9,695 research outputs found
Active commuting is associated with a lower risk of obesity, diabetes and metabolic syndrome in Chilean adults
Background:
There is limited evidence on how active commuting is associated with health benefits in developing countries. The aim of this study therefore was to investigate the associations between active commuting and markers of adiposity and cardiometabolic risk in the Chilean adult population.
Methods:
In total, 5157 participants from the Chilean National Health Survey 2009–10 were included in this cross-sectional study. Active commuting was measured using the Global Physical Activity Questionnaire (GPAQ v2). Body mass index (BMI) and waist circumference (WC) were measured and used to define obesity and central obesity. Type 2 diabetes (T2D) and metabolic syndrome were determined using WHO and updated ATPIII-NCEP criteria, respectively.
Results:
The main finding of this study is that a 30 min increase in active commuting is associated with lower odds for BMI > 25.0 kg m−2 (0.93 [95% CI: 0.88–0.98, P = 0.010]). Similarly, the odds for central obesity was 0.87 [0.82–0.92, P < 0.0001]. Similar associations were found for T2D (0.81 [0.75–0.88], P < 0.0001) and metabolic syndrome (OR: 0.86 [0.80–0.92], P < 0.0001).
Conclusion:
Our findings show that active commuting is associated with lower adiposity and a healthier metabolic profile including lower risk for obesity, diabetes and metabolic syndrome
WIYN Imaging of the Globular Cluster Systems of the Spiral Galaxies NGC891 and NGC4013
We present results from a WIYN 3.5m telescope imaging study of the globular
cluster (GC) systems of the edge-on spiral galaxies NGC891 and NGC4013. We used
the 10' x 10' Minimosaic Imager to observe the galaxies in BVR filters to
projected radii of ~20 kpc from the galaxy centers. We combined the WIYN data
with archival and published data from WFPC2 and ACS on the Hubble Space
Telescope to assess the contamination level of the WIYN GC candidate sample and
to follow the GC systems further in toward the galaxies' centers. We
constructed radial distributions for the GC systems using both the WIYN and HST
data. The GC systems of NGC891 and NGC4013 extend to 9+/-3 kpc and 14+/-5 kpc,
respectively, before falling off to undetectable levels in our images. We use
the radial distributions to calculate global values for the total number (N_GC)
and specific frequencies (S_N and T) of GCs. NGC4013 has N_GC = 140+/-20, S_N =
1.0+/-0.2 and T = 1.9+/-0.5; our N_GC value is ~40% smaller than a previous
determination from the literature. The HST data were especially useful for
NGC891, because the GC system is concentrated toward the plane of the galaxy
and was only weakly detected in our WIYN images. Although NGC891 is thought to
resemble the Milky Way in its overall properties, it has only half as many GCs,
with N_GC = 70+/-20, S_N = 0.3+/-0.1 and T = 0.6+/-0.3. We also calculate the
galaxy-mass-normalized number of blue (metal-poor) GCs in NGC891 and NGC4013
and find that they fall along a general trend of increasing specific frequency
of blue GCs with increasing galaxy mass. Given currently available resources,
the optimal method for studying the global properties of extragalactic GC
systems is to combine HST data with wide-field, ground-based imaging with good
resolution. The results here demonstrate the advantage gained by using both
methods when possible.Comment: 43 pages, 11 figures 6 tables; accepted to The Astronomical Journal.
Online AJ version at http://iopscience.iop.org/1538-3881/140/2/430
Real Space Renormalization Group Methods and Quantum Groups
We apply real-space RG methods to study two quantum group invariant
Hamiltonians, that of the XXZ model and the Ising model in a transverse field
defined in an open chain with appropiate boundary terms. The quantum group
symmetry is preserved under the RG transformation except for the appearence of
a quantum group anomalous term which vanishes in the classical case. We obtain
correctly the line of critical XXZ models. In the ITF model the RG-flow
coincides with the tensor product decomposition of cyclic irreps. of
with .Comment: 7 pages, LATEX, no figure
Warped Supersymmetric Grand Unification
We construct a realistic theory of grand unification in AdS_5 truncated by
branes, in which the unified gauge symmetry is broken by boundary conditions
and the electroweak scale is generated by the AdS warp factor. We show that the
theory preserves the successful gauge coupling unification of the 4D MSSM at
leading-logarithmic level. Kaluza-Klein (KK) towers, including those of XY
gauge and colored Higgs multiplets, appear at the TeV scale, while the extra
dimension provides natural mechanisms for doublet-triplet splitting and proton
decay suppression. In one possible scenario supersymmetry is strongly broken on
the TeV brane, in which case the lightest SU(3)_C x SU(2)_L x U(1)_Y gauginos
are approximately Dirac and the mass of the lightest XY gaugino is pushed well
below that of the lowest gauge boson KK mode, improving the prospects for its
production at the LHC. The bulk Lagrangian possesses a symmetry that we call
GUT parity. If GUT parity is exact, the lightest GUT particle, most likely an
XY gaugino, is stable. Once produced in a collider, the XY gaugino hadronizes
to form mesons, some of which will be charged and visible as highly ionizing
tracks. The lightest supersymmetric particle is the gravitino of mass \sim
10^{-3} eV, which is also stable if R parity is conserved.Comment: 41 pages, LaTeX, version to appear in Phys. Rev.
Standard Model Higgs from Higher Dimensional Gauge Fields
We consider the possibility that the standard model Higgs fields may
originate from extra components of higher dimensional gauge fields. Theories of
this type considered before have had problems accommodating the standard model
fermion content and Yukawa couplings different from the gauge coupling.
Considering orbifolds based on abelian discrete groups we are lead to a 6
dimensional G_2 gauge theory compactified on T^2/Z_4. This theory can naturally
produce the SM Higgs fields with the right quantum numbers while predicting the
value of the weak mixing angle sin^2 theta_W = 0.25 at the tree-level, close to
the experimentally observed one. The quartic scalar coupling for the Higgs is
generated by the higher dimensional gauge interaction and predicts the
existence of a light Higgs. We point out that one can write a quadratically
divergent counter term for Higgs mass localized to the orbifold fixed point.
However, we calculate these operators and show that higher dimensional gauge
interactions do not generate them at least at one loop. Fermions are introduced
at orbifold fixed points, making it easy to accommodate the standard model
fermion content. Yukawa interactions are generated by Wilson lines. They may be
generated by the exchange of massive bulk fermions, and the fermion mass
hierarchy can be obtained. Around a TeV, the first KK modes would appear as
well as additional fermion modes localized at the fixed point needed to cancel
the quadratic divergences from the Yukawa interactions. The cutoff scale of the
theory could be a few times 10 TeV.Comment: 29 pages, 1 figure, LaTeX. v2: Section on the absence of tadpole at
all order removed. Typos corrected. Refs. added. Final version appeared in
PR
NectarCAM : a camera for the medium size telescopes of the Cherenkov Telescope Array
NectarCAM is a camera proposed for the medium-sized telescopes of the
Cherenkov Telescope Array (CTA) covering the central energy range of ~100 GeV
to ~30 TeV. It has a modular design and is based on the NECTAr chip, at the
heart of which is a GHz sampling Switched Capacitor Array and a 12-bit Analog
to Digital converter. The camera will be equipped with 265 7-photomultiplier
modules, covering a field of view of 8 degrees. Each module includes the
photomultiplier bases, high voltage supply, pre-amplifier, trigger, readout and
Ethernet transceiver. The recorded events last between a few nanoseconds and
tens of nanoseconds. The camera trigger will be flexible so as to minimize the
read-out dead-time of the NECTAr chips. NectarCAM is designed to sustain a data
rate of more than 4 kHz with less than 5\% dead time. The camera concept, the
design and tests of the various subcomponents and results of thermal and
electrical prototypes are presented. The design includes the mechanical
structure, cooling of the electronics, read-out, clock distribution, slow
control, data-acquisition, triggering, monitoring and services.Comment: In Proceedings of the 34th International Cosmic Ray Conference
(ICRC2015), The Hague, The Netherlands. All CTA contributions at
arXiv:1508.0589
Statistics of Q-Oscillators, Quons and Relation to Fractional Satistics
The statistics of -oscillators, quons and to some extent, of anyons are
studied and the basic differences among these objects are pointed out. In
particular, the statistical distributions for different bosonic and fermionic
-oscillators are found for their corresponding Fock space representations in
the case when the hamiltonian is identified with the number operator. In this
case and for nonrelativistic particles, the single-particle temperature Green
function is defined with -deformed periodicity conditions. The equations of
state for nonrelativistic and ultrarelativistic bosonic -gases in an
arbitrary space dimension are found near Bose statistics, as well as the one
for an anyonic gas near Bose and Fermi statistics. The first corrections to the
second virial coefficients are also evaluated. The phenomenon of Bose-Einstein
condensation in the -deformed gases is also discussed.Comment: 21 pages, Latex, HU-TFT-93-2
Caribbean Corals in Crisis: Record Thermal Stress, Bleaching, and Mortality in 2005
BACKGROUND. The rising temperature of the world's oceans has become a major threat to coral reefs globally as the severity and frequency of mass coral bleaching and mortality events increase. In 2005, high ocean temperatures in the tropical Atlantic and Caribbean resulted in the most severe bleaching event ever recorded in the basin. METHODOLOGY/PRINCIPAL FINDINGS. Satellite-based tools provided warnings for coral reef managers and scientists, guiding both the timing and location of researchers' field observations as anomalously warm conditions developed and spread across the greater Caribbean region from June to October 2005. Field surveys of bleaching and mortality exceeded prior efforts in detail and extent, and provided a new standard for documenting the effects of bleaching and for testing nowcast and forecast products. Collaborators from 22 countries undertook the most comprehensive documentation of basin-scale bleaching to date and found that over 80% of corals bleached and over 40% died at many sites. The most severe bleaching coincided with waters nearest a western Atlantic warm pool that was centered off the northern end of the Lesser Antilles. CONCLUSIONS/SIGNIFICANCE. Thermal stress during the 2005 event exceeded any observed from the Caribbean in the prior 20 years, and regionally-averaged temperatures were the warmest in over 150 years. Comparison of satellite data against field surveys demonstrated a significant predictive relationship between accumulated heat stress (measured using NOAA Coral Reef Watch's Degree Heating Weeks) and bleaching intensity. This severe, widespread bleaching and mortality will undoubtedly have long-term consequences for reef ecosystems and suggests a troubled future for tropical marine ecosystems under a warming climate.NOAA Coral Reef Conservation Progra
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