5,892 research outputs found
An Approach to Study the Body Back Discomfort of Economy Class Aircraft Passenger
The paper describes the questionnaire study that was designed to unfold the relationship between different body back discomfort levels over time. One hundred and four anonymous self administered questionnaires were completed at Schipol International Airport, the Netherlands from October through November 2008. Long haul economy class aircraft passengers are at risk of uncomfortable for long hour sitting and experience significant uncomfortable at different body back parts such as arm, neck and lower leg
A stochastic derivation of the geodesic rule
We argue that the geodesic rule, for global defects, is a consequence of the
randomness of the values of the Goldstone field in each causally
connected volume. As these volumes collide and coalescence, evolves by
performing a random walk on the vacuum manifold . We derive a
Fokker-Planck equation that describes the continuum limit of this process. Its
fundamental solution is the heat kernel on , whose leading
asymptotic behavior establishes the geodesic rule.Comment: 12 pages, No figures. To be published in Int. Jour. Mod. Phys.
A Bayesian approach to estimate changes in condom use from limited human immunodeficiency virus prevalence data.
Evaluation of large-scale intervention programmes against human immunodeficiency virus (HIV) is becoming increasingly important, but impact estimates frequently hinge on knowledge of changes in behaviour such as the frequency of condom use over time, or other self-reported behaviour changes, for which we generally have limited or potentially biased data. We employ a Bayesian inference methodology that incorporates an HIV transmission dynamics model to estimate condom use time trends from HIV prevalence data. Estimation is implemented via particle Markov chain Monte Carlo methods, applied for the first time in this context. The preliminary choice of the formulation for the time varying parameter reflecting the proportion of condom use is critical in the context studied, because of the very limited amount of condom use and HIV data available. We consider various novel formulations to explore the trajectory of condom use over time, based on diffusion-driven trajectories and smooth sigmoid curves. Numerical simulations indicate that informative results can be obtained regarding the amplitude of the increase in condom use during an intervention, with good levels of sensitivity and specificity performance in effectively detecting changes. The application of this method to a real life problem demonstrates how it can help in evaluating HIV interventions based on a small number of prevalence estimates, and it opens the way to similar applications in different contexts
CHANGES OF FORCE AND SPEED CHARACTERISTICS IN MALES AND FEMALES EIGHT TO FIFTY YEARS OLD
The purpose of this study was to determine changes of force and speed characteristics in male and female subjects from eight to 50 years old. Four hundred and eighteen sedentary subjects grouped by age from eight to 50 years old were tested for several force and speed indicators. One-way ANOVA revealed that the majority (four out of six) of force and speed characteristics showed significant increases in subjects up to 30 years of age and subsequent significant decreases. The remaining two indicators showed continuous decline throughout the tested lifespan. It is suggested that these results may be used as a criterion which may assist in promoting physical activity and sport beyond the age of 30 years
Plasma free amino acid profile in quiescent Inflammatory Bowel Disease patients orally administered with Mastiha (Pistacia lentiscus); a randomised clinical trial
Background: Natural products have been studied regarding their effectiveness on Inflammatory Bowel Disease (IBD). Hypothesis/Purpose: To examine the effects of Mastiha (Pistacia lentiscus var. Chia) on clinical course and amino acid (AA) profile of patients in remission. Study design: This is a randomised, double-blind, placebo-controlled clinical trial. Methods: Patients (n = 68) were randomly allocated to Mastiha (2.8 g/day) or placebo adjunct to stable medication. Free AAs were identified applying Gas Chromatography-Mass Spectrometry in plasma. Medical-dietary history, Inflammatory Bowel Disease Questionnaire, Harvey-Bradshaw Index, Partial Mayo Score, biochemical, faecal and blood inflammatory markers were assessed. Primary endpoint was the clinical relapse rate at 6 months. Secondary endpoints included variations in free AAs, inflammatory biomarkers and quality of life. Statistical significance was set at 0.05. Results: Concerning AAs and biochemical data, alanine (p = 0.006), valine (p = 0.047), proline (p = 0.022), glutamine (p < 0.001) and tyrosine (p = 0.043) along with total cholesterol (p = 0.032) and LDL cholesterol (p = 0.045) increased only in placebo group compared with baseline and the change between the study groups was significantly different. Inflammatory markers had not a significantly different change between the two groups, even serum IL-6, faecal calprotectin and faecal lactoferrin increased only in the placebo group. Although Mastiha was not proven superior to placebo in remission rate (17.6% vs. 23.5%, p = 0.549), attenuation in increase of free AAs levels in verum group is reported. Conclusion: Mastiha inhibited an increase in plasma free AAs seen in patients with quiescent IBD. Since change of AAs is considered an early prognostic marker of disease activity, this indicates a potential role of Mastiha in remission maintenance
Bayesian epidemic models for spatially aggregated count data
Epidemic data often possess certain characteristics, such as the presence of many zeros, the spatial nature of the disease spread mechanism, environmental noise, serial correlation and dependence on time varying factors. This paper addresses these issues via suitable Bayesian modelling. In doing so we utilise a general class of stochastic regression models appropriate for spatio-temporal count data with an excess number of zeros. The developed regression framework does incorporate serial correlation and time varying covariates through an Ornstein Uhlenbeck process formulation. In addition, we explore the effect of different priors, including default options and variations of mixtures of g-priors. The effect of different distance kernels for the epidemic model component is investigated. We proceed by developing branching process-based methods for testing scenarios for disease control, thus linking traditional epidemiological models with stochastic epidemic processes, useful in policy-focused decision making. The approach is illustrated with an application to a sheep pox dataset from the Evros region, Greece
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Measurement of jet multiplicity distributions in [Formula: see text] production in pp collisions at [Formula: see text].
The normalised differential top quark-antiquark production cross section is measured as a function of the jet multiplicity in proton-proton collisions at a centre-of-mass energy of 7[Formula: see text] at the LHC with the CMS detector. The measurement is performed in both the dilepton and lepton+jets decay channels using data corresponding to an integrated luminosity of 5.0[Formula: see text]. Using a procedure to associate jets to decay products of the top quarks, the differential cross section of the [Formula: see text] production is determined as a function of the additional jet multiplicity in the lepton+jets channel. Furthermore, the fraction of events with no additional jets is measured in the dilepton channel, as a function of the threshold on the jet transverse momentum. The measurements are compared with predictions from perturbative quantum chromodynamics and no significant deviations are observed
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Probing color coherence effects in pp collisions at [Formula: see text].
A study of color coherence effects in pp collisions at a center-of-mass energy of 7[Formula: see text] is presented. The data used in the analysis were collected in 2010 with the CMS detector at the LHC and correspond to an integrated luminosity of 36 pb[Formula: see text]. Events are selected that contain at least three jets and where the two jets with the largest transverse momentum exhibit a back-to-back topology. The measured angular correlation between the second- and third-leading jet is shown to be sensitive to color coherence effects, and is compared to the predictions of Monte Carlo models with various implementations of color coherence. None of the models describe the data satisfactorily
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