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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Pneumocystis jiroveci and respiratorey bacterial pathogens in cases of pneumonia at hospitals in Port Elizabeth

Du Plessis, Sarah Jane January 2008 (has links)
Pneumocystis jiroveci, Mycoplasma pneumoniae and Mycobacterium tuberculosis are respiratory pathogens associated with pneumonia, with increasing prevalence of Pneumocystis pneumonia (PcP) and tuberculosis (TB) in AIDS patients. Increased resistance of M. tuberculosis has emphasized the need for rapid susceptibility testing, such as flow cytometry. Sputum specimens (102) were assessed by PCR employing primers directed at the following genes: P. jiroveci: mitochondrial large subunit ribosomal RNA (mtLSUrRNA), dihydropteroate synthase (DHPS) and dihydrofolate reductase (DHFR), and for M. pneumoniae: 16S rRNA and P1 adhesin. Positive P. jiroveci samples were genotyped by PCR-SSCP (single-strand conformation polymorphism) targeting the: internal transcribed spacer region (ITS), intron of the nuclear 26S rRNA gene (26S), variable region of the mitochondrial 26S rRNA gene (mt26S) and β-tubulin gene (β-tub). Multi-drug resistant (MDR-TB) cultures grown in the presence and absence of four antibiotics (rifampicin, isoniazid, ethambutol and ofloxacin) were heat killed, stained with SYTO16 and Propidium Iodide and analysed using flow cytometry. Rifampicin resistance gene mutations were screened by PCR and DNA sequencing. Details of patient’s gender, age, HIV and M. tuberculosis status were provided by the hospitals. Women were seen to be at high risk for community-acquired P. jiroveci colonisation. Overall, prevalence of P. jiroveci was 55.1 percent (54/102 patients). P. jiroveci was mainly associated with HIV (25/102 P. jiroveci positive patients for which clinical data was available) and co-colonisation with M. tuberculosis was observed in 11 cases. Sequence analysis of DHPS and DHFR products found no resistance associated mutations. M. pneumoniae was detected in one patient. Four simple SSCP patterns were identified and there were no co-infections with other P. jiroveci strains. Nine M. tuberculosis samples [8 MDR-TB isolates (NHLS) and M. tuberculosis ATCC® 27294TM] were tested. There was a 53 percent (19 out of 36 tests) agreement of flow cytometry with the BACTEC MGIT 960. Mutations (at two specific codons, namely 516 and 531) in the rifampicin resistance-determining region (RRDR) of the rpoB gene were observed in eight M. tuberculosis isolates. Evaluation of methods for genotyping and drug susceptibility testing of PcP and TB are imperative for epidemiology and drug resistance studies, and impact on treatment protocols.
22

Earnings Management and Compensation: Do Compensation Committees Distinguish between Future Prospect Signaling and Opportunistic Accounting Choices?

HOLDER, ANTHONY DEWAYNE 22 August 2008 (has links)
No description available.
23

Program for the Identification of Actionable Atrial Fibrillation – Analysis of Professional Pharmacy Services (PIAAF-PPS): An Analysis of Service Recipients Following Community Pharmacy Screening

Lancaster, Karla 05 1900 (has links)
Background and Objectives: Community pharmacy screening for chronic disease risk factors can promote early detection. Little is known about how pharmacy services are used post-screening. The PIAAF Pharmacy study screened elderly participants for hypertension, diabetes, and atrial fibrillation (AF) in 26 pharmacies in Ontario and Alberta. The primary objective was to determine whether patients screening at risk for AF, hypertension and diabetes had increased odds and rates of pharmacy service receipt than those at lower risk. Methods: Participants’ pharmacy data were extracted. A conceptual framework of potentially influential factors was constructed. Measurable factors were used as variables in regression analyses. Generalized estimating equations (GEE) were created to model 1) receipt of all pharmacy services, 2) receipt of medication review, and 3) receipt of influenza vaccination. Results: 165 of 535 patients received 229 pharmacy services. 64% were medication reviews and 25% were influenza vaccinations. Screening at high risk for diabetes, hypertension, and AF was not associated with increased receipt of pharmacy services, except for influenza vaccine, which was associated with screening as high risk for diabetes (OR = 1.69 [95% CI 1.09, 2.64]). Screening in October (IRR = 2.85 [95% CI 1.67, 4.84]), eligibility for annual-only medication reviews (IRR = 2.15 [95% CI 1.53, 3.01]), number of medications (IRR = 1.92 [95% CI 1.07, 3.46]), new medications (IRR = 2.00 [95% CI 1.37, 2.93]), and living in Alberta (IRR = 1.46 [95% CI 1.07, 2.01]) were associated with increased rates of receiving pharmacy services. Discussion and Conclusions: Screening results were not associated with increased receipt of pharmacy services, with the exception of influenza vaccine and high risk of diabetes. A gap exists between screening and pharmacy service receipt. Pharmacists can use screening interventions and individual screening results as an opportunity to provide pharmacy services to those with chronic disease risk factors. / Thesis / Master of Health Sciences (MSc) / Community pharmacies may be ideal locations for screening of chronic diseases such as diabetes, high blood pressure, and abnormal heart rhythms. It is not well understood how pharmacy services are used in people after screening for these risk factors. This project aims to see if people screening at higher risk levels were more likely to receive pharmacy services than those at lower risk. We used patients’ pharmacy data to see what services they had received after screening, and then created statistical models to determine which patient-, pharmacy-, community-, and screening-related factors were associated with a greater chance of receiving pharmacy services. Being at risk of diabetes, high blood pressure, and irregular heart rhythms were not associated with a greater likelihood of receiving pharmacy services, except in those at high risk for diabetes—these patients were found be associated with a higher chance of receiving flu shots.
24

Optimality and robustness in opportunistic scheduler design for wireless networks

Sadiq, Bilal 26 October 2010 (has links)
We investigate in detail two multiuser opportunistic scheduling problems in centralized wireless systems: the scheduling of "delay-sensitive" flows with packet delay requirements of a few tens to few hundreds of milliseconds over the air interface, and the scheduling of "best-effort" flows with the objective of minimizing mean file transfer delay. Schedulers for delay-sensitive flows are characterized by a fundamental tradeoff between "maximizing total service rate by being opportunistic" and "balancing unequal queues (or delays) across users". In choosing how to realize this tradeoff in schedulers, our key premise is that "robustness" should be a primary design objective alongside performance. Different performance objectives -- mean packet delay, the tail of worst user's queue distribution, or that of the overall queue distribution -- result in remarkably different scheduling policies. Different design objectives and resulting schedulers are also not equally robust, which is important due to the uncertainty and variability in both the wireless environment and the traffic. The proposed class of schedulers offers low packet delays, less sensitivity to the scheduler parameters and channel characteristics, and a more graceful degradation of service in terms of the fraction of users meeting their delay requirements under transient overloads, when compared with other well-known schedulers. Schedulers for best-effort flows are characterized by a fundamental tradeoff between "maximizing the total service rate" and "prioritizing flows with short residual sizes". We characterize two regimes based on the "degree" of opportunistic gain present in the system. In the first regime -- where the opportunistic capacity of the system increases sharply with the number of users -- the use of residual flow-size information in scheduling will 'not' result in a significant reduction in flow-level delays. Whereas, in the second regime -- where the opportunistic capacity increases slowly with the number of users -- using flow-size information alongside channel state information 'may' result in a significant reduction. We then propose a class of schedulers which offers good performance in either regime, in terms of mean file transfer delays as well as probability of blocking for systems that enforce flow admission control. This thesis provides a comprehensive theoretical study of these fundamental tradeoffs for opportunistic schedulers, as well as an exploration of some of the practical ramifications to engineering wireless systems. / text
25

Middleware Systems for Opportunistic Computing in Challenged Wireless Networks / Support des applications distribuées dans les réseaux mobiles ad hoc à continuité partielle

Benchi, Abdulkader 29 June 2015 (has links)
Les réseaux mobiles opportunistes (ou OppNets, pour Opportunistic Networks) constituent une solution séduisante pour compléter les réseaux fixes d’infrastructure, voire compenser leur absence dans des zones sinistrées ou défavorisées. Les recherches menées ces dernières années ont principalement visé à permettre les transmissions dans les OppNets, mais ceci ne peut être qu’un premier pas vers une réelle exploitation de tels environnements contraints. L’informatique opportuniste (Opportunistic Computing) dépasse le cadre des seules transmissions, et introduit un nouveau paradigme d’exécution de tâches collaboratives dans de tels environnements. Dans ce domaine qu’est l’informatique opportuniste, la conception, la mise en œuvre et le déploiement d’applications distribuées sont des objectifs majeurs. Une application pour OppNet doit pouvoir fonctionner et assurer un niveau de service satisfaisant, tout en supportant les diverses contraintes propres aux OppNets, telles qu’une connectivité fluctuante, un partitionnement chronique du réseau, de longs délais de transmissions, de fréquents échecs de transmission, et des équipements hétérogènes offrant des ressources limitées. La complexité et le coût du développement d’applications pour OppNets peuvent être réduits de manière significative en utilisant des modèles de programmation appropriés. De tels modèles peuvent être fournis par des systèmes intergiciels capables de supporter de manière transparente les contraintes évoquées plus haut. Le travail rapporté dans ce mémoire a porté sur l’étude des contraintes inhérentes aux OppNets, et sur la proposition de solutions appropriées. Parmi les modèles de programmation usuels, certains ont été identifiés comme pouvant être utilisés dans le cadre des OppNets. Sur la base de ces divers modèles de programmation, des systèmes intergiciels opportunistes ont été mis en oeuvre. Ces systèmes supportent respectivement le modèle de messagerie distribuée (sur la base de files d’attentes et de "topics"), le modèle du tuple-space, et la résolution de consensus. Des implémentations complètes ont été réalisées, et le code source est distribué sous licence GPL (GNU General Public License). Ces systèmes ont été évalués par le biais d’expérimentations menées en conditions réelles et par simulation. / Opportunistic networks (OppNets) constitute an appealing solution to complement fixed network infrastructures –or make up for the lack thereof– in challenged areas. Researches in the last few years have mostly addressed the problem of supporting networking in OppNets, yet this can only be a first step towards getting real benefit from these networks. Opportunistic computing goes beyond the concept of opportunistic networking, and provides a new paradigm to enable collaborative computing tasks in such environments. In the realm of opportunistic computing, properly designing, implementing and deploying distributed applications are important tasks. An OppNet-dedicated application must be able to operate and maintain an acceptable level of service while addressing the many problems that can occur in these networks, such as disconnections, partitioning, long transmission delays, transmission failures, resource constraints, frequent changes in topology, and heterogeneous devices. Much of the complexity and cost of building OppNet-dedicated applications can be alleviated by the use of high-level programming models. Such models can be supported by middleware systems capable of transparently addressing all the above-mentioned problems. The work reported in this dissertation focused on providing insight into the fundamental problems posed by OppNets, so as to analyze and solve the problems faced by application developers while dealing with these environments. The research focused on identifying well-known high-level programming models that can be satisfactorily implemented for OppNets, and that can prove useful for application developers. In order to demonstrate the feasibility of application development for OppNets, while assessing the benefits brought about by carefully designed middleware systems, a couple of such systems have been designed, implemented, and evaluated as part of this work. These middleware systems respectively support distributed messaging (through message queues and topics), the tuple-space model, and consensus solving in OppNets. They are supplemented with fully-functional implementations, that can be used in real settings, and that are all distributed under the terms of the GNU General Public License (GPL). Real-life experiments and simulations have been realized so as to evaluate the effectiveness and efficiency of these systems in real conditions.
26

Service composition in opportunistic networks / Composition de services dans des réseaux opportunistes

Baklouti, Fadhlallah 01 March 2019 (has links)
Cette thèse s’inscrit dans le domaine de l’informatique ambiante et del’Internet des objets, et considère des réseaux qui peuvent se formerspontanément et qui sont composés d’équipements fixes ou mobiles. Ceséquipements peuvent communiquer à travers une infrastructure, ou de gré-à-gré en mode ad hoc. Des ruptures de connectivité peuvent apparaître dans le réseau d’unemanière fréquente et imprévisible. Ces ruptures de connectivité peuvents’avérer problématiques dès lors que ces équipements souhaitent accéder àdes ressources offertes par d’autres équipements.L’informatique opportuniste étend le principe des communicationsopportunistes en proposant d’exposer les ressources à travers des serviceset d’accéder à ces services par des techniques et des protocoles decommunication opportunistes qui mettent en œuvre le principe du “store,carry and forward”.Dans cette thèse, nous nous intéressons à la composition de services afin depouvoir combiner les services élémentaires offerts par les équipementsprésents dans le réseau et ainsi proposer aux utilisateurs des services deplus haut niveau et plus riches. La composition de services représente unetâche complexe dans l’informatique opportuniste du fait des ruptures deconnexion.Dans cette thèse, nous proposons une solution pour composer les servicesen utilisant deux stratégies, à savoir la chorégraphie et l’orchestration. Cettesolution repose en outre sur une fonction d’utilité qui permet de sélectionnerles fournisseurs de services. Nous proposons également une versionaméliorée exploitant un cache distribué de données et un mécanismeproactif de composition de services exploitant les profils d’intérêt desutilisateurs. / This thesis is related to the domain of Ubiquitous computing and Internet ofThings (IoT), and focuses on networks that can be formed spontaneously bymobile or fixed devices. These devices can be connected using aninfrastructure, or in a peer-to-peer mode using ad hoc communications.Connection disruptions may occur in the network frequently andunpredictably. These connection disruptions can be problematic when a givendevice tries to access remote resources provided by other devices, or when ittries to offer its own resources to these ones.Opportunistic computing extends the paradigm of opportunistic networkingby abstracting local resources as services accessible remotely using theprotocols of opportunistic networking that implement the "store, carry andforward" principle.In this thesis, we focus on service composition in order to combineelementary services and offer new, rich and high level composite services tousers. Service composition can be a very difficult task to perform inopportunistic networks due to connection disruptions. In this thesis, we propose a solution to compose services using twostrategies: orchestration and choreography. This solution also relies on autility function that selects service providers. We also propose an optimizedversion of our solution that exploits a distributed cache of data and aproactive service composition mechanism based on the user interest profile.
27

Distributed opportunistic argumentation guided by autonomous agent interaction

Martin, Paul William January 2011 (has links)
Within a distributed system, autonomous agents may find it necessary to cooperate in order to achieve their objectives. Interaction protocols provide standard frameworks within which to conduct common classes of interaction, but they are only useful when the agents using them have a common interpretation of the constraints imposed by those protocols. In open systems, where there are no system-wide objectives and components are contributed from a variety of sources, this is difficult to ensure. An agent within a sufficiently complex environment will find it necessary to draw inferences from information sources of varying integrity and completeness. Given flawed or incomplete information, it may be necessary for an agent to resort to nonmonotonic reasoning in order to be able to make concrete decisions within limited windows of opportunity. This can be expected to create inconsistencies in the joint beliefs of agents which can only be repaired by dialogue between peers. To verify and repair all possible sources of inconsistency is impractical for any sizable body of inference however—any belief revision must therefore be subject to prioritisation. In this thesis, we introduce a mechanism by which agents can perform opportunistic argumentation during dialogue in order to perform distributed belief revision. An interaction portrayal uses the protocol for a given interaction to identify the logical constraints which must be resolved during the interaction as it unfolds. It then compares and reconciles the expectations of agents prior to the resolution of those constraints by generating and maintaining a system of arguments. The composition and scope of arguments is restricted in order to minimise the information exchange whilst still trying to ensure that all available admissible viewpoints are adequately represented immediately prior to any decision. This serves both to make interaction more robust (by allowing agents to make decisions based on the distributed wisdom of its peer group without being explicitly directed by a protocol) and to reconcile beliefs in a prioritised fashion (by focusing only on those beliefs which directly influence the outcome of an interaction as determined by its protocol).
28

Synthesis and Molecular Modeling Studies of Bicyclic Inhibitors of Dihydrofolate Reductase, Receptor Tyrosine Kinases and Tubulin

Raghavan, Sudhir 08 March 2016 (has links)
The results from this work are reported into two sections listed below: <br><br> Synthesis: <br><br> Following structural classes of compounds have been designed, synthesized and studied as inhibitors of pjDHFR, RTKs and tubulin: <br> 1. 2,4-Diamino-6-(substituted-arylmethyl)pyrido[2,3-d]pyrimidines <br> 2. 4-((3-Bromophenyl)linked)-6-(substituted-benzyl)-7H-pyrrolo[2,3-d]pyrimidin-2-amines<br> 3. 6-Methyl-5-((substitutedphenyl)thio)-7H-pyrrolo[2,3-d]pyrimidin-2-amines <br> A total of 35 new compounds (excluding intermediates) were synthesized, characterized and submitted for biological evaluation. Results from these studies will be presented in due course. Bulk synthesis of the potent lead compound 170 was carried out to facilitate in vivo evaluation. <br><br> Docking Studies <br><br> Docking studies were performed using LeadIT, MOE, Sybyl or Flexx for target compounds listed above and for other compounds reported by Gangjee et al. against the following targets: <br> 1. Dihydrofolate reductase: human, P. carinii, P. jirovecii (pjDHFR) and T. gondii (tgDHFR)<br> 2. Thymidylate synthase: human (hTS) and T. gondii (tgTS)<br> 3. Receptor tyrosine kinases: VEGFR2, EGFR and PDGFR-β<br> 4. Colchicine binding site of tublulin.<br> Novel homology models were generated and validated for pjDHFR, tgDHFR, tgTS, PDGFR-β and the F36C L65P pjDHFR double mutant. The tgTS homology model generated in this study and employed to design novel inhibitors shows remarkable similarity with the recently published X-ray crystal structures. Docking studies were performed to provide a molecular basis for the observed activity of target compounds against DHFR, RTKs or tubulin. Results from these studies support structure-based and ligand-based medicinal chemistry efforts in order to improve potency and/or selectivity of analogs of the docked compounds against these targets.<br> Novel topomer CoMFA models were developed for tgTS and hTS using a set of 85 bicyclic inhibitors and for RTKs using a set of 60 inhibitors reported by Gangjee et al. The resultant models could be used to explain the potency and/or selectivity differences for selected molecules for tgTS over hTS. Topomer CoMFA maps show differences in steric and/or electronic requirements among the three RTKs, and could be used, in conjuction with other medicinal chemistry approaches, to modulate the selectivity and/or potency of inhibitors with multiple RTK inhibitory potential. Drug design efforts that involve virtual library screening using these topomer CoMFA models in conjunction with traditional medicinal chemistry techniques and docking are currently underway. / Mylan School of Pharmacy and the Graduate School of Pharmaceutical Sciences; / Medicinal Chemistry / PhD; / Dissertation;
29

A Node-Link Perspective on the Impact of Local Conditions in Sensor Networks

Wennerström, Hjalmar January 2016 (has links)
Sensor networks are made up of small battery-powered sensing devices with wireless communication capabilities, enabling the network to monitor the environment in which it is deployed. Through their flexible and cable-free design these networks open up for new deployment scenarios that were previously not plausible such as during a natural disaster. Motivated by scenarios where centralized oversight is not possible the focus of this thesis is to equip nodes with further adaptability to changes in the links it has with other nodes. This is achieved through contributions in three areas focusing on observations from a node-link perspective. First, the impact the local environment has on the nodes is explored by deploying a sensor network outdoors next to a meteorological station to correlate the variations in link quality to the changes in the environment. The work identifies temperature as the main factor, where through further investigations in a controlled setting, a linear relationship between the decrease in signal quality and the increase in temperature is described. Secondly, the thesis address how nodes in a sensor network can be motivated to exchange data by modeling it as a game. The game theoretic design is motivated by the absence of any centralized control and focus on the nodes as individual users in the network. The presented design motivates the selfish nodes to participate in the exchange of sensor data, showing that it is the best strategy. Lastly, by exploring and understanding how connections in a mobile sensor network occur, nodes are given more flexibility to determine how to send and sample sensor data. This adaptability to contact occurrences is shown to provide better ways of sending data by selecting higher quality links as well as making sampling more energy preserving by reducing the rate in the vicinity of other nodes. / CNDS / WISENET
30

Content Dissemination in Mobile Social Networks

Kong, Chenguang 14 December 2016 (has links)
Mobile social networking(MSN) has emerged as an effective platform for social network users to pervasively disseminate the contents such as news, tips, book information, music, video and so on. In content dissemination, mobile social network users receive content or information from their friends, acquaintances or neighbors, and selectively forward the content or information to others. The content generators and receivers have different motivation and requirements to disseminate the contents according to the properties of the contents, which makes it a challenging and meaningful problem to effectively disseminate the content to the appropriate users. In this dissertation, the typical content dissemination scenarios in MSNs are investigated. According to the content properties, the corresponding user requirements are analyzed. First, a Bayesian framework is formulated to model the factors that influence users behavior on streaming video dissemination. An effective dissemination path detection algorithm is derived to detect the reliable and efficient video transmission paths. Second, the authorized content is investigated. We analyze the characteristics of the authorized content, and model the dissemination problem as a new graph problem, namely, Maximum Weighted Connected subgraph with node Quota (MWCQ), and propose two effective algorithms to solve it. Third, the authorized content dissemination problem in Opportunistic Social Networks(OSNs) is studied, based on the prediction of social connection pattern. We then analyze the influence of social connections on the content acquirement, and propose a novel approach, User Set Selection(USS) algorithm, to help social users to achieve fast and accurate content acquirement through social connections.

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