318 research outputs found

    Automatic generation of simplified weakest preconditions for integrity constraint verification

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    Given a constraint cc assumed to hold on a database BB and an update uu to be performed on BB, we address the following question: will cc still hold after uu is performed? When BB is a relational database, we define a confluent terminating rewriting system which, starting from cc and uu, automatically derives a simplified weakest precondition wp(c,u)wp(c,u) such that, whenever BB satisfies wp(c,u)wp(c,u), then the updated database u(B)u(B) will satisfy cc, and moreover wp(c,u)wp(c,u) is simplified in the sense that its computation depends only upon the instances of cc that may be modified by the update. We then extend the definition of a simplified wp(c,u)wp(c,u) to the case of deductive databases; we prove it using fixpoint induction

    Nearly Complete Genome Sequence of a Novel Phlebovirus-Like Virus Detected in a Human Plasma Sample by High-Throughput Sequencing.

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    Here, we report a novel phlebovirus-like virus sequence detected in a plasma sample from a febrile adult patient collected in the United Republic of Tanzania in 2014. A nearly complete RNA sequence was generated by high-throughput sequencing on a HiSeq 2500 instrument and further confirmed after repeating the analysis, starting from the initial sample

    Peanut Allergen Reaction Thresholds during Controlled Food Challenges in 2 Canadian Randomized Studies (Canada-ARM1 and PISCES)

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    In 2 randomized studies addressing peanut allergy (Canada-Food Allergy Risk Management 1 [NCT01812798] and Peanut Immunotherapy Starting in Canada, Evaluation and DiScovery [NCT0 1601522]), we quantified peanut allergen thresholds to food challenge using Bayesian stacked model averaging to inform policy and clinical practice. About 50% of patients tolerated more than 70 mg (~ ¼ peanut)

    Transient self-potential anomalies associated with recent lava flows at Piton de la Fournaise volcano (Réunion Island, Indian Ocean)

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    International audienceSelf-potential signals are sensitive to various phenomena including ground water flow (streaming potential), thermal gradients (thermoelectric potential), and potentially rapid fluid disruption associated with vaporization of water. We describe transient self-potential anomalies observed over recent (< 9 years) lava flows at Piton de la Fournaise volcano (Reunion Island, Indian Ocean). Repeated self-potential measurements are used to determine the decay of the self-potential signals with time since the emplacement of a set of lava flow. We performed a 9 km-long self-potential profile in February 2004 in the Grand Brûlé area. This profile was repeated in July–August 2006. The second repetition of this profile crossed eight lava flows emplaced between 1998 and 2005 during seven eruptions of Piton de la Fournaise volcano. The self-potential data show clear positive anomalies (up to 330 mV) and spatially correlated with the presence of recent lava flows. The amplitude of the self-potential anomalies decreases exponentially with the age of the lava flows with a relaxation time of not, vert, similar 44 months. We explain these anomalies by the shallow convection of meteoric water and the associated streaming potential distribution but we cannot exclude possible contributions from the thermoelectric effect and the rapid fluid disruption mechanism. This field case evidences for the first time transient self-potential signals associated with recent volcanic deposits. It can be also a shallow analogue to understand the variation of self-potential signals in active geothermal areas and transient self-potential signals associated with dike intrusion at larger depths. The empirical equation we proposed can also be used to diagnose the cooling of recent lava flow on shield volcanoes

    A genomic perspective on the potential of Actinobacillus succinogenes for industrial succinate production

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    <p>Abstract</p> <p>Background</p> <p>Succinate is produced petrochemically from maleic anhydride to satisfy a small specialty chemical market. If succinate could be produced fermentatively at a price competitive with that of maleic anhydride, though, it could replace maleic anhydride as the precursor of many bulk chemicals, transforming a multi-billion dollar petrochemical market into one based on renewable resources. <it>Actinobacillus succinogenes </it>naturally converts sugars and CO<sub>2 </sub>into high concentrations of succinic acid as part of a mixed-acid fermentation. Efforts are ongoing to maximize carbon flux to succinate to achieve an industrial process.</p> <p>Results</p> <p>Described here is the 2.3 Mb <it>A. succinogenes </it>genome sequence with emphasis on <it>A. succinogenes</it>'s potential for genetic engineering, its metabolic attributes and capabilities, and its lack of pathogenicity. The genome sequence contains 1,690 DNA uptake signal sequence repeats and a nearly complete set of natural competence proteins, suggesting that <it>A. succinogenes </it>is capable of natural transformation. <it>A. succinogenes </it>lacks a complete tricarboxylic acid cycle as well as a glyoxylate pathway, and it appears to be able to transport and degrade about twenty different carbohydrates. The genomes of <it>A. succinogenes </it>and its closest known relative, <it>Mannheimia succiniciproducens</it>, were compared for the presence of known Pasteurellaceae virulence factors. Both species appear to lack the virulence traits of toxin production, sialic acid and choline incorporation into lipopolysaccharide, and utilization of hemoglobin and transferrin as iron sources. Perspectives are also given on the conservation of <it>A. succinogenes </it>genomic features in other sequenced Pasteurellaceae.</p> <p>Conclusions</p> <p>Both <it>A. succinogenes </it>and <it>M. succiniciproducens </it>genome sequences lack many of the virulence genes used by their pathogenic Pasteurellaceae relatives. The lack of pathogenicity of these two succinogens is an exciting prospect, because comparisons with pathogenic Pasteurellaceae could lead to a better understanding of Pasteurellaceae virulence. The fact that the <it>A. succinogenes </it>genome encodes uptake and degradation pathways for a variety of carbohydrates reflects the variety of carbohydrate substrates available in the rumen, <it>A. succinogenes</it>'s natural habitat. It also suggests that many different carbon sources can be used as feedstock for succinate production by <it>A. succinogenes</it>.</p

    Ad hoc Joint FAO/WHO Expert Consultation on Risk Assessment of Food Allergens Part 2: Review and establish threshold levels in foods of the priority allergens

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    The main purpose of this second meeting was to establish threshold levels in foods of the priority allergens. Based on the defined approach, the Expert Committee discussed and agreed on the safety objective, which could be described as “to minimise, to a point where further refinement does not meaningfully reduce health impact, the probability of any clinically relevant objective allergic response, as defined by dose distribution modelling of minimum eliciting doses (MEDs) and supported by data regarding severity of symptoms in the likely range of envisioned Reference Doses (RfD)”. The Committee further identified several important considerations to guide decision-making. These included a clear definition of criteria to be met by quantitative data on which reference doses (RfD) are based, supporting data on health manifestations (severity) at the proposed RfD, quality, quantity, availability and accessibility of data (for priority allergens), as well as how to deal with priority allergens for which information supporting one or more of those considerations was lacking.El objetivo principal de esta segunda reunión fue establecer niveles umbral en los alimentos de los alérgenos prioritarios. Sobre la base del enfoque definido, el Comité de Expertos discutió y acordó el objetivo de seguridad, que podría describirse como “minimizar, hasta un punto en el que un mayor refinamiento no reduzca significativamente el impacto en la salud, la probabilidad de cualquier respuesta alérgica objetiva clínicamente relevante, como definido por el modelo de distribución de dosis de dosis mínimas provocadoras (MED) y respaldado por datos sobre la gravedad de los síntomas en el rango probable de dosis de referencia previstas (RfD) ”. El Comité identificó además varias consideraciones importantes para orientar la toma de decisiones. Estos incluyeron una definición clara de los criterios que deben cumplir los datos cuantitativos en los que se basan las dosis de referencia (RfD), datos de apoyo sobre manifestaciones de salud (gravedad) en la RfD propuesta, calidad, cantidad, disponibilidad y accesibilidad de los datos (para alérgenos prioritarios). , así como cómo tratar los alérgenos prioritarios para los que faltaba información que respaldara una o más de esas consideraciones.Instituto de Investigación de Tecnología de AlimentosFil: Baumert, Joseph. Universidad de Nebraska-Lincoln. Departamento de Ciencia y Tecnología de Alimentos; Estados UnidosFil: Brooke-Taylor, Simon. Brooke-Taylor & Co. Consultor australiano de regulación alimentaria y análisis de riesgos (Pty Ltd); Australia.Fil: Crevel, René W.R. René Crevel Consulting Limited; Reino Unido.Fil: Houben, Geert F. Imperial College London. Instituto Nacional del Corazón y los Pulmones; Reino Unido.Fil: Jackson, Lauren. Administración de Alimentos y Medicamentos de los Estados Unidos. División de Ciencia y Tecnología del Procesamiento de Alimentos. Ingeniería de Procesos; Estados UnidosFil: Kyriakidis, Symeon. Laboratorio Estatal de Química General (GCSL).Autoridad Independiente de Ingresos Públicos (IAPR); Grecia.Fil: La Vieille, Sébastien. Universidad Laval. Departamento de Ciencias de los Alimentos; Canadá.Fil: Lee, N Alice. Universidad de Nueva Gales del Sur. Escuela de Química e Ingeniería. Ciencia e ingeniería de los alimentos; Australia.Fil: López, María Cristina. Universidad Nacional de San Martín. Ingeniería de Alimentos; Argentina.Fil: Luccioli, Stefano. Administración de Alimentos y Medicamentos de los Estados Unidos. Centro de Seguridad Alimentaria y Nutrición Aplicada; Estados UnidosFil: O’Mahony, Patrick. Autoridad de Seguridad Alimentaria de Irlanda; Irlanda.Fil: O’Mahony, Patrick. Universidad College Dublin; Irlanda.Fil: Polenta, Gustavo Alberto. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación Tecnología de Alimentos; Argentina.Fil: Polenta, Gustavo Alberto. Instituto de Ciencia y Tecnología de los Sistemas Alimentarios Sustentables (ICyTeSAS) UEDD INTA-CONICET; Argentina.Fil: Pöpping, Bert. Food Consulting Strategically (FOCO); Alemania.Fil: Pöpping, Bert. Comités de Normalización ISO - CEN. Grupo de trabajo CEN Alérgenos Alimentarios (CEN TC 275 WG 12).); Alemania.Fil: Remington, Benjamin C. Remington Consulting Group B.V.; Holanda.Fil: Remington, Benjamin C. Universidad de Nebraska–Lincoln. Programa de Recursos e Investigación de Alergias Alimentarias. Estados UnidosFil: Srikulnath, Sirinrat. Universidad de Kasetsart (UKaset). Instituto de Investigación y Desarrollo de Productos Alimentarios. Centro de Servicio de Aseguramiento de la Calidad de los Alimentos. Unidad de Alérgenos Alimentarios; Tailandia.Fil: Taylor, Stephen L. Universidad de Nebraska-Lincoln. Departamento de Ciencia y Tecnología de Alimentos; Estados UnidosFil: Turner, Paul J. Colegio Imperial de Ciencia, Tecnología y Medicina. Alergia e Inmunología Pediátricas; Inglaterra

    Stochastic Games with Lim Sup Payoff

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    Consider a two-person zero-sum stochastic game with countable state space S, finite action sets A and B for players 1 and 2, respectively, and law of motion p. Let u be a bounded real-valued function defined on the state space S and assume that the payoff from 2 to 1 along a play (or infinit

    Damage of woven composite under tensile and shear stress using infrared thermography and micrographic cuts

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    Infrared thermography was used to study damage developing in woven fabrics. Two different experiments were performed, a ±45° tensile test and a rail shear test. These two different types of tests show different damage scenarios, even if the shear stress/strain curves are similar. The ±45° tension test shows matrix hardening and matrix cracking whereas the rail shear test shows only matrix hardening. The infrared thermography was used to perform an energy balance, which enabled the visualization of the portion of dissipated energy caused by matrix cracking. The results showed that when the resin is subjected to pure shear, a larger amount of energy is stored by the material, whereas when the resin is subjected to hydrostatic pressure, the main part of mechanical energy is dissipated as heat
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