565 research outputs found

    Occurrence of the orange wheat blossom midge [Diptera :Cecidomyiidae] in Quebec and its incidence on wheat grain microflora

    Get PDF
    À l'été 1995, on a prélevé des échantillons de blé (Triticum aestivum) dans des champs de diverses régions agricoles du Québec. La présence de larves de la cécidomyie orangée du blé (Sitodiplosis mosellana) fut quantifiée et une évaluation qualitative et quantitative de la microflore des grains fut réalisée. Les pertes moyennes de rendement causées par les larves de la cécidomyie du blé furent estimée à 6,3%. Le pourcentage des épis infestés fut significativement corrélé avec la contamination bactérienne et fongique des grains (r = 0,79). La présence spécifique du Fusarium graminearum dans les grains de blé fut aussi significativement corrélée avec le nombre de larves par épi (r= 0,67) ou par épillet (r= 0,67). Il appert que la cécidomyie du blé pourrait jouer un rôle dans la dissémination du F. graminearum.Samples of wheat spikes (Triticum aestivum) were collected in the summer of 1995 from different crop districts in Quebec and the occurrence of orange wheat blossom midge (Sitodiplosis mosellana) and seed microflora were determined. Estimated yield loss caused by wheat midge larvae averaged 6.3%. The percentage of infested spikes was significantly correlated with total seed contamination by fungi and bacteria (r = 0.79). The specific occurrence of Fusarium graminearum in grains was also significantly correlated with number of larvae per spike (r = 0.67) or per spikelet (r = 0.67). Consequently, the wheat midge might play a role in dissemination of F. graminearum

    OBJETIVOS DEL MARKETING DIGITAL: UNA APROXIMACIÓN AL FUTURO

    Get PDF
    Este artículo tuvo como propósito la revisión asertiva de los objetivos de marketing digital enfocados a tener una aproximación al futuro específicamente en el sector gourmet. Caracterizándose por ser de tipo documental; llegando a la revisión de estudios similares basados en datos provenientes de otros materiales impresos. Se buscó dar una orientación de la importancia que debe ser el establecimiento de los propósitos organizacionales para los restaurantes de comida gourmet con una visión orientada al logro de obtener una buena comunicación con sus consumidores, conociendo sus expectativas a través de los medios digitales, tomando como bases las exposiciones teóricas relacionadas con Sanagustín (2010), Arens (2000), Artal (2011), Tizón (2008) entre otros desarrolladores de temas sobre el marketing digital. Por lo cual se evidencia que las organizaciones de vanguardia, dentro de un mercado global competitivo, buscan involucrarse con los enfoques más actuales que hayan llevado al éxito a diversas empresas quizás dentro del mismo sector o no. Ante estos planteamientos pueden preguntarse sobre esos objetivos que deberían establecer de manera asertiva una empresa, dentro de esta ola de cambios donde convergen estrategias, herramientas, técnicas y filosofía. Esto trae lógicamente una reacción en cadena, originando una manera diferente de gerenciar resaltando la existencia de infinitas opciones para conocer pero al mismo tiempo cubrir con las necesidades de sus clientes

    Structure of shells in complex networks

    Full text link
    In a network, we define shell \ell as the set of nodes at distance \ell with respect to a given node and define rr_\ell as the fraction of nodes outside shell \ell. In a transport process, information or disease usually diffuses from a random node and reach nodes shell after shell. Thus, understanding the shell structure is crucial for the study of the transport property of networks. For a randomly connected network with given degree distribution, we derive analytically the degree distribution and average degree of the nodes residing outside shell \ell as a function of rr_\ell. Further, we find that rr_\ell follows an iterative functional form r=ϕ(r1)r_\ell=\phi(r_{\ell-1}), where ϕ\phi is expressed in terms of the generating function of the original degree distribution of the network. Our results can explain the power-law distribution of the number of nodes BB_\ell found in shells with \ell larger than the network diameter dd, which is the average distance between all pairs of nodes. For real world networks the theoretical prediction of rr_\ell deviates from the empirical rr_\ell. We introduce a network correlation function c(r)r+1/ϕ(r)c(r_\ell)\equiv r_{\ell+1}/\phi(r_\ell) to characterize the correlations in the network, where r+1r_{\ell+1} is the empirical value and ϕ(r)\phi(r_\ell) is the theoretical prediction. c(r)=1c(r_\ell)=1 indicates perfect agreement between empirical results and theory. We apply c(r)c(r_\ell) to several model and real world networks. We find that the networks fall into two distinct classes: (i) a class of {\it poorly-connected} networks with c(r)>1c(r_\ell)>1, which have larger average distances compared with randomly connected networks with the same degree distributions; and (ii) a class of {\it well-connected} networks with c(r)<1c(r_\ell)<1

    Pre-torsors and Galois comodules over mixed distributive laws

    Full text link
    We study comodule functors for comonads arising from mixed distributive laws. Their Galois property is reformulated in terms of a (so-called) regular arrow in Street's bicategory of comonads. Between categories possessing equalizers, we introduce the notion of a regular adjunction. An equivalence is proven between the category of pre-torsors over two regular adjunctions (NA,RA)(N_A,R_A) and (NB,RB)(N_B,R_B) on one hand, and the category of regular comonad arrows (RA,ξ)(R_A,\xi) from some equalizer preserving comonad C{\mathbb C} to NBRBN_BR_B on the other. This generalizes a known relationship between pre-torsors over equal commutative rings and Galois objects of coalgebras.Developing a bi-Galois theory of comonads, we show that a pre-torsor over regular adjunctions determines also a second (equalizer preserving) comonad D{\mathbb D} and a co-regular comonad arrow from D{\mathbb D} to NARAN_A R_A, such that the comodule categories of C{\mathbb C} and D{\mathbb D} are equivalent.Comment: 34 pages LaTeX file. v2: a few typos correcte

    Synchronizing Automata on Quasi Eulerian Digraph

    Full text link
    In 1964 \v{C}ern\'{y} conjectured that each nn-state synchronizing automaton posesses a reset word of length at most (n1)2(n-1)^2. From the other side the best known upper bound on the reset length (minimum length of reset words) is cubic in nn. Thus the main problem here is to prove quadratic (in nn) upper bounds. Since 1964, this problem has been solved for few special classes of \sa. One of this result is due to Kari \cite{Ka03} for automata with Eulerian digraphs. In this paper we introduce a new approach to prove quadratic upper bounds and explain it in terms of Markov chains and Perron-Frobenius theories. Using this approach we obtain a quadratic upper bound for a generalization of Eulerian automata.Comment: 8 pages, 1 figur

    Experimental evidence that female rhesus macaques (Macaca mulatta) perceive variation in male facial masculinity

    Get PDF
    Among many primate species, face shape is sexually dimorphic, and male facial masculinity has been proposed to influence female mate choice and male-male competition. However, whether conspecifics pay attention to facial masculinity has only been assessed in humans. Here, working with free-ranging rhesus macaques, Macaca mulatta, we used a two-alternative look-time experiment to test whether females perceive male facial masculinity. We presented 107 females with pairs of images of male faces – one more masculine and one more feminine – and recorded their looking behaviour. Females looked toward the masculine face longer than the feminine face in more trials than predicted by chance. Although there was no overall difference in average look-time between masculine and feminine faces across all trials, females looked significantly longer at masculine faces in a subset of trials for which the within-pair difference in masculinity was most pronounced. Additionally, the proportion of time subjects looked toward the masculine face increased as the within-pair difference in masculinity increased. This study provides evidence that female macaques perceive variation in male facial shape, a necessary condition for intersexual selection to operate on such a trait. It also highlights the potential impact of perceptual thresholds on look-time experiments

    Chromatin Profiles of Chromosomally Integrated Human Herpesvirus-6A

    Get PDF
    Human herpesvirus-6A (HHV-6A) and 6B (HHV-6B) are two closely related betaherpesviruses that are associated with various diseases including seizures and encephalitis. The HHV-6A/B genomes have been shown to be present in an integrated state in the telomeres of latently infected cells. In addition, integration of HHV-6A/B in germ cells has resulted in individuals harboring this inherited chromosomally integrated HHV-6A/B (iciHHV-6) in every cell of their body. Until now, the viral transcriptome and the epigenetic modifications that contribute to the silencing of the integrated virus genome remain elusive. In the current study, we used a patient-derived iciHHV-6A cell line to assess the global viral gene expression profile by RNA-seq, and the chromatin profiles by MNase-seq and ChIP-seq analyses. In addition, we investigated an in vitro generated cell line (293-HHV-6A) that expresses GFP upon the addition of agents commonly used to induce herpesvirus reactivation such as TPA. No viral gene expression including miRNAs was detected from the HHV-6A genomes, indicating that the integrated virus is transcriptionally silent. Intriguingly, upon stimulation of the 293-HHV-6A cell line with TPA, only foreign promoters in the virus genome were activated, while all HHV-6A promoters remained completely silenced. The transcriptional silencing of latent HHV-6A was further supported by MNase-seq results, which demonstrate that the latent viral genome resides in a highly condensed nucleosome-associated state. We further explored the enrichment profiles of histone modifications via ChIP-seq analysis. Our results indicated that the HHV-6 genome is modestly enriched with the repressive histone marks H3K9me3/H3K27me3 and does not possess the active histone modifications H3K27ac/H3K4me3. Overall, these results indicate that HHV-6 genomes reside in a condensed chromatin state, providing insight into the epigenetic mechanisms associated with the silencing of the integrated HHV-6A genome

    Fractal Analysis of Protein Potential Energy Landscapes

    Full text link
    The fractal properties of the total potential energy V as a function of time t are studied for a number of systems, including realistic models of proteins (PPT, BPTI and myoglobin). The fractal dimension of V(t), characterized by the exponent \gamma, is almost independent of temperature and increases with time, more slowly the larger the protein. Perhaps the most striking observation of this study is the apparent universality of the fractal dimension, which depends only weakly on the type of molecular system. We explain this behavior by assuming that fractality is caused by a self-generated dynamical noise, a consequence of intermode coupling due to anharmonicity. Global topological features of the potential energy landscape are found to have little effect on the observed fractal behavior.Comment: 17 pages, single spaced, including 12 figure

    Effect of Mating Activity and Dominance Rank on Male Masturbation Among Free-Ranging Male Rhesus Macaques

    Get PDF
    Abstract The adaptive function of male masturbation is still poorly understood, despite its high prevalence in humans and other animals. In non-human primates, male masturbation is most frequent among anthropoid monkeys and apes living in multimale-multifemale groups with a promiscuous mating system. In these species, male masturbation may be a non-functional by-product of high sexual arousal or be adaptive by providing advantages in terms of sperm competition or by decreasing the risk of sexually transmitted infections. We investigated the possible functional significance of male masturbation using behavioral data collected on 21 free-ranging male rhesus macaques (Macaca mulatta) at the peak of the mating season. We found some evidence that masturbation is linked to low mating opportunities: regardless of rank, males were most likely to be observed masturbating on days in which they were not observed mating, and lower-ranking males mated less and tended to masturbate more frequently than higher-ranking males. These results echo the findings obtained for two other species of macaques, but contrast those obtained in red colobus monkeys (Procolobus badius) and Cape ground squirrels (Xerus inauris). Interestingly, however, male masturbation events ended with ejaculation in only 15% of the observed masturbation time, suggesting that new hypotheses are needed to explain masturbation in this species. More studies are needed to establish whether male masturbation is adaptive and whether it serves similar or different functions in different sexually promiscuous species
    corecore