639 research outputs found
The noise properties of stochastic processes and entropy production
Based on a Fokker-Planck description of external Ornstein-Uhlenbeck noise and
cross-correlated noise processes driving a dynamical system we examine the
interplay of the properties of noise processes and the dissipative
characteristic of the dynamical system in the steady state entropy production
and flux. Our analysis is illustrated with appropriate examples.Comment: RevTex, 1 figure, To appear in Phys. Rev.
Awareness of vaccination status and its predictors among working people in Switzerland
BACKGROUND: Adult vaccination status may be difficult to obtain, often requiring providers to rely on individual patient recall. To determine vaccination status awareness and the sociodemographic predictors of awareness for tetanus, hepatitis A and B, tick born encephalitis (TBE) and influenza vaccination. METHODS: Multivariate analyses were used to evaluate a questionnaire survey of 10 321 employees (4070 women and 6251 men aged 15–72 years) of two companies in Switzerland. RESULTS: Among 10 321 respondents, 75.5% reported knowing their tetanus vaccination status, 64.1% hepatitis A, 61.1% hepatitis B, 64.3% TBE and 71.9% influenza. Between 1 in 4 and 1 in 3 employees were not aware of their vaccination status. Differences in awareness for the five vaccinations considered correlated with gender and language. These differences persisted in multivariate analyses. CONCLUSION: Women employees, German-speaking employees and employees who paid more attention to their diet were more often aware of their vaccination status. A more reliable and readily accessible data source for vaccination status is needed in order to capitalize on opportunities to update vaccinations among Swiss employees
Highly tunable magnetic spirals and electric polarization in Gd0.5Dy0.5MnO3
Recent progress in the field of multiferroics led to the discovery of many new materials in which ferroelectricity is induced by cycloidal spiral orders. The direction of the electric polarization is typically constrained by spin anisotropies and magnetic field. Here, we report that the mixed rare-earth manganite, Gd0.5Dy0.5MnO3, exhibits a spontaneous electric polarization along a general direction in the crystallographic ac plane, which is suppressed below 10 K but reemerges in an applied magnetic field. Neutron-diffraction measurements show that the polarization direction results from a large tilt of the spiral plane with respect to the crystallographic axes and that the suppression of ferroelectricity is caused by the transformation of a cycloidal spiral into a helical one, a unique property of this rare-earth manganite. The freedom in the orientation of the spiral plane allows for a fine magnetic control of ferroelectricity, i.e., a rotation as well as a strong enhancement of the polarization depending on the magnetic-field direction. We show that this unusual behavior originates from the coupling between the transition-metal and rare-earth magnetic subsystems
Crossover of the high-energy spin fluctuations from collective triplons to localized magnetic excitations in doped Sr14-xCaxCu24O41 cuprate ladders
We studied the magnetic excitations in the quasi-one-dimensional (q-1D)
ladder subsystem of Sr_(14-x) Ca_x Cu_24 O_41(SCCO) using Cu L_3-edge resonant
inelastic X-ray scattering (RIXS). By comparing momentum-resolved RIXS spectra
with (x=12.2) and without (x=0) high Ca content, we track the evolution of the
magnetic excitations from collective two-triplon (2T) excitations (x=0) to
weakly-dispersive gapped modes at an energy of 280 meV (x=12.2). Density matrix
renormalization group (DMRG) calculations of the RIXS response in the doped
ladders suggest that the flat magnetic dispersion and damped excitation profile
observed at x=12.2 originates from enhanced hole localization. This
interpretation is supported by polarization-dependent RIXS measurements, where
we disentangle the spin-conserving {\Delta}S=0 scattering from the predominant
{\Delta}S=1 spin-flip signal in the RIXS spectra. The results show that the
low-energy weight in the {\Delta}S=0 channel is depleted when Sr is replaced by
Ca, consistent with a reduced carrier mobility. Our results demonstrate that
off-ladder impurities can affect both the low-energy magnetic excitations and
superconducting correlations in the CuO_4 plaquettes. Finally, our study
characterizes the magnetic and charge fluctuations in the phase from which
superconductivity emerges in SCCO at elevated pressures
Genetic diversity and population structure analysis of isolates of the rice false smut pathogen Ustilaginoidea virens in India.
Not AvailableGenetic diversity assessment and population structure analysis are essential for char acterization of pathogens and their isolates. Markers are essential tools for explor ing genetic variation among the isolates. False smut of rice caused by Ustilaginoidea
virens, formerly Villosiclava virens, is a major emerging disease of rice in India. A high
level of variability is observed at the field level, but no information is available from
India on genetic diversity and population structure. This is the first report of genetic
diversity and population structure of U. virens from India that included 63 isolates dis tributed across the vast geographical area of eastern and north-eastern India (18.9 to
26.7°N and 82.6 to 94.2°E). Seventeen RAPDs and 14 SSRs were identified as poly morphic and a total of 140 alleles were detected across the populations. The average
number of alleles per locus for each primer was 4.5. All the isolates were grouped
into two major clusters, with partial geographical segregation that was supported by
principal coordinate analysis. Mantel test suggested genetic distance within the iso lates increased with increasing geographical distance. Analysis of molecular variation
showed more genetic variation within populations and less among populations. This
outcome will help in understanding genetic diversity of U. virens from eastern and
north-eastern India and in planning effective management strategies
Quasi-one-dimensional magnetism in the spin-1/2 antiferromagnet BaNa2 Cu (VO4)2
We report synthesis and magnetic properties of quasi-one-dimensional spin-12 Heisenberg antiferromagnetic chain compound BaNa2Cu(VO4)2. This orthovanadate has a centrosymmetric crystal structure, C2/c, where the magnetic Cu2+ ions form spin chains. These chains are arranged in layers, with the chain direction changing by 62∘ between the two successive layers. Alternatively, the spin lattice can be viewed as anisotropic triangular layers upon taking the interchain interactions into consideration. Despite this potential structural complexity, temperature-dependent magnetic susceptibility, heat capacity, electron spin resonance intensity, and nuclear magnetic resonance (NMR) shift agree well with the uniform spin-1/2 Heisenberg chain model with an intrachain coupling of J/kB≃5.6 K. The saturation field obtained from the magnetic isotherm measurement consistently reproduces the value of J/kB. Further, the 51V NMR spin-lattice relaxation rate mimics the one-dimensional character in the intermediate temperature range, whereas magnetic long-range order sets in below TN≃0.25 K. The effective interchain coupling is estimated to be J⊥/kB≃0.1 K. The theoretical estimation of exchange couplings using band-structure calculations reciprocate our experimental findings and unambiguously establish the one-dimensional character of the compound. Finally, the spin lattice of BaNa2Cu(VO4)2 is compared with the chemically similar but not isostructural compound BaAg2Cu(VO4)2
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