On the upper bound of the number of limit cycles obtained by the second order averaging method I

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On the upper bound of the number of limit cycles obtained by the second order averaging method II

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On the number of K3,3-minor-free and maximal K3,3-minor-free graphs

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Regulation in the Age of Globalization: The Difussion of Regulatory Agencies across Europe and Latin America

One of the most notable characteristics of the change in governance of the past two decades has been the restructuring of the state, most notably the delegation of authority from politicians and ministries to technocrats and regulatory agencies. Our unique dataset on the extent of these reforms in seven sectors in 36 countries reveals the widespread diffusion of these reforms in recent decades. In 1986 there were only 23 agencies across these sectors and countries (less than one agency per country); by 2002 this number had increased more than seven-fold, to 169. On average these 36 countries each have more than four agencies in the seven sectors studied. Yet the widespread diffusion of these reforms is characterized by cross-regional and cross-sectoral variations. Our data reveal two major variations: first, reforms are more widespread in economic regulation that in social spheres; second, regulatory agencies in the social spheres are more widespread in Europe than in Latin America. Why these variations in the spread of the reforms? In this paper we present for the first time the regulatory gaps across regions and sectors and then move on to offer some explanations for these gaps in a way that sheds some light on the nature of these reforms and on their limits. Our explanatory framework combines diffusion and structural explanations and in doing so sheds new light on the global diffusion of public policy ideas.

Car ownership and access to jobs in Spain

This study analyses the impact that job accessibility in public transport has on car ownership. An ordered probit explaining the number of cars per household is estimated as a function of head of household characteristics, household characteristics and job accessibility. The data used in the analysis come from the Microcensus of year 2001 of the Spanish Institute of Statistics for the areas of Barcelona and Madrid. Our results show a significant effect of accessibility on car ownership. Additionally, we carried out simulation exercises in which the expected number of vehicles decreases as accessibility improves. For instance, in the case of households living outside the central city, an improvement of accessibility up to the average level of the central city would offset the effect of the number of working adults on the expected number of vehicles.

Experimental investigation of transient natural convection cooling of high prandtl number fluid with variable viscosity

Report for the scientific sojourn at the James Cook University, Australia, between June to December 2007. Free convection in enclosed spaces is found widely in natural and industrial systems. It is a topic of primary interest because in many systems it provides the largest resistance to the heat transfer in comparison with other heat transfer modes. In such systems the convection is driven by a density gradient within the fluid, which, usually, is produced by a temperature difference between the fluid and surrounding walls. In the oil industry, the oil, which has High Prandtl, usually is stored and transported in large tanks at temperatures high enough to keep its viscosity and, thus the pumping requirements, to a reasonable level. A temperature difference between the fluid and the walls of the container may give rise to the unsteady buoyancy force and hence the unsteady natural convection. In the initial period of cooling the natural convection regime dominates over the conduction contribution. As the oil cools down it typically becomes more viscous and this increase of viscosity inhibits the convection. At this point the oil viscosity becomes very large and unloading of the tank becomes very difficult. For this reason it is of primary interest to be able to predict the cooling rate of the oil. The general objective of this work is to develop and validate a simulation tool able to predict the cooling rates of high Prandtl fluid considering the variable viscosity effects.

Computation of an integral basis of a quartic number field

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Establiment de bases científiques per al desenvolupament d'una estratègia integrada per avaluar toxicitat en reproducció

Report for the scientific sojourn at the National Institute for Public Health and the Environment (RIVM), Netherlands, from 2006 to 2008. This project aimed at creating scientific elements that could help deriving an integrated testing strategy for reproductive toxicity. Part of the project focused on the use of alternative tests for regulatory purposes. An in vitro-in vivo extrapolation method for embryotoxicity was proposed and evaluated. In vitro and in vivo dose descriptors were correlated; however, the scatter in the correlation was too large to allow an accurate estimation of an in vivo dose from an in vitro dose. The in vitro-in vivo extrapolation method together with toxicokinetic data was also applied to a category of substances (phthalates). Although based on a limited number of substances, the results suggested that in vitro-in vivo extrapolation for embryotoxicity is possible within a category of compounds if adequate toxicokinetic data is available. Because of the limitations that still remain in the use of alternative tests for reproductive toxicicity, other approaches to reduce animal testing were explored. Thus, a database of reproductive toxicity studies was created to retrospectively evaluate the comparative value of some studies or elements in a particular study. When compared to the subchronic toxicity study, the rat two-generation reproductive toxicity study had a considerable impact on the identification of hazard for reproductive toxicity, but not on the overall NOAEL. Among the two-generation studies included in our database, the second generation affected neither the overall NOAEL nor the critical effect. The rat and the rabbit developmental toxicity studies were, on average, similarly sensitive. However, for certain substances the developmental study in either one of the two species appeared to be more sensitive than in the other species.

Computation of an integral basis of quartic number field

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Conjugacy of piecewise linear Lorenz map that expand on average

For piecewise linear Lorenz map that expand on average, we show that it admits a dichotomy: it is either periodic renormalizable or prime. As a result, such a map is conjugate to a ß-transformation.

Health care utilization among immigrants and native-born populations in 11 European countries. Results from the Survey of Health, Ageing and Retirement in Europe

Objective: This study examines health care utilization of immigrants relative to the native-born populations aged 50 years and older in eleven European countries. Methods. We analyzed data from the Survey of Health Aging and Retirement in Europe (SHARE) from 2004 for a sample of 27,444 individuals in 11 European countries. Negative Binomial regression was conducted to examine the difference in number of doctor visits, visits to General Practitioners (GPs), and hospital stays between immigrants and the native-born individuals. Results: We find evidence those immigrants above age 50 use health services on average more than the native-born populations with the same characteristics. Our models show immigrants have between 6% and 27% more expected visits to the doctor, GP or hospital stays when compared to native-born populations in a number of European countries. Discussion: Elderly immigrant populations might be using health services more intensively due to cultural reasons.

On the number of higher order Delaunay triangulations

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A functional equation related to the product in a quadratic number field

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Determinants of high-growth firms:why do some countries have more high-growth firms than others?

High-growth firms have been shown to be a key factor for economic growth and structural change. This paper analyses the determinants of the number of high-growth firms in a country for 17 OECD countries between 1999 and 2005, using the Amadeus data set, the GEM data set, and others. The first contribution of this paper is that it is – as far as we know – the first empirical analysis of high-growth firms at the country level on the basis of actual measured growth. Second, we find indicative empirical evidence for three driving forces of high growth, viz. entrepreneurship, institutional settings, and opportunities for growth, all in accordance with theory and empirical findings in related fields of research. Third, the paper gives a tentative explanation of the differences in the average percentage of high-growth firms between countries. Finally, the paper gives some clues for policy makers how to promote high-growth firms. Keywords: high-growth firms, fast growing firms, entrepreneurship, institutional obstacles, opportunities for growth