Background: Despite progress made in the last decades, malaria persists as a pressing health issue in sub-Saharan Africa. Pregnant women are particularly vulnerable to infection and serious health outcomes for themselves and their unborn child. Risk can be mitigated through appropriate use of control measures such as insecticide-treated bed nets. Although social networks can influence uptake of preventive strategies, the role of social influence on bed net ownership has not been explored. During an evaluation of a bed net distribution programme, the influence of non-health care advisors on ownership and use of bed nets by pregnant women in Kumasi, Ghana was examined. Methods: Data were collected through in-person interviews with 300 pregnant women seeking antenatal care in an urban hospital in Kumasi, Ghana. Participants were asked about their bed net ownership, bed net use, and information about three personal contacts that they go to for pregnancy advice. Information about these advisors was combined into an influence score. Logistic regression models were used to determine the association between the score and bed net ownership. Those who owned a bed net were further assessed to determine if interpersonal influence was associated with self-reported sleeping under the bed net the previous night. Results: Of the 294 women in the analysis, 229 (78%) reported owning bed nets. Of these bed net owners, 139 (61%) reported using a bed net the previous night. A dose response relationship was observed between the interpersonal influence score and bed net ownership and use. Compared to the lowest influence score, those with the highest influence score (> 1 SD above the mean) were marginally more likely to own a bed net [OR = 2.37, 95% CI (0.87, 6.39)] and much more likely to use their bed net [5.38, 95% CI (1.89, 15.25)] after adjusting for other factors. Conclusions: Interpersonal influence appears to have modest impact on ownership and use of bed nets by pregnant women in an urban area of Ghana. Further investigations would need to be conducted to determine if the relationship is causal or if individuals who associate are simply more likely to have similar practices.

BACKGROUND: Schizophrenia is a debilitating disorder that has a profound impact on quality of life due to the presence of both cognitive deficits and psychotic symptoms. Despite having significant global economic and social costs and a worldwide prevalence of 1%, schizophrenia is still not well understood. Research has been making strides in uncovering the pathophysiology and the etiology that drive this disease, ranging from genetic abnormalities, disrupted circuitry, changes in microarchitecture, to impaired synaptic connectivity. Evidence suggests that disrupted-in-schizophrenia-1 (DISC1) driven genetic disturbances in fast-spiking parvalbumin (PV) neurons and their surrounding perineuronal nets (PNNs) likely contribute to schizophrenia etiology as they are part of the microcircuits required for working memory, a cognitive function that has been consistently impaired in schizophrenic patients. OBJECTIVE: To identify the neuroanatomical changes in PV neurons and surrounding PNNs in the superficial and deep layers of the prelimbic and infralimbic prefrontal cortex of a rat DISC-1 knockout model. METHODS: 19 DISC1-KO male rats and 15 wildtype rats were treated with saline or MK-801. They were sacrificed between P268-269 and brains were extracted and separated at the corpus callosum. After fixing and preserving, the brains were sliced then stained to visualize parvalbumin and perineuronal nets with immunohistochemistry. Slices were imaged and analyzed for PV, PNN, and PV+PNN counts in the superficial and deep regions of the prelimbic and infralimbic cortices. Averages counts within each group were taken and analyzed via 2-way ANOVAs for each brain region and dependent variable. RESULTS: DISC1-KO rats displayed the following trending changes: decreased PV cells in deep layers of infralimbic and decreased PNNs throughout the prelimbic cortex. MK-801 appears to increase the number of unsheathed PV cells in the superficial layers of prelimbic and infralimbic cortex. It decreased the number of PNNs in the prelimbic of wildtype animals but not in the DISC1-KO cohort. MK-801 moderately increased PV counts in DISC1-KO. CONCLUSIONS: This DISC1-KO model is a promising model of schizophrenia as we see the same directionality of decreases in PV and PNN as post mortem human studies. Furthermore, MK-801 is seen to have an increasing trend effect on PV cells, which should be considered when interpreting findings in future studies that look at these markers.

Four species of net-spinning caddisflies, Hydropsyche simulans Ross, Cheumatopsyche lasia Ross, Cheumatopsyche campyla Ross and Chimarra obscura (Walker) are common in the regulated portions of the Brazos River. Hydropsyche simulans spun capture nets with the largest meshdimensions; the two Cheumatopsyche species' nets had the next largest meshes, and Chimarra obscura spun nets with the smallest dimensions. Cheumatopsyche lasia and C. campyla constructed nets with similar sized meshes. The number of individuals m~2 and standing crop biomass were not significantly different among low, medium, and high velocities. Early hydropsychid instars fed on detritus while later instar H. simulans and C. campyla had larger proportions of animal material. Guts of later instar C. lasia individuals had a greater percentage of algae and diatoms.

Chondroitin sulfate proteoglycans (CSPGs) are found in specialized brain extracellular matrix structures termed perineuronal nets (PNNs). The chondroitin sulfate chains of these CSPGs are thought to have a strong effect on neuroplasticity, along with development, injury, and diseased states of the brain. Wisteria floribunda agglutinin (WFA) is a plant lectin used to identify PNN via staining; the pattern of this staining is changed upon schizophrenia. As such, one powerful method of probing the identity of the CS chains of PNNs and addressing what changes in CS identity occur during schizophrenia is to characterize the features of the CS which bind to the lectin. Methods for characterization of WFA-CS binding and their biological relevance were developed and evaluated. Commercially available CS was used to probe the binding affinity of the agglutinin to various regions of CS via hemagglutination inhibition assays and affinity gradient elution of CS bound to WFA. The size, sulfation extent, and fragment location in the CS chain from these eluates were determined using HILIC-LC-MS. As commercial sources can be used to elucidate the binding specificity of WFA, but not the actual relevant binding partner of WFA within the brain, PNN CS extractions were performed with a modified method aimed at reducing the timescale at which PNN CS can be obtained so as to allow similar experimentation on CS directly from PNN. The results pave the way for further determination of WFA-CS binding.

Finding integer solutions to linear equations has various real world applications. In the thesis, we investigate its application to the reachability analysis of Petri nets. Introduced by Petri in 1962, Petri net has been a powerful mathematical formalism for modeling, analyzing and designing discrete event systems. In the research community of Petri nets, finding a feasible path from the initial state to the target state in Petri net, known as reachability analysis, is probably one of the most important and challenging subjects. The reachability algebraic analysis is equivalent to finding the nonnegative integer solutions to a fundamental equation constructed from the Petri net. We apply our algorithm in this thesis to reachability analysis of Petri net by finding the nonnegative integer solutions to the fundamental equation. / Finding the optimal binary solution to a quadratic object function is known as the Binary Quadratic Programming problem (BQP), which has been studied extensively in the last three decades. In this thesis, by investigating geometric features of the ellipse contour of a concave quadratic function, we derive new upper and lower bounding methods for BQP. Integrating these new bounding schemes into a proposed solution algorithm of a branch-and-bound type, we propose an exact solution method in solving general BQP with promising preliminary computational results. Meanwhile, by investigating some special structures of the second order matrix and linear term in BQP, several polynomial time algorithms are discussed to solve some special cases of BQP. / In the realm of integer programming, finding integer solutions to linear equations is another important research direction. The problem is proved to be NP-Complete, and several algorithms have been proposed such as the algorithm based on linear Diophantine equations as well as the method based on Groebner bases. Unlike the traditional algorithms, the new efficient method we propose in this thesis is based on our results on zero duality gap and the cell enumeration of an arrangement of hyperplanes in discrete geometry. / Integer programming plays an important role in operations research and has a wide range of applications in various fields. There are a lot of research directions in the area of integer programming. In this thesis, two main topics will be investigated in details. One is to find the optimal binary solution to a quadratic object function, and the other is to find integer solutions to linear equations. / Gu, Shenshen. / Adviser: Wang Jun. / Source: Dissertation Abstracts International, Volume: 73-01, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2009. / Includes bibliographical references (leaves 98-103). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

A telepresença, como um refinamento da teleoperação, permite que o indivíduo controle não apenas a simulação mas a própria realidade. Uma vez que, esta proporciona a habilidade de manipular a realidade física remotamente em tempo real, através de sua representação virtual. Através da tecnologia de realidade virtual, pode-se criar uma grande diversidade de ambientes apropriados aos mais variados tipos de aplicações, possibilitando simulações de situações do mundo real em um ambiente ou mundo virtual. A aplicação de ambientes virtuais no processo de manufatura está relacionada tanto com a manutenção e treinamento, como também a criação e simulação de protótipos virtuais antes de sua utilização no chão-de-fábrica. O uso de redes de Petri para modelagem de ambientes virtuais, mostra-se como uma poderosa ferramenta gráfica/matemática que pode capturar naturalmente as principais características dos sistemas de realidade virtual, além de proporcionar resultados empíricos interessantes na verificação automática de concorrência e sistemas de tempo real. Por permitir modelar a computação não determinística e paralela, a modelagem de ambientes virtuais com redes de Petri é adequada não apenas para simulação, verificação e validação desses sistemas, mas para o próprio controle dos ambientes modelados. Ao associar os elementos de uma rede de Petri com os elementos do paradigma orientado à objetos de um conjunto de classes que constituem os objetos que irão compor os ambientes virtuais e os sistemas de telepresença, obtém-se uma valiosa ferramenta para o controle dos métodos dos objetos virtuais e reais a serem invocados. O objetivo deste trabalho é o desenvolvimento do modo de associação de redes de Petri com objetos virtuais e reais para controle de ambientes virtuais imersivos e telepresença, com base na descrição de um sistema de autoria de telepresença com controle em RP. Os resultados obtidos trarão avanços quanto ao desenvolvimento e implantação de aplicações de manufatura virtual em um ambiente de visualização 3D imersivo. / The telepresence, as a refinement of teleoperation, allows the individual not only to control the simulation but also the own reality. Since this provides the ability to manipulate the physical reality remotely in real time, through its virtual representation. Through the technology of virtual reality, one can create a wide variety of environments suitable for all kinds of applications, enabling simulations of the situations in a real world environment or virtual world. The application of virtual environments in the manufacturing process is related to both the maintenance and training, and also the creation and simulation of virtual prototypes before their use in the shop-floor. The use of Petri nets for modeling virtual environments, shows itself as a powerful graphics/mathematics tool that can capture the main features of virtual reality systems, as well as offering interesting empirical results in automatic verification of concurrence and real time systems. By allowing to model non-deterministic and parallel computation, modeling of virtual environments with Petri nets is appropriate not only for simulation, verification and validation of these systems, but also for controlling the environments modeled. By associating the elements of a Petri net with the elements of the object oriented paradigm of a set of classes that are the objects that will compose the virtual environments and telepresence systems, one gets a valuable tool for controlling of the methods of virtual and real objects to be invoked. The objective of this work is the development of the mode of association of Petri nets with virtual and real objects for controlling immersive virtual environments and telepresence, based on the description of a telepresence authoring system controlled by PN. The results will bring progress on the development and deployment of virtual manufacturing applications in an immersive 3D visualization environment.

A telepresença, como um refinamento da teleoperação, permite que o indivíduo controle não apenas a simulação mas a própria realidade. Uma vez que, esta proporciona a habilidade de manipular a realidade física remotamente em tempo real, através de sua representação virtual. Através da tecnologia de realidade virtual, pode-se criar uma grande diversidade de ambientes apropriados aos mais variados tipos de aplicações, possibilitando simulações de situações do mundo real em um ambiente ou mundo virtual. A aplicação de ambientes virtuais no processo de manufatura está relacionada tanto com a manutenção e treinamento, como também a criação e simulação de protótipos virtuais antes de sua utilização no chão-de-fábrica. O uso de redes de Petri para modelagem de ambientes virtuais, mostra-se como uma poderosa ferramenta gráfica/matemática que pode capturar naturalmente as principais características dos sistemas de realidade virtual, além de proporcionar resultados empíricos interessantes na verificação automática de concorrência e sistemas de tempo real. Por permitir modelar a computação não determinística e paralela, a modelagem de ambientes virtuais com redes de Petri é adequada não apenas para simulação, verificação e validação desses sistemas, mas para o próprio controle dos ambientes modelados. Ao associar os elementos de uma rede de Petri com os elementos do paradigma orientado à objetos de um conjunto de classes que constituem os objetos que irão compor os ambientes virtuais e os sistemas de telepresença, obtém-se uma valiosa ferramenta para o controle dos métodos dos objetos virtuais e reais a serem invocados. O objetivo deste trabalho é o desenvolvimento do modo de associação de redes de Petri com objetos virtuais e reais para controle de ambientes virtuais imersivos e telepresença, com base na descrição de um sistema de autoria de telepresença com controle em RP. Os resultados obtidos trarão avanços quanto ao desenvolvimento e implantação de aplicações de manufatura virtual em um ambiente de visualização 3D imersivo. / The telepresence, as a refinement of teleoperation, allows the individual not only to control the simulation but also the own reality. Since this provides the ability to manipulate the physical reality remotely in real time, through its virtual representation. Through the technology of virtual reality, one can create a wide variety of environments suitable for all kinds of applications, enabling simulations of the situations in a real world environment or virtual world. The application of virtual environments in the manufacturing process is related to both the maintenance and training, and also the creation and simulation of virtual prototypes before their use in the shop-floor. The use of Petri nets for modeling virtual environments, shows itself as a powerful graphics/mathematics tool that can capture the main features of virtual reality systems, as well as offering interesting empirical results in automatic verification of concurrence and real time systems. By allowing to model non-deterministic and parallel computation, modeling of virtual environments with Petri nets is appropriate not only for simulation, verification and validation of these systems, but also for controlling the environments modeled. By associating the elements of a Petri net with the elements of the object oriented paradigm of a set of classes that are the objects that will compose the virtual environments and telepresence systems, one gets a valuable tool for controlling of the methods of virtual and real objects to be invoked. The objective of this work is the development of the mode of association of Petri nets with virtual and real objects for controlling immersive virtual environments and telepresence, based on the description of a telepresence authoring system controlled by PN. The results will bring progress on the development and deployment of virtual manufacturing applications in an immersive 3D visualization environment.

Cette thèse s'intéresse à la vérification de systèmes automatisables par model-checking. La question sous-jacente autour de laquelle se construit la contribution est la recherche d'un compromis entre différents objectifs potentiellement contradictoires : la décidabilité des systèmes à vérifier, l'expressivité des formalismes de modélisation, l'efficacité de la vérification, et la certification des outils utilisés. Dans ce but, on choisit de baser la modélisation sur des réseaux de Petri annotés par des langages de programmation réels. Cela implique la semi-décidabilité de la plupart des questions puisque la responsabilité de la terminaison est remise entre les mains du modélisateur (tout comme la terminaison des programmes est de la responsabilité du programmeur). Afin d'exploiter efficacement ces annotations, on choisit ensuite une approche de compilation de modèle qui permet de générer des programmes efficaces dans le langage des annotations, qui sont alors exécutées de la manière la plus efficace. De plus, la compilation est optimisée en tirant partie des spécificités de chaque modèle et nous utilisons l'approche de model-checking explicite qui autorise cette richesse d'annotations tout en facilitant le diagnostique et en restant compatible avec la simulation (les modèles compilés peuvent servir à de la simulation efficace). Enfin, pour combattre l'explosion combinatoire, nous utilisons des techniques de réductions de symétries qui permettent de réduire les temps d'exploration et l'espace mémoire nécessaire. / This work focuses on verification of automated systems using model-checking techniques. We focus on a compromise between potentially contradictory goals: decidability of systems to be verified, expressivity of modeling formalisms, efficiency of verification, and certification of used tools. To do so, we use high level Petri nets annotated by real programming languages. This implies the semi-decidability of most of problems because termination is left to the modeler (like termination of programs is left to the programmer). To handle these models, we choose a compilation approach which produces programs in the model annotation language, this allows to execute them efficiently. Moreover, this compilation is optimizing using model peculiarities. However, this rich expressivity leads to the use of explicit model-checking which allows to have rich model annotations but also allows to easily recover errors from verification, and remains compatible with simulation (these compiled models can be used for efficient simulation). Finally, to tackle the state space explosion problem, we use reduction by symmetries techniques which allow to reduce exploration times and state spaces.

Thesis (M.S.)--University of Missouri--Rolla, 2007. / Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed November 30, 2007) Includes bibliographical references (p. 199-209).

<p>Routing techniques for plain ’flat’ microchips have been developed extensively and will soon reach its limitations. One natural step would be to develop chips which are manufactured in a more cubic type of volume, as oppose to the classical flat design. </p><p>This thesis proposes a method for routing two-point nets across a three- dimensional channel. The height required by this algorithm is of the order <i>O(n</i> ^(3/2)), where n is the number of terminals on a square top-layer with the side <i>2 (n</i>^(1/2)). </p><p>The algorithm proposed here is based on"On Routing Two-Point Nets Across a Channel", by Ron Y. Pinter [9], and the concepts from this paper are explainedin this thesis to familiarise the reader these. </p><p>It is also shown that the proposed algorithm is more effective in its volume than the two-dimensional counterpart. The algorithm here is of the order <i>O(n</i>^(3/2)) with the two-dimensional algorithm of the order <i>O</i>(<i>n</i>²).</p>