Performance of the ambient tax: does the nature of the damage matter?

The ambient tax is often considered as an effcient instrument to achieve a …rst best outcome of ambient pollution when the regulator is less informed than the polluters. Since the ambient tax was never imple- mented in the …eld, empirical evidence is missing. Available experimental …ndings provide mixed evidence: effciency is higher under external dam- age, i.e. if ambient pollution affects non-polluters (Spraggon, 2002, 2003) than under internal damage, i.e. if ambient pollution a¤ects polluters themselves (Cochard et al., 2005). Since these two types of experiments relied on very different designs, it is worthwhile to compare them under a common experimental design. Our main …nding is that the ambient tax is equally effcient under external damage than under internal damage.

Path computation in multi-layer networks: Complexity and algorithms

Carrier-grade networks comprise several layers where different protocols coexist. Nowadays, most of these networks have different control planes to manage routing on different layers, leading to a suboptimal use of the network resources and additional operational costs. However, some routers are able to encapsulate, decapsulate and convert protocols and act as a liaison between these layers. A unified control plane would be useful to optimize the use of the network resources and automate the routing configurations. Software-Defined Networking (SDN) based architectures, such as OpenFlow, offer a chance to design such a control plane. One of the most important problems to deal with in this design is the path computation process. Classical path computation algorithms cannot resolve the problem as they do not take into account encapsulations and conversions of protocols. In this paper, we propose algorithms to solve this problem and study several cases: Path computation without bandwidth constraint, under bandwidth constraint and under other Quality of Service constraints. We study the complexity and the scalability of our algorithms and evaluate their performances on real topologies. The results show that they outperform the previous ones proposed in the literature.Comment: IEEE INFOCOM 2016, Apr 2016, San Francisco, United States. To be published in IEEE INFOCOM 2016, \<http://infocom2016.ieee-infocom.org/\&g

A model of individual clustering with vanishing diffusion

17International audienceWe consider a model of individual clustering with two specific reproduction rates and small diffusion parameter in one space dimension. It consists of a drift-diffusion equation for the population density coupled to an elliptic equation for the velocity of individuals. We prove the convergence (in suitable topologies) of the solution of the problem to the unique solution of the limit transport problem, as the diffusion coefficient tends to zero

Global existence of solutions to a parabolic-elliptic chemotaxis system with critical degenerate diffusion

19 pagesInternational audienceAbstract: This paper is devoted to the analysis of non-negative solutions for a degenerate parabolic-elliptic Patlak-Keller-Segel system with critical nonlinear diffusion in a bounded domain with homogeneous Neumann boundary conditions. Our aim is to prove the existence of a global weak solution under a smallness condition on the mass of the initial data, there by completing previous results on nite blow-up for large masses. Under some higher regularity condition on solutions, the uniqueness of solutions is proved by using a classical duality technique

Prevalence and factors favoring overweight and obesity in Algerian child and adolescent; case of the population of Constantine / Algeria

AbstractBackground: Our objectives through this paper are multiple: to measure the prevalence of overweight and obesity in children between 5-11 years and in adolescents between 12-17 years; highlight the main causes that influence this phenomenon in children and adolescents under 18 years old; highlight the risk factors associated with overweight and obesity in these age groups; and finally, the policies to be applied to stop or curb this phenomenon.Methods: This is a descriptive, transversal survey which focused on a representative sample of children and adolescents during the month of July 2018. The study population consisted of 1022 children and adolescents aged 5 to 17 years, who frequent a municipal swimming pool located in the wilaya of Constantine / Algeria. These children and adolescents were selected by chance for a few days over the four weeks of July 2018. Information concerning the socio-demographic characteristics, eating habits and sedentary behavior for each individual was specified by means of a questionnaire. Results: Among the results of this study: overweight affects 14% of children between 5-11 years old, while with moderate obesity, it affects 4% of children in this age category; for adolescents aged 12-17 years, 17% of them are overweight, and 7% have moderate obesity; several factors contribute to gaining extra pounds (gender and age, some hereditary factors, eating habits and physical inactivity).Conclusion: Identifying the risk factors for overweight and obesity in children and adolescents under 18 years old, would help identify risky habits and behaviors in order to propose appropriate prevention measures. These measures should be included in a health education strategy and a health promotion strategy

Global existence of solutions to a parabolic-elliptic chemotaxis system with critical degenerate di ffusion

This paper is devoted to the analysis of non-negative solutions for a degenerate parabolic-elliptic Patlak-Keller-Segel system with critical nonlinear diffusion in a bounded domain with homogeneous Neumann boundary conditions. Our aim is to prove the existence of a global weak solution under a smallness condition on the mass of the initial data, there by completing previous results on nite blow-up for large masses. Under some higher regularity condition on solutions, the uniqueness of solutions is proved by using a classical duality technique.Comment: 19 page

The economic approach of road safety; unique objective and contradictory motivations!

Abstract: Although the topic is a multidisciplinary field, we will address, through this article, road safety from an angle, more or less economic. Thus, the scarcity of the human or material resources of the victims of the accident, the non-abundance of budgetary means allocated to mitigate the damage of the accident (hospital expenses, reimbursements of insurance companies, etc.), the efficiency of the choices to be learned by the public authorities to deal with the hecatomb and the socio-economic benefits of road users (individuals or companies), etc. are road safety issues that constitute, from near or far, a discipline that we can call "the economics of road safety".Through our analysis we arrived at these results: Although the objective of road safety is clear: "to save as much life as possible from the traffic hecatomb", the motivations of each stakeholder in a road safety are not homogeneous and can be even contradictory, that it is within the same group of actors or at the level of the society as a whole. Thus, the sources of this contradiction can be: cultural, social, economic, etc. which divides instead of gathering opinion of the different actors on questions like: the causes of the accident, the settlement of the prejudices of the insecurity road, the regulation which frames the road organization, the solutions to elaborate, of time to another, to improve the lives of road users. Finally, the rationality of our days is approached in an artificial way, restricted and limited by a cost-benefit approach peculiar to a modern, liberal and immoral society

IMPACT OF URBAN CITY SPRAWL ON THE IDENTITY OF SUBURBS AND RURAL AREAS

Urban sprawl is the rapid expansion of the city towards the suburbs and the countryside, and it happens for various reasons. The first one is of residential nature, and is a result of growing population density while others are of political, economic, and social nature. There is no doubt that the city\u27s encroachment towards the countryside and the emergence of new patterns of construction such as buildings and transportation networks have more drawbacks than advantages, in developing countries, especially in the absence of planning. This phenomenon causes the rise of real estate prices that leads to a change in the direction of its use while decreasing the green areas that are considered the lungs of cities and thus leading to environmental damage, pollution, and destruction of the countryside. This expansion also obliterates the identity and characteristics of the countryside, leading to the loss of its aesthetics and heritage. In addition, urban sprawl also threatens its original inhabitants and may force them to be displaced (force migration) due to the loss of their land, their lifestyle, and their work sometimes. The main aim of this research is: control or slow down the urban city sprawl, and preserve the countryside’s identity and its specificities. This urban encroachment can be controlled by administrative and legal methods, and in various sustainable ways, through planning based on academic and scientific studies including the issuance of laws to amend the investment ratio in the city and in the countryside. This strategy of this research will expose sustainable methods in order to develop and improve the economic return of rural areas by investing in a productive agricultural sector, or in a tourism sector that makes the countryside a destination for leisure and comfort for the city\u27s residents. On this basis, we can stop or slow down the encroachment of the city and preserve the social, environmental, aesthetic, and characteristics of the countryside