Examining Gender Differences in the Relationship Between Active Travel and Fitness Outcomes

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Wigner Oscillators, Twisted Hopf Algebras and Second Quantization

By correctly identifying the role of central extension in the centrally extended Heisenberg algebra h, we show that it is indeed possible to construct a Hopf algebraic structure on the corresponding enveloping algebra U(h) and eventually deform it through Drinfeld twist. This Hopf algebraic structure and its deformed version U^F(h) are shown to be induced from a more fundamental Hopf algebra obtained from the Schroedinger field/oscillator algebra and its deformed version, provided that the fields/oscillators are regarded as odd-elements of the super-algebra osp(1|2n). We also discuss the possible implications in the context of quantum statistics.Comment: 23 page

Comparison of College Student Hypertension Prevalence between the JNC7 and ACC/AHA Diagnostic Criteria

International Journal of Exercise Science 12(3): 898-903, 2019. Hypertension is highly prevalent and associated with non-communicable diseases and increased premature mortality risk. However, the impact of the new hypertension diagnostic criteria on the prevalence of hypertension diagnoses has yet to be examined among college students. The purpose of this study was to compare the prevalence of hypertension between the JNC7 and the ACC/AHA hypertension diagnostic criteria among college students. The blood pressure of 5,945 college students was assessed, and chi-square tests for independence examined differences between JNC7 and ACC/AHA criteria. The mean age of participants was 21.30 ± 1.05 years, and the majority identified as men (60.5%). Men were found to have significantly higher systolic (p \u3c .001, η2 = .10) and diastolic (p \u3c .001, η2 = .04) blood pressure, so all analyses were separated by sex. Hypertension guideline changes resulted in significant changes in hypertension categorization of both men, χ2 = 7,178, p \u3c .001, Фc = .816 and women, χ2 = 4,670, p \u3c .001, Фc = .816. Under the JNC7 guidelines, 292 (8.2%) men and 67 (2.8%) women were hypertensive. Using the ACC/AHA guidelines, 1455 (40.5%) men and 521 (22.3%) women were hypertensive. Hypertension guideline changes resulted in a significant increase in the prevalence of hypertension among college students, highlighting the potential demand for targeted prevention programs focused on fostering healthy lifestyle behaviors, i.e. physical activity and healthy eating, among students

Obesity in Switzerland: do estimates depend on how body mass index has been assessed?

In Switzerland monitoring of obesity in the general population is based on body mass index (BMI) derived from self-reported weight and height. This approach may lead to misclassification of obese subjects and misinterpretation of obesity prevalence and trends. In order to explore this potential bias, we compared studies with measured and self-reported data. We analysed five studies based on measured BMI and five studies based on self-reported BMI, all of which were carried out in Switzerland between 1977 and 2004 and encompassed men and women aged 35-74 years. Obesity was defined as BMI>or=30 kg/m2. The prevalence of obesity was markedly higher (1.6 times) in studies with measured BMI in both sexes: 14.2% vs 8.8% in men and 12.5% vs 7.9% in women. These differences tended to increase with age in both sexes. However, a similar upward trend in the prevalence of obesity was observed with both methods (absolute increase per year in men and women respectively: 0.24% and 0.25% using measured BMI vs 0.17% and 0.20% using self-reported BMI). In Switzerland obesity prevalence in adults has clearly increased in the past three decades. Although the use of self-reported height and weight leads to a valid estimation of this increase, it results in a considerable underestimation of obesity prevalence rates in Switzerland. The type of assessment of height and weight should be taken into consideration when comparing prevalences of obesity between studies or regions or when using these prevalences to assess associated health risks or costs

Exact Evolution Operator on Non-compact Group Manifolds

Free quantal motion on group manifolds is considered. The Hamiltonian is given by the Laplace -- Beltrami operator on the group manifold, and the purpose is to get the (Feynman's) evolution kernel. The spectral expansion, which produced a series of the representation characters for the evolution kernel in the compact case, does not exist for non-compact group, where the spectrum is not bounded. In this work real analytical groups are investigated, some of which are of interest for physics. An integral representation for the evolution operator is obtained in terms of the Green function, i.e. the solution to the Helmholz equation on the group manifold. The alternative series expressions for the evolution operator are reconstructed from the same integral representation, the spectral expansion (when exists) and the sum over classical paths. For non-compact groups, the latter can be interpreted as the (exact) semi-classical approximation, like in the compact case. The explicit form of the evolution operator is obtained for a number of non-compact groups.Comment: 32 pages, 5 postscript figures, LaTe

Self-energy of a scalar charge near higher-dimensional black holes

We study the problem of self-energy of charges in higher dimensional static spacetimes. Application of regularization methods of quantum field theory to calculation of the classical self-energy of charges leads to model-independent results. The correction to the self-energy of a scalar charge due to the gravitational field of black holes of the higher dimensional Majumdar-Papapetrou spacetime is calculated exactly. It proves to be zero in even dimensions, but it acquires non-zero value in odd dimensional spacetimes. The origin of the self-energy correction in odd dimensions is similar to the origin the conformal anomalies in quantum field theory in even dimensional spacetimes.Comment: 9 page

Pulse Profiles, Accretion Column Dips and a Flare in GX 1+4 During a Faint State

The Rossi X-ray Timing Explorer (RXTE) spacecraft observed the X-ray pulsar GX 1+4 for a period of 34 hours on July 19/20 1996. The source faded from an intensity of ~20 mCrab to a minimum of <~0.7 mCrab and then partially recovered towards the end of the observation. This extended minimum lasted ~40,000 seconds. Phase folded light curves at a barycentric rotation period of 124.36568 +/- 0.00020 seconds show that near the center of the extended minimum the source stopped pulsing in the traditional sense but retained a weak dip feature at the rotation period. Away from the extended minimum the dips are progressively narrower at higher energies and may be interpreted as obscurations or eclipses of the hot spot by the accretion column. The pulse profile changed from leading-edge bright before the extended minimum to trailing-edge bright after it. Data from the Burst and Transient Source Experiment (BATSE) show that a torque reversal occurred <10 days after our observation. Our data indicate that the observed rotation departs from a constant period with a Pdot/P value of ~-1.5% per year at a 4.5 sigma significance. We infer that we may have serendipitously obtained data, with high sensitivity and temporal resolution about the time of an accretion disk spin reversal. We also observed a rapid flare which had some precursor activity, close to the center of the extended minimum.Comment: 19 pages, 6 figures, accepted for publication in Astrophysical Journal (tentatively scheduled for vol. 529 #1, 20 Jan 2000

Dynamical noncommutativity

The model of dynamical noncommutativity is proposed. The system consists of two interrelated parts. The first of them describes the physical degrees of freedom with coordinates q^1, q^2, the second one corresponds to the noncommutativity r which has a proper dynamics. After quantization the commutator of two physical coordinates is proportional to the function of r. The interesting feature of our model is the dependence of nonlocality on the energy of the system. The more the energy, the more the nonlocality. The lidding contribution is due to the mode of noncommutativity, however, the physical degrees of freedom also contribute in nonlocality in higher orders in \theta.Comment: published versio

Hard diffraction in hadron--hadron interactions and in photoproduction

Hard single diffractive processes are studied within the framework of the triple--Pomeron approximation. Using a Pomeron structure function motivated by Regge--theory we obtain parton distribution functions which do not obey momentum sum rule. Based on Regge-- factorization cross sections for hard diffraction are calculated. Furthermore, the model is applied to hard diffractive particle production in photoproduction and in $p\bar{p}$ interactions.Comment: 13 pages, Latex, 13 uuencoded figure

The quantum state vector in phase space and Gabor's windowed Fourier transform

Representations of quantum state vectors by complex phase space amplitudes, complementing the description of the density operator by the Wigner function, have been defined by applying the Weyl-Wigner transform to dyadic operators, linear in the state vector and anti-linear in a fixed `window state vector'. Here aspects of this construction are explored, with emphasis on the connection with Gabor's `windowed Fourier transform'. The amplitudes that arise for simple quantum states from various choices of window are presented as illustrations. Generalized Bargmann representations of the state vector appear as special cases, associated with Gaussian windows. For every choice of window, amplitudes lie in a corresponding linear subspace of square-integrable functions on phase space. A generalized Born interpretation of amplitudes is described, with both the Wigner function and a generalized Husimi function appearing as quantities linear in an amplitude and anti-linear in its complex conjugate. Schr\"odinger's time-dependent and time-independent equations are represented on phase space amplitudes, and their solutions described in simple cases.Comment: 36 pages, 6 figures. Revised in light of referees' comments, and further references adde