Perforation or gap formation in a vegetation is a major process in landscape transformation. The occurrence of gaps profoundly alters the microclimatical conditions in a vegetation. A method is proposed to quantify perforation by using the three main 2-D characteristics of the gaps: area, number and boundary length. New measures are developed by normalizing the observed values to the reference status of minimum and maximum perforation. As minimum perforation status, the presence of one single gap with area equal to the (...) map resolution is assumed. The new measures are combined using a 3-D Euclidean distance to visualize the process and to detect changes. The method is exemplified using a field case of gaps in a tropical terra firme rainforest at Tiputini, Ecuador. (shrink)

In Apoll. Rh., Arg. IV, 477-479 Jason mutilates the corpse of Apsyrtus. To date, there has been a great deal of scholarly disagreement concerning the motive of this μασχαλισμός: either the mutilation was intended as a cathartic appeasement sacrifice, or its goal was to avert the vengeance of the victim’s ghost. This article opens up a new perspective by examining the ritual within the broader context of the fourth book of the epic. The appeasement motive is generally considered to have (...) originated with Apollonius. However, a contextual study shows that he meant to apply the vengeance motive. All the signs that indicate an appeasement sacrifice can be explained in other ways. Moreover, Apollonius more than once explicitly refers to the defilement of Medea and Jason. The conclusion is that Jason mutilated Apsyrtus in order to avert his vengeance, not to bring an offering of atonement.Dans Apoll. Rh., Arg. IV, 477-479, Jason mutile le corps d’Apsyrtos. Jusqu’à présent, le motif de ce μασχαλισμός a fait débat : ou bien la mutilation est vue comme une offrande expiatoire et cathartique, ou bien l’on considère que son objectif était d’éviter la vengeance de l’esprit de la victime. Cet article ouvre une nouvelle perspective en examinant le rite dans le contexte plus large de l’épopée d’Apollonios, qui semble être le point de départ du motif expiatoire. Néanmoins, une lecture contextuelle montre qu’il a plutôt tendu à appliquer le motif de la vengeance. Tous les signes indiquant un sacrifice expiatoire peuvent être expliqués d’une autre façon. En outre, Apollonios se réfère plusieurs fois explicitement à la souillure de Jason et Médée. Dès lors, il s’avère que Jason a mutilé Apsyrtos pour éviter sa vengeance et non pour offrir un sacrifice expiatoire. (shrink)