Thesis (Ph. D.)--Oregon State University, 1968. / Typescript (photocopy). Includes bibliographical references (leaves 57-58). Also available on the World Wide Web.

Orientador: Carminda da Cruz Landim / Banca: Foued Salmen Espindola / Banca: Mario Sergio Palma / Banca: Klaus Hartmann Hartfelder / Banca: Maria Claudia Colla Ruvolo Takasusuki / Resumo: Apis mellifera é um organismo de grande interesse para estudos neurobiológicos, pois além de apresentar um cérebro estruturalmente simples, se comparado ao dos vertebrados, apresenta características próprias relacionadas ao comportamento social, com capacidade de memória e aprendizagem. As colônias destas abelhas são constituídas por machos e fêmeas, as fêmeas dividindo-se em duas castas, operárias e rainhas. Sabendo-se que as castas e os machos de A. mellifera apresentam morfologia, fisiologia e padrões comportamentais bastante distintos que, por sua vez, estão, em boa parte representados no polimorfismo cerebral, o presente trabalho visou desvendar como essas diferenças se estabelecem a partir do cérebro larval, basicamente igual para todos. Sendo A. mellifera uma espécie holometábola a transformação das estruturas larvais para as dos adultos ocorre durante a metamorfose, ou seja, durante a pupação. Para melhor compreensão, o estudo iniciou-se com a caracterização das diferenças morfológicas entre os cérebros de operárias, rainhas e machos recém emergidos. A partir da verificação de quais eram as estruturas que mais se diferenciavam entre as classes de indivíduos que compõem a colônia, foram escolhidas para ter sua diferenciação acompanhada os corpos pedunculados, os lobos ópticos e a "pars intercerebralis" no protocérebero e os lobos antenais no deutocérebro. Dessas estruturas foi feito um estudo comparativo entre operárias, rainhas e zangões usando preparações para microscopia de luz, mensurações da área ocupada por alguns de seus componentes, estudos estruturais de outros, bem como uma estimativa das taxas de multiplicação, e mortes celulares com técnicas citoquímicas e imunocitoquímicas. Esses estudos foram iniciados com larvas no último estágio larval... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Apis mellifera is an interesting model to neurobiological studies due to the simplicity of its brain commanding the complex behaviors demanded by the eusocial relationships and its capacity of learning and memorizing. The colonies of this bee consist of males and females. The females are differentiated in two castes: workers and queens. The castes and males from A. mellifera have distinct morphology, physiology and behavior correlated with their functions in the society and represented by some brain polymorphism. In this context the aim of the present study was clear up how the adult brain differences are established parting from the larval brain basicalIy equal to alI kinds of individuaIs. A. melliftra is a holometabolous insect and therefore, the change of the larval structures to the adult ones occurs during pupation or metamorphosis. In order to have a better vision of the differences found among the adult brains. was done a comparative morphological study of the brain from newly emerged workers, queens and males. The results showed that the brain structures more distinct among the individual classes were the mushroom bodies, optic lobes and "pars intercerebralis" from the protocerebrum and the antennal lobes from the deutocerebrum. Those were choose for have their differentiation accompanied during metamorphosis. Comparative studies of the structures among workers, queens and males were done using light and electronic microscopy, measuring the areas occupied from some of their components and estimative of the rates of mitosis and cell death using cytochemical and immuno-histochemical techniques. These studies started in the last larval instar and continued in pre-pupae, white, pink, brown, and black eyed pupae until black body pupae. Besides a search for differential protein expression among the individual classes whole brain was done... (Complete abstract click electronic access below) / Doutor

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Let f(z) be a complex-valued function of the complex variable z which is regular at the origin, has radius of convergence R > 1 , and satisfies the condition f(1) = 1 . If we write [ equation omitted ]and [ equation omitted ], n=0,1,2,..., the matrix [ equation omitted ] leads to a summation method generally known as a Sonnenschein method. The utility of these methods lies in the fact that much can be said about them simply from a knowledge of the function f(z) . In the present work we are concerned with the three methods associated with the three functions f(z) = (1-r) + rz , f(z) = (1-r)+rz² and f(z) = (1-r)z + rz³ where r≠ 0 is an arbitrary complex parameter (generally, 0 < r < 1). The method based on the function (1-r) + rz leads to the well-known Euler-Knopp method which has already been extensively studied. We show that there exist simple recursion relations between the various rows of the matrix F and we make a detailed study of the domain Dᵣ on which these methods sum the geometric series [ equation omitted ].A more general sub-class of Sonnenschein methods called the (E,r,α,β) methods is then defined and some of the well-known theorems applicable to the (E,r) method are shown to hold for this sub-class. The practical application of the above three methods to the two- and three-body problems of classical mechanics forms the major portions of Chapters II and III . Much use is made in these chapters of a theorem, stated in Chapter I , which allows us to construct a domain Dr(a) on which one of the above methods sums an arbitrary function a(z) regular at the origin. On the limited Intervals for which the above methods are applicable, it is shown that they provide effective methods for obtaining the solution to the two-and three-body problems. Comparison is always made with similar results obtained by V. A. Brumberg and it is shown that the methods used here have certain advantages over his. The Sundman series for the three-body problem are also set up and utilized. Although the series are not very effective, the convergence is not as bad as is generally supposed. An interesting argument based on numerical evidence shows that the width of the strip about the real axis, in which the solution to the regularized three-body problem is known to be analytic, is not as narrow as Sundman's estimates give. Finally, a theorem is proved for the problem of the motion of a heavy rigid body about a fixed point showing that this problem can be treated in the complex plane in the same way as the two-body problem and regularized three-body problem. / Science, Faculty of / Mathematics, Department of / Graduate

Introduction: Exposure to hypoxia may alter substrate utilization through diverse mechanisms. Acute hypoxia is known to increase circulating nonesterified fatty acid (NEFA) levels and reduce systemic sensitivity to insulin. The hepatic fate of NEFA is dictated by major pathways such as esterification to triglycerides and complete/partial oxidation, the latter leading to ketogenesis. To our knowledge, the effect of hypoxia on ketogenesis, more specifically ß-hydroxybutyrate (ßOHB), remains unknown in humans. Moreover, adipose tissue is a significant site of NEFA liberation into circulation, and insulin inhibits this process. Under acute hypoxia, systemic insulin resistance develops, and the suppression of lipolysis is impeded. Therefore, the objective of this study was to determine the effect of acute hypoxia on plasma circulating ßOHB levels. Furthermore, to better understand how hypoxic and prandial conditions may modulate plasma NEFA and ketonemia, we calculated the βOHB:NEFA ratio and the adipose tissue insulin resistance index (Adipo-IR), which respectively gives indications of the partial hepatic oxidation of NEFA and the adipose tissue insulin sensitivity. Methods: Plasma samples from 3 different randomized crossover studies were retrospectively assessed for ßOHB concentrations. In the first study, 14 healthy men (23 ± 3.5 years) were exposed to 6 hours of normoxia or intermittent hypoxia (IH) (15 hypoxic events per hour) following an isocaloric meal (IH-Fed). In the second study, 10 healthy men (26 ± 5.6 years) were exposed to 6 hours of continuous normobaric hypoxia (CH) (FiO2= 0.12) or normoxic conditions in the fasting state (CH-Fasted). In the third study, 9 healthy men (24 ± 4.5 years) were exposed to 6 hours of CH in a constant prandial state. ßOHB, NEFA and insulin levels were measured during all sessions (CH-Fed). The adipose tissue insulin resistance index (Adipo-IR) was also calculated from NEFA and insulin levels. Results: In study 1 (IH-Fed), ßOHB and NEFA levels tended to be greater over 6 hours of IH (condition x time interaction, p = 0.108 and p = 0.062, respectively) compared to normoxia. In study 2 (CH-Fasted), ßOHB and NEFA levels increased over time in both experimental conditions, and this effect tended to be greater under CH (condition x time interaction, p = 0.070 and p = 0.046, respectively). In study 3 (CH-Fed), ßOHB levels slightly increased up to 180 min before falling back to initial concentrations by the end of the protocol in both normoxia and CH (p = 0.062), while NEFA slightly increased under CH (p = 0.006). Adipo-IR tended to increase after 6 hours of hypoxia compared to normoxia in the first two studies (main effect of condition, p = 0.024; p = 0.097, respectively), and significantly increased over time under hypoxia in CH-Fed (condition x time interaction, p = 0.004). Conclusion: Acute normobaric hypoxia exposure significantly increases plasma ßOHB concentrations over time in healthy men. The stimulating effect of hypoxia on plasma ßOHB levels is however attenuated during postprandial and postprandial states. Contribution to advancement of knowledge: To our knowledge, this research provides some of the first evidence that an acute exposure to hypoxia increases plasma ßOHB levels in humans. It also reveals potential underlying mechanism that modulate ketogenesis upon hypoxia exposure. Overall, this thesis provides further insights into the homeostatic response of healthy men to oxygen deprivation.

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Thesis (Ph. D.)--West Virginia University, 2002. / Title from document title page. Document formatted into pages; contains iii, 178 p. Vita. Includes abstract. Includes bibliographical references (p. 170-173).

published_or_final_version / Public Administration / Master / Master of Social Sciences