Tesis sobre el tema "Cognitive precursor"

The purpose of the present study was to explore the influence of trust, help seeking/help giving, and relation-inferred self-efficacy on the onset of flow experience in a dyadic relationship between an elite athlete and their coach. The social cognitive theory of triadic reciprocal determinism was used to examine the relationship of the elite athlete and their trusted coach in a high-pressure athletic environment as it related to the ability of the elite athlete to achieve a flow state. Using a multiple case study approach, semi-structured interviews were conducted with five coach-athlete dyads. Data were analyzed using thematic network analysis (i.e., looking for thematic ties to established theory, as well as emerging themes). Prior research has focused on flow as a personally experienced phenomenon arising due to constructs that are largely self-controlled (e.g., loss of self-consciousness, merging of action and awareness, autotelic nature, centering of attention, feeling in control). Findings of this study, based on the triadic reciprocal determinism model, showed support for a more expansive model for flow in elite sport dyads, including behavioral, personal, and environmental influences, particularly in the area of trust. Based on findings of this study, recommendations are made for further research, including the necessity for sports flow research to move to a more applied focus using social cognitive theory. Implications of this line of research include uncovering the method by which an elite coach might create an environment in which flow experiences and improved performance outcomes might ideally occur for the athlete.

Mutations of three genes encoding amyloid precursor protein (APP), presenilin-1 (PSEN1), and presenilin-2 (PSEN2) have been shown to reliably result in familial early-onset Alzheimer's disease (FAD); a rare, but catastrophic, subtype of Alzheimer's disease (AD) marked by symptom emergence before age 65 as well as accelerated cognitive deterioration. The current study represents the first known meta-analysis on the association of APP, PSEN1 or PSEN2 on neurocognitive variables. A total of 278 FAD mutation-carriers (FAD-MC) and 284 cognitively healthy non-mutation-carriers (NC) across 10 independent investigations meeting inclusion criteria were chosen for the current meta-analysis (random effects design). Findings revealed an overarching trend of poorer performance by FAD-MC individuals compared to NC individuals across the majority of cognitive domains identified. Significant differences in effect sizes suggested FAD-MC individuals exhibited worse performance on measures of attention, explicit memory, fluency, primary memory, verbal, and visuospatial functioning. Findings indicative of differential sensitivity to cognitive domain impairments across FAD-MC and NC groups inform neuropsychological descriptions of individuals in preclinical phases of FAD.

The present study evaluated olfactory and cognitive abilities of the Tg6799 (also called 5xFAD) strain of Alzheimer’s disease (AD) model mice of two different age groups (2-3 and 8-10 months of age), and one group of healthy control mice (9-10 months). Employment of an operant conditioning paradigm using an automated olfactometer, an olfactory habituation/dishabituation test and a spatial learning test with non olfactory cues resulted in data showing that the 5xFAD mice develop olfactory impairments already at 2-3 months of age. The impairments consisted in a robust impairment in olfactory sensitivity, decreased responsiveness to novel odors and an inability to discriminate between enantiomeric odor molecules in the 5xFAD mice compared to control mice. Spatial learning deficits were also detected at this age, suggesting that cognitive functions were also affected. No differences in magnitude of the olfactory or spatial learning impairments could be detected between the age groups of model mice tested. Histological examination of development and presence of amyloid β (Aβ) plaques in the brains showed that plaques develop mainly between the ages of 3 and 8 months. This indicates that soluble Aβ rather than the formation of plaques might be responsible for the olfactory impairment and spatial learning impairments found. By 10 months of age plaque load of the 5xFAD mice was massive. The results of the present study clearly show that the 5xFAD strain might be suitable for research on human AD with regard to the early onset of olfactory impairments.

A doença de Alzheimer (DA) é uma doença neurodegenerativa caracterizada pelo declínio progressivo da memória e de outras funções cognitivas, acometendo, sobretudo, indivíduos idosos. A anormalidade do metabolismo da proteína precursora do amilóide (APP) e a hiperfosforilação da proteína TAU são processos celulares característicos desta doença. A enzima glicogênio sintase quinase 3B (GSK3B) é altamente expressa no sistema nervoso central e apresenta grande importância na regulação da plasticidade neuronal e também nos mecanismos de sobrevivência celular. Estudos têm associado a GSK3B aos mecanismos que levam à formação das placas senis e dos emaranhados neurofibrilares na DA. Diante da dificuldade para se estabelecer com precisão o diagnóstico clínico da DA, sobretudo nas fases iniciais da doença, a identificação de biomarcadores se torna particularmente importante, principalmente em tecidos periféricos. Este trabalho avaliou, por meio de dois preparos distintos, dois possíveis candidatos a marcadores bioquímicos para a DA. Em plaquetas de pacientes com DA, comprometimento cognitivo leve (CCL) e idosos saudáveis, determinamos: (1) a razão de APP (APPr), que consiste na proporção entre fragmentos de 130kDa e 110kDa da APP; e (2) a expressão das formas fosforilada (fosfo-GSK3B) e total (total-GSK3B) da enzima GSK3B, possibilitando o cálculo da razão de GSK3B (fosfo-GSK3B/total-GSK3B). Ambas as razões foram avaliadas por Western Blot utilizando anticorpos específicos. Não observamos diferença estatisticamente significante nos valores de APPr entre os três grupos estudados (p=0,847). Para o cálculo da razão de GSK3B, foram necessárias adaptações do protocolo de preparo e análise de plaquetas, prevenindo a ativação plaquetária durante o procedimento, bem como a degradação do substrato pela ação de proteases e fosfatases presentes nesta matriz biológica; deste modo foram encontradas diferenças estatisticamente significantes entre os grupos nas médias de GSK3B total e da razão de GSK3B (p=0,05 e p=0,06 respectivamente). Não foi encontrada correlação entre a razão de APP e a razão de GSK3B. Contudo, a razão de GSK3B mostrou correlação com o desempenho em testes de memória, segundo o escore na bateria cognitiva CAMCOG. Estes resultados sugerem que a razão de GSK3B em plaquetas sinaliza algumas alterações biológicas que ocorrem na progressão do CCL para a demência na DA
Alzheimer\'s disease (AD) is a neurodegenerative disease characterized by progressive decline of memory and other cognitive functions, affecting mainly elderly. The abnormal metabolism of amyloid precursor protein (APP) and protein TAU hyperphosphorylation are cellular hallmarks of this disease. Glycogen synthase kinase 3B (GSK3B) is an enzyme highly expressed in the central nervous system and of great importance in the regulation of neuronal plasticity and also the mechanisms of cell survival. Studies have associated GSK3B with the mechanisms that lead to the formation of senile plaques and neurofibrillary tangles in AD. Given the difficulty to establish the precise clinical diagnosis of AD, especially in the early stages of the disease, identification of biomarkers is particularly important, especially in peripheral tissues. This work evaluated two candidate biochemical markers for AD, using two different preparations. We investigated the ratio between 130kDa and 110kDa APP fragments (APPr) and between phosphorylated and total GSK3B (phospho-GSK3B / total-GSK3B) in platelets of patients with AD and mild cognitive impairment (MCI), comparing their results with those from healthy older adults (controls). The expression of APP fragments and GSK3B was assessed by Western blot using specific antibodies. No statistically significant differences in APPr were found between the study groups (p=0.847). We found statistically significant differences in mean total GSK3B and GSK3B ratio across disgnostic groups (p=0.05 and p=0.06, respectively). APPr and GSK3B ratio were not correlated, but the latter parameter did correlate with the performance on memory tests, as shown by the CAMCOG sub-score. The present data indicate that platelet GSK3B ratio may indicate biological changes that occur in the MCI-AD continuum

Movement-related sensory suppression is an example of a motor-sensory interaction whereby sensory stimuli are perceived as less intense before and during a movement than at rest. This thesis focuses on sensory suppression of a weak electrocutaneous stimulus delivered just prior to movement onset, and develops this situation as a paradigm for studying motor-sensory interactions. In a typical experiment, subjects prepared a motor response in advance of a visual signal. They received a weak electric shock to the right hand just prior to voluntary movement. Subjects reported at the end of each trial whether they detected the shock or not. Movement-related sensory suppression was measured by comparing shock detection rates with non-movement control trials. This general paradigm was then used in a series of behavioural experiments which systematically manipulated cognitive processing prior to movement. Premovement suppression was used to investigate the cognitive precursors of movement. First, it was shown that sensory suppression occurred for actions which were prepared, but then inhibited before execution. Second, sensory suppression was combined with the classic "stop-signal" paradigm. On trials where a stop signal came too late for subjects to inhibit their movement, a brief period of release from sensory suppression was nevertheless observed, as if the movement had been cancelled. This brief independence of sensory and motor systems suggests that the balance of excitation-inhibition is set separately for each system. Third, when subjects performed pre-prepared sequences of movements, premovement sensory suppression was related only to the first movement in the sequence, and not to subsequent movements. This suggests that motor-sensory interactions are programmed at the level of individual movements, not sequences. Finally, delivery of an unexpected startling auditory stimulus produced an acceleration of sensory suppression corresponding to the well-known acceleration of motor reaction time. This finding suggests that subcortical motor circuits involved in startle may also contribute to sensory suppression. Overall, sensory suppression proved a useful tool for investigating the cognitive processes that take place prior to movement.

2013/2014
The studies presented in this thesis contribute to the growing body of knowledge regarding the relationships between domain general precursors, domain specific precursors and mathematical learning. Given the previous inconsistent results about the link between ANS acuity and mathematical abilities (i.e. Kolkman et al., 2013) we were interested in the investigation of the relation between the ANS and early mathematics abilities in preschool years. This relationship was explored by using two different approaches: in Chapter 2 the relationship between ANS and different mathematical measures, measured concurrently, were investigated; Chapter 3 examined the possibility to improve the ANS abilities in preschool children by using intensive adaptive training over a relatively short period. Moreover, the transfer effects of the training on mathematical abilities were also examined. The second aim of this dissertation concerned the potential role played by STM and WM skills in supporting domain-specific precursors of mathematics. The few studies that considered the role of WM in simple quantity comparison abilities did not provide a strong basis for any firm conclusions on such a relationship (Mussolin, Nys, Leybaert, & Content, 2012; Soltész, Szűcs, & Szűcs, 2010) since they didn’t assess all of the WM components. Chapter 2 focuses on uncovering which specific WM component is involved in non-symbolic approximate quantity comparison processing in the preschool age. Moreover, in ordered to further explore the relationship between WM abilities and ANS, Chapter 3 investigated whether training focusing on the improvement of ANS abilities produced a far-transfer effect on WM abilities. Several studies found that WM abilities are related to overall mathematical skills (Gersten et al., 2005; Jordan et al., 2006; Passolunghi & Lanfranchi, 2012), therefore Chapter 4 investigated a possible causal relationship between domain-general working memory abilities and domain-specific numerical competence through a training study during the preschool years. The third aim of this dissertation was to explore the malleability of cognitive precursors of mathematical learning. In Chapter 3, the possibility to improve ANS abilities was investigated, whereas Chapter 4 aimed to verify and compare the effects on early numerical competence of two types of training. One type of training focused on the enhancement of domain-general precursors, working memory abilities; while the other focused on the enhancement of domain-specific precursors, early numeracy abilities. In the field of intellectual disabilities, some studies suggested that WM skills of children with neurodevelopmental disorders (like Down’s syndrome) tend to be impaired and very poor compared to typically developing children of a similar mental age (Gathercole & Alloway, 2006). In Chapter 5, the efficacy of a school-based visuo-spatial WM training on STM and WM skills for two individuals with DS was examined. The main findings emerging from overall studies and limitations, future directions and implications of the research are finally discussed in Chapter 6.
Gli studi presentati in questa tesi forniscono nuovi risultati riguardo la relazione tra precursori dominio-generali e precursori dominio-specifici dell’apprendimento matematico. Le ricerche che si sono occupate di indagare la relazione tra Approximate Numer System (ANS) e abilità matematiche finora hanno prodotto risultati contrastanti (Kolkman et al., 2013). Ci siamo quindi interessati ad approfondire lo studio della relazione tra ANS e matematica in età prescolare utilizzando due diversi approcci. Nel capitolo 2 è stato indagata la relazione tra ANS e diverse abilità matematiche, misurati contemporaneamente. Nel Capitolo 3 è stata indagata la possibilità di potenziare le abilità di ANS in bambini in età prescolare, utilizzando un training intensivo per un periodo relativamente breve. Inoltre, sono stati esaminati gli effetti del training di ANS sulle abilità matematiche. Il secondo obiettivo di questa tesi è stato quello di indagare il ruolo svolto della memoria a breve termine e della memoria di lavoro nello sviluppo dei precursori dominio-specifici dell’apprendimento matematico. I pochi studi che hanno considerato la relazione tra abilità di memoria e abilità di confronto di quantità non sono giunti a conclusioni certe su tale relazione in quanto non hanno analizzato in maniera completa il ruolo svolto da ogni componente della memoria di lavoro (Mussolin, Nys, Leybaert, & Content, 2012; Soltész, Szűcs, & Szűcs, 2010). Con lo studio descritto nel Capitolo 2 abbiamo voluto indagare quale specifica componete della memoria di lavoro sia coinvolta nel processo di comparazione di quantità in età prescolare. Inoltre, per analizzare ulteriormente tale relazione nel Capitolo 3 abbiamo indagato l’effetto, sulle abilita di memoria di lavoro, di un training focalizzato sul potenziamento delle abilità di ANS. Dato che diversi studi confermano la relazione tra memoria di lavoro e abilità matematiche (Gersten et al., 2005; Jordan et al., 2006; Passolunghi & Lanfranchi, 2012), nel capitolo 4 abbiamo esaminato la possibile relazione causale tra le capacità dominio-generali di memoria di lavoro e precursori dominio-specifici (abilità matematiche precoci) tramite uno studio di training in età prescolare. Il terzo obiettivo di questa tesi è stato quello di esplorale la malleabilità dei precursori cognitivi dell’apprendimento matematico. Nel Capitolo 3 è stata indagata la possibilità di potenziare le abilità di ANS mentre nel capitolo 4 abbiamo voluto verificare l’efficacia di due diversi tipi di training sul potenziamento della abilità matematiche in età prescolare. Il primo training era focalizzato sul potenziamento della memoria di lavoro (precursore dominio-generale) mentre il secondo training era focalizzato sul potenziamento delle abilità matematiche precordi (precursore dominio-specifico). Gli studi nel campo delle disabilità intellettive, suggeriscono che le competenze di memoria di lavoro di bambini con disturbi dello sviluppo neurologico (come la sindrome di Down) tendono ad essere compromesse e molto scarsa in confronto alle abilità di memoria di bambini con sviluppo tipico ma stessa età mentale (Gathercole e Alloway, 2006). Nel capitolo 5, è stata indagata l'efficacia di un training di memoria di lavoro visuo-spaziale sulle abilità di memoria a breve termine e di memoria di lavoro di due persone con sindrome di Down. I principali risultati della tesi, le direzioni future e le implicazioni delle ricerche sono state discusse nel Capitolo 6.
XXVII Ciclo
1987

This thesis is an examination of language and number in two atypically developing groups, Williams Syndrome (WS) and Down's Syndrome (DS). These groups were chosen because their cognitive profiles in adulthood differ significantly. It is already known that language is a relative strength in WS but that it is poorer than non-verbal ability in DS. The precursors to both language and number ability were studied in 24-36 month old infants and performance at this stage was compared with that in the steady state, by testing older children and adults, aged 9-35 years. Similar age-appropriate tests were used with both groups so that performance in the steady state could be compared with that in infancy. Specific subdomains of language and number were assessed to investigate whether the pattern seen in the adult steady state was also present in infancy, or whether the mature phenotype is a product of the different developmental trajectories followed by each group. The overall cognitive profile of infants with WS and DS did not differ significantly, despite clear distinctions between the adult profiles. However, their performance on number and language tasks did differ in infancy. While in adulthood WS performance on number tasks was poorer than that of DS, in infancy this pattern was reversed. For language, infants with DS exhibited a large discrepancy between productive and receptive vocabulary. A more even pattern was present for the WS group. In adulthood, vocabulary was better in WS than DS but both groups had problems with syntactic structures. Taken together these results suggest that it is not possible to derive the pattern of infant performance from the steady state in adulthood. The developmental trajectories from precursors to mature phenotype need to be thoroughly charted in atypical populations because the study of development, not just the characterisation of the endstates, is crucial.

The global economic turbulent environment, financial market instability, food security, land appropriation and natural disasters has significantly transformed the agricultural landscape over the past few decades. These negative environmental forces has changed the way in which farmers had to adapt to their approach to managing their farm businesses and change their actions taken in response to these complex challenges posed. Managerial cognition is understood to be an important lever that farmers have that can influence the growth or decline of their operations and should there be a decline in the farm business how they go about turning the decline around. Organizational turnaround is often referred to as n process dedicated to corporate renewal by saving organizations from bankruptcy and turning them into agile and sustainable businesses. Due to the limited information available on how to effectively manage these risks and to take informative actions while having no control over the external context, farmerÕs internal management perceptions and awareness are of great importance and can ultimately be the difference between financial success and failure. Although literature confirms that these factors have significant rippling effect on both farm businesses and agribusinesses, there are very little literature referring to how farmers can transform their actions taken in the agricultural context and drilling even further down to the unique South African context. In order to understand this business phenomena we need to understand how South African farmers perceive these complex contexts and how they respond to them from a managerial cognition perspective and the way this influences turnaround should they become financially distressed. The study was conducted through an exploratory qualitative approach. Insights into the factors that influence distress cognition were investigated and how this effects organizational decline and turnaround in farm businesses in South Africa. A total of 12 semi-structured interviews were conducted with agricultural experts, financial marketers and farmers who are considered successful in their farming operations. Thematic content analyses was used to analyze the data obtained throughout the interview process.
Mini Dissertation (MBA)--University of Pretoria, 2017.
za2018
Gordon Institute of Business Science (GIBS)
MBA
Unrestricted

Theory of mind refers to the ability to attribute mental states to others and to predict their behaviour based on inferences about their mental states, for example their perception, desires, or beliefs. Forty years ago, research on theory of mind originated from the question of whether or not chimpanzees (Pan troglodytes) have a theory of mind, a question that – after all this time – is still debated. In the present thesis, I investigate theory of mind and its precursors in birds of the crow family, specifically Eurasian jays (Garrulus glandarius), California scrub-jays (Aphelocoma californica), and carrion crows (Corvus corone corone). Corvids have been reported to possess theory of mind-like abilities. This qualification reflects the fact that most research on theory of mind in these birds has revolved around the ability to respond to perceptual and desire states of conspecifics, and so far has not produced evidence for or against an ability to also respond to others’ beliefs. Further, it is unclear which mechanisms could be the basis of corvids’ abilities. Thus, there are two open questions in regard to corvid theory of mind my thesis aims to address. To address these questions, first, I investigated the ability of Eurasian jays to respond to the false belief of a conspecific in a caching paradigm, where the knowledge of a conspecific observer about the accessibility of two caching sites was manipulated (Chapter 2). In Chapter 3 I explore which behavioural cues might present the basis of the jays’ ability to respond to the desire of a conspecific in a caching context. In Chapter 4, I report a study on biological motion perception in scrub-jays, a phenomenon suggested to be crucial for the detection of social agents. In Chapter 5, I assess scrub-jays’ sensitivity to gaze of a human and a conspecific. Finally, in Chapter 6, I report a study investigating the face inversion effect in carrion crows, an effect that is indicative of a ‘special’ relevance of faces. I conclude by discussing how the presented studies could help us inform our understanding of corvid theory of mind-like abilities.

The research presented in this thesis combined a number of aims. One was to investigate in detail the early typical development of individual cognitive domains including attention, literacy and numeracy, and consequently to investigate whether domain-general attentional abilities constrain the development of either literacy or numeracy skills in preschool to school-age children. A further aim was to test the development of the same cognitive processes in two groups of children with developmental disorders of known genetic origin; Down syndrome (DS) and Williams syndrome (WS). A combination of standardised tests, novel experimental paradigms, and questionnaire measures were employed in pursuit of these aims, and children were assessed both cross-sectionally and longitudinally one year later. In typically developing (TD) children, novel findings pointed to differential influences of cognitive constructs of sustained and selective attention on the one hand, and executive attention on the other, on reading and numeracy abilities longitudinally. In both of the atypically developing groups of children, novel and individual patterns of developmental relationships emerged in the domains of attention, literacy and numeracy. In addition, the investigation of cross-domain relationships between attentional abilities and literacy and numeracy skills evidenced typical patterns in DS children, but atypical patterns in WS children. These findings emphasize the importance of cross-syndrome, cross-domain, and fully developmental research to understand both typical and atypical profiles of cognitive development. Furthermore, teaching practice, early identification of difficulties, and interventions should consider the wider implications of potential constraints of broader cognitive domains, such as attention, on learning.

A Doença de Alzheimer (DA) é uma desordem neurodegenerativa progressiva que causa comprometimento cognitivo em idosos. O diagnóstico clínico da DA é complexo. Existe uma grande necessidade de técnicas capazes de detectar a doença nos estágios iniciais, tanto para auxiliar o diagnóstico quanto para monitorar a efetividade dos tratamentos disponíveis. As alterações bioquímicas da DA são resultado de processos celulares como o metabolismo da proteína precursora do amilóide (APP), fosforilação da tau, stress oxidativo, inflamação e desregulação lipídica. Até o momento não existem marcadores bioquímicos para auxiliar o diagnóstico da DA. Este trabalho avaliou três possíveis candidatos a marcadores bioquímicos para a DA. Foram investigados a razão da APP (rAPP) de 130/110 kDa, fluidez de membrana e atividade da fosfolipase A2 em plaquetas de pacientes com DA e Comprometimento Cognitivo Leve (CCL), comparando-se seus resultados com controles idosos saudáveis. A fluidez das membranas das plaquetas foi avaliada por meio da anisotropia com a sonda fluorescente DPH (Difenilhexatrieno); a comparação das razões da APP foi realizada por Western Blotting empregando o anticorpo 22C11 e a da atividade da PLA2 foi determinada por ensaio radioenzimático com substratos e concentrações de cálcio específicas para cada um dos três principais grupos da enzima. A rAPP, as atividades da sPLA2 e iPLA2 estavam significantemente reduzidas na DA quando comparadas com controles, enquanto que a cPLA2 e a fluidez de membrana não apresentaram diferenças entre os grupos. A rAPP e a iPLA2 também apresentaram diferenças significativas entre CCL e DA, além de estarem correlacionadas com os parâmetros cognitivos MEEM e CAMCOG. A rAPP também estava correlacionada com a anistropia do DPH.
Alzheimer disease (AD) is a progressive neurodegenerative disorder that causes cognitive impairment in the elderly. The clinical diagnosis of AD is complex. Thus, there is a great need for sensitive techniques to detect neurodegeneration in the early stages to asset in the diagnosis and to follow the effectiveness of therapy. The biochemical alterations in the AD brain result from cellular processes such as amyloid precursor protein (APP) metabolism, tau phosphorylation, oxidative stress, inflammation and lipid dysregulation. So far there are no biochemical markers to help the AD diagnosis. The purpose of this study was to evaluate three possible candidates to biochemical marker of AD. The APP 130/110 kDa ratio, membrane fluidity and phospholipase A2 activity in platelets of patients with AD and mild cognitive impairment (MCI) were investigated compared to their results with healthy elderly controls. The membrane fluidity of platelets was assessed by the fluorescence anisotropy of DPH (diphenyl-hexatriene); the levels of APP isoforms were evaluated by Western Blot analysis using 22C11 antibody and the PLA2 activity was measured by radio-enzymatic assay with enzyme specific substrate and calcium concentrations for each one of the three main groups of the enzyme. The APP ratio (APPr), the sPLA2 and iPLA2 activity were markedly decreased in AD in comparing with controls, whereas a cPLA2 and membrane fluidity didn\'t show any alteration between the groups evaluated. The APPr and iPLA2 also showed significant differences between MCI e AD, and were correlated with cognitive parameters MMSE and CAMCOG. The APPr was also correlated with DPH anisotropy.

Major depressive disorder (MDD) is common among college students. The disease perpetuates depressive symptoms and potentially leads to chronic depressive episodes. Existing literature has shown that students who use both cognitive and behavioral maladaptive coping skills are more prone to endure depressive symptoms and poorer academic performance. Despite these known associations, little research has examined the relationship between coping skills and self-efficacy in response to warning signs of MDD in college students. This study sought to fill the gaps in the research of MDD related to precursors, predictors, and coping mechanisms among undergraduate students in a national sample of U.S. college students. Secondary data (N = 6,713) were analyzed from the Healthy Minds Study 2012, which used the Patient Health Questionnaire-9 (PHQ-9) with a test-retest reliability. Social learning and social cognitive theories were used as the theoretical frameworks to focus on problems such as management of life activities, academic success, and maladaptive beliefs. Analyses of the data from the cross-sectional survey using multiple linear and logistic regressions indicated a statistically significant relationship between depressive symptoms and the potential predictive factors of MDD. These findings contribute positively to social change by informing the work of therapists and program developers, who may use these results to create programs that reduce depressive symptoms among undergraduates.

Social categorization based on group membership has a significant and broad influence on behaviour (Turner, Hogg, Oakes, Reicher, & Wetherell, 1987). People perceived as being of the same group, ‘in-group' members, are accorded all kinds of special treatment, such as the tendency to reward them over out-group members (Tajfel, Billig, Bundy, & Flament, 1971). At the other extreme is denigration based solely on a person's status as ‘out-group' member, sometimes even to the point of perceiving that person as less human than fellow in-group members, a phenomenon termed dehumanisation (Leyens et al., 2001). Historic examples of dehumanisation are abundant, such as the extermination of Jews in Nazi Germany. What is less well understood, however, are the cognitive processes involved in these inter-group phenomena. How can a normal human being, with fully functioning cognitive faculties, come to not only view another person as sub-human but also to act on such irrational beliefs? One cognitive ability that, according to theory, plays a pivotal role in every human social interaction is the ability to attribute mental states to others, which enables humans to construct a theory of the minds they interact with. Having a ‘theory of mind' allows an individual to interpret and predict behaviour in terms of underlying mental states (Premack & Woodruff, 1978). It is widely acknowledged that theory of mind is of fundamental importance to human social interactions (Baron-Cohen, Tager-Flusberg, & Cohen, 2000). For example, the ability to understand others' intentions and goals allows humans to participate in collaborative action with shared ends, a hallmark capacity required for human social structures such as governments and economic systems (Tomasello, Carpenter, Call, Behne, & Moll, 2005). Given the importance of theory of mind to daily human life, a critical question thus is when and how theory of mind is actually used, especially in inter-group contexts such as those previously mentioned. While the developing, abnormal, and non-human theory of mind have been thoroughly investigated, much less is known about how normal adults deploy their theory of mind in actual social situations, including in situations of inter-group conflict. The present thesis has the primary aim of understanding how group membership affects the quotidian functioning of theory of mind and the social cognitive abilities that form its foundation, representation of intentionality and more basic processes of social learning. To this end, I will examine the effects of group membership on normal adults' theory of mind usage (study 1). I will then go on to look at the deeper effects of group membership on social cognition, particularly its effect on some of the building blocks of theory of mind, representation of intentionality and basic social learning. To this end, I will first look at how intentionality is represented as a function of a person's group membership with and without social competition (studies 2 & 3), and on how perceptions of group membership and social power impact basic social learning processes (studies 4 & 5). This process will elucidate the degree to which social cognition processes, from theory of mind down to its basic cognitive roots, are affected by perceptions of group membership. A secondary goal is to generate more informed hypotheses about the nature of the cognitive mechanisms underlying group- based social phenomena, such as dehumanisation.

2012/2013
The field of mathematical learning has received in recent years increasing attention in research, clinical and educational settings. The leading research line is dedicated to the investigation of the cognitive abilities fundamental for the acquisition and application of math concepts. Among general abilities, there is a wealth of evidence in favor of the recruitment of both working memory and short-term memory, despite there is no agreement concerning the involvement of the related subcomponents. Conflicting results pertain also the role of intelligence. Even major debate concerns more specific cognitive abilities, therefore those closely related to mathematics. In particular, it has not been elucidated the involvement of basic skills entailing approximate judgments about magnitudes and identified with ANS. Moreover, it is not yet clear how the recruitment of all these abilities can vary in dependence on stage of development and level of instruction. The other research line, almost independent from the previous, is dedicated to the evaluation of constructs non-cognitive in nature, for instance affective and motivational factors but also self-perceptions, in relation to academic achievement. Mainly studied are constructs such as self-efficacy and anxiety, with particular reference to a subtype of anxiety that is specific to math. Other relevant aspects are represented by constructs such as self-concept and self-esteem, but also depression. Nevertheless, this kind of studies is usually conducted on old children, typically in those attending secondary school or college, whereas less attention is dedicated to younger students. Starting from these considerations, the purpose of the current dissertation has been that of elucidating which are the factors, both cognitive and non-cognitive, that can assume a greater relevance at the beginning of schooling, i.e., in the first grades of primary school. These factors have been inspected both separately and by trying to find a possible interrelation between them. In CHAPTER 1, the topics that are object of the present work are illustrated by delineating the state-of-the-art pertinent to each of them. CHAPTER 2 is dedicated to the description of Study 1, where a broad range of cognitive abilities including memory, intelligence and ANS has been investigated just at the beginning of formal instruction and therefore in relation to early math competence. Having proved the significant involvement of all tested skills, the consequent aim was that of exploring to which extent the same are suitable in the prediction of math performance in following grades. This investigation has represented the topic of Study 2, illustrated in CHAPTER 3. In this study, children were longitudinally followed from first to third grade, observing that the tested abilities can successfully predict future math learning, but with a leading role of working memory. Once having shed light on the involvement of cognitive abilities, a second purpose was the investigation of the possible involvement in young students of non-cognitive factors. These constructs were thus assessed in Study 3, reported in CHAPTER 4. The sample was represented by second graders and more relevant aspects resulted to be self-efficacy and general anxiety. Contrary to expectations, anxiety specific to math appeared be non-significantly related to math performance. For this reason, Study 4, described in CHAPTER 5, was dedicated to an extensive evaluation of this constructs in third graders, in order to inspect when it could become relevant. Results suggested the association with math performance to establish in third grade, with particular impact of anxiety related to learning math rather than that associated to the math testing condition. The main findings emerging from overall studies and limitations, future directions and implications of the research are finally discussed in CHAPTER 6.
Negli ultimi anni, lo studio dell’apprendimento della matematica ha iniziato a ricevere crescente attenzione nel campo della ricerca, ma anche in quello clinico ed educativo. Maggiore interesse è dedicato allo studio delle abilità cognitive che sottostanno all’apprendimento e all’applicazione dei concetti matematici. Tra le abilità a carattere generale, in letteratura esiste un forte consenso sul ruolo cruciale della memoria, sia di lavoro che a breve termine, nonostante non sia del tutto chiarito il coinvolgimento relativo delle varie componenti della stessa. Dibattito sussiste anche in merito al ruolo dell’intelligenza. Ancora maggiori divergenze permangono in merito al ruolo di abilità più specifiche, ovvero strettamente pertinenti alla matematica. In particolare non c’è accordo sul ruolo di abilità molto di base, indicate come ANS, e che consistono nel fornire giudizi approssimati in merito a grandezze e quantità. In aggiunta, non è chiaro il coinvolgimento relativo delle sopraccitate abilità in relazione a determinati stadi dello sviluppo o livelli di istruzione. Il secondo filone di ricerca, perlopiù indipendente dal precedente, è rappresentato dalla valutazione di aspetti prettamente non-cognitivi, quali quelli affettivi e motivazionali, ma anche percezioni che gli individui formano in merito a se stessi e alle proprie capacità. I costrutti maggiormente indagati sono quelli dell’auto-efficacia e dell’ansia, sia generale che specifica per la matematica. Altri aspetti rilevanti sono rappresentati dal concetto di sé, dall’autostima e dalla depressione. Questi fattori sono tuttavia tipicamente valutati in studenti a partire dalla scuola secondaria, mentre minore attenzione viene dedicata a quelli frequentanti i primi anni del percorso scolastico. A partire da queste considerazioni, l’obiettivo primario del presente lavoro di tesi è consistito nella valutazione di quali fattori, sia cognitivi che non, hanno una maggiore rilevanza nell’ambito della prestazione matematica all’inizio della scolarità, più precisamente nelle prime classi della scuola primaria. Si è voluto valutare questi fattori sia indipendentemente, sia esplorandone la possibile influenza reciproca. Il CAPITOLO 1 è quindi dedicato alla discussione degli argomenti trattati in modo da fornire una panoramica sullo stato dell’arte attuale in merito alle ricerche condotte e ai relativi risultati. Il CAPITOLO 2 è centrato sulla descrizione dello Studio 1, in cui è stato testato un ampio spettro di abilità cognitive quali memoria, intelligenza e ANS, in bambini appena avviati all’istruzione formale e pertanto valutando il ruolo di queste abilità in relazione ad abilità matematiche precoci, prettamente informali. Verificato il coinvolgimento significativo di abilità tanto generali quanto specifiche all’inizio della scolarità, l’obiettivo conseguente è stato quello di verificare in che modo tali abilità siano in grado di predire l’apprendimento matematico negli anni successivi della scuola primaria. Questo obiettivo ha caratterizzato lo Studio 2, descritto nel CAPITOLO 3. Un campione di bambini è stato seguito longitudinalmente dalla classe prima alla classe terza, riscontrando che tutte le abilità indagate hanno un significativo impatto anche sull’apprendimento formale della matematica, ma con un ruolo primario assunto dalla memoria di lavoro. Una volta delineato il quadro delle abilità cognitive cruciali nei primi anni scuola, la volontà è stata quello di esplorare se anche costrutti non-cognitivi possano avere un impatto significativo. Lo Studio 3, illustrato nel CAPITOLO 4, si è quindi focalizzato anche sulla valutazione di questi aspetti in bambini di classe seconda, riscontrando un diretto coinvolgimento di auto-efficacia ed ansia generale. Contrariamente alle aspettative, l’ansia specifica per la matematica non è risultata avere alcun legame significativo con la prestazione matematica. A partire da questo risultato, l’obiettivo dello Studio 4, riportato nel CAPITOLO 5, è consistito nella valutazione più approfondita di questo costrutto in bambini di classe terza, in modo da esplorare quando lo stesso possa diventare rilevante ai fini della prestazione matematica. I risultati hanno dimostrato un ruolo significativo a questo livello, in particolare per quanto concerne l’ansia da apprendimento, piuttosto che di valutazione, della disciplina. Il CAPITOLO 6 è quindi dedicato alla discussione generale dell’elaborato in cui sono riassunti i principali risultati emersi e discusse le limitazioni, prospettive future ed implicazioni pratiche della ricerca.
XXVI Ciclo
1986

Introdução: Doença arterial obstrutiva periférica é uma síndrome na qual placa aterosclerótica causa obstrução de artérias dos membros inferiores. Entre os fatores de risco estão tabagismo, dislipidemia, diabetes e hipertensão arterial. Embora esta última seja certamente o fator de risco mais freqüente, prevalência de DAOP nessa população não foi adequadamente avaliada. Apenas cerca de 10% dos indivíduos acometidos são sintomáticos e, portanto, diagnóstico exige exame complementar; o índice tornozelo braquial (ITB) é obtido calculando a razão entre pressão arterial aferida na artéria pediosa ou na tibial posterior sobre a pressão na artéria braquial, e é considerado padrão ouro para diagnóstico não invasivo. Valores abaixo de 0,9 são considerados para o diagnóstico de DAOP. Há grande associação entre baixo ITB e incidência de eventos cardiovasculares. Buscando identificar indivíduos que obteriam maior benefício na prevenção de eventos, ITB foi proposto como possível re-estratificador para pacientes de risco cardiovascular intermediário. Decisão sobre inclusão de exame na rotina de avaliação de pacientes de uma população tão ampla deve considerar também aspecto econômico; foram publicadas análises sobre uso de estatina em prevenção primária, e também estudo considerando Proteína C Reativa de alta sensibilidade como exame para re-estratificação, porém todas em cenário internacional. Até o momento não há avaliação econômica sobre o ITB como re-estratificador de risco, em cenário internacional ou nacional. Para a revisão da literatura necessária optou-se por calcular sumário de efeitos utilizando software amplamente disponível, e evidenciou-se que um guia para tal análise não estava presente na literatura. Ainda, identificou-se dificuldade em visualizar graficamente dados descritivos de estudos observacionais. Métodos: Foi conduzido estudo transversal em ambulatório de referência em hipertensão. Uma amostra aleatória de pacientes teve ITB aferido por dois examinadores treinados. Dois métodos de cálculo do ITB foram utilizados, considerando-se a maior pressão e a menor pressão do tornozelo (respectivamente, HAP e LAP). Um subgrupo de participantes teve ITB aferido por dois examinadores para avaliar concordância. Para análise econômica, desenhou-se estudo de custo-utilidade da perspectiva do sistema público de saúde. Construiu-se um modelo de Markov seguindo uma coorte teórica de pacientes de risco cardiovascular intermediário, comparando as estratégias de cuidado usual (sem uso de estatinas e sem rastreio), rastreio por ITB (e conseqüente prescrição de estatinas para pacientes com ITB baixo), e estatinas para todos os pacientes (sem rastreio). Os custos foram baseados em estimativas do sistema público de saúde e outros parâmetros foram baseados em uma ampla revisão da literatura. Resultados: Orientação passo a passo para condução de meta-análise de estudos observacionais utilizando o Microsoft Excel foi descrita, e foi também desenvolvida metodologia para geração de gráficos Forest Plot nesse software. Planilhas com as fórmulas e modelo de gráfico foram disponibilizadas para download em periódico de acesso livre. No estudo transversal, 222 pacientes foram incluídos (85,6% da amostra inicial). A maioria dos participantes era do sexo feminino (71,7%), com idade média de 64 ± 11,2 anos. Prevalência de DAOP foi de 14,9% (10,81% - 18,99%), considerando HAP e 33,8% (28,31% - 39,29%), considerando LAP. Concordância entre examinadores foi satisfatória por todas as avaliações. Entre os pacientes (38%) que não recebiam estatinas, 8,2% teriam mudança de prescrição após aferição de ITB por HAP (3% da amostra inicial). No entanto, utilizando o método de LAP, até 31,8% dos que não utilizavam hipolipemiantes mudariam de prescrição (12% da amostra original). No modelo de custo-utilidade desenvolvido, a prescrição de estatinas para todos os pacientes de risco intermediário dominou as demais estratégias no caso base, retornando mais utilidades e menos custos. O modelo foi sensível aos efeitos adversos das estatinas, e um decréscimo de 1% na qualidade de vida dos pacientes em uso de estatinas anularia benefícios de redução de eventos. Em um cenário alternativo considerando os custos de compra privada de estatinas, cuidado usual seria a alternativa menos dispendiosa, e os ICERs para rastreio com ITB e para prescrição de estatinas para todos os pacientes seriam 72.317 e 83.325 R$ / QALY para os homens e 47.496 e 77.721 R$ / QALY para as mulheres. Conclusões Principais: Identificamos que DAOP é prevalente entre pacientes hipertensos, particularmente se considerado cálculo por menor pressão distal. Entre os principais achados da tese, vê-seque aferição de ITB como exame de rastreio nessa população pode acarretar mudança no tratamento farmacológico de contingente significativo de pacientes. Apesar disso, os resultados da análise econômica indicam que estratégia que prescreva estatinas para toda população de risco cardiovascular intermediário deve prover mais utilidades e menor custo, desde que seja considerada como medicamento com pouco impacto deletério na qualidade de vida dos pacientes e de muito baixo custo. Em cenários alternativos onde essas premissas não se mantenham, ITB como exame de rastreio poderia constituir alternativa com razão de custo-efetividade incremental dentro do aceitável para padrões brasileiros.
Thesis Title: Screening for Peripheral Arterial Disease: Impact on Pharmacological treatment of Hypertensive Patients and Cost-Effectiveness Analysis in Cardiovascular Risk Re-Stratification Introduction: Peripheral arterial disease (PAD) is a syndrome in which atherosclerotic plaque causes obstruction in the arteries of the lower limbs. Smoking, dyslipidemia, diabetes and hypertension are among the risk factors. While the latter is certainly the most frequent risk factor, the prevalence of PAD in this population has not been adequately evaluated. Only about 10% of affected individuals are symptomatic, and therefore diagnosis requires further examination. The ankle brachial index (ABI), which is the ratio of blood pressure measured in the dorsalis pedis or posterior tibial artey to the pressure measured on the brachial artery, is considered the gold standard for noninvasive diagnosis. Values below 0.9 are considered abnormal. There is a strong association between low ABI and incidence of cardiovascular events. In an effort to identify individuals who would more likely benefit from primary prevention, the ABI has been proposed as a tool for re-stratifying patients at intermediate cardiovascular risk. A decision regarding inclusion of this test in routine evaluation of such a large population must consider economic consequences; analyses of statin use on primary prevention have been published, and a study evaluating screening with high-sensitivity C-Reactive Protein has also been published, but only considering an international scenario. To date, no economic assessment regarding the ABI has been conducted, neither abroad nor at national level. During literature review, we identified that guides for meta-analyzing data using widely available software were not available. We also encountered difficulty in graphically displaying descriptive data from observational studies. Methods: We conducted a cross-sectional study in a reference hypertension outpatient clinic. A random sample of patients was selected and had ABI measured by two trained examiners. Two methods of calculating the ABI were used, considering the higher (HAP) and lower (LAP) ankle pressures. In a subset of patients the ABI was performed by both examiners to assess agreement. For the economic assessment, we conducted a cost-utility analysis from the public health system perspective. Markov model was designed to follow theoretical cohorts at intermediate-risk for cardiovascular events, comparing the strategies of usual care (no statins and no screening), ABI screening (and prescription of statins for patients with low ABI), and statins for all patients (without screening). Costs were based in public health system estimates and other parameters were based on a broad literature review. Results: A step by step description on performing a meta-analysis on Microsoft Excel was described, and a methodology for generating Forest Plots using this software was also developed. Spreadsheets with the formulas and a chart model was made available for download on an open access journal. On the cross-sectional study 222 patients were included (85.6% of the original sample). Most participants were females (71.7%), with a mean age of 64 ± 11.2. Prevalence of PAD was 14.9% (10.81% – 18.99%) considering the HAP and 33.8% (28.31% – 39.29%) considering LAP. Agreement between examiners was satisfactory by all assessments. Among the 38% of patients not receiving lipid therapy, 8.2% would change prescription after ABI screening by HAP (3% of the original sample). However, using the LAP method, up to 31.8% of those not using lipid lowering therapy would change prescription (12% of the original sample). On the cost-utility analysis, prescribing statins for all intermediate risk patients dominated the other strategies on the base case, yielding more utilities and fewer costs. The model was sensible to statin adverse effects, with a 1% decrement in quality of life negating statins benefits. In an alternative scenario considering costs for over the counter statins purchase, no screening would be the least costly alternative, and the ICERS for ABI screening and statins for all patients would be 72,317 and 83,325 R$/QALY for men and 47,496 and 77,721 R$/QALY for women. Main Conclusions: We identified that PAD is prevalent among hypertensive patients, particularly if the lower ankle pressure is considered. Among the main findings of this thesis, we conclude that measurement of ABI as a screening test in this population may lead to change in the pharmacological treatment of a significant number of patients. Nevertheless, the results of the economic analysis indicate that a strategy prescribing statins to all intermediate cardiovascular risk population would provide more utilities at a lower cost, once statins are considered a drug with little deleterious impact on quality of life and of a very low cost . In alternative scenarios where these assumptions may not hold, the incremental cost-effectiveness ratio of an ABI screening strategy could be within the acceptable standards for Brazil.

Les technologies émergentes de l’hydrogène énergie s’intégreront dans des systèmes énergétiques futurs, qui n’existeront pas avant plusieurs années. Dans ce cas, l’analyse des situations actuelles d’usages est utile, mais aussi insuffisante, car elle ne permet pas d’identifier les besoins des utilisateurs qui seraient en rupture avec les usages actuels. L’ergonomie doit donc évoluer pour identifier prématurément les besoins futurs qui pourraient être associés à ces systèmes qui n’existent pas encore. Néanmoins, l’anticipation de besoins futurs est difficile car les utilisateurs ont une représentation pauvre du futur et des artefacts et activités futurs. De plus, les concepteurs se réfèrent à une représentation hypothétique des utilisateurs et ils se basent sur l’analyse de situations présentes pour inférer des besoins futurs. La définition d’idées d’artefacts futurs est aussi problématique car les utilisateurs n’ont pas les connaissances suffisantes et les concepteurs se focalisent sur les aspects techniques, ont des difficultés à intégrer les utilisateurs et ont tendance à se restreindre à leurs connaissances actuelles des utilisateurs et des artefacts. Cette thèse vise à identifier des méthodes qui soutiennent une idéation centrée sur les utilisateurs futurs. Pour répondre à cet objectif, cette recherche propose d’évaluer et d’appliquer à l’hydrogène énergie, une méthodologie qui repose sur (1) l’implication d’utilisateurs précurseurs dans le cadre d’entretiens d’anticipation des besoins et (2) sur le recours à la méthode du persona prospectif avec des experts du domaine. Cette thèse s’articule autour de trois études. L’étude 1 est une méta-analyse de la littérature scientifique sur l’hydrogène énergie. Cette étude a montré que l’usage d’hydrogène énergie pour l’habitat est peu étudié alors qu’il constitue une application prometteuse et que la prise en compte des utilisateurs à cet égard est insuffisante. L’étude 2 porte sur l’analyse d’entretiens d’anticipation des besoins. Les résultats indiquent que les utilisateurs précurseurs permettent d’identifier des besoins futurs qu’ils expérimentent actuellement et qu’ils ont une représentation riche du domaine qui leur permet d’imaginer de nouveaux besoins futurs. L’étude 3 s’attache à l’analyse de séances de créativité réalisées avec un persona ordinaire, un persona prospectif ou sans persona. Les résultats indiquent que le persona prospectif favorise la production d’idées nouvelles et faisables
Emerging hydrogen energy technologies will be integrated into future energy systems, which will not exist for several years. In this case, the analysis of current situations of uses is beneficial, but also insufficient, as it does not allow the identification of user needs that would be at odds with current uses. Ergonomics must therefore evolve to identify at an early stage the future needs that could be associated with these systems that do not yet exist. Nevertheless, anticipating future needs is difficult because users have a poor representation of the future and of future artefacts and activities. Moreover, designers have a representation of users that does not necessarily correspond to reality and they rely on the analysis of present situations to infer future needs. The definition of future artefacts’ ideas is also challenging because users do not have sufficient knowledge and designers focus on technical aspects, have difficulty integrating users and tend to limit themselves to their current knowledge of users and artefacts. This thesis aims at identifying methods that support a future user-centred ideation in the future fuzzy front end design phase. To meet this objective, this thesis proposes to evaluate and apply to hydrogen energy, a future fuzzy front end design phase methodology based on (1) the involvement of precursory users in needs anticipation interviews and (2) the use of the prospective persona method by experts. This thesis is based on three studies. Study 1 is a meta-analysis of the scientific literature on hydrogen energy. This study showed that the use of hydrogen energy for housing is little studied, even though it is a promising application, and that the users are insufficiently considered in this matter. Study 2 concerns the analysis of needs anticipation interviews on the theme of energy for housing. The results indicate that precursory users provide an opportunity to identify future needs that they are experiencing at present and that they have a rich representation of the field that enables them to imagine new future needs. Study 3 focuses on the analysis of creativity sessions carried out with ordinary persona, prospective persona or without persona. The results indicate that prospective persona promotes the generation of new and feasible artifact ideas

The purpose of this research was to develop and evaluate a 5-week readiness for change precursor to group cognitive-behavioral therapy for individuals with eating disorders. Group content was based on the theories of the Transtheoretical Model of Change and Motivational Interviewing, and also included an experiential pretraining component. Forty-six medically stable individuals with anorexia nervosa, bulimia nervosa or eating disorder not otherwise specified (EDNOS) were recruited from the Adult Eating Disorders Program at the Health Sciences Centre in Winnipeg, Canada. Participants completed measures of readiness for change, eating disorder symptomatology, and treatment outcome at three time points: pre- and post-readiness precursor, and post-cognitive-behavioral group. One-way repeated measures analysis of variance, regression analysis, and Cochran’s Q analysis were used to investigate hypotheses. Results revealed that participants’ readiness for change increased significantly following the readiness group. However, despite changes in readiness, stage of change awareness and cognitive-behavioral treatment drop-out rates were not significantly improved. In was concluded that motivational interventions appear to be an effective way to increase readiness for change in the eating disorders, however more research is needed to determine whether increases in readiness have a significant impact on treatment outcome.

The uniquely human mathematical mind sets us apart from all other animals. Although humans typically think about number symbolically, we also possess nonverbal representations of quantity that are present at birth and shared with many other animal species. These primitive numerical representations are thought to arise from an evolutionarily ancient system termed the Approximate Number System (ANS). The present dissertation aims to determine how these preverbal representations of quantity may serve as the foundation for more complex quantitative reasoning abilities. To this end, the five studies contained herein investigate the relations between representations of number, representations of other magnitude dimensions, and symbolic math proficiency in infants, children, and adults. The first empirical study, described in Chapter 2, investigated whether infants engage the ANS to represent the full range of natural numbers. The study presented in Chapter 3 compared infants' acuity for detecting changes in contour length to their acuity for detecting changes in number to assess whether representations of continuous quantities are primary to representations of number in infancy. The study presented in Chapter 4 compared individual differences in acuity for number, line length, and brightness in children and adults to determine how the relations between these magnitudes may change over development. Chapter 5 contains a longitudinal study investigating the relation between preverbal number sense in infancy and symbolic math abilities in preschool-aged children. Finally, the study presented in Chapter 6 investigated the mechanisms underlying the maturation of the number sense and determined which features of the number sense are predictive of symbolic math skill. Taken together, these findings confirm that number is a salient feature of the environment for infants and young children and suggest that approximate number representations are fundamental for the acquisition of symbolic math.

Dissertation

Στη παρούσα διατριβή παρουσιάζονται τα αποτελέσματα μιας έρευνας σχετικής με το σχεδιασμό, την εφαρμογή και την αξιολόγηση μιας διδακτικής παρέμβασης σχετικής με την οικοδόμηση της έννοιας της κατηγοριοποίησης των ζώων από παιδιά προσχολικής ηλικίας, στα πλαίσια της τυπικής και της μη τυπικής εκπαίδευσης. Η διδακτική αυτή παρέμβαση βασίζεται στις αρχές της ‘εποικοδομητικής’ προσέγγισης για τη διδασκαλία και μάθηση των φυσικών επιστημών και συμπεριλαμβάνει δραστηριότητες που λαμβάνουν χώρα τόσο στο χώρο του σχολείου όσο και σε χώρο ενός μουσείου Ζωολογίας. Με βάση τα αποτελέσματα της έρευνας παρέχονται ενδείξεις σύμφωνα με τις οποίες τα παιδιά μετά το πέρας της διδακτικής παρέμβασης είναι δυνατόν να οικοδομήσουν την έννοια της κατηγοριοποίησης των ζώων με τη χρήση μορφολογικών αντί λειτουργικών ή/και ανθρωπομορφικών κριτηρίων που συνήθως χρησιμοποιούν. Πιο συγκεκριμένα φαίνεται (α) να βελτιώνουν τις γνώσεις τους σχετικά με την αναγνώριση και ονοματοδοσία δειγμάτων ζώων που ανήκουν στις κατηγορίες ‘ερπετό’, ‘πτηνό’, ‘ψάρι’ και ‘θηλαστικό’ και (β) να αναγνωρίζουν μια κατηγορία ζώων από ένα δείγμα ζώου αναφερόμενα στα βασικά μορφολογικά χαρακτηριστικά του. Επίσης διαπιστώνεται ότι η επίσκεψη στο μουσείο ζωολογίας και οι δραστηριότητες που πραγματοποιούνται επί τόπου φαίνεται να συμβάλλουν καθοριστικά στο μετασχηματισμό και την εξέλιξη των νοητικών παραστάσεων των παιδιών για την έννοια της κατηγοριοποίησης των ζώων.
This thesis presents the results of a research concerning the design, implementation and evaluation of a teaching intervention relevant to the classification of animals within the formal and non-formal education. This teaching intervention refers to preschoolers, is based on the principles of 'constructive' approach of teaching and learning of science and includes educational activities which take place both at school and at the zoological museum. According to the findings of the research, there is indications accordance to which children after the end of the teaching intervention are able to construct the concept of classification of animals using morphological characteristics instead of function or anthropomorphic ones. More specifically, this thesis gives indications according to which children after the teaching intervention are able (a) to improve their knowledge on the recognition and denomination of specimens of animals belonging to the categories of 'reptile', 'bird', 'fish' and 'mammal' and (b) to recognize a category of animals by an animal sample based on the morphological characteristics. Finally, it is also noted that the visit to the zoological museum and the educational activities carried out in situ seems to make a significant contribution in the transformation and progress of cognitive representations of children for the concept of classifying animals.

This dissertation research focuses on assessing student behavior, academic emotions, and knowledge within a middle school online learning environment, and analyzing potential effects on students’ interests and choices related to decisions about going to college. Using students’ longitudinal data ranging from their middle school, to high school, to postsecondary years, this dissertation uses quantitative methodologies to investigate antecedents to college attendance that occur as early as middle school. The dissertation asks whether student behavior, academic emotions, and learning as early as middle school can be predictive of college attendance years later. This is investigated by developing predictive and structural models of said outcomes, using assessments of learning, emotions and engagement from student interaction data from an online learning environment they used in their middle school curriculum. The same middle school factors are also assessed with self-report measures of course choices, interests in college majors and careers formed when they were in high school. The dissertation then evaluates how student choices and interests in high school can mediate between the educational experiences students have during middle school and their eventual college attendance, to give a fuller illustration of the cognitive and non-cognitive mechanisms that students may experience throughout varied periods in school. Such understanding may provide educators with actionable information about a students’ in-depth experiences and trajectories within the college pipeline.

Indiana University-Purdue University Indianapolis (IUPUI)
Alzheimer disease (AD) results, in part, from the excess accumulation of the amyloid-β peptide (Aβ) as neuritic plaques in the brain. The short Aβ peptide is derived from a large transmembrane precursor protein, APP. Two different proteolytic enzymes, BACE1 and the gamma-secretase complex, are responsible for cleaving Aβ peptide from APP through an intricate processing pathway. Dysregulation of APP and BACE1 levels leading to excess Aβ deposition has been implicated in various forms of AD. Thus, a major goal in this dissertation was to discover novel regulatory pathways that control APP and BACE1 expression as a means to identify novel drug targets central to the Aβ-generating process. MicroRNAs (miRNA) are short, non-coding RNAs that act as post-transcriptional regulators of gene expression through specific interactions with target mRNAs. Global analyses predict that over sixty percent of human transcripts contain evolutionarily conserved miRNA target sites. Therefore, the specific hypothesis tested was that miRNA are relevant regulators of APP and BACE1 expression. In this work, several specific miRNA were identified that regulate APP protein expression (miR-101, miR-153 and miR-346) or BACE1 expression (miR-339-5p). These miRNAs mediated their post-transcriptional effects via interactions with specific target sites in the APP and BACE1 transcripts. Importantly, these miRNA also altered secretion of Aβ peptides in primary human fetal brain cultures. Surprisingly, miR-346 stimulated APP expression via target sites in the APP 5’-UTR. The mechanism of this effect appears to involve other RNA-binding proteins that bind to the APP 5’-UTR. Expression analyses demonstrated that these miRNAs are expressed to varying degrees in the human brain. Notably, miR-101, miR-153 and miR-339-5p are dysregulated in the AD brain at various stages of the disease. The work in this dissertation supports the hypothesis that miRNAs are important regulators of APP and BACE1 expression and are capable of altering Aβ homeostasis. Therefore, these miRNA may possibly serve as novel therapeutic targets for AD.