335 research outputs found

    Gbrowse Moby: a Web-based browser for BioMoby Services

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    BACKGROUND: The BioMoby project aims to identify and deploy standards and conventions that aid in the discovery, execution, and pipelining of distributed bioinformatics Web Services. As of August, 2006, approximately 680 bioinformatics resources were available through the BioMoby interoperability platform. There are a variety of clients that can interact with BioMoby-style services. Here we describe a Web-based browser-style client – Gbrowse Moby – that allows users to discover and "surf" from one bioinformatics service to the next using a semantically-aided browsing interface. RESULTS: Gbrowse Moby is a low-throughput, exploratory tool specifically aimed at non-informaticians. It provides a straightforward, minimal interface that enables a researcher to query the BioMoby Central web service registry for data retrieval or analytical tools of interest, and then select and execute their chosen tool with a single mouse-click. The data is preserved at each step, thus allowing the researcher to manually "click" the data from one service to the next, with the Gbrowse Moby application managing all data formatting and interface interpretation on their behalf. The path of manual exploration is preserved and can be downloaded for import into automated, high-throughput tools such as Taverna. Gbrowse Moby also includes a robust data rendering system to ensure that all new data-types that appear in the BioMoby registry can be properly displayed in the Web interface. CONCLUSION: Gbrowse Moby is a robust, yet facile entry point for both newcomers to the BioMoby interoperability project who wish to manually explore what is known about their data of interest, as well as experienced users who wish to observe the functionality of their analytical workflows prior to running them in a high-throughput environment

    Langmuir probe measurements in an expanding magnetized plasma

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    Langmuir probe measurements were performed in magnetized expanding plasmas of different compns. Under the assumption that a function fitted to results in argon is valid in other plasmas, it is possible to study the influence of the magnetic field in nitrogen and hydrogen plasmas. The electron d. in nitrogen can be increased by a factor of 10 by the application of a magnetic field of 4.5 mT. In hydrogen the d. can be increased by a factor of 100 by a magnetic field of 20 mT. The dominant ionic species in the magnetized nitrogen and hydrogen plasmas is the at. ion (N+ and H+, resp.). [on SciFinder (R)

    Increase of CXCR3+ T cells impairs Th17 cells recruitment in the small intestine mucosa through IFN-g and IL-18 during treated HIV-1 infection

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    The restoration of CD4+ T cells, especially T-helper type 17 (Th17) cells, remains incomplete in the gut mucosa of most human immunodeficiency virus type 1 (HIV-1)–infected individuals despite sustained antiretroviral therapy (ART). Herein, we report an increase in the absolute number of CXCR3+ T cells in the duodenal mucosa during ART. The frequencies of Th1 and CXCR3+ CD8+ T cells were increased and negatively correlated with CCL20 and CCL25 expression in the mucosa. In ex vivo analyses, we showed that interferon γ, the main cytokine produced by Th1 and effector CD8+ T cells, downregulates the expression of CCL20 and CCL25 by small intestine enterocytes, while it increases the expression of CXCL9/10/11, the ligands of CXCR3. Interleukin 18, a pro-Th1 cytokine produced by enterocytes, also contributes to the downregulation of CCL20 expression and increases interferon γ production by Th1 cells. This could perpetuate an amplification loop for CXCR3-driven Th1 and effector CD8+ T cells recruitment to the gut, while impairing Th17 cells homing through the CCR6-CCL20 axis in treated HIV-1–infected individuals

    Modélisation de l'entretien du paysage par des herbivores en moyenne montagne : une approche multi-agents

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    L'abandon de l'utilisation des ressources herbagères par l'activité pastorale entraîne un appauvrissement de la diversité écologique et spécifique. A terme, cette évolution se traduit par le déplacement des activités humaines hors de ces zones et à un déséquilibre au niveau du territoire national. Un programme de recherche pluridisciplinaire, dans le cadre d'un Groupement d'intérêt Scientifique, a été mis en place dès 1994 pour élaborer de nouveaux modes de gestion qui concilient production agricole et entretien de l'espace en condition de sous chargement (peu d'animaux par unité de surface). Cet article s'inscrit dans une démarche d'acquisition de méthodes afin d'expérimenter des techniques de gestion de pâturage mixte bovins et chevaux selon une hypothèse de complémentarité entre ces deux espèces. La partie informatique présentée vise à simuler les dynamiques animales, végétales et paysagères futures et, à terme, proposer des protocoles de gestion aptes à répondre à ces nouvelles demandes. L'objectif de la modélisation que nous présentons est de simuler le fonctionnement de l'estive, afin de comprendre l'interaction entre l'évolution de la végétation, les déplacements et les actions des animaux en pâture. Un des modes de simulation utilise un système multi-agents. Le modèle conceptuel de la simulation est en cours de validation, il a été formalisé avec la notation graphique du langage de modélisation unifié (UML) et la version actuelle du logiciel est implémentée avec le langage de programmation Java. Pour suivre et enregistrer les localisations des animaux sur le terrain, ceux-ci sont équipés d'un récepteur satellite GPS (Global Positioning System). L'activité de pâturage des animaux est enregistrée par des colliers Ethosys. / The surrender of herbaceous resources by the grazing activity results in an impoverishment of both ecological and specific diversity. On the long term, this trend imposes the localization of human activities far from these zones and a national imbalance. A multidisciplinary research program was set up in 1994 with the aim of elaborating new ways of management, which would contribute to maintain both the productivity and the opened landscapes within the condition of low grazing pressure. This paper exposes the methods we elaborated in order to test several management techniques of grasslands by mean of cattle and horses within the hypothesis of complementarity between these two species. The computer science part of this paper presents the results of simulations of future dynamic behaviors of the animals, vegetation and landscape, in order to propound some management protocols. The simulator is based on a multi-agent system. The conceptual model, formalized with Unified Modeling Language graphical notation is actually in validation phase and the implementation of the software was done in the Java programming language. The following of the animals in the field was done by means of GPS equipments and the animal activity was recorded by Ethosys equipments

    Seahawk: moving beyond HTML in Web-based bioinformatics analysis

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    <p>Abstract</p> <p>Background</p> <p>Traditional HTML interfaces for input to and output from Bioinformatics analysis on the Web are highly variable in style, content and data formats. Combining multiple analyses can therfore be an onerous task for biologists. Semantic Web Services allow automated discovery of conceptual links between remote data analysis servers. A shared data ontology and service discovery/execution framework is particularly attractive in Bioinformatics, where data and services are often both disparate and distributed. Instead of biologists copying, pasting and reformatting data between various Web sites, Semantic Web Service protocols such as MOBY-S hold out the promise of seamlessly integrating multi-step analysis.</p> <p>Results</p> <p>We have developed a program (Seahawk) that allows biologists to intuitively and seamlessly chain together Web Services using a data-centric, rather than the customary service-centric approach. The approach is illustrated with a ferredoxin mutation analysis. Seahawk concentrates on lowering entry barriers for biologists: no prior knowledge of the data ontology, or relevant services is required. In stark contrast to other MOBY-S clients, in Seahawk users simply load Web pages and text files they already work with. Underlying the familiar Web-browser interaction is an XML data engine based on extensible XSLT style sheets, regular expressions, and XPath statements which import existing user data into the MOBY-S format.</p> <p>Conclusion</p> <p>As an easily accessible applet, Seahawk moves beyond standard Web browser interaction, providing mechanisms for the biologist to concentrate on the analytical task rather than on the technical details of data formats and Web forms. As the MOBY-S protocol nears a 1.0 specification, we expect more biologists to adopt these new semantic-oriented ways of doing Web-based analysis, which empower them to do more complicated, <it>ad hoc </it>analysis workflow creation without the assistance of a programmer.</p

    The subcellular localization of the hepatitis C virus non-structural protein NS2 is regulated by an ion channel-independent function of the p7 protein

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    The hepatitis C virus (HCV) p7 ion channel and non-structural protein 2 (NS2) are both required for efficient assembly and release of nascent virions, yet precisely how these proteins are able to influence this process is unclear. Here, we provide both biochemical and cell biological evidence for a functional interaction between p7 and NS2. We demonstrate that in the context of a genotype 1b subgenomic replicon the localization of NS2 is affected by the presence of an upstream p7 with its cognate signal peptide derived from the C terminus of E2 (SPp7). Immunofluorescence analysis revealed that the presence of SPp7 resulted in the targeting of NS2 to sites closely associated with viral replication complexes. In addition, biochemical analysis demonstrated that, in the presence of SPp7, a significant proportion of NS2 was found in a detergent (Triton X-100)-insoluble fraction, which also contained a marker of detergent resistant rafts. In contrast, in replicons lacking p7, NS2 was entirely detergent soluble and the altered localization was lost. Furthermore, we found that serine 168 within NS2 was required for its localization adjacent to replication complexes, but not for its accumulation in the detergent-insoluble fraction. NS2 physically interacted with NS5A and this interaction was dependent on both p7 and serine 168 within NS2. Mutational and pharmacological analyses demonstrated that these effects were not a consequence of p7 ion channel function, suggesting that p7 possesses an alternative function that may influence the coordination of virus genome replication and particle assembly

    A Virtual Testing Approach for Laminated Composites Based on Micromechanics

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    International audienceThe chapter deals with a crucial question for the design of composite structures: how can one predict the evolution of damage up to and including final fracture? Virtual testing, whose goal is to drastically reduce the huge number of industrial tests involved in current characterization procedures, constitutes one of today’s main industrial challenges. In this work, one revisits our multiscale modeling answer through its practical aspects. Some complements regarding identification, kinking, and crack initiation are also given. Finally, the current capabilities and limits of this approach are discussed, as well as the computational challenges that are inherent to “Virtual Structural Testing.

    Multi-Membership and the Effectiveness of Regional Trade Agreements in Western and Southern Africa: A Comparative Study of ECOWAS and SADC

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    Using a gravity model for 35 countries and the years 1995-2006 we estimate the impact of regional trade agreements in Africa (in particular ECOWAS and SADC) and compare this to the a benchmark of North South trade integration (Europe’s preferential trade agreement). We find that • ECOWAS and SADC membership significantly increases bilateral trade flows (and by more than for example preferential trade agreements with the EU do), • SADC membership has a stronger impact compared to ECOWAS and • that the impact of multi-membership critically depends on the characteristics of the overlapping RTA. We find a positive impact if an additional membership complements the integration process of the original RTA: overlapping memberships had a significant positive effect on bilateral trade within the ECOWAS bloc but it is insignificant for SADC
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