2,230 research outputs found

    Quick Cash + Web Sites to See

    Get PDF

    Fluctuating "order parameter" for a quantum chaotic system with partially broken time-reversal symmetry

    Full text link
    The functional defined as the squared modulus of the spatial average of the wave function squared, plays the role of an ``order parameter'' for the transition between Hamiltonian ensembles with orthogonal and unitary symmetry. Upon breaking time-reversal symmetry, the order parameter crosses over from one to zero. We compute its distribution in the crossover regime and find that it has large fluctuations around the ensemble average. These fluctuations imply long-range spatial correlations in the eigenfunction and non-Gaussian perturbations of eigenvalues, in precise agreement with results by Fal'ko and Efetov and by Taniguchi, Hashimoto, Simons, and Altshuler. As a third implication of the order-parameter fluctuations we find correlations in the response of an eigenvalue to independent perturbations of the system.Comment: 4 pages, REVTeX-3.0, 1 figure. Reference added to Y. V. Fyodorov and A. D. Mirlin, Phys. Rev. B 51, 13403 (1995

    Seroprevalence of bluetongue serotype 8 in cattle in the Netherlands in spring 2007, and its consequences

    Get PDF
    A cross-sectional study was carried out in spring 2007, at the end of the first bluetongue outbreak season, to determine the geographical spread of bluetongue virus serotype 8 (BTV-8) infection in cattle in the Netherlands and the consequences for some production parameters. Blood samples from cattle submitted to the laboratory of the Dutch Animal Health Service for other voluntary and obligatory health programmes were tested serologically for BTV-8. in total, 37,073 samples were tested and 659 (1.78 per cent) were seropositive. The samples came from 5436 herds, of which 45 per cent of herds had only one sample submitted from them. The prevalence was highest in the south of the country, where the outbreak had started, and decreased towards the north. in 340 herds more than 50 per cent of cattle were tested, of which 156 herds were located in infected compartments, and in 37 of these herds (10.9 per cent) at least one positive cow was detected. The average within-herd prevalence in the 37 herds was 39.3 per cent: 2.2 per cent in I I dairy herds, 68.4 per cent in 20 small-scale herds and 14 per cent in four suckler cow herds. The prevalence differed significantly between herd types but did not show a geographical trend. The average net return for milk production amounted to is an element of 2417/cow/year and it decreased significantly on average by is an element of 48/ cow/year in the bluetongue-infected dairy herds during the bluetongue period. on the small-scale farms, the incidence of mortality increased by 3.2 (95 per cent confidence interval [a] 1.2 to 9.1) times in the infected herds during the bluetongue period, but the voluntary culling rate decreased by a factor of 2.3 (95 per cent Cl 1.1 to 4.8)

    Thermopower of Single-Channel Disordered and Chaotic Conductors

    Get PDF
    We show (analytically and by numerical simulation) that the zero-temperature limit of the distribution of the thermopower S of a one-dimensional disordered wire in the localized regime is a Lorentzian, with a disorder-independent width of 4 pi^3 k_B^2 T/3e\Delta (where T is the temperature and \Delta the mean level spacing). Upon raising the temperature the distribution crosses over to an exponential form exp(-2|S|eT/\Delta). We also consider the case of a chaotic quantum dot with two single-channel ballistic point contacts. The distribution of S then has a cusp at S=0 and a tail |S|^{-1-\beta} log|S| for large S (with \beta=1,2 depending on the presence or absence of time-reversal symmetry).Comment: To be published in Superlattices and Microstructures, special issue on the occasion of Rolf Landauer's 70th birthda

    Design space exploration revisited

    Get PDF

    Reported adverse drug reactions during the use of inhaled steroids in children with asthma in the Netherlands

    Get PDF
    Objective: Inhaled corticosteroids (ICS) are widely used in the treatment of asthma. We studied the suspected adverse drug reactions (sADRs) reported during the use of ICS in the Netherlands. Methods: In the Netherlands, health professionals and patients can report suspected ADRs to the Pharmacovigilance Centre Lareb. All reported sADRs on ICS were categorised and assessed as to whether these were likely to be associated with use of the steroid. Age and gender adjusted Reported Odds Ratios (RORs) and Naranjo Scores (NS) were computed for sADRs reported more than 3 times. Results: Since 1984, sADRs of ICS were reported in 89 children (mean age 6 years), 48 (54%) were boys. Suspected drugs were fluticasone in 46 children (52%), budesonide in 21 (24%), and beclomethasone in 22 cases (24%). Psychiatric symptoms were reported in 19 children (21%; ROR 3.8, NS 3.6), growth retardation in 6 children (7%; ROR 47.8, NS 3.0) and rashes in 6 cases (7%; ROR 0.7, NS 2.4). There were 7 reports (8%; ROR 2.1, NS 3.4) concerning abnormalities of the teeth, 4 reports of alopecia (4%; ROR 3.3, NS 3.5), and 3 reports of hirsutism and hypertrichosis (NS 4.0). Non-fatal adrenal insufficiency was reported once. Conclusion: Alteration of behaviour was the most frequently reported sADR. There are more indications that alterations of behaviour could be a real sADR of ICS. Non-fatal adrenal insufficiency was the only reported possible life threatening sADR. The association of hypertrichosis and teeth abnormalities after ICS in children has not been reported in the literature before

    Changes in Exercise Habits of University Students During the Covid-19 Lockdown

    Get PDF
    The purpose of this investigation was to investigate how the exercise habits of college students changed during the COVID-19 pandemic lockdown. Data were collected via an online survey distributed through the University of Southern Maine student email distribution list. All current university students were invited to participate in the survey starting in February 2021 through March 2021. The study included a questionnaire designed to capture the exercise habits of university students three months before the lockdown of COVID-19 (January – March 2020) and their exercise habits after a lockdown in (February - April 2021). The survey questions were based on the American College of Sports Medicine (ACSM) physical activity guidelines to analyze the participant's exercise habits. The participants showed a decrease in the exercise along with an increase in weekly sitting time. Before COVID-19, 21.8% of participants were sitting >35 hours per week. After the COVID-19 lockdown, 50.45% of participants were sitting >35 hours per week. The results of this study could be used for further research to promote an increase in exercise at home. With the uncertainty of the pandemic, motivating people to stand and walk more could be the first step in breaking the increase in sitting habits and help to increase exercise habits. The COVID-19 pandemic has indeed imposed many restrictions on our daily routines, but it could also guide us to new approaches for prescribing exercise programs in the future

    Distribution of parametric conductance derivatives of a quantum dot

    Get PDF
    The conductance G of a quantum dot with single-mode ballistic point contacts depends sensitively on external parameters X, such as gate voltage and magnetic field. We calculate the joint distribution of G and dG/dX by relating it to the distribution of the Wigner-Smith time-delay matrix of a chaotic system. The distribution of dG/dX has a singularity at zero and algebraic tails. While G and dG/dX are correlated, the ratio of dG/dX and G(1−G)\sqrt{G(1-G)} is independent of G. Coulomb interactions change the distribution of dG/dX, by inducing a transition from the grand-canonical to the canonical ensemble. All these predictions can be tested in semiconductor microstructures or microwave cavities.Comment: 4 pages, RevTeX, 3 figure
    • …
    corecore