In the first chapter of this dissertation, I hypothesize that several non-tax-driven benefits of debt induce REITs managers to issue debt despite no apparent tax-driven benefit. Several methodologies and tests applied in capital structure literature are introduced to the literature of REITs capital structure. First, I investigate how the market prices leverage in absence of tax-deductibility benefit. Then, I diagnose the relative importance of several non-tax-driven benefits of leverage in deriving the capital structure decisions of REITs. Third, I conduct a thought investment experiment with debt-restricted vs. non-restricted REITs portfolios. I find weak evidence that leverage, by itself, creates value. Nevertheless, I find strong evidence that during financial crisis debt-restricted REITs perform better than non-restricted ones. Also I find evidence that lends support to the pecking order story of leverage. I conclude that REITs managers issue debt mainly to avoid issuing equity and to maximize wealth of existing shareholders. The second chapter addresses corporate diversification discount. I present and test a hypothesis that diversifiers exchange immediate diversification discount with future value gain attributed to unanticipated financial and strategic advantages of diversification. Two implications of this hypothesis are tested in this dissertation. First, the initial diversification discount found in static methodologies should be attenuated in a dynamic analysis. Second, diversifier's value evolution patterns are driven by the materialization of certain financial and strategic efficiencies. The overall results indicate that there is value recovery over time. Diversifiers' performance and value evolution is dynamically linked to synchronous improvements in market power, internal capital market activities, and cost efficiencies. Further, consistent with current evidence in diversification literature, related diversifiers outperform unrelated diversifiers. Moreover, related diversifiers witness faster value recovery relative to unrelated diversifiers.

Does efficient internal investment generally translate into successful external investment activities? In this research we use the internal capital allocation efficiency as a proxy for the efficiency of internal investment, and study whether firms that are internally efficient also make efficient external investment decisions. Our sample consists of multi-segment acquirers that announce acquisitions between 1986 and 2003 (only completed deals are included). We estimate short-term and long-term abnormal performance, excess value and operating performance around mergers in order to measure the success of acquisitions (external investment decisions). Our results indicate that internal capital allocation efficiency is indeed a significant factor in the success of acquisition. Firms that are internally efficient also make efficient external investment decisions. Conversely, internally inefficient firms are also externally inefficient. Thus, our results indicate that internal efficiency can be used as a predictor of the success and efficiency of external investment decisions.

This thesis considers the automatic acquisition of knowledge about discourse connectives. It focuses in particular on their semantic properties, and on the relationships that hold between them. There is a considerable body of theoretical and empirical work on discourse connectives. For example, Knott (1996) motivates a taxonomy of discourse connectives based on relationships between them, such as HYPONYMY and EXCLUSIVE, which are defined in terms of substitution tests. Such work requires either great theoretical insight or manual analysis of large quantities of data. As a result, to date no manual classification of English discourse connectives has achieved complete coverage. For example, Knott gives relationships between only about 18% of pairs obtained from a list of 350 discourse connectives. This thesis explores the possibility of classifying discourse connectives automatically, based on their distributions in texts. This thesis demonstrates that state-of-the-art techniques in lexical acquisition can successfully be applied to acquiring information about discourse connectives. Central to this thesis is the hypothesis that distributional similarity correlates positively with semantic similarity. Support for this hypothesis has previously been found for word classes such as nouns and verbs (Miller and Charles, 1991; Resnik and Diab, 2000, for example), but there has been little exploration of the degree to which it also holds for discourse connectives. We investigate the hypothesis through a number of machine learning experiments. These experiments all use unsupervised learning techniques, in the sense that they do not require any manually annotated data, although they do make use of an automatic parser. First, we show that a range of semantic properties of discourse connectives, such as polarity and veridicality (whether or not the semantics of a connective involves some underlying negation, and whether the connective implies the truth of its arguments, respectively), can be acquired automatically with a high degree of accuracy. Second, we consider the tasks of predicting the similarity and substitutability of pairs of discourse connectives. To assist in this, we introduce a novel information theoretic function based on variance that, in combination with distributional similarity, is useful for learning such relationships. Third, we attempt to automatically construct taxonomies of discourse connectives capturing substitutability relationships. We introduce a probability model of taxonomies, and show that this can improve accuracy on learning substitutability relationships. Finally, we develop an algorithm for automatically constructing or extending such taxonomies which uses beam search to help find the optimal taxonomy.

S ohledem na skutečnost, že více než polovina uskutečněných fúzí a akvizic je považována za neúspěšnou, realizovala jsem výzkum, který sleduje proces fúzí a akvizic v České republice a hodnotí jejich úspěšnost s ohledem na vývoj odvětví. Ve své disertační práci se zabývám vývojem fúzí a akvizic uskutečněných českými subjekty od roku 1997 až do 1. poloviny roku 2008 a hodnotím tento vývoj z několika hledisek tak, abych mohla posoudit úspěšnost transakčního procesu českých podnikatelských subjektů. Dospěla jsem k závěru, že akviziční společnosti mají před i po akvizici většinou velmi dobré finanční výsledky. Fúzované společnosti jsou naopak v době transakce pod průměrem České republiky, avšak v po transakčním vývoji se jejich finanční výsledky vyvíjejí ve srovnání s odvětvím velmi pozitivně. I když je potřeba zohlednit individuální charakter každé transakce, konstatuji, že v období 1997 až 2007 převažovaly v České republice úspěšné fúze a akvizice. Další závěry: - Transakční aktivita na území České republiky vykazuje klesající trend. - Nejčastěji probíhají fúze a akvizice mezi českými společnostmi navzájem. České společnosti nejčastěji kupují ze zahraničních subjektů slovenské společnosti. Naopak české společnosti jsou předmětem zájmu německých a amerických společností. - Některá průmyslová odvětví zaznamenávají klesající trend zájmu o transakce. - Hodnota transakce v období 1997 až 1. polovina roku 2008 v České republice klesá. - Nejčastějším způsobem úhrady kupovaného podílu je hotovost. - Nejčastěji se kupují společnosti, kde lze získat stoprocentní podíl nebo alespoň majoritu.

Knowledge sharing is of great importance for many of the companies today (Spender and Grant, 1996) and been a hot topic amongst researchers in the field of business and organization science (Alvesson and Karreman, 2001). Previous researches have been focusing on; the construction of good knowledge management systems, the general challenges of knowledge sharing including from a psychology perspective, increasing motivation to share knowledge etc. (Hahn and Subramani, 2000; Hung et. al, 2011). However, less research has been done on knowledge sharing between the organization and an acquired company specialized in a different area of knowledge (Gammelgaard et. al., 2004).  Hence, the objective of this thesis is to study the arising knowledge sharing challenges during an acquisition and whether reward system can be utilized to motivate the employees to overcome these challenges by encouraging them to engage in knowledge sharing activities.   In order to conduct this study, a case of a mid-sized consultant company with approximately 600 employees acquiring another smaller consultant company in a different field of knowledge with approximately 200 employees was used. Interviews were conducted with chosen people from both companies, amongst them were both CEOs and consultants. From the findings made from the interviews, the following conclusions were drawn. The identified challenges, which arose during the acquisition, were not dividing the company, communication, motivation and the use of terminology. In addition, although reward systems would increase employees’ motivation to engage in knowledge sharing activities, in the short-term, it should be avoided since it does not influence the long-term motivation. Intrinsic motivation was found to have the best long-term effect when coupled with the culture of the organization.

Masters Research - Fuculty of Health Sciences / Tuberculosis (TB) is one of the leading causes of mortality in the developing world. Mycobacterium tuberculosis, the causative organism, infects approximately a third of the world’s population. With high rates of HIV infection, particularly in sub-Saharan Africa, TB rates are inevitably soaring. Treatment regimens are based on multi-drug therapy taken over a prolo nged period, leading to poor patient compliance, in turn resulting in the development of multi-drug resistant TB (MDR-TB) which is difficult to treat. The need for new anti-TB drugs that can decrease the period of treatment or the number of doses and that will be effective against latent and MDR-TB is desperate. An added advantage would be the ability of a new class of anti-TB drugs to have a novel target to avoid potential crossresistance to existing drugs. Various approaches have been taken to antituberculosis drug development, including the high-throughput screening of plants, which represent an enormous, largely untapped resource of novel compounds. A further parameter to increase the chances of finding promising lead compounds is to focus research on plants that have traditionally been used to treat symptoms associated with TB. Traditional herbalists prescribing plant-based treatments have long played an important role in the provision of primary healthcare, especially in rural areas where most of the population is poor and unable to afford modern drugs. The aim of this study is to research literature resources pertaining to medicinal plants in southern Africa used to treat symptoms associated with TB, collect these plants, prepare methanol and acetone extracts for the antimicrobial and antimycobacterial testing, identify a plant with promising activity, and to isolate the active principle/s. These compounds in turn would be identified structurally and tested for activity against a range of micro-organisms, including mycobacteria, as well as for cytotoxicity. Twenty-three plant parts from nineteen different species were collected and 46 extracts prepared. These extracts were tested against a range of Gram-positive and –negative bacteria and fungi using the disc diffusion and broth micro-dilution methods. The effects of these extracts were also tested against non-pathogenic mycobacteria using the broth microdilution method, and against M. tuberculosis using the radiometric BACTEC 460 ABSTRACT V method. Te n of the nineteen species exhibited activity against two or more of the eleven organisms tested, namely Xerophyta retinervis bark, Helichrysum odoratissimum leaves, Ozoroa paniculosa bark, Eriocephalus africanus leaves, Siphonochilus aethiopicus roots, Conyza scabrida leaves, Syzigium cordatum bark, Tetradenia riparia leaves, Datura stramonium leaves and Dioscorea sylvatica tubers. The acetone extract of O. paniculosa was further pursued for the isolation of its active principles as it exhibited potent activity against Enterococcus faecalis, Pseudomonas aeruginosa, M. tuberculosis and Mycobacterium aurum with MIC’s of less than 1mg/ml. Previous work on related species has indicated anti-cancer, anti-helminthic, anti- malarial and anti-schistosomiasis activities, but no antimicrobial or antimycobacterial properties have been researched. Moronic, anacardic, and ginkgolic acids have previously been isolated from related species. Bio-assay guided fractionation led to the isolation of a known C15:1 anacardic acid (compound 1) and two HPLC fractions (HPLC2 and HPLC3) of which the predominant components of HPLC3 is the saturated analogue of anacardic acid. NMR data of HPLC2 suggest it is also a C15:1 anacardic acid, although the location of its double bond is as yet unkown. These compounds were cytotoxic to CHO cells at 44.9 – 64μg/ml. Compound 1 and HPLC2 were moderately active against M. tuberculosis with MIC’s of 125μg/ml, while HPLC3 had increased activity with an MIC of 31.3μg/ml, work not previously reported. Similarly, HPLC3 had the greatest activity a gainst M. smegmatis with an IC50 value of 22.1μg/ml. M. aurum had higher IC 50 values ranging from 98.4 to 112.5μg/ml for all three compounds. Compound 1 had potent activity against a range of Grampositive bacteria with IC50 values of 1.3, 2.1 and 6.5μg/ml against Bacillus cereus, E. faecalis and Staphylococcus aureus respectively. Furthermore, this compound had good activity against one of two drug-resistant strains of S. aureus tested with IC50’s of 6.9 and 43.2μg/ml. The saturated anacardic acid (HPLC3) in general had poorer activity against Gram-positives than its unsaturated analogues, consistent with reported literature. The anacardic acids had decreased activity against yeast and Gram-negative organisms tested, with IC50 values of around 80μg/ml against Candida albicans, 19 ->250μg/ml for Serratia odorifera, 26 - >250μg/ml for Klebsiella pneumoniae and 17 – 68μg/ml for ABSTRACT VI Pseudomonas aeruginosa, results comparable to those previously reported. The saturated anacardic acid appeared to have better activity than its unsaturated analogues against Gram- negatives and yeast. The current literature suggests that lipophilic compounds have greater activity against M. tuberculosis. Results obtained in this project are in support of these findings, as the saturated anacardic acid, believed to be the major constituent of HPLC3 based on NMR data available, had increased activity against this organism compared to the unsaturated and less hydrophobic compound 1 and HPLC2. It is possible that these findings implicate anacardic acid in the disruption of the mycobacterial cell wall.

Le besoin social de l'enfant de communiquer avec son entourage entraine une grammaticalisation progressive de son langage, qui passe notamment par l'acquisition des morphèmes grammaticaux libres. Plusieurs études mentionnent et analysent la présence de formes précurseures de ces éléments, souvent appelées fillers. A partir de corpus longitudinaux de quatre enfants en interaction avec un adulte, nous nous sommes intéressées au rôle de ces formes dans l'acquisition des articles et des clitiques sujets. L'utilisation du terme « formes de transition », et non de « fillers », nous a permis de décrire des formes produites par les enfants notamment à la fin de l'acquisition des articles et des clitiques sujets. Alors qu'une majorité des études sur les fillers se focalise sur le langage de l'enfant, notre objectif est de mettre en évidence le rôle fondamental de l'interaction entre l'enfant et l'adulte dans le processus d'appropriation des articles et des clitiques sujets. Une étude de l'évolution de la production de formes de transition nous a permis de décrire des tendances générales de développement chez les enfants observés, suivant un certain nombre de variations de l'émergence jusqu'à la maîtrise complète des articles et clitiques sujets. Une analyse de l'évolution des reprises chez l'enfant et l'adulte et du déroulement de leurs échanges nous a conduite au repérage de séquences d'interaction où l'adaptation des reprises de l'adulte aux tâtonnements de l'enfant entraine une progression dans les essais et les productions de ce dernier nous permettant d'illustrer le rôle d'une interaction immédiate adaptée dans le processus d'appropriation des articles et des clitiques sujets. / The social need of children to communicate with their minders and siblings results in a gradual grammaticalisation of their language, which includes the acquisition of free grammatical morphemes. Several studies mention and analyse the presence of proto-forms of these elements, often called fillers. On the basis of longitudinal corpora of four children interacting with an adult, I have studied the role of these forms in the acquisition of articles and subject clitics. The use of the phrase "transition forms" and not "fillers" enabled me to describe the forms produced by the children especially towards the end of the acquisition of articles and subject clitics. Whereas most studies concerning fillers concentrate on child language, my objective is to highlight the fundamental role of the interaction between child and adult in the acquisition of articles and subject clitics. A study of the evolution of the production of transition forms helped me describe general developmental trends among the children under observation, from a certain number of emergent variations to the complete mastery of articles and subject clitics. An analysis of the evolution of repetitions among the children and the adult and of the development of their exchanges helped me identify interactive sequences where the adaptation of the adult's repetitions to the children's attempts results in progress in the children's trials and utterances. This illustrates the role of immediate adjusted interaction in the acquisition of articles and subject clitics.

De par leur présence à l’interface entre plusieurs domaines linguistiques (phonologie, morpho-syntaxe, sémantique ou pragmatique), les déterminants ont depuis longtemps suscité l’intérêt des chercheurs en acquisition. On trouve ainsi de nombreux travaux portant notamment sur les contraintes phono-prosodiques, lexico-syntaxiques, sémantiques ou pragmatiques à l’œuvre dans le processus d’acquisition de ces formes, mais peu d’entre eux ont cherché à proposer une analyse combinée de ces facteurs, en tenant compte à la fois des morphèmes adultes et des formes de transition (omissions et fillers). Nous avons donc souhaité, dans le cadre de ce travail, décrire l’émergence des déterminants et de leurs proto-formes en essayant de saisir, dans une perspective multidimensionnelle intégrant à la fois des facteurs distributionnels et fonctionnels, quels facteurs influencent le plus ce processus, et à quelles périodes.Cette thèse repose sur l’analyse d’un corpus longitudinal de quatre enfants, âgés de 1;6 pour le plus jeune lors de la première séance sélectionnée à 3;5 pour le plus âgé lors de la dernière. Nous avons repéré au sein de ce corpus tous les noms produits par les enfants ainsi que les formes les précédant et chaque syntagme a fait l’objet d’une analyse phono-prosodique, lexico-syntaxique, sémantique, pragmatique et discursive.Les résultats montrent d’une part que tous les facteurs distributionnels peuvent - à des degrés différents - influencer la production des formes pré-nominales, et d’autre part, que les usages que les enfants font des formes témoignent d’une sensibilité précoce à certains contrastes pragmatico-discursifs. Toutefois, aucun des facteurs pris séparément n’a permis de rendre compte de l’intégralité des productions des enfants. L’analyse conjointe de ces facteurs distributionnels et fonctionnels a confirmé les tendances dégagées au préalable et a mis en évidence l’influence d’un ensemble de facteurs (et en particulier, phono-prosodique, syntaxique et pragmatique) plus que d’un facteur unique ou prédominant tout au long du processus d’acquisition des déterminants. / Given their presence at the crossroads of different linguistic fields (phonology, morphosyntax, semantics or pragmatics), determiners have for a long time aroused the interest of language acquisition researchers. We thus find several studies dealing with the phono-prosodic, lexical and syntactic, semantic or pragmatic constraints involved in the acquisition of determiners. But only few of them have provided a combined analysis of all these factors, considering both adult morphemes and transitional forms (omissions and filler syllables). Our study aims to describe the emergence of filler syllables and determiners and understand - in a multidimensional perspective examining simultaneously distributional and functional factors - which factors may affect the acquisition process, and over which periods of time.Our study is based on a corpus of four children, aged from 1;6 for the youngest in the first selected session to 3;5 for the eldest in the last session. We first identified all the noun phrases produced in the data and each occurrence was then analysed according to phono-prosodic, lexical, syntactic, semantic, pragmatic and discursive factors.Our results show that each distributional factor may influence, at different degrees, the production of pre-nominal forms and that children’s use of forms shows early sensitivity to pragmatic factors. However, none of the factors taken separately have accounted for all of the children’s productions. An additional combined analysis of both distributional and functional factors has supported the initial trends and highlighted the influence of a series of factors (and in particular, phono-prosodic, syntactic and pragmatic), more than a single and predominant one throughout the acquisition process of determiners.

University of Macau / Faculty of Arts and Humanities. / Department of Portuguese

University of Macau / Faculty of Arts and Humanities. / Department of Portuguese