Conditioning diffusions with respect to partial observations

In this paper, we prove a result of equivalence in law between a diffusion conditioned with respect to partial observations and an auxiliary process. By partial observations we mean coordinates (or linear transformation) of the process at a finite collection of deterministic times. Apart from the theoritical interest, this result allows to simulate the conditioned diffusion through Monte Carlo's method, using the fact that the auxiliary process is easy to simulate

Technical Efficiency, Farm Size and Tropical Deforestation in the Brazilian Amazonian Forest

This paper analyses the impact of farm productivity as well as farm size on deforestation in Brazil. A two step econometric approach is adopted. A bootstrapped translog stochastic frontier that is a posteriori checked for functional consistency is used in order to estimate technical efficiency of which estimates are introduced in a land use model to assess the impact of productivity and farm size on deforestation. Analysis of agricultural census tract data suggests that technical efficiency has a nonlinear (convex) effect: less and more efficient farms use more land for agricultural activities and so they have a positive effect on deforestation. However, the majority of farms are on the ascendant slope so that efficiency implies more deforestation in Brazilian Legal Amazon. Moreover, farm size has a robust negative effect on deforestation. Contrary to many studies, this result suggests that small farms convert more natural (forested) land into agricultural land than large ones.Farm size;Stochastic frontier model;Brazil.;Land use model

Legal origin, colonial origin and deforestation

This paper investigates whether inherited legacies such as legal origin allow of explaining deforestation in 110 developed and developing countries. The hypothesis is that differences in deforestation between countries can be attributed to their legal systems. Also, since nearly all common law countries are former English colonies, and nearly all civil law countries were colonized by France, Spain or Portugal, legal origin and colonial history are strongly correlated, so that one can not attribute all the variance to the effect of the legal system. What is found overall is that (i) French civil law countries deforest less than English common law ones within the total sample, within the sample of colonized countries, and within the sample of tropical developing countries; (ii) Former French colonies deforest less than former English colonies. These results hold when geography features are controlled for since the process of colonization was not random and depended on initial geographic and climatic conditions.Deforestation; Colonial legacies; Legal origin

Moderate deviations for the chemical distance in Bernoulli percolation

In this paper, we establish moderate deviations for the chemical distance in Bernoulli percolation. The chemical distance between two points is the length of the shortest open path between these two points. Thus, we study the size of random fluctuations around the mean value, and also the asymptotic behavior of this mean value. The estimates we obtain improve our knowledge of the convergence to the asymptotic shape. Our proofs rely on concentration inequalities proved by Boucheron, Lugosi and Massart, and also on the approximation theory of subadditive functions initiated by Alexander.Comment: 19 pages, in english. A french version, entitled "D\'eviations mod\'er\'ees de la distance chimique" is also availabl

Technical Efficiency, Farm Size and Tropical Deforestation in the Brazilian Amazonian Forest

This paper analyses the impact of farm productivity as well as farm size on deforestation in Brazil. A two step econometric approach is adopted. A bootstrapped translog stochastic frontier that is a posteriori checked for functional consistency is used in order to estimate technical efficiency of which estimates are introduced in a land use model to assess the impact of productivity and farm size on deforestation. Analysis of agricultural census tract data suggests that technical efficiency has a nonlinear (convex) effect: less and more efficient farms use more land for agricultural activities and so they have a positive effect on deforestation. However, the majority of farms are on the ascendant slope so that efficiency implies more deforestation in Brazilian Legal Amazon. Moreover, farm size has a robust negative effect on deforestation. Contrary to many studies, this result suggests that small farms convert more natural (forested) land into agricultural land than large ones.Farm size, Stochastic frontier model, Brazil., Land use model

Legal origin, colonial origin and deforestation

This paper investigates whether inherited legacies such as legal origin allow of explaining deforestation in 110 developed and developing countries. The hypothesis is that differences in deforestation between countries can be attributed to their legal systems. Also, since nearly all common law countries are former English colonies, and nearly all civil law countries were colonized by France, Spain or Portugal, legal origin and colonial history are strongly correlated, so that one can not attribute all the variance to the effect of the legal system. What is found overall is that (i) French civil law countries deforest less than English common law ones within the total sample, within the sample of colonized countries, and within the sample of tropical developing countries; (ii) Former French colonies deforest less than former English colonies. These results hold when geography features are controlled for since the process of colonization was not random and depended on initial geographic and climatic conditions.Deforestation; Colonial legacies; Legal origin