Optimization of time and cost in construction projects has been subject to extensive research since the development of the Critical Path Method (CPM). Many researchers have investigated various versions of the well-known Time-Cost Trade-off (TCT) problem including linear, convex, concave, and also the discrete (DTCT) version. Traditional methods in the literature for optimizing time and cost of construction projects range from mathematical methods to evolutionary-based ones, such as genetic algorithms, particle swarm, ant-colony, and leap frog optimization. However, none of the existing research studies has dealt with the optimization of large-scale projects in which any small saving would be significant. Traditional approaches have all been applied to projects of less than 100 activities which are far less than what exists in real-world construction projects. The objective of this study is to utilize recent developments in computation technology and novel optimization techniques such as Constraint Programming (CP) to improve the current limitations in solving large-scale DTCT problems. Throughout the first part of this research, an Excel-based TCT model has been developed to investigate the performance of traditional optimization methods, such as mathematical programming and genetic algorithms, for solving large TCT problems. The result of several experimentations confirms the inefficiency of traditional methods for optimizing large TCT problems. Subsequently, a TCT model has been developed using Optimization Programming Language (OPL) to implement the Constraint Programming (CP) technique. CP Optimizer of IBM ILOG Optimization Studio has been used to solve the model and to successfully optimize several projects ranging from a small project of 18 activities to very large projects consisting of more than 10,000 activities. Constraint programming proved to be very efficient in solving large-scale TCT problems, generating substantially better results in terms of solution quality and processing speed. While traditional optimization methods have been used to optimize projects consisting of less than one hundred activities, constraint programming demonstrated its capability of solving TCT problems comprising of thousands of activities. As such, the developed model represents a significant improvement in optimization of time and cost of large-scale construction projects and can greatly enhance the level of planning and control in such projects.

Objective: The primary aim of this study was to assess patients’ preferences between radiofrequency ablation (RFA) versus hepatic resection (HR) for the treatment of small hepatocellular carcinomas (HCC). Methods: Decision analysis was performed by using probability trade-off (PTO) technique to elicit patients’ preferences and the strength of their decisions. Results: The vast majority of the study population preferred RFA over HR (70% vs. 30%, p=0.001). Their initial choice changed if 5-year survival benefit after surgery was at least 14% superior to RFA and if the 3-year disease-free survival advantage was at least 13% better than ablation. Conclusions: The results of this study suggest that fully informed cirrhotic patients would prefer RFA if diagnosed with early stage HCC even if able to undergo surgery.

As empresas alocam seus recursos escassos entre dois processos fundamentais: de criação de valor (ex. inovando, produzindo e entregando produtos ao mercado) e de apropriação de valor (ex. extraindo lucros do mercado). Embora ambos os processos sejam pré-requisito para a vantagem competitiva sustentável, a empresa possui considerável liberdade para decidir qual processo será enfatizado. Configura-se um trade-off estratégico que é representado por uma ênfase estratégica, ou seja, a ênfase relativa que a empresa emprega na apropriação de valor em relação à criação de valor. No entanto, poucas pesquisas exploraram o impacto desse trade-off no desempenho financeiro. Quais são os impactos da mudança da ênfase estratégica (criação de valor versus apropriação de valor) no desempenho financeiro das empresas no contexto brasileiro? Uma métrica de ênfase estratégica baseada nos gastos em P&D (criação de valor) e nos gastos de Marketing (apropriação de valor) foi testada e validada no contexto brasileiro. Em seguida, analisou-se o impacto financeiro deste trade-off por meio de cinco indicadores de desempenho (Retorno da Ação, Giro do Ativo, Margem Líquida, q de Tobin e Crescimento de Vendas) por meio de regressões múltiplas. Adicionalmente o trade-off foi investigado segundo três fatores: o ambiente tecnológico, a rentabilidade prévia e a estratégia do passado. A ênfase estratégica foi validada como indicador que mensura o trade-off entre criação de valor (exploration) e apropriação de valor (exploitation) no contexto brasileiro. Quando a empresa enfatiza mais a apropriação de valor relativamente à criação de valor, maior é o Giro do Ativo e o Crescimento das Vendas. Esses resultados podem ser fruto da administração míope de marketing, ou seja, a ênfase excessiva nos resultados de curto prazo por meio da redução dos investimentos em marketing. Isso não minimiza a relevância do processo de criação de valor, mas evidencia a importância dos mecanismos de isolamento na apropriação de parte do valor criado. Duas características da empresa se revelaram como moderadoras da relação entre a ênfase estratégica e o desempenho financeiro: a estratégia passada e a rentabilidade anterior. A estratégia anterior influencia a ênfase estratégica por meio dos retornos marginais decrescentes. As empresas que mudam sua ênfase estratégica anterior, seja criação de valor ou apropriação de valor, tendem a apresentar retornos superiores (maiores Margem Líquida, Giro do Ativo, Crescimento de Vendas e q de Tobin). Também se identificou que a rentabilidade anterior influencia a estratégia atual da empresa. Se a empresa foi lucrativa, a apropriação de valor é mantida para garantir uma Margem Líquida e um q de Tobin maiores. Por outro lado, as empresas com prejuízo se voltam à criação de valor para fomentar novas oportunidades de ganhos. Por fim, apresentam-se as limitações do estudo com a agenda de pesquisas futuras. / Firms allocate their limited resources between two fundamental processes of creating value (i.e., innovating, producing, and delivering products to the market) and appropriating value (i.e., extracting profits in the marketplace). Although both value creation and value appropriation are required for achieving sustained competitive advantage, a firm has significant latitude in deciding the extent to which it emphasizes one process over the other. There is a strategic trade-off represented by the strategic emphasis: the relative emphasis a firm places on value appropriation relative to value creation. However, few researches have explored the financial impact of this trade-off. What impact does strategic emphasis shift (i.e., emphasis on value creation versus value appropriation) have on firm‟s financial performance in the Brazilian context? A strategic emphasis metric based on the R&D spending (value creation) and on marketing spending (value appropriation) was tested and validated in the Brazilian context. Then, the financial impact of this trade-off was analyzed by five performance metrics (Stock Return, Asset Turnover, Net Margin, Tobin‟s Q and Sales Growth) by multiple regressions. In addition, the trade-off was investigated according three factors: technological environment, previous profitability and past strategy. The strategic emphasis was validated as a metric that measures the trade-off among value creation (exploration) and value appropriation (exploitation) in the Brazilian context. When the firm emphasizes more in value appropriation than the value creation, the Asset Turnover and the Sales Growth are higher. These results may occur because of the myopic marketing management, in other words, an overemphasis on the current term financial performance and the use of marketing tools to inflate current profitability measures. This doesn‟t understate the relevance of the value creation process, but rather highlight the importance of the isolating mechanisms in the appropriation of the part of the value created. Two firm‟s characteristics moderate the relation of strategic emphasis and financial performance: the past strategy and the previous profitability. The past strategy affects the strategic emphasis by the diminishing marginal returns. Firms that change their strategic emphasis (value creation or value appropriation), tend to present superior return (higher Net Margin, Asset Turnover, Sales Growth and Tobin‟s Q). Also the previous profitability influences the current firm‟s strategy. If the firm was profitable, the value appropriation is maintained to guarantee higher Net Margin and Tobin‟s Q. On the other hand, the firms with negative profitability turn to value creation to promote new opportunities of gains. Finally, research limitations and future research agenda is presented.

Human movements are remarkably adaptive, such that we are capable of completing movements in a novel environment with similar accuracy to those performed in a typical environment. Our ability to perform in these environments involves accurate processing of sensory feedback for online and offline control. These processes of control have been widely studied for well learned actions, but not for actions in a novel visuomotor environment. In two experiments, we examined control processes underlying reaches when participants were first introduced to a visuomotor rotation (Experiment 1) and then following visuomotor adaptation (Experiment 2). All participants completed 150 reach training trials when (1) a cursor accurately represented their hand motion (i.e., aligned cursor) and (2) a cursor was rotated 45 degrees clockwise relative to their hand motion (i.e., rotated cursor). In Experiment 1, we sought to determine if the control processes underlying movements in typical and novel visuomotor conditions were comparable. Participants (n = 16) received either continuous visual feedback or terminal visual feedback regarding movement endpoint during reach training. Analyses revealed that participants were able to demonstrate similar outcomes (i.e., movement time and endpoint errors) regardless of visual or cursor feedback, but also demonstrated more offline control (i.e., took more time planning and were less consistent in initiating their movements) when reaching with a rotated cursor compared to an aligned cursor, even at the end of training. Together, the results suggest a greater contribution of offline control processes and less effective online corrective processes when reaching in a novel environment compared to when reaching in a typical environment. In attempt to promote online corrective processes, participants (n = 16) in Experiment 2 first completed the training trials with continuous visual feedback and then completed an additional 45 reaches under (1) slow movement time (i.e., Slow MT: 800-1000 ms) and (2) fast movement time (i.e., Fast MT: 400-500ms) constraints. Results showed a shift to online control (i.e., greater endpoint accuracy) when reaching with an aligned and rotated cursor, when sufficiently more time was provided (i.e., Slow MT). Specifically, participants were able to more effectively utilize visual feedback for online control under the Slow MT constraint compared to when reaching quickly (i.e., Fast MT). Together, these experiments demonstrate a flexibility in control processes underlying reaches with rotated visual feedback of the hand. In that reaches first engage in offline control processes during adaptation to a visuomotor rotation, and then shift to online corrective processes following visuomotor adaptation.

As empresas alocam seus recursos escassos entre dois processos fundamentais: de criação de valor (ex. inovando, produzindo e entregando produtos ao mercado) e de apropriação de valor (ex. extraindo lucros do mercado). Embora ambos os processos sejam pré-requisito para a vantagem competitiva sustentável, a empresa possui considerável liberdade para decidir qual processo será enfatizado. Configura-se um trade-off estratégico que é representado por uma ênfase estratégica, ou seja, a ênfase relativa que a empresa emprega na apropriação de valor em relação à criação de valor. No entanto, poucas pesquisas exploraram o impacto desse trade-off no desempenho financeiro. Quais são os impactos da mudança da ênfase estratégica (criação de valor versus apropriação de valor) no desempenho financeiro das empresas no contexto brasileiro? Uma métrica de ênfase estratégica baseada nos gastos em P&D (criação de valor) e nos gastos de Marketing (apropriação de valor) foi testada e validada no contexto brasileiro. Em seguida, analisou-se o impacto financeiro deste trade-off por meio de cinco indicadores de desempenho (Retorno da Ação, Giro do Ativo, Margem Líquida, q de Tobin e Crescimento de Vendas) por meio de regressões múltiplas. Adicionalmente o trade-off foi investigado segundo três fatores: o ambiente tecnológico, a rentabilidade prévia e a estratégia do passado. A ênfase estratégica foi validada como indicador que mensura o trade-off entre criação de valor (exploration) e apropriação de valor (exploitation) no contexto brasileiro. Quando a empresa enfatiza mais a apropriação de valor relativamente à criação de valor, maior é o Giro do Ativo e o Crescimento das Vendas. Esses resultados podem ser fruto da administração míope de marketing, ou seja, a ênfase excessiva nos resultados de curto prazo por meio da redução dos investimentos em marketing. Isso não minimiza a relevância do processo de criação de valor, mas evidencia a importância dos mecanismos de isolamento na apropriação de parte do valor criado. Duas características da empresa se revelaram como moderadoras da relação entre a ênfase estratégica e o desempenho financeiro: a estratégia passada e a rentabilidade anterior. A estratégia anterior influencia a ênfase estratégica por meio dos retornos marginais decrescentes. As empresas que mudam sua ênfase estratégica anterior, seja criação de valor ou apropriação de valor, tendem a apresentar retornos superiores (maiores Margem Líquida, Giro do Ativo, Crescimento de Vendas e q de Tobin). Também se identificou que a rentabilidade anterior influencia a estratégia atual da empresa. Se a empresa foi lucrativa, a apropriação de valor é mantida para garantir uma Margem Líquida e um q de Tobin maiores. Por outro lado, as empresas com prejuízo se voltam à criação de valor para fomentar novas oportunidades de ganhos. Por fim, apresentam-se as limitações do estudo com a agenda de pesquisas futuras. / Firms allocate their limited resources between two fundamental processes of creating value (i.e., innovating, producing, and delivering products to the market) and appropriating value (i.e., extracting profits in the marketplace). Although both value creation and value appropriation are required for achieving sustained competitive advantage, a firm has significant latitude in deciding the extent to which it emphasizes one process over the other. There is a strategic trade-off represented by the strategic emphasis: the relative emphasis a firm places on value appropriation relative to value creation. However, few researches have explored the financial impact of this trade-off. What impact does strategic emphasis shift (i.e., emphasis on value creation versus value appropriation) have on firm‟s financial performance in the Brazilian context? A strategic emphasis metric based on the R&D spending (value creation) and on marketing spending (value appropriation) was tested and validated in the Brazilian context. Then, the financial impact of this trade-off was analyzed by five performance metrics (Stock Return, Asset Turnover, Net Margin, Tobin‟s Q and Sales Growth) by multiple regressions. In addition, the trade-off was investigated according three factors: technological environment, previous profitability and past strategy. The strategic emphasis was validated as a metric that measures the trade-off among value creation (exploration) and value appropriation (exploitation) in the Brazilian context. When the firm emphasizes more in value appropriation than the value creation, the Asset Turnover and the Sales Growth are higher. These results may occur because of the myopic marketing management, in other words, an overemphasis on the current term financial performance and the use of marketing tools to inflate current profitability measures. This doesn‟t understate the relevance of the value creation process, but rather highlight the importance of the isolating mechanisms in the appropriation of the part of the value created. Two firm‟s characteristics moderate the relation of strategic emphasis and financial performance: the past strategy and the previous profitability. The past strategy affects the strategic emphasis by the diminishing marginal returns. Firms that change their strategic emphasis (value creation or value appropriation), tend to present superior return (higher Net Margin, Asset Turnover, Sales Growth and Tobin‟s Q). Also the previous profitability influences the current firm‟s strategy. If the firm was profitable, the value appropriation is maintained to guarantee higher Net Margin and Tobin‟s Q. On the other hand, the firms with negative profitability turn to value creation to promote new opportunities of gains. Finally, research limitations and future research agenda is presented.

Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2017-07-20T12:22:41Z No. of bitstreams: 1 texto completo.PDF: 396848 bytes, checksum: ee1c80dd6220200e5ed4f623b97dd7b1 (MD5) / Made available in DSpace on 2017-07-20T12:22:41Z (GMT). No. of bitstreams: 1 texto completo.PDF: 396848 bytes, checksum: ee1c80dd6220200e5ed4f623b97dd7b1 (MD5) Previous issue date: 2002-02-28 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Percevejos predadores são inimigos naturais importantes de muitas espécies de artrópodos e em condição de campo estão constantemente expostos a xenobióticos usados para o controle de insetos-praga. Em várias classes de organismos, os efeitos de xenobióticos sobre variáveis biológicas são complexos e o entendimento dos mesmos são de grande importância para vários campos do conhecimento científico. Assim, estudou-se o efeito das doses subletais de 0,131; 1,315; 13,15; 131,5 e 1315 ppb de permetrina nos parâmetros biológicos de Podisus distinctus (Stål) (Heteroptera: Pentatomidae), aplicadas topicamente em ninfas de terceiro estádio desse predador. Houve redução na duração dos terceiro e quarto estádios nas doses de 0,131 e 1,315 ppb de permetrina, respectivamente. Evidenciou-se o efeito hormético com 0,131, 1,315 e 13,15 ppb de permetrina sobre ninfas de P. distinctus, as quais apresentaram maior peso e sobrevivência, além de menor duração ninfal nessas doses. Além disso, observou-se hormese em parâmetros reprodutivos, como os números de ovos e de ninfas/fêmea de P. distinctus. Tabelas de vida de fertilidade e de esperança de vida mostraram maiores valores da taxa bruta (TBR) e líquida (R 0 ) de reprodução na dose de 0,131 ppb de permetrina que no controle e demais doses. O aumento populacional desse predador por ano foi maior com essa dose de permetrina, o que confirma também, a ocorrência de hormese. A hormese, embora raramente observada em inimigos naturais em condições de campo, pode ser induzida e melhorar a performance reprodutiva de P. distinctus e representa uma ferramenta para programas de controle biológico no manejo integrado de pragas. / Predatory bugs are important natural enemies of many arthropod species and they are constantly exposed to xenobiotics used for pest control. Effects of stressor agents, such as xenobiotics, on biological parameters of organisms are complex and very important. Effects of the sublethal doses 0.131, 1.315, 13.15, 131.5 and 1315 ppb of permethrin insecticide were studied on biological parameters of Podisus distinctus (Stål) (Heteroptera: Pentatomidae) when topically applied on third instar nymphs of this predator. Duration of third and fourth instars of this predator was reduced with the doses of 0.131 and 1.315 ppb of permethrin, respectively, which hormetic effect was evidenced on survival and weight of P. distinctus with the doses of 0.131, 1.315 and 13.15 ppb of permethrin during the nymphal phase of P. distinctus. Nymphs of this predator presented higher weight and survival, besides lower duration of the nynphal phase. Stimulatory effects of hormesis were also observed with higher number of eggs and nymphs per female of P. distinctus. Life fertility tables and expectancy tables showed higher values for total (TBR) and liquid (Ro) reproductivity rates in the 0.131 ppb permethrin, than in the control and in the other doses. This dose of permethrin also increased population growth of this predator per year what confirms the occurrence of hormesis. Although hormesis has been rarely reported for natural enemies in field conditions, it can be induced in laboratory aiming to improve reproductive rates and the performance of P. distinctus in biological control programs of integrated pest management. / Tese importada do Alexandria

As empresas alocam seus recursos escassos entre dois processos fundamentais: de criação de valor (ex. inovando, produzindo e entregando produtos ao mercado) e de apropriação de valor (ex. extraindo lucros do mercado). Embora ambos os processos sejam pré-requisito para a vantagem competitiva sustentável, a empresa possui considerável liberdade para decidir qual processo será enfatizado. Configura-se um trade-off estratégico que é representado por uma ênfase estratégica, ou seja, a ênfase relativa que a empresa emprega na apropriação de valor em relação à criação de valor. No entanto, poucas pesquisas exploraram o impacto desse trade-off no desempenho financeiro. Quais são os impactos da mudança da ênfase estratégica (criação de valor versus apropriação de valor) no desempenho financeiro das empresas no contexto brasileiro? Uma métrica de ênfase estratégica baseada nos gastos em P&D (criação de valor) e nos gastos de Marketing (apropriação de valor) foi testada e validada no contexto brasileiro. Em seguida, analisou-se o impacto financeiro deste trade-off por meio de cinco indicadores de desempenho (Retorno da Ação, Giro do Ativo, Margem Líquida, q de Tobin e Crescimento de Vendas) por meio de regressões múltiplas. Adicionalmente o trade-off foi investigado segundo três fatores: o ambiente tecnológico, a rentabilidade prévia e a estratégia do passado. A ênfase estratégica foi validada como indicador que mensura o trade-off entre criação de valor (exploration) e apropriação de valor (exploitation) no contexto brasileiro. Quando a empresa enfatiza mais a apropriação de valor relativamente à criação de valor, maior é o Giro do Ativo e o Crescimento das Vendas. Esses resultados podem ser fruto da administração míope de marketing, ou seja, a ênfase excessiva nos resultados de curto prazo por meio da redução dos investimentos em marketing. Isso não minimiza a relevância do processo de criação de valor, mas evidencia a importância dos mecanismos de isolamento na apropriação de parte do valor criado. Duas características da empresa se revelaram como moderadoras da relação entre a ênfase estratégica e o desempenho financeiro: a estratégia passada e a rentabilidade anterior. A estratégia anterior influencia a ênfase estratégica por meio dos retornos marginais decrescentes. As empresas que mudam sua ênfase estratégica anterior, seja criação de valor ou apropriação de valor, tendem a apresentar retornos superiores (maiores Margem Líquida, Giro do Ativo, Crescimento de Vendas e q de Tobin). Também se identificou que a rentabilidade anterior influencia a estratégia atual da empresa. Se a empresa foi lucrativa, a apropriação de valor é mantida para garantir uma Margem Líquida e um q de Tobin maiores. Por outro lado, as empresas com prejuízo se voltam à criação de valor para fomentar novas oportunidades de ganhos. Por fim, apresentam-se as limitações do estudo com a agenda de pesquisas futuras. / Firms allocate their limited resources between two fundamental processes of creating value (i.e., innovating, producing, and delivering products to the market) and appropriating value (i.e., extracting profits in the marketplace). Although both value creation and value appropriation are required for achieving sustained competitive advantage, a firm has significant latitude in deciding the extent to which it emphasizes one process over the other. There is a strategic trade-off represented by the strategic emphasis: the relative emphasis a firm places on value appropriation relative to value creation. However, few researches have explored the financial impact of this trade-off. What impact does strategic emphasis shift (i.e., emphasis on value creation versus value appropriation) have on firm‟s financial performance in the Brazilian context? A strategic emphasis metric based on the R&D spending (value creation) and on marketing spending (value appropriation) was tested and validated in the Brazilian context. Then, the financial impact of this trade-off was analyzed by five performance metrics (Stock Return, Asset Turnover, Net Margin, Tobin‟s Q and Sales Growth) by multiple regressions. In addition, the trade-off was investigated according three factors: technological environment, previous profitability and past strategy. The strategic emphasis was validated as a metric that measures the trade-off among value creation (exploration) and value appropriation (exploitation) in the Brazilian context. When the firm emphasizes more in value appropriation than the value creation, the Asset Turnover and the Sales Growth are higher. These results may occur because of the myopic marketing management, in other words, an overemphasis on the current term financial performance and the use of marketing tools to inflate current profitability measures. This doesn‟t understate the relevance of the value creation process, but rather highlight the importance of the isolating mechanisms in the appropriation of the part of the value created. Two firm‟s characteristics moderate the relation of strategic emphasis and financial performance: the past strategy and the previous profitability. The past strategy affects the strategic emphasis by the diminishing marginal returns. Firms that change their strategic emphasis (value creation or value appropriation), tend to present superior return (higher Net Margin, Asset Turnover, Sales Growth and Tobin‟s Q). Also the previous profitability influences the current firm‟s strategy. If the firm was profitable, the value appropriation is maintained to guarantee higher Net Margin and Tobin‟s Q. On the other hand, the firms with negative profitability turn to value creation to promote new opportunities of gains. Finally, research limitations and future research agenda is presented.

The new opportunities that come with the Internet as a worldwide network bring the new threats and risks for private, institutional and corporate users. Therefore, it is important to integrate the security mechanisms into a network environment. Due to the significant increase in computers speed and features of applications, the people are not able any more to make quick and adequate decisions about which security mechanisms should be applied at the moment. In most cases they choose the strongest security level available. Along with the high security this approach brings additional costs and resources consumption and drastically reduces the performance of devices with limited resources. For such devices a trade-off between performance and security should be provided. Most of the time there are no risks and threats to devices since there are not under attacks, and the use of strong security wastes the available resources. A user of computer networks and electronic devices (e.g. PCs, smartphones, PDAs) is faced with a wide range of different security mechanisms. These mechanisms differ in terms costs, complexity of used cryptographic algorithms, types of licence, processing speed, and required resources. The user has to make a decision on which security mechanism to apply. This decision is often based on user's preferences, device capabilities and available resources. While a broad range of security mechanisms has been developed to secure devices and networks, too little attention is given to actual process of making a decision about the required security level with respect to the set of predefined requirements. The main goal of this thesis is the developing of a practical decision making model for dynamic reasoning about an adequate security level providing trade-off between security and performance. The thesis presents the methodology for security metrics identification, selection and quantification. The developed approach is not limited to a particular system or number of metrics. The scheme can be used to select and quantify security metrics for any decision making models and different systems under consideration. This thesis analyses the range of decision making methods for their fitness to fulfil the main goal of this work. Three models are developed based on fuzzy reasoning, simple multi-attribute rating technique (SMART) and artificial neural networks (ANNs) for making decisions about an adequate security level. The models take into consideration the selected metrics (e.g. threat level, location, content, resources), and user's preferences and make a recommendation regarding security level. The models differ in terms number of security metrics used, user's intervention into decision making process, and number of security levels. Finally, the thesis presents the results of the experiment that has been conducted to evaluate a performance of the adaptive approach for selecting an adequate security level. The motivation for this experiment is based on the fact that decision making process requires additional computations, which can lead to increased resources consumption and can make the use of adaptive approach impractical. The results show that with right software design and implementation the computations related to adaptive approach does not decrease the performance of mobile devices. Furthermore, the use of the adequate security level improves the resources utilization for memory and battery life. The improvements are feasible already for small data rates (~3.4 Mb). Thus, for the real life scenarios with the data rates of hundred megabytes, we can expect significant improvements in resources usage by using an adequate security level / E-mail: ssmirnow@msn.com

In this thesis, I examine earnings management issues in the UK context. The thesis consists of three essays. The first chapter investigates whether managers base their trade-off decisions among real earnings management, accruals-based earnings management, and classification shifting, on the costs, constraints and timing of each strategy in the UK. The empirical evidence suggests that some, but not all, costs and constraints play a role in managers’ trade-off decisions. Further, contrasting between firms that are most likely to have manipulated earnings and firms that are not likely to have manipulated earnings, I find no difference in the relation of constraints towards all earnings management forms. This indicates that cost and constraints do not capture entirely what they are designed to, in the first place. Finally, I document evidence that is consistent with managers using real and accruals-based earnings management as substitutes but fail to find evidence that classification shifting acts as a substitute. The second essay studies the effect of income smoothing via accruals-based and real earnings management on the relationship between current stock returns, current earnings and future earnings. I measure income smoothing as the contemporaneous correlation between changes in earnings management proxies and pre-managed income. Using a sample of non-financial publicly listed firms in the UK, I show that both accruals-based and real income smoothing measures are associated with significantly positive share price anticipation of earnings. These results are robust to different stock returns specifications, income smoothing measure calculations, abnormal accruals models and accumulation periods of stock returns. In the third and final essay, I investigate the impact of the level of accruals-based and real earnings management on measures of the amount of performance commentary in annual reports for a large sample of UK public firms. I use automated textual analysis to construct disclosure scores based on the amount of performance and causal commentary. The results suggest that firms with higher levels of earnings management have lower levels of disclosure of performance and causal commentary. The presence of bad news for the firm (missed analyst forecast, underperformance or earnings decline) affects the relationship between disclosure and accruals-based earnings management but not the relationship between disclosure and real earnings management.

L'Eucalyptus, feuillu le plus planté dans le monde, est fortement exposé au froid en raison de l'absence de dormance. Les gènes DREB sont connus comme étant les principaux régulateurs de la réponse aux stress abiotiques. Un nombre élevé de gènes DREB1/CBF (C-Repeat Factor) a été identifié chez Eucalyptus grandis. Le but de l'étude est de mieux comprendre le rôle de la voie DREB chez Eucalyptus pour le contrôle de la tolérance au stress, du développement et de la formation du bois. La présente étude a permis une annotation des gènes CBF et DREB2 dans le cadre d'un projet de sequençage partiel du génome d'E. gunnii. Une analyse complète de l'expression des genes par qRT-PCR a été réalisée sur les différents organes des deux espèces d'Eucalyptus après les traitements au stress. L'existence d'une copie de CBF supplémentaire dans le génome E. gunnii par rapport à E. grandis suggère que ce groupe est encore en évolution contrairement au groupe DREB2. Un nombre élevé de transcrits CBF chez E. gunnii, tolérant au froid, et forte une vitesse d'induction ce ces facteurs chez E. grandis, à croissance rapide, suggère que les facteurs CBF sont impliqués à la fois dans la protection au stress et la limitation de croissance. Des facteurs de transcription des familles MYB, NAC, KNOX et AP2/ERF impliqués dans le contrôle de la croissance et de la formation de la paroi cellulaire ont été identifiés comme étant des gènes putatifs cibles de CBF. Ces résultats sont en accord avec le phénotype modifié de surexpresseurs CBF. Les deux approches suggèrent un rôle central de la voie de DREB dans le compromis entre la croissance et la résistance au stress chez cette espèce ligneuse. / Eucalyptus, the most widely planted hardwood in the world, is highly exposed to the cold due to the lack of dormancy. DREB (Drought Responsive Element Binding) genes are known as master regulators of abiotic stress response. A high number of the DREB1/CBF (C-Repeat Factor) genes has been annotated in Eucalyptus grandis. The aim of the study was to better understand the role of DREB pathway in Eucalyptus for the control of stress tolerance, development and wood formation. The present study provides an annotation of the CBF and DREB2 genes from a partial draft of the E. gunnii genome sequence. A comprehensive transcriptional analysis through high-throughput qRT-PCR was carried out on different organs from the two Eucalyptus species after stress treatments. An additional CBF copy in the E. gunnii genome compared to E. grandis suggests that this group is still evolving unlike the DREB2 group. The higher CBF transcript amounts in the cold tolerant E. gunnii together with higher induction rates in the fast growing E. grandis suggest that CBF factors promote both stress protection and growth limitation. In addition, transcription factors from MYB, NAC, KNOX and AP2/ERF families involved in the control of growth and cell wall formation have been identified as putative CBF target genes. These results are in agreement with the modified phenotype of CBF overexpressors. Both approaches suggest a central role of DREB pathway in the trade-off between growth and stress resistance in this woody species.