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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

Efeito dos processos de centrifugação, diluição e descongelação sobre a qualidade do sêmen de catetos (Tayassu tajacu, Linnaeus, 1758) / Effect of the procedures for centrifugation, dilution and thawing on the quality of the semen of collared peccary (Tayassu tajacu, linnaes, 1758)

Castelo, Thibério de Souza 05 March 2010 (has links)
Made available in DSpace on 2016-08-15T20:31:37Z (GMT). No. of bitstreams: 1 ThiberioSC_DISSERT.pdf: 700205 bytes, checksum: 7a5563445307116480b9ce4be88608c4 (MD5) Previous issue date: 2010-03-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / We evaluated the effect of centrifugation and the use of Tris-based extender supplemented with different sugars as well as different rates of thawing on the kinematic pattern of motility and other characteristics of frozen-thawed semen from captive collared peccaries. Semen from 13 collared were collected by electroejaculation and evaluated subjectively for motility, vigor and by computer analysis (CASA). Other features such as sperm viability, membrane integrity and morphology of spermatozoa were also evaluated. Semen was divided into four portions: two were subjected to centrifugation and then diluted in a tris plus fructose and the other in tris supplemented with glucose, the other two forms were immediately diluted in the same way. Egg yolk (20%) and glycerol (6%) were added to all groups. The samples were frozen in liquid nitrogen and thawed using two thawing rates (37ºC/1min and 55°C/7s). The results showed a reduction in total motility immediately after the dilution using both extenders and interference in some kinematic parameters such as BCF, LIN and STR for the samples centrifuged, , in addition, an increase in the number of total and secondary morphological defects were observed in centrifuged samples, independent to the sugar used (P <0.05). No significant differences among the extenders supplemented with fructose or glucose were verified at any time (P> 0.05). Furthermore, no interaction between the supplementation of sugar and thawing rates were observed for any semen parameter evaluated (P> 0.05). In conclusion, it is not necessary to centrifuge the semen from collared prior to the procedure of freezing and thawing, which can be achieved through a Tris-based extender supplemented with either fructose or glucose, as well as using different thawing rates (37ºC/1min and 55°C/7s). / Avaliou-se o efeito da centrifugação e da utilização de diluentes a base Tris suplementados com diferentes açúcares além de diferentes taxas de descongelação sobre os padrões cinemáticos de motilidade e outras características do sêmen congeladodescongelado de catetos em cativeiro. O sêmen de 13 catetos foi coletado por eletroejaculação e avaliados subjetivamente e através de análise computadorizada (CASA) para motilidade, vigor. Outras características como viabilidade espermática, integridade da membrana e morfologia dos espermatozóides também foram avaliadas. O sêmen foi dividido em quatro alíquotas: duas foram submetidas à centrifugação e em seguida diluídas, uma em tris acrescido de frutose e a outra em tris acrescido de glicose, as outras duas forma imediatamente diluídas da mesma forma. Gema de ovo (20%) e glicerol (6%) foram adicionados para todos os grupos. As amostras foram congeladas em nitrogênio líquido e descongeladas usando duas taxas de descongelação (37ºC/1min e 55ºC/7s). Os resultados demonstraram uma redução na motilidade total imediatamente após a diluição em ambos diluentes para as amostras centrifugadas, bem como em alguns parâmetros cinemáticos como BCF, LIN e STR além do aumento no número de alterações morfológicas totais e secundarias independente do açúcar utilizado (P<0,05), tendo em vista não ter apresentado diferenças entre os diluentes suplementados com frutose ou glicose em nenhum momento (P> 0,05). Além disso, nenhuma interação entre a suplementação de açúcar e as taxas de descongelação foi observada para qualquer parâmetro seminal avaliado (P> 0,05). Em conclusão, não é necessário centrifugar o ejaculado de catetos antes dos procedimentos de congelação e descongelação, para os quais pode-se utilizar um diluente a base de Tris suplementado tanto com frutose ou glicose, bem como utilizando taxas de descongelação diferentes (37ºC/1min e 55ºC/7s).
2

Namrzavost zemin a druhotných materiálů v podloží vozovek / Frost susceptibility of soils and waste materials to pavement subgrade

Sokolová, Veronika January 2015 (has links)
Destruction of road constructions due to the frost is in locations with temperatures under the zero a problem which leads to permanent deformation. The theoretical part of this thesis deals with the freezing process of the pavement and its subgrade. It presents methods for determining the rate of frost susceptibility in both the Czech Republic and abroad. Describes the materials used in the subgrade of roads and their suitability in terms of frost susceptibility. The thesis closely examines the fly-ashes, their properties and possibilities of using in the construction industry. The practical part of the thesis focuses on the performance of direct laboratory frost heave tests, immediate bearing index tests, California bearing ratio tests and cyclic load triaxial tests to determine the modulus of elasticity. Tests are carried out on the soil, the soil mixtures with certain percentages of fly ash from different sources at the same soil treated with lime. Then the results are compared and dependence between the measured characteristics of materials is created.

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