66 research outputs found
Two-dimensional tetramer-cuprate Na5RbCu4(AsO4)4Cl2: phase transitions and AFMorder as seen by 87Rb NMR
We report the Rb nuclear magnetic resonance (NMR) results in a recently
synthesized Na5RbCu4(AsO4)Cl2. This complex novel two-dimensional (2D) cuprate
is an unique magnetic material, which contains layers of coupled Cu4O4
tetramers. In zero applied magnetic field, it orders antiferromagnetically via
a second-order low-entropy phase transition at TN = 15(1) K. We characterise
the ordered state by 87Rb NMR, and suggest for it a noncollinear rather than
collinear arrangement of spins. We discuss the properties of Rb nuclear site
and point out the new structural phase transition(s) around 74 K and 110 K.Comment: 2 pages, 2 figures, Proceedings of SCES'05, Vienna 200
Text messaging (SMS) as a tool to facilitate weight loss and prevent metabolic deterioration in clinically healthy overweight and obese subjects : a randomised controlled trial
Publisher Copyright: © 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.Objective: To examine whether SMS text messaging facilitates a reduction of weight and waist circumference (WC) and favourable changes in lipid profile and insulin levels in clinically healthy overweight and obese subjects. Design: A randomised controlled trial. Setting and intervention: Primary care health centre in Riga, Latvia. Text messaging once in two weeks. Subjects: A total of 123 overweight and obese men and women aged 30–45 years with no cardiovascular diseases (CVDs) or diabetes. Main outcome measures: changes in anthropometric parameters (weight, WC, body mass index (BMI)) and biochemical parameters (lipids, fasting glucose and insulin). Results: We found a statistically significant decrease in weight (2.4%), BMI and WC (4.8%) in the intervention group, while the control group showed a statistically non-significant increase in weight and BMI and decrease in WC. Between group results obtained over the course of a year showed statistically significant mean differences between weight (–3.4 kg (95% CI –5.5, –1.3)), BMI kg/m2 (–1.14 (95% CI –1.9, –0.41)), WC (–4.6 cm (95% CI –6.8, –2.3)), hip circumference (–4.0 cm (95% CI –5.9, –2.0)) and fasting insulin (2.43 μU/ml (95% CI 0.6, 4.3)). Mean differences of changes in glucose and lipid levels were statistically non significant: fasting glucose (–0.01 mmol/l (95% CI –0.19, 0.17)), TC mmol/l (–0.04 mmol/l (95% CI –0.29, 0.21)), HDL-C (0.14 mmol/l (95% CI –0.65, 0.09)), LDL-C (–0.02 mmol/l (95% CI –0.22, 0.18)) and TG (0.23 mmol/l (95% CI –0.06, 0.52)). Conclusions: SMS messaging in clinically healthy overweight and obese subjects facilitates a slight decrease in weight, BMI and WC. It is anticipated that the implications of this strategy might facilitate the design of preventive and promotive strategies among high risk groups in Latvia.publishersversionPeer reviewe
Chemical equilibration and thermal dilepton production from the quark gluon plasma at finite baryon density
The chemical equilibration of a highly unsaturated quark-gluon plasma has
been studied at finite baryon density. It is found that in the presence of
small amount of baryon density, the chemical equilibration for gluon becomes
slower and the temperature decreases less steeply as compared to the baryon
free plasma. As a result, the space time integrated yield of dilepton is
enhanced if the initial temperature of the plasma is held fixed. Even at a
fixed initial energy density, the suppression of the dilepton yields at higher
baryo-chemical potential is compensated, to a large extent, by the slow cooling
of the plasma.Comment: Latex, 19 pages, 8 postscript figures. To appear in Phys. Rev.
Anomalous specific heat in high-density QED and QCD
Long-range quasi-static gauge-boson interactions lead to anomalous
(non-Fermi-liquid) behavior of the specific heat in the low-temperature limit
of an electron or quark gas with a leading term. We obtain
perturbative results beyond the leading log approximation and find that
dynamical screening gives rise to a low-temperature series involving also
anomalous fractional powers . We determine their coefficients in
perturbation theory up to and including order and compare with exact
numerical results obtained in the large- limit of QED and QCD.Comment: REVTEX4, 6 pages, 2 figures; v2: minor improvements, references
added; v3: factor of 2 error in the T^(7/3) coefficient corrected and plots
update
Effect of baryon density on parton production, chemical equilibration and thermal photon emission from quark gluon plasma
The effect of baryon density on parton production processes of
and is studied
using full phase space distribution function and also with inclusion of quantum
statistics i.e. Pauli blocking and Bose enhancement factors, in the case of
both saturated and unsaturated quark gluon plasma. The rate for the process is found to be much less as compared to the most
commonly used factorized result obtained on the basis of classical
approximation. This discrepancy, which is found both at zero as well as at
finite baryon densities, however, is not due to the lack of quantum statistics
in the classical approximation, rather due to the use of Fermi-Dirac and
Bose-Einstein distribution functions for partons instead of Boltzmann
distribution which is appropriate under such approximation. Interestingly, the
rates of parton production are found to be insensitive to the baryo-chemical
potential particularly when the plasma is unsaturated although the process of
chemical equilibration strongly depends on it. The thermal photon yields, have
been calculated specifically from unsaturated plasma at finite baryon density.
The exact results obtained numerically are found to be in close agreement with
the analytic expression derived using factorized distribution functions
appropriate for unsaturated plasma. Further, it is shown that in the case of
unsaturated plasma, the thermal photon production is enhanced with increasing
baryon density both at fixed temperature and fixed energy density of the quark
gluon plasma.Comment: Latex, 24 pages, 6 postscript figures. Submitted to Phys. Rev.
A first order transition and parity violation in a color superconductor
In cold, dense quark matter, quarks of different flavor can form Cooper pairs
which are anti-triplets under color and have total spin J=0. The transition to
a phase where strange quarks condense with either up or down quarks is driven
first order by the Coleman-Weinberg mechanism. At densities sufficiently high
to (effectively) restore the axial U(1) symmetry, then relative to the ordinary
vacuum, the condensation of up with down quarks (effectively) breaks parity
spontaneously.Comment: 4 pages, ReVTeX, final versio
Two lectures on color superconductivity
The first lecture provides an introduction to the physics of color
superconductivity in cold dense quark matter. The main color superconducting
phases are briefly described and their properties are listed. The second
lecture covers recent developments in studies of color superconducting phases
in neutral and beta-equilibrated matter. The properties of gapless color
superconducting phases are discussed.Comment: 56 pages, 9 figures. Minor corrections and references added. Lectures
delivered at the IARD 2004 conference, Saas Fee, Switzerland, June 12 - 19,
2004, and at the Helmholtz International Summer School and Workshop on Hot
points in Astrophysics and Cosmology, JINR, Dubna, Russia, August 2 - 13,
200
Multidrug resistant pulmonary tuberculosis treatment regimens and patient outcomes: an individual patient data meta-analysis of 9,153 patients.
Treatment of multidrug resistant tuberculosis (MDR-TB) is lengthy, toxic, expensive, and has generally poor outcomes. We undertook an individual patient data meta-analysis to assess the impact on outcomes of the type, number, and duration of drugs used to treat MDR-TB
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