126 research outputs found
Stability of 1+1 dimensional causal relativistic viscous hydrodynamics
The stability of the 1+1 dimensional solution of Israel-Stewart theory is
investigated. Firstly, the evolution of the temperature and the ratio of the
bulk pressure over the equilibrium pressure of the background is explored. Then
the stability with linear perturbations is studied by using the Lyapunov direct
method. It shows that the shear viscosity may weaken the instability induced by
the large peak of bulk viscosity around the phase transition temperature .Comment: 18 pages, 4 figures, 1 table; to be published in Nuclear Physics
Bose-Einstein Correlations of Charged Kaons in Central Pb+Pb Collisions at
Bose-Einstein correlations of charged kaons were measured near mid-rapidity
in central Pb+Pb collisions at 158 AGeV by the NA49 experiment at the
CERN SPS. Source radii were extracted using the Yano-Koonin-Podgoretsky and
Bertsch-Pratt parameterizations. The results are compared to published pion
data. The measured dependence for kaons and pions is consistent with
collective transverse expansion of the source and a freeze-out time of about
9.5 .Comment: 14 pages with 7 figures, submitted to Phys. Lett.
Longitudinal scaling property of the charge balance function in Au + Au collisions at 200 GeV
We present measurements of the charge balance function, from the charged
particles, for diverse pseudorapidity and transverse momentum ranges in Au + Au
collisions at 200 GeV using the STAR detector at RHIC. We observe that the
balance function is boost-invariant within the pseudorapidity coverage [-1.3,
1.3]. The balance function properly scaled by the width of the observed
pseudorapidity window does not depend on the position or size of the
pseudorapidity window. This scaling property also holds for particles in
different transverse momentum ranges. In addition, we find that the width of
the balance function decreases monotonically with increasing transverse
momentum for all centrality classes.Comment: 6 pages, 3 figure
Latin American consumption of major food groups: Results from the ELANS study
Background
The Latin American (LA) region is still facing an ongoing epidemiological transition and shows a complex public health scenario regarding non-communicable diseases (NCDs). A healthy diet and consumption of specific food groups may decrease the risk of NCDs, however there is a lack of dietary intake data in LA countries.
Objective
Provide updated data on the dietary intake of key science-based selected food groups related to NCDs risk in LA countries.
Design
ELANS (Latin American Study of Nutrition and Health) is a multicenter cross-sectional study assessing food consumption from an urban sample between15 to 65 years old from 8 LA countries (Argentina, Brazil, Chile, Colombia, Costa Rica, Ecuador, Peru, and Venezuela). Two 24-HR were obtained from 9, 218 individuals. The daily intake of 10 food groups related to NCDs risk (fruits; vegetables; legumes/beans; nuts and seeds; whole grains products; fish and seafood; yogurt; red meat; processed meats; sugar-sweetened beverages (ready-to-drink and homemade)) were assessed and compared to global recommendations. Results Only 7.2% of the overall sample reached WHO's recommendation for fruits and vegetables consumption (400 grams per day). Regarding the dietary patterns related to a reduced risk of NCDs, among the overall sample legumes and fruits were the food groups with closer intake to the recommendation, although much lower than expected (13.1% and 11.5%, respectively). Less than 3.5% of the sample met the optimal consumption level of vegetables, nuts, whole grains, fish and yogurt. Largest country-dependent differences in average daily consumption were found for legumes, nuts, fish, and yogurt. Mean consumption of SSB showed large differences between countries.
Conclusion
Diet intake quality is deficient for nutrient-dense food groups, suggesting a higher risk for NCDs in the urban LA region in upcoming decades. These data provide relevant and up-to-date information to take urgent public health actions to improve consumption of critically foods in order to prevent NCDs. Copyright
Three-Dimensional two-pion source image from Pb+Pb Collisions at Sqrts_NN=17.3 GeV: New constraints for source breakup dynamics
Source imaging methodology is used to provide a three-dimensional two-pion
source function for mid-rapidity pion pairs with MeV/c in central
() Pb+Pb collisions at =17.3 GeV. Prominent non-Gaussian
tails are observed in the pion pair transverse momentum (outward) and in the
beam (longitudinal) directions. Model calculations reproduce them with the
assumption of Bjorken longitudinal boost invariance and transverse flow
blast-wave dynamics coupled with "outside-in burning" in the transverse
direction; they also yield a proper time for breakup and emission duration for
the pion source.Comment: Six pages 4 figs. Submitted for publicatio
New computer technology: special issue «Cloud technologies in education»
The materials of the special issue are devoted to the use of cloud technologies in open education, the formation and development of a cloud-oriented learning environment, the use of cloud-based learning support systems, cloud technologies for learning mathematics, physics and informatics.
For scientists, employees of educational management bodies, teachers and students of higher educational institutions and colleges, teachers and graduate students, for all those who are interested in history, modern approaches to research and trends in the development of cloud technologies in education.Материалы спецвыпуска посвящены вопросам использования облачных технологий в открытом образовании, формирования и развития облачно ориентированной учебной среды, использованию облачно ориентированных систем поддержки обучения, средствам облачных технологий обучения математике, физике и информатике.
Для научных работников, работников органов управления образованием, преподавателей и студентов высших учебных заведений и колледжей, учителей и аспирантов, для всех тех, кого интересуют история, современные подходы к исследованию и тенденции развития облачных технологий в образовании.Матеріали спецвипуску присвячені питанням використання хмарних технологій у відкритій освіті, формування та розвитку хмаро орієнтованого навчального середовища, використанню хмаро орієнтованих систем підтримки навчання, засобам хмарних технологій навчання математики, фізик та інформатики.
Для науковців, працівників органів управління освітою, викладачів та студентів вищих навчальних закладів та коледжів, вчителів та аспірантів, для всіх тих, кого цікавлять історія, сучасні підходи до дослідження та тенденції розвитку хмарних технологій в освіті
Distribution of Major Health Risks: Findings from the Global Burden of Disease Study
BACKGROUND: Most analyses of risks to health focus on the total burden of their aggregate effects. The distribution of risk-factor-attributable disease burden, for example by age or exposure level, can inform the selection and targeting of specific interventions and programs, and increase cost-effectiveness. METHODS AND FINDINGS: For 26 selected risk factors, expert working groups conducted comprehensive reviews of data on risk-factor exposure and hazard for 14 epidemiological subregions of the world, by age and sex. Age-sex-subregion-population attributable fractions were estimated and applied to the mortality and burden of disease estimates from the World Health Organization Global Burden of Disease database. Where possible, exposure levels were assessed as continuous measures, or as multiple categories. The proportion of risk-factor-attributable burden in different population subgroups, defined by age, sex, and exposure level, was estimated. For major cardiovascular risk factors (blood pressure, cholesterol, tobacco use, fruit and vegetable intake, body mass index, and physical inactivity) 43%–61% of attributable disease burden occurred between the ages of 15 and 59 y, and 87% of alcohol-attributable burden occurred in this age group. Most of the disease burden for continuous risks occurred in those with only moderately raised levels, not among those with levels above commonly used cut-points, such as those with hypertension or obesity. Of all disease burden attributable to being underweight during childhood, 55% occurred among children 1–3 standard deviations below the reference population median, and the remainder occurred among severely malnourished children, who were three or more standard deviations below median. CONCLUSIONS: Many major global risks are widely spread in a population, rather than restricted to a minority. Population-based strategies that seek to shift the whole distribution of risk factors often have the potential to produce substantial reductions in disease burden
Search for Tensor, Vector, and Scalar Polarizations in the Stochastic Gravitational-Wave Background
The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω0T<5.58×10-8, Ω0V<6.35×10-8, and Ω0S<1.08×10-7 at a reference frequency f0=25 Hz. © 2018 American Physical Society
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