In this thesis, we analyse the relationship between the hedging activities and return on equity, and the relationship between profit on hedging and other factors. Fully conditional specification is used to impute the missing values. Instrumental variable estimation and finite mixture of regression models are then used to predict the return on equity and hedging gain. We find the instrumental variable estimation is better than the OLS estimation to deal with the hedging data since it eliminates the endogeneity. By finite mixture of regression models, we show that different firms have different hedging strategies, which cause different profits in hedging. We also find the companies with large total assets prefer to hedge.

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La logique contemporaine a connu de nombreux développements au cours de la seconde moitié du siècle dernier. Le plus sensationnel est celui de la logique modale et de sa sémantique des mondes possibles (SMP) dû à Saul Kripke dans les années soixante. Ces dans ce cadre que David Lewis exposera sa sémantique des contrefactuels (SCF). Celle-ci constitue une véritable excroissance de l’architecture kripkéenne. Mais sur quoi finalement repose l’architecture kripkéenne elle-même ? Il semble bien que la réponse soit celle d’une ontologie raffinée ultimement basée sur la notion de mondes possible. Ce mémoire comporte quatre objectifs. Dans un premier temps, nous allons étudier ce qui distingue les contrefactuels des autres conditionnels et faire un survol historique de la littérature concernant les contrefactuels et leur application dans différent champs du savoir comme la philosophie des sciences et l’informatique. Dans un deuxième temps, nous ferons un exposé systématique de la théorie de Lewis telle qu’elle est exposée dans son ouvrage Counterfactuals. Finalement, nous allons explorer la fondation métaphysique des mondes possible de David Lewis dans son conception de Réalisme Modal. / Modern logic since the end of the Second World War has undergone many developments. Two of the most interesting of these are the Kripkian Possible World Semantics and Lewis’ system of Counterfactuals. The first was developed by Saul Kripke in the 1960s and the second was developed by David Lewis in the 1970s. In some senses we can say that Lewis’ system of counterfactuals or Counter Factual Semantics (CFS) is built on top of the architecture which Kripke created with his Possible Worlds Semantics (PWS). But, what is the Kripkian Possible World Semantics itself built on? The answer it seems is very finely tuned ontology founded on the notion of possible worlds. This paper will attempt to do the following. First, attempt to draw a distinction between on the one hand conditionals and the other counterfactuals and at the same time attempt to look at some of the historical literature surrounding counterfactuals and their application in various fields like the philosophy of science. Second, recapitulate Lewis’ system of counterfactual semantics as developed primarily in Lewis’ book Counterfactuals. Finally this paper will attempt to explore the metaphysical foundations of the possible worlds account argued for by David Lewis in his conception of Modal Realism.

This dissertation consists of three essays. In the first essay, I estimate a high dimensional covariance matrix of returns for 88 individual stocks from the S&P 100 index, using daily return data for 1995-2005. This study applies the two-step estimator of the dynamic conditional correlation multivariate GARCH model, proposed by Engle (2002b) and Engle and Sheppard (2001) and applies variations of this model. This is the first study estimating variances and covariances of returns using a large number of individual stocks (e.g., Engle and Sheppard (2001) use data on various aggregate sub-indexes of stocks). This avoids errors in estimation of GARCH models with contemporaneous aggregation of stocks (e.g. Nijman and Sentana 1996; Komunjer 2001). Second, this is the first multivariate GARCH adopting a systematic general-to-specific approach to specification of lagged returns in the mean equation. Various alternatives to simple GARCH are considered in step one univariate estimation, and econometric results favour an asymmetric EGARCH extension of Engle and Sheppard’s model. In essay two, I aggregate a variance-covariance matrix of return risk (estimated using DCC-MVGARCH in essay one) to an aggregate index of return risk. This measure of risk is compared with the standard approach to measuring risk from a simple univariate GARCH model of aggregate returns. In principle the standard approach implies errors in estimation due to contemporaneous aggregation of stocks. The two measures are compared in terms of correlation and economic values: measures are not perfectly correlated, and the economic value for the improved estimate of risk as calculated here is substantial. Essay three has three parts. The major part is an empirical study of the aggregate risk return tradeoff for U.S. stocks using daily data. Recent research indicates that past risk-return studies suffer from inadequate sample size, and this suggests using daily rather than monthly data. Modeling dynamics/lags is critical in daily models, and apparently this is the first such study to model lags correctly using a general to specific approach. This is also the first risk return study to apply Wu tests for possible problems of endogeneity/measurement error for the risk variable. Results indicate a statistically significant positive relation between expected returns and risk, as is predicted by capital asset pricing models. Development of the Wu test leads naturally into a model relating aggregate risk of returns to economic variables from the risk return study. This is the first such model to include lags in variables based on a general to specific methodology and to include covariances of such variables. I also derive coefficient links between such models and risk-return models, so in theory these models are more closely related than has been realized in past literature. Empirical results for the daily model are consistent with theory and indicate that the economic and financial variables explain a substantial part of variation in daily risk of returns. The first section of this essay also investigates at a theoretical and empirical level several alternative index number approaches for aggregating multivariate risk over stocks. The empirical results indicate that these indexes are highly correlated for this data set, so only the simplest indexes are used in the remainder of the essay.

This paper examines the synchronization of business cycles across the G7 countries during US recessions since the 1870s. Using a dynamic measure of correlations, results depend on the globalization period under consideration. During the 2007-2009 recession, business cycles co-movements increased to unprecedented levels. (author's abstract)

The main theme of this dissertation is the study of polytopes arising from binary multi-way contingency tables and characteristic imsets for Bayesian networks. Firstly, we study on three-way tables whose entries are independent Bernoulli ran- dom variables with canonical parameters under no three-way interaction generalized linear models. Here, we use the sequential importance sampling (SIS) method with the conditional Poisson (CP) distribution to sample binary three-way tables with the sufficient statistics, i.e., all two-way marginal sums, fixed. Compared with Monte Carlo Markov Chain (MCMC) approach with a Markov basis (MB), SIS procedure has the advantage that it does not require expensive or prohibitive pre-computations. Note that this problem can also be considered as estimating the number of lattice points inside the polytope defined by the zero-one and two-way marginal constraints. The theorems in Chapter 2 give the parameters for the CP distribution on each column when it is sampled. In this chapter, we also present the algorithms, the simulation results, and the results for Samson’s monks data. Bayesian networks, a part of the family of probabilistic graphical models, are widely applied in many areas and much work has been done in model selections for Bayesian networks. The second part of this dissertation investigates the problem of finding the optimal graph by using characteristic imsets, where characteristic imsets are defined as 0-1 vector representations of Bayesian networks which are unique up to Markov equivalence. Characteristic imset polytopes are defined as the convex hull of all characteristic imsets we consider. It was proven that the problem of finding optimal Bayesian network for a specific dataset can be converted to a linear programming problem over the characteristic imset polytope [51]. In Chapter 3, we first consider characteristic imset polytopes for all diagnosis models and show that these polytopes are direct product of simplices. Then we give the combinatorial description of all edges and all facets of these polytopes. At the end of this chapter, we generalize these results to the characteristic imset polytopes for all Bayesian networks with a fixed underlying ordering of nodes. Chapter 4 includes discussion and future work on these two topics.

Parasite control is important to horse health and horse owners should feel highly concerned about the proper treatment of parasites. In the past 30 years, veterinary science has made important advances in treating parasites and provided new products and strategies to optimize treatment and prevention. However, horse owners and managers have been slow to adopt these new recommendations. This study investigates why the transition has not occurred as expected. It examines issues related to the decision-making process of horse owners and managers as they relate to deworming strategies. In addition, it investigates current deworming approaches as well as attitudes towards alternative parasite control strategies, and tries to describe the financial considerations corresponding to each strategy. To this end, a questionnaire was distributed to Thoroughbred farms in Kentucky. The first part of the questionnaire examined the actual approaches of farm managers and characterized the Kentucky Thoroughbred farms. Most farm managers appear to be concerned about drug resistance in parasites and incorporated veterinarian advice in defining their deworming program; however, almost three-quarters of them were still following the traditional rotational deworming program. Based on a conjoint experiment, we were able to evaluate the willingness-to-pay of farm managers for different attributes of a deworming strategy – time and effort spent, decrease in health risks, drug resistance in parasites, and price. The study showed that farm managers were willing to pay a premium for a strategy that is guaranteed “non-resistant” and that decreased health risk by 5%, while they expected a discount for a strategy that requires much time and effort.

Background: While substantial progress has been made globally towards achieving United Nations Millennium Development Goal 4 (MDG 4) on child mortality, the decline is not sufficient to reach the targets set for 2015. The South Asian region, which includes India, was to achieve the MDG 4 target of 39 deaths per 1000 live births by 2015 but was estimated to have reached only 61 by 2011. A part of this under-achievement is due to the gender-differentials in child mortality in South-Asia. The inherent biological advantage of girls, reflected inlower mortality rates as compared to boys globally, is neutralized by their sociocultural disadvantage in India. The availability of technology for prenatal sex determination has promoted sex-linked abortions. Current government efforts include a law that regulates the use of ultrasound and other diagnostic techniquesfor prenatal testing of sex and a conditional cash transfer (CCT) scheme thatinvests a certain amount of funds at the birth of a girl child to attain maturity when the girl turns 18 years of age. This thesis describes the trends in genderspecific mortality during the period 1992-2011 and gender differentials in causes of death among children (paper I), compares gender differentials in child survivalby socio-economic status of the family (paper II), explores the contribution of non-specific effects of diphtheria-tetanus-pertussis (DTP) vaccination to the excess mortality among girls (paper III), and evaluates the impact of CCT schemes of the government and explores community attitudes and practices related to discrimination of girls (paper IV). Methods and Results: This study is set in Ballabgarh Health and DemographicSurveillance System (HDSS) of Haryana State in North India that covered a population of 88,861 across 28 villages in 2011. This study uses the electronic database that houses all individuals enumerated in the HDSS for the period 1992-2011 along with other demographic, socio-economic and health utilization variables. Sex ratio at birth (SRB) was adverse for girls throughout the study period, varying between 821 to 866 girls per 1000 boys. Overall, under-five mortality rates during the period 1992-2011 remained stagnant due to the increasing neonatal mortality rate and decreasing mortality in subsequent age groups. Mortality rates among girls were 1.6 to 2 times higher than boys during the post-neonatal period (1-11 months) as well as in the 1-4 year age group. Girls reported significantly higher mortality rates due to prematurity (relative risk of 1.52; 95% CI = 1.01-2.29); diarrhoea (2.29;1.59-3.29), and malnutrition (3.37; 2.05-5.53) during 2002-2007. The SRB and neonatal mortality rate were consistently adverse for girls in the advantaged groups. In the 1-36 month age group, girl children had higher mortality than boys in all SES groups. The age at vaccination for and coverage with ivabstractBacillus Calmette–Guérin, DTP, polio and measles vaccines did not differ by sex. There was significant excess mortality among girls as compared to boys in the period after immunization with DTP, for both primary (hazard ratio of 1.65; 95% CI 1.17-2.32) and DTPb (2.21; 1.24-3.93) vaccinations until the receipt of the next vaccine. No significant excess mortality among girls was noted after exposure to BCG (1.06; 0.67-1.67) or measles (1.34; 0.85-2.12) vaccine. A community survey showed poor awareness of specific government schemes for girl children. Four-fifths of the community wanted government to help families with girl children financially. In-depth interviews of government programme implementers revealed the themes of “conspiracy of silence” that was being maintained by general population, underplaying of the pervasiveness of the problem coupled with a passive implementation of the programme and “a clash between politicians trying to cash in on the public sentiment of need for subsidies for girl children and a bureaucratic approachof accountability which imposed lot of conditionalities and documentations to access these benefits”. While there has been some improvement in investment in girl children for immunization and education during the period 1992 to 2010, these were also seen among boys of the same houses and daughters in-laws who come from outside the state where such schemes are not in place. Conclusions: In the study area, girl children continue to be disadvantaged a tall periods in their childhood including in utero. In the short run, empowerment of individuals by education and increasing wealth without a concomitant change in culture of son-preference is harmful as it promotes the use of sex determination technology and female feticide to achieve desired family size and composition. There is a need to carefully review the use of health-enhancing technologies including vaccines so that they do not cause more harm to society. Current government efforts to address the gender imbalance are not working, as these are not rooted in a larger social context.

Syftet med denna avhandling är att öka kunskapen om varför villkorade tillstånd inte leder till att en lag fullt ut implementeras. Den lagstiftning som reglerar industriella verksamheter innehåller ofta generella principer. Dessa ska vägleda myndigheten i att balansera verksamhetens nytta mot eventuella negativa effekter. Tillstånd att bedriva en viss verksamhet är en värdefull rättighet för verksamhetsutövaren, men samtidigt är tillstånd villkorade och förenade med kostnader för denne, t.ex. för att begränsa utsläpp. Studier av exempelvis miljölagstiftning visar att villkorade tillstånd har bidragit till att uppfylla lagstiftningens huvudsakliga intention, men att genomförandet ofta kännetecknas av att lagstiftningens krav modifieras. I praktiken är villkorade tillstånd ett resultat av förhandlingar mellan myndigheten och verksamheten. Ett skäl till att myndigheten inleder förhandlingar är att tillämpning av lagen kräver kompletterande information om verksamheten. Ett annat skäl är att det är kostsamt för myndigheten att kontrollera tillstånds efterlevnad samt att beivra deras överträdelser. Den analytiska ansatsen är analogin mellan ett villkorat tillstånd och ett kontrakt i principal-agent teorin. Ett huvudresultat är att denna teori är lämplig för att studera villkorade tillstånd. I avhandlingen studeras olika svårigheter för myndigheten att genomföra lagstiftningen. Fokus riktas mot asymmetrisk information, men dessutom behandlas förhandlingsstyrka, politiska påtryckningar samt möjligheten att överträda tillståndsvillkor. Studierna visar att dessa förhållanden kan förklara brister vid lagstiftningens genomförande. Myndigheten kan dock begränsa konsekvenserna av dessa genom att jämka på tillståndet, dvs. att inte helt följa lagens bokstav. Anpassning till asymmetrisk information gör att myndigheten får tillgång till verksamhetsspecifik information. Anpassning till villkorsöverträdelser gör att nyttan med regleringar kan vägas mot kostnader för kontrollåtgärder. Villkorade tillstånd har även andra fördelar. Utvägen att neka ett tillstånd ger myndigheten en viss förhandlingsstyrka. Möjligheten att bestraffa verksamheten genom att dra in dess tillstånd medför att myndigheten kan spara kontrollresurser alternativt skärpa villkoren.