The main aim of this thesis is to analyze variations and adjustments under FIDIC contractual conditions, especially in relation to the private law limits of the Czech legal order. The goal of this analysis is to answer the question whether variations as a special contractual institute are permissible and validly applicable in the framework of construction projects realized in the Czech Republic. The thesis is clearly divided into five main chapters, which are systematically structured from the general introduction to basic issues through the main analysis of variations and adjustments to specific examples of their use in practice. The first and the second chapters briefly present the FIDIC organization and its issued sample contractual conditions, with a brief discussion of most of the sample books. The contractual conditions are also set in the context of Czech law, where emphasis is placed on distinguishing the business terms from FIDIC contractual conditions. In this chapter, the examples of use of the individual sample books in the Czech Republic are also mentioned. In the third chapter, the institute of variations and adjustments according to individual sample books is analyzed in detail. With the exception of the general description of the variation process, the thesis is focused on a...

Elever med dyslexi har i svensk skola rätt till extra anpassningar, vilka ska svara upp mot elevernas behov gällande stöd för läsning och skrivning. I den här studien har vi utifrån en fenomenografisk forskningsansats undersökt hur elever i åk 5 - 6 med dyslexi beskriver sina extra anpassningar gällande läsning och skrivning med avseende på delaktighet och motivation. Åtta elever i tre mellansvenska skolor intervjuades enskilt. Den kvalitativa analysen av elevsvaren resulterade i ett utfall av sammanlagt tolv beskrivningskategorier, var och en bestående av varierade uppfattningar. Av dessa beskrivningskategorier utgör åtta kategorier elevers beskrivningar av sina extra anpassningar och vad som motiverat till läsning och skrivning eller inte utifrån dessa. Resultatet visar på lärarens betydelse för elevernas motivation utifrån de extra anpassningar som ges genom förmågan att anpassa utifrån elevens behov, vilka kan variera utifrån situation och skolämne. Resultatet visade även på betydelsen av teknik som stöd för läsning och skrivning samt att arbetet med en kamrat är den extra anpassning som eleverna beskriver påverkar arbetet med läsning och skrivning mest. Utfallet av elevernas beskrivningar gällande upplevelsen av delaktighet i valet av, genomförandet samt utvärderingar av sina extra anpassningar resulterade i fyra beskrivningskategorier. Resultatet visade på att eleverna i olika omfattning är delaktiga i utformandet av sina extra anpassningar. Vidare visade resultatet att upplevelsen av delaktighet till stor del påverkas av relationen mellan lärare och elev samt acceptans och erkännande från både lärare och skolkamrater. / Pupils with dyslexia have the right to special adjustments in Swedish schools, depending on the pupil´s needs regarding support for reading and writing. In this study we have, on the basis of a phenomenographic research approach, identified how pupils in grade 5–6 with dyslexia describe their adaptations for reading and writing with regard to participation and motivation. Data was collected through individual interviews with eight students in three Swedish schools. The observations were then examined using a qualitative method of analysis, which resulted in a total of twelve description categories, each containing varied perceptions. Of these description categories, eight categories represent students' descriptions of their extra adaptations and what motivates and discourages reading and writing. The results show the importance of working together with a classmate, which is the extra adaptation that the students describe as affecting their reading and writing the most. Furthermore, the students describe the importance of the teacher for motivating reading and writing, based on the teacher's ability to adapt to the student's needs, which can vary depending on the situation and discipline. The use of assistive technology as support for reading and writing was, according to the students, another important motivating factor. The outcome of the pupils descriptions regarding the level of participation in the choice, implementation and evaluations of their extra adaptations resulted in four description categories. The results showed that the pupils are involved in the design of their extra adaptations to varying degrees. Furthermore, the result showed that the level of participation is largely influenced by the relationship between teacher and student as well as acceptance and recognition from both teachers and schoolmates.

A teoria do valor extremo é aplicada em áreas de pesquisa tais como hidrologia, estudos de poluição, engenharia de materiais, controle de tráfego e economia. A distribuição valor extremo ou Gumbel é amplamente utilizada na modelagem de valores extremos de fenômenos da natureza e no contexto de análise de sobrevivência para modelar o logaritmo do tempo de vida. A modelagem de valores extremos de fenômenos da natureza tais como velocidade de vento, nível da água de rio ou mar, altura de onda ou umidade é importante em estatística ambiental pois o conhecimento de valores extremos de tais eventos é crucial na prevenção de catátrofes. Ultimamente esta teoria é de particular interesse pois fenômenos extremos da natureza têm sido mais comuns e intensos. A maioria dos artigos sobre teoria do valor extremo para modelagem de dados considera amostras de tamanho moderado ou grande. A distribuição Gumbel é frequentemente incluída nas análises mas a qualidade do ajuste pode ser pobre em função de presença de ouliers. Investigamos modelagem estatística de eventos extremos com base na teoria de valores extremos. Consideramos um modelo de regressão valor extremo introduzido por Barreto-Souza & Vasconcellos (2011). Os autores trataram da questão de corrigir o viés do estimador de máxima verossimilhança para pequenas amostras. Nosso primeiro objetivo é deduzir ajustes para testes de hipótese nesta classe de modelos. Derivamos a estatística da razão de verossimilhanças ajustada de Skovgaard (2001) e cinco ajustes da estatística da razão de verossimilhanças sinalizada, que foram propostos por Barndorff-Nielsen (1986, 1991), DiCiccio & Martin (1993), Skovgaard (1996), Severini (1999) e Fraser et al. (1999). As estatísticas ajustadas são aproximadamente distribuídas como uma distribuição $\\chi^2$ e normal padrão com alto grau de acurácia. Os termos dos ajustes têm formas compactas simples que podem ser facilmente implementadas em softwares disponíveis. Comparamos a performance do teste da razão de verossimilhanças, do teste da razão de verossimilanças sinalizada e dos testes ajustados obtidos neste trabalho em amostras pequenas. Ilustramos uma aplicação dos testes usuais e suas versões modificadas em conjuntos de dados reais. As distribuições das estatísticas ajustadas são mais próximas das respectivas distribuições limites comparadas com as distribuições das estatísticas usuais quando o tamanho da amostra é relativamente pequeno. Os resultados de simulação indicaram que as estatísticas ajustadas são recomendadas para inferência em modelo de regressão valor extremo quando o tamanho da amostra é moderado ou pequeno. Parcimônia é importante quando os dados são escassos, mas flexibilidade também é crucial pois um ajuste pobre pode levar a uma conclusão completamente errada. Uma revisão da literatura foi feita para listar as distribuições que são generalizações da distribuição Gumbel. Nosso segundo objetivo é avaliar a parcimônia e flexibilidade destas distribuições. Com este propósito, comparamos tais distribuições através de momentos, coeficientes de assimetria e de curtose e índice da cauda. As famílias mais amplas obtidas pela inclusão de parâmetros adicionais, que têm a distribuição Gumbel como caso particular, apresentam assimetria e curtose flexíveis enquanto a distribuição Gumbel apresenta tais características constantes. Dentre estas distribuições, a distribuição valor extremo generalizada é a única com índice da cauda que pode ser qualquer número real positivo enquanto os índices da cauda das outras distribuições são zero. Observamos que algumas generalizações da distribuição Gumbel estudadas na literatura são não identificáveis. Portanto, para estes modelos a interpretação e estimação de parâmetros individuais não é factível. Selecionamos as distribuições identificáveis e as ajustamos a um conjunto de dados simulado e a um conjunto de dados reais de velocidade de vento. Como esperado, tais distribuições se ajustaram bastante bem ao conjunto de dados simulados de uma distribuição Gumbel. A distribuição valor extremo generalizada e a mistura de duas distribuições Gumbel produziram melhores ajustes aos dados do que as outras distribuições na presença não desprezível de observações discrepantes que não podem ser acomodadas pela distribuição Gumbel e, portanto, sugerimos que tais distribuições devem ser utilizadas neste contexto. / The extreme value theory is applied in research fields such as hydrology, pollution studies, materials engineering, traffic management, economics and finance. The Gumbel distribution is widely used in statistical modeling of extreme values of a natural process such as rainfall and wind. Also, the Gumbel distribution is important in the context of survival analysis for modeling lifetime in logarithmic scale. The statistical modeling of extreme values of a natural process such as wind or humidity is important in environmental statistics; for example, understanding extreme wind speed is crucial in catastrophe/disaster protection. Lately this is of particular interest as extreme natural phenomena/episodes are more common and intense. The majority of papers on extreme value theory for modeling extreme data is supported by moderate or large sample sizes. The Gumbel distribution is often considered but the resulting fit may be poor in the presence of ouliers since its skewness and kurtosis are constant. We deal with statistical modeling of extreme events data based on extreme value theory. We consider a general extreme-value regression model family introduced by Barreto-Souza & Vasconcellos (2011). The authors addressed the issue of correcting the bias of the maximum likelihood estimators in small samples. Here, our first goal is to derive hypothesis test adjustments in this class of models. We derive Skovgaard\'s adjusted likelihood ratio statistics Skovgaard (2001) and five adjusted signed likelihood ratio statistics, which have been proposed by Barndorff-Nielsen (1986, 1991), DiCiccio & Martin (1993), Skovgaard (1996), Severini (1999) and Fraser et al. (1999). The adjusted statistics are approximately distributed as $\\chi^2$ and standard normal with high accuracy. The adjustment terms have simple compact forms which may be easily implemented by readily available software. We compare the finite sample performance of the likelihood ratio test, the signed likelihood ratio test and the adjusted tests obtained in this work. We illustrate the application of the usual tests and their modified versions in real datasets. The adjusted statistics are closer to the respective limiting distribution compared to the usual ones when the sample size is relatively small. Simulation results indicate that the adjusted statistics can be recommended for inference in extreme value regression model with small or moderate sample size. Parsimony is important when data are scarce, but flexibility is also crucial since a poor fit may lead to a completely wrong conclusion. A literature review was conducted to list distributions which nest the Gumbel distribution. Our second goal is to evaluate their parsimony and flexibility. For this purpose, we compare such distributions regarding moments, skewness, kurtosis and tail index. The larger families obtained by introducing additional parameters, which have Gumbel embedded in, present flexible skewness and kurtosis while the Gumbel distribution skewness and kurtosis are constant. Among these distributions the generalized extreme value is the only one with tail index that can be any positive real number while the tail indeces of the other distributions investigated here are zero. We notice that some generalizations of the Gumbel distribution studied in the literature are not indetifiable. Hence, for these models meaningful interpretation and estimation of individual parameters are not feasible. We select the identifiable distributions and fit them to a simulated dataset and to real wind speed data. As expected, such distributions fit the Gumbel simulated data quite well. The generalized extreme value distribution and the two-component extreme value distribution fit the data better than the others in the non-negligible presence of outliers that cannot be accommodated by the Gumbel distribution, and therefore we suggest them to be applied in this context.

Before the 2008 financial crisis, most research in financial mathematics focused on the risk management and the pricing of options without considering effects of counterparties’ default, illiquidity problems, systemic risk and the role of the repurchase agreement (Repo). During the 2008 financial crisis, a frozen Repo market led to a shutdown of short sales in the stock market. Cyclical interdependencies among financial corporations caused that a default of one firm seriously affected other firms and even the whole financial network. In this dissertation, we will consider financial markets which are shaped by financial crisis. This will be done from two distinct perspectives, an investor’s and a regulator’s. From an investor’s perspective, recently models were proposed to compute the total valuation adjustment (XVA) of derivatives without considering a potential crisis in the market. In our research, we include a possible crisis by apply an alternating renewal process to describe a switching between a normal financial status and a financial crisis status. We develop a framework for pricing the XVA of a European claim in this state-dependent framework. We represent the price as a solution to a backward stochastic differential equation and prove the existence and uniqueness of the solution. To study financial networks from a regulator’s perspective, one popular method is the fixed point based approach by L. Eisenberg and T. Noe. However, in practice, there is no accurate record of the interbank liabilities and thus one has to estimate them to use Eisenberg - Noe type models. In our research, we conduct a sensitivity analysis of the Eisenberg - Noe framework, and quantify the effect of the estimation errors to the clearing payments. We show that the effect of the missing specification of interbank connection to clearing payments can be described via directional derivatives that can be represented as solutions of fixed point equations. We also compute the probability of observing clearing payment deviations of a certain magnitude.

Genetische Polymorphismen in den Enzymen CYP2D6, CYP2C19 und CYP2C9 beeinflussen die Pharmakokinetik medizinisch bedeutsamer Arzneimittel wie Antidepressiva, oraler Antidiabetika und nichtsteroidaler Antiphlogistika in erheblichem Ausmaß. In der Zukunft kann die Bestimmung genetischer Varianten bei Patienten zur Verbesserung der Arzneitherapie genutzt werden, jedoch nur dann, wenn klinische Konsequenzen wie konkrete Therapieempfehlungen aus den genetischen Daten abgeleitet werden können. An gesunden Probanden wurde die die Bedeutung der beiden Aminosäurevarianten des Enzyms CYP2C9, Arg144Cys (CYP2C9*2) und Leu359Ile (CYP2C9*3) für die Pharmakokinetik von Tolbutamid, Glibenclamid, Nateglinid, Diclofenac, Ibuprofen, Celecoxib und Fluvastatin untersucht. Die Analyse der pharmakokinetischen Parameter ergab eine erheblich erniedrigte Clearance für diese Substrate bei homozygoten Trägern der Allelvariante CYP2C9*3, wie sie etwa 1% in der Bevölkerung tragen. Um bioäquivalente Konzentrationsverläufe zu erreichen, müssten diese Patienten deutlich niedrigere Dosierungen (unter 50%) der meisten der untersuchten CYP2C9-Substrate erhalten. Hingegen zeigte die CYP2C9*2-Variante nur einen geringen Einfluss auf die Pharmakokinetik der untersuchten Medikamente. Für den Bereich der Therapie mit Antidepressiva und Antipsychotika sollte untersucht werden, inwieweit umfassende pharmakogenetisch begründete Therapieempfehlungen gegeben werden können. Eine systematische Analyse aller bisher publizierten Daten zum Einfluss von Polymorphismen von CYP2D6, CYP2C19 und CYP2C9 ergab, dass für die meisten gängigen Antidepressiva bereits Studien zur Bedeutung von Cytochrom-P450-Polymorphismen durchgeführt wurden. Für die beiden in Deutschland sehr häufig verwendeten Trizyklika Trimipramin und Doxepin dagegen lagen keine ausreichenden Daten vor. Beide Medikamente wurden deshalb bei Probanden getestet, die jeweils Träger eines oder zweier Allele mit defizienter oder herabgesetzter Enzymaktivität von CYP2D6, CYP2C19 oder CYP2C9 waren. Es ergab sich ein deutlicher Einfluss des CYP2D6-Genotyps, ein schwächerer von CYP2C19 und des Genotyps CYP2C9*3/*3. Eine Dosisreduktion für Langsam-Metabolisierer von CYP2D6 und etwas moderater für Langsam-Metabolisierer von CYP2C19, sowie für Träger des Genotyps CYP2C9*3/* erscheint für diese beiden Antidepressiva sinnvoll. Die eigenen Daten und die Daten für andere Antidepressiva aus der Literatur wurden dazu verwendet, eine Methode zur Ableitung von pharmakogenetisch basierten Dosierungsempfehlungen zu entwickeln. Auf dem Prinzip der Bioäquivalenz basierend wurden Dosierungsanpassungen für unterschiedliche Genotypen je nach Unterschieden in der Clearance von Substanzen errechnet. Durch diese Dosierungsanpassungen können zumindest theoretisch die durch herabgesetzte Enzymaktivität verursachten Unterschiede in den Plasmakonzentrationsverläufen von Medikamenten ausgeglichen werden. Dabei wurden aktive an der Arzneimittelwirkung teilhabende Metaboliten mit berücksichtigt. Auf Seiten der Pharmakodynamik wurden die vielen Studien zu genetischen Polymorphismen in Serotonin-, Dopaminrezeptoren und Transportern und auch zu anderen Kandidatengenen für die Antidepressiva-, und Antipsychotikawirkung analysiert. Jedoch lassen sich aus den teilweise geringen Einflüssen einzelner Genotypen auf die Arzneimittelwirkung derzeit noch keine pharmakodynamisch begründeten Therapieempfehlungen ableiten. Zusammenfassend lassen sich also bereits heute pharmakogenetisch basierte Dosierungsempfehlungen für viele Medikamente berechnen. Derartige Empfehlungen müssen prospektiv überprüft, validiert und angepasst werden. Auf Seiten der Zielmoleküle der Arzneimittelwirkung ist eine Ableitung genetisch basierter Therapieempfehlungen schwieriger. Das Ziel, konkrete Therapieempfehlungen aus genetischen Daten abzuleiten, ist eine notwendige Bedingung, um Pharmakogenetik in die klinische Praxis der Arzneitherapie einzuführen. / Genetic polymorphisms of the cytochrome P450 enzymes CYP2D6, CYP2C19 and CYP2C9 largely influence pharmacokinetics of clinically important drugs such as antidepressants, oral antidiabetics and nonsteroidal antiphlogistic drugs. Pharmacogenetic diagnostics is ready to be used for optimization of drug treatment in the future if concise recommendations for clinical decisions can be derived from the genetic data. Panel studies in healthy volunteers served to characterize the impact of the amino acid variants Arg144Cys (CYP2C9*2) and Leu359Ile (CYP2C9*3) in cytochrome P450 2C9 on pharmacokinetics of the oral antidiabetics tolbutamide, glyburide and nateglinide, of the nonsteroidal analgetic drugs diclofenac, ibuprofen, celecoxib, and of fluvastatin. Analysis of pharmacokinetic parameters revealed largely reduced oral clearances in homozygous carriers of the CYP2C9*3 allele for most of the substrates studied. About 1% in the general population are carriers of this genotype and patients should get about 50% lower doses of most of the CYP2C9 substrates in order to achieve similar plasma concentration versus time courses. In contrast, the CYP2C9*2 variant had little influence on pharmacokinetics of the CYP2C9 substrates. For antidepressant and antipsychotic drug therapy, the aim was to derive detailed dose recommendations from the large amount of data existing. Thus, a systematic analysis of all published data on the clinical influence of genetic polymorphisms in CYP2D6, CYP2C19 and CYP2C9 was performed and dose recommendations were given for many antidepressants. For two substances, the tricyclics doxepin and trimipramine, no pharmacogenetic data have been found, and therefore own clinical studies were performed. Healthy volunteers who were heterozygous and homozygous carriers of alleles with deficient activity of CYP2D6, CYP2C19 or CYP2C9 were tested for differences in metabolism and elimination of doxepin and trimipramine and compared to carriers of the wildtype. A significant influence of the CYP2D6 genotype was detected whereas CYP2C19 and the genotype CYP2C9*3/*3 had smaller influences. A significant dose reduction for CYP2D6 poor metabolizers and a smaller reduction for CYP2C19 poor metabolizers would be predicted from these data. According the principles of bioequivalence, calculation methods for pharmacogenetic based dose recommendations from clearance or drug concentration data were developed. Using all published data and the own study results, we developed dose adjustments for each genotype. These dose adjustments would allow to compensate for lower drug clearance caused by genetic variants. Active metabolites which contribute to overall drug effects were considered as well. With regard to target molecules of antidepressant and antipsychotic drug action, many studies have been performed on genetic polymorphisms in serotonin-, and dopamine receptors and in transporter molecules but as well in other candidate genes. However, it is not yet possible to derive therapeutic consequences based on these data. In conclusion, on the pharmacokinetic side of drug action, we are already able to give pharmacogenetic based therapeutic recommendations by adjusting the doses according to genotype. However, the benefit of pharmacogenetic dose adjustments has to be studied prospectively. With regard to the pharmacodynamic side of drug action, the situation is much more complex and we are not yet ready to give pharmacogenetics based therapeutic guidelines. However, this has to be a major goal in order to introduce pharmacogenetic diagnostic into clinical practice.

Die Dissertation handelt über Wettbewerbsökonomie. Kapitel 1 betrachtet eine Fusion zwischen zwei regulierten Firmen, die in getrennten Märkten agieren und jeweils mit unregulierten Firmen konkurrieren. Die optimale Fusionspolitik für regulierte Firmen hängt von der Intensität des Wettbewerbs zwischen den unregulierten Firmen ab, verschärfter Wettbewerb zwischen den unregulierten Firmen induziert eine mildere Fusionspolitik. Das Gegenteil gilt, wenn die regulierten Firmen in ein wettbewerbsfähiges Marktsegment expandieren und die regulierten und unregulierten Waren komplementär sind. Kapitel 2 untersucht die optimale Fusionspolitik zwischen zwei wettbewerbsfähigen Firmen. Unter den strukturellen Auflagen, die sich am effektivsten herausgestellt haben um einen wirksamen Wettbewerb wiederherzustellen, gibt es eine die sich stark hervorhebt, nämlich die Veräußerung von differenzierten Marken an andere Wettbewerber. Dies ist eine effektive Möglichkeit, um die Marktmacht der neuen Firma zu verringern und sie kann die Möglichkeiten für privat und sozial wünschenswerte Fusionen erhöhen. Vor allem wenn die Güter annähernd perfekt substituierbar sind, ist der Bereich der Effizienzgewinne, die eine Fusion unter Auflagen erlauben, größer. Kapitel 3 untersucht die allgemein etablierte Feststellung, dass Einzelhandelspreise sich schneller anpassen, wenn Input Preise steigen, als wenn sie fallen. Durch die Anwendung eines dynamischen zwei Perioden Preiswettbewerb Modells zeigt sich das Folgende für die Angebotsseite für asymmetrische Preisanpassung: die Existenz von profitablen Lagerungsmöglichkeiten ermöglicht es wettbewerbsfähigen Firmen sich glaubhaft zu verpflichten, ihre Preise umgehend über die marginalen Kosten zu setzen, wenn sie höhere Input Preise antizipieren. Dies lockert den Wettbewerb sodass Firmen positive Gewinne erzielen. Wenn erwartet wird das Input Preise sinken, landen die Firmen im Bertrand Paradoxon und die Preisanpassung erfolgt langsamer. / This thesis is about competition economics. Chapter 1 considers a merger between two regulated firms operating in two separate markets, and in each market there are unregulated competitors. The optimal merger policy for regulated firms depends on the intensity of competition between unregulated firms, fiercer competition between unregulated firms induces a more lenient merger policy. These results are reversed if the regulated firms expand into a competitive segment of the market and the regulated and unregulated goods are complements. Chapter 2 studies the optimal merger policy between two competitive firms. Among the structural remedies which have being treated as the most effective manners to restore effective competition, there is one relevant type, namely, the divestiture of differentiated brands to other competitor(s). It is a powerful tool to lessen the merged entity''s market power and can increase the scope for privately and socially desirable mergers. In particular, when goods are closer to perfect substitutability, the range of the efficiency gains which allows the merger with remedies to be approved is larger. Chapter 3 investigates the well-established observation that retail prices adjust faster when input costs rise than when they fall. From the supply side to asymmetric price adjustments, using a model of two-period dynamic price competition, it shows that the presence of profitable storing allows competitive firms to credibly commit to immediately increase their prices above current marginal costs when they anticipate higher input costs. This relaxes competition and firms earn positive profits. If input costs are expected to decline, the firms are trapped in the Bertrand paradox and price adjustment is slower.

A ampla divulgação do conceito de valor econômico adicionado (EVA®) fez com que as empresas utilizassem essa medida de desempenho para evidenciar o quanto de valor foi adicionado aos seus proprietários. Essas empresas esperam que EVA®s positivos aumentem o valor da empresa no mercado. Nesse sentido, alguns estudos comprovaram uma relação forte entre o EVA® e o retorno das ações no mercado, confirmando que o EVA® positivo valoriza a empresa no mercado (FELTHAM et al, 2004; SILVEIRA et al, 2004). Entretanto, ao se analisarem as medidas contábeis tradicionais, como lucro líquido e fluxo de caixa operacional, encontra-se uma forte relação dessas medidas com o retorno das ações e uma fraca relação do EVA® com o retorno das ações (BIDDLE et al, 1997). Neste trabalho, foi aplicado o estudo de Biddle et al, para todas as empresas não-financeiras de capital aberto listadas na Bovespa, no período de 1997 a 2006. Foi apurado o lucro líquido, o fluxo de caixa operacional, o EVA® e o lucro residual (EVA® sem ajustes contábeis) e foi analisada a relação dessas medidas com o retorno das ações das empresas brasileiras. Foi analisada também a influência dos ajustes contábeis na explicação do retorno das ações, para o mesmo período. Os testes de regressões com efeito fixo e efeito aleatório para as amostras com as variáveis independentes ajustadas e não-ajustadas mostraram que o poder de explicação, medido pelo r-quadrado, encontrado nos testes foi muito baixo. Este resultado se aproximou do encontrado por Biddle et al e Feltham et al, fato este que não permitiu afirmar claramente o quanto as medidas de valor econômico e as medidas contábeis explicaram o retorno das ações e se afastou dos resultados encontrados por Silveira et al fato este que poderia evidenciar que o mercado brasileiro apresentou alguma eficiência na sua forma semi-forte. / The huge propagation of the EVA® (Economic Value Added) concept allows companies to use this performance measure to prove how much value was added for the owners. These companies hope positive EVA®s increase firm values in the market. In this direction, some studies prove a strong association between EVA® and stock returns, confirming that the positive EVA® valorizes companies in the market (Felthan et al, 2004; Silveira et al, 2004). However, when analyzing mandated performance measures, such as earning and operate cash flow, there is a strong association between these measures and the stock returns, and a weak association between EVA® and stock returns (Biddle et al, 1997). At this study, Biddle et al study was applied to all of no-financial companies with open capital listed at Bovespa, from 1997 to 2006. Earning, operate cash flow, EVA® and residual income (EVA® without accounting adjustments) were verified, and the association between these measures and Brazilian company stock returns was analyzed. The influence of accounting adjustments in the explanation of stock returns was analyzed too, in the same period of time. The tests of fixed effect regression and random effect regression for the samples with independent, adjusted and non-adjusted variables showed that the explanation power, measured by r-square, found in the tests, was very low. This result got closer to the results presented by Biddle et al, which did not allow clearly stating how much the economic value and accounting measures explain the stock returns. In the other hand, this result got far from the results presented by Silveira et al, which could prove that Brazilian market has some efficiency in its semistrong-form.

O presente trabalho considera o problema de fazer inferência com acurácia para pequenas amostras, tomando por base a estatística da razão de verossimilhanças em modelos de regressão beta. Estes, por sua vez, são úteis para modelar proporções contínuas que são afetadas por variáveis independentes. Deduzem-se as estatísticas da razão de verossimilhanças ajustadas de Skovgaard (Scandinavian Journal of Statistics 28 (2001) 3-32) nesta classe de modelos. Os termos do ajuste, que têm uma forma simples e compacta, podem ser implementados em um software estatístico. São feitas simulações de Monte Carlo para mostrar que a inferência baseada nas estatísticas ajustadas propostas é mais confiável do que a inferência usual baseada na estatística da razão de verossimilhanças. Aplicam-se os resultados a um conjunto real de dados. / We consider the issue of performing accurate small-sample likelihood-based inference in beta regression models, which are useful for modeling continuous proportions that are affected by independent variables. We derive Skovgaards (Scandinavian Journal of Statistics 28 (2001) 3-32) adjusted likelihood ratio statistics in this class of models. We show that the adjustment terms have simple compact form that can be easily implemented from standard statistical software. We presentMonte Carlo simulations showing that inference based on the adjusted statistics we propose is more reliable than that based on the usual likelihood ratio statistic. A real data example is presented.

Il est connu que le mouvement volontaire entraîne une perturbation de la posture, qui nécessite d'être compensée par des mouvement contre-perturbateurs définis comme " ajustements posturaux ". Ce processus dynamique, qui se produit avant, pendant et après le mouvement focal, nécessite la mobilité de la chaîne posturale, avec un patron spécifique pour chaque tâche.L'objectif de cette thèse de doctorat a été d'explorer l'influence de la mobilité du rachis sur les composantes focale et posturale du transfert assis- debout, ou sit-to-stand (STS), qui est une tâche indispensable à l'autonomie fonctionnelle. Trois séries expérimentales ont évalué l'effet d'une restriction de mobilité de la colonne vertébrale sur les ajustements posturaux anticipateurs (APAs) et le mouvement focal de la tâche de STS réalisée à vitesse maximale. Des paramètres biomécaniques ont été calculés à partir des données fournies par un plateau de forces et un capteur de pression. La première série a évalué l'effet de la mobilité lombo-pelvienne au moyen de trois types de contentions lombaires, et a montré qu'une réduction du jeu articulaire de cette région était associée des APAs plus longs et plus amples, ainsi qu'à une augmentation de la durée du mouvement focal. La seconde série a mis en évidence les mêmes variations en explorant l'influence de la mobilité de la colonne cervicale au moyen de trois contentions cervicales. La dernière série s'est focalisée sur le rôle de l'augmentation de la tension musculaire le long du tronc, en utilisant un protocole spécifique de compression bimanuelle. Les résultats ont montré qu'une tension musculaire plus élevée induisait une augmentation de la durée des APAs mais sans variation de la durée du mouvement focal. L'ensemble de ces résultats suggèrent que la colonne cervicale et la colonne lombaire sont à la fois impliquées dans les composantes focale et posturale du STS, et que le maintien de leur mobilité peut favoriser l'autonomie fonctionnelle. En revanche, l'augmentation de la tension musculaire le long du tronc nécessite uniquement une réorganisation des ajustements posturaux pour maintenir le même niveau de performance. / It is well known that voluntary movements induce internal disturbances to posture, which need to be balanced by counter-pertubing movements defined as " postural adjustments ". This dynamic process, which occurs before, during, and after the focal movement, requires the mobility of the postural chain, with a specific pattern for each task. The aim of this PhD thesis was to explore the influence of spine mobility on the focal and postural components of the sit-to-stand (STS) task, which is instrumental for functional autonomy. Three series of experiments assessed the effect of spine mobility restriction on anticipatory postural adjustments (APAs) and focal movement (FM) of the STS task peformed at maximum velocity. Biomechanical parameters were calculated from force plate, and pressure sensor data. The first series assessed the effect of lumbo-pelvic mobility using three different lumbar contentions, and showed that restricted articular free play in this area was associated with longer and larger APAs, along with a higher duration of the focal movement. The second series of experiment showed the same variations when exploring the effect of cervical spine mobility using three different cervical contentions. The last series focused on the effect of increased muscular tension along the trunk, using a specific bimanual compressive load paradigm.The results showed that higher tension lead to longer APAs with no variation of FM duration. Taken together, these findings suggest that the lumbar and cervical spine are involved in both the focal and postural components of the STS task, and that preserving their articular free play might be useful to favour functionnal autonomy. In contrast, increased muscular tension along the trunk only require a reorganization of the APAs to keep the same level of task performance.

O presente trabalho considera o problema de fazer inferência com acurácia para pequenas amostras, tomando por base a estatística da razão de verossimilhanças em modelos de regressão beta. Estes, por sua vez, são úteis para modelar proporções contínuas que são afetadas por variáveis independentes. Deduzem-se as estatísticas da razão de verossimilhanças ajustadas de Skovgaard (Scandinavian Journal of Statistics 28 (2001) 3-32) nesta classe de modelos. Os termos do ajuste, que têm uma forma simples e compacta, podem ser implementados em um software estatístico. São feitas simulações de Monte Carlo para mostrar que a inferência baseada nas estatísticas ajustadas propostas é mais confiável do que a inferência usual baseada na estatística da razão de verossimilhanças. Aplicam-se os resultados a um conjunto real de dados. / We consider the issue of performing accurate small-sample likelihood-based inference in beta regression models, which are useful for modeling continuous proportions that are affected by independent variables. We derive Skovgaards (Scandinavian Journal of Statistics 28 (2001) 3-32) adjusted likelihood ratio statistics in this class of models. We show that the adjustment terms have simple compact form that can be easily implemented from standard statistical software. We presentMonte Carlo simulations showing that inference based on the adjusted statistics we propose is more reliable than that based on the usual likelihood ratio statistic. A real data example is presented.