Orientador: Adrian Oscar Dongo Montoya / Resumo: Esta pesquisa trata do desenvolvimento da noção de transmissão mediata do movimento na criança segundo a Epistemologia Genética. Tal pesquisa contou com a réplica de uma situação experimental desenvolvida por Piaget e seus colaboradores com crianças genebrinas. (Piaget, 1972) Foram pesquisados cento e sete sujeitos com idade entre quatro e treze anos. A situação experimental envolve a problemática da transmissão mediata e solicita do sujeito a explicação causal. Assim, o desenvolvimento da noção de transmissão mediata foi pesquisado nos limites da noção de causalidade. Os resultados da pesquisa empírica revelam que foram encontrados os mesmos níveis de desenvolvimento que Piaget encontrou com crianças genebrinas, mesmo passados quase trinta anos. Isto mostra que a noção de transmissão mediata do movimento se refere a uma construção operatória que se dá a partir da relação entre o sujeito e o objeto caracterizando-se por uma gradual descentração e espacialização resultante das coordenações. Para se chegar à noção de transmissão mediata do movimento é preciso que o sujeito construa um sistema operatório, componível e reversível. Porém, os resultados gerais, indicam uma progressão (do número de sujeitos segundo a sucessão das faixas etárias) diferente da encontrada por Piaget em relação aos níveis de desenvolvimento da noção de transmissão mediata do movimento, indicando uma dificuldade na passagem para a transitividade operatória. / Abstract: This research is about the development of the notion of mediate transmission of the movement on children according to the Genetic Epistemology. The research took under consideration the reply of a experimental situation with genevan children developed by Piaget and his collaborators. (Piaget, 1972) A hundred and seven people, between four and thirteen years old , have been researched. The experimental situation involves the proposition of mediate transmission and request to the person for a casual explanation. Therefore, the development of the notion of mediate transmission has been researched between the limits of the causality notion. The results of the empiric research reveal that the same levels of the development that Piaget had found with de genevan children, were also found almost thirty years later. It shows that the notion of the mediate transmission of movement refers to an operatory process that derives from the relationship between the subject and the objet and it is distinguished by a gradual descentralization and spacing that are the results of the coordination. To achieve the notion of mediate transmission it's necessary that the person builds na operatory system, composable and reversible. However, the general results indicate a the progress of the levels, according to the succession of the age diferent that founded by Piaget, indicating a difficulty on the passage to the operatory transitivity. / Mestre

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In a previous study on maize (Zea mays, L.) several quantitative trait loci (QTL) showing high dominance-additive ratio for agronomic traits were identified in a population of recombinant inbred lines derived from B73 × H99. For four of these mapped QTL, namely 3.05, 4.10, 7.03 and 10.03 according to their chromosome and bin position, families of near-isogenic lines (NILs) were developed, i.e., couples of homozygous lines nearly identical except for the QTL region that is homozygote either for the allele provided by B73 or by H99. For two of these QTL (3.05 and 4.10) the NILs families were produced in two different genetic backgrounds. The present research was conducted in order to: (i) characterize these QTL by estimating additive and dominance effects; (ii) investigate if these effects can be affected by genetic background, inbreeding level and environmental growing conditions (low vs. high plant density). The six NILs’ families were tested across three years and in three Experiments at different inbreeding levels as NILs per se and their reciprocal crosses (Experiment 1), NILs crossed to related inbreds B73 and H99 (Experiment 2) and NILs crossed to four unrelated inbreds (Experiment 3). Experiment 2 was conducted at two plant densities (4.5 and 9.0 plants m-2). Results of Experiments 1 and 2 confirmed previous findings as to QTL effects, with dominance-additive ratio superior to 1 for several traits, especially for grain yield per plant and its component traits; as a tendency, dominance effects were more pronounced in Experiment 1. The QTL effects were also confirmed in Experiment 3. The interactions involving QTL effects, families and plant density were generally negligible, suggesting a certain stability of the QTL. Results emphasize the importance of dominance effects for these QTL, suggesting that they might deserve further studies, using NILs’ families and their crosses as base materials.

L’agricoltura si trova ad affrontare una diminuzione della disponibilità d’acqua ed una crescente domanda della produzione di cereali per scopi alimentari. Sono perciò necessarie strategie di coltivazione innovative per migliorare la produttività e nuovi genotipi migliorati nell'efficienza dell’uso delle risorse in condizioni di siccità. Questi rappresentano gli obietti principali del progetto “DROPS” (Drought tolerant yielding Plants) all’interno del quale ha avuto luogo il mio progetto di Dottorato. La mia attività di ricerca è stata svolta come segue: 1. Caratterizzazione molecolare di un panel di188 accessioni di frumento duro con marcatori SSR e DaRT; 2. Esperimenti in serra su 100 accessioni del panel per valutare la Water-Use Efficiency (WUE) in sei repliche secondo un Alpha Lattice design; 3. Prove sul campo, effettuate secondo un Alpha Lattice design, in due stagioni di crescita: a. 2010/11, valutazione di 100 accessioni presso l’Azienda sperimentale dell'Università di Cadriano (BO); b. 2011/12, valutazione del panel completo in 3 ambienti, con due diversi regimi irrigui In entrambi gli anni, abbiamo valutato caratteri agronomici correlati con il ciclo di sviluppo, la resa di granella e sue componenti, nonché diversi fattori ambientali e del suolo. Per quanto riguarda WUE, abbiamo trovato differenze altamente significative tra accessioni; inoltre, cinque accessioni hanno mostrato elevati valori di WUE e cinque accessioni valori molto bassi di WUE in tutte e sei le repliche. Gli esperimenti di campo nelle stagioni 2011 e 2012 hanno evidenziato differenze altamente significative tra le accessioni del panel per la maggior parte dei caratteri analizzati, confermando inoltre che il panel di fiorisce entro una settimana. L'esperimento del secondo anno ci ha permesso osservare un significativa interazione Genotipo X Ambiente. Questi risultati saranno integrati con ulteriori analisi QTL, per identificare regioni cromosomiche coinvolte nel controllo genetico dei caratteri di interesse e verificare la stabilità dei QTL in diversi ambienti. / Agriculture is facing a decline in water availability and an increasing food demand. Novel crop strategies are needed to improve yield and resource-use efficiency in water-limited conditions. Contributing to the development of such new strategies is the main aim of the European project DROPS (DROught- tolerant yielding PlantS), in which my PhD project took place. For my study, the main plant material was a panel of 188 durum wheat cultivars. My research activity included: 1. Molecular characterization of 188 durum wheat accessions with SSR and DaRT markers; 2. Glasshouse experiments involving 100 accessions of the panel which were evaluated for Water-Use -Efficiency accordingly to an Alpha Lattice design; 3. Field trials, performed accordingly to an Alpha Lattice design, in two growing seasons: a. 2010/11; evaluation of 100 durum wheat accessions at the University experimental station in Cadriano (BO); b. 2011/12; evaluation of 188 durum wheat accessions in 3 environments, with two different water treatments. In both years, we measured plant traits related with developmental cycle, grain yield and its components, as well as a number of environmental and soil characteristics. Concerning Water-Use-Efficiency, we found highly significant differences between genotypes within the panel. In all the replicates, five accessions showed higher WUE and five lower WUE as compared to the rest of the 100 accessions under analysis. The first- and second- year field experiments evidenced highly significant differences between the lines in the panel for most of the investigated traits, and confirmed the property of the panel to flower within one week time. The second-year experiment allowed us to first investigate the genotype by environment interaction. These results will be integrated with further QTL analysis, to identify chromosomal regions involved in the genetic control of traits of interest and to verify QTL stability across environments.

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The biological complexity of NGF action is achieved by binding two distinct Neurotrophin receptors, TrkA and p75NTR. While several reports have provided lines of evidence on the interaction between TrkA and p75NTR at the plasma membrane, much fewer data are available on the consequence of such an interaction in terms of intracellular signaling. In this study, we have focused on how p75NTR may affect TrkA downstream signaling with respect to neuronal differentiation. Here, we have shown that cooperation between p75NTR and TrkA results in an increased NGF-mediated TrkA autophosphorylation, leads to a sustained activation of ERK1/2 and accelerates neurite outgrowth. Interestingly, neurite outgrowth is concomitant with a selective enhancement of the AP-1 activity and the transcriptional activation of genes such as GAP-43 and p21(CIP/WAF), known to be involved in the differentiation process. Collectively, our results unveil a functional link between the specific expression profile of neurotrophin receptors in neuronal cells and the NGF-mediated regulation of the differentiation process possibly through a persistent ERKs activation and the selective control of the AP-1 activity. In our studies we discuss the functional role of the neurotrophin receptor p75NTR and TrkA in a ligand-dependent signal transduction. It is known that p75NTR is also involved in the mediation of cell death ligand dependent. Here we show for the first time that the membrane receptor p75NTR, upon binding to b- Amyloid (Ab) peptide, is able to transduce a cytotoxic signal through a mechanism very similar to the one adopted by Tumor Necrosis Factor Receptor 1 (TNFR1), when activated by TNFa. We define that in neuroblastoma cell line Ab cytotoxicity signals through a pathway depending on p75NTR death domain (DD), mostly through some specific conserved residues. We identified that TRADD is the first interactor recruiting to the membrane and activates JNK and NF-kB transcription factors. Since Ab is defined as the most important aetiologic element associated with the Alzheimer’s Disease (AD), characterization of the mechanism involved in the mediation of the neurodegeneration can suggest also new therapeutic approaches.