231 research outputs found
Deforming tachyon kinks and tachyon potentials
In this paper we investigate deformation of tachyon potentials and tachyon
kink solutions. We consider the deformation of a DBI type action with gauge and
tachyon fields living on D1-brane and D3-brane world-volume. We deform tachyon
potentials to get other consistent tachyon potentials by using properly a
deformation function depending on the gauge field components. Resolutions of
singular tachyon kinks via deformation and applications of deformed tachyon
potentials to scalar cosmology scenario are discussed.Comment: To appear in JHEP, 19 pages, 5 eps figures, minor changes and one
reference adde
Dynamic structure factor of the Ising model with purely relaxational dynamics
We compute the dynamic structure factor for the Ising model with a purely
relaxational dynamics (model A). We perform a perturbative calculation in the
expansion, at two loops in the high-temperature phase and at one
loop in the temperature magnetic-field plane, and a Monte Carlo simulation in
the high-temperature phase. We find that the dynamic structure factor is very
well approximated by its mean-field Gaussian form up to moderately large values
of the frequency and momentum . In the region we can investigate,
, , where is the correlation
length and the zero-momentum autocorrelation time, deviations are at
most of a few percent.Comment: 21 pages, 3 figure
Renal tubular damage and worsening renal function in chronic heart failure: Clinical determinants and relation to prognosis (Bio-SHiFT study)
Background: It is uncertain that chronic heart failure (CHF) patients are susceptible to renal tubular damage with that of worsening renal function (WRF) preceding clinical outcomes. Hypothesis: Changes in tubular damage biomarkers are stronger predictors of subsequent clinical events than changes in creatinine (Cr), and both have different clinical determinants. Methods: During 2.2 years, we repeatedly simultaneously collected a median of 9 blood and 8 urine samples per patient in 263 CHF patients. We determined the slopes (rates of change) of the biomarker trajectories for plasma (Cr) and urinary tubular damage biomarkers N-acetyl-β-d-glucosaminidase (NAG), and kidney-injury-molecule (KIM)-1. The degree of tubular injury was ranked according to NAG and KIM-1 slopes: increase in neither, increase in either, or increase in both; WRF was defined as increasing Cr slope. The composite endpoint comprised HF-hospitalization, cardiac death, left ventricular assist device placement, and heart transplantation. Results: Higher baseline NT-proBNP and lower eGFR predicted more severe tubular damage (adjusted odds ratio, adj. OR [95%CI, 95% confidence interval] per doubling NT-proBNP: 1.26 [1.07-1.49]; per 10 mL/min/1.73 m2 eGFR decrease 1.16 [1.03-1.31]). Higher loop diuretic doses, lower aldosterone antagonist doses, and higher eGFR predicted WRF (furosemide per 40 mg increase: 1.32 [1.08-1.62]; spironolactone per 25 mg decrease: 1.76 [1.07-2.89]; per 10 mL/min/1.73 m2 eGFR increase: 1.40 [1.20-1.63]). WRF and higher rank of tubular injury individually entailed higher risk of the composite endpoint (adjusted hazard ratios, adj. HR [95%CI]: WRF 1.9 [1.1-3.4], tubular 8.4 [2.6-27.9]; when combined risk was highest 15.0 [2.0-111.0]). Conclusion: Slopes of tubular damage and WRF biomarkers had different clinical determinants. Both predicted clinical outcome, but this association was stronger for tubular injury. Prognostic effects of both appeared independent and additive
Not All Arms of IgM Are Equal: Following Hinge-Directed Cleavage by Online Native SEC-Orbitrap-Based CDMS
Immunoglobulins M (IgM) are key natural antibodies produced initially in humoral immune response. Due to their large molecular weights and extensive glycosylation loads, IgMs represent a challenging target for conventional mass analysis. Charge detection mass spectrometry (CDMS) may provide a unique approach to tackle heterogeneous IgM assemblies, although this technique can be quite laborious and technically challenging. Here, we describe the use of online size exclusion chromatography (SEC) to automate buffer exchange and sample introduction, and demonstrate its adaptability with Orbitrap-based CDMS. We discuss optimal experimental parameters for online SEC-CDMS experiments, including ion activation, choice of column, and resolution. Using this approach, CDMS histograms containing hundreds of individual ion signals can be obtained in as little as 5 min from single injections of <1 μg of sample. To demonstrate the unique utility of online SEC-CDMS, we performed real-time kinetic monitoring of pentameric IgM digestion by the protease IgMBRAZOR, which cleaves specifically in the hinge region of IgM. Several digestion intermediates corresponding to processive losses of F(ab’)2 subunits could be mass-resolved and identified by SEC-CDMS. Interestingly, we find that for the J-chain linked IgM pentamer, cleavage of one of the F(ab’)2 subunits is much slower than the other four F(ab’)2 subunits, which we attribute to the symmetry-breaking interactions of the J-chain within the pentameric IgM structure. The online SEC-CDMS methodologies described here open new avenues into the higher throughput automated analysis of heterogeneous, high-mass protein assemblies by CDMS
Phylogeographic analysis reveals multiple international transmission events have driven the global emergence of Escherichia coli O157:H7
This work was supported by: Scotland by Food Standards Scotland [Grant Number FS102029] and University of Aberdeen; New Zealand, Institute of Environmental Science and Research; Canada, the Public Health Agency of Canada; United States, United States Department of AgriculturePeer reviewedPostprin
New Effective Feynman-like Rules for the Multi-Regge QCD Asymptotics of Inclusive Multijet Production
New effective Feynman-like rules are defined for inclusive multijet cross
sections in the multi-Regge regime. The solution of the BFKL equation is used
as a starting point. The resulting rules involve conformal weight and rapidity
as a momentum and a coordinate respectively and are translation invariant in
the coordinates. We use the effective rules to calculate ultra high energy
asymptotics of inclusive multijet production. The dependence on the parton
densities occurs only in the overall normalization of the asymptotic cross
sections.Comment: 12 pages in Latex, 3 figs by epsfig, refs update
The LUNEX5 project
http://accelconf.web.cern.ch/AccelConf/FEL2012/papers/froa03.pdfInternational audienceLUNEX5 (free electron Laser Using a New accelerator for the Exploitation of X-ray radiation of 5th generation) aims at investigating the production of short, intense, and coherent pulses in the soft X-ray region. The project consists of a Free Electron Laser (FEL) line enabling the most advanced seeding configurations: High order Harmonic in Gas (HHG) seeding and Echo Enable Harmonic Generation (EEHG) with in-vacuum (potentially cryogenic) undulators of 15 and 30 mm period. Two accelerator types feed this FEL line : a 400 MeV Conventional Linear Accelerator (CLA) using superconducting cavities compatible with a future upgrade towards high repetition rate, for the investigations of the advanced FEL schemes; and a 0.4 - 1 GeV Laser Wake Field Accelerator (LWFA), to be qualified in view of FEL application, in the single spike or seeded regime. Two pilot user experiments for timeresolved studies of isolated species and solid state matter dynamics will take benefit of LUNEX5 FEL radiation and provide feedback of the performance of the different schemes under real user conditions
Predictors of Poor Neurocognitive Performance and Neuropsychological Phenotypes in Adolescents and Young Adults With Congenital Heart Disease
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