Gummel-Poon modeling of a New Super-Gain BJT and an innovative 600V AC switch

International audienceThis paper deals with the static electrical modeling of the super-gain BJT and the innovative 600V AC switch solution which it gives to. As power bipolar component, their modeling is based on the Gummel-Poon model which is widely accepted and used by researchers as well as circuit simulators like Pspice. All of the model parameters are extracted from device characterization data via extraction mathematical equations. The modeling of the super-gain BJT is mainly composed of two separate parts which is respectively the forward-biased modeling and the reverse-biased modeling. The characterization test bench is presented, than the extraction methods of respective parameter category are also introduced in this paper as well as the data processing method. The validation of the extracted model parameters will be done by comparing the SPICE simulation results with experimental ones under the same condition. The comparison result proves a good coherence between simulations and experimentations

Status of the BMV experiment

In this contribution we present the status of the BMV experiment whose goal is to measure the vacuum magnetic birefringence

High-fidelity promoter profiling reveals widespread alternative promoter usage and transposon-driven developmental gene expression

Many Eukaryotic genes possess multiple alternative promoters with distinct expression specificities. Therefore, comprehensively annotating promoters and deciphering their individual regulatory dynamics is critical for gene expression profiling applications, and for our understanding of regulatory complexity. We introduce RAMPAGE, a novel promoter activity profiling approach that combines extremely specific 5'-complete cDNA sequencing with an integrated data analysis workflow to address the limitations of current techniques. RAMPAGE features a streamlined protocol for fast and easy generation of highly multiplexed sequencing libraries, offers very high transcription start site specificity, generates accurate and reproducible promoter expression measurements, and yields extensive transcript connectivity information through paired-end cDNA sequencing. We used RAMPAGE in a genome-wide study of promoter activity throughout 36 stages of the life cycle of Drosophila melanogaster, and describe here a comprehensive dataset that represents the first available developmental timecourse of promoter usage. We found that over 40% of developmentally expressed genes have at least 2 promoters, and that alternative promoters generally implement distinct regulatory programs. Transposable elements, long proposed to play a central role in the evolution of their host genomes through their ability to regulate gene expression, contribute at least 1,300 promoters shaping the developmental transcriptome of D. melanogaster. Hundreds of these promoters drive the expression of annotated genes, and transposons often impart their own expression specificity upon the genes they regulate. These observations provide support for the theory that transposons may drive regulatory innovation through the distribution of stereotyped cis-regulatory modules throughout their host genomes

Définition économique des objectifs de sélection en ovins allaitants. Application à la race Blanche du Massif Central

Les éleveurs d'ovins allaitants sélectionnent leurs meilleures agnelles et brebis, ainsi que les reproducteurs mâles améliorateurs, à la fois sur leurs qualités maternelles et sur les aptitudes bouchères de leurs produits. Pour les aider dans leurs choix, l'INRA, l'Institut de l'Elevage et les organisations de sélection raciales oeuvrent pour mettre à disposition des éleveurs des index synthétiques qui combinent les valeurs génétiques prédites sur les caractères élémentaires en les pondérant selon leur l'importance économique. C'est l'estimation de ces coefficients de pondération économique qui fait l'objet de la présente étude. Actuellement, dans les races ovines à viande, les caractères évalués sont la prolificité, la mortalité, l'aptitude à l'allaitement (valeur laitière), la croissance, la conformation, l'état d'engraissement et le rendement de carcasse. Pour calculer la pondération économique d'un caractère, la méthode adoptée consiste à mesurer le gain attendu sur le profit de l'éleveur par l'amélioration d'une unité physique du caractère. Pour ce faire, les recettes et les coûts d'un élevage Blanc du Massif Central ont été modélisés en fonction des performances zootechniques du troupeau conduit en trois agnelages en deux ans. Les paramètres technico-économiques ont été recueillis auprès des Réseaux d'Elevages, de la station FEDATEST, et d'analyses des données du contrôle de performances. Les caractères les plus importants sont ceux composant la productivité numérique du troupeau : fertilité, prolificité et mortalité. L'augmentation moyenne de ces trois caractères pour un troupeau sur une année permet un gain marginal respectif de 0,76 €, 0,48 €, 1,17 € par femelle présente au 1er janvier et contribue aux deux tiers de l'objectif global. Se classent ensuite les caractères bouchers tels que le gras (9,41 € par mm), la conformation (7,31 € par classe de conformation) et le rendement des carcasses (2,43 € par %). La hiérarchie des caractères est peu dépendante des évolutions des prix de la viande et des prix des concentrés

BJT application expansion by insertion of superjunction

International audienceIn this paper, some high voltage Bipolar Junction Transistors are presented and compared in order to suggest a switch for household appliances with fully turn-on, turn-off control. For the first time, a comparative theoretical study, using 2D simulations, shows that concepts like the "superjunction" improve the static behaviour of conventional BJT. These new structures are compared with a SJMOSFET and an IGBT. The new BJT exhibits lower static losses than SJMOSFET and gives up an interest in bipolar structure

Random perfect lattices and the sphere packing problem

Motivated by the search for best lattice sphere packings in Euclidean spaces of large dimensions we study randomly generated perfect lattices in moderately large dimensions (up to d=19 included). Perfect lattices are relevant in the solution of the problem of lattice sphere packing, because the best lattice packing is a perfect lattice and because they can be generated easily by an algorithm. Their number however grows super-exponentially with the dimension so to get an idea of their properties we propose to study a randomized version of the algorithm and to define a random ensemble with an effective temperature in a way reminiscent of a Monte-Carlo simulation. We therefore study the distribution of packing fractions and kissing numbers of these ensembles and show how as the temperature is decreased the best know packers are easily recovered. We find that, even at infinite temperature, the typical perfect lattices are considerably denser than known families (like A_d and D_d) and we propose two hypotheses between which we cannot distinguish in this paper: one in which they improve Minkowsky's bound phi\sim 2^{-(0.84+-0.06) d}, and a competitor, in which their packing fraction decreases super-exponentially, namely phi\sim d^{-a d} but with a very small coefficient a=0.06+-0.04. We also find properties of the random walk which are suggestive of a glassy system already for moderately small dimensions. We also analyze local structure of network of perfect lattices conjecturing that this is a scale-free network in all dimensions with constant scaling exponent 2.6+-0.1.Comment: 19 pages, 22 figure

The BMV experiment : a novel apparatus to study the propagation of light in a transverse magnetic field

In this paper, we describe in detail the BMV (Bir\'efringence Magn\'etique du Vide) experiment, a novel apparatus to study the propagation of light in a transverse magnetic field. It is based on a very high finesse Fabry-Perot cavity and on pulsed magnets specially designed for this purpose. We justify our technical choices and we present the current status and perspectives.Comment: To be published in the European Physical Journal

The Methyltransferases PRMT4/CARM1 and PRMT5 Control Differentially Myogenesis in Zebrafish

In vertebrates, skeletal myogenesis involves the sequential activation of myogenic factors to lead ultimately to the differentiation into slow and fast muscle fibers. How transcriptional co-regulators such as arginine methyltransferases PRMT4/CARM1 and PRMT5 control myogenesis in vivo remains poorly understood. Loss-of-function experiments using morpholinos against PRMT4/CARM1 and PRMT5 combined with in situ hybridization, quantitative polymerase chain reaction, as well as immunohistochemistry indicate a positive, but differential, role of these enzymes during myogenesis in vivo. While PRMT5 regulates myod, myf5 and myogenin expression and thereby slow and fast fiber formation, PRMT4/CARM1 regulates myogenin expression, fast fiber formation and does not affect slow fiber formation. However, our results show that PRMT4/CARM1 is required for proper slow myosin heavy chain localization. Altogether, our results reveal a combinatorial role of PRMT4/CARM1 and PRMT5 for proper myogenesis in zebrafish