HT levels in the brain of ACE2-deficient mice, did not rescue the running-induced effect. Furthermore, mice lacking the Ang-(1-7) receptor, Mas, presented a normal neurogenic response to exercise. Our results identify ACE2 as a novel factor required for exercise-dependent modulation of adult neurogenesis and essential for 5-HT metabolism
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