1,218 research outputs found

    Primeiro Registro Da Cochonilha Lecanodiaspis Dendrobii Douglas, 1892 (hemiptera: Coccoidea: Lecanodiaspididae) E Do Parasitoide Associado Cephaleta Sp. (hymenoptera: Pteromalidae) No Brasil

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    Lecanodiaspis dendrobii Douglas, 1892 (Hemiptera: Coccoidea: Lecanodiaspididae) and the associated parasitoid Cephaleta sp. (Hymenoptera: Pteromalidae) are reported for the first time in Brazil. Specimens of this scale insect were collected on branches and stems of Acacia mangium Willd., Leucaena leucocephala (Lam.) de Wit (Fabaceae), Morus nigra L. (Moraceae), Citrus reticulata Blanco (Rutaceae), Tectona grandis L. f. (Verbenaceae), Anacardium occidentale (Anacardiaceae), Annona squamosa L. andXylopia aromatica (Lam.) Mart. (Annonaceae), in three municipalities of the Roraima state. All plants here mentioned are recorded for the first time as a host for L. dendrobii. Morphological characters of L. dendrobii and symptoms presented by the host plants infested by this pest are included in this work. © 2016, Instituto Internacional de Ecologia. All rights reserved.76125025

    Impact of the pulling rate on the redox state and magnetic domains of Fe-Si-O glass ceramic processed by LFZ method

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    This work studies the effect of the pulling rate, varying from 100 to 400 mm/h, on the redox state, structure and magnetic properties of iron oxide bearing silica glasses processed by laser floating zone (LFZ) method. XRD analysis revealed that the maximum crystallinity is obtained in the fibre grown at the lowest pulling rate. A detailed Raman analysis demonstrated that the global content of Fe2+ increases with pulling rate, while the growth under a lower pulling rate promotes the α-Fe2O3 crystallization. Atomic/magnetic force microscopy provided further evidence of phase-separated iron oxide crystallites formation with a high Fe2+/Ftotal ratio as the pulling rate increases. The magnetic measurements performed over a wide temperature range showed that the highest magnetization is found in the fibre grown at the highest pulling rate. A strong correlation between structural-topographical features and the magnetic characteristics of the glass fibres is substantiated.publishe

    Detecting Determinacy in Prolog Programs: 22nd International Conference, ICLP 2006, Seattle, WA, USA, August 17-20, 2006. Proceedings

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    In program development it is useful to know that a call to a Prolog program will not inadvertently leave a choice-point on the stack. Determinacy inference has been proposed for solving this problem yet the analysis was found to be wanting in that it could not infer determinacy conditions for programs that contained cuts or applied certain tests to select a clause. This paper shows how to remedy these serious deficiencies. It also addresses the problem of identifying those predicates which can be rewritten in a more deterministic fashion. To this end, a radically new form of determinacy inference is introduced, which is founded on ideas in ccp, that is capable of reasoning about the way bindings imposed by a rightmost goal can make a leftmost goal deterministic

    Vacuum Polarization Effects in the Lorentz and PCT Violating Electrodynamics

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    In this work we report new results concerning the question of dynamical mass generation in the Lorentz and PCT violating quantum electrodynamics. A one loop calculation for the vacuum polarization tensor is presented. The electron propagator, "dressed" by a Lorentz breaking extra term in the fermion Lagrangian density, is approximated by its first order: this scheme is shown to break gauge invariance. Then we rather consider a full calculation to second order in the Lorentz breaking parameter: we recover gauge invariance and use the Schwinger-Dyson equation to discuss the full photon propagator. This allows a discussion on a possible photon mass shift as well as measurable, observable physical consequences, such as the Lamb-shift.Comment: Latex file, 19 pages, no figures, includes PACS number

    FAS and NF-ÎşB signalling modulate dependence of lung cancers on mutant EGFR

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    Human lung adenocarcinomas with activating mutations in EGFR (epidermal growth factor receptor) often respond to treatment with EGFR tyrosine kinase inhibitors (TKIs), but the magnitude of tumour regression is variable and transient. This heterogeneity in treatment response could result from genetic modifiers that regulate the degree to which tumour cells are dependent on mutant EGFR. Through a pooled RNA interference screen, we show that knockdown of FAS and several components of the NF-ÎşB pathway specifically enhanced cell death induced by the EGFR TKI erlotinib in EGFR-mutant lung cancer cells. Activation of NF-ÎşB through overexpression of c-FLIP or IKK (also known as CFLAR and IKBKB, respectively), or silencing of IÎşB (also known as NFKBIA), rescued EGFR-mutant lung cancer cells from EGFR TKI treatment. Genetic or pharmacologic inhibition of NF-ÎşB enhanced erlotinib-induced apoptosis in erlotinib-sensitive and erlotinib-resistant EGFR-mutant lung cancer models. Increased expression of the NF-ÎşB inhibitor IÎşB predicted for improved response and survival in EGFR-mutant lung cancer patients treated with EGFR TKI. These data identify NF-ÎşB as a potential companion drug target, together with EGFR, in EGFR-mutant lung cancers and provide insight into the mechanisms by which tumour cells escape from oncogene dependence

    Coleta de dados a partir de imagens: considerações sobre a privacidade dos usuários em redes sociais

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    Considering the privacy concerns on users’ data in social networks, the role of images on social networks and the images as data sources, this paper aims to identify how data collection from images is treated in Facebook and Instagram. For this, we identify the main methods for data collection from images, the mentions to data collection from images in Facebook and Instagram policies, and the options that are presented to users for setting up the data collection from images. We conclude that the policies analyzed are vague in several points regarding to data collection from images: they do not specify which data are collected and just list items with an illustrative purpose. These findings highlight the need for studies and actions to raise awareness of social networks users about their privacy in data collection.Considerando a privacidade dos dados dos usuários nas redes sociais, o papel das imagens nas redes sociais e as imagens como fontes de dados, objetiva-se identificar como a coleta de dados a partir de imagens é tratada no Facebook e no Instagram. Para isso, são identificados os principais métodos utilizados para a coleta de dados a partir de imagens no Facebook e no Instagram, as menções à coleta de dados a partir das imagens nas políticas dessas redes sociais, e as opções dos usuários para a configuração desta coleta. Conclui-se que as políticas dessas redes sociais se mostram vagas em diversos momentos no que diz respeito à coleta de dados a partir de imagens, sem especificar quais dados são coletados e listando itens apenas com caráter exemplificativo. Essas conclusões ressaltam a necessidade de conscientização dos usuários de redes sociais acerca de sua privacidade durante a coleta de dados

    Independent Eigenstates of Angular Momentum in a Quantum N-body System

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    The global rotational degrees of freedom in the Schr\"{o}dinger equation for an NN-body system are completely separated from the internal ones. After removing the motion of center of mass, we find a complete set of (2â„“+1)(2\ell+1) independent base functions with the angular momentum â„“\ell. These are homogeneous polynomials in the components of the coordinate vectors and the solutions of the Laplace equation, where the Euler angles do not appear explicitly. Any function with given angular momentum and given parity in the system can be expanded with respect to the base functions, where the coefficients are the functions of the internal variables. With the right choice of the base functions and the internal variables, we explicitly establish the equations for those functions. Only (3N-6) internal variables are involved both in the functions and in the equations. The permutation symmetry of the wave functions for identical particles is discussed.Comment: 24 pages, no figure, one Table, RevTex, Will be published in Phys. Rev. A 64, 0421xx (Oct. 2001

    On the statistical significance of the conductance quantization

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    Recent experiments on atomic-scale metallic contacts have shown that the quantization of the conductance appears clearly only after the average of the experimental results. Motivated by these results we have analyzed a simplified model system in which a narrow neck is randomly coupled to wide ideal leads, both in absence and presence of time reversal invariance. Based on Random Matrix Theory we study analytically the probability distribution for the conductance of such system. As the width of the leads increases the distribution for the conductance becomes sharply peaked close to an integer multiple of the quantum of conductance. Our results suggest a possible statistical origin of conductance quantization in atomic-scale metallic contacts.Comment: 4 pages, Tex and 3 figures. To be published in PR
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