The effect of competition on manager's compensation : evidence from a quasi-natural experiment

This paper studies the effect of competition on executive compensation. We estimate the effect of increased product market competition on the performance-pay sensitivity of CEOs, and contrast it with the effect for department managers and other workers in the corporation. We use a recent reform that simplied firm entry regulation in Portugal as a quasi-natural experiment. The empirical strategy exploits the staggered implementation of the reform across municipalities. Using linked employer-employee data for the universe of workers and firms, we show that increased product market competition, following the deregulation, decreased the sensitivity of pay to performance of CEOs and other managers, with no significant effects found for other workers. These findings are consistent with existing theoretical results in a principal-agent framework that a fall in entry costs leads to weaker managerial incentives.Fundação para a Ciência e a Tecnologia through the Applied Microeconomics Research Unit, award no. PEst-OE/EGE/UI3181/2014. Portuguese Ministry of Labor and Social Solidarity and the O¢ce for National Statistics (INE

Substrate-Dependent Activation of Polyphenol Oxidase in Red Clover

Polyphenol oxidases (PPO) are copper metaloproteins that catalyse the oxidation of o-diphenols to quinones, highly reactive molecules which readily bind to nucleophilic sites on cellular components and proteins. Red clover protein, due to this enzyme is resistant to protease degradation during. Theses enzymes (circa. 60-65 kDa) are located in the thylakoid lumen and can be converted to a 40-45 kDa form by proteolysis both in vitro and in vivo (Gelder et al., 1997). Conversion to the smaller form has been demonstrated to confer activity at neutral pH. Other treatments, such as the presence of lipids or detergents eg. SDS, can also confer activity at pH7 (Gelder et al., 1997). Here we describe studies on treatments that affect red clover PPO activity at neutral pH, which is equivalent to the physiological pH of macerated/homogenised leaf extracts

What cell wall components are the best indicators for Miscanthus digestibility and conversion to ethanol following variable pretreatments?

Background: Energy crops including Miscanthus provide a storable, portable energy source which can be used to complement a wide range of products and energy generation systems. Miscanthus is predominantly used in Europe as a combustion material for electricity generation but also has the potential for biochemical conversion due to its high yield and low-nutrient requirements. The ratio of holocellulose (hemicellulose and cellulose combined) to acid detergent lignin (H:L) within the senesced material has previously been shown to indicate the relative suitability of Miscanthus accessions for thermochemical conversion. In this study, the ratio was assessed to examine its use as a selection aid for biochemical conversion. 20 highly-characterised Miscanthus accessions were saccharified using an enzyme mix to determine optimum sugar release. Nine of these accessions spanning high, medium and low H:L ratios were then autoclaved with dilute acid, alkali or water, and enzymically hydrolysed and fermented to produce ethanol. Samples taken throughout the process allowed assessments of released sugars. Results: Enzymic degradation of the biomass showed a relationship between H:L ratio and glucose release, with high glucose release for high H:L ratio accessions and vice versa. Xylose release showed no such relationship. This relationship was maintained following pretreatments and enzyme saccharification, where compound analysis showed that following all pretreatments, accessions with high H:L ratios repeatedly had the highest releases of glucose, xylose and arabinose, and produced more ethanol. Release of all measured compounds increased with the pretreatment severity and ethanol yields from each pretreatment correlated with the respective glucose yield, providing assurance that any inhibitory compounds generated were tolerated by the fermentation yeast. Strong correlations were also seen between glucose release, ethanol and cell wall components, with cellulose showing the highest correlations with ethanol yields for some treatments and H:L ratio with others. Conclusions: The H:L ratio is a good predictor of ethanol yields and sugar release from Miscanthus in this study but individual components lignin and cellulose also correlate well, especially for hot water and mild acid pretreatments. In conclusion, use of the H:L ratio does not provide any advantages over the concentration of individual cell wall components for predicting sugar release and ethanol yields.publishersversionPeer reviewe

Polyphenol oxidase affects normal nodule development in red clover (Trifolium pratense L.)

Polyphenol oxidase (PPO) may have multiple functions in tissues depending on its cellular or tissue localisation. Here we use PPO RNAi transformants of red clover (Trifolium pratense) to determine the role PPO plays in normal development of plants, and especially in N2-fixing nodules. In red clover, PPO was not essential for either growth or nodule production, or for nodule function in plants grown under optimal, N-free conditions. However, absence of PPO resulted in a more reduced environment in all tissues, as measured by redox potential, and caused subtle developmental changes in nodules. Leaves and, to a lesser extent nodules, lacking PPO tended to accumulate phenolic compounds.A comparison of nodules of two contrasting clones by microscopy revealed that nodules lacking PPO were morphologically and anatomically subtly altered, and that phenolics accumulated in different cells and tissues. Developing nodules lacking PPO were longer, and there were more cell layers within the squashed cell layer (SCL), but the walls of these cells were less thickened and the cells were less squashed. Within the N2-fixing zone, bacteroids appeared more granular and were less tightly packed together

A construção da santidade em Inácio de Loyola

Orientadora : Profª. Drª. Ana Paula Vosne MartinsMonografia (graduação) - Universidade Federal do Paraná, Setor de Ciências Humanas, Letras e Artes, Curso de Graduação em HistóriaInclui referência

Pivot-and-bond model explains microtubule bundle formation

During mitosis, microtubules form a spindle, which is responsible for proper segregation of the genetic material. A common structural element in a mitotic spindle is a parallel bundle, consisting of two or more microtubules growing from the same origin and held together by cross-linking proteins. An interesting question is what are the physical principles underlying the formation and stability of such microtubule bundles. Here we show, by introducing the pivot-and-bond model, that random angular movement of microtubules around the spindle pole and forces exerted by cross-linking proteins can explain the formation of microtubule bundles as observed in our experiments. The model predicts that stable parallel bundles can form in the presence of either passive crosslinkers or plus-end directed motors, but not minus-end directed motors. In the cases where bundles form, the time needed for their formation depends mainly on the concentration of cross-linking proteins and the angular diffusion of the microtubule. In conclusion, the angular motion drives the alignment of microtubules, which in turn allows the cross-linking proteins to connect the microtubules into a stable bundle

Desirable plant cell wall traits for higher-quality miscanthus lignocellulosic biomass

Additional file 7. Box and whisker plots showing the distribution of biomass compositional measurements, and the P-values of t tests used to discriminate between genotypes with high or low saccharification efficiency indices