Two peaks of eclosion dates, about 15 days apart, occur in the same batch of fertilized eggs in the marine midge, Pontomyia oceana. Two hypotheses, the variable adaptive peaks and the bet-hedging hypotheses, were proposed as the ultimate factor of the polymorphic phenomenon. They were tested by experiments controlling feeding amount and photoperiod, as well as selective breeding experiments. The offspring eclosing in the two peaks do not differ in fecundities, egg diameters, thorax and head lengths of males; this is not compatible with the variable adaptive peaks hypothesis. Both peaks exist under various feeding and photoperiods, although peak ratios differed in the former. The results in the first peak lineage did not support there is genetic component in peak ratio determination. The experiments in the second peak lineage had much lower success rates, although the results seemed to suggest a genetic component. The results in a more extreme selection experiment did not support that there is genetic component either. The present results are more compatible with the bet-hedging hypothesis. Wind velocity may be a factor hard to predict by the midges, and it may cause reproductive failure of them. Whereas high emergence synchronization, a prominent feature of the marine midge, may have advantages in many aspects, it also concentrates the risk of total reproductive failure. Spreading offspring to more than one suitable eclosion peak, the midge may have sacrificed short-term reproductive rate for long-term fitness.

Tübingen, Univ., Diss., 2006.

Problem – Lean is a concept used by organizations to become more efficient, thus more competitive. However, it has been documented that only a small portion of all implementations actually succeeds. Research has suggested critical success factors and pointed out top management commitment as being vital for a successful implementation. It is therefore confirmed that without top managers’ involvement, the venture cannot succeed. However, despite existing research on how to succeed, top managers are still lacking commitment which has caused many implementations to fail. Purpose – This study aims to use the side-bet theory of Becker (1960) to explore the phenomena to why top managers’ commitment is vacillating during the implementation of Lean. The research question is; Why is top managers’ commitment not consistent to Lean implementation when regarding their side-bets? Methodology – Data collecting has been qualitative where semi structured interviews have been executed with five top managers of different organizations. Some have succeeded to implement Lean and some have not. The side-bet theory has been used to create a framework for where the empirical data is constrained to. Conclusions – Before and during the implementation, top managers are only committed to a successful implementation if they find themselves having enough penalties associated with a failed implementation. Only when they realize that there exists side-bets and penalties of enough magnitude, their commitment will be consistent and the implementation successful. The side-bets which have shown to be decisive to determine a consistent or deviating commitment are the ones belonging to ‘Generalized cultural expectations’ and ‘Impersonal bureaucratic arrangements’. The penalties associated with these side-bets have been of socially form than economically. Furthermore, these side-bets and penalties have shown to arise when top managers and their organization have made it clear that the Lean venture is of highest priority and any sidestep from it is considered as wrong. Implications – This study has contributed with an understanding of why top manager’s commitment is consistent or deviating during the Lean implementation. Research so far has suggested how top managers’ commitment is deviating and consistent. This study provides the explanation of why. By exploring the answer to why top managers lack commitment, the possibility of ensuring consistent commitment is raised. Referring to Becker (1960) people operates only when they understand why and find value in a certain kind of activity.  Delimitations – The study is only focused on the dimension of continuance commitment. There is a possibility to study other dimensions of commitment in this field of research (i.e. affective and normative commitment).  The findings are based on Swedish top managers, thus using the findings outside Sweden should be proceeded with caution since culture has effect on commitment.

Made available in DSpace on 2014-08-20T13:42:05Z (GMT). No. of bitstreams: 1 Tese_Miguel_Pinto_de_Oliveira.pdf: 962671 bytes, checksum: 4149d63d44ce0a91f63fbaa9e92fe734 (MD5) Previous issue date: 2008-08-01 / Carvões ativados são muito utilizados no tratamento de águas, no processo de refino de açúcar, na clarificação de efluentes, na purificação de ar, etc. Seu poder adsortivo está associado às características texturais como área superficial, volume e área de microporos. Neste trabalho elaborou-se carvão ativado a partir de caroços de pêssego, que atualmente são descartados no meio ambiente. Avaliou-se o rendimento, densidade, índice de fenol, número de iodo e propriedades texturais em função da temperatura de carbonização dos carvões ativados. Observou-se que a 700°C, na concentração do agente ativador ZnCl2 de 6 mol L-1, e tempo de impregnação de 3 horas, obteve-se um índice de iodo médio de 988 mg de I2 g-1, valor superior aos carvões ativados comercializados no Brasil. Portanto, conclui-se que os caroços de pêssegos podem ser utilizados como precursores para a produção de carvão ativado. / Carvões ativados são muito utilizados no tratamento de águas, no processo de refino de açúcar, na clarificação de efluentes, na purificação de ar, etc. Seu poder adsortivo está associado às características texturais como área superficial, volume e área de microporos. Neste trabalho elaborou-se carvão ativado a partir de caroços de pêssego, que atualmente são descartados no meio ambiente. Avaliou-se o rendimento, densidade, índice de fenol, número de iodo e propriedades texturais em função da temperatura de carbonização dos carvões ativados. Observou-se que a 700°C, na concentração do agente ativador ZnCl2 de 6 mol L-1, e tempo de impregnação de 3 horas, obteve-se um índice de iodo médio de 988 mg de I2 g-1, valor superior aos carvões ativados comercializados no Brasil. Portanto, conclui-se que os caroços de pêssegos podem ser utilizados como precursores para a produção de carvão ativado.

L’emploi d’adjuvants fluidifiants est courant pour tout béton. Ceci permet d’améliorer les propriétés rhéologiques à l’état frais: la fluidité initiale et son maintien pendant les 2-3 premières heures de la vie d’un béton. La compréhension de ce mécanisme d’action est encore partielle pour les PCP (copolymères greffés). Ici, le but a été de tester l’hypothèse selon laquelle l’évolution de la quantité de PCP adsorbé par unité de surface minérale instantanée explique quantitativement l’évolution temporelle de la fluidité au cours de la période d’ouvrabilité.Sur un système inerte (calcite), nous avons confirmé que la fluidité est bien gouvernée par l’adsorption: à même adsorption surfacique, la fluidité de la pâte est quasiment identique quelle que soit la structure du PCP. Par ailleurs sur un système inerte (calcite ou ettringite), la modification de la fonction ionique du PCP fournit une solution pour améliorer la résistance de l’adsorption à la variation de la concentration en sulfates.Deux techniques ont été utilisées pour mesurer l’aire interfaciale au cours de l’hydratation d’un système réactif modèle (aluminate tricalcique, gypse, hémihydrate et calcite): l’adsorption de N2 et la relaxométrie du proton de l’eau. L’adsorption du PCP par unité de surface réelle a été calculée et corrélée à la fluidité de la pâte. La relation simple fluidité/adsorption n’est plus vérifiée ici. La présence de PCP a un impact sur l’hydratation du système et l’augmentation de l’étendue de la surface minérale associée. Les PCP vont augmenter la surface spécifique de l’ettringite qui précipite en modifiant sa morphologie. Cet effet est plus marqué quand la densité de greffage du PCP diminue. / Nowadays the use of superplasticizers admixtures becomes unavoidable for concrete. It allows enhancing the rheological properties at the fresh state: the initial flow and slump retention during the 2-3 first hours of the life of a concrete. The understanding of this mechanism is still partly elucidated for PCE (grafted copolymers). The aim of this thesis was to challenge the assumption of the evolution of the adsorbed amount of PCE per instantaneous mineral surface unit as origin of the fluidity temporal evolution during the workability period.On an inert system (calcite), we confirmed that the fluidity is mainly governed by the adsorption level. Thus for a same surface adsorption density, the fluidity of the paste is roughly similar whatever the structure of the PCE. On an inert system also (calcite or ettringite), the modification of the anionic function provides a technological way to improve the resistance of the adsorption against the variation of the sulfate ions concentration.The surface area of a reactive model system (tricalcium aluminate, gypsum, hemihydrate and calcite) has been measured by two techniques during the workability period: the N2 adsorption (BET) and the water proton relaxometry (RMN). The PCE adsorption per surface unit has been calculated and analysed in link with the fluidity of the paste. In that case, the simple relation, shown on the inert system, is not verified because the presence of PCE has also an impact on the hydration and on the extent of the surface area. Especially PCE lead to increase the surface by changing the morphology of ettringite. The specific surface area of ettringite increases when the grafting density of PCE decreases.

The multidisciplinary field of microfluidics has shown great promise for research at the interface of biology, chemistry, engineering, and physics. Laminar flow, versatile fabrication, and small length scales have made microfluidics especially well-suited for single-cell characterization. In particular, the evaluation of single-cell growth rates is of fundamental interest for studying the cell cycle and the effects of environmental factors, such as drugs, on cellular growth. This work presents aspects in the development of a microfluidic cell impedance sensor for measuring the volumetric growth rate of single cells and covers its application in the investigation of a new discovery relating to multidrug resistance in S. cerevisiae. While there are many avenues for the utilization and interpretation of growth rates, this application focused on the quantitative assessment of biological fitness—an important parameter in population genetics and mathematical biology. Through a combination of growth measurements and optics, this work concludes a novel case of bet-hedging in yeast, as well as the first ever case of bet-hedging in eukaryotic multidrug resistance.

Unlike traditional stock exchanges, where bonds, shares and financial derivatives are traded, on the betting exchanges there are traded probabilistic estimates of the results of sporting or social events. The market price of bets, namely the market implied probability is influenced by estimate of the outcome. The specificity of betting exchanges is also a short period to maturity of contracts, and the possibility to trade with the estimated result of one real world event in several sub-markets simultaneously. In theoretical analysis, we have defined the bet, the underlying asset, and the binary betting contract, which is traded on betting exchanges. We have described some practical aspects of trading. Properties of the probabilistic contracts are demonstrated on several examples. Finally, we constructed the mathematical model of a tennis match, which is based on a binomial valuation model. This allows us to compare the market price of a contract with the price recommended by the model.

The diploma thesis is concerned with analysis of behavior of bettors on horse races. The aim is to test the hypothesis that bettors prefer skewness and they are risk averse. In the thesis is used the method of empirical data collection of horse racing in the Czech Republic and their subsequent testing using a regression model. The testing of the presented model did not confirm the hypothesis of skewness preference in the case of betting on horse races in the Czech Republic.

<p>In eukaryotic systems, the genetic material of the cell –DNA– is packed into a protein-dense structure called chromatin. Chromatin structure is critical for preservation of the genetic material as well as coordination of vital processes such as DNA replication, transcription and DNA damage repair. The fundamental repeating unit of chromatin is nucleosome which is composed of an octamer of small alkaline proteins called histones and the DNA wrapped around this octamer. The nucleosomes are then packed into higher-order structures leading to formation of 3D chromatin architecture. The chromatin is a dynamic structure; the spacing between nucleosomes, or the folding of the larger chromatin segments is subjected to alterations during embryonic development, tissue specifications or <i>simply during any event that require gene expression changes</i>. Failure in proper regulation of chromatin structure has been associated with embryonic defects and disease such as cancer. </p> <p>This work has focused on a class of ATP-dependent chromatin remodeling complexes known as switch/sucrose-non-fermentable (SWI/SNF) or BRG-associated factors (BAF) complex. This family of complexes act on chromatin and alter its physical structure by mobilizing histones or nucleosome particles through the activity of its ATPase –BRG1 or BRM, enabling more accessible DNA for the other factors such as transcription factors to localize and recruit transcription machinery. In particular, we discovered and biochemically defined a novel version of this family of chromatin complexes that we named as GLTSCR1/1L-BAF (GBAF). GLTSCR1 and GLTSCR1L are two uncharacterized paralogous proteins that have been identified as BRG1-interacting proteins. Biochemically surveying the essence of this interaction, we realized that these proteins incorporates into a previously unknown SWI/SNF family complex that lacks well-characterized SWI/SNF subunits such as ARID1/2, BAF170, BAF47; instead, uniquely comprise GLTSCR1/1L and bromodomain-containing protein BRD9. Focusing on the GLTSCR1 subunit, we observed that its absence is well-tolerated by many different cell types except slight growth retardation by prostate cancer cells. Expanding the cohort of prostate cancer cells, we realized that not the paralogous subunits GLTSCR1 or GLTSCR1L but unique and non-redundant subunit BRD9 is the major GBAF-dependence in prostate cancer cells. We observed that especially the androgen-receptor positive cell lines have severe growth defects upon <i>BRD9 </i>knockdown or inhibition. <i>In vivo, </i>we showed that xenografts with <i>BRD9 </i>knockdown prostate cancer cells (LNCaP) have smaller tumor size. We demonstrated that BRD9 inhibition can block the expression of androgen-receptor targets. Similarly, <i>BRD9 </i>knockdown and treatment with antiandrogen drug (enzalutamide) has overlapping transcriptional effects. Mechanistically, we showed that BRD9 interacts with AR and it colocalizes with AR in subset of AR -binding sites. Surprisingly, we realized that BRD9 depletion has similar transcriptional and phenotypic effects as BET protein inhibitors. BET protein family contains 4 bromodomain containing proteins (BRD2, BRD3, BRD4, BRDT). These proteins were previously shown to be critical for AR-dependent gene expression. We detected interaction between BRD9 and BRD2/4. We demonstrated that BRD4 and BRD9 had shared binding sites on genome, a fraction of which are co-bound by AR. At particular target sites we showed that BRD9 localization is dependent on BET proteins, but not the other way around. Taking together, we provided some evidences that GBAF targeting through BRD9 can be a novel therapeutic approach for prostate cancer. Growing body of reports suggested that current therapy options targeting the androgen receptor is failing due to acquired resistance. Therefore, targeting the AR pathways via its coregulators such as BET proteins or SWI/SNF complexes can serve as potent alternative approaches. Further research is needed to elucidate the roles of GBAF and BET proteins in androgen receptor independent prostate cancer cells, which are still responsive to GBAF or BET manipulations although to a lesser extent.</p>

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