3,362 research outputs found

    The Potential Role of Local Ethical Committees in the Moderation of Experiments on Animals in Britain

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    Scientists working with laboratory animals in Britain are made aware forcibly that a severe ethical dilemma surrounds using animals in experiments. Certain vociferous sections of the community press the issue on the general public\u27s attention, and media sources tend to propagate views expressed by the most extreme parties while neglecting coverage of mature, rational opinions. It is, perhaps, no bad thing for the scientific community to be frequently reminded to take a responsible attitude to the use of animals. Still, recent overt, even illegal, activity on the part of extremist animal protectionist groups has encouraged a regrettable polarization of viewpoints, with some scientific institutions seeking to withdraw still further from public scrutiny and accountability

    Radio sources in the Chandra Galactic Bulge Survey

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    We discuss radio sources in the Chandra Galactic Bulge Survey region. By cross-matching the X-ray sources in this field with the NRAO VLA Sky Survey archival data, we find 12 candidate matches. We present a classification scheme for radio/X-ray matches in surveys taken in or near the Galactic plane, taking into account other multiwavelength data. We show that none of the matches found here is likely to be due to coronal activity from normal stars because the radio to X-ray flux ratios are systematically too high. We show that one of the source could be a radio pulsar, and that one could be a planetary nebula, but that the bulk of the sources are likely to be background active galactic nuclei (AGN), with many confirmed through a variety of approaches. Several of the AGN are bright enough in the near-infrared (and presumably in the optical) to use as probes of the interstellar medium in the inner Galaxy

    Lymphotoxins and cytomegalovirus cooperatively induce interferon-beta, establishing host-virus détente

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    Tumor necrosis factor (TNF)-related cytokines regulate cell death and survival and provide strong selective pressures for viruses, such as cytomegalovirus (CMV), to evolve counterstrategies in order to persist in immune-competent hosts. Signaling by the lymphotoxin (LT)-β receptor or TNF receptor-1, but not Fas or TRAIL receptors, inhibits the cytopathicity and replication of human CMV by a nonapoptotic, reversible process that requires nuclear factor κB (NF-κB)-dependent induction of interferon-β (IFN-β). Efficient induction of IFN-β requires virus infection and LT signaling, demonstrating the need for both host and viral factors in the curtailment of viral replication without cellular elimination. LTα-deficient mice and LTβR-Fc transgenic mice were profoundly susceptible to murine CMV infection. Together, these results reveal an essential and conserved role for LTs in establishing host defense to CMV

    Measurements of fuselage skin strains and displacements near a longitudinal lap joint in a pressurized aircraft

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    Strains and displacements in a small area near a longitudinal lap joint in the fuselage skin of a B737 aircraft were measured during a pressurization cycle to a differential pressure of 6.2 psi while the aircraft was on the ground. It was found that hoop strains were higher than longitudinal strains at each location; membrane strains in the unreinforced skin were higher than in the joint; membrane strains in the hoop direction, as well as radial displacements, tended to be highest at the mid-bay location between skin reinforcements; significant bending in the hoop direction occurred in the joint and in the skin near the joint, and the bending was unsymmetrically distributed about the stringer at the middle of the joint; and radial displacements were unsymmetrically distributed across the lap joint. The interpretation of the strain gage data for locations on the bonded and riveted lap joint assumed that the joint did not contain disbonded areas

    The Cross-correlation of MgII Absorption and Galaxies in BOSS

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    We present a measurement of the cross-correlation of MgII absorption and massive galaxies, using the DR11 main galaxy sample of the Baryon Oscillation Spectroscopic Survey of SDSS-III (CMASS galaxies), and the DR7 quasar spectra of SDSS-II. The cross-correlation is measured by stacking quasar absorption spectra shifted to the redshift of galaxies that are within a certain impact parameter bin of the quasar, after dividing by a quasar continuum model. This results in an average MgII equivalent width as a function of impact parameter from a galaxy, ranging from 50 kpc to more than 10 Mpc in proper units, which includes all MgII absorbers. We show that special care needs to be taken to use an unbiased quasar continuum estimator, to avoid systematic errors in the measurement of the mean stacked MgII equivalent width. The measured cross-correlation follows the expected shape of the galaxy correlation function, although measurement errors are large. We use the cross-correlation amplitude to derive the bias factor of MgII absorbers, finding bMgII = 2.33 \pm? 0.19, where the error accounts only for the statistical uncertainty in measuring the mean equivalent width. This bias factor is larger than that obtained in previous studies and may be affected by modeling uncertainties that we discuss, but if correct it suggests that MgII absorbers at redshift z \simeq 0:5 are spatially distributed on large scales similarly to the CMASS galaxies in BOSS. Keywords: galaxies: haloes, galaxies: formation, quasars: absorption lines, large-scale structure of universeComment: Accepted for publication to MNRAS. Accepted 2014 December 12. Received 2014 November 29; in original form 2014 February

    Magellan LDSS3 emission confirmation of galaxies hosting metal-rich Lyman-alpha absorption systems

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    Using the Low Dispersion Survey Spectrograph 3 at the Magellan II Clay Telescope, we target {candidate absorption host galaxies} detected in deep optical imaging {(reaching limiting apparent magnitudes of 23.0-26.5 in g,r,i,g, r, i, and zz filters) in the fields of three QSOs, each of which shows the presence of high metallicity, high NHIN_{\rm HI} absorption systems in their spectra (Q0826-2230: zabsz_{abs}=0.9110, Q1323-0021: zabs=0.7160z_{abs}=0.7160, Q1436-0051: zabs=0.7377,0.9281z_{abs}=0.7377, 0.9281). We confirm three host galaxies {at redshifts 0.7387, 0.7401, and 0.9286} for two of the Lyman-α\alpha absorption systems (one with two galaxies interacting). For these systems, we are able to determine the star formation rates (SFRs); impact parameters (from previous imaging detections); the velocity shift between the absorption and emission redshifts; and, for one system, also the emission metallicity.} Based on previous photometry, we find these galaxies have L>>L^{\ast}. The [O II] SFRs for these galaxies are in the range 112511-25 M_{\odot} yr1^{-1} {(uncorrected for dust)}, while the impact parameters lie in the range 355435-54 kpc. {Despite the fact that we have confirmed galaxies at 50 kpc from the QSO, no gradient in metallicity is indicated between the absorption metallicity along the QSO line of sight and the emission line metallicity in the galaxies.} We confirm the anti-correlation between impact parameter and NHIN_{\rm HI} from the literature. We also report the emission redshift of five other galaxies: three at zem>zQSOz_{em}>z_{QSO}, and two (L<<L^{\ast}) at zem<zQSOz_{em}<z_{QSO} not corresponding to any known absorption systems.Comment: 14 pages, 7 figures, 4 tables, accepted to MNRA

    Mass and density of B-type asteroid (702) Alauda

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    Observations with the adaptive optics system on the Very Large Telescope reveal that outer main belt asteroid (702) Alauda has a small satellite with primary to secondary diameter ratio of \sim56. The secondary revolves around the primary in 4.9143 ±\pm 0.007 days at a distance of 1227 ±\pm 24 km, yielding a total system mass of (6.057 ±\pm 0.36) ×\times 1018^{18} kg. Combined with an IRAS size measurement, our data yield a bulk density for this B-type asteroid of 1570 ±\pm 500 kg~m3^{-3}.Comment: In press, ApJ 2011. 6 pages, 4 figure

    General health and residential proximity to the coast in Belgium : results from a cross-sectional health survey

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    The health risks of coastal areas have long been researched, but the potential benefits for health are only recently being explored. The present study compared the general health of Belgian citizens a) according to the EU's definition of coastal ( 50 km), and b) between eight more refined categories of residential proximity to the coast ( 250 km). Data was drawn from the Belgian Health Interview Survey (n = 60,939) and investigated using linear regression models and mediation analyses on several hypothesized mechanisms. Results indicated that populations living 50-100 km. Four commonly hypothesized mechanisms were considered but no indirect associations were found: scores for mental health, physical activity levels and social contacts were not higher at 0-5 km from the coast, and air pollution (PM ic , concentrations) was lower at 0-5 km from the coast but not statistically associated with better health. Results are controlled for typical variables such as age, sex, income, neighbourhood levels of green and freshwater blue space, etc. The spatial urban-rural-nature mosaic at the Belgian coast and alternative explanations are discussed. The positive associations between the ocean and human health observed in this study encourage policy makers to manage coastal areas sustainably to maintain associated public health benefits into the future

    The Relationship Between X-ray Luminosity and Duty Cycle for Dwarf Novae and their Specific Frequency in the Inner Galaxy

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    We measure the duty cycles for an existing sample of well observed, nearby dwarf novae using data from AAVSO, and present a quantitative empirical relation between the duty cycle of dwarf novae outbursts and the X-ray luminosity of the system in quiescence. We have found that logDC=0.63(±0.21)×(logLX(ergs1)31.3)0.95(±0.1)\log DC=0.63(\pm0.21)\times(\log L_{X}({\rm erg\,s^{-1}})-31.3)-0.95(\pm0.1), where DC stands for duty cycle. We note that there is intrinsic scatter in this relation greater than what is expected from purely statistical errors. Using the dwarf nova X-ray luminosity functions from \citet{Pretorius12} and \citet{Byckling10}, we compare this relation to the number of dwarf novae in the Galactic Bulge Survey which were identified through optical outbursts during an 8-day long monitoring campaign. We find a specific frequency of X-ray bright (LX>1031ergs1L_{X}>10^{31}\,{\rm erg\,s^{-1}}) Cataclysmic Variables undergoing Dwarf Novae outbursts in the direction of the Galactic Bulge of 6.6±4.7×105M16.6\pm4.7\times10^{-5}\,M_{\odot}^{-1}. Such a specific frequency would give a Solar neighborhood space density of long period CVs of ρ=5.6±3.9×106\rho=5.6\pm3.9\times10^{-6}\,pc3^{-3}. We advocate the use of specific frequency in future work, given that projects like LSST will detect DNe well outside the distance range over which ρconst\rho\approx{\textrm const}.Comment: 9 pagers, 4 figures Accepted for publication in MNRA
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