The distribution of particles in the Eastern Pacific Ocean was investigated from 2 January to 14 February, l969, on the YALOC-69 cruise of Oregon State University. The size distributions were well fitted by the two-parameter Weibull distribution function, with a predominant number of them nearly exponential in distributional shape. Although particles smaller in diameter than 1i could not be measured, extrapolation of the Weibull distribution into the small particle range indicated the median particle diameter was smaller than 1μ. Measurements of light scattering were taken simultaneously with the particle size determinations. A linear relationship between the total particulate surface area and the volume scattering function, β(45°) was indicated, as well as between β(45°)/β(135°) and the mean particle diameter of distributions sharing a common shape parameter. Five different characteristic distributional shapes were found which typified all but a few of the distributions. No direct relationship was found between the distributional shapes and the water types encountered on the cruise. The first-order exponential shapes of the size distributions suggest that a detrital decay mechanism of the larger particles (i. e. phytoplankton) could be a dominant factor in determining the small particle end of oceanic particle distributions. / Graduation date: 1970

Thesis (M.Sc.)--York University, 2004. Graduate Programme in Chemistry. / Typescript. Includes bibliographical references (leaves 117-120). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL:http://gateway.proquest.com/openurl?url%5Fver=Z39.88-2004&res%5Fdat=xri:pqdiss&rft%5Fval%5Ffmt=info:ofi/fmt:kev:mtx:dissertation&rft%5Fdat=xri:pqdiss:MQ99407

In this dissertation, a new approach for determining gaze direction is presented. This approach is based on the existence of a visual axes center for the human eye, the location of which is invariant with respect to the head. The vector from the visual axes center of an eye through the pupil center provides a reliable approximation for a gaze vector. Calibration camera images of human subjects looking at known points on a computer monitor are collected in a non-intrusive manner. Algorithms are applied to the images from two independent cameras whose spatial relationship is known with respect to the monitor. The calibration algorithms allow determination of physical distances between selected facial features visible in the images and the invariant location of the visual axes center for each eye (not visible) with respect to these features. Given these invariant relationships between a subject's facial features and eye visual axes centers, optimization techniques are applied to subsequent images collected from a single camera to obtain the three-dimensional locations of the visible facial features and the visual axes centers, and from these, the gaze direction. The results of experiments conducted to determine the viability and accuracy of the visual axes center approach in determining the gaze direction are presented. The results show that the approach can provide acceptable gaze direction error values when high accuracy (< 1° angular error) is not required. Techniques to improve accuracy are discussed as well as potential limitations of the approach.

Medical students enter medical school with varied backgrounds and learning expectations. Tensions arise between medical students’ expectations and expectations of the teachers and program, which impacts motivation. In self-determination theory people are motivated by satisfaction of three psychological needs: autonomy, competence, and relatedness, which enhance self-determination, but when hindered decrease motivation and well-being. The purpose of this study was to explore medical students' perspectives of their self-determination during medical school by exploring medical students’ perspectives of autonomy-supportiveness, competence-supportiveness, and relatedness with their teachers in their medical education program, and the impact on their learning. I used mixed methods design with two phases. In Phase I, medical students from a single institution completed three surveys all derived from self-determination theory, which investigated causality orientation, autonomy-supportiveness of teachers, and motivation to engage in learning. In Phase II, two World Café events were held at two sites. Medical students’ discussed their perspectives of autonomy, competence, and relatedness in their medical education. I used deductive content analysis to organize the findings into themes. In Phase I, 178 students responded (57% female). Survey scores were compared by gender, year in program, years of university before medical school, and distributed program site. The results indicated that medical students were autonomously oriented. Females were more autonomy-oriented than males, and engaged in learning for more autonomous reasons. Students in the distributed site perceived their teachers to be less autonomy supportive. In Phase II, 64 students attended two World Café events. Themes were categorized according to psychological need. The students identified several teacher actions and curricular structures that supported and hindered their self-determination. The themes across distributed sites were consistent; however, students in the distributed site perceived lower autonomy and less relatedness with their teachers. This study used qualitative methods to explore students’ perspectives of self-determination, which is unique to the self-determination literature. Educators often emphasize teaching methods to maximize cognitive and motivational outcomes. However, medical students emphasized specific teacher actions and curricular supports as most important for establishing the motivational context for learning. This research will help medical teachers to intentionally create appropriate motivational contexts for learners.

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This thesis demonstrates that by redefining the notion of nationhood and by treating nations and national minorities equally with respect to self-determination, it is possible to formulate basic principles of the international legal system, which would promote territorial integrity and stability of multinational states better than the existing system. I demonstrate that theories dealing with self-determination based solely on human rights or cases of secession address the problem with inadequate tools. I also show that minority-rights approaches do not accommodate self-determination claims of national groups properly. / I offer a new idea of nationhood as a political culture of self-determination with which people self-identify. It includes beliefs about co-nationals' mutual membership in a political community, which is perceived by them as having a self-determining power. Definitions of nationhood which use the notion of culture, but not political culture, are both too inclusive---they fail to distinguish between national and ethnic groups, and too exclusive---they overlook multicultural nations. / Contested secession has received much attention in recent scholarship. Since, however, contested secession is based upon the disagreement of two or more national groups concerning their self-determination within particular boundaries, I consider secession within the scope of a systematic approach to the regulation of relations among national groups. I propose that international legal principles should be based upon the recognition of states and national groups as the two basic elements of the international system, and the equal recognition of nations as political cultures of self-determination. I interpret self-determination as a claim to equality within the boundaries a multinational state, and formulate a criterion of minimal justice for states. It requires that states respect equality of self-determination of national groups on their territory. National groups can secede from multinational states either by mutual agreement, or if their they are persistently denied a status with respect to self-determination equal to that of other national groups.

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Multiplex polymerase chain reaction (PCR) assays were designed that incorporated primer pairs for the sex determining region on the Y chromosome, Sry, and one or two control sequences. A triplex and a duplex assay were created involving Sry and Dax, a single copy X chromosome gene which is involved in the female sex determination pathway. The third sequence in the triplex assay was a repetitive Y chromosome sequence, YR. A minimum of 2.5 x 10-3 to 2.5 x 10 -4 m g/ m L of male DNA and 2.5 x 10-5 m g/ m L of female DNA was required if a single multiplex PCR was performed. To demonstrate that sex determination of preimplantation porcine embryos is possible, morulae were collected 5 d post insemination from pregnant mare serum gonadotrophin (PMSG)/human chorionic gonadotrophin (hCG)-treated 60--70 kg prepubertal gilts. Embryos were biopsied using a micromanipulator and cells were placed into individual microcentrifuge tubes for further analysis. Embryos were then cultured to the blastocyst stage. A total of 315 embryos were sexed via the PCR assay with a resultant female/male (%) ratio of 73/27. When 94 embryos from heavier gilts (90--100 kg) were sexed in a similar assay, the resultant female/male ratio was 60/40. Attempts were made to correlate these results with karyotypes. Five transfers of sexed embryos into synchronized recipients were attempted. None of these resulted in pregnancies; although return to estrus was delayed by two to eight days, in four out of the five recipients. Our findings suggest that PCR amplification of the Sry gene can be a reliable method for sexing porcine embryos. It does appear that embryo quality is critical for both the PCR assay and subsequent successful culture. (Abstract shortened by UMI.)