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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

Prevalência de parasitas intestinais e caracterização genotípica de Giardia duodenalis em creche do município de Pratânia, estado de São Paulo

David, Érica Boarato [UNESP] 24 February 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:24:15Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-24Bitstream added on 2014-06-13T19:30:55Z : No. of bitstreams: 1 david_eb_me_botfm.pdf: 680578 bytes, checksum: 9ccd08f14d2896ddd592fa21e3bcaaba (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / O presente estudo foi realizado para investigar a prevalência de enteroparasitas em crianças e funcionários da creche do município de Pratânia, Estado de São Paulo, e caracterizar geneticamente os isolados de Giardia duodenalis obtidos dos indivíduos desse grupo empregando gdh e tpi como genes-alvo. Para isso, amostras de fezes de 141 crianças com idade de zero a seis anos e de 18 colaboradores foram colhidas e processadas pelo método de centrífugo-flutuação e pelo kit TF-test®. Nas 141 crianças, parasitas e/ou comensais intestinais foram diagnosticados em 64 (45,4%), das amostras, sendo Giardia (22%) e Cryptosporidium (22%) os parasitas mais freqüentes. Nos funcionários, Giardia foi diagnosticada em apenas uma amostra (5,5%) e o protozoário comensal Entamoeba coli (22,2%) foi o mais prevalente. Empregando técnicas baseadas em PCR, o DNA extraído de 86 (31 amostras positivas e 55 negativas para Giardia no exame microscópico) foi amplificado e os produtos obtidos foram seqüenciados. A análise de 35 seqüências revelou a ocorrência de infecção pelos genótipos A (28,6%) e B (71,4%), subtipos AI, AII, BIII/BSI e BIV, no entanto, associações entre os genótipos e fatores de risco para a infecção não foram observadas. O alinhamento das seqüências de gdh e tpi, revelou a presença de um a 12 SNPs (Single Nucleotide Polymorphisms) em isolados dos genótipos A e B, sendo que em alguns deles, as mutações foram responsáveis por alterações nas seqüências de aminoácidos. A infecção de seis crianças de um mesmo grupo e de uma funcionária por isolados classificados como genótipo B e apresentando seqüências nucleotídicas 100% idênticas entre si sugere a ocorrência de transmissão antroponótica na população estudada. Além disso, a maior prevalência do genótipo B, grupo predominante nas infecções humanas, reforça o fato de que a transmissão... / The present study was conducted to investigate the prevalence of intestinal parasites in children and employees of a daycare center of Pratania, São Paulo State, and to evaluate the genotypes Giardia duodenalis isolates obtained from individuals in this group by using gdh and tpi genes as targets. Fecal samples of 141 children aged zero to six years and 18 employees were processed by a flotation method and the TF-Test® kit. Of the 141 children samples, parasites and/or commensal organisms were diagnosed in 64 (45.4%) samples, and Giardia (22%) and Cryptosporidium (22%) were the most frequent parasites. In employees, Giardia was diagnosed in only one sample (5.5%) and the commensal protozoan Entamoeba coli (22.2%) was the most prevalent. DNA extracted from 86 samples (31 samples positive and 55 negative for Giardia by microscopic examination) was amplified by PCR and the products were sequenced. The analysis of 35 sequences revealed the occurrence of infection with genotypes A (28.6%) and B (71.4%) subtypes AI, AII, BIII / BIV and BSI, however, associations between genotypes and risk factors for infection were not observed. The alignment of the sequences revealed SNPs (Single Nucleotide Polymorphisms) in both genotypes A and B, altering the amino acid sequence of some isolates. Among isolates identified as genotype B, six obtained from children of the same group and one from the only one employee infected with Giardia showed gdh and tpi sequences different from reference ones, but 100% identical to each other. This data is suggestive of anthroponotic transmission in the studied population. In addition this finding, the higher prevalence of genotype B, the main group associated to human infections, reinforces the fact that anthroponotic transmission has importance in collective environments that meet children at an age that they still have not practice the basic precepts of hygiene.
2

Prevalência de parasitas intestinais e caracterização genotípica de Giardia duodenalis em creche do município de Pratânia, estado de São Paulo /

David, Érica Boarato. January 2011 (has links)
Resumo: O presente estudo foi realizado para investigar a prevalência de enteroparasitas em crianças e funcionários da creche do município de Pratânia, Estado de São Paulo, e caracterizar geneticamente os isolados de Giardia duodenalis obtidos dos indivíduos desse grupo empregando gdh e tpi como genes-alvo. Para isso, amostras de fezes de 141 crianças com idade de zero a seis anos e de 18 colaboradores foram colhidas e processadas pelo método de centrífugo-flutuação e pelo kit TF-test®. Nas 141 crianças, parasitas e/ou comensais intestinais foram diagnosticados em 64 (45,4%), das amostras, sendo Giardia (22%) e Cryptosporidium (22%) os parasitas mais freqüentes. Nos funcionários, Giardia foi diagnosticada em apenas uma amostra (5,5%) e o protozoário comensal Entamoeba coli (22,2%) foi o mais prevalente. Empregando técnicas baseadas em PCR, o DNA extraído de 86 (31 amostras positivas e 55 negativas para Giardia no exame microscópico) foi amplificado e os produtos obtidos foram seqüenciados. A análise de 35 seqüências revelou a ocorrência de infecção pelos genótipos A (28,6%) e B (71,4%), subtipos AI, AII, BIII/BSI e BIV, no entanto, associações entre os genótipos e fatores de risco para a infecção não foram observadas. O alinhamento das seqüências de gdh e tpi, revelou a presença de um a 12 SNPs (Single Nucleotide Polymorphisms) em isolados dos genótipos A e B, sendo que em alguns deles, as mutações foram responsáveis por alterações nas seqüências de aminoácidos. A infecção de seis crianças de um mesmo grupo e de uma funcionária por isolados classificados como genótipo B e apresentando seqüências nucleotídicas 100% idênticas entre si sugere a ocorrência de transmissão antroponótica na população estudada. Além disso, a maior prevalência do genótipo B, grupo predominante nas infecções humanas, reforça o fato de que a transmissão... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The present study was conducted to investigate the prevalence of intestinal parasites in children and employees of a daycare center of Pratania, São Paulo State, and to evaluate the genotypes Giardia duodenalis isolates obtained from individuals in this group by using gdh and tpi genes as targets. Fecal samples of 141 children aged zero to six years and 18 employees were processed by a flotation method and the TF-Test® kit. Of the 141 children samples, parasites and/or commensal organisms were diagnosed in 64 (45.4%) samples, and Giardia (22%) and Cryptosporidium (22%) were the most frequent parasites. In employees, Giardia was diagnosed in only one sample (5.5%) and the commensal protozoan Entamoeba coli (22.2%) was the most prevalent. DNA extracted from 86 samples (31 samples positive and 55 negative for Giardia by microscopic examination) was amplified by PCR and the products were sequenced. The analysis of 35 sequences revealed the occurrence of infection with genotypes A (28.6%) and B (71.4%) subtypes AI, AII, BIII / BIV and BSI, however, associations between genotypes and risk factors for infection were not observed. The alignment of the sequences revealed SNPs (Single Nucleotide Polymorphisms) in both genotypes A and B, altering the amino acid sequence of some isolates. Among isolates identified as genotype B, six obtained from children of the same group and one from the only one employee infected with Giardia showed gdh and tpi sequences different from reference ones, but 100% identical to each other. This data is suggestive of anthroponotic transmission in the studied population. In addition this finding, the higher prevalence of genotype B, the main group associated to human infections, reinforces the fact that anthroponotic transmission has importance in collective environments that meet children at an age that they still have not practice the basic precepts of hygiene. / Orientador: Semíramis Guimarães Ferraz Viana / Coorientador: Teresa Cristina G. de Oliveira-Sequeira / Banca: Paulo Eduardo Martins Ribolla / Banca: Marcelo Urbano Ferreira / Mestre
3

Essays in empirical corporate finance and governance

Nilsson, Mattias January 2002 (has links)
Agency Costs of Controlling Minority Shareholders (coauthored with Henrik Cronqvist) estimates the agency costs of controlling minority shareholders (CMSs) using a panel of Swedish listed firms. CMSs are owners who have a control stake of the firm’s votes while owning only a minority fraction of the firm’s equity. The study documents that families in control are almost exclusively CMSs through an extensive use of dual-class shares. The results show that increased ownership of votes by a controlling owner is associated with an economically and statistically significant decrease in firm value, but that the decrease in firm value is significantly larger for firms with family CMSs than for firms with financial institutions or corporations in control. This indicates that the agency costs of family CMSs are larger than the agency costs of other controlling owners.Family Ownership, Control Considerations, and Corporate Financing Decisions: An Empirical Analysis analyzes the relation between concentrated family control and firms’ choice of capital structure for a panel of Swedish listed firms. The results suggest that the capital structure choices made by firms with families in control are influenced by the controlling families’ desire to protect their control, and that the resulting capital structures are likely to increase the agency costs of family control. The Choice between Rights Offerings and Private Equity Placements (coauthored with Henrik Cronqvist) analyzes the determinants of the choice between rights offerings and private equity placements using a sample of rights offerings and private placements made by listed Swedish firms. The results indicate that control considerations explain why firms make uninsured rights offerings. The evidence also suggest that private placements, and to some extent underwritten rights offerings, are made by potentially undervalued firms in order to overcome underinvestment problems resulting from asymmetric information about firm value. Furthermore, private placements are frequently made in conjunction with the establishment of a product market relationship between purchaser and seller, which is consistent with equity ownership reducing contracting costs in new product market relationships. Why Agency Costs Explain Diversification Discounts (coauthored with Henrik Cronqvist and Peter Högfeldt) studies diversification within the real estate industry, in which firms can diversify over property types and geographical regions. Similar to previous studies, this essay documents the existence of a diversification discount. However, the major cause of the diversification discount is not diversification per se but anticipated costs due to rent dissipation in future diversifying acquisitions. Firms expected to pursue non-focusing strategies do indeed diversify more, are valued ex ante at a 20% discount over firms anticipated to follow a focusing strategy, and are predominantly family controlled. The ex ante diversification discount is, therefore, a measure of agency costs.  The Difference in Acquirer Returns between Takeovers of Public Targets and Takeovers of Private Targets shows, for a sample of Swedish takeovers, that the average acquirer abnormal return is positive and significant when the target firm is privately held but insignificant when the target firm is listed on a stock exchange. These results are robust when controlling for sample selection problems and other variables capable of explaining acquirer returns. The evidence is consistent with greater acquirer bargaining power and resolution of information asymmetries in takeovers of private targets. / Diss. Stockholm : Handelshögskolan, 2002

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