Thesis (Ph.D.)--York University, 2004. Graduate Programme in Sociology. / Typescript. Includes bibliographical references (leaves 248-258). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ99200

Thesis (Ph. D.)--University of Texas at Austin, 2006. / Vita. Includes bibliographical references.

This study examined a measure of children's memory for information from a story about a hypothetical mother and child, the Story Task, as a potential tool to delineate subtypes of aggressive children based on the pattern of information processing revealed through their Story Task performance. The Story Task scores of 263 second and third grade aggressive children were subjected to a cluster analytic procedure. Although four apparently distinct subgroups emerged from the cluster analysis (negative recall, low recall, defensive processing, and positive projection), validation analyses of these clusters against external variables failed to reveal significant group differences. Potential exaplanations for the failure to find meaningful subgroups of aggressive children and general limitations of the study are discussed.

The cyclic instability in shape memory characteristics of NiTi-based shape memory alloys (SMAs), such as transformation temperatures, transformation and irrecoverable strains and transformation hysteresis upon thermal and mechanical cycling limits their applications requiring high number of cycles. The main reasons for these instabilities are lattice incompatibility between transforming phases and relatively low lattice resistance against dislocation motion. The objective of this study is to increase the slip resistance and thus, to minimize the plastic accommodation upon phase transformation in NiTi and TiNiPd SMAs. The effects of grain refinement down to submicron to nanorange through Equal Channel Angular Extrusion (ECAE) on the cyclic stability were investigated as potential remedies. The influence of ECAE parameters, such as processing temperature and strain path on the microstructural refinement was explored as well as the corresponding evolution in the stress differential between the yield strength of martensite and the critical stress to induce martensite and SMA characteristics of Ni49.7Ti50.3, Ti50Ni30Pd20, and Ti50.3Ni33.7Pd16 SMAs. Severe plastic deformation via ECAE at temperatures from 300°C up to 450°C refined the grains from 50μm down to a range between 0.03μm and 0.3μm in Ni49.7Ti50.3 and 0.5μm and 1μm in TiNiPd alloys. Regardless of the material, the lower the ECAE temperature and the higher the ECAE strain path, the better the cyclic stability. ECAE led to an increase in the stress differential between the yield strength of martensite and critical stress to induce martensite due to observed microstructural refinement and this increase is responsible for the improvement in the cyclic stability of the aforementioned SMA characteristics in all investigated materials. Addition of Pd to the NiTi alloy reduced the thermal hysteresis from 36°C down to 11°C, and enhanced the cyclic stability of the SMA characteristics. In additions to positive influence of ECAE on cyclic stability, it also led to an increase in the fracture stress levels of the TiNiPd alloys due to the fragmentation or dissolution of the precipitates responsible for the premature failures. ECAE caused a slight reduction in the work output; however it was possible to obtain large stable work outputs under higher stress levels than unprocessed materials.

Ce travail s'intéresse à l'effet de la catégorisation raciale et de genre dans la mémoire des visages. Les études effectuées montrent que la première induit une polarisation de la seconde. Ainsi, des visages catégorisés dans une catégorie particulière sont rappelés comme plus typiques de leur catégorie et moins typiques de catégories alternatives. Cet effet est observé à la fois dans le cas de visages fortement ambigus catégorisés sur base du contexte et dans le cas de visages modérément ambigus catégorisés sur base de leurs traits. Les implications pratiques et théoriques de ces résultats sont discutées.

Denne avhandlingen studerer hvordan gruppevare, nærmere bestemt Corporate Memories(CM), kan brukes til å støtte informasjons- og kunnskapsdeling i en systemutviklingsorganisasjon. Studiet tar utgangspunkt i Borghoff&amp;Pareschi’s(1998) syn på Corporate Memory som en infrastruktur for kunnskapsforvaltning i organisasjoner. CM består av fire komponenter som alle må støttes av ulike typer teknologi. Sentralt her står CSCW/gruppevare, informasjons og kunnskapsrepositorier, ontologier og bruk av metadata. Relevante sider av disse forskningsområdene er presentert i studiet. Et informasjons- og kunnskapsrom er et spesialtilpasset perspektiv inn i organisasjonens Corporate Memory for en avgrenset del av organisasjonen. I dette studiet er det tatt utgangspunkt i systemutvikling, men prinsippene vil være de samme også for andre typer virksomhet. Ved hjelp av infrastrukturen, CM, får organisasjonens medarbeidere tilgang til <b>informasjon, kunnskap og tjenester</b> som er tilpasset behovene i de arbeidsprosessene de utfører. Studiet presenterer et sett med krav til innhold, struktur og tjenester som må finnes i organisasjonens Corporate Memory. Hvis disse er oppfylt, vil det også være mulig å etablere de nødvendige Informasjons- og kunnskapsrommene i organisasjonen. Informasjons og kunnskapsrommet skal aktivt bidra til at systemutviklerne gjenbruker relevant informasjon, kunnskap og erfaringer. Dette gjelder den eksplisitte informasjonen og kunnskapen som er lagret i repositorier og det gjelder den tause kunnskapen som kun er lagret i hodene på organisasjonens medarbeidere. Avhandlingen konkluderer med at det viktigste bidraget for informasjons- og kunnskapsforvaltning i en organisasjon, er at det utvikles konseptuelle modeller for de ulike domenene i organisasjonen. Ved hjelp av metadata som avledes fra de konseptuelle modellene, kan organisasjonens informasjons- og kunnskapsressurser modelleres slik at de tilpasses virksomheten og de konkrete mål og problemstillinger som finnes her. I tillegg kan den konseptuelle modellen brukes som et redskap for bevisstgjøring, kommunikasjon, refleksjon og læring rundt arbeidsprosessene i organisasjonen. På grunnlag av intervjuer og diskusjoner med to store prosjekter i den sentrale systemutviklingsenheten i Statoil, blir det utarbeidet en ontologi for utvalgte deler av systemutviklingprosessene i Statoil. Ontologien og metadatasettet som avledes av ontologien, kan benyttes som et rammeverk for beskrivelse og forvaltning av informasjons- og kunnskapsressurer i store systemutviklingsprosjekter. Rammeverket består av flere subsett med metadata. Et av disse subsettene er obligatorisk for alle informasjonsobjekter i systemutvikling. De andre subsettene er tilpasset spesielle typer informasjon eller støtte til spesielle problemstillinger.

The conventional floating gate NVSM will suffer some limitations for continued scaling of the device structure. The floating gate is a continuous semiconductor thin film which charges are stored in and able to move around. With the scaling of tunneling oxide, the thickness is decreased gradually. Once the tunneling oxide has been created a leaky path, all the stored charges in the FG will be lost after numerous counts of write/erase operation. When the tunnel oxide is thinner, the phenomenon happens more easily but the speed of write/erase operation is quicker. Therefore, there is a tradeoff between speed and reliability.Therefore, two approaches, the silicon-oxide-nitride-oxide-silicon (SONOS) and the nanocrystal nonvolatile memory devices, have been investigated to overcome the limit of the conventional floating gate NVSM. In this thesis, the nonvolatile nanocrystal memory structures were proposed for electrical analysis and physical mechanism studied. We proposed two nanocrystal memory, silicon nanocrystal memory and nickel-silicide nanocrystal memory. The silicon nanocrystal memories have standard sample and nitridation sample. The interface between the nitride and Si-dots can offer extra trap cites for electrons storage. And the nickel-silicide dots memory has standard sample and high-k sample. The HfO2 layer for control oxide can increase the electric field of the tunnel oxide to get better programming efficiency.

Flash memory is one sort of non-volatile memory, focus on the dates holding and capacity. Conventional non-volatile memory applies poly-crystalline for floating gate material, because the poly-crystalline (like poly-silicon) itself is the semiconductor material, will cause leakage problem, recently, Oxide-nitride-oxide multi-layer structure is under development for the place of conventional floating gate. Because it is the insulator material, can suppress leakage current, and it contains a deeper trapping energy level, and has a partial trapped carriers phenomenon to give a multi-bits memory solution. My effort is to propose a pair of ONO three layers stack, which is located close to the beneath of D/S region and a column like. Such structure can overcome miniaturization limitation of channel length, and a somewhat depth oxide can promise good isolation and separation between the trapping layer and other area, and a reliable distance of the two trapped unit can prevent interference issue. My proposal can suppose a higher devices density and a feasible and flexible solution to develop memory devices, a cost down to be more competitive, certainly bring much favor for the future improvement.

In this thesis we consider estimation of the tail index for heavy tailed stochastic volatility models with long memory. We prove a central limit theorem for a Hill estimator. In particular, it is shown that neither the rate of convergence nor the asymptotic variance is affected by long memory. The theoretical findings are verified by simulation studies.

Fine motor skills are learned through repetitive practice and once learned, last for a long time. Skilled reaching is linked to structural and functional changes in multiple brain regions including, in particular, the primary motor cortex. Previous studies demonstrated that fine motor skill learning is associated with cortical synaptogenesis and motor map reorganization. At present, studies have implicated an indispensable role of epigenetic alterations in both hippocampal- and striatal-dependent memory formations, while examinations into the epigenetic changes in the primary motor cortex are lacking. The current study was aimed to identify epigenetic changes in motor cortex as a result of extensive motor skill learning using the single pellet skilled reaching task. Male Wistar rats were trained in the single pellet skilled reaching task (n = 6) for 10 consecutive days or were, under similar conditions, given access to pellets that did not require skilled reaches (n = 6). Skilled motor trained rats exhibited a rapid increase in successful reaches during the first four days of motor training before reaching a plateau, indicative of the acquisition and consolidation of the learned task, respectively. Expression profiles of chromatin modifying enzymes were screened using epigenetic-targeted PCR arrays. Results suggest that gene expression levels of multiple chromatin regulatory enzymes were down-regulated in the motor cortex of trained animals compared to controls following 10 days of motor training in the skilled reaching task. Among the chromatin modifying enzymes, the transcription level of Smyd1 (SET and MYND domain containing 1; NM_001106595) was lower (-2.17 fold-change) in motor cortex after 10 days of training compared to controls. Our results point to an epigenetic regulation of chromatin modification markers in the primary motor cortex that possibly underlie the mechanisms of synaptic plasticity, synaptogenesis and the formation of procedural memory.