40 research outputs found

    Using a three-isotope Bayesian mixing model to assess the contribution of refuse dumps in the diet of the yellow-legged gull Larus michahellis

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    SUMMARY.Âż The yellow-legged gull Larus michahellis is usually considered as an opportunistic species that depends on food derived from anthropogenic activity, such as garbage and fishery discards. However, although it has become a problematic species in many Mediterranean countries, there is stillno information about its status in Tunisia. The aim of this work was to assess the differential use of marine and terrestrial resources by the yellow-legged gulls breeding in an urban area on Chikly Island. Dietary reconstructions were performed through the analysis of regurgitates and ÎŽ13C, ÎŽ34S and ÎŽ15N of feathers of fledglings. Contrary to most Mediterranean breeding colonies, and to our expectations, the mixing model showed that yellow-legged gulls from Chikly are above all marine foragers. Whereas the Lake of Tunis was the principal source of food in 2005 and 2007, chicks from 2006 were fed mainly with prey from the Gulf of Tunis. Although the Gulf is located further from the breeding colony and has less fishing activity than the Lake, our study demonstrated that it is used as an alternative foraging habitat. The Bayesian mixing model approach proved to be a useful tool for evaluating temporal variations in the feeding ecology of the colony, which is relevant information in the management of a wild species. This study also demonstrated the importance of isotopic variability among years for inferring diet diversity and food availability for the colony, thereby allowing demographic forecasts when trophic resources vary in abundance or the foraging habitat is disturbed

    Humeral Artery Aneurysm Revealing a Rare Association between Tuberculosis and Behçet’s Disease

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    The association of pulmonary tuberculosis and Behçet’s disease revealed by an aneurysm of the humeral artery is exceptional with a complicated management. We report a case in which the two conditions occurred concomitantly with the vascular complication, apart from any use of immunosuppressive therapy, something that has never been reported in the literature. We report an extremely rare case of a spontaneous rupture of an aneurysm of the humeral artery of a 29-year-old woman, with no history. The patient underwent axillo-humeral bypass. Investigations concluded the diagnosis of Behçet’s disease associated with pulmonary and lymph node tuberculosis. Anti-tuberculous chemotherapy followed by corticosteroids, immunosuppressants and colchicine have been administrated. Based on this observation, we insist on the necessity of searching the symptoms of Behçet’s disease in the presence of arterial involvement when having a young patient. Therapeutic management must include medical treatment to control inflammation and limit the risk of recurrence. Endovascular or surgical treatment is necessary if the arterial involvement is threatening. The association with tuberculosis complicates management and requires close monitoring

    Cardiac tamponade and paroxysmal third-degree atrioventricular block revealing a primary cardiac non-Hodgkin large B-cell lymphoma of the right ventricle: a case report

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    <p>Abstract</p> <p>Introduction</p> <p>Primary cardiac lymphoma is rare.</p> <p>Case Presentation</p> <p>We report the case of a 64-year-old non-immunodeficient Caucasian man, with cardiac tamponade and paroxysmal third-degree atrioventricular block. Echocardiography revealed the presence of a large pericardial effusion with signs of tamponade and a right ventricular mass was suspected. Scanner investigations clarified the sites, extension and anatomic details of myocardial and pericardial infiltration. Surgical resection was performed due to the rapid impairment of his cardiac function. Analysis of the pericardial fluid and histology confirmed the diagnosis of non-Hodgkin large B-cell lymphoma. He was treated with chemotherapy.</p> <p>Conclusion</p> <p>The prognosis remains poor for this type of tumor due to delays in diagnosis and the importance of the site of disease.</p

    Étude et Ă©laboration d’un systĂšme de surveillance et de maintenance prĂ©dictive pour les condensateurs et les batteries utilisĂ©s dans les Alimentations Sans Interruptions (ASI)

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    To ensure power quality and permanently, some electronic system supplies exist. These supplies are the Uninterrupted Power Supplies (UPS). An UPS like any other system may have some failures. This can be a cause of redundancy loss. This load loss causes a maintenance downtime which may represent a high cost. We propose in this thesis to work on two of the most sensitive components in the UPS namely electrolytic capacitors and lead acid batteries. In a first phase, we present the existing surveillance systems for these two components, highlighting their main drawbacks. This allows us to propose the specifications which have to be implemented for this system. For electrolytic capacitors, we detail different stages of characterization ; the aging accelerated standard experimental procedure and their associated results. On the other hand, we present the simulation results of monitoring and failure prediction system retained. We discuss the experimental validation, describing the developed system. We detail the electronic boards designed, implemented algorithms and their respective constraints for a real time implementation. Finally, for lead acid batteries, we present the simulation results of the monitoring system adopted to obtain the SOC and SOH. We describe the aging experimental procedure of charging and discharging cycles of the batteries needed to find a simple and accurate electric models. We explain the aging experimental results and in the end we give suggestions for improving our system to get a more accurate SOH.Pour assurer une Ă©nergie Ă©lectrique de qualitĂ© et de façon permanente, il existe des systĂšmes Ă©lectroniques d’alimentation spĂ©cifiques. Il s’agit des Alimentations Sans Interruptions (ASI). Une ASI comme tout autre systĂšme peut tomber en panne ce qui peut entrainer une perte de redondance. Cette perte induit une maintenance corrective donc une forme d’indisponibilitĂ© ce qui reprĂ©sente un coĂ»t. Nous proposons dans cette thĂšse de travailler sur deux composants parmi les plus sensibles dans les ASI Ă  savoir les condensateurs Ă©lectrolytiques et les batteries au plomb. Dans une premiĂšre phase, nous prĂ©sentons, les systĂšmes de surveillance existants pour ces deux composants en soulignant leurs principaux inconvĂ©nients. Ceci nous permet de proposer le cahier des charges Ă  mettre en Ɠuvre. Pour les condensateurs Ă©lectrolytiques, nous dĂ©taillons les diffĂ©rentes Ă©tapes de caractĂ©risation et de vieillissement ainsi que la procĂ©dure expĂ©rimentale de vieillissement standard accĂ©lĂ©rĂ© et les rĂ©sultats associĂ©s. D’autre part, nous prĂ©sentons les rĂ©sultats de simulation du systĂšme de surveillance et de prĂ©diction de pannes retenu. Nous abordons la validation expĂ©rimentale en dĂ©crivant le systĂšme dĂ©veloppĂ©. Nous dĂ©taillons les cartes Ă©lectroniques conçues, les algorithmes mis en Ɠuvre et leurs contraintes d’implĂ©mentation respectifs pour une rĂ©alisation temps rĂ©el. Enfin, pour les batteries au plomb Ă©tanches, nous prĂ©sentons les rĂ©sultats de simulation du systĂšme de surveillance retenu permettant d’obtenir le SOC et le SOH. Nous dĂ©taillons la procĂ©dure expĂ©rimentale de vieillissement en cycles de charge et dĂ©charge de la batterie nĂ©cessaire pour avoir un modĂšle Ă©lectrique simple et prĂ©cis. Nous expliquons les rĂ©sultats expĂ©rimentaux de vieillissement pour finir avec des propositions d’amĂ©lioration de notre systĂšme afin d’obtenir un SOH plus prĂ©cis

    Study and elaboration of a monitoring and predictive maintenance system for capacitors and batteries used in Uninterruptible Power Supplies (UPS)

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    Pour assurer une Ă©nergie Ă©lectrique de qualitĂ© et de façon permanente, il existe des systĂšmes Ă©lectroniques d’alimentation spĂ©cifiques. Il s’agit des Alimentations Sans Interruptions (ASI). Une ASI comme tout autre systĂšme peut tomber en panne ce qui peut entrainer une perte de redondance. Cette perte induit une maintenance corrective donc une forme d’indisponibilitĂ© ce qui reprĂ©sente un coĂ»t. Nous proposons dans cette thĂšse de travailler sur deux composants parmi les plus sensibles dans les ASI Ă  savoir les condensateurs Ă©lectrolytiques et les batteries au plomb. Dans une premiĂšre phase, nous prĂ©sentons, les systĂšmes de surveillance existants pour ces deux composants en soulignant leurs principaux inconvĂ©nients. Ceci nous permet de proposer le cahier des charges Ă  mettre en Ɠuvre. Pour les condensateurs Ă©lectrolytiques, nous dĂ©taillons les diffĂ©rentes Ă©tapes de caractĂ©risation et de vieillissement ainsi que la procĂ©dure expĂ©rimentale de vieillissement standard accĂ©lĂ©rĂ© et les rĂ©sultats associĂ©s. D’autre part, nous prĂ©sentons les rĂ©sultats de simulation du systĂšme de surveillance et de prĂ©diction de pannes retenu. Nous abordons la validation expĂ©rimentale en dĂ©crivant le systĂšme dĂ©veloppĂ©. Nous dĂ©taillons les cartes Ă©lectroniques conçues, les algorithmes mis en Ɠuvre et leurs contraintes d’implĂ©mentation respectifs pour une rĂ©alisation temps rĂ©el. Enfin, pour les batteries au plomb Ă©tanches, nous prĂ©sentons les rĂ©sultats de simulation du systĂšme de surveillance retenu permettant d’obtenir le SOC et le SOH. Nous dĂ©taillons la procĂ©dure expĂ©rimentale de vieillissement en cycles de charge et dĂ©charge de la batterie nĂ©cessaire pour avoir un modĂšle Ă©lectrique simple et prĂ©cis. Nous expliquons les rĂ©sultats expĂ©rimentaux de vieillissement pour finir avec des propositions d’amĂ©lioration de notre systĂšme afin d’obtenir un SOH plus prĂ©cis.To ensure power quality and permanently, some electronic system supplies exist. These supplies are the Uninterrupted Power Supplies (UPS). An UPS like any other system may have some failures. This can be a cause of redundancy loss. This load loss causes a maintenance downtime which may represent a high cost. We propose in this thesis to work on two of the most sensitive components in the UPS namely electrolytic capacitors and lead acid batteries. In a first phase, we present the existing surveillance systems for these two components, highlighting their main drawbacks. This allows us to propose the specifications which have to be implemented for this system. For electrolytic capacitors, we detail different stages of characterization ; the aging accelerated standard experimental procedure and their associated results. On the other hand, we present the simulation results of monitoring and failure prediction system retained. We discuss the experimental validation, describing the developed system. We detail the electronic boards designed, implemented algorithms and their respective constraints for a real time implementation. Finally, for lead acid batteries, we present the simulation results of the monitoring system adopted to obtain the SOC and SOH. We describe the aging experimental procedure of charging and discharging cycles of the batteries needed to find a simple and accurate electric models. We explain the aging experimental results and in the end we give suggestions for improving our system to get a more accurate SOH

    Constraint-Based University Timetabling for the

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    Abstract. The course timetabling problem at the German University in Cairo has been in existence ever since the establishment of the university in 2003. Courses offered at the university, academic staff resources, and room resources make the problem over-constrained. Currently timetables are manually designed. The process is effort and time consuming and the results are often not satisfactory. In this paper, we provide a description of the problem and we show how it can be modeled as a constraint satisfaction problem. Our system, implemented in SICStus Prolog, generates a good timetable within some minutes instead of by hand some weeks.

    Towards a high level programming paradigm to deploy e-science applications with dynamic workflows on large scale distributed systems

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    This papers targeted scientists and programmers who need to easily develop and run e-science applications on large scale distributed systems. We present a rich programming paradigm and environment used to develop and deploy high performance applications (HPC) on large scale distributed and heterogeneous platforms. We particularly target iterative e-science applications where (i) convergence conditions and number of jobs are not known in advance, (ii) jobs are created on the fly and (iii) jobs could be persistent. We propose two programming paradigms so as to provide intuitive statements enabling an easy writing of HPC e-science applications. Non-expert developers (scientific researchers) can use them to guarantee fast development and efficient deployment of their applications

    A high level framework to develop and run e-science applications on cloud infrastructures

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    This paper presents a generic framework used todevelop and deploy high performance applications (HPC) oncloud infrastrcutures. We particularly target iterative e-scienceapplications where (i) convergence conditions and number of jobsare not known in advance, (ii) jobs are created on the fly and(iii) jobs could be persistent. We propose a framework which provides intuitive statementsenabling an easy writing of HPC e-science applications. Non-expert developers (scientific researchers) can use them toguarantee fast development and efficient deployment of their applications

    Skeleton paradigm for developing e-science applications on distributed platforms

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    This paper targets scientists and programmers who need to develop e-science applications for heterogeneous distributed platforms: Grid, Volunteer computing, cluster and Cloud. We present a rich environment used to develop and deploy high performance applications (HPC) on large scale distributed and heterogeneous platforms. We particularly target iterative e-science applications where (i) convergence conditions and the number of jobs are not known in advance, (ii) jobs are created on the fly and (iii) jobs could be persistent. We propose two paradigms so as to provide intuitive statements enabling an easy writing of HPC e-science applications. Non-expert developers (scientific researchers) can use them to guarantee a fast development and an efficient deployment of their applications

    AreCAPTCHA: Outsourcing Arabic Text Digitization to Native Speakers

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    There has been a recent increasing demand to digitize Arabic books and documents, due to the fact that digital books do not lose quality over time, and can be easily sustained. Meanwhile, the number of Arabic-speaking Internet users is increasing. We propose AreCAPTCHA, a system that digitizes Arabic text by outsourcing it to native Arabic speakers, while offering protective measures to online web forms of Arabic websites. As users interact with AreCAPTCHA, we collect possible digitizations of words that were not recognized by OCR programs. We explain how the system works, the challenges we faced, and promising preliminary evaluation results
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