A lengthy, and at times heated, debate on the regulation of animal numbers has proceeded in the literature for over half a century. A wide variety of causal agents - from sun spots to a shortage of trace elements - has been proposed to explain the observed densities, and a wide variety of mechanisms has also been proposed - from natural selection to chance. Only occasionally have any of these proposals been rigorously tested, and the survival of partially or totally conflicting hypotheses has been correspondingly high. I have attempted to test just one of these proposals: the polymorphism hypothesis of Chitty (Proc. Ecol. Soc. Australia 2:51-78, 1967.) According to this hypothesis, any natural population which lives in a highly favourable habitat can regulate its numbers through the action of two morphs, one characterized by a high fecundity and the other by a superior ability to hold its position in the environment. Population density is postulated to be a function of the relative frequency of the morphs and to change in a predictable way. I have conducted five experiments to investigate the existence of, and the mode of interaction between, these presumed morphs in Tribolium confusum, the questions asked being: 1) Is the density achieved by open populations (i.e. those from which emigration is allowed) different from that in closed populations (i.e. those from which emigration is prevented)? 2) Is the mechanism of regulation in open populations different from that in closed populations? 3) Is the tendency to migrate a constant property of individuals? 4) Is the density achieved by populations founded by migrants different from that of populations founded by non-migrants? 5) Is the density achieved by open populations (with migration by self-selection) different from that achieved by closed populations from which an equal number of animals are removed at random? I found the answers to all these questions to be 'yes', and the differences in each case to be in the direction predicted by the polymorphism hypothesis. I suggest that the polymorphism hypothesis is useful for predicting future densities of populations from which emigration is occurring, but is not useful for predicting densities in populations 1) from which animals cannot escape or 2) in which mortality caused by extrinsic factors is so great that, despite high fecundity, the populations are unable to produce a migrating surplus. I argue that 1) and 2) are rare in nature, or at least have been studied rather seldom. / Science, Faculty of / Zoology, Department of / Graduate

Thesis (Ph. D.)--University of Wisconsin--Madison, 1947. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 54-68).

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Internet application servers are currently designed to maximize resource efficiency by servicing many thousands of users that may fall within disparate privilege classes. Pooling users into a shared execution context in this way enables adversaries not only to laterally propagate attacks against other clients, but also to use the application server as a "confused deputy" to gain escalated privileges against sensitive backend data. In this work, we present the Single-use Server (SuS) model, which detects and defeats these attacks by separating users into isolated, containerized application servers with tailored backend permissions. In this model, exploited servers no longer have unfettered access to the backend data or other users. We create a prototype implementation of the SuS model for the WordPress content management system and demonstrate our model's ability to neutralize real-world exploits against vulnerable WordPress versions. We find that the SuS model achieves a high level of security while minimizing the amount of code modification required for porting an application server. In our performance evaluation, we find that the CPU and latency overheads of the SuS model are very low, and memory consumption scales linearly. We generalize the SuS model to be applicable to a wide range of application server and backend resource pairs. With our modularized codebase, we port IMAP, a widely-used mail retrieval protocol, to the SuS model and find that doing so requires minimal effort.

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Submitted by JOSIANE SANTOS DE OLIVEIRA (josianeso) on 2018-08-02T16:54:04Z No. of bitstreams: 1 Flóra Simon da Silva_.pdf: 3922908 bytes, checksum: 8c0355bab398eaf3766d305f5f5bb693 (MD5) / Made available in DSpace on 2018-08-02T16:54:04Z (GMT). No. of bitstreams: 1 Flóra Simon da Silva_.pdf: 3922908 bytes, checksum: 8c0355bab398eaf3766d305f5f5bb693 (MD5) Previous issue date: 2018-03-28 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / PROEX - Programa de Excelência Acadêmica / Esta dissertação aborda conceitos da midiatização em relação ao cinema e as apropriações de seus elementos nos meios digitais pelos atores sociais. Para tanto, nos propomos a analisar a circulação do gif Confused Travolta, verificando as transformações que ocorrem no circuito que se forma entre sua produção e seu reconhecimento. Tem como objetivo principal compreender como as apropriações de elementos cinematográficos, a lógica do cinema e o personagem Vincent Vega produzem sentidos, criam circuitos complexos de comunicação, transformam as interações sociais e potencializam novos dispositivos de comunicação. Nesse sentido, a questão que levantamos e que norteia a pesquisa é O que transforma, no circuito da midiatização, quando imagens são construídas a partir de elementos cinematográficos e se deslocam para sistemas de lógicas diferentes do seu original? com base uma base teórica, problematizamos perspectivas da sociedade dos meios para a sociedade em vias de midiatização. Além disso, ao levantar os aspectos essenciais sobre conceitos da circulação e circuitos, desenvolvemos questões a partir das apropriações e usos nos meios digitais. Este levantamento teórico articulou, juntamente com algumas teorias do cinema, a possibilidade de reflexão sobre a estrutura cinematográfica entre a montagem e a justaposição de cenas, lógicas de produção e personagens arquetípicos e como são observadas estas lógicas no gif Confused Travolta. Através da análise, foi possível verificar os atravessamentos da midiatização nas práticas sociais e, em consequência, nas apropriações dos elementos cinematográficos. Consideramos que o gif em questão, atravessado pela lógica da midiatização, em que os atores sociais produzem materiais para pôr em circulação, aproxima-se e distancia-se da sua referência original, transforma interações entre atores sociais, produz o agenciamento de fluxos e conversações nos meios digitais, ressignifica o sentido do personagem Vincent Vega e propõe a formação de um novo dispositivo tentativo de comunicação através do gif Confused Travolta. / This dissertation approaches concepts of mediatization in relation to cinema and the appropriations of its elements in digital media by social actors. For this, we propose to analyze the circulation of the Confused Travolta gif, verifying the transformations that occur in the circuit that is formed between its production and recognition. Aims to understand how the appropriations of cinematographic elements such as the cinema logic and the Vincent Vega character produce meaning, create complex circuits of communication, transform social interactions and potentiate new communication devices. In this sense, the question that is raised and that guides research is what transforms, in the circuit of mediatization, when images are constructed from cinematographic elements and are moved to systems of logics different from their original? From a theoretical base, we problematize perspectives of the society of the means for the society in the process of mediatization. Besides that by raising the essential aspects of concepts of circulation and circuits, we develop questions from appropriations and uses in digital media.This theoretical survey articulated, along with some theories of cinema, the possibility of reflection on the cinematographic structure between the assembly and juxtaposition of scenes, production logics and archetypal characters and how these logics are observed in the Confused Travolta gif. Through the analysis it was possible to verify the crossings of mediatization in social practices and, consequently, in the appropriations of the cinematographic elements.We consider that the gif in question, crossed by the logic of mediatization, where social actors produce materials to put into circulation, approaches and distances itself from its original reference, transforms interactions between social actors, produces the agency of flows and conversations in the digital media, resigns the sense of the character Vincent Vega and proposes the formation of a new tentative device of communication through the Confused Travolta gif.

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