International Expansion, Diversification and Regulated Firm Nonmarket Strategy

Previous studies have shown that regulated firms diversify for reasons that are different than for unregulated firms. We explore some of these differences by providing a theoretical model that starts by considering the firm-regulator relationship as an incomplete information issue, in which a regulated incumbent has knowledge that the regulator does not have, but the firm cannot convey hard information about this knowledge. The incumbent faces both market and nonmarket competition from a new entrant. In that context, we show that when the firm faces tough nonmarket competition domestically, going abroad can create a mechanism that makes information transmission to the regulator more credible. International expansion can thus be a way to solve domestic nonmarket issues in addition to being a catalyst for growth.

On the Political Economy of Sequential Reforms

This paper proposes an explanation for why efficient reforms are not carried out when losers have the power to block their implementation, even though compensating them is feasible. We construct a signaling model with two-sided incomplete information in which a government faces the task of sequentially implementing two reforms by bargaining with interest groups. The organization of interest groups is endogenous. Compensations are distortionary and government types differ in the concern about distortions. We show that, when compensations are allowed to be informative about the government’s type, there is a bias against the payment of compensations and the implementation of reforms. This is because paying high compensations today provides incentives for some interest groups to organize and oppose subsequent reforms with the only purpose of receiving a transfer. By paying lower compensations, governments attempt to prevent such interest groups from organizing. However, this comes at the cost of reforms being blocked by interest groups with relatively high losses.

In Search of Advice for Physicians in Entry-Level Medical Markets

We consider entry-level medical markets for physicians in the United Kingdom. These markets experienced failures which led to the adoption of centralized market mechanisms in the 1960's. However, different regions introduced different centralized mechanisms. We advise physicians who do not have detailed information about the rank-order lists submitted by the other participants. We demonstrate that in each of these markets in a low information environment it is not beneficial to reverse the true ranking of any two acceptable hospital positions. We further show that (i) in the Edinburgh 1967 market, ranking unacceptable matches as acceptable is not profitable for any participant and (ii) in any other British entry-level medical market, it is possible that only strategies which rank unacceptable positions as acceptable are optimal for a physician.

Essais sur la conception de mécanismes et les enchères

Cette thèse est composée de trois essais liés à la conception de mécanisme et aux enchères. Dans le premier essai j'étudie la conception de mécanismes bayésiens efficaces dans des environnements où les fonctions d'utilité des agents dépendent de l'alternative choisie même lorsque ceux-ci ne participent pas au mécanisme. En plus d'une règle d'attribution et d'une règle de paiement le planificateur peut proférer des menaces afin d'inciter les agents à participer au mécanisme et de maximiser son propre surplus; Le planificateur peut présumer du type d'un agent qui ne participe pas. Je prouve que la solution du problème de conception peut être trouvée par un choix max-min des types présumés et des menaces. J'applique ceci à la conception d'une enchère multiple efficace lorsque la possession du bien par un acheteur a des externalités négatives sur les autres acheteurs. Le deuxième essai considère la règle du juste retour employée par l'agence spatiale européenne (ESA). Elle assure à chaque état membre un retour proportionnel à sa contribution, sous forme de contrats attribués à des sociétés venant de cet état. La règle du juste retour est en conflit avec le principe de la libre concurrence puisque des contrats ne sont pas nécessairement attribués aux sociétés qui font les offres les plus basses. Ceci a soulevé des discussions sur l'utilisation de cette règle: les grands états ayant des programmes spatiaux nationaux forts, voient sa stricte utilisation comme un obstacle à la compétitivité et à la rentabilité. Apriori cette règle semble plus coûteuse à l'agence que les enchères traditionnelles. Nous prouvons au contraire qu'une implémentation appropriée de la règle du juste retour peut la rendre moins coûteuse que des enchères traditionnelles de libre concurrence. Nous considérons le cas de l'information complète où les niveaux de technologie des firmes sont de notoriété publique, et le cas de l'information incomplète où les sociétés observent en privée leurs coûts de production. Enfin, dans le troisième essai je dérive un mécanisme optimal d'appel d'offre dans un environnement où un acheteur d'articles hétérogènes fait face a de potentiels fournisseurs de différents groupes, et est contraint de choisir une liste de gagnants qui est compatible avec des quotas assignés aux différents groupes. La règle optimale d'attribution consiste à assigner des niveaux de priorité aux fournisseurs sur la base des coûts individuels qu'ils rapportent au décideur. La manière dont ces niveaux de priorité sont déterminés est subjective mais connue de tous avant le déroulement de l'appel d'offre. Les différents coûts rapportés induisent des scores pour chaque liste potentielle de gagnant. Les articles sont alors achetés à la liste ayant les meilleurs scores, s'il n'est pas plus grand que la valeur de l'acheteur. Je montre également qu'en général il n'est pas optimal d'acheter les articles par des enchères séparées.

Analyse en identification partielle de la décision d'émigrer des étudiants africains

La migration internationale d’étudiants est un investissement couteux pour les familles dans beaucoup de pays en voie de développement. Cependant, cet investissement est susceptible de générer des bénéfices financiers et sociaux relativement importants aux investisseurs, tout autant que des externalités pour d’autres membres de la famille. Cette thèse s’intéresse à deux aspects importants de la migration des étudiants internationaux : (i) Qui part? Quels sont les déterminants de la probabilité de migration? (ii) Qui paie? Comment la famille s’organise-t-elle pour couvrir les frais de la migration? (iii) Qui y gagne? Ce flux migratoire est-il au bénéfice du pays d’origine? Entreprendre une telle étude met le chercheur en face de défis importants, notamment, l’absence de données complètes et fiables; la dispersion géographique des étudiants migrants en étant la cause première. La première contribution importante de ce travail est le développement d’une méthode de sondage en « boule de neige » pour des populations difficiles à atteindre, ainsi que d’estimateurs corrigeant les possibles biais de sélection. A partir de cette méthodologie, j’ai collecté des données incluant simultanément des étudiants migrants et non-migrants du Cameroun en utilisant une plateforme internet. Un second défi relativement bien documenté est la présence d’endogénéité du choix d’éducation. Nous tirons avantage des récents développements théoriques dans le traitement des problèmes d’identification dans les modèles de choix discrets pour résoudre cette difficulté, tout en conservant la simplicité des hypothèses nécessaires. Ce travail constitue l’une des premières applications de cette méthodologie à des questions de développement. Le premier chapitre de la thèse étudie la décision prise par la famille d’investir dans la migration étudiante. Il propose un modèle structurel empirique de choix discret qui reflète à la fois le rendement brut de la migration et la contrainte budgétaire liée au problème de choix des agents. Nos résultats démontrent que le choix du niveau final d’éducation, les résultats académiques et l’aide de la famille sont des déterminants importants de la probabilité d’émigrer, au contraire du genre qui ne semble pas affecter très significativement la décision familiale. Le second chapitre s’efforce de comprendre comment les agents décident de leur participation à la décision de migration et comment la famille partage les profits et décourage le phénomène de « passagers clandestins ». D’autres résultats dans la littérature sur l’identification partielle nous permettent de considérer des comportements stratégiques au sein de l’unité familiale. Les premières estimations suggèrent que le modèle « unitaire », où un agent représentatif maximise l’utilité familiale ne convient qu’aux familles composées des parents et de l’enfant. Les aidants extérieurs subissent un cout strictement positif pour leur participation, ce qui décourage leur implication. Les obligations familiales et sociales semblent expliquer les cas de participation d’un aidant, mieux qu’un possible altruisme de ces derniers. Finalement, le troisième chapitre présente le cadre théorique plus général dans lequel s’imbriquent les modèles développés dans les précédents chapitres. Les méthodes d’identification et d’inférence présentées sont spécialisées aux jeux finis avec information complète. Avec mes co-auteurs, nous proposons notamment une procédure combinatoire pour une implémentation efficace du bootstrap aux fins d’inférences dans les modèles cités ci-dessus. Nous en faisons une application sur les déterminants du choix familial de soins à long terme pour des parents âgés.

Pregnancy in adolescents as a problem to 14 – 19 year olds in Nocaima (Cundinamarca)

Adolescent pregnancy is a current problem which raises concern due to its individual, familiar and collective consequences. Fifteen million adolescents give birth each year in the world. Abortion is the preferred option used in unwanted pregnancies. Adolescent pregnancy is frequent in Nocaima, Cundinamarca and is a community concern in this small town initiating its process of becoming a healthy municipality. As such, the community has highlighted this problem to be studied and submitted to intervention to promote a free and responsible sexuality decreasing unwanted adolescent pregnancies. Objective: To find data on contraception, pregnancy and related factors in selected adolescents therefore, improving current incomplete information. Methods: Descriptive observational study with survey application on 226 female 14 to 19 year old students from three high school facilities in Nocaima including 8th to 11th graders. Results: 88.9% of the participants were between 14 and 17 years of age. 66.8% of the adolescents claim to use correctly contraceptive methods and 28.8% have had sexual intercourse with an average initiation at age 15. 11.1% have been pregnant once in their lives and of these 57.1 % ended in induced abortion and 66.8% were school dropouts. Conclusions: After having implemented an educational campaign on healthy sex and reproductive behaviors we view adolescent pregnancy as a public health problem which is preventable and related to the deficit of social and family support as well as weakness in individual decision making.

Nature's choice? a study of the displacement of incumbents in elections

Como choques econômicos afetam eleições em democracias? Usando dados eleitorais do Congresso dos Estados Unidos, eu testo se choques adversos podem afetar desigualmente partidos incumbentes e oponentes. Esse efeito é identificado, entre vários procedimentos, por uma regressão em descontinuidade. Eu considero possibilidades teóricas para esse efeito, quando cidadãos não conseguem observar perfeitamente se a falta de bens públicos é devido a um choque adverso, ou a consumo privado do político. Quando o choque é observável, não há efeito; enquanto se não fosse, haveria. As evidências empíricas são consistentes com a teoria.

All-pay auctions with endogenous asymmetries

We study N-bidders, asymmetric all-pay auctions under incomplete information. First, we solve for the equilibrium of a parametric model. Each bidder’s valuation is independently drawn from an uniform [0, αi] where the parameter αi may vary across bidders. In this game, asymmetries are exogenously given. Next, a two-stage game where asymmetries are endogenously generated is studied. At the first stage, each bidder chooses the level of an observable, costly, value-enhancing action. The second stage is the bidding sub-game, whose equilibrium is simply the equilibrium of the, previously analyzed, game with exogenous asymmetries. Finally, natural applications of the all pay-auction in the context of political lobbying are considered: the effects of excluding bidders, as well as, the impact of caps on bids.

Bias and size effects of price-comparison search engines : theory and experimental evidence

We analyze the impact on consumer prices of the size and bias of price comparison search engines. In the context of a model related to Burdett and Judd (1983) and Varian (1980), we develop and test experimentally several theoretical predictions. The experimental results confirm the model’s predictions regarding the impact of the number of firms, and the type of bias of the search engine, but reject the model’s predictions regarding changes in the size of the index. The explanatory power of an econometric model for the price distributions is significantly improved when variables accounting for risk attitudes are introduced.

A simple analysis of the U.S. emission permits auctions

We examine a stylized version of EPA auctions when agents know the list of values of sellers and buyers. Sellers and buyers behave strategically. We show that there are two types of equilibria: inefficient equilibria where no goods are traded and efficient equilibria where alI exchange occurs at a uniform price. We also provide examples of the EPA auction game under incomplete information when the uniform price equilibrium holds and when it does not hold. When the uniform price equilibrium holds, sellers shade their bids up and buyers shade their bids down. In the example where the uniform price equilibrium does not hold, both buyers and sellers shade their bids down in an equilibrium.

Investigação farmacoepidemiológica do uso do clonazepam no distrito sanitário leste em Natal-RN

Prescription errors are the most serious type of medication errors found in the health system. The main purpose of this study was to evaluate the quality of clonazepam prescriptions. A descriptive and observational study with retrospective data collection was conducted at 30 community pharmacies in Natal/RN, Brazil, after informed consent was obtained from the pharmacists. A sample of 313 prescription notifications was randomly collected in October 2009. They were analyzed for legible handwriting and completeness. During the study, one researcher, two pharmacists, and one pharmacy undergraduate student evaluated patient and purchaser identification, pharmaceutical form, dosing regimen, administration route, and prescription by generic name. This research was approved by the institutional Ethics Committee. Among the 313 collected notifications, only 44.1% were legible. A total of 55.91% (175/313) had at least one illegible item, 100% contained incomplete information, and 97.12% (304/313) contained one or more abbreviations. The proportion of illegible handwriting related to the patient s identification (p=0.0001) was statistically significantly greater than that related to the drug purchaser s identification (p=0.0004). Contrary to legal requirements, prescriptions with the generic name accounted for 13.42% (42/313) of the total. All the examined notifications were handwritten. Prescription errors, which potentially can have serious consequences, have been evaluated worldwide, although little is known about this subject as it relates to community pharmacies. This study showed high percentages of prescribing problems, which justifies the development of future research about medication errors in community pharmacies and education activities for prescribers

Aplicação preliminar do método QRAM para avaliação de riscos para segurança ocupacional na construção civil

A segurança ocupacional é imprescindível na indústria da construção civil e a análise e avaliação de riscos para a segurança ocupacional (AARSO) é o primeiro e fundamental passo para alcançá-la, baseado na definição e implementação de programas de prevenção. A AARSO é um processo complexo, que implica a consideração e análise de muitos parâmetros quantitativos e/ou qualitativos que são difíceis de quantificar. As metodologias AARSO utilizadas na indústria da construção civil são baseadas em informação sujeita a incerteza (sendo tratada por técnicas probabilísticas e/ou estatísticas), difusa, imprecisa e/ou incompleta. Isso implica algumas limitações, como, por exemplo, obrigar os analistas a estimar parâmetros ou efetuar comparações com outros canteiros de obras (o que afasta do sistema real em estudo). O objetivo inicial deste estudo foi efetuar a pré-validação de um método AARSO, o QRAM, em duas cidades brasileiras, de médio e grande porte.

Análise dos aspectos legais das prescrições de medicamentos

This article describes a survey of prescriptions dispensed in drugstores and pharmacies in the city of Araraquara in the state of São Paulo, Brazil, in May 2006. Their contents were assessed for compliance with the laws in force on drug prescription and dispensing. A total of 1,335 prescriptions were examined: 40 (3%) were unsigned, 212 (15.9%) did not contain the prescribing physician's stamp, 170 (12.7%) were undated. There were prescriptions containing corrections (4.6%), and written in code (4.4%). Only 58.8% were legible and easy to understand; nevertheless all of them were dispensed. Some did not specify the name of the patient (7.2%). On how to use the medication prescribed, not a single prescription contained all the information required by law. Specifically, 7.6% lacked information on dosage, 54.3% on presentation, 33.6% on how to take the drug, and 51.2% on duration of treatment. The data show a general failure to comply with the laws on drug prescription and dispensing. Incomplete information on the drugs and their correct use could lead to irrational use and errors in medication. The lack of prescribers' signature and stamp, date of emission and name of patient can lead to fraudulent and counterfeit prescriptions. Thus, the data found point to the need for capacitation of prescribing and dispensing professionals and the importance of the role of professional associations in guiding their members.

Characterization of the variable cow's age at last calving as a measurement of longevity by using the Kaplan-Meier estimator and the Cox model

In most studies on beef cattle longevity, only the cows reaching a given number of calvings by a specific age are considered in the analyses. With the aim of evaluating all cows with productive life in herds, taking into consideration the different forms of management on each farm, it was proposed to measure cow longevity from age at last calving (ALC), that is, the most recent calving registered in the files. The objective was to characterize this trait in order to study the longevity of Nellore cattle, using the Kaplan-Meier estimators and the Cox model. The covariables and class effects considered in the models were age at first calving (AFC), year and season of birth of the cow and farm. The variable studied (ALC) was classified as presenting complete information (uncensored = 1) or incomplete information (censored = 0), using the criterion of the difference between the date of each cow's last calving and the date of the latest calving at each farm. If this difference was >36 months, the cow was considered to have failed. If not, this cow was censored, thus indicating that future calving remained possible for this cow. The records of 11 791 animals from 22 farms within the Nellore Breed Genetic Improvement Program ('Nellore Brazil') were used. In the estimation process using the Kaplan-Meier model, the variable of AFC was classified into three age groups. In individual analyses, the log-rank test and the Wilcoxon test in the Kaplan-Meier model showed that all covariables and class effects had significant effects (P < 0.05) on ALC. In the analysis considering all covariables and class effects, using the Wald test in the Cox model, only the season of birth of the cow was not significant for ALC (P > 0.05). This analysis indicated that each month added to AFC diminished the risk of the cow's failure in the herd by 2%. Nonetheless, this does not imply that animals with younger AFC had less profitability. Cows with greater numbers of calvings were more precocious than those with fewer calvings. Copyright © The Animal Consortium 2012.

Mathematical models of cognitive processes

The research activity carried out during the PhD course was focused on the development of mathematical models of some cognitive processes and their validation by means of data present in literature, with a double aim: i) to achieve a better interpretation and explanation of the great amount of data obtained on these processes from different methodologies (electrophysiological recordings on animals, neuropsychological, psychophysical and neuroimaging studies in humans), ii) to exploit model predictions and results to guide future research and experiments. In particular, the research activity has been focused on two different projects: 1) the first one concerns the development of neural oscillators networks, in order to investigate the mechanisms of synchronization of the neural oscillatory activity during cognitive processes, such as object recognition, memory, language, attention; 2) the second one concerns the mathematical modelling of multisensory integration processes (e.g. visual-acoustic), which occur in several cortical and subcortical regions (in particular in a subcortical structure named Superior Colliculus (SC)), and which are fundamental for orienting motor and attentive responses to external world stimuli. This activity has been realized in collaboration with the Center for Studies and Researches in Cognitive Neuroscience of the University of Bologna (in Cesena) and the Department of Neurobiology and Anatomy of the Wake Forest University School of Medicine (NC, USA). PART 1. Objects representation in a number of cognitive functions, like perception and recognition, foresees distribute processes in different cortical areas. One of the main neurophysiological question concerns how the correlation between these disparate areas is realized, in order to succeed in grouping together the characteristics of the same object (binding problem) and in maintaining segregated the properties belonging to different objects simultaneously present (segmentation problem). Different theories have been proposed to address these questions (Barlow, 1972). One of the most influential theory is the so called “assembly coding”, postulated by Singer (2003), according to which 1) an object is well described by a few fundamental properties, processing in different and distributed cortical areas; 2) the recognition of the object would be realized by means of the simultaneously activation of the cortical areas representing its different features; 3) groups of properties belonging to different objects would be kept separated in the time domain. In Chapter 1.1 and in Chapter 1.2 we present two neural network models for object recognition, based on the “assembly coding” hypothesis. These models are networks of Wilson-Cowan oscillators which exploit: i) two high-level “Gestalt Rules” (the similarity and previous knowledge rules), to realize the functional link between elements of different cortical areas representing properties of the same object (binding problem); 2) the synchronization of the neural oscillatory activity in the γ-band (30-100Hz), to segregate in time the representations of different objects simultaneously present (segmentation problem). These models are able to recognize and reconstruct multiple simultaneous external objects, even in difficult case (some wrong or lacking features, shared features, superimposed noise). In Chapter 1.3 the previous models are extended to realize a semantic memory, in which sensory-motor representations of objects are linked with words. To this aim, the network, previously developed, devoted to the representation of objects as a collection of sensory-motor features, is reciprocally linked with a second network devoted to the representation of words (lexical network) Synapses linking the two networks are trained via a time-dependent Hebbian rule, during a training period in which individual objects are presented together with the corresponding words. Simulation results demonstrate that, during the retrieval phase, the network can deal with the simultaneous presence of objects (from sensory-motor inputs) and words (from linguistic inputs), can correctly associate objects with words and segment objects even in the presence of incomplete information. Moreover, the network can realize some semantic links among words representing objects with some shared features. These results support the idea that semantic memory can be described as an integrated process, whose content is retrieved by the co-activation of different multimodal regions. In perspective, extended versions of this model may be used to test conceptual theories, and to provide a quantitative assessment of existing data (for instance concerning patients with neural deficits). PART 2. The ability of the brain to integrate information from different sensory channels is fundamental to perception of the external world (Stein et al, 1993). It is well documented that a number of extraprimary areas have neurons capable of such a task; one of the best known of these is the superior colliculus (SC). This midbrain structure receives auditory, visual and somatosensory inputs from different subcortical and cortical areas, and is involved in the control of orientation to external events (Wallace et al, 1993). SC neurons respond to each of these sensory inputs separately, but is also capable of integrating them (Stein et al, 1993) so that the response to the combined multisensory stimuli is greater than that to the individual component stimuli (enhancement). This enhancement is proportionately greater if the modality-specific paired stimuli are weaker (the principle of inverse effectiveness). Several studies have shown that the capability of SC neurons to engage in multisensory integration requires inputs from cortex; primarily the anterior ectosylvian sulcus (AES), but also the rostral lateral suprasylvian sulcus (rLS). If these cortical inputs are deactivated the response of SC neurons to cross-modal stimulation is no different from that evoked by the most effective of its individual component stimuli (Jiang et al 2001). This phenomenon can be better understood through mathematical models. The use of mathematical models and neural networks can place the mass of data that has been accumulated about this phenomenon and its underlying circuitry into a coherent theoretical structure. In Chapter 2.1 a simple neural network model of this structure is presented; this model is able to reproduce a large number of SC behaviours like multisensory enhancement, multisensory and unisensory depression, inverse effectiveness. In Chapter 2.2 this model was improved by incorporating more neurophysiological knowledge about the neural circuitry underlying SC multisensory integration, in order to suggest possible physiological mechanisms through which it is effected. This endeavour was realized in collaboration with Professor B.E. Stein and Doctor B. Rowland during the 6 months-period spent at the Department of Neurobiology and Anatomy of the Wake Forest University School of Medicine (NC, USA), within the Marco Polo Project. The model includes four distinct unisensory areas that are devoted to a topological representation of external stimuli. Two of them represent subregions of the AES (i.e., FAES, an auditory area, and AEV, a visual area) and send descending inputs to the ipsilateral SC; the other two represent subcortical areas (one auditory and one visual) projecting ascending inputs to the same SC. Different competitive mechanisms, realized by means of population of interneurons, are used in the model to reproduce the different behaviour of SC neurons in conditions of cortical activation and deactivation. The model, with a single set of parameters, is able to mimic the behaviour of SC multisensory neurons in response to very different stimulus conditions (multisensory enhancement, inverse effectiveness, within- and cross-modal suppression of spatially disparate stimuli), with cortex functional and cortex deactivated, and with a particular type of membrane receptors (NMDA receptors) active or inhibited. All these results agree with the data reported in Jiang et al. (2001) and in Binns and Salt (1996). The model suggests that non-linearities in neural responses and synaptic (excitatory and inhibitory) connections can explain the fundamental aspects of multisensory integration, and provides a biologically plausible hypothesis about the underlying circuitry.