No description available.

Köln, University, Diss., 2003.

Zugl.: München, Univ., Diss., 2007

Flammula alnicola (Fr.) Kummer, formerly called Flammula conissans Fr. sensu Ricken causes a yellow stringy butt rot of several conifers in Western Canada. It is usually of infrequent occurrence in conifers, but was found to be the most important butt rot of white spruce in the Smith - Slave Lake area of Alberta. An investigation was conducted to gain information on the biology of the fungus. The decay has a characteristic pattern caused through preference of the fungus for wood rays and early spring wood. A musty odor in decay and cultures is characteristic. The fungus invades white spruce through pressure wounds caused by root contacts but evidently does not invade recently formed wounds. The average linear rate of decay was one inch per year in two-year-old artificial infections but probably less in natural infections. The fungus decayed blocks of root and stem wood, and blocks of light and heavy density wood, slowly, but at similar rates. The occurrence of the decay was related to good sites, and non-calcareous soils with acid first mineral horizons. The mat of cultures is fine woolly, white becoming a pale yellow, growth slow. Microscopically cultures are characterized by the presence of clamp connections and allocysts. Optimum growth on malt agar occurred at 22° C. and at a pH of 4.4. Fruiting in culture was induced by aeration with nearly saturated air, a temperature of 54° F. and illumination of 8 to 30 foot candles. The fruit body of F. alnicola is a yellow mushroom which has a stipe with darker base, adnate lamellae, partial veil adhering to the edge of the pileus, hymenium without pleurocystidia; spores rusty brown, 4.5 - 5.5 x 7- 10 μovate ellipsoid, apiculate. Spores germinated on culture media only after cold treatment at -7° C. Cold treatment of spores at -18° C. inhibited germination. The fungus shows the tetrapolar type of interfertility. Parallel experiments with Flammula conissans (Fr.) Gillet were conducted to establish the two fungi as separate species. F. conissans has similar cultural characters except for a faster rate of growth and the absence of the musty odor characteristic of F. alnicola. Aeration inhibits initiation of fruiting in F. conissans. Fruit bodies are smaller, the base of the stipe is concolorous with the cap and pleurocystidia are present on the hymenium. Spores are rusty brown, 4 – 4.5 x 5.5 - 8 μ, oval oblong. F. conissans shows the tetrapolar type of fertility. Monosporous mycelia of F. alnicola and F. conissans are intersterile. F. alnicola because of its slow rate of growth and restriction to heartwood is relatively unimportant as a cause of wind throw in white spruce. / Science, Faculty of / Botany, Department of / Graduate

Techn. University, Diss., 2005--Berlin.

In this thesis, we give two simple and effective methods for constructing Kummer extensions of algebraic function fields over finite fields with many rational places. Some explicit examples are obtained after a practical search. We also study fibre products of Kummer extensions over a finite field and determine the exact number of rational places. We obtain explicit examples with many rational places by a practical search. We have a record (i.e the lower bound is improved) and a new entry for the table of van der Geer and van der Vlugt.

Marburg, Univ., Diss., 2009

Cette thèse traite du comptage d'extensions cubiques relatives. Dans le premier chapitre on traite un travail commun avec Henri Cohen. Soit k un corps de nombres. On donne une formule asymptotique pour le nombre de classes d'isomorphisme d'extensions cubiques L/k telles que la clôture galoisienne de L/k contienne une extension quadratique fixée K_2/k. L'outil principal est la théorie de Kummer. Dans le second chapitre, on suppose k un corps quadratique imaginaire (avec nombre de classes 1) et on décrit un algorithme pour énumerer toutes les classes d'isomorphisme d'extensions cubiques L/k jusqu'à une certaine borne X sur la norme du discriminant relatif.

Made available in DSpace on 2014-06-11T19:25:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-12-12Bitstream added on 2014-06-13T20:33:08Z : No. of bitstreams: 1 furtadoneto_a_me_guara.pdf: 575510 bytes, checksum: 6a1a49e71ce6fbc8113435f66d99a240 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O foco deste trabalho é o espectro de inversão da molécula de amônia, resultado do fenômeno do tunelamento quântico. Para isso, usamos um modelo simpli cado, uni- dimensional, suscetível a uma análise teórica rigorosa usando a mecânica quântica não- relativística. Dentre as diversas funções hamiltonianas já estudadas para este modelo, zemos uma rápida apreciação dos trabalhos de Cohen, Dennison-Uhlenbeck, Manning, Merzbacher e Rosen-Morse. Para um estudo mais profundo, usamos o potencial do poço duplo nito que, posteriormente, descobrimos já fora analisado por Peacock-López. Re- zemos a análise deste potencial usando um caminho diferente do realizado por aquele autor. Analisamos os casos limites para este potencial e notamos que realmente, nesses regimes, ele tende para um poço nito único ou dois poços nitos separados. Então, de- senvolvemos um software grá co centrado no pacote MINUIT, desenvolvido pelo CERN, para analisar e ajustar os parâmetros aos dados experimentais da amônia e, ao nal, comparamos os resultados obtidos com aqueles encontrados na literatura. No ajuste dos parâmetros à amônia, houve uma melhoria acentuada quando passamos de uma fórmula mais simples da massa reduzida para outra mais so sticada. No caso especí co do po- tencial de Peacock-López, a comparação revela que os nossos resultados, de uma maneira geral, são mais precisos. Nossa análise se soma àquelas que contêm uma discussão quan- titativa do potencial de poço duplo. Como parte integrante deste trabalho, uma versão unidimensional simétrica do potencial de Morse foi exatamente resolvida em termos de funções de Kummer e um par de equações transcendentes para as autoenergias. A tentativa de ajustar este resultado à molécula de amônia, porém, mostrou que os padrões de poço duplo deste potencial... / The focus of this work is the inversion spectrum of the ammonia molecule, a result of the phenomenon of quantum tunneling. For this, we use a simpli ed, one-dimensional model, amenable to a rigorous theoretical analysis using the non-relativistic quantum me- chanics. Among the various Hamiltonian functions previously studied for this model, we made a quick appraisal of the work of Cohen, Dennison-Uhlenbeck, Manning, Merzbacher and Rosen-Morse. For a deeper study, we used the nite double-well potential which, as we later discovered, had been considered by Peacock-López. We redid the analysis of this potential using a di¤erent path made by that author. We analyze the limiting cases for this potential and actually noticed that in these schemes, it tends to one nite well or two separate nite wells. So, we developed a graphical software centered on the MINUIT pack- age, developed by CERN, to analyze and adjust the parameters to the experimental data of ammonia and at the end, we compared the results with those found in the literature. In setting the parameters of ammonia, there was a marked improvement when we move from a simpler formula for the reduced mass to a more sophisticated one. In the speci c case of the potential of Peacock-López, the comparison shows that our results, in general, are more accurate and precise. Our analysis adds to those that contain a quantitative discussion of the double-well potential. As part of this work, a symmetric one-dimensional version of the Morse potential is exactly solved in terms of the Kummer functions and a pair of transcendental equations for the eigenenergies. Attempting to adjust this result to the ammonia molecule, however, showed that the double-well patterns of this potential well are irreconcilable with the energy spectrum of ammonia: Close pairs separated by long intervals

Orientador: Antonio Soares de Castro / Banca: Denis Dalmazi / Banca: Manuel Bastos Malheiro de Oliveira / Resumo: O foco deste trabalho é o espectro de inversão da molécula de amônia, resultado do fenômeno do tunelamento quântico. Para isso, usamos um modelo simpli…cado, uni- dimensional, suscetível a uma análise teórica rigorosa usando a mecânica quântica não- relativística. Dentre as diversas funções hamiltonianas já estudadas para este modelo, …zemos uma rápida apreciação dos trabalhos de Cohen, Dennison-Uhlenbeck, Manning, Merzbacher e Rosen-Morse. Para um estudo mais profundo, usamos o potencial do poço duplo …nito que, posteriormente, descobrimos já fora analisado por Peacock-López. Re- …zemos a análise deste potencial usando um caminho diferente do realizado por aquele autor. Analisamos os casos limites para este potencial e notamos que realmente, nesses regimes, ele tende para um poço …nito único ou dois poços …nitos separados. Então, de- senvolvemos um software grá…co centrado no pacote MINUIT, desenvolvido pelo CERN, para analisar e ajustar os parâmetros aos dados experimentais da amônia e, ao …nal, comparamos os resultados obtidos com aqueles encontrados na literatura. No ajuste dos parâmetros à amônia, houve uma melhoria acentuada quando passamos de uma fórmula mais simples da massa reduzida para outra mais so…sticada. No caso especí…co do po- tencial de Peacock-López, a comparação revela que os nossos resultados, de uma maneira geral, são mais precisos. Nossa análise se soma àquelas que contêm uma discussão quan- titativa do potencial de poço duplo. Como parte integrante deste trabalho, uma versão unidimensional simétrica do potencial de Morse foi exatamente resolvida em termos de funções de Kummer e um par de equações transcendentes para as autoenergias. A tentativa de ajustar este resultado à molécula de amônia, porém, mostrou que os padrões de poço duplo deste potencial... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract:The focus of this work is the inversion spectrum of the ammonia molecule, a result of the phenomenon of quantum tunneling. For this, we use a simpli…ed, one-dimensional model, amenable to a rigorous theoretical analysis using the non-relativistic quantum me- chanics. Among the various Hamiltonian functions previously studied for this model, we made a quick appraisal of the work of Cohen, Dennison-Uhlenbeck, Manning, Merzbacher and Rosen-Morse. For a deeper study, we used the …nite double-well potential which, as we later discovered, had been considered by Peacock-López. We redid the analysis of this potential using a di¤erent path made by that author. We analyze the limiting cases for this potential and actually noticed that in these schemes, it tends to one …nite well or two separate …nite wells. So, we developed a graphical software centered on the MINUIT pack- age, developed by CERN, to analyze and adjust the parameters to the experimental data of ammonia and at the end, we compared the results with those found in the literature. In setting the parameters of ammonia, there was a marked improvement when we move from a simpler formula for the reduced mass to a more sophisticated one. In the speci…c case of the potential of Peacock-López, the comparison shows that our results, in general, are more accurate and precise. Our analysis adds to those that contain a quantitative discussion of the double-well potential. As part of this work, a symmetric one-dimensional version of the Morse potential is exactly solved in terms of the Kummer functions and a pair of transcendental equations for the eigenenergies. Attempting to adjust this result to the ammonia molecule, however, showed that the double-well patterns of this potential well are irreconcilable with the energy spectrum of ammonia: Close pairs separated by long intervals / Mestre