From Photography to Cinematography: Recording Movement and Gait in a Neurological Context

The major challenge of photography has been freezing movement, to transform it into a fixed image or series of images. Very soon, photographers became interested in movement itself and tried to use photography as a tool to analyze movement. At the early stages, physicians interested in movement, perhaps surprisingly, made important technical contributions. Mécanisme de la physionomie humaine, by Duchenne, the first book with physiological experiments illustrated by photographs, is a landmark in this historical development. At the Salpêtrière, thanks to Charcot, photography officially entered clinical neurology. Medical journals with photographs were actively developed by Bourneville. Londe established a clinical photographic laboratory and published the first book on medical photography. The study of animal and human movement by Muybridge and Marey in the 1880s led to chronophotography and later cinematography. Clinicians such as Dercum and Richer took advantage of these new techniques to study pathological movement and gait in neurological diseases.     

Strontium isotope ratios in fossil teeth from South Africa: assessing laser ablation MC-ICP-MS analysis and the extent of diagenesis

This study tests the precision and accuracy of laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) for measuring strontium isotope ratios (⁸⁷Sr/⁸⁶Sr) in fossil teeth from Swartkrans and Sterkfontein in South Africa, and explores the extent of diagenesis in these specimens. Compared to solution MC-ICP-MS or thermal ionization mass spectrometry (TIMS) methods, LA-MC-ICP-MS can be faster and less expensive, but has lower precision and accuracy. We found that ⁸⁷Sr/⁸⁶Sr ratios in fossil rodent teeth measured by LA-MC-ICP-MS were offset from solution values by a mean of 0.0005 ± 0.0010 (2σ). Because of the very wide spread of biologically available ⁸⁷Sr/⁸⁶Sr ratios (∼0.710 to ∼0.790) in the region, LA-MC-ICP-MS is more than sufficient for assessing the geographic origins of the fossil rodents. The concentration of strontium in modern and fossil enamel from the area is statistically indistinguishable, as is the range of ⁸⁷Sr/⁸⁶Sr ratios in modern rodents and fossil rodents from Swartkrans. Thus, there is little evidence of diagenetic Sr in the fossil enamel. In contrast, the fossil dentine may contain up to ∼50% diagenetic strontium, although many dentine ⁸⁷Sr/⁸⁶Sr ratios are still far removed from the background cave value of 0.729. We propose that LA-MC-ICP-MS will also be of use for investigating the geographic origins of other, non-rodent fossil teeth from the Sterkfontein and Swartkrans collections, and may prove of similar utility at other suitable sites.     

Une morphologie de la circulation des savoirs la revue depuis 1800

The statistical survey of 1 385 french titles, starting with annales, journal or revue, helps to understand the development of “scientific” journals in France from the beginning of the 19^th century until today. This 200 years history provides perspectives about the growth and decline of publishing. It includes scientific titles within the publishing production and underscores the importance of stimulation of the flow of ideas and information, through frequency and growth analysis.     

ESR dose response of Al center measured in quartz samples from the Yellow River (China): Implications for the dating of Upper Pleistocene sediment

The ESR dating method requires to describe the evolution of the ESR signal intensities vs. increasing gamma doses, then to extrapolate the equivalent dose of radiation received by the sample since its deposition using mathematical fitting. The function classically used to describe the growth curves of ESR aluminium signal in quartz was recently discussed and challenged for Lower Pleistocene sediments. In the present work, some alluvial sediments sampled in Upper Pleistocene fluvial terraces of the Yellow River system (China) permit us to test the application of another extrapolation function (linear + exponential) recently proposed for Lower Pleistocene sediments. The equivalent doses obtained here for the recent deposits of the Yellow River system and the corresponding ages are promising and indicate the potential of ESR to date quartz deposits from Upper Pleistocene times.