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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.
591

MECHANISMS OF TGF BETA-INDUCED INHIBITION OF CD1D-MEDIATED ANTIGEN PRESENTATION

Ryan, Jennifer Carrie 18 November 2011 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / CD1d is a cell surface glycolipid that, like Major Histocompatibility Complex (MHC) class I and MHC class II molecules, presents antigen. However, instead of peptides, CD1d presents lipids to Natural Killer (NK) T cells, a subset of T cells that express both NK cell markers and the T cell receptor and produces both T helper (Th) 1 and Th2 cytokines. Our lab focuses on the regulation CD1d-mediated antigen presentation. TGF beta is a known regulator of the immune system, such as controlling MHC class II antigen presentation. Further, TGF beta can activate the mitogen activated protein kinase (MAPK) p38, a known negative regulator of CD1d-mediated antigen presentation. Therefore, we hypothesized that TGF beta would be a negative regulator of CD1d-mediated antigen presentation, and our results showed a decrease in antigen presentation by CD1d in response to TGF beta treatment. However, this inhibition was not through p38 activation, as indicated by the absence of a rescue of CD1d-mediated antigen presentation in, TGF beta-treated, p38 dominant negative-expressing cells. Alternatively, the Smad pathway, the canonical pathway activated by TGF beta, was investigated through a lentivirus shRNA-mediated knockdown of Smad2, Smad3 and Smad4 proteins. Smad2 shRNA-expressing cells showed in an increase in CD1d-mediated antigen presentation, suggesting an inhibitory role for Smad2. In contrast, Smad3 shRNA-expressing cells did not differ from control cells. However, as in the case of Smad2, CD1d+ cells in which Smad4 was knocked down, were substantially better at CD1d-mediated antigen presentation than control cells, suggesting that it also negatively regulates antigen presentation. Overall, these studies demonstrate that the canonical TGF beta/Smad pathway regulates an important part of the host’s innate immune response, vis-à-vis CD1d-mediated antigen presentation.
592

An Investigation into Carbon Flow through the Metabolic Networks of<i>Rhodobacter sphaeroides</i>

Carter, Michael Steven 07 October 2014 (has links)
No description available.
593

La thioredoxine m4 régule les voies photosynthétiques de transfert cyclique d'électrons autour du photosystème l chez les plantes

Courteille, Agathe 25 January 2013 (has links)
Dans les thylakoïdes des végétaux supérieurs, la réaction photochimique de la photosynthèse implique un transfert d’électrons linéaire ayant lieu entre les photosystèmes II et I et aboutit à la production de pouvoir réducteur (NADPH) et d’ATP. En parallèle à ce transfert linéaire, le transfert cyclique d’électrons autour du PS I court-circuite le PS II et fait intervenir distinctement les complexes PGR (PGR5/PGRL1) et NADPH déshydrogénase (NDH). Ces deux voies alternatives permettent la production d’ATP sans accumulation de NADPH dans le stroma et particulièrement en conditions de stress environnemental. Ces voies sont essentielles pour la physiologie de la plante mais leur régulation demeure mal connue. Une hypothèse a été émise quant à leur régulation redox en étudiant plusieurs thiorédoxines chloroplastiques. Des expériences menées in vivo et in vitro sur des mutants d’Arabidopsis, de tabac et de tomate ont mis en évidence le rôle très spécifique de la thiorédoxine m4 dans la régulation négative des voies dépendantes de PGR et NDH. Une stratégie originale a été mise en place pour capturer les cibles putatives de cette thiorédoxine en mutant le site actif de la protéine chez Arabidopsis. Les résultats obtenus ont montré l’existence de plus de 160 cibles potentielles et certaines d’entre elles pourraient être impliquées dans la régulation des voies dépendantes des complexes PGR et NDH. / In plants thylakoids, the photochemical reaction of photosynthesis implies a linear electron flow between photosystems II and I which produces reducing power (NADPH) and ATP. In addition of linear electron flow, the cyclic electron flow around PS I bypasses PS II and involves distinctly the PGR (PGR5/PGRL1) and the NADPH dehydrogenase (NDH) complexes. These two alternative pathways lead to the production of ATP without accumulation of NADPH in the stroma especially under environmental stress conditions. Both pathways are essential for the plant physiology but their regulation remains unclear. An assumption concerning a redox regulation has been considered by surveying several chloroplastic thioredoxins. In vivo and in vitro studies of Arabidopsis, tobacco and tomato mutants revealed that the m4 thioredoxin plays a very specific role in the down-regulation of the PGR and NDH dependant pathways. An original strategy to capture putative targets of this thioredoxin has been established by mutating the active site of the protein in Arabidopsis. The results showed the existence of more than 160 potential targets and some of them could be involved in the regulation of PGR and NDH dependant pathways.
594

Affect and Performance: A Multilevel Analysis of Moderators and Mediators

Elisha Frederiks Unknown Date (has links)
This thesis examined the intra-individual relationship between state affect and task performance, with an emphasis on a) the moderating effects of trait affect and task difficulty; and b) the mediating effects of cognitive and affective regulation. Theory and empirical research from the emotion, motivation, and personality literatures was integrated to develop a multilevel model of states, traits, and situational factors as predictors of task performance. Data from five studies were analysed using single- and multi-level techniques to test the hypothesised model of relationships. The findings are reported within three manuscripts, which comprise the body of this thesis. Manuscript 1 presents validation evidence for the psychometric instruments used to measure the self-regulatory components of the model. Three studies (N = 758) were conducted to examine the nomological network of cognitive and affective regulation. In parallel, two new self-report scales were developed to operationalise these constructs within a repeated measures paradigm. The three studies demonstrated that the new cognitive and affective regulation scales were uniquely associated with other self-regulatory, personality, affective and achievement variables at the intra-individual and inter-individual levels. Study 1 provided evidence for the unidimensionality, internal consistency, and construct validity of each scale. Study 2 replicated and extended construct validity evidence using a different sample and performance domain. Study 3 established the utility of each scale for assessing intra-individual variability in cognitive and affective regulation, and their ability to predict performance within individuals. In sum, the three studies suggested that the new measures of cognitive and affective regulation were psychometrically adequate for use in model testing. Manuscripts 2 and 3 tested the intra-individual relationship between state affect and task performance, with a focus on the moderating effects of trait affect and task difficulty (Manuscript 2), and the mediating effects of cognitive and affective regulation (Manuscript 3). Each manuscript analysed different portions of data from two laboratory experiments (N = 182). In each experiment, participants performed multiple trials of an air-traffic control simulation that varied in task difficulty at the inter-individual (Study 4) or intra-individual (Study 5) level. Trait positive and negative affect were measured before the task, whereas state positive and negative affect, cognitive and affective regulation, and task performance were measured at repeated intervals over practice. In Manuscript 2, hierarchical linear modelling demonstrated that state positive affect was positively related, whereas state negative affect was negatively related, to task performance at the intra-individual level of analysis. As hypothesised, the strength of these affect-performance relationships was significantly moderated by trait affect and task difficulty. In both studies, the positive intra-individual relationship between state positive affect and performance was stronger for individuals with high (versus low) trait positive affect, particularly when task difficulty was high (versus low). In contrast, the negative intra-individual relationship between state negative affect and performance only emerged for individuals with low (versus high) trait negative affect, regardless of the level of task difficulty. In Study 4, the intra-individual relationship between state negative affect and task performance was also more pronounced when task difficulty was high (versus low). In Manuscript 3, multilevel multiple-mediation modelling demonstrated that cognitive regulation significantly mediated the intra-individual relationship between state positive affect and performance in both studies, alongside the intra-individual relationship between state negative affect and performance in Study 4. Unexpectedly, affective regulation failed to mediate either of these affect-performance relationships. However, state positive affect was positively related to affective regulation in both studies, whereas state negative affect was positively related to affective regulation in Study 5. Overall, this thesis makes theoretical, empirical and methodological contributions to understanding how affect relates to performance at the intra-individual level of analysis; and for whom, when, and why these relationships emerge. Within a multilevel framework, it integrates interdisciplinary perspectives to identify the affective determinants of performance from two levels of analysis. The results demonstrate that state positive and negative affect can differentially predict intra-individual variability in task performance, and that these effects may a) depend on trait affect and task difficulty; and b) be partially explained by cognitive regulation. These findings emphasise the importance of adopting a multilevel, repeated measures paradigm to examine how affective states, traits, and task demands interactively predict task performance. There is scope for extending this research further by investigating a broader range of moderating and mediating constructs. Practical implications and directions for future research are discussed.
595

Affect and Performance: A Multilevel Analysis of Moderators and Mediators

Elisha Frederiks Unknown Date (has links)
This thesis examined the intra-individual relationship between state affect and task performance, with an emphasis on a) the moderating effects of trait affect and task difficulty; and b) the mediating effects of cognitive and affective regulation. Theory and empirical research from the emotion, motivation, and personality literatures was integrated to develop a multilevel model of states, traits, and situational factors as predictors of task performance. Data from five studies were analysed using single- and multi-level techniques to test the hypothesised model of relationships. The findings are reported within three manuscripts, which comprise the body of this thesis. Manuscript 1 presents validation evidence for the psychometric instruments used to measure the self-regulatory components of the model. Three studies (N = 758) were conducted to examine the nomological network of cognitive and affective regulation. In parallel, two new self-report scales were developed to operationalise these constructs within a repeated measures paradigm. The three studies demonstrated that the new cognitive and affective regulation scales were uniquely associated with other self-regulatory, personality, affective and achievement variables at the intra-individual and inter-individual levels. Study 1 provided evidence for the unidimensionality, internal consistency, and construct validity of each scale. Study 2 replicated and extended construct validity evidence using a different sample and performance domain. Study 3 established the utility of each scale for assessing intra-individual variability in cognitive and affective regulation, and their ability to predict performance within individuals. In sum, the three studies suggested that the new measures of cognitive and affective regulation were psychometrically adequate for use in model testing. Manuscripts 2 and 3 tested the intra-individual relationship between state affect and task performance, with a focus on the moderating effects of trait affect and task difficulty (Manuscript 2), and the mediating effects of cognitive and affective regulation (Manuscript 3). Each manuscript analysed different portions of data from two laboratory experiments (N = 182). In each experiment, participants performed multiple trials of an air-traffic control simulation that varied in task difficulty at the inter-individual (Study 4) or intra-individual (Study 5) level. Trait positive and negative affect were measured before the task, whereas state positive and negative affect, cognitive and affective regulation, and task performance were measured at repeated intervals over practice. In Manuscript 2, hierarchical linear modelling demonstrated that state positive affect was positively related, whereas state negative affect was negatively related, to task performance at the intra-individual level of analysis. As hypothesised, the strength of these affect-performance relationships was significantly moderated by trait affect and task difficulty. In both studies, the positive intra-individual relationship between state positive affect and performance was stronger for individuals with high (versus low) trait positive affect, particularly when task difficulty was high (versus low). In contrast, the negative intra-individual relationship between state negative affect and performance only emerged for individuals with low (versus high) trait negative affect, regardless of the level of task difficulty. In Study 4, the intra-individual relationship between state negative affect and task performance was also more pronounced when task difficulty was high (versus low). In Manuscript 3, multilevel multiple-mediation modelling demonstrated that cognitive regulation significantly mediated the intra-individual relationship between state positive affect and performance in both studies, alongside the intra-individual relationship between state negative affect and performance in Study 4. Unexpectedly, affective regulation failed to mediate either of these affect-performance relationships. However, state positive affect was positively related to affective regulation in both studies, whereas state negative affect was positively related to affective regulation in Study 5. Overall, this thesis makes theoretical, empirical and methodological contributions to understanding how affect relates to performance at the intra-individual level of analysis; and for whom, when, and why these relationships emerge. Within a multilevel framework, it integrates interdisciplinary perspectives to identify the affective determinants of performance from two levels of analysis. The results demonstrate that state positive and negative affect can differentially predict intra-individual variability in task performance, and that these effects may a) depend on trait affect and task difficulty; and b) be partially explained by cognitive regulation. These findings emphasise the importance of adopting a multilevel, repeated measures paradigm to examine how affective states, traits, and task demands interactively predict task performance. There is scope for extending this research further by investigating a broader range of moderating and mediating constructs. Practical implications and directions for future research are discussed.
596

Regulação de serviços públicos: a atuação da agerba no gás canalizado

Villalba, Érica Torre January 2007 (has links)
p. 1 - 107 / Submitted by Santiago Fabio (fabio.ssantiago@hotmail.com) on 2013-02-18T20:11:07Z No. of bitstreams: 1 7777.pdf: 1680836 bytes, checksum: 52eee00cf9c8d34c6ddf28db32daa7b4 (MD5) / Approved for entry into archive by Fatima Cleômenis Botelho Maria (botelho@ufba.br) on 2013-02-19T16:31:51Z (GMT) No. of bitstreams: 1 7777.pdf: 1680836 bytes, checksum: 52eee00cf9c8d34c6ddf28db32daa7b4 (MD5) / Made available in DSpace on 2013-02-19T16:31:51Z (GMT). No. of bitstreams: 1 7777.pdf: 1680836 bytes, checksum: 52eee00cf9c8d34c6ddf28db32daa7b4 (MD5) Previous issue date: 2007 / Este trabalho propôs-se a analisar a regulação de serviços públicos de gás natural canalizado, na Bahia, a partir da atuação da agência reguladora estadual, procurando comparar as ações dirigidas ao acompanhamento das tarifas praticadas com aquelas voltadas à qualidade da prestação dos serviços, além de descrever a relação existente entre esta agência, o Estado da Bahia e a concessionária prestadora dos serviços de gás canalizado. Empreendeu-se pesquisa descritiva de cunho qualitativo, por meio de estudo de caso do tipo organizacional. Elegeu-se como objeto empírico o desempenho, no gás canalizado, da Agência Estadual de Regulação de Serviços Públicos de Energia, Transportes e Comunicações da Bahia – AGERBA, no período de 2004 a 2006. Além da revisão de literatura que buscou aprofundamento sobre o tema, foram realizadas pesquisa documental e entrevistas estruturadas, para a coleta de dados, assim como analisado o material coletado e feita a articulação entre os teóricos estudados e os resultados obtidos na investigação. As agências reguladoras surgiram, no Brasil, na década de noventa do século passado, com o objetivo de favorecerem um ambiente institucional propício aos investimentos privados e com a finalidade de fiscalizarem a qualidade dos serviços públicos, intermediando, portanto, os interesses dos usuários, das empresas prestadoras e do poder concedente. Como resultado, no tocante ao gás canalizado, verificou-se que, como mediadora dos interesses do Estado, usuários e concessionária, a relação entre a agência e esses atores se dá de forma desigual, diferentemente do que preceitua a teoria da regulação. O estudo do caso demonstrou que a atuação da AGERBA limita-se, basicamente, à regulação econômica através do acompanhamento das tarifas, deixando de atender, com igual desempenho, à regulação da qualidade da prestação dos serviços e à regulação social. / Salvador
597

Samoregulace v reklamě vs. právní úprava reklamy v ČR / Self-regulation of advertising vs. legal regulation of advertising in the Czech Republic

Slaný, Miroslav January 2011 (has links)
The aim of this thesis is to describe and explain legal and ethical regulation of advertising in the Czech Republic. It also aims to analyze relevant legislation in the Czech legal system in more detail and compare it to the means of self-regulation. We shall refer to their advantages, disadvantages and the interconnection of both systems.
598

Regulating self, others’ and group motivation in online collaboration

Bakhtiar, Aishah 10 December 2019 (has links)
Collaboration is a sought-after competency in the 21st-century knowledge economy in which the value of collective ideas and innovations are emphasized. Educational institutions have a role to play in preparing graduates to work well in collaborative teams. However, collaborating with peers is often received with mixed feelings. Students raise concerns about group members’ motivation and engagement, in anticipation of unsatisfactory social and learning outcomes. Facing motivation challenges in collaboration is a common occurrence, but limited research examines how students working in groups manage motivation challenges in that context. The purpose of this multi-paper dissertation was to examine undergraduate students’ regulatory responses to motivation challenges during online collaborations. Three empirical studies comprising this dissertation examined: the interrelated process involved in groups’ regulation of the socio-emotional aspect of collaboration (Bakhtiar, Webster, & Hadwin), the tactics and strategies students enacted in response to salient motivation challenges (Bakhtiar, Hadwin, & Järvenoja, 2019), and the dynamic interplay between individual- and group-level regulation during motivationally challenging situations (Bakhtiar & Hadwin, 2019). The first study was a comparative case analysis between two groups with contrasting socio-emotional climates. Groups’ self-report and observational data (collected before, during, and after a 90-minute collaboration) were examined in relation to the COPES-model of regulation to identify the similarities and differences between groups’ prevailing conditions, operations, products, evaluations, and standards in regulation. In Study 2, group members’ perceptions of motivation challenges that emerged during planning, early, and towards the end of a semester-long collaborative project were explored. Students’ open descriptions of strategies adopted in response to their salient motivation challenges were qualitatively coded. Study 3 was another comparative case analysis between two groups, who experienced high levels of motivation challenges during collaboration but achieved contrasting group perceptions of team learning productivity. The groups’ use of self-, co-, and socially shared-regulation of motivation in three collaborative sessions were examined and contextualized using group members’ self-reports and log data. Findings across the three studies were discussed in terms of their contributions to the COPES scripts of regulating motivation in collaboration, to develop a catalogue of individual and social strategies for regulating motivation, and to identify adaptive forms of motivation regulation in collaboration. Overall, groups that experienced a more positive outcome regarding motivation regulation had group members who (a) were more prepared going into the task, (b) engaged in proactive forms of regulation, (c) more metacognitively attuned to individuals’ and groups’ diverse needs and challenges, (d) used diverse types of strategies, and (e) regulated each other in a positive and encouraging way. Future directions are discussed in terms of examining the metacognitive information students base on when regulating motivation individually, for others, and as a team, as well as designing tools and instructions to support motivation in collaboration. / Graduate
599

Känsloreglering hos Elitidrottare : Känslor elitidrottare upplever timmen innan en viktig tävling och hur de hanteras / Elite athletes’ emotion regulating strategies : Feelings an elite athlete experience in the hour before an important competition and how those feelings are handled

Alfvén, Lena, Lagerberg, Maria January 2020 (has links)
Syftet med studien var att utifrån Gross (2007) teori undersöka känsloregleringsstrategier hos elitidrottare. Studiens frågeställning var: Vilka känslor upplever elitidrottaren timmen innan en viktig tävling och hur hanterar idrottaren de uppkomna känslorna? Studien omfattade nio elitidrottare inom individuella idrotter. Datainsamlingen genomfördes med semistrukturerade intervjuer som transkriberades och analyserades via en innehållsanalys. Analysen resulterade i sex teman med respektive två till tre subteman. De sex huvudteman var distraktion, självprat/peptalk, social strategi, struktur, uppmärksamhetsfokus och visualisering. Elitidrottarna sa samstämmigt att de upplevde känslor timmen före start i en viktig tävling och de gav uttryck för att de använde sig av känsloreglerande strategier. Dessa strategier användes ofta omedvetet. Att medvetandegöra känsloreglerande strategier kan bidra till att skapa möjligheter till en bättre tävlingsprestation. / The purpose of the study was, based on Gross’ (2007) theory, to investigate elite athletes’ emotion regulating strategies. The issue posed in the Study was the following: What feelings does an elite athlete experience in the hour before an important competition and how does the athlete handle those feelings? The study pertained to nine elite athletes in individual athletic disciplines. The compilation of data was performed through semi-structured interviews which were transcribed and analysed using a content analysis. The analysis resulted in six categories with 2-3 sub-categories. The six main categories were distraction, self-talk/pep-talk, social strategy, structure, attention focus and visualisation. The elite athletes conclusively stated that they did experience feelings during the hour just before an important competition and they gave the impression that they used emotion regulating strategies. These strategies were often used sub- consciously. Raising awareness of emotion regulating strategies can contribute to creating possibilities for enhanced performance.
600

EFFECTS OF AIRWAY SUCTION ON FUNCTIONAL RESIDUAL CAPACITY AND ARTERIAL OXYGEN TENSION IN NORMAL DOGS.

Muenchau, Theresa Ann. January 1983 (has links)
No description available.

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