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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.
151

A New Special Protection Scheme for Power System Controlled Separation

Maram, Sandeep 06 February 2007 (has links)
A new power system controlled separation scheme is proposed to prevent the propagation of cascading failures across a transmission network should it undergoes a major disturbance, thereby reducing the possibility of a large-scale blackout. This scheme is developed based on a set of conjectures, which state the following: (i) the locations of out-of-step operations are independent of the severity and the location of the initial faults; (ii) these out-of-step operations occur sequentially over a sufficiently long duration so that relay blocking and transfer tripping can take place to minimize the load-generation imbalance in the formed islands. To verify these conjectures, extensive dynamic stability simulations are executed on a 30-bus and a 517-bus system, which exhibit characteristics suitable for this study. Furthermore, we verify that these out-of-step operations do depend on the prevailing system topology and the operating conditions. / Master of Science
152

Magnetism in Ni80Fe20 and Ni80Fe20/NiO Nano-stripes

Mirza, Mueed 22 August 2012 (has links)
Ni80Fe20 and Ni80Fe20/NiO films and nano-stripes were characterized magnetically through AC and DC susceptibility measurements, and hysteresis loops as a function of field and temperature. While the near-pattern films were characterized in the in-plane configuration only, the nano-stripes were characterized in parallel, transverse and the perpendicular field configurations. The effects of the constrained geometry on the coercivity, exchange bias field, and the superparamagnetic blocking temperature were studied. It was determined that the coercivity, exchange bias field and the superparamagnetic blocking temperature can be controlled, not only by using a patterned media instead of a plane film, but also by the orientation of that pattern.
153

Magnetism in Ni80Fe20 and Ni80Fe20/NiO Nano-stripes

Mirza, Mueed 22 August 2012 (has links)
Ni80Fe20 and Ni80Fe20/NiO films and nano-stripes were characterized magnetically through AC and DC susceptibility measurements, and hysteresis loops as a function of field and temperature. While the near-pattern films were characterized in the in-plane configuration only, the nano-stripes were characterized in parallel, transverse and the perpendicular field configurations. The effects of the constrained geometry on the coercivity, exchange bias field, and the superparamagnetic blocking temperature were studied. It was determined that the coercivity, exchange bias field and the superparamagnetic blocking temperature can be controlled, not only by using a patterned media instead of a plane film, but also by the orientation of that pattern.
154

Nätverksoptimering med öppen källkod : En studie om nätverksoptimering för sjöfarten

Deshayes, Dan, Sedvallsson, Simon January 1900 (has links)
Detta examensarbete handlar om hur datatrafik över en satellitlänk kan optimeras för att minska laddningstider och överförd datamängd. Syftet med studien är att undersöka i vilken omfattning datatrafik mellan fartyg och land via satellitlänk kan styras så att trafiken blir effektivare. Genom att använda DNS-mellanlagring, mellanlagring av webbsidor samt annonsblockering med pfSense som plattform har examensarbetet utfört experiment emot olika hemsidor och mätt laddningstid samt överförd datamängd. Resultatet visade att det fanns stora möjligheter att optimera nätverkstrafiken och de uppmätta resultaten visade på en minskning av datamängden med 94% och laddningstiderna med 67%. / The thesis describes how network traffic transmitted via a satellite link can be optimized in order to reduce loading times and transmitted data. The purpose with this study has been to determine what methods are available to control and reduce the amount of data transmitted through a network and how this data is affected. By applying the practice of DNS caching, web caching and ad blocking with the use of pfSense as a platform the study has performed experiments targeting different web sites and measured the loading times and amount of transmitted data. The results showed good possibilities to optimize the network traffic and the measured values indicated a reduction of the network traffic of up to 94% and loading times with 67%.
155

AtZDP, a Plant 3' DNA Phosphatase, Involved in DNA Repair

Valsecchi, Isabel January 2008 (has links)
<p>DNA bases can be modified by endogenous agents (e.g. oxidized by products of respiration and photosynthesis or methylated by gene silencing processes) as well as by environmental agents (e.g. oxidized by UV light). In the process of removing modified bases, a 3’-phosphate group is sometimes left in the resulting gap, and has to be removed since it blocks the incorporation of a new nucleotide by DNA polymerase. The aim of this thesis was the characterization of AtZDP, a plant enzyme with a DNA 3’-phosphatase activity.</p><p>By homologous modeling, the existence of four domains was predicted in AtZDP, three independent zinc-finger and one DNA 3’-phosphatase domains. AtZDP was found to be localized in the nucleus by bimolecular fluorescence complementation. Western blotting analysis showed that the enzyme was ubiquitously expressed in plant tissues.</p><p>AtZDP was found in a 600,000 molecular-weight protein complex by gel chromatography and glycerol gradient sedimentation centrifugation. The fractions containing AtZDP in the complex displayed 3’-DNA phosphatase activity as shown by desphosphorylation of a DNA oligonucleotide with a 3’-phosphate terminus. Also fractions of the gel chromatography corresponding to lower molecular weight showed 3’-DNA phosphatase activity, but antibodies against AtZDP did not recognize this fraction inferring that in plants, at least another protein with similar activity exists.</p><p>In mammals, polynucleotide kinase, an enzyme with the same activity phosphatase activity as AtZDP, is involved in single-strand and double-strand repair pathways. To elucidate if AtZDP could be part of similar pathways, different double strand and single-strand oligonucleotides with 3’-phosphate termini were separately incubated with AtZDP. All substrates were dephosphorylated by AtZDP, assuming that this enzyme could potentially be involved in double-strand DNA repair. </p><p>A double-strand oligonucleotide containing a one-bp gap with a 3’-phosphate terminus was repaired by a leaf protein extract. The activities of a 3’-DNA phosphatase, a flap 5’ to 3’ endonuclease-like, a DNA polymerase and a DNA ligase were observed. The presence of these enzymes revealed that these damages are in plants predominantly repaired by long-patch base excision repair.</p>
156

Pre-clinical development of viral vectored transmission-blocking malaria vaccines

Kapulu, Melissa Chola January 2014 (has links)
Malaria transmission-blocking vaccine candidate antigens have been developed to induce antibodies using different delivery systems, mainly protein-in-adjuvant formulations, independently in various laboratories giving varied transmission-blocking activity (TBA). However, only one candidate antigen has been tested in clinical trials. In order to advance the most efficacious target(s) for possible clinical development, a rank order of the leading antigens based on TBA in a head-to-head comparison using a single delivery platform was made. Candidate antigens, AnAPN1, PfsHAP2, Pfs230-C, Pfs25, and Pfs48/45 (with or without N-glycosylation site substitution), were generated as recombinant viral-vectored vaccines using simian adenovirus and modified vaccinia Ankara and administered to mice in a heterologous prime-boost regimen. Vaccine-induced antibody responses were induced to all except PfsHAP2 were maintained up to ten and a half months post-boost. TBA was assessed at the peak response against Plasmodium falciparum NF54 laboratory strain and African field isolates by ex vivo membrane feeding assays in Anopheles stephensi and A. gambiae respectively. Antibodies to three antigens [Pfs230-C, Pfs25 and Pfs48/45+<sub>NGln</sub>] had TBA against P. falciparum NF54, and those against Pfs230-C and Pfs25 consistently showed efficacy regardless of the parasite exposure in both mosquito species. Further analysis of antibody responses to these two candidate antigens showed concentration-dependent efficacy against P. falciparum field isolates. In a rabbit study, responses to Pfs230-C, Pfs25 and Pfs48/45+<sub>NGln</sub> also showed IgG concentration-dependent efficacy. To assess TBA against AnAPN1, antibody responses to three fragments were tested. TBA was observed only against N-terminal 135 amino acid fragment. Pfs230-C and Pfs25 were generated as fusion vaccines using either a self-cleaving or glycine-proline linker sequence. Comparable antibody responses were induced between the two fusion strategies that had synergistic effects at inhibiting P. falciparum NF54 development in A. stephensi.
157

The Director's Presence

Wurth, Paul Stephen 01 January 2008 (has links)
This text is partial record and narrative of the process and productions of Orphans by Lyle Kessler that opened on March 29th 2007 for a four day run ending on April 1st, The Pillowman by Martin McDonagh that opened October 28th 2007 for a three day run ending on October 30th, and Terra Nova by Ted Tally that opened on February 21st 2008 for a four day run ending on February 24th. The majority of the text follows the three shows from Spring 2007, Fall 2007, to Spring 2008, focusing on the process of direction of each production. Incorporated in the writing are the experiences, lessons, and complications that arose while directing the three shows. The text contains several notes on directing, acting, collaboration, choreography, casting, rehearsal and different perspectives on the creative process of the productions: all combined create an aesthetic inherent in the author's three years of study at the Virginia Commonwealth University Theatre Pedagogy Program with an emphasis in Acting and Directing.
158

Propriétés antiparasitaires des benzyl-ménadiones : étude de leur mécanisme d'action et de leur potentiel à bloquer la transmission des parasites du paludisme au moustique vecteur Anopheles gambiae / Antiparasitic benzyl-menadiones : a study of their mode of action and of their efficacy to block transmission of the malaria parasite to the Anopheles gambiae mosquito vector

Goetz, Alice-Anne 28 November 2016 (has links)
La plasmodione est une benzylmenadione (bMD) qui a été désignée comme inhibiteur subversif de flavoenzymes. Ces enzymes utilisent FAD comme co-facteur et sont impliquées dans de nombreux processus biologiques, et notamment dans le maintien de l’homéostasie redox par les systèmes thiorédoxine et glutathion. La plasmodione présente une forte activité contre P. falciparum in vitro, elle est actif sur tous les stades asexués, préférentiellement sur les stades anneaux, avec une vitesse d’élimination des parasites très rapide. Mon objectif a été de tester sa capacité à bloquer la transmission du parasite murin au moustique et de contribuer à déterminer son mode d’action. Pour ce faire, j’ai dans un premier temps mis au point de nouveaux protocoles. Mes résultats ont démontré que (i) la plasmodione réduit le développement du parasite in vivo et limite la transmission du parasite au moustique en agissant sur tous les stades parasitaires sexués infectieux pour le moustique ; (ii) qu’un dérivé de la même famille, plus soluble, est beaucoup plus efficace, notamment sur les stades sexués et la transmission ; (iii) que lorsqu’ils sont délivrés directement au moustique, il n’y a aucun effet du bleu de méthylène ou de la plasmodione sur la survie des moustique ; (iv) enfin en utilisant des parasites invalidés pour la GR, la GS, la γGCS ou la GluPho, mes résultats suggèrent que le modèle d’action proposé des bMDs est à revoir, et que d’autres flavoenzymes pourraient être la cible. / Plasmodione is a benzylmenadione, synthetized as a flavoenzyme inhibitor. These enzymes use FAD as a cofactor and are involved in numerous biologic processes, including the regulation of the redox equilibrium through thioredoxin and glutathione metabolisms. Plasmodione is very efficient in vitro against all stages of the human parasite P. falciparum, especially on ring stages, and is a fast killer. The aims of my PhD were to monitor the ability of Plasmodione to block parasite transmission to mosquitoes and to characterized its mode of action. For that, I had to implement new protocols. My results showed (i) that Plasmodione decrease both the parasite development in vivo and its transmission to mosquitoes while acting on every sexual stage infectious for the mosquito. (ii) A derivative from the same chemical family, more soluble, is more efficient than Plasmodione, especially on asexual stages and on transmission. (iii) When compounds are directly deliver into mosquitoes, neither methylene blue or Plasmodione have an effect on the survival. (iv) Finally, the use of knock out parasites for the GR, GS, γGCS or GluPho genes suggest that the proposed mode of action of the benzylmenadiones has to be corrected and other flavoenzymes could be targeted rather than GR.
159

Mudando a visão: videolaringoscopia como opção para intubações no departamento de emergência pediátrica / Changing the view: video laryngoscopy as option for intubations at the pediatric emergency department

Couto, Thomaz Bittencourt 05 February 2019 (has links)
INTRODUÇÃO: Intubação traqueal é habilidade essencial para o atendimento de emergências, porém, na população pediátrica é procedimento menos frequente e mais difícil que na população adulta. A intubação apresenta em situações controladas uma baixa taxa de complicações. No entanto, no departamento de emergência pediátrica é procedimento de maior risco. O uso de videolaringoscopia é uma alternativa a laringoscopia direta. Há escassa evidência do uso sistemático do videolaringoscópio na emergência pediátrica. Nossa hipótese é que o uso do videolaringoscópio propiciará maior sucesso em intubação traqueal na primeira tentativa, e que diminuirá complicações da intubação traqueal. OBJETIVOS: Comparar as taxas de sucesso de intubação traqueal entre pacientes pediátricos maiores de um ano intubados usando videolaringoscopia ou laringoscopia direta. Comparar a frequência de eventos associados à intubação traqueal e presença de queda da saturação de oxigênio entre estes pacientes. MÉTODOS: Estudo clínico prospectivo de intervenção, não randomizado, aberto, com controle de série histórica. Realizado em departamento de emergência pediátrica terciário. Foram avaliados registros de intubação de pacientes maiores de um ano, por 23 meses, entre julho de 2016 e maio de 2018, com 50 intubações com videolaringoscópio (grupo VL), comparados com série histórica de 5 anos, entre julho de 2005 e dezembro de 2010, com 141 intubações com laringoscopia direta (grupo LD). RESULTADOS: A taxa de sucesso em primeira tentativa no grupo VL foi 68% (34/50), comparada com 37,6% (53/141) do grupo LD (p < 0,01). Houve menor proporção de eventos associados à intubação traqueal no grupo VL com 31,3% (15/50), versus 67,8% (97/141) no grupo LD (p < 0,01), não houve diferenças significantes na queda de saturação. CONCLUSÕES: Videolaringoscopia apresentou maior sucesso em primeira tentativa e menor taxa de complicações. Esse resultado sugere que videolaringoscópio pode ser considerado como primeira escolha nas intubações de pacientes pediátricos no departamento de emergência / INTRODUCTION: Tracheal intubation is an essential skill to treat emergencies, but it is a less frequent and more difficult procedure in the pediatric than in the adult population. Intubation presents a low rate of complications in controlled situations. However, in the pediatric emergency department is a higher risk procedure. The use of video laryngoscopy is an alternative to direct laryngoscopy. There is scant evidence of the systematic use of video laryngoscopes in pediatric emergency. Our hypothesis is that the use of video laryngoscope will lead to greater success in tracheal intubation in the first attempt, and will reduce complications of tracheal intubation. OBJECTIVES: To compare the success rates of tracheal intubation among pediatric patients over one year old intubated with video laryngoscopy or direct laryngoscopy. To compare the frequency of tracheal intubation associated events and decreased oxygen saturation among these patients. METHODS: This was a prospective, non-randomized, open-label clinical study with historical control. Study conducted in a pediatric tertiary emergency department. We compared intubation records of children over one year old, for 23 months, between July 2016 and May 2018, with 50 video laryngoscope intubations (VL group), with a 5-year historical series between July 2005 and December 2010, with 141 intubations with direct laryngoscopy (DL group). RESULTS: The first pass success rate in the VL group was 68% (34/50), compared with 37.6% (53/141) DL group (p < 0.01). There was a lower proportion of tracheal intubation associated events in the VL group, with 31.3% (15/50) versus 67.8% (97/141) in the DL group (p < 0.01), there were no significant differences in desaturation. CONCLUSIONS: Video laryngoscopy was more successful in the first intubation attempt and had lower rate of complications. This result suggests that video laryngoscope may be the first choice device in pediatric intubations in the emergency department
160

Efeitos da combinação de estímulos olfativos e auditivos em treino discriminativo de um procedimento de bloqueio de estímulos em ratos / Olfactory and auditory stimuli combinations effects on a discriminative training of a stimuli blocking procedure in rats

Carneiro, Francisco Andeson Gonçalves 24 July 2014 (has links)
O uso de estímulos olfativos em estudos de discriminação simples e complexa em ratos tem fornecido dados relevantes à área de controle de estímulos porque esta modalidade de estímulo é mais saliente à espécie do que as comumente utilizadas. O objetivo deste estudo foi investigar o efeito da combinação entre as modalidades de estímulo olfativa e auditiva sobre o responder discriminado em um procedimento de bloqueio de estímulos em ratos. Quatro ratos machos Wistar (Rattus norvegicus) foram treinados em três tarefas de discriminação de acordo com o delineamento de bloqueio de estímulos. Na Fase I discriminação prévia, dois ratos foram treinados usando estímulos auditivos (A+/A-) e outros dois usando estímulos olfativos (B+/B-) como S+/S-. Na Fase II discriminação de estímulo composto, um estímulo composto (A+B+/A-B-) foi usado como S+/S- e na Fase III discriminação pós-composto, os estímulos usados na Fase I foram removidos do composto e o treino continuou com os estímulos restantes. Em seguida, foram treinados em fases adicionais: IV - (mesmo treino da Fase II), V (mesmo treino da Fase III) e Fase VI em duas etapas primeira, treino com A+/A- e B+/B- na mesma sessão sem configuração de estímulo composto e segunda, treino de competição de dicas A+B- e B+A-. Todas as fases foram realizadas a partir de um procedimento Go/No-Go. Respostas em esquema de razão fixa três na condição S+ (A+, A+B+ e B+) foram consequenciadas com acesso à solução de sacarose e resposta na condição S- (A-, A-B- e B-) resultou em timeout de 2s após o final da tentativa. Não foi programada consequência específica para o não responder. Para todas as fases o critério de aquisição foi 90% ou mais de índice discriminativo. Na Fase I os resultados mostraram uma aquisição mais rápida do responder discriminado com estímulos olfativos. Os dados das Fases II e III indicaram que houve ocorrência de bloqueio de estímulos para todos os sujeitos, independente da ordem de treino com as modalidades de estímulos. As Fases IV e V indicaram uma replicação do fenômeno de bloqueio apesar do treino realizado na Fase III. A Fase VI sugeriu que o responder discriminado se diferenciou segundo o tipo de configuração de estímulo e que a repetição de bloqueio foi produzida pela discriminação prévia. Os resultados do estudo indicaram que a modalidade de estímulo foi determinante na aquisição de discriminação, mas não para bloqueio de estímulos, discordando da ideia de que odores não são bloqueados quando usados em estímulo composto em ratos e mostrando também que a saliência dos estímulos olfativos foi modulada pela discriminação prévia com outra modalidade / Use of olfactory stimuli in simple and complex discrimination studies with rats has produced important data to stimuli controls area because this stimulus modality is more salient than others usually used. The objective of this study was to investigate combinations effects between olfactory and auditory stimuli modalities on discriminative responding to stimuli blocking design. Four male Wistar rats (Rattus norvegicus) were trained in three discriminative tasks according to the stimuli blocking design. In Phase I prior discrimination, two rats were trained using auditory stimuli (A+/A-) and two rats using olfactory stimuli (B+/B-) as S+/S-. On Phase II compound stimulus discrimination, a compound stimuli (A+B+/A-B-) were used as S+/S- and in Phase III post-compound stimulus discrimination, the stimuli used on Phase I were remove from the compound. After discriminative training, subjects were trained on additional phases: Phase IV (same training Phase II), Phase V (same training Phase III) and Phase VI with two stages: first - A+/A- and B+/B- training presented in the same session without stimulus compound configuration, second - cue competition training (A+B- and B+A-).Discriminative training was carried under a Go/No-Go procedure. Responses on a fixed-ratio three schedule was reinforced by access to a sucrose solution when S+ (A+, A+B+ and B+) was presented and responding in S- (A-, A-B- and B-) resulted in 2s-timeout after trials ending. No consequence was programmed to non-responding. The acquisition criterion was a 90% or more discriminative index. Phase I data showed a discriminative responding acquisition faster with olfactory stimuli compared to auditory stimuli. Phases II and III data revealed stimuli blocking for all subjects regardless of training order with stimulus modalities. Phases IV and V showed a replication of stimuli blocking despite the training occurred on Phase III. Phase VI indicated that discriminative responding differed by type stimulus configuration presented and that stimulus blocking replication was produced by prior discrimination. Thus, results indicated that stimuli sensory modality was relevant for discriminative responding but not for blocking, disagreeing from the idea that odors are not blocked when it are used in compound stimulus in rat and showing also that olfactory stimulus saliency can be changed by prior discrimination training by other modality

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