Spelling suggestions: "subject:"4points"" "subject:"5points""
491 |
Ergodicidade e homeomorfismos anulares do toro / Ergodicity and annular homeomorphism of the torusRenato Belinelo Bortolatto 22 June 2012 (has links)
Seja f : T2 -> T2 um homeomorfismo homotópico a identidade e F : R2 -> R2 um levantamento de f tal que seu conjunto de rotação rho(F) é um segmento vertical não degenerado contido em 0 × R. Provamos que se f é ergódico com respeito a medida de Lebesgue no toro e se o vetor de rotação médio (com respeito a mesma medida) é da forma (0, alpha) para alpha em R\\Q então existe M > 0 tal que |(Fn (x) - x)1| <= M para todo x em R2 e n em Z (onde (.)1 :R2 -> R é definida por (x,y)1 =x). / Let f : T2 -> T2 be a homeomorphism homotopic to the identity and F : R2 -> R2 a lift of f such that the rotation set rho(F) is a non-degenerated vertical line segment contained in 0 × R. We prove that if f is ergodic with respect to the Lebesgue measure on the torus and the average rotation vector (with respect to same measure) is of the form (0, alpha) for alpha in R\\Q then there exists M > 0 such that |(Fn (x) - x)1| <= M for all x in R2 and n in Z (where (.)1 :R2 -> R is defined by (x, y)1 = x).
|
492 |
Caracterização e localização dos pontos notáveis do triângulo / Characterization and location of the notable points of the triangleElvis Donizeti Neves 01 February 2013 (has links)
O ensino de Matemática é, de modo geral, orientado pelos processos contidos nos livros didáticos. Sendo assim, a organização dos conceitos matemáticos nesses livros deveria ser capaz de permitir ao leitor interpretar a Matemática em sua essência, admitindo o estabelecimento de relações entre os conteúdos. No entanto, o que geralmente se observa nos materiais é um aglomerado de definições e conceitos desconexos que conduzem o leitor a dificuldades de aprendizado na área. Por essa razão, a presente dissertação teve o objetivo principal de localizar, além de caracterizar, os pontos notáveis do triângulo: o centróide ou baricentro (G), o ortocentro (H), o circuncentro (O), o centro (N) da circunferência de nove pontos, os três ex-centros das circunferências ex-inscritas, as projeções ortogonais dos vértices sobre os lados opostos e os pontos de tangência da circunferência inscrita e ex-inscrita. Quatro abordagens são apresentadas em busca de tal objetivo: a-) apresentar a geometria do triângulo segundo técnicas de percepção visual; b-) caracterizar alguns pontos notáveis do triângulo, como pontos de máximo ou de mínimo de funções com as demonstrações utilizando desigualdade de Cauchy-Schwarz e entre média aritmética e geométrica; c-) utilizar um sistema cartesiano adequado para o cálculo das abscissas e ordenadas do centróide (G), do ortocentro (H) e do circuncentro (O) de um triângulo; d-) utilizar os números complexos para a completa localização de todos os pontos notáveis do triângulo além de apresentar a equação da reta de Euler, o incentro (I) e os três excentros IA, IB e IC localizados em fórmulas simples. A dissertação finaliza com o Teorema de Feuerbach, apresentado com uma prova elementar, mostrando que a circunferência de nove pontos e a circunferência inscrita são tangentes internamente e que a circunferência dos nove pontos é tangente exteriormente a cada uma das três ex circunferências e o Teorema de Napoleão, no qual os baricentros de triângulos equiláteros, construídos a partir dos lados de um triângulo qualquer, formam um outro triângulo equilátero. Comparando as várias abordagens da dissertação, a conclusão é a de que a compreensão dos números complexos paradoxalmente simplifica a resolução de problemas de geometria plana e a solução de equações polinomiais. Assim, acredita-se que uma maior exploração desse conteúdo no ensino da Matemática poderia tornar o aprendizado mais atraente e simplificado / The teaching of Mathematics is generally guided by the procedures contained in the textbooks. Thus, the organization of the mathematical concepts in these books should be able to allow the reader to interpret the Mathematics in its essence, admitting the establishment of relationships between the contents. However, what is observed in the materials is a conglomeration of disparate definitions and concepts that lead the reader to learning difficulties in the area. For this reason, this work aimed to locate and characterize the notable points of the triangle: the centroid or barycenter (G), the orthocenter (H), the circumcenter (O), the center (N) of circumference of nine points, three former centers of the ex-inscribed circles, orthogonal projections of the vertices on the opposite sides and the points of tangency of the inscribed and the ex-inscribed circumference. Four approaches are presented to achieve these goals: a-) to introduce the geometry of the triangle using visual perception techniques, b-) to characterize some notable points of the triangle, as points of maximum or minimum of functions with the demonstrations using the Cauchy-Schwarz inequality and between the arithmetic and geometric mean;-c) to use a suitable Cartesian system for calculating the abscissas and ordinates of the centroid (G), of orthocenter (H) and of the circumcenter (O) of a triangle;-d) to use complex numbers for the complete location of all notable points of the triangle, beyond depicting the Euler equation of the line, the incenter (I) and the three former centers IA, IB and IC located in simple formulas. The work is concluded with the Feuerbach\'s Theorem, presented with an elementary proof, showing that the nine-point circle and the incircle is tangent internally and that the circumference of the nine points is externally tangent to each of the three ex-inscribed circles and the Napoleons Theorem, in which the barycenters of equilateral triangles, constructed from the sides of any triangle, form another equilateral triangle. Comparing the approaches detached hitherto, the conclusion is that the understanding of complex numbers paradoxically simplifies troubleshooting of plane geometry and the solution of polynomial equations. Thus, it is believed that further exploration of this content in mathematics education could make learning more attractive and simplified
|
493 |
Estudo biomecânico comparativo entre novo sistema de bloqueio (PAX) e sistema convencional de bloqueio (Synthes) em ensaios de arrancamento e teste de quatro pontos / Biomechanical study comparing new locking plate system (PAX) and conventional locking plate system (Synthes) in pullout and four points test.Renato Albuquerque de Oliveira Cavalcanti 20 January 2015 (has links)
Os materiais utilizados nas osteossínteses passam constantemente por avanços tecnológicos. Um dos mais recentes dispositivos é a chamada placa bloqueada, suas principais indicações são fraturas com alto grau de cominução, fraturas que não exigem uma redução anatômica, ossos osteopenicos, por exemplo, acometidos pela osteoporose, entre outras. Atualmente novos modelos de placas com bloqueio estão sendo desenvolvidos, onde a interface do parafuso e a placa são feito pela deformação do orifício, com a vantagem da instalação do parafuso em diversos ângulos. O presente projeto tem por objetivo estudar comparativamente a diferença entre os dois tipos de interface parafuso placa, como também realizar teste de quatro pontos comparando o sistema novo de bloqueio com o sistema convencional de bloqueio. Realizamos ensaios de arrancamento com sistema convencional de bloqueio (Synthes) e com o novo sistema de bloqueio (PAX) em parafusos 2,0mm; 2,4mm; 2,7mm e 3,5mm. Em todos os grupos testados o sistema convencional de bloqueio foi mais resistente e apresentou diferença significativa estatisticamente, teste de Mann- Witney (p< 0,05). Os valores de P obtidos foram: sistema 2.0mm p = 0,008; sistema 2.4 mm p= 0,008; sistema 2.7 mm p= 0,016; sistema 3.5 mm p= 0,008. No teste de 4 pontos utilizamos 20 placas da marca Synthes (sistema convencional de bloqueio) e 20 da marca PAX (novo sistema de bloqueio) e o sistema convencional de bloqueio se mostrou novamente mais resistente com diferença significativa. Os valores de P obtidos foram: sistema 2.0mm p = 0,008; sistema 2.4 mm p= 0,008; sistema 2.7 mm p= 0,008; sistema 3.5 mm p= 0,008. Conclui-se que o sistema convencional de bloqueio se mostrou mais resistente tanto no teste de arrancamento quanto no teste de flexão de quatro pontos. / The materials used in osteosynthesis constantly technological advances. One of the most recent devices is called the locking plate, its main indications are fractures with a high degree of comminution, fractures which do not require anatomical reduction, osteopenic bones, for example, affected by osteoporosis, among others. Currently new locking plate designs are being developed, where the screw interface and the plate are made by deformation of the hole, with the installation of the advantage screw at various angles. This study aims to compared the difference between the two types of interface screw - plate but also perform four-point test comparing the new locking system with the conventional system lock. Pullout tests conducted with conventional locking system (Synthes) and the new locking system (PAX) by screws 2.0mm; 2.4mm; 2.7mm and 3.5mm. In all groups tested the conventional system of blockade was stronger and showed a statistically significant difference, Mann-Witney test (p <0.05). P values were obtained: System 2.0mm P = 0.008; system 2.4 mm p = 0.008; System 2.7 mm p = 0.016; system 3.5 mm p = 0.008. In test points 4 used 20 Synthes plate mark (conventional blocking system) and 20 brand PAX (new locking system), the conventional locking system again showed a significant difference resistant. P values were obtained: System 2.0mm P = 0.008; system 2.4 mm p = 0.008; system 2.7 mm p = 0.008; system 3.5 mm p = 0.008. It follows that the conventional locking system has proved much more resistant peel test as in the four point bending test.
|
494 |
Variedades de Prym e semigrupos de Weierstrass / Prym varieties and Weierstrass semigroupCastilho, Tiago Nunes, 1983- 12 May 2013 (has links)
Orientador: Marcos Benevenuto Jardim / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Científica / Made available in DSpace on 2018-08-24T02:07:51Z (GMT). No. of bitstreams: 1
Castilho_TiagoNunes_D.pdf: 20018125 bytes, checksum: 181cd44948098969af37059c2215917a (MD5)
Previous issue date: 2013 / Resumo: Esta tese trata de variedades de Prym e de semigrupos de Weierstrass, ambos no contexto de recobrimentos duplos de curvas ramificados. A partir da descrição da variedade de Prym em termos de um conjunto de fibrações lineares do recobrimento, estuda-se a dualidade entre o lugar onde a aplicação de Gauss sobre o divisor Prym-Theta se degenera e o divisor de ramos do recobrimento duplo, em que provarse uma relação entre as fibras da aplicação de Gauss e os semigrupos de Weierstrass das ramificações do recobrimento / Abstract: ln this thesis we present results about Prym varieties and Weierstrass semigroups, both in the context of ramified double covers of curves. From the description of the Prym variety by a set of linear fibrations, we study the duality between the place where the Gauss map on the Prym-Theta divisor degenerates and the branch divisor of the double covering, in which we prove a relation between the fibers of the Gauss map and the Weierstrass semigroups of branched points of the double covering / Doutorado / Matematica / Doutor em Matemática
|
495 |
The feasibility of sand-abstraction as a viable method of ground water abstractionHussey, Stephen W. January 2003 (has links)
Many rural communities in arid areas of the world make extensive use of perennial water supplies retained within the sediment of a river channel. This naturally filtered water provides for their basic subsistence. A general term applied to the abstraction of water from river sediment is sand-abstraction. Ephemeral and seasonal rivers primarily drain the dryland regions of the world. These arid regions are typically subject to extensive environmental degradation with a consequent high degree of surface erosion. As a result, many of the rivers have become sand rivers, filled with copious amounts of sediment. Most arid areas are subject to occasional rainstorms and flash floods that immediately drain to waterways and saturate the sediment within the river channel. In larger rivers a perennial supply of water is maintained within the sediment. Despite a perceived potential for this water resource there has been little development of any small-scale technology that is suitable for use at a basic rural level. A research and study programme was instigated to assess fully, the potential of such a resource. Field research was undertaken to characterise typical sand rivers and to assess the water storage and water loss and retention factors within river sediment. A check list for identifying possible sand-abstraction sites was devised. In the process of this study the advantages of storing water in sand was fully appreciated and attention given to the development of initially less suitable sites in serious water deficit areas. Systems for efficient abstraction of water were reviewed and designs formulated for the fabrication of equipment to mechanically draw water from river sediment. A series of well-screens, well-points, infiltration galleries and caissons have been designed and initial tests have been conducted under field conditions. Simple technology handpumps that it was considered could be operated, maintained and repaired by rural communities using locally available materials have been developed in conjunction with the abstraction equipment. In consultation with rural people an analysis was made of the technical and sociological requirements that are considered essential for the sustainability of technology suitable for use by disadvantaged rural communities. Both practical and literature research has indicated the latent possibility of this technology. Interaction has been maintained with four communities throughout the research and development period and contributions and indications received are that there is a need to develop such a water source with an upgraded technology. The conclusion from the work undertaken is that development of the technology is worthwhile and that greater efforts should be made to promote it at a small-scale, rural level. In addition the potential to provide clean water in arid regions from such a lowtechnology application should be drawn to the attention of professional water engineers.
|
496 |
Ramification numbers and periodic points in arithmetic dynamical systemsNordqvist, Jonas January 2018 (has links)
The field of discrete dynamical systems is a rich and active field of research within mathematics, with applications ranging from biology to computer science, finance, engineering and various others. In this thesis properties of certain discrete dynamical systems are studied together with number theoretic properties of the functions defining these systems. The dynamical systems studied in this thesis are defined by iteration of power series g with a fixed point at the origin, tangent to the identity, and defined over fields of prime characteristic p. We are interested in the geometric location of the periodic points in the open unit disk. Recent results have shown that there is a connection between the lower ramification numbers of g and the geometric location of the periodic points in the open unit disk. The lower ramification numbers of g can be described as the multiplicity of zero as a fixed point of p-power iterates of g. Part of this thesis concerns characterizing power series having certain sequences of ramification numbers. The other part concerns utilizing these results in order to describe the geometric location of the periodic points in terms of their distance to the origin. More precisely, we characterize all 2-ramified power series, i.e. power series having ramification numbers of the form 2(1 + p + … + pn). Moreover, we also obtain a lower bound of the absolute value of the periodic points in the open unit disk of such series.
|
497 |
Complexité et changement climatique : une étude épistémologique des théories de la complexité transdisciplinaires et leur apport aux phénomènes socio-écologiques / Complexity and Climate Change? : an epistemological study of transdisciplinary complexity theories and their contribution to socio-ecological phenomenaWells, Jennifer 23 June 2009 (has links)
Cette thèse propose une analyse épistémologique des théories de la complexité, une évaluation de leur portée générale et de leur utilité dans des domaines particuliers, et la mise au jour de leur contribution décisive à la question centrale du changement climatique. L’objectif est de cerner la nature de la complexité à travers tout l’éventail des disciplines, car les théories de la complexité ne cessent de s’éteindre et la liste des bénéfices qu’on leur attribue de s’allonger. L’étude de cas du changement climatique est riche, y sont impliqués de nombreux systèmes complexes d’importance décisive pour le genre humain, parmi lesquels l’agriculture, l’énergie, l’eau et l’économie. Le présent travail propose d’abord une définition de la complexité généralisée, comprise comme cadre général de la pensée fondé sur six grandes catégories. Il procède ensuite à l’analyse à travers ce cadre, des dimensions scientifiques, politiques et éthiques du changement climatique. Notre point de départ est constitué par un examen attentif du trois corpus importants : le rapport du GEIC « Climate Change 2007, » « le Millennium Ecosystem Assessment, » et l’éthique du changement climatique. Il s’avère que la mise en œuvre des théories de la complexité est nécessaire pour mesurer de manière rigoureuse la portée non seulement des aspects multiples des différents systèmes complexes impliqués, mais aussi de l’ensemble dans toutes sa signification polyvalente. En s’interrogeant sur le rôle et l’utilité des théories de la complexité dans des domaines et à des échelles multiples, nous mettons en lumière une série de principes-clés sur la nature et l’usage de ces théories. / This dissertation presents an epistemological analysis of complexity theories, an evaluation of their contribution, both generally and to specific domains, and a demonstration of their important contribution to climate change. The objective is to provide a description of complexity theories across the whole range of disciplines, as complexity theories continue to expand and the list of their proposed benefits continue to grow. The case study of climate change is rich, as it touches on a number of complex systems of primary significance to humanity, such as agriculture, energy, water, and the economy. The present work proposes first a definition of generalized complexity, comprised of a general framework of the field based upon six major categories. It proceeds to analyze, in light of this framework, the scientific, ethical and political dimensions of climate change. Our point of departure consists in a thorough examination of three important bodies of literature: the IPCC report “Climate Change 2007,” the “Millennium Ecosystem Assessment,” and the ethics of climate change. The dissertation shows that the use of complexity theories is necessary in order to measure in a rigorous manner the contribution, not only of the multiple aspects of different complex systems involved, but also of the framework as an ensemble, with its polyvalent signification. By examining the role and the utility of complexity theories in multiple fields at multiple scales, we reveal a series of key principles regarding the nature and usage of these theories.
|
498 |
Cued Click-Point MemorabilitySvensson, Rickard January 2015 (has links)
The Safety of passwords has been in question for over 40 years, long before the Internet. While improvements have been made to ensure security nothing has changed with passwords since the emergence of the Internet. Passwords need to be long and complex to be secure and users should not reuse their passwords. In a world where there are thousands of services on the internet requiring authentication to keep passwords safe users will have to remember a lot of passwords. Studies show however that users are prone to both create bad passwords but to also reuse their passwords on different sites. A lot of different alternatives to passwords has been proposed but none has become dominant. Is there a good alternative to text-based passwords? Can a graphical password be that alternative? The purpose of this thesis is to create a prototype of a CCP-like system and to conduct a memorability and usability test with it. The test results suggest that CCP is easy to use for users new to the concept of graphical passwords. A CCP-password also seems memorable with most participants recalling their passwords after a week with ease. PCCP can be a good substitute for passwords since it is easy to use, easy to remember and potentially more secure than text-based passwords.
|
499 |
Cultivating a Food Movement : Slow Food USA’s Role in Moving Society Towards SustainabilityFeldman, Maja, Kingfisher, Alli, Sundborg, Cindy January 2011 (has links)
With society’s growing population and the earth’s limited resources, the current world food system is unsustainable. Slow Food USA (SFUSA) is an existing food-related Non-Governmental Organization (NGO) focusing on the expansion of Good, Clean, and Fair food. This research aims to help SFUSA to strategically support society’s move towards sustainability. To do this, the authors used the Framework for Strategic Sustainable Development (FSSD) to examine the current reality of SFUSA, where the opportunities and challenges for the organization to strategically plan toward sustainability were identified. The authors then used Leverage Points (LPs) to identify opportunities for how SFUSA can strategically intervene in the world food system to create change and the challenges that exist in doing so. The results of this research allowed the team to create a list of recommendations. Of these results, five were picked as the most strategic recommendations for SFUSA: 1) Co-create a shared common vision of sustainable food for society 2) Define a common language and branding among chapters that are in alignment with SFUSA 3) Implement a strategic planning process founded in a principle-based definition of sustainability 4) Expand educational outreach to specific targeted groups at the chapter level 5) Advocate for policy changes to remove barriers to widely available and affordable, sustainably produced agriculture.
|
500 |
Développement de films de polycaprolactone biomimétiques favorisant la différenciation ostéoblastique de cellules souchesJann, Jessica January 2018 (has links)
Le développement d’un biomatériau contrôlant précisément le comportement de cellules souches serait un avantage considérable pour des applications de médecine régénératrice et d’ingénierie tissulaire. Actuellement, le vieillissement de la population mondiale est associé à de nombreux problèmes de dégénérescence des tissus, en particulier dans le contexte osseux. Le coût annuel des opérations chirurgicales orthopédiques pratiquées aux États-Unis s’élève à 8.2 milliards de dollars US. Afin de trouver des alternatives aux greffes traditionnelles, des biomatériaux mimant la physiologie osseuse ont été conçus. Une des stratégies consiste à préparer des matériaux biomimétiques en fonctionnalisant, par exemple, la surface des matériaux par des peptides dérivés des protéines d’adhésion de la matrice extracellulaire (ECM) tel que la fibronectine pour favoriser l’ancrage des cellules osseuses. D’autres molécules comme les protéines morphogénétiques osseuses (BMPs) jouent un rôle essentiel dans le processus physiologique de la réparation osseuse. Ces BMPs peuvent être combinées aux biomatériaux afin d’orienter la réponse des cellules osseuses et ainsi améliorer la régénération des tissus. L’utilisation de peptides dérivés des BMPs, 300 fois moins dispendieux, ajoute un avantage considérable dans le développement des matériaux biomimétiques. En outre, des relations croisées entre les récepteurs cellulaires des protéines de l’ECM et ceux des BMPs peuvent influencer la signalisation et la différenciation des cellules osseuses, d’où l’intérêt de fonctionnaliser les biomatériaux non seulement avec des molécules d’adhésion, mais aussi avec des BMPs ou leurs peptides dérivés.
Dans ce projet, un biomatériau biomimétique de 3eme génération a été développé afin de permettre l’adhésion et l’orientation des cellules souches vers la lignée ostéoblastique. L’étude a consisté à analyser le potentiel de la co-immobilisation d’un peptide d’adhésion dérivé de la fibronectine (pFibro) et d’un peptide dérivé de la BMP-9 (SpBMP-9) sur un film de polycaprolactone (PCL). L’utilisation d’un peptide négatif du SpBMP-9, le NSpBMP-9, a permis de vérifier les effets synergiques potentiels de cette co-immobilisation. Dans un premier temps, l’attachement et l’organisation du cytosquelette des cellules ont été déterminés par un immunomarquage des protéines du cytosquelette. Puis la cinétique d’activation de la voie de signalisation Smad impliquée dans la différenciation ostéoblastique a été analysée par immunobuvardage de type Western. Afin de vérifier la différenciation des cellules souches vers un phénotype défini, l’expression de gènes codant pour des marqueurs de différenciation ostéogénique (Runx2, Ostérix), chondrogénique (Sox9) et adipogénique (PPARγ) a également été évaluée par des immunobuvardages de type Western.
Ce projet de recherche a amélioré les connaissances actuelles sur les interactions entre les biomatériaux co-fonctionnalisés par des peptides d’adhésion et dérivés de la BMP-9 et les cellules osseuses, afin de potentialiser les propriétés ontéoconductive, ostéointégrative et ostéoinductive essentielles pour obtenir un matériau biomimétique efficace.
|
Page generated in 0.025 seconds