1,027 research outputs found

    Biomassa, morfologia e curva de crescimento de cinco genótipos de Pfaffia glomerata em condição de estufa

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    Monografia (graduação)—Universidade de Brasília, Faculdade de Agronomia e Medicina Veterinária, 2012.As raízes de Pfaffia glomerata (Spreng.) Pedersen, espécie perene, de porte arbustivo pertencente à família Amaranthaceae, são de grande interesse comercial, tanto na forma de fito-medicamentos, quanto de suplementos alimentares. É uma espécie nativa da América do Sul e de ocorrência comum nos Estados do Paraná, Mato Grosso do Sul e Goiás. O objetivo do presente trabalho foi obter a curva de crescimento de cinco genótipos de Pfaffia glomerata obtidos a partir da autosemeadura ocorrida na coleção de acessos da UnB, determinar a produção de biomassa da parte aérea e da raiz e descrever sua morfologia externa. O ensaio foi feito em estufa do tipo Glasshouse. As temperaturas médias das mínimas e das máximas durante os meses de ensaio foram respectivamente 20.1º C e 35,5 ºC. A partir das cinco plântulas oriundas da autosemeadura foram obtidas estacas uninodais que foram crescidas em miniestufa e ao enraizarem e atingirem em média 10 cm de altura, foram transplantadas para vasos de 2L de capacidade contendo mistura de solo adubado e dispostos sobre bancadas de cimento na estufa do tipo Glasshouse. Durante oito semanas após o transplante, foi medida semanalmente a altura da planta, desde o nível do coleto até o broto mais elevado e, ao final do ensaio foi obtida a massa fresca das raízes e a massa fresca da parte aérea. Foram anotadas as características morfológicas das plantas para acessar a diversidade neste item, compreendendo a morfologia do limbo foliar, a cor do talo e a pilosidade e a emissão floral. O crescimento das plantas de P. glomerata em condição de estufa apresentou-se compatível com o padrão da cultura. As plantas oriundas da auto-semeadura apresentaram elevada segregação de caracteres morfológicos

    Confirmation detection in human-agent interaction using non-lexical speech cues

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    Brandt M, Wrede B, Kummert F, Schillingmann L. Confirmation detection in human-agent interaction using non-lexical speech cues. Presented at the AAAI Symposium on Natural Communication for Human-Robot Collaboration, Arlington, VA.Even if only the acoustic channel is considered, human communication is highly multi-modal. Non-lexical cues provide a variety of information such as emotion or agreement. The ability to process such cues is highly relevant for spoken dialog systems, especially in assistance systems. In this paper we focus on the recognition of non-lexical confirmations such as "mhm", as they enhance the system's ability to accurately interpret human intent in natural communication. The architecture uses a Support Vector Machine to detect confirmations based on acoustic features. In a systematic comparison, several feature sets were evaluated for their performance on a corpus of human-agent interaction in a setting with naive users including elderly and cognitively impaired people. Our results show that using stacked formants as features yield an accuracy of 84% outperforming regular formants and MFCC or pitch based features for online classification

    The lack of star formation gradients in galaxy groups up to z~1.6

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    In the local Universe, galaxy properties show a strong dependence on environment. In cluster cores, early type galaxies dominate, whereas star-forming galaxies are more and more common in the outskirts. At higher redshifts and in somewhat less dense environments (e.g. galaxy groups), the situation is less clear. One open issue is that of whether and how the star formation rate (SFR) of galaxies in groups depends on the distance from the centre of mass. To shed light on this topic, we have built a sample of X-ray selected galaxy groups at 0<z<1.6 in various blank fields (ECDFS, COSMOS, GOODS). We use a sample of spectroscopically confirmed group members with stellar mass M >10^10.3 M_sun in order to have a high spectroscopic completeness. As we use only spectroscopic redshifts, our results are not affected by uncertainties due to projection effects. We use several SFR indicators to link the star formation (SF) activity to the galaxy environment. Taking advantage of the extremely deep mid-infrared Spitzer MIPS and far-infrared Herschel PACS observations, we have an accurate, broad-band measure of the SFR for the bulk of the star-forming galaxies. We use multi-wavelength SED fitting techniques to estimate the stellar masses of all objects and the SFR of the MIPS and PACS undetected galaxies. We analyse the dependence of the SF activity, stellar mass and specific SFR on the group-centric distance, up to z~1.6, for the first time. We do not find any correlation between the mean SFR and group-centric distance at any redshift. We do not observe any strong mass segregation either, in agreement with predictions from simulations. Our results suggest that either groups have a much smaller spread in accretion times with respect to the clusters and that the relaxation time is longer than the group crossing time.Comment: Accepted for publication in MNRA

    The Sloan Digital Sky Survey Reverberation Mapping Project: the XMM-Newton X-ray source catalog and multi-band counterparts

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    The XMM-RM project was designed to provide X-ray coverage of the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) field. 41 XMM-Newton exposures, placed surrounding the Chandra AEGIS field, were taken, covering an area of 6.13 deg^2 and reaching a nominal exposure depth of ~15 ks. We present an X-ray catalog of 3553 sources detected in these data, using a PSF-fitting algorithm and a sample selection threshold that produces a ~5% fraction of spurious sources. In addition to the PSF-fitting likelihood, we calculate a second source reliability measure based on Poisson theory using source and background counts within an aperture. Using the Poissonian likelihood, we select a sub-sample with a high purity and find that it has similar number count profiles to previous X-ray surveys. The Bayesian method "NWAY" was employed to identify counterparts of the X-ray sources from the optical Legacy and the IR unWISE catalogs, using a 2-dimensional unWISE magnitude-color prior created from optical/IR counterparts of Chandra X-ray sources. A significant number of the optical/IR counterparts correspond to sources with low detection likelihoods, proving the value of retaining the low-likelihood detections in the catalog. 932 of the XMM-RM sources are covered by SDSS spectroscopic observations. 89% of them are classified as AGN, and 71% of these AGN are in the SDSS-RM quasar catalog. Among the SDSS-RM quasars, 80% are detectable at the depth of the XMM observations.Comment: ApJS accepted. 20 pages, 16 figure

    The COSMOS AGN Spectroscopic Survey I: XMM Counterparts

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    We present optical spectroscopy for an X-ray and optical flux-limited sample of 677 XMM-Newton selected targets covering the 2 deg^2 COSMOS field, with a yield of 485 high-confidence redshifts. The majority of the spectra were obtained over three seasons (2005-2007) with the IMACS instrument on the Magellan (Baade) telescope. We also include in the sample previously published Sloan Digital Sky Survey spectra and supplemental observations with MMT/Hectospec. We detail the observations and classification analyses. The survey is 90% complete to flux limits of f_{0.5-10 keV}>8 x 10^-16 erg cm^-2 s^-1 and i_AB+<22, where over 90% of targets have high-confidence redshifts. Making simple corrections for incompleteness due to redshift and spectral type allows for a description of the complete population to $i_AB+<23. The corrected sample includes 57% broad emission line (Type 1, unobscured) AGN at 0.13<z<4.26, 25% narrow emission line (Type 2, obscured) AGN at 0.07<z<1.29, and 18% absorption line (host-dominated, obscured) AGN at 0<z<1.22 (excluding the stars that made up 4% of the X-ray targets). We show that the survey's limits in X-ray and optical flux include nearly all X-ray AGN (defined by L_{0.5-10 keV}>3 x 10^42 erg s^-1) to z<1, of both optically obscured and unobscured types. We find statistically significant evidence that the obscured to unobscured AGN ratio at z<1 increases with redshift and decreases with luminosity.Comment: Accepted for publication in the ApJ. 31 pages, 17 figures. Table 2 is available on reques

    A comparative analysis of virial black hole mass estimates of moderate-luminosity active galactic nuclei using Subaru/FMOS

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    We present an analysis of broad emission lines observed in moderate-luminosity active galactic nuclei (AGNs), typical of those found in X-ray surveys of deep fields, with the goal of testing the validity of single-epoch virial black hole mass estimates. We have acquired near-infrared spectra of AGNs up to z ~ 1.8 in the COSMOS and Extended Chandra Deep Field-South Survey, with the Fiber Multi-Object Spectrograph mounted on the Subaru telescope. These near-infrared spectra provide a significant detection of the broad Hα line, shown to be a reliable probe of black hole mass at low redshift. Our sample has existing optical spectroscopy that provides a detection of Mg II, typically used for black hole mass estimation at z >~ 1. We carry out a spectral-line fitting procedure using both Hα and Mg II to determine the virial velocity of gas in the broad-line region, the continuum luminosity at 3000 Å, and the total Hα line luminosity. With a sample of 43 AGNs spanning a range of two decades in luminosity, we find a tight correlation between the ultraviolet and emission-line luminosity. There is also a close one-to-one relationship between the full width at half-maximum of Hα and Mg II. Both of these then lead to there being very good agreement between Hα- and Mg II-based masses over a wide range in black hole mass, i.e., M BH ~ 107-9 M ⊙. In general, these results demonstrate that local scaling relations, using Mg II or Hα, are applicable for AGNs at moderate luminosities and up to z ~ 2
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