32 research outputs found

    Mathematical Modeling and Analysis of Epidemiological and Chemical Systems

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    This dissertation focuses on three interdisciplinary areas of applied mathematics, mathematical biology/epidemiology, economic epidemiology and mathematical physics, interconnected by the concepts and applications of dynamical systems.;In mathematical biology/epidemiology, a new deterministic SIS modeling framework for the dynamics of malaria transmission in which the malaria vector population is accounted for at each of its developmental stages is proposed. Rigorous qualitative and quantitative techniques are applied to acquire insights into the dynamics of the model and to identify and study two epidemiological threshold parameters reals* and R0 that characterize disease transmission and prevalence, and that can be used for disease control. It is shown that nontrivial disease-free and endemic equilibrium solutions, which can become unstable via a Hopf bifurcation exist. By incorporating vector demography; that is, by interpreting an aspect of the life cycle of the malaria vector, natural fluctuations known to exist in malaria prevalence are captured without recourse to external seasonal forcing and delays. Hence, an understanding of vector demography is necessary to explain the observed patterns in malaria prevalence. Additionally, the model exhibits a backward bifurcation. This implies that simply reducing R0 below unity may not be enough to eradicate the malaria disease. Since, only the female adult mosquitoes involved in disease transmission are identified and fully accounted for, the basic reproduction number (R0) for this model is smaller than that for previous SIS models for malaria. This, and the occurrence of both oscillatory dynamics and a backward bifurcation provide a novel and plausible framework for developing and implementing optimal malaria control strategies, especially those strategies that are associated with vector control.;In economic epidemiology, a deterministic and a stochastic model are used to investigate the effects of determinism, stochasticity, and safety nets on disease-driven poverty traps; that is, traps of low per capita income and high infectious disease prevalence. It is shown that economic development in deterministic models require significant external changes to the initial economic and health care conditions or a change in the parametric structure of the system. Therefore, poverty traps arising from deterministic models lead to more limited policy options. In contrast, there is always some probability that a population will escape or fall into a poverty trap in stochastic models. It is demonstrated that in stochastic models, a safety net can guarantee ultimate escape from the poverty trap, even when it is set within the basin of attraction of the poverty trap or when it is implemented only as an economic or health care intervention. It is also shown that the benefits of safety nets for populations that are close to the poverty trap equilibrium are highest for the stochastic model and lowest for the deterministic model. Based on the analysis of the stochastic model, the following optimal economic development and public health intervention questions are answered: (i) Is it preferable to provide health care, income/income generating resources, or both health care and income/income generating resources to enable populations to break cycles of poverty and disease; that is, escape from poverty traps? (ii) How long will it take a population that is caught in a poverty trap to attain economic development when the initial health and economic conditions are reinforced by safety nets?;In mathematical physics, an unusual form of multistability involving the coexistence of an infinite number of attractors that is exhibited by specially coupled chaotic systems is explored. It is shown that this behavior is associated with generalized synchronization and the emergence of a conserved quantity. The robustness of the phenomenon in relation to a mismatch of parameters of the coupled systems is studied, and it is shown that the special coupling scheme yields a new class of dynamical systems that manifests characteristics of dissipative and conservative systems

    Whistleblowing for Change

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    The courageous acts of whistleblowing that inspired the world over the past few years have changed our perception of surveillance and control in today's information society. But what are the wider effects of whistleblowing as an act of dissent on politics, society, and the arts? How does it contribute to new courses of action, digital tools, and contents? This urgent intervention based on the work of Berlin's Disruption Network Lab examines this growing phenomenon, offering interdisciplinary pathways to empower the public by investigating whistleblowing as a developing political practice that has the ability to provoke change from within

    Whistleblowing for Change

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    The courageous acts of whistleblowing that inspired the world over the past few years have changed our perception of surveillance and control in today's information society. But what are the wider effects of whistleblowing as an act of dissent on politics, society, and the arts? How does it contribute to new courses of action, digital tools, and contents? This urgent intervention based on the work of Berlin's Disruption Network Lab examines this growing phenomenon, offering interdisciplinary pathways to empower the public by investigating whistleblowing as a developing political practice that has the ability to provoke change from within

    Love, Sex, and the Noose: The Emotions of Sodomy in 18th-Century England

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    At the end of the 19th century, it was believed that men who desired other men were \u27despicable, degraded, depraved, vicious, and incapable of humane and generous sentiments\u27. This dissertation examines how the emotional reactions of and towards sodomites in England between 1691 and 1828 shaped this perception. It considers six sets of paired emotions: lust and disgust, love and hatred, hope and fear, gratitude and anger, joy and sadness, and pride and shame. It examines how changes in law, gender norms, in religious and philosophical thought, the rise of sentimentalism, evangelism, nationalism and the middle-class shaped these emotional reactions. This dissertation is interdisciplinary, with secondary sources from literature, philosophy, religion, gender studies, sociology, law and psychology. The first chapter shows how understandings of desire became tied to nature and reason, and so the ‘unnatural’ became the target of moral disgust. This re-framing of desire also rooted love in marriage and domesticity. This same process was used to justify hatred and violence towards sodomites. The third chapter considers the emotions of hope, fear, gratitude and anger. Fear of sodomites was used to justify anger against them; living in constant fear made hope difficult, leading to sadness and despair; sodomy was also held out as ungrateful to women and to God. Sentimentalism and evangelism led to the conflation of happiness to the presence and influence of women, excluding sodomites. Finally, the shame created and enforced through disgust, hatred and disgrace became internalized by the 19th century

    Elementary approaches to microbial growth rate maximisation

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    This thesis, called Elementary approaches to microbial growth rate maximisation, reports on a theoretical search for principles underlying single cell growth, in particular for microbial species that are selected for fast growth rates. First, the optimally growing cell is characterised in terms of its elementary modes. We prove an extremum principle: a cell that maximises a metabolic rate uses few Elementary Flux Modes (EFMs, the minimal pathways that support steady-state metabolism). The number of active EFMs is bounded by the number of growth-limiting constraints. Later, this extremum principle is extended in a theory that explicitly accounts for self-fabrication. For this, we had to define the elementary modes that underlie balanced self-fabrication: minimal self-supporting sets of expressed enzymes that we call Elementary Growth Modes (EGMs). It turns out that many of the results for EFMs can be extended to their more general self-fabrication analogue. Where the above extremum principles tell us that few elementary modes are used by a rate-maximising cell, it does not tell us how the cell can find them. Therefore, we also search for an elementary adaptation method. It turns out that stochastic phenotype switching with growth rate dependent switching rates provides an adaptation mechanism that is often competitive with more conventional regulatory-circuitry based mechanisms. The derived theory is applied in two ways. First, the extremum principles are used to review the mathematical fundaments of all optimisation-based explanations of overflow metabolism. Second, a computational tool is presented that enumerates Elementary Conversion Modes. These elementary modes can be computed for larger networks than EFMs and EGMs, and still provide an overview of the metabolic capabilities of an organism

    "Nec tecum nec sine te" : Language-Music Interplays in Musical Responses to Samuel Beckett

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    Intermediality is rarely a one-way street: Throughout his career, Samuel Beckett employed a variety of modes of expression and media in his works, and – vice versa – it is partly owing to the strong role played by music in his works that Samuel Beckett's works figure so prominently in compositional history from 1930 to the present day. In fact, with more than 250 Beckett-based compositions of different genres and styles and from various countries responding to virtually the entire Beckettian œuvre, Beckett's poems, plays and prose have exerted an influence on composers unequalled by those of any other 20th-century author. This study shows that Beckett's double-coded language, sounds and images have served as a blueprint for crossing medial and social gaps in favor of a de-hierarchization of both the author-audience relationship and the intermedial interplay. As a result of this paradigm shift toward more participatory artistic modes and toward a postmodern "radical pluralization" (Wolfgang Welsch) of meaning and expressive vehicles, Beckett regarded music as an equal interlocutor of language and, vice versa, composers have become more receptive to entirely new modes of text-setting. "Nec tecum nec sine te," a Latin phrase by Ovid cited by Beckett to describe the double-edged relationship between Hamm and Clov from Endgame – interdependent yet noncommittal – equally applies to the text-music interplays portrayed in the present work

    L'axe RAS/PI3K renforce la sénescence cellulaire par la déstabilisation de ZNF768

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    RAS est une petite protéine Rho-GTPase à la tête d'un réseau de signalisation prolifératif important. Les sentiers activés par RAS incluent les Mitogen-Activated proteins Kinases (MAPK) et la voie Phosphoinositide-3-kinase (PI3K) /Mechanistic Target of Rapamycin (mTOR). Bien que de nombreuses évidences soutiennent une forte implication de RAS dans la carcinogenèse, les mécanismes moléculaires précis liant RAS et prolifération cellulaire ne sont pas tous élucidés. En utilisant des données publiques de phosphoprotéomique, notre équipe a identifié Zinc Finger Protein 768 (ZNF768) comme une nouvelle cible de RAS essentielle à la croissance et à la prolifération. ZNF768 est un facteur de transcription qui est déstabilisé au niveau post-traductionnel par les voies MAPK et mTOR/AKT. La déplétion aigue de ZNF768 induit prématurément une entrée en sénescence, un état caractérisé par un arrêt irréversible du cycle cellulaire, et souvent mis en place en réponse au stress. Nos études montrent que ZNF768 est dégradée durant ce phénomène ainsi que durant la sénescence réplicative. De plus, la surexpression de ZNF768 réduit l'entrée en sénescence, via un mécanisme majoritairement dépendant du facteur de transcription p53, qui joue un rôle important dans la sénescence. ZNF768 affecte négativement la phosphorylation de certains résidus clés pour l'activation de p53 et inhibe son activité transcriptionnelle. Nous avons par ailleurs démontré une interaction physique entre ces deux protéines. L'ensemble de ces résultats suggère que les voies MAPK et mTOR, toutes deux activées par RAS, déstabilisent ZNF768 afin de renforcer la sénescence prématurée. De manière intéressante, les niveaux de ZNF768 sont élevés dans certaines tumeurs humaines. Ainsi, nous proposons un modèle dans lequel ZNF768 puisse favoriser la carcinogenèse en réduisant la sénescence et en favorisant la prolifération.RAS is a small Rho-GTPase protein that integrates growth factors signaling and activates several proliferating pathways including Mitogen-Activated Proteins Kinases (MAPK) and Phosphoinositide-3-kinase (PI3K)/Mechanistic Target of Rapamycin (mTOR). Although many evidence indicate that RAS is involve in carcinogenesis, the molecular mechanisms that link RAS to cellular proliferation are not well understood. By using phosphoproteomics data, our team identified Zinc Finger Protein 768 (ZNF768) as a new target of RAS signaling essential to growth and proliferation. ZNF768 is a transcription factor destabilized at the post-translational level by MAPK and mTOR/AKT. The acute depletion of ZNF768 induces senescence, a stable arrest of the cell cycle triggered by cellular stress. Our results show that ZNF768 is depleted during replicative and premature senescence. In addition, overexpression of ZNF768 bypasses senescence by a mechanism that is mainly dependent on the activity of p53, a transcription factor involved in senescence. Interestingly, ZNF768 interacts with p53 and inhibits its transcriptional activity by modulating its phosphorylation. Thus, MAPK and mTOR/AKT pathways destabilise ZNF768 to reinforce senescence. Moreover, ZNF768 levels are high in various human tumors. Altogether, these results suggest that ZNF768 promotes carcinogenesis by blocking senescence and by stimulating proliferation

    A Triple-Faced Janus: Tom Jones as Bastard, Pretender, and Cowan

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    The main aim of this research is to carry out a three-level analysis of The History of Tom Jones; a Foundling (1749) by Henry Fielding, following and explaining its peculiar layering of various narrative lines. Firstly, the plot is largely centred on both the theme of Tom\u2019s legitimacy as heir to Allworthy\u2019s estate and his much needed prudence to enter into possession of it, by means of his final marriage. Secondly, these issues widely reflect the historical background in which the novel took shape, that is, the rebellion of 1745. Indeed, Tom\u2019s image is based on Charles Edward Stuart, the so-called Young Pretender; his wife-to-be Sophia is mistaken for Jenny Cameron, the Pretender\u2019s Scottish lover; Tom\u2019s travels have much in common with the wanderings of the notorious claimant to the British throne. Thirdly, a symbolic level encompasses the preceding ones: contemporary rumours had it that Charles Edward Stuart was the universal leader of Freemasonry, probably the \u201chidden Grand-Master\u201d (Marsha Keith Schuchard). From this perspective, Tom\u2019s wanderings after being turned out from Paradise Hall, his adventures in the 'country section' under the falling rain, his imprisonment in London and gradual inner rebirth leading to his marriage to Sophia Western, describe a sort of ritual initiation following a typically masonic punishment for cowans, this latter being the name for a mason who has not been regularly bred, an intruder overhearing the secrets of a lodge, and therefore \u201cplaced under the eaves of the house in rainy weather, till the water runs in at his shoulders and out at his heels\u201d (Albert Mackey). Therefore, my aim is to underscore the aspects which link the bastard, the individual improperly introduced into a household, to the figure of the pretender, the improper claimant to the throne, and to the cowan, the irregularly trained mason. Only following this line of thought, Tom\u2019s progress can eventually be interpreted as a successful attempt to restore order amid various forms of illegitimacy. Moreover, such state of things portrays a rather different mid-eighteenth-century Britain, where the Stuarts regain their power and the Hanoverian monarchy is called into question

    The Key 1994

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    Bowling Green State University 1994 Key Yearbookhttps://scholarworks.bgsu.edu/yearbooks/1154/thumbnail.jp
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