Das Ziel der vorliegenden Arbeit war es, den klinischen Nutzen der Sonographie und der Magnetresonanztomographie bei intraokulären und orbitalen Erkrankungen bei Hunden und Katzen einzuschätzen und die diagnostische Wertigkeit der bildgebenden Verfahren zu analysieren. Weiterhin wurden charakteristische Befunde einzelner intraokulärer und retrobulbärer Erkrankungen in den bildgebenden Verfahren dargestellt. Die nach der Bildgebung gestellte Diagnose konnte in 67,2% der Fälle durch eine zytologische Untersuchung bestätigt werden. In den restlichen 19,7% der Fälle fand die Diagnose durch die Bildgebung im Zusammenhang mit der Anamnese, Symptomatologie und Therapie statt.

[pt] Espaços de moduli de polígonos em R(3) com comprimento dos lados fixados é um exemplo amplamente estudado de variedade simplética. Esses espaços podem ser descritos como quociente simplético de um número finito de órbitas coadjuntas pelo grupo SU(2). Nesta tese esses espaços de moduli são identificados como folhas simpléticas de uma variedade de Poisson que pode ser construída como quociente. Essa construção é a seguir generalizada ao caso de um produto de um número finito de órbitas coadjuntas pelo grupo SU(n), e o resultado principal desse trabalho de tese descreve como esses espaços de moduli de polígonos generalizados formam uma folheação em folhas simpléticas de uma variedade de Poisson. / [en] Moduli spaces of polygons in R(3)with fixed sides length are a widely studied example of symplectic manifold that can be described as the symplectic quotient of a finite number of SU(2)−coadjoint orbits by the diagonal action of the group SU(2). In this thesis these spaces are identified as the symplectic leaves of a Poisson manifold, that can itself be obtained by a quotient procedure. The construction is then generalized to the case of the quotient of a product of finitely many SU(n)−coadjoint orbits by the diagonal action of SU(n), and the main result of this thesis describes how these moduli spaces of generalized polygons fit together as the symplectic leaves of a quotient Poisson manifold.

[pt] Este trabalho está relacionado ao problema do uso eficiente da órbita de satélite geoestacionário. A utilização eficiente da órbita é obtida através de um algoritmo de otimização que permite escolher as posições orbitais para os diversos sistemas de modo a reduzir ao máximo o percentual do arco orbital utilizado. Sendo assim, desenvolvido um modelo matemático que considerou além de aspectos de interferência, detalhes da geometria envolvida no problema (posições orbitais dos satélites, posições das estações terrenas, apontamento de antenas, etc.). Este modelo foi utilizado na definição de um problema de otimização com restrição cuja função objetivo se baseia na parcela do arco orbital utilizado. Neste problema de otimização com restrição foram consideradas restrições de níveis máximos de interferência (de entrada única e agregada) além de restrições de arcos orbitais, impostas por aspecto de propagação. O algoritmo de otimização utilizado requer o cálculo do Vetor Gradiente e da Matriz Hessiana. Para evitar erros de origem numéricos essas quantidades foram calculadas utilizando expressões analíticas desenvolvidas neste trabalho. O método matemático foi aplicado a situações específicas conduzindo a resultados que mostraram um uso eficiente da órbita de satélites geoestacionários através de soluções onde a parcela utilizada do arco é minimizada. / [en] This work is related to the efficient use of the geostationary satellite orbit. It presents and describes an optimization model which chooses the best orbital position for each satellite so that the length used orbital arc is minimized. A mathematical model considering aspects such as interference, geometry details (orbital position of the systems, earth station position, boresight of the antenna, etc) is proposed. This model was used in the definition of a constrained optimization problem in which the cost function is the length of the used orbital arc. Constrained imposed by propagation aspects (minimum elevation angle) and by the maximum allowable interference levels (aggregate and single-entry) are considered. The optimization algorithm requires the evaluation of the Gradient vector and the Hessian matrix. To avoid numeric problems, analytic expressions of these quantities were derived. Results of the application of this model to specific situations involving real data were also described and conducted to solutions where the length of the orbit used was minimized

Einen Orbitadefekt mit Verlust des Auges und der filigranen Lidstrukturen kann eine implantatverankerte Silikonepithese im Halt sicher und bei geöffnetem Auge ästhetisch mit gutem Ergebnis abdecken. Bei Lidschluß fällt allerdings die Starrheit der Lider in der Epithese auf. Ziel der Entwicklung war es, das künstliche Oberlid in der Orbitaepithese beweglich zu gestalten und so durch die gewonnene Dynamik ein natürlicheres Aussehen beim Patienten zu erreichen. In der Epithese sollten alle Komponenten integriert sein, um das künstliche Oberlid synchron zum gesunden Auge zu bewegen. Als bewegliches Oberlid erwies sich gegossene Latexmilch als Material am geeignetsten. Dieses Material war elastisch, einfärbbar und konnte den Belastungen der ungefähr 30 unwillkürlichen Lidschlagbewegungen pro Minute standhalten. Das künstliche Oberlid wurde analog dem natürlichen Vorbild des Lidöffners nach dem Prinzip der Zuggurtung über die Augenprothese nach oben hinten gezogen. Als Antrieb wurde ein DC-Mikromotor eingesetzt, der das Oberlid mit Hilfe eines kleinen Polyamidfadens, welcher an der inneren verstärkten Lidkante befestigt war, nach kranial bewegte. Der Faden wurde über eine Kanülenführung auf eine Seilrolle gewickelt. Nachdem sich ein aufgebautes Tischmodell im Test bewährt hatte, wurde eine einbaufähige elektronische Schaltung in SMD-(Surface Mounted Device) Technik entwickelt, die einerseits den Antrieb steuerte und andererseits die zur Synchronisation erforderlichen Muskelpotentiale verarbeitete. Diese zwei doppelseitig bestückten Platinen wurden direkt hinter die individuell aus Glas vom Okularisten hergestellte Augenprothese positioniert. Über fünf integrierte einstellbare Potentiometer konnten die abgeleiteten Muskelsignale für eine verzögerungsfreie Lidbewegnung beim Patienten individuell verändert werden. Die Energiebereitstellung für die Elektronik und den Motor konnte aufgrund der zu niedrigen Nennkapazitäten nicht durch Akkumulatoren erfolgen, sondern wurde durch eine kleine leicht auswechselbare Batterie erreicht, die hochgerechnet Strom für 7 bis 14 Tage lieferte. Da die einzelnen Komponenten nicht frei in der Epithese liegen konnten, wurde als Schutz ein Gehäuse in hartem Acrylatkunststoff konzipiert. Da die Anordnung der Batterie unter oder hinter dem Motor möglich war und auch die Elektronik versetzt zu Batterie und Motor angebracht werden konnte, konnte so die Geometrie des Gehäuses in Grenzen dem individuellen Orbitadefekt angepaßt werden. In klinischen Versuchen an gesunden Probanden und Patienten mit implantatverankerten Orbitaepithesen zeigte sich, daß Muskelpotentiale vom M. orbicularis oculi aus dem gesunden Oberlid oder teilweise der exenterierten Orbita mit Restaktivität des Lidschließers mit Nadelelektroden bipolar abgeleitet zur Ansteuerung des Motors geeignet waren. Mit diesen Biopotentialen wurde das reibungslose Funktionieren der synchronen Lidbewegung des Prototypen an einer freiwilligen gesunden Versuchsperson getestet. Nach umfangreichen Labortestungen wurden zwei Patienten mit dieser neuartigen Orbitaepithese rehabilitiert. Bei den Patienten wurde das passende Gehäuse mit den gekapselten Funktionseinheiten individuell hergestellt und dieses in eine Silikonepithese eingearbeitet. Gehalten wurde die Silikonepithese über implantatfixierte Magnetabutments. Die Muskelpotentialableitung zur Triggerung der synchronen Lidbewegung erfolgte durch eine intramuskuläre EMG - Ableitung des M. orbicularis oculi. Beim ersten Patienten gelang dieses über eine sterile Nadelelektrode, die allerdings beim Tragen der neuen Orbitaepithese jedes Mal neu in den Muskel eingestochen werden mußte. Beim zweiten Patienten wurden die Muskelpotentiale über eine subcutan implantierte dünne EMG - Elektrode aufgenommen. Die Myosignale wurden bei beiden Patienten bipolar abgeleitet. Die zweite differente Elektrode kontaktierte einen implantatfixierten Magneten. Die Neutralelektrode war mit einem weiteren implantatverankerten Magneten verbunden. Die abgeleiteten Muskelimpulse beim Lidschlag konnten so bei den Patienten eine zum gesunden Oberlid synchrone künstliche Lidbewegung initiieren. Da die Bauteile zur künstlichen Lidbewegung noch nicht beliebig klein zu gestalten sind, können zur Zeit noch nicht alle Orbitaepithesenträger mit der neuartigen Epithese rehabilitiert werden. Um bei Patienten mit kleineren Orbitadefekten die Epithese eingliedern zu können, muß sich die zukünftige Forschung auf eine noch weitere Größenreduktion der einzelnen Komponenten konzentrieren. Durch die Entwicklung von telemetrischen Verfahren wird es möglich sein, die von einer intramuskuären implantierten, für diese Anwendung optimierten EMG - Elektrode emfangenen Signale ohne infektionsgefährdete Hautdurchleitung zur Epithese zu übertragen. / An orbit defect with loss of the eye and its delicate lid structures can be concealed with an implant anchored silicon facial prosthesis. This method assures secure retention and good esthetic results as long as the eye remains open. However, when the healthy lid closes, the immobility of the prosthesis becomes conspicuous. The aim of this development was to animate the artificial lid in the orbita prosthesis to give the patient a much more natural appearance. All components in the prosthesis were integrated to create an artificial lid that would blink in synchrony with that of the healthy eye. The material which proved to be most suited for the moveable eyelid was cast latex milk. It was elastic, would take dyes and was robust enough to withstand approximately 30 involuntary lid movements per minute. The artificial upper lid was pulled up behind the eye prosthesis by means of a fine thread, analogous to the natural lid opener. This is driven by a DC micromotor which lifts the upper lid in a cranial direction with a polyamid thread attached to the reinforced rim of the lid. The thread was wound onto a minute pulley. After a successful model had been constructed, an electronic circuit was developed in SMD (Surface Mounted Device) technique which drove the motor and processed the muscle potential necessary for the synchronization. These two double-sided circuit boards were positioned directly behind the artificial eye, which had been created specially by an ophthalmologist. By means of five integrated potentiometers, the muscle signals picked up were individually modified and adjusted to eliminate any delays in the lid movement. The low nominal capacity provided by accumulators ruled them out as a possible power supply for the electronics and motor, and instead, a small, light replaceable battery, capable of powering the motor for 7 to 14 days, was chosen. The individual components were then assembled and housed in a case of rigid acrylate plastic. It was possible to position the battery either under or behind the motor and to and stagger the electronics parts to the position of the battery and motor. This enhanced the adaptability of the case's geometric form to the individual orbit defect. Clinical tests with healthy test persons and patients with implant-anchored orbital prostheses demonstrated that muscle potentials from the orbicularis oculi muscle could be picked up from the healthy upper lid with bipolar needle electrodes. This was also possible in some cases when after exenteration the orbicularis oculi muscle remained partially active and continued to emit muscle potentials. With these biopotentials, the synchronic lid movement of the prototype was tested on a voluntary healthy test person. It functioned flawlessly. After extensive laboratory tests, two patients were rehabilitated with the new orbita prosthesis. For each patient a case for the components was designed and fitted into a silicone prosthesis retained with implant-anchored magnet abutments. The muscle potentials were conducted by an intramuscular electromyography (EMG) to trigger synchronous lid movement. With the first patient, a sterile needle electrode was used, but this had to be reinserted into the muscle each time the prosthesis was fitted. In the second patient the muscle potentials were picked up via a thin EMG-electrode implanted subcutaneously. In both cases bipolar conduction was taken. The second different electrode was attached to one implant-anchored magnet; the neutral electrode to another. In both patients, the muscle impulses emitted during lid closure initiated an artificial lid movement in synchrony with the healthy eyelid. Since the component parts cannot be reduced beyond a certain minimum size, not all orbit prosthesis wearers can be rehabilitated with the new prosthesis. In order to fit patients with smaller defects, future research will have to concentrate on a further reduction in component size. With further developments in telemetric procedures it will become possible to transmit signals received from a EMG electrode implanted in the muscle to the prosthesis without the dangers of infection inherent in conducting them through the skin.

[pt] Temos como objetivo principal classificar, a menos de semi-conjugação, os grupos de homeomorfismos crescentes da reta, com no máximo N pontos fixos. Começando pelos casos já classificados, N igual a 0 pelo Teorema de Holder e N igual a 1 pelo Teorema de Solodov, nosso próximo passo será classificar o caso N igual a 2. Para isso, iremos introduzir a noção de Abertura de Órbita como uma semi-conjugação dos grupos de homeomorfismos. / [en] We have as main objective to classify, by semi-conjugation, the groups of increasing homeomorphisms of the line, with at most N fixed points. Starting with the cases already classified, N equal to 0 by Holder s Theorem and N equal to 1 by Solodov s Theorem, our next step will be to classify the case N equal to 2. For this, we will introduce the notion of Orbital Opening as a semiconjugation of the groups of homeomorphisms.

[pt] Esta tese investiga as propriedades eletrônicas de sistemas nanoscópicos com interações de muitos corpos, dando origem ao efeito Kondo. Primeiramente estudamos a transição SU(4)-SU(2) devido a um campo magnético externo e as propriedades de filtro de spin de um nanossistema de dois pontos quânticos capacitivamente acoplados. A transição é caracterizada pela diferença entre as polarizações de spin da ocupação eletrônica nos dois pontos quânticos, como uma função do potencial de porta aplicado sobre os pontos quânticos. Apesar do fato de que o campo magnético externo quebra a simetria SU(4) do Hamiltoniano, o estado fundamental a preserva, como uma propriedade emergente, na região do espaço de parâmetros onde os elétrons não estão polarizados. As propriedades de filtro de spin devido à população eletrônica spin polarizada nos pontos quânticos também é discutida. Estas propriedades são estudadas usando o formalismo dos operadores de projeção, que descreve de forma muito acurada a física associada ao estado fundamental dos sistemas Kondo. No capítulo subsequente, analisamos os efeitos da interação spin-órbita num ponto quântico conectado a contatos, representados pelo modelo da impureza de Anderson no efeito Kondo. Contrariamente ao resultado prévio de vários outros autores, nós mostramos que a interação spin-órbita reduz exponencialmente a temperatura Kondo enquanto a ação da interação no próprio ponto quântico pode ser um mecanismo de destruição do regime Kondo, conforme quebra a simetria SU(2). Usando o modelo de Anderson com acoplamento spin-órbita nós propomos um transistor de spin feito de um ponto quântico conectado a uma nanofaixa submetida à interação spin-órbita Rashba, depositada sobre um substrato ferromagnético. O ponto quântico também é conectado a dois contatos metálicos laterais, através do qual a corrente flui ao longo do sistema. A interação spin-órbita Rashba cria um mecanismo de inversão do spin no ponto quântico. Nós mostramos que o sistema é capaz de operar como um transistor de spin. / [en] This thesis investigates the electronic properties of nanoscopic systems under the presence of many body interactions, given rise to the Kondo effect. Firstly we studied the SU(4)-SU(2) crossover driven by an external magnetic field and the spin-filter properties of a capacitively coupled double quantum dot nanosystem. The crossover is characterized by the difference between the spin polarization of the electronic occupation at the double quantum dot, as a function of the gate potential applied to the quantum dots. Despite the fact that the external magnetic field breaks the SU(4) symmetry of the Hamiltonian, the ground state preserves it, as an emergent property, in a region in the parameter space where the electron are not polarized. The spinfilter properties due the spin polarized electronic population at the dots is also discussed. These properties are studied using the projector projection operator approach, which describes very accurately the physics associated to the ground state of Kondo systems. In a subsequent chapter, we analyze the effect of the spin-orbit interaction in a quantum dot connected to leads, represented by the Anderson impurity model on the Kondo effect. Contrary to several other authors previous results, we show that the Rashba spin-orbit interaction exponentially reduces the Kondo temperature while the action of the interaction on the quantum dot itself could be a mechanism of destroying the Kondo regime, as it breaks SU(2) symmetry. Using the Anderson model with spin-orbit coupling we propose a spin transistor device made of a quantum dot connected to a Rashba spinorbit interacting nanoribbon, deposited on a ferromagnetic substrate. The quantum dot is also connected to two lateral metallic contacts, through which the current flows along the system. The Rashba spin-orbit interaction creates a spin-flip mechanism at the quantum dot. We show that the system is capable of operating as a spin-transistor.

Submitted by ARMANDO ARQUIMEDES PEZO LOPEZ (armandopezo333@gmail.com) on 2017-09-15T18:49:05Z No. of bitstreams: 1 pezo_a_ms_ift.pdf: 7486652 bytes, checksum: 7101195a7ca026fe9e98885ba89961f1 (MD5) / Approved for entry into archive by Monique Sasaki (sayumi_sasaki@hotmail.com) on 2017-09-19T17:23:53Z (GMT) No. of bitstreams: 1 pezolopez_aa_me_ift.pdf: 7486652 bytes, checksum: 7101195a7ca026fe9e98885ba89961f1 (MD5) / Made available in DSpace on 2017-09-19T17:23:53Z (GMT). No. of bitstreams: 1 pezolopez_aa_me_ift.pdf: 7486652 bytes, checksum: 7101195a7ca026fe9e98885ba89961f1 (MD5) Previous issue date: 2016-08-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / A realização experimental do grafeno em 2004 abriu as portas para os estudos de uma nova geração de materiais, estes chamados materiais bidimensionais são a expressão final do que poderíamos pensar em material plano (monocamada) que, eventualmente, podem ser empilhados para formar o bulk. O grafeno oferece uma grande variedade de propriedades físicas, em grande parte, como o resultado da dimensionalidade de sua estrutura, e pelas mesmas razões, materiais como Fosforeno (P), Siliceno (S), Nitreto de Boro hexagonal (hBN), dicalcogenos de metais de transição (TMDC), etc. São muito interessantes para fins teóricos, como para futuras aplicações tecnológicas que podem-se desenvolver a partir deles, como dispositivos de spintrônica e armazenamento. Neste trabalho o estudo desenvolvido são as propriedades eletrônicas dos materiais apresentados acima (grafeno, fosforeno e MoTe 2 ), e além disso, ja que o acoplamento spin-órbita aumenta à medida que o número atômico tambem aumenta, espera-se que este parâmetro desempenhe um papel na estrutura eletrônica, particularmente para os TMDC’s. Começamos descrevendo genéricamente esses três sistemas, isto é, para o grafeno, podemos usar uma abordagem tipo tight binding, a fim de encontrar a dispersão de energia para as quase-particulas perto do nível de Fermi (Equação de Dirac). Usando cálculos DFT estudou-se de forma geral as propriedades desses sistemas com a inclusão do espin órbita. Abordou-se cálculos para descrever os efeitos do acoplo spin órbita sobre os materiais isolados, tambem nas heterostruturas (duas camadas formadas por eles). Finalmente, tambem estudou-se a possibilidade de defeitos e sua possível influência sobre a estrutura eletrônica das heterostruturas. / The experimental realization of graphene in 2004 opened the gates to the studies of a new generation of materials, these so-called 2 dimensional materials are the final expression of what we could think of a plane material (monolayer) that eventually can be stacked to form a bulk. Graphene, the wonder material, offers a large variety of physical properties, in great part, as the result of the dimensionality of its structure, and for the same reasons, materials like phosphorene(P), silicene(S), hexagonal Boron Nitride (hBN), transition metal dichalcogenides(TMDC), etc. are very interesting for theoretical purposes, as for the future technological applications that we can develope from them, such as Spintronics and Storage devices. In this dissertation we theoretically study the electronic properties of the materials presented above (graphene, Phosphorene and MoTe2), and besides that, since the spin-orbit coupling strength increases as the atomic number does, we expect that this paremeter plays a role in the electronic structure, particularly for the TMDC. We start describing generically those three systems using density functional theory including the effect of spin orbit. We address calculations to describe the effects of spin orbit on the isolated materials as well as the heterostructures. Finally we also include the possibility of defects in graphene and their possible influence on the electronic structure of heterostructures.

This master’s thesis deals with satellite transponders. Firstly, satellite communication basics, satellite services definitions, frequency bands and satellite orbits are investigated. The second chapter forms the satellite transponders analysis. The transparent transponder and the transponder with on-board processing are described. Finally, a transponder model is designed and simulated in communication chain.