Dissertations / Theses on the topic 'Evasion'
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1
Pasolini-Fédida, Cathy. "Evasion fiscale internationale." Nice, 2000. http://www.theses.fr/2000NICE0006.
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L'évasion fiscale internationale consiste pour le contribuable à utiliser les failles des systèmes juridiques et non d'en violer les règles. Cette pratique n'est possible que grâce à l'existence des paradis fiscaux. En cernant les caracteristiques de ces pays à régimes fiscal privilégié, nous constatons que certains présentent des avantages pour les personnes physiques, tels que Monaco ou Andorre, et d'autres pour les personnes morales, tels que Jersey ou les Bahamas. Chaque paradis fiscal a sa spécificité et leur utilisation est savamment maniée par les contribuables qui en sont clients. Ainsi, deux méthodes essentielles permettent l'évasion fiscale : il s'agit tout d'abord d'une stratégie fiscale mise en place au sein d'un groupe de sociétés entrainant la manipulation des prix de transfert. La seconde méthode consiste en la création d'une société intermédiaire, dont le type le plus repandu est la société holding. Bien entendu, la répression des abus est nécessaire. Elle se situe au niveau législatif, avec notamment la maitrise des transferts de bénéfices à l'etranger. Mais cette lutte est également présente au niveau international, grâce à la création de nombreuses conventions fiscales bilatérales et multilatérales, ayant pour modèle la convention de l'organisation pour la coopération et le développement en Europe.
2
Sennoga, Edward Batte. "Essays on Tax Evasion." Digital Archive @ GSU, 2007. http://digitalarchive.gsu.edu/econ_diss/18.
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Essay one develops and tests a revenue-maximizing tax structure model. This model represents one of the first attempts to evaluate and compare the responsiveness of various tax instruments to tax evasion within a tax revenue maximization framework. We use data from both the OECD and East African countries and estimation is via a seemingly unrelated regression model. The GDP share of agricultural income is used as an instrument to correct for the simultaneity between tax revenue shares and tax evasion. Our findings indicate that tax evasion increases the tax authority’s reliance on consumption taxes vis-à-vis taxes on income, suggesting that diverse tax instruments respond differently to tax evasion, and as such the choice of a revenue-maximizing tax structure is influenced by the amount of revenue lost through tax evasion. Essay two analyzes the incidence of tax evasion in both the formal and informal sectors of the economy using a computable general equilibrium model. This essay incorporates the element of uncertainty in an individual’s decision to evade so as to account for the uncertainty of returns to the tax evader. We also allow for varying degrees of competi¬tion or entry across sectors in the economy to examine how much of the tax advantage is retained by the initial evaders and how much is shifted via factor and commodity price changes. Our simulation results show that the evading households’ post-evasion welfare is only 0.68-3.40 percent higher than the post-tax welfare if it had fully complied with taxes. The simulation results further reveal that the evading household keeps 77.1-83.2 percent of this initial increase in welfare, while 16.8-22.9 percent of this initial gain is competed away as a result of increased competition and entry into the informal sector. The compliant households’ welfare increases by 58.8-101.7 percent with increased competition in the informal sector. Therefore, if we construe the changes in consumer welfare as an overall indicator of the gains and/or losses from tax evasion, then the evading household only benefits marginally and this advantage diminishes with increased entry or competition in the informal sector.
3
Close, Helen Judith. "Immune evasion in glioma." Thesis, University of Leeds, 2016. http://etheses.whiterose.ac.uk/16103/.
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Glioblastoma multiforme (GBM) is the most common form of primary brain cancer and the current prognosis for patients is poor. New therapies are required that target the invasive cells that are characteristic of GBM. GBM is infiltrated by immune cells but, as with other cancers, immune evasion pathways minimise productive anti-tumour immunity. Natural killer (NK) cells are able to recognise and kill tumour cells and are being developed for the immunotherapy of other cancers. The aim of this work was to analyse the interaction between human NK cells and GBM cells in vivo and in vitro, as a prerequisite to future NK cell based immunotherapy of GBM. Analysis of the cell surface phenotype for GBM infiltrating NK and T cells revealed that the tumour microenvironment exerts localised immune evasion mechanisms which downregulate activation receptors and upregulate inhibitory receptors. The interaction of NK cells with patient-derived GBM stem cells, which are thought to be responsible for recurrent disease, was investigated in vitro. A high-throughput, multiplex flow cytometry-based screen of tumour cells revealed the expression of a number of cell surface molecules that regulate NK cell activation. Furthermore, GBM cells were more susceptible to NK cell lysis in vitro compared to a non-cancerous neural progenitor cell line, revealing specificity in the NK cell response. Furthermore, this screen identified potential mechanisms by which GBM might evade immune surveillance in vivo. Targeting these pathways and restoring functional immune surveillance provides a potential route for future immunotherapy of this disease. However, GBM patients often experience cerebral oedema and are treated with immunosuppressive corticosteroids, such as dexamethasone; this induces a similar immunosuppressed phenotype to that observed with the GBM infiltrating NK cells, and inhibits their lytic function. Gene expression profiling identified the transcription factor c-Myc as a key regulator of NK cell activation and as a hub for the immunosuppressive action of steroids and the immunosuppressive cytokine TGF-β. The demonstration that therapeutic steroids target the same pathway as TGF-β and induce immunosuppression has important implications for the use of steroids in patients undergoing immunotherapy.
4
Rossi, Antonio <1996>. "The Evasion of Emotions." Master's Degree Thesis, Università Ca' Foscari Venezia, 2020. http://hdl.handle.net/10579/18402.
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Since 1950s, starting with Schmölders’ publication, it has been ascertained that behavioural
aspects have consequences on tax evasion, tax compliance and tax morale.
Most of the researches in this field have focused on two aspects: explaining how tax
behaviours are affected by individuals’ situation and by their social contest, and
creating the microstructured datatsets required for such analysis. Following the tradition,
this thesis will firstly presents an analysis on the psychological framework
used to explain tax related behaviours, in particular with respect to tax evasion
reporting by fellow citizen. In this study, citizens’ sentiment towards the local and
national level administration is proxied through sentiment indexes based on geolocated
twitter data. Secondly, it uses a dataset from the website evasori.info: who
gathers anonymous reports from people which record illegal fiscal events as, for example,
not emitted fiscal documents. It also records tax evaded amounts, economic
sector, geolocalization of the event and even if the report ended with a signalling
to the Italian tax police called Guardia di Finanza. The aim of the thesis is to investigate
if there exists dependencies between spatial, social, demographic variables
and the probability to report the aforementioned facts given that the illicit has actually
happened and the reporter knew the existence of the website. This study will
highlight the active role played by citizens tax behaviour and explain which factors
affect their choice of signalling the event to the tax police. In addition, this study
will explore changes in the reported tax evasion events, and their amounts, through
time and space. To catch the essence of cultural and economic differences among
different areas of Italy, three italian provinces will be analysed: Rome, Milan and
Naples. The timespan taken in consideration brings together three governments:
Monti’s, Renzi’s and Conte I’s ones. The empirical model will consist of a logit
regression, in order to obtain indicators of how much individuals of different areas
have different propensions to report illegal tax evasion behaviours to the tax police.
5
Althorpe, Nicola Jayne. "Plasmid-mediated restriction evasion mechanisms." Thesis, University of Leicester, 1999. http://hdl.handle.net/2381/30313.
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Plasmid ColIb-P9 (Incll) encodes mechanisms which allow it to avoid destruction by type I and type II restriction enzymes during transfer by conjugation between strains of Escherichia coli. A genetic system was developed to analyse these mechanisms. The system relied on measuring Collb-mediated rescue of the restriction-sensitive plasmid R751 (IncPp) from destruction by EcoKI (type I) and EcoRI (type II). One Collb mechanism was known to involve a plasmid-encoded antirestriction gene known as ardA, the product of which is active against type I enzymes. Tests for alleviation of EcoKI restriction of R751, showed strong protection by a co-transferring Collb (Ard+) plasmid, slight protection when Collb was resident in the recipient and no effect when Collb was immobilised in the donor by removal of its nic site. Hence, expression of ardA is activated in the recipient cell following transfer no detectable transfer of the ArdA protein occurs from the donor to the recipient. The ardA gene is found in the leading region of Collb, which is defined as the first segment of the plasmid to enter the recipient cell during conjugation. Nucleotide sequencing of 11.7 kb of this region identified ten open reading frames. Furthermore, the region also contains three dispersed repeat sequences homologous to a novel single-stranded DNA promoter described by Masai and Arai (1997, Cell 89, 897-907). It is proposed that these secondary structures form in the transferring T-strand of Collb and function as promoters for transcription of genes encoded on the unique plasmid strand transferred during conjugation. Another mechanism, which acts independently of ardA, alleviates restriction of both type I and type II enzymes in the recipient in second or subsequent rounds of transfer. Two separate mechanisms appear to be operating since alleviation of type I restriction occurs in trans and is constitutive. In contrast, alleviation of type II restriction is by a czs-acting mechanism. The 'substrate saturation' hypothesis, whereby increasing amounts of transferred DNA saturates the restriction system (Read et al. 1992, Mol Microbiol 6, 1933-1941) is ruled out by data presented.
6
Odeberg, Jenny. "Human cytomegalovirus immune evasion strategies /." Stockholm, 2002. http://diss.kib.ki.se/2002/91-7349-126-8.
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Gmyrin, A. A. "Criminological characteristics of tax evasion." Thesis, Національний авіаційний університет, 2020. http://er.nau.edu.ua/handle/NAU/41673.
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In scientific research and practice, various instruments are used for the disclosure of the content of the crime, which include, for example, criminal law,forensic and criminological characteristics, each of which reveals the content of the subject matter of the study (crime, criminal activity) from its own special point of view. With regard to the criminal legal characteristic, it is of great importance for a complete and objective assessment of the act committed, as well as for determining the boundaries and scope of application of the criminal
law.In scientific research and practice, various instruments are used for the disclosure of the content of the crime, which include, for example, criminal law,forensic and criminological characteristics, each of which reveals the content of the subject matter of the study (crime, criminal activity) from its own special point of view. With regard to the criminal legal characteristic, it is of great importance for a complete and objective assessment of the act committed, as well as for determining the boundaries and scope of application of the criminal law.
8
Li, Dongxu. "Multi-player pursuit-evasion differential games." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1164738831.
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Turner, Sean C. "Essays on Crime and Tax Evasion." Digital Archive @ GSU, 2010. http://digitalarchive.gsu.edu/econ_diss/64.
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This dissertation consists of three essays addressing two issues related to crime and tax evasion. The first essay investigates the relationship between property and violent crime with law enforcement expenditures. The second essay examines the market structure in transition economies and the effects on firm-level tax evasion. The third essay investigates the incidence of tax evasion in a general equilibrium framework. The topics in all three essays are linked by their focus on criminal or illegal behavior. The essays also answer questions related to developing sound governmental policy and decision-making.
Chapter one attempts to identify the impact on crime of increasing law enforcement expenditures. We examine the specific channels the public has to influence crime (e.g., the level of expenditures, the number of police officers), to determine what role, if any, they may play in influencing crime rates for property crime and for violent crime. Conclusions in previous research are equivocal, and often do not adequately address the obvious simultaneity of crime and enforcement efforts. We use the Arellano-Bond system GMM estimation method to control for this simultaneity. Results from our preferred GMM estimation method show clearly that increases in law enforcement expenditures help reduce crime rates; other methodologies typically give results that are not robust.
The second chapter extends previous empirical work evaluating the determinants of tax evasion by firms in which tax evasion may be similar to a tax advantage under the law. This chapter contributes to the tax evasion literature by identifying market structures in which it may be easier to evade or where high levels of evasion take place. Results indicate that fighting corruption is still an important factor in determining the level of evasion. However, the data also suggests a long run situation in which the tax advantage of evasion has been replicated and competed away; more competitive markets have lower levels of evasion whereas monopolistic markets have higher levels of evasion. Further, tax evasion will occur in more service oriented industries.
Chapter three develops and calibrates a general equilibrium model to investigate how tax evasion affects the incidence of taxes. Previous tax incidence work has considered tax evasion; however little has been done considering the distributional impact of tax evasion. There may be cases in which individuals, other than evaders, indirectly benefit or lose from tax evasion. This work contributes to the literature by clearly linking the individual or firm decision to evade to a general equilibrium analysis of tax evasion using microeconomic foundations. Including evasion decisions in tax incidence analysis has implications for both tax policy and enforcement agency decision making, and is an important step toward understanding how evasion affects the whole economy.
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Solis, Mayra. "Immune evasion mechanisms by HIV-1." Thesis, McGill University, 2011. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=103531.
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Induction of the innate immune response by viral pathogens is characterized by a rapid production of Type I interferons (IFNβ/α). Recognition of viral components by Toll-like receptors (TLRs) or RIG-I-like receptors (RLRs), initiates multiple intracellular signalling cascades that culminate in the activation of the transcription factor NF-B and the interferon regulatory factors-3 and 7 (IRF-3 and IRF-7). As a consequence, these events lead to the production of immunoregulatory molecules, including Type I IFNs, pro-inflammatory cytokines and IFN-stimulated genes (ISGs), resulting in the inhibition of virus replication. Throughout evolution, viruses have developed strategies to subvert the innate immune response for their own benefit. Human immunodeficiency virus type-1 (HIV-1), the etiological agent of the acquired immunodeficiency syndrome (AIDS), has been shown to evade the innate immune response, resulting in disease progression. Thus, understanding the distinct mechanisms by which HIV-1 modulates TLRs and RLRs signaling pathways will ultimately lead to the development of novel strategies to inhibit HIV-1 replication and propagation. Studies have indicated that TLRs that signal via NF-B enhance HIV-1 replication. However, TLR4 stimulation triggers both NF-B and the IFN pathway and thus may have inhibitory effects on HIV-1 replication. Our first study was aimed at better understanding the role of TLR4 in HIV-1 replication. Therefore, we first characterized IRF-3 and IRF-7 activation following TLR4 stimulation. Our results demonstrate that the non-canonical TBK1 and IKKε are activated with distinct kinetics resulting in the activation of IRF-3 and subsequent induction of Type I IFNs. Thus, activation of the IFN pathway via TLR4 stimulation can provide a novel strategy to inhibit HIV-1 replication. Our second study sought to further delineate the different signaling pathways activated by HIV-1. Accordingly, transcriptional changes induced by distinct HIV-1 subtypes in immature dendritic cells were examined by microarray analysis. Our findings demonstrate that during the late phase of HIV-1 infection, a subset of genes is differentially regulated by the subtypes. In addition, this study highlights the important role of immature dendritic cells in HIV-1 replication and dissemination. Finally, given the importance of RLRs in the recognition of RNA viruses, the objective of the final study was aimed at investigating the evasion mechanisms employed by HIV-1 to counteract the initial antiviral response. Our results reveal that HIV-1 RNA is detected by the cytosolic receptor RIG-I. However, the HIV-1 viral protease sequesters RIG-I to the lysosomes and thus inhibits RIG-I-mediated antiviral response. Overall, the research presented in this thesis provides new avenues for developing novel therapeutic and preventive strategies to combat HIV-1/AIDS.L'induction de la réponse immunitaire innée par des pathogènes viraux est caractérisée par une production rapide des interférons de Type I (IFNβ/α). Les Toll-like (TLR) ou RIG-like (RLR) récepteurs détectent divers composants viraux induisant multiples voies de signalisation intracellulaire impliquées dans l'activation du factor de transcription-NF-B- ainsi que des facteurs de régulation de l'interféron-3 et -7 (IRF-3 et IRF-7). Ces évènements mènent à la synthèse de molécules immunorégulatrices, tel que les interférons (IFN) de Type I, les cytokines pro-inflammatoires et les gènes stimulés par l'IFN (ISG), qui jouent un rôle important dans l'inhibition de la réplication virale. Au cours de l'évolution, les virus ont développé des stratégies pour contrer la réponse immunitaire innée afin de se répliquer. Le virus de l'immunodéficience humaine de type 1(VIH-1), l'agent infectieux du syndrome de l'immunodéficience acquise (SIDA), échappe à la réponse immunitaire innée, ce qui favorise la progression de la maladie. Par conséquent, une meilleure compréhension des mécanismes par lesquels le VIH-1 module les voies de signalisation des TLR et des RLR pourrait mener au développement de nouvelles stratégies thérapeutiques pour empêcher la réplication et donc la propagation du VIH-1. Des études ont démontré que les TLR qui signalent par l'intermédiaire de NF-B augmentent la réplication du VIH-1. Cependant, la stimulation du TLR4 déclenche à la fois la voie de signalisation de NF-B et celle des IFN, pouvant avoir ainsi des effets inhibiteurs sur la réplication du VIH-1. L'objectif de notre première étude était de comprendre le rôle du TLR4 dans la réplication du VIH-1. Par conséquent, nous avons caractérisé la voie d'activation des IRF-3 et IRF-7 suite à la stimulation du TLR4. Nos résultats démontrent que les kinases non-canoniques TBK1et IKKε sont activées avec une cinétique distincte ayant pour conséquence l'activation de l'IRF-3 et l'induction subséquente des IFN de type I. Par conséquent, l'activation de la voie de signalisation des IFN par la stimulation du TLR4 pourrait offrir une nouvelle stratégie pour inhiber la réplication du VIH-1. Notre deuxième étude a eu pour but de définir les différentes voies de signalisation activées par le VIH-1. Les changements transcriptionels induits par les différents sous-types du VIH-1 dans les cellules dendritiques immatures ont été examinés par analyse de microréseaux. Nos résultats démontrent que pendant la phase tardive de l'infection VIH-1, un ensemble de gènes est différemment régulé par les différents sous-types du VIH-1. En plus, cette étude accentue le rôle important des cellules dendritiques immatures dans la réplication et la dissémination du VIH-1. En conclusion, étant donné l'importance des RLR dans la reconnaissance des virus à ARN, l'objectif de la dernière étude a été d'étudier les mécanismes d'évasion utilisés par VIH-1 pour contrer la réponse antivirale innée. Nos résultats démontrent que l'ARN du VIH-1 est détecté par le récepteur cytosolique RIG-I. Cependant, une protéine du VIH-1 -la protéase- séquestre le récepteur RIG-I dans les lysosomes et empêche l'activation de la réponse antivirale initié par le récepteur RIG-I. De façon générale, la recherche présentée dans cette thèse propose de nouvelles avenues pour développer des stratégies préventives et thérapeutiques afin de combattre le VIH-1/SIDA.
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Bayer, Ralph C. "The economics of income tax evasion." Thesis, London School of Economics and Political Science (University of London), 2003. http://etheses.lse.ac.uk/2656/.
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This thesis consists of three extended essays on the evasion of income tax. The main purpose of this thesis is to refine the existing tax evasion models in a way that makes it possible to explain empirically established stylized facts that could not be explained before. In the first part we use a standard neoclassical framework in order to analyse the impact of risk preferences on evasion behaviour. We argue that expected value maximization with some fixed and variable costs incurred during the evasion process (moral cost, cost of coverage action etc.) is an appropriate framework to explain the stylised fact that higher tax rates and a higher income lead to more tax evasion. This resolves one of the puzzles concerning tax evasion that was unsolved so far. The second part uses this finding to examine the effect of tax rates on the resources wasted during the process of tax sheltering and evasion detection. We model a declaration detection process, where both, tax inspector and taxpayer, can invest into the probability that the true income from different potential income sources is verified We show that in this contest a higher tax rate leads to more resources that are waste- fully invested in the cat and dog play between authority and taxpayer. The positive effect of rising tax rates and rising income on tax evasion is maintained. The final part of the thesis explains why the tax authority in reality audits sequentially. I.e. it audits single sources at the beginning to conduct a full-scale audit, whenever it finds evidence for irregularities. To do so, we use a simplified version of the model from part two and allow for sequential auditing as well as for different types of taxpayers. The possibility to learn something about the type of the taxpayer by auditing sequentially gives the authority a powerful tool to better target its detection effort. Sequential auditing therefore reduces the amount of non-filers and black market participants as well as the probability that somebody evades a fraction of his total income.
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Vijoen, Janel. "Lessons learnt from history : tax evasion." Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/60529.
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Tax evasion is not a new discovery. The concept of cheating the taxman has been around since the time of the Egyptian Pharaohs. Tax evasion and punishment methods in ancient times, specifically in Egypt, Greece and Rome, are discussed and compared to the history of the native poll tax and the evasion thereof in South African during the 18th century. The tax evasion court case of Al Capone in 1931 laid the foundation for methods such as collaboration between tax authorities and law enforcement agents to investigate charges and convict tax evaders in modern day society. The curbing of tax evasion is a hurdle which governments and policy makers struggle to overcome. This study focuses on establishing whether the rules, legislation and policies implemented by the revenue authorities, for this study, South African Revenue Service, are adequate to prevent tax evasion. Evidence from resent court cases in South Africa and interviews with economic crime offenders serving prison sentences indicated that rules, legislation and policies implemented by the South African Revenue Service, detect and combat tax evasion but do not aim to prevent tax evasion. The reason for this is that rules, legislation and policies do not address the motive for economic crimes. Therefore, it is suggested that the South African Revenue Service adopts a holistic approach towards policy design in order to prevent tax evasion.Mini Dissertation (MCom)--University of Pretoria, 2017.
Taxation
MCom
Unrestricted
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Shabman, Reed Solomon Heise Mark T. "Alphavirus evasion of type I interferons." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2008. http://dc.lib.unc.edu/u?/etd,1879.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2008.Title from electronic title page (viewed Dec. 11, 2008). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Microbiology and Immunology." Discipline: Microbiology and Immunology; Department/School: Medicine.
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Yuwono, Thalyta Ernandya. "Individual income tax in Indonesia behavioral response, incidence, and the distribution of income tax burden /." unrestricted, 2008. http://etd.gsu.edu/theses/available/etd-12122008-223215/.
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Thesis (Ph. D.)--Georgia State University, 2008.Title from file title page. Sally Wallace, committee chair; Jorge L. Martinez-Vazquez, Roy W. Bahl, Robert M. McNab, committee members. Description based on contents viewed June 15, 2009. Includes bibliographical references (p. 113-117).
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Pino, Alcalde Adrián. "Essays on the Spanish Macroeconomy." Doctoral thesis, Universitat Autònoma de Barcelona, 2016. http://hdl.handle.net/10803/399165.
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Esta tesis doctoral intenta arrojar luz en dos temas macroeconomicos de gran
actualidad en la economía española. El diseño del sistema de Seguridad Social,
y la economía sumergida.
En el primer capitulo desarrollo un modelo teórico para estudiar el desempleo en el
ciclo de vida conjuntamente con las decisiones de jubilación, y poder valorar
el impacto que tienen las interacciones entre estas dos políticas a la hora
de plantear posibles alternativas al sistema actual.
El modelo nos permite estudiar efectos en el desempleo, jubilación,
decisiones de ahorro, o la cuantía de las pensiones de cambios de políticas
en la tasa de reemplazo, o modificaciones en la generosidad de los subsidios
de desempleo. Con este modelo busco políticas óptimas en desempleo y jubilación.
La novedad de este artículo es que ante la presencia de desempleo, una tasa
de reemplazo positiva en el sistema de pensiones es óptima. Debido al carácter
heterogéneo de los agentes en el modelo, se puede además medir el impacto que
dichas políticas tienen en la desigualdad.
En el segundo capítulo estudiamos un problema prevalente de la economía española,
la evasión fiscal, extendiendo los modelos macroeconómicos previos de economía
sumergida añadiendo evasión fiscal en los impuestos al consumo. El modelo
presentado es el primero que ataca la evasión del impuesto de la renta y de
los impuestos al consumo de manera conjunta. Las consecuencias de dichas
inclusiones en el modelo son importantes, y descubrimos que ciertas políticas
que parecen factibles sin evasión fiscal pueden no serlo si consideramos
dicho fenómeno. Nuestro marco teórico produce curvas de Laffer en las que
los ingresos tributarios caen de manera importante cuando los tipos impositivos
se elevan por encima de valores muy razonables. Los límites impuestos por la
evasión en el impuesto al consumo/IVA son mucho más estrictos, y se observan
caídas de los ingresos a unos impuestos superiores al 10\%.
en el tercer capítulo extendemos el marco teórico expuesto en el capítulo anterior
y exploramos las propiedades cíclicas de la evasión fiscal. Con una modelización
muy simple de la economía sumergida, y utilizado un shock en la productividad
total de los factores que afecta igualmente al sector legal e ilegal,
somos capaces de producir una evolución contracíclica de la economía sumergida,
hecho que ha sido observado por la literatura empírica. La causa de esto es el
coste de oportunidad en terminos de tiempo que tiene participar en la economía
sumergida, y dicho coste puede no ser asumible en tiempos cuando la productividad
del trabajo es alta.This doctoral thesis tries to shed some light on two topics of current relevance in Spanish macroeconomics. The design of the social insurance system and the problem of tax evasion. In the first chapter I develop a framework to study life cycle unemployment and retirement together, in order to have some foundation on how the interactions between these two phenomena should be taken into account when taking decisions about changing the public social insurance system currently active in Spain. This model allows us to study nontrivial effects on unemployment, retirement decisions, savings and size of PAYG pensions of common policies such as changes in replacement rates in unemployment insurance, or of retirement pensions. I use this framework to find optimal policies in unemployment and retirement. The novelty of this article is that in the presence of unemployment risk, a positive steady state replacement rate in pensions benefits is optimal, together with sizable unemployment benefits. Moreover, this framework is also useful to study the impact that unemployment and retirement policies have on inequality. In the second chapter we look at a prevalent problem of the Spanish economy: tax evasion. We extend previous macroeconomic frameworks on the shadow economy with consumption tax evasion. The model presented here is the first one to jointly tackle tax evasion on both labour income tax and value added/consumption tax. The consequences for taxation of this model are important, and we show that it may be infeasible to implement tax shifts implying significant reductions of income tax in favour of higher excises on consumption. Our model produces Laffer curves in which revenues fall quickly when tax rates are raised above very reasonable levels. The limits imposed by tax evasion are stricter for VAT, for which the \emph{slippery slope} of the Laffer curve starts roughly at a mere rate of 10\%. On the third chapter we extend the theoretical framework of tax evasion and explore the cyclical properties of tax evasion. With a fairly simple modelling of the underground economy, using a TFP shock that affects both the legal an illegal sector symettrically, we are able to produce a countercyclical evolution of the shadow economy, fact that has been pointed out by the empirical literature. The reason is the opportunity cost in terms of time that participating in the underground economy imply, and it may be not worth the trouble at times when the productivity is high.
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Traxler, Christian. "Tax Evasion, Social Norms and Conditional Cooperation." Diss., lmu, 2006. http://nbn-resolving.de/urn:nbn:de:bvb:19-49518.
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Wallin, Marcus. "Carbon dioxide evasion from a boreal catchment /." Uppsala : Sveriges lantbruksuniversitet, 2005. http://info1.ma.slu.se/IMA/Publikationer/internserie/2005-18.pdf.
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Liu, Shih-Yuan. "Collaborative Team Evasion Against a Faster Pursuer." Thesis, University of California, Berkeley, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3686396.
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In the past decade, the level of autonomy of unmanned vehicles has been rising rapidly from remote-controlled towards fully autonomous. Without human operators on board, teams of autonomous vehicles are the best candidates for high risk applications such as search and rescue after disasters and information gathering in hostile environments. For a team of autonomous vehicles to operate effectively in these scenarios, it must be able to respond promptly to environmental hazards and/or hostile entities. In this dissertation, a collaborative team evasion framework is proposed to maximize the survival time of a team of autonomous vehicles against a faster and more agile hostile agent. The proposed framework is based on an open-loop formulation of the single-pursuer-multiple-evader pursuit-evasion game that is conservative to the evaders and provides guarantees on team survival time in the worst-case scenario. An iterative open-loop approach that repeatedly solves the open-loop problem corresponding to the most current state of the game is developed to relax the conservatism of the open-loop formulation and enhance the survival time performance. Extensions to the framework make it possible to take into account the turning rate constraints of the evaders and uncertainties in the position of the pursuer. Numerical approximations are also proposed to reduced the required computation time. Through extensive simulations, the proposed framework is shown to produce reliable strategies for the evaders that result in significantly longer team survival time than previous work in the literature.
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Nava, Mario. "Optimal taxation, tax evasion and rent-seeking." Thesis, London School of Economics and Political Science (University of London), 1996. http://etheses.lse.ac.uk/1436/.
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This thesis is made of five different chapters. Chp 1: OPTIMAL FISCAL AND PUBLIC EXPENDITURE POLICY IN A TWO CLASS ECONOMY This paper deals with optimal taxation and provision of public goods in a two-class economy with non linear income and linear commodity taxes. As far as optimal taxation is concerned, we first show that with two private goods the good complementary with leisure should be taxed more heavily. Second the standard income tax rules are shown to be augmented by considerations for offsetting the distortions created on the commodity markets. As to the provision of public goods we extend recent results for a two class economy with public funds raised entirely by means of a non-linear income tax system. The standard Samuelson rule is modified by two additional terms related to the self selection constraint and to the revenue of indirect taxes. They are both shown to vanish when the agents' utility functions are weakly separable between public and private goods (taken together) and leisure. Chp 2: DIRECT AND INDIRECT TAX EVASION: A SURVEY OF THE LITERATURE The purpose of this selective survey of the literature on both income and commodity tax evasion is to show in which directions, the literature has evolved. Two main approaches are identified for both direct and indirect tax evasion literature. The so-called taxpayer's point of view approach which is basically an exercise of maximization under uncertainty and the so-called tax collector's point of view which is a refinement of the Mirrlees-Stiglitz approach to income taxation and of the Ramsey approach to commodity taxation. The current state of the art is such that both approaches share similar strengths and weaknesses. Chp 3: TAX STRUCTURE, TAX REFORM AND TAX EVASION In this paper we explore whether the shift from an ad valorem tax to a value added tax (which is a prerequisite to join the European Union) improves the "integrity" (number of people in the regular market) and the "efficiency" (total tax revenues) of the tax system. A model of two parallel (black and regular) markets is analyzed. The production in both the black and the regular market is divided in three stages: raw material, intermediate good and final good. Firstly, we prove that if an ad valorem tax is levied, at all stages of the regular market, any, even partial, tax reform towards VAT unequivocally increases integrity (the number of agents). Secondly, we prove that efficiency of the tax system is a direct function of its integrity. Therefore a tax reform from ad valorem to VAT seems justifiable under these two criteria. As a passing result, regular market consumers' welfare is shown to increase. Chp 4. A NOTE ON CORRUPTION, PRODUCTION AND SHORTAGE IN USSR AND RUSSIA Shleifer and Vishny, 1992 argue that privatization increases production and reduces shortage; Komai, 1979 argues that privatization reduces both production and shortage. The transition from USSR to Russia reduced both production and shortage. We argue that this is just the result of the shrinking of the loss-making sector (industrial sector) and the expansion of the profit-making sector (the service sector and namely trade and retailing). We also argue that the validity of Kornai's model is limited to those firms which are overproducing (i.e. more than the profit maximization quantity) and the validity of Shleifer and Vishny's model is limited to those firms which are underproducing. This reconciles two otherwise contradictory papers. Chp 5: LABOUR MARKET REALLOCATION AND RENT-SEEKING IN TRANSITION ECONOMY We present a simple two-sector model of the Russian labour market. Starting from a "full-employment" equilibrium with no search (the USSR), we analyze the path to the new equilibrium with unemployment and search (Russia). The links between the fraction of people searching, the wage differential and the hiring and firing probability of both sectors are investigated. A tentative way to compute these probabilities is proposed starting from recent (91-94) Russian data on unemployment and wages. It is shown that the wage differential across sectors rises with the strengthening of the entry barriers. It is argued that if no action is taken by the Authorities to fight unemployment and to reduce the wage differential across sectors (e.g. relaxing the entry barriers to the most productive sector), the market will react by developing, as an endogenous alternative to unemployment, a third sector which would act as a rent seeking one against the most productive sector. This will increase the outflow of workers from the least productive sector. Finally, it is shown that if the fraction of rent-seeking people attains a critical mass the above-mentioned policies may not be enough to rid the economy of the rent-seeking sector.
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Costello, John Joseph. "Optimizing emergency sortie and storm evasion planning." Thesis, Monterey, California. Naval Postgraduate School, 1993. http://hdl.handle.net/10945/39930.
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Approved for public release; distribution is unlimited.This thesis develops an optimization model for scheduling sorties of surface ships and submarines that are required to plan for port evacuation during hurricane conditions. At present, Emergency Sortie Plans are prepared manually by the Port Operations schedulers and often do not utilize the limited pilot and tug resources most efficiently. The optimization model introduced in this thesis generates an Emergency Sortie Plan that minimizes the time required to reach the recommended Hurricane Evasion Point, evacuates all seaworthy ships, most efficiently utilizes the available pilots and tugs, and observes necessary safety constraints on basin congestion, nested berthing, and tidal-restricted ships. In a test of the model using data for Naval Station Norfolk during Hurricane Andrew, the model evacuated the ships 40 minutes earlier than the actual 11 hour schedule. In only 22 minutes on a personal computer the model provided a realistic estimate of the minimum time required to complete an Emergency Sortie, based on known information, not educated guesses.
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Mishkov, Lyubomir Rumenov. "Informal entrepreneurship and tax evasion in Bulgaria." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/18685/.
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Purpose: Tackling large informal economies is particularly challenging due to their self-perpetuating nature and complex participatory motivations. This thesis reveals the strongest determinants of business tax evasion, suggesting new evidence for more adequate policy approaches. Literature: The institutional asymmetry paradigm (IAP), adopted in this study, poses specific empirical challenges. Indeed, how to measure empirically the intrinsic circularity between tangible and intangible phenomena, affecting tax evasive behaviour. The contribution to the literature debates is through appraisal of these issues, proposing an economic model of partly informal entrepreneurship. Research aims: The main research aim is to develop a holistic account of the socio-economic influencers of the processes of tax evasion and (in)formalisation. A comprehensive review of tax policy management has been conducted, exposing the three major environmental pressures (institutional, economic and political) on Bulgaria's National Revenue Agency (NRA). It has been studied how institutional quality, procedural fairness and distributive justice transform into tangible economic effects on small businesses' evasive behaviour. Methodology: Mixed methods in exploratory sequential design. The in-depth semi-structured interviews with key NRA officials have been supplementary analysed with NVivo and IBM SPSS Modeler for increased findings' objectivity. This informed a quantitative questionnaire to investigate entrepreneurs' informal tactics. Utilising proven multi-disciplinary methods (Decision trees, Neural and Bayesian networks), the study advances an innovative predictive socio-economic profiling of business tax evaders. Findings and contributions: Operating in the most challenging EU economic environment, Bulgaria's NRA experiences political influence for asymmetrical tax gap closure, which leads to unjustifiable regulative formalism within an outdated deterrence orientated approach. 76.5% of the entrepreneurs evade taxes due to unfair competition ensuing survivalist reasoning. Evidently, the informal economy share is much higher than current macro-measurement methods report (31.2% of GDP). These tough policy challenges could be tackled only through inducing financially and socially efficient voluntary tax compliance.
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Hagen, Johannes. "Essays on Pensions, Retirement and Tax Evasion." Doctoral thesis, Uppsala universitet, Nationalekonomiska institutionen, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-274479.
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Essay I: This essay provides an overview of the history of the Swedish pension system. Starting with the implementation of the public pension system in 1913, it outlines the key components of each major pension reform up until today along with a discussion of the main trade-offs and concerns that policy makers have faced. It also describes the historical background of the four largest occupational pension plans in Sweden and the mutual influence between these plans and the public pension system. Essay II: Despite the fact that the increasing involvement of the private sector in pension provision has brought more flexibility to the pay-out phase of retirement, little is known about the characteristics of those who choose to annuitize their pension wealth and those who do not. I combine unique micro-data from a large Swedish occupational pension plan with rich national administrative data to study the choice between life annuities and fixed-term payouts with a minimum payout length of 5 years for 183,000 retiring white-collar workers. I find that low accumulation of assets is strongly associated with the choice of the 5-year payout. Consistent with individuals selecting payout length based on private information about their mortality prospects, individuals who choose the 5-year payout are in worse health, exhibit higher ex-post mortality rates and have shorter-lived parents than annuitants. Individuals also seem to respond to large, tax-induced changes in annuity prices. Essay III: This essay estimates the causal effect of postponing retirement on a wide range of health outcomes using Swedish administrative data on cause-specific mortality, hospitalizations and drug prescriptions. Exogenous variation in retirement timing comes from a reform which raised the age at which broad categories of Swedish local government workers were entitled to retire with full pension benefits from 63 to 65. The reform caused a remarkable shift in the retirement distribution of the affected workers, increasing the actual retirement age by more than 4.5 months. Instrumental variable estimation results show no effect of postponing retirement on the overall consumption of health care, nor on the risk of dying early. There is evidence, however, of a reduction in diabetes-related hospitalizations and in the consumption of drugs that treat anxiety. Essay IV (with Per Engström): The consumption based method to estimate underreporting among self-employed, introduced by Pissarides and Weber (1989), is one of the workhorses in the empirical literature on tax evasion/avoidance. We show that failure to account for transitory income fluctuations in current income may overestimate the degree of underreporting by around 40 percent. Previous studies typically use instrumental variable methods to address the issue. In contrast, our access to registry based longitudinal income measures allows a direct approach based on more permanent income measures. This also allows us to evaluate the performance of a list of instruments widely used in the previous literature. Our analysis shows that capital income is the most suitable instrument in our application, while education and housing related measures do not seem to satisfy the exclusion restrictions.
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Sengupta, Partha. "Essays on the theory of tax evasion." Diss., Virginia Tech, 1991. http://hdl.handle.net/10919/39419.
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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, fIrrns 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.
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Ben-Asher, Joseph Z. "Optimal evasion against a proportionally guided pursuer." Thesis, Virginia Tech, 1986. http://hdl.handle.net/10919/51126.
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We consider the problem of optimal evasion when the pursuer is known to employ fixed gain proportional navigation . The performance index is a measure of closest approach. The analysis is done for planar motions at constant speed. The kinematics are first linearized around a nominal collision course. The dynamics of the opponents are modeled by first order systems and their accelerations may be bounded.
Three cases are studied: unconstrained optimal evasion (where the evader is not subjected to any path constraint) against a single pursuer, optimal evasion with a terminal path angle constraint for the evader and optimal evasion against more than one pursuer.
The optimal controls are shown to be 'bang - bang' with the number of switches depending on the pursuer’s navigation gain and on the particular constraints of each case.Master of Science
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LIPATOV, Vilen. "Tax evasion and avoidance : game theoretic approach." Doctoral thesis, European University Institute, 2007. http://hdl.handle.net/1814/10309.
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Defence date: 5 September 2007Examining Board: Pascal Courty, (European University Institute) ; Chaim Fershtman, (The Eitan Berglas School of Economics, Tel-Aviv University) ; Ronny Razin, (London School of Economics) ; Karl Schlag, (European University Institute)
PDF of thesis uploaded from the Library digital archive of EUI PhD theses
no abstract available
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Souza, Thays Santos. "Estudo sobre a evasão em cursos de graduação presenciais na Universidade Federal de Goiás - UFG." Universidade Federal de Goiás, 2017. http://repositorio.bc.ufg.br/tede/handle/tede/8125.
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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.
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Eichhorn, Christoph. "Optimal Policies in the Presence of Tax Evasion." Diss., lmu, 2006. http://nbn-resolving.de/urn:nbn:de:bvb:19-55862.
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Vyboh, Kishanda. "Mapping HIV-1's evasion of host defense." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110455.
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The HIV-1 RNA genome encodes the main structural polyprotein Gag, Gag/Pol (structural proteins and enzymes), auxiliary (Vpr, Vpu, Vif) and regulatory proteins (Tat, Rev, Nef). The expression of the full complement of viral gene products enhances both the replication and the pathogenic potential of the virus. In our previous work we showed that HIV-1 expression prevented eIF2alpha-dependent stress granule (SG) assembly in cells. SGs are translationally silent sites of RNA triage and can be readily visualized in cells due to clustering of cytoplasmic RNA and the recruitment of multiple cytoplasmic proteins (e.g., TIA/R, G3BP and eIF3). In this work, we attempted to understand how HIV-1 blocks SG formation and defined the determinant in HIV-1 that mediates this. To initiate SG assembly, the drug Pateamine A was used. Pateamine A causes an activation of eIF4A, which will lead to a disassembly of the eIF4F complex and an arrest in translation all in an eIF2alpha-independent manner. To identify the responsible gene, proviral constructs with individually deleted auxiliary and regulatory viral genes were expressed in HeLa cells. Among the proviral deletion constructs tested, two were found to be unable to block SG assembly: pNLXX, and Rev-. Both of these constructs share one important similarity in that they all do not express the main structural protein Gag due either to the presence of premature stop codons (pNLXX) or the nuclear retention of the genomic RNA that encodes Gag (Rev-). To directly test the hypothesis that the Gag polyprotein alone blocks stress granule assembly, we transfected cells with various mammalian expression constructs of Gag. These all prevented SG assembly. We went on to further map the responsible domain of Gag to the N-terminus of the Capsid domain, specifically to two amino acids. In conclusion, HIV-1 Gag prevents SG assembly via the N-terminus of Capsid and may confer to the virus a replicative advantage during times of stress.Le génome du virus de l'immunodéficience humaine 1 (VIH-1) comprend les protéines structurales principales Gag, Gag/Pol (structurale et enzymatique), auxiliaires (Vpr, Vpu, Vif) et régulatrices (Tat, Rev, Nef). L'expression de toutes ces protéines virales augmente la réplication et le potentiel pathogène du virus. Nos résultats précédents montrent que l'assemblage des granules de stress par un processus dépendant de eIF2alpha peut être bloqué par l'expression des gènes du VIH-1. Les granules de stress sont des sites de triage d'ARN sans traduction et elles peuvent être visualisées grâce à l'accumulation d'ARN cytoplasmique et au recrutement de plusieurs protéines cytoplasmiques (TIA/R, G3BP and eIF3, par exemple). Les résultats présentés ici montrent comment le VIH-1 empêche la formation des granules de stress et caractérisent les facteurs impliqués dans ce processus. Pour provoquer la formation de granules de stress, le composé Pateamine A a été utilisé. Pateamine A cause l'activation de eIF4A, qui provoque la dissolution du complexe eIF4F et arrête la traduction par un processus indépendant de eIF2alpha. Pour identifier le gène du VIH qui empêche la formation de granules de stress, des constructions provirales individuellement déficientes dans un gène auxiliaire ou régulateur ont été exprimées dans des cellules HeLa. Parmi les constructions provirales testées, deux étaient incapables de prévenir la formation de granules de stress: pNLXX, et Rev-. Ces deux constructions ne peuvent pas exprimer la protéine structurale Gag, soit à cause de la présence de codons stop prématurés (pNL-XX), soit à cause de la rétention dans le noyau de l'ARN viral codant pour Gag (Rev-). Pour déterminer si la polyprotéine Gag est suffisante pour empêcher la formation de granules de stress, des cellules HeLa ont été transfectées avec plusieurs différents vecteurs exprimant Gag. Tous ont empêché la formation de granules de stress. De plus, nous avons déterminé que l'extrémité N-terminale du domaine de Capside de Gag est responsable de cette inhibition. En particulier, l'activité anti-granules de stresse réside dans deux acides aminés. Ainsi, la protéine Gag du VIH-1 empêche la formation de granules de stress via l'extrémité N-terminale de la Capside et pourrait donner au virus un avantage réplicatif dans des conditions de stress.
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Chan, Mei-po, and 陳美寶. "Modulation of Bacillus Calmétte Guerin-induced immune evasion." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B40987607.
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Tajdini, M. "Developing an advanced IPv6 evasion attack detection framework." Thesis, Liverpool John Moores University, 2018. http://researchonline.ljmu.ac.uk/9864/.
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Internet Protocol Version 6 (IPv6) is the most recent generation of Internet protocol. The transition from the current Internet Version 4 (IPv4) to IPv6 raised new issues and the most crucial issue is security vulnerabilities. Most vulnerabilities are common between IPv4 and IPv6, e.g. Evasion attack, Distributed Denial of Service (DDOS) and Fragmentation attack. According to the IPv6 RFC (Request for Comment) recommendations, there are potential attacks against various Operating Systems. Discrepancies between the behaviour of several Operating Systems can lead to Intrusion Detection System (IDS) evasion, Firewall evasion, Operating System fingerprint, Network Mapping, DoS/DDoS attack and Remote code execution attack. We investigated some of the security issues on IPv6 by reviewing existing solutions and methods and performed tests on two open source Network Intrusion Detection Systems (NIDSs) which are Snort and Suricata against some of IPv6 evasions and attack methods. The results show that both NIDSs are unable to detect most of the methods that are used to evade detection. This thesis presents a detection framework specifically developed for IPv6 network to detect evasion, insertion and DoS attacks when using IPv6 Extension Headers and Fragmentation. We implemented the proposed theoretical solution into a proposed framework for evaluation tests. To develop the framework, "dpkt" module is employed to capture and decode the packet. During the development phase, a bug on the module used to parse/decode packets has been found and a patch provided for the module to decode the IPv6 packet correctly. The standard unpack function included in the "ip6" section of the "dpkt" package follows extension headers which means following its parsing, one has no access to all the extension headers in their original order. By defining, a new field called all_extension_headers and adding each header to it before it is moved along allows us to have access to all the extension headers while keeping the original parse speed of the framework virtually untouched. The extra memory footprint from this is also negligible as it will be a linear fraction of the size of the whole set of packet. By decoding the packet, extracting data from packet and evaluating the data with user-defined value, the proposed framework is able to detect IPv6 Evasion, Insertion and DoS attacks. The proposed framework consists of four layers. The first layer captures the network traffic and passes it to second layer for packet decoding which is the most important part of the detection process. It is because, if NIDS could not decode and extract the packet content, it would not be able to pass correct information into the Detection Engine process for detection. Once the packet has been decoded by the decoding process, the decoded packet will be sent to the third layer which is the brain of the proposed solution to make a decision by evaluating the information with the defined value to see whether the packet is threatened or not. This layer is called the Detection Engine. Once the packet(s) has been examined by detection processes, the result will be sent to output layer. If the packet matches with a type or signature that system admin chose, it raises an alarm and automatically logs all details of the packet and saves it for system admin for further investigation. We evaluated the proposed framework and its subsequent process via numerous experiments. The results of these conclude that the proposed framework, called NOPO framework, is able to offer better detection in terms of accuracy, with a more accurate packet decoding process, and reduced resources usage compared to both exciting NIDs.
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Abdixhiku, Lumir. "Determinants of business tax evasion in transition economies." Thesis, Staffordshire University, 2013. http://eprints.staffs.ac.uk/1962/.
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Tax evasion represents one of the major problems facing transition and developing economies. It imposes several economic costs: it slows down economic growth; it diverts resources to unproductive activities; it provides an incentive for firms to remain small and invisible; and it generates inequity between the evaders and the honest taxpayers. The aim of this thesis is to investigate the determinants of business tax evasion for transition economies. We do so by adapting the individual theory to the case of businesses; that is by assuming that the behaviour of businesses is similar to the behaviour of individuals, and that the determinants of business tax evasion may be similar, at least qualitatively, to the determinants of tax evasion by individuals or households. More specifically, beyond theoretical and empirical review of the tax evasion literature, this thesis provides three related empirical investigations: a panel investigation of tax evasion at the country level; a pooled-cross section investigation of firm-level behaviour across the transition economies and a cross-section investigation of business tax evasion and tax morale in Kosovo. For the firm-level investigation we use the BEEPS data for the years 1999, 2002 and 2005; and, for the investigation of business tax evasion in Kosovo, we generate primary data by developing a questionnaire and conducting a survey of businesses in Kosovo. Our econometric findings suggest that, first, regardless of the theoretical and previous empirical ambiguity, when it comes to transition economies the relationship between tax rate and tax evasion is positive; second, the macroeconomic environment has only minor effects on business tax evasion, suggesting that the decision to evade or not must depend on other non-economic factors; third, even if a country is performing well in general economic terms, the presence of negative institutional phenomena exert a dominant and immediate influence on the relationship between businesses and government; fourth, business tax morale, as is the case with individuals, has a strong and negative relationship with tax evasion; fifth, moreover, given that the same considerations on morality apply to both individuals and businesses, policies in the individual context apply also to businesses; sixth, lower corruption, higher trust and better treatment of business taxpayers improves significantly both tax morale and tax compliance; and, seventh, because levels of tax evasion vary across firm characteristics, audit strategies should be set accordingly. Finally this thesis provides a set of corresponding policy recommendations intended to reduce either the possibility and/or the inclination to evade.
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Soares, Ronan Pardo. "Pursuit-evasion games, decompositions and convexity on graphs." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=11105.
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CoordenaÃÃo de AperfeiÃoamento de NÃvel SuperiorEsta tese à centrada no estudo de propriedades estruturais de grafos cujas compressÃes permitem a concepÃÃo de algoritmos eficientes para resolver problemas de otimizaÃÃo. Estamos particularmente interessados em decomposiÃÃes, em jogos de perseguiÃÃo-evasÃo e em convexidade. O jogo de Processo foi definido como um modelo para a reconfiguraÃÃo de roteamento em redes WDM. Muitas vezes, jogos de perseguiÃÃo-evasÃo, em que uma equipe de agentes tem como objetivo limpar um grafo nÃo direcionado, estÃo intimamente relacionados com decomposiÃÃes em grafos. No caso de grafos direcionados, mostramos que o jogo de Processo à monotÃnico e definimos uma nova decomposiÃÃo em grafos equivalente a tal jogo. A partir de entÃo, investigamos outras decomposiÃÃes em grafos. Propomos um algoritmo FPT para calcular vÃrios parÃmetros de largura em grafos. Em particular, este à o primeiro algoritmo FPT para calcular a largura em Ãrvore especial e a largura em Ãrvore q-ramificada de um grafo. Em seguida, estudamos um outro jogo perseguiÃÃo-evasÃo que modela problemas de prÃ-obtenÃÃo. NÃs introduzimos uma versÃo mais realista do jogo de VigilÃncia a versÃo on-line. Estudamos a diferenÃa entre o jogo de VigilÃncia clÃssico e suas versÃes conectadas e on-line, fornecendo novos limites para essa diferenÃa. NÃs, entÃo, definimos um modelo geral para o estudo de jogos perseguiÃÃo-evasÃo, com base em tÃcnicas de programaÃÃo linear. Este mÃtodo permite-nos dar os primeiros resultados de aproximaÃÃo para alguns desses jogos. Finalmente, estudamos outro parÃmetro relacionado com a convexidade e a propagaÃÃo da infecÃÃo em redes, o âhull numberâ. NÃs fornecemos vÃrios resultados de complexidade computacional, dependendo das propriedades estruturais do grafo de entrada e usando decomposiÃÃes em grafos. Alguns destes resultados respondem problemas em aberto na literatura.
This thesis focuses on the study of structural properties of graphs whose understanding enables the design of efficient algorithms for solving optimization problems. We are particularly interested in methods of decomposition, pursuit-evasion games and the notion of convexity. The Process game has been defined as a model for the routing reconfiguration problem in WDM networks. Often, such games where a team of searchers have to clear an undirected graph are closely related to graph decompositions. In digraphs, we show that the Process game is monotone and we define a new equivalent digraph decomposition. Then, we further investigate graph decompositions. We propose a unified FPT-algorithm to compute several graph width parameters. This algorithm turns to be the first FPTalgorithm for the special and the q-branched tree-width of a graph. We then study another pursuit-evasion game which models prefetching problems. We introduce the more realistic online variant of the Surveillance game. We investigate the gap between the classical Surveillance Game and its connected and online versions by providing new bounds. We then define a general framework for studying pursuit-evasion games, based on linear programming techniques. This method allows us to give first approximation results for some of these games. Finally, we study another parameter related to graph convexity and to the spreading of infection in networks, namely the hull number. We provide several complexity results depending on the graph structures making use of graph decompositions. Some of these results answer open questions of the literature.
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Andrews, Sophie Marie. "Adaptive immune evasion in clinically latent HIV infection." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:b7416aab-d345-48df-9194-797c62d7db47.
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HIV is a master of immune evasion, utilising a range of different techniques to not only survive the human immune system, but also mediate its eventual catastrophic decline. Understanding how HIV evades the adaptive immune response is paramount to developing effective treatments and vaccines. This thesis aimed to investigate three key ways in which HIV-1 and HIV-2 mediate immune evasion in the context of clinically latent infection. Chapter three summarises a study into selection pressure and mutation in the gp120 envelope gene in a narrow-source HIV-1 cohort of former plasma donors (FPDs) from China. This study further characterised the cohort, and identified specific mutations in the gene consistent with antibody and CTL-driven selection pressure. Chapter four describes an investigation into the downregulation of HLA-I mediated by primary isolates of HIV-1 and HIV-2 Nef. Nef-mediated HLA-I downregulation contributes to the evasion of CTL responses. In stark contrast to previous reports, no evidence for differential downregulation of HLA-A and HLA-B was detected, but primary isolates invariably showed reduced activity relative to laboratory-adapted and consensus variants. In performing this study, a number of limitations came to light regarding how bifurcate analyses are used to interpret flow cytometric data collected in studies of receptor modulation. A novel technique - SWARM - was therefore developed to address these limitations, and is described in chapter five. Chapter six aimed to address why CTL responses against HIV-2 Nef are rare, despite HIV-1 Nef being highly immunogenic. A series of in vitro (immuno)proteasomal processing assays revealed HIV-2 Nef is more extensively digested than HIV-1 Nef, but further experimentation is required to explain the difference in response. Finally, chapter seven briefly summarises a successful collaborative attempt to resolve the first ever crystal structure of HIV-2 Nef.
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Mittone, Luigi. "Psychological constraints on tax evasion : an experimental approach." Thesis, University of Bristol, 1999. http://hdl.handle.net/1983/01646806-1188-4508-867f-3703f32dd2c9.
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Ozturk, Mumin. "Tuberculosis transcriptomics: host protection and immune evasion mechanisms." Doctoral thesis, University of Cape Town, 2017. http://hdl.handle.net/11427/26863.
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Mycobacterium tuberculosis (Mtb) is the leading cause of death from an infectious disease. The success of the pathogen lies in its ability to subvert hostile intracellular macrophage environment. We performed genome-wide transcriptional deep sequencing on total RNA in murine bone marrow-derived macrophages (BMDM) infected with hypervirulent Beijing strain (HN878) in an extensive time kinetic manner using single molecule sequencer and cap analysis gene expression (CAGE) technique. CAGE analysis revealed nearly 36000 unique RNA transcripts with approximately 16000 are not unannotated to a specific gene. This thesis addressed global changes in RNA expression levels in macrophages infected with Mtb in a time kinetic manner to pinpoint novel host protection and immune evasion genes and elucidate the role of these genes in vitro macrophage assays and in vivo knockout mouse studies. The data in this thesis showed that basic leucine zipper transcription factor 2 (Batf2) was an important factor that regulates inflammatory responses in Mtb infection. Deletion of Batf2 led to the survival of mice with reduced lung inflammation and histopathology due to reduced recruitment of inflammatory macrophages. We also showed that Batf2 was highly expressed in peripheral blood from adolescents who progressed from infection to tuberculosis disease and a predictive human biomarker for tuberculosis disease. In contrast to Batf2, we showed that Protein Kinase C-delta (PKC-δ) deficient mice are highly susceptible to tuberculosis and human lung proteomics dataset revealed that PKC-δ was highly upregulated in the necrotic and cavitory regions of human granulomas in multi-drug resistant subjects. PKC-δ deficient mice had a significant reduction in alveolar macrophages and dendritic cells, reduced accumulation of lipid bodies and serum fatty acids. In vitro experiments showed that PKCδ was required for optimal killing effector functions which were independent of phagosome maturation and autophagy in primary murine macrophages. Our studies suggested that these novel genes play a role in the immune response to Mtb and should be studied more thoroughly to evaluate their potential in possible TB interventions.
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Benting, Jade. "Business rescue as a vehicle for tax evasion." Diss., University of Pretoria, 2019. http://hdl.handle.net/2263/76932.
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Prasad, Deepika. "Pursuit Evasion From Multiple Pursuers Using Speed Fluctuation." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1367928486.
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Davis, Meredith Elizabeth. "Evasion of MDA5-Mediated Innate Immunity by Paramyxoviruses." Thesis, Harvard University, 2015. http://nrs.harvard.edu/urn-3:HUL.InstRepos:17467328.
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The innate immune sensor MDA5, a RIG-I-like receptor (RLR), is critical for the detection of viral nucleic acid, eliciting an antiviral immune response. Aberrant immune activation can be detrimental to the host; therefore, RLR activity is strictly regulated. In the uninfected cell, MDA5 is constitutively phosphorylated at S88, preventing antiviral signaling. Upon sensing of viral RNA, MDA5 is activated via dephosphorylation by the phosphatases PP1a/c. Dephosphorylation of MDA5 allows interaction with the mitochondrial adaptor protein MAVS, inducing downstream signaling, leading to the production of antiviral cytokines including type-I interferons (IFNs). Many viruses have evolved sophisticated mechanisms to avoid detection by RLRs. Here, we present a novel evasion mechanism of paramyxoviruses to escape the MDA5-induced innate immune response: inhibition of its key regulators, PP1a and PP1c. The V proteins of measles virus (MV) and multiple other paramyxoviruses interact with PP1a/c, preventing MDA5 S88 dephosphorylation and subsequent innate immune signaling.
In Chapter 2, we identify a conventional PP1-binding motif in the unique C-terminal region of the MV V protein which mediates this interaction. Mutation of this motif abrogates PP1 binding and MDA5 antagonism without effecting other known activities of the V protein such as STAT inhibition. To determine the physiological relevance of the V-PP1 interaction for MDA5 antagonism, we generated a recombinant MV carrying a PP1-binding deficient V protein. This mutant virus no longer suppressed MDA5 dephosphorylation by PP1, resulting in increased expression of IFN and IFN-stimulated genes (ISGs) and impaired replication in lung epithelial and dendritic cells compared to the parental virus.
In Chapter 3, we expand our understanding of paramyxovirus antagonism of MDA5 by examining the virus-specificity of inhibition of S88 dephosphorylation. We found that the ability to interact with PP1 and inhibit MDA5 S88 dephosphorylation is shared by multiple viruses, including mumps (MuV), Nipah, and Hendra viruses. We mapped the PP1 interaction to a minimal binding region in the MuV-V C-terminal domain. This region contains a putative PP1-binding motif which is not conserved between viruses. The importance of this putative motif requires additional investigation. Together, our findings reveal PP1 antagonism as a novel immune evasion strategy of paramyxoviruses.Medical Sciences
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Chan, Mei-po. "Modulation of Bacillus Calmétte Guerin-induced immune evasion." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/hkuto/record/B40987607.
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Lu, Gen. "Analysis of Evasion Techniques in Web-based Malware." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/312567.
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Web-based mechanisms, often mediated by malicious JavaScript code, play an important role in malware delivery today, making defenses against web-based malware crucial for system security. To make it even more challenging, malware authors often take advantage of various evasion techniques to evade detection. As a result, a constant arms race of evasion and detection techniques between malware authors and security analysts has led to advancement in code obfuscation and anti-analysis techniques. This dissertation focuses on the defenses against web-based malware protected by advanced evasion techniques from both defensive and offensive perspectives. From a defensive perspective, we examine existing evasion techniques and propose deobfuscation and detection approaches to defeating some popular techniques used by web-based malware today. In the case of code-unfolding based obfuscation, we use a semantics-based approach to simplify away obfuscations by identifying code that is relevant to the behavior of the original program. In the case of environment-dependent malware, we propose environmental predicate, which detects behavior discrepancy of JavaScript program between targeted browser and detector sandbox, therefore protecting users from possible detection false negatives caused by environmental triggers. From an offensive perspective, we analyze existing detection techniques to examining their assumptions and study how these assumptions can be broken. We also propose a combination of obfuscation and anti-analysis techniques, targeting these limitations, which can hide existing web-based malware from state-of-the-art detectors.
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WANG, Yiqun. "Competition and tax evasion : a cross country study." Digital Commons @ Lingnan University, 2009. https://commons.ln.edu.hk/econ_etd/8.
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This paper investigates the determinants of informality (tax evasion in particular) utilizing rich cross-country data of firm-level survey from the World Bank, and hypothesizing that competition is a significant factor determining tax evasion behaviors. Competition pressure is a key stimulus to induce questionable manipulations of tax reporting behaviors. However its effect works at a decreasing speed. It is also hypothesized that business obstacles facing firms such as tax administration and corruption play significant roles in explaining tax evasion. This paper further hypothesizes that firm characteristics such as size, age, ownership are important evasion determinants. Empirical results are found supporting these hypotheses above. The analysis controls for country-level effects, for instance the quality of the legal environment. Industry sectors are also controlled and found significant in explaining corporate tax evasion levels.
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GIUSSANI, STEFANIA. "Mechanisms of Complement evasion in Group B Streptococcus." Doctoral thesis, Università degli studi di Pavia, 2019. http://hdl.handle.net/11571/1248526.
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GIUSSANI, STEFANIA. "Mechanisms of Complement evasion in Group B Streptococcus." Doctoral thesis, Università degli studi di Pavia, 2019. http://hdl.handle.net/11571/1263953.
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GIUSSANI, STEFANIA. "Mechanisms of Complement evasion in Group B Streptococcus." Doctoral thesis, Università degli studi di Pavia, 2019. http://hdl.handle.net/11571/1264013.
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GIUSSANI, STEFANIA. "Mechanisms of Complement evasion in Group B Streptococcus." Doctoral thesis, Università degli studi di Pavia, 2019. http://hdl.handle.net/11571/1263915.
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GIUSSANI, STEFANIA. "Mechanisms of Complement evasion in Group B Streptococcus." Doctoral thesis, Università degli studi di Pavia, 2019. http://hdl.handle.net/11571/1264035.
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GIUSSANI, STEFANIA. "Mechanisms of Complement evasion in Group B Streptococcus." Doctoral thesis, Università degli studi di Pavia, 2019. http://hdl.handle.net/11571/1248546.
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GIUSSANI, STEFANIA. "Mechanisms of Complement evasion in Group B Streptococcus." Doctoral thesis, Università degli studi di Pavia, 2019. http://hdl.handle.net/11571/1263975.
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GIUSSANI, STEFANIA. "Mechanisms of Complement evasion in Group B Streptococcus." Doctoral thesis, Università degli studi di Pavia, 2019. http://hdl.handle.net/11571/1263893.
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GIUSSANI, STEFANIA. "Mechanisms of Complement evasion in Group B Streptococcus." Doctoral thesis, Università degli studi di Pavia, 2019. http://hdl.handle.net/11571/1265353.
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