Thesis (M.S.P.H.)--University of Michigan, 1939.

Les dinoflagellés epi-benthiques Gambierdiscus et Fukuyoa produisent les ciguatoxines (CTXs) et les maïtotoxines (MTXs), qui sont parmi les toxines marines les plus puissantes connues. Les CTXs sont bioaccumulées et bio-transformées le long de la chaîne alimentaire marine et provoquent la ciguatéra, l'intoxication alimentaire non bactérienne la plus commune au monde. Récemment, la ciguatéra a été rapporté dans des zones non endémiques, notamment les îles Canaries, et un grand nombre d'espèces a été découvert au sein de ces genres. Peu de données sont disponibles sur la toxicité relative entre les différentes espèces et sur les congénères de toxines produits par ces dinoflagellés, en particulier par des souches en dehors de l'océan Pacifique. Plusieurs souches de Gambierdiscus et Fukuyoa ont été examinées pour leur cigua- et maïto-toxicité via les tests neuro-2a et hémolytique, respectivement. G. excentricus a montré une forte toxicité et deux souches des îles Canaries ont été sélectionnées pour la purification des toxines via une approche de fractionnement bioguidé. L'analyse non-ciblée de spectrométrie de masse (SM) à haute résolution a permis la découverte d'un nouveau congénère de MTX, la maïtotoxine-4 (MTX4). La SM à basse résolution de plusieurs souches de Gambierdiscus et Fukuyoa n’a révélé la présence de MTX4 que dans G. excentricus, y compris des souches provenant des îles Canaries, du Brésil et du Golfe du Mexique. La MTX4 pourrait donc servir de biomarqueur pour l’espèce hautement toxique G. excentricus. Les travaux futurs porteront sur l'isolement et l'élucidation de la structure de la MTX4 et l'identification des congénères de CTX produits par G. excentricus. / The epi-benthic dinoflagellates Gambierdiscus and Fukuyoa produce ciguatoxins (CTXs) and maitotoxins (MTXs), which are among the most potent marine toxins known. CTXs are bio-accumulated and bio-transformed along the marine food chain and cause Ciguatera Fish Poisoning (CFP), the most common non-bacterial foodborne intoxication worldwide. Recently, CFP has been reported from areas previously not considered endemic, namely the Canary Islands, and an increasing number of species has been discovered in these genera. Little is known about the relative toxicity between different species and the toxin congeners produced by these dinoflagellates, especially by strains outside the Pacific Ocean. Several strains of Gambierdiscus and Fukuyoa were screened for their cigua- and maito-toxicity using neuro-2a and hemolytic assays, respectively. G. excentricus showed particularly high toxicity and two strains from Canary Islands were selected for toxin purification using a bioguided fractionation approach. Non-targeted high resolution mass spectrometry (MS) analysis permitted the discovery of a novel MTX congener, maitotoxin-4 (MTX4). Targeted low resolution MS analysis of more than 40 strains of Gambierdiscus and Fukuyoa revealed the presence of MTX4 in G. excentricus only, including strains from the Canaries, the South Western Atlantic (Brazil) and the North Western Atlantic (Gulf of Mexico). As MTX4 was not detected in any other species examined, MTX4 may serve as a biomarker for the highly toxic G. excentricus. Future work will include isolation and structural elucidation of MTX4 and identification of CTX congeners produced by G. excentricus.

M.A. (Industrial Psychology) / In reviewing current literature on the evaluation of people, it is clear that the effect of test anxiety accompanying the evaluation process may be detrimental to the individual's performance. In fact, this under achievement of apprentices doing trade tests have significant financial implications for both the individual and the organization concerned. Accordingly, to counteract this adverse effect, it has been recommended that the technique "Stress Inoculation Training" (SIT) be implemented - the end result being an improvement in the individuals' performance. Theoretical persepectives and alternative conceptual understandings of test anxiety are reviewed. In this respect an important development in the field of test anxiety treatment is research dealing with the reinforcement of the individual's ability to cope with stressful and problematic situations, for when test anxiety is reduced the person experiences a corresponding increase in self-efficacy. Self-efficacy plays an important role in a person's belief that he or she can perform to achieve a desired result. In addition, a high degree of self-efficacy has a strong motivational effect. It is suggested therefore, that learning experiences be so designed as to improve self-efficacy, perseverance and performance. This performance can be achieved by the skills taught in SIT. It is also stressed that SIT is a comprehensive approach for the control of stress-related problems.

Los avances psicológicos en las últimas décadas han aportado al desarrollo del modelo positivo de la salud mental de nuestro país, puesto que han confrontado las necesidades de las poblaciones que las demandaron, tal es el caso de los profesionales militares que en cumplimiento de sus labores de alto riesgo activa y directamente en la lucha frontal contra los elementos narcoterroristas hicieron posible el logro de sus objetivos durante sus operaciones militares; por lo tanto, en respuesta a esta problemática, se han establecido estrategias de defensa, incorporando programas de entrenamiento de resiliencia. Por lo expuesto, en la presente investigación pretendemos determinar la influencia de la aplicación de un programa de intervención de resiliencia del personal militar, que integraron unidades operativas de una Institución Armada del Perú, desplegadas en zonas de emergencia. Esta investigación utilizó una metodología de diseño experimental, de tipo longitudinal, con una muestra conformada por 261 de una población de 2088 personal militar, teniendo a 70 en el grupo experimental y 191 participantes en el grupo de control, aplicando el test de resiliencia en dos tiempos, de entrada y salida, para la medición de efectividad del referido Programa, cuyos resultados se presentaron el respectivo análisis, sustentando su influencia positiva, evidenciándose mejoras en el referido personal, en aspectos como su instropección, independencia, interacción, creatividad, moralidad y sentido del humor; así como se recomendó replicar la investigación teórica-práctica a muestras de diferente contexto sociocultural, de mayor tamaño y de diversas áreas de trabajo que ratifiquen la eficiencia del referido programa.

Los avances psicológicos en las últimas décadas han aportado al desarrollo del modelo positivo de la salud mental de nuestro país, puesto que han confrontado las necesidades de las poblaciones que las demandaron, tal es el caso de los profesionales militares que en cumplimiento de sus labores de alto riesgo activa y directamente en la lucha frontal contra los elementos narcoterroristas hicieron posible el logro de sus objetivos durante sus operaciones militares; por lo tanto, en respuesta a esta problemática, se han establecido estrategias de defensa, incorporando programas de entrenamiento de resiliencia. Por lo expuesto, en la presente investigación pretendemos determinar la influencia de la aplicación de un programa de intervención de resiliencia del personal militar, que integraron unidades operativas de una Institución Armada del Perú, desplegadas en zonas de emergencia. Esta investigación utilizó una metodología de diseño experimental, de tipo longitudinal, con una muestra conformada por 261 de una población de 2088 personal militar, teniendo a 70 en el grupo experimental y 191 participantes en el grupo de control, aplicando el test de resiliencia en dos tiempos, de entrada y salida, para la medición de efectividad del referido Programa, cuyos resultados se presentaron el respectivo análisis, sustentando su influencia positiva, evidenciándose mejoras en el referido personal, en aspectos como su instropección, independencia, interacción, creatividad, moralidad y sentido del humor; así como se recomendó replicar la investigación teórica-práctica a muestras de diferente contexto sociocultural, de mayor tamaño y de diversas áreas de trabajo que ratifiquen la eficiencia del referido programa.

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Yes / This paper introduces the concept of user validity and provides a new perspective on the validity of interpretations from tests. Test interpretation is based on outputs such as test scores, profiles, reports, spread-sheets of multiple candidates’ scores, etc. The user validity perspective focuses on the interpretations a test user makes given the purpose of the test and the information provided in the test output. This innovative perspective focuses on how user validity can be extended to content, criterion and to some extent construct-related validity. It provides a basis for researching the validity of interpretations and an improved understanding of the appropriateness of different approaches to score interpretation, as well as how to design test outputs and assessments which are pragmatic and optimal.

Scheduling is one of the most important issues in the planning of manufacturing systems. This research focuses on solving the test scheduling problem which arises in semiconductor manufacturing environment. Semiconductor wafer devices undergo a series of test processes conducted on computer-controlled test stations at various temperatures. A test process consists of both setup operations and processing operations on the test stations. The test operations occur in a specified order on the wafer devices, resulting in precedence constraints for the schedule. Furthermore, the assignment of the wafer devices to test stations and the sequence in which they are processed affects the time required to finish the test operations, resulting in sequence dependent setup times. The goal of this research is to develop a realistic model of the semiconductor wafer test scheduling problem and provide heuristics for scheduling the precedence constrained test operations with sequence dependent setup times. A mathematical model is presented and two heuristics are developed to solve the scheduling problem with the objective of minimizing the makespan required to test all wafer devices on a set of test stations. The heuristic approaches generate a sorted list of wafer devices as a dispatching sequence and then schedule the wafer lots on test stations in order of appearance on the list. An experimental analysis and two case studies are presented to validate the proposed solution approaches. In the two case studies, the heuristics are applied to actual data from a semiconductor manufacturing facility. The results of the heuristic approaches are compared to the actual schedule executed in the manufacturing facility. For both the case studies, the proposed solution approaches decreased the makespan by 23-45% compared to the makespan of actual schedule executed in the manufacturing facility. The solution approach developed in this research can be integrated with the planning software of a semiconductor manufacturing facility to improve productivity. / Master of Science

Over the last decade, U.S. crop prices have become significantly more volatile. Volatile markets pose increased risks for the agricultural market participants and create a need for reliable price forecasts. Research discussed in this paper aims to find different approaches to forecast crop cash prices based on the prices of related futures contracts. Corn, soybeans, soft red winter wheat, and cotton are the focus of this research. Since price data for these commodities is non-stationary, this paper used two approaches to solve this problem. The first approach is to forecast the difference in prices between current and future period and the second is to use the regimes. This paper considers the five-year moving average approach as the benchmark when comparing these approaches. This research evaluated model performance using R-squared, mean errors, root mean squared errors, the modified Diebold-Mariano test, and the encompassing test. The results show that both the difference model and the regime model render better performance than the benchmark in most cases, but without a significant difference between each other. Based on these findings, the regime model was used to make forecasts of the cash prices of corn and soybeans, the difference model was used to make predictions for cotton, and the benchmark was used to forecast the SRW cash price. / Master of Science