<p>Coronaviruses are the largest known RNA viruses and infect a wide range of hosts. Human coronaviruses traditionally have been known to be the cause of the common cold and have been vastly understudied due to low morbidity and mortality. The emergence of SARS-CoV and MERS-CoV has altered the landscape of coronavirus research and proven the deadly capabilities of human coronaviruses. With two recent zoonotic events, it is increasingly important to understand the molecular biology of human coronaviruses. The coronavirus nucleocapsid protein is an essential structural protein that complexes with the viral genome. Though nucleocapsid formation is the protein’s major role, it has also been found to have other functions and effects during infection. The following research aimed to examine how the human coronavirus nucleocapsid protein affects the innate immune response <em>in vitro</em>. Modulation of the type I interferon response by the nucleocapsid was first investigated and the nucleocapsids were shown to have the ability to block interferon signalling. Additionally, the nucleocapsid protein was found to cause a dysregulation of transcription factor NFKB1. We propose a novel mechanism of this NFKB1 negative regulation interference. Taken together, we have further characterized the significant role of the coronavirus nucleocapsid protein in innate immune evasion.</p> / Doctor of Philosophy (Medical Science)

Herpes simplex virus (HSV) infections are common in all human populations and for most people they represent relatively mild lifelong infections. To facilitate the persistent infection of hosts, HSV has evolved immune evasion strategies which suppress various aspects of the immune response including the actions of complement and antibodies. Previously in our laboratory, an HSV immediate early protein called ICP47 was shown to inhibit the MHC class I antigen presentation pathway and thereby block recognition of virus infected cells by CD8+ cytotoxic T lymphocytes (CTL). This thesis explores the potential cellular targets of ICP47. Using immunoprecipitation I found ICP47 associates with the transporter associated with antigen presentation (TAP). By blocking the transport of peptide antigens into the endoplasmic reticulum, MHC class I molecules become unstable and are subsequently degraded before displaying HSV antigens on the cell surface. Thus, CTL destruction of cells infected with HSV is blocked. In addition, an interaction between an ICP47 bacterial fusion protein, called GSTICP47-1 and a cellular protein, calcyclin, was examined. The functions of calcyclin are largely unknown. However, based on its association with ICP47, it was possible that calcyclin might play a role in the class I pathway -perhaps as the peptide shuttle. Nevertheless, the results of several experiments were consistent with the notion that calcyclin and ICP47 may not interact in vivo and that calcyclin may not play a role in the MHC class I antigen presentation pathway. / Thesis / Master of Science (MS)

In this dissertation we introduce a new class of pursuit-evasion games; the herding problem. Unlike regular pursuit evasion games where the pursuer aims to hunt the evader the objective of the pursuer in this game is to drive the evader to a certain location on the x-y grid. The dissertation deals with this problem using two different methodologies. In the first, the problem is introduced in the continuous-time, continuous-space domain. The continuous time model of the problem is proposed, analyzed and we came up with an optimal control law for the pursuer is obtained so that the evader is driven to the desired destination position in the x-y grid following the local shortest path in the Euler Lagrange sense. Then, a non-holonomic realization of the two agents is proposed. In this and we show that the optimal control policy is in the form of a feedback control law that enables the pursuer to achieve the same objective using the shortest path. The second methodology deals with the discrete model representation of the problem. In this formulation, the system is represented by a finite di-graph. In this di-graph, each state of the system is represented by a node in the graph. Applying dynamic programming technique and shortest path algorithms over the finite graph representing the system, we come up with the optimal control policy that the pursuer should follow to achieve the desired goal. To study the robustness, we formulate the problem in a stochastic setting also. We analyze the stochastic model and derive an optimal control law in this setting. Finally, the case with active evader is considered, the optimal control law for this case is obtained through the application of dynamic programming technique. / Ph. D.

Literature on tax evasion has generally ignored the effects of tax evasion by a monopolist in a regulatory environment. When the government is asymmetrically informed about the monopolist's demand and/or costs, however, the fIrm may have the opportunity to cheat on its regulatory constraint and tax payments. Adjustments in the regulatory constraint then will directly impact on the tax revenues of the government while alterations in tax policies may alter the effectiveness and efficiency results of a particular regulatory policy. To analyze these issues two forms of regulation, a price ceiling regulation and a fixed profit per unit regulation are considered in an environment where the government is incompletely informed about the monopolist's cost function. For the price ceiling regulation (Chapter 2) it is shown that tax evasion decisions are affected by variations in the ceiling in the sense that an increase in the effective price ceiling results in misreporting by a larger proportion. Tax evasion decisions however are found not to affect output decisions of the monopolist. Thus the optimal price ceiling under evasion is set at the same level as without tax evasion, i.e., at the point where price equals expected marginal cost. Optimality in this economy can be achieved in a number of ways. Full compliance is one way but optimality can also be achieved with tax evasion. When the form of regulation considered is a fixed profit-per-unit regulation (Chapter 3), the results are quite different from above. Because profits of the monopolist are not costlessly observable by the government, fIrms can cheat on the regulatory constraint itself. Thus output and tax evasion to affect the monopolist's output. Literature on tax evasion has often neglected the fact that income from different sources is taxed at different rates and provides different opportunities for misreporting. Once an individual obtains certain skills, his flexibility in switching jobs to evade taxes on his wage income becomes limited. Also the fact that a large part of the wage income in the U.S. is reported to the government by the employer and often withheld at the source, greatly limits the opportunity for evading wage taxes. However an individual faces many options when deciding on how to invest his savings and the income from at least some of these may not be subject to withholding and reporting. This fact suggests that the savings of an individual can be affected by tax evading opportunities. Chapter 4 examines this problem by considering a dynamic model of tax evasion. The results show that an increase in the penalty rate or audit probability leads to an increase in savings of the individual, given some assumptions on preferences. This fact implies that savings are reduced by the possibility of tax evasion. It also suggests that savings could be increased by stricter enforcement of tax laws. Because the model used in chapter 4 is fairly complicated, some of the comparative static results are found to be ambiguous under general conditions. It is also not clear from the theory what the optimal policy of the government would be. To address these issues in more details, chapter 5 considers some numerical exercises. A number of results emerge from these exercises. First, savings are found to increase with an increase in either the penalty rate or the audit rate, even when the restrictive assumptions on risk aversion do not hold and labor supply is variable. Second, full compliance seems to be the optimal policy of the government for the specification selected. These results seem to hold both for compensated and uncompensated taxes. / Ph. D.

Pursuit-evasion games are the subject of a variety of research initiatives seeking to provide some level of autonomy to mobile, robotic vehicles with on-board controllers. Applications of these controllers include defense topics such as unmanned aerial vehicle (UAV) and unmanned underwater vehicle (UUV) navigation for threat surveillance, assessment, or engagement. Controllers implementing pursuit-evasion algorithms are also used for improving everyday tasks such as driving in traffic when used for collision avoidance maneuvers. Currently, pursuit-evasion tactics are incorporated into the control by solving the Hamilton-Jacobi-Isaacs (HJI) equation explicitly, simplifying the solution using approximate dynamic programming, or using a purely finite-horizon approach. Unfortunately, these methods are either subject to difficulties of long computational times or having no guarantees of succeeding in the pursuit-evasion game. This leads to more difficulties of implementing these tactics on-line in a real robotic scenario where the opposing agent may not be known before the maneuver is required. This dissertation presents a novel method of solving the HJI equation by partitioning the state space into regions of local, finite horizon control laws. As a result, the HJI equation can be reduced to solving the Hamilton-Jacobi-Bellman equation recursively as information is received about an opposing agent. Adding complexity to the problem structure results in a decreased calculation time to allow pursuit-evasion tactics to be calculated on-board an agent during a scenario. The algorithms and implementation methods are given explicitly and illustrated with an example of two robotic vehicles in a collision avoidance maneuver. / Ph. D.

Recent studies have focused on dissolved organic matter (DOM) cycling throughout river corridors or in reservoirs, but few have explored DOM cycling in commonplace but understudied run-of-river (ROR) reservoir systems. Impoundments disrupt river flow patterns, as they increase hydraulic residence time and alter the flow of DOM downstream. During storms when the majority of DOM loading occurs, impoundments become less likely to hold DOM and will increase export of DOM downstream. In this study, we quantified DOM bioavailability and composition, carbon flux, and carbon dioxide (CO2) gas evasion in a ROR reservoir system at baseflow conditions and during a 1.5-year storm event. This study used a combination of high frequency spatial sensor data geotagged to GPS coordinates along the river to reservoir transition, and grab samples of surface water taken at two U.S. Geological Survey stream gauges and three additional sites. The landscape and shallow flow paths to ROR reservoir systems resulted in the export of both aromatic carbon and labile organic matter present within these waters, as water was mixed and exported downstream. Additionally, the reservoir was a net sink of DOC and BDOC flux, while also a source of DIC flux. Finally, CO2 evasion was magnified by high flow, with the reservoir changing from a sink to a source of CO2 to the atmosphere. ROR reservoirs may undergo "short-circuiting" during high flow, which alters DOM transformations and transport of carbon downstream. Our results provide critical insight on carbon dynamics in ROR reservoir systems and highlight the need to incorporate riverine DOM into carbon budgets, especially under variable flow conditions. / Master of Science / Recent studies have focused on dissolved organic matter (DOM) cycling through river corridors, as DOM provides energy to aquatic food webs and can be converted to carbon dioxide (CO₂) through microbial respiration. Few studies have explored DOM cycling in commonplace but understudied run-of-river (ROR) reservoir systems. ROR reservoirs are created by the implementation of a dam across a river channel and use the flow of the river to generate hydroelectric power. During storms, when the majority of DOM loading occurs, impoundments become less likely to hold DOM and will increase export of DOM downstream. In this study, we quantified DOM quality and composition, DOM transport, and carbon dioxide (CO₂) gas evasion in a ROR reservoir system at baseflow conditions and across a 1.5 year storm event. This study used a combination of high frequency spatial sensor data combined with GPS coordinates along the river to reservoir transition, and grab samples of surface water taken at two U.S. Geological Survey stream gauges and three additional sites. Results show that the landscape and shallow flow paths to ROR reservoir systems resulted in the export of both high and low quality carbon present within these waters, as water was mixed and exported downstream. Additionally, the reservoir was a net sink of DOM flux, retaining 40.7% of the total DOM loading for the storm event. Finally, CO₂ evasion was magnified by the storm event, with the reservoir changing from a sink to a source of CO₂ to the atmosphere. Our results provide critical insight on carbon dynamics in ROR reservoir systems and highlight the need to incorporate riverine DOM into carbon budgets, especially under variable flow conditions.

Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2018-01-25T14:05:31Z No. of bitstreams: 2 Dissertação - Thays Santos Souza - 2017.pdf: 4041758 bytes, checksum: 5c22d168b0e90bb2df12833c1eb4f1e2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-01-25T14:17:22Z (GMT) No. of bitstreams: 2 Dissertação - Thays Santos Souza - 2017.pdf: 4041758 bytes, checksum: 5c22d168b0e90bb2df12833c1eb4f1e2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-01-25T14:17:23Z (GMT). No. of bitstreams: 2 Dissertação - Thays Santos Souza - 2017.pdf: 4041758 bytes, checksum: 5c22d168b0e90bb2df12833c1eb4f1e2 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-12-18 / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / The survey was conducted under the optics of evasion by course, which considers evaded the student who abandons/desists from the course which they are enrolled before completing it. Among the factors contributing to a student to give up the course, which they are enrolled, are Academic-institutional factors; Socio-political-economic factors and Personal factors. In this context, the main objective of this study was to measure and understand the reality of evasion in the undergraduate courses at the Federal University of Goiás (UFG). For a greater range of the study, the evasion calculations were carried out in the period from 2014 to 2016, using mostly three formulas: the first formula was stipulated by the Special Committee on Evasion Studies, the second one was the formula used by the working group of the Forum for Pro-rectors of Planning and Management – FORPLAD and finally, the third formula was suggested by the College of Prorectors of graduation – COGRAD/ANDIFES. The courses with the highest average evasion rates found in the survey were: Social Sciences, Art Direction, Philosophy, Physics, Literature, Pedagogy and Chemistry. With the purpose of obtaining data, such as data collection instrument, 4 (four) questionnaires (validated research instruments) were applied, with objective and multiplechoice questions. The data obtained through the questionnaires were tabulated and exposed for comparison between the groups involved in the teaching-learning process. For qualitative analysis the software used was Webqda version 3.0. The main reasons that led students to evade the course were: the choice for another course, financial difficulty and difficulty transportation from UFG to home and vice versa. Socio-political-economic factors are the most cited as cause of evasion in the undergraduate courses at UFG. It is concluded that the academic trajectory is defined under a social standpoint, but it is influenced by the relationships defined in the academic area and groups in which the students are in. / A pesquisa foi realizada sob a óptica da evasão por curso, que considera evadido o estudante que abandona/desiste do curso o qual está matriculado antes de concluí-lo. Entre os fatores que contribuem para que um estudante desista do curso o qual está matriculado, estão: Fatores Acadêmico-Institucionais; Fatores Sócio-Político-Econômicos e Fatores de ordem pessoal. Diante deste contexto, o objetivo principal deste estudo foi mensurar e compreender a realidade da Evasão nos cursos de graduação presenciais na Universidade Federal de Goiás (UFG). Para maior alcance do objetivo do estudo os cálculos de evasão foram realizados no período de 2014 a 2016, a partir de três fórmulas: a fórmula estipulada pela Comissão Especial de Estudos sobre evasão, a segunda foi a fórmula utilizada pelo grupo de trabalho do Fórum de Pró-reitores de Planejamento e Administração – FORPLAD e por último, a terceira fórmula foi sugerida a do Colégio de Pró- reitores de Graduação – COGRAD/ANDIFES. Os cursos com as maiores taxas médias de evasão encontradas na pesquisa, foram: Ciências Sociais, Direção de Arte, Filosofia, Física, Letras, Pedagogia e Química. Com a finalidade de obtenção de dados, como instrumento de coleta de dados, foram aplicados 4 (quatro) questionários (instrumentos de pesquisas validados), com questões abertas e fechadas. Os dados obtidos através dos questionários foram tabulados e expostos com a finalidade de comparação entre os grupos envolvidos no processo de ensino-aprendizagem. Para análise qualitativa foi utilizado o software webqda versão 3.0. Os principais motivos que levaram os estudantes a abandonar o curso foram: escolha por outro curso, dificuldade financeira e dificuldade transporte UFG-CASA. Os fatores sócio-político-econômicos são os mais citados como causadores da evasão nos cursos de graduação presenciais na UFG. Conclui-se que a trajetória acadêmica é definida sob ponto de vista social, porém são influenciadas pelas relações definidas no meio acadêmico e espaços em que os estudantes estão inseridos.

The federal income tax system in the United States depends upon a high degree of voluntary compliance. The IRS estimates that the voluntary compliance level is declining and that this tax compliance gap cost the government an estimated $90.5 billion in 1981. Between 1979 and 1982, Congress made several changes in the tax laws designed to improve tax compliance. Extensive data was collected by the IRS for 1979 and 1982 through the random sample audits of approximately 50,000 taxpayers on the Taxpayer Compliance Measurement Program (TCMP), which is conducted every three years. During the period 1979 through 1982, Congress lowered the marginal tax rates, added some fairly severe penalties, for both taxpayers and paid return preparers, and increased information reporting requirements for certain types of income. In this research, it was hypothesized that voluntary compliance should increase in response to lower marginal rates, a higher risk of detection due to additional reporting requirements, and increased penalties. Multiple regression analysis was employed to test these hypotheses, using 1979 and 1982 TCMP data. Because of the requirements for taxpayer confidentiality, it was necessary for the IRS to run the data and provide the aggregate data results for the research. The results provided insight into the effectiveness of tax compliance legislation. While the overall voluntary compliance level (VCL) increased from 1979 to 1982 by 1.53 per cent, the VCL increase for taxpayers in high marginal rates was much smaller (.42 percent) than the overall increase. This is very inconsistent with the notion that high marginal rates are driving noncompliance, and suggests that marginal rates may not be strong determinants of compliance. Probably other factors, such as opportunity for evasion, may be more important. There was little change from 1979 to 1982 of the compliance of returns done by paid return preparers. Because of the timing of many TEFRA provisions (effective in 1983), further research for years after 1982 is needed.

Submitted by Filipe dos Santos (fsantos@pucsp.br) on 2017-07-18T12:03:26Z No. of bitstreams: 1 Rogério Albanez.pdf: 1157324 bytes, checksum: a56cb348235c64871966d4db55db48fc (MD5) / Made available in DSpace on 2017-07-18T12:03:27Z (GMT). No. of bitstreams: 1 Rogério Albanez.pdf: 1157324 bytes, checksum: a56cb348235c64871966d4db55db48fc (MD5) Previous issue date: 2017-06-22 / The school evasion factor, historically, occurs at all levels and types of education, causing social, economic, political, academic and financial damages to all those committed to education. The evasion phenomenon in universities has caused great disquiet in general. Failure to complete an undergraduate degree is detrimental to the student, the university and the community. This study examined both the profiles of the students that chose to take the Accounting Science degree at the Adventist University Center of São Paulo-UNASP, Campus São Paulo, and the reasons that led them to give up finishing their degree. The aim of this study was to call the university’s attention to the need to detect adjustments or changes necessary to better identify the factors that contribute to students' dissatisfaction related to the Accounting Sciences degree, establishing the reasons that led them to give up, such as their disinterest in the degree itself, and to demonstrate what the university is doing or could do, for example, to assign more qualified professors to teach the degree’s core courses, in order to avoid or reduce the occurrence of evasion. The research method used to obtain the necessary data was qualitative analysis, presenting references of other researches on the evasion factor in two perspectives: first, looking at the evasion phenomenon in several undergraduate courses at different universities in Brazil and second, looking at the event focusing exclusively on the Accounting Sciences degree at several universities scattered throughout the country. To complete the analysis, questionnaires were applied to the evaded students and to UNASP’s Accounting Sciences’ degree coordinator. The research showed that the major cause of evasion is the economic-financial factor. The lack of motivation and disillusionment with the degree was another very important factor, followed by other personal, institutional reasons and then others, such as health reasons / A evasão escolar, historicamente, ocorre em todos os graus e tipos de ensino. A evasão no ensino superior, diante do número de discentes que abandonam os cursos de graduação antes da sua conclusão, gera detrimento para o discente, para a instituição e para a comunidade. Este estudo examinou os perfis dos alunos que escolheram o curso de Ciências Contábeis no Centro Universitário Adventista de São Paulo, campus São Paulo, os motivos que os levaram a desistir e a compreensão do coordenador do curso sobre o assunto. Dado que o curso de Ciências Contábeis figura entre os quatro cursos em número de matrícula, de ingressantes e de evadidos, os objetivos deste trabalho foram obter dados para despertar à instituição a necessidade de detectar ajustes ou mudanças necessárias para amenizar os efeitos que contribuem com a evasão dos alunos do curso, especificando identificar seu perfil e os motivos da renúncia, o desinteresse pelo curso, demonstrar se a instituição possui política de contenção da evasão e demonstrar qual a situação atual, perante a formação acadêmica, dos alunos desistentes. Para isso, foi questionado quais as reais motivações que levaram o aluno a desistir do curso de Ciências Contábeis do Centro Universitário Adventista de São Paulo, campus São Paulo, e o que a instituição tem realizado para amenizar a evasão. Foi utilizado o método de pesquisa estudo de caso para a obtenção dos dados, empregando o método de análise qualitativa, apresentando referências de pesquisas sobre a evasão em duas perspectivas: abordando a evasão nos cursos de graduação em diferentes instituições de ensino e a outra, abordando o evento no curso de Ciências Contábeis, em várias instituições de curso superior e, completando a análise, foram aplicados questionários para os alunos evadidos e para o coordenador do curso. A pesquisa resultou que são várias as causas da fuga dos discentes do curso, como o fator econômico-financeiro, a falta de motivação e a desilusão com o curso seguido por motivos de ordem pessoal, institucional e até aqueles que ocorrem sem interferências do aluno

We study single-pursuer, line-of-sight Pursuit and Evasion games in polytopes in $\mathbb{R}^n$. We develop winning Pursuer strategies for simple classes of polytopes (monotone prisms) in Rn, using proven algorithms for polygons as inspiration and as subroutines. More generally, we show that any Pursuer-win polytope can be extended to a new Pursuer-win polytope in more dimensions. We also show that some more general classes of polytopes (monotone products) do not admit a deterministic winning Pursuer strategy. Though we provide bounds on which polytopes are Pursuer-win, these bounds are not tight. Closing the gap between those polytopes known to be Pursuer-win and those known not to be remains an problem for future researchers.