491 research outputs found
The Void Galaxy Survey
The Void Galaxy Survey (VGS) is a multi-wavelength program to study 60
void galaxies. Each has been selected from the deepest interior regions of
identified voids in the SDSS redshift survey on the basis of a unique geometric
technique, with no a prior selection of intrinsic properties of the void
galaxies. The project intends to study in detail the gas content, star
formation history and stellar content, as well as kinematics and dynamics of
void galaxies and their companions in a broad sample of void environments. It
involves the HI imaging of the gas distribution in each of the VGS galaxies.
Amongst its most tantalizing findings is the possible evidence for cold gas
accretion in some of the most interesting objects, amongst which are a polar
ring galaxy and a filamentary configuration of void galaxies. Here we shortly
describe the scope of the VGS and the results of the full analysis of the pilot
sample of 15 void galaxies.Comment: 9 pages, 6 figures. This is an extended version of a paper to appear
in "Environment and the Formation of Galaxies: 30 years later", Proceedings
of Symposium 2 of JENAM 2010, eds. I. Ferreras, A. Pasquali, ASSP, Springer.
Version with highres figures at
http://www.astro.rug.nl/~weygaert/vgs_jenam_weygaert.col.pd
Acute myopathy secondary to oral steroid therapy in a 49-year-old man: a case report
<p>Abstract</p> <p>Introduction</p> <p>Acute myopathy caused by oral corticosteroids is rare. We present a case of myopathy occurring after two doses of methylprednisolone. Typically, acute steroid myopathy occurs with therapy using intravenous corticosteroids at high doses. Acute myopathy developing very early in the course of treatment with oral corticosteroids has been reported only once in the literature. Corticosteroid therapy may be complicated by myopathy, usually chronic, after prolonged high-dose therapy. Acute myopathy caused by exogenous corticosteroids is rare, usually with intravenous corticosteroids at high doses.</p> <p>Case presentation</p> <p>A 49-year-old Caucasian man developed acute myopathy after taking oral methylprednisolone for only two days, 24 mg on day 1 and 20 mg on day 2. He discontinued the medication because of new-onset myalgias and lethargy on day 3 and was seen in our clinic four days after beginning therapy. He completely recovered in four weeks by discontinuing the corticosteroids.</p> <p>Conclusion</p> <p>Among the many complications of corticosteroid therapy, acute myopathy is very rare. It requires prompt recognition and adjustment of therapy.</p
Circulating microRNAs Reveal Time Course of Organ Injury in a Porcine Model of Acetaminophen-Induced Acute Liver Failure
Acute liver failure is a rare but catastrophic condition which can progress rapidly to multi-organ failure. Studies investigating the onset of individual organ injury such as the liver, kidneys and brain during the evolution of acute liver failure, are lacking. MicroRNAs are short, non-coding strands of RNA that are released into the circulation following tissue injury. In this study, we have characterised the release of both global microRNA and specific microRNA species into the plasma using a porcine model of acetaminophen-induced acute liver failure. Pigs were induced to acute liver failure with oral acetaminophen over 19h±2h and death occurred 13h±3h thereafter. Global microRNA concentrations increased 4h prior to acute liver failure in plasma (P<0.0001) but not in isolated exosomes, and were associated with increasing plasma levels of the damage-associated molecular pattern molecule, genomic DNA (P<0.0001). MiR122 increased around the time of onset of acute liver failure (P<0.0001) and was associated with increasing international normalised ratio (P<0.0001). MiR192 increased 8h after acute liver failure (P<0.0001) and was associated with increasing creatinine (P<0.0001). The increase in miR124-1 occurred concurrent with the pre-terminal increase in intracranial pressure (P<0.0001) and was associated with decreasing cerebral perfusion pressure (P<0.002)
Cold gas accretion in galaxies
Evidence for the accretion of cold gas in galaxies has been rapidly
accumulating in the past years. HI observations of galaxies and their
environment have brought to light new facts and phenomena which are evidence of
ongoing or recent accretion:
1) A large number of galaxies are accompanied by gas-rich dwarfs or are
surrounded by HI cloud complexes, tails and filaments. It may be regarded as
direct evidence of cold gas accretion in the local universe. It is probably the
same kind of phenomenon of material infall as the stellar streams observed in
the halos of our galaxy and M31. 2) Considerable amounts of extra-planar HI
have been found in nearby spiral galaxies. While a large fraction of this gas
is produced by galactic fountains, it is likely that a part of it is of
extragalactic origin. 3) Spirals are known to have extended and warped outer
layers of HI. It is not clear how these have formed, and how and for how long
the warps can be sustained. Gas infall has been proposed as the origin. 4) The
majority of galactic disks are lopsided in their morphology as well as in their
kinematics. Also here recent accretion has been advocated as a possible cause.
In our view, accretion takes place both through the arrival and merging of
gas-rich satellites and through gas infall from the intergalactic medium (IGM).
The infall may have observable effects on the disk such as bursts of star
formation and lopsidedness. We infer a mean ``visible'' accretion rate of cold
gas in galaxies of at least 0.2 Msol/yr. In order to reach the accretion rates
needed to sustain the observed star formation (~1 Msol/yr), additional infall
of large amounts of gas from the IGM seems to be required.Comment: To appear in Astronomy & Astrophysics Reviews. 34 pages.
Full-resolution version available at
http://www.astron.nl/~oosterlo/accretionRevie
A review of elliptical and disc galaxy structure, and modern scaling laws
A century ago, in 1911 and 1913, Plummer and then Reynolds introduced their
models to describe the radial distribution of stars in `nebulae'. This article
reviews the progress since then, providing both an historical perspective and a
contemporary review of the stellar structure of bulges, discs and elliptical
galaxies. The quantification of galaxy nuclei, such as central mass deficits
and excess nuclear light, plus the structure of dark matter halos and cD galaxy
envelopes, are discussed. Issues pertaining to spiral galaxies including dust,
bulge-to-disc ratios, bulgeless galaxies, bars and the identification of
pseudobulges are also reviewed. An array of modern scaling relations involving
sizes, luminosities, surface brightnesses and stellar concentrations are
presented, many of which are shown to be curved. These 'redshift zero'
relations not only quantify the behavior and nature of galaxies in the Universe
today, but are the modern benchmark for evolutionary studies of galaxies,
whether based on observations, N-body-simulations or semi-analytical modelling.
For example, it is shown that some of the recently discovered compact
elliptical galaxies at 1.5 < z < 2.5 may be the bulges of modern disc galaxies.Comment: Condensed version (due to Contract) of an invited review article to
appear in "Planets, Stars and Stellar
Systems"(www.springer.com/astronomy/book/978-90-481-8818-5). 500+ references
incl. many somewhat forgotten, pioneer papers. Original submission to
Springer: 07-June-201
A retrospective study on the use of post-operative colonoscopy following potentially curative surgery for colorectal cancer in a Canadian province
BACKGROUND: Surveillance colonoscopy is commonly recommended following potentially curative surgery for colorectal cancer. We determined factors associated with patients undergoing a least one colonoscopy within five years of surgery. METHODS: In this historical cohort study, data on 3918 patients age 30 years or older residing in Alberta, Canada, who had undergone a potentially curative surgical resection for local or regional stage colorectal cancer between 1983 and 1995 were obtained from the provincial cancer registry, ministry of health and cancer clinic charts. Kaplan-Meier estimates of the probability of undergoing a post-operative colonoscopy were calculated for patient, tumor and treatment-related variables of interest. RESULTS: A colonoscopy was performed within five years of surgery in 1979 patients. The probability of undergoing a colonoscopy for those diagnosed in the 1990s was greater than for those diagnosed earlier (0.65 vs 0.55, P < 0.0001). The majority of the difference was seen at one-year following surgery, consistent with changes in surveillance practices. Those most likely to undergo a colonoscopy were those under age 70 (0.74 vs 0.50 for those age 70 – 79, P < 0.0001), who underwent a pre-operative colonoscopy (0.69 vs 0.54, P < 0.0001), and who underwent a resection with reanastomosis (0.62 vs 0.47 for abdominoperineal resection, P < 0.0001) by a surgeon who performs colonoscopies (0.68 vs 0.54, P < 0.0001). CONCLUSIONS: The majority of patients undergo colonoscopy following colorectal cancer surgery. However, there are important variations in surveillance practices across different patient and treatment characteristics
The Evolution of Compact Binary Star Systems
We review the formation and evolution of compact binary stars consisting of
white dwarfs (WDs), neutron stars (NSs), and black holes (BHs). Binary NSs and
BHs are thought to be the primary astrophysical sources of gravitational waves
(GWs) within the frequency band of ground-based detectors, while compact
binaries of WDs are important sources of GWs at lower frequencies to be covered
by space interferometers (LISA). Major uncertainties in the current
understanding of properties of NSs and BHs most relevant to the GW studies are
discussed, including the treatment of the natal kicks which compact stellar
remnants acquire during the core collapse of massive stars and the common
envelope phase of binary evolution. We discuss the coalescence rates of binary
NSs and BHs and prospects for their detections, the formation and evolution of
binary WDs and their observational manifestations. Special attention is given
to AM CVn-stars -- compact binaries in which the Roche lobe is filled by
another WD or a low-mass partially degenerate helium-star, as these stars are
thought to be the best LISA verification binary GW sources.Comment: 105 pages, 18 figure
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