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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

Morfologia craniana híbrida em populações humanas: uma análise morfométrica de crânios brasileiros de brancos, negros e pardos / Hybrid cranial morphology in human populations: a morphometric analysis of Brazilian skulls of whites, blacks and browns

Reis, Mariana Inglez dos 27 April 2015 (has links)
A caracterização fenotípica representa uma temática clássica na biologia evolutiva e o modo como diferentes caracteres respondem aos processos evolutivos tem sido problemática frequente em estudos envolvendo as mais diversas espécies. O presente trabalho visou investigar justamente como determinado fenótipo se comporta mediante o fluxo gênico. Primeiramente, explorou-se a possibilidade de se identificar e distinguir a partir de análises de traços craniométricos indivíduos anteriormente separados quanto a cor em três grupos: brancos, negros e pardos. Em um segundo momento, testou-se se a morfologia craniana expressa por indivíduos classificados como pardos seria intermediária em comparação com a expressa por brancos e negros. As análises estatísticas uni e multivariadas empregadas sobre os diferentes bancos de dados (dados brutos, dados das parcelas masculina e feminina separadamente, dados corrigidos para tamanho e também corrigidos para normalidade) apontaram ser possível discriminar os indivíduos previamente classificados de acordo com a cor em brancos, negros e pardos. Estes últimos, por sua vez, apresentam morfologia intermediária entre os grupos considerados parentais. Tais resultados permitem inferir que traços craniométricos, além de bons marcadores para a compreensão das relações histórico-biológicas populacionais, também seguiram o esperado como resposta ao fluxo gênico para um modelo de genética aditiva clássica segundo o qual a população híbrida apresenta frequências médias entre as populações parentais. Apesar de cor da pele e morfologia craniana representarem fenótipos com diferentes histórias evolutivas, observou-se correlação entre os dois caracteres para esta amostra, evidenciando-se que ambos representaram bons marcadores de mistura entre populações / Phenotypic characterization is a classic theme in evolutionary biology. The way different characters respond to evolutionary processes has been a frequent issue in studies involving a diverse number of species. This study aimed to investigate how a particular phenotype behaves by gene flow. First, it was explored the possibility to use analysis of craniometric traits to identify and distinguish individuals previously sorted by color into three groups: white, black and brown. Secondly, it was tested whether the cranial morphology expressed by individuals classified as brown would be intermediate compared to that expressed by whites and blacks. The univariate and multivariate statistical analysis used for the different databases (raw databases, data from male and female portions separately, data ajusted regarding size factor and normality) pointed out to be possible to discriminate individuals previously classified as white, black and brown, the latter being presented as an intermediate morphology between the considered parental groups. These results indicate that craniometric traits, besides being good markers for understanding the historical-biological population relationships, also followed as expected in response to gene flow for a classic additive genetic model, in which the hybrid population has medium frequencies between parental populations. Although skin color and cranial morphology represent phenotypes with different evolutionary histories, it was observed a correlation between the two characters for this sample, indicating that both represent good markers for mixture between populations
2

Morfologia craniana híbrida em populações humanas: uma análise morfométrica de crânios brasileiros de brancos, negros e pardos / Hybrid cranial morphology in human populations: a morphometric analysis of Brazilian skulls of whites, blacks and browns

Mariana Inglez dos Reis 27 April 2015 (has links)
A caracterização fenotípica representa uma temática clássica na biologia evolutiva e o modo como diferentes caracteres respondem aos processos evolutivos tem sido problemática frequente em estudos envolvendo as mais diversas espécies. O presente trabalho visou investigar justamente como determinado fenótipo se comporta mediante o fluxo gênico. Primeiramente, explorou-se a possibilidade de se identificar e distinguir a partir de análises de traços craniométricos indivíduos anteriormente separados quanto a cor em três grupos: brancos, negros e pardos. Em um segundo momento, testou-se se a morfologia craniana expressa por indivíduos classificados como pardos seria intermediária em comparação com a expressa por brancos e negros. As análises estatísticas uni e multivariadas empregadas sobre os diferentes bancos de dados (dados brutos, dados das parcelas masculina e feminina separadamente, dados corrigidos para tamanho e também corrigidos para normalidade) apontaram ser possível discriminar os indivíduos previamente classificados de acordo com a cor em brancos, negros e pardos. Estes últimos, por sua vez, apresentam morfologia intermediária entre os grupos considerados parentais. Tais resultados permitem inferir que traços craniométricos, além de bons marcadores para a compreensão das relações histórico-biológicas populacionais, também seguiram o esperado como resposta ao fluxo gênico para um modelo de genética aditiva clássica segundo o qual a população híbrida apresenta frequências médias entre as populações parentais. Apesar de cor da pele e morfologia craniana representarem fenótipos com diferentes histórias evolutivas, observou-se correlação entre os dois caracteres para esta amostra, evidenciando-se que ambos representaram bons marcadores de mistura entre populações / Phenotypic characterization is a classic theme in evolutionary biology. The way different characters respond to evolutionary processes has been a frequent issue in studies involving a diverse number of species. This study aimed to investigate how a particular phenotype behaves by gene flow. First, it was explored the possibility to use analysis of craniometric traits to identify and distinguish individuals previously sorted by color into three groups: white, black and brown. Secondly, it was tested whether the cranial morphology expressed by individuals classified as brown would be intermediate compared to that expressed by whites and blacks. The univariate and multivariate statistical analysis used for the different databases (raw databases, data from male and female portions separately, data ajusted regarding size factor and normality) pointed out to be possible to discriminate individuals previously classified as white, black and brown, the latter being presented as an intermediate morphology between the considered parental groups. These results indicate that craniometric traits, besides being good markers for understanding the historical-biological population relationships, also followed as expected in response to gene flow for a classic additive genetic model, in which the hybrid population has medium frequencies between parental populations. Although skin color and cranial morphology represent phenotypes with different evolutionary histories, it was observed a correlation between the two characters for this sample, indicating that both represent good markers for mixture between populations
3

Synthesis of Hybrid Inorganic-Organic Microparticles

Joshi, Shreyas 20 October 2021 (has links)
The self-assembly of isotropic and anisotropic colloidal particles into higher-ordered structures has been of great interest recently due to the promise of creating metamaterials with novel macroscopic properties. The physicochemical properties of these metamaterials can be tailored to achieve composites with tunable functionalities. The formation of these metamaterials can be used as a pathway to emulating advanced biological systems. In particular, synthetically mimicking the surface of a moth’s eye, which consists of arrays of ellipsoidal protuberances, can be used as a strategy for fabricating antireflective coatings. To enable this technology, it is necessary to design a synthesis scheme that produces micron-sized composite particles with tunable refractive index. In the future, the resulting composite microparticles can then undergo geometric and spatial modifications to form self-assemblies that have unique macroscopic material properties. This research work delineates a strategy of developing microparticles with a hybrid configuration that constitutes an inorganic and an organic part. The inorganic part comprises ~30 nm diameter titania (TiO2) nanoparticles, which are embedded within an organic polymer particle comprised of diethyl methylene malonate polymer [p(DEMM)]. Anionic polymerization is modified to controllably incorporate TiO2 nanoparticles into the polymer matrix. A design of experiments was identified and carried out to identify the major process variables that influence the final particle size. In particular, since DEMM polymerization may be initiated entirely by the presence of hydroxyl anions, pH was found to control the final overall particle diameter between 300 nm and 1 micrometer. The overall inorganic particle loading can be readily modified and is confirmed by thermogravimetric analysis, allowing for the desired macroscopic refractive index to be controlled. Light scattering, scanning electron microscopy and zeta potential analysis reveals that the colloidal stability of the hybrid microparticles is dependent on the ligand coating the inorganic constituent. In addition, this synthetic scheme is applied to different inorganic constituents that have interesting functionalities, such as fluorescent CdTe quantum dots, in order to show the methods versatility method to produce composite particles for a wide spectrum of applications. These initial investigations provide a the synthetic groundwork to evaluating the coating properties of the microparticles and their self-assembly into novel materials in the future.

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