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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.
181

\"Constantes de acoplamento a partir das regras de soma da QCD\" / The coupling constants in QCD sum rules

Rômulo Rodrigues da Silva 29 June 2005 (has links)
Usamos as regras de soma da QCD para obter a massa dos pentaquarks \" \'teta\' POT.+\"(1540) e \"\'ksi\' POT.--\" (1862), a largura de decaimento da \"\'teta\' POT.+\" e a constante de acoplamento e fator de forma presentes no vertice J/ \'psi\' \"DD POT.*\". No estudo dos pentaquarks, usamos dois tipos de campos interpolantes contendo dois diquarks altamente correlacionados. Obtemos as massas consistentes com os dados experimentais, porém esta regra de soma têm uma grande contribuição do contínuo e a OPE não é muito boa. Obtivemos uma largura de decaimento compatível com os valores experimentais desde que sejam subtraídos diagramas que representam a \" \'teta\' POT.+\" como um estado ligado K - n. No estudo do vértice vertice J/ \'psi\' \"DD POT.*\" calculamos o fator de forma e a constante de acoplamento, considerando três casos: D off-shell, \"D POT.*\" off-shell e J/ \'psi\' off-shell. A constante de acoplamento é a mesma nesses três casos, porém o fator de forma depende da escolha da partícula off-shell, onde para a J/ \'psi\' off-shell o fator de forma é bem mais duro que o fator de forma obtido para os outros casos. Também comparamos os nossos resultados com outros métodos: o modelo de quark méson constituintes e o modelo de quarks relativísticos constituintes / We use the QCD sum rules to obtain the masses of the pentaquarks _+(1540) and _−−(1862), _+ decay width and the coupling constant and the form factor for the J/ DD* vertex.In the study of the pentaquarks, we use two kinds of interpolating fields, containing two highly correlated diquarks. We get the masses in a good agreement with the experimental value, but this sum rule has a large continuuum contribution and the OPE convergence is not so good. We get the decay width compatible with the experimental value, since we subtract the diagrams that represent _+ as a K − n bound state. In the study of J/ DD* vertex, we calculate the form factor and the coupling constant considering three cases: D off-shell, D* off-shell and J/ off-shell. The coupling constant is the same in those three cases, however the form factor depends on the choice of the particle off-shell, where for the J/ off-shell the form factor is much harder than the form factor obtained for the other cases. We also compare our results with other methods: the constituent quark meson model and the relativistic constituent quark model.
182

Cardosin A Molecular Determinants and Biosynthetic Pathways / Déterminants moléculaires et voies de synthèse de la cardosine A

Pereira, Cláudia 29 October 2012 (has links)
La cardosine A est une protéase aspartique identifiée il y a plus de 20 ans dans les cellules du chardon Cynara cardunculus. Sa distribution dans tous les tissus de la plante et ses caractéristiques enzymatiques ont été caractérisées par approches biochimiques. La cardosine A a des fonctions essentielles dans la reproduction, la mobilisation de réserves protéiques, et le remaniement de membranes. Pour assumer ces différentes fonctions, la cardosine A doit pouvoir transiter et s’accumuler dans différents compartiments intracellulaires : vacuole de stockage, vacuoles lytiques, ou autres compartiments membranaires. Il n’y a cependant que très peu de données disponibles sur les mécanismes de biosynthèse, de tri, de transport et d’adressage aux différents compartiments cellulaires. De récents travaux suggèrent que l’expression en modèle hétérologue pourrait être utilisée pour une meilleure compréhension de la biologie intracellulaire de la cardosine A. Les résultats de cette étude montrent que l’expression transitoire de la cardosine A dans les feuilles de Nicotiana tabacum est un bon modèle expérimental pour explorer le transport de la cardosine A dans la cellule. En effet dans ce système les mécanismes de maturation et de transport de la protéine à la vacuole sont conservés. De plus, une lignée stable d’Arabidopsis thaliana exprimant la cardosine A sous promoteur inductible s’est également avérée un bon modèle d’étude du transport intracellulaire de la cardosine A. L’utilisation de ces systèmes hétérologues a permis de combiner l’expression de formes mutées de la cardosine A (dans lesquelles des séquences spécifiques ou des acides aminés avaient été tronqués ou modifiés) avec des approches de biochimie et d’imagerie cellulaire pour identifier des signatures moléculaires responsables de l’adressage vacuolaire de la protéine. Nos résultats montrent que la cardosine A a deux déterminants vacuolaires dans sa séquence protéique : le domaine “PSI”, qui définit un déterminant d’adressage vacuolaire original et propre à certaines protéases aspartiques, et un peptide C-terminal appartenant à la classe bien définie des ctVSD. De plus, les résultats montrent que la présence de ces deux déterminants illustre la capacité d’emprunter deux routes distinctes pour atteindre la vacuole : le domaine PSI peut permettre d’attendre la vacuole sans passer par le Golgi, tandis que le domaine C-ter négocie un transport classique Reticulum, Golgi, Prévacuole, Vacuole. Cette capacité à choisir deux routes différentes n’est pas observée pour la cardosine B, autre protéase aspartique du chardon présentant une haute homologie de séquence avec la cardosine A. Pour expliquer cette capacité de la cardosine A à emprunter deux routes vacuolaires différentes, l’hypothèse d’un rôle possible de la glycosylation dans le tri des protéines entre les deux routes vacuolaires est alors étudiée. L’expression de la cardosine A dans les graines en germination d’Arabidopsis thaliana révèle que la protéine peut s’accumuler d’une manière différentielle dans les graines en absence de germination ou pendant la germination, tout au long du système endomembranaire jusqu’à la vacuole de réserve ou dans les vacuoles lytiques en formation. Les expériences de blocage de transport du Reticulum au Golgi n’ont pas permis de conclure d’une manière certaine si les accumulations vacuolaires dérivaient d’un transport pouvant court-circuiter le Golgi comme dans les feuilles de Nicotiana. Au total, la cardosine A constitue une protéine modèle pour étudier les transports vacuolaires chez Nicotiana tabacum and Arabidopsis thaliana, deux systèmes hétérologues qui permettent de développer des méthodes complémentaires pour une exploration fonctionnelle des mécanismes impliqués. Cette étude permet de contribuer à une meilleure connaissance de la biologie des cardosines en particulier, et des protéases aspartiques en général. / The aspartic proteinase cardosin A is a vacuolar enzyme found to accumulate in protein storage vacuoles and lytic vacuoles in the flowers and in protein bodies in seeds of the native plant cardoon. Cardosin A has been first isolated almost two decades ago and has been extensively characterized since, both in terms of distribution within the tissues and of enzyme biochemistry. In the native system, several roles have been addressed to cardosin A in reproduction, mobilization of reserves and membrane remodeling. To participate in such diverse events, cardosin A must accumulate and travel to different compartments inside the cell: protein storage vacuoles, lytic vacuoles, cytoplasmic membrane (and eventually outside the cell). However, not much information is available regarding cardosin A biogenesis, sorting or trafficking to the different compartments. Recent studies have approached the expression of cardosin A in Arabidopsis thaliana and Nicotiana tabacum. These preliminary observations were the starting point of a detailed study of cardosin A expression, localisation, sorting and trafficking routes, resourcing to several and very different methods. It has been showed that transient expression of cardosin A in Nicotiana tabacum leaf is a good system to explore cardosin A trafficking inside the cell, as the protein is processed in a similar manner as the control and accumulates in the vacuole. Furthermore, an Arabidopsis thaliana line expressing cardosin A under an inducible promoter was explored to understand cardosin A dynamics in terms of vacuolar accumulation during seed germination events. Similarly to the Nicotiana tabacum one, this system was also validated for cardosin A expression and it allowed to conclude that the protein’s expression did not retrieved any phenotype to the cells or individuals. However, experiments conducted in BY-2 cells revealed to be inconclusive since cardosin A expression in this system is not predictable. The data obtained along this work using several cardosin A mutated forms, lacking specific domains or point-mutated, allowed to determine that cardosin A has two Vacuolar Sorting Determinants in its protein sequence: the PSI, an unconventional sorting determinant, and the C-terminal peptide, a C-terminus sorting determinant by definition. Furthermore, it was also demonstrated that each domain represents a different route to the vacuole: the PSI bypasses the Golgi Apparatus and the C-terminal peptide follows a classic Endoplasmic Reticulum-Golgi Apparatus-Prevacuole route to the vacuole. This difference in the trafficking routes is not observed for cardosin B sorting determinants as both the PSI and C-terminal peptide from cardosin B needs to pass the Golgi Apparatus to reach the vacuole. A putative role for glycosylation in the trafficking routes is further discussed as cardosin A PSI, contrary to cardosin B, is not glycosylated. The production of mutants affecting cardosin A glycosylation sites supported this idea. Moreover, cardosin A expression in germinating Arabidopsis thaliana seeds revealed a differential accumulation in non-germinated and germinated seedlings. Cardosin A was detected along the secretory pathway to the Protein Storage Vacuole in association with the Endoplasmic Reticulum, Golgi Apparatus, Prevacuole and newly formed Lytic Vacuoles. The drug Brefeldin A caused the protein to be retained in the Golgi Apparatus, despite some amount being still detected in the vacuole, not being clear if the Golgi Apparatus bypass observed in Nicotiana tabacum leaves occurs in this system. As a whole, cardosin A confirmed to be a good model to study vacuolar sorting in these two systems that complement each other in terms of approaches available. This study provided good results in order to understand in more detail cardosin A biology in particular and vacuolar trafficking of plant Aspartic Proteinases as a group.
183

Signální psi a jejich využití u osob s diabetes mellitus / Signal alert dogs and their use in people with diabetes mellitus

Zemanova, Monika January 2019 (has links)
The theses is focused on diabetic alert dogs, which create impact on compensation of diabetes mellitus. Differences in topic's between Czech republic and USA is compared based on questionnaire. Part of diploma thesis is also short questionnaire dedicated for members of Czech republic parliament. The aim of thesis is to extend public knowledge about diabetic alert dogs in Czech republic. To compare knowledges about this topic between Czech republic and USA and to compare number of owners of diabetic alert dogs in Czech republic and USA. Analysis was done by using selected method of questionnaire targeting this topic. Questions were related to people suffering from diabetes mellitus in Czech republic and USA. Second anonymous questionnaire was prepare for members of Czech parliament and their knowledges about this topic. Structualized interwievs with people suffering from diabetes were conducted only for additional information. Key words signal alert dogs, diabetes mellitus, assistance dogs, assistive device
184

Försök till att lösa degraderingsproblem vid preparation av fotosystem I-subenheten PSI-N genom att använda proteasinhibitorer och olika sorters lysis / Trying to solve degradation problem when preparing PSI-N from the photosystem I complex using protease inhibitors and different kinds of lysis

Jedenheim, Linda, Eriksson, Johanna January 2010 (has links)
<p>Fotosyntesen kallas den process som omvandlar ljusenergi till kemisk energi. Fotosyntesen sker i tylakoidmembranet och drivs av två stora proteinkomplex, fotosystem II (PSII) och fotosystem I (PSI) då de tillförs energi i form av fotoner. PSI-N är ett mindre protein på ca 10 kDa som ingår i PSI. På något sätt, som ännu inte är klarlagt, samverkar PSI-N med PSI-F och plastocyanin när det dockar till PSI. Det är därför av viktigt att rena fram större mängder av PSI-N för att få djupare kunskaper om proteinet samt dess struktur och funktioner. Tidigare undersökningar har utförts i ämnet och ett fusionsprotein innehållande PSI-N har uttryckts i <em>Escherichia coli</em> (<em>E.coli</em>). Problem har dock uppstått efter lysis av cellerna då det har visat sig att fusionsproteinet har degraderats. Vårt examensarbete strävar efter att rena fram intakt fusionsprotein med hjälp av, framför allt, mekanisk lysis och proteasinhibitorer.</p> / <p>The process where light is converted into chemical energy is called photosyntesis. The reaction takes place in the thylakoid membrane and is driven by two major protein complexes, photosystem II (PSII) and photosystem I (PSI) when energy in form of photons are received. PSI-N, a subunit in PSI, is a smaller protein with a mass of approximately 10 kDa. In some way, which is not yet clarified, PSI-N collaborates with PSI-F and plastocyanin when plastocyanin is docking to PSI. It is therefore important to purify larger amounts of the protein to acquire deeper knowledge of its structure and function. In earlier research the PSI-N protein has been expressed in <em>Escherichia coli</em> (<em>E.coli</em>). The problem has been degradation of the fusion protein after lysis. Our goal with this project is to obtain the purified protein intact using mechanic lysis and protease inhibitors.</p>
185

STRESS, RELAZIONI e LAVORO: due studi sugli operatori dei dipartimenti di emergenza e accettazione

PINI, ERIKA 20 February 2009 (has links)
No description available.
186

Försök till att lösa degraderingsproblem vid preparation av fotosystem I-subenheten PSI-N genom att använda proteasinhibitorer och olika sorters lysis / Trying to solve degradation problem when preparing PSI-N from the photosystem I complex using protease inhibitors and different kinds of lysis

Jedenheim, Linda, Eriksson, Johanna January 2010 (has links)
Fotosyntesen kallas den process som omvandlar ljusenergi till kemisk energi. Fotosyntesen sker i tylakoidmembranet och drivs av två stora proteinkomplex, fotosystem II (PSII) och fotosystem I (PSI) då de tillförs energi i form av fotoner. PSI-N är ett mindre protein på ca 10 kDa som ingår i PSI. På något sätt, som ännu inte är klarlagt, samverkar PSI-N med PSI-F och plastocyanin när det dockar till PSI. Det är därför av viktigt att rena fram större mängder av PSI-N för att få djupare kunskaper om proteinet samt dess struktur och funktioner. Tidigare undersökningar har utförts i ämnet och ett fusionsprotein innehållande PSI-N har uttryckts i Escherichia coli (E.coli). Problem har dock uppstått efter lysis av cellerna då det har visat sig att fusionsproteinet har degraderats. Vårt examensarbete strävar efter att rena fram intakt fusionsprotein med hjälp av, framför allt, mekanisk lysis och proteasinhibitorer. / The process where light is converted into chemical energy is called photosyntesis. The reaction takes place in the thylakoid membrane and is driven by two major protein complexes, photosystem II (PSII) and photosystem I (PSI) when energy in form of photons are received. PSI-N, a subunit in PSI, is a smaller protein with a mass of approximately 10 kDa. In some way, which is not yet clarified, PSI-N collaborates with PSI-F and plastocyanin when plastocyanin is docking to PSI. It is therefore important to purify larger amounts of the protein to acquire deeper knowledge of its structure and function. In earlier research the PSI-N protein has been expressed in Escherichia coli (E.coli). The problem has been degradation of the fusion protein after lysis. Our goal with this project is to obtain the purified protein intact using mechanic lysis and protease inhibitors.
187

Ondes internes, de l'instabilité au mélange. Approche expérimentale / Internal Waves. From instability to mixing. Experimental study

Bourget, Baptiste 01 July 2014 (has links)
Les ondes internes de gravité jouent un rôle important dans les échanges énergétiques océaniques, en particulier par leur mécanisme d'atténuation. Il est alors crucial de déterminer et de quantifier les différents processus permettant un transfert d'énergie vers les petites échelles et aboutissant ainsi au mélange océanique. Nous avons, pour cela, étudié précisément l'un de ces mécanismes: l'Instabilité Paramétrique Sous-harmonique (PSI). Cette instabilité permet la génération de deux ondes internes, de fréquence et de vecteurs d'ondes différents, à partir d'une onde primaire, par interaction non-linéaire résonante. L'étude expérimentale de cette instabilité a ainsi permis de mettre en évidence l'importance de certains paramètres (fréquence, amplitude, largeur de faisceau) quant au développement et à la sélection des ondes secondaires. Ces paramètres influent donc sur le transfert énergétique entre les échelles. En outre notre dispositif expérimental a permis de tester les limites de la théorie développée jusqu'à présent et a conduit à l'élaboration d'un nouveau modèle validé expérimentalement et numériquement.Par ailleurs, nous avons adapté la technique de Fluorescence Induite par Laser (LIF) à des fluides continûment stratifiés afin d'effectuer des mesures simultanées de vitesse (PIV) et de densité (LIF). Cette technique permet ainsi d'étudier expérimentalement l'effet de la propagation et de la déstabilisation des ondes internes de gravité sur une stratification linéaire, et d'accéder à des grandeurs associées au mélange. / Internal waves are believed to be of primary importance as they affect energy transfer, especially their dissipation mechanism. Therefore it is crucial to identify and measure the different processes evolving a transfer to smaller scales and leading to oceanic mixing. We have chosen to focus on one of these mechanisms: the Parametric Subharmonic Instability (PSI). This instability allows the generation from a primary wave of two secondary internal waves, with different frequencies and waves vectors, by nonlinear resonant interaction. The experimental study of this instability has helped to highlight the importance of some parameters (frequency, amplitude, beam width) for the development and the selection of secondary waves. Thus these parameters affect the energy transfer between scales. Moreover, our experimental device was used to test the limits of the theory developed so far and has led to the development of a new model, which has been validated experimentally and numerically.In addition, we adapted the technique of Laser Induced Fluorescence (LIF) to continuously stratified fluids, with the aim of performing simultaneous measurements of velocity (PIV) and density (LIF). This technique allows us to study experimentally the effect of propagation and destabilization of internal gravity waves on a linear stratification, and to access to quantities related to the mixing.
188

Mechanické vlastnosti plastů / Mechanical Properties of Plastics

Pavlíková, Petra January 2008 (has links)
Diploma paper deals with fracture toughtness of pipe type HDPE. The influence of material structure on its fracture toughness at temperature 0°C and 23°C measured by PSI test was determined. Experimental results were compared with gained results of S4 test and the conclusions about usage of PSI test in screening of impact properties of polymeric materials were formulated.
189

Investigating Communication and Social Behaviour Using Wearable Sensor Technology

Finnerty, Ailbhe N. January 2015 (has links)
The behaviour that we exhibit contributes to the message that is communicated to those that we are interacting with and can have an impact on how the message is conveyed and interpreted. Nonverbal behaviour is just as important to be aware of as well as what is being said, as the subtleties of behaviour can impact the outcome of interactions. Advancements in research technologies have allowed us the chance to investigate natural human behaviour is a variety of settings outside of the laboratory, however, some gaps in the understanding of behaviour exist. The aim of this thesis is to investigate communication and social interactions in a variety of settings, paying particular attention to the methods of data collection, specifically the use of wearable sensors, to investigate phenomenon from social psychology. The thesis aims to address three specific research questions; 1) if can we predict stress using a combination of nonverbal behavioural cues along with physiological measurements, 2) understand the factors affecting happiness and productivity in the workplace from features of communication taken from wearable sensors and 3) determine the stressors that can be characterised from communication patterns assessed through Call Detail Records and smartphone sensors. The studies presented here focus on the nonverbal aspects of communication that can be measured through wearable and sensing devices. In the three types of scenarios that are detailed in the different chapters, the interactions considered are face to face meetings in a one on one interaction, co-location within a defined space in an organisation and the communications of a widely dispersed community. The interactions are recorded by wearable devices such as the Affectiva Q sensor, the Sociometric Badge, and smartphones equipped with sensing capabilities in the form of the funf and P-OWL platforms for data recording, among other forms of data collection. Each of the studies included aspects of self reported assessments that were used as a ground truth measurement of affect: these were annotations of stress, self reports of fear of negative evaluation, self perception, positive and negative affect and stress, among others. The goal was to examine how to use digital traces of behavioural expressions to have a greater understanding of these interactions and how the way in which we interact with others has an impact on the individual. The work from this thesis adds to the existing literature on these various issues by addressing the research questions from a novel perspective. The studies found support for each of the research questions and by using a mixed methods approach and digital traces from wearable sensors gained insights into how communication impacted the individual, revealing the important aspects of communication and their effect on stress, productivity and well-being.
190

Neural mechanisms underlying socioemotional behavior in typical and atypical populations

Ciringione, Luciana 06 December 2021 (has links)
This doctoral thesis outlines the review and experimental studies conducted during my Ph.D. that aimed to clarify the neurocognitive processes underlying socioemotional behavior in neurotypical and Autism Spectrum Disorders (ASD) individuals, a clinical population with impairments in the socioemotional core. The thesis is divided into four chapters. Chapter 1 is concerning the involvement of the hypothalamus in socioemotional behavior. Indeed, despite the large number of studies on the relationship between hypothalamic neuropeptides and social behavior in ASD, only a few studies investigated the association between the hypothalamus and socioemotional response in ASD. Results from this review highlighted anatomical hypothalamic atrophy and functional hypothalamic hypoactivation during face processing and social interaction tasks. The above results from the review highlighted the need to have an appropriate paradigm to investigate hypothalamic involvement in socioemotional behavior. For this reason, in Chapter 2, I performed a systematic review of the neuroimaging studies that used a classical conditioning paradigm to study socioemotional behavior. Results raised the presence of a gap in the literature: indeed, it has been shown that (1) no study used a purely social unconditioned stimulus; (2) the literature mainly focused on conditioning to aversive stimuli, whereas no study focused on conditioning to positive stimuli. Building on this evidence, an EEG study, described in Chapter 3, aimed to investigate whether classical conditioning also underlies the acquisition of socioemotional preference using a novel conditioning paradigm employing more ecological positive and neutral social stimuli. Results show that even with a short period of classical conditioning an increase in valence and attractiveness of positive conditioned stimuli, which was previously neutral may be performed. Then, explorative analysis of the event-related potentials (i.e., the Late Positive Potential, LPP) highlights differences about the LPP elicited by the positive conditioned stimuli concerning neutral conditioned stimuli. Finally, as a side project, Chapter 4 illustrates an investigation that aimed to explore differences in sleep between ASD and neurotypical populations and describe their relationship with the impaired socioemotional characteristics.

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