Abstract:The accuracy of ten methods of scaling (Smalian, Huber, Newton, Neloï d, paraboloid, cone, paracone, cylinder, truncated cone and truncated Neloï d) was evaluated on logs of 0.5, 1, 2 and 3 m cut to different heights of 27 teak trees. For this purpose, the volumes estimated by the ten formulas were compared with real volumes obtained by the technique of xylometer. The results obtained showed that the method of Huber was more efficient to calculate the volume of logs throughout the stem when the length was 0.5 m. For the other length logs, it was also the best formula when the logs came from the base of the stem. The formulas of Newton and Smalian gave in the center and top of the stem, in the case of 1 m and 2 m logs, relatively similar results and were better than other methods of scaling. As might be expected, the dendrometric method (cylinder, paraboloid, Neloï d, cone) gave worse results regardless of the length of logs considered. With logs of 0.5, 1, 2 and 3 m long, truncated forms of cone and Neloï d could also be used without significant errors in estimating the volume of teak logs. The model scaling obtained for the entire tree OPEN ACCESS Diversity 2013, 5 100 expresses the logarithm of the volume against the logarithm of the diameter and the logarithm of height.
RESUMEPour promouvoir la pisciculture de Tilapia guineensis, une étude comparée de ses performances biologiques, zootechniques et nutritionnelles a été réalisée. Les poissons étudiés ont été pêchés dans le milieu naturel et dans deux étangs d'élevage. Les données physicochimiques et biologiques des différents milieux ainsi que les caractéristiques zootechniques et nutritionnelles des poissons échantillonnés ont été collectées. Les résultats obtenus montrent que les paramètres physicochimiques enregistrés sont conformes aux normes écologiques recommandées pour l'espèce. Les données de production primaire (Chlorophylle a) indiquent une plus forte productivité des étangs (384,71 µgl -1 et 603,19 µgl -1 respectivement dans l'étang extensif et l'étang semi intensif) comparativement au milieu naturel (14,49 µgl -1 ). Quant aux caractéristiques zootechniques, la croissance était de type allométrique (b<3) dans les trois milieux. Le contenu stomacal des individus provenant des trois milieux montre une prédominance des particules macroscopiques (63 à 79% du volume d'estomac) comparativement aux particules microscopiques (21 à 37%). Le phytoplancton, le zooplancton, les débris végétaux, les macroinvertébrées, les grains de sables, etc., ont été identifiés comme étant des constituants naturels de l'estomac de T. guineensis. Seule la teneur corporelle en lipide des échantillons a varié selon le milieu de capture.
A nimal demography is an important component of the productivity of animal populations. In developing countries, collecting data in the field is perceived as a difficult task due to the dispersal and mobility of herds and the fact that pastoralists do not keep written records of their herds (Lesnoff, 2009). However, it is useful to be able to quantify this demography in the field according to the types of farms, for example to assess their productive potential (number of animals that can be capitalized or exploited by farmers each year) or the impact of a shock (epidemic, drought) or a technical innovation or for the orientation of political decisions and research programs. In Benin, reports pertaining to describe the functioning of cattle farms in rural areas are poorly available or are only found in old references (Dehoux and Hounsou-Vè, 1993). Thus, a renewed interest in our livestock systems is gradually manifested in the objective of better evaluating the areas and potential for improving cattle farms (Youssao et al.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.