Lyapunov exponents in Hilbert geometry

We study the behaviour of a Hilbert geometry when going to infinity along a geodesic line. We prove that all the information is contained in the shape of the boundary at the endpoint of this geodesic line and have to introduce a regularity property of convex functions to make this link precise. The point of view is a dynamical one and the main interest of this article is in Lyapunov exponents of the geodesic flow.Comment: 34 pages, comments are welcom

Zermelo deformation of Finsler metrics by Killing vector fields

We show how geodesics, Jacobi vector fields and flag curvature of a Finsler metric behave under Zermelo deformation with respect to a Killing vector field. We also show that Zermelo deformation with respect to a Killing vector field of a locally symmetric Finsler metric is also locally symmetric

Lower and upper bounds for the Lyapunov exponents of twisting dynamics: a relationship between the exponents and the angle of the Oseledet's splitting

We consider locally minimizing measures for the conservative twist maps of the $d$-dimensional annulus or for the Tonelli Hamiltonian flows defined on a cotangent bundle $T^*M$. For weakly hyperbolic such measures (i.e. measures with no zero Lyapunov exponents), we prove that the mean distance/angle between the stable and the unstable Oseledet's bundles gives an upper bound of the sum of the positive Lyapunov exponents and a lower bound of the smallest positive Lyapunov exponent. Some more precise results are proved too

Incentives for pollution control - regulation and public disclosure

An increasing number of regulators have adopted public disclosure programs to create incentives for pollution control. Previous empirical analyses of monitoring and enforcement issues have focused strictly on the impact of such traditional practices as monitoring (inspections) and enforcement (fines and penalties) on polluters'environmental performance. Other analyses have separately focused on the impact of public disclosure programs. But can these programs create incentives in addition to the normal incentives of fines and penalties? The authors study the impact of both traditional enforcement and information strategies in the context of a single program, to gain insights into the relative impact of traditional (fines and penalties) and emerging (public disclosure) enforcement strategies. Their results suggest that the public disclosure strategy adopted by the province of British Columbia, Canada, has a greater impact on both emission levels and compliance status than do orders, fines, and penalties traditionally imposed by the courts and the Ministry of the Environment. But their results also demonstrate that adopting stricter standards and higher penalties also significantly affected emission levels. Policymakers, take note: 1) The presence of strong, clear standards together with a significant, credible penalty system sends appropriate signals to the regulated community, which responds by lowering pollution emissions. 2) The public disclosure of environmental performance creates strong additional incentives to control pollution.Public Health Promotion,Water and Industry,Water Conservation,Environmental Economics&Policies,Health Monitoring&Evaluation,Environmental Economics&Policies,Water and Industry,Health Monitoring&Evaluation,Sanitation and Sewerage,TF030632-DANISH CTF - FY05 (DAC PART COUNTRIES GNP PER CAPITA BELOW USD 2,500/AL

Incentives for Pollution Control: Regulation or (and?) Information

An increasing number of regulators have adopted public disclosure programs to create incentives for pollution control. In this paper, we study the impact of British Columbia's list of polluters whereby the province's environmental regulator reveals the name of plants which are either not complying with the regulation or are of concern to the regulator. Simultaneously however, the regulator continues to undertake legal action for those violating the regulation. Previous analyses have focused on studying either the impact of the traditional monitoring and enforcement practices or the impact of information programs. In this paper, we perform an empirical analysis of the impact of both traditional enforcement and information strategies within the context of a single program. We thus provide insights on the relative impact of the traditional (fines and penalties) and emerging (information) enforcement strategies. Our results suggest that British Columbia's list of polluters has a larger impact on both emissions levels and compliance status than orders, fines and penalties traditionally imposed by the Ministry and courts. Our results also demonstrate that the adoption of stricter standards and penalties had a significant impact on emissions levels. De plus en plus de décideurs publics dans le domaine de l'environnement ont adopté des politiques de diffusion de l'information pour créer des incitations à une meilleure performance environnementale. Dans cette étude, nous examinons l'impact d'une liste noire de pollueurs publiée à tous les six mois, depuis 1990, par le Ministère de l'environnement en Colombie-Britannique qui, parallèlement à cela, poursuit une stratégie traditionnelle de contrôle et de mise en application de la réglementation. Les recherches précédentes ont examiné de façon isolée l'impact des mesures traditionnelles de réglementation et l'impact des programmes d'information, alors que nous proposons d'étudier simultanément les effets de ces deux types de mesures. Ce faisant, nous pourrons avoir une idée de l'impact relatif des mesures traditionnelles et émergentes. Nos résultats suggèrent que la liste des pollueurs de Colombie-Britannique a eu un impact plus important que les poursuites et les amendes traditionnellement émises par les autorités gouvernementales. Nos résultats montrent également que l'adoption de normes environnementales plus strictes a eu un effet important sur la performance environnementale des usines étudiées.Regulation, information, Information, réglementation

Challenge of Culture in Africa: From Restoration to Integration

This book was first published as a two-part essay in 1965 and 1967 in ABBIA - Cameroon Cultural Review - under the title 'Idea of Culture'. Its main argument is that indigenous Africans cultures must be the foundation on which the modern African cultural structure should be raised; the soil into which the new seed should be sown; the stem into which the new scion should be grafted; the sap that should enliven the entire organism. This culture, the object of imperialist mockery and rejected, needs rehabilitation. However, such rehabilitation of African culture cannot be a mere archaeological enterprise. It will not answer to dig up the past and live it as it was. Not only is African culture not without its imperfections, times change and African culture must adapt itself, at every turn, to the changing times. In restoring African culture, it is imperative to steer clear of two extremes: on the one hand, the imperialist arrogance which declared everything African as only fit for the scrap-heap and the dust-bin, and, on the other hand, the overly enthusiastic and rather naive tendency to laud every aspect of African culture as if it were the quintessence of human achievement