14,933 research outputs found
VisGenome: visualization of single and comparative genome representations
VisGenome visualizes single and comparative representations for the rat, the mouse and the human chromosomes at different levels of detail. The tool offers smooth zooming and panning which is more flexible than seen in other browsers. It presents information available in Ensembl for single chromosomes, as well as homologies (orthologue predictions including ortholog one2one, apparent ortholog one2one, ortholog many2many) for any two chromosomes from different species. The application can query supporting data from Ensembl by invoking a link in a browser
SXP 323 - an unusual X-ray binary system in the Small Magellanic Cloud
Spectroscopic observations taken with the VLT/UVES telescope/instrument are
presented of the unusual Small Magellanic Cloud (SMC) X-ray binary system SXP
323 = AX J0051-733. This system shows a clear modulation at 0.71d in long term
optical photometry which has been proposed as the binary period of this system.
The high resolution optical spectra, taken at a range of phases during the
0.71d cycle, rule out this possibility. Instead it is suggested that this
long-term effect is due to Non Radial Pulsations (NRP) in the Be star companion
to SXP 323. In addition, the spectra show clear evidence for major changes in
the (V/R) ratio of the double peaks of the Balmer lines indicative of
asymmetries in the circumstellar disk. The complex structure of the
interstellar lines are also discussed in the context of the SMC structure.Comment: Accepted in MNRA
Cyclic Ovarian Hormone Modulation of Supraspinal Î\u3csup\u3e9\u3c/sup\u3e-tetrahydrocannabinol-induced Antinociception and Cannabinoid Receptor Binding in the Female Rat
Estrous cycle-related fluctuations in delta-9-tetrahydrocannabinol (THC)-induced antinociception have been observed in the rat. The aim of this study was to determine which major ovarian hormone modulates the antinociceptive effects of i.c.v. THC, and whether hormone modulation of THC\u27s behavioral effects could be due to changes in brain cannabinoid receptors (CBr). Vehicle (oil) or hormones (estradiol or progesterone, or both) were administered to female rats on days 3 and 7 post-ovariectomy. On the morning or afternoon of day 8 or day 9, vehicle or THC (100 ÎŒg) was administered i.c.v. Paw pressure, tail withdrawal, locomotor activity and catalepsy tests were conducted over a 3-h period. Estradiol (with and without progesterone) enhanced THC-induced paw pressure antinociception only. Ovarian hormones time-dependently modulated CBr in brain structures that mediate antinociception and locomotor activity, but the changes observed in CBr did not parallel changes in behavior. However, the time course of CBr changes must be further elucidated to determine the functional relationship between receptor changes and antinociceptive sensitivity to THC
Dosage compensation in birds
AbstractThe Z and W sex chromosomes of birds have evolved independently from the mammalian X and Y chromosomes [1]. Unlike mammals, female birds are heterogametic (ZW), while males are homogametic (ZZ). Therefore male birds, like female mammals, carry a double dose of sex-linked genes relative to the other sex. Other animals with nonhomologous sex chromosomes possess âdosage compensationâ systems to equalize the expression of sex-linked genes. Dosage compensation occurs in animals as diverse as mammals, insects, and nematodes, although the mechanisms involved differ profoundly [2]. In birds, however, it is widely accepted that dosage compensation does not occur [3â5], and the differential expression of Z-linked genes has been suggested to underlie the avian sex-determination mechanism [6]. Here we show equivalent expression of at least six of nine Z chromosome genes in male and female chick embryos by using real-time quantitative PCR [7]. Only the Z-linked ScII gene, whose ortholog in Caenorhabditis elegans plays a crucial role in dosage compensation [8], escapes compensation by this assay. Our results imply that the majority of Z-linked genes in the chicken are dosage compensated
Decreasing Opportunities for Low-Wage Workers: The Role of the Nondiscrimination Law for Employer-Provided Health Insurance
As of 1978, the favorable tax treatment of fringe benefits, including health insurance, has been regulated via a nondiscrimination clause such that low-wage, full-time workers must be offered health insurance (and other benefits) that are offered to higher-wage workers by the firm. Part-time workers may be excluded from coverage, however, creating incentives for firms to hire some types of workers part time to deny them coverage. We hypothesize that firms will hire fewer workers whose relative costs have increased, that is, low-wage workers. These workers will be less likely to work for firms that offer coverage, and those that do will be more likely to work part time without being eligible for the firmâs health insurance benefits. We use the 1988 and 1993 Employee Benefits Supplements to the Current Population Surveys and an employer premium imputation to examine these hypotheses. Both the descriptive and multivariate analysis are consistent with our hypotheses. We predict the probability of working for a firm that offers health insurance to decrease as premiums increase for both high- and low-wage workers. An increase in the premium is also associated with a decrease in the probability of part-time work, but an even greater decrease in the joint probability of part-time work with eligibility for health insurance.
Community experiences of organised crime in Scotland
The research explored community experiences of serious organised crime in Scotland (SOC). The report provides information on the nature and extent of the impact of SOC on everyday life in the community, as well as offering suggestions for policy development. The study sought to answer the following questions: 1)What are the relationships that exist between SOC and communities in Scotland? 2)What are the experiences and perceptions of residents, stakeholders and organisations of the scope and nature of SOC within their local area? and 3)How does SOC impact on community wellbeing, and to what extent can the harms associated with SOC be mitigated
A 0535+26: Back in business
In May/June 2005, after 10 years of inactivity, the Be/X-ray binary system A
0535+26 underwent a major X-ray outburst. In this paper data are presented from
10 years of optical, IR and X-ray monitoring showing the behaviour of the
system during the quiescent epoch and the lead up to the new outburst. The
results show the system going through a period when the Be star in the system
had a minimal circumstellar disk and then a dramatic disk recovery leading,
presumably, to the latest flare up of X-ray emission. The data are interpreted
in terms of the state of the disk and its interaction with the neutron star
companion.Comment: Accepted for publication in MNRA
GEO debris and interplanetary dust: fluxes and charging behavior
In September 1996, a dust/debris detector: GORID was launched into the
geostationary (GEO) region as a piggyback instrument on the Russian Express-2
telecommunications spacecraft. The instrument began its normal operation in
April 1997 and ended its mission in July 2002. The goal of this work was to use
GORID's particle data to identify and separate the space debris to
interplanetary dust particles (IDPs) in GEO, to more finely determine the
instrument's measurement characteristics and to derive impact fluxes. While the
physical characteristics of the GORID impacts alone are insufficient for a
reliable distinction between debris and interplanetary dust, the temporal
behavior of the impacts are strong enough indicators to separate the
populations based on clustering. Non-cluster events are predominantly
interplanetary, while cluster events are debris. The GORID mean flux
distributions (at mass thresholds which are impact speed dependent) for IDPs,
corrected for dead time, are 1.35x10^{-4} m^{-2} s^{-1} using a mean detection
rate: 0.54 d^{-1}, and for space debris are 6.1x10^{-4} m^{-2} s^{-1} using a
mean detection rate: 2.5 d^{-1}. Beta-meteoroids were not detected. Clusters
could be a closely-packed debris cloud or a particle breaking up due to
electrostatic fragmentation after high charging.Comment: * Comments: 6 pages, 4 postscript figures, in Dust in Planetary
Systems 2005, Krueger, H. and Graps, A. eds., ESA Publications, SP in press
(2006). For high resolution version, see:
http://www.mpi-hd.mpg.de/dustgroup/~graps/dips2005/GrapsetalDIPS2005.pd
NGC 3105: a young open cluster with low metallicity
NGC 3105 is a young open cluster hosting blue, yellow and red supergiants.
This rare combination makes it an excellent laboratory to constrain
evolutionary models of high-mass stars. It is poorly studied and fundamental
parameters such as its age or distance are not well defined. We intend to
characterize in an accurate way the cluster as well as its evolved stars, for
which we derive for the first time atmospheric parameters and chemical
abundances. We identify 126 B-type likely members within a radius of
2.70.6 arcmin, which implies an initial mass, 4100
M. We find a distance of 7.20.7 kpc for NGC 3105, placing it at
=10.01.2 kpc. Isochrone fitting supports an age of 286 Ma,
implying masses around 9.5 M for the supergiants. A high fraction of
Be stars (25 %) is found at the top of the main sequence down to
spectral type b3. From the spectral analysis we estimate for the cluster a
=+46.90.9 km s and a low metallicity,
[Fe/H]=-0.290.22. We also have determined, for the first time, chemical
abundances for Li, O, Na, Mg, Si, Ca, Ti, Ni, Rb, Y, and Ba for the evolved
stars. The chemical composition of the cluster is consistent with that of the
Galactic thin disc. An overabundance of Ba is found, supporting the enhanced
-process. NGC 3105 has a low metallicity for its Galactocentric distance,
comparable to typical LMC stars. It is a valuable spiral tracer in a very
distant region of the Carina-Sagittarius spiral arm, a poorly known part of the
Galaxy. As one of the few Galactic clusters containing blue, yellow and red
supergiants, it is massive enough to serve as a testbed for theoretical
evolutionary models close to the boundary between intermediate and high-mass
stars.Comment: 18 pages, 13 figures. Accepted for publication in A&
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