Made available in DSpace on 2014-06-11T19:25:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-08-28Bitstream added on 2014-06-13T19:53:40Z : No. of bitstreams: 1 gasparelli_erf_me_araca.pdf: 500187 bytes, checksum: 20384c22730ccd6e17828305c437e923 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Foram acompanhados 310 parturições de receptoras, com embriões fertilizados in vivo (FV) e in vitro (FIV) da raça Nelore, para determinar os índices de partos distócicos em receptoras meio sangue das raças Braford/Nelore, Hereford/Nelore, Simental/Nelore, Red Angus/Nelore, Nelore e anelorados, com idade entre três e seis anos, assim como avaliar o estado de saúde dos bezerros obtidos por intermédio de transferência de embriões, resultantes das técnicas de fertilização in vivo (FV) ou fertilização in vitro (FIV). Observou-se a ocorrência de 38 partos distócicos (38/310) e oito abortos (8/310), dos quais cinco fetos eram oriundos da técnica de fertilização in vivo (FV) e três da técnica de fertilização in vitro (FIV). A taxa de mortalidade em animais neonatos foi de 3,4% (10/290). Os bezerros nascidos de partos distócicos mais duradouros, entre quatro e seis horas, apresentaram os maiores valores médios de freqüência respiratória. A temperatura retal foi mais elevada em animais nascidos de partos laboriosos do que naqueles nascidos de partos normais. / Three hundred and ten parturitions of receivers were accompanied, with Nellore embryos fertilized in vivo (FV) and in vitro (FIV), to determine the indices of dystocic calving in Braford/Nellore, Hereford/Nellore, Simental/Nellore, Red Angus/Nellore, Nellore and Zebu crossbreed recipients cows, aged between three and six years, as well as, to evaluate health condition of calves obtained through embryos transfer, resulting from in vivo fertilization (FV) and in vitro fertilization (FIV) techniques. The occurrence of 38 dystocic calving (38/310) and eight abortions (8/310) were observed, in which five embryos were arisen by in vivo fertilization technique (FV) and three embryos by in vitro fertilization technique (FIV). In neonate animals, the mortality rate was 3,2% (10/310). Calves born by lasting dystocic calving, between four and six hours, presented the biggest average values of respiratory frequency. Animals born by laborious calving showed higher retal temperature than those born by normal calving.

The proton magnetic resonance of tridecane and hexadeeane and their urea adducts and of some thiourea adducts has been studied as a function of temperature. It has been shown that quite considerable molecular motion can occur in the adducts even at low temperatures. The results support previous conclusions obtained by other methods. / Science, Faculty of / Chemistry, Department of / Graduate

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Nitrogen (N) fertilizer management in wheat (Triticum aestivum L.) can impact grain yield and protein. Develping strategies that improve N efficiency are needed to optimize wheat production in North Dakota. Field experiments were conducted to evaluate N stabilizers, N rate, N placement and application timing on grain yield and protein of winter and spring wheat. The timing of N release from a polymer coated urea (ESN) was also studied. Nitrogen stabilizers improved N efficency in some environments but not all. Deeper placement of urea helped reduce N losses. The closer that N fertilizer was applied to the date it was utilized by wheat usually increased protein. Nitrogen release from ESN was gradual over several months offering potential protection against N losses from a fall or spring applicaton.

Interest in the chemical constitution of montan wax began with the work of Von Boyen, who in 1901 showed montanic acid to be a constituent of the wax. In the years that followed the literature has been rich with respect to investigations of montan wax. Most of the literature concerns itself with the technology of the wax, its uses, methods of refining and purification. Much has also been written on its chemical make-up. It was the purpose of this research to explore the possibility of forming urea adducts of the normal components of montan wax, and to investigate the properties of the adducts and the waxes regenerated from the decomposed adducts.

Urea based fertilizers are susceptible to N losses through volatilization, denitrification, and leaching. A field and incubation experiment were conducted at Mississippi State between 2013 and 2015 to evaluate the effect of fertilizer stabilizers on grain yield, N use, and N transformations in various soil textures. Stabilizers were applied to liquid urea-ammonium-nitrate (UAN) solution (32%) and granular urea (46-0-0) at labeled rates for 179 and 112 kg N ha-1 for the field and incubation experiments, respectively. Grain yield and N content at tasseling and physiological maturity were measured for the field experiment. Extracts from the incubation experiment were measured for NH4+-N and NO3⁻-N concentrations. Results from the field experiment suggest greater plant N accumulation, but inconsistent yield increases with fertilizer stabilizers. Incubation results indicate fertilizer stabilizers significantly decrease the rate of N transformations. Further research is necessary to determine the effects of stabilizers over N rates and yearly environmental conditions.

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