VictorJuiz/thesis huggingface dataset:
The complexity of derivations of matrix identities

In this thesis we are concerned with building logical foundations for Linear Algebra, from the perspective of proof complexity. As the cornerstone of our logical theories, we use Berkowitz's parallel algorithm for computing the coefficients of the characteristic polynomial of a matrix. Standard Linear Algebra textbooks use Gaussian Elimination as the main algorithm, but they invariably use the (very infeasible) Lagrange expansion to prove properties of this algorithm. The main contribution of this thesis is a (first) feasible proof of the Cayley-Hamilton Theorem, and related principles of Linear Algebra (namely, the axiomatic definition of the determinant, the cofactor expansion formula, and multiplicativity of the determinant). Furthermore, we show that these principles are equivalent, and the equivalence can be proven feasibly. We also show that a large class of matrix identities, such as:<display-math> <fd> <fl>AB=I[right arrow]BA=I</fl> </fd> </display-math>proposed by S. A. Cook as a candidate for separating Frege and Extended Frege propositional proof systems, all have feasible proofs, and hence polynomially-bounded Extended Frege proofs. We introduce the notion of completeness for these matrix identities. As the main tool to prove our results, we design three logical theories:<display-math> <fd> <fl><rm>LA<hsp sp="0.212"></rm><mit>&sub;</mit><hsp sp="0.212"> <rm>LA<ty>P<hsp sp="0.212"></ty>&sub;<hsp sp="0.212"></rm><hsp sp="0.212"> [for all]<rm>LA<ty>P</ty></rm></fl> </fd> </display-math>LA is a three-sorted quantifier-free theory of Linear Algebra. The three sorts are indices, field elements and matrices. This is a simple theory that allows us to formalize and prove all the basic properties of matrices (roughly the properties that state that the set of matrices is a ring). The theorems of LA have polynomially-bounded Frege proofs. We extend LA to LAP by adding a new function, P, which is intended to denote matrix powering, i.e., P(' n, A') means 'An'. LAP is well suited for formalizing Berkowitz's algorithm, and it is strong enough to prove the equivalence of some fundamental principles of Linear Algebra. The theorems of LAP translate into quasi-polynomially-bounded Frege proofs. We finally extend LAP to [for all]LAP by allowing induction on formulas with [for all] matrix quantifiers. This new theory is strong enough to prove the Cayley-Hamilton Theorem, and hence (by our equivalence) all the major principles of Linear Algebra. The theorems of [for all]LAP translate into polynomially-bounded Extended Frege proofs.
Studies of responsive properties of poly(n-isopropylacrylamide-co-methacrylic acid) nanoparticles for targeted drug delivery

Poly(N-isopropylacrylamide-co-methacrylic acid) P(NIPAm/MAA) nanoparticles were investigated as potential targetable systems for intravenous drug delivery. The responsive properties of P(NIPAm/MAA) nanoparticles have been characterized using dynamic light scattering (DLS) and responsive adhesion techniques. The hydrodynamic diameter of the nanoparticles decreased with increasing temperature of the aqueous medium. Particle size distributions were Gaussian and relatively monodisperse (GSD $<$ 20% of the mean diameter). The volume phase transition temperature, T$\sb{\rm c}$, of the nanoparticles was sensitive to the state of ionization of surface groups. T$\sb{\rm c}$ increased with increasing pH and decreasing ionic strength of the suspending buffers. The particle concentration of nanoparticles per unit volume was calculated by turbidimetry using Mie theory. The surface hydrophobicity of the nanoparticles was evaluated by partitioning of Rose Bengal on particle surfaces, hydrophobic interaction chromatography (HIC), and partitioning of nanoparticles in PEG/Dextran systems. The surface hydrophobicity of the nanoparticles was found to be greater at 40$\sp\circ$C than at 25$\sp\circ$C by each method. The pH dependence of the partitioning of nanoparticles suggested a cross-over from a steric to a charge stabilization mechanism when the temperature was raised above T$\sb{\rm c}$. Conductometric titration of the nanoparticles suggests that the majority of charges are due to carboxylate residues. The zeta-potential of nanoparticles showed significant levels of surface charge that increased with increasing MAA content. Neither opsonized nor unopsonized P(NIPAm/MAA) nanoparticles stimulated the consumption of oxygen by human neutrophils suggesting the absence of phagocytic cell response whereas polystyrene latexes of similar size and surface charge stimulated increased oxygen consumption by the neutrophils.
Effects of primary treatment optimization on energy savings and recovery in conventional activated sludge process

The objective of this research was to investigate the effects of primary treatment optimization on the energy balance of a municipal wastewater treatment process consisting of conventional activated sludge process and anaerobic digestion. For a case study facility (Oakville Southwest WWTP in Oakville, Ontario), using historical plant data in conjunction with sampling, bench scale settling and particle size analysis experiments, alternatives for primary treatment optimization were developed. Biowin® modeling software was used to simulate the operation of the plant for each alternative, and estimate aeration energy use and the potential energy recovery from the digester gas. It was shown that improvements to primary sedimentation tank (PST) efficiency achieved by optimization of process operation resulted in benefits for the overall treatment process. It was estimated that for each 1.0% improvement in PST efficiency, the average oxygen requirement in aeration was reduced by 0.67%, and the net energy gain/recovery for the entire plant was 28.5 MJ/1,000 m3 of treated flow ($0.60/1,000 m3) or 1.8% of the total plant energy use.
The role of the retinoblastoma protein in retinal development

Although 'RB1' was the first tumor suppressor gene identified, its role during retinal development is poorly understood. We first attempted to determine this by performing 'in vivo' misexpression studies in the post-natal rat retina. Retroviral lineage analysis revealed that clone size in pRB-infected eyes was significantly reduced when compared to control eyes. This suggested that pRB has a role in regulating progenitor cell cycle in the developing retina. The results from 'in vivo' misexpression studies also suggested a possible pRB involvement in cell fate determination and/or re-specification, but more experiments must be performed before concluding this. 'In vitro' rescue experiments with the RB-/- retina is the second experimental approach that may help us clarify the role of pRB in retinal development. To this end, we established a retinal culturing protocol wherein development 'in vitro' mimics that ' in vivo', thus laying the groundwork for future rescue experiments in the RB-/- retina. This study presents significant findings that may help us elucidate the role pRB plays during retinal development.
Ojibwe women as adult learners in a teacher education program, towards an understanding of Aboriginal women's experiences of learning and change

Existing literature in adult education pays scant attention to the experience of Aboriginal adult learners, especially those who are women. Further, while more Aboriginal teachers are needed, and the majority of Aboriginal teacher education students are women, almost no research has been conducted with this student population. The purpose of this study is to better understand the experience of Ojibwe women as adult learners in a program of teacher education. The study explored the experience of eight voluntary participants ranging in age from twenty-nine to fifty-one years of age nearing completion of a two year university program in Aboriginal teacher education. Participants' motivations, expectations, characteristics, interaction, experiences in the program, and goals upon completion were examined. A qualitative approach was employed in gathering data. There were four parts to the study: in-depth interviews with participants; follow-up interviews after individuals had received transcripts of the first interview; a demographic questionnaire; and field notes. Interviews, which yielded more than four hundred typed pages, formed the main part of the study. The emergent research design generated findings which were sorted into four main themes: relationships with others as an Aboriginal teacher education student; survival and success as an Aboriginal learner, personal change during the teacher education program; and "I am an Ojibwe woman." Findings were reported primarily in participants' own words and discussed in relation to theories on adult learning, adult development and Aboriginal education. Interpersonal, community and cultural connections were important to all participants and significantly influenced their educational endeavours. Participants demonstrated cultural continuity and a sense of social responsibility in their activities and concerns as teachers-in-preparation. Program features and other factors which supported or hindered participants in completing their program were identified and discussed. The study explored aspects of personal change and raised ethical issues regarding the appropriateness of conducting research in the area of Aboriginal adult development, concluding that a far deeper and broader research effort would be necessary, and one conducted from the perspective of a cultural 'insider' to achieve legitimacy. Conclusions which have implications for research and program planning in Aboriginal education and questions for further investigation were identified.
Flow quality measurement based on stratification of flow in nitrogen gas-water and HFC-134a refrigerant-PAG oil two-phase flow systems

A simple method is proposed and tested to measure the flow quality in a closed two-phase loop based on the use of a relatively large diameter horizontal tube to stratify the two-phase flow. If the total mass flow rate is known, the flow quality can be reliably determined by measuring the gas phase velocity with a hot-wire anemometer and the void fraction in the horizontal tube. On the other hand, if the total mass flow rate is not known, simplified one-dimensional momentum equations can be solved using the measured void fraction and gas velocity to obtain both the total flow rate and flow quality. This measurement principle was tested using nitrogen gas/water flow loop and good agreement was obtained between the measured and actual flow qualities. Tests were also performed using a compressor-driven refrigerant loop, where the presence of a lubricant oil was determined to have a detrimental effect on the determination of thermodynamic quality based on a heat balance.
A dynamic systems analysis of heterogeneous family processes underlying childhood aggression

A number of approaches to subtyping aggressive children were reviewed and it was argued that parsing aggressive children based on whether or not they also exhibit clinically elevated levels of internalizing problems is critical for targeting appropriate interventions. Little research has been conducted on the differences in causal processes that underlie the development of 'pure' externalizing (EXT) versus 'mixed' externalizing and internalizing children (MIXED). The current dissertation was concerned with locating differences between EXT and MIXED children in their family problem-solving patterns. A dynamic systems (DS) framework, an approach well-suited for the study of heterogeneous developmental phenomena, was adopted for the current study. There were two phases to the study, a pilot and a hypothesis-testing phase. Data from both phases were combined in the final stage of the analyses. In total, 33 parents and clinically referred children (ages 8-12 years old) discussed a problem for 4 minutes and then tried to "wrap up" in response to a signal (perturbation). The perturbation was intended to increase the pressure to resolve the conflict. The main hypothesis was that EXT and MIXED dyads' interaction patterns would be distinguished only based on their behavioural reorganization after the perturbation. Interactions were videotaped and coded for affective content. The sequential data were analyzed using a combination of case-sensitive (state space grids and chi-square analyses) and group-based, multivariate techniques (log-linear modeling). As predicted, results revealed differences between the parent-child interactions of EXT and MIXED children based on dyads' behavioural reorganization in response to the perturbation. Differences before and after the perturbation were found for MIXED, but not EXT, dyads' interactions. MIXED dyads shifted from a permissive pattern to a mutually hostile pattern after the perturbation. Specifically, MIXED mothers showed a significant decrease in their tendency to respond to their child's hostility with neutral responses and a significant increase in their tendency to respond with hostility in kind. This real-time trajectory differed from parents of EXT children who showed a permissive pattern throughout the session. Results suggest that there may be unique parent-child interactions related to subtypes of aggressive children. Theoretical and clinical implications were discussed in light of these findings.
Vocal and genetic variation in the sedentary songbird, Hutton's vireo (Vireo huttoni)

Geographic variation in five populations of Hutton's Vireo (Vireo huttoni) is examined through song and genetic analyses. Distance relationships based on levels of syllable sharing among populations separate Pacific coastal subspecies (V.h. insularis and V.h. huttoni) from southwestern interior and Mexican populations (V.h. stephensi, V.h. carolinae, and V.h. mexicanus). Coastal and interior populations are also vocally differentiated such that coastal birds produce shorter songs with higher minimum frequencies than their interior counterparts. Consistent with song results, mitochondrial DNA control region sequences (310 bp of domain I) yield five similar haplotypes, one of which is restricted to interior populations (V.h. stephensi, V.h. carolinae and V.h. mexicanus) and two that are unique to V.h. mexicanus. Levels of vocal and genetic variation support the hypothesis that coastal and interior populations diverged prior to the last glacial maximum (about 18,000 yrs bp (Cicero and Johnson 1992)) whereas subspecies within each group are more recently separated ($<$12,000 yrs bp).
Local rewetting and distortion of paper

Local rewetting may lead to undesirable distortions in the surface of paper. Using an optical surface scanning interferometer and a modified inkjet printer, a technique for the investigation of local distortions was developed. With this technique, tests of various grades of paper were carried out, and the local distortions were quantified as the changes in local surface roughness, skewness, kurtosis, and average surface height. The relationships between local distortions and paper properties are discussed. A model was developed for the prediction of local paper distortion in terms of the change in surface height as a result of local rewetting: <display-math> <fd> <fl><g>D</g>H=k<fr><nu>Ra<sup>W</sup></nu><de><rad><rcd>&parl0; <fr><nu>Tb</nu><de>g</de></fr>&parr0;<g>r</g></rcd></rad></de></fr> </fl> </fd> </display-math> This model takes into account both the amount of water ('W') applied to paper and the relevant paper properties including roughness (' Ra'), fiber-to-fiber bond strength ('Tb'), and sheet density (<math> <f> <g>r</g></f> </math>). Correlations show that the model values agree well with the experimental results.
Property characterization of CVD nickel

Pure Nickel can be deposited from a Carbonyl vapour gas, by using a Chemical Vapour Deposition (CVD) technique, to form a 25 mm thick bulk solid. The CVD nickel can then be stripped from its substrate to produce a nickel shell. With this technique, nickel deposits with excellent dimensional and surface texture reproduction of the substrate can be obtained. This makes CVD nickel shells ideal for use in manufacturing injection molds and other polymer processing molds. Until now, the properties of CVD Nickel have not been accurately characterized. Use of mechanical testing, in combination with in-situ optical microscopy, electron microscopy, and thermal analysis, have been used for the first time to examine the bulk properties of a thick CVD deposit, which can be used structurally in the absence of its substrate. Optical and SEM Micrographs indicate a bi-modal grain size distribution. Large grains have a high aspect ratio, with their longitudinal direction in the growth direction, and are highly oriented. Uniaxial tensile and compressive testing has confirmed anisotropic mechanical behaviour of the material. The elastic response of CVD Nickel is not linear, and the values are significantly lower than Nickel 200. Furthermore, a marked increase in slope and linearity is observed upon secondary load application below the previously applied maximum stress level. CVD Nickel shell material has significantly higher strength than commercially pure cast Nickel 200. These unexpected phenomena are explained in terms of lattice strain, twinning, texture, and mechanical interaction within the unique CVD Nickel crystal structure.
The phenomenon and poetry of the New York Group, discourses, disguises, and liminality

The New York Group is a circle of Ukrainian avant-garde émigré poets, most of whom began to write and publish in the second half of the 1950s in New York City. The purpose of this study is to examine those creative, philosophical and socio-political aspects that justify the existence of the group as a single literary phenomenon in the history of Ukrainian literature. I approach the group's output and activity by focusing on its discursive practices, thematic preferences, and liminal predicaments. In Part One, I introduce the individual poets and situate them against the background of Ukrainian and Western modernisms in order to elucidate the New York Group's general aesthetic orientations. In Part Two, I outline the group's emergence and formation, paying particular attention to the literary discourses underlying the poets' interaction with their predecessors, contemporaries and successors. In Part Three, I present a thematic analysis of the poetry of the New York Group, concentrating mainly on the poets' predilection for the erotic, the Spanish and the ludic. My aim in this part is to point out the multiplicity of signification inherent in these three selected themes. Finally, in Part Four, I discuss the group's creative, assembling and exilic trajectories and argue that the poetic shift from modernist to postmodernist way of representation as well as the poets' exilic condition can best be conceptualized from the angle of the concept of liminality. I employ the theoretical constructs of Michel Foucault, Georges Bataille, Arnold van Gennep and Victor Turner to provide a framework for my analyses of literary politics and the texts themselves. In the conclusion I argue that the poets of the New York Group, despite their liminal émigré status, were able to transcend their periphery by pushing the aesthetic boundaries of Ukrainian literature. The group's overall contribution has been substantial and it cannot be omitted in any serious discussion of twentieth-century Ukrainian poetry.
Nutritional creatine supplementation and blood growth hormone concentrations during aerobic and anaerobic exercise

The purpose of this study was to assess the effects of a 5-day creatine supplementation protocol on the performance and corresponding plasma growth hormone (GH), lactate (LA), and glucose (GL) responses to a supramaximal (125% V¤O2 peak) and submaximal (70% V¤O 2 peak) exercise. These results showed that five days of creatine supplementation (4x5g/day) significantly increased time to exhaustion and maximal accumulated oxygen deficit during the supramaximal exercise with no significant differences in GH, LA and GL levels compared to placebo. No significant differences between creatine and placebo supplementation in performance enhancement or GH, LA and GL responses were found in the submaximal exercise protocol, although there was a tendency towards increased GH levels after creatine supplementation. A linkage between the muscle-enhancing effects of creatine supplementation and growth hormone responses could not be established.
Molecular mechanisms regulating the assembly and secretion of apolipoprotein B in hamster liver and its overproduction in insulin resistant states

Insulin-resistant states are commonly associated with lipoprotein abnormalities that are risk factors for coronary heart disease. Hepatic overproduction of apolipoprotein B (apoB)-containing lipoproteins is the hallmark of metabolic dyslipidemia in insulin resistance. We used Syrian golden hamsters to study the mechanisms of hepatic overproduction of apoB-containing lipoproteins, as their lipoprotein metabolism closely resembles that of humans. Our studies revealed that hamster hepatocytes efficiently assemble and secrete apoB-containing very low density lipoprotein (VLDL) particles. We induced an insulin resistant state in the hamster by fructose feeding and studied the effects of insulin resistance on apoB biogenesis. Cellular stability of apoB was significantly increased in insulin resistant hepatocytes, possibly linked to marked suppression of ER-60, an apoB-associated ER cysteine protease. Furthermore, hepatic mRNA levels, protein mass, and activity of microsomal triglyceride transfer protein (MTP), a key enzyme in assembly of apoB-containing lipoproteins were dramatically increased. Overall, VLDL-apoB overproduction in fructose-fed hamsters appeared to result from enhanced post-translational stability of nascent apoB and an enhanced expression of MTP, leading to facilitated assembly and secretion of VLDL. We also investigated hepatic insulin signaling in the fructose-fed hamster model to examine the potential contribution of attenuated insulin signaling to the observed VLDL overproduction. Reduced tyrosine phosphorylation of insulin receptor (IR), and its substrates, reduced PI 3-kinase activity, and attenuated serine/threonine phosphorylation of Akt/PKB confirmed induction of hepatic insulin resistance. Elevation of protein mass and activity of protein tyrosine phosphatase (PTP)-1B appeared to be partly responsible for induction of hepatic insulin resistance. Chronic exposure of control hepatocytes to high insulin attenuated IR phosphorylation and increased PTP-1B levels, coinciding with marked suppression of ER-60 and apoB oversecretion. Improvements in phosphorylation status of the IR, in vitro by treatment with sodium orthovanadate, or in vivo by rosiglitazone treatment, attenuated secretion of apoB from fructose-fed hamster hepatocytes. In summary, induction of whole body and hepatic insulin resistance in the hamster by fructose-feeding is accompanied by a marked hepatic overproduction of VLDL-apoB. The VLDL-apoB overproduction may arise from interplay between hepatic insulin resistance and changes in several key components of the VLDL assembly and secretion process including MTP and ER-60.