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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Study on Degradation mechanism of Crystallized Laterally Grown Poly-Si TFT under Electrical Stress

Chao, Tsai-Lun 10 July 2007 (has links)
In this thesis, we will investigate the degradation of the low temperature polycrystalline silicon TFTs (LTPS TFTS) under the electrical stress. The electrical stress is divided into two parts of ac stress and dc stress. We used ac stress and dc stress conditions to stress different TFTs respectively and investigate the influence of grain boundary in n-type TFT and p-type TFT by use of electrical analysis. On the other hand, degradation mechanism was confirmed by measured capacitance. In n-type TFT, the SLS poly-Si TFT which contains GB perpendicular to the channel direction owns the higher ability against dc stress and poorer ability against ac stress than the poly-Si TFT which does not contain GB. The physical mechanism for these results has been reasonably deduced by use of TFT device simulation tool (ISE_TCAD). In p-type TFT, the enhancement phenomenon is always observed after dc or ac stress. There are both existed a power-law between the variation of the drain current with stress time. The slope of power-law is related to the shortening speed of effective channel length. In either dc stress or ac stress, there are two effective factors. The one factors of them is the degradation of poly-Si film, and another one is the effective channel length shortening. In the competition of these two effective factors, the GB-TFT has more obvious enhancement than GB-TFT during dc stress. Nevertheless, during the ac stress the GB-TFT is without larger enhancement than NGB-TFT because of serious poly-Si film damage.
2

This is who I am: a phenomenological analysis of female purity pledgers' sense of identity and sexual agency

Hanna, Katrina N. January 1900 (has links)
Master of Arts / Department of Communication Studies / Soo-Hye Han / At the turn of the 21st century, an ideological movement defined by many as the modesty movement helped push sexual abstinence as a controversial yet significant public issue in the United States. Concerned with a "hyper-sexualized" culture, modesty advocates urged young women to make a pledge to remain pure until marriage. Following the the growth of the movement, feminist scholars have been critical of the movement and the potentially detrimental consequences of purity pledges on young women's identity, sexuality, and sexual agency. This study takes a step back from this critical view of purity pledges and listens to young women's lived experience of making a purity pledge and living a life of purity. Specifically, this study asks how purity pledgers understand and enact purity and how they perceive their sexuality and sexual agency. To answer these questions, qualitative interviews were conducted with nine young women who at some point in their life made a purity pledge. A thematic analysis revealed three major themes: 1) living a pure life is situated within multifaceted perspectives on purity, 2) living a life of purity consists of negotiating multiple "selves," and 3) living a life of purity grants and reinforces a sense of agency. A composite description illustrates that religious messages, parents, peers, and sex education classes continue to influence their understanding of purity and sexuality. This project concludes with a discussion of theoretical implications surrounding the idea of a "crystallized self" and practical implications of this study on an organizational, familial, and personal level.
3

Study of Thermal Properties in Zr-Al-Cu-Ni Amorphous Alloy by Adding Boron and Silicon

Hung, Tzu-Hsiang 13 July 2004 (has links)
It has been reported that the Zr-based amorphous alloys exhibit high corrosion resistance, good mechanical properties, better thermal stability and good glass-forming ability. The thermal properties of the Zr-Al-Cu-Ni amorphous alloys could be improved by adding boron and silicon that also has been reported. Therefore, the Zr-Al-Cu-Ni amorphous alloys are chosen as the base materials for investigating the effect of the thermal properties by adding boron and silicon at the same time. According to the results of the experiment, the Zr60Al7.5Cu17.5Ni10B1Si4 amorphous alloy ribbons with the highest GFA index (g value) and the value is 0.42; the maximum supercooled liquid region (DTx) is about 85 K for the Zr60Al7.5Cu17.5Ni10B1Si4 amorphous alloy ribbons. For the isothermal analysis or non-isothermal analysis, the Avrami index (n value) is not constant, and the Zr60Al7.5Cu17.5Ni10B1Si4 amorphous alloy ribbons with the largest activation energy which was more than 300 kJ/mol. When the Zr60Al7.5Cu17.5Ni10B1Si4 amorphous alloy ribbons were heated to 721 K and held for 4000 seconds, the crystallized phases were ZrO2 with orthorhombic structure and Zr2Ni with tetragonal structure. When the Zr62Al7.5Cu17.5Ni10B2Si1 amorphous alloy ribbons were heated to 724 K and held for 4000 seconds, besides the ZrO2 phase with orthorhombic structure and the Zr2Ni phase with tetragonal structure, a Zr2Ni crystallized phase with cubic structure is also included. According to the observation of the TEM image for heating Zr62Al7.5Cu17.5Ni10B2Si1 amorphous alloy ribbons to 694 K and held for 4000 seconds, there are many grains distribute in the amorphous matrix, and the grain size is about 20 ~40 nm.
4

Fluid ability, crystallized ability, and performance across multiple domains: a meta-analysis

Postlethwaite, Bennett Eugene 01 July 2011 (has links)
Cognitive ability is one of the most frequently investigated individual differences in management and psychology. Countless studies have demonstrated that tests measuring cognitive ability or intelligence predict a number of important real-world outcomes such as academic performance, vocational training performance, and job performance. Although the relationship between intelligence and real-world performance is well established, there is a lack of consensus among scholars with regard to how intelligence should be conceptualized and measured. Of the more traditional theories of intelligence, two perspectives are particularly dominant: the Cattell-Horn model of fluid and crystallized intelligence and the theory of General Cognitive Ability (GCA or g). Fluid ability (Gf) represents novel or abstract problem solving capability and is believed to have a physiological basis. In contrast, crystallized ability (Gc) is associated with learned or acculturated knowledge. Drawing on recent research in neuroscience, as well as research on past performance, the nature of work, and expert performance, I argue that compared to measures of fluid ability, crystallized ability measures should more strongly predict real-world criteria in the classroom as well as the workplace. This idea was meta-analytically examined using a large, diverse set of over 400 primary studies spanning the past 100 years. With regard to academic performance, measures of fluid ability were found to positively predict learning (as measured by grades). However, as hypothesized, crystallized ability measures were found to be superior predictors of academic performance compared to their fluid ability counterparts. This finding was true for both high school and college students. Likewise, similar patterns of results were observed with regard to both training performance and job performance. Again, crystallized ability measures were found to be better predictors of performance than fluid measures. This finding was consistent at the overall level of analysis as well as for medium complexity jobs. These findings have important implications for both intelligence theory and selection practice. Contemporary intelligence theory has placed great emphasis on the role of fluid ability, and some researchers have argued that Gf and g are essentially the same construct. However, the results of this study, which are based on criterion-related validities rather than factor-analytic evidence, demonstrate that Gc measures are superior predictors in comparison to Gf measures. This is contrary to what one would expect if Gf and g were indeed the same construct. Rather, the findings of this study are more consistent with General Cognitive Ability theory, which predicts that Gc indicators will be the best predictors of future learning and performance. Given that Gc measures demonstrate higher criterion-related validities than Gf measures, Gc measures are likely to be preferred for selection purposes. Further, Gf scores are known to decline with age while Gc scores remain relatively stable over the lifespan. Thus, when used for selection purposes, Gf tests may underpredict the performance of older workers. In contrast, research has shown that Gc measures are predictively unbiased. Additional implications for theory and practice are discussed, along with study limitations and opportunities for future research.
5

Sleep, Depressive Symptoms and Cognition in Older Adults and Caregivers of Persons with Dementia

Brewster, Glenna Shemida 01 January 2015 (has links)
Caregivers of persons with dementia, who are often older adults, report sleep disturbance, high rates of depressive symptoms and may be at risk for impaired cognition. This dissertation examined sleep, depressive symptoms, and cognition in older adults and caregivers of persons with dementia. The aims of the review of literature were to understand, in community dwelling adults 60 years and older, the relationships among sleep parameters (sleep onset latency, wake after sleep onset, sleep efficiency, total sleep time, and general sleep complaints), and the domains of cognition (Executive Function, Attention, Episodic Memory, Working Memory, Processing Speed), and global cognition. Based on the findings, the research on the association of subjective sleep parameters and cognition is inconclusive and there is insufficient evidence to confirm or deny the existence of a relationship between objective sleep parameters and cognition. The methods section examined whether in adults 60 years and older, Radloff’s postulated 4-factor structure replicates across Afro-Caribbean Americans, African-Americans, Hispanic-Americans, and European-Americans and determine whether there is evidence for measurement invariance across the four ethnic groups in their responses to the Center for Epidemiological Depression Scale (CES-D) statements. Radloff’s postulated 4-factor model fit the data adequately and the results suggest that there is evidence for configural and partial metric invariance. The final section examined the relationships among subjective sleep parameters (Sleep Onset Latency, Wake After Sleep Onset, Total Sleep Time, Time in Bed, Sleep Efficiency, Sleep Quality), depressive symptoms, and, crystallized, fluid and total cognition in caregivers of persons with dementia with poor sleep. Based on the findings, depressive symptoms also did not mediate the ability of the sleep parameters to predict cognitive performance. With the knowledge that there are potential associations among sleep parameters, depressive symptoms and cognition in caregivers, healthcare providers should collect baseline assessments on sleep, depressive symptoms and cognition from caregivers and monitor them on an ongoing basis to identify changes and intervene in a timely manner. More research studies incorporating measures to capture sleep variability and similar cognitive measures, are needed to clarify the relationships both in older adults and caregivers of persons with dementia.
6

The Shifting Role of Fluid Reasoning in Reading

Droder, Sarah January 2021 (has links)
No description available.
7

Training and Practice Effects on Performance Attributions Among Non-Depressed and Depressed Older Persons

Segal, Carolyn 12 1900 (has links)
Previous research examining the impact of training and practice effects on modifying performance of fluid intelligence tasks (Gf) and crystallized intelligence tasks (Gc) were extended to include self-rated performance attributions among non-depressed and depressed older persons. The following general questions were addressed. How does level of depression affect performance on Gf and Gc measures and performance attributions? How does level of depression and degree of benefit from either training or practice relate to changes in attributional styles? The framework used for predicting shifts in attributional styles was the reformulated learned helplessness model. Three hundred twenty-five community-dwelling older persons completed the Gf/Gc Sampler, Beck Depression Inventory, and Attributions for Success/Failure Questionnaire at pretest, posttest (one week), and follow-up (one month). Between the pretest and posttest sessions, subjects participated in one of three experimental conditions; (a) cognitive (induction) training, (b) stress inoculation training, and (c) no-contact control groups. The results from univariate and multivariate analysis of covariance procedures provided partial support for the hypotheses. At pretest, both non-depressed and depressed older persons had internal attributional styles, although based on differential performance outcomes. The depressed persons were found to have more failure experiences as a result of their significantly poorer performance on Gf tasks, versus the non-depressed. Specific Gf training effects were documented regarding attributional shifts for the non-depressed, while there were no changes on their attributional style due to practice on either Gf or Gc tasks. In contrast, only differential practice effects were documented for depressed subjects across Gf and Gc tasks. The importance of assessing personality dimensions in older persons and their xelationship to training and practice effects were discussed, in addition to limitations of the study and suggestions for future research.
8

Verbo-suporte e expressões cristalizadas: um enfoque sintático-semântico-discursivo / Support-verb and usual cristallized expressions: analysis proposal of discursive and semantic values

Hilda Monetto Flores da Silva 31 July 2006 (has links)
Esta dissertação apresenta uma proposta de análise dos valores semânticos e discursivos de construções com verbo-suporte e de expressões cristalizadas correntes na língua portuguesa do Brasil. O corpus analisado é constituído de textos de gêneros variados colhidos em jornais e revistas publicados desde 2003, nos quais se evidencia o aparecimento cada vez mais freqüente dos usos verbais em foco. Parte-se do pressuposto teórico de que o verbo é o nó a ser desatado, pois, ao contrário, do que muitos autores vêm relatando em relação ao verbo-suporte, não há um completo esvaziamento semântico, mas uma nova forma de dizer em que se privilegia o uso conotativo do verbo que passa de pleno a leve, segundo a nomenclatura de vários estudiosos, que lhe atribuem valor de auxiliaridade. Enquanto o uso dos verbos-suporte no Brasil vem-se fixando no léxico, outras formas cristalizam-se, enriquecendo o vocabulário, inovando falares, o que aproxima estas expressões de uma classe aberta. O verbo somado a alguns nomes ou participando de expressões, longe de se esvaziar, estendem ou modificam a significação no processo discursivo. / This dissertation presents an analysis proposal of discursive and semantic values of wordings using a support-verb and of usual crystallized expressions in the Portuguese language in Brazil. The corpus analyzed is composed by texts of different classes, collected from newspapers and magazines published since 2003, which evidence the increasing appearance of the verbal uses focused. This work starts from the theoretical presupposition that the verb is a knot to be undone; differently from what many authors have been reporting relatively to the support-verb, there is not a complete semantic emptying, what exists is a new way of speaking, in which is privileged the connotative use of the verb, which changes from heavy to slight, according to the nomenclature used by many scholars, who attribute it a value of assistance. While the use of support-verbs in Brazil has been focusing lexical aspects, other different ways have appeared, enriching the vocabulary and reforming ways of speaking. This brings these expressions closer to an open class. The verb added to some nouns or taking part in expressions, far from emptying itself, enlarges or modifies its meaning in the discursive process.
9

Verbo-suporte e expressões cristalizadas: um enfoque sintático-semântico-discursivo / Support-verb and usual cristallized expressions: analysis proposal of discursive and semantic values

Hilda Monetto Flores da Silva 31 July 2006 (has links)
Esta dissertação apresenta uma proposta de análise dos valores semânticos e discursivos de construções com verbo-suporte e de expressões cristalizadas correntes na língua portuguesa do Brasil. O corpus analisado é constituído de textos de gêneros variados colhidos em jornais e revistas publicados desde 2003, nos quais se evidencia o aparecimento cada vez mais freqüente dos usos verbais em foco. Parte-se do pressuposto teórico de que o verbo é o nó a ser desatado, pois, ao contrário, do que muitos autores vêm relatando em relação ao verbo-suporte, não há um completo esvaziamento semântico, mas uma nova forma de dizer em que se privilegia o uso conotativo do verbo que passa de pleno a leve, segundo a nomenclatura de vários estudiosos, que lhe atribuem valor de auxiliaridade. Enquanto o uso dos verbos-suporte no Brasil vem-se fixando no léxico, outras formas cristalizam-se, enriquecendo o vocabulário, inovando falares, o que aproxima estas expressões de uma classe aberta. O verbo somado a alguns nomes ou participando de expressões, longe de se esvaziar, estendem ou modificam a significação no processo discursivo. / This dissertation presents an analysis proposal of discursive and semantic values of wordings using a support-verb and of usual crystallized expressions in the Portuguese language in Brazil. The corpus analyzed is composed by texts of different classes, collected from newspapers and magazines published since 2003, which evidence the increasing appearance of the verbal uses focused. This work starts from the theoretical presupposition that the verb is a knot to be undone; differently from what many authors have been reporting relatively to the support-verb, there is not a complete semantic emptying, what exists is a new way of speaking, in which is privileged the connotative use of the verb, which changes from heavy to slight, according to the nomenclature used by many scholars, who attribute it a value of assistance. While the use of support-verbs in Brazil has been focusing lexical aspects, other different ways have appeared, enriching the vocabulary and reforming ways of speaking. This brings these expressions closer to an open class. The verb added to some nouns or taking part in expressions, far from emptying itself, enlarges or modifies its meaning in the discursive process.
10

Associação entre volume cerebral e medidas de inteligência em adultos saudáveis: um estudo por ressonância magnética estrutural e volumetria baseada em voxel / Association between brain volume and intelligence measures in healthy adults: a structural magnetic resonance study and voxel-based volumetry

Duarte, Everton 26 September 2011 (has links)
Introdução: As funções cognitivas sofrem influência da idade, tanto no seu desenvolvimento como no seu declínio. De forma geral, as medidas de inteligência se relacionam com o volume de substância cinzenta (SC) em áreas cerebrais específicas e sofrem influência com o processo de envelhecimento. Em crianças e adolescentes as áreas envolvidas são o córtex pré-frontal, enquanto nos idosos e adultos jovens os córtices frontais e temporais desempenham um papel importante. Objetivo: Identificar quais áreas cerebrais estão implicadas nas variações das medidas de inteligência em uma amostra representativa de adultos jovens e idosos saudáveis. As hipóteses principais são: 1) haverá uma associação indireta entre distribuição de SC e idade envolvendo áreas de córtex frontal e temporal; 2) em adultos, as medidas de QI estimado irão se mostrar estáveis em decorrência da estabilidade entre as funções de inteligência fluida e cristalizada; 3) em idosos, as medidas de QI estimado apresentarão correlação direta com a distribuição de SC envolvendo o córtex temporal e límbico; 4) em idosos, as medidas de inteligência fluida apresentarão correlação direta com a distribuição de SC em córtices frontal e pré-frontal; 5) em idosos, as medidas de inteligência cristalizada não apresentarão correlações significativas com a distribuição de SC. Metodologia: Os exames de imagens cerebrais foram obtidos a partir de uma amostra representativa com ampla faixa etária. Foi investigada uma amostra de 258 sujeitos entre 18 e 75 anos que preencheram os critérios de inclusão/exclusão, e para os quais é possível estimar o QI através de subtestes do WASI. Os resultados estatísticos de cada análise foram realizados utilizando a volumetria baseada em voxel sob a forma de mapas paramétricos estatísticos e a relação dos resultados foram somente os que sobreviveram a correção para comparações múltiplas. Todos os resultados foram corrigidos através das variáveis de confusão (protocolo,aparelho de ressonância magnética e volume cerebral). Resultados: Identificamos correlações entre QI estimado e de inteligência fluida em regiões temporais mediais e límbicas bilaterais, na população idosa. Na população adulta também identificamos correlações entre inteligência cristalizada envolvendo regiões frontais e pré-frontais direita. Observamos também que houve perda de SC na população adulta envolvendo as regiões pré-frontais e frontais à esquerda. Conclusão: As medidas de inteligência cristalizada e fluida apresentaram correlação direta com o volume cerebral total, e especificamente em córtices frontais, pré-frontais bilaterais, e em regiões temporais e límbicas / Introduction: The cognitive functions could be influenced by age, both during the development as well as during the decline. Measures of intelligence in general are related to the volume of gray matter (GM) in specific brain areas, and also are under influence of aging process. In children and adolescents the brain areas involved is mainly the prefrontal cortex, while in the elderly other areas, such as the frontal and temporal cortices play an important role. Objective: To identify which brain areas are involved in variations in intelligence measures in a representative sample of large age span, from young adults to healthy elderly. The main hypotheses are: 1) there would be an indirect association between age distribution of GM and surrounding areas of the frontal and temporal cortex, 2) in adults, estimated IQ measures would prove to be stable secondarily to adaptation between fluid intelligence and crystallized functions, 3) in the elderly, measures of IQ estimated would present direct correlation with the distribution of GM involving the temporal cortex and limbic, 4) in the elderly, measures of fluid intelligence would show a direct correlation with the distribution of GM and pre frontal cortices, 5) in the elderly, measures of crystallized intelligence would not present significant correlations with the distribution of GM. Methods: Brain images scans were obtained from a representative sample with large age span. We investigated a sample of 258 subjects between 18 and 75 who met the criteria for inclusion / exclusion, and for which it is possible to estimate the IQ subtests by the WASI. Correlation statistical analyses were performed using voxel-based methodology with Statistical Parametric Map Software, and reported only if survived multiple comparison correction. All results were corrected for confounding variables (protocol, MRI scan and total brain volume). Results: We identified correlations between IQ and estimated fluid intelligence in medial temporal and limbic regions bilateral in the elderly. In the adult population we also identified correlations between crystallized intelligence involving the frontal and prefrontal right. We also observed that there was loss of GM in adults involving the left prefrontal regions and frontal. Conclusion: Measures of fluid and crystallized intelligence showed direct correlation with the total brain volume, and specifically in the frontal cortex, bilateral prefrontal, and temporal and limbic regions

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