Application of a Modified Statistical Segmentation Method to Timber Machine Strength Grading

In this paper, a new method for deriving grading rules is given. This method is based on the multiple regression and discrimination techniques by binary prediction trees, which are of high interest for classification purposes. A modification to the existing practice that tends to predict the bending modulus of rupture (MOR) is presented. This method consists in creating a nominal variable, the "optimal strength class value," which contains the information necessary to enter into a strength class system, i.e., the density, the bending modulus of elasticity (MOE), and the MOR. A comparison between a regression technique aimed at predicting the MOR and a discrimination technique aimed at predicting the optimal strength class assignment illustrates the innovative aspect of this method

Restoration genetics of north-west European saltmarshes: A multi-scale analysis of population genetic structure in Puccinellia maritima and Triglochin maritima

Increasing human pressure combined with sea level rise and increased storminess is threatening coastal ecosystems around the world. Among these ecosystems, saltmarshes are particularly endangered due to their position in temperate areas with low wave action where human density is often high (e.g. estuaries). Around the UK, centuries of land reclamation have led to a substantial decrease of the area of saltmarsh. Over the past decades, restoration schemes have been implemented in numerous coastal locations in an attempt to counteract this loss. Such schemes involve allowing sea water to inundate a previously embanked area and letting the vegetation develop naturally, thereby reverting to saltmarsh through natural colonisation. However, surveys of restored areas that have looked at the recovery of plant species diversity or functional characteristics often show that restored saltmarshes do not reach the state of a natural saltmarsh ecosystem. While there is much data at the species level, recovery of plant intra-specific diversity (genetic diversity) has not been assessed in restored saltmarsh although this component of biodiversity is receiving increasing attention for its effect on ecosystem function. This thesis represents the first attempt to (1) characterize the nation-wide genetic structure of two important north-west European saltmarsh plant species, the common saltmarsh grass (Puccinellia maritima) and the sea arrowgrass (Triglochin maritima) and (2) compare levels of genetic diversity and structure between restored and natural ecosystems. Microsatellite molecular markers were developed for both species. Using innovative methods to analyse the genetic data obtained for these two polyploid species, this thesis highlights that genetic diversity at the national scale is organised regionally for both species, although gene-flow is still restricted between populations within the same region. Gene-flow between populations is determined by different processes depending on the species. While coastal processes mainly influence gene dispersal in P. maritima, overland routes of dispersal are involved for T. maritima. These differences are believed to be due to differences in dispersal ecology between the two species. Although gene-flow exists between distant saltmarshes, the genetic analysis of P. maritima and T. maritima colonists arriving on restored sites highlighted their local origin and reaffirmed that it is preferable to restore saltmarsh where a nearby natural saltmarsh can act as a source of colonists. A multiple paired-site comparison identified similar genetic diversity between restored and natural saltmarshes indicating that restoration of local genetic diversity is rapid for both species. A single site comparison at Skinflats in the Forth estuary compared fine-scale spatial genetic structure between the restored and natural saltmarsh. Interestingly, no structure was detected for T. maritima either in restored or natural saltmarsh. In contrast, a strong genetic structure organised along the elevation gradient was observed in the natural saltmarsh for P. maritima but was absent in the restored saltmarsh. The origin of this structure is not clear but could be due to restricted gene-flow between individuals from different elevations due to strong post-zygotic selection, as suggested in previous work. In any case, this lack of structure in the restored saltmarsh indicates that genetic recovery is incomplete in this respect for P. maritima. This thesis introduces the growing field of restoration genetics to saltmarsh ecology and identifies the principal population genetic trends in two of the species dominating the vegetation of north-west European saltmarshes community. The information given here will be useful for restoration practitioners and provides a strong foundation for future work characterizing the importance of genetic diversity for saltmarsh function

Proteomic Analysis of Signalling Pathway Deregulation in Dystrophic Dog Muscle

International audienc

Acclimatation d'une biomasse anaérobie à un effluent de fabrication d'une pâte à papier à concentration élevée en composés soufrés

L'effluent de fabrication à partir de bois de résineux d'une Pâte Chimico-Thermo-Mécanique (CTMP) contenant des dérivés soufrés organiques et des sulfates, est très difficilement épuré par voie anaérobie. La présente étude montre qu'il est indispensable d'acclimater la biomasse à de fortes concentrations en soufre dans l'effluent. Ceci est réalisé en alimentant un réacteur à biomasse fixée (pilote de laboratoire), en fonctionnement continu, par des mélanges d'un effluent de distillerie et de l'effluent CTMP, dans lesquels la proportion du second est augmentée par paliers successifs jusqu'à 100 %.On peut alors finalement obtenir une épuration convenable de l'effluent CTMP à des teneurs en soufre jusqu'à 500 mg/l (pourvu que le rapport DCO/S soit supérieur à 10 environ).Anaerobic treatment of wastewater from chemico-thermomechanical pulping (CTMP) of softwoods was inhibited by sulphur containing compounds. Distillery skips are characterized by a high sulphur content and a more appropriate COD/sulphur ratio than CTMP wastewater. Using CTMP wastewater together with distiliery stops during initial starting up resulted in successful acclimatation of microorganisms to significant sulphate contents.Provided the COD/Sulphur was aboue 10 reasonably good treatment efficiency was obtained with CTMP wastewater containing to 500 mg total sulphur per liter

Perception audiovisuelle de la parole chez le sourd postlingual implanté cochléaire et le sujet normo-entendant : étude longitudinale psychophysique et neurofonctionnelle

Nos travaux ont consisté à étudier les mécanismes perceptifs et neuronaux impliqués lors de la perception audiovisuelle de la parole chez des patients sourds postlinguaux implantés cochléaires et des sujets contrôles normo-entendants. Dans ce but nous avons testé les performances audiovisuelles des patients implantés au cours de suivis longitudinaux en comportemental et en tomographie par émission de positrons, ainsi qu'au travers d'un paradigme de parole audiovisuelle incongruente (McGurk). Pour comparaison nous avons systématiquement testé des sujets contrôles dans les mêmes conditions. Nous avons également testé ces derniers en condition de lecture labiale puis en utilisant des dégradations de la parole auditive et audiovisuelle par du bruit blanc et par une simulation acoustique d'implant cochléaire. L'ensemble de ces études concorde pour indiquer, à la suite de l'implantation cochléaire, une réorganisation rapide des réseaux corticaux multisensoriels impliqués dans l'intégration audiovisuelle de la parole, aboutissant à une combinaison optimale des indices perceptifs audiovisuelsOur present work consisted in studying perceptual and neuronal mechanisms involved during audiovisual speech perception in postlingually deaf cochlear-implant patients and normally-hearing controls. With this aim in view we tested audiovisual performance for implanted patients during longitudinal follow-ups using behavioral methods and positron emission tomography neuroimagery, as well as incongruent audiovisual speech (McGurk paradigm). In order to achieve appropriate comparisons, control subjects were tested in identical conditions. Moreover they were tested in a speechreading condition and with auditory and audiovisual speech degraded through white-noise masks and cochlear-implant computer simulations. Results from these studies agree to point out, following cochlear implantation, a fast reorganization of multisensory cortical networks involved in audiovisual speech integration, leading to an optimal combination of audiovisual perceptual cue

La diode Schottky en diamant : le présent et le futur

International audienceDes diodes Schottky en diamant avec une structure pseudo-verticales montrant une densité de courant de 10^3A/cm2 (à 6V) avec un champ de claquage supérieur à 7.7MV/cm ont été réalisées. Ces diodes ont été obtenues par croissance homoépitaxiale du diamant avec le zirconium comme métal de contact Schottky. Ces résultats ont permis d'avoir le record mondial actuel du facteur de Baliga pour le diamant avec 244MV/cm^2. Ces travaux montrent que les potentialités du diamant ne sont pas uniquement théoriques. La maitrise actuelle des interfaces et de la croissance permettent d'imaginer des composants de puissance performant en poussant le diamant dans ses retranchements

Design and characterization of a signal insulation coreless transformer integrated in a CMOS gate driver chip

International audienceWith the development of multi-level, multiphase or network converters requiring the implementation of numerous distinct power transistor gate drivers, the control signal insulation is becoming more and more important in power converters. This paper presents an isolation technique based on a coreless transformer integrated in a CMOS silicon die together with the gate driver and other required functions. The associated demodulation circuit will also be presented, as the control signal must be modulated at a high frequency through the coreless transformer. The chosen design methodology will be explained and experimental results will be shown in order to validate the functionality

Diamond power devices: state of the art, modelling, figures of merit and future perspective

Abstract: With its remarkable electro-thermal properties such as the highest known thermal conductivity (~22 W cm−1∙K−1 at RT of any material, high hole mobility (>2000 cm2 V−1 s−1), high critical electric field (>10 MV cm−1), and large band gap (5.47 eV), diamond has overwhelming advantages over silicon and other wide bandgap semiconductors (WBGs) for ultra-high-voltage and high-temperature (HT) applications (>3 kV and >450 K, respectively). However, despite their tremendous potential, fabricated devices based on this material have not yet delivered the expected high performance. The main reason behind this is the absence of shallow donor and acceptor species. The second reason is the lack of consistent physical models and design approaches specific to diamond-based devices that could significantly accelerate their development. The third reason is that the best performances of diamond devices are expected only when the highest electric field in reverse bias can be achieved, something that has not been widely obtained yet. In this context, HT operation and unique device structures based on the two-dimensional hole gas (2DHG) formation represent two alternatives that could alleviate the issue of the incomplete ionization of dopant species. Nevertheless, ultra-HT operations and device parallelization could result in severe thermal management issues and affect the overall stability and long-term reliability. In addition, problems connected to the reproducibility and long-term stability of 2DHG-based devices still need to be resolved. This review paper aims at addressing these issues by providing the power device research community with a detailed set of physical models, device designs and challenges associated with all the aspects of the diamond power device value chain, from the definition of figures of merit, the material growth and processing conditions, to packaging solutions and targeted applications. Finally, the paper will conclude with suggestions on how to design power converters with diamond devices and will provide the roadmap of diamond device development for power electronics