Entrepreneurship can be described as the creation of a venture out of nothing, except for an entrepreneur’s idea. No manuals or blueprints for entrepreneurs‘ particular ideas exists. Add to this plenty of adversities along the way. For many, the entrepreneurial journey ends long before their products or services have reached the market. How do entrepreneurs deal with adversities and goal disruptions on the path to venture creation, and what effects does this have on their ventures? This study focuses on the goal disruptions that entrepreneurs experience and builds a model of perceived resistance. The model illustrates how entrepreneurs appraise goal disruptions, choose certain coping strategies, either eventually overcoming the goal disruptions or terminating their venture creation journey. The key issues affecting how novice entrepreneurs cope with goal disruptions are entrepreneurs’ emotions, life life goals, as well as their energetic resources. / <p>Diss. Stockholm : Handelshögskolan, 2008</p>

Aquatic organisms in response to toxic insults from environmental pollutants activate defence systems including the aryl hydrocarbon receptor (AhR) in an attempt to metabolize and excrete these toxicants and their metabolites. These detoxification mechanisms however may come with certain energetic costs. I hypothesize that the activation of the AhR by β-Naphthoflavone (β-NF), a model AhR agonist, results in increased energetic costs requiring metabolic reorganization in rainbow trout hepatocytes. While the results obtained suggest that there are no significant energetic costs of AhR activation, analysis of enzyme activities suggests possible metabolic reorganization. This study also showed significant changes in cellular processes in hepatocytes over the incubation periods which previously were not reported. Furthermore, for the first time in fish hepatocytes, metabolic flux analysis (MFA) was used to examine intra-cellular metabolism, the applicability of which is discussed.

In this thesis we examine the generation mechanisms of Pc 5 ULF waves during geomagnetic storms. Also, we study the interaction between Pc 5 ULF waves and energetic particles in the radiation belts and the observed energetic particle flux modulation by Pc 5 ULF waves is verified using particle simulations. Firstly, we present case studies of Pc 5 pulsations using ground-based magnetometer and satellite data during geomagnetic storm times, specifically we selecting three storm time events which show a brief increase in Dst in the main phase of the storms. By studying these events, we attempt to identify the generation mechanisms responsible for the geomagnetic pulsations. The observed pulsations exhibit the characteristic features of a Field Line Resonance. Our results also show evidence for the penetration of ULF wave power in the Pc 5 band to much lower L-shells than normal, suggesting significant reduction of the local Alfven eigenfrequency continuum as compared to non-storm times. This may have considerable significance for the interaction between ULF waves and MeV electrons in the outer radiation belt during storms. Secondly, based on the hypothesis that Pc 5 ULF waves may play an important role in energetic particle dynamics in the radiation belt and ring current, we investigated the relationship between Pc 5 pulsations and energetic particle flux oscillations. We observed very strong Pc 5 oscillations during the great magnetic storm of March 24, 1991 [Lee et al., 2007] and electron flux simultaneously oscillating with the same frequencies in the time domain. We also characterize two more events and present an examination of the relationship between the electron flux modulation and Pc 5 ULF pulsations. Based on our observations, the modulation of energetic particles might be associated with a drift-resonance interaction, or the advection of an energetic particle density gradient. Finally, we numerically calculate the trajectories and energy change of charged particles under the influence of model ULF wave electric fields. This modeling work is used to help to explain the observations and provides evidence which supports the modulation mechanisms such as advection of a flux gradient and drift resonance.

Energetic structural materials (ESMs) constitute a new class of materials that provide dual functions of strength and energetic characteristics. ESMs are typically composed of micron-scale or nano-scale intermetallic mixtures or mixtures of metals and metal oxides, polymer binders, and structural reinforcements. Voids are included to produce a composite with favorable chemical reaction characteristics. In this thesis, a continuum approach is used to simulate gas-gun or explosive loading experiments where a strong shock is induced in the ESM by an impacting plate. Algorithms are developed to obtain equations of state of mixtures. It is usually assumed that the shock loading increases the energy of the ESM and causes the ESM to reach the transition state. It is also assumed that the activation energy needed to reach the transition state is a function of the temperature of the mixture. In this thesis, it is proposed that the activation energy is a function of temperature and the stress state of the mixture. The incorporation of such an activation energy is selected in this thesis. Then, a multi-scale chemical reaction model for a heterogeneous mixture is introduced. This model incorporates reaction initiation, propagation, and extent of completed reaction in spatially heterogeneous distributions of reactants. A new model is proposed for the pore collapse of mixtures. This model is formulated by modifying the Carol, Holt, and Nesterenko spherically symmetric model to include mixtures and compressibility effects. Uncertainties in the model result from assumptions in formulating the models for continuum relationships and chemical reactions in mixtures that are distributed heterogeneously in space and in numerical integration of the resulting equations. It is important to quantify these uncertainties. In this thesis, such an uncertainty quantification is investigated by systematically identifying the physical processes that occur during shock compression of ESMs which are then used to construct a hierarchical framework for uncertainty quantification.

Temperature is arguably the most important abiotic factor influencing the embryonic development in ectothermic species. Incubation temperature has demonstrated effects on offspring phenotypes in ectotherms, including traits such as sex, size, shape, colouration and post-hatch growth and survival. However, in endotherms the influence temperature has on development is relatively unexplored due to the narrow range of temperatures that embryonic endotherms are exposed to during develop. Megapode birds utilize environmental heat sources to incubate their eggs and therefore provide a potential model to test how temperature influences embryonic development and offspring phenotypes in endotherms. I used the Australian Brush-turkey (Alectura lathami), a megapode bird that incubates its eggs in mounds of soil and leaf litter to investigate the effects of temperature on embryonic development and chick morphology. Previous reports of Australian Brush-turkey incubation mound temperatures relied on spot measurements and theoretical modeling and thus have not provided a comprehensive examination of the range of temperatures Brush-turkey embryos are exposed to and how these might vary during the course of incubation. Therefore to examine the range of temperatures experienced by developing embryos I continuously recorded the temperature of eggs and mound material at naturally occurring positions within incubation mounds over the full developmental period. As in previous studies I found the average incubation temperature to be about 34°C, however egg temperatures typically fluctuated more than previously reported or predicted from modeling. The thermal tolerance of Brush-turkeys is remarkable compared to non-megapode birds, with embryos developing successfully despite prolonged exposure to sub-optimal temperatures over the range 25-40°C. I also demonstrated that the incubation period was negatively correlated with mean incubation temperature. To simplify the examination of temperature effects on embryonic development, constant temperature artificial incubation of Brush-turkey eggs was used to determine influence of incubation temperature on the energetics of embryonic development and the sex ratio, morphology and chemical composition of chicks. Because initial investigation of mound temperatures determined the mean incubation temperature in Brush-turkeys to be 34°C this was used as the preferred temperature for constant temperature incubation with 32°C and 36°C representing low and high temperatures respectively. Previously, the sex ratio of Brush-turkey chicks at hatching was shown to be temperature dependent. A thermally sensitive period early in development resulted in more females hatching from high temperature and more males hatching from low temperatures with an equal ratio at the preferred temperature. Using molecular sexing techniques to determine the sex of both failed embryos and chicks that hatched, I established that at laying the sex ratio of eggs was 50:50, and that temperature-dependent sex-biased embryo mortality was the mechanism behind the skewed sex ratio of chicks hatching from non-preferred temperatures. Low incubation temperature increased female embryonic mortality and high incubation temperature increased male embryonic mortality. This represents a novel mechanism operating to alter sex ratios in a bird species and offers an unparalleled system to explore sex allocation theory. It is well established that temperature influences the rate of development and the morphology of offspring in reptilian species. Also, in a previous study using artificially incubated Brush-turkey eggs, temperature was found to affect the mass of chicks but not their size (linear dimensions). This finding suggests that at different incubation temperatures the amount of yolk converted into tissue during embryonic development is influenced by incubation temperature. I tested this hypothesis by incubating eggs at different constant temperatures and found high incubation temperatures produce chicks with lighter yolk-free bodies and heavier residual yolks but similar linear dimensions compared to chicks hatching from lower temperatures. Because eggs incubated at low temperatures have longer incubation periods, I hypothesized the proportion of lipid in the yolk-free body would be higher in chicks emerging from eggs incubated at low temperature because more time is available for the conversion of yolk to fat bodies during embryonic development. This hypothesis was not supported as the composition of yolk-free chicks (total water, lipid, protein and ash) was not temperature dependent. A previous study in Malleefowl (Leipoa ocellata), another megapode bird, found that the total energetic cost of production was influenced by incubation temperature. Such that embryos developing at low temperatures required 72% more energy than embryos developing at high temperatures. However these findings were contrary to expectation from studies of reptilian incubation where the energetic cost of development is independent of temperature. Therefore I tested the hypothesis that the total energetic cost of development is temperature dependent in the Australian Brush-turkey. I used bomb calorimetry to measure the energy content of freshly laid eggs and of chicks (both the yolk-free body and residual yolk) that had hatched from eggs incubated 32oC, 34oC and 36oC. I found that the total energy content of chicks at hatching was greater in chicks emerging from eggs incubated at 34oC and 36oC compared to eggs incubated at 32oC. My thesis work demonstrated that incubation temperature is more variable for Brush-turkey embryos than for non-megapode birds and that even a small difference in temperature can have important effects on chick sex ratios, morphology and energy reserves. I have shown that incubation under artificial constant temperature conditions can significantly alter the developmental trajectories and phenotypic outcomes for chicks. In addition to laboratory based work, future studies should continue to examine how embryonic development and chick attributes are influenced by temperatures experienced under natural incubation conditions. Furthermore, investigation is required to determine how incubation temperature induced differences in hatchling phenotypes influence the post-hatch grow and fitness of chicks.

Le développement de nouvelles compositions propulsives, pour applications stratégique et spatiale par exemple, conduit à élaborer des charges énergétiques de plus en plus puissantes... / The development of new compositions of propellants, for strategic and space applications for instance, leads to synthesis of more and more powerful energetic materials...

Made available in DSpace on 2014-06-11T19:30:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-07-27Bitstream added on 2014-06-13T18:40:47Z : No. of bitstreams: 1 fedrizi_lfb_dr_jabo.pdf: 4963590 bytes, checksum: 3366228ade45dcb20b67f693544b6653 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / O processamento dos alimentos e rações, tais como extrusão e peletização, cada vez mais fazem parte de qualquer produção de ração animal. Nesse sentido, o conhecimento das alterações químico-bromatológicas no alimento submetido ao processamento é imprescindível para a correta suplementação das exigências nutricionais das espécies animais, além de buscar as melhores condições de processamento na tentativa de minimizar degradações e perdas de biodisponibilidade dos nutrientes de alimentos submetidos a tratamento térmico. O objetivo deste estudo foi caracterizar a composição de nutrientes de alimentos energéticos utilizados na nutrição animal (milho, farelo de trigo, quirera de arroz e sorgo), antes e após serem submetidos ao processamento por peletização ou extrusão. Foram analisados proteína bruta (PB), extrato etéreo (EE), matéria mineral (MM), energia bruta (EB), fibra bruta (FB), fibra em detergente neutro (FDN), açúcares solúveis (AS), amido (AMD), amilose (AML), amilopectina (AMP). A geleificação do amido foi observada por meio de microscopia eletrônica de varredura (MEV). Além disso, foram comparadas a metodologia de Weende, pela equação do extrativo não nitrogenado (ENN) e a de Van Soest, pela equação dos carboidratos não fibrosos (CNF), para fracionamento e determinação dos carboidratos digeríveis. Os resultados demonstraram diferenças na determinação de carboidratos (CHO) por ambas as metodologias, com superestimação de CHO digerível quando se utiliza a metodologia de Weende. A extrusão dos alimentos energéticos provocou diminuição dos teores de PB, EE e FDN no farelo de trigo, com tendência ao mesmo comportamento para os demais alimentos. Não foram observadas diferenças na análise dos alimentos peletizados, quando comparados com os crus. As micrografias de MEV mostraram maiores áreas de geleificação nos... / The processing of animal foods, as extrusion and pelletization, take part in all production of animal foods more and more. Therefore, it is very important to know about the chemical-bromatologic changes in the source which was put in a processing for the correct supplementation of the nutritional needs of the species. Also, it allows to find better conditions of processing in the attempt of decreasing degradations and losses of bioavailability of the nutrients in the foods submitted in a thermal treatment. The objective of this study was to characterize the composition of nutrients in the energetic sources which were used in the animal nutrition (corn, wheat meal, broken rice or sorghum), before and after of being submitted to the processing by pelletization and extrusion. There were analyzed the crude protein (CP), ether extract (EE), mineral matter (MM), crude energy (CE), crude fiber (CF), fiber in neutral detergent (FND), soluble sugars (SS), starch (ST), amylose (AML), amylopectin (AMP). The gelatinization of the starch there were observed by scanning electron microscopy (SEM). Also, the methodology of Weende by equation of the nonnitrogen extract (NNE) and the methodology of Van Soest by equation of the nonfiber carbohydrates (NFC) were compared for fractionation and determination of the digestible carbohydrates. The results showed difference in the determination of carbohydrates (CHO) in both methodologies, with overestimation of the digestible CHO when it is utilized in the methodology of Weende. The extrusion of the energetic sources caused decrease on CP, EE and FND in the wheat meal, with tendency of the same behaviour to the other sources. However, in the analysis of the pelletized sources, no differences were observed, if compared with the crude ones. The micrographs of SEM showed larger areas of gelatinization to extruded sources, especially in the sorghum and broken rice

Autotomy (self-induced loss) of body parts has evolved independently as a predator defense mechanism in several major animal phyla. The mechanism among vertebrates, including 13 of the 20 recognized lizard families, is tail autotomy. Its occurrence among the majority of lizard families offers an excellent opportunity to examine the effects of a major selective force on the ecology and evolution of a group of organisms. The research of this study was designed to examine experimentally (i) the function of tail autotomy, (ii) the function of autotomized tail movement, (iii) the energetics of autotomized tail movement, and (iv) the energetic costs of autotomy of an energy-rich tail to reproduction.

L'étude et la compréhension du comportement des flammes de diffusion sont nécessaires et ceci à cause de leur présence dans diverses applications industrielles. Dans la présente étude, cette flamme de diffusion laminaire est issue d'un jet circulaire de méthane et d'un jet coaxial d'air. Deux moyens sont proposés afin d'influencer cette flamme: l'application d'un champ magnétique non-homogène et l'enrichissement du jet d'air coaxial en oxygène. L'effet de ces deux facteurs est étudié au niveau des caractéristiques de la flamme hauteur de décrochage ou lift et la longueur de la flamme), son comportement, sa stabilité et les instabilités d'écoulement en amont de la flamme, de front de flamme et de sommet de la flamme (flickering). L'effet du champ magnétique dépend du signe de son gradient, et cet effet est dû à la génération d'une force magnétique et de la modification des courants de convection. L'enrichissement de l'air en oxygène a un effet stabilisant sur la flamme, une meilleure efficacité énergétique est remarquée. Le champ magnétique et l'enrichissement en oxygène modifient l'amplitude et la fréquence des instabilités évoquées. Un avantage majeur de ces moyens de contrôle pourrait être une stabilisation de la flamme décrochée a la sortie du brûleur. / Studying and understanding the behavior of diffusion flames becomes of great importance becauseof their presence in different industrial applications. In this study, the laminar diffusion flame isissued from a circular jet of methane and a coaxial jet of air. Two ways are proposed to influencethis flame: the application of a non-homogeneous magnetic field and enrichment of air with oxygen.The effect of these two factors is studied on the flame characteristics (lift-off height and flamelength), its behavior, stability and the instabilities of the upstream flow, the flame base and theflame top (flickering). The effect of the magnetic field depends on the sign of its gradient, and it'sdue to the generation of a magnetic force and the influence on the convection motion. Enrichmentof air with oxygen is having a stabilizing effect on the flame. Magnetic field and oxygen enrichmentcan modify the amplitude and the frequency of different kind of instabilities. The major advantageconsists in the stabilization of the flame on the burner rim.

Objetivos: Medir o gasto e estimar a ingestão energética de adolescentes asmáticos com excesso de peso e comparar com asmáticos eutróficos e não asmáticos com excesso de peso. Metodologia: Estudo transversal incluindo 69 adolescentes de 10 a 18 anos. Foram comparados três grupos que foram pareados. Para avaliação nutricional utilizaram-se medidas antropométricas e de composição corporal. O gasto energético foi medido por calorimetria indireta e a ingestão energética estimada por inquéritos alimentares. Resultados: Cada grupo era composto por 23 adolescentes, sendo 13 do sexo masculino, com média de idade 12,39±2,40 anos. Os resultados a seguir são apresentados, respectivamente, para os grupos: asmáticos com excesso de peso; asmáticos eutróficos e não asmáticos com excesso de peso: índice de massa corporal (24,83 ± 2,73Kg/m2), (19,01 ± 2,10 Kg/m2) e (25,35 ± 3,66Kg/m2); gasto energético de repouso (GER) (1550,24±547,23Kcal/dia), (1540,82±544,22Kcal/dia) e (1697,24 ± 379,84Kcal/dia); estimativa da ingestão energética (2068,75± 516,66Kcal/dia), (2174,05± 500,55Kcal/dia) e (1673,17 ± 530,68Kcal/dia). O GER não foi estatisticamente diferente entre os grupos, mesmo quando ajustado pela massa magra e massa gorda (f=0,186; p=0,831). Somente nos grupos dos adolescentes asmáticos, a estimativa da ingestão energética foi maior que o GER. Conclusão: O GER foi semelhante entre os grupos. A estimativa da ingestão energética dos adolescentes asmáticos foi maior que o GER. / Objectives: To measure resting energy expenditure and calculate caloric intake of asthmatic adolescents with excess body weight and compare results with those of groups of adolescents eutrophic asthmatics and no-asthmatic adolescents with excess body weight. Methods: Cross-sectional study with 69 adolescents aged 10 to 18 years divided into three matched groups. Nutritional status was assessed using anthropometric and body composition measurements. Indirect calorimetry was used to measure energy expenditure; caloric intake was estimated from dietary recalls. Results: In each group, there were 23 adolescents (10 girls) aged 12.39±2.40 years. Results for each group (asthmatic adolescents with excess body weight; adolescents eutrophic asthmatics; and no-asthmatic adolescents with excess body weight) were, respectively: Body mass index = 24.83±2.73 kg/m2, 19.01±2.10 kg/m2, and 25.35±3.66 kg/m2; resting energy expenditure (REE) = 1550.24±547.23 kcal/day, 1540.82±544.22 kcal/day, and 1697.24±379.84 kcal/day; estimated caloric intake = 2068.75±516.66 kcal/day, 2174.05±500.55 kcal/day, and 1673.17±530.68 kcal/day. REE between groups was not statistically different, not even after correction for lean mass and fat mass (F=0.186; P=0.831). Estimated caloric intake was greater than REE only in the group of adolescents with asthma. Conclusion: REE was not significantly different between groups. Estimated caloric intake was greater than REE in the group of adolescents with asthma.