Sites of past human activity were investigated to assess the visual recovery of the desert pavement following impacts from human trampling and vehicle traffic. Visually disturbed and nearby control sites were assessed using comparative photographic records, a field-based Visual Site Assessment, and Desert Pavement Recovery Assessment. Sites included: vehicle and walking tracks at Marble Point and Taylor Valley; a campsite, experimental treading trial site, and vehicle tracks in Wright Valley; and vehicle and walking tracks at Cape Roberts. The time since last disturbance ranged from three months to over 50 years. This investigation also attempted to determine what has the greatest lasting visual impact on soil surfaces in the Ross Sea region: dispersed trafficking or track formation? Walking tracks remained visible in the landscape (due to larger clasts concentrating along track margins) long after the desert pavement surface had recovered. However, randomly dispersed footprints were undetectable within five years. For many sites, allowing widespread trampling will give lower medium-term visible impact than concentrating traffic flow by track formation. For steep slopes and sites where repeated visits occur, use of a single track is recommended. Some 1950s vehicle tracks remain visible in the Antarctic landscape, but where visually obvious impacts were remediated, evidence of former occupation was almost undetectable.

Cette contribution décrit les objectifs, méthodes et résultats de plus de vingt années de recherches à l’Université de Limoges sur l’interaction rayonnement-matière. Les aspects fondamentaux et les applications à la détection et la dosimétrie sont abordés. D’autres sujets, tels que la modification des propriétés optiques des matériaux sous irradiation et les applications à l’optique intégrée ne sont que survolés. Sur le sujet de la détection des rayonnements, les auteurs partent de l’utilisation des polymères en tant de détecteurs pour aboutir à l’électronique intégrée. La conception des circuits intégrés silicium dédiés à la détection, la caractérisation et la dosimétrie des neutrons est décrite. On explique également comment la conception et la technologie du circuit intégré (capteur et électronique de traitement du signal) sont fortement dépendantes de l’interaction des neutrons. La nécessité d’associer une spectrométrie à la dosimétrie des neutrons est mise en évidence, et l’étude d’une solution globale basée sur un détecteur sandwich est détaillée car elle n’a jamais été publiée. Finalement, l’implication du laboratoire dans l’étude de la dissémination des radioéléments naturels en environnement liée aux activités passées des mines d’uranium est abordée. Le développement d’activités de mesure et d’expertise de radioactivité et de rayonnements nucléaires dans le cadre de la norme ISO 17025 et sous accréditation COFRAC est enfin décrit.

An objective multivariate technique is described for identification of individual tigers Panthera tigris from their pugmarks. Tracings and photographs of hind pugmarks were obtained from 23 pugmark-sets of 19 individually known tigers (17 wild and two captive tigers). These 23 pugmark-sets were then divided into two groups, one of 15 pugmark-sets for model building and another of eight pugmark-sets for model testing and validation. A total of 93 measurements were taken from each pugmark along with three gait measurements. We used CV ratio, F-ratio and removed highly correlated variables to finally select 11 variables from these 93 variables. These 11 variables did not differ between left and right pugmarks. Stepwise discriminant function analysis (DFA) based on these 11 variables correctly classified pugmark-sets to individual tigers. A realistic population estimation exercise was simulated using the validation dataset. The algorithms developed here correctly allocated each pugmark-set to the correct individual tiger. The effect of extraneous factors, i.e. soil depth and multiple tracers, was also tested and pugmark tracings compared with pugmark photographs. We recommend collecting pugmarks from soil depths ranging between 0.5 and 1.0 cm, and advocate the use of pugmark photographs rather than pugmark tracings to eliminate the chance of obtaining substandard data from untrained tracers. Our study suggests that tigers can be individually identified from their pugmarks with a high level of accuracy and pugmark-sets could be used for population estimation of tigers within a statistically designed mark–recapture framework.

A new survey and spatial analysis enables the author to argue that inland examples of Easter Island’s famous stone statues were not in transport to the coast but mark out ancient territories proposed by ethnologist Katherine Routledge in 1919.

Numerous footprints of dinosaurs, pterosaurs and birds, together with arthropod tracks, have been discovered in the upper Cretaceous Uhangri Formation which crops out along the south-western coastline of South Korea. This ichnofauna contains the first pterosaur tracks reported from Asia. The digitigrade tridactyl manus impressions exhibit features of a typical pterosaur hand print. The pes impressions, however, show features that are different from pterosaur footprints reported previously: there is no visible trace of impressions of individual digits, and the toes are triangular or rounded in shape distally without distinct claw impressions. As these features clearly distinguish the Uhangri tracks from Pteraichnus and Purbeckopus, we assign them to a new genus, Haenamichnus which accommodates the new ichnospecies, Haenamichnus uhangriensis. The prints are five to six times larger than those of Pteraichnus, and are currently the largest pterosaur ichnites known. They show virtually no trace of the 5th phalange of the pes, indicating that they were made by pterodactyloids; moreover, features of the tracks suggest that they can be attributed to azhdarchids, the commonest pterosaur of the Late Cretaceous. The longest pterosaur trackway yet known from any track site (length 7.3 m) and consisting of 14 pairs of foot impressions, was also found in the Uhangri Formation and suggests that azhdarchids, at least, were competent terrestrial locomotors. The fossil track site at Uhangri represents the first occurrence of the tracks of pterosaurs, dinosaurs and web-footed birds all on the same level. This demonstrates that pterosaurs and birds visited the same habitat, but the large size disparity suggests that they occupied different ecological niches.