Search results for "TTC"
showing 6 items of 6 documents
Iron-loaded transferrin (Tf) is detrimental whereas iron-free Tf confers protection against brain ischemia by modifying blood Tf saturation and subse…
2018
Despite transferrin being the main circulating carrier of iron in body fluids, and iron overload conditions being known to worsen stroke outcome through reactive oxygen species (ROS)-induced damage, the contribution of blood transferrin saturation (TSAT) to stroke brain damage is unknown. The objective of this study was to obtain evidence on whether TSAT determines the impact of experimental ischemic stroke on brain damage and whether iron-free transferrin (apotransferrin, ATf)-induced reduction of TSAT is neuroprotective. We found that experimental ischemic stroke promoted an early extravasation of circulating iron-loaded transferrin (holotransferrin, HTf) to the ischemic brain parenchyma.…
Global flow impacts time-to-passage judgments based on local motion cues
2011
AbstractWe assessed the effect of the coherence of optic flow on time-to-passage judgments in order to investigate the strategies that observers use when local expansion information is reduced or lacking. In the standard display, we presented a cloud of dots whose image expanded consistent with constant observer motion. The dots themselves, however, did not expand and were thus devoid of object expansion cues. Only the separations between the dots expanded. Subjects had to judge which of two colored target dots, presented at different simulated depths and lateral displacements would pass them first. Image velocities of the target dots were chosen so as to correlate with time-to-passage only…
Estimation des Cartes du Temps de Collision (TTC) en Vision Para-catadioptrique
2013
National audience; Le temps de contact ou le temps de collision (TTC) est une information importante pour la navigation et l'évitement d'obtacles. Son estimation a largement été étudiée dans le cas des caméras perspectives. Par contre, très peu de travaux ont été effectués sur ce sujet pour les caméras catadioptriques, alors qu'elles sont très utiles, notamment, en navigation des robots mobiles. L'objectif de cet article, est de proposer un nouveau modèle d'estimation du TTC pour les caméras paracatadioptriques basé sur le flot optique, en adaptant celui développé pour les caméras perspectives. Le calcul du TTC en chaque pixel permet d'obtenir la carte des temps de collision. Nous avons val…
Ultrathin Tropical Tropopause Clouds (UTTCs): II. Stabilization mechanisms
2003
Abstract. Mechanisms by which subvisible cirrus clouds (SVCs) might contribute to dehydration close to the tropical tropopause are not well understood. Recently Ultrathin Tropical Tropopause Clouds (UTTCs) with optical depths around 10-4 have been detected in the western Indian ocean. These clouds cover thousands of square kilometers as 200-300 m thick distinct and homogeneous layer just below the tropical tropopause. In their condensed phase UTTCs contain only 1-5% of the total water, and essentially no nitric acid. A new cloud stabilization mechanism is required to explain this small fraction of the condensed water content in the clouds and their small vertical thickness. This work sugges…