2,446 research outputs found
FIRST J102347.6+003841: The First Radio-Selected Cataclysmic Variable
We have identified the 1.4 GHz radio source FIRST J102347.6+003841 (hereafter
FIRST J1023+0038) with a previously unknown 17th-mag Galactic cataclysmic
variable (CV). The optical spectrum resembles that of a magnetic (AM Herculis-
or DQ Herculis-type) CV. Five nights of optical CCD photometry showed
variations on timescales of minutes to hours, along with rapid flickering. A
re-examination of the FIRST radio survey data reveals that the radio detection
was based on a single 6.6 mJy flare; on two other occasions the source was
below the ~1 mJy survey limit. Several other magnetic CVs are known to be
variable radio sources, suggesting that FIRST J1023+0038 is a new member of
this class (and the first CV to be discovered on the basis of radio emission).
However, FIRST J1023+0038 is several optical magnitudes fainter than the other
radio-detected magnetic CVs. It remains unclear whether the source simply had a
very rare and extraordinarily intense radio flare at the time of the FIRST
observation, or is really an unusually radio-luminous CV; thus further
observations are urged.Comment: 4 pages, 3 figures; accepted for December 2002 issue of Publications
of the Astronomical Society of the Pacifi
Diversity of gut microflora is required for the generation of B cell with regulatory properties in a skin graft model
B cells have been reported to promote graft rejection through alloantibody production. However, there is growing evidence that B cells can contribute to the maintenance of tolerance. Here, we used a mouse model of MHC-class I mismatched skin transplantation to investigate the contribution of B cells to graft survival. We demonstrate that adoptive transfer of B cells prolongs skin graft survival but only when the B cells were isolated from mice housed in low sterility "conventional" (CV) facilities and not from mice housed in pathogen free facilities (SPF). However, prolongation of skin graft survival was lost when B cells were isolated from IL-10 deficient mice housed in CV facilities. The suppressive function of B cells isolated from mice housed in CV facilities correlated with an anti-inflammatory environment and with the presence of a different gut microflora compared to mice maintained in SPF facilities. Treatment of mice in the CV facility with antibiotics abrogated the regulatory capacity of B cells. Finally, we identified transitional B cells isolated from CV facilities as possessing the regulatory function. These findings demonstrate that B cells, and in particular transitional B cells, can promote prolongation of graft survival, a function dependent on licensing by gut microflora
Transcriptome Analysis of Alcohol Drinking in Non-Dependent and Dependent Mice Following Repeated Cycles of Forced Swim Stress Exposure
Chronic stress is a known contributing factor to the development of drug and alcohol addiction. Animal models have previously shown that repeated forced swim stress promotes escalated alcohol consumption in dependent animals. To investigate the underlying molecular adaptations associated with stress and chronic alcohol exposure, RNA-sequencing and bioinformatics analyses were conducted on the prefrontal cortex (CTX) of male C57BL/6J mice that were behaviorally tested for either non-dependent alcohol consumption (CTL), chronic intermittent ethanol (CIE) vapor dependent alcohol consumption, repeated bouts of forced swim stress alone (FSS), and chronic intermittent ethanol with forced swim stress (CIE + FSS). Brain tissue from each group was collected at 0-h, 72-h, and 168-h following the final test to determine long-lasting molecular changes associated with maladaptive behavior. Our results demonstrate unique temporal patterns and persistent changes in coordinately regulated gene expression systems with respect to the tested behavioral group. For example, increased expression of genes involved in âtransmitter-gated ion channel activityâ was only determined for CIE + FSS. Overall, our results provide a summary of transcriptomic adaptations across time within the CTX that are relevant to understanding the neurobiology of chronic alcohol exposure and stress
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The art of indigeneity: Aesthetics and competition in Mexican economies of culture
On the basis of ethnographic research with woodcarvers in Oaxaca, Mexico, this paper investigates the role that aesthetic practices play in economic competition in cultural markets. I explain how one family has become the most successful artisans in their village by aesthetically referencing the indigenous art that is highly sought after by the North American ethnic art market. By reformulating Bourdieu's analysis of artistic fields, I argue that aesthetic competition should be theorised at the level of genres, which allow insight into how individual aesthetic innovations may transform the fields in which art is produced and circulated. I show that by referencing indigeneity, this successful family not only accesses a new market but also renders their work more authoritative than the carvings of their neighbours, which aesthetically reference Mexican âartesanĂasâ (craftwork). In so doing, they not only earn more money but also change the ways that Oaxacan woodcarvings are valued in general
Clinical Manifestations and Case Management of Ebola Haemorrhagic Fever caused by a newly identified virus strain, Bundibugyo, Uganda, 2007-2008
A confirmed Ebola haemorrhagic fever (EHF) outbreak in Bundibugyo, Uganda, November 2007-February 2008, was caused by a putative new species (Bundibugyo ebolavirus). It included 93 putative cases, 56 laboratory-confirmed cases, and 37 deaths (CFRâ=â25%). Study objectives are to describe clinical manifestations and case management for 26 hospitalised laboratory-confirmed EHF patients. Clinical findings are congruous with previously reported EHF infections. The most frequently experienced symptoms were non-bloody diarrhoea (81%), severe headache (81%), and asthenia (77%). Seven patients reported or were observed with haemorrhagic symptoms, six of whom died. Ebola care remains difficult due to the resource-poor setting of outbreaks and the infection-control procedures required. However, quality data collection is essential to evaluate case definitions and therapeutic interventions, and needs improvement in future epidemics. Organizations usually involved in EHF case management have a particular responsibility in this respect
Characterizing the Cool KOIs. V. KOI-256: A Mutually Eclipsing Post-common Envelope Binary
We report that Kepler Object of Interest 256 (KOI-256) is a mutually eclipsing post-common envelope binary (ePCEB), consisting of a cool white dwarf (M_â
= 0.592 ± 0.089 M_â, R_â
= 0.01345 ± 0.00091 R_â, T_(eff) = 7100 ± 700 K) and an active M3 dwarf (M_â
= 0.51 ± 0.16 M_â, R_â
= 0.540 ± 0.014 R_â, T_(eff) = 3450 ± 50 K) with an orbital period of 1.37865 ± 0.00001 days. KOI-256 is listed as hosting a transiting planet-candidate by Borucki et al. and Batalha et al.; here we report that the planet-candidate transit signal is in fact the occultation of a white dwarf as it passes behind the M dwarf. We combine publicly-available long- and short-cadence Kepler light curves with ground-based measurements to robustly determine the system parameters. The occultation events are readily apparent in the Kepler light curve, as is spin-orbit synchronization of the M dwarf, and we detect the transit of the white dwarf in front of the M dwarf halfway between the occultation events. The size of the white dwarf with respect to the Einstein ring during transit (R_(Ein) = 0.00473 ± 0.00055 R â) causes the transit depth to be shallower than expected from pure geometry due to gravitational lensing. KOI-256 is an old, long-period ePCEB and serves as a benchmark object for studying the evolution of binary star systems as well as white dwarfs themselves, thanks largely to the availability of near-continuous, ultra-precise Kepler photometry
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Insiders, Outsiders, and the Struggle for Consecration in Cultural Fields: A Core-Periphery Perspective
Building on recent research emphasizing how legitimacy depends on consensus among audiences about candidatesâ characteristics and activities, we examine the relationship between cultural producersâ (candidates) position in the social structure and the consecration of their creative work by relevant audiences. We argue that the outcome of this process of evaluation in any cultural field, whether in art or science, is a function of (1) candidatesâ embeddedness within the field, and (2) the type of audienceâthat is, peers versus criticsâevaluating candidatesâ work. Specifically, we hypothesize that peers are more likely to favor candidates who are highly embedded in the field, whereas critics will not show such favoritism. We find support for these hypotheses in the context of the Hollywood motion picture industry
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Learning to teach data journalism: Innovation, influence and constraints
Journalism education has tended to respond slowly to developments in digital journalism, such as data journalism, despite or because of close links with the industry. This paper examines the obstacles to innovation in journalism education with particular reference to data journalism, drawing on the literature, a review of stakeholders and course documents, and the authorâs reflections on developing a data journalism module as part of a new MA programme. It highlights the complexities linked to the particular demands of data journalism, and identifies critical issues around student satisfaction; reputation and job/career outcomes; relevance, currency and appeal; programme management; and coherence. Rather than holding it back, more specialized socialization could assist journalism education to innovate effectively, the author suggests
The Sloan Digital Sky Survey-II Supernova Survey: Search Algorithm and Follow-up Observations
The Sloan Digital Sky Survey-II Supernova Survey has identified a large
number of new transient sources in a 300 sq. deg. region along the celestial
equator during its first two seasons of a three-season campaign. Multi-band
(ugriz) light curves were measured for most of the sources, which include solar
system objects, Galactic variable stars, active galactic nuclei, supernovae
(SNe), and other astronomical transients. The imaging survey is augmented by an
extensive spectroscopic follow-up program to identify SNe, measure their
redshifts, and study the physical conditions of the explosions and their
environment through spectroscopic diagnostics. During the survey, light curves
are rapidly evaluated to provide an initial photometric type of the SNe, and a
selected sample of sources are targeted for spectroscopic observations. In the
first two seasons, 476 sources were selected for spectroscopic observations, of
which 403 were identified as SNe. For the Type Ia SNe, the main driver for the
Survey, our photometric typing and targeting efficiency is 90%. Only 6% of the
photometric SN Ia candidates were spectroscopically classified as non-SN Ia
instead, and the remaining 4% resulted in low signal-to-noise, unclassified
spectra. This paper describes the search algorithm and the software, and the
real-time processing of the SDSS imaging data. We also present the details of
the supernova candidate selection procedures and strategies for follow-up
spectroscopic and imaging observations of the discovered sources.Comment: Accepted for publication in The Astronomical Journal (66 pages, 13
figures); typos correcte
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