Wave speed in noncircular collapsible ducts

The wave speed in initially elliptical collapsible tubes was studied. The celerity c of pressure waves of small amplitude was calculated from the numerically defined area-pressure law of the buckled cross section. In addition to the fact that the wave speed variation with transmural pressure was strongly dependent upon the initial eccentricity of the cross section, the wave speed value was found to be discontinuous at the contact pressure pc and reached a minimum on the right-hand side of the discontinuity. These results were compared with experimental data obtained in an annular duct.     

Our ancestors' ancestor: Ouranopithecus is a greek link in human ancestry

Recent discoveries of the late Miocene hominoid Ouranopithecus shed new light on the evolution of hominids. These discoveries result from the strategy of the Allied armies during the First World War. In the midst of “the war to end all wars,” the North African soldiers of Camille Arambourg excavated the first mammalian fossils found in northern Greece, in the region of Macedonia, the country of Alexander the Great. On the tracks of these strange paleontological pioneers, a modern French and Greek team has unearthed a large hominoid primate, a missing link between fossilapes and primitive Australopithecus, which lived in southeastern Europe 9 to 10 million years ago. A reconstruction of Ouranopithecus and its surroundings gives us a rare glimpse into the world of the earliest hominids.     

New material of Ouranopithecus macedoniensis from late Miocene of Macedonia (Greece) and study of its dental attrition

During the last five years our continued excavations in the known late Miocene mammal localities of Macedonia (Greece) provided several new specimens of the hominoid primate Ouranopithecus macedoniensis. This new material includes maxillary and mandibular remains and it is described and compared to the old material of Ouranopithecus in the present article. The material of Ouranopithecus from the three known localities “Ravin de la Pluie” (RPl), “Xirochori 1” (XIR) and “Nikiti 1” (NKT) includes a complete series of tooth rows representing all wearing stages. Thus, the study of the dental wear of Ouranopithecus upper and lower teeth is studied and compared to that of the recent hominoids Gorilla and Pan, as well as to Australopithecus afarensis. The latter species is well known by a series of tooth rows of different wearing stages. The canine’s attrition of Ouranopithecus has a more derived pattern than that of the recent hominoids (Gorilla and Pan) and less derived than A. afarensis. The p3 of Ouranopithecus has similar attrition to that of A. afarensis, the attrition of the molars in Ouranopithecus, A. afarensis and Pan follows a similar pattern, while in Gorilla it is different.     

A two-process theory of facial perception of emotions.

A two-process probabilistic theory of emotion perception based on a non-linear combination of facial features is presented. Assuming that the upper and the lower part of the face function as the building blocks at the basis of emotion perception, an empirical test is provided with fear and happiness as target emotions. Subjects were presented with prototypical fearful and happy faces and with computer-generated chimerical expressions that were a combination of happy and fearful. Subjects were asked to indicate the emotions they perceive using an extensive list of emotions. We show that some emotions require a conjunction of the two halves of a face to be perceived, whereas for some other emotions only one half is sufficient. We demonstrate that chimerical faces give rise to the perception of genuine emotions. The findings provide evidence that different combinations of the two halves of a fearful and a happy face, either congruent or not, do generate the perception of emotions other than fear and happiness.