21 resultados para representability


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To a reasonable approximation, a secondary structures of RNA is determined by Watson-Crick pairing without pseudo-knots in such a way as to minimise the number of unpaired bases: We show that this minimal number is determined by the maximal conjugacy-invariant pseudo-norm on the free group on two generators subject to bounds on the generators. This allows us to construct lower bounds on the minimal number of unpaired bases by constructing conjugacy invariant pseudo-norms. We show that one such construction, based on isometric actions on metric spaces, gives a sharp lower bound. A major goal here is to formulate a purely mathematical question, based on considering orthogonal representations, which we believe is of some interest independent of its biological roots.

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Given a function from Z(n) to itself one can determine its polynomial representability by using Kempner function. In this paper we present an alternative characterization of polynomial functions over Z(n) by constructing a generating set for the Z(n)-module of polynomial functions. This characterization results in an algorithm that is faster on average in deciding polynomial representability. We also extend the characterization to functions in several variables. (C) 2015 Elsevier B.V. All rights reserved.

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The atlas is an attempt, unique in the history of representation of Aboriginal traditional narratives in Australia, to bridge the gap between Western and Aboriginal narrative style by focusing on a single coherent culture. Here, Devlin-Glass describes and analyzes a new hybrid mapping of Yanyuwa kujika in a limited edition cultural atlas.

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In this paper we consider polynomial representability of functions defined over , where p is a prime and n is a positive integer. Our aim is to provide an algorithmic characterization that (i) answers the decision problem: to determine whether a given function over is polynomially representable or not, and (ii) finds the polynomial if it is polynomially representable. The previous characterizations given by Kempner (Trans. Am. Math. Soc. 22(2):240-266, 1921) and Carlitz (Acta Arith. 9(1), 67-78, 1964) are existential in nature and only lead to an exhaustive search method, i.e. algorithm with complexity exponential in size of the input. Our characterization leads to an algorithm whose running time is linear in size of input. We also extend our result to the multivariate case.

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Having as a starting point the characterization of probabilistic metric spaces as enriched categories over the quantale , conditions that allow the generalization of results relating Cauchy sequences, convergence of sequences, adjunctions of V-distributors and its representability are established. Equivalence between L-completeness and L-injectivity is also established. L-completeness is characterized via the Yoneda embedding, and injectivity is related with exponentiability. Another kind of completeness is considered and the formal ball model is analyzed.

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This paper revisits Diamond’s classical impossibility result regarding the ordering of infinite utility streams. We show that if no representability condition is imposed, there do exist strongly Paretian and finitely anonymous orderings of intertemporal utility streams with attractive additional properties. We extend a possibility theorem due to Svensson to a characterization theorem and we provide characterizations of all strongly Paretian and finitely anonymous rankings satisfying the strict transfer principle. In addition, infinite horizon extensions of leximin and of utilitarianism are characterized by adding an equity preference axiom and finite translation-scale measurability, respectively, to strong Pareto and finite anonymity.

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This paper proposes a definition of relative uncertainty aversion for decision models under complete uncertainty. It is shown that, for a large class of decision rules characterized by a set of plausible axioms, the new criterion yields a complete ranking of those rules with respect to the relative degree of uncertainty aversion they represent. In addition, we address a combinatorial question that arises in this context, and we examine conditions for the additive representability of our rules.

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Single-peaked preferences have played an important role in the literature ever since they were used by Black (1948) to formulate a domain restriction that is sufficient for the exclusion of cycles according to the majority rule. In this paper, we approach single-peakedness from a choice-theoretic perspective. We show that the well-known axiom independence of irrelevant alternatives (a form of contraction consistency) and a weak continuity requirement characterize a class of single-peaked choice functions. Moreover, we examine the rationalizability and the rationalizability-representability of these choice functions.

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La transsexualité et son image représentent pour plusieurs une subversion ou une transgression de la binarité du genre. L’image de la transsexualité est souvent considérée en termes de représentation. Afin de questionner cette image transsexuelle, sa subversivité, sa transgressivité et même sa représentabilité, on tentera de la regarder autrement. Ce mémoire propose d'étudier l'image audiovisuelle de la transsexualité comme figure. Pour définir la figure, on la distinguera d'un autre concept esthétique : la représentation. Par l'analyse d'un film, Transamerica (2005), réalisé par Duncan Tucker, on verra comment certaines modalités donnent à voir la figure trans. Suite à cette analyse de la figure au cinéma, on rendra compte de la manière avec laquelle on a poursuivi, au moyen de la vidéo, la recherche qui concerne la question de la figure trans.

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Ce mémoire traite des Comedias bárbaras (« Águila de blasón », « Romance de lobos » et « Cara de plata », 1907-1908-1922) de Ramón María del Valle-Inclán (Espagne, 1866-1936), et en fait une interprétation novatrice, différente de la réception dominante. Inspiré par les études sur le genre, ce travail revisite la trilogie en mettant l’emphase sur la perspective des personnages féminins qui contraste avec la figure prépondérante du mythe de Lilith (ou l’idée de la responsabilité légendaire du péché qui repose sur la femme, démoniaque). L’analyse des relations de genre présentes dans l’œuvre apparaît primordiale étant donné que le personnage de Don Juan Manuel Montenegro est aussi une version de la légende de don Juan. De plus, en recensant les différents discours sur celui-ci ainsi que les éléments grotesques des récits, on perçoit dans le traitement du personnage principal une critique qui va au-delà de la société de l’époque, et qui révèle une critique universelle des logiques mêmes qui régissent le système patriarcal, en passant par une réflexion sur la légitimité du pouvoir. Toutes ces considérations permettent d’apprécier l’ensemble de la trilogie dans les aspects qui la rapproche de l’esthétique postérieure de l’esperpento. Cette interprétation contemporaine entre en dialogue avec les aspects centraux des différents débats qu’auront suscités ces œuvres depuis leur parution (représentabilité, genre littéraire, unité ou non de la trilogie, classification) et revitalise sa réception dans le XXIe siècle, révélant la fascinante actualité du théâtre de l’auteur.

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La present Tesi Doctoral, titulada desenvolupament computacional de la semblança molecular quàntica, tracta, fonamentalment, els aspectes de càlcul de mesures de semblança basades en la comparació de funcions de densitat electrònica.El primer capítol, Semblança quàntica, és introductori. S'hi descriuen les funcions de densitat de probabilitat electrònica i llur significança en el marc de la mecànica quàntica. Se n'expliciten els aspectes essencials i les condicions matemàtiques a satisfer, cara a una millor comprensió dels models de densitat electrònica que es proposen. Hom presenta les densitats electròniques, mencionant els teoremes de Hohenberg i Kohn i esquematitzant la teoria de Bader, com magnituds fonamentals en la descripció de les molècules i en la comprensió de llurs propietats.En el capítol Models de densitats electròniques moleculars es presenten procediments computacionals originals per l'ajust de funcions densitat a models expandits en termes de gaussianes 1s centrades en els nuclis. Les restriccions físico-matemàtiques associades a les distribucions de probabilitat s'introdueixen de manera rigorosa, en el procediment anomenat Atomic Shell Approximation (ASA). Aquest procediment, implementat en el programa ASAC, parteix d'un espai funcional quasi complert, d'on se seleccionen variacionalment les funcions o capes de l'expansió, d'acord als requisits de no negativitat. La qualitat d'aquestes densitats i de les mesures de semblança derivades es verifica abastament. Aquest model ASA s'estén a representacions dinàmiques, físicament més acurades, en quant que afectades per les vibracions nuclears, cara a una exploració de l'efecte de l'esmorteïment dels pics nuclears en les mesures de semblança molecular. La comparació de les densitats dinàmiques respecte les estàtiques evidencia un reordenament en les densitats dinàmiques, d'acord al que constituiria una manifestació del Principi quàntic de Le Chatelier. El procediment ASA, explícitament consistent amb les condicions de N-representabilitat, s'aplica també a la determinació directe de densitats electròniques hidrogenoides, en un context de teoria del funcional de la densitat.El capítol Maximització global de la funció de semblança presenta algorismes originals per la determinació de la màxima sobreposició de les densitats electròniques moleculars. Les mesures de semblança molecular quàntica s'identifiquen amb el màxim solapament, de manera es mesuri la distància entre les molècules, independentment dels sistemes de referència on es defineixen les densitats electròniques. Partint de la solució global en el límit de densitats infinitament compactades en els nuclis, es proposen tres nivells de aproximació per l'exploració sistemàtica, no estocàstica, de la funció de semblança, possibilitant la identificació eficient del màxim global, així com també dels diferents màxims locals. Es proposa també una parametrització original de les integrals de recobriment a través d'ajustos a funcions lorentzianes, en quant que tècnica d'acceleració computacional. En la pràctica de les relacions estructura-activitat, aquests avenços possibiliten la implementació eficient de mesures de semblança quantitatives, i, paral·lelament, proporcionen una metodologia totalment automàtica d'alineació molecular. El capítol Semblances d'àtoms en molècules descriu un algorisme de comparació dels àtoms de Bader, o regions tridimensionals delimitades per superfícies de flux zero de la funció de densitat electrònica. El caràcter quantitatiu d'aquestes semblances possibilita la mesura rigorosa de la noció química de transferibilitat d'àtoms i grups funcionals. Les superfícies de flux zero i els algorismes d'integració usats han estat publicats recentment i constitueixen l'aproximació més acurada pel càlcul de les propietats atòmiques. Finalment, en el capítol Semblances en estructures cristal·lines hom proposa una definició original de semblança, específica per la comparació dels conceptes de suavitat o softness en la distribució de fonons associats a l'estructura cristal·lina. Aquests conceptes apareixen en estudis de superconductivitat a causa de la influència de les interaccions electró-fonó en les temperatures de transició a l'estat superconductor. En aplicar-se aquesta metodologia a l'anàlisi de sals de BEDT-TTF, s'evidencien correlacions estructurals entre sals superconductores i no superconductores, en consonància amb les hipòtesis apuntades a la literatura sobre la rellevància de determinades interaccions.Conclouen aquesta tesi un apèndix que conté el programa ASAC, implementació de l'algorisme ASA, i un capítol final amb referències bibliogràfiques.

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n-dimensional fuzzy sets are an extension of fuzzy sets that includes interval-valued fuzzy sets and interval-valued Atanassov intuitionistic fuzzy sets. The membership values of n-dimensional fuzzy sets are n-tuples of real numbers in the unit interval [0,1], called n-dimensional intervals, ordered in increasing order. The main idea in n-dimensional fuzzy sets is to consider several uncertainty levels in the memberships degrees. Triangular norms have played an important role in fuzzy sets theory, in the narrow as in the broad sense. So it is reasonable to extend this fundamental notion for n-dimensional intervals. In interval-valued fuzzy theory, interval-valued t-norms are related with t-norms via the notion of t-representability. A characterization of t-representable interval-valued t-norms is given in term of inclusion monotonicity. In this paper we generalize the notion of t-representability for n-dimensional t-norms and provide a characterization theorem for that class of n-dimensional t-norms. © 2011 Springer-Verlag Berlin Heidelberg.

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In the new world order is notorious changes in social, ethical, economical and political aspects in the society, which reach incisively higher education, requiring a number of modifications and a new vision in nursing education, in order to meet the demands of the Unique Health System. Thus, the Higher Education Institutes (HEI) and teachers are invited to face new challenges and reflect on their practices, using pedagogical approaches and innovative methodologies to meet the requirements of a globalized society. This study has as an objective to analyze the perspective of teachers in what concern the pedagogical approaches used in nursing education and to identify pedagogical approaches utilized by teachers in nursing education. This is a field research of exploratory kind, descriptive, of quantitative approach. The search was conducted at the Department of Nursing of the Federal University of Rio Grande do Norte UFRN, based in the city of Natal. The population consisted of forty-six teachers. From this population was selected a sample of twenty teachers. Data collection occurred from August to September 2011, through the utilization of the technique of interview and questionnaire. The obtained data were analyzed in two moments. In the first moment, was carried out the quantitative analysis that refers to the obtained data through the interview technique, methodological procedures were submitted to the content analysis proposed by Bardin. On the second moment, concerning the quantitative analysis of the questionnaires applied to the teachers and of the identification data, which were digitized and transferred to a spreadsheet electronic of Microsoft Excel XP, tabulated and organized into tables, containing their relative and absolute frequencies. It is worth mentioning that were respected the aspects of the CNS Resolution 196/96. With regard to the characteristics of research participants, 20% were male; with a degree of titration of 55% doctorates; regarding time of service there was a greater representation from 15 to 45 years, with 45%. The results showed that 90% of teachers who participated in the research have an appropriate understanding of non-critical pedagogical approaches, only 10% had an inadequate understanding. However, 70% of teachers, despite having an adequate understanding, reported difficulties when attempting to implement these pedagogies. Most teachers, with representability of 80% consider the non-critical pedagogies relevant in nursing education, as well as critical pedagogies, being represented by 95% of teachers. It was concluded that both critical and non-critical pedagogies are in teachers practice of undergraduate nursing education. It feels like a moment of transition, since the presence of new ways of teaching as a part of this educational context, with educational models that give value to scientific, ethical and personal aspects in the educational process. The research contains limitations, however highlights the contribution of new possibilities for action, reflection on the context of performance, maximizing the pedagogical skills necessary to conduct teaching process, in line with the new educational paradigm of higher education

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)