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[en] CYCLIC MINIMAL SURFACES IN R3, S2 X R AND H2 X R / [pt] SUPERFÍCIES MÍNIMAS CÍCLICAS EM R3, S2 X R E H2 X RLEANDRO TAVARES DA SILVA 06 March 2008 (has links)
[pt] Nesse trabalho descrevemos superfícies mínimas mergulhadas
em espaços produtos M x R, onde M = R2, S2 e H2 que são
folheadas por
geodésicas
(superfícies regradas ) e curvas de curvatura constante de
M (supefícies
cíclicas ). Em R2xR, ou seja, em R3 vamos demonstrar que
só existem duas
superfícies mínimas cíclicas, que são o catenóide e o
exemplo de Riemann.
Em seguida caracterizamos as superfícies mínimas cíclicas
em S2 x R que
formam uma família a dois parâmetros e por fim exibimos
três famílias de
dois parâmetros de superfícies mínimas cíclicas em H2 x R. / [en] In this work we describe minimal surfaces embedded in
product spaces
M x R, where M = R2, S2 and H2 which are foliated by
geodesics (ruled
surfaces) and curves of M with constant curvature (cyclic
surfaces). In
R2 x R, i.e. R3, we shall prove that there exist only two
minimal cyclic
surfaces which are the catenoid and the Riemann example.
Then we
characterize minimal cyclic surfaces in S2 x R; they form
a two-parameter
family. Finally we exhibit three two-parameter families of
minimal cyclic
surfaces in H2 x R.
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Application de la théorie de la révision des connaissances au raisonnement à partir de cas / Application of the Belief Revision Theory to the Case-Based ReasoningCojan, Julien 21 October 2011 (has links)
Le raisonnement à partir de cas est un modèle de raisonnement dont le but est de résoudre des problèmes à partir de l'expérience de résolution de problèmes connus, appelés cas sources. Une solution tirée d'un cas source peut ne pas être applicable directement au problème traité, il faut alors l'adapter. Nous nous intéressons dans cette thèse à une approche de l'adaptation qui s'appuie sur la théorie de la révision des connaissances. La révision des connaissances consiste à modifier des connaissances initiales pour prendre en compte de nouvelles connaissances avec lesquelles elles peuvent être en contradiction. Comme pour l'adaptation, les modifications apportés aux connaissances sont minimales. Ce rapprochement entre adaptation et révision permet de s'appuyer sur la formalisation logique de la révision pour donner un cadre formel à l'adaptation. Dans ce but nous définissons des opérateurs de révision dans des formalismes utiles au raisonnement à partir de cas : dans un formalisme attributs-valeurs simples et dans une logique de descriptions expressive (ALC). Nous montrons aussi que plusieurs approches de l'adaptation précédemment définies peuvent être mises sous la forme d'adaptation par la révision. Nous considérons aussi une extension de l'adaptation par la révision à une combinaison de cas où ce n'est plus un seul mais plusieurs cas sources qui sont exploités pour résoudre un problème. Cette approche de combinaison de cas s'appuie sur la fusion contrainte de connaissances qui généralise la révision. Ces travaux ont été appliqués dans le système d'élaboration de recettes de cuisine Taaable pour l'adaptation des quantités d'ingrédients suivant le modèle de l'adaptation par la révision / Case-Based Reasoning is a reasoning model for problem resolution by reusing the experience of previously solved problems, called source cases. The solution given by a source case cannot always be applied directly to a target case, it may need to be adapted. We focus in this thesis on an adaptation approach defined thanks to belief revision. The belief revision theory deals with the changes to apply to some initial knowledge in order to integrate possibly conflicting new knowledge. For both adaptation and belief revision, the changes are minimal. This parallel between adaptation and revision enables the adaptation process to benefit from the logical formalisation of belief revision. The definition of adaptation by revision aims at providing a formal framework to adaptation. For this purpose, we define revision operators in useful formalisms for case-based reasoning : a revision operator in attributes-simple values and an operator in an expressive description logic (ALC ). We show as well that several adaptation approach previously defined could be expressed as adaptation by revision. In addition we consider generalising the adaptation by revision to a case combination that takes into account more than one source case to solve a problem. This approach to case combination is defined thanks to integrity constrains belief merging that generalises belief revision. These results were applied in the cooking recipe elaboration system Taaable for ingredient quantities adaptation
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An infinite family of links with critical bridge spheresRodman, Daniel 01 May 2017 (has links)
A closed, orientable, splitting surface in an oriented 3-manifold is a topologically minimal surface of index n if its associated disk complex is (n-2)-connected but not (n-1)-connected. A critical surface is a topologically minimal surface of index 2. In this thesis, we use an equivalent combinatorial definition of critical surfaces to construct the first known critical bridge spheres for nontrivial links.
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C¹,α regularity for boundaries with prescribed mean curvatureWelch, Stephen William 01 December 2012 (has links)
In this study we provide a new proof of C¹,α boundary regularity for finite perimeter sets with flat boundary which are local minimizers of a variational mean curvature formula. Our proof is provided for curvature term H∈LΩ. The proof is a generalization of Cafarelli and C#243;rdoba's method, and combines techniques from geometric measure theory and the theory of viscosity solutions which have been developed in the last 50 years. We rely on the delicate interplay between the global nature of sets which are variational minimizers of a given functional, and the pointwise local nature of comparison surfaces which satisfy certain PDE. As a heuristic, in our proof we can consider the curvature as an error term which is estimated and controlled at each point of the calculation.
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Vergleichende Analyse von Antigenexpressionsmustern kindlicher cALL-Blasten und gesunden B-Zellvorstufen – Nutzen für die MRD Diagnostik / Comparative analysis of antigen expression on cALL blasts and healthy B cell progenitors – Use for MRD diagnosticsHempel, Katharina January 2019 (has links) (PDF)
Die MRD Diagnostik ist von erheblicher Bedeutung für die Risikostratifizierung kindlicher Leukämien. Um aber gesunde, sich regenerierende Vorstufen von blastären Zellen unterscheiden zu können ist die genaue Kenntnis des Antigenverlaufs sowohl der Vorstufen der B-Zellreihe als auch der Blasten notwendig. In dieser Arbeit wird eine Vergleichende Analyse von B-Zellvorstufen und Blasten mittels Durchflusszytometrie durchgeführt. Von besonders diskriminativem Wert waren die Vorläufermarker CD10, CD34, sowie die lymphatischen Marker CD19, CD20, CD22, CD45, cyCD79a und cyTdT.
Zur Beschreibung des individuellen LAIP eigneten sich vor allem die Marker CD11b, CD38, CD58, CD123 und CD133, sowie die myeloischen Marker CD13 und CD33.
Die Bessere Unterscheidung zwischen gesunden und kranken Zellen zusammen mit neuen Entwicklungen in Diagnostik und Therapie muss in Zukunft zur weiteren Verbesserung der Überlebensraten, auch im Rezidiv führen. / MRD diagnostic is important for the ongoing therapy of cALL in children. For better discrimination between blasts and b-cell progenitors we used flow cytometry to analyse the antigen expression on b cell progenitors with those on cALL blasts.
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Minimal music: roles and approaches of teachers engaging students with a contemporary art music through composing activitiesBlom, Diana Mary January 2001 (has links)
Since it arose in the 1960s, the minimalist aesthetic has increasingly influenced composers of art and popular music around the world and, in turn, minimalist composers have drawn on the compositional ideas of Western popular music and several non-Western musics. Educationally, minimal music offers much potential for music in the classroom as it embodies a number of musical characteristics known to, and preferred by, students aged 9-18 years at primary, secondary and first year tertiary level. Socially, it offers teachers an opportunity to engage students, through composing activities, with contemporary society. The study aims, firstly, to analyse compositions by students aged 9, 12, 15 and 18 years and their teachers, seeking pastiche development of, and compositional expansion beyond, the musical concepts presented in a resource booklet of projects, The Pulse Music Album. Secondly, this study aims to investigate how nineteen participating teachers in three countries engage their students with minimalist composing activities stimulated through the resource booklet. The study attempts to determine why teachers adopt their particular roles and strategies by examining music qualifications, preferences and experience, teaching perspectives and teaching environments. It also seeks to identify reasons why one group of teachers submitted pieces which were pastiches of those presented in the projects and another group submitted compositions which moved well beyond pastiche into an expansion of these same musical concepts and argues for this as evidence of dialogue with contemporary society. Conclusions drawn from the findings note that while there are many commonalities between the backgrounds and approaches of both groups of teachers, there are clearly observed differences. These differences suggest approaches to classroom composition for consideration by practising classroom teachers, in-service instructors and teacher training institutions.
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Vergleichende Untersuchungen zur Kastration von Bullenkälbern durch Alteration der Blutgefäe im Funiculus spermaticus mit Hilfe der Diathermie, durch Kompression mittels der Burdizzo-Zange sowie einer transkutanen LigaturGierschner, Peter January 2003 (has links)
Zugl.: Freie Univ., Diss., 2003 / Dateiformat: zip, Dateien im PDF-Format
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An Analysis of Gender Differences in Minimal ResponsesBased on the Cartoon Show <em>The Simpsons</em>Sijin, Fang January 2008 (has links)
<p>Based on the cartoon show <em>The Simpsons, </em>the present investigation finds out that there are differences in the communicative competence between male and female speakers, especially the selected characters from the cartoon show, in terms of their use of minimal responses. The focus will be on the frequency, type and function of male and female usage of minimal responses.</p>
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Classification of perfect codes and minimal distances in the Lee metricAhmed, Naveed, Ahmed, Waqas January 2010 (has links)
Perfect codes and minimal distance of a code have great importance in the study of theoryof codes. The perfect codes are classified generally and in particular for the Lee metric.However, there are very few perfect codes in the Lee metric. The Lee metric hasnice properties because of its definition over the ring of integers residue modulo q. It isconjectured that there are no perfect codes in this metric for q > 3, where q is a primenumber.The minimal distance comes into play when it comes to detection and correction oferror patterns in a code. A few bounds on the number of codewords and minimal distanceof a code are discussed. Some examples for the codes are constructed and their minimaldistance is calculated. The bounds are illustrated with the help of the results obtained.
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Minimal model for the secondary structures and conformational conversions in proteinsImamura, Hideo January 2005 (has links)
Better understanding of protein folding process can provide physical insights on the function of proteins and makes it possible to benefit from genetic information accumulated so far. Protein folding process normally takes place in less than seconds but even seconds are beyond reach of current computational power for simulations on a system of all-atom detail. Hence, to model and explore protein folding process it is crucial to construct a proper model that can adequately describe the physical process and mechanism for the relevant time scale. We discuss the reduced off-lattice model that can express <em>α</em>-helix and <em>β</em>-hairpin conformations defined solely by a given sequence in order to investigate a protein folding mechanism of conformations such as a <em>β</em>-hairpin and also to investigate conformational conversions in proteins. The first two chapters introduce and review essential concepts in protein folding modelling physical interaction in proteins, various simple models, and also review computational methods, in particular, the Metropolis Monte Carlo method, its dynamic interpretation and thermodynamic Monte Carlo algorithms. Chapter 3 describes the minimalist model that represents both <em>α</em>-helix and <em>β</em>-sheet conformations using simple potentials. The native conformation can be specified by the sequence without particular conformational biases to a reference state. In Chapter 4, the model is used to investigate the folding mechanism of <em>β</em>-hairpins exhaustively using the dynamic Monte Carlo and a thermodynamic Monte Carlo method an effcient combination of the multicanonical Monte Carlo and the weighted histogram analysis method. We show that the major folding pathways and folding rate depend on the location of a hydrophobic. The conformational conversions between <em>α</em>-helix and <em>β</em>-sheet conformations are examined in Chapter 5 and 6. First, the conformational conversion due to mutation in a non-hydrophobic system and then the conformational conversion due to mutation with a hydrophobic pair at a different position at various temperatures are examined.
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