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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

Regulation of follicular wave pattern in cattle

Jaiswal, Rajesh Shriniwas 04 September 2007
The wave-like developmental pattern of follicles ≥1 mm in temporal relationship with follicle stimulating hormone (FSH) and the existence of 2- and 3-waves of follicular development during an interovulatory interval (IOI) have been clearly defined in cattle. However, information about the developmental pattern of antral follicles <1 mm and the repeatability of the wave pattern (2- or 3-wave IOI) is lacking. Using approaches such as immunization against GnRH (to suppress circulating concentrations of FSH) and histomorphometric study of ovarian tissues collected from cyclic heifers on different days after ovulation, the developmental pattern of antral follicles <1 mm and the role of FSH in their development were studied in heifers. Ultrasonographically acquired follicular data were used to determine the repeatability of 2- and 3-wave patterns and the effect of season on the wave patterns. The ovulatory follicle in 3-wave IOI is exposed to a shorter term high-progesterone environment than that of 2-wave IOI, and it has been argued that the less-aged ovulatory follicle of 3-wave IOI yields a more fertile oocyte than the 2-wave IOI. The developmental competence of oocytes in preovulatory follicles of 2- versus 3-wave IOI was compared using in vivo environments created to mimic short-term low- and high-progesterone environments similar to 2- and 3-wave IOI, respectively. The developmental competence of oocytes in persistent dominant-type follicles was also determined.<p>The vaccination against GnRH attenuated FSH surges but did not suppress the basal circulating concentrations of FSH. The attenuation of FSH surges suppressed the wave-like emergence of follicles ≥4 mm but not of the antral follicles <4 mm. The study revealed an inverse relationship between the mean and peak circulating concentrations of FSH and the number of follicles recruited into ≥1 mm size category. Histomorphometric study revealed that antral follicles <1 mm developed in a wave-like fashion in response to a rise in the circulating concentrations of FSH. After treatment with exogenous FSH, the growth rate of follicles in GnRH-immunized heifers was similar to controls. <p>The duration of IOI was predictive of the wave pattern (i.e., 2- or 3-wave IOI), and the pattern was repeatable within individuals throughout the year. The dominant follicle of Wave 1 in 2-wave IOI had a longer duration of dominance than in 3-wave IOI. Hence, the dominant follicle of Wave 1 may have a primary role in the regulation of 2- and 3-wave patterns. Greater attrition of follicles in 3-wave IOI, due to the emergence of an extra wave compared to 2-wave IOI, may contribute to earlier follicular depletion and onset of reproductive senescence in heifers with primarily a 3-wave pattern. The fertilization capacity of oocytes that were exposed to the short-term low-progesterone environment (i.e., similar to the early growing phase of the ovulatory follicle of 3-wave IOI) was increased, but the developmental competence post-fertilization was not different from oocytes that were exposed to a short-term high-progesterone environment (i.e., similar to the early growing phase of preovulatory follicle of 2-wave IOI). Multiple follicles developed under the prolonged-low progesterone environment, but failed to ovulate.
2

Regulation of follicular wave pattern in cattle

Jaiswal, Rajesh Shriniwas 04 September 2007 (has links)
The wave-like developmental pattern of follicles ≥1 mm in temporal relationship with follicle stimulating hormone (FSH) and the existence of 2- and 3-waves of follicular development during an interovulatory interval (IOI) have been clearly defined in cattle. However, information about the developmental pattern of antral follicles <1 mm and the repeatability of the wave pattern (2- or 3-wave IOI) is lacking. Using approaches such as immunization against GnRH (to suppress circulating concentrations of FSH) and histomorphometric study of ovarian tissues collected from cyclic heifers on different days after ovulation, the developmental pattern of antral follicles <1 mm and the role of FSH in their development were studied in heifers. Ultrasonographically acquired follicular data were used to determine the repeatability of 2- and 3-wave patterns and the effect of season on the wave patterns. The ovulatory follicle in 3-wave IOI is exposed to a shorter term high-progesterone environment than that of 2-wave IOI, and it has been argued that the less-aged ovulatory follicle of 3-wave IOI yields a more fertile oocyte than the 2-wave IOI. The developmental competence of oocytes in preovulatory follicles of 2- versus 3-wave IOI was compared using in vivo environments created to mimic short-term low- and high-progesterone environments similar to 2- and 3-wave IOI, respectively. The developmental competence of oocytes in persistent dominant-type follicles was also determined.<p>The vaccination against GnRH attenuated FSH surges but did not suppress the basal circulating concentrations of FSH. The attenuation of FSH surges suppressed the wave-like emergence of follicles ≥4 mm but not of the antral follicles <4 mm. The study revealed an inverse relationship between the mean and peak circulating concentrations of FSH and the number of follicles recruited into ≥1 mm size category. Histomorphometric study revealed that antral follicles <1 mm developed in a wave-like fashion in response to a rise in the circulating concentrations of FSH. After treatment with exogenous FSH, the growth rate of follicles in GnRH-immunized heifers was similar to controls. <p>The duration of IOI was predictive of the wave pattern (i.e., 2- or 3-wave IOI), and the pattern was repeatable within individuals throughout the year. The dominant follicle of Wave 1 in 2-wave IOI had a longer duration of dominance than in 3-wave IOI. Hence, the dominant follicle of Wave 1 may have a primary role in the regulation of 2- and 3-wave patterns. Greater attrition of follicles in 3-wave IOI, due to the emergence of an extra wave compared to 2-wave IOI, may contribute to earlier follicular depletion and onset of reproductive senescence in heifers with primarily a 3-wave pattern. The fertilization capacity of oocytes that were exposed to the short-term low-progesterone environment (i.e., similar to the early growing phase of the ovulatory follicle of 3-wave IOI) was increased, but the developmental competence post-fertilization was not different from oocytes that were exposed to a short-term high-progesterone environment (i.e., similar to the early growing phase of preovulatory follicle of 2-wave IOI). Multiple follicles developed under the prolonged-low progesterone environment, but failed to ovulate.
3

Developmental pattern of the small (1-3 mm) follicles in cattle

Jaiswal, Rajesh Shriniwas 05 January 2004
Much has been improved in the basic and applied aspect of female reproduction after understanding of the wave-like developmental pattern of follicles ¡Ý4 mm. However, it is speculated that the understanding of the developmental pattern of small follicles <4 mm may bring about efficient management of ovarian functions for essential reproductive interventions. Present studies were therefore, carried out to characterize the developmental pattern of 1-3 mm follicles in cattle using ultrasonography and to validate a method to histologically characterize the developmental pattern of follicles <1 mm using non-serial data. Transrectal ultrasonography was used once daily (n=18 Hereford-cross heifers) to examine changes in the diameter of follicles ¡Ý1 mm for one interovulatory interval (IOI), as well as every 6 h (n = 9 Hereford-cross cows) from 5 to 13 days after ovulation to encompass emergence of Wave 2. A periodic shift in the peak number (P < 0.05) of 1-3 mm and ¡Ý4 mm follicles and a significant inverse relationship (P < 0.05) between them suggested a wave-like developmental pattern. The number of 1-3 mm follicles detected in anovulatory waves did not differ (P = 0.53) between 2- versus 3-wave IOIs. A difference (P < 0.05) was noticed between anovulatory and ovulatory waves in 3-wave IOIs but not (P = 0.63) in 2-wave IOIs. The future dominant follicle was identified at 1 mm and was found to emerge 6-12 h earlier than the largest subordinate follicle (P < 0.01). Emergence of the future dominant (r = 0.71) and 1st subordinate (r = 0.78) follicles was temporally associated (P < 0.05) with a rise in circulating concentrations of FSH. <p> The developmental pattern of follicles not detectable by ultrasonography (<1 mm) may be assessed histologically by examining the ovaries from different animals on different days (i.e., non-serial method) using follicle diameter or number profiles. A data set (n = 56 heifers) of follicles ¡Ý4 mm was tabulated in a serial (same set of heifers each day; n = 7/day, N = 7) and non-serial (different set of heifers each day; n = 7/day, N = 56) manner for number and diameter profiles around emergence of the first follicular wave. Profiling of serial and non-serial data (serial and non-serial methods) revealed a change in the number of follicles (4-5 mm, 6-8 mm, ¡Ý9 mm) over days (P < 0.01), but the effect of method and the day-by-method interaction were not different (P > 0.28). Similarly, the diameter of the dominant and first 2 subordinate follicles changed over days (P < 0.01), but the effect of method and the day-by-method interaction were not different (P > 0.06), indicating that non-serial data provide wave-like profile of follicles. <p> In conclusion, the hypothesis that follicles 1-3 mm develop in a wave-like manner was supported, and a new non-serial method was validated for the study of follicle dynamics using non-serial (e.g. histologic) data.
4

Developmental pattern of the small (1-3 mm) follicles in cattle

Jaiswal, Rajesh Shriniwas 05 January 2004 (has links)
Much has been improved in the basic and applied aspect of female reproduction after understanding of the wave-like developmental pattern of follicles ¡Ý4 mm. However, it is speculated that the understanding of the developmental pattern of small follicles <4 mm may bring about efficient management of ovarian functions for essential reproductive interventions. Present studies were therefore, carried out to characterize the developmental pattern of 1-3 mm follicles in cattle using ultrasonography and to validate a method to histologically characterize the developmental pattern of follicles <1 mm using non-serial data. Transrectal ultrasonography was used once daily (n=18 Hereford-cross heifers) to examine changes in the diameter of follicles ¡Ý1 mm for one interovulatory interval (IOI), as well as every 6 h (n = 9 Hereford-cross cows) from 5 to 13 days after ovulation to encompass emergence of Wave 2. A periodic shift in the peak number (P < 0.05) of 1-3 mm and ¡Ý4 mm follicles and a significant inverse relationship (P < 0.05) between them suggested a wave-like developmental pattern. The number of 1-3 mm follicles detected in anovulatory waves did not differ (P = 0.53) between 2- versus 3-wave IOIs. A difference (P < 0.05) was noticed between anovulatory and ovulatory waves in 3-wave IOIs but not (P = 0.63) in 2-wave IOIs. The future dominant follicle was identified at 1 mm and was found to emerge 6-12 h earlier than the largest subordinate follicle (P < 0.01). Emergence of the future dominant (r = 0.71) and 1st subordinate (r = 0.78) follicles was temporally associated (P < 0.05) with a rise in circulating concentrations of FSH. <p> The developmental pattern of follicles not detectable by ultrasonography (<1 mm) may be assessed histologically by examining the ovaries from different animals on different days (i.e., non-serial method) using follicle diameter or number profiles. A data set (n = 56 heifers) of follicles ¡Ý4 mm was tabulated in a serial (same set of heifers each day; n = 7/day, N = 7) and non-serial (different set of heifers each day; n = 7/day, N = 56) manner for number and diameter profiles around emergence of the first follicular wave. Profiling of serial and non-serial data (serial and non-serial methods) revealed a change in the number of follicles (4-5 mm, 6-8 mm, ¡Ý9 mm) over days (P < 0.01), but the effect of method and the day-by-method interaction were not different (P > 0.28). Similarly, the diameter of the dominant and first 2 subordinate follicles changed over days (P < 0.01), but the effect of method and the day-by-method interaction were not different (P > 0.06), indicating that non-serial data provide wave-like profile of follicles. <p> In conclusion, the hypothesis that follicles 1-3 mm develop in a wave-like manner was supported, and a new non-serial method was validated for the study of follicle dynamics using non-serial (e.g. histologic) data.
5

Application of the Wavelet Transform for EMG M-Wave Pattern Recognition

Salvador, Jillian 10 1900 (has links)
<p> An investigation as to the appropriateness of the wavelet transform for surface electromyography (EMG) M-wave pattern recognition is described. The M-waves are obtained by stimulating the median nerve at the wrist to activate the motor units. Surface electrodes and a graded stimulus amplitude are used. The resulting M-waves are classified using both wavelet vectors and the traditional power spectral coefficients as features sets in the pattern recognition scheme. A novel system was developed to obtain M-wave collections from subjects in the laboratory and to perform both real-time and offline analysis.</p> <p> The results obtained from the left and right thenar muscles of 4 healthy females and 2 healthy males are presented. These results are further analyzed offline to determine the effects of a changing discriminatory threshold for both wavelet and power spectral pattern recognition techniques. In addition, intra-class and inter-class Euclidean distances are shown for the set of unique M-waves derived from using the different feature sets. A time-invariant wavelet transform is implemented to improve classification by eliminating errors due to latency shifts.</p> <p> The results show that the number of unique M-waves obtained usmg wavelet features is less sensitive to a variation in discriminatory threshold. It may be concluded that a wavelet based feature set shows slight improvement in M-wave pattern classification. The time-invariant wavelet offers further accuracy.</p> / Thesis / Master of Applied Science (MASc)
6

Estimativa do fator de forma e da resistência ao avanço de embarcações através da dinâmica dos fluidos computacional. / Estimate of the form factor and the resistance of ships through the computational fluid dynamics.

Araujo, Marcos Felipe Bettini Pereira de 12 December 2013 (has links)
Este trabalho discute o efeito da escala na obtenção do fator de forma de embarcações e avalia a estimativa de resistência ao avanço e o padrão de ondas gerado pelo movimento relativo entre o fluido e o casco, através de análises computacionais. A estimativa adequada do fator de forma é importante para a determinação da resistência do casco na escala real, possibilitando o dimensionamento do sistema propulsivo, isto é, motor e hélice. Tradicionalmente o valor do fator de forma é obtido experimentalmente através de ensaios de reboque de modelos em escala reduzida. Observa-se na maioria dos laboratórios, que durante os testes o valor do fator de forma é adotado como constante, independentemente de Froude e Reynolds, conforme proposto de ITTC. É apresentada uma alternativa computacional para a determinação do fator de forma. Para tal, utiliza-se a metodologia double-model nas simulações relativas ao casco adotado, em que se obtém os coeficientes de resistência viscosa, enquanto que as linhas de correlação da ITTC\'57, Grigson e Schoenherr, além das simulações de arrasto de placas planas, calculam os coeficientes de resistência friccional. Da relação entre os coeficientes viscosos e friccionais encontra-se a tendência do fator de forma em função do número de Reynolds, considerando Froude constante. Os valores de resistência ao avanço obtidos nas simulações são comparados com os dados experimentais disponibilizados, assim como o padrão de ondas gerado, exemplificando como as ferramentas computacionais podem ser aplicadas de maneira vantajosa, uma vez que os resultados numéricos trazem boas correspondências com aqueles obtidos em tanques de provas e são obtidos mais rapidamente com menor custo. Também são apresentadas, brevemente, algumas descrições matemáticas que são utilizadas no método dos volumes finitos. / This work discusses the effect of scale in obtaining the form factor of ships and evaluates the estimated resistance and wave pattern generated by the relative motion between the fluid and the hull, through computational analyzes. A suitable estimate of the form factor is important for determining the resistance of the hull in full scale, enabling the sizing of the propulsion system, ie, engine and propeller. Traditionally the value of the form factor is obtained experimentally by towing tests of reduced scale models. It is observed in most laboratories that during testing the value of the form factor is assumed to be constant, regardless of Froude and Reynolds, as proposed by the ITTC. An alternative computation for determining the form factor is presented. For this purpose, the double-model method is used to simulate resistance tests of the adopted hull, in which the coefficients of viscous resistance are obtained. Meanwhile the coefficients of frictional resistance are calculated by the ITTC\'57, Grigson and Schoenherr correlation lines, and by the simulation of flat plates. The relationship between the viscous and frictional coefficients show the trend of the form factor as a function of Reynolds number, considering Froude constant. The resistance values obtained in the simulations are compared to experimental data available, as well as the pattern of waves, illustrating how computational tools can be applied advantageously, that is, provides similar results to those obtained in the laboratory, but quickly and at lower cost. Briefly are also presented some mathematical descriptions that are used in the finite volume method.
7

Estimativa do fator de forma e da resistência ao avanço de embarcações através da dinâmica dos fluidos computacional. / Estimate of the form factor and the resistance of ships through the computational fluid dynamics.

Marcos Felipe Bettini Pereira de Araujo 12 December 2013 (has links)
Este trabalho discute o efeito da escala na obtenção do fator de forma de embarcações e avalia a estimativa de resistência ao avanço e o padrão de ondas gerado pelo movimento relativo entre o fluido e o casco, através de análises computacionais. A estimativa adequada do fator de forma é importante para a determinação da resistência do casco na escala real, possibilitando o dimensionamento do sistema propulsivo, isto é, motor e hélice. Tradicionalmente o valor do fator de forma é obtido experimentalmente através de ensaios de reboque de modelos em escala reduzida. Observa-se na maioria dos laboratórios, que durante os testes o valor do fator de forma é adotado como constante, independentemente de Froude e Reynolds, conforme proposto de ITTC. É apresentada uma alternativa computacional para a determinação do fator de forma. Para tal, utiliza-se a metodologia double-model nas simulações relativas ao casco adotado, em que se obtém os coeficientes de resistência viscosa, enquanto que as linhas de correlação da ITTC\'57, Grigson e Schoenherr, além das simulações de arrasto de placas planas, calculam os coeficientes de resistência friccional. Da relação entre os coeficientes viscosos e friccionais encontra-se a tendência do fator de forma em função do número de Reynolds, considerando Froude constante. Os valores de resistência ao avanço obtidos nas simulações são comparados com os dados experimentais disponibilizados, assim como o padrão de ondas gerado, exemplificando como as ferramentas computacionais podem ser aplicadas de maneira vantajosa, uma vez que os resultados numéricos trazem boas correspondências com aqueles obtidos em tanques de provas e são obtidos mais rapidamente com menor custo. Também são apresentadas, brevemente, algumas descrições matemáticas que são utilizadas no método dos volumes finitos. / This work discusses the effect of scale in obtaining the form factor of ships and evaluates the estimated resistance and wave pattern generated by the relative motion between the fluid and the hull, through computational analyzes. A suitable estimate of the form factor is important for determining the resistance of the hull in full scale, enabling the sizing of the propulsion system, ie, engine and propeller. Traditionally the value of the form factor is obtained experimentally by towing tests of reduced scale models. It is observed in most laboratories that during testing the value of the form factor is assumed to be constant, regardless of Froude and Reynolds, as proposed by the ITTC. An alternative computation for determining the form factor is presented. For this purpose, the double-model method is used to simulate resistance tests of the adopted hull, in which the coefficients of viscous resistance are obtained. Meanwhile the coefficients of frictional resistance are calculated by the ITTC\'57, Grigson and Schoenherr correlation lines, and by the simulation of flat plates. The relationship between the viscous and frictional coefficients show the trend of the form factor as a function of Reynolds number, considering Froude constant. The resistance values obtained in the simulations are compared to experimental data available, as well as the pattern of waves, illustrating how computational tools can be applied advantageously, that is, provides similar results to those obtained in the laboratory, but quickly and at lower cost. Briefly are also presented some mathematical descriptions that are used in the finite volume method.

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