Databases dedicated to molecular biology are an essential complement to literature data. Today there is a very wide variety of heterogeneous databases. This diversity is, of course, explained by the variety of biological data, which are not limited to sequences, but also by the variety of objectives which governed their design. The major problem in the management of biological data therefore does not result so much from their volume as from this heterogeneity, both in terms of nature and format. The fundamental question is therefore how to integrate these biological data in order to make them...

The population occupies, in the hierarchy of life, an intermediate level between that of individuals and that of communities. We can define a population as a set of individuals of the same species who share a common habitat (and a community as a set of populations of different species, sharing a common habitat). Under these two apparently simple criteria (conspecificity, cohabitation) lies in fact a vast potential often complex interactions, linked in particular to the needs of reproduction, the inevitability of competition, or even the opportunities for cooperation.The study of populations...

L'érosion hydrique des sols constitue un aspect majeur de la dégradation des paysages dans les environnements méditerranéens sub-humides à semi-arides. Ce problème n'a pas été traité d'une manière détaillée au Algérie bien qu'il affecte de larges zones. L'objectif de cette étude est de développer une méthodologie utilisant la télédétection, le modèle numérique du terrain (MNT) et les systèmes d'information géographique (SIG) pour cartographier les zones à risque d'érosion hydrique dans le cadre du territoire de la wilaya de Saida et de produire une carte de risque qui...

Ce volume est une description des principes et de l'objectif de la cartographie de la végétation à l'échelle de l'unité paysagère. Le processus de cartographie repose sur les principes de la phytosociologie. On distingue quatre unités végétales typologiques emboîtées, de la communauté végétale à la cellule paysagère, de la série à la géosérie de végétation. La cartographie vise à délimiter en priorité les cellules du paysage et à les relier à une typologie d'habitat connue. Avant de commencer la cartographie d'un territoire, il est essentiel d'avoir une bonne...

Dieser Band beschreibt die Prinzipien und den Zweck der Vegetationskartierung auf der Ebene der Landschaftseinheit. Der Kartierungsprozess basiert auf den Grundsätzen der Pflanzensoziologie. Wedistinguish four nested typological vegetation units, from the plant community to the landscape cell,from the series to the vegetation geoseries. Mapping aims to delimit landscape cells as a priority andto relate them to a known habitat typology.Before the start of the mapping of an area, it is essential to have a good knowledge of thevegetation units that are present. In diesem Zusammenhang sind die...

Silviculture is the art and science of cultivating forests to improve their production, quality, health and productivity, while forestry is the set of operations involved in harvesting the raw timber produced by silviculture. These two activities are complementary and constitute the first stage in the timber industry, ranging from management to the production of raw timber for various uses. Logging is the set of operations aimed at harvesting timber, from felling trees to transporting logs to sawmills or processing plants. It is an essential activity for wood supply and forest management,...