TOPICS IN EARLY UNIVERSE COSMOLOGY

Probes of the cosmic microwave background have revealed a spatially flat and highly isotropic early Universe, seeded with small gaussian primordial perturbations characterized by a nearly scale-invariant power spectrum. The physics responsible for sourcing this early state, however, is still a subject of debate and remains largely speculative. This thesis explores theoretical and computational methods with the aim of further understanding the physical mechanisms which were at play during this early phase of our Universe. An early period of accelerated cosmic expansion, known as inflation, is one possible scenario which has been proposed to account for the above-mentioned large-scale properties of our Universe. It is therefore of interest to place observational constraints on inflationary dynamics in order to better understand its physical origin. To that end, in the first original portion of this work, I employ quantum mechanical inverse-scattering techniques with the aim of shedding light on the stress-energy responsible for this proposed early inflationary state. In particular, I demonstrate a numerical reconstruction of two simulated inflationary histories assuming perfect knowledge of their corresponding observables. Taking stock of these results, I then briefly discuss the application of this technique to more realistic cases incorporating uncertainties and limited access to cosmological data. Subsequently, in the second original portion of this thesis, I investigate the effects of quantum particle production on the cosmic evolution. This effect is particularly relevant for models of the very early Universe, when the energy density generated through this process may back-react on the cosmological expansion. Here I demonstrate a numerical solution to the back-reaction problem in regimes dominated by particle production. Finally, I discuss the relevance of quantum particle production to bounce and inflationary models of the early Universe

Effects of sex, host-plant deprivation and presence of conspecific immatures on the cannibalistic behavior of wild Ascia monuste orseis (Godart) (Lepidoptera, Pieridae)

Effects of sex, host-plant deprivation and presence of conspecific immatures on the cannibalistic behavior of wild Ascia monuste orseis (Godart) (Lepidoptera, Pieridae). The specialist cabbage caterpillar Ascia monuste orseis (Lepidoptera, Pieridae) feeds on plants of the Brassicaceae family, but may eventually ingest conspecific eggs and larvae during the larval stage. The present study examines feeding behavior of 4th and 5th instar cabbage caterpillars in relation to sex, host-plant deprivation and presence of conspecifics. We recorded number of egg ingested per larvae, developmental indices and duration of feeding, exploratory and resting behavior. Kale deprived caterpillars presented high rates of cannibalism, development delay and decreased fecundity. Cannibalism rates were not influenced by the sex of the larvae. In general, the presence of conspecific eggs did not interfere with the frequency and duration of the categorical behavioral events. We conclude that food availability is a strong factor influencing the extent to which A. monuste orseis caterpillars cannibalize.Influência do sexo, da privação de plantas hospedeiras e da presença de imaturos coespecíficos no comportamento canibal de Ascia monuste orseis (Godart) (Lepidoptera, Pieridae) selvagens. A curuquerê-da-couve, A. monuste orseis (Lepidoptera, Pieridae), alimenta-se de plantas da família Brassicaceae, mas ingere ovos e larvas coespecíficos, quando disponíveis, durante a fase larval. O comportamento alimentar de lagartas de 4º e 5º ínstares foi estudado em relação ao sexo e à privação de alimento afetando as taxas de canibalismo, e a presença de ovos coespecíficos afetando o comportamento alimentar. Foram mensurados: número de ovos ingeridos/larva, tempo de desenvolvimento, tamanho do adulto, fecundidade e duração dos comportamentos de alimentação, exploração e repouso. Lagartas privadas de couve apresentaram altas taxas de canibalismo, atraso no desenvolvimento e diminuição do número de oócitos. As taxas de canibalismo não foram influenciadas pelo sexo da larva. De um modo geral, a presença de ovos coespecíficos não interferiu na duração e na freqüência dos comportamentos de repouso, exploratório e alimentar. Concluímos que a disponibilidade de alimento é um fator que influencia fortemente na extensão do canibalismo por lagartas de A. monuste orseis.Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)CNP

UMA REFLEXÃO SOBRE OS ASPECTOS POSITIVOS E NEGATIVOS DA NOVA MODALIDADE DE LICITAÇÃO: PREGÃO ELETRÔNICO

O Pregão Eletrônico, nova modalidade licitatória, foi criado para atender às necessidades da Administração Pública Federal em agilizar a forma de contratar com menos tempo e mais economia para os cofres públicos. A legislação pertinente foi, ao longo dos últimos anos, aperfeiçoando-se, no intuito de melhorar e tornar prioritária esta modalidade perante as já existentes, previstas pela Lei 8.666/93 e suas alterações. Conforme a bibliografia consultada, existem vantagens e desvantagens na aplicação do pregão eletrônico para a Administração Pública Federal. Mas é reconhecida a agilização no processo, uma maior transparência nos atos licitatórios e a economia dos gastos

Características biológicas de Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae) sob estresse de temperatura por gerações sucessivas

The objective of this study was to evaluate the biological characteristics of Trichogramma pretiosum (Riley 1879) under room temperature and temperature stress by successive generations. The evaluation was carried out in split-plot in the time. The temperature (25 ºC – room temperature and 33 ºC – temperature stress) was the Factor 1 and the Generations (n = 15) were the Factor 2. The biological characteristics evaluated were: longevity; posterior tibia length; number of parasitized eggs; emergence; egg-adult period; sexual ratio and deformed individuals. The increase in temperature, from the first generations of T pretiosum, caused an influence in all observed variables. However, for the emergence and sex ratio variables, there was no significant difference between heat stress and control (room temperature) as of the 14th generation, which suggests an adaptability of the species. This adaptability may imply obtaining more aggressive natural enemies in relation to their host (insect pest) and consequently in the greater efficiency of biological control.O objetivo deste estudo foi avaliar as características biológicas de Trichogramma pretiosum (Riley 1879) submetido a temperatura ambiente e estresse térmico por sucessivas gerações. A avaliação foi realizada em parcelas subdividida no tempo. A Temperatura (25 ºC – temperatura Ambiente e 33 ºC – estresse térmico) foi o Fator 1 e as gerações (n = 15) foram o Fator 2. As características biológicas avaliadas foram: longevidade; comprimento da tíbia posterior; número de ovos parasitados; emergência; período ovo-adulto; razão sexual e indivíduos deformados. O aumento da temperatura, provocou, desde as primeiras gerações de T pretiosum, influência em todas as variáveis observadas. Entretanto, para as variáveis emergência e a razão sexual, não houve diferença significativa entre o stress térmico e o controle (temperatura ambiente) a partir da 14 geração , o que sugere-se uma adaptalibidade da espécie. Esssa adaptabilidade podem implicar na obtenção de inimigos naturais mais agressivos em relação ao seu hospedeiro (inseto praga) e consequentemente na maior eficiência do controle biológico.&nbsp

PREVALÊNCIA DE LESÕES NÃO CARIOSAS EM PRATICANTES DE MUSCULAÇÃO

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A Monoallelic Deletion of the TcCRT Gene Increases the Attenuation of a Cultured Trypanosoma cruzi Strain, Protecting Against an in Vivo Virulent Challenge

Trypanosoma cruzi calreticulin (TcCRT) is a virulence factor that binds complement C1, thus inhibiting the activation of the classical complement pathway and generating pro-phagocytic signals that increase parasite infectivity. In a previous work, we characterized a clonal cell line lacking one TcCRT allele (TcCRT+/-) and another overexpressing it (TcCRT+), both derived from the attenuated TCC T. cruzi strain. The TcCRT+/- mutant was highly susceptible to killing by the complement machinery and presented a remarkable reduced propagation and differentiation rate both in vitro and in vivo. In this report, we have extended these studies to assess, in a mouse model of disease, the virulence, immunogenicity and safety of the mutant as an experimental vaccine. Balb/c mice were inoculated with TcCRT+/- parasites and followed-up during a 6-month period. Mutant parasites were not detected by sensitive techniques, even after mice immune suppression. Total anti-T. cruzi IgG levels were undetectable in TcCRT+/- inoculated mice and the genetic alteration was stable after long-term infection and it did not revert back to wild type form. Most importantly, immunization with TcCRT+/- parasites induces a highly protective response after challenge with a virulent T. cruzi strain, as evidenced by lower parasite density, mortality, spleen index and tissue inflammatory response. TcCRT+/- clones are restricted in two important properties conferred by TcCRT and indirectly by C1q: their ability to evade the host immune response and their virulence. Therefore, deletion of one copy of the TcCRT gene in the attenuated TCC strain generated a safe and irreversibly gene-deleted live attenuated parasite with high immunoprotective properties. Our results also contribute to endorse the important role of TcCRT as a T. cruzi virulence factor.Fil: Sánchez Valdéz, Fernando Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Patología Experimental; Argentina. Universidad Nacional de Salta; ArgentinaFil: Perez Brandan, Cecilia Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Patología Experimental; Argentina. Universidad Nacional de Salta; ArgentinaFil: Ramirez, Galia. Universidad de Santiago de Chile; ChileFil: Uncos, Delfor Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Patología Experimental; Argentina. Universidad Nacional de Salta; ArgentinaFil: Zago, María Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Patología Experimental; Argentina. Universidad Nacional de Salta; ArgentinaFil: Cimino, Ruben O.. Universidad Nacional de Salta. Facultad de Cs.naturales. Escuela de Biologia; ArgentinaFil: Cardozo, Ruben M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Patología Experimental; Argentina. Universidad Nacional de Salta; ArgentinaFil: Marco, Jorge Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Patología Experimental; Argentina. Universidad Nacional de Salta; ArgentinaFil: Ferreira, Arturo. Universidad de Santiago de Chile; ChileFil: Basombrio, Miguel Angel Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Patología Experimental; Argentina. Universidad Nacional de Salta; Argentin

A Monoallelic Deletion of the TcCRT Gene Increases the Attenuation of a Cultured Trypanosoma cruzi Strain, Protecting Against an in Vivo Virulent Challenge

Trypanosoma cruzi calreticulin (TcCRT) is a virulence factor that binds complement C1, thus inhibiting the activation of the classical complement pathway and generating pro-phagocytic signals that increase parasite infectivity. In a previous work, we characterized a clonal cell line lacking one TcCRT allele (TcCRT+/-) and another overexpressing it (TcCRT+), both derived from the attenuated TCC T. cruzi strain. The TcCRT+/- mutant was highly susceptible to killing by the complement machinery and presented a remarkable reduced propagation and differentiation rate both in vitro and in vivo. In this report, we have extended these studies to assess, in a mouse model of disease, the virulence, immunogenicity and safety of the mutant as an experimental vaccine. Balb/c mice were inoculated with TcCRT+/- parasites and followed-up during a 6-month period. Mutant parasites were not detected by sensitive techniques, even after mice immune suppression. Total anti-T. cruzi IgG levels were undetectable in TcCRT+/- inoculated mice and the genetic alteration was stable after long-term infection and it did not revert back to wild type form. Most importantly, immunization with TcCRT+/- parasites induces a highly protective response after challenge with a virulent T. cruzi strain, as evidenced by lower parasite density, mortality, spleen index and tissue inflammatory response. TcCRT+/- clones are restricted in two important properties conferred by TcCRT and indirectly by C1q: their ability to evade the host immune response and their virulence. Therefore, deletion of one copy of the TcCRT gene in the attenuated TCC strain generated a safe and irreversibly gene-deleted live attenuated parasite with high immunoprotective properties. Our results also contribute to endorse the important role of TcCRT as a T. cruzi virulence factor.Fil: Sánchez Valdéz, Fernando Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Patología Experimental; Argentina. Universidad Nacional de Salta; ArgentinaFil: Perez Brandan, Cecilia Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Patología Experimental; Argentina. Universidad Nacional de Salta; ArgentinaFil: Ramirez, Galia. Universidad de Santiago de Chile; ChileFil: Uncos, Delfor Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Patología Experimental; Argentina. Universidad Nacional de Salta; ArgentinaFil: Zago, María Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Patología Experimental; Argentina. Universidad Nacional de Salta; ArgentinaFil: Cimino, Ruben O.. Universidad Nacional de Salta. Facultad de Cs.naturales. Escuela de Biologia; ArgentinaFil: Cardozo, Ruben M.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Patología Experimental; Argentina. Universidad Nacional de Salta; ArgentinaFil: Marco, Jorge Diego. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Patología Experimental; Argentina. Universidad Nacional de Salta; ArgentinaFil: Ferreira, Arturo. Universidad de Santiago de Chile; ChileFil: Basombrio, Miguel Angel Manuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Salta. Instituto de Patología Experimental; Argentina. Universidad Nacional de Salta; Argentin