594 research outputs found
Arterial distensibility in adolescents: the influence of adiposity, the metabolic syndrome, and classic risk factors.
BACKGROUND: Atherosclerosis develops from childhood, but the determinants of this preclinical stage remain uncertain. We examined the relations of classic coronary risk factors, adiposity and its associated metabolic disturbances, to arterial distensibility (a marker of early arterial disease) in 13- to 15-year-olds, some of whom had previously been studied at ages 9 to 11 years. METHODS AND RESULTS: Brachial artery distensibility was measured by a noninvasive ultrasound technique in 471 British children in whom measures of adiposity, blood pressure, fasting blood lipids, and insulin had been made. All adiposity measures showed strong graded inverse relationships with distensibility. Inverse associations with distensibility were also observed for insulin resistance (homeostasis model assessment), diastolic pressure, C-reactive protein, and the number of metabolic syndrome components present, which had a graded relation to distensibility. Total and LDL cholesterol levels were also inversely related to distensibility, but less strongly than adiposity; homocysteine had no relation to distensibility. Although the relations of total and LDL cholesterol and diastolic pressure to distensibility had been present at 9 to 11 years of age, those of adiposity and insulin resistance were only apparent at 13 to 15 years. CONCLUSIONS: Adiposity and its metabolic consequences are associated with adverse changes in the arterial wall by the teenage years. The graded relation with increasing adiposity was stronger than that for cholesterol and was seen at body mass index levels well below those considered to represent "obesity." This emphasizes the importance of population-based strategies to control adiposity and its metabolic consequences in the young
Precision spectroscopy of pionic 1s states of Sn nuclei and evidence for partial restoration of chiral symmetry in the nuclear medium
Deeply bound 1s states of in Sn were preferentially
observed using the Sn(,He) pion-transfer reaction under the recoil-free
condition. The 1s binding energies and widths were precisely determined, and
were used to deduce the isovector parameter of the s-wave pion-nucleus
potential to be . The observed enhancement
of over the free value ()
indicates a reduction of the chiral order parameter, , at the normal nuclear density, .Comment: 4 pages including 3 postscript figures, RevTeX 4 with multirow.sty,
submitted to Physical Review Letter
Pionic Atom Spectroscopy in the (d,3He) reaction at finite angles
We study the formation of deeply bound pionic atoms in the (d,3He) reactions
theoretically and show the energy spectra of the emitted 3He at finite angles,
which are expected to be observed experimentally. We find that the different
combinations of the pion-bound and neutron-hole states dominate the spectra at
different scattering angles because of the matching condition of the reaction.
We conclude that the observation of the (d,3He) reaction at finite angles will
provide the systematic information of the pionic bound states in each nucleus
and will help to develop the study of the pion properties and the partial
restoration of chiral symmetry in nuclei.Comment: 7 pages, 4 figures, 1 tabl
Breit type equation for mesonic atoms
The finite size effects and relativistic corrections in pionic and kaonic
hydrogen are evaluated by generalizing the Breit equation for a spin-0 -
spin-1/2 amplitude with the inclusion of the hadron electromagnetic form
factors. The agreement of the relativistic corrections to the energies of the
mesonic atoms with other methods used to evaluate them is not exact, but
reasonably good. The precision values of the energy shifts due to the strong
interaction, extracted from data, are however subject to the hadronic form
factor uncertainties.Comment: 11 pages Late
Complete breeding failures in ivory gull following unusual rainy storms in North Greenland
Natural catastrophic events such as heavy rainfall and windstorms may induce drastic decreases in breeding success of animal populations. We report the impacts of summer rainfalls on the reproductive success of ivory gull (Pagophila eburnea) in north-east Greenland. On two occasions, at Amdrup Land in July 2009 and at Station Nord in July 2011, we observed massive ivory gull breeding failures following violent rainfall and windstorms that hit the colonies. In each colony, all of the breeding birds abandoned their eggs or chicks during the storm. Juvenile mortality was close to 100% at Amdrup Land in 2009 and 100% at Station Nord in 2011. Our results show that strong winds associated with heavy rain directly affected the reproductive success of some Arctic bird species. Such extreme weather events may become more common with climate change and represent a new potential factor affecting ivory gull breeding success in the High Arctic
Changes in trabecular bone, hematopoiesis and bone marrow vessels in aplastic anemia, primary osteoporosis, and old age
Retrospective histologic analyses of bone biopsies and of post mortem samples from normal persons of different age groups, and of bone biopsies of age- and sex-matched groups of patients with primary osteoporosis and aplastic anemia show characteristic age dependent as well as pathologic changes including atrophy of osseous trabeculae and of hematopoiesis, and changes in the sinusoidal and arterial capillary compartments. These results indicate the possible role of a microvascular defect in the pathogenesis of osteoporosis and aplastic anemia
Fairness index in single and double star Networks
In wireless network, the communication works in half duplex mode and nodes can interfere together. In this context, fairness is not obvious. This paper will focus on fairness in the received packets by each node. Fairness is evaluated for static networks topologies called Single Star Network or Double Star Network. The fairness is quantified by its index. In this work, the evaluation of fairness index for double star network is given. Some value of this index are not possible for double star network topology. For example the index of one can only be possible if the double star network is simular to star network. Then the star networks are studied and some simulations are used to illustrate the way to get fairness in the network by controlling the flow rates
Light-Front Analysis of pi^{-} Mesons Produced in Mg - Mg Collisions at 4.3 a Gev/c
Light-front analysis of pi^{-} mesons in Mg-Mg collisions is carried out. The
phase space of secondary pions is naturally divided into two parts in one of
which the thermal equilibration assumption seems to be in a good agreement with
data. Corresponding temperatures are extracted and compared to the results of
other experiments. The experimental results have been compared with the
predictions of the Quark Gluon String Model (QGSM) and satisfactory agreement
between the experimental data and the model has been found.Comment: 14 pages with 7 postscript figures. accepted for publication in Nucl.
Phys.
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