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1
De, Marco Margot. « BAG3 role in cardiomyocytes physiopathology ». Doctoral thesis, Universita degli studi di Salerno, 2013. http://hdl.handle.net/10556/896.
Texte intégralRésumé :
2010 - 2011The anti-apoptotic protein BAG3 is expressed at high levels in skeletal and cardiac muscle in vivo. Our group recently focused its interest on BAG3 role in myocardiocyte proliferation, survival and response to stressful stimuli. We found that BAG3 is upregulated during the differentiation of cardiomyoblasts. Our results prompted us to verify whether bag3 silencing could affect the differentiation state of cardiocytes and we found that bag3 silencing resulted in highly reducing the levels of myogenin. Furthermore, we analyzed BAG3 expression and localization following cell exposure to oxidative stress. In particular, we found that epinephrine in vitro increases BAG3 expression in adult human cardiomyocytes. We evaluated whether BAG3 could be involved in the Tako-tsubo cardiomyopathy (or stress cardiomyopathy) pathogenesis that is characterized by left ventricular dysfunction, with symptoms that can mimic an acute coronary syndrome. The absence of significant cardiovascular risk factors in patients affected by stress cardiomyopathy suggested that it might be associated with a possible genetic etiology. Therefore, we sequenced bag3 gene to check for polymorphisms in 29 patients and 1043 healthy donors. Three polymorphism were highly represented among patients (R71Q, C151R, P407L). We also showed for the first time that BAG3 protein is released from stressed cardiomyocytes and is found in chronic heart failure (HF) patients’ sera. Since anti-BAG3 antibodies are also present in patients’ sera, we developed an ELISA test for their specific detection. In serum samples from chronic HF patients, we found significantly higher values of anti-BAG3 antibodies respect to samples from healthy donors. The presence of anti-BAG3 antibodies in chronic HF patients’ sera and the availability of an ELISA test for their detection can contribute a novel tool for diagnostic and prognostic evaluations. [edited by author]
X n.s.
2
Jameson, Iain. « The pion-nucleon sigma term and the SU(3) Cloudy Bag Model / ». Title page, contents and abstract only, 1991. http://web4.library.adelaide.edu.au/theses/09PH/09phj31.pdf.
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Séguin, Samuel. « Le chaperon HspB8 Bag 3 pour stimuler la dégradation des protéines à polyglutamine par macroautophagie ». Master's thesis, Université Laval, 2008. http://hdl.handle.net/20.500.11794/20167.
Texte intégralRésumé :
HSPB8 appartient à la famille des petites protéines de choc thermique (sHSP ou HSPB) qui contient 10 membres HSPB 1-10. In vitro, HspB8 favorise la dégradation de l'Huntingtine mutée (Htt43Q), une protéine encline à agréger. HspB8 est un chaperon moléculaire capable de reconnaître des substrats protéiques mal repliés pour permettre leur repliement ou leur dégradation. HspB8 forme un complexe stable et stoechiométrique avec Bag3 (2 : 1), un cochaperon de Hsp70. Surexprimées, Bag3 et/ou HspB8 induisent la conversion de LC3-I en LC3-II indiquant que la macroautophagie est stimulée et bloquent l'agrégation de Htt43Q. Nous avons cherché dans cette étude, à déterminer si la formation du complexe HspB8-Bag3 est essentielle dans l'accomplissement de ce phénomène. Bag3 possède un domaine WW peu caractérisé, un domaine riche en proline capable d'interagir avec PLCy l , et un domaine BAG interagissant avec Hsp70 et Bcl-2. Le co-chaperon Bag3 étant modulaire, nous avons recherché quels domaines d'interaction fonctionnels lui sont essentiels. Afin de localiser le site de liaison à HspB8, nous avons réalisé des délétions systématiques des différentes régions de Bag3. L'interaction des différents délétants de 6His-Bag3 avec HspB8 a été analysée par co-puri fi cation au Nickel. Leur capacité à bloquer l'accumulation de Htt43Q dans les fractions solubles et insolubles au SDS et à augmenter le ratio LC3-II/I, marqueur de l'autophagie, a été évaluée. Nous avons déterminé que le site de liaison à HspB8 était constitué de deux motifs répétés de 14 acides aminés très conservés (B8bdl et B8bd2) depuis le poisson jusqu'à l'Homme. Dans les HEK-293T, en l'absence d'interaction avec HspB8, Bag3 est toujours capable de stimuler la macroautophagie et la dégradation de Htt43Q, bien qu'aucune activité de chaperon moléculaire ne lui soit associée in vitro. L'analyse des autres délétants suggère que l'extrémité N-terminale ainsi que la région riche en proline seraient essentielles pour l'activité de Bag3 envers Htt43Q, bien qu'elles ne le seraient pas pour stimuler la macroautophagie. Le domaine C-terminal de Bag3 serait responsable de la stimulation de la macroautophagie et sa délétion bloquerait aussi la dégradation de Htt43Q. La protéine Bag3, en permettant la dégradation des protéines mal conformées (comme Htt43Q) par macroautophagie, jouerait un rôle prépondérant dans le contrôle de la qualité des protéines.
4
Rockvam, Margaux. « Caractérisation de microstructures de joints brasés avec les alliages BCu-1, BAg-13a, BAu-4, BAu-6, BNi-1a, BNi-2, BNi-3 et Palnicro 36M ayant pour métal de base un superalliage base nickel ». Mémoire, École de technologie supérieure, 2011. http://espace.etsmtl.ca/911/1/ROKVAM_Margaux.pdf.
Texte intégralRésumé :
Cette étude avait pour but de caractériser les microstructures de joints brasés ayant pour
métal de base de l’Inconel 625. Les brasures employées sont toutes utilisées en production
chez Pratt & Whitney Canada et sont au nombre de huit : BCu-1, BAg-13a, BAu-4, BAu-6,
Palnicro 36M, BNi-1a, BNi-2 et BNi-3. Une des contraintes importantes de cette étude a été
de rester le plus proche possible de ce qui se fait en production afin de mieux comprendre le
comportement des pièces de service par la suite.
Dans un premier temps, des essais de mouillage ont été réalisés dans le but de mieux
connaître les alliages de brasage étudiés, certains ayant un comportement totalement inconnu.
Les angles de mouillage et le diamètre d’étalement d’une goutte de brasure ont été relevés
pour différentes combinaisons des paramètres de four de brasage. Ceci a été fait pour toutes
les brasures. L’étude s’est poursuivie par une autre série d’essais destinés eux à l’observation
et à la compréhension de la microstructure des joints brasés. Pour cela, l’écartement entre les
deux plaquettes d’Inconel 625 variait entre 0 et 175 μm. De plus, deux temps de brasage ont
été choisis : 15 et 150 minutes, permettant ainsi de couvrir une vaste gamme de cas présents
dans le monde industriel. Pour caractériser ces microstructures, il a fallu identifier les phases
en présence, les quantifier et enfin essayer de les nommer et/ou de les catégoriser. Toutes les
analyses ont été faites grâce à des appareils sophistiqués comme le microscope électronique à
balayage à cathode chaude ou encore la microsonde atomique, dû à la présence de bore dans
certains alliages de brasage.
Les essais de mouillage ont permis de montrer que toutes les brasures possèdent un excellent
mouillage avec un écoulement contrôlable lors de brasage sous vide en atmosphère partielle.
Des valeurs de paramètres de four permettant d’optimiser le mouillage ont aussi été
déterminées. Les analyses de caractérisation et d’identification de la microstructure ont mis
en évidence une répartition du joint en différentes zones, souvent communes entres les
brasures. Les brasures d’une même famille possèdent une microstructure avec de nombreux
points communs d’un point de vue morphologique. Cependant, des spécificités sont propres à
chacune ce qui pourra faire une différence sur le comportement mécanique de la pièce. Les
brasures à base de nickel sont très complexes et forment des phases eutectiques binaires ou
ternaires au milieu de phases simples et de phases précipitées. Les alliages à base d’or
présentent une structure dite d’eutectique à très fines lamelles mais dont la répartition est
particulière. L’alliage BAg-13a est lui principalement constitué d’une phase eutectique en
« dentelle » et le BCu-1 montre simplement une solution solide de cuivre parsemée de petites
phases riches en chrome sur la ligne centrale du joint.
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SILVA, MAVIAEL J. da. « Desenvolvimento de selantes vitrocerâmicos para uso em SOFC pertencentes ao sistema BAS (BaO-Alsub(2)0sub(3)-SiOsub(2)) modificados com Bsub(2)Osub(3) ». reponame:Repositório Institucional do IPEN, 2014. http://repositorio.ipen.br:8080/xmlui/handle/123456789/23655.
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Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2015-04-10T16:38:07Z
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Tese (Doutorado em Tecnologia Nuclear)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Deles, Romain. « Quand on n'a "que" BAC + 3... : les étudiants et l'insertion professionnelle ». Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0163/document.
Texte intégralRésumé :
Cette thèse porte sur l'insertion professionnelle des étudiants. Ellesoulève en particulier deux questions : la question des possibilités objectivesd'insertion professionnelle pour les diplômés de l'enseignement supérieur, et apporteainsi une contribution au débat sur la dévalorisation des diplômes ; la question del'expérience de l'insertion professionnelle des jeunes dans le contexte institutionnelet social français marqué par la nécessité de s'établir professionnellement.Les figures de « l'intello précaire » ou de « l'ouvrier bachelier » incarnent lesdifficultés d'emploi d'une jeunesse qualifiée. Ce phénomène doit être relativisé : lesjeunes diplômés du supérieur ont des niveaux de chômage beaucoup plus faiblesque les non-diplômés. Les mesures habituelles de la rentabilité des diplômes sontrassurantes : une année d'études supérieures supplémentaire continue d'apporter unsurcroit de revenu de 8%. La dévalorisation des diplômes ne serait alors qu'un« mythe ». Ces constats optimistes reposent cependant sur des indicateurs trèsagrégés : les performances en termes d'insertion professionnelle sont appréciées enfonction du nombre d'années d'études ou du niveau de diplôme. On mesure parexemple les chances d'insertion professionnelle des bacheliers et des titulaires demaster et l'on compare les rentabilités relatives des diplômes. Les études sont donccomprises comme un ensemble homogène de savoirs : les parcours, les contextesd'enseignement, l'intensité du travail de chaque étudiant, et, surtout, la spécialité dediplôme poursuivie sont gommées dans la mesure traditionnelle de la rentabilité desdiplômes. Cette thèse, à partir d'une analyse secondaire de données quantitatives,cherche à préciser cette mesure en réintroduisant la spécialité de diplôme. Onobserve alors qu'à niveau de diplôme équivalent, il existe de fortes disparités entreles spécialités de formation dans la probabilité de s'insérer et dans la qualité desemplois occupés. La spécialité détermine autant que le niveau de formation l'accès àun emploi qualifié. Ainsi, ce travail conclut à l'existence d'effets d'inflation scolairelocaux, situés sur des spécialités de formation précisesThis thesis focuses on the transition to work of students. It raises especially twoquestions: the question of objective employability opportunities for graduates of higher education,and makes in this way a contribution to the debate on the devaluation of diplomas ; the questionof the experience of the professional integration of young people in the French institutional andsocial context marked by the need to establish professionally.Figures of "intello précaire" or "ouvrier bachelier" embody the employment difficulties ofskilled youth. This phenomenon must be relativized: young university graduates have much lowerlevels of unemployment than non-graduates. Standard measures of profitability diplomas shouldlead to optimism : an additional year of higher education continues to provide 8% additionalincome. The devaluation of diplomas seems to be a "myth." However, these optimisticconclusions are based on highly aggregated indicators : the performance in terms of professionalintegration are assessed according to the number of years of schooling or the level of education.One measures for example the chances of employability of baccalauréat graduates and of masterholders and compares the relative profitability of these diplomas. In this way, the studies areunderstood as a continuum of knowledge : educational contexts, work intensity of each student,and especially the field of education pursued are not considered in the traditional measure ofprofitability diplomas. This thesis, based on a secondary analysis of quantitative data, precisesthis traditional measure by reintroducing the field of education. One can notice that at the samelevel of degree, there are wide disparities between training specialties in the probability of findingskilled jobs. The field of education determines as much as the level of training access to a skilledjob. Thus, this work concludes at the existence of local overeducation effects, located on specifictraining specialties
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Parghi, Nirav. « Characterization of Insulin-like Growth Factor Binding Protein-3 (IGFBP-3) interaction with the Bovine Aortic Endothelial (BAE) cell surface : Examination of the Role of Heparan Sulfate Proteoglycans (HSPG) ». Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36928.
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Insulin-like growth factor binding proteins (IGFBPs) are known to be important modulators of the insulin-like growth factor (IGF-I). However, their precise role is as yet unclear. Further, recent studies have indicated that IGFBP-3 has a receptor mediated growth inhibitory response of its own. In the present study, we quantified the binding characteristics of IGFBP-3 to bovine aortic endothelial (BAE) cells. Binding studies at 4 oC were conducted and a specific binding curve for IGFBP-3 was obtained. IGFBP-3 was found to bind with an equilibrium dissociation constant (KD) value of 3.1 x 10-10 M. The role of heparan sulfate proteoglycans (HSPG) in the IGFBP-3 binding mechanism was also examined. It was seen that inactivation of the cell surface HSPGs with 75 mM sodium chlorate did not affect IGFBP-3 binding. Further, there have been reports of inhibition of IGFBP-3 binding by heparin in the media. Hence, the most probable interaction of HSPG with IGFBP-3 occurs in the extracellular region, with soluble HSPGs acting as receptors for IGFBP-3 and decreasing the net cell associated ligand receptor interaction. This is likely, since IGFBP-3 is known to possess a heparin binding domain. Simultaneous introduction of IGF-I and IGFBP-3 into the extracellular media decreased IGFBP-3 binding to the cell surface, which might imply that IGF-I and IGFBP-3 regulate each other's action.Master of Science
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Vallet, Isabelle. « Aerodynamique numerique 3-d instationnaire avec fermeture bas-reynolds au second ordre ». Paris 6, 1995. http://www.theses.fr/1995PA066225.
Texte intégralRésumé :
Cette these traite du developpement de methodes numeriques adequates pour les equations de navier-stokes 3-d compressibles avec fermeture au 2#n#d ordre bas-reynolds. Apres une breve revue des methodes d'aerodynamique numeriques et des modeles de turbulence associes, nous developpons une methode numerique resolvant les equations de navier-stokes ainsi que les equations de transport des quantites turbulentes. La discretisation spatiale est effectuee dans un maillage structure par une methode muscl decentree amont, utilisant une decomposition des flux de van leer, precise au 3#e#m#e ordre en espace. L'integration temporelle est implicite precise au 1#e#r ordre en temps et utilise une methode de factorisation approchee selon les directions du maillage. Pour des ecoulements stationnaires la convergence est acceleree en utilisant des pas de temps locaux avec cfl = 50. La methode est initialement appliquee a des ecoulements transsoniques stationnaires et instationnaires, avec fermeture k - #*. Des comparaisons systematiques avec les mesures sont effectuees. Des resultats tres satisfaisants sont obtenus en ecoulement instationnaire dans une tuyere de laval transsonique, ou la contre-pression aval fluctue. Ensuite un modele aux tensions de reynolds avec effets bas-reynolds et de proximite de paroi est developpe et implemente. Le modele est valide par comparaison avec l'experience de klebanoff sur plaque plane. Une comparaison de la methode avec des mesures detaillees dans une tuyere transsonique 3-d est effectuee. Les resultats sont satisfaisants, et les ameliorations possibles du modele de turbulence sont mises en evidence. La methode numerique developpee est particulierement robuste, pouvant converger a partir d'une initialisation automatique de l'ecoulement, developpee dans le cadre de cette these, grace a l'utilisation de limiteurs adequats de positivite et de noninfinite des quantites turbulentes
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Slepian, Zachary. « Revitalizing the 3-Point Correlation Function of Galaxies to Sharpen the BAO Standard Ruler ». Thesis, Harvard University, 2016. http://nrs.harvard.edu/urn-3:HUL.InstRepos:33493586.
Texte intégralRésumé :
Though dark energy constitutes 72% of the Universe’s present-day energy density, its nature remains unknown. Precise measurements of the Universe’s expansion over cosmic time constrain dark energy’s ratio of pressure to energy density and allow model discrimination. One of the leading techniques for measuring the expansion rate is the Baryon Acoustic Oscillation (BAO) method, which uses the imprint on galaxy clustering today of relativistic waves in the ionized early Universe as a standard ruler. Thus far, the BAO method has used correlations of pairs of galaxies (the 2-point correlation function or 2PCF) to make 1% precision cosmic distance measurements.
We present a derivation of the BAO’s late-time signature from first principles and then explore one of the few known possible sources of systematic error in the BAO method: a relative velocity between baryons and dark matter sourced by their different behaviors prior to redshift roughly 1000. We show how this systematic can shift the BAO scale measured from the 2PCF, and that it has a unique signature in correlations of galaxy triplets (the 3-point correlation function or 3PCF).
We then present a reformulation of the 3PCF with several transformative advantages: speed comparable to the 2PCF calculation, a tractable covariance matrix, and the ability to exploit all triangles. Using an algorithm this reformulation enables, we report the first high-significance (4.5σ) detection of the BAO in the 3PCF, allowing us to measure the distance to redshift 0.57 with 1.7% precision from the 3PCF alone. This distance scale measurement is highly independent of that from the 2PCF. Using it in conjunction with the 2PCF is equivalent to extending the observing time of the Baryon Oscillation Spectroscopic Survey (BOSS) by roughly 30%. We also make highly precise measurements of the linear biasing of galaxy formation and a moderate-significance (2.5σ) detection of tidal tensor biasing of galaxy formation. Finally, we place a 1% precision constraint on the baryon-dark matter relative velocity bias. This constraint means that the possible shift in the BAO scale measured from the BOSS 2PCF is less than a quarter percent and thus greatly sub-dominant to the statistical errors.Astronomy
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Breitenbach, Martin [Verfasser], Stefan [Gutachter] Ebbinghaus et Reinhard [Gutachter] Denecke. « Magnetoelektrische 3-3-Komposite durch Zonenschmelzen von Co1-xNixFe2O4/Ba1-xSrxTiO3-Eutektika : [kumulative Dissertation] / Martin Breitenbach ; Gutachter : Stefan Ebbinghaus, Reinhard Denecke ». Halle (Saale) : Universitäts- und Landesbibliothek Sachsen-Anhalt, 2020. http://d-nb.info/123224063X/34.
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Vagner, Marie. « Orientation des processus métaboliques du bar européen (Dicentrarchus labrax) par un conditionnement nutritionnel au stade larvaire ». Brest, 2008. http://www.theses.fr/2008BRES2009.
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Le but était de voir s’il est possible de stimuler les capacités de désaturation des acides gras pour la synthèse d’HUFA n-3 des juvéniles de bar par un conditionnement précoce. Lors d’une expérience 1 (F1), quatre groupes de larves ont reçu deux régimes de J6 à J45: LH (0,8% EPA+DHA) et HH (2,2%) à 16 ou 22°C. Après une période intermédiaire (2,7%, 19°C), la capacité des juvéniles à s’adapter à un régime carencé (0,5%) à été testée pendant 60 jours (19°C). L’expérience 2 (E2) avait pour but d’amplifier la réponse obtenue (une seul température d’élevage (19°C) et une gamme plus étendue de teneur en HUFA n-3 dans quatre régimes larvaires: XH (3,7%), HH (1,7%), LH (0,7%) et XLH (0,5%)). Après une période intermédiaire (2,7%, 19°C), les juvéniles ont reçu un régime à 0,35% pendant 35 jours. Les deux phases larvaires ont montré que les régimes carencés (0,8, 0,7 et 0,5%) stimulaient la transcription du gène de la delta-6 désaturase (∆6D, responsable de la première étape de synthèse des HUFA n-3) à J45. Mais une déficience en DHA dans les phospholipides (PL) et des retards de croissance ont été observés chez ces individus. Le conditionnement larvaire n’a pas affecté les performances de croissance des juvéniles mais E1 a montré une augmentation du niveau d’ARN de la (∆6D transitoire et une teneur en DHA des PL supérieure chez les juvéniles pré-conditionnés avec un régime carencé. F2 a mis en évidence une augmentation du niveau d’ARN tout au long de l’expérience mais une teneur en DHA similaire dans les PL. Il est possible de stimuler les capacités de désaturation des acides gras pour la synthèse d’HUFA n-3 des juvéniles de bar par un conditionnement précoceThe aim was to know if it is possible to apply a metabolic programming using nutritional conditioning during early larval stages to stimulate the fatty acid (FA) desaturation pathways of n-3 HUFA synthesis in marine fish. For the experience 1 (E1), four replicated groups of larvae were fed a diet with a Iow (LH) or high (HH) HUFA content from day 6 post-hatching to d-45 at 16 or 22°C: 0. 8 and 22% FPA÷DHA. After an intermediate period (19°C, 2. 7%), the capacity of juveniles to adapt to a HUFA-deprived diet (0. 5%) was tested during 60 days (19°C)- For the experience 2 (F2), four replicated groups of sea bass larvae were fed XH (3. 7% EPA+DHA), HH (1. 7%), LH (0. 7%) or XLH (0. 5%) diets from d-6 to d-45 at 19°C. After a period feeding a commercial diet (2. 7%, 19°C), the capacity of ail groups to adapt to an n-3 HUFA-Restricted diet (0. 3%) was tested for 35 days. The two larval periods indicated a positive modulation of the delta-6 desaturase (∆6D, rate-limiting enzyme responsible of the first step of the FA desaturation pathways for the n-3 HUFA synthesis) gene transcription by low dietary n-3 HUFA levels in larvae fed a low dietary HUFA n-3 content (0,8, 0,7 et 0. 5% EPA+DHA) than in others. Buta deficiency in DHA in phospholipides (PL) and a ower growth rate were observed, No significant effect of larval nutritional conditioning was observed in juveniles, but Fi showed a transient increase in mRNA level and an increase in DHA content in PL. F2 showed a persistent mRNA increase in pre-conditioned flsh, but similar DHA content in PL. T was possible to influence fatty acid desaturation pathways for HUFA synthesis, using a nutritional conditioning during larval stage
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Barrela, Ricardo Joel Martins Bernardino Marques. « Identificação e sequenciação de genes da via da lenhificação em bibliotecas BAC de Eucalyptus globulus ». Master's thesis, ISA/UTL, 2011. http://hdl.handle.net/10400.5/4188.
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Mestrado em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de AgronomiaIn this work we characterized two libraries containing BAC clones - EGC_Ba and EGC_Bb - obtained from fragments of genomic DNA of Eucalyptus globulus digested with HindIII and EcoRI respectively. The estimated genome coverage for the two libraries was 16X. Both libraries had inserts with average size of 115kb. Assessment of contamination by extranuclear genome was performed by hybridization of high-density colony filters, ensuring a low rate of contamination. The probability associated with the attempt to find specific sequences in the libraries was calculated at a value greater than 0.99. The identification of several genes involved in lignin biosynthetic pathway, transcription factors and peripheral regions of interest via PCR was performed using an innovative scheme of three-dimensional pools. Of the clones identified, thirteen were chosen for sequencing. The analysis of the sequences obtained allowed identifying the reduced presence of repetitive elements and microsatellites. The identified clones can be used in future researches involving the isolation of genes of QTL and genomic sequence comparison with other species of Eucalyptus.
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Schwemer, Thomas. « Ziel erreicht ? Untersuchung zur beruflichen Integration ehemaliger Schülerinnen und Schüler des Sonderschulheims Bad Sonder in Teufen ». Bern Ed. Soziothek, 2004. http://www.soziothek.ch/?3-03796-105-8.
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Barclay, Lauren Anne. « Direct Inhibition of the Conformational Activation of Pro-Apoptotic BAX by the BH4 Domain Helix of BCL-2 ». Thesis, Harvard University, 2014. http://nrs.harvard.edu/urn-3:HUL.InstRepos:13070041.
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Programmed cell death by apoptosis is required for normal development and tissue homeostasis. Perturbations of the critical signaling pathways that regulate apoptosis drive a number of pathologic diseases; therefore, a deep understanding of the apoptotic regulatory networks and methods for therapeutically modulating them is highly warranted. As constituents of the intrinsic pathway of apoptosis, pro-apoptotic BCL-2 family proteins respond to internal signals of cell stress to activate cell death through permeabilization of the outer mitochondrial membrane to release cytochrome c and other apoptogenic factors. Anti-apoptotic BCL-2 proteins block apoptosis by forming stable heterodimers with pro-apoptotic BAX and BAK. Specifically, the C-terminal binding groove of BCL-2 sequesters the BCL-2 homology 3 (BH3) death domain of BAX to prevent BAX oligomerization. The N-terminal BH4 domain of BCL-2 is also believed to confer anti-apoptotic activity but the mechanism by which this occurs remains unknown. A direct, inhibitory interaction between the BCL-2 BH4 domain and BAX was established through application of a peptide stapling technology to preserve the α-helical character of the BH4 domain outside the context of full-length BCL-2. Photoaffinity labeling identified a new mode of BH4 domain interaction at the C-terminal face of BAX, revealing an additional layer of apoptotic regulation. Examination of the conformational activation of full-length BAX in a lipid membrane by hydrogen-deuterium exchange mass spectrometry revealed that the BCL-2 BH4 helix blocks the BAX conformational changes triggered by an activating BH3 peptide to preserve the inactive BAX fold. Thus, the mechanistic paradigm for BCL-2 inhibition of BAX has been expanded to allow future opportunities for modulation of apoptosis by mimicking or inhibiting the BH4 motif.
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TSANGA, GUY. « Aerodynamique numerique 3-d des turbomachines axiales multi-etages avec fermeture k-epsilon bas-reynolds ». Paris 6, 1997. http://www.theses.fr/1997PA066181.
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L'aerodynamique numerique 3-d a atteint un degre de maturite qui doit permettre la prediction d'ecoulements aussi complexes que ceux qui se produident dans les turbomachines. Dans le cadre de cette these, une methodologie de resolution de l'ecoulement compressible, turbulent et stationnaire dans un environnement multi-rangees est developpee. Dans un premier temps, un programme de generation de maillages dans les turbomachines axiales est mis au point. Il consiste a creer des structures 3-d mono-bloc relatives a chaque rangee d'aubes, par empilement de coupes 2-d a topologie en o generees biharmoniquement. Deux domaines a topologie en h completent le champ de calcul pour l'entree et la sortie de la turbomachine. Dans un second temps, les differents maillages sont utilises pour la resolution iterative d'avancement en temps des equations de navier-stokes, moyennees par la procedure de favre et completees par la fermeture k-epsilon de launder-sharma. A l'aide d'une formulation aux volumes finis, la discretisation spatiale est effectuee avec la decomposition des flux de van leer et du schema decentre muscl. L'integration temporelle est implicite et factorisee adi. Les conditions aux limites sont traitees implicitement et explicitement a l'aide de mailles fantomes ajoutees aux differents domaines de la turbomachine. La methode numerique est validee par la comparaison avec des mesures experimentales et des resultats issus de codes internationaux, pour l'ecoulement transsonique dans le rotor nasa-37 avec un nombre cfl egal a 20. Une premiere etude multi-rangees est presentee pour un compresseur aeronautique. Les travaux effectues dans le cadre de cette these etablissent les bases du code de calcul turbo-3d. Ce dernier est robuste. Il repose sur une initialisation simple de l'ecoulement, grace a l'utilisation de limiteurs efficaces pour les variables turbulentes.
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Kibalama, Dennis Ssebina. « Design and Implementation of a Belted Alternator Starter System for the OSU EcoCAR 3 Vehicle ». The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1499247562822345.
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Lemesle, Martin Martine. « Neuropathie, angéite nécrosante et lymphome de bas grade avec dysglobulinémie monoclonale : à propos de 3 cas ». Dijon, 1994. http://www.theses.fr/1994DIJOM090.
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河島, 俊一郎. « Ba(Zn[1/3]Ta[2/3])O[3]-Ba(Zn[1/3]Nb[2/3])O[3]系, 及びBaO-Sm[2]O[3]TiO[2]系セラミックスの製造法とマイクロ波周波数帯における誘電特性に関する研究 ». 京都大学, 1990. http://hdl.handle.net/2433/162238.
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Dufour, Cécilie. « Contrôle de l'apoptose des ostéoblastes : implication de la PI3K in vitro et in vivo ». Paris 7, 2007. http://www.theses.fr/2007PA077232.
Texte intégralRésumé :
L'apoptose des cellules osseuses joue un rôle important dans la régulation de l'ostéogénèse. Cependant un dérèglement de l'apoptose contribue à différentes pathologies osseuses. L'objectif de notre travail est de caractériser le rôle de la voie PI3K/Akt dans l'apoptose des ostéoblastes en utilisant un modèle d'ostéoblastes mutés sur le FGFR-2 et un modèle d'hypokinésie chez le rat. Dans un premier travail, nous montrons que l'activation constitutive du FGFR-2 entraîne l'apoptose des cellules ostéoblastiques et que ceci est dû en partie par la dégradation de la PI3K par le protéasome. Nous avons établi un lien entre l'ubiquitine ligase c-Cbl et la PI3K, mettant à jour un des systèmes de régulation de celle-ci. Nous confirmons que la voie de survie PI3K/Akt est la voie principalement impliquée dans la survie des ostéoblastes et qu'elle est également un régulateur de l'apoptose dans ces cellules. Enfin, nous localisons cet événement dans les domaines particuliers de la membrane plasmique que sont les microdomaines lipidiques ou rafts. Dans un second travail, nous montrons que l'apoptose des ostéoblastes induite par réduction des contraintes mécaniques chez le rat est médiée par les intégrines a5(31 et que la voie de survie PI3K se trouve atténuée lors de la perte d'adhésion de ces intégrines à leur substrat. Nous montrons aussi que la voie de survie PI3K protège de l'apoptose en maintenant les taux de protéines anti-apoptotiques Bcl-2. La PI3K, molécule interagissant avec la signalisation FGF/FGFR et avec les intégrines, apparaît comme une molécule clé de la signalisation de survie des ostéoblastesBone cells apoptosis plays an important role in osteoblastogenesis regulation. When apoptosis is disturb, this leads to several bone pathologies. The aims of the study is to identify a role for PI3K signaling first in cell apoptosis induced by FGFR2 activation in human osteoblast and then in skeletal unloading induced by tail suspension in rats. First, we show that FGFR2 activation leads to decrease PI3K protein levels, resulting in attenuation of PI3K and Akt signaling in osteoblasts due to increased Cbl-PI3K molecular interaction. This results in increased PI3K ubiquitination and proteasome degradation. FGFR2 activation increases FGFR2-Cbl interact in raft micro-domains. These results reveal a novel role for PI3K/Akt attenuation in the control of osteoblast survival by FGFR2 signaling. Then, we show that skeletal unloading induces rapid osteoblast apoptosis which is associated with downregulation of a5(31 integrin expression and subséquent alteration of PI3K-Bcl-2 survival pathway in rat bone. PI3K, which interact with FGF/FGFR signaling and with integrins, appears to be a key molecule implies in osteoblast survival
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Nguyen, Tam Minh. « Drinking and driving in Vietnam : perceptions and risk ». Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/46083/3/Tam_Minh_Nguyen_Thesis.pdf.
Texte intégralRésumé :
Road traffic injuries are a major global public health problem but continue to receive inadequate attention. Alcohol influences both risk and consequence of road traffic injury but the scale of the problem is not well understood in many countries. In Vietnam, economic development has brought a substantial increase in the number of registered motorcycles as well as alcohol consumption. Traffic injury is among the leading causes of death in Vietnam but there is little local information regarding alcohol related traffic injuries. The primary goal of this study is to explore the drinking and driving patterns of males and their perceptions towards drink-driving and to determine the relationship between alcohol consumption and road traffic injuries. Furthermore, this thesis aims to present the situation analysis for choosing priority actions to reduce drinking and driving in Vietnam. The study is a combination of two cross-sectional surveys and a pilot study. The pilot study, involving 224 traffic injured patients, was conducted to test the tools and the feasibility of approach methods. In the first survey, male patrons (n=464) were randomly selected at seven restaurants. Face-to-face interviews were conducted when patrons just arrived and breath tests were collected when they were about to leave the restaurant. In the second survey, male patients admitted to hospital following a traffic injury (n=480, of which 414 were motorcycle or bicycle riders) were interviewed and their blood alcohol concentration (BAC) measured by breathalyzer. The results show broadly similar patterns of drinking and driving among male patrons and male traffic injured patients with a high frequency of drinking and drink-driving reported among the majority of the two groups. A high proportion of male patrons were leaving restaurants with a BAC over the legal limit. Factors that significantly associate with the number of drinks and BAC were age, hazardous drinking, frequency of drink-driving in the past year, self-estimated number of drinks consumed to drive legally, perceived family’s disapproval of drink-driving, and perceived legal risk and physical risk. The proportion of patrons and patients with BAC above the legal limit of 0.05 were 86.7% and 60.4% respectively, which was much higher than found in previous studies. In addition, both groups had a high prevalence of BAC over 0.15g/100ml (39.7% of patrons and 45.6% patients), a level that can seriously affect driving capacity. Results from the case-crossover analysis for patients indicate a dose-response relationship between alcohol consumption and the risk of traffic injury. The risk of traffic injury increased when alcohol was consumed before driving and there was a more than 13 fold increase when six or more drinks were consumed. Regarding perceptions towards drinking and driving, findings corroborate the low awareness among males in Vietnam, with a majority of respondents holding a low knowledge of safe and legally permissible alcohol use, and a low perceived risk of drinking and driving. The results also indicate a huge gap in prevention skills in terms of planning ahead or using alternative transport to avoid drink-driving and a perception by patrons and patients of a low rate of disapproval of drink-driving from peers and family. Findings in this study have considerable implications for national policy, injury prevention, clinical practice, reporting systems, and for further research. The low rate of compliance with existing laws and a generally low perceived legal risk toward drink-driving in this study call for the strengthening of enforcement along with mass media campaigns and news coverage in order to decrease the widespread perception of impunity and thereby, to reduce the level of drink-driving. In addition, no significant difference was found in this study on risk of traffic injuries between car drivers and motorcycle drivers. The current inconsistency between legal BAC for drivers of motorcycles, compared to cars, thus needs addressing. Furthermore, as drinking was found to be very common, rather than solely targeting drink-driving, it is important to call for a more strategic and comprehensive approach to alcohol policy in Viet Nam. This study also has considerable implications for clinical practice in terms of screening and brief interventions. Our study suggests that the short form of the AUDIT (AUDIT-C) screening tool is appropriate for use in busy emergency departments. The high proportion of traffic injured patients with evidence of alcohol abuse or hazardous drinking suggests that brief interventions by alcohol and drug counselors in emergency departments are a sensible option to addressing this important problem. The significance of this study is in the combination of the systematic collection of breath test and use of case-crossover design to estimate the risk of traffic injuries after alcohol consumption. The results provide convincing evidence to policy makers, health authorities and the media to help raise community awareness and policy advocacy toward the drinkdriving problem in Vietnam. The findings suggest an urgent need for a multi-sectoral approach to curtail drink-driving in Vietnam, especially programs to raise community awareness and effective legal enforcement. Furthermore, serving as a situation analysis, the thesis should inform the formulation of interventions designed to curtail drinking and driving in Vietnam and other developing countries.
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SINER, ANGELA. « In vivo metabolism of 7H-dibenzo[c.g.] carbazole (DBC) and benzo[a]pyrene (BaP) ». University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1014752553.
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Hann, Raiford Eugene. « Phase equilibria of the high-baria portion of the BaO-CaO-Al[subscript]2O[subscript]3 system ». Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/19105.
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Hoffmann, Cornelia. « Disziplinschwierigkeiten in der Schule : eine qualitative Einzelfallstudie mit einem gruppen- und bindungstheoretischen Schwerpunkt : das Beispiel einer Auffangklasse des Vereins BAJ in Bielefeld ». Wiesbaden VS, Verl. für Sozialwiss, 2009. http://dx.doi.org/10.1007/978-3-531-91484-8.
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Goosie, Marc S. « An Investigation into the Shift in Lie Acceptability in Children from Grades 3-12 ». Digital Commons @ East Tennessee State University, 2014. https://dc.etsu.edu/etd/2376.
Texte intégralRésumé :
In this study the goal was to determine if there was a shift in the extent to which children’s attitudes toward deception change as they age. Participants (N=278) enrolled in grades 3-12 completed a survey assessing their lie acceptability and other factors as potential variables associated with a prodeception attitude. Results indicated that greater lie acceptability was correlated with male children who had self-reported acts of bad behavior. Results also suggest that nontraditional family environments may increase one’s perception of the acceptability of lying. These findings provide potential predictors of the acceptability of lying in children and adolescents that offer insight into the development of antisocial attitudes, which may have practical implications regarding the timing of crucial interventions as to prevent the continuance and escalation of such behaviors in the future.
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Herrera, Claudia Natalia Lara. « Um método D-bar para estimar admitividade em 2-D através de tomografia por impedância elétrica ». Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3152/tde-16072013-120406/.
Texte intégralRésumé :
Propõe-se um novo método D-bar de Tomografia por Impedância Elétrica (TIE) para obter, simultaneamente, a condutividade e a permitividade de um domínio 2-D. O algoritmo direto baseia-se na prova de existência e unicidade do artigo de E. Francini [1]. A caracterização de tecidos biológicos é fortemente facilitada a partir do conhecimento de suas propriedades elétricas. Particularmente, nas aplicações médicas de TIE há grande interesse na permitividade, uma vez que, vários autores tem apresentado critérios para distinguir patologias baseados nesta propriedade, um exemplo constitui a determinação de presença ou ausência de sangue em líquidos acumulados no pulmão. Realizam-se testes com dados simulados numericamente e experimentais com o propósito de verificar e entender as propriedades, capacidades e limitações do algoritmo implementado. No caso dos testes numéricos, é desenvolvido um programa que resolve o problema direto da admitividade, o qual permite calcular conjuntos de dados de voltagem numéricos. São simulados dados aplicando padrões de corrente trigonométricos e por pares. As soluções exponencialmente crescentes do problema inverso são parte essencial do algoritmo e devem ser decompostas nas bases dos padrões de injeção de corrente. A compreensão da natureza destas decomposições para padrões de injeção trigonométricos e por pares, levou ao estabelecimento de especificações no projeto de um sistema de TIE para este algoritmo. Os resultados encorajadores numéricos e experimentais obtidos nas reconstruções de condutividade e permitividade, quanto à resolução espacial e às magnitudes, indicam que o algoritmo é promissor para uso clínico.This work proposes a new D-bar method of Electrical Impedance Tomography (EIT) for reconstructing the conductivity and permittivity simultaneously in a 2-D domain. The direct algorithm presented is based on the existence and uniqueness proof by E. Francini [1]. Biological tissue characterization is strongly facilitated by the knowledge of its electric properties. In EIT medical applications there is great interest in the permittivity as an additional property for distinguishing pathologies. For instance, the determination of presence or absence of blood in fluid accumulation in the lung. Numerical and experimental data tests are carried out in order to verify and understand the properties, capabilities and limitations of the implemented algorithm. A numerical phantom to solve the forward admittivity problem is developed which allows to simulate voltage data sets. Trigonometric and pairwise injection current patterns are applied. Exponentially growing solutions of the inverse problem are a key part of the algorithm, which have to be expanded in terms of the current patterns. Understanding the nature of these expansions for trigonometric and pairwise injection current patterns leads to a set of specifications in the design of an EIT system for this algorithm. The encouraging numerical and experimental results obtained in conductivity and permittivity reconstructions, regarding the magnitude and spatial resolution, indicate that the algorithm is promising for clinical use.
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Adkins, Drew David Wayne. « Studies of BaO – La2O3 – MgO – MnOn Compositional Space ». The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1440154953.
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Nguyen, Thom Tien. « Attitude, motivation, and consumption of seafood in Bacninh province, Vietnam / ». Tromsø : Norwegian College of Fishery Science, Universitetet i Tromsø, 2007. http://www.ub.uit.no/munin/bitstream/10037/1001/3/thesis.pdf.
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Vallejo, Miguel Fernando Montoya. « Reconstrução não-linear completa de imagens de tomografia por impedância elétrica utilizando o método D-bar 2D ». Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3152/tde-29072013-110500/.
Texte intégralRésumé :
Neste trabalho desenvolveu-se desenvolver uma versão sem linearizações do método D-bar para Tomografia por Impedância Elétrica (TIE). O problema inverso de TIE é não-linear e mal-posto. O algoritmo baseia-se na prova de existência e unicidade de Adrian Nachman [Ann. of Math. 143 (1996)] para domínios com distribuição de condutividade duas vezes diferenciáveis. O método faz uso de uma Transformada de Fourier não-linear chamada scattering transform, e o caráter mal-posto do Problema Inverso torna-se evidente no cálculo desta transformada, mais especificamente na determinação das soluções Complex Geometrical Optics (CGO). Atuais implementações práticas do método D-bar para padrões trigonométricos tem aproximado os valores na fronteira das soluções CGO por seu comportamento assintótico no cálculo da scattering transform, o que constitue uma linearização nesta etapa específica do método. Neste trabalho calcula-se a scattering transform a partir das soluções exponencialmente crescentes, o que implica calcular as funções Green de Faddeev, com o objetivo de encontrar imagens com maior resolução espacial e precisão nos valores de condutividade por ter resolvido o problema não-linear de forma completa. Dados de simulação numérica e experimentais usando padrões de injeção pula eletrodos e trigonométricos foram usados na avaliação do método. As imagens obtidas apresentam comportamento diferente em função do padrão de injeção utilizado. Do cálculo completo da transformada scattering resultam imagens com melhor resolução espacial. As imagens reconstruídas a partir de padrões de injeção trigonométricos apresentam também melhor resolução espacial comparadas as imagens reconstruídas a partir de padrões por pares, separados por três eletrodos.This work proposes to develop a version of the D-bar method linearization for Electrical Impedance Tomography (EIT). The inverse problem of EIT is both nonlinear and very ill-posed. The version of the D-bar method implemented here is based on the existence and uniqueness proof of Adrian Nachman [Ann. of Math. 143 (1996)]. The method relies on the use of a nonlinear Fourier transform called the scattering transform, and the inherent ill-posedness of the inverse conductivity problem becomes evident in the computation of the scattering transform, more specifically in the determination of the Complex Geometrical Optics (CGO) solutions. Current practical implementations of the D-bar method using trigonometric patterns have replaced the boundary values of the CGO solutions by their asymptotic behavior in the calculation of the scattering transform, which is a linearization in this particular step of the overall method. This work proposes to calculate the scattering transform from exponentially growing solutions, which implies the calculation of the Faddeev Greens function, with the goal of obtaining images with higher resolution and accuracy in the conductivity values because the full nonlinear problem is solved. Numerical and experimental data using pairwise and trigonometric current injection patterns were used to evaluate the performance of the method. Better spatial resolution is obtained from the complete computation of the scattering transform. Reconstructed images from trigonometric current patterns also show better spatial resolution compared to pairwise current injection patterns, skipping three electrodes.
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Steinebach, Mario, Katharina Thehos, Laura Richter, Ina Huke et Victoria Graul. « Newsletter für Freunde, Absolventen und Ehemalige der Technischen Universität Chemnitz 3/2013 ». Universitätsbibliothek Chemnitz, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-125362.
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Papadopoulou, Symela. « Velocity distribution in shallow open channel flow over square bar roughness ». Available from the University of Aberdeen Library and Historic Collections Digital Resources, 2009. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?application=DIGITOOL-3&owner=resourcediscovery&custom_att_2=simple_viewer&pid=58994.
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Britschgi, David Elsener-Elendt Janina. « Die Schweizer "Supernanny" : Erziehungsberatung zur Primetime : eine qualitative Fernsehanalyse zur Darstellung von Erziehungsberatung des Senders 3+ TV / ». Zürich : Departement Angewandte Psychologie, 2008. http://www.zhaw.ch/fileadmin/user_upload/psychologie/Downloads/Bibliothek/Arbeiten/BA/ba0017.pdf.
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Vanky, Charlotte, et Bente Strand. « Elevers möte och användning av olika uttrycksformer inom matematik : En litteraturstudie inom årskurs F-3 ». Thesis, Linköpings universitet, Institutionen för beteendevetenskap och lärande, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-144354.
Texte intégralRésumé :
Denna litteraturstudie uppmärksammar forskning i syfte att undersöka hur elever kan uttrycka sig inom matematiken genom användandet av olika uttrycksformer. Vidare menar forskningen att peka på elevers möte med olika uttrycksformer i matematikundervisningen samt betydelsen av abstrakta uttrycksformer för elevers utveckling inom algebraiskt tänkande. I litteraturstudien har databassökningar utförts genom SwePub, Ulrichsweb, ERIC och NOMAD. Resultatet av vår litteraturstudie visar att det är positivt för elevernas lärande och kunskapsutveckling att använda varierande uttrycksformer i matematikundervisningen. Det abstrakta inom matematiken går att förtydliga genom konkret material.
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Safiullin, Kayum. « Magnetic Resonance of Hyperpolarised Helium-3 at Low Magnetic Fields ». Phd thesis, Université Pierre et Marie Curie - Paris VI, 2011. http://tel.archives-ouvertes.fr/tel-00753219.
Texte intégralRésumé :
Dans ce travail nous avons étudié le problème du rapport signal à bruit (RSB) en IRM à très bas champ magnétique et exploré des applications potentielles en utilisant du gaz 3He hyperpolarisé. Nous avons comparé deux méthodes d'élargissement de bande passante sans perte de RSB : une contre-réaction et un couplage inductif de la détection. Nous avons mis en œuvre la contre-réaction, plus appropriée à très bas champ. Des mesures d'atténuation par diffusion dans un gaz d'3He en géométrie cylindrique ont été faites par échos multiples de spin ou de gradient dans une large gamme de conditions correspondant à la diffusion dans les voies aériennes des poumons. Un bas champ permet d'utiliser des faibles gradients sur des durées longues, sans influence de la susceptibilité des matériaux. Nos mesures fournissent un ensemble de données destiné à une comparaison directe avec des modèles théoriques et d'autres résultats publiés. Une nouvelle séquence (Slow Low Angle Shot, SLASH) est proposée pour l'imagerie de gaz à bas champ. Des séries d'images à 2D dans des fantômes montrent qu'elle offre une résolution d'image et un RSB meilleurs que pour une séquence FLASH. Par ailleurs, des cartes de diffusion apparente dans des poumons fixés de petit animal ont été obtenues à partir d'images 2D et 3D. Les résultats sont compatibles avec ceux des mesures globales de diffusion par échos de spin dans ces mêmes poumons, et sont similaires aux résultats in vivo publiés. Ces poumons fixés sont donc un fantôme commode et pertinent pour des études méthodologiques. Les mesures de diffusion en bas champ, insensibles aux effets de susceptibilité, ont été faites sur une large gamme de temps de diffusion.
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Laffez, Patrick. « Synthese et etude de materiaux ceramiques dielectriques pour resonateurs hyperfrequences appartenant aux systemes (bao) (ln#2o#3) (tio#2) (ln=sm, nd) ». Caen, 1992. http://www.theses.fr/1992CAEN2045.
Texte intégralRésumé :
Le travail a consiste a etudier les processus de synthese et les proprietes en hyperfrequences de ceramiques dielectriques appartenant aux systemes (bao)(sm#2o#3)(nd#2o#3)(tio#2). Dans un premier temps, nous avons etudie la physico-chimie de synthese par reaction en phase solide du compose (bao)#0#. #1#5(sm#2o#3)#0#. #1#5(tio#2)#0#. #7 a l'aide de diffraction x, atd, atg, dilatometrie, et observations microstructurales. Nous avons pu mettre en evidence l'influence des phases secondaires tio#2 et ba#2ti#9o#2#0 tant sur la physico-chimie du frittage que sur les proprietes physiques. Dans un second temps, une etude de diverses compositions des diagrammes ternaires (bao)(sm#2o#3)(tio#2) et (bao)(nd#2o#3)(tio#2) a ete entreprise dans le but de minimiser le role des phases secondaires. Ces deux etudes paralleles nous ont amene dans un troisieme temps a etudier des compositions du type (bao) ((sm#1#-#xnd#x)#2o#3)(tio#2). Ainsi nous avons pu minimiser le role des phases secondaires tout en maintenant des proprietes hyperfrequences equivalentes a celles obtenues pour des resonateurs ne contenant pas l'oxyde de neodyme. Enfin, divers essais d'ajouts, (mno#2, wo#3, cao), et des substitutions du baryum par du plomb ont ete effectuees. On a ainsi pu observer la potentialite des compositions (bao, pbo)(nd#2o#3)(tio#2) qui permettraient d'atteindre des performances elevees a base de compositions de faible cout et frittant a basse temperature. Des constantes dielectriques superieures a 80 ont ete obtenues, pour des produits facteur de qualite par la frequence de resonance superieurs a 9000 ghz, et pour des coefficients en temperature de la frequence de resonance compris entre 5 ppm/c
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Silvério, Valdir Anderson. « Estudo da evolução do tamanho de grão na laminação a quente de barras de aço médio carbono microligado ao vanádio - 38MnSiV5 ». Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-02062008-172934/.
Texte intégralRésumé :
Os aços microligados ao vanádio são usados em peças automotivas forjadas, tais como virabrequins e bielas. Através de equações matemáticas que descrevem a cinética de recristalização e de crescimento de grão, foi desenvolvida uma rotina em planilha para simular a evolução dos tamanhos de grão austeníticos durante os passes de laminação em função da temperatura, taxa de deformação, tempo entre passes e características do material. O resultado do tamanho de grão ferrítico calculado final, foi comparado com os tamanhos de grãos de amostras retiradas da laminação e de amostras realizadas por simulação física (ensaio de torção a quente). Esta comparação entre modelamento matemático e simulação física com o processo de laminação, demonstra que é possível calcular e descrever a evolução microestrutural e mostra que o principal mecanismo de controle do refino de grão envolvido em uma laminação de não planos com trens abertos é o de recristalização estática, para as condições existentes na usina onde foi efetuado o presente estudo.Microalloyed steels are used as forging stock for many automotive parts such as crankshafts and connecting rods. Using mathematical equations describing the recrystallization kinetics and grain growth, a spreadsheet has been developed to simulate the austenitic grain size evolution during bar rolling mill schedules as a function of temperature, strain rate and time between passes. The calculated ferritic grain size was compared with samples taken from the process and physical simulation (torsion testing). Comparison between mathematical modeling and physical simulation with the plant bar rolling mill process shows that it is possible to predict the microstructural evolution and confirm the main grain refinement control mechanism as being static recrystallization, under the conditions prevailing in the plant where this study has been carried out.
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Damásio, Lia Cruz Vaz da Costa. « Transplante experimental, subcutâneo e intraperitoneal, de ovário em suínos : estudo histomorfométrico e imunoistoquímico ». Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/5/5139/tde-23082011-145132/.
Texte intégralRésumé :
O transplante autólogo de tecido ovariano constitui alternativa relevante na preservação da fertilidade e da função hormonal ovariana em mulheres sujeitas à falência ovariana prematura e infertilidade, por causas malignas, tratamentos adjuvantes ou cirurgias. É a única opção para crianças, fase pré-puberal e para mulheres que não podem retardar a quimioterapia ou não podem ser submetidas à estimulação do ciclo. O transplante ovariano autólogo pode ser, quanto ao local de reimplantação, ortotópico ou heterotópico e, quanto à conservação, a fresco ou após o período de criopreservação. As várias etapas envolvidas neste transplante são estudadas mundialmente na atualidade, como a retirada e preservação do tecido ovariano, as técnicas de criopreservação, o local apropriado para o reimplante e as possibilidades de redução da perda folicular. A avaliação da apoptose - morte celular programada - é útil na avaliação da rejeição e viabilidade dos enxertos de transplantes estabelecidos na prática clínica, tanto autólogos como heterólogos. Com o intuito de utilizar animais de maior porte, conseguir seguimento de médio prazo e realizar os procedimentos cirúrgicos por via laparoscópica, padrão ouro em humanos, o presente estudo utilizou como modelo experimental fêmeas suínas, em idade reprodutiva, da raça Minipig. Este projeto teve como propósito avaliar a influência da criopreservação e do local de implante na qualidade e na viabilidade do transplante autólogo de ovário, a fresco e após criopreservação, no tecido celular subcutâneo e na região intraperitoneal peri-infundibular. Foram avaliados a quantidade e a densidade folicular dos implantes e os aspectos morfológicos e histomorfométricos, bem como a apoptose, por meio da imunoexpressão de proteínas proapoptóticas- Bax e antiapoptóticas-Bcl-2, além da Caspase 3-clivada, fase final das vias extrínseca e intrínseca dos mecanismos de apoptose.Quarenta animais foram divididos em cinco grupos: Controle com ooforectomia (Grupo I), ooforectomia e transplante a fresco subcutâneo (Grupo II), a ooforectomia e transplante fresco intraperitoneal (Grupo III), ooforectomia e transplante criopreservado subcutâneo (Grupo IV) e ooforectomia e transplante criopreservado intraperitoneal (GrupoV). Os resultados mostraram que independente da técnica empregada, havia folículos em desenvolvimento e corpos lúteos em todos os tecidos ovarianos transplantados; que a contagem de folículos antrais não degenerados foi menor nos grupos após criopreservação em relação ao grupo controle e que a imunoexpressão sugestiva de apoptose ocorreu em todos os grupos transplantados, sendo maior nos transplantes intraperitoneais. Concluiu-se que a técnica utilizada para o transplante de ovário e criopreservação foi viável no modelo suíno, em tecido celular subcutâneo e na região intraperitoneal peri-infundibular. O transplante autólogo heterotópico subcutâneo apresentou melhores taxas de apoptose que o transplante ortotópico.Autotransplantation of ovarian tissue is an important alternative to preserve fertility and hormonal ovarian function in women undergoing ovarian failure and premature infertilidade, because of cancer or surgery. It is the only option for infants, pre-pubertal patients and for women who can not delay chemotherapy or not may be subjected to stimulation of the cycle. The various steps involved in the transplant are studied worldwide today, as the removal and preservation of ovarian tissue, the techniques of cryopreservation, the appropriate site and mechanisms to reduce follicular loss. Assessment of apoptosis - programmed cell death-is useful in the study of the viability of the grafts and rejection of transplants established in clinical practice, both autologous and heterologous. In order to use larger animals, getting following medium term (over 21 days) and to perform surgical procedures by laparoscopy (gold standard in humans), this study used an experimental model sows, reproductive age, Minipig race. This project aims to evaluate the influence of cryopreservation and implantation site of the quality and viability of ovarian autografts, fresh and after cryopreservation, at subcutaneous site and at intraperitoneal site. We analyzed the quantity and density of follicular implants and the morphological and histomorphometric as well as apoptosis, by proteins immunoexpression antiapoptotic and proapoptotic. Forty animals were divided into five groups: Control with oophorectomy (Group I), oophorectomy and fresh transplantation to subcutaneous site (Group II), oophorectomy and fresh transplantation to intraperitoneal site (Group III), oophorectomy and transplantation of cryopreserved ovarian tissue to subcutaneous site (Group IV) and oophorectomy and transplantation of cryopreserved ovarian tissue to intraperitoneal site (Group V). We concluded that the autologous ovarian transplantation was feasible in the technical proposals, in subcutaneous and intraperitoneal site in the porcine model; that regardless of the technique, there was developing follicles and corpora lutea in all ovarian tissue transplanted; that antral non-degenerate follicle count was lower in groups after cryopreservation that in the control group and that the immunoexpression of apotposis occurred in all transplanted groups, more evident in intraperitoneal transplants
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De, Poli Emma. « The gene mapping of Senegalese sole (S. senegalensis) ». Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/15863/.
Texte intégralRésumé :
The Senegalese sole (S. senegalensis) is a common flatfish, distributed over the eastern Atlantic coast from the Northern part of Senegal. Senegalese sole aquaculture has aroused great interest in the marine aquaculture in Spain and Portugal because of its relatively rapid growth rate, but it presents limits due to the poor reproduction of captive breeders in many facilities. In fact gonad development during sexual maturation results in major growth reduction, and increased susceptibility to diseases (Felip et al., 2006). Senegalese sole has 42 chromosomes and an XX/XY chromosome system for sex determination, while related species show the ZZ/ZW system. In S. senegalensis, these problems are aggravated because of the lack of knowledge concerning sex.
This study fits into a detailed project of Senegalese sole knowledge, promoted by University of Cádiz, providing new information about the karyotype characterization, the chromosome structure of certain genes involved in sex determination and sexual differentiation processes, which may be relevant for improving the commercial production of this species. This piece of information not only helps to understand the development and evolutionary mechanism in vertebrates, but will also contribute to improving the production of target species for aquaculture.
For this purpose, several bacterial artificial chromosome (BAC) clones that contain candidate genes involved in such processes (Vitellogenin, Otospiralin, R-spondin-1, Steroidogenic Factor1 and Tetkin-2) were analyzed and compared, where possible, with the same genes in other species.
In this study it was possible to describe a part of those four genes, using 3’ RACE method. The BAC-FISH results showed the position of different genes in different chromosome, to improve the knowledge of Senegalese sole karyotype. In particular, the localization of steroidogenic factor 1 (SF1) in the chromosome 1 that is involved in the sex determination.
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ZIANE, MOHAMED SAID. « Etude microstructurale et thermocinetique de la formation de la phase yba#2cu#3o#7#-# par interdiffusion dans le systeme y#2o#3-cuo-bao ». Paris 11, 1996. http://www.theses.fr/1996PA112194.
Texte intégralRésumé :
Ce travail est une etude thermocinetique et microstructurale de la formation et de la croissance de phases par interdiffusion dans le systeme pseudo-ternaire y#2o#3-cuo-bao. Un interet particulier a ete porte aux phenomenes qui gouvernent la formation et la croissance de la phase 123 (yba#2cu#3o#7#-#). Les materiaux utilises dans les etudes d'interdiffusion (bacuo#2#+#, bacu#1#+#xo#2#+#y et y#2bacuo#5) ont ete elabores par deux voies differentes: reaction a l'etat solide procede sol-gel l'obtention de materiaux massifs a necessite la mise au point de procedures de frittage. Les poudres ont ete compactees a temperature ambiante sous pression isostatique de 10 kbars. Dans le cas des composes riches en yttrium (y#2bacuo#5 par exemple), on a fait suivre le frittage par un fluage-forgeage ce qui a permis d'accroitre considerablement la densite des echantillons. Deux types de couples d'interdiffusion ont ete realises et etudies a des temperatures egales ou inferieures a 950c: 1 bacuo#2#+#/y#2bacuo#5 et bacuo#2#+#/y#2o#3 2 (bacuo#2#+# + xcuo)/y#2bacuo#5 et (bacuo#2#+# + xcuo)/y#2o#3 dans le premier cas la diffusion conduit a la formation de phases riches en baryum telles que: yba#4cu#3o#x, yba#6cu#3o#x, yba#8cu#5o#x et yba#9cu#5o#x. Dans le second cas, ou a ete introduit un exces de cuivre, la phase formee apres interdiffusion est la phase 123. Les chemins de diffusions correspondants ont ete representes dans des diagrammes ternaires. On en deduit les reactions a l'etat solide qui semblaient prendre place. Une etude detaillee de ces diagrammes permet de mettre en evidence des ecarts de composition au cours de l'interdiffusion entre les phases obtenues et leur composition ideale. La germination de la phase 123 est peut etre favorisee par la phase liquide presente dans ces couples a haute temperature. Des observations par microscopie electronique en transmission faites sur des couples en couches minces semblent en particulier montrer que les joints de grains le long desquels le liquide migre rapidement, sont des sites de germination preferentiel. Apres qu'une couche 123 se soit formee elle fait obstacle a la diffusion du liquide et la croissance se poursuit par diffusion a l'etat solide. Les cinetiques de croissance des phases 143 et 123 ont ete etudiees ; elles suivent des lois paraboliques en fonction du temps. Des coefficients de diffusion effectifs dans la phase 123 ont ete deduit a partir des constantes paraboliques en utilisant la relation de nerst-einstein. La phase 123 qui apparait dans les couples (bacuo#2#+# + xcuo)/y#2o#3 est de structure columnaire et texturee. La texture, etudiees a partir de diagrammes d'electrons retrodiffuses, est telle que les plans (001) ou (a,b) sont paralleles a la direction de diffusion et de croissance de la phase 123. L'origine de la texture peut etre attribue a un mecanisme dans lequel les systemes de contraintes a caractere fortement bidimensionnel, induites par l'interdiffusion joue le role essentiel
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Maciel, Alex Roda. « Automação do processo de corte e dobra de armaduras para estruturas de concreto integrada ao processo BIM ». Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/3/3153/tde-28082018-142552/.
Texte intégralRésumé :
A consolidação do processo de Modelagem da Informação da Construção (BIM) tende a contribuir para o aumento da eficiência da indústria da construção civil, fomentando novos fluxos de trabalho e permitindo o reuso de informações ao longo do ciclo de vida dos empreendimentos. Apesar do potencial de integração e automação associados ao processo BIM, o uso das informações digitais contidas no modelo para facilitar a pré-fabricação de produtos para a construção mostra-se incipiente. Nota-se que emprego da fabricação digital encontra obstáculos sobretudo em setores que atuam de modo segregado, e que por isto mesmo demandam sinergia, bem como o uso de normas e padrões que possibilitem a interoperabilidade e reuso das informações geradas nas fases anteriores a fabricação. Neste contexto, foi feita uma análise do uso da fabricação digital aplicada ao processamento industrial de aço para estruturas de concreto armado (corte e dobra). Embora os fabricantes que atuam neste setor possuam suporte a interface digital com os demais agentes, a configuração de sua cadeia de produtiva, bem como os processos tradicionalmente adotados, promovem a ocorrência de ilhas de automação ligadas por transferência manual e reentrada de dados. Como forma de reduzir a intervenção manual para a transcrição dos dados, propõe-se o uso do esquema de dados Industry Foundation Classes (IFC) na fabricação digital de componentes de armadura. Este trabalho tem por objetivo apresentar uma solução técnica, baseada no esquema IFC, aos requisitos de troca de informação necessários no fluxo de trabalho proposto. Com base nos requisitos de troca identificados por meio do método Information Delivery Manual (IDM), apresenta-se como essas informações podem ser mapeadas e qual o subconjunto de dados necessários à fabricação digital baseada no esquema IFC4. Por fim, apresenta-se a documentação e validação da solução técnica desenvolvida de acordo com o método Model View Definition (MVD) e com o uso da ferramenta ifcDoc. Após a realização de testes com base no esquema IFC4 foi constatada a viabilidade para recuperação dos dados contidos no modelo. Entretanto também foi identificada a carência de ferramentas comerciais que suportem tal funcionalidade.The consolidation of Building Information Modeling (BIM) possibly contributes to the increase of the efficiency in the construction industry, by fostering new workflows and data reuse throughout projects life cycle. Despite the potential for integration and automation associated with BIM, the use of the digital information contained in the model to facilitate prefabrication of construction products is still incipient. The digital fabrication finds obstacles in sectors that act in a segregated manner, henceforth needs standard adoption to allow reuse of the information generated in the phases prior to production. In this context, it was analyzed the use of digital fabrication applied to the industrial processing of reinforcement bars for concrete structures (rebar cutting and bending). Although the fabricators who act in this sector already have support to the digital interface with other agents, the supply chain configuration adopted by the Brazilian market, as well as the traditional paper-based processes employed, promote the occurrence of \"islands of automation\" connected by manual data transfer. In order to reduce the need for manual intervention for data re-interpretation and re-entry, it is proposed to use the Industry Foundation Classes (IFC) data schema to promote the digital interface between the reinforcing bar supply chain stakeholder\'s. This work aims to present an IFC-based technical solution to the fabricator\'s information requirements by means of the Information Delivery Manual (IDM) and Model View Definition (MVD) standards. On the basis of the exchange requirements specified by rebar fabricator through IDM method, it is presented the IFC schema subset entailed and how this information can be mapped in order to allow the use of IFC on the cut & bend rebar supply chain. Finally, the technical solution was documented in an MVD and validate with the ifcDoc tool. After conducting validation tests based on the IFC4 schema, it was verified the viability to recover the data contained in the model. However, the lack of commercial tools that support such functionality has also been identified.
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Sudoh, K., Y. Ichino, Y. Yoshida, Y. Takai, I. Hirabayashi, 祐亮 一野 et 隆. 吉田. « Magnetic field dependence of critical current density in Sm/sub 1+x/Ba/sub 2-x/Cu/sub 3/O/sub 6+/spl delta// films prepared by pulsed laser deposition ». IEEE, 2003. http://hdl.handle.net/2237/6742.
Texte intégral
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Kolli, T. (Tanja). « Pd/Al2O3 -based automotive exhaust gas catalysts:the effect of BaO and OSC material on NOx reduction ». Doctoral thesis, University of Oulu, 2006. http://urn.fi/urn:isbn:9514280563.
Texte intégralRésumé :
Abstract
The aim of the thesis was to find new information on the effect of BaO and oxygen storage capacity material on NOx reduction. A total of nine different kinds of Pd/Al2O3-based metallic monoliths were studied. Promoters such as oxygen storage capacity material (OSC material in our case Cex-1ZrxO2 mixed oxides) and stabilisers such as barium (BaO) were added into the catalyst alone or together to improve catalyst properties such as catalytic activity, selectivity, and thermal stability.
The key aspects in this thesis can be divided into four parts. First, the behaviour of NO reduction and CO as well as C2H4 oxidation over Pd/Al2O3-based catalysts in rich, stoichiometric and lean conditions were studied. Secondly, the effect of BaO and the OSC material in NO reduction was considered. Thirdly, the preparation procedure, i.e. the addition order of BaO, OSC material, and Pd on the catalyst was considered. Finally, the effect of ageing on the behaviour of catalysts was investigated.
Several characterization methods (in situ DRIFT, catalytic activity measurements, N2 physisorption, CO chemisorption, dynamic oxygen storage capacity measurements, and X-ray diffraction (XRD)) were utilised to find answers to the behaviour of these catalysts in the studied model reactions. The Rapid Ageing Hot in Laboratory (RAHLAB) method was used to age the catalyst.
First, it was demonstrated that the CO and hydrocarbon oxidation and NO reduction reactions over the Pd/Al2O3-based catalyst behave differently. NO reduction and CO and hydrocarbon oxidation reactions were dependent on the reaction conditions and temperatures. Secondly, the effect of OSC and BaO on NO reduction was studied separately. In the case of OSC material, it was observed that the OSC material has an effect on NO reduction as well as on CO and C2H4 oxidation. In the case of BaO, it was observed that BaO has a positive effect on NO reduction as well as CO and C2H4 oxidation especially in rich conditions. Thirdly, the effects of the addition order of OSC and BaO on the catalyst was studied separately. It was shown that these have an effect on NO reduction, especially after ageing. First, on the fresh Pd/Al2O3 catalyst it was observed that the addition order of OSC on the catalyst has not an influence on catalyst performance. The effect of the BaO addition order on the Pd/OSC/Al2O3-based catalyst is found to be insignificant, especially, after the ageing process. Furthermore, it is observed that the effect of RAHLAB ageing was that the catalyst lost its catalytic activity, stability, and selectivity.
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Neves, Renato Ramirez Viana. « Desempenho de defensas rodoviárias sujeitas ao impacto de automóveis ». Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/3/3151/tde-01082013-162732/.
Texte intégralRésumé :
As defensas rodoviárias têm a finalidade de redirecionar com segurança um veículo fora de controle de uma colisão frontal ou trajetória mais perigosa. Secundariamente, a absorção de energia através da deformação do sistema de contenção ou outro método de dissipação da energia de impacto é ressaltado como um benefício em prol da segurança dos ocupantes. Considerando as premissas anteriores e os índices de severidade ao ocupante ASI, THIV e PHD, os desempenhos de uma defensa metálica e outras defensas de concreto são então classificados. Além disso, investiga-se o mecanismo de falha das conexões parafusadas e a sua influência no resultado do impacto de um automóvel leve contra uma defensa metálica. Importância é dada à modelagem do comportamento do material da defensa metálica sob baixas e altas taxas de deformação. Dessa forma, a necessidade de avaliar as propriedades dinâmicas do material motivou o projeto e construção de uma Barra de Hopkinson para testes de tração e compressão até 5000s-1. Adicionalmente, um modelo analítico simplificado da defensa metálica sob ação de uma força estática foi equacionado para validar um modelo em elementos finitos. Um estudo paramétrico da falha da conexão parafusada foi levantado através de diversas simulações estáticas e também do impacto de um veículo leve em uma defensa metálica de acordo com a norma EN 1317. Os resultados das simulações de impacto utilizando um modelo de veículo leve e diferentes sistemas de contenção foram comparados em função dos índices de severidade ao ocupante, indicando que a defensa metálica é mais segura do que uma defensa de concreto com perfil New Jersey ou vertical.The main function of a road guardrail is to redirect an out of control vehicle avoiding a frontal collision or a dangerous veering off the road trajectory. Secondarily, the energy absorption measured by barrier deformation or any other energy dissipation method is beneficial to the car occupant safety. Considering the previous tasks and some severity occupant index like ASI, THIV and PHD, the performance of a guardrail and other concrete barriers are classified. Besides, it is investigated the fail mechanism of bolted connections and its influence on the guardrail impact result of an automobile. Special attention was taken into the material behavior modeling under low and high strain rates. Thereby, the need of accessing dynamic material properties motivated the design and manufacture of a Hopkinson Bar set-up for tension and compression tests up to 5000s-1. In addition, a simplified analytical model of a guardrail subjected to a static force was settled in order to validate a guardrail finite element model. A parametric study of the bolted connection failure was performed through several impact simulations of a light car model and a guardrail according to EN 1317 standard. The impact simulation results using a light vehicle car model and different barriers types were compared through the occupant severity index showing that the guardrail is a safer system than concrete barrier with New Jersey or vertical profile.
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Junior, João de Araújo. « Estudo da degradação parcial de filmes de blendas de poli(tereftalato de butileno-co-adipato de butileno) e poli(ácido láctico) no processo de compostagem doméstica ». Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/3/3133/tde-10112016-101541/.
Texte intégralRésumé :
Neste trabalho, foram estudadas blendas de poliésteres sintéticos e de fonte renovável - poli(tereftalato de butileno-co-adipato de butileno) - PBAT e poli(ácido láctico) - PLA, respectivamente, utilizados em sacolas de supermercado. Amostras destes materiais foram pesadas e enterradas em solo simulado por quatro meses para simular uma compostagem tradicional. As amostras foram então analisadas por Calorimetria Exploratória Diferencial (DSC), Termogravimetria e Termogravimetria Derivada (TG e DTG, incluindo uma Análise Cinética não isotérmica comparativa com sacolas de PE aditivadas com agente pró-degradante, Espectroscopia Vibracional Raman com Transformada de Fourier (FT-Raman), Difração de Raios X e Cromatografia de exclusão por tamanho. Embora não tenha havido perda de massa significativa no período do envelhecimento por compostagem tradicional, foram constatadas importantes alterações estruturais nas amostras, tais como a redução nas energias de ativação (Ea) para os processos de decomposição térmica, a redução na intensidade da banda relativa ao estiramento da carbonila presente nos poliésteres e também uma drástica redução da massa molecular dos polímeros. Em paralelo, a aceleração do processo de biodegradação com Vermicompostagem foi investigado, com resultados bastante promissores, incluindo a degradação total da amostra após um tratamento prévio de exposição à luz solar.In this study, blends of the synthetic polyester poly(butylene adipate-cotherephtalate) - PBAT - and the natural one poly(lactic acid) - PLA - used as biodegradable plastic shopping bags were studied. Samples of these materials were weighed and buried in simulated soil for four months to simulate domestic composting. These samples were then studied by Differential Scanning Calorimetry (DSC), Thermogravimetry (TG, including a comparative non-isothermal Kinetic Analysis with PE shopping bags containing prodegradation agents), Transformed Fourier Raman Vibrational Spectroscopy (FT-Raman), Wide Angle X-Ray Diffraction (WAXD) and Gel Permeation Chromatography (GPC). It was observed that even though there was no significant mass loss in the period of the ageing when using conventional home composting, important structural changes were detected in the samples, such as the reduction of activation energies (Ea) for the thermal decomposition processes, the reduction of intensity of the peak associated with the stretching of the carbonyl present in both polyesters and also a dramatic decrease in molecular weights. In parallel, the acceleration of the biodegradation process with vermicomposting was investigated, with very promising results, including the total disintegration of the samples when submitted to a previous treatment of sun light exposure.
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Cavalcanti, Paulo de Sá Pereira. « Investigação experimental da fadiga ao cisalhamento em lajes de pontes com pré-lajes ». Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3144/tde-28022011-170148/.
Texte intégralRésumé :
Um número significativo de pontes têm sido construídas na forma de grelhas de vigas pré-moldadas, sobre as quais apoiam-se pré-lajes com posterior concretagem de capa, finalizando a execução das lajes das mesmas. Esse processo construtivo tem sido largamente utilizado tendo em vista a racionalização da construção dispensando o uso de cimbramentos, abreviando consideravelmente os prazos de construção e consequentemente reduzindo os custos. Todavia no desenvolvimento do projeto, sabe-se que essas lajes são elementos altamente suscetíveis à fadiga e, tendo-se em vista a existência de concretagem em duas etapas (pré-laje e capa final) e concretos de idades diferentes, geram-se dúvidas obre o comportamento desta interface com relação às cargas dinâmicas atuantes no decorrer da vida útil da obra. A escassez de estudos ou pesquisas relacionadas a essa questão, levaram à realização do presente trabalho, de cunho experimental, e com o objetivo de se estudar o comportamento desses elementos submetidos às cargas de fadiga e as suas resistências finais no que se refere às cargas de ruptura antes e depois de fatigadas. Foram ensaiadas 9 lajes de concreto sendo 6 lajes com rugosidade normal (saliência dos agregados brita 1) e 3 com baixa rugosidade (alisamento com espátula de madeira). Não foram identificadas rupturas por fadiga e a resistência das lajes fatigadas se mantiveram, quando levadas a ruptura no final dos ensaios, no mesmo nível daquelas não fatigadas.A significant number of bridges have been built in the form of grids of pre-cast beams on which pre-slab are supported, with posterior concreting of concrete cover, completing the execution of the slabs. This construction process has been widely used in order to rationalize the construction without shoring, shortening considerably the time of construction and thereby reducing costs. However in developing the project, it is known that these slabs are elements highly susceptible to fatigue and, keeping in mind the existence of concrete in two stages (pre-slab and final cover) and different ages, doubts about the behavior of this interface with respect to dynamic loads acting over the lifetime are generated. The scarcity of studies and researches related to this issue led to the realization of this experimental work, in order to study the behavior of these elements subjected to fatigue loading and their final resistance in relation to the failure load before and after fatigue loading. Tests were made in 9 concrete slabs, 6 with usual surface roughness (salience of crushed aggregates 1) and 3 with low roughness (smoothing with wooden spatula). It was verified that no rupture due to fatigue loading were identified and the resistance of the slabs submitted to fatigue loading remained on the same level of those not fatigued, when carried to cracking at the end of the tests.
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OBRADOVIC, SUSANNE. « Definition d'une matrice vitroceramique pour composites thermostructuraux a fibres sic dans le systeme bao-cao-al#2o#3-sio#2 : etude de la cristallisation et de la densification ». Rennes 1, 1996. http://www.theses.fr/1996REN10048.
Texte intégralRésumé :
L'objet de ce memoire porte sur la cristallisation dans le systeme quaternaire, cao-bao-al2o3-sio2 (bcas) afin d'elaborer une matrice vitroceramique renforcee par un renfort de type sic. Le domaine de composition choisi permet la cristallisation en proportion variable de deux phases majoritaires, le celsian monoclinique baal2sio8 ( = 2,3 10-6c-1) et l'anorthite triclinique caal2sio8 ( = 4,5 10-6c-1) ce qui permet d'adapter le coefficient de dilatation thermique de la matrice a celui du renfort et ainsi d'intervenir sur la tenue mecanique du composite. De plus, cette matrice tres refractaire doit conferer au composite une temperature d'application tres elevee (t 1300c). On a d'abord montre que la formation de la phase celsian, impossible dans le systeme bas pur, est favorisee pour des compositions riches en cao. Lorsque la proportion de bao augmente, la quantite de celsian s'accroit jusqu'a une composition bao/(cao + bao) = 0,5 pour laquelle la phase hexacelsian metastable ( = 8 10-6c-1) cristallise preferentiellement au celsian. Cette evolution cree un minimum pour le coefficient de dilatation thermique de la vitroceramiques ( = 4. 10-6c-1) et s'accompagne en parallele de modification microstructurales independantes de la nature des phases cristallisees. Ensuite, la densification de ces matrices est possible a basse temperature (t 930c), entre les temperatures de transition vitreuse et de cristallisation (porosite ouverte < 1%). Elle est encore amelioree par l'addition de certains oxydes, notamment b2o3 et la2o3, sans alterer la nature des phases cristallisees. Enfin, la matrice de composition bao/(cao + bao) = 0,33 presentant le plus faible coefficient de dilatation thermique et une bonne aptitude a la densification a permis d'elaborer un composite a fibres longues sic(o) avec une porosite inferieure a 1%. La presence des fibres favorise la cristallisation de la phase celsian au detriment de celle d'anorthite.
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Micheli, Giancarlo Barbosa. « Análise numérico-experimental do impacto em chapas de alumínio aeronáutico ». Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3151/tde-09022009-161857/.
Texte intégralRésumé :
A interação dinâmica resultante do impacto de esferas de aço contra chapas de alumínio é estudada através da representação numérica de testes experimentais, os quais imitam freqüentes colisões de pequenos fragmentos contra a fuselagem de aeronaves. Importância é dada à modelagem do comportamento visco-plástico do material da chapa, o que conduz à proposição de uma modificação no método de caracterização dinâmica mecânica de material, realizado através de um equipamento denominado Barra de Hopkinson. Adicionalmente, a influência de possíveis erros na seleção de parâmetros de simulação, relacionados ao contato, amortecimento estrutural e principalmente ao material, é discutida através de análises numéricas de sensibilidade. Testes de impacto foram conduzidos de forma a se obter a velocidade balística das chapas. O deslocamento máximo permanente das chapas a baixas velocidades também foi medido. O método de caracterização dinâmica de material proposto é então avaliado pela comparação dos resultados de simulações numéricas frente aos dados experimentais obtidos nos testes de impacto. As predições de deslocamento máximo permanente, para testes sem perfuração da chapa, e de velocidade balística, para testes de perfuração total, indicaram uma boa concordância numérico-experimental, respeitadas as observações realizadas acerca dos parâmetros envolvidos.Dynamic interaction present on impact of steel spheres against aluminum panels is studied through a numerical model of experimental tests, which reproduce common collisions of small debris against airplane fuselages. This thesis emphasizes the panel-material visco-plastic behaviour modeling, which leads to a modification of the material dynamic characterization method, based on a Split Hopkinson Pressure Bar. Influence of possible errors in some numerical simulations parameters, related to contact, structural damping and material behaviour is also discussed by sensitivity numerical analyses. Impact tests were conducted to obtain the ballistic velocity of the panels. Also, the final maximum plate deformation at low velocities was measured. The proposed dynamic characterization method is explored by comparing the numerical simulation and the impact tests. The predicted maximum impact point displacement, for no perforation cases, and the ballistic velocity, for total perforation tests, present a good numerical-experimental agreement, bearing in mind the observations about the various used parameters.
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Santos, Diego Fernando González. « Caracterização microestrutural, mecânica e durante o processo de torneamento de aços ABNT 1045 e ABNT 1145 para avaliação do efeito do enxofre ». Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/3/3151/tde-18082008-160331/.
Texte intégralRésumé :
O presente trabalho trata sobre a influência do teor de enxofre, em quatro aços com uma composição química similar (famílias ABNT 1045 e ABNT 1145), na microestrutura, nas propriedades estáticas, dinâmicas e nos processos de usinagem. Para esta análise foi feita uma caracterização microestrutural de cada material para determinar parâmetros tais como a fração de inclusões de sulfeto de manganês (MnS) e a fração volumétrica de perlita. Também foi feita uma caracterização mecânica que consistiu em ensaios estáticos mediante o ensaio de tração e dureza, e um ensaio dinâmico utilizando a barra de Hopkinson, com o objetivo de observar o comportamento das inclusões e do próprio material quando deformado com altas e baixas taxas de deformação. Para a caracterização durante a usinagem destes aços foram feitos ensaios de torneamento para avaliar as forças de corte e de avanço em velocidades de corte de 190, 110, 45 e 15 m/min. A rugosidade dos corpos-de-prova também foi medida. Os resultados obtidos nos ensaios de torneamento e da caracterização microestrutural foram analisados estatisticamente para observar variações do comportamento das forças de usinagem de cada aço sob diferentes condições de velocidade de corte, e tentar correlacionar esse comportamento com a microestrutura do material. Observou-se que o aço 1045-A apresentou forças de usinagem (força de corte e força de avanço) superiores que os demais aços, já o aço que apresentou menores forças de usinagem foi o aço 1145-B. Isto é apenas uma tendência, devido que não houve diferença estatística que avaliasse esse comportamento. Também se observou que a rugosidade é um parâmetro que depende mais da velocidade de corte que da distribuição e/ou morfologia das inclusões. Evidenciou-se a formação de aresta postiça de corte (APC) numa faixa de velocidades (15-50 m/min), o que influenciou na rugosidade para estas condições de velocidades. Verificou-se que o comportamento das inclusões em baixas taxas de deformação é de caráter frágil, entanto que em altas taxas seu comportamento é plástico e deforma junto com a matriz.This work deals with the sulfur influence on the microstructure and on the static, dynamic and machining behavior of four steels with similar chemical composition. (ABNT 1045 and ABNT 1145). Microstructure characterization of the materials was performed in order to obtain the area fraction of the phases of perlite and sulfide inclusions. A mechanical characterization of the materials was also performed, consisting in a set of static (tension and hardness test) and dynamic tests (Split Hopkinson Pressure Bar Test) with the objective of observing the deformation behavior of the sulfide inclusions at low and high strain rates. Various machining tests were carried out at different cutting speeds, namely 190, 110, 45 e 15 m min-1, for obtaining the cutting forces during de machining process. After the machining tests, the roughness of the steels was also measured. Later on, the results of the different experiments were analyzed with statistical tools and then compared to establish a correlation between the cutting forces and microstructure. The higher cutting forces were registered for the 1045-A steel and the lower for the 1145-B steel. However, this was considered merely a trend given that no statistical difference was found to support any conclusion. It was also observed a stronger roughness dependency on the cutting speed than in the distribution and/or morphology of the inclusions. The steels were observed to form a built-up edge (BUE) in a range of cutting velocities of 15-50 m/min. This phenomenon affected the roughness for these cutting velocities. The behavior of the sulfide inclusions was observed to be brittle under low strain rates. On the other hand, under high strain rates, a plastic deformation behavior was observed with inclusions participating in the plastic flow of the metal matrix.
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LAURETTA, ELIANA. « POLICY PROPOSAL ON THE FINANCE AND GROWTH RELATIONSHIP : UNDERSTANDING THE SWITCH FROM "VIRTUOUS" TO "BAD" CYCLES ». Doctoral thesis, Università Cattolica del Sacro Cuore, 2014. http://hdl.handle.net/10280/3955.
Texte intégralRésumé :
Studi condotti sulla crisi finanziaria del 2007-09 e la recessione economica hanno evidenziato l’inadeguatezza delle teorie predominanti e la loro inefficacia nel proporre adeguate soluzioni di policy. La presenza di moneta bancaria nell’economia e di un sistema finanziario caratterizzato da innovazione finanziaria e speculazione modificano profondamente la natura stessa del processo di credit creation. Una nuova prospettiva sulla relazione tra finanza e crescita economica necessita essere sviluppata cercando di colmare le lacune esistenti tra New Growth Theory e Evolutionary Theory, come J.A. Schumpeter (1934) e altri studiosi hanno evidenziato. I fattori strutturali sono alla base della persistente instabilita` finanziaria nell’economia. Questo studio tenta di spiegare l’ipotesi che sta alla base dell’intera analisi circa il passaggio avutosi nell'impianto strutturale dell'economia da un virtuous cycle ad un bad cycle, e dimostrare l’esistenza di cio` che definiamo wealth trap, la quale e` ipotizzata essere conseguenza di un sistema finanziario tecnologicamente avanzato, ma non socialmente avanzato. Un modello non lineare ad Agenti (AMB) chiamato BFSE (Based-line Financial System Economy) mostra , tramite la sperimentazione sul modello ICEACE(Erlingsson et al., 2011), evidenze sulla centralita` del sistema finanziario e dell’esistenza del bad cycle. Una discussione sulle macroprudential policies e le politiche strutturali e` introdotta.Studies of the 2007-09 credit crisis and the resulting recession have revealed the inadequacy of the predominant theoretical frameworks and their failure to propose adequate policy solutions. The presence in the economy of bank money and a financial system characterized by financial innovation and speculation changes the nature of credit creation. As J.A. Schumpeter (1934) and others scholars have recognized, a new perspective on the financial-growth relationship needs to be developed by filling the gaps in New Growth Theory and Evolutionary Theory - two Sons of Schumpeter - and in some way combining them. Structural factors are at the bottom of the persistence of the financial instability in the economy. The goal of this research is to explain the main hypothesis of the historical passage of the economy from a virtuous to a bad cycle and to show the existence of the wealth trap, which is a consequence of a high-technologically advanced financial system within the economic system. A non-linear ABM (Agent Based Model) called BFSE provides, through experimentation using ICEACE model (Erlingsson et al., 2011), interesting evidences of the centrality of the financial system and the bad cycle. Macroprudential and structural policies are introduced.
49
LAURETTA, ELIANA. « POLICY PROPOSAL ON THE FINANCE AND GROWTH RELATIONSHIP : UNDERSTANDING THE SWITCH FROM "VIRTUOUS" TO "BAD" CYCLES ». Doctoral thesis, Università Cattolica del Sacro Cuore, 2014. http://hdl.handle.net/10280/3955.
Texte intégralRésumé :
Studi condotti sulla crisi finanziaria del 2007-09 e la recessione economica hanno evidenziato l’inadeguatezza delle teorie predominanti e la loro inefficacia nel proporre adeguate soluzioni di policy. La presenza di moneta bancaria nell’economia e di un sistema finanziario caratterizzato da innovazione finanziaria e speculazione modificano profondamente la natura stessa del processo di credit creation. Una nuova prospettiva sulla relazione tra finanza e crescita economica necessita essere sviluppata cercando di colmare le lacune esistenti tra New Growth Theory e Evolutionary Theory, come J.A. Schumpeter (1934) e altri studiosi hanno evidenziato. I fattori strutturali sono alla base della persistente instabilita` finanziaria nell’economia. Questo studio tenta di spiegare l’ipotesi che sta alla base dell’intera analisi circa il passaggio avutosi nell'impianto strutturale dell'economia da un virtuous cycle ad un bad cycle, e dimostrare l’esistenza di cio` che definiamo wealth trap, la quale e` ipotizzata essere conseguenza di un sistema finanziario tecnologicamente avanzato, ma non socialmente avanzato. Un modello non lineare ad Agenti (AMB) chiamato BFSE (Based-line Financial System Economy) mostra , tramite la sperimentazione sul modello ICEACE(Erlingsson et al., 2011), evidenze sulla centralita` del sistema finanziario e dell’esistenza del bad cycle. Una discussione sulle macroprudential policies e le politiche strutturali e` introdotta.Studies of the 2007-09 credit crisis and the resulting recession have revealed the inadequacy of the predominant theoretical frameworks and their failure to propose adequate policy solutions. The presence in the economy of bank money and a financial system characterized by financial innovation and speculation changes the nature of credit creation. As J.A. Schumpeter (1934) and others scholars have recognized, a new perspective on the financial-growth relationship needs to be developed by filling the gaps in New Growth Theory and Evolutionary Theory - two Sons of Schumpeter - and in some way combining them. Structural factors are at the bottom of the persistence of the financial instability in the economy. The goal of this research is to explain the main hypothesis of the historical passage of the economy from a virtuous to a bad cycle and to show the existence of the wealth trap, which is a consequence of a high-technologically advanced financial system within the economic system. A non-linear ABM (Agent Based Model) called BFSE provides, through experimentation using ICEACE model (Erlingsson et al., 2011), interesting evidences of the centrality of the financial system and the bad cycle. Macroprudential and structural policies are introduced.
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Caixeta, Edielce Cristina. « Investigação experimental da fadiga em lajes de pontes com ou sem pré-lajes ». Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3144/tde-20102010-151801/.
Texte intégralRésumé :
As lajes dos tabuleiros de pontes de concreto armado, sejam elas maciças ou executadas com pré-lajes, são elementos estruturais suscetíveis à fadiga, devido às ações a que são submetidas. As pré-lajes, pelo fato de serem resultantes da junção de dois concretos diferentes, torna-se ainda mais suscetível à fadiga. Este trabalho apresenta estudos, ensaios e análise de resultados a respeito do comportamento à fadiga das lajes de pontes de concreto, sejam as maciças ou as executadas com pré-laje, armadas com barras ou telas soldadas. Foram realizados ensaios de fadiga de barra ao ar CA50 f10 mm isoladas e em telas para a construção da Curva de Wöhler nas condições brasileiras. Além disso, foram ensaiadas 23 lajes de concreto, sendo 6 lajes maciças e 17 executadas com prélajes, montadas com diversas configurações de armadura, submetidas a ensaios estáticos e dinâmicos. As configurações de armaduras adotadas nas lajes da pesquisa foram baseadas nas utilizadas com freqüência neste tipo de elemento das pontes, escala ½. Um dos principais motivos que levaram ao desenvolvimento desta pesquisa de caráter experimental foi a escassez de dados sobre o comportamento de lajes armadas com barras ou telas soldadas de fabricação brasileira, submetidas a ações cíclicas. Outro motivo foi a carência de estudos a respeito da iteração prélaje x capa. Foi verificado que não houve ruptura nessa região da estrutura devido aos carregamentos cíclicos aplicados no meio do vão. Ficou evidenciado também que as soldas das telas afetam sua resistência à fadiga.Concrete bridge slabs, massive or pre-slabs, are structural elements susceptible to fatigue, due to loading applied to them. Pre-slabs, result of two different concretes, become even more susceptible to fatigue. This research presents the studies, tests and analysis of the results about the behavior of concrete bridge massive slabs or pre-slabs reinforced with steel bars and welded steel meshes due to fatigue loading. Axial testing in air of CA50 f10 mm in continuous bars and steel meshes were made in order to build the Wöhler Curve to the Brazilian conditions. Besides that, tests were made in 23 concrete slabs, 6 massive slabs and 17 preslabs, with several reinforcements arrangements, submitted to static and dynamic loading. The reinforcement configurations adopted in the slabs were based on the commonly used in these bridge elements in scale ½. One of main reasons that lead this experimental research development was the scarcity of data about the behavior of concrete slabs reinforced with rebars and welded mesh made in Brazil, submitted to cycle loading. Another reason was the lack of studies about the iteration between pre-slab and concrete cover. It was verified that no rupture was found in this region of the structure due to midspan cycle loading. The welding process caused loss of fatigue resistance.