Since the first cases of HIV/AIDS disease were recognised in the early 1980s, a large number of mathematical models have been proposed. However, the mobility of people among regions, which has an obvious impact on the spread of the disease, has not been much considered in the modelling studies. One of the main reasons is that the models for the spread of the disease in multiple populations are very complex and, as a consequence, they can easily become intractable. In this thesis we provide various new results pertaining to the spread of the disease in mobile populations, including epidemic intervention in multiple populations. We first develop stochastic models for the spread of the disease in a single heterosexual population, considering both constant and varying population sizes. In particular, we consider a class of continuous-time Markov chains (CTMCs). We establish deterministic and Gaussian diffusion analogues of these stochastic processes by applying the theory of density dependent processes. A range of numerical experiments are provided to show how well the deterministic and Gaussian counterparts approximate the dynamic behaviour of the processes. We derive threshold parameters, known as basic reproduction numbers, for both cases above the threshold which the disease is uniformly persistent and below the threshold which disease-free equilibrium is locally attractive. We find that the threshold conditions for both constant and varying population sizes have the same form. In order to take into account the mobility of people among regions, we extend the stochastic models to multiple populations. Various stochastic models for multiple populations are formulated as CTMCs. The deterministic and Gaussian diffusion counterparts of the corresponding stochastic processes for the multiple populations are also established. Threshold parameters for the persistence of the disease in the multiple population models are derived by applying the concept of next generation matrices. The results of this study can serve as a basic framework how to formulate and analyse a more realistic stochastic model for the spread of HIV in mobile heterogeneous populations—classifying all individuals by age, risk, and level of infectivities, and at the same time considering different modes of the disease transmission. Assuming an accurate mathematical model for the spread of HIV/AIDS disease, another question that we address in this thesis is how to control the spread of the disease in a mobile population. Most previous studies for the spread of the disease focus on identifying the most significant parameters in a model. In contrast, we study these problems as optimal epidemic intervention problems. The study is mostly motivated by the fact that more and more local governments allocate budgets over a certain period of time to combat the disease in their areas. The question is how to allocate this limited budget to minimise the number of new HIV cases, say on a country level, over a finite time horizon as people move among regions. The mathematical models developed in the first part of this thesis are used as dynamic constraints of the optimal control problems. In this thesis, we also introduce a novel approach to solve quite general optimal control problems using the Cross-Entropy (CE) method. The effectiveness of the CE method is demonstrated through several illustrative examples in optimal control. The main application is the optimal epidemic intervention problems discussed above. These are highly non-linear and multidimensional problems. Many existing numerical techniques for solving such optimal control problems suffer from the curse of dimensionality. However, we find that the CE technique is very efficient in solving such problems. The numerical results of the optimal epidemic strategies obtained via the CE method suggest that the structure of the optimal trajectories are highly synchronised among patches but the trajectories do not depend much on the structure of the models. Instead, the parameters of the models (such as the time horizon, the amount of available budget, infection rates) much affect the form of the solution.

Since the first cases of HIV/AIDS disease were recognised in the early 1980s, a large number of mathematical models have been proposed. However, the mobility of people among regions, which has an obvious impact on the spread of the disease, has not been much considered in the modelling studies. One of the main reasons is that the models for the spread of the disease in multiple populations are very complex and, as a consequence, they can easily become intractable. In this thesis we provide various new results pertaining to the spread of the disease in mobile populations, including epidemic intervention in multiple populations. We first develop stochastic models for the spread of the disease in a single heterosexual population, considering both constant and varying population sizes. In particular, we consider a class of continuous-time Markov chains (CTMCs). We establish deterministic and Gaussian diffusion analogues of these stochastic processes by applying the theory of density dependent processes. A range of numerical experiments are provided to show how well the deterministic and Gaussian counterparts approximate the dynamic behaviour of the processes. We derive threshold parameters, known as basic reproduction numbers, for both cases above the threshold which the disease is uniformly persistent and below the threshold which disease-free equilibrium is locally attractive. We find that the threshold conditions for both constant and varying population sizes have the same form. In order to take into account the mobility of people among regions, we extend the stochastic models to multiple populations. Various stochastic models for multiple populations are formulated as CTMCs. The deterministic and Gaussian diffusion counterparts of the corresponding stochastic processes for the multiple populations are also established. Threshold parameters for the persistence of the disease in the multiple population models are derived by applying the concept of next generation matrices. The results of this study can serve as a basic framework how to formulate and analyse a more realistic stochastic model for the spread of HIV in mobile heterogeneous populations—classifying all individuals by age, risk, and level of infectivities, and at the same time considering different modes of the disease transmission. Assuming an accurate mathematical model for the spread of HIV/AIDS disease, another question that we address in this thesis is how to control the spread of the disease in a mobile population. Most previous studies for the spread of the disease focus on identifying the most significant parameters in a model. In contrast, we study these problems as optimal epidemic intervention problems. The study is mostly motivated by the fact that more and more local governments allocate budgets over a certain period of time to combat the disease in their areas. The question is how to allocate this limited budget to minimise the number of new HIV cases, say on a country level, over a finite time horizon as people move among regions. The mathematical models developed in the first part of this thesis are used as dynamic constraints of the optimal control problems. In this thesis, we also introduce a novel approach to solve quite general optimal control problems using the Cross-Entropy (CE) method. The effectiveness of the CE method is demonstrated through several illustrative examples in optimal control. The main application is the optimal epidemic intervention problems discussed above. These are highly non-linear and multidimensional problems. Many existing numerical techniques for solving such optimal control problems suffer from the curse of dimensionality. However, we find that the CE technique is very efficient in solving such problems. The numerical results of the optimal epidemic strategies obtained via the CE method suggest that the structure of the optimal trajectories are highly synchronised among patches but the trajectories do not depend much on the structure of the models. Instead, the parameters of the models (such as the time horizon, the amount of available budget, infection rates) much affect the form of the solution.

Diss. Linköping : Linköpings universitet, 2007.

Η συνηθέστερη εκδήλωση τις στεφανιαίας νόσου είναι η στηθάγχη, δηλαδή ο παροξυσμικός πόνος στο στήθος λόγω ανεπαρκούς αιμάτωσης και υποξίας. Από τις πιο σύγχρονες φαρμακευτικές αντιστηθαγχικές θεραπείες είναι η συστηματική διαδερμική χορήγηση νιτρογλυκερίνης μέσω εμπλάστρων ή αλλιώς patch. Στην ελληνική αγορά κυκλοφορούν ήδη 5 διαφορετικά τέτοια έμπλαστρα, απόδειξη ότι η φαρμακευτική αγορά είναι μια από τις πιο γρήγορα αναπτυσσόμενες και ταχύρρυθμα εξελίξιμες αγορές. Οι γιατροί οι οποίοι καλούνται να συνταγογραφήσουν καθένα από αυτά τα έμπλαστρα, έχουν κάνει την επιλογή τους με βάση κάποιους παράγοντες. Αυτή η εργασία μελετά ακριβώς αυτούς τους παράγοντες κατηγοριοποιώντας τους γιατρούς ανάλογα με την ηλικία τους, το φύλο τους και τον φορέα απασχόλησής τους. Συνοψίζοντας τα αποτελέσματα της εργασίας αυτής σε έναν συγκεντρωτικό πίνακα στο τέλος, καταλήγουμε στο ότι αν και υπάρχουν κάποιες διαφορές μεταξύ των απαντήσεων των ερωτηθέντων όσον αφορά το φύλο (οι γυναίκες λαμβάνουν πιο πολύ υπόψη τους την ποιότητα ζωή των ασθενών και την ευκολία χρήσης του σκευάσματος από τους άντρες), την ηλικία (οι νεαρότεροι γιατροί λαμβάνουν υπόψη τους περισσότερο την ποιότητα ζωής των ασθενών και την άποψη των συναδέλφων τους) και τον φορέα απασχόλησης (οι νοσοκομειακοί γιατροί λόγω του ότι περνάνε πολλές ώρες με συναδέλφους τους επηρεάζονται περισσότερο από την άποψή τους), αυτές δεν αντικατοπτρίζονται στην επιλογή συνταγογραφίας τους κάποιου συγκεκριμένου διαδερμικού χορήγησης νιτρογλυκερίνης. / The most usual symptomof the cardiovascular disease is angina pectoris, meaning a severe chest pain due to lack of perfusion and hypoxia. One of the most recent pharmaceutical antianginal treatments is the systematic transdermal patchnitroglycerin patch. Currently in the Greek market, there are 5 different patches, which show that this market is one of the most fast growing and evolutionary markets. The doctors who are called to prescribe these patches have made their choice based on some factors. This paper researches these factors by categorizing the doctors based on their sex, age and their workplace. While summarizing the results of this paper in a table, we conclude that while there are some differences between the answers concerning their sex (women take under consideration more seriously the quality of life of their patients and the easiness of use of the product), their age (younger doctors take more seriously the quality of life of their patients and the opinion of their colleagues) and their workplace (hospital doctor due to the fact that they spend more time with their colleagues, they are more influenced by their opinion) these differences are not been shown in their prescription habits of some specific nitroglycerin patch.

Nous avons mis en évidence la présence des phagocytes exprimant le lysozyme dans les Plaque de Peyer chez l’Homme et montré que, comme chez la souris, elles sont principalement localisées dans le SED et sont distinctes des cDC. Dans un deuxième temps, nous avons étudié dans les PP de souris la fonction des différentes populations de phagocytes nouvellement caractérisées. Nous avons en particulier étudié l’impact de la détection d’un acide nucléique d’origine virale par les phagocytes en utilisant un agoniste synthétique du TLR7 : le R848. Bien que TLR7 soit exprimé par les cellules dérivées de monocytes et les DC plasmacytoïdes mais pas par les cDC, nous avons mis en évidence un processus d’activation rapide des cDC impliquant le TNF. Celui-ci conduit à une migration des cDC depuis les villosités adjacentes au dôme vers les IFR et à une forte augmentation de l’expression du CMH-II, des molécules co-stimulatrices ainsi que des gènes dépendants de l’interféron. L’activation du TLR7 induit également une forte expression de la sous unité p40 de l’IL-12 par les LysoDC et certains macrophages. De manière intéressante, nous avons également observé une forte expression d’IL-12 p40 par les LysoDC et certains macrophages peu de temps après le sevrage. Cela nous a conduits à étudier le rôle de cette cytokine dans la mise en place de la réponse immunitaire mucosale. Notre étude a donc des répercussions sur la compréhension des mécanismes conduisant à la mise en place de la réponse immunitaire mucosale en réponse à l’implantation du microbiote intestinal peu de temps après la naissance. / In this study, we first showed that lysozyme expressing cells are found in human PP and share features with their mouse counterpart, such as location and origin. Then, we investigated the behaviour of mouse PP phagocytes upon TLR7 stimulation, using the small synthetic agonist, R848. In PP TLR7 is expressed by monocyte derived cells and plasmacytoid DC, but not by cDC. Nevertheless, TLR7 stimulation triggers a quick activation of cDC. This activation relies on TNF secretion and leads to a massive migration of cDC from the dome associated villi to the IFR and to an increase of MHCII, co-stimulatory molecules and interferon-stimulated gene expression. Stimulation by TLR7 also induces a massive production of IL12p40 by LysoDC and some macrophages. Interestingly, we observed a similar increase of IL-12 p40 production by LysoDC and macrophages shortly after weaning. We thus investigated the impact of Il-12 p40 secretion on the development of the mucosal immune response. Therefore, our study provides clues on the mechanisms involved in the establishment of the mucosal immune response following microbiota colonization.

No description available.

The use of piezoelectric materials for actuation, and vibration suppression of thin beams, is the subject of study in this doctoral thesis. The initial focus is set on reducing beam vibrations with resistively shunted piezoelectric patches, where the converted electrical energy is dissipated by the resistor to give an additional damping. The amount of additional damping achieved depends on the value of shunted resistor, the dimensions of the piezoelectric, and its location on the substructure. Hence, the resistively shunted piezoelectric-beam was modelled to determine the optimal values, and to examine its dynamics. A multi-modal model was derived based on the Euler-Bernoulli beam theory, and a reduced non-dimensionalized transfer function was obtained from the multi-modal model. The presented model was derived from assumptions which aptly describe the dynamics of the resistively shunted piezoelectric-beam. The aptness of the presented model in representing the system, over the existing models, was evident from the comparison of the analytical predictions with the existing experimental data. With the model derived, the second part of the work deals with determining the value of resistance which would yield maximum amplitude attenuation (referred as the optimal resistance value). A method for obtaining the optimal resistance value from the analytical model, based on the presence of a fixed-point in the amplitude response, exists in the literature. But, this method cannot be used on the presented analytical model, as it includes the base-damping of the structure. Hence, a different approach was adopted to determine the optimal resistance from the analytical model. Analytical results were also validated with experimental results from a cantilever piezoelectric-beam. The amplitude plots of the first, second, and third modes of the piezoelectric-beam exhibited a softening e ect, indicating a non-linear behaviour of the piezoelectric patches. Hence, a non-linear constitutive equation was required to describe the behaviour of the piezoelectric patches. In the third part of the work, a two-step experimental procedure was devised to construct the non-linear constitutive equation of the piezoelectric actuators. In the first step, the piezoelectric patches were short circuited and a family of displacement curves were obtained for the first, second and third modes of the piezoelectric-beam by base excitation. The pro le of backbone curves from these plots were used to identify the type of non-linear terms required to describe the mechanical domain. In the second step, voltage excitation was used to obtain a similar set of displacement curves. A comparison of the profile of the backbone curves, of the displacement frequency response plot, from the voltage excited data with those from the base excited data, lead to the identification of the non-linear electromechanical coupling term. The constitutive equation, which accounts for the non-linear nature, of the piezoelectric actuator contains (apart from the linear terms) a quadratic strain term, a cubic strain term, and a term with the product of cubic strain and electric field.

Master of Science / Department of Civil Engineering / Mustaque A. Hossain / Based on a 2017 report on infrastructure by the American Society of Civil Engineers, 13% of Kansas public roads are in poor condition. Furthermore, reconstruction of a two-lane concrete pavement costs between $0.8 and $1.15 million dollars per lane mile. High early strength Portland cement concrete pavement (PCCP) patches are widely used in pavement preservation in Kansas due to the ability to open to traffic early. However, these repairs done by the Kansas Department of Transportation (KDOT) deteriorate faster than expected, though, prompting a need for inexpensive, durable high early strength concrete repair mixtures that meet KDOT standards (i.e., a 20-year service life). This study developed an experimental matrix consisting of six PCCP patching mixture designs with varying cement content and calcium chloride dosage. The mixtures were subjected to isothermal calorimetry, strength testing, drying shrinkage, and various durability tests. The effects of cement content and calcium chloride dosage on concrete strength and durability were then investigated. In addition, the compressive strength development with time, the split tensile versus compressive strength relationship, and the shrinkage strain of the PCCP patching mixtures were compared to established relationships provided by the American Concrete Institute (ACI). Results showed a maximum 3% increase in total heat generated by various concrete paste samples in isothermal calorimetry testing. The minimum compressive strength of 1,800 psi required by KDOT could likely be obtained using any of the PCCP mixtures, regardless of the cement content or calcium chloride dosage used in the study. Furthermore, surface resistivity tests for mixtures containing calcium chloride could result in erroneous measurements. Only one mixture satisfied the maximum expansion and minimum relative dynamic modulus of elasticity required by KDOT. Some ACI relationships for shrinkage and strength development do not appear to be valid for high early strength PCCP patching mixtures.

Submitted by Cláudia Bueno (claudiamoura18@gmail.com) on 2016-06-08T18:27:22Z No. of bitstreams: 2 Tese - Poliana Mendes - 2015.pdf: 2524794 bytes, checksum: eb8b9fab8d3f5746e746f1dbc2f546ab (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-06-09T11:32:11Z (GMT) No. of bitstreams: 2 Tese - Poliana Mendes - 2015.pdf: 2524794 bytes, checksum: eb8b9fab8d3f5746e746f1dbc2f546ab (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-06-09T11:32:11Z (GMT). No. of bitstreams: 2 Tese - Poliana Mendes - 2015.pdf: 2524794 bytes, checksum: eb8b9fab8d3f5746e746f1dbc2f546ab (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-06-08 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Our aim was to explore some components of bat responses to land-use changes. Bats were sampled in 18 forest patches during four nights. Landscapes were delimited with 500 meter to 10km radius from sample site. We took metrics of two different landscape components: natural vegetation amount and fragmentation (measured as number of patches). In the first chapter we tested the effect of such components in total abundance, species richness and variance in biological traits of bats. In the second chapter we verified if those variables were more important than local ones to determine occupancy probability of eight bat species. Local variables were tree density, understory height, liana quantity, and canopy cover. In the third chapter we counterposed species climatic suitable areas with spatial data about habitat loss and fragmentation in Cerrado. We predicted species vulnerability creating scenarios in which they were sensitive to habitat loss and/or fragmentation, furthermore we showed an overview of species suitable areas exposure to land-use changes to eight bat species. We observed idiosyncratic patterns of responses to habitat loss and fragmentation in bats. Abundance is positively related to habitat amount, whereas species richness, variance in body mass and number of guilds is negatively related to fragmentation. Occupancy probability of Sturnira lilium is positively related to habitat amount, whereas occupancy probability of Myotis nigricans is negatively related to fragmentation. Six other species did not show any clear relationship between occupancy and landscape structure. South areas of Cerrado are locales with higher climatic suitability, while still having higher exposure level to land-use changes. Our results strengthen the view that species response patterns to habitat loss and fragmentation are species-specific and also diversity metric specific. Such assertion reinforces that it is necessary an improvement in knowledge about factors that determine those responses, however it does not mean that the development of regional conservation strategies is unfeasible when using the current available knowledge in literature. / Esse trabalho teve como objetivo explorar alguns componentes das respostas dos morcegos a mudanças na estrutura da paisagem. Morcegos foram amostrados em 18 fragmentos florestais durante quatro noites. Foram delimitadas paisagens com entre 500 metros e 10 km de raio a partir do local de amostragem. Métricas de dois componentes da paisagem foram medidas nestas paisagens: a quantidade de vegetação natural e a fragmentação dessa vegetação (medido como o número de manchas). No primeiro capítulo testamos o efeito desses dois componentes na abundância total, riqueza de espécies e variância em traços biológicos de morcegos. No segundo capítulo verificamos se essas variáveis eram mais importantes do que variáveis locais para determinar a probabilidade de ocupação de oito espécies de morcegos. As variáveis locais foram obtidas em três quadrantes no local de amostragem de morcegos, onde se obteve a densidade de árvores, altura do sub-bosque, quantidade de lianas e, cobertura do dossel. No terceiro capítulo, a adequabilidade climática das espécies no Cerrado foi contraposta com dados espacializados da quantidade de vegetação natural e fragmentação. Essa contraposição teve como o objetivo predizer a vulnerabilidade de espécies se elas fossem sensíveis a um limiar de perda de habitat ou fragmentação na paisagem, além de mostrar de forma geral a exposição às mudanças na paisagem das áreas climaticamente adequadas para oito espécies de morcegos. Observa-se, de uma forma geral, padrões idiossincráticos de respostas a perda de habitat e fragmentação em morcegos. A abundância total é positivamente relacionada com a quantidade de habitat, enquanto que a riqueza de espécies, a variância na massa corporal e o número de guildas são negativamente relacionados com a fragmentação. A probabilidade de ocupação de Sturnira lilium é positivamente relacionada com a quantidade de habitat, enquanto que a probabilidade de ocupação de Myotis nigricans é negativamente relacionada com a fragmentação. Outras seis espécies não mostraram uma clara relação da probabilidade de ocupação com a estrutura da paisagem. Áreas do sul do Cerrado são locais com maiores valores de adequabilidade e, ao mesmo tempo, maiores exposições às mudanças na paisagem. Os resultados dos três capítulos fortalecem uma visão na literatura de que o padrão de respostas das espécies de morcegos à perda de habitat e fragmentação é específico para a espécie e para o componente de diversidade medido. Esta afirmação reforça o argumento de que um maior conhecimento sobre os fatores que determinam essas respostas é necessário, porém não inviabiliza o desenvolvimento de estratégias regionais de conservação utilizando o conhecimento já disponível na literatura.

This report covers the development of the web application Festing and the results and experiences which have been reached and learned during the process. The purpose of the study was to examine how the selling of patches could be both simplified and improved by using an advanced web application designed with focus on usability. Currently the patches are sold in a large but geographically and temporally limited market at Linköping University. The project was comprised of a case study and development of an application following the agile project framework Scrum. According to this the projects has been split up into four sprints after each of which a working product was delivered. This resulted in a usable web application with an intuitive design and multiple functions linked to the selling and buying of patches. Based on interviews, surveys and usability tests this web application is considered to have the long-term potential to take over the current physical market of textile patches. / Rapporten omfattar beskrivningen av utvecklingsprocessen för webbapplikationen Festing samt resultat och erfarenheter som uppnåtts och anskaffats under processens gång. Syftet med studien var att utveckla en avancerad webbapplikation av typ e-butik för att undersöka hur försäljningen av tygmärken kan förenklas och förbättras av en webbapplikation med fokus på användbarhet. Detta då försäljningen i dagsläget består av en stor men fysiskt och geografiskt begränsad marknad vid Linköpings universitet. Projektet har utformats som en fallstudie och utveckling av en webbapplikation enligt det agila arbetssättet Scrum. Arbetet har delats upp i fyra stycken olika sprintar där det i slutet av varje sprint ska ha levererats en fungerande delprodukt. Detta resulterade i en användbar webbapplikation med intuitiv design och flertalet funktioner kopplade till försäljning och köp av tygmärken. Utifrån intervjuer, enkätundersökningar och användbarhetstester anses denna webbapplikation ha potential till att på lång sikt kunna ta över den nuvarande fysiska försäljningen av tygmärken.