Split and normal gate A1GaAs /GaAs MODFETs were fabricated along with the ohmic test structures and the Hall bar geometries. The DC characteristics of normal gate transistors were evaluated at room temperature and at 77K and the threshold voltages were extracted from the measurements and compared to the theoretical results. The performance of normal gate transistors was reasonable. The sheet carrier density and the mobility extracted from Hall measurements using the Hall bar geometry showed increase of carrier density with increasing gate voltage and an increase of mobility with increasing carrier density. The contact resistance obtained from the ohmic test structure was high and not uniform within the sample. / Graduation date: 1991

The plant hormone auxin regulates many aspects of plant growth and development. At the cellular level, auxin can stimulate cell division, cell elongation, and cell differentiation. Little is known about the molecular mechanisms that mediate auxin action at this level, although changes in gene expression have been implicated in each of them. An important step in elucidating the signal transduction steps involved in these responses is the identification of intermediates that respond to auxin treatment within a physiologically relevant range, and can be functionally linked to specific response(s). The Aux/IAA family of auxin-regulated genes, which has been identified in several species, may constitute such a group of signalling intermediates. This dissertation reports on the isolation and characterization of eleven tomato genes, LeIAA1 - 11, which are homologous to these Aux/IAA genes. Expression characteristics in response to exogenously-applied auxin were determined in segments of etiolated hypocotyls. The LeIAA genes fell into three kinetic classes and displayed differential responsiveness to the treatment. Comparison of auxin-induced expression in wild-type and the auxin-insensitive diageotropica (dgt) mutant revealed that induction of only a subset of genes was affected by the mutation while the other genes retained wild-type response levels in the mutant. This finding indicates that at least two signal transduction chains lead to auxin-induced gene expression, and the dgt gene product acts on only one of them. The expression pattern of nine LeIAA genes was determined in a wide variety of tissue samples in order to link individual LeIAA genes with specific physiological responses. To that end, a qualitative multiplex RT-PCR method was developed that allowed quick assessment of relative expression levels in a large number of small RNA samples. It was found that LeIAA10 expression was highest in tissues undergoing rapid growth, suggesting a role for this gene in the process of cell expansion. The expression of LeIAA1 1 was also variable during development, while LeIAA2 was strongly down-regulated after light treatment. These experiments demonstrated organ-preferential expression of LeIAA genes under the control of environmental factors and depending on developmental stages. The LeIAA genes may thus act as integrators of several other signals with the auxin stimulus. / Graduation date: 1998

Graduation date: 1992

This study describes how changes made to the modification of a polyolefin affect the solution properties of these modified polyolefins in apolar solvents. The modified polyolefins of interest are maleated ethylene-propylene random copolymers (EP-MAH) reacted with N-phenyl-p-phenylenediamine (NP3D) to yield NP3D-EP-MAH. NP3D-EP-MAH is used as a dispersant by the oil-additive industry and solution properties such as self-aggregation, rheological behaviour, and its efficiency at stabilizing carbon black particles (CBPs) were investigated. The maleation of the polyolefin was characterized in terms of succinic anhydride (SAH) content and level of SAH clustering along the polymer backbone by FT-IR and UV-Vis absorption and steady-state and time-resolved fluorescence. The self-aggregation of the modified polyolefins was characterized in hexane by replacing NP3D with 1-pyrenemethylamine and using fluorescence to probe excimer formation between an excited and a ground-state pyrene. The rheological behaviour exhibited by the solutions of modified polyolefins was characterized from the viscosity profiles of the solutions obtained as a function of polymer concentration. Finally, the adsorption of the modified polyolefins onto CBPs was characterized by analysis of Langmuir isotherms, which yields both the equilibrium constant and the maximum coverage for the binding of the modified polyolefins onto CBPs. The conclusions reached in this thesis are that clustering of the SAH pendants along the EP backbone enhances the ability of the modified polyolefin to self-aggregate in apolar solution. In turn, self-aggregation led to enhanced thickening of the NP3D-EP-MAH solutions and stronger adsorption onto CBPs. This thesis establishes how the level of SAH clustering affects self-association and establishes its consequence on the rheological properties and adsorption isotherms of NP3D-EP-MAH samples in apolar solvents.

No description available.

The objective of this thesis is to evaluate the influence that the pattern of affiliate linkages- establishments associated with companies as affiliates, subsidiaries and divisions- between U.S. states and Canadian provinces has on the effect of the border on trade between the two countries. The gravity model is used to estimate the border effect. Two hypotheses are tested – that the border effect is greater in the presence of affiliate linkages and that the strength of the border effect varies between industrial sectors. The results support the first hypothesis indicating that when all sectors combined, the presence of affiliates has a positive impact and it significantly strengthens the Canada-U.S. border effect. However, for the second hypothesis, nine sectors analyzed in this study present mixed results. For six sectors of agricultural, mineral, chemical, plastic, machinery and motor vehicle the border effect is not significantly different in the presence and absence of affiliates, while for the other three sectors of wood, textile, and base metals, the impact of affiliates has been significant. However, for wood and base metals sectors border effect has become stronger and for textile it has become weaker in the presence of affiliates. This research shows how the complicated relationship between trade and foreign direct investment determines firms operating in various sectors make decisions between export and establishing affiliates. The implication of the results can shed light on the study of the border effect and trade policy.

Syftet med denna studie var att undersöka huruvida fysisk aktivitet kan påverka en individs frukostval. Vidare undersöktes på vilket sätt frukostvalet i så fall hade påverkats samt om denna förändring var beroende av ålder och kön. Studien var av empirisk, deskriptiv design. Semistrukturerade intervjuer genomfördes med totalt 98 deltagare, 50 kvinnor och 48 män (16-75 år). Enligt resultatet var den kombinerade träningsformen (konditionsträning och styrketräning) den dominerande bland båda könen. Renodlad styrketräning var vanligare bland männen då ingen av kvinnorna uppgav denna som utpräglad träningsform. Kvinnorna utövade istället konditionsträning i större utsträckning än männen. Resultatet visade även att det skilde sig ytterst lite mellan de deltagare som menade att frukostvalet hade påverkats av träning och de som inte upplevt någon förändring. Bland kvinnorna svarade ett fåtal fler att frukosten hade påverkats medan männens svar var jämnt fördelade mellan påverkad och icke påverkad. Åldersmässigt visade resultatet en tydlig skillnad där majoriteten av dem som svarat att frukostvalet förändrats, återfanns i de två yngsta åldersgrupperna, hos båda könen. I den äldsta åldersgruppen var det ingen deltagare som angav att träningen påverkat frukostvalet. Vanliga orsaker till förändring av frukostvalet visade sig vara ökad hunger, en vilja att tillföra kroppen energi för att orka prestera på träningen, att kunna få bästa möjliga resultat av träningen samt för att skapa en hälsosam livsstil. / The purpose of this study was to investigate if regular physical activity can affect a person’s nutritional habits, which in this study focused on breakfast. The study also examined in what way the breakfast habits had been changed and if the change was dependent on sex and age. The study was of empirical, descriptive design. Semi-structured interviews were conducted with a total of 98 participants, 50 women and 48 men (16-75 years old). According to the results, the combined fitness regime (cardio-vascular exercise and resistance training) was dominant among both sexes. Pure resistance training was more common among men while women practiced cardio-vascular exercise more frequently. Further, the result showed very little difference between the participants who said that breakfast habits had changed due to exercise and those who did not experience any change at all. A few more women answered that breakfast habits had been affected compared to the men where the answers were equally divided between being affected and not. The majority of those who reported altered breakfast habits were found in the two youngest groups, among both sexes. In the oldest group no one reported that exercise had affected their breakfast habits. Common causes for change of breakfast habits proved to be increased appetite, to provide the body with enough energy to perform, to get the best result from training and to create a healthy lifestyle.

The objective of this thesis is to evaluate the influence that the pattern of affiliate linkages- establishments associated with companies as affiliates, subsidiaries and divisions- between U.S. states and Canadian provinces has on the effect of the border on trade between the two countries. The gravity model is used to estimate the border effect. Two hypotheses are tested – that the border effect is greater in the presence of affiliate linkages and that the strength of the border effect varies between industrial sectors. The results support the first hypothesis indicating that when all sectors combined, the presence of affiliates has a positive impact and it significantly strengthens the Canada-U.S. border effect. However, for the second hypothesis, nine sectors analyzed in this study present mixed results. For six sectors of agricultural, mineral, chemical, plastic, machinery and motor vehicle the border effect is not significantly different in the presence and absence of affiliates, while for the other three sectors of wood, textile, and base metals, the impact of affiliates has been significant. However, for wood and base metals sectors border effect has become stronger and for textile it has become weaker in the presence of affiliates. This research shows how the complicated relationship between trade and foreign direct investment determines firms operating in various sectors make decisions between export and establishing affiliates. The implication of the results can shed light on the study of the border effect and trade policy.

The purpose of this study was to describe and understand positive middle-years teacher-student relationships and their effects on students in order to ascertain if the studys data would be consistent with the studys conceptual framework. The following three research questions provided the direction for this study:<p> 1. In what ways do middle-years teachers create positive teacher-student relationships?<p> 2. What are middle-years teachers understandings of the effects of positive teacher-student relationships?<p> 3. What are middle-years teachers understandings of why positive teacher-student relationships are important?<p> A conceptual framework was developed to guide this study, which outlined the characteristics of positive teacher-student relationships as: having high expectations, networking with parents, creating dialogue with students, practicing social skills, practicing appropriate self-disclosure, and using rituals and traditions in the classroom (Griffin, 1998). Five effects of positive teacher-student relationships on students were identified: improved self-concept, improved motivation to learn, increased desire for others well-being, increased feeling of security and attachment, and increased desire to improve society (Epp, 1995).<p> Qualitative research was used in this study. Using semi-structured interviews, data were collected from a purposeful sample of five middle-years teachers. Mayans (2001) latent content analysis was the process used in analyzing the research data in this study. <p> The teachers in this study indicated there were five ways they created positive teacher-student relationships: through classroom management and discipline of their students, by having high expectations for their students behaviour and academics, by communicating with both students and their parents, by being positive with students, and through spending time with their students outside of the classroom. The participants indicated positive teacher-student relationships had effects on both students and the school. The interviewees found the effects of positive teacher-student relationships on students were: having a sense of belonging and being motivated to learn. The teachers noted the effects of positive teacher-student relationships on the school were: a decrease in student misbehavior and a safe school environment. The studys participants found teacher-student relationships were important, because of the positive effects on students and the school. Examining these and other findings could provide teachers, administrators, and researchers with some understanding of positive teacher-student relationships and their effects on students and the school. Hopefully, this understanding of positive teacher-student relationships could help middle-years teachers to develop positive relationships with their students, thereby providing students with a sense of belonging, improving students motivation to learn, decreasing student misbehavior, and improving the school environment.

No description available.