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Search Results: 1 - 10 of 209358 matches for " Allison L. Poussard "
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Chemotactic and Inflammatory Responses in the Liver and Brain Are Associated with Pathogenesis of Rift Valley Fever Virus Infection in the Mouse
Kimberly K. Gray equal contributor,Melissa N. Worthy equal contributor,Terry L. Juelich,Stacy L. Agar,Allison Poussard,Dan Ragland,Alexander N. Freiberg,Michael R. Holbrook
PLOS Neglected Tropical Diseases , 2012, DOI: 10.1371/journal.pntd.0001529
Abstract: Rift Valley fever virus (RVFV) is a major human and animal pathogen associated with severe disease including hemorrhagic fever or encephalitis. RVFV is endemic to parts of Africa and the Arabian Peninsula, but there is significant concern regarding its introduction into non-endemic regions and the potentially devastating effect to livestock populations with concurrent infections of humans. To date, there is little detailed data directly comparing the host response to infection with wild-type or vaccine strains of RVFV and correlation with viral pathogenesis. Here we characterized clinical and systemic immune responses to infection with wild-type strain ZH501 or IND vaccine strain MP-12 in the C57BL/6 mouse. Animals infected with live-attenuated MP-12 survived productive viral infection with little evidence of clinical disease and minimal cytokine response in evaluated tissues. In contrast, ZH501 infection was lethal, caused depletion of lymphocytes and platelets and elicited a strong, systemic cytokine response which correlated with high virus titers and significant tissue pathology. Lymphopenia and platelet depletion were indicators of disease onset with indications of lymphocyte recovery correlating with increases in G-CSF production. RVFV is hepatotropic and in these studies significant clinical and histological data supported these findings; however, significant evidence of a pro-inflammatory response in the liver was not apparent. Rather, viral infection resulted in a chemokine response indicating infiltration of immunoreactive cells, such as neutrophils, which was supported by histological data. In brains of ZH501 infected mice, a significant chemokine and pro-inflammatory cytokine response was evident, but with little pathology indicating meningoencephalitis. These data suggest that RVFV pathogenesis in mice is associated with a loss of liver function due to liver necrosis and hepatitis yet the long-term course of disease for those that might survive the initial hepatitis is neurologic in nature which is supported by observations of human disease and the BALB/c mouse model.
Junín Virus Infection Activates the Type I Interferon Pathway in a RIG-I-Dependent Manner
Cheng Huang equal contributor,Olga A. Kolokoltsova equal contributor,Nadezdha E. Yun,Alexey V. Seregin,Allison L. Poussard,Aida G. Walker,Allan R. Brasier,Yingxin Zhao,Bing Tian,Juan Carlos de la Torre,Slobodan Paessler
PLOS Neglected Tropical Diseases , 2012, DOI: 10.1371/journal.pntd.0001659
Abstract: Junín virus (JUNV), an arenavirus, is the causative agent of Argentine hemorrhagic fever, an infectious human disease with 15–30% case fatality. The pathogenesis of AHF is still not well understood. Elevated levels of interferon and cytokines are reported in AHF patients, which might be correlated to the severity of the disease. However the innate immune response to JUNV infection has not been well evaluated. Previous studies have suggested that the virulent strain of JUNV does not induce IFN in human macrophages and monocytes, whereas the attenuated strain of JUNV was found to induce IFN response in murine macrophages via the TLR-2 signaling pathway. In this study, we investigated the interaction between JUNV and IFN pathway in human epithelial cells highly permissive to JUNV infection. We have determined the expression pattern of interferon-stimulated genes (ISGs) and IFN-β at both mRNA and protein levels during JUNV infection. Our results clearly indicate that JUNV infection activates the type I IFN response. STAT1 phosphorylation, a downstream marker of activation of IFN signaling pathway, was readily detected in JUNV infected IFN-competent cells. Our studies also demonstrated for the first time that RIG-I was required for IFN production during JUNV infection. IFN activation was detected during infection by either the virulent or attenuated vaccine strain of JUNV. Curiously, both virus strains were relatively insensitive to human IFN treatment. Our studies collectively indicated that JUNV infection could induce host type I IFN response and provided new insights into the interaction between JUNV and host innate immune system, which might be important in future studies on vaccine development and antiviral treatment.
RIG-I Enhanced Interferon Independent Apoptosis upon Junin Virus Infection
Olga A. Kolokoltsova, Ashley M. Grant, Cheng Huang, Jennifer K. Smith, Allison L. Poussard, Bing Tian, Allan R. Brasier, Clarence J. Peters, Chien-Te Kent Tseng, Juan C. de la Torre, Slobodan Paessler
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0099610
Abstract: Junin virus (JUNV) is the etiological agent of Argentine hemorrhagic fever (AHF), a human disease with a high case-fatality rate. It is widely accepted that arenaviral infections, including JUNV infections, are generally non-cytopathic. In contrast, here we demonstrated apoptosis induction in human lung epithelial carcinoma (A549), human hepatocarcinoma and Vero cells upon infection with the attenuated Candid#1 strain of, JUNV as determined by phosphatidylserine (PS) translocation, Caspase 3 (CASP3) activation, Poly (ADP-ribose) polymerase (PARP) cleavage and/or chromosomal DNA fragmentation. Moreover, as determined by DNA fragmentation, we found that the pathogenic Romero strain of JUNV was less cytopathic than Candid#1 in human hepatocarcinoma and Vero, but more apoptotic in A549 and Vero E6 cells. Additionally, we found that JUNV-induced apoptosis was enhanced by RIG-I signaling. Consistent with the previously reported role of RIG-I like helicase (RLH) signaling in initiating programmed cell death, we showed that cell death or DNA fragmentation of Candid#1-infected A549 cells was decreased upon siRNA or shRNA silencing of components of RIG-I pathway in spite of increased virus production. Similarly, we observed decreased DNA fragmentation in JUNV-infected human hepatocarcinoma cells deficient for RIG-I when compared with that of RIG-I-competent cells. In addition, DNA fragmentation detected upon Candid#1 infection of type I interferon (IFN)-deficient Vero cells suggested a type I IFN-independent mechanism of apoptosis induction in response to JUNV. Our work demonstrated for the first time apoptosis induction in various cells of mammalian origin in response to JUNV infection and partial mechanism of this cell death.
Cross-Layer Energy Analysis and Proposal of a MAC Protocol for Wireless Sensor Networks Dedicated to Building Monitoring Systems  [PDF]
Denis Dessales, No?l Richard, Anne-Marie Poussard, Rodolphe Vauzelle, Christophe Martinsons
Wireless Sensor Network (WSN) , 2013, DOI: 10.4236/wsn.2013.55012
Abstract:

In a sustainable development context, the monitoring systems are essential to study the building energy performances. With the recent technology advances, these systems can be based on wireless sensor networks, where the energy efficiency is the main design challenge. To this end, most of the studies focus on low power Medium Access Control (MAC) protocols to reduce the overall energy consumption of a network. Nevertheless, the performances assessment of these protocols is generally not performed in a realistic way, and does not take into account the performances of the other layers of the OSI model. In this paper, we propose a cross-layer methodology to assess the real performances of a MAC protocol by taking into account the traffic volume, the synchronization losses and more particularly the physical layer performances through a Bit Error Rate (BER) criterion. The simulation results demonstrate clearly the physical layer impact on a sensor lifetime. Finally, the proposal of an energy efficient MAC protocol for a wireless sensor network dedicated to an application of building monitoring is proposed.

Finding Approximate Palindromes in Strings Quickly and Simply
L. Allison
Computer Science , 2004,
Abstract: Described are two algorithms to find long approximate palindromes in a string, for example a DNA sequence. A simple algorithm requires O(n)-space and almost always runs in $O(k.n)$-time where n is the length of the string and k is the number of ``errors'' allowed in the palindrome. Its worst-case time-complexity is $O(n^2)$ but this does not occur with real biological sequences. A more complex algorithm guarantees $O(k.n)$ worst-case time complexity.
Analyse de Pleased to Meet You
Cécile Poussard
ALSIC : Apprentissage des Langues et Systèmes d'Information et de Communication , 1998,
Abstract: Cet article analyse un logiciel. This article reviews a courseware.
Analyse de English Assesssor
Cécile Poussard
ALSIC : Apprentissage des Langues et Systèmes d'Information et de Communication , 1999,
Abstract: Cet article analyse un logiciel. This article reviews a courseware.
Compte-rendu du Congrès RANACLèS 2001
Cécile Poussard
ALSIC : Apprentissage des Langues et Systèmes d'Information et de Communication , 2002,
Abstract: Les 9èmes Journées Nationales de RANACLèS (1999-2001) se sont tenues au CALUP (Centre d'Apprentissage des Langues de l'Université de Provence), faculté St Charles, Marseille, du 29 novembre au 1er décembre 2001. RANACLèS (Rassemblement National des Centres de Langues de l'Enseignement Supérieur), association créée en 1992, est la branche fran aise de CERCLES, Confédération Européenne des Centres de Langues de l'Enseignement Supérieur. Le congrès RANACLèS réunit des responsables de centres ayant pour mission de fournir des formations en langues à des étudiants spécialistes d'autres disciplines (universités, écoles, Instituts Universitaires de Technologie, Instituts Universitaires Professionnalisés...). Les participants, essentiellement des pédagogues de terrain, trouvent, lors du congrès annuel, une occasion de partager leurs expériences, de s'informer et de réfléchir sur leur pratique. Le thème retenu cette année était celui de la motivation. Les ateliers ont présenté des expérimentations "motivantes" intégrant les TICE, essentiellement dans une perspective de pédagogie de projet. L'atelier des exposants a certainement souffert de questions de calendrier (Salon de l'éducation, tout proche, à Paris) et n'a rassemblé que quelques constructeurs (équipement) et quelques diffuseurs. Les conférences ont permis d'approcher la motivation sous différents angles, motivation et politiques linguistiques (Jacques Darras, université de Picardie), motivation et certification (Claude Springer, université Marcel Bloch de Strasbourg), motivation et mondialisation (Louis-Jean Calvet, université de Provence), motivation et histoire de la pensée éducative (Philippe Meirieu, Institut Universitaire de Formation des Ma tres de Lyon), motivation et autonomie dans les dispositifs d'apprentissage autodirigé (Mia Victori, université autonome de Barcelone).
Guider des stratégies de compréhension de l'oral en ALAO : le cas de l'inférence Guiding oral comprehension strategies with CALL: the case of inference
Cécile Poussard
ALSIC : Apprentissage des Langues et Systèmes d'Information et de Communication , 2003, DOI: 10.4000/alsic.2132
Abstract: L'inférence est une des stratégies à l'oeuvre dans le processus de compréhension de l'oral. Quelques exemples de taches d'inférence extraites de la trame pédagogique que nous avons con ue pour un projet de didacticiel d'anglais, montrent comment on peut susciter l'activité interprétative de l'apprenant, en ciblant les taches sur des passages opaques d'interviews et en guidant l'identification des obstacles (traits de l'oralité) et la combinaison d'éléments facilitateurs (éléments discursifs, prosodiques...) pour lui permettre de reconstruire ou compenser ce qui peut poser problème à l'écoute. En proposant un travail conscient et systématique de l'inférence, notre objectif est que cette capacité devienne opératoire chez l'apprenant, qu'elle soit largement automatisée. Inferring is one of the strategies at work in the comprehension process. A few examples of inferring tasks, taken from the pedagogical script that we created for a future CALL (Computer Assisted Language Learning) product, show how the learner interpretation can be elicited, by focusing the tasks on opaque interview extracts and by guiding the identification of obstacles (oral features) and the combination of facilitating elements (discursive, prosodic..., elements) in order to enable the learner to rebuild or compensate for what can be difficult to listen to. By offering conscious and systematic work on inference, our goal is to help the learner build an operating (i.e. mainly automatized) capacity.
Conception et utilisation de séquences d’apprentissage en anglais LANSAD Designing and using learning units in an EFL course
Cécile Poussard
Recherche et Pratiques Pédagogiques en Langues de Spécialité : Cahiers de l'APLIUT , 2012, DOI: 10.4000/apliut.1418
Abstract: Pour répondre aux besoins de formation en langue vivante des étudiants en licence à l’université, des dispositifs mixtes, alliant travail individuel autonome à l’aide des TICE et Travaux Dirigés, ont été mis en place et des séquences d’apprentissage ont été con ues pour l’anglais. La démarche didactique adoptée s’appuie sur une approche par taches et par savoir-faire. Une expérimentation a été conduite et constitue l’objet de cet article. Il s’agissait d’étudier comment les séquences sont per ues et comment elles sont traitées, avec un double objectif :- vérifier l’adéquation des contenus, en termes de difficulté, aux besoins des étudiants ;- s’assurer de l’appropriation par les enseignants de ces séquences.Une enquête a été menée auprès des étudiants, des enseignants et des tuteurs d’accompagnement. L’article expose les modalités de l’enquête, les résultats obtenus, et il rend compte, dans ce cas précis, des différents r les de l’enseignant : facilitateur concepteur et utilisateur. In order to provide modern language courses to all undergraduate students in our university, blended learning courses have been set up, combining autonomous ICT-based sessions and group sessions, and learning units for the English courses have been created. Our didactic approach is skill- and task-based. The article focuses on the experiment that was carried out in order to study how the various learning units are perceived and then how students deal with them, with a double goal :check that the contents meet the students’ needs, in terms of language level or difficulty ;check that teachers make the suggested learning/teaching units theirs.A survey was conducted among students, teachers and tutors. The article presents the circumstances of the survey, the results that were obtained and it accounts for various teacher roles : as facilitator, as designer and as user.
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