Abstract: A device for creating a specific but temporary aquatic passage in an artificial or natural river. The device includes bases which rest on the bottom of a river and elements which extend upwardly from the bases. The bases have holes formed therein which receive rods that extend downwardly from the elements. Placement of the bases in the river bed, and subsequent installation of elements into the bases, allows obstacles to be created in the river which are desirable for canoeing and kayaking.

Abstract: Composition for the treatment of acne containing a dispersion of vesicles of ionic or non-ionic amphiphilic lipids, the vesicles containing in the lipid phase at least one salicylic acid derivative of formula (I): ##STR1## in which R represents a linear or branched C.sub.11 -C.sub.17 alkyl radical; R'.sub.1, R'.sub.2, R'.sub.3, which are identical or different, represent a C.sub.1 -C.sub.18 alkyl or hydroxyalkyl radical, it being possible for one of the radicals R'.sub.1, R'.sub.2 or R'.sub.3 to be a benzyl radical. The derivative of formula (I) serves both as charged lipid and as anti-acne active ingredient. The derivatives of formula (I) in which, when R represents a C.sub.13 -C.sub.17 alkyl radical, R'.sub.1, R'.sub.2, R'.sub.3, when they are identical, do not represent a hydroxyethyl radical.