2,576 research outputs found
Installation and commissioning of the ATLAS LAr Read-Out electronics
International audienceThe cryostats of the ATLAS LAr calorimeter system are installed in the ATLAS cavern since several years. Following this, an effort to install and commission the front end read-out electronics (infrastructure, crates, boards) has been ongoing and is finished now, in time for the cavern closure. Following cautious procedures and with continuous testing-campaigns of the electronics at each step of the installation advancement, the result is a fully commissioned calorimeter with its readout and a small number of non-functional channels. A total of only 0.017% of the read out channels is dead and 0.4% need special treatment for calibration. The presentation will give a general overview of the installation and refurbishment campaign of the ATLAS LAr calorimeter electronics and show results of the calibration runs that were taken continuously during the various phases of commissioning. Different problems observed and addressed will be discussed. It will describe noise studies that have been performed and shortly review the solutions implemented to reduce noise. The excellent stability of the calorimeter readout will be demonstrated by showing results from pedestal and pulse height studies
Environmental factors and effects on breeding performances and housing in small laboratory rodents: A technical report
Based on their professional experience in large scale production of laboratory rodents, the authors report on some documented cases showing the effects of environmental factors on reproductive performances of the rodent strains they produce. Beyond continuation of the effect of a Simple environmental factor (temperature, light) the reported cases show that environmental effects must not be systematically generalized to several strains or, even less, to several species.Moreover, the incidence of associated (complex) factors, which cannot be evaluated without the opportunity of having a control sample must be emphasized. This last point is of major importance when comparing results coming from different laboratories although the maintain environmental factors are a priori identical
Integrable motion of a vortex dipole in an axisymmetric flow
The evolution of a self-propelling vortex dipole, embedded in an external nondivergent flow with constant potential vorticity, is studied in an equivalent-barotropic model commonly used in geophysical, astrophysical and plasma studies. In addition to the conservation of the Hamiltonian for an arbitrary point vortex dipole, it is found that the angular momentum is also conserved when the external flow is axisymmetric. This reduces the original four degrees of freedom to only two, so that the solution is expressed in quadratures. In particular, the scattering of antisymmetric dipoles approaching from the infinity is analyzed in the presence of an axisymmetric oceanic flow typical for the vicinity of isolated seamounts
The Equation of State and the Hugoniot of Laser Shock-Compressed Deuterium
The equation of state and the shock Hugoniot of deuterium are calculated
using a first-principles approach, for the conditions of the recent shock
experiments. We use density functional theory within a classical mapping of the
quantum fluids [ Phys. Rev. Letters, {\bf 84}, 959 (2000) ]. The calculated
Hugoniot is close to the Path-Integral Monte Carlo (PIMC) result. We also
consider the {\it quasi-equilibrium} two-temperature case where the Deuterons
are hotter than the electrons; the resulting quasi-equilibrium Hugoniot mimics
the laser-shock data. The increased compressibility arises from hot
pairs occuring close to the zero of the electron chemical potential.Comment: Four pages; One Revtex manuscript, two postscipt figures; submitted
to PR
Molecular genetics of congenital atrial septal defects
Congenital heart defects (CHD) are the most common developmental errors in humans, affecting 8 out of 1,000 newborns. Clinical diagnosis and treatment of CHD has dramatically improved in the last decades. Hence, the majority of CHD patients are now reaching reproductive age. While the risk of familial recurrence has been evaluated in various population studies, little is known about the genetic pathogenesis of CHD. In recent years significant progress has been made in uncovering genetic processes during cardiac development. Data from human genetic studies in CHD patients indicate that the genetic aetiology was presumably underestimated in the past. Inherited mutations in genes encoding cardiac transcription factors and sarcomeric proteins were found as an underlying cause for familial recurrence of non-syndromic CHD in humans, in particular cardiac septal defects. Notably, the cardiac phenotypes most frequently seen in mutation carriers are ostium secundum atrial septal defects (ASDII). This review outlines experimental approaches employed for the detection of CHD-related genes in humans and summarizes recent findings in molecular genetics of congenital cardiac septal defects with an emphasis on ASDII
Efficacy of targeting bone-specific GIP receptor in ovariectomy-induced bone loss
Glucose-dependent insulinotropic polypeptide (GIP) has been recognized in the last decade as an important contributor of bone remodeling and is necessary for optimal bone quality. However, GIP receptors are expressed in several tissues in the body and little is known about the direct versus indirect effects of GIP on bone remodeling and quality. The aims of the present study were to validate two new GIP analogues, called [D-Ala2]-GIP-Tag and [D-Ala2]-GIP1-30, that specifically target either bone or whole body GIP receptors, respectively; and to ascertain the beneficial effects of GIP therapy on bone in a mouse model of ovariectomy-induced bone loss. Both GIP analogues exhibited similar binding capacities at the GIP receptor and intracellular responses as full-length GIP1-42. Furthermore, only [D-Ala2]-GIP-Tag, but not [D-Ala2]-GIP1-30, was undoubtedly found exclusively in the bone matrix and released at acidic pH. In ovariectomized animals, [D-Ala2]-GIP1-30 but not [D-Ala2]-GIP-Tag ameliorated bone stiffness at the same magnitude than alendronate treatment. Only [D-Ala2]-GIP1-30 treatment led to significant ameliorations in cortical microarchitecture. Although alendronate treatment increased the hardness of the bone matrix and the type B carbonate substitution in the hydroxyapatite crystals, none of the GIP analogues modified bone matrix composition. Interestingly, in ovariectomy-induced bone loss, [D-Ala²]-GIP-Tag failed to alter bone strength, microarchitecture and bone matrix composition. Overall, this study shows that the use of a GIP analogue that target whole body GIP receptors might be useful to improve bone strength in ovariectomized animals
Dedicated and industrial robotic arms used as force feedback telerobots at the AREVA-La Hague recycling plant
ISBN: 978-1-4244-6635-1/10International audienceCEA LIST and AREVA have been developing remote operations devices, also called telerobotics for 15 years. These tools were designed for interventions in the AREVA nuclear spent fuel facilities hot cells. From these 15 years of joint research and development, several technological bricks have been industrialized and used at the AREVA La Hague facilities. This article presents some of these bricks and their industrial developments. The “TAO2000” CEA LIST telerobotics generic software controller will be first discussed. This controller has been used to teleoperate dedicated slave arms like the MT200 TAO (an evolution of the conventional wall-transmission mechanical telemanipulator (MSM)) as well as industrial robotic arms like the Stäubli RX robots. Both the MT200 TAO and Stäubli RX TAO telerobotics systems provide force-feedback and are now ready to be used as telemaintenance tools at the AREVA La Hague facilities. Two recent maintenance operations using these tools will be detailed at the end of this pape
Cosmic-ray propagation properties for an origin in SNRs
We have studied the impact of cosmic-ray acceleration in SNR on the spectra
of cosmic-ray nuclei in the Galaxy using a series expansion of the propagation
equation, which allows us to use analytical solutions for part of the problem
and an efficient numerical treatment of the remaining equations and thus
accurately describes the cosmic-ray propagation on small scales around their
sources in three spatial dimensions and time. We found strong variations of the
cosmic-ray nuclei flux by typically 20% with occasional spikes of much higher
amplitude, but only minor changes in the spectral distribution. The locally
measured spectra of primary cosmic rays fit well into the obtained range of
possible spectra. We further showed that the spectra of the secondary element
Boron show almost no variations, so that the above findings also imply
significant fluctuations of the Boron-to-Carbon ratio. Therefore the commonly
used method of determining CR propagation parameters by fitting
secondary-to-primary ratios appears flawed on account of the variations that
these ratios would show throughout the Galaxy.Comment: Accepted for publication in Ap
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Moderate Champagne consumption promotes an acute improvement in acute endothelial-independent vascular function in healthy human volunteers
Epidemiological studies have suggested an inverse correlation between red wine consumption and the incidence of CVD. However, Champagne wine has not been fully investigated for its cardioprotective potential. In order to assess whether acute and moderate Champagne wine consumption is capable of modulating vascular function, we performed a randomised, placebo-controlled, cross-over intervention trial. We show that consumption of Champagne wine, but not a control matched for alcohol, carbohydrate and fruit-derived acid content, induced an acute change in endothelium-independent vasodilatation at 4 and 8 h post-consumption. Although both Champagne wine and the control also induced an increase in endothelium-dependent vascular reactivity at 4 h, there was no significant difference between the vascular effects induced by Champagne or the control at any time point. These effects were accompanied by an acute decrease in the concentration of matrix metalloproteinase (MMP-9), a significant decrease in plasma levels of oxidising species and an increase in urinary excretion of a number of phenolic metabolites. In particular, the mean total excretion of hippuric acid, protocatechuic acid and isoferulic acid were all significantly greater following the Champagne wine intervention compared with the control intervention. Our data suggest that a daily moderate consumption of Champagne wine may improve vascular performance via the delivery of phenolic constituents capable of improving NO bioavailability and reducing matrix metalloproteinase activity
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