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Cardiovascular Risk Factors and Dehydroepiandrosterone Sulfate Among Latinos in the Boston Puerto Rican Health Study.
Low blood dehydroepiandrosterone sulfate (DHEAS) levels have strong positive associations with stroke and coronary heart disease. However, it is unclear whether DHEAS is independently associated with cardiovascular risk factors. Therefore, we examined the association between cardiovascular risk factors and DHEAS concentration among a high-risk population of Latinos (Puerto Ricans aged 45 to 75 years at baseline) in a cross-sectional analysis of the Boston Puerto Rican Health Study. Of eligible participants, 72% completed baseline interviews and provided blood samples. Complete data were available for 1355 participants. Associations between cardiovascular risk factors (age, sex, total cholesterol, high-density lipid cholesterol, triglycerides, and glucose) and log-transformed DHEAS (μg/dL) were assessed. In robust multivariable regression analyses, DHEAS was significantly inversely associated with age (β = -12.4; 95% CI: -15.2, -9.7; per 5 years), being female (vs. male) (β = -46; 95% CI: -55.3, -36.6), and plasma triglyceride concentration (β = -0.2; 95% CI: -0.3, -0.1; per 10 mg/dL) and was positively associated with total cholesterol and plasma glucose levels (β = 1.8; 95% CI: 0.6, 3 and β = 0.2; 95% CI: 0.04, 0.3, respectively, per 10 mg/dL) after adjustment for smoking, alcohol, and physical activity and for postmenopausal hormone use in women. Estimates were unchanged after adjustment for measures of chronic disease and inflammation. Women exhibited a stronger age-related decline in DHEAS and a positive association with glucose in contrast to findings among men (P interaction < 0.05). In conclusion, in this large study of Latinos with a heavy cardiovascular risk factor burden, we observed significant associations between cardiovascular disease (CVD) risk factors and DHEAS, with variations by sex. These findings improve our understanding of the role DHEAS may play in CVD etiology
Molecules with a peptide link in protostellar shocks: a comprehensive study of L1157
Interstellar molecules with a peptide link -NH-C(=O)-, like formamide
(NHCHO), acetamide (NHCOCH) and isocyanic acid (HNCO) are
particularly interesting for their potential role in pre-biotic chemistry. We
have studied their emission in the protostellar shock regions L1157-B1 and
L1157-B2, with the IRAM 30m telescope, as part of the ASAI Large Program.
Analysis of the line profiles shows that the emission arises from the outflow
cavities associated with B1 and B2. Molecular abundance of
and are derived for
formamide and isocyanic acid, respectively, from a simple rotational diagram
analysis. Conversely, NHCOCH was not detected down to a relative
abundance of a few . B1 and B2 appear to be among the richest
Galactic sources of HNCO and NHCHO molecules. A tight linear correlation
between their abundances is observed, suggesting that the two species are
chemically related. Comparison with astrochemical models favours molecule
formation on ice grain mantles, with NHCHO generated from hydrogenation of
HNCO.Comment: 11 pages, 9 figures. Accepted for publication in MNRAS Main Journal.
Accepted 2014 August 19, in original form 2014 July
noise and integrable systems
An innovative test for detecting quantum chaos based on the analysis of the
spectral fluctuations regarded as a time series has been recently proposed.
According to this test, the fluctuations of a fully chaotic system should
exhibit 1/f noise, whereas for an integrable system this noise should obey the
1/f^2 power law. In this letter, we show that there is a family of well-known
integrable systems, namely spin chains of Haldane-Shastry type, whose spectral
fluctuations decay instead as 1/f^4. We present a simple theoretical
justification of this fact, and propose an alternative characterization of
quantum chaos versus integrability formulated directly in terms of the power
spectrum of the spacings of the unfolded spectrum.Comment: 5 pages, 3 figures, RevTe
New counterterms induced by trans-Planckian physics in semiclassical gravity
We consider free and self-interacting quantum scalar fields satisfying
modified dispersion relations in the framework of Einstein-Aether theory. Using
adiabatic regularization, we study the renormalization of the equation for the
mean value of the field in the self-interacting case, and the renormalization
of the semiclassical Einstein-Aether equations for free fields. In both cases
we consider Bianchi type I background spacetimes. Contrary to what happens for
{\it free} fields in {\it flat} Robertson-Walker spacetimes, the
self-interaction and/or the anisotropy produce non-purely geometric terms in
the adiabatic expansion, i.e terms that involve both the metric
and the aether field . We argue that, in a general spacetime, the
renormalization of the theory would involve new counterterms constructed with
and , generating a fine-tuning problem for the
Einstein-Aether theory
Nonlinear Interaction of Transversal Modes in a CO2 Laser
We show the possibility of achieving experimentally a Takens-Bogdanov
bifurcation for the nonlinear interaction of two transverse modes ()
in a laser. The system has a basic O(2) symmetry which is perturbed by
some symmetry-breaking effects that still preserve the symmetry. The
pattern dynamics near this codimension two bifurcation under such symmetries is
described. This dynamics changes drastically when the laser properties are
modified.Comment: 16 pages, 0 figure
Deuterium and N fractionation in NH during the formation of a Sun-like star
Although chemical models predict that the deuterium fractionation in
NH is a good evolutionary tracer in the star formation process, the
fractionation of nitrogen is still a poorly understood process. Recent models
have questioned the similar evolutionary trend expected for the two
fractionation mechanisms in NH, based on a classical scenario in which
ion-neutral reactions occurring in cold gas should have caused an enhancement
of the abundance of ND, NNH, and NNH. In the
framework of the ASAI IRAM-30m large program, we have investigated the
fractionation of deuterium and N in NH in the best known
representatives of the different evolutionary stages of the Sun-like star
formation process. The goal is to ultimately confirm (or deny) the classical
"ion-neutral reactions" scenario that predicts a similar trend for D and
N fractionation. We do not find any evolutionary trend of the
N/N ratio from both the NNH and NNH
isotopologues. Therefore, our findings confirm that, during the formation of a
Sun-like star, the core evolution is irrelevant in the fractionation of
N. The independence of the N/N ratio with time, found also
in high-mass star-forming cores, indicates that the enrichment in N
revealed in comets and protoplanetary disks is unlikely to happen at core
scales. Nevertheless, we have firmly confirmed the evolutionary trend expected
for the H/D ratio, with the NH/ND ratio decreasing before the
pre-stellar core phase, and increasing monotonically during the protostellar
phase. We have also confirmed clearly that the two fractionation mechanisms are
not related.Comment: 9 pages, 2 figures, accepted for publication in MNRA
Constraining New Forces in the Casimir Regime Using the Isoelectronic Technique
We report the first isoelectronic differential force measurements between a
Au-coated probe and two Au-coated films, made out of Au and Ge. These
measurements, performed at submicron separations using soft
microelectromechanical torsional oscillators, eliminate the need for a detailed
understanding of the probe-film Casimir interaction. The observed differential
signal is directly converted into limits on the parameters and
which characterize Yukawa-like deviations from Newtonian gravity. We
find \alpha \lsim 10^{12} for nm, an improvement of
10 over previous limits.Comment: 10 pages, 4 figure
Nonlinear Pseudo-Supersymmetry in the Framework of N-fold Supersymmetry
We recall the importance of recognizing the different mathematical nature of
various concepts relating to PT-symmetric quantum theories. After clarifying
the relation between supersymmetry and pseudo-supersymmetry, we prove
generically that nonlinear pseudo-supersymmetry, recently proposed by Sinha and
Roy, is just a special case of N-fold supersymmetry. In particular, we show
that all the models constructed by these authors have type A 2-fold
supersymmetry. Furthermore, we prove that an arbitrary one-body quantum
Hamiltonian which admits two (local) solutions in closed form belongs to type A
2-fold supersymmetry, irrespective of whether or not it is Hermitian,
PT-symmetric, pseudo-Hermitian, and so on.Comment: 10 pages, no figures; typos correcte
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