194 research outputs found

    An algorithm for linear constraint solving: its incorporation in a prolog meta-interpreter for CLP

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    AbstractThe paper presents an incremental and efficient algorithm for testing the satisfiability of systems of linear equalities, inequalities (strict or unrestricted), and disequalities. In addition, it describes the incorporation of that algorithm into a metalevel interpreter capable of processing both tree constraints and the mentioned linear constraints in the domain of rationals. Important characteristics of the described algorithm are (1) detection of fixed variables within the context of Gaussian elimination, including the simplex method. (2) efficient dereferencing by considering subclasses of solved forms, and (3) efficient testing of inconsistencies between equality and disequality subclasses. The metalevel interpreter is written in Prolog. Examples of its usage are provided. Finally, the paper outlines how the approach may be generalized to consider the efficient and incremental testing of constraint satisfiability in various domains

    Utilisation des données Google Street View pour cartographier la distribution géographique des espÚces. Une étude préliminaire de la processionnaire du pin (Thaumetopoea pityocampa)

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    Article publiĂ© suite Ă  l'Ă©vĂ©nement : MEDINSECT 3 ; Hammamet-Tunis (Tunisie) - (2012-05-08 - 2012-05-11).Mapping species distribution is an important and useful task to monitor invasive species spread or native species expansion under climate change. Unfortunately it requires a lot of occurrence data that are not easily available from literature and that are very time-consuming to collect in the field. For that reason, we designed a survey with the aim to explore to which extent large-scale databases such as Google Street View could be used to derive valid occurrence data. We worked with an insect species, the Pine Processionary Moth (PPM) Thaumetopoea pityocampa because the larvae of that moth build silk nests on its host tree that are easily visible. The presence of the species at one location can therefore be inferred from visual records derived from the panoramic views available from Google Street View. We designed a standardized procedure allowing the evaluation of the presence of the PPM on a large sampling grid (covering 46 848 km2) located in France. Field sampling has been conducted in parallel, which allowed a straightforward comparison between field and Google-derived datasets. Data derived from Google Street View were highly similar to field data as we found an accuracy (percentage of field values correctly predicted using Google Street View) of 92.9%. We conclude that Google database might provide useful occurrence data for mapping the distribution of species which presence can be visually evaluated such as the PPM. More data are needed, however, to assess the range of spatial scales at which Google Street View actually provides reliable occurrence data.La cartographie de la distribution gĂ©ographique des espĂšces est importante pour suivre l’évolution des aires de distribution d’espĂšces invasives ou d’espĂšces natives en expansion gĂ©ographique. Malheureusement, les donnĂ©es nĂ©cessaires sont parfois difficilement accessibles Ă  partir de la littĂ©rature et sont coĂ»teuses Ă  collecter sur le terrain. Pour cette raison, nous avons conçu une Ă©tude dans le but d'explorer dans quelle mesure il est possible d’utiliser les bases de donnĂ©es telles que Google Street View (GSV) pour obtenir des donnĂ©es d’occurrence valides. Nous avons choisi de travailler avec une espĂšce d’insecte, la chenille processionnaire du pin (PP) Thaumetopoea pityocampa car les larves de cette espĂšce se dĂ©veloppent dans le feuillage des arbres hĂŽtes et tissent un nid blanc aisĂ©ment visible. La prĂ©sence de l'espĂšce dans un site donnĂ© peut donc ĂȘtre facilement renseignĂ©e en examinant les vues panoramiques disponibles pour de nombreuses localitĂ©s dans la base de donnĂ©es de Google Street View. Nous avons conçu une procĂ©dure standardisĂ©e permettant d'Ă©valuer la prĂ©sence de la PP Ă  partir des donnĂ©es GSV et nous l’avons mise en oeuvre sur une aire d’étude couvrant 46 848 km2dans la rĂ©gion Centre en France. La distribution de l’espĂšce a Ă©galement Ă©tĂ© dĂ©crite Ă  l’aide d’échantillonnages rĂ©alisĂ©s sur le terrain. Les donnĂ©es issues de l’examen des images Google Street View ont Ă©tĂ© comparĂ©es aux donnĂ©es de terrain et se sont rĂ©vĂ©lĂ©es de bons estimateurs de la prĂ©sence de la processionnaire du pin avec une prĂ©cision (proportion de valeurs correctement estimĂ©es) de 92.9% sur notre zone d’étude pour un maillage de 16 km x 16 km. Ces rĂ©sultats suggĂšrent que l’exploitation des bases de donnĂ©es de GSV pourrait permettre de produire des donnĂ©es Ă©cologiques intĂ©ressantes pour les espĂšces dont la prĂ©sence peut ĂȘtre estimĂ©e visuellement Ă  partir de photographies. Des Ă©tudes complĂ©mentaires sont cependant nĂ©cessaires pour mieux cerner la gamme d’échelles spatiales auxquelles GSV fournit des donnĂ©es d’occurrence fiables

    Interaction of Saccharomyces boulardii with Salmonella enterica Serovar Typhimurium Protects Mice and Modifies T84 Cell Response to the Infection

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    BACKGROUND: Salmonella pathogenesis engages host cells in two-way biochemical interactions: phagocytosis of bacteria by recruitment of cellular small GTP-binding proteins induced by the bacteria, and by triggering a pro-inflammatory response through activation of MAPKs and nuclear translocation of NF-kappaB. Worldwide interest in the use of functional foods containing probiotic bacteria for health promotion and disease prevention has increased significantly. Saccharomyces boulardii is a non-pathogenic yeast used as a probiotic in infectious diarrhea. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we reported that S. boulardii (Sb) protected mice from Salmonella enterica serovar Typhimurium (ST)-induced death and prevented bacterial translocation to the liver. At a molecular level, using T84 human colorectal cancer cells, we demonstrate that incubation with Sb before infection totally abolished Salmonella invasion. This correlates with a decrease of activation of Rac1. Sb preserved T84 barrier function and decreased ST-induced IL-8 synthesis. This anti-inflammatory effect was correlated with an inhibitory effect of Sb on ST-induced activation of the MAPKs ERK1/2, p38 and JNK as well as on activation of NF-kappaB. Electron and confocal microscopy experiments showed an adhesion of bacteria to yeast cells, which could represent one of the mechanisms by which Sb exerts its protective effects. CONCLUSIONS: Sb shows modulating effects on permeability, inflammation, and signal transduction pathway in T84 cells infected by ST and an in vivo protective effect against ST infection. The present results also demonstrate that Sb modifies invasive properties of Salmonella

    Sustained proliferation in cancer: mechanisms and novel therapeutic targets

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    Proliferation is an important part of cancer development and progression. This is manifest by altered expression and/or activity of cell cycle related proteins. Constitutive activation of many signal transduction pathways also stimulates cell growth. Early steps in tumor development are associated with a fibrogenic response and the development of a hypoxic environment which favors the survival and proliferation of cancer stem cells. Part of the survival strategy of cancer stem cells may manifested by alterations in cell metabolism. Once tumors appear, growth and metastasis may be supported by overproduction of appropriate hormones (in hormonally dependent cancers), by promoting angiogenesis, by undergoing epithelial to mesenchymal transition, by triggering autophagy, and by taking cues from surrounding stromal cells. A number of natural compounds (e.g., curcumin, resveratrol, indole-3-carbinol, brassinin, sulforaphane, epigallocatechin-3-gallate, genistein, ellagitannins, lycopene and quercetin) have been found to inhibit one or more pathways that contribute to proliferation (e.g., hypoxia inducible factor 1, nuclear factor kappa B, phosphoinositide 3 kinase/Akt, insulin-like growth factor receptor 1, Wnt, cell cycle associated proteins, as well as androgen and estrogen receptor signaling). These data, in combination with bioinformatics analyses, will be very important for identifying signaling pathways and molecular targets that may provide early diagnostic markers and/or critical targets for the development of new drugs or drug combinations that block tumor formation and progression

    The French national prospective cohort of patients co-infected with HIV and HCV (ANRS CO13 HEPAVIH): Early findings, 2006-2010

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    <p>Abstract</p> <p>Background</p> <p>In France, it is estimated that 24% of HIV-infected patients are also infected with HCV. Longitudinal studies addressing clinical and public health questions related to HIV-HCV co-infection (HIV-HCV clinical progression and its determinants including genetic dimension, patients' experience with these two diseases and their treatments) are limited. The ANRS CO 13 HEPAVIH cohort was set up to explore these critical questions.</p> <p>To describe the cohort aims and organization, monitoring and data collection procedures, baseline characteristics, as well as follow-up findings to date.</p> <p>Methods</p> <p>Inclusion criteria in the cohort were: age > 18 years, HIV-1 infection, chronic hepatitis C virus (HCV) infection or sustained response to HCV treatment. A standardized medical questionnaire collecting socio-demographic, clinical, biological, therapeutic, histological, ultrasound and endoscopic data is administered at enrolment, then every six months for cirrhotic patients or yearly for non-cirrhotic patients. Also, a self-administered questionnaire documenting socio-behavioral data and adherence to HIV and/or HCV treatments is administered at enrolment and yearly thereafter.</p> <p>Results</p> <p>A total of 1,175 patients were included from January 2006 to December 2008. Their median age at enrolment was 45 years and 70.2% were male. The median CD4 cell count was 442 (IQR: 304-633) cells/ÎŒl and HIV RNA plasma viral load was undetectable in 68.8%. Most participants (71.6%) were on HAART. Among the 1,048 HIV-HCV chronically co-infected patients, HCV genotype 1 was predominant (56%) and cirrhosis was present in 25%. As of January, 2010, after a median follow-up of 16.7 months (IQR: 11.3-25.3), 13 new cases of decompensated cirrhosis, nine hepatocellular carcinomas and 20 HCV-related deaths were reported, resulting in a cumulative HCV-related severe event rate of 1.9/100 person-years (95% CI: 1.3-2.5). The rate of HCV-related severe events was higher in cirrhotic patients and those with a low CD4 cells count, but did not differ according to sex, age, alcohol consumption, CDC clinical stage or HCV status.</p> <p>Conclusion</p> <p>The ANRS CO 13 HEPAVIH is a nation-wide cohort using a large network of HIV treatment, infectious diseases and internal medicine clinics in France, and thus is highly representative of the French population living with these two viruses and in care.</p

    ATLAS liquid argon calorimeter front end electronics

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    The ATLAS detector has been designed for operation at CERN's Large Hadron Collider. ATLAS includes a complex system of liquid argon calorimeters. This paper describes the architecture and implementation of the system of custom front end electronics developed for the readout of the ATLAS liquid argon calorimeters

    Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

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    Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30M⊙M_{\odot} for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure
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