VictorJuiz/thesis huggingface dataset:
The design of high-gain slot arrays on electrically thick substrates for millimeter-wave applications

The design of high-gain slot arrays on electrically thick dielectric substrates at millimeter-wave (mm-wave) frequencies is presented in this thesis. The slot arrays are series fed by coplanar waveguide (CPW). The primary focus is on the effective design of the arrays and analysis of the effects of the feeding architecture on the antenna array parameters. The design procedure is based upon an intuitive transmission line model and includes techniques for the reduction of feed-line losses. The loss from coupling to the dominant surface-wave mode is reduced through a phase cancellation technique. Further, the arrays can be made unidirectional with the addition of a backing ground-reflector which employs phase cancellation of the TEM mode that can propagate between the two ground planes. The work is verified through experimental results around a nominal frequency of 27.8GHz and 12.3GHz.
N-cadherin mediated cell-cell adhesion in the arterial wall

During migration, smooth muscle cells (SMC) modulate their interactions with surrounding matrix and cells. The goal of this study was to examine the lateral adhesion N-cadherin complex and how it is modulated as SMCs assume a migratory phenotype during proliferative responses to injury. N-cadherin was found localized at the basolateral extensions of contacting SMCs. Inhibition of N-cadherin complexes with blocking antibodies reduced the ability of SMCs to migrate in vitro. Morphologically, cells had shorter, blunted processes into the wound area that translated into significantly reduced wound edge growth at 24 and 48 hours after wounding. In vivo, western analysis and immunofluoresent staining showed that neointimal SMCs in rat carotid arteries expressed increased levels of N-cadherin, ß-catenin and plakoglobin at 1 and 3 weeks and decreased levels at 8 weeks after balloon catheter injury. These results suggest that cell-cell contact mediated by N-cadherin is involved in the migration of SMCs.
The peer mediation process in secondary schools

The purpose of this study was to investigate the practice and the impact of peer mediation in eight secondary schools. This research is the first to investigate peer mediation in secondary schools. In doing so, it sought to give the peer mediators and other students a "voice." The students explained the peer mediation process, the effects on their personal lives, relationships, school climate and families. The thirty-three participants of the study include eight mediators, two disputants, two non-disputants, six students who refused mediation, seven teachers, one non-teacher and seven administrators. Three students refused to be interviewed. All student participants were eighteen years of age when interviewed. The method employed is qualitative. A personal interview was conducted with each mediator and disputant to investigate what happens during the mediation process, their satisfaction with the process and the impact it is having on them and the school community. Teachers, coordinators of the peer mediation programs and administrators were also interviewed individually to get their perception of the program's impact on the mediators, disputants, other students and the school climate. Data gathered were analysed in four stages. The interviews were transcribed verbatim and the categories and themes were identified and sorted. The findings indicate that peer mediation provides one of the best opportunities for creating peaceful schools. The study is significant because it verifies and brings to the forefront ten issues that are important to the field of peer mediation and conflict resolution. The issues are that: peer mediators can peacefully resolve conflicts and they are exemplary student leaders; peer mediation promotes ethics, transforms lives, teaches lifelong skills, provides leadership, fellowship, growth and provides an alternative to suspension; peers trust their peers to resolve their problems; school violence is on the increase and there is a lack of support for peer mediation. The findings of this study warrant further investigation in three areas: peer mediators and other students who are between 14 and 17 years of age; the training programs; and the real cost to implement a program in a secondary school.
Architecture of the human soleus muscle, three-dimensional computer modelling of cadaveric muscle and ultrasonographic documentation in vivo

The purpose of this study was to visualize and document the architecture of the human soleus muscle throughout its entire volume. The architecture was visualized by creating a three-dimensional manipulatable computer model of an entire cadaveric soleus, 'in situ', using B-spline solids to display muscle fiber bundles that had been serially dissected, pinned and digitized. A database of fiber bundle length and angle of pennation throughout the marginal, posterior and anterior soleus was compiled from three sources: the computer model, manually measured cadaveric specimens and from ultrasonographic scans of relaxed and contracted muscle of living subjects. The computer model allowed documentation of the architectural parameters in three-dimensional space, with the angle of pennation being measured relative to the tangent plane of the point of attachment of a fiber bundle. The architectural parameters recorded to date have been two-dimensional, like those obtained from the scans and manually measured cadaveric specimens in this study. Three-dimensional reconstruction is an exciting innovation since it provides not only an architectural database but also allows visualization of each fiber bundle 'in situ ' from any perspective. It was concluded that the architecture is non-uniform throughout the volume of soleus, the percentage change of the architectural parameters on contraction varies by muscle part and the soleus of females has significantly longer fiber bundles, smaller angles of pennation and is not as thick as the soleus of males. The techniques developed in this thesis provide a novel approach to the study of muscle architecture. Detailed architectural studies may lead to the development of muscle models that can more accurately predict interaction between muscle parts, the effect of pathologic states on muscle function and force generation.
Effect of CO on human chemoreflexes

Despite decades of study, the precise mechanism by which the carotid body transduces the hypoxic stimulus remains controversial. CO inhibits carotid body output; Prabhakar has recently hypothesized that heme oxygenase 2 (HO-2) located in the glomus cells is the oxygen sensor, and that during hypoxia, endogenous CO production by HO-2 decreases, which disinhibits the carotid body. It was hypothesized that human subjects with mild carboxyhemoglobinemia would exhibit a reduced ventilatory response to hypoxia. Ten healthy male volunteers performed iso-oxic rebreathing tests at PO2 of 50 and 150 mmHg before and after inhalation of ~1200 ppm CO in air, resulting in COHb values of 10.2 ± 0.2% (mean ± SEM). No statistically significant differences in threshold or sensitivity were observed due to CO. Mild increases in COHb in healthy humans do not affect chemoreflex sensitivity, suggesting that endogenous CO production may not be important in transducing the hypoxic stimulus.
Analytical methods for multivariate stable probability distributions

Stable probability distributions (SPDs) are generalizations of the familiar Gaussian distribution, but have infinite variance. Thus, statistical techniques relying on finite variance are inapplicable to SPDs. In particular, the correlation structure of multivariate SPDs is much more complex than a Gaussian; it is described by a measure on the sphere, called a 'spectral measure', and is poorly understood. In this work, the relationship between multivariate SPDs and their spectral measures is illuminated, and tools are developed for the statistical analysis of multivariate SPDs. Methods from nonabelian harmonic analysis are applied to express the spectral measure using spherical Fourier series; this leads to an efficient and practical method for estimating spectral measures from empirical data, even in very high dimensions. Formulae are computed which relate the estimation error of a spectral measure back to the estimation error of the original SPD. These results are then applied to the identification and analysis of stable stochastic processes.
Interactive cutting of surface meshes for computer-aided surgical planning

The goal of a computer-aided surgery planning system is to allow surgeons to plan surgical operations in a virtual environment, aided by realistic visual and haptic feedback. In this thesis we develop such a system, building upon commercial medical image analysis software and a versatile haptic input/output device. In our system we have implemented cutting and positioning operations supported by realistic haptic and graphic feedback. We also present algorithms for making template planar cuts and free-hand contour cuts through solid objects represented by triangular surface meshes. Mesh-cutting algorithms are complicated because they require the mesh topology to be changed, and this may introduce degenerate mesh elements. The algorithms we develop introduce approximation and mesh refinement approaches to eliminate mesh degeneracies due to cutting operations, and a sampling technique that yields predictable cut accuracy independent of the mesh structure.
The role of the suprachiasmatic nucleus in temporal gating of performance on a reward-based learning and memory task

In the present experiment, the role of the biological clock in the suprachiasmatic nucleus (SCN) is investigated as a provider of temporal information underlying time dependent changes in cognitive performance. Hamsters were tested on the conditioned place preference task before, and after ablation of the SCN. Animals were conditioned at Zeitgeber time 15 (ZT15), then tested at two different times of day: ZT15 and ZT6. All animals expressed time dependent preference in test phase--they spent significantly greater amount of time in the paired chamber when tested at ZT15 but not when tested at ZT6. This supports the notion that circadian information is an essential component of context representation (Antoniadis et al, 1999). Furthermore, there were no differences in temporal modulation of context preference expression between the experimental and sham groups. An oscillator, outside of the SCN, may be responsible for time discrimination in reward-based learning.
Application of geometric bounds to convergence rates of Markov chains and Markov processes on R[superscript]n

Quantitative geometric rates of convergence for reversible Markov chains are closely related to the spectral gap of the corresponding operator, which is hard to calculate for general state spaces. This thesis describes a geometric argument to give different types of bounds for spectral gaps of Markov chains on bounded subsets of <math> <f> <blkbd>R<sup><mit>n</mit></sup></blkbd></f> </math> and to compare the rates of convergence of different Markov chains. We also extend the discrete-time results to homogeneous continuous-time reversible Markov processes. The limit path bounds and the limit Cheeger's bounds are introduced. Two quantitative examples of 1-dimensional diffusions are studied for the limit Cheeger's bounds and a 'n'-dimensional diffusion is studied for the limit path bounds.
Improving quality of reliability data in a condition-based maintenance system

Condition-Based Maintenance (CBM) system, which is utilized in a preventive maintenance plan, uses reliability data to produce models and decisions for some equipment in an organization. Usually there is a necessity to run the data through a preparation process, before using that for analysis, to obtain an error-free data set. The focus of the present study is on preparation of reliability data required by CBM Optimizer software and to improve the quality of the data submitted by the companies for CBM analysis. The procedure includes mapping, transferring, checking and modification of data. The CBM project is involved with a Maintenance Consortium of Canadian companies including Dofasco, Syncrude, Hydro One and PriceWaterHouseCoopers.
Accuracy of Teacher Assessments of ESL Children At-Risk for Reading Disability

This study examined the accuracy of teacher assessments in screening for reading disabilities among ESL and first language (L1) students. Three hundred and seventy-five children (262 ESL, 113 L1) were administered academic and oral language tests in grades 1 and 2. Concurrently, 48 teachers nominated children at risk for reading failure and completed rating scales assessing academic and oral language skills. Scholastic records were reviewed for teacher notation of concern or referral. The criterion measure for at-risk status was a standardized reading score based on 3 measures: (1) phonological awareness, (2) rate of access of phonological information and (3) word recognition. Results indicated that teacher rating scales and nominations were accurate in screening but the accuracy was considerably lower for ESL compared to L1 students. Relative to other forms of screening, teacher expressed concern in student files had a lower sensitivity. Finally, oral language proficiency was found to contribute to misclassifications.
So few convictions, the role of victim-related characteristics in the legal processing of sexual assault cases

In Canada there has been neither recent nor systematic examination of the relationship of victim-related characteristics and evidentiary factors to the legal resolution of sexual assault cases. This study was designed to document the attrition of sexual assaults and to determine which factors influence legal decision-making. Based on feminist theorizing about rape-tolerant attitudes within the criminal justice system, it was hypothesized that the personal attributes and behaviours of the victim and the interpersonal context of the assault would be related independently of evidentiary factors to whether a case was (a) cleared by an arrest and charge and (b) concluded in conviction. The results of this study revealed substantial attrition for 187 sexual assaults reported to a sexual assault care centre and a metropolitan police service in 1994. A total of 8% of the examined cases were unfounded and 47% were cleared by an arrest and charge. Less than one fifth (17%) resulted in a conviction. Several victim-related characteristics were related to the high rate of attrition. Cases involving older women or women who did not physically resist the offender were less likely to be cleared by a charge. Women who had experienced prior abuse as adults or who were assaulted by a current or a previous partner were less likely to see the assailant convicted. Vaginal, anal and/or foreign object penetration, the completion of a forensic kit and the collection of forensic evidence were necessary for cases to advance to the court level of processing. A charge was predicted by the corroborating evidence of a witness and conviction by the use of physical force. Victim-related variables significant in earlier research studies that did not influence legal resolution in this data set were a victim's ethnocultural, marital and occupational status, a history of mental health difficulties, the use of drugs and alcohol, risk-taking behaviours and the promptness of a report. Nor did a history of child abuse predict a case's disposition. The results of this study suggest that while rape-supportive attitudes may continue to underpin some police, prosecutorial and judicial decision-making, the stereotypical negative views held of rape victims may be changing.
Becoming veterinarians, a relational account of the experiences of ten women

The purpose of this study was to explore the experiences of women who were becoming veterinarians during an era of female dominant student enrollment. Ten women in the Doctor of Veterinary Medicine (D.V.M.) degree program at Ontario Veterinary College (O.V.C.), University of Guelph, between 1989-1997 participated in this qualitative study. Through life history interviews, the women expressed themes related to four social contexts: the family, adolescent school and work, undergraduate university, and professional school. The relational metaphor linking the contexts explored the role of empathy from self-objects in the developmental process. Themes in the family involved parental influence, mother-daughter career similarity, and early relationships with companion animals. Themes in the adolescent years involved gaining strength and competence academically and physically with animals, learning through encounters with practising veterinarians, and developing an image of veterinary medicine as ideal for women. During undergraduate university, the themes were managing developmental issues and transition, managing competition in science culture, and preparing to conform to the cultural and learning demands of the profession. Both unique and familiar gendered trends were evident in the professional college experience. Strengthening experiences occurred in the context of belonging to a community, mentoring relationships, and personal validation. Demotivating experiences related to passive learning, competitive peer relationships, lack of freedom to express competence, lack of voice, and cultural messages that were at odds with combining career and family. This research affirmed previous work that has argued that women prefer connected, relationally-oriented education (Belenky, Clinchy, Goldberger, & Tarule, 1986) and that science education is competitive and non rewarding (Seymour & Hewitt, 1997). This research failed to report a loss of voice during the adolescent years (Brown & Gilligan, 1992); however, loss of voice became increasingly apparent during undergraduate and professional education. Some reports of homophobia, gender discrimination and harassment underscore previous findings (Betz, 1994; Betz & Fitzgerald, 1987) that such experiences are part of women's career development. Veterinary medicine offers a unique example of a profession in which many talented women are moving. Nevertheless, the women in this study were still experiencing contradictions in integrating their worlds of work and family.
Feature-based pose-estimation for robotic fixtureless assembly

The research presented herein is a step toward the realization of a prototype flexible fixtureless assembly workcell. One requirement of a fixtureless workcell is the ability to locate and grasp parts that have been presented in arbitrary poses. The Feature CMAC neural network has been shown to solve the 3-DOF pose-estimation problem based on visual information for simple target parts. Through the use of more advanced feature-extraction algorithms and improved methods of manipulation, the Feature CMAC's capability has been extended for use with an unmodified industrial target part. The RMS positional error was found to be below 1.0 mm, and below 1.2° in orientation. In addition, the necessary tasks for application of the Feature CMAC pose-estimation system to a fixtureless assembly workcell have been identified.
An implementation of a gateway for hierarchically encoded video across ATM and IP networks

In this thesis, we describe an implementation of an application level gateway for connecting adaptive applications using hierarchical encoded video across ATM and IP networks. The gateway participates in RSVP and ATM signaling. The signaling information, as well as local information about processing load, is used by the receivers to decide the number of layers to join, and by the sources to fine tune the bit rates of the layers to the available capacities. Our approach pushes layering related complexity to the edge of the network, and allows us to use standard ATM UNI and RSVP signaling. The gateway participates in a modified session directory (SDR) protocol, to learn the addressing information necessary to perform signaling translation, and to enable layered sessions to be visible across the IP/ATM boundary. We also implement different queue management mechanisms, namely round robin, priority, Random Early Detection and RED with In/Out algorithms, in the gateway and study their impact on the performance of the gateway.
Modelling of iron losses of permanent magnet synchronous motors

This thesis proposes a refined approach to evaluate iron losses of surface-mounted permanent magnet (PM) synchronous motors. PM synchronous motors have higher efficiency than induction machines with the same frame and same power ratings. However, in PM synchronous motors, iron losses form a larger portion of the total losses than in induction machines. Therefore, accurate calculation and minimization of iron losses is of particular importance in the design of PM synchronous motors. Although time-stepped FEM can provide good estimations of iron losses, it requires high effort and is very time-consuming for most designs and particularly for optimizations. Besides, FEM analysis can only be performed after the machine geometrical dimensions have been determined In contrast, approximate analytical loss model yields quick insight while requiring much less computation time and are readily available during the preliminary stage when the motor design is being iterated. Therefore, it is desirable to develop iron loss models that produce an acceptable prediction of the overall iron losses in a relatively simple way and provide machine designers a more reliable method to estimate iron losses in the initial design of PM machines. In this thesis, simplified models for the estimation of tooth and yoke eddy current losses are developed based on the observations of FEM results and analytical analyses of the magnetic fields taking into account detailed geometrical effects. The effectiveness and limitations of the models are investigated. Correction factors are derived for geometrical influences. The nature of the flux density waveform has great impact on iron losses. Therefore, reduction of iron losses can be achieved by properly shaping the magnets, designing the slots and choosing appropriate number of poles. Some guidelines are provided to minimize iron losses of PM synchronous motors. In order to test the proposed simplified loss models, measurements were performed on two surface-mounted PM synchronous motors. Particular attention was focused on the measurement of PWM waveforms and decomposition of no-load losses. Experimental results of the two motors confirmed the validity of the proposed iron loss models.
The direct study of the reaction of the tamoxifen carbocation with DNA

Of the women administered tamoxifen (TAM) to treat breast cancer, a small percentage developed endometrial adenocarcinomas. The mechanism of carcinogenesis involves the formation of a carbocation intermediate (TAM +) that binds to cellular DNA causing frameshift mutations. To examine the binding that leads to the formation of adducts, a detailed study of TAM + in the presence of DNA was conducted. TAM+ was shown, by kinetic measurements, to form non-covalent association complexes with DNA. This electrostatic binding was confirmed by varying pH and ionic strength. Decreasing pH and added salt increased the binding constant and observed rates. The TAM+·DNA complex reacts with water and DNA to form alcohols and adducts respectively. The selectivity ratios (rate of reaction with DNA vs. water) were: by HPLC, 7.31 * 10 3 M-1 and 3.75 * 103 M -1 at 22°C and 37°C respectively; by laser flash photolysis, 2.76 * 104 M-1 and 1.86 * 104 M-1 at 22°C and 37°C respectively. DNA is a better nucleophile than polyguanylic acid or deoxyguanosine alone.