Watson and Crick’s double-helical model of DNA is considered to be one of the great discoveries in biology. However, in 1976, two groups of scientists, one in New Zealand, the other in India, independently published essentially the same radical alternative to the double helix. The alternative, Side-By-Side (SBS) or ‘warped zipper’ conformation for DNA is not helical. Rather than intertwine, as do Watson and Crick’s helices, its two exoskeletal strands are topologically independent. Thus, unlike the double helix, they may separated during replication without unwinding. This dissertation presents, but does not arbitrate among scientific arguments. Its concerns are meta-scientific; in particular, why and how the individuals who invented the & ‘warped zipper’ came to do so. Against Popper and most recent philosophers of science, it is taken to be “the business of epistemology to produce what has been called a ‘rational reconstruction’ of the steps that have led the scientist to a discovery [Popper (1972), p.31, emphasis in the original].” On the received view, the invention of the ‘warped zipper’ must be irrational or, at best, non-rational thereby excluding from philosophical investigation. I establish that this philosophical dogma is not true a priori, as is usually supposed, and, in the case of the SBS structure of DNA, false a posteriori. The motivation for, and development of the SBS structure for DNA reveals a process best characterized as significantly, though not entirely, rational.

Thesis (Ph. D.)--University of Hong Kong, 2006. / Title proper from title frame. Also available in printed format.

Cette thèse est consacrée à l'étude de certains processus aléatoires à valeurs dans les arbres continus. Nous définissons d'abord un cadre conceptuel pour cette étude, en construisant une topologie polonaise sur l'espace des R-arbres localement compacts, complets et munis d'une mesure borélienne localement finie. Cette topologie, dite de Gromov-Hausdorff-Prokhorov, permet alors la définition de processus de Markov à valeurs arbre. Nous donnons ensuite une nouvelle construction du processus d'élagage d'Abraham-Delmas-Voisin, qui est un exemple de processus qui prend ses valeurs dans les arbres de Lévy. Notre construction, qui dévoile une nouvelle structure généalogique des arbres de Lévy, est trajectorielle, et permet d'identifier explicitement les transitions du processus d'élagage. Nous appliquons cette description à l'étude de certains temps d'arrêt, comme le premier temps auquel le processus franchit une hauteur donnée. Nous décrivons le processus à cet instant grâce à une nouvelle décomposition de type spinal. Enfin, nous nous intéressons à la fragmentation d'Aldous-Pitman de l'arbre brownien d'Aldous. En particulier, nous étudions, à la suite d'Abraham et Delmas, l'effet de cette fragmentation sur les sous-arbres discrets de l'arbre brownien. Le nombre de coupures nécessaires avant d'isoler la racine, convenablement renormalisé, converge vers une variable aléatoire de Rayleigh ; nous donnons un théorème central limite qui précise les fluctuations autour de cette limite

This thesis analyzes some aspects of electromagnetic wave propagation in double negative materials. Double negative materials have negative refractive indices. They are backward-wave materials. Plane waves undergo negative refraction at interfaces between double positive and double negative media. Causality principle implies these properties. High frequency plane wave scattering from a double negative infinitely long cylinder has been analyzed by using modified Watson transform, geometrical optics and Mie series. Mie series results and the modified Watson transform results have been found to be in good agreement. Hence, the physical mechanism of the scattering has been revealed.

Georgia statesman Thomas E. Watson is best known as a Vice-Presidential and Presidential candidate for the People’s Party, the progressive third party movement of the 1890s and 1900s. As a Populist candidate, Watson advocated a racially progressive platform in order to appeal to African American voters. But following a series of electoral defeats and the collapse of the Populist Party, Watson retreated from politics and began a career as the publisher of his own weekly and monthly periodicals. As a publisher, Watson utilized his editorial space to express bigoted attitudes towards African Americans, Catholics, and Jews, that greatly contrasted with views he espoused as a Populist. But Watson’s rhetorical shifts occurred during the industrialization, urbanization, and immigration of the South. These radical transformations inspired fear and anxiety for thousands of rural white southerners. Within this context, Watson, as the proprietor of a profit-driven enterprise, offered opinions about the era’s numerous social, political, and economic upheavals that his readership appreciated. Throughout his career, Watson’s rhetoric shifted with the ebb and flow of contextual variation and in this period of intense economic, social, and political change, the context was favorable for the bigoted opinions that he expressed.

This dissertation argues that a number of works of Canadian fiction usually designated as modernist fit more properly into the category of “late modernism”: a category that has only recently begun to emerge as a bridge between post-war modernism and emergent postmodernism. These works are aligned by their use of abstract, absurdist, or surrealist narrative structures and consequently by their refusal to adhere to conventional strictures of social realism. Because of this refusal, literary critics have identified the late-modernist emphasis on narrative form as necessarily ahistorical or apolitical. Conversely, I argue, these works are socially and politically engaged with the historical contexts and material conditions of their inception, composition, and consequent reception. I argue herein that the works of Sheila Watson, Elizabeth Smart, Malcolm Lowry, and John Glassco tend towards non-representational narrative forms, and in doing so, they engage in modes of cultural critique. These critiques are focused by a negotiation of what has been multiply identified as a “contradiction” in modernist art: while on the one hand the texts break with traditional forms of social-realist narrative out of a need to find new forms of expression in an effort to rebel against conservative, bourgeois sensibilities, on the other hand they are always produced from within the self-same socio-political economy that they critique. Whether this position is identified as a “modernist double bind” (following Willmott) or a “central paradox” of modernism (following Eysteinsson), I have argued that each author negotiates these internal contradictions through the integration of autobiographical material into their writing. In reading these works as part of a unified late-modernist narrative tradition, this dissertation aims to destabilize critical and popular understandings of mid-century Canadian prose and argue for an alternate reading of artistic interpretation of the twentieth-century Canadian condition. Such a reading challenges current canon formation because it destabilizes traditional critical accounts of these texts as instances of eccentric expression or singular moments of genius. Instead, we are asked to consider seriously the tendency for play with subjectivity and autobiographical material as an interpretive strategy to express the mid-century, post-war condition.

Lindenmayer (L) systems form a class of interesting computational formalisms due to their parallel nature, the various circumstances under which they operate, the restrictions imposed on language acceptance, and other attributes. These systems have been extensively studied in the Formal Languages literature. In the past decade a new type of Lindenmayer system had been proposed: Watson-Crick Lindenmayer Systems. These systems are essentially a marriage between Developmental systems and DNA Computing. At their heart they are Lindenmayer systems augmented with a complementary relation amongst elements in the system just as the base pairs of DNA strands can be complementary with respect to one another. When conditions and a mechanism for 'switching' the state of a computation to it's complementary version are provided then these systems can become surprisingly more powerful than the L systems which form their backbone. This dissertation explores the computational power of new variants of Watson-Crick L systems. It is found that many of these systems are Computationally-Complete. These investigations differ from prior ones in that the systems under consideration have extended alphabets and usually Regular Triggers for complementation are considered as opposed to Context-Free Triggers investigated in previous works. / Thesis (Master, Computing) -- Queen's University, 2010-12-06 18:29:23.584

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

This paper studies the use of Monte Carlo simulation techniques in the field of econometrics, specifically statistical inference. First, I examine several estimators by deriving properties explicitly and generate their distributions through simulations. Here, simulations are used to illustrate and support the analytical results. Then, I look at test statistics where derivations are costly because of the sensitivity of their critical values to the data generating processes. Simulations here establish significance and necessity for drawing statistical inference. Overall, the paper examines when and how simulations are needed in studying econometric theories.

A DESCRIPTIVE STUDY ON THE CRITICAL THINKING LEVELS OF THE STUDENTS AT THE UNIT OF ENGLISH PREPARATORY SCHOOL AT HACETTEPE UNIVERSITY