VictorJuiz/thesis huggingface dataset:
Efficient cluster compensation for Lin-Kernighan heuristics

For certain problems such as the Traveling Salesman Problem, the Lin-Kernighan heuristic and its derivatives are among the most successful algorithms known to optimization practice. It usually runs quickly, producing nearly optimal answers. Unfortunately, run times are usually longer on sharply clustered instances than on more uniform instances. This dissertation introduces ' efficient cluster compensation', an algorithmic technique designed to reduce the performance penalty Lin-Kernighan suffers on clustered inputs. The technique aims to decrease running times while maintaining the quality of the answers produced. The strategy is to prune unfruitful portions of the search space by incorporating extra lookahead into the guiding utility function. The lookahead takes the form of the 'cluster distance' between two points, a value computed in constant time given modest preprocessing. Efficient cluster compensation reduces running times on nearly all inputs tested, not just sharply clustered instances. When it increases running times, the slowdown is not severe. Efficient cluster compensation therefore delivers overwhelming benefit at little or no cost. Heuristics are notorious for behaving unpredictably. Making algorithmic choices and tuning parameters is rightly described as a black art. A broader contribution of this thesis is a better understanding of the qualitative behaviour of the Lin-Kernighan heuristic. The key features of a worst-case result, Papadimitriou's proof that Lin-Kernighan solves a PLS-complete problem, are conjectured to be the cause of bad behaviour observed by Johnson. This intuition is validated by the performance improvement seen when cluster compensation is used, and by comparing several of the results with perturbed data. This thesis also introduces several novel instance generation algorithms. They are used to test the generalizability and the robustness of the experimental results reported in earlier chapters, and to test our intuition about the behaviour of the heuristic. The Lin-Kernighan heuristic is best known as a heuristic for the Traveling Salesman Problem. Yet the TSP heuristic is only one instance of the more general Lin-Kernighan strategy to which cluster compensation applies. We test cluster compensation using it in the Lin- Kernighan heuristic for the TSP and in a Lin-Kernighan heuristic for the minimum weight perfect matching problem.
Fibre characteristics and chemical pulping of Canadian industrial hemp (Cannabis sativa L.)

Efforts to increase Canadian fibre supply have provided an impetus for investigating Industrial Hemp ('Cannabis sativa' L.) in Canada as a possible supplementary fibre resource for the pulp and paper industry. Hemp fibre was grown and donated by Hempline Inc. (based near London, Ontario). The study focused on the composition and chemical pulping of Canadian Industrial hemp. The literature available on 'Cannabis sativa' L. fibre characteristics is scarce and Canadian grown hemp may have unique physical and chemical features. The study was divided into three distinct research components: fibre analysis, delignification kinetics and small scale pulping. The objectives of this study were to increase the knowledge base of non-wood fibres and to demonstrate the potential of hemp fibre as an additional resource for pulp and paper production. With reference to cell structure and material strength, hemp is similar to both hardwood and softwood tree species.
Peasant farming, the state, and food security in the north-western province of Zambia, 1902--1964

This study has demonstrated that in spite of state neglect and suppression at certain historical times, most of the peasants of North-Western province remained relatively food secure in colonial Zambia largely due to their resilience, initiative, and industriousness. The designation of the province as a labor reservoir made it a backwater in the territory's socio-economic and political configuration. This made it imperative that individual households become more resourceful in food production and/or acquisition. Local subsistence producers responded accordingly and adapted to neglect and, at times, contributed to the territory's food needs. To demonstrate the resilience of the local peasantry, and trends in food supply in the province, the study examines the origin, nature, extent, and consequences of the link between the local traditional agricultural economy, British South Africa Company, Crown government, Federal government, and the large mining network of Belgian Congo, Northern Rhodesia, Southern Rhodesia and South Africa between 1902 and 1964. Specifically, the study appraises the viability of the local agricultural economy in the sustenance of the peoples in the province, and its significance in the territory's political economy. The study critically analyzes the impact of ecological constraints, and the role of the colonial state/finance capital vis-a-vis local food supply, and peasant reaction thereto. It explores food security strategies, and survival strategies peasant farmers pursued to maintain and regain their food security, respectively. It also examines the role women and their children played in household food supply when men were coerced into labor migration. While past studies have variously examined the impact of the state, finance capital, colonial taxation, male labor migration, colonial legislation, market forces, and ecological constraints on food supply among societies in Sub-Saharan Africa, this study adds another dimension to the debate. It examines how colonized African societies, living in an official labor reservoir, remained resilient and relatively food secure against a backdrop of monumental constraints stacked against them.
The effects of cortisol on the development of the fetal hypothalamic-pituitary-adrenal axis

This thesis examines the effects of glucocorticoids on corticosteroid-binding globulin (CBG) and adrenocorticotrophic hormone (ACTH) in the fetus during late pregnancy. In fetal sheep, plasma corticosteroid-binding capacity (CBC) levels increased concomitantly with incremental cortisol infusion, and were abolished by fetal adrenalectomy. Therefore, CBG appears to be regulated by cortisol in the late-gestation ovine fetus. Conversely, in the human fetus at 0.75 of gestation, maternal glucocorticoid administration did not alter fetal plasma CBC levels. Cortisol infusion (96h) to the ovine fetus at 0.8 of gestation elicited an increase in plasma ACTH and CBC levels similar to that seen at term. The cortisol-induced increase in CBC maintained a low percentage of free cortisol in circulation (7%), but the absolute concentration of free cortisol increased. Therefore cortisol negative feedback at the pituitary was not attenuated and POMC mRNA levels were reduced in both the pars distalis by 96% and pars intermedia by 38%. However, there was no change in concentration of ACTH 1-39, ACTH+related peptides (RP), or the ratio of ACTH1-39 :ACTH+RP in the pars distalis. This may reflect a continued production and secretion of ACTH1-39 thereby contributing to the rise in plasma ACTH1-39, or secretion may cease such that the tissue peptide levels remain unchanged. In the latter case, the rise in plasma ACTH1-39 may be derived from a source outside the pars distalis. Potential sources include fetal lung and placenta. Cortisol did not suppress ACTH1-39 concentrations in the fetal lung or POMC mRNA and ACTH1-39 levels in the placenta. Therefore the lung and the placenta are potential sources of ACTH in the presence of elevated plasma cortisol concentrations. Cortisol treatment did not after prohormone convertase (PC) 1 mRNA levels in the fetal pituitary, lung or placenta. PC2 mRNA levels increased in the fetal pituitary, and placenta, but tissue and plasma Ã-melanocyte stimulating hormone (ÃMSH) concentrations did not change. Conversely, in the fetal lung PC2 mRNA levels and immunoreactive ÃMSH in the bronchiolar epithelium and alveoli were decreased after cortisol administration, which is consistent with a decrease in ACTH processing to ÃMSH by PC2 in the fetal lung. Therefore, intra-fetal administration of cortisol during late-gestation stimulates a rise in plasma ACTH1-39 that does not appear to be due to a decrease in cortisol feedback on the fetal pituitary, but may be due to a combined increase in ACTH1-39 output from the fetal pituitary, lung and placenta.
Role of oxidative stress in two models of insulin resistance within primary rat adipocytes

Insulin's major action is to increase the flux of glucose into insulin sensitive tissues. A decreased biological response to insulin, termed insulin resistance, is induced in adipocytes by chronic incubation in high glucose and insulin (high G/I), or glucosamine, or hydrogen peroxide. The hypothesis that resistance to insulin stimulated glucose uptake caused by high G/I and glucosamine is due to enhanced production of reactive oxygen species or oxidative stress was tested. Isolated rat adipocytes incubated in high G/I or glucosamine showed insulin resistance while the antioxidant and glutathione (GSH) precursor N-acetylcysteine (NAC) and GSH monoethyl ester prevented resistance. However, the antioxidant Ã-tocopherol and ebselen had no significant effect. Similarly the MAPKK (MEK) inhibitor, PD98059, and the p38 MAPK inhibitor, SB203580, could not prevent insulin resistance. Intracellular GSH was decreased by glucosamine, and increased by high G/I. NAC prevented the decreased levels of GSH caused by glucosamine. The data support a role for GSH in the pathogenesis of insulin resistance but the role of oxidative stress is not clear.
Matrix seriation, a relative dating technique for sites with multilinear stratigraphic sequences

The thesis contends that the underlying principles of stratigraphy and seriation are in need of revision. This is because both methods are incapable of addressing situations where the archaeological record is characterised by complex stratigraphy. Particularly on sites where architecture is present, the stratigraphy is often 'multilinear' consisting of several separate sequences of occupation. Where this occurs, the relationship of events occurring on separate 'lines' cannot be organised into a relative order using the principle of superposition. Artifact studies offer a potential solution to this problem but, such studies are grounded on the assumption of assemblage integrity. Seriation, the relative ordering of assemblages based on similarities between artifact types or attributes, is based on the underlying principle that artifacts contained in the assemblage are 'indigenous,' having been discarded at the time that the deposit was formed. A systematic study of site-formation processes indicates, however, that there are many factors responsible for the transformation of assemblage content following deposition. Consequently, objects in the assemblage that are non-indigenous (termed infiltrated and residual) can, in many cases, significantly alter the results of the seriation. The problem is compounded by the fact that, at present, there are no means of distinguishing between indigenous and non-indigenous remains within the assemblage. Results obtained by the uncritical application of seriation, therefore, may be spurious except in cases where assemblage integrity can be demonstrated. The thesis offers a solution to the problem of relative dating on sites characterised by complex stratigraphy by combining a technique of stratigraphic analysis referred to as the Harris matrix (developed by Edward Harris, 1973) and computerised seriation. The Harris matrix method is useful in that it offers a means of representing, schematically, the multilinear stratigraphic sequence characteristic of sites with complex sequences of occupation. Computerised seriation is applied as a way to order the events occurring on separate occupational sequences. Artifact assemblages used in the seriation represent indigenous remains, all non-indigenous remains having been removed prior to seriation. The procedure forms the basis of a relative dating technique referred to as 'Matrix Seriation.'
Applications and validation of models of heat transfer in perfused tissues

To improve treatment planning of thermal therapies, a better understanding of the effects of blood flow on temperature distributions is required. This thesis describes the experiments performed to measure temperature profiles of perfused heated tissues. The results were compared to predictions of mathematical models of tissue heat transfer which were then used to estimate lesion dimensions created during high intensity focused ultrasound (HIFU) therapy. An experimental system was built to provide accurate and reproducible high spatial resolution steady state and transient temperature profiles of heated tissues. By analyzing the temporal evolution of the temperature distribution of a fixed heated kidney as a function of flow we were able to demonstrate that predictions of the Bioheat Transfer Equation model (BHTE) were in good agreement with the experimental data but predictions of the scalar Effective Thermal Conductivity Equation model (ETCE) could not model the data. Using a similar experimental system, we investigated steady state and transient temperature distributions of heated tissues near large vessels and how they change as a function of flow. Temperature gradients of 6°C/mm were measured close to large vessels which could produce either excess heating or cooling in the target region. We demonstrated that the temperature gradients caused by large vessels were dependent on whether the heating source was highly localized or more distributed and that convective heat transfer by large vessels can heat regions distal to the treatment area. Optimal tissue heating strategies were proposed based on these results. It has been suggested that short duration high temperature treatments may overcome the effects of blood flow on the temperature distribution. A novel finite difference model was developed to examine how blood flow modifies tissue lesions created by HIFU. It was shown that the effects of tissue microvascular perfusion on lesion formation were significant for exposure times greater than 2 s for highly perfused tissues, but were not significant for up to 12 s in moderately perfused tissues such as muscle. Predictions of lesion size using the BHTE were in better agreement with the experimental lesion data than predictions of the ETCE.
Jewish identities in German popular entertainment, 1890-1930

My thesis evaluates how the political and cultural spheres intersected in the realm of German popular entertainment. I explore the ways in which Jewish artists were able to reveal their ethnic identities in public performance, and I examine the nature and aesthetics of the various dialogues between spectators and performers. Investigating an arena that has received only marginal attention in both German and German-Jewish historiography, I focus on three distinct entertainment genres in my dissertation: the mass medium of the circus, middle-class entertainment in Yiddish theaters, and upper-class revue theaters. My thesis demonstrates that by forming new spheres of sociability and enterprise, all three aesthetic genres created grey areas of Gentile-Jewish relations, blurring the boundaries between insiders and outsiders. This ambivalence is captured and evaluated by reconstructing the everyday in Germany's booming entertainment industry. In particular, I analyze how Jewish entertainers were able to capture and inform the aspirations of mass audiences. My study demonstrates that the evolution of German popular entertainment between 1890 and the late 1920s was strongly conditioned by Jewish entertainers and entrepreneurs. Drawing upon recent debates in German history, Cultural Studies and German-Jewish history, my study reevaluates the way contemporary Germans--Gentiles and Jews--thought about ethnic and cultural diversity in a time of rising nationalism.
The association between workplace hierarchy, workplace psycho-social factors and quality of life among workers at a Canadian manufacturing plant

This study examined the relationship between hierarchy in the workplace, stressful workplace conditions and quality of life. It was hypothesized that hourly shop-floor workers would suffer from relatively lower quality of life as compared to professionals, and that a substantial part of this association would be due to hourly workers experiencing more stress in the workplace. Sixty-four employees from an Ontario automotive-parts manufacturing company participated in the study. The concept of job stress was based on three models (Karasek's job strain model, Siegrist's effort-reward imbalance model, and the yin/yang communications model). The study found that employment grade level only predicted job strain, and not perceptions of fairness or effectiveness of communication. Although stressful working conditions, as defined by low control and high demand, perceptions of fairness, and good communication, were all good predictors of overall quality of life, job hierarchy was not.
The Indian "Act": Postmodern perspectives on Native Canadian theatre

Since the explosion of theatrical activity by Native artists in Canada since the 1980s, Native playwrights and performance artists have written and performed challenging representations of identity, representations in which irony, self-conscious manipulations of form, and investigations of subjecthood play a large part. It is of value to understand these works as contingent constructions, ones which foreground their own ontological premises the better to subject them to scrutiny. Native performance intervenes in representation by reminding us of its formal constraints. In its playful manipulation of form and identity, it can be seen to have both sympathies with and divergences from the aesthetic/philosophical discourses know collectively as "postmodern". The conjunction of postmodernism and Native performance permits a mutual transformation of means and ends, where the ideological agendas advanced by Native theatre make use of the tools of deconstruction to reinvent a "new" (yet immanently "traditional") conception of Native subjecthood. Similarly, this project calls into question whether the tropes of power implicit in postmodern theory are contingent or necessary. This thesis explores the ways in which postmodern theory selectively illuminates aspects of Native theatrical expression. Chapter 1 outlines the relative strengths and weaknesses of postmodern theory as an affirmative tool for Native explorations of identity. Chapter 2 begins a discussion of the potential ways Native theatre is perceived by an audience, and the tactics employed by Native performers to subvert the process of reification. Chapter 3 focuses upon the body in plays written by Native women, and how its materiality is both constituted (in part) and threatened by dominant discourse. Chapter 4 explores the affinity between postmodern ideas of history and the synchronic formulation of the past in Native performance. Chapter 5 extends the concept of trickster discourse to examine Native plays that interrogate the ideological underpinnings of narrative form.
Using what is to hand, to eye, to ear and to mind, a theory of the deaf writer's meaning-making

Using cultural historical activity theory as an analytic framework, this thesis is a descriptive study that, through an examination of the composing processes of four deaf student writers, attempts to capture some sense of what these learners do as they write, specifically in terms of what they do, what they know, and how they come to know and do these things as they write. The research was school-based, and data collected consisted of verbal and written reports from interviews and surveys done with the student participants, written language samples, and retrospective accounts of the composing process which were elicited through a prompted recall interview technique. The argument is made that deaf students manage the problem of composing English text via a particular set of mediating tools, with a particular emphasis in the discussion being placed on the respective roles that contact sign and American Sign Language play in mediating the composing process and how these two cultural artifacts are valued differently by the various stakeholders in the education of deaf students.
RNA and protein interactions in the yeast spliceosome

Nuclear pre-mRNA splicing proceeds in a protein-RNA complex, the spliceosome, via a two-step transesterification reaction. Five spliceosomal small nuclear RNAs; (snRNAs) are brought to the pre-mRNA substrate in a process known as spliceosome assembly. Extensive RNA-RNA interactions and conformational changes occur during spliceosome assembly and maturation. However, very little is known about how RNA conformational changes are coordinated between the two steps of the splicing reaction, and how recognition of the 3' splice site by other factors is connected to the function of U5 loop 1 prior to and following the first splicing step. I performed a genetic screen in order to identify factors that are important for the U2/U6 helix II interaction and/or the function of the 5' -end of U2 snRNA, on the basis of synthetic lethality with an 11nt nucleotide substitution in the 5'-end region of U2 snRNA that could also perturb the U2/U6 helix II interaction. Six Slt (synthetic lethal with U2 snRNA) factors were isolated in this screen. Slt11p and Slt22p are new splicing factors, while the remainder correspond to previously identified splicing factors, Slt15p/Prp17p, Slt16p/Smd3p, Slt17p/Slu7p and Slt21p/Prp8p. Slt22p is a large RNA-dependent ATPase, whose activity is preferentially stimulated by pre-annealed U2/U6 snRNAs. Biochemical and genetic analyses indicated that its function is associated with U2/U6 snRNA interaction and that it may unwind intermolecular helix II prior to the formation of the active spliceosome. Slt2lp/Prp8p has been shown to be required for both steps of the splicing reaction. The 'slt'21/'prp'8-21 mutation has been mapped to a domain in Prp8p that is important for the recognition of the polypyrimidine tract preceding the 3' splice site. It is synthetically lethal with mutations in only the U2 part of U2/U6 helix II. Consistent with the notion that the 5'-end of U2 snRNA plays a role in the second splicing step, I found that U2 mutations in this region are synthetically lethal with several second-step mutations, including 'slt15'/'prp17-100', ' slu4'/'prp17-2', 'slt17'/' slu7-100', and 'slu7-1'. Slt11p is a putative RNA-binding protein containing two Zn-finger motifs. Although 'SLT11' is essential for viability only at elevated temperatures, its product is required for the efficiency of the splicing reaction. In the absence of Slt11p, 'slt17'/'slu7-100' and mutations in specific regions of U2, U5 and U6 snRNAs become lethal. (Abstract shortened by UMI.)
Characterization of the trophic properties of GLP-2, a novel intestinal growth factor

The molecular factors that regulate intestinal growth, development and regeneration remain poorly understood. The experiments carried out in this thesis test the hypothesis that GLP-2 is a novel intestinal growth factor. GLP-2 induces bowel growth in male and female mice of different ages and at least 2 strains of mice. Daily injections over 3 months produced intestinal growth without causing histological abnormalities or tumorigenesis. The GLP-2 effect on bowel growth regresses following cessation of administration. GLP-2 did not cause teratogenic effect when administered to pregnant mice. Twenty-three analogues were screened. and some were more effective than the natural peptide. GLP-2-treated animals had increased crypt cell proliferation rates and decreased apoptotic cells compared to controls. Taken together, the results derived from these studies provide an initial characterization of GLP-2 in physiological and pharmacological aspects and facilitate the understanding of intestinal growth and adaptation.