4,124 research outputs found

    Bryophytes from the Republic of Equatorial Guinea (West-Central Africa) : 2., bryophytes collected by Emilio Guinea (1907-1985) in the Island of Bioco in 1947

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    Some unidentified samples of bryophytes collected by Emilio Guinea in Bioco (Equatorial Guinea) in 1947 have been studied. Twenty-seven taxa are the result of this study, nine of them being new for Equatorial Guinea and two new for the island of Bioco.Se han estudiado varias muestras de briófitos sin identificar recogidas por Emilio Guinea en Bioco (Guinea Ecuatorial) en 1947. Veintisiete taxones son el resultado de este estudio, siendo nueve de ellos novedad para Guinea Ecuatorial y dos más, nuevos para la isla de Bioco

    On the stability of some continuous systems subjected to random excitation

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    Conditions determined for sure stability of continuous systems subjected to random excitatio

    On the stability of a column subjected to a time-dependent axial load

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    Exponential bounds and stability conditions for linear elastic column subjected to time varying axial loa

    Centro de recuperação de animais selvagens de Castelo Branco - resultados 1999 a 2001.

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    O CERAS (Centro de Estudos e Recuperação de Animais Selvagens de Castelo Branco) está localizado na Escola Superior Agrária de Castelo Branco e tem como principais objectivos a recuperação e o estudo da fauna selvagem, através da recuperação, programas de reprodução em cativeiro, estudos para a protecção da fauna e dos seus habitats. Com este artigo pretendemos mostrar os primeiros resultados obtidos no centro de recuperação de fauna durante os 3 primeiros anos de funcionamento, 1999 a 2001, no qual deram entrada 157 animais, e destes 50% foram devolvidos à natureza. As principais causas de ingresso dos animais são a pilhagem/cativeiro ilegal, seguido de órfãos, atropelamentos e tiro. Existe uma variação anual na entrada de animais no centro que está relacionada com o final da época de nidificação e o começo da actividade cinegética.info:eu-repo/semantics/publishedVersio

    The Dwarf Galaxy Population of the Dorado group down to Mv=-11

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    We present V and I CCD photometry of suspected low-surface brightness dwarf galaxies detected in a survey covering ~2.4 deg^2 around the central region of the Dorado group of galaxies. The low-surface brightness galaxies were chosen based on their sizes and magnitudes at the limiting isophote of 26.0V\mu. The selected galaxies have magnitudes brighter than V=20 (Mv=-11 for an assumed distance to the group of 17.2 Mpc), with central surface brightnesses \mu0>22.5 V mag/arcsec^2, scale lengths h>2'', and diameters > 14'' at the limiting isophote. Using these criteria, we identified 69 dwarf galaxy candidates. Four of them are large very low-surface brightness galaxies that were detected on a smoothed image, after masking high surface brightness objects. Monte Carlo simulations performed to estimate completeness, photometric uncertainties and to evaluate our ability to detect extended low-surface brightness galaxies show that the completeness fraction is, on average, > 80% for dwarf galaxies with 17<MV<10.5-17<M_{V}<-10.5 and 22.5<\mu0<25.5 V mag/arcsec^2, for the range of sizes considered by us (D>14''). The V-I colors of the dwarf candidates vary from -0.3 to 2.3 with a peak on V-I=0.98, suggesting a range of different stellar populations in these galaxies. The projected surface density of the dwarf galaxies shows a concentration towards the group center similar in extent to that found around five X-ray groups and the elliptical galaxy NGC1132 studied by Mulchaey and Zabludoff (1999), suggesting that the dwarf galaxies in Dorado are probably physically associated with the overall potential well of the group.Comment: 32 pages, 16 postscript figures and 3 figures in GIF format, aastex v5.0. To appear in The Astronomical Journal, January 200

    Discovery of a Galaxy Cluster in the Foreground of the Wide-Separation Quasar Pair UM425

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    We report the discovery of a cluster of galaxies in the field of UM425, a pair of quasars separated by 6.5arcsec. Based on this finding, we revisit the long-standing question of whether this quasar pair is a binary quasar or a wide-separation lens. Previous work has shown that both quasars are at z=1.465 and show broad absorption lines. No evidence for a lensing galaxy has been found between the quasars, but there were two hints of a foreground cluster: diffuse X-ray emission observed with Chandra, and an excess of faint galaxies observed with the Hubble Space Telescope. Here we show, via VLT spectroscopy, that there is a spike in the redshift histogram of galaxies at z=0.77. We estimate the chance of finding a random velocity structure of such significance to be about 5%, and thereby interpret the diffuse X-ray emission as originating from z=0.77, rather than the quasar redshift. The mass of the cluster, as estimated from either the velocity dispersion of the z=0.77 galaxies or the X-ray luminosity of the diffuse emission, would be consistent with the theoretical mass required for gravitational lensing. The positional offset between the X-ray centroid and the expected location of the mass centroid is about 40kpc, which is not too different from offsets observed in lower redshift clusters. However, UM425 would be an unusual gravitational lens, by virtue of the absence of a bright primary lensing galaxy. Unless the mass-to-light ratio of the galaxy is at least 80 times larger than usual, the lensing hypothesis requires that the galaxy group or cluster plays a uniquely important role in producing the observed deflections. Based on observations performed with the Very Large Telescope at the European Southern Observatory, Paranal, Chile.Comment: 12 pages, accepted by ApJ 2005, May 1

    In vivo testing of safety and immunogenicity of new vaccine candidates against PCV2 designed for a better performance than that showed by currently marketed vaccines

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    Porcine circovirus type 2 (PCV2) is a globally distributed virus causing considerable economic losses. It affects mainly piglets after the weaning, leading to the disease known as postweaning multisystemic wasting syndrome, whose consequences are death or a significant reduction of pigs fattening rate. PCV2 also affects pregnant sows, leading to abortions. There are four commercial vaccines against PCV2, two killed vaccines and two recombinant vaccines. All of them are based on PCV2 strains of genotype a, which was predominant in the field when the vaccines were marketed. Since live replicative virus could not be used as vaccines, these vaccines lead to prevention of symptoms but not to complete viral clearance. Vaccinated and infected pigs can still infect other pigs. Today the predominant genotypes are PCV2 b and d. Although the marketed vaccines showed cross-protection against heterologous genotypes, it is suboptimal and there are increasing cases of vaccine escape by new PCV2 strains. ADL Bionatur Solutions designed and produced three new generation recombinant vaccine candidates, BNT029, 030, and 031 with two goals: improve antigenic presentation to achieve better viral clearance and to raise specific immunity against the new genotypes. In this project, the vaccine candidates have been tested in vivo for safety and immunogenicity in comparison with the current commercial leader, Ingelvac CircoFLEX® from Boehringer Ingelheim. In mice, the new candidates raised cell-mediated immunity of higher intensity than that raised by the commercial gold standard, and with a more significant Th1-specific component biased to the PCV2b and PCV2d genotypes. In an experimental trial in piglets, immunization with BNT029, 030, and 031 did not lead to any adverse effect. The three new candidates led to seroconversion, with antibody titers significantly higher than those raised by the commercial gold standard. While the antisera raised in piglets by Ingelvac CircoFLEX predominantly recognized viral antigens derived from a PCV2a strain, the antisera raised by BNT029, 030, and 031 predominantly recognized viral antigens derived from PCV2b and PCV2d strains. Therefore, we have confirmed the initial hypotheses aimed for the new candidates. Currently, we are carrying out serum neutralization assays to confirm that the immune response raised by the new candidates in piglets can neutralize effectively the infection by the currently predominant viral strains of PCV2
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