Trade Shocks and Local Labor Markets' Linkages: Theory and Evidence

In the past few years, there has been a concern among economists and policy makers that increased openness to international trade affects some regions in a country more than others. Recent research has found that local labor markets more exposed to import competition through their initial employment composition experience worse outcomes in several dimensions such as, employment, wages, and poverty. Although there is evidence that regions within a country exhibit variation in the intensity with which they trade with each other and with other countries, trade linkages have been ignored in empirical analyses of the regional effects of trade, which focus on differences in employment composition. In this dissertation, I investigate how local labor markets' trade linkages shape the response of wages to international trade shocks. In the second chapter, I lay out a standard multi-sector general equilibrium model of trade, where domestic regions trade with each other and with the rest of the world. Using this benchmark, I decompose a region's wage change resulting from a national import cost shock into a direct effect on prices, holding other endogenous variables constant, and a series of general equilibrium effects. I argue the direct effect provides a natural measure of exposure to import competition within the model since it summarizes the effect of the shock on a region's wage as a function of initial conditions given by its trade linkages. I call my proposed measure linkage exposure while I refer to the measures used in previous studies as employment exposure. My theoretical analysis also shows that the assumptions previous studies make on trade linkages are not consistent with the standard trade model. In the third chapter, I calibrate the model to the Brazilian economy in 1991--at the beginning of a period of trade liberalization--to perform a series of experiments. In each of them, I reduce the Brazilian import cost by 1 percent in a single sector and I calculate how much of the cross-regional variation in counterfactual wage changes is explained by exposure measures. Over this set of experiments, employment exposure explains, for the median sector, 2 percent of the variation in counterfactual wage changes while linkage exposure explains 44 percent. In addition, I propose an estimation strategy that incorporates trade linkages in the analysis of the effects of trade on observed wages. In the model, changes in wages are completely determined by changes in market access, an endogenous variable that summarizes the real demand faced by a region. I show that a linkage measure of exposure is a valid instrument for changes in market access within Brazil. By using observed wage changes in Brazil between 1991-2000, my estimates imply that a region at the 25th percentile of the change in domestic market access induced by trade liberalization, experiences a 0.6 log points larger wage decline (or smaller wage increase) than a region at the 75th percentile. The estimates from a regression of wages changes on exposure imply that a region at the 25th percentile of exposure experiences a 3 log points larger wage decline (or smaller wage increase) than a region at the 75th percentile. I conclude that estimates based on exposure overstate the negative impact of trade liberalization on wages in Brazil. In the fourth chapter, I extend the standard model to allow for two types of workers according to their education levels: skilled and unskilled. I show that there is substantial variation across Brazilian regions in the skill premium. I use the exogenous variation provided by tariff changes to estimate the impact of market access on the skill premium. I find that decreased domestic market access resulting from trade liberalization resulted in a higher skill premium. I propose a mechanism to explain this result: that the manufacturing sector is relatively more intensive in unskilled labor and I show empirical evidence that supports this hypothesis.

Capability presence in the newly internationalizing firm

We investigate the enablers of early internationalization of the firm. We posit that for firms to internationalize early in their lifecycles, sets of capabilities must be present at the firm’s formative stage and that these capabilities build upon routines that the founders bring into the new firm. These capabilities are aligned to establish a platform for internationalization unencumbered by the administrative heritage often observed in well-established firms. We model this phenomenon, testing it in a cross-national setting of early internationalizing firms in Australia and the United States. To do so, we draw upon a dynamic capabilities framing, conceptualizing and measuring the dynamic capabilities that founders apply in their early internationalization activities.

Small firm internet adoption: opportunities forgone, a journey not begun

This paper explores the endeavours of five small firms to develop web-based commerce capabilities within their existing operations. The focus is upon the strategic acquisition and exploitation of knowledge which underpins new value creating activates related to web-based commerce. A normative web-based commerce adoption model developed from a review of the extant literature related to electronic marketing, entrepreneurship, and the diffusion of new innovations was empirically tested. A multiple case study design enabled the exploration of contemporary marketing and entrepreneurship issues within the real life context of five small firms. The model aimed to emphasis best-practice adoption methods emphasizing the value of a firm's market orientation and entrepreneurial capabilities. A preliminary test of the model's theoretical contentions lent support to its overall focus, but found that the firm's existing learning capabilities were diminished during the adoption of web-based commerce, and that a lack of vision and prior knowledge produced sub-optimal adoption outcomes.

非均质材料损伤破坏的数值模拟软件开发及强韧化机理研究

本文针对平面链网模型与空间链网模型，发展了模拟非均质材料的数值软件，旨在分析材料的损伤破坏特征，寻找材料细观结构同宏观力学行为之间的相互联系，探讨材料强韧化机理以及评估材料的力学性能。采用可视化技术设计的具有交互式功能的图象用户界面，能根据具体材料对象构造特定材料模型来分析其力学行为与服役能力。初步结果表明，无论是材料弹性阶段的性质还是损伤演化阶段材料中裂纹的萌生、扩展、汇集和材料的最终失效等现象都与已有的理论结果及试验结果符合得很好。另外，本文还对材料的强韧化机理作了探索。

A unified framework for measuring preferences for schools and neighborhoods

This paper develops a framework for estimating household preferences for school and neighborhood attributes in the presence of sorting. It embeds a boundary discontinuity design in a heterogeneous residential choice model, addressing the endogeneity of school and neighborhood characteristics. The model is estimated using restricted-access Census data from a large metropolitan area, yielding a number of new results. First, households are willing to pay less than 1 percent more in house prices - substantially lower than previous estimates - when the average performance of the local school increases by 5 percent. Second, much of the apparent willingness to pay for more educated and wealthier neighbors is explained by the correlation of these sociodemographic measures with unobserved neighborhood quality. Third, neighborhood race is not capitalized directly into housing prices; instead, the negative correlation of neighborhood percent black and housing prices is due entirely to the fact that blacks live in unobservably lower-quality neighborhoods. Finally, there is considerable heterogeneity in preferences for schools and neighbors, with households preferring to self-segregate on the basis of both race and education. © 2007 by The University of Chicago. All rights reserved.

Vertical R&D Sprillovers, Cooperation, Market Structure, and Innovation.

This paper studies vertical R&D spillovers between upstream and downstream firms. The model incorporates two vertically related industries, with horizontal spillovers within each industry and vertical spillovers between the two industries. Four types of R&D cooperation are studied : no cooperation, horizontal cooperation, vertical cooperation, and simultaneous horizontal and vertical cooperation. Vertical spillovers always increase R&D and welfare, while horizontal spillovers may increase or decrease them. The comparison of cooperative settings in terms of R&D shows that no setting uniformly dominates the others. Which type of cooperation yields more R&D depends on horizontal and vertical spillovers, and market structure. The ranking of cooperative structures hinges on the signs and magnitudes of three competitive externalities (vertical, horizontal, and diagonal) which capture the effect of the R&D of a firm on the profits of other firms. One of the basic results of the strategic investment literature is that cooperation between competitors increases (decreases) R&D when horizontal spillovers are high (low); the model shows that this result does not necessarily hold when vertical spillovers and vertical cooperation are taken into account. The paper proposes a theory of innovation and market structure, showing that the relation between innovation and competition depends on horizontal spillovers, vertical spillovers, and cooperative settings. The private incentives for R&D cooperation are addressed. It is found that buyers and sellers have divergent interests regarding the choice of cooperative settings and that spillovers increase the likelihood of the emergence of cooperation in a decentralized equilibrium.

Les recherches cliniques Nord/Sud : des recherches équitables ?

Section des étudiants / Student's section

Essais sur des questions internationales en économie des ressources naturelles

Cette thèse s'articule autour de trois essais portant sur des questions internationales en économie des ressources naturelles. Le premier essai examine la production et l'échange des ressources non-renouvelables dans un modèle spatial et souligne le rôle de la superficie des pays et du coût des transports dans la détermination du sens de l'échange. Le deuxième essai considère le tarif d'extraction de la rente de rareté liée aux ressources naturelles non-renouvelables avec le modèle spatial développé dans premier essai. Le cadre spatial (plus général) permet de représenter des pays qui sont à la fois importateurs et producteurs de la ressource, ce qui n'est pas possible dans les modèles traditionnels de commerce international où les pays sont traités comme des points (sans dimension). Le troisième essai aborde la question des droits de propriétés sur les zones maritimes et examine l'allocation d'une population de pêcheurs entre les activités productives et non-productives dans une communauté côtière. Le premier chapitre propose un modèle spatial de commerce international des ressources non-renouvelables. Le cadre spatial considère explicitement la différence de taille géographique (superficie) entre les pays et permet ainsi de tenir compte du fait que les gisements naturels et leurs utilisateurs soient dispersés dans l'espace, même à l'intérieur d'un pays. En utilisant un modèle spatial à la Hotelling, nous examinons l'évolution dans le temps du sens de l'échange entre deux pays (ou régions) qui diffèrent du point de vue de leur technologie de production, de leur superficie et de leur dotation en gisement d'une ressource naturelle non-renouvelable. Le chapitre met en évidence le rôle de la taille géographique dans la détermination du sens de l'échange, à côté des explications traditionnelles que sont l'avantage comparatif et les dotations des facteurs. Notre analyse est fondamentalement différente des autres contributions dans la littérature sur le commerce international des ressources naturelles parce qu'elle souligne l'importance de la taille géographique et du coût de transport par rapport à d'autres facteurs dans la détermination des flux de ressource à l'équilibre. Le coût unitaire de transport joue un rôle capital pour déterminer si la différence de superficie entre les pays influence le sens de l'échange à l'équilibre plus que les autres facteurs. Le chapitre discute aussi du caractère régional des échanges qui a été observé pour certaines ressources telles que le minerai de fer et la bauxite. Le chapitre deux aborde la question de la répartition de la rente de rareté liée aux ressources naturelles non-renouvelables entre les pays producteurs et les pays consommateurs. Cette question a été abordée dans la littérature sous une hypothèse quelque peu restrictive. En effet, dans la plupart des travaux portant sur ce sujet le pays importateur est automatiquement considéré comme dépourvu de gisement et donc non producteur de la ressource. Pourtant la réalité est qu'il existe des ressources pour lesquelles un pays est à la fois producteur et importateur. Le cadre d'analyse de ce second essai est le modèle spatial développé dans le premier essai, qui permet justement qu'un pays puisse être à la fois importateur et producteur de la ressource. Le pays importateur détermine alors simultanément le tarif optimal et le taux d'extraction de son propre stock. Nous montrons que le tarif optimal croît au taux d'intérêt et de ce fait, ne crée aucune distorsion sur le sentier d'extraction de la ressource. Le tarif optimal permet de récupérer toute la rente lorsque le pays exportateur ne consomme pas la ressource. Néanmoins, la possibilité pour le pays exportateur de consommer une partie de son stock limite la capacité du pays importateur à récupérer la rente chez le pays exportateur. La présence de gisements de la ressource dans le pays importateur réduit la rente du pays exportateur et de ce fait renforce la capacité du pays importateur à récupérer la rente chez le pays exportateur. Le tarif initial est une fonction décroissante du stock de ressource dans le pays importateur. Cet essai aborde également la question de la cohérence dynamique du tarif obtenu avec la stratégie en boucle ouverte. Le troisième chapitre examine un problème d'allocation de l'effort entre les activités productives (par exemple la pêche) et les activités non productives (par exemple la piraterie maritime) dans une population de pêcheurs. La répartition de la population entre les activités de pêche et la piraterie est déterminée de façon endogène comme une conséquence du choix d'occupation. Nous établissons l'existence d'une multiplicité d'équilibres et mettons en évidence la possibilité d'une trappe de piraterie, c'est-à-dire un équilibre stable où une partie de la population est engagée dans les actes de piraterie. Le modèle permet d'expliquer l'augmentation significative des attaques de piraterie dans le Golfe d'Aden au cours des dernières années. Le chapitre discute aussi des différents mécanismes pour combattre la piraterie et souligne le rôle crucial des droits de propriété.

Pharmaceutical innovation, reference pricing and therapeutic classes

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REPETRO - Regime Aduaneiro Especial de Importação e Exportação de Bens Destinados à Pesquisa e Lavra de Petróleo e Gás: análise dos entraves e propostas de soluções

REPETRO, the special tax regime for importing and exporting goods for the exploration and drilling of oil and gas, aims at bringing foreign assets to Brazil enjoying a suspension or even an exemption of taxes, so that Brazilian industry may profit from about 8 billion American dollars in investments. The creation of normative devices as well as the management of the REPETRO model are under the exclusive responsibility of the Brazilian Internal Revenue Services. REPETRO was created in 1999 and is composed of the following customs treatments: importation of goods with suspension of taxes by use of the drawback special regime, suspension mode for national exporting industry; exportation with fictitious exit for the national industry; temporary admission of goods or assets used in oil exploration and production, attending to the needs of both the national and foreign market. Considering the inability of the Brazilian government in restructuring its foreign trade model so that a strong investment in technology could provide for the sector¿s needs, we must ask how we can change REPETRO to help the various companies in the oil business? The issue is very important for one of our main economic activities, though not enough studied. The energy sector has a strategic importance for the development and the economic independence of any country. The winds of globalization lead Brazil to open its economy in the last decade and the national policy for exploration and drilling (E&D) was altered. The government created a new agency dedicated to market control and energy policies, the National Agency for Oil and Biofuels (ANP). With the opening of the market, Petróleo Brasileiro S.A. - Petrobras, the Brazilian giant, lost the monopoly of the oil business. The P-50 Platform, with a capacity for 180,000 barrels per day, was imported based on REPETRO. When it began operating on April 21st, 2006, Brazil achieved self-sufficiency in oil production. The present work intends to estimate the main variables affecting the importation and exportation of goods and assets for E&D, showing how REPETRO works. We also intend to look at the results yielded by the REPETRO model for the development of the production of oil and gas in Brazil, as well as show proposals for its modernization. It has been established that even though since its implementation the REPETRO model has brought fiscal advantages through the reduction of tax costs relating to foreign commerce operations and the incentive of investments in the E&D area with the increase in the national oil production there remain the following limitations: lack of preparation and of knowledge of the model; lack of adjustement of the model to the reality of actitity of E&D of oil and gas; taxes over the pre-operational stage or investment in oil production stage; non-allowance of full access by the national industry to the supply of goods and products relating to the industrialization of goods allowed by REPETRO; other fiscal and administrative difficulties. We conclude that the REPETRO model is important for the development of the area of E&D of oil and gas, but not completely effective. It is necessary to change it or create a new model based on a new perspective of the customs treatment of the activities of exploration and production, minimizing administrative procedures relating to the operations of exportation and importation.

Especificação e implementação de um modelo assíncrono para replicação, propagação e conciliação de bases de dados distribuídas

This graduate thesis proposes a model to asynchronously replicate heterogeneous databases. This model singularly combines -in a systematic way and in a single project -different concepts, techniques and paradigms related to the areas of database replication and management of heterogeneous databases. One of the main advantages of the replication is to allow applications to continue to process information, during time intervals when they are off the network and to trigger the database synchronization, as soon as the network connection is reestablished. Therefore, the model introduces a communication and update protocol that takes in consideration the environment of asynchronous characteristics used. As part of the work, a tool was developed in Java language, based on the model s premises in order to process, test, simulate and validate the proposed model

Modelagem espaço-temporal da colonização de macrófitas submersas no reservatório de Taquaruçu

Pós-graduação em Ciências Cartográficas - FCT

Produção de celulases fúngicas por fermentação em estado sólido: ampliação de escala de biorreatores de leito fixo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Genotype x environment interaction for age at first calving, scrotal circumference, and yearling weight in Nellore cattle using reaction norms in multitrait random regression models

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Development of Clinical Decision Support Systems based on Mathematical Models of Physiological Systems

In the last years of research, I focused my studies on different physiological problems. Together with my supervisors, I developed/improved different mathematical models in order to create valid tools useful for a better understanding of important clinical issues. The aim of all this work is to develop tools for learning and understanding cardiac and cerebrovascular physiology as well as pathology, generating research questions and developing clinical decision support systems useful for intensive care unit patients. I. ICP-model Designed for Medical Education We developed a comprehensive cerebral blood flow and intracranial pressure model to simulate and study the complex interactions in cerebrovascular dynamics caused by multiple simultaneous alterations, including normal and abnormal functional states of auto-regulation of the brain. Individual published equations (derived from prior animal and human studies) were implemented into a comprehensive simulation program. Included in the normal physiological modelling was: intracranial pressure, cerebral blood flow, blood pressure, and carbon dioxide (CO2) partial pressure. We also added external and pathological perturbations, such as head up position and intracranial haemorrhage. The model performed clinically realistically given inputs of published traumatized patients, and cases encountered by clinicians. The pulsatile nature of the output graphics was easy for clinicians to interpret. The manoeuvres simulated include changes of basic physiological inputs (e.g. blood pressure, central venous pressure, CO2 tension, head up position, and respiratory effects on vascular pressures) as well as pathological inputs (e.g. acute intracranial bleeding, and obstruction of cerebrospinal outflow). Based on the results, we believe the model would be useful to teach complex relationships of brain haemodynamics and study clinical research questions such as the optimal head-up position, the effects of intracranial haemorrhage on cerebral haemodynamics, as well as the best CO2 concentration to reach the optimal compromise between intracranial pressure and perfusion. We believe this model would be useful for both beginners and advanced learners. It could be used by practicing clinicians to model individual patients (entering the effects of needed clinical manipulations, and then running the model to test for optimal combinations of therapeutic manoeuvres). II. A Heterogeneous Cerebrovascular Mathematical Model Cerebrovascular pathologies are extremely complex, due to the multitude of factors acting simultaneously on cerebral haemodynamics. In this work, the mathematical model of cerebral haemodynamics and intracranial pressure dynamics, described in the point I, is extended to account for heterogeneity in cerebral blood flow. The model includes the Circle of Willis, six regional districts independently regulated by autoregulation and CO2 reactivity, distal cortical anastomoses, venous circulation, the cerebrospinal fluid circulation, and the intracranial pressure-volume relationship. Results agree with data in the literature and highlight the existence of a monotonic relationship between transient hyperemic response and the autoregulation gain. During unilateral internal carotid artery stenosis, local blood flow regulation is progressively lost in the ipsilateral territory with the presence of a steal phenomenon, while the anterior communicating artery plays the major role to redistribute the available blood flow. Conversely, distal collateral circulation plays a major role during unilateral occlusion of the middle cerebral artery. In conclusion, the model is able to reproduce several different pathological conditions characterized by heterogeneity in cerebrovascular haemodynamics and can not only explain generalized results in terms of physiological mechanisms involved, but also, by individualizing parameters, may represent a valuable tool to help with difficult clinical decisions. III. Effect of Cushing Response on Systemic Arterial Pressure. During cerebral hypoxic conditions, the sympathetic system causes an increase in arterial pressure (Cushing response), creating a link between the cerebral and the systemic circulation. This work investigates the complex relationships among cerebrovascular dynamics, intracranial pressure, Cushing response, and short-term systemic regulation, during plateau waves, by means of an original mathematical model. The model incorporates the pulsating heart, the pulmonary circulation and the systemic circulation, with an accurate description of the cerebral circulation and the intracranial pressure dynamics (same model as in the first paragraph). Various regulatory mechanisms are included: cerebral autoregulation, local blood flow control by oxygen (O2) and/or CO2 changes, sympathetic and vagal regulation of cardiovascular parameters by several reflex mechanisms (chemoreceptors, lung-stretch receptors, baroreceptors). The Cushing response has been described assuming a dramatic increase in sympathetic activity to vessels during a fall in brain O2 delivery. With this assumption, the model is able to simulate the cardiovascular effects experimentally observed when intracranial pressure is artificially elevated and maintained at constant level (arterial pressure increase and bradicardia). According to the model, these effects arise from the interaction between the Cushing response and the baroreflex response (secondary to arterial pressure increase). Then, patients with severe head injury have been simulated by reducing intracranial compliance and cerebrospinal fluid reabsorption. With these changes, oscillations with plateau waves developed. In these conditions, model results indicate that the Cushing response may have both positive effects, reducing the duration of the plateau phase via an increase in cerebral perfusion pressure, and negative effects, increasing the intracranial pressure plateau level, with a risk of greater compression of the cerebral vessels. This model may be of value to assist clinicians in finding the balance between clinical benefits of the Cushing response and its shortcomings. IV. Comprehensive Cardiopulmonary Simulation Model for the Analysis of Hypercapnic Respiratory Failure We developed a new comprehensive cardiopulmonary model that takes into account the mutual interactions between the cardiovascular and the respiratory systems along with their short-term regulatory mechanisms. The model includes the heart, systemic and pulmonary circulations, lung mechanics, gas exchange and transport equations, and cardio-ventilatory control. Results show good agreement with published patient data in case of normoxic and hyperoxic hypercapnia simulations. In particular, simulations predict a moderate increase in mean systemic arterial pressure and heart rate, with almost no change in cardiac output, paralleled by a relevant increase in minute ventilation, tidal volume and respiratory rate. The model can represent a valid tool for clinical practice and medical research, providing an alternative way to experience-based clinical decisions. In conclusion, models are not only capable of summarizing current knowledge, but also identifying missing knowledge. In the former case they can serve as training aids for teaching the operation of complex systems, especially if the model can be used to demonstrate the outcome of experiments. In the latter case they generate experiments to be performed to gather the missing data.