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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.
71

Development and evaluation of an oral fixed–dose triple combination dosage form for artesunate, dapsone and proguanil / van der Merwe, A.J.

Van der Merwe, Adriana Johanna January 2011 (has links)
Malaria is a life–threatening disease caused by Plasmodium spp and causes over one million deaths annually. The complex life cycle of the malaria parasite offers several points of attack for the antimalarial drugs. The rapid spread of resistance against antimalarial drugs, especially chloroquine and pyrimethamine–sulphadoxine, emphasises the need for new alternatives or modification of existing drugs. Artemisinin–based combination therapies (ACT’s) with different targets prevent or delay the development of drug resistance and therefore have been adopted as first–line therapy by all endemic countries. Proguanil–dapsone, an antifolate combination is more active than pyrimethamine–sulphadoxine and is being considered as an alternative to pyrimethamine–sulphadoxine. Artesunate–proguanil–dapsone is a new ACT that has wellmatched pharmacokinetics and is relatively rapidly eliminated; therefore there is a reduced risk of exposure to any single compound and potentially a decreasing risk of resistance. A few studies have been done on a triple fixed–dose combination therapy for malaria treatment and such a combination for artesunate, proguanil and dapsone are not currently investigated, manufactured or distributed. The aim of this study was to develop a triple fixed–dose combination for artesunate, proguanil and dapsone. The formulation was developed in three phases; basic formulation development, employing factorial design to obtain two possible optimised formulations and evaluating the optimised formulations. During the formulation development the most suitable manufacturing procedure and excipients were selected. A full 24 factorial design (four factors at two levels) was used to obtain the optimised formulations. As end–points to identify the optimised formulations, weight variation, friability, crushing strength and disintegration of the tablets, were used. Statistical analysis (one way ANOVA) was used to identify optimal formulations. To identify any interaction between the active pharmaceutical ingredients (API’s) and the API’s and excipients, differential scanning calorimetry was done. Flow properties of the powder mixtures (of the optimised formulations) were characterised by means of angle of repose; critical orifice diameter (COD); bulk density and tapped density; and flow rate. Tablets of the two optimised powder formulations were compressed. The tablets were evaluated and characterised in terms of weight variation, friability, crushing strength, disintegration and dissolution behaviour. Initial formulation development indicated that wet granulation was the most suitable manufacturing method. The results from the factorial design indicated that different amounts (% w/w) of the lubricant and binder as well as two different fillers influenced the weight variation, crushing strength and disintegration statistically significant. Two formulations containing two different fillers (microcrystalline cellulose or Avicel® PH 101, and lactose or Granulac® 200) were found to be within specifications and ideal for manufacturing. Tablets prepared from the FA formulation (formulation containing Avicel® PH 101) complied with the standards and guidelines for weight variation, friability, crushing strength and disintegration as set by the British Pharmacopoeia (BP). Tablets had an average crushing strength of 121.56 ± 0.022 N. Tablets disintegrated within 52.00 seconds and a maximum weight loss of 0.68% occurred during the friability test. Weight variation of the tablets prepared from the FG formulation (formulation containing Granulac® 200) complied with the standards. Average crushing strength was 91.99 ± 6.008 N and the tablets disintegrated within 140.00 seconds. Percentage friability (1.024%) did not comply with the guideline of a percentage friability of less than 1%, however, no cracked or broken tablets were seen. Dissolution showed that 98, 93 and 94% of artesunate, proguanil and dapsone were respectively released (of the label value) within 15 minutes for the FA formulations. Release of artesunate, proguanil and dapsone for the FG formulation was 62, 85 and 92% for the same time period. The release of the three API’s (the FG formulation) increased to 78, 89 and 92%, respectively, after 45 minutes. / Thesis (M.Sc. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2012.
72

Designing and implementing a small scale Internet Service Provider

Brown, Johan, Gustafsson Brokås, Alexander, Hurtig, Niklas, Johansson, Tobias January 2009 (has links)
The objective of this thesis is to design and implement a small scaleInternet Service Provider (ISP) for the NetCenter sub department atMälardalen University. The ISP is intended to give NetCenter a networkseparate from the University’s network, providing them with a moreflexible environment for lab purposes. This will give their students anopportunity to experience a larger backbone with Internet accessibility,which has not been previously available. At the same time it will place theteachers in control of the network in the NetCenter lab premises.The network is designed with a layered approach including an Internetaccess layer, a larger core segment and a distribution layer with aseparated lab network. It also incorporates both a public and a privateserver network, housing servers running e.g. Windows Active Directory,external DNS services, monitoring tools and logging applications. TheInternet access is achieved by peering with SUNET providing a full BGPfeed.This thesis report presents methods, implementations and results involvedin successfully creating the NetCenter ISP as both a lab network and anInternet provider with a few inevitable shortcomings; the most prominentbeing an incomplete Windows Domain setup.
73

The contestation, ambiguities and dilemmas of curriculum development at the Solomon Mahlangu freedom college, 1978 - 1992.

Govender, Rajuvelu January 2011 (has links)
Philosophiae Doctor - PhD / This thesis is an appraisal of curriculum development at the Solomon Mahlangu Freedom College and the Dakawa Development Centre established by the ANC in exile, in Tanzania in 1978 and 1982 respectively. In 1960 the ANC went into exile when it was banned under the Unlawful Organisations Act in the wake of the Sharpeville crisis. The ANC's record in the educational arena from 1912 to 1960 was characterized by reactive responses to state policy as it did not have a structured educational programme that it could offer as an alternative to education for blacks. In the post-1960 period it was faced with a new set of priorities, that is, the huge and complex task of re-organising itself both within South Africa and in exile. In 1978 the ANC established its educational institution, the SOMAFCO High School, in Mazimbu, Tanzania, in the wake of the 1976 uprisings in Soweto and elsewhere in South Africa. In 1980 the project was extended by the establishment of the SOMAFCO Primary School, followed by the Dakawa Development Centre in 1982. Three broad emphases came to the fore when the ANC Education Policy was being formulated in the late 1970s: emphasis on Academic Education; emphasis on Political Education and an emphasis on Polytechnic Education. The ANC Education Department claimed to have formulated a clear and concise education policy in 1978 but sharp debates over the appropriate curriculum for ANC education in exile persisted up to 1992, when the institutions were closed and repatriation to South Africa began The main problem being investigated is why there were such divergent views on the appropriate curriculum for ANC education-in-exile from within the ANC, and in the light of this contestation, what happened in reality to curriculum practice at the institutions. The arguments for Academic, Political and Polytechnic Education are contextualized in the curriculum debates of the times, that is, the zo" century international policy discourse, the African curriculum debates and Apartheid Education in South Africa. This study examines how Academic Education, despite the sharp debates, was institutionalised at the SOMAFCO High School. It also analyses the arguments for and various notions of Political and Polytechnic Education as well as what happened to these in practice at the school. The SOMAFCO Primary School went through three phases of curriculum development. The school opened in 1980 under a 'caretaker' staff and without a structured curriculum. During the second phase 1980-1982 a progressive curriculum was developed by Barbara and Terry Bell. After the Bells resigned in 1982, a conventional academic curriculum was implemented by Dennis September, the new principal. There is debate over why the Dakawa Development Centre was initially opened in 1982. lts objectives were identified at the First Dakawa Seminar in 1982. This study examines curriculum development within its structures: the Vocational Training Centre, the Ruth First Education Orientation Centre and the Raymond Mahlaba Rehabilitation Centre. This study analyses whether the Vocational Training Centre was intended to train students in skills required for the construction of Dakawa or whether it would provide Vocational Education which would lead to the attainment of recognized certification for future employment. It examines whether the Ruth First Education Orientation Centre was an educational facility or a security centre. It also examines the nature of rehabilitation at the Raymond Mahlaba Rehabilitation Centre. The other structures like the farm, small industries and other social facilities are also examined. The study finally traces the relocation of the Dakawa Development Centre to Grahamstown in South Africa.
74

Reactive power management capabilities of Swedish sub-transmission and medium voltage level grid

Tomaszewski, Michal January 2018 (has links)
Rising penetration of renewable energy sources in electric power grids isboth a challenge and an opportunity to optimally utilize the potential of eitherwind or PV energy sources, to stabilize operation of future power systems.Bi-directional ows between distribution and transmission system operatorscause signicant problems with keeping the voltages in the grid within admissiblelimits. This paper contains description of Oland's island mediumandlow-voltage electric power grid, ranging from 0.4 kV to 130 kV in thepurpose of quasi-static analysis of active and reactive power ows in the system.Goal of the analysis is to optimize reactive power exchange at the pointof connection with the mainland grid. In the analyzed grid system, thereis an enormous, 190 % penetration of wind sources. Capacity of the windparks connected to dedicated buses totals to 136.1 MW, that supply up to90.5 MW of load. With industry-wise reactive power capability limits, totalcontribution of wind parks reaches almost 66 MVAr, enabling to compensatedecits and extra surpluses of the reactive power in the grid. Presentedsystem is connected to the mainland's grid through one point of connection,which is simulated as Thevenin equivalent circuit. Main objective of thethesis is to test and analyze viable solutions to minimize reactive power exchangeat the point of connection at Stavlo substation connecting Oland'sand Sweden's electric grid keeping valid all necessary contingencies enforcedby current grid codes applied in Sweden as well as thermal limits of the linesand voltage limits of the system. Furthermore, state of the art of currentreactive power compensation methodologies and most promising techniquesto eciently and eectively control reactive power ow are outlined. Droopcontrol methodologies, with focus on global and local objectives, and smartgrid solutions opportunities are being tested and modeled by the authors andare comprehensively presented in this paper. Moreover, economic costs ofcontrol methods are compared. Analysis of active power losses in the systemas well as cost of implementation of alternative solutions is presented, wheremost nancially viable solutions are outlined, giving brief outlook into futureperspectives and challenges of electric power systems. It is shown that controllabilityof reactive power support by wind turbine generators can enhanceoperation of electric power grids, by keeping the reactive power ow minimizedat the boundary between grids of distribution and transmission systemoperators. Furthermore, results indicate that extra reactive power supportby wind turbine generators can lead to diminishment of active power losses inthe system. Presented system is being modeled in the PSS/E software dedicatedfor power system engineers with use of Python programming languages.Analysis of data was done either in Python or R related environments. Thesiswas written with cooperation between KTH and E.On Energidistribution AB. / Hogre genomslagskraft av förnyelsebara energikällor i elnäteten är bådeen utmaning och möjlighet för att optimalt kunna utnyttja potentialen av vindkraft och PV källor, med avseende på att stabilisera driften av framtida elkraftsystem. Tvåvägsflöden mellan distributionoch transmissionsoperatörer orsakar betydande problem att hålla spänningen i nätet inom tillåtna gränsvärden.Denna uppsats innehåller en beskrivning av Ö lands mellanoch lågspänningsnät,på 0.4 kV till 130 kV i syftet att utföra en kvasistatisk analys av aktiva och reaktiva effektflöden i systemet. Målet med analysen är att optimera det reaktiva effektutbytet i kopplingspunkten med fastlandets nät. I det analyserade systemet, finns det en enorm potential på 190% genomslagskraft av vindkraft. Kapaciteten på vindkraftsparker kopplade till medtagna samlingsskenor i systemet uppgår till 136,1 MW, som tillgodoser upp till 90.5 MW last. Med industrimässigt begränsad reaktiv effektkapabilitet, uppgår vindkraftsparkernas bidrag till nästan 66 MVAr, vilken möjliggör kompensation för underskott och överskott av reaktiv effekt i nätet. Det presenterade systemet är kopplat till fastlandet genom en kopplingspunkt, där fastlandet är simulerat som en Thevenin ekvivalent. Huvudsakliga målet med denna uppsats är att testa och analysera gångbara lösningar för att minimera det reaktiva effektutbytet vid kopplingspunkten i Stävlö, som kopplar ihop Ö land med resterande nät i Sverige, samtidigt som alla nödvändiga villkor enligt nuvarande nätkoder i Sverige bibehålls, liksom termiska gränser för ledningarna och spanningsgränser för systemet. Ytterligare beskrivs den bästa tillgängliga tekniken som finns idag för reaktiv effektkompensation, och de mest lovande teknikerna för att effektivt och verkningsfullt kontrollera reaktiva effektflöden. Droop-kontroll-metodologier, med fokus på globala och lokala tillämpningar, och smarta nät-möjligheter testas och modelleras av författarna och presenterar djupgående i detta arbete. Dessutom jämförs ekonomiska kostnader för olika kontrollmetoder. Analyser av aktiva effektförluster i systemet samt kostnader för implementation av alternativa lösningar presenteras, där de flesta gångbara losningar behandlas, och ger en överskådlig bild av framtida perspektiv och utmaningar i elkraftsystemet. Det visas att vindturbiners kontroll av reaktiv effekt, kan förbättra driften av elnäten, genom att minimera det reaktiva effektflödesutbytet i gränsen mellan distributionoch transmissionsoperatörers nät. Ytterligare pekar resultat på att extra understöd av reaktiv effekt från vindturbiner kan leda till förminskning av aktiva förluster i systemet. Det presenterade systemet modelleras i mjukvaruprogrammet PSS/E dedikerat för elkraftsingenjörer med hjälp av Python. Analys av data gjordes antingen i Pythoneller R-relaterade miljöer. Detta arbete har gjorts tillsam-mans med KTH och E.ON Energidistribution AB.
75

Developing Approaches to Treat Canavan Disease

Wang, Qinzhe 18 October 2017 (has links)
No description available.
76

Firewall Traversal in Mobile IPv6 Networks / Firewall Traversal in Mobile IPv6 Networks

Steinleitner, Niklas 09 October 2008 (has links)
No description available.
77

Quelques défis posés par l'utilisation de protocoles de Gossip dans l'Internet / Gossiping in the wild -- Tackling practical problems faced by gossip protocols when deployed on the Internet

Pace, Alessio 04 October 2011 (has links)
Les systèmes pair-à-pair (P2P) sont aujourd'hui très populaires. Leur utilisation va de la messagerie instantanée au partage de fichiers, en passant par la sauvegarde et le stockage distribué ou encore le streaming video. Parmi les protocoles P2P, les protocoles basés sur le "gossip" sont une famille de protocoles qui a fait l'objet de nombreux travaux de recherche durant la dernière décennie. Les raisons de l'engouement pour les protocoles basés sur le "gossip" sont qu'ils sont considérés robustes, faciles à mettre en oeuvre et qu'ils ont des propriétés de passage à l'échelle intéressantes. Ce sont donc des candidats intéressants dès lors qu'il s'agit de réaliser des systèmes distribués dynamiques à large échelle. Cette thèse considère deux problématiques rencontrées lorsque l'on déploie des protocoles basé sur le "gossip" dans un environnement réel comme l'Internet. La première problématique est la prise en compte des pare-feux (NAT) dans le cadre des protocoles d'échantillonnage basés sur le "gossip". Ces protocoles font l'hypothèse que, a tout moment, chaque noeud est capable de communiquer avec n'importe quel noeud du réseau. Cette hypothèse est fausse dès lors que certains noeuds utilisent des NAT. Nous présentons Nylon, un protocole d'échantillonnage qui fonctionne malgré la présence de NAT. Nylon introduit un faible surcoût pour gérer les NAT et partage équitablement ce surcoût entre les noeuds possédant un NAT et les autres noeuds. La deuxième problématique que nous étudions est la possibilité de limiter la dissémination de messages de type "spam" dans les protocoles de dissémination basés sur le "gossip". Ces protocoles sont en effet des vecteurs idéaux pour diffuser les messages de type "spam" du fait qu'il n'y a pas d'autorité de contrôle permettant de filtrer les messages basés sur leur contenu. Nous proposons FireSpam, un protocole de dissémination basé sur le "gossip" qui permet de limiter la diffusion des messages de type "spam". FireSpam fonctionne par filtrage décentralisé (chaque noeud participe au filtrage). Par ailleurs, il fonctionne malgré la présence d'une fraction de noeuds malicieux (aussi appelés "Byzantins") et malgré la présence de noeuds dits “rationnels” (aussi appelés "égoïstes"). Ces derniers sont prêts à dévier du protocole s'ils ont un intérêt à le faire. / Peer-to-peer (P2P) systems are very popular today. Their usage goes from instant messaging to file sharing, from distributed backup and storage to even live-video streaming. Among P2P protocols, gossip-based protocols are a family of protocols which have been the object of several research works in the last decade. The reasons behind the interest in gossip-based protocols are that they are considered robust, easy to implement, and that they have interesting scalability properties. They are then appealing candidates for implementing dynamic and large-scale distributed systems. This thesis tackles two problems faced by gossip-based protocols when deployed on a practical scenario as the Internet. The first problem is coping with Network Address Translators (NATs) in the context of gossip-based peer sampling protocols. These protocols make the assumption that, at any moment, each node is able to communicate with any other node of the network. This assumption is false when some nodes use NATs. We present Nylon, a peer sampling protocol which works despite the presence of NATs. Nylon introduces a low overhead to cope with NATs and fairly balances this overhead among nodes using a NAT and those which do not. The second problem that we study is the possibility to limit the dissemination of “spam” messages in gossip-based dissemination protocols. These protocols are in fact ideal vectors to spread spam messages due to the fact that there is no central authority in charge of filtering messages based on their content. We propose FireSpam, a gossip-based dissemination protocol which allows limiting the dissemination of “spam” messages. FireSpam implements a decentralized filtering mechanism (each node participates to the filtering). Moreover, it works despite the presence of a fraction of malicious nodes (also called “Byzantine” nodes) and despite the presence of so called “rational” nodes (also called “selfish” nodes). These latters are willing to deviate from the protocol if they have an interest in doing so.
78

Xenotopia: Death and Displacement in the Landscape of Nineteenth-Century American Authorship

Lewis, Darcy Hudelson 12 1900 (has links)
This dissertation is an examination of the interiority of American authorship from 1815–1866, an era of political, social, and economic instability in the United States. Without a well-defined historical narrative or an established literary lineage, writers drew upon death and the American landscape as tropes of unity and identification in an effort to define the nation and its literary future. Instead of representing nationalism or collectivism, however, the authors in this study drew on landscapes and death to mediate the crises of authorial displacement through what I term "xenotopia," strange places wherein a venerated American landscape has been disrupted or defamiliarized and inscribed with death or mourning. As opposed to the idealized settings of utopia or the environmental degradation of dystopia, which reflect the positive or negative social currents of a writer's milieu, xenotopia record the contingencies and potential problems that have not yet played out in a nation in the process of self-definition. Beyond this, however, xenotopia register as an assertion of agency and literary definition, a way to record each writer's individual and psychological experience of authorship while answering the call for a new definition of American literature in an indeterminate and undefined space.
79

Pride and Protest in Letters and Song: Jazz Artists and Writers during the Civil RightsMovement, 1955-1965

Marchbanks, Jack R. 28 June 2018 (has links)
No description available.

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