1. Plant quality (bottom-up effects) and natural enemies (top-down effects) affect herbivore performance. Furthermore, plant quality can also influence the impact of natural enemies. 2. Lower plant quality through reduced irrigation increased the abundance of the cryptic species from the Bemisia tabaci complex [hereafter B. tabaci Middle East Asia Minor 1 (MEAM1)], but not its natural enemies on cotton. It was therefore predicted that lower plant quality would diminish the impact of natural enemies in regulating this herbivore. 3. Over three cotton seasons, plant quality was manipulated via differential irrigation and natural enemy abundance with insecticides. Life tables were used to evaluate the impact of these factors on mortality of immature B. tabaci (MEAM1) over nine generations. 4. Mortality of B. tabaci (MEAM1) was consistently affected by natural enemies but not by plant quality. This pattern was driven by high levels of sucking predation, which was the primary (key) factor associated with changes in immature mortality across all irrigation and natural enemy treatments. Dislodgement (chewing predation and weather) and parasitism contributed as key factors in some cases. Analyses also showed that elimination of sucking predation and dislodgement would have the greatest effect on overall mortality. 5. The top-down effects of natural enemies had dominant effects on populations of B. tabaci (MEAM1) relative to the bottom-up effects of plant quality. Effects were primarily due to native generalist arthropod predators and not more host-specific aphelinid parasitoids. The findings of this study demonstrate the important role of arthropod predators in population suppression and validate the importance of conservation biological control in this system for effective pest control.

Les recherches menées par le travail de thèse visent à proposer une nouvelle architecture multi-agent pour la conception d’applications sur de nouvelles plateformes de communication telles que les tables interactives. Les systèmes Multi-Agents sont utilisés depuis de nombreuses années et peuvent répondre aux problématiques de telles plateformes. Dans notre contexte, nous avons défini les interactions et les comportements d’agents hétérogènes (virtuels et tangibles), qui évoluent simultanément sur une même surface interactive.Nous avons défini une typologie des agents, utilisés dans le cadre de plateformes interactives, en fonction d’un ensemble de critères permettant d’analyser les caractéristiques logicielles et technologiques (système de capture, affichage, etc.) employées sur ces nouveaux supports. Nous proposons de modéliser les comportements élémentaires nécessaires à la description du problème (interactions éventuelles de plusieurs utilisateurs, utilisation d’objets, visualisation de l’environnement et des agents simulés, traitement des messageséchangés, etc.), lesquels sont représentés par des rôles joués simultanément par un ou plusieurs agents selon un ensemble de prérequis. La réflexion proposée a conduit à la construction d’une architecture multi-agent, laquelle a été appliquée sur la table interactive TangiSense (intégrant une technologie RFID). Nous illustrons et nous validons notre propos à l’aide d’une application, un simulateur de trafic routier. / Research done in this thesis aims to propose a new multiagent architecture to design applications for the new communication platforms like the interactive tables. Multiagent systems are used for many years and can respond to the challenges of such platforms. The motivation of our work is to manage the interactions and the behavior of several heterogeneous entities (virtual and tangible) evolving simultaneously on a single interactive surface. We caracterized the agents typology and their interactions for interactive platforms.We consider a set of criteria to analyze software and technological (e.g. capture system, display, etc.) characteristics used on these new platforms. We proposed to modelize basic behaviors needed to describe the problem (potential interactions between multiple users, tangible objects use, visualization of the environment and simulated agents, treatment of exchanged messages, etc.), which are represented by roles played simultaneously by one or several agents according to a set of prerequisites. With these elements, we propose to apply our multiagent architecture on the interactive table TangiSense (equipped with RFID technology). We illustrate and validate our purpose with an application, a traffic simulator.

Thesis (Nucl.E.)--Massachusetts Institute of Technology, Dept. of Nuclear Engineering, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND SCIENCE. / Includes bibliographical references. / by Kord S. Smith. / Nucl.E.

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The decathlon is a two-day competition of ten events, each event awarded points based on performance. The purpose of this study is to compare sub-national class decathlon scores and event performances with national and elite class decathlon performances and scores. The 2002 United States all-time decathlon performances and the 2002 world all-time decathlon performances were separated into elite, national or sub-national classes according to total points scored. Event performances, event scores, and total scores were then compared. Results indicated that the sub-national class decathletes on average scored less points in every event, showed more variability in performance, had weaker correlations between events and total score, and required more events to predict final score than national and elite decathletes.

Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Beneficiation of thermal coal in India is a relatively new development. For the year 2006, India produced 380 million metric tons of thermal coal, of which only 17 million metric tons were beneficiated coals. One potentially attractive method for upgrading India's coal feed stocks is the air table dry deshaling technology. Dry deshaling offers significant advantages over wet cleaning operations, including reduced surface moisture, enhanced heating value, elimination of processing water and waste slurries, and reduced transportation of large amounts of ash-forming minerals. To evaluate this potential, a pilot-scale air table deshaling unit was tested at three locations in India for the specific purpose of upgrading thermal coals. The field testing confirmed that the separation performance for Indian coals is similar to that which has been achieved at sites in the United States for material in the 50 x 6 mm size range. The data indicate that material with 80% ash and higher can be rejected by the dry deshaler unit with a combustible recovery of more than 90%. Furthermore, a discreet elemental model was developed using PFC3D to understand the process of segregation on a dry density based vibratory table. Analysis was done to show the effect of different forces on the process efficiency. Also, operating parameters and particle properties such as frequency of vibrations, amplitude of velocity, bed depth, particle size and specific gravity were analyzed in the model. The model results were compared with field testing results of dry deshaling air table and All-Air Jig separator. / Master of Science

In this episode, we introduce one of the most important tools in the description of logic operations: the truth table. Not only do truth tables allow us to describe a logic operation, they provide a means for us to prove logical equivalence.

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