3,464 research outputs found

    An optimised method for the production of MERS-CoV spike expressing viral pseudotypes

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    The production and use of pseudotyped viral particles is widely established for many viruses, and applications in the fields of serology and vaccine development are manifold. Viral pseudotypes have proven to be powerful tools to study the effects of viral evolution on serological outcomes, viral tropism and immunogenicity studies. Pseudotyped viruses are chimeric constructs in which the outer (surface) glycoprotein(s) of one virus is combined with the replication-defective viral “core” of another virus. Pseudotypes allow for accurate, sequence-directed, sensitive antibody neutralization assays and antiviral screening to be conducted within a low biosecurity facility and offer a safe and efficient alternative to wildtype virus use. The protocol outlined here represents a rapid and reliable method for the generation of high-titre pseudotype viral particles with the MERS-CoV spike protein on a lentiviral core, and is adapted from previously published protocols. This protocol is optimised for transfection in a 100mm petri dish with 7ml of supernatant harvested, however it can be readily scaled to different production volumes. This protocol has a number of advantages including. 1. Use of readily available reagents 2. Consistent, high virus titres 3. Rapid generation of novel glycoproteins for research into strain variatio

    A Notion of Dynamic Interface for Depth-Bounded Object-Oriented Packages

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    Programmers using software components have to follow protocols that specify when it is legal to call particular methods with particular arguments. For example, one cannot use an iterator over a set once the set has been changed directly or through another iterator. We formalize the notion of dynamic package interfaces (DPI), which generalize state-machine interfaces for single objects, and give an algorithm to statically compute a sound abstraction of a DPI. States of a DPI represent (unbounded) sets of heap configurations and edges represent the effects of method calls on the heap. We introduce a novel heap abstract domain based on depth-bounded systems to deal with potentially unboundedly many objects and the references among them. We have implemented our algorithm and show that it is effective in computing representations of common patterns of package usage, such as relationships between viewer and label, container and iterator, and JDBC statements and cursors

    Aquatic escape for micro-aerial vehicles

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    As our world is experiencing climate changes, we are in need of better monitoring technologies. Most of our planet is covered with water and robots will need to move in aquatic environments. A mobile robotic platform that possesses eïŹƒcient locomotion and is capable of operating in diverse scenarios would give us an advantage in data collection that can validate climate models, emergency relief and experimental biological research. This ïŹeld of application is the driving vector of this robotics research which aims to understand, produce and demonstrate solutions of aerial-aquatic autonomous vehicles. However, small robots face major challenges in operating both in water and in air, as well as transition between those ïŹ‚uids, mainly due to the diïŹ€erence of density of the media. This thesis presents the developments of new aquatic locomotion strategies at small scales that further enlarge the operational domain of conventional platforms. This comprises ïŹ‚ight, shallow water locomotion and the transition in-between. Their operating principles, manufacturing methods and control methods are discussed and evaluated in detail. I present multiple unique aerial-aquatic robots with various water escape mechanisms, spanning over diïŹ€erent scales. The ïŹve robotic platforms showcased share similarities that are compared. The take-oïŹ€ methods are analysed carefully and the underlying physics principles put into light. While all presented research fulïŹls a similar locomotion objective - i.e aerial and aquatic motion - their relevance depends on the environmental conditions and supposed mission. As such, the performance of each vehicle is discussed and characterised in real, relevant conditions. A novel water-reactive fuel thruster is developed for impulsive take-oïŹ€, allowing consecutive and multiple jump-gliding from the water surface in rough conditions. At a smaller scale, the escape of a milligram robotic bee is achieved. In addition, a new robot class is demonstrated, that employs the same wings for ïŹ‚ying as for passive surface sailing. This unique capability allows the ïŹ‚exibility of ïŹ‚ight to be combined with long-duration surface missions, enabling autonomous prolonged aquatic monitoring.Open Acces

    IST Austria Thesis

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    Motivated by the analysis of highly dynamic message-passing systems, i.e. unbounded thread creation, mobility, etc. we present a framework for the analysis of depth-bounded systems. Depth-bounded systems are one of the most expressive known fragment of the π-calculus for which interesting verification problems are still decidable. Even though they are infinite state systems depth-bounded systems are well-structured, thus can be analyzed algorithmically. We give an interpretation of depth-bounded systems as graph-rewriting systems. This gives more flexibility and ease of use to apply depth-bounded systems to other type of systems like shared memory concurrency. First, we develop an adequate domain of limits for depth-bounded systems, a prerequisite for the effective representation of downward-closed sets. Downward-closed sets are needed by forward saturation-based algorithms to represent potentially infinite sets of states. Then, we present an abstract interpretation framework to compute the covering set of well-structured transition systems. Because, in general, the covering set is not computable, our abstraction over-approximates the actual covering set. Our abstraction captures the essence of acceleration based-algorithms while giving up enough precision to ensure convergence. We have implemented the analysis in the PICASSO tool and show that it is accurate in practice. Finally, we build some further analyses like termination using the covering set as starting point

    Multiple neighborhoods in tabu search: successful applications for operations management problems

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    A metaheuristic is a refined solution method able to find a satisfying solution to a difficult problem in a reasonable amount of time. A local search metaheuristic works on a single solution and tries to improve it iteratively. Tabu search is one of the most famous local search, where at each iteration, a neighbor solution is generated from the current solution by performing a specific modification (called a move) on the latter. In contrast with most of the existing literature, the goal of this paper is to present tabu search approaches where different neighborhood structures (i.e., different types of moves) are jointly used. The discussion is illustrated for various operations management problems: truck loading, job scheduling, inventory management, and dimensioning of assembly lines

    Leaf respiration in grapevine (Vitis vinifera 'Chasselas') in relation to environmental and plant factors

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    The leaf respiration (RD) of grapevine (Vitis vinifera 'Chasselas') was measured under field conditions during the growing season in leaves of different physiological ages in relation to the temperature and plant water status. RD increased with the temperature and was particularly high in young growing leaves on primary and lateral shoots. The RD response to the temperature evolved over the season according to the type and age of the leaves and their phenology. Leaf aging (senescence) induced a decrease in RD at the end of the season. At constant temperatures (20 °C), the highest RD rates were measured during the rapid plant growth phase (the Q10 values were also the highest), and they progressively decreased to reach their lowest rates at the end of the growing season. The lowest RD values were measured on leaves that were inserted opposite the clusters of primary shoots at any period during the season. Water stress led to a reduction in RD, especially when the leaf temperature was above 20 °C. The nocturnal RD evolution showed that the RD rates were greatest at nightfall when the nocturnal temperatures were still high and leaf carbohydrate availability was at its highest; the rates gradually decreased to reach the lowest RD values just before dawn

    Financial impact of introducing the Swiss-DRG reimbursement system on potentially avoidable readmissions at a university hospital.

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    QUESTION UNDER STUDY: Thirty-day readmissions can be classified as potentially avoidable (PARs) or not avoidable (NARs) by following a specific algorithm (SQLapeÂź). We wanted to assess the financial impact of the Swiss-DRG system, which regroups some readmissions occurring within 18 days after discharge within the initial hospital stay, on PARs at our hospital. METHODS: First, PARs were identified from all hospitalisations recorded in 2011 at our university hospital. Second, 2012 Swiss-DRG readmission rules were applied, regrouped readmissions (RR) were identified, and their financial impact computed. Third, RRs were classified as potentially avoidable (PARRs), not avoidable (NARRs), and others causes (OCRRs). Characteristics of PARR patients and stays were retrieved, and the financial impact of PARRS was computed. RESULTS: A total of 36,777 hospitalisations were recorded in 2011, of which 3,140 were considered as readmissions (8.5%): 1,470 PARs (46.8%) and 1,733 NARs (53.2%). The 2012 Swiss-DRG rules would have resulted in 910 RRs (2.5% of hospitalisations, 29% of readmissions): 395 PARRs (43% of RR), 181 NARRs (20%), and 334 OCRRs (37%). Loss in reimbursement would have amounted to CHF 3.157 million (0.6% of total reimbursement). As many as 95% of the 395 PARR patients lived at home. In total, 28% of PARRs occurred within 3 days after discharge, and 58% lasted less than 5 days; 79% of the patients were discharged home again. Loss in reimbursement would amount to CHF 1.771 million. CONCLUSION: PARs represent a sizeable number of 30-day readmissions, as do PARRs of 18-day RRs in the 2012 Swiss DRG system. They should be the focus of attention, as the PARRs represent an avoidable loss in reimbursement

    Calculateur d’impact pour la transition Ă©nergĂ©tique

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    Ce travail de Bachelor est rĂ©alisĂ© en Ă©tĂ© 2016 par Guillaume Fallet, Ă©tudiant Ă  la HES- SO Valais/Wallis en filiĂšre informatique de gestion et est suivi par M. Arnaud Zufferey, professeur dans cette mĂȘme Ă©cole. L’idĂ©e est venue du professeur Philippe Jacquod de l’ISI. L’objectif principal est de dĂ©velopper un calculateur en ligne qui permet la visualisation de la transition Ă©nergĂ©tique en Suisse jusqu’à l’annĂ©e 2050. Ce calculateur est composĂ© d’une sĂ©rie de paramĂštres que l’utilisateur peut modifier pour ensuite afficher sous forme de graphiques l’évolution de la consommation ainsi que la production des diffĂ©rentes sources d’électricitĂ©. Le calculateur est entiĂšrement dĂ©veloppĂ© en « HTML / CSS / JavaScript » et est donc accessible depuis un navigateur web

    DataParl 2.0: visualiser le big data du Parlement cantonal

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    Ce rapport a pour idĂ©e principale de fournir des solutions de visualisation de donnĂ©es Ă  l’intention du service parlementaire du canton du Valais. Le mandant a fait part de son souhait de renouveler sa plateforme internet et d’y inclure des visualisations au moyen des donnĂ©es dont elle est propriĂ©taire. L’objectif principal de ce travail est l’implĂ©mentation d’un prototype de portail internet qui mettra en valeur les donnĂ©es du parlement par le biais de visualisation de donnĂ©es. Pour ce faire, la solution a Ă©tĂ© dĂ©veloppĂ©e au moyen des langages HTML, CSS, PHP 5.6 et d’une librairie JavaScript de visualisation de donnĂ©es. L’exĂ©cution de ce projet s’est dĂ©roulĂ©e au travers de la rĂ©alisation d’objectifs dĂ©finis dans le cahier des charges et permettant un avancement par phase. Le travail a dĂ©marrĂ© par l’analyse du contexte de l’entreprise et des donnĂ©es utilisables, puis la dĂ©finition des user stories. Il s’en est suivi la rĂ©alisation d’un Ă©tat de l’art des plateformes semblables avant de dĂ©finir et de choisir les outils techniques permettant la conception du prototype et finalement de dĂ©velopper ce projet. Dans le cadre de la rĂ©alisation pratique de ce travail, une adaptation de la mĂ©thodologie Scrum a Ă©tĂ© appliquĂ©e. Cette Ă©tape achevĂ©e, le prototype a Ă©tĂ© confrontĂ© Ă  l’avis d’un panel qui a permis de faire le point sur la solution choisie et d’évaluer l’intĂ©rĂȘt pour le parlement d’opter pour une telle ouverture. Le prĂ©sent travail s’est concentrĂ© sur les donnĂ©es relatives aux parlementaires, aux groupes politiques ainsi qu’aux scrutins du parlement
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