Mergers and acquisitions play an important role in international financial markets, which explains why this research area attracts of lot of attention from academics, bankers, and investors. Generally, in takeovers, two firms merge in order to achieve specific strategic and business objectives. The ultimate goal is often, but not always, the creation of shareholder value. In many cases, the creation of shareholder value is not the primary objective of the managers, however, which is one of the reasons why takeovers have been associated with the destruction of value in several existing studies. Instead, many M&A decisions are a function of managerial behaviour. In this thesis, I investigate the drivers of M&A activity, and consider both purely rational (neo-classical) and behavioural reasons as managers’ motivations for getting involved in M&A transactions. The thesis’s main body consists of three empirical studies that investigate how M&A activity is driven by macro-economic forces, managerial behaviour and board networks. Chapter 3 investigates whether merger waves are driven by macro-economic determinants and financial markets; Chapter 4 tests whether envy among CEOs has any explanatory power over the appearance of merger waves; Chapter 5 looks at whether board networks affect the relative merits of acquisitions and the probability of acquiring firms in “linked” industries. More specifically, Chapter 3 tests the extent to which US and UK merger waves are driven by macro-economic and financial market factors. Besides the analysis of domestic M&A activity, I also study the drivers of cross-border acquisitions between the UK and the US. I disentangle M&A activities according to how they are financed, and test whether managers follow market timing strategies when engaging in M&A transactions. I find evidence that domestic takeovers in the US and in the UK are highly correlated with the credit cycle and moderately correlated with the business cycle. I also test wave patterns in US and UK merger waves, and find that the merger waves in the two countries are significantly related to each other. Chapter 4 considers the view that irrational managerial behaviour could trigger UK merger waves. In particular, I assume that CEOs assess their own situation relative to those of their peers. If a CEO earns less than his peers, he becomes envious. Since it is established in the literature that firm size and executive compensation are positively correlated, CEOs have an incentive to engage in size-increasing mergers in order to decrease any compensation differential. Cross-sectional envy should therefore be considered as a potential explanation for merger waves. In an interdisciplinary approach, I develop a new measure for envy that is based on theories borrowed from the sociology area. My results from comprehensive tests with this new measure show that envy is unlikely to be an explanation for UK merger waves. Chapter 5 uses social networking theory to examine possible benefits for the acquirer from being well-connected. I assume that strong board networks are associated with better and faster access to information. Building on this rationale, I hypothesize that well-connected acquirers make better acquisitions due to reduced information asymmetries between them and the target. This chapter examines whether board interlocks between the acquirer and the target, existing prior to the acquisition, are associated with superior cumulative abnormal returns for the acquirer. Using centrality measures from social networking theory, I test whether firms that are well-connected make better acquisitions, as measured by the announcement returns of the acquirer. I find acquirer-target board interlocks to be significantly and positively associated with the acquirer’s cumulative abnormal returns. Centrality measures, however, turn out not to have any significant impact on the acquirer’s stock price reaction. Lastly, I show that acquirers are significantly more likely to acquire firms from industries with which they are “linked” via board members that have multiple directorships.

This thesis aims at contributing to the existing studies in the dynamic stochastic general equilibrium model, particularly in the new Keynesian models, on three aspects. It consists of three chapters. Chapter 2 is on “Dynamic new Keynesian Life-Cycle Model.” Chapter 3 is on “Re-thinking Price Stability in an Economy with Endogenous Firm Entry: Real Imperfections under Product Variety.” Chapter 4 is on “Growth Expectation.” Abstracts of each Chapter are as follows. In Chapter 2, we first construct a dynamic new Keynesian model that incorporates life-cycle behavior a la Gertler (1999), in order to study whether structural shocks to the economy have asymmetric effects on heterogeneous agents, namely workers and retirees. We also examine whether considerations of life-cycle and demographic structure alter the dynamic properties of the monetary business cycle model, specifically the degree of amplification in impulse responses. According to our simulation results, shocks indeed have asymmetric impacts on different households and the demographic structure does alter the size of responses against shocks by changing the trade-off between substitution and income effects. In Chapter 3, we re-think price stability in an economy with endogenous firm entry under possible distortions. We first demonstrate that endogenous entry causes real imperfections. Reflecting fluctuations in the number of varieties, the gap between the natural and the efficient level of output is no longer constant and variant to shocks. As a result, the central bank faces a trade-off between stabilizing inflation and welfare-relevant output gap. Then, we show that this results in the non-zero optimal rate of inflation. We further check whether welfare can be enhanced by targeting welfare-based inflation instead of cross-sectional average inflation contrary to the previous findings. Simulations even with such distortions as unknown natural interest rate or no fiscal remedy for efficient non-stochastic steady states, however, support cross-sectional average inflation targeting although there may exist some small gains by referring also to welfare-based inflation rates. Incomplete stabilization may enhance welfare in an economy when agents cannot internalize the externality on the love for variety. Chapter 4 is about the difficulty in producing reasonable business cycles for the expectation shock about higher future technology. For a long time, changes in expectations about the future have been thought to be significant sources of economic fluctuations, as argued by Pigou (1926). Although creating such an expectation-driven cycle (the Pigou cycle) in equilibrium business cycle models was considered to be a difficult challenge, as pointed out by Barro and King (1984), recently, several researchers have succeeded in producing the Pigou cycle by balancing the tension between the wealth effect and the substitution effect stemming from the higher expected future productivity. Seminal research by Christiano et al. (2007a) explains the “stock market boom-bust cycles,” characterized by increases in consumption, labor inputs, investment and the stock prices relating to high expected future technology levels, by introducing investment growth adjustment costs, habit formation in consumption, sticky prices and an inflation-targeting central bank. We, however, show that such a cycle is difficult to generate based on “growth expectation,” which reflect expectations of higher productivity growth rates. Thus, Barro and King’s (1984) prediction still applies.

Why and under what conditions do governments borrow before elections? This thesis aims to shed light on this question by exploring governments' incentives that give rise to political budget cycles, i.e. fluctuations in the budget balance during election times, under different political, institutional, and economic contexts. The argument will be developed in three stages. First, the thesis will explain why politicians may choose to use debt strategically to win elections and discuss and evaluate different models that can explain political budget cycles. One model, a moral hazard type competence model is, as will be shown, particularly suited for this study. It will be extended in stages two and three. The second stage will look at the benefits and costs from public debt, with a particular emphasis on the likelihood of re-election (government popularity), party system polarisation, and sovereign risk. Sovereign risk increases the cost of borrowing and thus dampens the magnitude of political budget cycles; the effect of government popularity on strategic debt is conditional on the degree of polarisation. The third stage will take the motives to borrow as given and examine the effectiveness of debt as a strategic instrument. The less voters attribute responsibility for fiscal policy to governments, the less effective debt is as a strategic instrument. Economic volatility, regulatory density, and economic openness, this thesis argues, reduce this effectiveness and in turn the political budget cycle. Similarly, coalition government reduces responsibility associated with individual coalition partners, and thus the strategic value of public debt - yet this effect is moderated by the distribution of cabinet portfolios. The argument in this thesis is based both on formal models and on empirical, time series-cross sectional, analyses. It is arguably the most comprehensive treatment of political budget cycles and adds to an increasing literature on the contextual determinants of fiscal policy.

This thesis studies the optimal conduct of unconventional monetary policy in the form of purchases of long-term government debt by the central bank and, motivated by this policy tool, the evolution of long-term government debt holdings in household portfolios over the course of the life cycle. It is comprised of three self-contained chapters. The first chapter investigates whether it can be beneficial for central banks to use the unconventional tool even when the main policy rate is not constrained by the zero lower bound. A friction in the interaction between households and banks allows central bank purchases of long-term government debt to reduce long-term interest rates and thus to stimulate economic activity. If debt purchases and conventional short-term interest rate policy are coordinated in an appropriate way, the central bank is able to reduce the volatility of output and inflation. In the second chapter, the role that unconventional monetary policy can play in a currency union is analysed. A model is laid out, in which two countries form a currency union with a common central bank but separate and uncoordinated fiscal policy institutions. When monetary policy is implemented only through the common short-term interest rate, the central bank is unable to respond effectively to country-specific shocks. Due to segmentation in the market for long-term government debt, the yield on long-term debt can differ across countries. As a result, a monetary policy authority that can rely on bond purchases is able to address idiosyncratic shocks reflected in volatility of the natural terms of trade more effectively and to achieve higher welfare than one that cannot make use of this instrument. The final chapter studies the long-term government bond share in household portfolios over the course of the life cycle. US data from the Survey of Consumer Finances suggests that participation in the market for long-term government debt first increases and later decreases as agents approach the retirement age. The portfolio share conditional on participation is non-decreasing over the working life. These stylised facts can be explained by means of a portfolio choice model in which agents are subject to aggregate risk through asset returns as well as idiosyncratic risk through labour income and the stochastic events of retirement and death.

This thesis is divided into two main parts. The first provides a novel analysis of dynamic optimal taxation under the assumption that individuals in an economy have ‘hidden’ idiosyncratic productivity levels. Specifically, it shows how to derive a complete set of optimality conditions characterising the solution to a problem of this kind. The method relies on constructing perturbations to the consumption-output allocations of agents in a manner that preserves all relevant incentive compatibility restrictions. We are able to use it to generalise the ‘inverse Euler condition’ to cases in which preferences are non-separable between consumption and labour supply, and to prove a number of novel results about optimal income and savings tax wedges. The second main part investigates a more general problem. When policymakers are constrained in their present choices by expectations of future outcomes a well-known time-inconsistency problem hinders optimal decision-making: the preferences of policymakers who exist at different points in time are not in agreement with one another, because of differences in the constraints faced by each. We present a new approach to determining policy in this setting, based on asking: What policy would be chosen by a decisionmaker who did not know the time period in which their choice was to be implemented? This is akin to designing institutions from behind a Rawlsian ‘veil of ignorance’. The theory is used to obtain qualitative policy prescriptions across a number of environments; these policies have several appealing properties that we outline.

Community engagement initiatives have experienced an increase in attention, appreciation, and participation among those in academic, nonprofit, and other community-based organizations over the past two decades. The purpose of this study is to explore the meanings of community-campus partnerships among stakeholders in the community and in academia towards the goal of generating a theory grounded in these data that will concomitantly contribute to the social work profession and the community engagement movement. Using as its foundation the shared interest among the social work profession and the community engagement movement on values and ethics, this study utilizes a traditional grounded theory methodology as a means to systematically examine the question “What does it mean to be involved in a community-campus partnership?” The theory that emerged from the data in this study is about what it takes to sustain partnerships between community and campus organizations. The final five themes found in this theory are: A strong foundation upon which the relationship is built; navigating the process of a partnership project; goodness-of-fit for all involved; resources; and impact. Overall, the theory of partnership sustainability draws the attention of partnership practitioners and stakeholders to the importance of relationships as being the core for any partnership activity. When contemplating how a particular resource, impact, process-related challenge and issue of partner match was addressed within their partnership, the participants continually came back to the idea that partnership sustainability can be traced back to the relationship between partners. Implications for further research involve a deeper study of the nature of relationships within community-campus partnerships; the organizational culture dynamics that are unique to academia; the nature, value, and perceived importance of research done in the community; and the intersectionality of student engagement and community engagement, particularly in an age of assessment and benchmarking.

In this collection of essays, I explore three topics where space and distance plays a fundamental role in international economics. Not only do spatial considerations affect the pattern of trade, the frictions that arise from distance also determine where and how goods are produced and where people live. In Chapter 1, I show that human made locational characteristics can determine the spatial allocation of economic activity. I take the standard core-periphery model and add endogenous housing to its forward-looking dynamic adjustment process. By introducing a model of adjustment with an extra state variable, which I interpret as housing, I show that the distribution of housing allows the model to converge to a unique spatial equilibrium. This explains the observed persistence and robustness of economic agglomerations in the data. Chapter 2 is a theory of task assignment in the production of final goods and across countries. By allowing for tasks to differ in their suitability of being used in the production of multiple goods, my model endogenizes the allocation of tasks in the production of goods that use them. The resulting equilibrium task allocation defines the pattern of off-shoring. Tasks that are used in only one good concentrate in the country with a specialization in production of that good. Tasks used in many goods are allocated across countries, with the more substitutable tasks located in the country with the larger overall output. Gains from off-shoring are derived from a better mix of allocation of tasks into goods as well as larger scale of production. Finally in Chapter 3, I study how real exchange rate fluctuations determine the size and composition of the export sector. Using the methodology set out in Dixit and Pindyck (1994) in a heterogeneous firms model, I determine the set of trigger real exchange rates for entry and exit into exporting. My primary result of this chapter is that exchange rate uncertainty coupled with sunk cost of entry causes hysteresis in the number and productivity of exporting firms. I then extend the model to allow free entry of firms. This explains the stylized fact of the existence of non-exporting firms with higher productivity than some exporting firms.

Compte tenu des attentes en termes de développements durables, de nouvelles solutions technologiques sont adoptées dans les bâtiments à basse consommation énergétique permettant de réduire considérablement les déperditions par ponts thermiques. Il s’agit des rupteurs thermiques, nouvelles jonctions entre porteurs verticaux et horizontaux constituées de matériaux innovants. Parallèlement à l’évolution des réglementations thermiques dans les bâtiments, la nouvelle définition de l’aléa sismique en France oblige les concepteurs à intégrer le cas de chargement sismique dans les dimensionnements de bâtiments dans une grande majorité du territoire métropolitain. Ces innovations technologiques nécessitent donc des études approfondies de leur comportement mécanique lors d’événements accidentels tels que les tremblements de terre. Au regard des enjeux sociétaux et économiques, il est d’une grande importance d’être capable d’apprécier la contribution de nouvelles solutions techniques à la vulnérabilité du bâti aux séismes. Pour cela, il est nécessaire de procéder à des analyses probabilistes pour la construction, par exemple de courbes de fragilité de structures sous sollicitations sismiques: structures étant composées ou non de rupteurs thermiques. L’objectif de ce travail est donc de proposer l’ensemble d’une méthodologie notamment les outils numériques, en termes de modèles mécaniques, susceptibles de répondre aux attentes de l’ingénierie dans la quantification de l’évolution des marges de résistance en intégrant différents types de rupteurs thermiques dans les bâtiments. Pour cela, différentes étapes, combinant modélisations numériques et expérimentations sont abordées afin d’élaborer un modèle numérique simplifié. Ce dernier doit être riche en termes de phénomènes mécaniques et efficace numériquement pour réaliser rapidement un nombre important de calculs nonlinéaires à l’échelle de bâtiment en tenant compte des aspects aléatoires. / Nowadays sustainable constructions imply an objective of energetic performances by reducing the level of thermal conduction. The thermal-break elements, an innovative technological element is under study in several countries in Europe. If the thermal benefits have already been proved, the mechanical effects of such a wall-slab connection in a building for the seismic risk have not been assessed. To evaluate the building seismic vulnerability modifications due to these thermal breaks, experimental and numerical developments have to be performed. An experimental campaign is proposed to evaluate the seismic ability of such structural elements and a simplified modelling is proposed aiming at developing numerical framework able to handle parametrical and probabilistic approaches for structural analysis. This model is also validated in dynamic case by using the Pseudodynamic testing.

Une modélisation récente, qualifiée de multiphasique, permettant de décrire le comportement des ouvrages en sols renforcés par inclusions a été développée et intégrée dans un code de calcul par éléments finis. Le champ d'application de cette approche a été étendu pour rendre compte du comportement macroscopique de matériaux à fibres tels que le plâtre, le béton de fibres, les ouvrages en sol renforcés par des fibres et les tissus osseux qui présentent une microstructure constituée d'une matrice et d'une distribution de fibres plus ou moins longues orientées dans toutes les directions de l'espace. Cette approche est d'abord mise en œuvre pour déterminer le comportement élastique du composite à fibre, les résultats obtenus sont comparés à ceux fournis par les schémas d'estimation dilué et de Mori Tanaka, basés sur la solution d'Eshelby, la suite de ce travail est consacrée au développement du modèle dans le cadre d'un comportement anélastique des constituants. Des solutions analytiques ont été développées permettant de retrouver le comportement macroscopique des matériaux à fibres sous certaines sollicitations simples dans le cadre d'un comportement élasto-plastique ou élastique-fragile des différents constituants. Le modèle est par la suite mis en œuvre numériquement dans le cadre de la méthode des éléments finis permettant d'accéder à la réponse de structures en matériaux à fibres / A multiphase model has been recently developed and integrated into a finite element based code for the analysis and design of soil structures reinforced with linear inclusions. This approach is extended to account for the macroscopic behavior of fiber reinforced materials such as plaster, concrete fiber, soil reinforced by short fibers and bone tissues, which are constituted of a matrix and a distribution of continuously oriented fibers. The proposed model is performed to evaluate the elastic macroscopic stiffness of the composite material, the obtained results are compared to those deriving from the dilute and Mori-Tanaka estimations. The model is then extended to take into account a nonelastic behavior of the constituents. Starting from the derivation of some analytical solutions to boundary value problems involving fiber reinforced materials in the context of elasto-plastic and brittle behavior of the matrix and fibers, a f.e.m.-based code is developed and applied to simulating the behavior of some typical structures

Dans ce travail, l'oxydation totale du toluène et de la butanone sur des catalyseurs à base d'or et de palladium supportés sur un oxyde de titane macro-mésoporeux a été étudiée. Nous avons tout d'abord discuté l'effet bénéfique du dopage (V, Nb, Fe, Ce, Ni) du support TiO₂ macro-mésoporeux sur l'activité catalytique de ce matériau. Une interaction existant entre le dopant et le support a joué un rôle important dans l'augmentation de l'activité des matériaux dopés par rapport à celle du titane pure. Une phase active constituée d'or et/ou de palladium a été ensuite déposée sur les solides dopés et la performance des catalyseurs préparés a été suivie dans l'oxydation du toluène et de la butanone. La présence de la phase active a assuré une sélectivité totale pour le CO₂ avec la formation de sous-produits en particulier dans l'oxydation de la butanone. Par ailleurs, l'oxydation du mélange des deux COVs a montré l'existence d'une compétition entre les molécules en terme d'adsorption sur le support, ce qui a favorisé leur éliminationà de basses températures. Une étude operando DRIFT réalisée dans l'oxydation du mélange toluène/butanone a vérifié la présence de cette compétition. / In this work, the total oxidation of toluene and butanone over noble metal loaded doped titanium oxide supports has been investigated. The study focused firstly on showing the effect of doping a macro-mesoporous titania with metal oxide supports in the oxidation of VOCs. It seems that doping enhances the performance of the used solid in VOC oxidation reactions. We proved that this increase can be directly related to interactions between the dopants and the support. Then, an active phase made of noble metals has been loaded onto both best performing doped materials as to study the role played by this active phase in oxidation reactions. It appears that the presence of noble metals increases the catalytic performance of prepared materials and reduces the formation of toxic by-products such as CO. Butanone elimination proved to be harder that toluene oxidation, whereas when catalysts were exposed to a mixture of toluene and butanone, the presence of both VOCs prompted a competitive effect in the adsorption of both molecules onto the support, which facilitated their oxidation rate. An FTIR operando study illustrated the changes occuring in used catalysts in the oxidation of the VOC mixture, and verified the existence of this competitive effect.