No contexto de Renormalização Wilsoniana, os fluxos do grupo de renormalização (RG flows) são um conjunto de equações diferenciais que define como as constantes de acoplamento de uma teoria dependem de uma escala de energia. o conteúdo destes é semelhante a como sistemas termodinâmicos estão relacionados com a temperatura. Neste sentindo, é natural olhar para estruturas nos fluxos que demonstram um comportamento termodinâmico. A teoria matemática para estudar estas equações é chamada de sistemas dinâmicos e aplicações desta têm sido usadas no estudo de RG flows. Como exemplo o teorema-C de Zamolodchikov e os equivalentes teoremas em dimensões maiores mostram que existe uma função monotonicamente decrescente ao longo do fluxo e é uma propriedade que se assemelha à segunda lei da termodinâmica, estão relacionadas com a função de Lyapunov no contexto de sistemas dinâmicos e podem ser usadas para excluir a possibilidade de comportamentos assintóticos exóticos, como fluxos periódicos ou ciclos limites. Estudamos a teoria de bifurcação e a teoria de índice, que foram propostas como sendo úteis no estudo de RG flows: a primeira pode ser usada para explicar constantes cruzando pela marginalidade e a segunda para extrair informação global do espaço em que os fluxos vivem. Nesta dissertação, também olhamos para aplicações em RG flows holográficos e tentamos buscar relações entre as estruturas em teorias holográficas e as suas duais teorias de campos. / In the context of Wilsonian Renormalization, renormalization group (RG) flows are a set of differential equations that defines how the coupling constants of a theory depend on an energy scale. These equations closely resemble thermodynamical equations and how thermodynamical systems are related to temperature. In this sense, it is natural to look for structures in the flows that show a thermodynamics-like behaviour. The mathematical theory to study these equations is called Dynamical Systems, and applications of that have been used to study RG flows. For example, the classical Zamolodchikov\'s C-Theorem and its higher-dimensional counterparts, that show that there is a monotonically decreasing function along the flow and it is a property that resembles the second-law of thermodynamics, is related to the Lyapunov function in the context of Dynamical Systems. It can be used to rule out exotic asymptotic behaviours like periodic flows (also known as limit cycles). We also study bifurcation theory and index theories, which have been proposed to be useful in the study of RG flows, the former can be used to explain couplings crossing through marginality and the latter to extract global information about the space the flows lives in. In this dissertation, we also look for applications in holographic RG flows and we try to see if the structural behaviours in holographic theories are the same as the ones in the dual field theory side.

The focus is on cross-sectional dependence in panel trade flow models. We propose alternative specifications for modeling time invariant factors such as socio-cultural indicator variables, e.g., common language and currency. These are typically treated as a source of heterogeneity eliminated using fixed effects transformations, but we find evidence of cross-sectional dependence after eliminating country-specific and time-specific effects. These findings suggest use of alternative simultaneous dependence model specifications that accommodate cross-sectional dependence, which we set forth along with Bayesian estimation methods. Ignoring cross-sectional dependence implies biased estimates from panel trade flow models that rely on fixed effects. / Series: Working Papers in Regional Science

Venture capital (VC), a historically American industry, has been in the process of globalizing in recent years. International venture capital flows (investing outside of one’s own country) have grown substantially over the past 30 years and even more dramatically in just the past decade. Previous research has mostly highlighted the determinants of where capital flows. However, research on the factors in a VC’s home country that affect investments abroad has been underdeveloped. To address this gap, this paper explores the impact of home country economic conditions on VCs’ propensity to invest abroad. I find that higher interest rates and economic wellbeing in a country (as measured by GDP growth and stock market capitalization to GDP) are associated with less deal flow abroad and, that higher foreign exchange rates are related to greater deal flow. I also note an interesting divergence in the role of these factors between VCs located in countries that exhibit different levels of international investing experience. My research indicates that VCs’ home country economic conditions do play a role in their decisions to invest abroad and suggests that these considerations may be different depending on the experience level of the VC industry in the firm’s country.

This work deals with the design of a hybrid time integrator that couples spatially explicit and implicit time integrators. In order to cope with the industrial solver of Ariane Group called FLUSEPA, the explicit scheme of Heun and the implicit scheme of Crank-Nicolson are hybridized using the transition parameter : the whole technique is called AION time integration. The latter is studied into details with special focus on spectral behaviour and on its ability to keep the accuracy. It is shown that the hybrid technique has interesting dissipation and dispersion properties while maintaining precision and avoiding spurious waves. Moreover, this hybrid approach is validated on several academic test cases for both convective and diffusive fluxes. And as expected the method is more interesting in term of computational time than standard time integrators. For the extension of this hybrid approach to the temporal adaptive method implemented in FLUSEPA, it was necessary to improve some treatments in order to maintain conservation and acceptable spectral properties. Finally the hybrid time integration was also applied to a RANS/LES turbulent test case with interesting computational time while capturing the flow physics.

The ultimate goal of this research is to develop the capability of direct numerical simulation of a flow containing numerous rigid finite size particles. In order to reach this goal, we have implemented the smoothed profile method (SPM) in the University of Iowa in-house solver, pELAFINT3D and overcame several challenges related to the method. This includes a proposed formulation for the interface thickness and many validations and comparisons with experimental data as well as with a second-order accurate sharp interface method. As one of the issues related to low-density particles is the instability, SPM has been improved by developing to a fully implicit scheme. Moreover, use of higher order integration formulation and implementation of Euler parameters have been shown to be helpful in stabilization of the calculations. To preserve the efficiency when the number of the particles increases, local mesh refinement is shown to be a very effective tool. A revised version of SPM that has only one projection step is proposed to improve the efficiency of the method. A comprehensive efficiency study is performed and it has been shown that the new method is less expensive in problems with high added mass effect when strongly coupled fluid-structure interaction schemes are used. Moreover, the code is massively parallelized using MPI and PETSc libraries. The parallelization includes I/O, operations leading to construction of the linear solver as well as the solver itself. Simulation of a particle laden flow involves particles collisions. Two novel collision models are suggested which are able to avoid particle overlapping for arbitrary shape particles. The methods are efficient as they are not involved with extra grid refinement related to implementing lubrication forces. The issue of handling continuously changing number of particles in a particle laden flow is solved by implementation of a linked list data structure for the particles. By studying a flow over a constricted region we showed that the platelets’ activation is more likely to happen for the particles that pass from the middle of the upper bump region because those particles will have longer exposure time to the high shear flow behind the bump. PDF contour of particles’ presence show the more concentrated presence of the particles near the bump. Moreover, the interaction of RBCs and platelets pushes the platelets toward the wall after the bottom wall.

La mise en place de la politique monétaire non conventionnelle en 2008 aux États-Unis a coïncidé avec d'importants mouvements de capitaux et de taux de change dans les pays émergents. Ces derniers ont accusé la banque centrale américaine d'adopter une politique « d'appauvrissement du voisin » et de créer ces effets de report. En 2013, à la suite de l'annonce du ralentissement graduel du rythme de cette politique monétaire, certains pays émergents ont subi d'importantes crises financières. Dans ce contexte, cette thèse se propose d'étudier dans quelle mesure la politique monétaire non conventionnelle de la Réserve fédérale américaine a induit des effets de report en termes de mouvements de capitaux et de taux de change. Alors que la normalisation de cette politique monétaire est entamée, il est primordial de comprendre les implications internationales des décisions de la Réserve fédérale pour pouvoir contenir les risques potentiels. Tout d'abord, nous étudions les mécanismes et leurs effets sur les pays émergents dans le cadre d'une revue de la littérature. Nous montrons que la politique monétaire de la Réserve fédérale a bien été responsable d'effets de report. Ensuite, nous révélons, de façon empirique, que les conséquences présentent une certaine hétérogénéité dans le temps, en fonction des modalités d'intervention de la banque centrale américaine, ainsi que selon les pays. Nous établissons qu'il n'y a pas de réelle symétrie entre la phase expansionniste et celle de normalisation. De ce fait, la normalisation n'apparaît pas entrainer des reflux de capitaux dans les pays émergents. Finalement, nous nous intéressons aux moyens dont disposent les pays émergents pour limiter les effets de report. Nous montrons que les contrôles de capitaux et les politiques macroprudentielles peuvent permettre de réduire les mouvements de capitaux. Plus précisément, l'efficacité des contrôles de capitaux est conditionnée par leur accumulation. Plus le pays en est doté, plus il limite les effets de report. L'efficacité de la politique macroprudentielle dépend quant à elle de la qualité des institutions dans le pays émergent et de l'intensité de la politique monétaire américaine. / The implementation of the U.S. unconventional monetary policy in 2008 coincided with massive capital inflows and exchange rate appreciation for emerging markets. They implicate the Federal Reserve to pursue a « Beggar-thy-neighbor » policy and to create spillovers. In 2013, following the announcement of the « Tapering », some emerging markets suffered from significant financial crises. In this context, this thesis intends to study how the U.S. unconventional monetary policy led to capital flows and exchange rate movements spillovers. As the normalization of this monetary policy is initiated, understanding the international implications of the Federal Reserve's decisions is essential to contain potential risks. For this purpose, we firstly study mechanisms and their impacts on emerging countries by a literature review. We show that the Fed monetary policy caused capital flows and exchange rate spillovers in the last decade. Then, we reveal empirically that the impacts exhibit heterogeneity over time, depend on implementation modalities of the U.S. central bank as well as on the countries. We establish that there is no real symmetrical impacts between accommodative and normalization periods. As a result, the normalization would not lead to capital outflows in emerging countries. Finally, we examine the means that emerging countries can adopt to limit spillovers. We demonstrate that capital controls and macroprudential policies can be efficient to reduce capital inflows. More precisely, the effectiveness of capital controls is conditioned by their accumulation. The more the country adopts it, the more it limits spillovers. Considering macroprudential policies, the intensity of the U.S. monetary policy and the quality of the emerging countries' institutions are two main determinants of their effectiveness.

Dietary protein quality depends on two key measures: true ileal protein digestibility and the metabolic utilization of absorbed amino acids (AA). The objectives of this study were to determine the influence of two dietary factors (antinutritional factors and peptides) on ileal endogenous protein flows; to validate the intubation technique used in humans for ileal digesta sampling; to determine the postprandial metabolic utilization of dietary AA depending on their delivery form and to assess the validity of the growing pig for predicting true ileal protein digestibility in the adult human. Investigations were undertaken in the growing rat, growing pig and adult human. Ileal digesta were collected from euthanised rats, post valve T-caecum cannulated pigs, and naso-ileal intubated conscious adult humans. Ileal endogenous nitrogen (N) and AA were measured using a protein-free (PF) diet, diets containing 15N-labelled casein in the intact (C) or hydrolysed (HC) form, or a diet based on free AA (diet A), for which some dispensable AA were omitted to allow a direct determination of their endogenous flows. Digesta centrifugation and ultrafiltration (diet HC) allowed for the determination of ileal endogenous protein flows and the extent of tracer (15N) recycling. Antinutritional factors from a crude extract of kidney beans (Phaseolus vulgaris), when given at amounts commonly ingested in practice, enhanced ileal endogenous protein flows (rats, PF diet). After adaptation to the diet, body N balance per se did not influence ileal endogenous protein flows (rats, diets PF and A) but dietary peptides led to greater ileal endogenous AA and N flows compared with a protein-free diet. Dietary peptides (HC), compared with peptides naturally released in the gut during protein digestion (C), did not enhance ileal endogenous protein flows (rats, pigs, and humans). The extent of tracer recycling, however, was maximal in frequently-fed rats, lower in meal-fed pigs and minimal in meal-fed humans (65, 21, and 11% of 15N-labelled ileal endogenous proteins, respectively). Naso-ileal intubation for ileal digesta sampling in humans was shown to be an accurate method and evidence was obtained supporting the growing pig as a valid model for predicting true ileal protein digestibility in the adult human. Finally, the form of delivery of dietary AA (from HC or C) influenced the postprandial metabolic fate of dietary AA, especially in terms of AA catabolism kinetics. However, the overall nutritional value of C and HC were similar.

This thesis demonstrates how the geometric connection between the integrable Heisenberg spin equation, the nonlinear Schr??dinger equation and fluid flows with constant velocity magnitude along individual streamlines may be exploited. Specifically, we are able to construct explicitly the complete class of constant speed flows where the constant pressure surfaces constitute surfaces of revolution. This class is undoubtedly important as it contains many of the specific cases discussed earlier by other authors.

The thesis concentrates on measuring the benefits and losses of implementing regional trade agreements. In particular, the thesis analyses trade flow changes, foreign direct investment inflow changes, industrial total factor productivity changes and specific commodity trade flow changes in Australia and China. Four empirical studies are undertaken. Firstly, the thesis introduces the gravity model to estimate the effect of regional trade agreements on trade flow changes, focusing on thirty-nine countries and areas from seven regional trade agreements during 1980-2004. The results show that there are trade creation and trade diversion effects for various memberships. The results further show that China experiences an export creation effect for its APEC membership while Australia has an import diversion effect for its CER membership. When trade between Australia and China is considered, Australia's CER membership impedes its trade with China. However, both Australia and China benefit from attending APEC jointly to enlarge their bilateral trade. Secondly, a modified gravity model is undertaken to test the impact of regional trade agreements on foreign direct investment inflows to Australia and China. It uses the same regional trade agreements to that of the trade flow study for the period of 1980 to 2004 for Australia and 1985 to 2004 for China. The results show that CER members tend to strengthen their bilateral foreign direct investment cooperation after the implementation of CER trade and investment liberalization. Thirdly, the impact of regional trade agreements is examined on industrial total factor productivity growth. The findings show that industries with comparative trading advantages in both Australia and China tend to improve their total factor productivity upon liberalizing trade both bilaterally and multilaterally. However, industries with comparative disadvantages need more protection against severe foreign competition. It uses data from 1974-75 to 2004-05 for the Australian market sector analysis, from 1968-69 to 1990-2000 for the Australian manufacturing industry analysis, and from 1987 to 2003 for the Chinese industry analysis. Finally, the thesis investigates the impact of regional trade agreements on bilateral commodity trade between Australia and China from 1979 to 2004. A similar gravity model to that of the trade flow study is used, introducing an additional GDP per capita variable to capture the effect of increasing consumers' income on their consumption of particular goods and products type based on product and production characteristics. Both the one-digit and some detailed four-digit commodity classifications described in the Standard International Trade Classification are considered. The results show that participation in regional trade agreements is an important factor that affects Australia's major commodity trade with China. The major contribution of this thesis is the investigation of issues on trade flows and foreign direct investment specifically in Australia and China, together with the studies of the effect of regional trade agreements on industrial total factor productivity improvement and specific commodity trade changes. Due to the increasing pursuit of bilateral and regional economic cooperation in Australia and China, the results of this thesis are of particular importance to both countries in their foreign trade and economic strategies.

Thesis (M.S.) -- Mississippi State University. Department of Mechanical Engineering. / Title from title screen. Includes bibliographical references.