Local perception of rodent-associated problems in Sahelian urban areas: a survey in Niamey,Niger

Rodents are involved in the epidemiology of many pathogens and are major pests for agriculture. Local perception and beliefs about rodents and their damages is a key element of control programs. We here present the first survey focusing on the human perception of rodent-associated problems in an African town, namely Niamey, Niger. In total, 170 interviews were conducted in 18 different urban districts where rodents (Mastomys natalensis, Rattus rattus and Mus musculus) are widespread and abundant. Rodent-associated problems were mentioned in almost all instances (96.5 %). Eight different categories of rodent-induced nuisances could be recurrently identified. The most frequently cited one consists in damages on food and food stocks (63.1 %), followed by damages on houses (47.3 %), furniture (19.5 %) and clothes (16.8 %). There was no significant association between damages and districts, which means that the perception of rodent-associated problems did not vary significantly across the city. Our survey strongly suggests that rodents may represent major pests not only for farmers, but also for inhabitants of towns, thus contributing to reinforce economic vulnerability. Finally, no mention of sanitary or medical problems was ever recorded during our survey, thus pointing towards an apparent absence of knowledge about the potential role of rodents in some public health issues.     

Managing urban growth and development in the Riyadh metropolitan area, Saudi Arabia

The paper examines public sector management of urban growth and development in the Riyadh Metropolitan Area, Saudi Arabia. The focus of the paper is on institutional capacity building and development intervention. The paper traces changes in public sector management structures and development activities over the history of the city with the aim of assessing development impact and identifying forces that have shaped the evolving state of urban management. The paper notes that urban management has significantly improved with time but the persistence of urban problems coupled with projections of future growth point to the need for further improvements. The paper, in conclusion, while acknowledging the utility of the metropolitan development strategy (MEDSTAR) being formulated for the city, points to the need for broader administrative reform to improve the ability to cope with long-term challenges of growth in the city. Some issues that reform could address are suggested.     

Regularized Bayesian quantile regression

A number of nonstationary models have been developed to estimate extreme events as function of covariates. A quantile regression (QR) model is a statistical approach intended to estimate and conduct inference about the conditional quantile functions. In this article, we focus on the simultaneous variable selection and parameter estimation through penalized quantile regression. We conducted a comparison of regularized Quantile Regression model with B-Splines in Bayesian framework. Regularization is based on penalty and aims to favor parsimonious model, especially in the case of large dimension space. The prior distributions related to the penalties are detailed. Five penalties (Lasso, Ridge, SCAD0, SCAD1 and SCAD2) are considered with their equivalent expressions in Bayesian framework. The regularized quantile estimates are then compared to the maximum likelihood estimates with respect to the sample size. A Markov Chain Monte Carlo (MCMC) algorithms are developed for each hierarchical model to simulate the conditional posterior distribution of the quantiles. Results indicate that the SCAD0 and Lasso have the best performance for quantile estimation according to Relative Mean Biais (RMB) and the Relative Mean-Error (RME) criteria, especially in the case of heavy distributed errors. A case study of the annual maximum precipitation at Charlo, Eastern Canada, with the Pacific North Atlantic climate index as covariate is presented.