The invention relates to a tensioning system of a traction mechanism to which a hydraulic fluid is applied and which interacts with a tensioning rail. The folding assembly is supplied with packs, each having an axis and, at one end and on opposite sides of the axis, two end portions which are folded to form the gable portion, with the end portions having, respectively, a first and a second portion to be folded, which are joined by a lateral face of the pack. The invention further relates to screening methods for identifying agonists and antagonists of BAIT activity. A boom has a first end pivotally attached by a second knuckle to an upper end of the mast.