New class of 3D topological insulator in double perovskite

We predict a new class of three-dimensional topological insulators (TIs) in which the spin-orbit coupling (SOC) can more effectively generate a large band gap at $\Gamma$ point. The band gap of conventional TI such as Bi$_2$Se$_3$ is mainly limited by two factors, the strength of SOC and, from electronic structure perspective, the band gap when SOC is absent. While the former is an atomic property, we find that the latter can be minimized in a generic rock-salt lattice model in which a stable crossing of bands {\it at} the Fermi level along with band character inversion occurs for a range of parameters in the absence of SOC. Thus, large-gap TI's or TI's comprised of lighter elements can be expected. In fact, we find by performing first-principle calculations that the model applies to a class of double perovskites A$_2$BiXO$_6$ (A = Ca, Sr, Ba; X = Br, I) and the band gap is predicted up to 0.55 eV. Besides, more detailed calculations considering realistic surface structure indicate that the Dirac cones are robust against the presence of dangling bond at the boundary with a specific termination.Comment: submitted; title changed and new references added; see DOI for published versio

Thinking like a director: Film editing paterns for virtual cinematographic storytelling

International audienceThis paper introduces Film Editing Patterns (FEP), a language to formalize film editing practices and stylistic choices found in movies. FEP constructs are constraints, expressed over one or more shots from a movie sequence that characterize changes in cinematographic visual properties such as shot sizes, camera angles, or layout of actors on the screen. We present the vocabulary of the FEP language, introduce its usage in analyzing styles from annotated film data, and describe how it can support users in the creative design of film sequences in 3D. More specifically, (i) we define the FEP language, (ii) we present an application to craft filmic sequences from 3D animated scenes that uses FEPs as a high level mean to select cameras and perform cuts between cameras that follow best practices in cinema and (iii) we evaluate the benefits of FEPs by performing user experiments in which professional filmmakers and amateurs had to create cinematographic sequences. The evaluation suggests that users generally appreciate the idea of FEPs, and that it can effectively help novice and medium experienced users in crafting film sequences with little training

CsACO4, an ACC oxidase gene regulating male differentiation in cucumber

Ethylene has been implicated as a sex-determining hormone in cucumber: Its exogenous application increases femaleness and gynoecious genotypes were reported to produce more ethylene. 1- aminocyclopropane-1-carboxylate (ACC) oxidase (ACO) is the key enzyme in ethylene biosynthesis. In this study, a 1,188 base pair (bp) fragment was amplified from cucumber (Jinyan-4) genome with degenerated primers derived from the ACO amino acid consensus sequence among different plant species. The putative new gene was analyzed by bioinformatic tools. Phylogenic analysis result of the new gene (CsACO4, GenBank accession number AY450356) was in accordance with the evolution relationship of genetics among various plant species. The result of BLAST showed the sequence presented a very high match with the ACO genes from other plants; the homologue was from 80 to 99%. Using the sequence, a RNA interference (RNAi) transformation vector was constructed through the way of BP cloning. Eleven transgenic plants were obtained. The transgene integrated into cucumber genome was proved with PCR and southern blotting. The morphological exploration showed that the inserted RNAi target fragments could inhibit the endogenous CsACO4 gene expression and that it could regulate male differentiation in the lower nodes in cucumber.Keywords: Cucumber, ACC oxidase gene, RNAi, male differentiatio

Analyse multicouche de la structure et de la forme des journaux

Understanding newspaper structure and design remains a challenging task due to the complex composition of pages with many visual and textual elements. Current approaches have focused on simple design types and analysed only broad classes for the components in a page. In this paper, we propose an approach to obtain a comprehensive understanding of a newspaper page through a multi-layered analysis of structure and design. Taking images of newspaper front pages as input, our approach uses a combination of computer vision techniques to segment newspapers with complex layouts into meaningful blocks of varying degrees of granularity, and convolutional neural network (CNN) to classify each block. The final output presents a visualization of the various layers of design elements present in the newspaper. Compared to previous approaches, our method introduces a much larger set of design-related labels (23 labels against less than 10 before) resulting in a very fine description of the pages, with high accuracy (83%). As a whole, this automated analysis would have potential applications such as cross-medium content adaptation, digital archiving, and UX design.La composition des pages d'un journal est complexe, comprenant de nombreux éléments visuels et textuels. Cela rend difficile l'analyse de la structure et de la forme de ces pages. Les approches actuelles se sont focalisées sur des documents simples et ont analysé uniquement les classes de base des composants d'une page. Dans ce rapport, nous proposons une approche permettant d’obtenir une compréhension complète d’une page de journal grâce à une analyse multicouche de la structure et de la forme. Notre système prend les images de pages de journaux en entrée et comprend deux parties. La première utilise des techniques de vision par ordinateur pour segmenter des pages complexes en blocs significatifs de différents degrés de granularité. La deuxième classe chaque bloc identifié avec un réseau de neurones à convolution (CNN). Le résultat final est une visualisation des différentes couches des composants d'une page. En comparaison des approches précédentes, notre méthode introduit un ensemble beaucoup plus large de classes (23 classes de composants d’une page par rapport à moins de 10 auparavant), donnant une description très fine des pages, avec une bonne précision (83 %). Cette méthode a des applications potentielles telles que l'adaptation de contenu multi-média, l'archivage numérique et la conception UX