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.     

Anxiety,Depression and Fraternal Experiences on the Birth Child in a Foster Home

If foster care primarily concerns foster children displaced from a family to another, it also constitutes a singular event for the entire family, including the children of the foster parents. The aim of this study was to examine anxiety and depressive symptoms in foster families’ birth children and to explore the statistical associations between the different types of horizontal relations (with a sibling or a foster child) and the psycho-affective equilibrium of the birth children. Self-evaluation scales on the quality of sibling relations, anxiety and depressive symptoms were used. Forty five birth adolescents, aged from 11 to 18 years old, took part in the study. These participants showed more balanced scores of anxiety and depression than the population of the same age. Post-hoc tests additionally suggest that these ones vary depending on the gender, possibly due to specific role expectations. The relations between siblings or with the foster child present differentiated outcomes on anxiety and depression scores. This study confirms that the quality of horizontal relations is important for the psycho-affective equilibrium of the birth child. The relationships between birth and foster children need to be more systematically considered in order to promote successful fostering.     

Functional convergence of quantile-type frontiers with application to parametric approximations

Nonparametric estimators of the upper boundary of the support of a multivariate distribution are very appealing because they rely on very few assumptions. But in productivity and efficiency analysis, this upper boundary is a production (or a cost) frontier and a parametric form for it allows for a richer economic interpretation of the production process under analysis. On the other hand, most of the parametric approaches rely on often too restrictive assumptions on the stochastic part of the model and are based on standard regression techniques fitting the shape of the center of the cloud of points rather than its boundary. To overcome these limitations, Florens and Simar [2005. Parametric approximations of nonparametric frontiers. J. Econometrics 124 (1), 91–116] propose a two-stage approach which tries to capture the shape of the cloud of points near its frontier by providing parametric approximations of a nonparametric frontier. In this paper we propose an alternative method using the nonparametric quantile-type frontiers introduced in Aragon, Daouia and Thomas-Agnan [2005. Nonparametric frontier estimation: a conditional quantile-based approach. Econometric Theory 21, 358–389] for the nonparametric part of our model. These quantile-type frontiers have the superiority of being more robust to extremes. Our main result concerns the functional convergence of the quantile-type frontier process. Then we provide convergence and asymptotic normality of the resulting estimators of the parametric approximation. The approach is illustrated through simulated and real data sets.     

A study of regression calibration in a partially observed stratified Cox model

Regression calibration is a simple method for estimating regression models when covariate data are missing for some study subjects. It consists in replacing an unobserved covariate by an estimator of its conditional expectation given available covariates. Regression calibration has recently been investigated in various regression models such as the linear, generalized linear, and proportional hazards models. The aim of this paper is to investigate the appropriateness of this method for estimating the stratified Cox regression model with missing values of the covariate defining the strata. Despite its practical relevance, this problem has not yet been discussed in the literature. Asymptotic distribution theory is developed for the regression calibration estimator in this setting. A simulation study is also conducted to investigate the properties of this estimator.     

Panel Unit Root Tests in the Presence of Cross-Sectional Dependencies: Comparison and Implications for Modelling

Several panel unit root tests that account for cross-section dependence using a common factor structure have been proposed in the literature recently. Pesaran's (2007 Pesaran , M. H. ( 2007 ). A simple panel unit root test in the presence of cross section dependence . Journal of Applied Econometrics 22 : 265 – 312 .[Crossref], [Web of Science ®] , [Google Scholar]) cross-sectionally augmented unit root tests are designed for cases where cross-sectional dependence is due to a single factor. The Moon and Perron (2004 Moon , H. R. , Perron , B. (2004). Testing for a unit root in panels with dynamic factors. Journal of Econometrics 122:81–126.[Crossref], [Web of Science ®] , [Google Scholar]) tests which use defactored data are similar in spirit but can account for multiple common factors. The Bai and Ng (2004a Bai , J. , Ng , S. ( 2004a ). A PANIC attack on unit roots and cointegration . Econometrica 72 : 1127 – 1177 .[Crossref], [Web of Science ®] , [Google Scholar]) tests allow to determine the source of nonstationarity by testing for unit roots in the common factors and the idiosyncratic factors separately. Breitung and Das (2008 Breitung , J. , Das , S. ( 2008 ). Testing for unit roots in panels with a factor structure . Econometric Theory 24 : 88 – 108 .[Crossref], [Web of Science ®] , [Google Scholar]) and Sul (2007 Sul , D. ( 2007 ) . Panel Unit Root Tests Under Cross Section Dependence with Recursive Mean Adjustment . Mimeo : University of Auckland . [Google Scholar]) propose panel unit root tests when cross-section dependence is present possibly due to common factors, but the common factor structure is not fully exploited.

This article makes four contributions: (1) it compares the testing procedures in terms of similarities and differences in the data generation process, tests, null, and alternative hypotheses considered, (2) using Monte Carlo results it compares the small sample properties of the tests in models with up to two common factors, (3) it provides an application which illustrates the use of the tests, and (4) finally, it discusses the use of the tests in modelling in general.     

Quality of Work Life: Theoretical and Methodological Problems, and Presentation of a New Model and Measuring Instrument

Purpose: Ever since the concept of Quality of Work Life (QWL) was first used over 30 years ago, a range of definitions and theoretical constructs have succeeded each other with the aim of mitigating the many problems facing the concept. A historical overview of the concept of QWL is presented here. Given the lack of consensus concerning the solutions that have been developed to date, a new definition of QWL is suggested, inspired by the research on a related concept, general Quality of Life (QOL) which, as the literature shows, has faced the same conceptualization and definition problems as QWL. Based on the suggested definition of QOL, a definition of QWL is provided and the measuring instrument that results therefrom (the Quality of Working Life Systemic Inventory – QWLSI) is presented. Finally, the solutions that this model and measuring instrument provide for the above-mentioned problems are discussed.     

French ‘savoir-faire’ in selling arms: A new way of doing business?

In this remarkable article the authors analyse the reasons for the success of the French arms industry. In particular they note the financial and technological support given by the French Government, the independent foreign policy which the government pursues and the technological innovation which French arms producers have consistently developed. They build a picture of close collaboration between the French Government and the arms industry and demonstrate how the French arms business has been able to create a virtual monopoly of certain market segments.     

Risk Perception and Social Acceptability of Technologies: The French Case

The authors present results of a February 1987 survey on judged frequency of mortality causes and risk perception of technologies in a representative sample of the French population. Although the French context is very different, and the impact of public controversies have been very limited on technological choices such as the nuclear energy program, strong similarities in risk perception of technologies are observed with results from U.S. surveys. Results, which could be worthwhile for other countries, suggest that risk perception is influenced by two different types of components. The first influence is the global feeling of "security" that society procures to its members. Such feeling depends on the individual's socioeconomic status, subjective state of health, and personal discomfort in daily life, and explains individual aversion to risk independently of the mortality causes or technologies involved. The second influence is the degree of perceived social legitimization of the activities involving risks. Risks of medical and transportation activities are strongly opposed to illegitimate risky behaviors (smoking, drugs, alcohol); technologies which have been an object of public debate (nuclear plants, the chemical industry, lead in gasoline) have an intermediate position reflecting the remaining uncertainties of public opinion about their risk–benefit balancing. Tentative conclusions for risk communication are proposed.