8,464 research outputs found

    Controle do percevejo-castanho-da-raiz Scaptocoris carvalhoi, Becker 1967 (Hemiptera: cydnidae) com fungos entomopatogĂȘnicos.

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    A pesquisa teve como objetivo avaliar a eficiĂȘncia de isolados dos fungos Metarhizium anisopliae e Beauveria bassiana como agentes de mortalidade do percevejo-castanho Scaptocoris carvalhoi Becker, 1967. Os experimentos foram conduzidos na Embrapa AgropecuĂĄria Oeste, em Dourados, MS. Em condiçÔes de laboratĂłrio, suspensĂ”es de dez isolados de M. anisopliae e 11 de B. bassiana foram aplicadas topicamente no percevejo, inoculando-se 8 5 ”l da suspensĂŁo de 10 conĂ­dios/ml em cada inseto. Utilizou-se o delineamento inteiramente casualizado com cinco repetiçÔes. Cada parcela foi constituĂ­da por 15 insetos (dez adultos e cinco ninfas grandes). Em outro bioensaio foi avaliada a patogenicidade de M. anisopliae (Ma69) para ninfas e adultos, separadamente. Os nĂ­veis de mortalidade do percevejo foram maiores com M. anisopliae, variando de 73,3% a 94,7% contra 10,7% a 78,7% para B. bassiana. Quando ninfas e adultos foram avaliados separadamente nĂŁo houve diferença significativa com relação Ă  mortalidade. Numa outra etapa, foi avaliada a virulĂȘncia de quatro isolados do fungo M. anisopliae (Ma7, Ma69, Ma283 e Ma342) em S. carvalhoi e determinadas a DL e o TL . A DL foi determinada 50 50 50 4 5 6 7 8 preparando concentraçÔes de 10 , 10 , 10 , 10 e 10 conĂ­dios/ml. Os menores valores da DL foram observados com os isolados 50 Ma69 e Ma7 e o maior com Ma283. Os valores de TL variaram de 50 0,32 a 5,84 dias, sem diferirem estatisticamente entre si. Em casa de vegetação foi avaliada a patogenicidade de um isolado de M. anisopliae (Ma69) em ninfas e adultos de S. carvalhoi, aplicando-se o fungo diretamente no solo dos vasos. Utilizou-se o delineamento inteiramente casualizado em 12 repetiçÔes, sendo a parcela constituĂ­da por 15 insetos. Para cada fase do inseto (adulto/ninfa) tratada com fungo houve uma testemunha, totalizando quatro tratamentos. Nos vasos contendo o fungo (Ma69), a percentagem de mortalidade de adultos + ninfas de S. carvalhoi foi de 57,3%, sendo estatisticamente superior Ă  mortalidade verificada nos vasos nĂŁo tratados. Quando ninfas e adultos foram submetidos Ă  presença do fungo, separadamente, o Ă­ndice de mortalidade foi significativamente maior para ninfas (80,8%) do que para adultos (32,2%). Os resultados obtidos evidenciam que o isolado Ma69 Ă© altamente patogĂȘnico para S. carvalhoi, tanto em laboratĂłrio quanto em casa de vegetação, constituindo uma alternativa promissora para sua utilização como inseticida microbiano.bitstream/item/38778/1/BP200524.pd

    Chiral Fermions and Quadratic Divergences

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    In an approach towards naturalness without supersymmetry, renormalization properties of nonsupersymmetric abelian quiver gauge theories are studied. In the construction based on cyclic groups Z_p the gauge group is U(N)^p, the fermions are all in bifundamentals and the construction allows scalars in adjoints and bifundamentals. Only models without adjoint scalars, however, exhibit both chiral fermions and the absence of one-loop quadratic divergences in the scalar propagator.Comment: 11 page

    Using emoji in response to customer reservation requests and service reviews

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    The use of paralinguistic cues—including emoji—in computer-mediated communication has become prevalent in recent years. Brands and service providers have also been using these cues in their communication strategies. And yet, research examining how such emoji use influences customers’ perception and behavior is still scarce. In two experiments (combined ), we tested if using emoji to reply to a customer request (restaurant reservation, Study 1) or online review (hotel experience, Study 2) influenced perceptions of the brands. The emoji used by the brand was always congruent with the valence of the situation. Results from both studies revealed that the presence (vs. absence) of emoji influenced consumers’ perception of the brand/service at several levels. Specifically, the restaurant/hotel was perceived to have a more informal communication style, have a warmer service, and be more modern. In Study 1, we also observed that emoji use had a positive impact on competence perception and reservation intentions. Importantly, these effects of emoji use were not moderated by the valence of the situation. Taken together, our results showed that emoji can influence different perceptions about brands and services and determine how customers relate to brands.info:eu-repo/semantics/publishedVersio

    No evidence for feedback: Unexceptional Low-ionization winds in Host galaxies of Low Luminosity Active Galactic Nuclei at Redshift z ~1

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    We study winds in 12 X-ray AGN host galaxies at z ~ 1. We find, using the low-ionization Fe II 2586 absorption in the stacked spectra, that the probability distribution function (PDF) of the centroid velocity shift in AGN has a median, 16th and 84th percentiles of (-87, -251, +86) km/s respectively. The PDF of the velocity dispersion in AGN has a median, 84th and 16th percentile of (139, 253, 52) km/s respectively. The centroid velocity and the velocity dispersions are obtained from a two component (ISM+wind) absorption line model. The equivalent width PDF of the outflow in AGN has median, 84th and 16th percentiles of (0.4, 0.8, 0.1) Angstrom. There is a strong ISM component in Fe II 2586 absorption with (1.2, 1.5, 0.8) Angstrom, implying presence of substantial amount cold gas in the host galaxies. For comparison, star-forming and X-ray undetected galaxies at a similar redshift, matched roughly in stellar mass and galaxy inclination, have a centroid velocity PDF with percentiles of (-74, -258, +90) km/s, and a velocity dispersion PDF percentiles of (150, 259, 57) km/s. Thus, winds in the AGN are similar to star-formation-driven winds, and are too weak to escape and expel substantial cool gas from galaxies. Our sample doubles the previous sample of AGN studied at z ~ 0.5 and extends the analysis to z ~ 1. A joint reanalysis of the z ~ 0.5 AGN sample and our sample yields consistent results to the measurements above.Comment: 24 pages, 11 figures, accepted in Ap

    Finite dimensional quantizations of the (q,p) plane : new space and momentum inequalities

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    We present a N-dimensional quantization a la Berezin-Klauder or frame quantization of the complex plane based on overcomplete families of states (coherent states) generated by the N first harmonic oscillator eigenstates. The spectra of position and momentum operators are finite and eigenvalues are equal, up to a factor, to the zeros of Hermite polynomials. From numerical and theoretical studies of the large NN behavior of the product λ_m(N)λ_M(N)\lambda\_m(N) \lambda\_M(N) of non null smallest positive and largest eigenvalues, we infer the inequality ÎŽ_N(Q)Δ_N(Q)=σ_N→N→∞<2π\delta\_N(Q) \Delta\_N(Q) = \sigma\_N \overset{<}{\underset{N \to \infty}{\to}} 2 \pi (resp. ÎŽ_N(P)Δ_N(P)=σ_N→N→∞<2π\delta\_N(P) \Delta\_N(P) = \sigma\_N \overset{<}{\underset{N \to \infty}{\to}} 2 \pi ) involving, in suitable units, the minimal (ÎŽ_N(Q)\delta\_N(Q)) and maximal (Δ_N(Q)\Delta\_N(Q)) sizes of regions of space (resp. momentum) which are accessible to exploration within this finite-dimensional quantum framework. Interesting issues on the measurement process and connections with the finite Chern-Simons matrix model for the Quantum Hall effect are discussed

    The effect of thresholding on temporal avalanche statistics

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    We discuss intermittent time series consisting of discrete bursts or avalanches separated by waiting or silent times. The short time correlations can be understood to follow from the properties of individual avalanches, while longer time correlations often present in such signals reflect correlations between triggerings of different avalanches. As one possible source of the latter kind of correlations in experimental time series, we consider the effect of a finite detection threshold, due to e.g. experimental noise that needs to be removed. To this end, we study a simple toy model of an avalanche, a random walk returning to the origin or a Brownian bridge, in the presence and absence of superimposed delta-correlated noise. We discuss the properties after thresholding of artificial timeseries obtained by mixing toy avalanches and waiting times from a Poisson process. Most of the resulting scalings for individual avalanches and the composite timeseries can be understood via random walk theory, except for the waiting time distributions when strong additional noise is added. Then, to compare with a more complicated case we study the Manna sandpile model of self-organized criticality, where some further complications appear.Comment: 15 pages, 12 figures, submitted to J. Stat. Mech., special issue of the UPoN2008 conferenc

    Mixture of Kernels and Iterated Semidirect Product of Diffeomorphisms Groups

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    In the framework of large deformation diffeomorphic metric mapping (LDDMM), we develop a multi-scale theory for the diffeomorphism group based on previous works. The purpose of the paper is (1) to develop in details a variational approach for multi-scale analysis of diffeomorphisms, (2) to generalise to several scales the semidirect product representation and (3) to illustrate the resulting diffeomorphic decomposition on synthetic and real images. We also show that the approaches presented in other papers and the mixture of kernels are equivalent.Comment: 21 pages, revised version without section on evaluatio
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