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

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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

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

Large-scale shifts in phytoplankton groups in the Equatorial Pacific during ENSO cycles

The El Niño Southern Oscillation (ENSO) drives important changes in the marine productivity of the Equatorial Pacific, in particular during major El Niño/La Niña transitions. Changes in environmental conditions associated with these climatic events also likely impact phytoplankton composition. In this work, the distribution of four major phytoplankton groups (nanoeucaryotes, Prochlorococcus, Synechococcus, and diatoms) was examined between 1996 and 2007 by applying the PHYSAT algorithm to the ocean color data archive from the Ocean Color and Temperature Sensor (OCTS) and Sea-viewing Wide Field-of-view Sensor (SeaWiFS). Coincident with the decrease in chlorophyll concentrations, a large-scale shift in the phytoplankton composition of the Equatorial Pacific, that was characterized by a decrease in Synechococcus and an increase in nanoeucaryote dominance, was observed during the early stages of both the strong El Niño of 1997 and the moderate El Niño of 2006. A significant increase in diatoms dominance was observed in the Equatorial Pacific during the 1998 La Niña and was associated with elevated marine productivity. An analysis of the environmental variables using a coupled physical-biogeochemical model (NEMO-PISCES) suggests that the Synechococcus dominance decrease during the two El Niño events was associated with an abrupt decline in nutrient availability (−0.9 to −2.5 μM NO3 month−1). Alternatively, increased nutrient availability (3 μM NO3 month−1) during the 1998 La Niña resulted in Equatorial Pacific dominance diatom increase. Despite these phytoplankton community shifts, the mean composition is restored after a few months, which suggests resilience in community structure

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

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

Initial State: Theory Status

I present a brief discussion of the different approaches to the study initial state effects in heavy ion collisions in view of the recent results from Pb+Pb and p+p collisions at the LHC.Comment: 8 pages, 6 figures. Contribution to the proceedings of the XXII International Conference on Ultrarelativistic Nucleus-Nucleus Collisions, QM2011. Annecy, France, 22-28 May 201

Wigner phase space distribution as a wave function

We demonstrate that the Wigner function of a pure quantum state is a wave function in a specially tuned Dirac bra-ket formalism and argue that the Wigner function is in fact a probability amplitude for the quantum particle to be at a certain point of the classical phase space. Additionally, we establish that in the classical limit, the Wigner function transforms into a classical Koopman-von Neumann wave function rather than into a classical probability distribution. Since probability amplitude need not be positive, our findings provide an alternative outlook on the Wigner function's negativity.Comment: 6 pages and 2 figure

Non-positivity of Groenewold operators

A central feature in the Hilbert space formulation of classical mechanics is the quantisation of classical Liouville densities, leading to what may be termed term Groenewold operators. We investigate the spectra of the Groenewold operators that correspond to Gaussian and to certain uniform Liouville densities. We show that when the classical coordinate-momentum uncertainty product falls below Heisenberg's limit, the Groenewold operators in the Gaussian case develop negative eigenvalues and eigenvalues larger than 1. However, in the uniform case, negative eigenvalues are shown to persist for arbitrarily large values of the classical uncertainty product.Comment: 9 pages, 1 figures, submitted to Europhysics Letter