54,122 research outputs found
Finite Size Polyelectrolyte Bundles at Thermodynamic Equilibrium
We present the results of extensive computer simulations performed on
solutions of monodisperse charged rod-like polyelectrolytes in the presence of
trivalent counterions. To overcome energy barriers we used a combination of
parallel tempering and hybrid Monte Carlo techniques. Our results show that for
small values of the electrostatic interaction the solution mostly consists of
dispersed single rods. The potential of mean force between the polyelectrolyte
monomers yields an attractive interaction at short distances. For a range of
larger values of the Bjerrum length, we find finite size polyelectrolyte
bundles at thermodynamic equilibrium. Further increase of the Bjerrum length
eventually leads to phase separation and precipitation. We discuss the origin
of the observed thermodynamic stability of the finite size aggregates
Large magnetoresistance using hybrid spin filter devices
A magnetic "spin filter" tunnel barrier, sandwiched between a non-magnetic
metal and a magnetic metal, is used to create a new magnetoresistive tunnel
device, somewhat analogous to an optical polarizer-analyzer configuration. The
resistance of these trilayer structures depends on the relative magnetization
orientation of the spin filter and the ferromagnetic electrode. The spin
filtering in this configuration yields a previously unobserved
magnetoresistance effect, exceeding 100%.Comment: 3.5 pages, 3 figures, submitted to Appl. Phys. Let
Photocatalytic antimicrobial activity of thin surface films of TiO2, CuO and TiO2 /CuO dual layers on Escherichia coli and bacteriophage T4
TiO2 coated surfaces are increasingly studied for their ability to inactivate microorganisms. The activity of glass coated with thin films of TiO2, CuO and hybrid CuO/TiO2 prepared by atmospheric Chemical Vapour Deposition (Ap-CVD) and TiO2 prepared by a sol-gel process was investigated using the inactivation of bacteriophage T4 as a model for
inactivation of viruses. The chemical oxidising activity was also determined by measuring stearic acid oxidation. The results showed that the rate of inactivation of bacteriophage T4 increased with increasing chemical oxidising activity with the maximum rate obtained on
highly active sol-gel preparations. However these were delicate and easily damaged unlike the Ap-CVD coatings. Inactivation rates were highest on CuO and CuO/TiO2 which had the lowest chemical oxidising activities. The inactivation of T4 was higher than that of Escherichia coli on low activity surfaces. The combination of photocatalysis and toxicity of copper acted synergistically to inactivate bacteriophage T4 and retained some selfcleaning activity. The presence of phosphate ions slowed inactivation but NaCl had no effect. The results show that TiO2/CuO coated surfaces are highly antiviral and may have applications in the food and healthcare industries
Green Function of the Sutherland Model with SU(2) internal symmetry
We obtain the hole propagator of the Sutherland model with SU(2) internal
symmetry for coupling parameter , which is the simplest nontrivial
case. One created hole with spin down breaks into two quasiholes with spin down
and one quasihole with spin up. While these elementary excitations are
energetically free, the form factor reflects their anyonic character. The
expression for arbitrary integer is conjectured.Comment: 13pages, Revtex, one ps figur
Devenir professionnel de salariƩs des Pays de la Loire souffrant de troubles musculo-squelettiques
The objective was to study the employment and occupational outcomes of workers who were diagnosed with upper limb musculoskeletal disorders (UL-MSDs) or had complained of upper limb musculoskeletal pain a few years before, compared to workers without upper limb pain.
In 2002-2005, 83 occupational physicians examined 3,710 randomly selected workers. Three groups were constituted between 2007 and 2009: a āUL-MSDā group (workers with a clinically diagnosed UL-MSD); a āMS PAINā group (workers with pain in the previous seven days and without any clinically diagnosed form); and a āHEALTHYā group (workers with no disorder or upper limb pain).
A total of 2,287 responded to a questionnaire. Fewer subjects were still working in the āUL-MSDā group (79.3%) than in the āMS PAINā (85.9%) and āHEALTHYā (90.4%) groups. Among the subjects still working, 24% had changed their position in the same company in the āMS PAINā group, compared to 21% in the āUL-MSDā group, and 19% in the āHEALTHYā group.
This study showed the impact of UL-MSDs on employment outcome and of musculoskeletal pain on occupational outcome
Employment and occupational outcomes of workers with musculoskeletal pain in a French region
OBJECTIVES: To study the employment and occupational outcomes of workers who were diagnosed with upper limb musculoskeletal disorders (UL-MSDs) or had complained of upper limb musculoskeletal pain a few years before compared with workers who had no upper limb pain.
METHODS: In 2002-2005, an epidemiological surveillance system was set up. Occupational physicians examined 3710 randomly selected workers. It focused on six UL-MSDs: rotator cuff syndrome, lateral epicondylitis, flexor-extensor peritendinitis of the hands and fingers, de Quervain\u27s disease, carpal tunnel syndrome and ulnar tunnel syndrome. Three groups were constituted: a \u27UL-MSD\u27 group (workers with a clinically diagnosed UL-MSD at baseline, 13% of the cohort); a \u27PAIN\u27 group (workers with pain in the previous 7 days at baseline and without any clinically diagnosed form, 38%); and a \u27HEALTHY\u27 group (workers with no disorder or upper limb pain in the previous 7 days, 49%). They completed a questionnaire between 2007 and 2009.
RESULTS: A total of 2332 responded. Fewer subjects were still in work in the \u27UL-MSD\u27 group (79.3%) than in the \u27PAIN\u27 (85.9%) and \u27HEALTHY\u27 (90.4%) groups, the difference remaining significant after adjusting for gender, age, occupational category, type of company and comorbidities. Of the subjects still in work, 24% had changed their work station in the same company in the \u27PAIN\u27 group compared with 19% in the \u27HEALTHY\u27 group and 21% in the \u27UL-MSD\u27 group.
CONCLUSIONS: This study showed the impact of musculoskeletal pain on employment outcome and the difficulty of keeping workers with musculoskeletal problems at work
Sparse Deterministic Approximation of Bayesian Inverse Problems
We present a parametric deterministic formulation of Bayesian inverse
problems with input parameter from infinite dimensional, separable Banach
spaces. In this formulation, the forward problems are parametric, deterministic
elliptic partial differential equations, and the inverse problem is to
determine the unknown, parametric deterministic coefficients from noisy
observations comprising linear functionals of the solution.
We prove a generalized polynomial chaos representation of the posterior
density with respect to the prior measure, given noisy observational data. We
analyze the sparsity of the posterior density in terms of the summability of
the input data's coefficient sequence. To this end, we estimate the
fluctuations in the prior. We exhibit sufficient conditions on the prior model
in order for approximations of the posterior density to converge at a given
algebraic rate, in terms of the number of unknowns appearing in the
parameteric representation of the prior measure. Similar sparsity and
approximation results are also exhibited for the solution and covariance of the
elliptic partial differential equation under the posterior. These results then
form the basis for efficient uncertainty quantification, in the presence of
data with noise
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