3,362 research outputs found
The Potential Role of Local Ethical Committees in the Moderation of Experiments on Animals in Britain
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
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
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
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
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
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 and filters) in the fields of three QSOs, each of which shows the
presence of high metallicity, high absorption systems in their
spectra (Q0826-2230: =0.9110, Q1323-0021: ,
Q1436-0051: ). We confirm three host galaxies {at
redshifts 0.7387, 0.7401, and 0.9286} for two of the Lyman- 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 LL. The [O II]
SFRs for these galaxies are in the range M yr
{(uncorrected for dust)}, while the impact parameters lie in the range
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 from
the literature. We also report the emission redshift of five other galaxies:
three at , and two (LL) at 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
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 56. The secondary revolves around
the primary in 4.9143 0.007 days at a distance of 1227 24 km,
yielding a total system mass of (6.057 0.36) 10 kg.
Combined with an IRAS size measurement, our data yield a bulk density for this
B-type asteroid of 1570 500 kg~m.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
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
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 , 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 () Cataclysmic Variables undergoing
Dwarf Novae outbursts in the direction of the Galactic Bulge of
. Such a specific frequency would give
a Solar neighborhood space density of long period CVs of
pc. 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 .Comment: 9 pagers, 4 figures Accepted for publication in MNRA
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