The gravitational path integral in eary universe cosmology

Die Pfadintegral-Quantisierung der semi-klassischen Gravitation ist einer der vielversprechendsten Ansätze zur Vereinheitlichung von Quantenmechanik und allgemeiner Relativitätstheorie. In dieser Arbeit untersuchen wir die Konsequenzen der Anwendung dieses Pfadintegralansatzes auf die Kosmologie des sehr frühen Universums. Im ersten Teil konzentrieren wir uns auf den no-boundary proposal, der einen nicht-singulären Anfang des Universums konstruiert, indem er sich auf das gravitative Pfadintegral der allgemeinen Relativitätstheorie stützt. Wir beweisen, dass die no-boundary Lösung das Hinzufügen von Korrekturen höherer Ordnung zur Gravitationswirkung überlebt. Unsere Analyse deutet also darauf hin, dass semi-klassische Ergebnisse auch in der perturbative Störungstheorie der vollständigen Quantengravitation gültig sind. Anschließend beziehen wir ein Skalarfeld in den neuen no-boundary proposal ein, der im Lorentz-Formalismus als Summe über Geometrien mit festem Anfangsimpuls definiert ist. Unsere Ergebnisse sind der Schlüssel zur Bestätigung der Gültigkeit des neuen no-boundary proposals, denn Skalarfelder sind das einfachste Beispiel für Materiefelder, die in einer realistischen Theorie des frühen Universums enthalten sein müssen. Der zweite Teil der Arbeit befasst sich mit der Pfadintegralansatz für allgemeineren Modellen des frühen Universums. Zunächst testen wir die Gültigkeit des semi-klassischen Limits dieser Modelle mit dem Kriterium der endlichen Amplitude, das z.B. Theorien höherer Ordnung der Gravitation stark einschränkt und den no-boundary proposal sowie emergente Universen begünstigt. Schließlich wenden wir das Kriterium der komplexen Metrik von Kontsevich und Segal auf kosmologische Hintergründe an. Im Kontext der Quantenkosmologie angewandt, führt es zu einem neuen Verständnis des gravitativen Pfadintegrals im no-boundary proposal und schließt generische quantum bounces aus.The path integral quantization of gravity is one of the most promising approaches to unify quantum mechanics and general relativity. This thesis pursues the consequences of the path integral approach applied to the cosmology of the very early universe, for which this unification is crucial. The first part focuses on the no-boundary proposal, which constructs a non-singular beginning of the universe by relying on the gravitational path integral of general relativity. We prove that the no-boundary solution survives the addition of higher-order corrections to the gravity action, usually found in high-energy completions of general relativity such as string theory. This indicates that semi-classical results may still hold at the perturbative level of full quantum gravity. We then include a scalar field in the new no-boundary proposal, defined in the Lorentzian formalism as a sum over geometries with fixed initial momentum flow. Our results are key to confirming the viability of the proposal, but also highlight the non-locality puzzle of the no-boundary proposal in the presence of matter fields, for which we offer new perspectives. The second part of the thesis deals with the path integral treatment of more general early universe models. First we test the validity of the semi-classical limit of these models with a finite amplitude criterion, which severely constrains e.g. higher-order theories of gravity and globally favors the no-boundary proposal and emergent-like universes. At last, we apply Kontsevich and Segal’s complex metric criterion to cosmological backgrounds. This criterion tests the path integral convergence of any quantum field theory on a given metric background. Applied in the context of quantum cosmology, it leads to a new understanding of the path integral in the no-boundary proposal, rules out generic quantum bounces, and stresses the limitation of minisuperspace for classical transitions in de Sitter spacetime

Desempenho motor de lactentes filhos de mães adolescentes : estudo comparativo

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Medicina, Programa de Pós-Graduação em Ciências Médicas, 2013.Introdução: Um dos maiores problemas referentes à adolescência, no âmbito da saúde pública em alguns países, incluindo o Brasil, são as altas taxas de gestação nessa fase da vida. Ao longo das últimas décadas, várias pesquisas têm documentado os riscos de uma gravidez na adolescência tanto para a mulher como para os seus filhos, das quais podemos destacar os estudos relacionados aos resultados gestacionais, perinatais, os cuidados que essas mães destinam aos seus filhos bem como o desenvolvimento neuropsicomotor de crianças filhas de mães adolescentes. Objetivo: O objetivo principal deste estudo foi avaliar o desenvolvimento motor grosso de lactentes filhos de mães adolescentes comparando-o ao de lactentes filhos de mães adultas. Métodos: Realizou-se um estudo transversal, do qual participaram 59 crianças, selecionadas em dois serviços públicos de assistência à saúde localizados na região administrativa de Ceilandia-DF. Aplicou-se o instrumento Alberta Infant Motor Scale (AIMS) para avaliar o desenvolvimento motor grosso e foram coletados dados socioeconômicos e biológicos das mães. Utilizou-se o teste exato de Fisher para as variáveis categóricas e o teste não paramétrico de soma de postos de Wilcoxon para as variáveis continuas, considerando diferença estatisticamente significativa quando p< 0.05. Resultados: sugerem um desempenho motor inferior em filhos de mães adolescentes (p= 0.0336) quando comparados aos filhos de mães adultas. As mães adolescentes também apresentaram diferença estatisticamente significativa em relação ao estado civil (p=0.014), assim como anos de escolaridade (p= 0.047). Outras características como número de consultas de pré- natal, tipo de parto, renda familiar e apoio familiar não mostraram diferenças significativas entre os grupos. Conclusão: a idade materna pode ser um fator de risco para atraso do desenvolvimento motor do bebê.Introduction: One of the biggest problems concerning adolescence, within public health care systems of some countries, including Brazil, is high gestation rates during this stage of the life cycle. Over past decades many studies have documented the risks of teenage pregnancies for both women and their children, of which we can detach studies related to gestational e perinatal results, to the assistance those mothers have to their children, as well as to neuropsychomotor development of adolescent mothers' infant children. The main objective of this study is to assess the motor development of infant children of adolescent mothers when compared to infant children of adult mothers. Methods: A Cross-sectional survey was carried out with 59 children selected by simple random sampling in two public health care assistance institutions located in the administrative region of Ceilândia-DF. Alberta Infant Motor Scale instrument was applied to assess the gross motor development. Biological and socio-economic data collection was also used for mother's epidemiological profile analysis. The Fisher Exact test was utilized to compare categorical variables and the non-parametric Wilcoxon Rank-Sum test to continuous variables, considering p<0.05. The results indicate lower motor performance of children of adolescent mothers (p= 0.0336) when compared to children of adult mothers. Adolescent mothers also present significant statistical difference in their marital status (p=0.014) as well as in their schooling (p= 0.047). Other results, such as prenatal consultations, types of delivery and family support proved to be homogeneous. It is concluded that maternal age can be a risk factor for motor development abnormalities

No-boundary solutions are robust to quantum gravity corrections

The no-boundary proposal is a theory of the initial conditions of the universe formulated in semi-classical gravity, and relying on the existence of regular (complex) solutions of the equations of motion. We show by explicit computation that regular no-boundary solutions are modified, but not destroyed, upon inclusion of expected quantum gravity corrections that involve higher powers of the Riemann tensor as well as covariant derivatives thereof. We illustrate our results with examples drawn from string theory. Our findings provide a crucial self-consistency test of the no-boundary framework.Comment: 39 pages, no figure, v2: matches the published versio

CUIDADOS E PREVENÇÕES AO DIABETES NO BRASIL

Diabetes, as well as other chronic diseases such as hypertension, occupy a place of relevance with regard to the diseases that more affect the population and more cause deaths. Public policies aimed at its eradication, although advantageous, are insufficient and costly. Thus, there is the alternative of early diagnosis of the disease, screening, which obtained, of the total, 44% representing new cases. The objective is the solution through new policies and knowledge of the disease. The degrading factor of the disease requires its study, when observed in close relatives. The surveys used closed questionnaires to obtain data. The conclusion is that the research proposals are efficient as complementary to existing policies.O diabetes, assim como outras doenças crônicas tais como hipertensão, ocupa um lugar de relevância no que diz respeito às doenças que mais atingem a população e mais causam mortes. As políticas públicas voltadas à sua erradicação, embora vantajosas, são insuficientes e custosas. Sendo assim, há a alternativa do diagnóstico precoce da doença, rastreamento, que obteve, do total, 44% representando novos casos. Objetiva-se a solução por meio de novas políticas e conhecimento da doença. O fator degradante da doença exige seu estudo, ao ser observada em familiares próximos. As pesquisas utilizadas usaram questionários fechados para obter dados. A conclusão é que as propostas das pesquisas se mostram eficientes como complementos às políticas existentes

Воспитание иностранных студентов в ходе учебного процесса.

ИНОСТРАННЫЕ СТУДЕНТЫВОСПИТАТЕЛЬНАЯ РАБОТ

The Role of Food Tourism in Supporting Vibrant Identities and Building Education among Diverse Communities and Visitors

Toronto, located in the province of Ontario, is the largest city in Canada and has been named one of the most diverse cities in the world. The Greater Toronto Areas (GTA)’s ethnic diversity is synonymous with culinary diversity and an increasing demand for world foods. The GTA has been home to Indigenous peoples for thousands of years and three hundred years of immigration to Ontario from all corners of the globe have created an environment of exchange that continuously alters the food and drink available in the region. Toronto continues to maintain its multicultural character while growing at a pace of around 100,000 new residents per year (Galloway, 2017). As of 2017, nearly 50% of the city’s population had a newcomer background. It is estimated that by 2031, 75% of the GTA’s population will be either immigrants or Canadian-born children of immigrants (Nakamura and Donnelly, 2017). The region’s multicultural makeup drives disruption and innovation of food systems through a vibrant and ever-evolving food scene. The diversity of this food scene is difficult to define and package into a single tourism offering. Taking the context of growing diversity in the GTA as the starting point, the primary question explored in this paper is: What role can food tourism play in supporting vibrant identities while providing learning opportunities around local food systems and cultural heritage? This question is explored through a discussion of foods produced in the rural areas around the GTA and the foods sought by diverse communities in urban centres of the GTA. Through analysis and comparison of land management and agricultural policy documents, community engagement initiatives, and current food tourism programs, this paper also considers the impact that the GTA’s cultural diversity has in shaping the future of food education and food tourism

BICEPS: An improved characterization model for low- and intermediate-mass exoplanets

Context. The number of exoplanets with precise mass and radius measurements is constantly increasing thanks to novel ground- and space-based facilities such as HARPS, ESPRESSO, CHEOPS, and TESS. The accuracy and robustness of the planetary characterization largely depends on the quality of the data, but also requires a planetary structure model, capable of accurately modeling the interior and atmospheres of exoplanets over a large range of boundary conditions. Aims. Our goal is to provide an improved characterization model for planets with masses between 0.5 and 30 Earth masses, equilibrium temperatures below <2000 K, and a wide range of planetary compositions and physical phases. Methods. In this work, we present the Bayesian Interior Characterization of ExoPlanetS (BICEPS) model, which combines an adaptive Markov chain Monte Carlo sampling method with a state-of-the-art planetary structure model. BICEPS incorporates many recently developed equations of state suited for large ranges of pressures and temperatures, a description for solid and molten planetary cores and mantles, a gaseous envelope composed of hydrogen, helium, and water (with compositional gradients), and a non-gray atmospheric model. Results. We find that the usage of updated equations of state has a significant impact on the interior structure prediction. The impact varies, depending on the planetary composition. For dense rocky planets, BICEPS predicts radii a few percent different to prior internal structure models. For volatile rich planets, we find differences of 10% or even larger. When applying BICEPS to a particular exoplanet, TOI-130 b, we inferred a 25% larger water mass fraction and a 15% smaller core than previous models. Conclusions. The presented exoplanet characterization model is a robust method applicable over a large range of planetary masses, compositions, and thermal boundary conditions. We show the importance of implementing state-of-the-art equations of state for the encountered thermodynamic conditions of exoplanets. Hence, using BICEPS improves the predictive strength of the characterization process compared to previous methods.ISSN:0004-6361ISSN:1432-074