318 research outputs found
Crossover of the weighted mean fragment mass scaling in 2D brittle fragmentation
We performed vertical and horizontal sandwich 2D brittle fragmentation
experiments. The weighted mean fragment mass was scaled using the multiplicity
. The scaling exponent crossed over at . In the
small regime, the binomial multiplicative (BM) model was
suitable and the fragment mass distribution obeyed log-normal form. However, in
the large regime, in which a clear power-law cumulative
fragment mass distribution was observed, it was impossible to describe the
scaling exponent using the BM model. We also found that the scaling exponent of
the cumulative fragment mass distribution depended on the manner of impact
(loading conditions): it was 0.5 in the vertical sandwich experiment, and
approximately 1.0 in the horizontal sandwich experiment.Comment: 5 pages, 3 figure
Brane-World and Holography
We consider the brane-world in the holographic point of view. Bearing the
realistic models in mind, the bulk massless scalar field is introduced. First
of all, we find the constraint on the coupling of the scalar fields with the
matter(not holographic CFT) on the brane. We show that the traceless part of
the energy-momentum tensor of holographic CFT is a part of the bulk Weyl
tensor. The trace part which comes from the trace-anomaly is corresponding to
the -term appeared in the generalized FRW equation in the brane-world.Comment: 4 pages, minor change
Scrutinizing LSP Dark Matter at the LHC
We show that LHC experiments might well be able to determine all the
parameters required for a prediction of the present density of thermal LSP
relics from the Big Bang era. If the LSP is an almost pure bino we usually only
need to determine its mass and the mass of the SU(2) singlet sleptons. This
information can be obtained by reconstructing the cascade . The only requirement is that ,
which is true for most of the cosmologically interesting parameter space. If
the LSP has a significant higgsino component, its predicted thermal relic
density is smaller than for an equal--mass bino. We show that in this case
squark decays also produce significant numbers of and
. Reconstructing the corresponding decay cascades then
allows to determine the higgsino component of the LSP
On the origin of anomalous velocity clouds in the Milky Way
We report that neutral hydrogen (HI) gas clouds, resembling High Velocity
Clouds (HVCs) observed in the Milky Way (MW), appear in MW-sized disk galaxies
formed in high-resolution Lambda Cold Dark Matter (LCDM) cosmological
simulations which include gas-dynamics, radiative cooling, star formation,
supernova feedback, and metal enrichment. Two such disk galaxies are analyzed,
and HI column density and velocity distributions in all-sky Aitoff projections
are constructed. The simulations demonstrate that LCDM is able to create
galaxies with sufficient numbers of anomalous velocity gas clouds consistent
with the HVCs observed within the MW, and that they are found within a
galactocentric radius of 150 kpc. We also find that one of the galaxies has a
polar gas ring, with radius 30 kpc, which appears as a large structure of HVCs
in the Aitoff projection. Such large structures may share an origin similar to
extended HVCs observed in the MW, such as Complex C.Comment: Accepted by ApJL, 08 Jun 2006. 5 pages, 5 figures, 1 table. LaTeX
(emulateapj.cls). File with high resolution images available at
http://astronomy.swin.edu.au/~tconnors/publications/ . References added;
discussion added to, but conclusions unchange
Successful recovery of infective endocarditis-induced rapidly progressive glomerulonephritis by steroid therapy combined with antibiotics: a case report
BACKGROUND: The mortality rate among patients with infective endocarditis, especially associated with the presence of complications or coexisting conditions such as renal failure and the use of combined medical and surgical therapy remains still high. Prolonged parenteral administration of a bactericidal antimicrobial agent or combination of agents is usually recommended, however, the optimal therapy for infective endocarditis associated with renal injury is not adequately defined. CASE PRESENTATION: Patient was a 24-years old man who presented to our hospital with fever, fatigue, and rapidly progressive glomerulonephritis. He had a history of ventricular septum defect (VSD). A renal biopsy specimen revealed crescentic glomerulonephritis and echocardiogram revealed VSD with vegetation on the tricuspid valve. Specimens of blood demonstrated Propionibacterium Acnes. The intensive antibiotic therapy with penicillin G was started without clinical improvement of renal function or resolution of fever over the next 7 days. After the short-term treatment of low dose of corticosteroid combined with continuous antibiotics, high fever and renal insufficiency were dramatically improved. CONCLUSION: Although renal function in our case worsened despite therapy with antibiotics, a short-term and low dose of corticosteroid therapy with antibiotics was able to recover renal function and the patient finally underwent tricuspid valve-plasty and VSD closure. We suggest that the patients with rapidly progressive glomerulonephritis associated with infective endocarditis might be treated with a short-term and low dose of corticosteroid successfully
Methanogenic archaea use a bacteria-like methyltransferase system to demethoxylate aromatic compounds
Methane-generating archaea drive the final step in anaerobic organic compound mineralization and dictate the carbon flow of Earthâs diverse anoxic ecosystems in the absence of inorganic electron acceptors. Although such Archaea were presumed to be restricted to life on simple compounds like hydrogen (H(2)), acetate or methanol, an archaeon, Methermicoccus shengliensis, was recently found to convert methoxylated aromatic compounds to methane. Methoxylated aromatic compounds are important components of lignin and coal, and are present in most subsurface sediments. Despite the novelty of such a methoxydotrophic archaeon its metabolism has not yet been explored. In this study, transcriptomics and proteomics reveal that under methoxydotrophic growth M. shengliensis expresses an O-demethylation/methyltransferase system related to the one used by acetogenic bacteria. Enzymatic assays provide evidence for a two step-mechanisms in which the methyl-group from the methoxy compound is (1) transferred on cobalamin and (2) further transferred on the C(1)-carrier tetrahydromethanopterin, a mechanism distinct from conventional methanogenic methyl-transfer systems which use coenzyme M as final acceptor. We further hypothesize that this likely leads to an atypical use of the methanogenesis pathway that derives cellular energy from methyl transfer (Mtr) rather than electron transfer (F(420)H(2) re-oxidation) as found for methylotrophic methanogenesis
Disk evolution since z=1 in a CDM Universe
Increasingly large populations of disk galaxies are now being observed at
increasingly high redshifts, providing new constraints on our knowledge of how
such galaxies evolve. Are these observations consistent with a cosmology in
which structures form hierarchically? To probe this question, we employ
SPH/N-body galaxy scale simulations of late-type galaxies. We examine the
evolution of these simulated disk galaxies from redshift 1 to 0, looking at the
mass-size and luminosity-size relations, and the thickness parameter, defined
as the ratio of scale-height to scale-length. The structural parameters of our
simulated disks settle down quickly, and after redshift z=1 the galaxies evolve
to become only slightly flatter. Our present day simulated galaxies are larger,
more massive, less bright, and redder than at z=1. The inside-out nature of the
growth of our simulated galaxies reduces, and perhaps eliminates, expectations
of evolution in the size-mass relation.Comment: accepted version, to appear in ApJ 01 March 2006, v63
Acute Pancreatitis due to pH-Dependent Mesalazine That Occurred in the Course of Ulcerative Colitis
We report the case of a 26-year-old male who presented with acute pancreatitis during the course of treatment for pancolitic ulcerative colitis (UC) with a time-dependent mesalazine formulation, prednisolone and azathioprine (AZA). Despite a review of his clinical history and various tests, the cause of pancreatitis could not be determined. Since drug-induced pancreatitis was considered possible, administration of the time-dependent mesalazine preparation and AZA was discontinued, and conservative treatment for acute pancreatitis was performed. The pancreatitis promptly improved with these treatments, but drug lymphocyte stimulation test (DLST) for both the time-dependent mesalazine formulation and AZA was negative. A pH-dependent mesalazine formulation was given for maintenance therapy of UC. Subsequently, as the pancreatitis relapsed, drug-induced pancreatitis was strongly suspected. Administration of mesalazine was discontinued, and pancreatitis was smoothly in remission by conservative treatment. According to the positive DLST result for the pH-dependent mesalazine formulation and the clinical course, a diagnosis of pH-dependent mesalazine-induced pancreatitis due to this formulation was made. During the clinical course of UC, occurrence of drug-induced pancreatitis must always be considered
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