Simple regulatory mechanisms based on the idea of the saturable 'common stomach' can control the regulation of protein foraging and protein allocation in honeybee colonies and colony-level responses to environmental changes. To study the economic benefits of pollen and nectar foraging strategies of honeybees to both plants and honeybees under different environmental conditions, a model was developed and analyzed. Reallocation of the foraging workforce according to the quality and availability of resources (an 'adaptive' strategy used by honeybees) is not only a successful strategy for the bees but also for plants, because intensified pollen foraging after rain periods (when nectar quality is low) compensates a major fraction of the pollination flights lost during the rain. The 'adaptive' strategy performed better than the'fixed' (steady, minimalistic, and non-adaptive foraging without feedback) or the 'proactive' (stockpiling in anticipation of rain) strategies in brood survival and or in nectar/sugar economics. The time pattern of rain periods has profound effect on the supply-and-demand of proteins. A tropical rain pattern leads to a shortage of the influx of pollen and nectar, but it has a less profound impact on brood mortality than a typical continental rainfall pattern. Allocating more bees for pollen foraging has a detrimental effect on the nectar stores, therefore while saving larvae from starvation the 'proactive' strategy could fail to collect enough nectar for surviving winter.

Magister Commercii - MCom / Economists have confidently agreed that the progression of human capital has an important effect on a state's productivity and growth. Moreover, current research proves the importance of educational outcomes throughout history. Therefore, measuring the quality of education throughout periods can test whether or not human literacy rates directly impact the long-run economic growth of a society. South Africa’s current educational system stems from deeply rooted practices instilled in a previously colonised state. A new branch of economics in South Africa's context is economic history, which allows researchers to analyse previous historical events and make inferences regarding practices, laws, and phenomena occurring in the current era.

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This thesis explores the unique history and geography of Polynesians within Utah. In particular, the historic and current migrations of Hawaiians, Samoans, and Tongans to Utah are examined, and the 1980 and 1990 distributions of Polynesians are mapped and analyzed at three scales: in the United States by state, in Utah by county, and in Salt Lake City by census tract.Historically, Polynesia's relationship with Utah has been religious, specifically of conversion to the Church of Jesus Christ of Latter-day Saints followed by migration to Utah. Today, however, things are changing. Nevertheless, Polynesians continue to migrate to Utah primarily for family, religion, education, and employment.Currently (1990), Utah ranks third in the continental United States with 7,181 Polynesians. Per capita, however, Utah ranks first with about 1 Polynesian per 250 persons. Furthermore, of the continental states with relatively large Polynesian populations (California, Washington, Utah, and Texas), Utah ranks second with over 70 percent growth in its Polynesian population from 1980 to 1990. Indeed, although different Polynesian ethnic groups tend to settle in different areas of Utah, Salt Lake City remains the locus of Polynesian immigration to Utah, particularly for Tongans.

Ant Colony Optimization (ACO) uses behaviour observed in real-life ant colonies in order to solve shortest path problems. Short paths are found with the use of pheromones, which allow ants to communicate indirectly. There are numerous pheromone distribution techniques for virtual ant systems and this thesis studies two of the most well known, Elitist and Max-Min. Implementations of Elitist and Max-Min ACO algorithms were tested using instances of the Traveling Salesman Problem (TSP). The performance of the different techniques are compared with respect to runtime, iterations and approximation quality when the optimal solution could not be found. It was found that the Elitist strategy performs better on small TSP instances where the number of possible paths are reduced. However, Max-Min proved to be more reliable and better performing when more paths could be chosen or size of the instances increased. When approximating solutions for large instances, Elitist was able to achieve high quality approximations faster than Max-Min. On the other hand, the overall quality of the approximations were better when Max-Min was studied after a slightly longer runtime, compared to Elitist. / Ant Colony Optimization (ACO) drar lärdom av beteende observerat hos riktiga myror för att lösa kortaste vägen problem. Korta vägar hittas med hjälp av feromoner, som tillåter myror att kommunicera indirekt. Det finns flera tekniker för att distribuera feromoner i virtuella myr-system och denna rapport kommer studera två av de mest kända, Elitist och Max-Min. Implementationer av Elitist och Max-Min ACO algoritmer testades med instanser av Handelsresandeproblemet (TSP). Prestandan hos de olika teknikerna jämförs med avseende på körtid, iterationer och approximeringskvalité när den optimala lösningen inte kunde hittas. Det konstaterades att Elitist strategin fungerar bättre på små TSP instanser där antalet möjliga stigar är begränsade. Däremot visade det sig Max-Min vara bättre och mer pålitlig när instansernas storlek ökades eller när fler stigar kunde väljas. När lösningar approximerades för stora instanser kunde Elitist uppnå approximationer med god kvalité snabbare än Max-Min. Däremot var den generella kvalitén hos approximationerna bättre när Max-Min studerades efter en lite längre körtid, jämfört med Elitist.

Traffic signal control is an effective way to improve the efficiency of traffic networks and reduce users’ delays. Ant Colony Optimization (ACO) is a metaheuristic based on the behavior of ant colonies searching for food. ACO has successfully been used to solve many NP-hard combinatorial optimization problems and its stochastic and decentralized nature fits well with traffic flow networks. This thesis investigates the application of ACO to minimize user delay at traffic intersections. Computer simulation results show that this new approach outperforms conventional fully actuated control under the condition of high traffic demand.

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No description available.

Brucella causes undulant fever in humans and uterine and systemic infection leading to abortions in domestic animals and wild life. For the acquisition of iron in mammalian hosts, species of Brucella are known to produce two siderophores, 2, 3-dihydroxy benzoic acid (2, 3-DHBA) and brucebactin. Inability to synthesize of 2, 3-DHBA affects the ability of pathogen to metabolize erythritol, replicate in trophoblast cells and cause abortion in pregnant ruminant host. The entF gene has been implicated in the unresolved pathway allowing brucebactin biosynthesis in Brucella. The research effort presented in this thesis tries to relate the role of entF in iron acquisition and potential relation with erythritol metabolism by wild type B. abortus 2308. An entF deletion mutant (BAN1) of B. abortus 2308, generated using cre-lox methodology was found to be growth inhibited in iron minimal media compared to wild type strain. Growth inhibition was further enhanced with the addition of an iron chelator or 0.1% erythritol. Compared to wild type strain, no growth inhibition of BAN1 mutant was found in murine J774A.1 macrophages, which suggests that Brucella could acquire iron inside mammalian cells. The entF gene complemented mutant strains of BAN1 (BAN2A and BAN2B) were found to be intermediate in their ability to grow in iron minimal media supplemented with 0.0.05% erythritol, when compared to wild type and BAN1 strain. The results from the present thesis demonstrate that entF gene plays an important role in iron acquisition and erythritol metabolism by B. abortus 2308 under iron limiting conditions. / Master of Science

After the Seven Year's War, the British government decided to keep a large military force in North America. To coordinate these forces, the Crown decided to continue the office of Commander in Chief. The Commander in Chief had broad authority over the military in the American colonies. This authority, however, conflicted sharply with similar prerogatives granted to royal governors. With neither side willing to surrender any of their power or authority, a series of battles broke out over the supremacy of the army in almost every colony where royal troops were stationed. West Florida, a British colony established after the Seven Years War from captured French and Spanish Territory, provides an excellent example of how the civil-military conflicts could cripple royal government in a colony. Many historians have failed to assess adequately the impact these disputes had on colonial government in America. The purpose of this thesis is to show that the civil-military disputes disrupted colonial governments, and was one of the forces that led to the breakdown of British rule in North America during the 1760’s and 1770’s. / M.A.