Synthèse sur la réduction conjointe de bruit et d’écho pour lés systèmes mains-libres

In the context of modern telecommunications, hands-free systems allow to talk in a more natural way, without handling a telephone. This leads to new problems which were negligible in classical telephony: the superposition of energetic noise and echo on the speech signal. To solve these problems and to provide a sufficient speech quality, a joint reduction of these perturbations is needed. This paper presents a synthesis of solutions retained to achieve this reduction in the context of mono-channel and two-channel observations.     

Shape optimization of geotextile tubes for sandy beach protection

This paper describes how to tackle new challenging coastal engineering problems related to beach erosion with a shape optimization approach. The method modifies the shape of the sea bottom in order to reduce beach erosion effects. Global optimization is shown to be necessary as the related functionals have several local minima. We describe the physical model used, the proposed protection devices against beach erosion and real case applications. Copyright © 2007 John Wiley & Sons, Ltd.     

Relation between teachers' early expectations and students' later perceived competence in physical education classes: Autonomy-supportive climate as a moderator.

The purpose of this study was to explore whether, in naturalistic physical education classes, the relation between teachers' early expectations and students' later perceived competence was moderated by the extent to which the motivational climate created by the teachers was autonomy supportive. Using a 1-year longitudinal design, data were obtained from 421 students and 22 teachers from 10 French junior high schools. Multilevel analyses revealed that (a) teachers' early expectations were related to students' later perceived competence, particularly when these expectations were positive, and (b) this relation was stronger when the classroom motivational climate was low in autonomy support. Implications for future research and educational practices are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Production,in continuous enzymatic membrane reactor,of an anti-hypertensive hydrolysate from an industrial alfalfa white protein concentrate exhibiting ACE inhibitory and opioid activities

A few hydrolysates of food proteins were reported to exert an antihypertensive effect in vivo due to angiotensin I converting enzyme (ACE) inhibitory peptides or opioid peptides. An industrial alfalfa white protein concentrate (AWPC) hydrolysate, produced on a pilot plant scale, strongly inhibited ACE with an IC50 value of 8.8 μg/ml. Furthermore, the AWPC hydrolysate inhibited the spontaneous contraction of rabbit ileum in a dose-dependent and naloxone-blocked manner, indicating the presence of opioid peptides. The AWPC hydrolysate significantly lowered blood pressure of spontaneously hypertensive rats (SHR) more than 6 h after a single oral administration. The maximum reduction of systolic blood pressure (−29.9 ± 2.0 mmHg) was observed 4 h after an oral administration of 0.5 g/kg hydrolysate dosage. The minimal anti-hypertensive effect was observed for 0.1 g/kg dosage. The AWPC hydrolysate may then be particularly suitable as nutraceutical for functional food useful in the prevention of hypertension.     

Effects of heat-processing regime, pH, water activity and their interactions on the behaviour of Listeria monocytogenes in ground pork. Modelling the boundary of the growth/no-growth areas as a function of pH, water activity and temperature

The influence of four heat‐processing regimes and a storage phase on the behaviour of Listeria monocytogenes in ground pork was studied. The effects of pH and water activity (a_w) were also tested. During the heat process phase, a_w, the heat‐processing regime and its interactions with pH or a_w, had a significant effect on the behaviour of L. monocytogenes. During the storage phase, all parameters tested and their interactions had significant effects. Nevertheless, the area in which the growth of L. monocytogenes was observed at the end of the experiment was not influenced by the heat‐processing regime tested. On the contrary, pH, a_w and their interactions had significant effects on Listeria behaviour. The boundary of the growth area delimited by environmental conditions where growth was higher than 1.0 Log CFU g^?1 from those where growth was lower than this limit was correctly predicted by Augustin's model.     

Productivity loss in performance groups: People who see themselves as average do not engage in social loafing.

The authors predicted that individuals who see themselves as average (e.g., who have a generalized belief in being no better or worse than others) do not engage in social loafing, unlike those who see themselves as generally superior to others. As expected, study participants who felt uniquely superior expended less effort when working collectively than when working coactively on an easy task, but they actually worked harder collectively than coactively on a more challenging task. Such effects did not occur in participants who perceived themselves as average. Taken together, these findings provide further support for S. J. Karau and K. D. Williams's (see record 1994-33384-001) collective effort model. They also suggest that what people come to believe about the relation between the self and others is a crucial factor in collective work contexts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Combinatorial solid state chemistry by multitarget laser ablation: a way for the elaboration of new superconducting cuprates thin films?

Laser ablation by varying the number of consecutive laser pulses upon two targets, one superconducting YBa₂Cu₃O₇, the other insulating MCuO₂ (M=Sr, Ca), is used to build thin films of tuneable average compositions. Most of the samples are found to display high-T_c superconductivity with critical temperature generally higher than the 60 K of the ‘Cava phase’, the prototypic structure with two consecutive conducting CuO₂ planes and containing same types of atoms. The properties of the samples are not linearly dependent on the concentration of species coming from the insulating target. In addition, they depend not only on the ratio of the number of pulses on each target, but also on the number of consecutive pulses on each target. Thin films are characterized by temperature-dependent DC conductivity, X-ray diffraction, Castaing microprobe and infrared reflectivity spectroscopy. Present results suggest the robustness of high-T_c superconductivity, possibly related to a ‘Cava-phase-like’ skeleton.     

Molecular Guided Catalytic Hydrogenation by Micelle-Hosted Pd Nanoparticle in Supercritical CO2

Homogeneous dispersion of microemulsion containing palladium nanoparticles in scCO₂ is, for the first time, observed via sapphire window reactor and these particles show an unusual reluctance for double bond hydrogenation of citral aldehyde at hydrophobic end rather than hydrophilic end (high regioselectivity) owing to the unique micelle environment in supercritical carbon dioxide that guide a head-on attack of the molecule.