94 research outputs found
On the multiplicity of the O-star Cyg OB2 #8A and its contribution to the gamma-ray source 3EG J2033+4118
We present the results of an intensive spectroscopic campaign in the optical
waveband revealing that Cyg OB2 #8A is an O6 + O5.5 binary system with a period
of about 21.9 d. Cyg OB2 #8A is a bright X-ray source, as well as a non-thermal
radio emitter. We discuss the binarity of this star in the framework of a
campaign devoted to the study of non-thermal emitters, from the radio waveband
to gamma-rays. In this context, we attribute the non-thermal radio emission
from this star to a population of relativistic electrons, accelerated by the
shock of the wind-wind collision. These relativistic electrons could also be
responsible for a putative gamma-ray emission through inverse Compton
scattering of photospheric UV photons, thus contributing to the yet
unidentified EGRET source 3EG J2033+4118.Comment: 8 pages, 4 figures, conference on "The Multiwavelength Approach to
Gamma-Ray Sources", to appear in Ap&S
Ratios of anti-factor Xa to antithrombin activities of heparins as determined in recalcified human plasma
Anti-factor Xa and anti-thrombin activities of unfractionated (UF) and low molecular weight (LMW) heparins have been measured in human plasma and with purified human antithrombin III (ATIII) in the absence and presence of 1-5 mM calcium. The anti-factor Xa and antithrombin activities were measured directly, by assessing the heparin-dependent pseudo-first order rate constants of inactivation of human factor Xa or thrombin. These activities were studied with the 4th International Standard for UF heparin, the 1st International Standard for LMW heparin, CY216, enoxaparin, CY222, and the synthetic pentasaccharide. In plasma, calcium equally well increased the specific anti-factor Xa catalytic activities as compared to purified ATIII. That is, 1.5 mM calcium stimulated the UF standard heparin-catalysed inactivation of factor Xa 2.1-2.4 times. In the presence of the LMW heparins the effect of calcium was smaller (1.3-1.7 times), and in plasma there was no effect of calcium on the pentasaccharide-catalysed inactivation of factor Xa. Thus, the largest effects of calcium in the inactivation reaction of factor Xa is seen with UF standard heparin. Calcium reduced the anti-thrombin activities of all the heparin preparations studied about 1.5 times when purified ATIII was used, although in plasma this effect was less clear. Consequently, in the presence of 1.5 mM calcium the ratio of the anti-factor Xa to the anti-thrombin activities of UF standard heparin approximated those of the LMW heparins. The only exception was CY222, which under all conditions retained anti-factor Xa/anti-thrombin ratios significantly higher than those of UF standard heparin
International collaborative project to compare and track the nutritional composition of fast foods
Background: Chronic diseases are the leading cause of premature death and disability in the world with
over-nutrition a primary cause of diet-related ill health. Excess quantities of energy, saturated fat, sugar and salt
derived from fast foods contribute importantly to this disease burden. Our objective is to collate and compare
nutrient composition data for fast foods as a means of supporting improvements in product formulation.
METHODS/DESIGN: Surveys of fast foods will be done in each participating country each year. Information on the
nutrient composition for each product will be sought either through direct chemical analysis, from fast food
companies, in-store materials or from company websites. Foods will be categorized into major groups for the
primary analyses which will compare mean levels of saturated fat, sugar, sodium, energy and serving size at
baseline and over time. Countries currently involved include Australia, New Zealand, France, UK, USA, India, Spain,
China and Canada, with more anticipated to follow.
DISCUSSION: This collaborative approach to the collation and sharing of data will enable low-cost tracking of fast
food composition around the world. This project represents a significant step forward in the objective and
transparent monitoring of industry and government commitments to improve the quality of fast foods.E Dunford is supported by a Sydney Medical School Foundation scholarship
and B Neal by an Australian Research Council Future Fellowship.http://www.biomedcentral.com/1471-2458/12/559am201
Structure of the solar photosphere studied from the radiation hydrodynamics code ANTARES
Risk perception and trust: Challenges for facility siting
The authors maintain that, by granting legitimacy to different notions of fairness and building on common values such as responsibility, it is possible to design siting procedures that promote social cohesion, trust and a sense of fair play
Observations on the cytology of Bipes (Amphisbaenia) with special reference to its lampbrush chromosomes
Ribosomal gene amplification in multinucleate oocytes of the egg brooding hylid frog Flectonotus pygmaeus
Multiple ribosomal gene sites revealed by in situ hybridization of Xenopus rDNA to Tritums lampbrush chromosomes
The arrangement and transcription of ?middle repetitive? DNA sequences on lampbrush chromosomes of Triturus
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