Diss. (sammanfattning) Uppsala : Uppsala universitet, 2009. / Härtill 4 uppsatser.

Despite the fact that a preponderance of past studies in corporate finance mainly focus on capital structure decision of firms, the problems of “what factors determine the capital structure choice of firms and how firms adjust their capital structure dynamically” are still riddling. Hence, the aim of this study is to investigate the determinants of capital structure and capital structure adjustment dynamics of banks. To this end, the study employed a quantitative research approach. Specifically, secondary data have been collected through document review of annual reports of selected banks for longitudinal/panel research design. Besides, primary data have been collected through a self- administered questionnaire distributed to the selected Chief Financial Officers (CFOs) for the cross-sectional survey research design of the study. As the method of data analysis, the study estimates both static and dynamic panel models using fixed effect and GMM estimators respectively. Besides, in analyzing the cross-sectional survey responses, appropriate statistical techniques for order-ranked and nominal/categorical items of the responses have been employed. Specifically, in the univariate analysis of survey responses, mean scores and percentage of categorical responses have been computed for order-ranked and nominal items respectively. Moreover, to test the significance of differences of mean scores of order-ranked and percentage of responses of nominal items conditional on bank characteristics, the study employed the nonparametric Mann-Whitney test and the likelihood ratio test respectively. As the result, the tax shield from interest tax deductibility, profitability and/or size of free cash flows, growth opportunities and regulatory pressure factors are found to be significant determinants of capital structure decisions, consistently in estimations of panel models and cross-sectional survey. In iii examining the capital structure adjustment dynamics, both the regression estimation and survey results revealed the tendency of banks in Ethiopia to set target capital structure and adjust towards it at a relatively faster speed of adjustment. Besides, both regression model estimation and survey results disclose the asymmetrical target capital structure adjustment of banks. To be specific, overleveraged or undercapitalized banks adjust more quickly than underleveraged or overcapitalized banks. Further, the speed of target capital structure adjustment is found to be heterogeneous across banks that differ in their absolute deviations from target capital structure, size, regulatory pressure for capital adequacy and ownership. Hence, by empirically examining the determinants and dynamics of capital structure of banks in Ethiopia, the study contributes to the existing body of knowledge on the subject under study, and/or it fills a gap in the existing reference literature on the subject. Most importantly, the study tries to untangle the capital structure issues of banks, especially the dynamics, in the context of the least developed financial system where there are no secondary market and oligopolistic banking sector. / Graduate School of Business Leadership (SBL) / D.B.L.

Orientador: Maeli Dal Pai Silva / Tese ( doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-18T12:24:51Z (GMT). No. of bitstreams: 1 Carani_FernandaRegina_D.pdf: 24872848 bytes, checksum: e4b7c794fa866be614e932ec5a33eaf6 (MD5) Previous issue date: 2011 / Resumo: O pirarucu (Arapaima gigas) caracteriza-se como uma espécie promissora para a Aqüicultura, devido principalmente às suas características de rápido crescimento e rusticidade. Sua criação em regime intensivo tem obtido enorme sucesso, podendo alcançar até 10 quilos de peso corporal em apenas um ano de criação. O pirarucu é considerado hoje uma das mais importantes espécies de peixes da bacia Amazônica e, por esta razão, é primordial que se investigue os mecanismos celulares e moleculares que controlam o rápido crescimento muscular, contribuindo com novas estratégias de criação e com a manutenção da espécie. O crescimento do músculo estriado esquelético nos peixes pode ocorrer por dois mecanismos: hipertrofia e/ou hiperplasia das fibras, a partir de células satélites ou mioblastos. Esse processo é controlado por Fatores Reguladores Miogênicos (MRFs) e pelo fator de crescimento Miostatina. O objetivo do presente estudo foi avaliar as características morfológicas e o crescimento muscular hipertrófico e hiperplásico, bem como analisar a expressão gênica e protéica da MyoD, da Miogenina e da Miostatina na musculatura esquelética do pirarucu (A. gigas), em diferentes fases de crescimento. Os animais utilizados no presente estudo foram provenientes de duas pisciculturas: na primeira, foram obtidos os "alevinos" (pós-larvas; 48 g); na segunda, os animais em diferentes estágios de crescimento, divididos em quatro grupos de acordo com o peso corporal. Grupo A (50 gramas, n=7), grupo B (420 gramas, n=7), grupo C (5,5 quilogramas, n=7) e grupo D (9,1 quilogramas, n=7). As amostras musculares foram coletadas, congeladas e submetidas à coloração HE, para avaliação do padrão morfológico das fibras, e à reação para a enzima NADH-TR, para avaliar o metabolismo oxidativo das fibras. Para avaliar o padrão de crescimento hiperplásico e hipertrófico da musculatura branca, foi calculado o menor diâmetro de uma população de fibras por animal, e estas foram distribuídas em classes, na dependência do seu diâmetro. A análise da expressão gênica de MyoD, miogenina e miostatina foi feita por Reação em Cadeia da Polimerase após Transcrição Reversa (RTqPCR); para análise da expressão protéica, foi utilizado o Western Blot. A distribuição das fibras em classes de diâmetro exibiu o seguinte padrão: o grupo A mostrou a maior parte das fibras na classe 20, o grupo B, na classe 50, o grupo C, nas classes 50 e 80, e o grupo D, na classe 80. Isso indica uma alta taxa de hiperplasia das fibras nos grupos menores (A e B) e alta hipertrofia das fibras nos grupos maiores (C e D). Para a análise da expressão gênica de MyoD e miogenina no músculo vermelho e branco dos "alevinos", não houve diferença estatística; para a miostatina, houve expressão diferencial, com os maiores níveis encontrados no músculo branco em comparação com o músculo vermelho. Na avaliação da expressão de MyoD e miogenina, tanto a expressão gênica como a expressão protéica não mostraram diferença significativa. Por outro lado, a expressão gênica da miostatina foi menor no grupo A e maior nos demais, e a expressão da proteína miostatina foi maior no grupo A, diminuindo nos demais grupos. Estes resultados refletem as características de crescimento muscular da espécie e sugerem que a expressão dos MRFs e da miostatina são responsáveis pelo balanço entre a hiperplasia e a hipertrofia das fibras, contribuindo para o rápido crescimento da espécie e a manutenção das características do filé / Abstract: Pirarucu (Arapaima gigas) is a promising fish species for Aquaculture programs mainly by the fast growing feature and rusticity. Their rearing under intensive conditions generated much successful results, as they reach up to 10 kilograms in just one year. Considered one of the most important fish species from Amazon basin, it is of primary interest to investigate the cellular and molecular mechanisms that control the fast muscle growth in pirarucu, providing information for new rearing strategies and species conservation. In most fish, skeletal muscle growth occurs by two mechanisms: hypertrophy and hyperplasia, from satellite cells or myoblasts. These process are under control by Myogenic Regulatory Factors (MRFs) and by the growth factor Myostatin. The animals were obtained from two pisciculture, where we got the alevin pirarucu (n=7; 48 grams weight), and the specimens at different growth stages, divided into groups according body weight. Group A (50 grams, n=7), group B (420 grams, n=7), group C (5,5 kilograms, n=7) and group D (9,1 kilograms, n=7). Muscle samples were collected, frozen and stained with HE for morphological analysis, and submitted to NADH-TR enzyme reaction for oxidative methabolism analysis. To evaluate hyperplasic and hypertrophic muscle growth, it was measured the smallest diameter from a set of fibers, which were grouped into diameter classes. Gene expression analysis of MyoD, Myogenin and Myostatin were performed by Quantitative Polimerase Chain Reaction after Reverse Transcription (RT-qPCR); protein content analysis was by Western Blot technique. Muscle fibers distribution in classes showed the following pattern: group A showed most fibers in class 20, group B, in class 50, group C, in classes 50 and 80, and group D, in class 80. This is an indicative of high fiber hiperplasia rate in groups A and B, and high hypertrophy in groups C and D. There was no statistical difference in MyoD and Myogenin genes expression in red and white muscles of pirarucu; however, Myostatin expression showed high levels in white muscle compared to red muscle. Evaluating MyoD and Myogenin expression in white muscle of pirarucu at different growth stages, both gene and protein levels were similar. Myostatin gene expression was low in group A and high in the other groups; on the other hand, Myostatin protein was high in group A and low in the other groups. These results reflect the muscle growth characteristics in pirarucu and suggest that the MRFs and Myostatin expression are controlling the balance between hyperplasic and hypertrophic mechanisms, promoting the fast rate feature of pirarucu and their fillet quality / Doutorado / Biologia Celular / Doutor em Biologia Celular e Estrutural

Changes in cis- and trans-regulatory elements are among the prime sources of genetic and phenotypical variation at species level. The introduction of cis- and trans- regulatory variation has played important roles in driving diversity, phenotypical differentiation, and evolution of humans. Therefore, variation that occurs on cis- and trans- regulatory elements becomes imperative to better understanding of human genetic diversity and its evolution. In this research, around 3360 gene regulatory factors (GRF) from the human genome were catalogued. This catalog includes genes that code for proteins that perform gene regulatory activities such DNA-depending transcription, RNA polymerase II transcription cofactor and co-repressor activity, chromatin binding and remodeling, among other 218 regulatory functions. This GRF catalog allowed us to initially explore how some GRF genes have evolved in humans, archaic humans (Neandertal and Denisovan) and non-human primate species. We discussed the likely phenotypical and medical effects that evolutionary changes in GRF genes may have introduced into the human genome; for instance, traits associated to speech and language capabilities, genomic recombination hotspots, diseases, among others. By using genome-wide datasets, we additionally looked for GRFs likely to be candidates for positive selection in three human populations: Utah Residents with Northern and Western Ancestry (CEU), Han Chinese in Beijing (CHB), and Yoruba in Ibadan (YRI). As result, we produced a set of candidates that gathers genes that may have contributed in shaping the phenotypical diversity currently observed in these populations; for instance, by introducing regulatory diversity at population-specific level. We additionally identified six GRF classes enriched for genes located in regions that are likely candidates for positive selection at population specific level. We found that out of the 41 DNA-binding GRF classes classified so far, six groups exhibited enrichment for genes located on regions that may have been under positive selection: C2H2 zinc finger, KRAB-ZNF zinc finger, Homeo domain, Tryptophan cluster, Fork head/winged helix and, and High-mobility HMG domain. We additionally identified three KRAB-ZNF gene clusters, in the chromosomes one, three, and 16, for the Asian population that exhibit regions with extended haplotype homozygosity EHH (larger than 100 kb). This EHH suggests that these regions have undergone positive selection in CHB population. Finally, considering that a representative fraction of the phenotypic diversity observed between humans and its closely related species are likely explained by changes in cis-regulatory elements (CREs), we investigated putative binding sites for the transcription factor GABPa. Using ChIP-Seq data generated from a human cell line (HEK293T), 11,619 putative GABPa CREs were found, Out of which 224 are putative human-specific. To experimentally validate the transcriptional activity of these human-specific CREs, reporter gene essays and knock-down experiments were performed. Our results supported the functionality of these human-specific GABPa CREs and suggest that at least 1,215 genes are primary targets of GABPa. Finally, further analyses depict scenarios that put together transcriptional regulation by GABPa and the evolution of particular human traits; for instance, cognitive abilities, breast morphology, lipids and glucose metabolic pathways, among others.

No description available.