VictorJuiz/thesis huggingface dataset:
Influence of relative humidity on the stress relaxation of sucrose compacts

Deformation kinetic analysis was used previously to develop a model to predict the viscoelastic deformation behavior of compacts composed of ductile material. This project was undertaken to extend and develop this model to evaluate the deformation kinetics of brittle pharmaceutical materials at various relative humidities. The effects of moisture on the deformation process are also hypothesized to be quantified by the same approach. Compacts were made from sucrose with various levels of pre-treated moisture content at compaction pressures of 3.5 and 4.5 MPa. Deformation kinetics indicated that plastic deformation will occur when the combined effect of stress and thermal energy increases the energy of the atoms to the point that the barrier to deformation can be overcome. The study proved that the deformation barrier of sucrose was symmetrical at equilibrium with a single energy barrier at lower humidity environments (relative humidity no more than 55%). Furthermore, this study was complicated by the fact that the deformation mechanism of the brittle material sucrose at ambient condition as different from that of the ductile material ('i.e'., NaCl and KBr) studied previously. A thorough investigation of the experimental results indicated that when the sucrose was compressed at ambient conditions (relative humidity beyond 67%), two energy barriers, combined in series, must be overcome before any final appreciable flow occurs. Two kinetic parameters, the activation energy and activation volume, were calculated from the experimental data.
Predictive accuracy of capitation rate adjusters, primary care and enrollment based practices

The purpose of this research project was to identify and evaluate capitation rate adjusters that could be used to fund a family practice for the provision of primary care services for rostered adults. A cross-sectional research design that involved stratified sampling was used to explain variability in the amount of time that physicians spent providing medical services. A survey research method that involved stratified, random sampling was used to predict the incidence of a visit, the frequency of visits among participants who visited at least once, and the annual payments made by the provincial health insurance plan. Participants were recruited from a large, academic, family practice in southwestern Toronto, Canada. Eleven physicians participated in both studies. Adults who participated in the Medical Minutes Study ('n' = 550; response rate: 80 percent) must have visited the practice on at least one prior occasion. Participants in the Visit/Payment Study ('n' = 659; response rate: 67 percent) must have met eligibility criteria to be considered rostered. Linear and logistic regression were used to identify significant determinants of physician resource utilization. The 'R'2 value was used to evaluate predictive accuracy at the individual-level and thereby assess the potential for bias selection in enrollment-based markets. The predictive ratio was used to evaluate accuracy at the group-level and thereby assess the potential financial impact of bias rosters. Primary care capitation formulae should adjust for age and gender, but the use of this demographic information is insufficient as it provides financial incentives for bias selection. The sizes of financial benefits from bias selection of healthy individuals do not appear to be as detrimental as the costs associated with differential selection of unhealthy people. There are potential adjusters that improved the predictive accuracy of capitation rate formula including: (a) prior use of physician services, (b) self-rated health status, (c) hospital admission, or (d) the socioeconomic context of residence. Adjusting for prior use would substantially improve the predictive accuracy of a formula and thereby reduce the undesirable consequences of bias selection and bias rosters. The inclusion of any of the other potential adjusters--solely or in combination--would improve predictive accuracy but not to the same extent as the more parsimonious age-gender-prior visit formula.
A longitudinal outcome study of lateral luxation injuries to the permanent maxillary incisors of children and adolescents

A longitudinal outcome study was undertaken to men variables that influence tooth survival, pulpal and periodontal outcomes of laterally luxated permanent maxillary incisors of children and adolescents. A sample of 42 patients (26 male and 16 female) with 58 laterally luxated incisors was identified. The mean age at the time of injury was 11.3 years (range. 6.3-17.8 years). Pulpal necrosis (PN) and pulp canal obliteration (PCO) were common healing complications. Cox and logistic regression analysis demonstrated that root development and extent of lateral luxation were not significantly related to PN and PCO ('p' > 0.05). This study represents the first to report incisor survival of children and adolescents following lateral luxations. In the entire sample (n = 58) no incisors were observed to fail. Therefore, parents can be informed that the survival prospects for laterally luxated incisors in children and adolescents are excellent.
Pricing credit derivatives and credit risk

We assume the unorthodox premise that every financial transaction is born from a 'disagreement' about its value. The focus is on credit derivatives, which involve the transfer of credit risk from one party to another. We discuss the pricing of a credit default swap, first from the risk-neutral perspective of the market maker. Then, turning to the risk/reward perspective of the investor on the other side of the trade, an approach is put forward based on utility functions, which does not require the Gaussian assumption behind Modern Portfolio Theory. We end with a discussion of derivative counterparty risk, and how to price the exotic default swap that hedges it.
The chronic effect of free fatty acids on glucose-stimulated insulin secretion in rats

We tested the 'in vivo' effect of a chronic FFA elevation on glucose-stimulated insulin secretion (GSIS) using a two-step hyperglycemic clamp at 13 and 22 mM of glucose in normal Wistar rats with a 48 hr i.v. infusion of either Intralipid+Heparin (IH), oleate, saline (SAL), or bovine serum albumin. IH decreased GSIS at high glucose levels, whereas oleate decreased GSIS at both low and high glucose. Further, to determine whether FFA results in a greater decrease of GSIS in obese and prediabetic rats, three additional groups of Zucker Fatty rats, obese and lean Zucker Diabetic Fatty rats with IH or SAL infusion were studied. Since IH induced insulin resistance, GSIS was more appropriately considered by relative GSIS (GSIS corrected for insulin resistance). Relative GSIS was impaired in all three groups of rats compared to normal Wistar rats. Conclusion: Prolonged elevation of FFA desensitizes the insulin secretory response to glucose ' in vivo' and this desensitization is accentuated in obese and prediabetic rats.
Rereading anecdotal moments, landscape for un-making the teacher

The aim of this thesis is to construct an inquiry to learn to reread anecdotal moments that could be constituted as 'just another instance' (of violence) in daily school life. This interrogative exploration identifies how one teacher lives the tensions and unresolveable contradictions in anecdotal moments through three identities: the non-native, the critical and the not yet tolerated. The text utilizes a theoretical matrix that embraces glimpses of a poststructuralist, postcolonialist and queer analysis. In those moments of learning to reread, the writer attempts to move her teacher identities through double narrative moments beyond the well-documented history of women teaching as a study of hetero/normativity. Rereading in this sense is the theoretical engagement with my queer bodily statements and questions that are committed to interrogating the ambivalence of 'the social' body, my body, as the teacher. The thesis is presented in three sections. In the first section, I attempt to unsettle the terms of 'normalcy' in an anecdotal moment--The Sandbox--to make the obviousness of normalcy strange. Throughout the rereadings in this anecdotal moment I interject and inject, between the pages, brief glimpses of moments lived in childhood, and as a teacher in the elementary school setting, as a means to make experience and history's memory visible through everyday acts of teaching. In the second section I engage what is so obviously absent--to make that which is seen as 'queer'--familiar. Central to what is presented in the body of the thesis is what re-structures affect, specifically shame, in daily life. By provoking the power of the excesses of shame, shame 'acts' as a rereading strategy to transgress the terms of normalcy. In the third and final section, I do the work to perform rereading practices in the anecdote--the Condom Crisis--where a queer pedagogy evokes positive sanctions to transgress and move the theoretical inquiry of shame, to a space of cultural negation as negotiation, beyond the impossibilities where identities discipline bodies and foreclose identificatory possibilities. In the moments of learning to reread, this text urges for an education that dares to provoke questions that reveal and draw attention to sexuality that query issues associated with stigmatized identities throughout compulsory education. This thesis is intended to challenge the teacher to rethink what it means to be an advocate concerned with social agency as an after effect of the intersubjective when an anecdotal moment is reread as crisis.
Nanotube engineering and science, synthesis and properties of highly ordered carbon nanotube arrays and Y-junction carbon nanotubes

Highly ordered carbon nanotube arrays and Y-junction carbon nanotubes were synthesized and studied for the first time. These new nanostructures demonstrate the next step towards engineering carbon nanotubes into functional materials for nanoscale science and technology. Highly ordered arrays were fabricated by chemical vapour deposition involving the decomposition of acetylene within hexagonally-disposed nanochannel alumina templates. The nanotube arrays are characterized by a narrow size distribution, large scale periodicity and high densities. Y-junction tubes were grown similarly in high density arrays, using Y-branched template channels. These novel nanotube junctions consist of a large diameter tube branching into two smaller diameter ones. Electronic transport measurements on Y-junction nanotubes showed them to possess intrinsic and reproducible rectifying behaviour at room temperature. The results could be explained by considering the change in bandgap across the junction caused by joining together different diameter nanotubes and illustrate a new type of semiconductor heterojunction for nanoelectronics.
Comparative seed ecology of native and alien plants of open uplands

Plant invaders may gain an advantage over natives because only enemy-free species are likely to invade (the predator filter hypothesis), or because invaders lose enemies while moving to a new area (the predator escape hypothesis). Working at the Joker's Hill Field Station, near Newmarket, Ontario, I have combined site descriptions, surveys, and experiments to investigate the role of predators and pathogens in seed ecology, and to understand their role in the establishment and spread of exotic species. Results indicate that seeds of both natives and exotics suffered significant losses to above-ground predators and below-ground pathogens. Losses varied among species and habitats; wetlands had particularly high levels of fungal mortality. Aliens and natives did not consistently differ in their susceptibility to predators and pathogens, even when analyzed using methods that controlled for phylogenetic biases. These results suggest natural enemies of seeds do not as a general rule determine invasive ability.
Manufacturing culture, the Soviet state and the Mayakovsky legend, 1930-1993

The present dissertation presents a study of the official Soviet image of the Russian poet Vladimir Mayakovsky (1893-1930) as an expression of Soviet cultural policy. It seeks to contribute to a re-appraisal of the poet's historical legacy behind the distortions of official culture by chronologically tracing the posthumous genesis, evolution and manipulation of the Mayakovsky legend. It also seeks to disprove the arguments advanced in some scholarship that Mayakovsky's canonization as official poet by the Stalin regime was predestined, and that the politically engaged Russian avant-garde in general provided the pre-suppositions of Socialist Realism. The dissertation begins by exploring aspects of the poet's own work and image of the self within the literary and political context of his own lifetime. The introduction outlines the poet's activity from 1917 to 1927, and the first chapter examines the last years of his life, which coincide with the onset of the Stalin era, in 1928-1930. These first two sections serve to propose an interpretation of the poet in contradistinction to the official legend, to which the large part of the dissertation is devoted. Chapter Two examines the immediate response to Mayakovsky's suicide, primarily by the regime but with consideration of unofficial sources. Chapter Three analyzes the reasons both for the initial ambivalence of the Soviet regime of the early thirties towards Mayakovsky's legacy, and for his abrupt canonization in 1935. Subsequent chapters trace the evolution and manipulation of the Mayakovsky legend according to the specific needs of cultural policy under Stalin, Khrushchev and Brezhnev respectively, and examine a number of significant attempts to challenge the official interpretation of Mayakovsky. The last chapter is devoted to the controversy surrounding Mayakovsky which emerged during the era of perestroika and glasnost. Finally, an Epilogue briefly considers the post-Soviet additude to Mayakovsky, particularly in light of the response to the centennary of his birth in 1993.
Mean meridional circulations in the middle atmosphere

In this thesis are presented results describing features of zonal-mean dynamics in the middle atmosphere which lie outside the framework described by the "downward control" principle. This principle applies to the nearly steady state wave-driven regime that is approached in the extratropics during solstice seasons. However, it does not apply in the tropics and transience in the extratropics can be significant. One of the assumptions underlying the downward control principle is that local changes in wave drag or diabatic heating do not significantly modify wave drag elsewhere. Force feedbacks are investigated in the particular case of artificial "sponge layers" used in general circulation models. Such relaxational damping is found to couple with changes in forcing or diabatic heating in an unrealistic manner, leading to "upward control". In the tropics there exists the so-called nonlinear Hadley circulation, which is driven by a combination of gradient-wind balance and solar heating gradients rather than wave forcing. Previous work is extended by numerical experiments which support the validity of gradient-wind balance in the tropics. Inertial instability is found to have a potentially large impact on the structure of this circulation. Another purpose of this work is to explain annual mean upwelling in the tropical stratosphere, an important element in the middle atmosphere climate. The inviscid linear view of the diabatic meridional circulation induced by extratropical wave forcing cannot explain the observed mean upwelling. The nonlinear Hadley circulation is found to make a large contribution to upwelling in the tropical upper stratosphere. In the tropical lower stratosphere, upwelling is produced by the wave-driven circulation. A nonlinear mechanism for this is demonstrated by numerical experiments. The dynamical impact of spatio-temporal variation in the radiative damping rate is also investigated. In regions where the damping rate is weak there is increased lag between the evolution of wave forcing and the induced circulation. In such regions the temperature is also more sensitive to even a weak circulation. A time dependence in the radiative damping rate is shown to produce a transient-like signature in the annually averaged dynamical fields, which complicates the interpretation of annual mean anomalies.
Hormonal regulation of seizure activity in the adult rat brain, implications for treatment of temporal lobe epilepsy

Clinical studies suggest that gonadal steroids influence seizure activity, particularly in persons with temporal lobe epilepsy. In turn, limbic seizures may alter reproductive function. We determined the roles of gonadal hormones in altering limbic seizure thresholds and the development of motor seizures, as well as the role of limbic seizures in causing reproductive dysfunction in the adult rat. 'Methods.' Studies used both 'in vivo ' kindling of animals and 'in vitro' kindling of hippocampal slices. 'Results'. (1) Effect of hormones on seizures: In ovariectomized females, estradiol-17ß (E2) significantly lowered amygdala/seizure thresholds, facilitated amygdala and hippocampal kindling, and increased serum corticosterone levels. E2 and corticosterone, either alone or in combination, facilitated kindling. In contrast, progesterone (P4) significantly increased amygdala seizure thresholds and slowed the rate of amygdala and hippocampal kindling. P4 also suppressed stage-5 seizures in approximately 60% of intact kindled females. The anticonvulsant effects Of P4 may be receptor mediated, since treatment of epileptic hippocampal slices for 1 h with P4 and R5020 (a P4 receptor agonist), but not allopregnanolone (the P4 metabolite), significantly decreased epileptiform responses. In male rats, testosterone and its two metabolites, E2 and dihydrotestosterone, all facilitated kindling. Blockade of either androgen or E2 responses in the male significantly slowed kindling rates, as compared to intact controls. (2) Effect of seizures on reproductive function: In female rats, amygdala kindled seizures caused the cessation of estrous cycles, the development of polyfollicular ovaries, and an increase in serum E2 levels. In male rats, amygdala kindled seizures increased serum concentrations of testosterone, prolactin, and E 2, and increased testis, epididymis and pituitary weight. In contrast, generalized seizures in male rats caused a transient hypogonadal state that was restored within 6 weeks of the last seizure. 'Conclusions.' These results suggest that E2 is proconvulsive in both sexes, and that P4 receptor responses in the female are anticonvulsive. Antagonism of E2 mediated effects in the male brain and/or potentiation of progestin effects in either sex may have potential therapeutic value for men and women with temporal lobe epilepsy.
Phenotypic plasticity of Trichogramma minutum Riley (Hymenoptera: trichogrammatidae) and its implications for mass rearing

Phenotypic plasticity of 'Trichogramma minutum' was estimated to understand how and why the quality attributes of parasitoids vary under different environmental conditions. Parasitoid size, longevity and fecundity showed high plasticity when parasitoids were switched from a target host egg (spruce budworm) to a factitious host egg (flour moth). Arrhenotokous and thelytokous 'T. minutum' reared at 15, 20 and 25°C showed higher plasticity for longevity and fecundity in both populations, while emergence and sex ratio were less plastic. Arrhenotokous 'Trichogramma' were 2 to 5 times more plastic for any given trait when compared to thelytokous populations. Variance components demonstrated that rearing host and temperature caused >90% of the observed variation. The results are discussed further in terms of their ecological/evolutionary significance and implications for mass rearing of the parasitoids.
Structure of regenerated synaptic connections of allotransplanted phasic motoneurons on a tonic muscle in crayfish

Crustacean neuromuscular systems are highly defined into phasic and tonic types exemplified by the deep and superficial flexor muscles in the abdomen of the crayfish 'Procambarus clarkii.' The deep phasic muscle is used occasionally and briefly for escape responses while the superficial tonic muscle is used continuously for routine movements and maintaining posture. To assess the relative importance of the motoneuron and the target muscle in determining the synaptic phenotype of regenerating neuromuscular connections, we attempted a mismatch experiment in which the denervated tonic SFM received an allotransplanted phasic flexor nerve. A quantitative study of various structural parameters of these regenerated synapses using serial section electron microscopy revealed that these synapses, on average, possessed two dense bars that were often closely spaced. Mitochondria comprised a relatively small (6%) volume of the terminals. Collectively, these structural features resemble those of native phasic synapses, thereby corroborating the physiological evidence for the regeneration of phasic type synapses. Therefore, the motoneurons and not their target muscle fibers are most influential in specifying the phenotype of regenerated synapses.
Molecular and cellular mechanisms associated with cardiac hypertrophy following myocardial infarction in rats, studies on ion channels and intracellular calcium

Prolongation of the cardiac action potential duration (APD) is a hallmark feature of cardiac hypertrophy. In my studies, I examined the molecular and ionic basis of this electrical phenotype in different anatomical regions of the heart and examined its functional consequence on calcium handling in rats 8 weeks following ligation of the left anterior descending (LAD) coronary artery. LAD ligation resulted in approximately 40% infarction of the left ventricle, a decrease in left ventricular developed pressure, an increase in left ventricular end-diastolic pressure with no evidence of pulmonary congestion, increased wet heart weight to body weight ratios and elevated cellular capacitance. Following myocardial infarction (MI), the density of the transient outward K+ current (Ito) was reduced by about 2 fold in right ventricular myocytes but not septal myocytes. Kv4.2 mRNA and protein and Kv4.3 mRNA were markedly reduced in the right ventricular myocytes but not in septal myocytes, suggesting that reductions in Kv4.2 and Kv4.3 are responsible for the reduced Ito. The recovery from inactivation of Ito was slowed and was associated with an elevation in Kv1.4 mRNA and protein in right ventricular myocytes, but not septal myocytes. Consistent with the changes in I'to' density, changes in APD and Ca 2+ transients following MI varied between the right ventricle and septum. Moreover, the elevations in [Ca2+]i were directly linked to prolongation of action potential duration and were not related to changes in L-type Ca2+ currents or altered calcium handling in post-MI myocytes. Treatment with the thyroid hormone analog, DITPA, for five weeks restored Ito density by reversing Kv4.2 and Kv1.4 expression and abbreviating action potential duration to levels observed in sham-operated controls. Our findings demonstrate that LAD ligation in rats is associated with electrical, ionic and genetic changes that can be reversed by thyroid hormone administration.