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Le choix d'un debit minimal a maintenir dans le lit d'un cours d'eau est une question particulierement repandue qui a conduit a l'elaboration de modeles predictifs comme la methode des microhabitats. Nous utilisons ici un modele d'habitat statistique pour estimer les impacts de la gestion des debits. Ce nouveau modele est base sur le couplage de modeles hydrauliques statistiques qui predisent les distributions en frequence des variables hydrauliques dans un cours d'eau avec des modeles de preference multivaries qui estiment des indices de densite piscicole en fonction de l'hydraulique. Nous appliquons le modele d'habitat statistique sur differents troncons du Rhone court-circuites par les amenagements hydrauliques. Nous exprimons les predictions a l'echelle du peuplement a l'aide d'indices piscicoles multivaries. Ces simulations nous permettent de comparer les impacts de l'augmentation des debits reserves predits sur les differents troncons, nous amenent a relativiser la notion de debit reserve optimal et a insister sur l'importance du choix des objectifs de gestion. Certains troncons du Rhone presentent un fort interet pour la diversite piscicole du fleuve amenage quel que soit l'objectif de gestion choisi.

In the sol-gel technology, either for bulk or thin films, the stability in time of the solutions is a major factor to control. An evolution of the solution may influence strongly the properties of the elaborated material (thickness, cracks, refractive index, conductivity, etc.), and cases have been reported where solutions had to be stored in a dry and cold place to prevent any hydrolysis-condensation reaction, and so any consequent gelation.

The influence of elaboration parameters during the sol-gel process is studied for tin oxide films deposition. The Dip Coating Sol-Gel route can be divided into three elaboration stages: the pulling phase and the drying and densification steps. During the pulling phase, the relative humidity ratio and the withdrawal speed are found to influence the film morphology and the film thickness respectively. Then, we show how a correct control of the sample drying is able to eliminate cracks. The densification step (temperature and duration), leading to the final network, is considered in details, and resulting effects on physical properties are presented: crytallinity, optical behaviour, atomic density, stoichiometry, electrical conductivity etc... We show through these results the specificity of the tin oxide elaborated with our procedure

The antimony doping in SnO2 thin films prepared by the sol-gel dip-coating method has been studied using two characterization techniques. In order to determine the actual doping level directly in the deposited layers, X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) have been used. We found that this doping level is systematically lower than expected from the starting solutions composition, and that two oxidation states are present: Sb3+ and Sb5+. As the antimony content increases, there is a competition between Sb5+ and Sb3+ species. The SnO2: Sb thin films have also been observed by transmission electron microscopy (TEM), showing that the measured mean size of crystallites decreases as the Sb content increases in the oxide. No precipitates of either Sn or Sb oxides (other than SnO2) could be detected.

International audience; PURPOSE:Aortic stiffness is a functional and structural consequence of ageing and arteriosclerosis. Regional arterial stiffness can be easily evaluated using pOpmetre(®) (Axelife SAS, France). This new technique assesses the pulse wave transit time (TT) between the finger (TTf) and the toe (TTt). Based on height chart, regional pulse wave velocity (PWV) between the toe and the finger can be estimated (PWVtf). pOpscore(®) index is also calculated as the ratio between PWVtoe and PWVfinger and can be considered as a peripheral vascular stiffness index. The aim of the study was to evaluate the relationship between pOpmetre(®) indices and the presence of carotid plaques in a population with cardiovascular risk factors.METHODS:In 77 consecutive patients recruited for a vascular screening for atherosclerosis (46 men aged 54 ± 2 years; 31 women aged 49 ± 3 years; ns), the difference between TTt and TTf (called Dt-f), the regional pulse wave velocity between the toe and the finger (PWVtf = constant × height/Dt-fm/s) and pOpscore(®) were measured by pOpmetre(®). Presence of carotid plaques was assessed using ultrasound imaging. The local aortic stiffness (AoStiff) was evaluated by the Physioflow(®) system.RESULTS:No difference was found between patients with or without carotid plaques (n=25 versus 52) for Ankle-Brachial Pressure Index (ABPI: 1.15 ± 0.04 versus 1.12 ± 0.03), nor for diastolic or systolic blood pressure (87 ± 3 versus 82 ± 2; 137 ± 3 versus 132 ± 2 mmHg). The first group was older than the second (59 ± 2 versus 49 ± 2 years, P

Two-level fluctuations of the magnetization state of pseudo-spin-valve pillars $\mathrm{C}\mathrm{o}(10\text{ }\mathrm{n}\mathrm{m})/\phantom{\rule{0ex}{0ex}}\mathrm{C}\mathrm{u}(10\text{ }\mathrm{n}\mathrm{m})/\mathrm{C}\mathrm{o}(30\text{ }\mathrm{n}\mathrm{m})$ embedded in electrodeposited nanowires ($\ensuremath{\sim}40\text{ }\text{ }\mathrm{n}\mathrm{m}$ in diameter, 6000 nm in length) are triggered by spin-polarized currents of ${10}^{7}\text{ }\mathrm{A}/{\mathrm{c}\mathrm{m}}^{2}$ at room temperature. The statistical properties of the residence times in the parallel and antiparallel magnetization states reveal two effects with qualitatively different dependences on current intensity. The current appears to have the effect of a field determined as the bias field required to equalize these times. The bias field changes sign when the current polarity is reversed. At this field, the effect of a current density of ${10}^{7}\text{ }\mathrm{A}/{\mathrm{c}\mathrm{m}}^{2}$ is to lower the mean time for switching down to the microsecond range. This effect is independent of the sign of the current and is interpreted in terms of an effective temperature for the magnetization.

We study the influence of a DC bias voltage V on quantum interference corrections to the measured differential conductance in metallic mesoscopic wires and rings. The amplitude of both universal conductance fluctuations (UCF) and Aharonov-Bohm effect (ABE) is enhanced several times for voltages larger than the Thouless energy. The enhancement persists even in the presence of inelastic electron-electron scattering up to V ~ 1 mV. For larger voltages electron-phonon collisions lead to the amplitude decaying as a power law for the UCF and exponentially for the ABE. We obtain good agreement of the experimental data with a model which takes into account the decrease of the electron phase-coherence length due to electron-electron and electron-phonon scattering., New title, refined analysis. 7 pages, 3 figures, to be published in Europhysics Letters

The aim of the study reported here was to set up a method for echocardiography (EC) and abdominal sonography and to obtain EC reference values for left ventricular (LV) morphology and function and sonographic abdominal aortic morphology, function, and flow values in conscious, unsedated Gottingen minipigs.Applying a standardized investigation procedure, the following parameters were measured by use of M-mode EC, color-coded Doppler imaging, and B-mode sonography, or were calculated, in 58 female minipigs: LV end-diastolic and end-systolic diameter, interventricular septum thickness, LV caudal wall thickness, LV end-diastolic volume and end-systolic volume, fractional shortening, ejection fraction, and percentage of thickening of interventricular septum and LV caudal wall. In addition, morphology, pulsatility, flow values, and flow patterns in the abdominal aorta were recorded or calculated during abdominal sonography and color-coded Doppler imaging.Variable EC values were obtained due to individual variations of motor activity. Variation could be reduced by accustoming the animals to a standardized investigation procedure. Reference values could be obtained for EC, partially indicating clear correlation with body weight. Color-coded Doppler and Doppler spectra did not indicate flow disturbances in large arterial abdominal vessels.Results indicate that handling during EC and sonography can cause discomfort in unsedated minipigs that may interfere with recording of valid reference values for functional cardiac parameters in young animals. Accustoming the animals to a standardized investigation procedure reduces stress to a satisfactory level and enables data recording. Thus the minipig is considered suitable for assessment of cardiovascular parameters in experimental or toxicologic studies.

Osteosarcoma-derived osteoblastic cells were exposed to 1,25 dihydroxyvitamin D3 (1,25(OH)2D3) either to 0.001-1,000 nmol.l-1 for 4 days or to 10 nmol.-1 for 1-21 days. Between 0.01 and 10 nmol.l-1, a dose-dependent increase in alkaline phosphatase (AP) activity was found, which rose to a maximum level at 10 nmol.l-1 (+55%). At higher doses (100 and 1,000 nmol.l-1), 1,25(OH)2D3 induced a decrease in AP activity of 40%. After 1 day at 10 nmol.l-1 a slight increase in AP activity was noted (+20%) which augmented with the duration of exposure. This stimulatory effect was highest after 8 days (+130%). In contrast, after 15 and 21 days, AP activity decreased by 30%. Under 1,25(OH)2D3, microtubules were observed mainly in the perinuclear region.

Osteosarcoma-derived osteoblastic cells were exposed to 1,25 dihydroxyvitamin D3 (1,25(OH)2D3) either to 0.001-1,000 nmol.l-1 for 4 days or to 10 nmol.-1 for 1-21 days. Between 0.01 and 10 nmol.l-1, a dose-dependent increase in alkaline phosphatase (AP) activity was found, which rose to a maximum level at 10 nmol.l-1 (+55%). At higher doses (100 and 1,000 nmol.l-1), 1,25(OH)2D3 induced a decrease in AP activity of 40%. After 1 day at 10 nmol.l-1 a slight increase in AP activity was noted (+20%) which augmented with the duration of exposure. This stimulatory effect was highest after 8 days (+130%). In contrast, after 15 and 21 days, AP activity decreased by 30%. Under 1,25(OH)2D3, microtubules were observed mainly in the perinuclear region.

An exact design of switched-capacitor bandpass filters is presented. This new technique is based on the distributed circuit theory with a suitable bandpass transformation. The theoretical aspects of this method are given as well as the simulated results using a switched-capacitor circuit-analysis program.