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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
601

Essays in Macroeconomics

Kim, Sung Ryong January 2018 (has links)
This dissertation combines micro-level empirical analyses and general equilibrium models to study the issues of output price, price-cost markup, and business cycle dynamics. In the first chapter, I study how a credit crunch affects output price dynamics. I build a unique micro-level dataset that combines scanner-level prices and quantities with producer information, including the producer's banking relationships, inventory, and cash holdings. I exploit the Lehman Brothers' failure as a quasi-experiment and find that firms facing a negative credit supply shock decrease their output prices approximately 15% relative to their unaffected counterparts. I hypothesize that such firms reduce prices to liquidate inventory and to generate additional cash flow from the product market. I find strong empirical support for this hypothesis: (i) firms facing a negative bank shock temporarily decrease their prices and inventory and increase their market share and cash holdings relative to their counterparts, and (ii) this effect is stronger for firms and sectors with high initial inventory or small initial cash holdings. To discuss the aggregate implications of these findings, I integrate this micro-level study into a business cycle model by explicitly allowing for two identical groups of producers facing different degrees of credit supply shock. The model predicts that a negative credit supply shock leads to a large temporary drop in aggregate inflation---as a result of the aggressive liquidation of inventory---followed by an increase in inflation as producers eventually run out of inventory. This prediction for inflation and inventory dynamics is fully consistent with observations for the 2007-09 recession. In the second chapter, I study price-cost markup cyclicality. Existing empirical evidence on price-cost markup cyclicality is mixed. I find that markups are procyclical unconditionally, and procyclical conditional on demand shock using a flexible production function. The estimated production function features a larger input complementarity than that in a tightly parametrized production function (Cobb-Douglas and CES), producing both greater efficiency and higher markups during an expansion. These results have two striking implications: (i) much of the cyclicality in markups arises from input complementarity, rather than nominal rigidity, and (ii) the U.S. economy behaves as if it has increasing returns to scale. The third chapter studies the business cycle with a Translog production function. We empirically identify a complementarity between labor and energy that leads to procyclical returns to scale, which is not compatible with the tightly parameterized production function commonly used in the literature (Cobb-Douglas and CES). We, therefore, propose a flexible Translog production function that not only features complementarity-induced procyclical returns to scale but is also consistent with a balanced growth path. A simple calibrated business cycle model with the proposed production function generates strikingly data-consistent dynamics following demand shock without relying on either nominal rigidities or countercyclical markups. Our model also produces a stronger amplification effect than the model without complementarity. We then incorporate our production function into a benchmark medium-scale New Keynesian model (Smets and Wouters 2007) and repeat the business cycle accounting exercise. We find that input complementarity leads to a more dramatic decrease in the role of ''suspicious shocks" than of ''structural shocks."
602

In vitro and in vivo analysis of the assembly of the non-collagenous tectorial membrane matrix

Korchagina, Julia Jurievna January 2013 (has links)
Alpha- and beta-tectorin (Tecta and Tectb) are major non-collagenous components of the tectorial membrane (TM). The presence of a zona pellucida (ZP) domain in both tectorins suggests that Tecta and Tectb can form hetero- or homopolymers. It is unclear, however, how these proteins assemble to form the TM matrix. The mechanisms of apical targeting, secretion and processing of the tectorins are also unexplored. I used fluorescently-tagged tectorin constructs for stable transfection into polarised epithelial MDCK cells or transient expression in mouse cochlear cultures to develop an in vitro model of TM matrix assembly. Significant amounts of matrix were not observed with stable tectorin expression in monolayer cultures of MDCK cells. In contrast, I observed substantial amounts of dense extracellular matrix on the apical surfaces of outgrowth zone cells when cochlear cultures were transiently transfected with either Tecta or Tectb. When ectopically expressed in hair cells, Tecta and Tectb locate to the distal tips of the hair bundle. To study the role of the inner-ear protein Ceacam16 in hearing, we generated a Ceacam16 functional null mouse model. The Ceacam16 gene was inactivated by targeted replacement of exons 2-5 with the bacterial lacZ gene. β-gal staining I performed reveals that Ceacam16 is expressed in the epithelial cells of the spiral limbus and inner sulcus, and in both the pillar cells and Deiter's cells. I first detected the presence of Ceacam16 in the TM at P12, four days before the defined striated-sheet matrix is observed. Transmission electron microscopy reveals a complete loss of striated-sheet matrix in Ceacam16 null mice in comparison to the wild-type. The results of this thesis suggest neonatal mouse cochlear cultures as a model for studying tectorin-based extracellular matrix production and also reveal that Ceacam16 is required for normal formation and/or maintenance of striated-sheet matrix.
603

Secagem térmica de lodos de esgoto: determinação da umidade de equilíbrio. / Thermal drying of wastewater sludge: determination of equilibrium moisture.

Airton Checoni David 25 April 2002 (has links)
O estudo apresenta os principais aspectos da operação de secagem térmica de lodos gerados em estações de tratamento de esgotos, os tipos de equipamentos disponíveis no mercado que podem ser utilizados para esse fim e o comportamento da sorção de umidade pelo material seco quando em contato com o ar ambiente. A operação de secagem térmica é uma alternativa para a diminuição do peso e volume de lodos, com conseqüente diminuição dos custos de transporte e disposição final. É considerada, também, um processo de melhoria da qualidade do lodo, pois elimina os microrganismos patogênicos e, ao mesmo tempo, preserva a matéria orgânica presente no lodo, aspectos de importância fundamental quando o lodo/biossólido seco vai ser utilizado na agricultura. Os equipamentos para secagem térmica podem ser diretos ou indiretos. Os principais tipos são: secador rotativo, de soleiras múltiplas, de leito fluidizado, por transporte pneumático e transportadores de esteira. Cada tipo possui vantagens e desvantagens em relação aos demais. A eficiência do processo de secagem térmica é influenciada por uma série de fatores, como: consumo específico de energia, tipo de equipamento utilizado e teores de umidade inicial e final do material. Nos ensaios de laboratório, mediu-se os teores de umidade de equilíbrio do lodo produzido na ETE Baureri, localizada na Região Metropolitana de São Paulo, sob diferentes condições de umidade relativa do ar ambiente. Com esses valores, obteve-se a curva de umidade de equilíbrio do material. Como resultado dessa experiência conclui-se que para cada umidade relativa do ar ambiente há um teor de umidade de equilíbrio do lodo. / The study presents the main aspects of a thermal drying operation of the sludge produced by wastewater treatment plants, the types of equipment likely to be used for this purpose and the sorption behavior of the water contents by the dry material when in contact with the air. The thermal drying operation is an alternative to reduce the weight and volume of the sludge production with a resulting decrease in transportation and final disposal costs. It is also deemed to be a process that improves the sludge quality because includes the elimination of pathogenic microorganisms while preserving the existing organic matter of the sludge, which are aspects of the utmost importance whenever the dry biosolid will be used as fertilizer in agriculture. The thermal drying equipment can be direct or indirect. The main types are: rotary dryers, multi-tray dryers, fluid bed dryers, flash dryers, and conveyor dryers. Each type presents advantages and disadvantages when compared to one another. The efficiency of the thermal drying process is affected by several aspects, such as specific consumption of energy, type of equipment used, and initial and final water contents of the material. The laboratory tests measured the equilibrium moisture contents of the sludge produced by Barueri Wastewater Treatment Plant, located in the São Paulo Metropolitan Region, under different conditions of environment relative humidity. Based on these measurements, an equilibrium moisture curve of the material was obtained. The major conclusion of the experiment was that to each environment relative humidity there is a corresponding equilibrium moisture of the sludge.
604

Essays on financial stability and monetary policy

Paul, Pascal January 2016 (has links)
This thesis consists of three self-contained chapters. Chapter I. The first chapter develops a dynamic general equilibrium model which includes financial intermediation and endogenous financial crises. Consistent with the data, financial crises occur out of prolonged (credit) boom periods and are initiated by a moderate adverse shock. The mechanism which gives rise to boom-bust episodes around financial crises is based on an interaction between the maturity mismatch of the financial sector and an agency problem which results in procyclical lending. I show how to model these features in a tractable way, giving a realistic representation of the financial sector's balance sheet and its lending behavior. The chapter provides empirical evidence on the behavior of the U.S. financial sector's market leverage which is (i) acyclical, (ii) rose mildly prior to the Great Recession, and (iii) increased sharply during the crisis; the model is consistent with these empirical facts. It also predicts and replicates the Great Recession, when confronted with a historical series of structural shocks. Finally, the framework is extended to include price rigidities, nominal debt contracts, and monetary policy. Within this version, I analyze the impact of monetary policy on financial stability and show that a U-shaped pattern of the policy target rate is most likely to increase financial instability. Chapter II. The second chapter models the economy as a time varying vector autoregression, consisting of economic and financial variables. The interest lies in the time varying response of these variables to a monetary policy shock. Monetary policy shocks are identified as the surprise component in policy announcements extracted from price changes in Federal Funds futures around such announcements. These monetary policy surprises enter the model as an exogenous variable. The framework is used to obtain evidence on the time varying response of stock prices to the monetary policy surprises. Stock prices always persistently decrease following a monetary tightening and more strongly than fundamentals imply - with an increase in risk-premia accounting for the difference. However, the response of stock prices varies over time. They decrease less during a boom and a perceived bubble period than during a recession. The findings suggest that so-called "leaning against the wind policies" may be ineffective since stock prices are less responsive during periods when such policies would disinflate asset bubbles using contractionary monetary policy. Chapter III. The third chapter augments a monetary dynamic general equilibrium model with a bubble as considered in [Miao_Wang_2015]. A bubble may exist in firms' stock market values and firms borrow against their inflated stock market values. Within this framework, I analyze the relation between monetary policy and the bubble. I find that contractionary monetary policy decreases the bubble which tightens borrowing constraints and amplifies the reaction of investment and output. These results are in contrast to the ones in Gali (2014) who considers a bubble of the classic rational type and finds that contractionary monetary policy can increase bubbles.
605

Secagem térmica de lodos de esgoto: determinação da umidade de equilíbrio. / Thermal drying of wastewater sludge: determination of equilibrium moisture.

David, Airton Checoni 25 April 2002 (has links)
O estudo apresenta os principais aspectos da operação de secagem térmica de lodos gerados em estações de tratamento de esgotos, os tipos de equipamentos disponíveis no mercado que podem ser utilizados para esse fim e o comportamento da sorção de umidade pelo material seco quando em contato com o ar ambiente. A operação de secagem térmica é uma alternativa para a diminuição do peso e volume de lodos, com conseqüente diminuição dos custos de transporte e disposição final. É considerada, também, um processo de melhoria da qualidade do lodo, pois elimina os microrganismos patogênicos e, ao mesmo tempo, preserva a matéria orgânica presente no lodo, aspectos de importância fundamental quando o lodo/biossólido seco vai ser utilizado na agricultura. Os equipamentos para secagem térmica podem ser diretos ou indiretos. Os principais tipos são: secador rotativo, de soleiras múltiplas, de leito fluidizado, por transporte pneumático e transportadores de esteira. Cada tipo possui vantagens e desvantagens em relação aos demais. A eficiência do processo de secagem térmica é influenciada por uma série de fatores, como: consumo específico de energia, tipo de equipamento utilizado e teores de umidade inicial e final do material. Nos ensaios de laboratório, mediu-se os teores de umidade de equilíbrio do lodo produzido na ETE Baureri, localizada na Região Metropolitana de São Paulo, sob diferentes condições de umidade relativa do ar ambiente. Com esses valores, obteve-se a curva de umidade de equilíbrio do material. Como resultado dessa experiência conclui-se que para cada umidade relativa do ar ambiente há um teor de umidade de equilíbrio do lodo. / The study presents the main aspects of a thermal drying operation of the sludge produced by wastewater treatment plants, the types of equipment likely to be used for this purpose and the sorption behavior of the water contents by the dry material when in contact with the air. The thermal drying operation is an alternative to reduce the weight and volume of the sludge production with a resulting decrease in transportation and final disposal costs. It is also deemed to be a process that improves the sludge quality because includes the elimination of pathogenic microorganisms while preserving the existing organic matter of the sludge, which are aspects of the utmost importance whenever the dry biosolid will be used as fertilizer in agriculture. The thermal drying equipment can be direct or indirect. The main types are: rotary dryers, multi-tray dryers, fluid bed dryers, flash dryers, and conveyor dryers. Each type presents advantages and disadvantages when compared to one another. The efficiency of the thermal drying process is affected by several aspects, such as specific consumption of energy, type of equipment used, and initial and final water contents of the material. The laboratory tests measured the equilibrium moisture contents of the sludge produced by Barueri Wastewater Treatment Plant, located in the São Paulo Metropolitan Region, under different conditions of environment relative humidity. Based on these measurements, an equilibrium moisture curve of the material was obtained. The major conclusion of the experiment was that to each environment relative humidity there is a corresponding equilibrium moisture of the sludge.
606

Keq and [delta] H for the esterification of glycine in alcohol-water systems

Artz, Susan Carol January 2011 (has links)
Photocopy of typescript. / Digitized by Kansas Correctional Industries
607

The concept of the pseudospinodal in critical phenomena

Osman, Junaidah January 2011 (has links)
Typescript (photocopy). / Digitized by Kansas Correctional Industries
608

Optimal Transport and Equilibrium Problems in Mathematical Finance

Tan, Xiaowei January 2019 (has links)
The thesis consists of three independent topics, each of which is discussed in an individual chapter. The first chapter considers a multiperiod optimal transport problem where distributions μ0, . . . , μn are prescribed and a transport corresponds to a scalar martingale X with marginals Xt ∼ μt. We introduce particular couplings called left-monotone transports; they are characterized equivalently by a no-crossing property of their support, as simultaneous optimizers for a class of bivariate transport cost functions with a Spence–Mirrlees property, and by an order-theoretic minimality property. Left-monotone transports are unique if μ0 is atomless, but not in general. In the one-period case n = 1, these transports reduce to the Left-Curtain coupling of Beiglbo ̈ck and Juillet. In the multiperiod case, the bivariate marginals for dates (0,t) are of Left-Curtain type, if and only if μ0, . . . , μn have a specific order property. The general analysis of the transport problem also gives rise to a strong duality result and a description of its polar sets. Finally, we study a variant where the intermediate marginals μ1,...,μn−1 are not prescribed. The second chapter studies the convergence of Nash equilibria in a game of optimal stopping. If the associated mean field game has a unique equilibrium, any sequence of n-player equilibria converges to it as n → ∞. However, both the finite and infinite player versions of the game often admit multiple equilibria. We show that mean field equilibria satisfying a transversality condition are limit points of n-player equilibria, but we also exhibit a remarkable class of mean field equilibria that are not limits, thus questioning their interpretation as “large n” equilibria. The third chapter studies the equilibrium price of an asset that is traded in continuous time between N agents who have heterogeneous beliefs about the state process underlying the asset’s payoff. We propose a tractable model where agents maximize expected returns under quadratic costs on inventories and trading rates. The unique equilibrium price is characterized by a weakly coupled system of linear parabolic equations which shows that holding and liquidity costs play dual roles. We derive the leading-order asymptotics for small transaction and holding costs which give further insight into the equilibrium and the consequences of illiquidity.
609

Influência da suplementação de β-alanina associada ao treinamento intervalado de alta intensidade no desempenho de sprints repetidos /

Milioni, Fabio. January 2018 (has links)
Orientador: Alessandro Moura Zagatto / Coorientador: Marcelo Papoti / Banca: Bruno Gualano / Banca: Bryan Saunders / Banca: Fúlvia de Barros Manchado Gobatto / Banca: Eduardo Zapaterra Campos / Resumo: O objetivo da presente tese foi verificar a influência da suplementação de β-Alanina associado ao treinamento intervalado de alta intensidade (HIIT) na performance de sprints repetidos. Participaram do estudo conduzido em caráter randomizado e duplo-cego, 20 jovens saudáveis alocados em dois grupos (Gβ [n = 10] - 6,4 g.dia-1 de β-Alanina; GP [n = 10] - 6,4 g.dia-1 de dextrose - placebo). Os participantes foram avaliados em três momentos distintos, previamente ao início, após quatro semanas de HIIT sem suplementação e após 6 semanas de suplementação + HIIT. As avaliações foram compostas por teste incremental até exaustão (TINC); séries de 12 sprints repetidos (RSA); e teste de tempo limite até exaustão a 115% da velocidade máxima atingida no TINC (TLIM). Previamente e imediatamente após TINC e RSA foram realizadas avaliações neuromusculares compostas por saltos verticais máximos, contrações isométricas máximas de extensão de joelho e estimulação elétrica periférica. O HIIT foi composto de dez corridas de 1 min a 90% da velocidade máxima atingida no TINC, com 1 min de recuperação passiva entre as corridas e frequência de 3 sessões semanais. Previamente ao início da suplementação + HIIT e ao final da intervenção, os participantes foram submetidos a biópsias musculares para determinação do conteúdo de carnosina intramuscular, capacidade de tamponamento in vitro e conteúdo de proteínas/enzimas chaves. Após a intervenção, ambos os grupos melhoraram o metabolismo oxidativo (i.e., co... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of the present thesis was to verify the influence of β-Alanine supplementation associated with high intensity interval training (HIIT) on the performance of repeated sprints. The study was conducted in a randomized, double-blind design and 20 healthy young men were allocated in two groups (Gβ [n = 10] - 6.4 g.day-1 of β-Alanine; GP [n = 10] - 6.4 g.day-1 of dextrose - placebo). The participants were evaluated at three different moments, prior to beginning, after four weeks of HIIT without supplementation and after 6 weeks of supplementation + HIIT. The evaluations were composed by incremental test until exhaustion (TINC); set of 12 repeated sprints (RSA); and time-to-exhaustion test at 115% of the maximum velocity achieved in TINC (TLIM). Previously and immediately after TINC and RSA, neuromuscular evaluations were performed, consisting of maximum vertical jumps, maximal voluntary isometric contractions of knee extension and peripheral electrical stimulation. The HIIT was composed by ten runs of 1-min at 90% of the maximum velocity achieved in TINC, with 1-min of passive recovery between runs and frequency of 3 sessions per week. Prior to the initiation of supplementation + HIIT and at the end of the intervention, the participants underwent muscle biopsies to determine intramuscular carnosine content, muscle buffer capacity in vitro and key protein/enzyme content. After the intervention, both groups improved oxidative metabolism (i.e., maximal oxygen uptake), however, only Gβ significantly improved the intramuscular carnosine content and the RSA variables; in addition to presenting attenuation of the neuromuscular fatigue induced by the RSA. No significant differences were observed in anaerobic capacity, muscle buffer capacity in vitro and key protein/enzyme content. Thus, the association between β-Alanine supplementation and HIIT provided significant improvement in repeated sprints performan / Doutor
610

Emulating Balance Control Observed in Human Test Subjects with a Neural Network

Hilts, Wade William 16 July 2018 (has links)
Human balance control is a complex feedback system that must be adaptable and robust in an infinitely varying external environment. It is probable that there are many concurrent control loops occurring in the central nervous system that achieve stability for a variety of postural perturbations. Though many engineering models of human balance control have been tested, no models of how these controllers might operate within the nervous system have yet been developed. We have focused on building a model of a proprioceptive feedback loop with simulated neurons. The proprioceptive referenced portion of human balance control has been successfully modeled by a PD controller with a time delay and output torque positive feedback. For this model, angular position is measured at the ankle and corrective torque is applied about the joint to maintain a vertical orientation. In this paper, we construct a neural network that performs addition, subtraction, multiplication, differentiation and signal filtering to demonstrate that a simulated biological neural system based off of the engineering control model is capable of matching human test subject dynamics.

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