2,196 research outputs found
Enterococcus faecalis capsular polysaccharide serotypes C and D and their contributions to host innate immune evasion
It has become increasingly difficult to treat infections caused by Enterococcus faecalis due to the high levels of intrinsic and acquired antibiotic resistances. However, few studies have explored the mechanisms that E. faecalis employs to circumvent the host innate immune response and establish infection. Capsule polysaccharides are important virulence factors that are associated with innate immune evasion. We demonstrate that capsule producing E. faecalis strains of either serotype C or D are more resistant to complement-mediated opsonophagocytosis compared to un-encapsulated strains using cultured macrophages (RAW 264.7). We show that differences in opsonophagocytosis are not due to variation in C3 deposition, but due to the ability of capsule to mask bound C3 from detection on the surface of E. faecalis. Similarly, E. faecalis capsule masks detection of lipoteichoic acid which correlates with decreased TNF-α production by cultured macrophages in the presence of encapsulated strains compared to unencapsulated strains. Our studies confirm the important role of the capsule as a virulence factor of E. faecalis, and provide several mechanisms by which the presence of the capsule influences evasion of the innate immune response, and suggest that the capsule could be a potential target for developing alternative therapies to treat E. faecalis infections
Higher-Loop Corrections to the Infrared Evolution of a Gauge Theory with Fermions
We consider a vectorial, asymptotically free gauge theory and analyze the
effect of higher-loop corrections to the beta function on the evolution of the
theory from the ultraviolet to the infrared. We study the case in which the
theory contains copies of a fermion transforming according to the
fundamental representation and several higher-dimensional representations of
the gauge group. We also calculate higher-loop values of the anomalous
dimension of the mass, of at the infrared zero of the
beta function. We find that for a given theory, the values of
calculated to three- and four-loop order, and evaluated at the infrared zero
computed to the same order, tend to be somewhat smaller than the value
calculated to two-loop order. The results are compared with recent lattice
simulations.Comment: 22 pages, latex, matches Phys. Rev. D publicatio
Microorganism Cultivation Platform for Human Life Support
A life support system for providing a growth medium for at least one photosynthetic micro-organism and for converting CO2 to O2, with reduced water use that is as low as about 4 percent of the corresponding amount of water normally required for conventional micro-organism growth. The system includes a liquid transport capillary channel, a mixed culture photosynthetic biofilm and a liquid transport substrate that is positioned between and contiguous to the capillary channel and the biofilm, where the liquid transport rate is adjustable by adjustment of the local humidity. Approximately uniform radiation is received by the biofilm and contributes to microorganism growth
A Prototype Decision Support Tool for Ballast Water Risk Management using a Combination of Hydrodynamic Models and Agent-Based Modelling
We report the development of a prototype Decision Support Tool (DST) for modelling the risks of spreading of non-indegenous invasive species via ballast water. The DST constitutes of two types of models: A 3D hydrodynamical model calculates the currents in the North Sea and Danish Straits, and an agent-based model estimates the dispersal of selected model organisms with the prevailing currents calculated by the 3D hydrodynamical model. The analysis is concluded by a post processing activity, where scenarios of dispersal are combined into an interim estimate of connectivity within the study area. The latter can be used as a tool for assessment of potential risk associated with intentional or unintentional discharges of ballast water. We discuss how this prototype DST can be used for ballast water risk management and outline other functions and uses, e.g. in regard to ecosystem-based management and the implementation of the EU Marine Strategy Framework Directive.https://commons.wmu.se/nsbwo/1001/thumbnail.jp
Toward TeV Conformality
We study the chiral condensate for an SU(3) gauge theory
with massless Dirac fermions in the fundamental representation when
is increased from 2 to 6. For , our lattice simulations of , where is the Nambu-Goldstone-boson decay constant, agree with
the measured QCD value. For , this ratio shows significant
enhancement, presaging an even larger enhancement anticipated as
increases further, toward the critical value for transition from confinement to
infrared conformality.Comment: 4 pages, 4 figures. v2: revised version for PR
Age-specific vaccine effectiveness of seasonal 2010/2011 and pandemic influenza A(H1N1) 2009 vaccines in preventing influenza in the United Kingdom
An analysis was undertaken to measure age-specific vaccine effectiveness (VE) of 2010/11 trivalent seasonal influenza vaccine (TIV) and monovalent 2009 pandemic influenza vaccine (PIV) administered in 2009/2010. The test-negative case-control study design was employed based on patients consulting primary care. Overall TIV effectiveness, adjusted for age and month, against confirmed influenza A(H1N1)pdm 2009 infection was 56% (95% CI 42–66); age-specific adjusted VE was 87% (95% CI 45–97) in <5-year-olds and 84% (95% CI 27–97) in 5- to 14-year-olds. Adjusted VE for PIV was only 28% (95% CI x6 to 51) overall and 72% (95% CI 15–91) in <5-year-olds. For confirmed influenza B infection, TIV effectiveness was 57% (95% CI 42–68) and in 5- to 14-year-olds 75% (95% CI 32–91). TIV provided moderate protection against the main circulating strains in 2010/2011, with higher protection in children. PIV administered during the previous season provided residual protection after 1 year, particularly in the <5 years age group
Leptoproduction of J/psi
We study leptoproduction of at large within the
nonrelativistic QCD (NRQCD) factorization formalism. The cross section is
dominated by color-octet terms that are of order . The color-singlet
term, which is of order , is shown to be a small contribution to
the total cross section. We also calculate the tree diagrams for color-octet
production at order in a region of phase space where there is no
leading color-octet contribution. We find that in this regime the color-singlet
contribution dominates. We argue that non-perturbative corrections arising from
diffractive leptoproduction, higher twist effects, and higher order terms in
the NRQCD velocity expansion should be suppressed as is increased.
Therefore, the color-octet matrix elements can be reliably extracted from this process.
Finally, we point out that an experimental measurement of the polarization of
leptoproduced will provide an excellent test of the NRQCD
factorization formalism.Comment: 33 pages latex. 10 figures. Uses revtex, epsf, and rotate macros.
This paper is also available via the UW phenomenology archives at
http://phenom.physics.wisc.edu/pub/preprints
General hardware multicasting for fine-grained message-passing architectures
Manycore architectures are increasingly favouring message-passing or partitioned global address spaces (PGAS) over cache coherency for reasons of power efficiency and scalability. However, in the absence of cache coherency, there can be a lack of hardware support for one-to-many communication patterns, which are prevalent in some application domains. To address this, we present new hardware primitives for multicast communication in rack-scale manycore systems. These primitives guarantee delivery to both colocated and distributed destinations, and can capture large unstructured communication patterns precisely. As a result, reliable multicast transfers among any number of software tasks, connected in any topology, can be fully offloaded to hardware. We implement the new primitives in a research platform consisting of 50K RISC-V threads distributed over 48 FPGAs, and demonstrate significant performance benefits on a range of applications expressed using a high-level vertex-centric programming model
Approaching Conformality with Ten Flavors
We present first results for lattice simulations, on a single volume, of the
low-lying spectrum of an SU(3) Yang-Mills gauge theory with ten light fermions
in the fundamental representation. Fits to the fermion mass dependence of
various observables are found to be globally consistent with the hypothesis
that this theory is within or just outside the strongly-coupled edge of the
conformal window, with mass anomalous dimension consistent with 1 over the
range of scales simulated. We stress that we cannot rule out the possibility of
spontaneous chiral-symmetry breaking at scales well below our infrared cutoff.
We discuss important systematic effects, including finite-volume corrections,
and consider directions for future improvement.Comment: 7 pages, 3 figures. Submitted to Physical Review Letters. v2:
corrected global fits. v3: corrected estimation of confidence interval
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