Fertilization and cleavage of bovine embryos depend not only on maternal involvement, but also on the paternal contributions that involve more than just providing the haploid male genome. Therefore, the overall objective of this project was to determine the impact of morphologically abnormal spermatozoa on fertilization, subsequent embryonic development, and embryo quality at the cellular level. Four experiments used morphologically abnormal semen samples collected and cryopreserved from four Holstein bulls before (Pre) and after a scrotal insulation (PI) period of 48 h. Zygotes were cultured for 8 d when a developmental score was assigned to each embryo; subpopulations were subjected to either the TUNEL or caspase assays to determine apoptosis. In the final experiment pronuclear decondensation for presumptive zygotes was evaluated by differential interference contrast microscopy at 3 h time intervals from 6 to 18 h post in vitro insemination (hpi). Morphological evaluation of semen samples revealed a decrease (P < 0.01) in the percentages of normal spermatozoa in the PI samples in comparison with the Pre samples for Bulls I and Bull III (74 to 22.3% and 67.7 to 0.5 %, respectively) and the scrotal insulation effects persisted from the time of cleavage through blastocyst formation for Bulls I and III and corresponded with a similar decrease in blastocyst development for PI samples in experiment 1 regardless of which semen separation method was used. Likewise, the overall pronuclear decondensation rate for the PI zygotes of Bull I and III showed no increase over time and remained predominantly at PN1 stage (1.5 ± 0.17; 1.8 ± 0.22, respectively). In contrast, the development for Bull II and Bull IV were unaffected. The embryo quality assessment revealed that the caspase intensity increased significantly for both Bull I (217 ± 147) and Bull III (229 ± 98) for the PI embryo groups compared to those of Bull II (98 ± 115) and Bull IV (90 ± 111). In conclusion, the tested separation methods used seemed inadequate in their ability to provide potentially competent sperm for IVF. The decrease in embryonic development appears to be multifaceted and related to the changes in head shape morphology and we suggest the failure in normal pronuclear formation is associated with an absence of normal decondensation of the penetrating spermatozoon. The inability to consistently measure apoptosis in early stage embryos complicates the assessment of differences in embryo quality. These observations support the hypothesis of uncompensable seminal traits in IVF with abnormal spermatozoa and provide compelling evidence that the effect of morphologically abnormal spermatozoa occurred prior to cleavage, thus is manifested during the early stages of fertilization. / Ph. D.

The aim of the work was to evaluate the quality of boar ejaculate in terms of sperm morphology and the influence on fertility of sows. The data came from 58 sperm collections from 8 boars of one line. The boars were housed in the semen collection centre under the same conditions and were in age from 11 to 21 months. In the ejaculate analysis, the evaluation of the pathologically changed sperms was performed by determining the frequency of the finding of individual morphological changes. To evaluate the effect of semen on the litter size, data from 123 successful inseminations and subsequent births were processed. The results showed that boars in most cases produced ejaculate with an average volume with a lower sperm concentration. The incidence of morphologically abnormal sperms was normal for almost all boars. The most common sperm abnormalities were immature sperms and defects of sperm flagella. It was confirmed that more piglets were born after using insemination doses made from sperm ejaculate with the higher sperm count. Furthermore, when using ejaculate with a morphologically abnormal sperm count below 15%, more piglets were born than when the sperm count was 1525%. In the case of immature sperms, a negative correlation with the number of born piglets has been proven.

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<p> This dissertation is concerned with establishing the conditions under which planar phase interfaces are morphologically unstable during phase transformations in isothermal ternary systems. First, linear perturbation methods are employed in a detailed treatment of precipitatematrix interface stability for dilute ternary systems. Following this, the stability of the planar interface in a two-phase ternary diffusion couple is examined with the aid of perturbation theory. An experimental investigation into the stability of <alpha>-<beta> phase interfaces in the Cu-Zn-Ni system at 775°C is described. The results of this experimental study are shown to be in good agreement with the earlier theoretical predictions. </p> / Thesis / Doctor of Philosophy (PhD)

The dissertation examines mainly segmental assimilatory processes of Xhosa phonology within the dependency framework. This model is a multi-faceted approach which involves hierarchical organisation of features into larger constituents known as gestures. The analysis includes an elementary historical background to the development of phonological theory with emphasis on the shift from traditional linear approaches to modern non-linear models, as well as a shift from derivational theories to representational frameworks. An exploration of the phonetics/phonology interface through the application of gestures is considered an advantage of using the dependency framework over other theories of phonology. The focus of the dissertation is the description of phonetically-motivated and morphologically-motivated Xhosa phonological processes. A brief exposition of the use of the dependency framework in non-assimilatory Xhosa phonological processes is given as a possible recommendation in the conclusion of the dissertation. / Language Education, Arts and Culture / M.A. (African Languages)

The dissertation examines mainly segmental assimilatory processes of Xhosa phonology within the dependency framework. This model is a multi-faceted approach which involves hierarchical organisation of features into larger constituents known as gestures. The analysis includes an elementary historical background to the development of phonological theory with emphasis on the shift from traditional linear approaches to modern non-linear models, as well as a shift from derivational theories to representational frameworks. An exploration of the phonetics/phonology interface through the application of gestures is considered an advantage of using the dependency framework over other theories of phonology. The focus of the dissertation is the description of phonetically-motivated and morphologically-motivated Xhosa phonological processes. A brief exposition of the use of the dependency framework in non-assimilatory Xhosa phonological processes is given as a possible recommendation in the conclusion of the dissertation. / Language Education, Arts and Culture / M.A. (African Languages)