3,349 research outputs found

    Quadratic decomposition of bivariate orthogonal polynomials

    Get PDF
    We describe the relation between the systems of bivariate orthogonal polynomial associated to a symmetric weight function and associated to some particular Christoffel modifications of the quadratic decomposition of the original weight. We analyze the construction of a symmetric bivariate orthogonal polynomial sequence from a given one, orthogonal to a weight function defined on the first quadrant of the plane. In this description, a sort of Backlund type matrix transformations for the involved three term matrix coefficients plays an important role. Finally, we take as a case study relations between the classical orthogonal polynomials defined on the ball and those on the simplex.publishe

    Inferential evaluation and revision in L1 and L2 text comprehension: An eye movement study

    Get PDF
    Text comprehension frequently demands the resolution of no longer plausible interpretations to build an accurate situation model, an ability that might be especially challenging during second language comprehension. Twenty-two native English speakers (L1) and twenty-two highly proficient non-native English speakers (L2) were presented with short narratives in English. Each text required the evaluation and revision of an initial prediction. Eye movements in the text and a comprehension sentence indicated less efficient performance in the L2 than in L1 comprehension, in both inferential evaluation and revision. Interestingly, these effects were determined by individual differences in inhibitory control and linguistic proficiency. Higher inhibitory control reduced the time rereading previous parts of the text (better evaluation) as well as revisiting the text before answering the sentence (better revision) in L2 comprehenders, whereas higher proficiency reduced the time in the sentence when the story was coherent, suggesting better general comprehension in both languages.This research was supported by the grant with ref. 754446-AT3i funded by a MSCA-COFUND Athenea3i and the research project with ref. PSI 2017-89324-C2-2-P funded by MCIN, both to Ana Pérez. Funding for open access charge: Universidad de Granada

    Santuario San Alberto Hurtado Talca

    Get PDF
    61 p.La siguiente memoria tiene por objeto retratar el proceso de la obra abarcando todos los aspectos participantes. de esta manera la siguiente descripcion incluye no solo procesosde diseño y construccion, sino que suma a estos el proceso de gestion de financiamiento e intervencion de la comunidad.es asi como puede entenderse en su totalidad una obra que se desarrolla estrechamente ligada al acontecer de un sector y a sus habitantes

    Integrating phylogeographic patterns of microsatellite and mtDNA divergence to infer the evolutionary history of chamois (genus Rupicapra)

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>The chamois, distributed over most of the medium to high altitude mountain ranges of southern Eurasia, provides an excellent model for exploring the effects of historical and evolutionary events on diversification. Populations have been grouped into two species, <it>Rupicapra pyrenaica </it>from southwestern Europe and <it>R. rupicapra </it>from eastern Europe. However, a previous study of cytochrome b revealed that the two proposed species were non-monophyletic. The reconstruction of phylogenetic relationships between animal species often depends on the markers studied. To further elucidate the evolutionary history of chamois, we extended earlier studies by analysing DNA sequences of four mitochondrial regions (ND1, 12S, tRNApro and Control Region) and microsatellites (20 loci) to include all subspecies and cover its entire distribution range.</p> <p>Results</p> <p>We found discordant microsatellite (μsat) and mitochondrial (mt) DNA phylogenies. Mitochondrial phylogenies form three clades, West, Central and East (mtW, mtC and mtE), at variance with taxonomic classification. Our divergence age estimates indicate an initial separation into branches mtW-mtC and mtE 1.7 million years ago (mya), in the late Pliocene-early Pleistocene, quickly followed by the split of clades mtW and mtC. Clade mtW contains haplotypes from the Iberian peninsula and the western Alps, Clade mtC includes haplotypes from the Apennines and the Massif of Chartreuse and Clade mtE comprises populations to the east of the Alps. Divergence among populations within these three major clades is recent (< 0.5 mya). New microsatellite multilocus genotypes added to previously published data revealed differences between every pair of subspecies, forming three well defined groups (μsatW, μsatC and μsatE) also with a strong geographic signature. Grouping does not correspond with the mitochondrial lineages but is closer to morphology and taxonomic classification. Recent drastic reductions in population size can be noted for the subspecies <it>ornata </it>as an extremely low diversity.</p> <p>Conclusions</p> <p>The phylogeographic patterns for mtDNA and microsatellites suggest an evolutionary history with limited range contractions and expansions during the Quaternary period and reflect a major effect of the Alpine barrier on west-east differentiation. The contrasting phylogenies for mtDNA and microsatellites indicate events of hybridization among highly divergent lineages in the central area of distribution. Our study points to the importance of reticulate evolution, with periods of isolation and reduction of population size followed by expansions and hybridizations, in the diversification at the level of close species or subspecies.</p

    Lax-type pairs in the theory of bivariate orthogonal polynomials

    Full text link
    Sequences of bivariate orthogonal polynomials written as vector polynomials of increasing size satisfy a couple of three term relations with matrix coefficients. In this work, introducing a time-dependent parameter, we analyse a Lax-type pair system for the coefficients of the three term relations. We also deduce several characterizations relating the Lax-type pair, the shape of the weight, Stieltjes function, moments, a differential equation for the weight, and the bidimensional Toda-type systems

    Impact of chitosan-based nanocarriers on cytoskeleton dynamics: current status and challenges

    Get PDF
    Chitosan-based nanocarriers (CS-NCs) show a promising role in improving drugs and bioactive compounds delivery for therapy. However, the effects exerted by CS-NCs at the cellular level, including their recognition and uptake, have not been fully investigated yet. Many factors, including size, shape, concentration, and surface chemistry of CS-NCs, play an important role in determining the types of intracellular signals triggered. The mechanism of uptake and the involvement of the cytoskeleton during the CS-NCs endocytosis variates among the different cell types as well as further effects observed inside cells. In the present work, we discuss the effects induced by CS-NCs per se on the cytoskeleton, a key component in cell architecture and physiology. The focus of this report is made on tumoral and normal biological models in which CS-NCs could differentially affect the cell cytoskeleton. The recent years reports regarding the impact of CS-NCs on cytoskeleton dynamics and the current techniques for its evaluation are summarized and discussed. Understanding mechanisms underlying cytoskeletal impact after cell exposure to CS-NCs is critical for the design of safest value-Added formulations in the biomedical field. Furthermore, this revision points out some interesting aspects of cytoskeletal changes and cell death encompassing anti-Tumoral effects.Fil: Di Santo, Mariana Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Alaimo, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Domínguez Rubio, Ana Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; ArgentinaFil: Pérez, Oscar E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Biológica; Argentin

    The Sas3p and Gcn5p histone acetyltransferases are recruited to similar genes

    Get PDF
    A macroarray platform was used to identify binding sites of yeast histone acetyltransferase catalytic subunits and to correlate their positions with acetylation of lysine 14 of histone H3, revealing that Sas3p and Gcn5p are recruited to similar sets of intensely transcribed genes

    First report of Cylindrocladiella parva and C. peruviana associated with black-foot disease of grapevine in Spain

    Full text link
    Agusti Brisach, C.; Alaniz, S.; Gramaje Pérez, D.; Pérez Sierra, AM.; Armengol Fortí, J.; Landeras, E.; Izquierdo, PM. (2012). First report of Cylindrocladiella parva and C. peruviana associated with black-foot disease of grapevine in Spain. Plant Disease. 96(9):1381-1382. doi:10.1094/PDIS-04-12-0410-PDNS1381138296
    corecore