868 resultados para post-buckling analysis


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The aim of this study was to analyze the alterations of arm and leg movements of patients during stroke gait. Joint angles of upper and lower limbs and spatiotemporal variables were evaluated in two groups: hemiparetic group (HG, 14 hemiparetic men, 53 ± 10 years) and control group (CG, 7 able-bodied men, 50 ± 4 years). The statistical analysis was based on the following comparisons (P ≤ 0.05): 1) right versus left sides of CG; 2) affected (AF) versus unaffected (UF) sides of HG; 3) CG versus both the affected and unaffected sides of HG, and 4) an intracycle comparison of the kinematic continuous angular variables between HG and CG. This study showed that the affected upper limb motion in stroke gait was characterized by a decreased range of motion of the glenohumeral (HG: 6.3 ± 4.5, CG: 20.1 ± 8.2) and elbow joints (AF: 8.4 ± 4.4, UF: 15.6 ± 7.6) on the sagittal plane and elbow joint flexion throughout the cycle (AF: 68.2 ± 0.4, CG: 46.8 ± 2.7). The glenohumeral joint presented a higher abduction angle (AF: 14.2 ± 1.6, CG: 11.5 ± 4.0) and a lower external rotation throughout the cycle (AF: 4.6 ± 1.2, CG: 22.0 ± 3.0). The lower limbs showed typical alterations of the stroke gait patterns. Thus, the changes in upper and lower limb motion of stroke gait were identified. The description of upper limb motion in stroke gait is new and complements gait analysis.

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Introduction: Pre-implantation kidney biopsy is a decision-making tool when considering the use of grafts from deceased donors with expanded criteria, implanting one or two kidneys and comparing this to post-transplantation biopsies. The role of histopathological alterations in kidney compartments as a prognostic factor in graft survival and function has had conflicting results. Objective: This study evaluated the prevalence of chronic alterations in pre-implant biopsies of kidney grafts and the association of findings with graft function and survival in one year post-transplant. Methods: 110 biopsies were analyzed between 2006 and 2009 at Santa Casa de Porto Alegre, including live donors, ideal deceased donors and those with expanded criteria. The score was computed according to criteria suggested by Remuzzi. The glomerular filtration rate (GFR) was calculated using the abbreviated MDRD formula. Results: No statistical difference was found in the survival of donors stratified according to Remuzzi criteria. The GFR was significantly associated with the total scores in the groups with mild and moderate alterations, and in the kidney compartments alone, by univariate analysis. The multivariate model found an association with the presence of arteriosclerosis, glomerulosclerosis, acute rejection and delayed graft function. Conclusion: Pre-transplant chronic kidney alterations did not influence the post-transplantation one-year graft survival, but arteriosclerosis and glomerulosclerosis is predictive of a worse GFR. Delayed graft function and acute rejection are independent prognostic factors.

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ABSTRACT The present study aims to evaluate crop, pasture and forest land prices in Brazil, between 1994 and 2010, in the light of Post-Keynesian theory. The results provide evidence that land, more than just a simple factor of production, must be conceived of as an economic asset. In fact, the price of rural land is determined not only by the expected profitability deriving from agricultural activities but also by the agents' expectations about its future appreciation and liquidity in an economic environment permeated with uncertainty. In this context, as an object of speculation, land has been particularly important as a store of value.

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Avec l’échec des négociations entre les États-Unis et la Corée du Nord, menées depuis le début des années 1990, sur la question du nucléaire, le problème est devenu graduellement l’affaire des pays voisins, tous soucieux de l’avenir de la région du sud-est asiatique. Présentée comme le seul allié de la Corée du Nord, la China a été invitée à participer à des négociations à trois, à quatre (1997-1998), et à six (2003-2007), dans l’espoir de faire entendre raison au régime isolé, mais jusqu’à maintenant, aucune des tentatives n’est parvenue à satisfaire chacun des membres à la table. Alors que la tension monte et que la politique américaine se fait de moins en moins flexible, la Chine quant à elle, continue d’encourager le retour des négociations à six (Six-Party Talks) dans l’optique de dénucléariser la péninsule coréenne, tout en travaillant à maintenir ses liens avec la Corée du Nord. Le fil conducteur de cette présente recherche est d’abord d’essayer de comprendre pourquoi la Chine continue de soutenir la Corée du Nord, fournissant dons alimentaires et financiers. L’idée est donc d’analyser, selon les principes du réalisme néoclassique, la politique étrangère de la Chine. L’hypothèse principale de cette théorie renvoie à l’idée que la distribution du pouvoir dans le système international influence la politique étrangère des États, mais que des variables au niveau de l’état et/ou de l’individu interviennent dans la formulation et l’application de celle-ci. Il est proposé ici que le lien entre l’unipolarité du système international et la politique nord-coréenne de la Chine, est façonné par des variables intermédiaires telles que : a) la perception des leaders de la distribution du pouvoir et de leur place dans le système international; b) l’idéologie du régime politique, et; c) le type d’unité responsable de la prise de décision en politique étrangère. L’analyse de chacune des variables permettra de faire la lumière sur les intérêts politiques et économiques de la Chine dans l’entretien de cette relation avec la Corée du Nord.

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Les histones sont des protéines nucléaires hautement conservées chez les cellules des eucaryotes. Elles permettent d’organiser et de compacter l’ADN sous la forme de nucléosomes, ceux-ci representant les sous unités de base de la chromatine. Les histones peuvent être modifiées par de nombreuses modifications post-traductionnelles (PTMs) telles que l’acétylation, la méthylation et la phosphorylation. Ces modifications jouent un rôle essentiel dans la réplication de l’ADN, la transcription et l’assemblage de la chromatine. L’abondance de ces modifications peut varier de facon significative lors du developpement des maladies incluant plusieurs types de cancer. Par exemple, la perte totale de la triméthylation sur H4K20 ainsi que l’acétylation sur H4K16 sont des marqueurs tumoraux spécifiques a certains types de cancer chez l’humain. Par conséquent, l’étude de ces modifications et des événements determinant la dynamique des leurs changements d’abondance sont des atouts importants pour mieux comprendre les fonctions cellulaires et moléculaires lors du développement de la maladie. De manière générale, les modifications des histones sont étudiées par des approches biochimiques telles que les immuno-buvardage de type Western ou les méthodes d’immunoprécipitation de la chromatine (ChIP). Cependant, ces approches présentent plusieurs inconvénients telles que le manque de spécificité ou la disponibilité des anticorps, leur coût ou encore la difficulté de les produire et de les valider. Au cours des dernières décennies, la spectrométrie de masse (MS) s’est avérée être une méthode performante pour la caractérisation et la quantification des modifications d’histones. La MS offre de nombreux avantages par rapport aux techniques traditionnelles. Entre autre, elle permet d’effectuer des analyses reproductibles, spécifiques et facilite l’etude d’un large spectre de PTMs en une seule analyse. Dans cette thèse, nous présenterons le développement et l’application de nouveaux outils analytiques pour l’identification et à la quantification des PTMs modifiant les histones. Dans un premier temps, une méthode a été développée pour mesurer les changements d’acétylation spécifiques à certains sites des histones. Cette méthode combine l’analyse des histones intactes et les méthodes de séquençage peptidique afin de déterminer les changements d’acétylation suite à la réaction in vitro par l’histone acétyltransférase (HAT) de levure Rtt109 en présence de ses chaperonnes (Asf1 ou Vps75). Dans un second temps, nous avons développé une méthode d’analyse des peptides isomériques des histones. Cette méthode combine la LC-MS/MS à haute résolution et un nouvel outil informatique appelé Iso-PeptidAce qui permet de déconvoluer les spectres mixtes de peptides isomériques. Nous avons évalué Iso-PeptidAce avec un mélange de peptides synthétiques isomériques. Nous avons également validé les performances de cette approche avec des histones isolées de cellules humaines érythroleucémiques (K562) traitées avec des inhibiteurs d’histones désacétylases (HDACi) utilisés en clinique, et des histones de Saccharomyces cerevisiae liées au facteur d’assemblage de la chromatine (CAF-1) purifiées par chromatographie d’affinité. Enfin, en utilisant la méthode présentée précédemment, nous avons fait une analyse approfondie de la spécificité de plusieurs HATs et HDACs chez Schizosaccharomyces pombe. Nous avons donc déterminé les niveaux d’acétylation d’histones purifiées à partir de cellules contrôles ou de souches mutantes auxquelles il manque une HAT ou HDAC. Notre analyse nous a permis de valider plusieurs cibles connues des HATs et HDACs et d’en identifier de nouvelles. Nos données ont également permis de définir le rôle des différentes HATs et HDACs dans le maintien de l’équilibre d’acétylation des histones. Dans l’ensemble, nous anticipons que les méthodes décrites dans cette thèse permettront de résoudre certains défis rencontrés dans l’étude de la chromatine. De plus, ces données apportent de nouvelles connaissances pour l’élaboration d’études génétiques et biochimiques utilisant S. pombe.

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The following paper is a critical theorist analysis of post-structuralist philosophy. It examines the omission of an economic critique in post-structuralism and describes this omission as the result of a particular flaw in Nietzsche's epistemological work, an error which has persisted all the way down through deconstruction, post-colonialism, and cultural studies. The paper seeks to reintroduce an economic critique of capitalism back into the social critique of post-structuralism, with the promise that the combination of the two will prove stronger than either critical theory or post-structuralism alone. To achieve this it reinterprets Marx' concept of metabolism as a critical economic category that mirrors post-structuralism's concept of differance.

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The issue of levels of participation in post-compulsory education has been emphasised by the current policy initiatives to increase the age to which some form of participation is compulsory. One of the acknowledged weaknesses of research in the field of children's intentions with regard to participation is the lack of longitudinal data. This paper offers a longitudinal analysis using the Youth Survey from the British Household Panel Survey. The results show that most children can express intentions with regard to future participation very early in their secondary school careers and that these intentions are good predictors of actual behaviour five years later. Intentions to stay on are more consistent than intentions to leave and most children who finally leave at 16 have at some point said they want to remain in education post-16. The strongest association with participation levels is attainment at GCSE. However, there are also influences of gender and parental background and these remain, even after attainment is held constant. The results show the value of focusing on intentions for participation at a very early stage of children's school careers and also the importance of current attempts to reform curriculum and assessment for the 14-19 age group.

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Wave solutions to a mechanochemical model for cytoskeletal activity are studied and the results applied to the waves of chemical and mechanical activity that sweep over an egg shortly after fertilization. The model takes into account the calcium-controlled presence of actively contractile units in the cytoplasm, and consists of a viscoelastic force equilibrium equation and a conservation equation for calcium. Using piecewise linear caricatures, we obtain analytic solutions for travelling waves on a strip and demonstrate uiat the full nonlinear system behaves as predicted by the analytic solutions. The equations are solved on a sphere and the numerical results are similar to the analytic solutions. We indicate how the speed of the waves can be used as a diagnostic tool with which the chemical reactivity of the egg surface can be measured.

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A detailed study was performed for a sample of low-mass pre-main-sequence (PMS) stars, previously identified as weak-line T Tauri stars, which are compared to members of the Tucanae and Horologium Associations. Aiming to verify if there is any pattern of abundances when comparing the young stars at different phases, we selected objects in the range from 1 to 100 Myr, which covers most of PMS evolution. High-resolution optical spectra were acquired at European Southern Observatory and Observatorio do Pico dos Dias. The stellar fundamental parameters effective temperature and gravity were calculated by excitation and ionization equilibria of iron absorption lines. Chemical abundances were obtained via equivalent width calculations and spectral synthesis for 44 per cent of the sample, which shows metallicities within 0.5 dex solar. A classification was developed based on equivalent width of Li I 6708 angstrom and Ha lines and spectral types of the studied stars. This classification allowed a separation of the sample into categories that correspond to different evolutive stages in the PMS. The position of these stars in the Hertzsprung-Russell diagram was also inspected in order to estimate their ages and masses. Among the studied objects, it was verified that our sample actually contains seven weak-line T Tauri stars, three are Classical T Tauri, 12 are Fe/Ge PMS stars and 21 are post-T Tauri or young main-sequence stars. An estimation of circumstellar luminosity was obtained using a disc model to reproduce the observed spectral energy distribution. Most of the stars show low levels of circumstellar emission, corresponding to less than 30 per cent of the total emission.

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Background: Studies evaluating acceptability of simplified follow-up after medical abortion have focused on high-resource or urban settings where telephones, road connections, and modes of transport are available and where women have formal education. Objective: To investigate women's acceptability of home-assessment of abortion and whether acceptability of medical abortion differs by in-clinic or home-assessment of abortion outcome in a low-resource setting in India. Design: Secondary outcome of a randomised, controlled, non-inferiority trial. Setting Outpatient primary health care clinics in rural and urban Rajasthan, India. Population: Women were eligible if they sought abortion with a gestation up to 9 weeks, lived within defined study area and agreed to follow-up. Women were ineligible if they had known contraindications to medical abortion, haemoglobin < 85mg/l and were below 18 years. Methods: Abortion outcome assessment through routine clinic follow-up by a doctor was compared with home-assessment using a low-sensitivity pregnancy test and a pictorial instruction sheet. A computerized random number generator generated the randomisation sequence (1: 1) in blocks of six. Research assistants randomly allocated eligible women who opted for medical abortion (mifepristone and misoprostol), using opaque sealed envelopes. Blinding during outcome assessment was not possible. Main outcome measures: Women's acceptability of home-assessment was measured as future preference of follow-up. Overall satisfaction, expectations, and comparison with previous abortion experiences were compared between study groups. Results: 731 women were randomized to the clinic follow-up group (n = 353) or home-assessment group (n = 378). 623 (85%) women were successfully followed up, of those 597 (96%) were satisfied and 592 (95%) found the abortion better or as expected, with no difference between study groups. The majority, 355 (57%) women, preferred home-assessment in the event of a future abortion. Significantly more women, 284 (82%), in the home-assessment group preferred home-assessment in the future, as compared with 188 (70%) of women in the clinic follow-up group, who preferred clinic follow-up in the future (p < 0.001). Conclusion: Home-assessment is highly acceptable among women in low-resource, and rural, settings. The choice to follow-up an early medical abortion according to women's preference should be offered to foster women's reproductive autonomy.

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This analysis aimed to identify characteristics of accidents that would, probably, provoke rabies infection. A total of 14,409 survey questionnaires for surveillance of human rabies from the Brazilian Information System for Disease Notification (SINAN), from 2000 to 2005, were analyzed. Regarding demographics, it was observed that 7,377 (51.5%) of the victims were white, 4,458 (30.93%) were children and 8,008 (55.58%) were males. Urban cases were prevalent (88.10%) while dogs were the animals most frequently involved in accidents, in 11,700 cases (81.19%). Bites (84.35%) and scratches (19.15%) were the most prevalent exposure types, and occurred predominantly on victims' extremities (38.79%). The prophylactic measure taken in 6,179 cases comprised anti-rabies vaccine; of these victims, 421 (2.92%) showed systemic reactions while 693 (4.80%) reported no response. The importance of developing awareness in professionals that should correctly report post-exposure immunoprophylaxis cases is emphasized given the high number of individuals who receive this type of treatment annually.

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Objectives: The objective of the present study was to evaluate a prefabricated intraradicular threaded pure titanium post, designed and developed at the Sao Jose dos Campos School of Dentistry - UNESP, Brazil. This new post was designed to minimize stresses observed with prefabricated post systems and to improve cost-benefits. Materials and and methods: Fracture resistance testing of the post/core/root complex, fracture analysis by microscopy and stress analysis by the finite element method were used for post evaluation. The following four prefabricated metal post systems were analyzed: group 1, experimental post; group 2, modification of the experimental post; group 3, Flexi Post, and group 4, Para Post. For the analysis of fracture resistance, 40 bovine teeth were randomly assigned to the four groups (n=10) and used for the fabrication of test specimens simulating the situation in the mouth. The test specimens were subjected to compressive strength testing until fracture in an EMIC universal testing machine. After fracture of the test specimens, their roots were sectioned and analyzed by microscopy. For the finite element method, specimens of the fracture resistance test were simulated by computer modeling to determine the stress distribution pattern in the post systems studied. Results: The fracture test presented the following averages and standard deviation: G1 (45.63 +/- 8.77), G2 (49.98 +/- 7.08), G3 (43.84 +/- 5.52), G4 (47.61 +/- 7.23). Stress was homogenously distributed along the body of the intraradicular post in group 1, whereas high stress concentrations in certain regions were observed in the other groups. These stress concentrations in the body of the post induced the same stress concentration in root dentin. Conclusions: The experimental post (original and modified versions) presented similar fracture resistance and better results in the stress analysis when compared with the commercial post systems tested (08/2008PA/CEP).