151 research outputs found

    Essential oils from Calyptranthes concinna, C. lucida and C. rubella (Myrtaceae)

    Get PDF
    Os óleos essenciais de Calyptranthes concinna, C. lucida e C. rubella, coletadas no sul do Brasil, foram analisados por GC/FID e GC/MS. Sessenta e dois constituintes foram identificados representando cerca de 98% do óleo. Todas as amostras mostraram-se ricas em sesquiterpenos cíclicos (mais de 90%), principalmente aquelas da via de ciclização dos cadinanos, bisabolanos e germacranos. Os principais constituintes caracterizados foram biciclogermacreno (22,1% em C. concinna; 11,7% em C. rubella), cis-calameneno (10,3% em C. concinna), betacariofileno (16,5% em C. rubella; 9,4% em C. lucida), beta-bisaboleno (25,5% em C. lucida), espatulenol (15,4% em C. rubella) e óxido de cariofileno (7,6% em C. concinna).Essential oils from Calyptranthes concinna, C. lucida and C. rubella, collected in Southern Brazil, were analyzed by GC and GC/MS. Sixty-two compounds were identified representing about 98% of the oil contents. All samples were rich in cyclic sesquiterpenes (more than 90 %), mainly those from cadinane, bisabolane and germacrane cyclization pathway. The mainly components characterized were bicyclogermacrene (22.1% in C. concinna;11.7% in C. rubella), cis-calamenene (10.3% in C. concinna), beta-caryophyllene (16.5% in C. rubella; 9.4% in C. lucida), beta-bisabolene (25.5% in C. lucida), spathulenol (15.4% in C. rubella) and caryophyllene oxide (7.6% in C. concinna)

    EEG Error-Related Potentials Detection With A Bayesian Filter

    Get PDF
    International audienceSeveral studies describe evoked EEG potentials elicited when a subject is aware of an erroneous decision either taken by him or by an external interface. This paper try to detect Error-related potentials (ErrP) elicited when a human user want to monitors an external system upon which he has no control whatsoever. To this end we use a Bayesian filter to classify erroneous or correct events. On average over three subjects, the proposed probabilistic classifier achieves single-trial classification of 85% for correct trials and 71% for erroneous trials

    Etude comparative de vocalisations de bébés humains et de bébés robots

    Get PDF
    In order to assess infants' motor skills during speech development, we used a statistical model of the vocal tract that integrates growth of the effector system. This model allowed us to infer, from actual vocalizations, the likeliest explored acoustic regions, articulatory degrees of freedom and vocal tract shapes, and to test MacNeilage and Davis' cooccurrence hypothesis. Our results will feed the building of a virtual robot, modelling speech development

    Crossing Boundaries: Tapestry Within the Context of the 21st Century

    Get PDF
    International audienceGraphical model processing is a central problem in artificial intelligence. The optimization of the combined cost of a network of local cost functions federates a variety of famous problems including CSP, SAT and Max-SAT but also optimization in stochastic variants such as Markov Random Fields and Bayesian networks. Exact solving methods for these problems typically include branch and bound and local inference-based bounds.In this paper we are interested in understanding when and how dynamic programming based optimization can be used to efficiently enforce soft local consistencies on Global Cost Functions, defined as parameterized families of cost functions of unbounded arity. Enforcing local consistencies in cost function networks is performed by applying so-called Equivalence Preserving Transformations (EPTs) to the cost functions. These EPTs may transform global cost functions and make them intractable to optimize.We identify as tractable projection-safe those global cost functions whose optimization is and remains tractable after applying the EPTs used for enforcing arc consistency. We also provide new classes of cost functions that are tractable projection-safe thanks to dynamic programming.We show that dynamic programming can either be directly used inside filtering algorithms, defining polynomially DAG-filterable cost functions, or emulated by arc consistency filtering on a Berge-acyclic network of bounded-arity cost functions, defining Berge-acyclic network-decomposable cost functions. We give examples of such cost functions and we provide a systematic way to define decompositions from existing decomposable global constraints.These two approaches to enforcing consistency in global cost functions are then embedded in a solver for extensive experiments that confirm the feasibility and efficiency of our proposal

    Antiplasmodial volatile extracts from Cleistopholis patens Engler & Diels and Uvariastrum pierreanum Engl. (Engl. & Diels) (Annonaceae) growing in Cameroon

    Get PDF
    In a search for alternative treatment for malaria, plant-derived essential oils extracted from the stem barks and leaves of Cleistopholis patens and Uvariastrum pierreanum (Annonaceae) were evaluated in vitro for antiplasmodial activity against the W2 strain of Plasmodium falciparum. The oils were obtained from 500 g each of stem barks and leaves, respectively, by hydrodistillation, using a Clevenger-type apparatus with the following yields: 0.23% and 0.19% for C. patens and 0.1% and 0.3% for U. pierreanum (w/w relative to dried material weight). Analysis of 10% (v/v) oil in hexane by gas chromatography and mass spectrometry identified only terpenoids in the oils, with over 81% sesquiterpene hydrocarbons in C. patens extracts and U. pierreanum stem bark oil, while the leaf oil from the latter species was found to contain a majority of monoterpenes. For C. patens, the major components were α-copaene, δ-cadinene, and germacrene D for the stem bark oil and β-caryophyllene, germacrene D, and germacrene B for the leaf oil. The stem bark oil of U. pierreanum was found to contain mainly β-bisabolene and α-bisabolol, while α- and β-pinenes were more abundant in the leaf extract. Concentrations of oils obtained by diluting 1-mg/mL stock solutions were tested against P. falciparum in culture. The oils were active, with IC50 values of 9.19 and 15.19 μg/mL for the stem bark and leaf oils, respectively, of C. patens and 6.08 and 13.96 μg/mL, respectively, for those from U. pierreanum. These results indicate that essential oils may offer a promising alternative for the development of new antimalarials

    Structural determinants of specific DNA-recognition by the THAP zinc finger

    Get PDF
    Human THAP1 is the prototype of a large family of cellular factors sharing an original THAP zinc-finger motif responsible for DNA binding. Human THAP1 regulates endothelial cell proliferation and G1/S cell-cycle progression, through modulation of pRb/E2F cell-cycle target genes including rrm1. Recently, mutations in THAP1 have been found to cause DYT6 primary torsion dystonia, a human neurological disease. We report here the first 3D structure of the complex formed by the DNA-binding domain of THAP1 and its specific DNA target (THABS) found within the rrm1 target gene. The THAP zinc finger uses its double-stranded β-sheet to fill the DNA major groove and provides a unique combination of contacts from the β-sheet, the N-terminal tail and surrounding loops toward the five invariant base pairs of the THABS sequence. Our studies reveal unprecedented insights into the specific DNA recognition mechanisms within this large family of proteins controlling cell proliferation, cell cycle and pluripotency

    Les figures de la relativité dans "Le temps retrouvé" et "Finnegans wake"

    No full text
    PARIS3-BU (751052102) / SudocPARIS-SORBONNE-BIU Centrale (751052105) / SudocSudocFranceF
    corecore