Etude de recouvrement de protheses orthopediques metalliques par des phosphates de calcium en utilisant la technique de precipitation a composition constante

Available at INIST (FR), Document Supply Service, under shelf-number : AR 15190 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueSIGLEFRFranc

Organic farming as a rational choice: Empirical investigations in environmental decision making

Based on a postal survey of farmers conducted in 2004 in Western Germany (n = 657), a rational choice model of the adoption of organic farming is tested. Using methods of direct utility measurement, rational choice (RC) theory is applied directly in the empirical study. By that, questionable assumptions on the variability of preferences and the type of preferences to use in RC explanations can be avoided. The results indicate that the subjectively expected utility model is well suited to explain the adoption of organic farming. Expectations on the development of operational characteristics of the farm and farmers’ daily work are at the core of the decision. Farmers especially consider aspects like pest and weed control, the development of yields or the use of chemical substances. While solely economic factors like prices and marketing are also important, these are subordinate to operational aspects. In addition, a moderate impact of environmental concern regarding the adoption of organic farming is observed. (author's abstract

Helminth infections in laying hens kept in organic free range systems in Germany

This study describes the spectrum and intensity of helminth infections in laying hens kept in organic production systems in Germany. A total of 740 laying hens from 18 organic free range farms were collected between 2007 and 2010. The hens were sacrificed and the gastrointestinal tracts were examined for the presence and intensity of helminth infections with standard parasitological methods. Three nematode (Ascaridia galli, Heterakis gallinarum, Capillaria spp) and four cestode (Raillietina cesticillus, Hymenolepis cantaniana, Hymenolepis carioca, Choanotaenia infundibulum) species were found. Almost all hens (99.6%, N=737) harboured at least one helminth species. Average worm burden per hen was 218.4 (SD=218.3) worms. The most prevalent species were the nematodes Heterakis gallinarum (98%) followed by Ascaridia gall (88%) and Capillaria spp. (75.3%). The overall prevalence of the cestodes was 24.9%. Total worm burden was significantly higher during the summer season when compared with animals slaughtered during winter season (254 vs. 191, P<0.0001). The most dominant helminth species was Heterakis gallinarum averaging 190 (SE = 9.8) worms per hen in the summer and 129 (SE = 8.7) in the winter season (P<0.0001). Average Ascaridia gall burden was 25 (SE = 2.0) in summer and 26 (SE = 1.7) in winter (P=0.1160). Risk of infection with any of the nematodes was 50% higher in summer compared to winter (Psi = 1.49, P<0.0319). Probability of infection with any of the tapeworm species was 3.5 times higher in summer than in winter (P<0.0001). It can be concluded that the vast majority of hens are subclinically infected with at least one helminth species. The prevalence as well as intensity of the helminth infections, particularly with tapeworms, considerably increases in summer. The results indicate that it is essential to adopt alternative control strategies in order to lower infection risk in organic production systems which are gaining popularity. (C) 2011 Elsevier B.V. All rights reserved