Verification of system properties of polynomial systems using discrete-time approximations and set-based analysis

Magdeburg, Univ., Fak. für Elektrotechnik und Informationstechnik, Diss., 2015

Two new species of the Drosophila serido sibling set (Diptera, Drosophilidae)

Drosophila antonietae sp. nov. and D. gouveai sp. nov. are members of the D. buzzatii cluster of the D. repleta species group of the genus Drosophila. They can be distinguished from their cryptic species, D. borborema Vilela & Sene, 1977, D. koepferae Fontdevila & Wasserman, 1988, D. serido Vilela & Sene, 1977, and D. seriema Tidon-Sklorz & Sene, 1995 by morphological, genetic and ecological criteria.

Measuring sustained superior performance at the firm level

This paper proposes a two-dimensional Strategic Performance Measure (SPM) to evaluate the achievement of sustained superior performance. This proposal builds primarily on the fact that, under the strategic management perspective, a firm's prevalent objective is the pursuit of sustained superior performance. Three basic conceptual dimensions stem from this objective: relativity, sign dependence, and dynamism. These are the foundations of the SPM, which carries out a separate evaluation of the attained superior performance and of its sustainability over time. In contrast to existing measures of performance, the SPM provides: (i) a dynamic approach by considering the progress or regress in performance over time, and (ii) a cardinal measurement of performance differences and its changes over time. The paper also proposes an axiomatic framework that a measure of strategic performance should comply with to be theoretically and managerially sound. Finally, an empirical illustration of the Spanish banking sector during 1987-1999 is herein provided by discussing some relevant cases.

On the set of subrings wich are directed unions of Artinian subrings

The paper contributes to the investigation of zero-dimensional rings which can be written as a directed union of Artinian subrings. We give conditions on DU(R) in order to be nonempty.

A note on Spatial Autocorrelation at a Local Level

In this paper we analyze the existence of spatial autocorrelation at a local level in Catalonia using variables such as urbanisation economies, population density, human capital and firm entries. From a static approach, our results show that spatial autocorrelation is weak and diminishes as the distance between municipalities increases. From a dynamic approach, however, spatial autocorrelation increased over the period we analysed. These results are important from a policy point of view, since it is essential to know how economic activities are spatially concentrated or disseminated. Key words: spatial autocorrelation, municipalities. JEL classification: R110, R120

Human capital as a factor of growth and employment at the regional level. The case of Spain

We use statistical techniques to quantify the effects of school attainment on individual wages, participation rates and employment probabilities in Spain, and to measure the contribution of education to labour productivity at the regional level. These estimates are then combined with data on private and public expenditure on education and with information on taxes and social benefits to construct measures of the private and social returns to schooling, to explore the effects of public policies on private incentives to invest in human capital, and to analyse the long-term effects of schooling on public finances. The results are used, together with estimates of the returns to alternative assets, to draw some tentative conclusions regarding the adequacy of the aggregate investment patterns observed in the regions of Spain, and to identify changes in the design of national and EU cohesion and growth policies that may help enhance their effectiveness.

A change would do you good . . . An experimental study on how to overcome coordination failure in organizations

Many organizations suffer poor performance because individuals within the organization fail to coordinate on efficient patterns of behavior. Using controlled laboratory experiments, we study how financial incentives can be used to find a way out of such performance traps. Our experiments are set in a corporate environment where subjects' payoffs depend on coordinating at high effort levels; the underlying game being played repeatedly by employees is a weak-link game. In an initial phase, the benefits of coordination are low relative to the cost of increased effort. Play in this initial phase typically converges to an inefficient outcome with employees failing to coordinate at high effort levels. The experimental design then explores the effects of varying the financial incentives to coordinate at a higher effort level. We find that an increase in the benefits of coordination leads to improved coordination, but, surprisingly, large increases have no more impact than small increases. Once subj

Human capital in a global and knowledge-based economy. Part 2. Asssessment at the EU country level.

This report is an extension and partial update of de la Fuente and Ciccone (2002). It constructs estimates of the private and social rates of return on schooling for fourteen EU countries using microeconometric estimates of Mincerian wage equations, the results of cross-country growth regressions and OECD data on educational expenditures, tax rates and social benefits. The results are used to draw some tentative conclusions regarding the optimality of observed investment patterns and educational subsidy levels.

The demand elasticity on tolled motorways

This paper analyses the elasticities of demand in tolled motorways in Spain with respect to the main variables influencing it. The demand equation is estimated using a panel data set where the cross-section observations correspond to the different Spanish tolled motorways sections, and the temporal dimension ranges from the beginning of the eighties until the end of the nineties. The results show a high elasticity with respect to the economic activity level. The average elasticity with respect to petrol price falls around -0.3, while toll elasticities clearly vary across motorway sections. These motorway sections are classified into four groups according to the estimated toll elasticity with values that range from -0.21 for the most inelastic to -0.83 for the most elastic. The main factors that explain such differences are the quality of the alternative road and the length of the section. The long-term effect is about 50 per cent higher than the short term one; however, the period of adjustment is relatively short.

Repeated games played in a network

Delayed perfect monitoring in an infinitely repeated discounted game is modelled by letting the players form a connected and undirected network. Players observe their immediate neighbors' behavior only, but communicate over time the repeated game's history truthfully throughout the network. The Folk Theorem extends to this setup, although for a range of discount factors strictly below 1, the set of sequential equilibria and the corresponding payoff set may be reduced. A general class of games is analyzed without imposing restrictions on the dimensionality of the payoff space. This and the bilateral communication structure allow for limited results under strategic communication only. As a by-product this model produces a network result; namely, the level of cooperation in this setup depends on the network's diameter, and not on its clustering coefficient as in other models.

Testing of stair climbing point-of-choice prompts in Barcelona at an outdoor set of stairs and scalators on the Montjuïc site

Regular stair climbing has well-documented health dividends, such as increased fitness and strength, weight loss and reduced body fat, improved lipid profiles and reduced risk of osteoporosis. The general absence of barriers to participation makes stair climbing an ideal physical activity (PA) for health promotion. Studies in the US and the UK have consistently shown that interventions to increase the accumulation of lifestyle PA by climbing stairs rather than using the escalators are effective. However, there are no previous in Catalonia. This project tested one message for their ability to prompt travelers on the Montjuïc site to choose the stairs rather than the escalator when climbing up the Monjuïc hill. One standard message, " Take the stairs! 7 minutes of stair climbing a day protects your heart" provided a comparison with previous research done in the UK. Translated into Catalan and Spanish, it was presented on a poster positioned at the point of choice between the stairs and the escalator. The study used a quasi-experimental, interrupted time series design. Travelers, during several and specific hours on two days of the week, were coded for stair or escalator use, gender, age, ethnic status, presence of accompanying children or bags by one observer. Overall, the intervention resulted in a 81% increase in stair climbing. In the follow-up period without messages, stair climbing dropped out to baseline levels. This preliminary study showed a significant effect on stair use. However, caution is needed since results are based on a small sample and, only a low percentage of the sample took the stairs at baseline or the intervention phase . Future research on stair use in Catalonia should focus on using bigger samples, different sites (metro stations, airports, shopping centers, etc) , different messages and techniques to promote stair climbing.