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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.
501

O efeito da implementação de um site sobre os preços das ações das empresas brasileiras negociadas na BOVESPA

Baptista, Evelyn Maria Boia January 2001 (has links)
Os avanços nas Tecnologias de Informação, em especial a Internet, e a sua aplicação para fins comerciais, trouxe transformações para as empresas, no que se refere ao relacionamento com clientes, fornecedores e parceiros, e ao seu ambiente interno. A forma mais elementar que evidencia a conexão das empresas com essa tecnologia é a presença na rede, através de um site1. Este trabalho explora o papel da implementação de um site de uma S.A. na explicação da variação dos preços das suas ações no mercado de capitais brasileiro. O presente estudo tem por objetivo investigar se o mercado precifica a iniciativa das empresas em ingressarem no mundo virtual através da criação de um site próprio. Para uma amostra de 36 empresas brasileiras de capital aberto com ações negociadas em bolsa de valores, verificou-se, através de um estudo de evento, que a implementação do site de uma S.A. não afetou o preço de suas ações na data do evento e ao redor desta, para um período de doze meses, o que implica a aceitação da hipótese nula. Entretanto, quando realizada a segmentação da amostra por ano de lançamento do site2 e por versão do lançamento3, os resultados diferenciam-se daqueles da análise da amostra completa. Com relação aos resultados provenientes da segmentação por ano de lançamento, foram encontrados retornos anormais negativos significativos ao nível de 10% para o ano de 1995, retornos positivos significativos ao nível de 5% para o ano de 1997 e retornos positivos significativos ao nível de 10% para o ano de 2000. Para os demais anos, não foram encontrados retornos anormais significativos. Quanto aos resultados da segmentação por versão implementada, a primeira versão do site para estas empresas não resultou na existência de retornos anormais significativos, o que implica a aceitação da hipótese nula. Para as empresas cuja implementação da 2° versão foi analisada, observou-se a existência de retornos anormais negativos ao nível de significância de 10% na data +1, correspondente mês um da janela do evento.
502

Sítios históricos brasileiros: monumento, documento, empreendimento e instrumento - o caso de Sobral - CE / Brazilian historic sites: monument, document, enterprise and instrument - the case of Sobral/CE

Romeu Duarte Junior 02 July 2012 (has links)
O presente trabalho trata das relações estabelecidas entre a preservação do patrimônio edificado e o planejamento e a gestão urbana do sítio histórico da Cidade de Sobral, tombado pelo Instituto do Patrimônio Histórico e Artístico Nacional - IPHAN em 1999. Com ênfase para as novas abordagens do tombamento federal de áreas urbanas no Brasil e em outros países, em seus aspectos políticos, gerenciais e transformadores, a experiência de preservação urbana em Sobral é analisada sob a ótica dos conceitos de cidade-monumento, cidade-documento, cidade-empreendimento e cidade-instrumento, esta a hipótese principal da tese. / This work deals with relations established between the preservation of the built cultural heritage and urban planning and management of the historic site of Sobral, protected as nacional monument by Instituto do Patrimônio Histórico e Artístico Nacional - IPHAN since 1999. Emphasizing new approaches of the federal listing of urban areas in Brazil and other coutries, in its political, administrative and changing aspects, Sobral urban preservation experience is analyzed trough the concepts of cidade-monumento, cidade-documento, cidade-empreendimento e cidade-instrumento, this the main hipothesis of the work.
503

Site-Directed Mutagenesis in Citrus paradisi Flavonol-Specific 3-O-Glucosyltransferase

Khaja, Sara 01 December 2014 (has links)
Flavonoids are plant secondary metabolites that have significant biochemical and physiological roles. Biosynthesis of these compounds involves several modifications, most predominantly glucosylation, which is catalyzed by glucosyltransferases (GTs). A signature amino acid sequence, the PSPG box, is used to identify putative clones and has been shown to be involved in UDP-glucose binding. Site-directed mutagenesis is used to answer questions regarding the structure and function of this family of enzymes, particularly what allows some GTs to be more selective towards some substrates than others. The grapefruit (Citrus paradisi) flavonol-3-O-glucosyltransferase (CpF3GT) is specific for flavonol substrates and will not glucosylate anthocyanidins. Comparison of the CpF3GT sequence with that of Vitis vinifera GT, which glucosylates both flavonols and anthocyanidins, provided the basis for the amino acid substitution of proline 145, alanine 374, and alanine 375 in CpF3GT to threonine, aspartate, and glycine, respectively, to test the affect on GT’s affinity for flavonoid substrates.
504

Additional Research and Taxonomic Resolution of Salamanders (Amphibia: Caudata) from the Mio-Pliocene Gray Fossil Site, TN

Darcy, Hannah E 01 May 2015 (has links)
The Gray Fossil Site (GFS), a Mio-Pliocene (4.5–7 Ma) locality in the southern Appalachians, boasts the most diverse pre-Pleistocene salamander fauna in North America: Desmognathus sp., Plethodon sp., Notophthalmus sp., a Spelerpinae-type plethodontid, and Ambystoma sp. Because greater taxonomic resolution can result in more precise paleobiological interpretations, additional specimens were studied here. ETMNH 8045, a nearly complete articulated ambystomatid, appears most like Ambystoma maculatum in dentition and vertebral proportions. ETMNH 18219, an isolated vomer, is consistent with modern Pseudotriton and Gyrinophilus in possessing a postdentigerous process and a similar dentigerous row morphology. If these taxa, or species of similar ecological preferences, occurred around the GFS, it seems unlikely they co-inhabited the sinkhole lake. Aquatic stages of Pseudotriton and terrestrial Gyrinophilus last multiple years; their presence could further support a perennial lake interpretation. Modern A. maculatum preferentially breed in vernal pools; confirmed identification could suggest local seasonal wetlands.
505

Sciurids (Rodentia: Sciuridae) of the Late Mio-Pliocene Gray Fossil Site and the Late Miocene Tyner Farm: Implications on Ecology and Expansion of the Sciurid Record

Crowe, Cheyenne J 01 May 2017 (has links)
Sciurids are one of the most diverse mammalian groups today, but the fossil record does not reflect that diversity. The purpose of this project was to identify sciurids from two late Miocene sites—the Gray Fossil Site (GFS) of Tennessee, and Tyner Farm of Florida—and use those identifications to infer the ecology of the two. From the GFS four sciurids were identified: Eutamias or Neotamias, Glaucomys, and two tree squirrels (Sciurini). Two sciurids were identified from Tyner Farm: a chipmunk attributed to Tamiina, and a ground squirrel attributed to Marmotina. Paleoenvironmental inferences based on the sciurids present at both sites are consistent with previous work. The GFS Eutamias or Neotamias is the first record of a western chipmunk population in eastern North America; the GFS tree squirrels are the earliest record of a tree squirrel in eastern North America. The GFS Glaucomys is the earliest record of the genus.
506

New Records of Colubrids from the late Hemphillian Gray Fossil Site of Northeastern Tennessee

Jurestovsky, Derek J 01 May 2016 (has links)
The Gray Fossil Site is a rich Hemphillian (North American Land Mammal Age) locality located in northeastern Tennessee which has produced tens-of-thousands of fossils of multiple taxa including hundreds of individual snake skeletal remains. Analyzed here are cranial and vertebral fossils identified as belonging to various colubrid taxa including Carphophis sp., Gyalopion sp., Heterodon sp., Natricinae indeterminate, Thamnophis sp., and a new, undescribed genus and species. In addition, multiple new features of snake vertebrae are described, some of which question the validity of the genus Neonatrix. Finally, the distribution and paleoecology of the listed genera allows an interpretation of how snake biogeography have transformed in the southern Appalachians since the Hemphillian.
507

Peccaries (Artiodactyla: Tayassuidae) from the Late Miocene to Early Pliocene Gray Fossil Site: Regional Implications with a Review of Tayassuinae

Doughty, Evan M 01 May 2016 (has links)
Analysis of the Gray Fossil Site peccary material indicates the presence of up to three species. Comparisons with the tayassuid material known from the Tyner Farm and Bone Valley Formation of Florida allows the identification of Mylohyus elmorei and at the GFS. Within the GFS material, Prosthennops cf. P. serus and cf. Catagonus sp. are also tentatively recognized but further verification is required. The known range for Prosthennops is expanded into the Appalachian region. Presence of M. elmorei at the Gray Fossil Site provides the first known occurrence of this species outside of the Palmetto fauna of Florida, indicating that the species once exhibited a larger range within the southeastern United States than previously known. Overall, the presence of M. elmorei.indicates another parallel to the Palmetto Fauna of the Bone Valley Formation whereas Prosthennops cf. P. serus may indicate a connection to the Hemphillian of the western United States.
508

SIRA : sistema de relacionamento associativo

Lírio, Alberto Manuel Martins Conceição January 2007 (has links)
Tese de mestrado. Tecnologia Multimédia. Faculdade de Engenharia. Universidade do Porto, Faculdade de Belas Artes. Universidade do Porto. 2007
509

The heart of the park

Crum, Susanna Garts 01 May 2012 (has links)
The Heart of the Park works to expose, preserve, and interpret the many layers of social history, fact, and fiction within Iowa City's City Park. This exhibition is a result of archival research, interviews, and on-site investigation. As a guide, I followed the path of Enoch Emery, a park-haunting voyeur featured in Flannery O'Connor's first novel, Wise Blood, which she wrote after graduating from the Iowa Writers' Workshop. Details of O'Connor's fictional version of City Park, in Chapter 5 of Wise Blood, as well as Enoch's relationship with the park, led to further discoveries regarding the park's history, and ultimately, a reinterpretation of these seemingly disparate layers of fact and fiction. While the contemporary archive claims depoliticized and anonymous reasons and methods for preservation, my hybrid practice creates a role for the subjective, idiosyncratic archivist, who suffuses factual research with myth-making. The Heart of the Park is one glimpse into an ongoing collection of interpreted sites, in which I attempt to prevent the loss of local histories, and enact the inevitable chain of reinterpretations of site.
510

The A-Site In The Pkg Iα Regulatory Domain Controls Both Cgmp- And Oxidative-Dependent Activation

Sheehe, Jessica Lynne 01 January 2018 (has links)
The type Iα cGMP-dependent protein kinase (PKG Iα) is an essential regulator of vascular tone and systemic blood pressure. Located in the smooth muscle of resistance vessels, PKG Iα stimulates vasodilation through the phosphorylation of multiple intracellular substrates. Its primary regulator is the small molecule, 3',5'-cyclic guanosine monophosphate (cGMP); however, the Iα isoform can also be activated by oxidation. Despite the established physiological importance of PKG Iα, the structural underpinnings of these two activation mechanisms are largely unknown. The work presented in this dissertation demonstrates the importance of the cGMP-binding domain A (CBD-A) in regulating both of these mechanisms of PKG Iα activation. Using a monomeric, N-terminally truncated form of PKG Iα (Δ53), Chapter 2 investigates the mechanism of inhibition through the autoinhibitory domain and the influence of dimerization on cooperative cGMP-dependent activation and cyclic nucleotide selectivity. We observed that autoinhibition occurs in cis, whereas cooperativity requires interprotomer contacts facilitated by the N-terminal dimerization domain. Furthermore, the loss of selectivity for cGMP over cAMP of this construct suggests the dimerization domain plays a critical role in preventing cross-reactivity with cAMP-dependent signaling. These observations culminate into an overarching model wherein binding of cGMP to CBD-A is necessary and sufficient for activation and cooperativity is driven by the dimerization domain. Chapter 3 investigates the cysteine residues that mediate oxidation-dependent activation of PKG Iα. Using PKG Iα constructs with point mutations at specific cysteine residues, it was found that oxidation-dependent activation is driven by C117 in CBD-A. Furthermore, the interprotomer disulfide bond that forms in the dimerization domain at C42 does not contribute to this mechanism. Finally, we propose a model wherein the disulfide bond that forms between C117 and the adjacent cysteine at position 195 acts as a protective mechanism to prevent activation and higher oxidation states form contacts with nearby residues in the linker region of PKG Iα to disrupt binding of the adjacent autoinhibitory domain to the catalytic domain. Finally, Chapter 4 provides a discussion of the results presented herein in context with previous studies and suggests future directions for the PKG field.

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