Yes / Closing remarks with Professor Shirley Congdon at the GENOVATE conference. / FP7

Nous montrons un résultat du type Closing Lemma pour les mesures non uniformément hyperboliques associées à des applications méromorphes. Nous prouvons aussi qu'il est possible d'approximer la dynamique de telles mesures par des codages du type Bernoulli. / We prove a Closing Lemma for nonuniformly hyperbolic measures of meromor-phic maps. We prove also a theorem of approxiamtion of the dynamics of such measures by Bernoulli coding maps.

Closing-in Behaviour (CIB) is the tendency observed in copying tasks, both graphic and gestural, in which the copy is made inappropriately close to or on top of the model. It is classically considered as a manifestation of Constructional Apraxia (CA) and it is often observed in patients with dementia. CIB is not only a symptom of pathology, but it is also observed in children’s first attempts at graphic copying. However, CIB shows an inverse pattern in development and dementia: while its frequency increases in severe dementia, CIB progressively decreases with development. The cognitive origins of CIB are still unclear. Two main interpretations dominate CIB literature: the compensation and the attraction hypotheses. The first hypothesis interprets CIB as a strategy specific to copying tasks that the patient adopts to overcome visuospatial and working memory deficits. In contrast, the attraction hypothesis considers CIB as a primitive behaviour, not specific to copying, and characterized by the default tendency to perform an action toward the focus of attention. This thesis aimed to study the characteristics and the cognitive origins of CIB in dementia, development and healthy adulthood. It has three main sections. The first and second sections explore CIB in patients (with Alzheimer’s disease- AD and Frontotemporal dementia) and in pre-school children, using survey and experimental studies, to investigate if CIB might have common characteristics and cognitive substrates in these different populations. The results provided converging evidence for the similar nature of CIB in development and dementia. For instance, survey studies in patients with dementia (Chapter 3) and preschool children (Chapter 6) showed that performance in attentional tasks predicted the appearance of CIB. In a similar vein, experimental studies showed support for the attraction hypothesis of CIB in a single patient with AD (Chapter 4) and pre-school children (Chapter 7 and 8). These results were not, however, replicated in a larger cohort of patients with AD due to practical reasons (Chapter 5). The last section was devoted to modelling CIB in normal participants, using complex graphic copying (Chapter 9) and dual task paradigms (Chapter 10). The results showed further support for the attraction hypothesis of CIB and underlined the difficulties of eliciting this default bias in normal adults. To conclude, this thesis radically changes the classical consideration of CIB as a manifestation of CA and demonstrates that CIB is a general default tendency, not specific to copying tasks. This work indicates avenues for new studies, which might consider the possible expression and consequences of this behaviour in patients’ daily lives.

Doctor of Philosophy (PhD) / Allegations of market manipulation abound in the popular press, particularly during the recent financial turmoil. However, many aspects of manipulation are poorly understood. The purpose of this thesis is to enhance our understanding of market manipulation by providing empirical evidence on the prevalence, effects and determinants of closing price manipulation. The first issue examined in this thesis is the prevalence of closing price manipulation. This thesis uses a hand collected sample of prosecuted closing price manipulation cases from US and Canadian stock exchanges, and methods that explicitly model the incomplete and non-random detection of manipulation. The results suggest that approximately 1.1% of closing prices are manipulated. For every prosecuted closing price manipulation there are approximately 300 instances of manipulation that remain undetected or not prosecuted. Closing price manipulation is more prevalent on larger exchanges than smaller ones, but is detected at a higher rate on small exchanges. Second, this thesis examines the effects of closing price manipulation. Using a sample of prosecution cases, this thesis finds that closing price manipulation is associated with large day-end returns, subsequent return reversals, increases in day-end spreads and increases in day-end trading activity. At the broader level of market quality, this thesis provides evidence from a laboratory experiment that closing price manipulation decreases both price accuracy and liquidity. Even the mere possibility of manipulation decreases liquidity and increases trading costs. The third issue analysed in this thesis is the determinants of closing price manipulation and its detection. Estimating an empirical model of manipulation and detection, this thesis finds that the likelihood of closing price manipulation is increased by smaller regulatory budgets, greater information asymmetry, mid to low levels of liquidity, month-end days and lower volatility. Manipulation is more likely to be detected when regulatory budgets are larger and when the manipulation causes abnormal trading characteristics. Further evidence from laboratory experiments suggests that regulation helps restore price accuracy by deterring some manipulation and making remaining manipulation less aggressive. These experiments also show that regulation has an insignificant effect on liquidity because participants in regulated markets still face relatively high uncertainty about the presence of manipulators. This thesis also examines how closing price manipulation is conducted and how other market participants respond. It develops an index of closing price manipulation that can be used to study manipulation in markets or time periods in which prosecution data are not available. It also provides a tool for the detection of manipulation, which can be used by regulators in automated surveillance systems. Finally, this thesis has implications for economic efficiency and policy. Closing price manipulation is significantly more prevalent than the number of prosecution cases suggests. Further, it harms both pricing accuracy and liquidity and therefore undermines economic efficiency. The prevalence of closing price manipulation can be reduced by increasing regulatory budgets, improving the accuracy of market surveillance systems by using the detection tools developed in this thesis, structuring markets such that participants are better able to identify manipulation, and implementing closing mechanisms that are difficult to manipulate. These actions would enhance market integrity and economic efficiency.

Doctor of Philosophy (PhD) / Allegations of market manipulation abound in the popular press, particularly during the recent financial turmoil. However, many aspects of manipulation are poorly understood. The purpose of this thesis is to enhance our understanding of market manipulation by providing empirical evidence on the prevalence, effects and determinants of closing price manipulation. The first issue examined in this thesis is the prevalence of closing price manipulation. This thesis uses a hand collected sample of prosecuted closing price manipulation cases from US and Canadian stock exchanges, and methods that explicitly model the incomplete and non-random detection of manipulation. The results suggest that approximately 1.1% of closing prices are manipulated. For every prosecuted closing price manipulation there are approximately 300 instances of manipulation that remain undetected or not prosecuted. Closing price manipulation is more prevalent on larger exchanges than smaller ones, but is detected at a higher rate on small exchanges. Second, this thesis examines the effects of closing price manipulation. Using a sample of prosecution cases, this thesis finds that closing price manipulation is associated with large day-end returns, subsequent return reversals, increases in day-end spreads and increases in day-end trading activity. At the broader level of market quality, this thesis provides evidence from a laboratory experiment that closing price manipulation decreases both price accuracy and liquidity. Even the mere possibility of manipulation decreases liquidity and increases trading costs. The third issue analysed in this thesis is the determinants of closing price manipulation and its detection. Estimating an empirical model of manipulation and detection, this thesis finds that the likelihood of closing price manipulation is increased by smaller regulatory budgets, greater information asymmetry, mid to low levels of liquidity, month-end days and lower volatility. Manipulation is more likely to be detected when regulatory budgets are larger and when the manipulation causes abnormal trading characteristics. Further evidence from laboratory experiments suggests that regulation helps restore price accuracy by deterring some manipulation and making remaining manipulation less aggressive. These experiments also show that regulation has an insignificant effect on liquidity because participants in regulated markets still face relatively high uncertainty about the presence of manipulators. This thesis also examines how closing price manipulation is conducted and how other market participants respond. It develops an index of closing price manipulation that can be used to study manipulation in markets or time periods in which prosecution data are not available. It also provides a tool for the detection of manipulation, which can be used by regulators in automated surveillance systems. Finally, this thesis has implications for economic efficiency and policy. Closing price manipulation is significantly more prevalent than the number of prosecution cases suggests. Further, it harms both pricing accuracy and liquidity and therefore undermines economic efficiency. The prevalence of closing price manipulation can be reduced by increasing regulatory budgets, improving the accuracy of market surveillance systems by using the detection tools developed in this thesis, structuring markets such that participants are better able to identify manipulation, and implementing closing mechanisms that are difficult to manipulate. These actions would enhance market integrity and economic efficiency.

The purpose of this qualitative, single case study was to identify leadership practices and processes that contributed to the success of a single High Needs, Title 1 elementary school that has experienced acknowledged superior academic success, particularly for its minoritized and low socioeconomically disadvantaged students, as indicated by the school's success on the State of Texas Assessment of Academic Readiness (STAAR) tests. The study sought to explore the principal's and teachers' conception of leadership for success and to examine what effective practices and processes were employed at a high-needs, high-performing campus that accounted for its success. The study applied the culturally responsive school leadership (CRSL) framework to analyze the practices employed at the school. Results of the study, from interviews with the principal and a focus group of three teachers, indicated that not only did they apply the principles of the CRSL framework, which employed the critical self awareness, culturally responsive curricula and teacher preparation in a culturally responsive and inclusive school environment which engaged parents and students in community contexts, but they also enhanced their effectiveness through the provision of additional resources for teachers and students, with a heavy reliance on data to guide academic decisions.

In a small rural school division in Virginia, three small high schools were consolidated into one medium-sized high school in the fall of 1992. This study examined that consolidation. The research question was: What happened when three small high schools consolidated into one medium-sized high school? Data were collected from the following sources through: interviews with key actors of the consolidation process; surveys of students, teachers, and parents; and, public documents. Results of the study include: (1) Prior to consolidation some key actors favored and others opposed the consolidation. Their opinions did not change following the consolidation. (2) Some of the advantages articulated by the proponents and some of the disadvantages articulated by the opponents were realized. (3) Student outcomes did not change. (4) The number of teacher preparations decreased and the student/teacher ratio increased, but not to the point of exceeding state guidelines. (5) Transportation costs increased. (6) Expenses for Administration, Instruction, Operation and Maintenance, and Facilities decreased. (7) Time on the bus did not change. Any locality that is considering a consolidation must identify the issues and concerns that are important to that locality. Those issues and concerns will vary location to location and should constitute the components of any subsequent evaluation. / Ed. D.

Let f be a C2 local diffeomorphism, of a closed surface M without zero Lyapunov exponents. We have proved that the number of ergodic hyperbolic measures of f with SRB property is less than equal to the number of homoclinic equivalence classes. We use an adaptation of Katok closing lemma for endomorphisms and prove ergodic criterion, introduced in [HHTU], for endomorphisms. We also prove some folklore results on uniqueness of SRB measures, in the presence of topological transitivity / Seja f um endomorfismo C2 non-singular (difeomorfismo local), de uma superfície fechada M e µ uma medida probabilidade Borel f-invariante e ergódica com expoentes de Lyapunov Não nulo. Nós provamos que o número de medidas hiperbólicas com propriedade SRB é para f so menor ou igual ao número de classes equivalentes homoclínicos. Usamos uma adaptaão do closing lema de Katok por endomorfismos e provamos critrio ergódico, introduzido em [HHTU], para endomorfismos. Também provamos alguns resultados folclóricos em unicidade de medidas SRB, na presena de transitividade topológica vii

Let f be a C2 local diffeomorphism, of a closed surface M without zero Lyapunov exponents. We have proved that the number of ergodic hyperbolic measures of f with SRB property is less than equal to the number of homoclinic equivalence classes. We use an adaptation of Katok closing lemma for endomorphisms and prove ergodic criterion, introduced in [HHTU], for endomorphisms. We also prove some folklore results on uniqueness of SRB measures, in the presence of topological transitivity / Seja f um endomorfismo C2 non-singular (difeomorfismo local), de uma superfície fechada M e µ uma medida probabilidade Borel f-invariante e ergódica com expoentes de Lyapunov Não nulo. Nós provamos que o número de medidas hiperbólicas com propriedade SRB é para f so menor ou igual ao número de classes equivalentes homoclínicos. Usamos uma adaptaão do closing lema de Katok por endomorfismos e provamos critrio ergódico, introduzido em [HHTU], para endomorfismos. Também provamos alguns resultados folclóricos em unicidade de medidas SRB, na presena de transitividade topológica vii

Neste trabalho reunimos alguns resultados afirmativos relacionados ao closing lemma de classe C^r em variedades bidimensionais compactas. / In this work we present some partial results corcerning closing lemma for smooth flows on compact bidimensional manifolds.