Paleobiological Perspectives on the Early Upper Paleolithic Human Transition in the Northwestern Old World

Le consensus selon lequel l’expansion des Hommes modernes en Europe et Asia de l’ouest au début du Paléolithique supérieur a nécessité des degrés variables, chronologiquement et géographiquement, de métissage entre les Néandertaliens et ces Hommes modernes, fournit un cadre nouveau pour évaluer la mosaïque des changements bio-comportementaux qui eurent lieu durant cette période. En dépit d’une série de similitudes paléo-biologiques concernant les capacités cognitives, le système masticateur et la locomotion, et également d’un chevauchement chronologique entre ces deux groupes et de pratiques culturelles voisines, il existe des différences au niveau de la dentition antérieure, du membre supérieur, de l’architecture fémorale, des stresses, des profils démographiques et des isotopes stables. Elles reflètent principalement les améliorations des stratégies de subsistance et de la maîtrise technologique au début du Paléolithique supérieur. Mais, des données prouvent aussi que ces changements bio-comportementaux ont débuté avec les derniers Néandertaliens au début du Paléolithique supérieur.The emerging consensus that the emergence of modern humans in the northwestern Old World involved temporally and geographically varying degrees of admixture between Neandertals and early modern humans within the early Upper Paleolithic provides the framework for assessing the complex mosaic of biobehavioral changes which took place across the transition. Despite a series of paleobiological similarities involving cognitive, masticatory and locomotor behaviors, as well as temporal and cultural overlap between the two groups, there remain contrasts in the anterior dentition, the upper limb, femoral structural patterns, stress levels, demographic profiles and stable isotopes. These changes reflect principally the improvements in technology and subsistence of the earlier Upper Paleolithic. Moreover, there are indications that the biobehavioral shift started within the initial Upper Paleolithic Neandertals

Diffusion basis spectrum imaging for identifying pathologies in MS subtypes

Diffusion basis spectrum imaging (DBSI) combines discrete anisotropic diffusion tensors and the spectrum of isotropic diffusion tensors to model the underlying multiple sclerosis (MS) pathologies. We used clinical MS subtypes as a surrogate of underlying pathologies to assess DBSI as a biomarker of pathology in 55 individuals with MS. Restricted isotropic fraction (reflecting cellularity) and fiber fraction (representing apparent axonal density) were the most important DBSI metrics to classify MS using brain white matter lesions. These DBSI metrics outperformed lesion volume. When analyzing the normal-appearing corpus callosum, the most significant DBSI metrics were fiber fraction, radial diffusivity (reflecting myelination), and nonrestricted isotropic fraction (representing edema). This study provides preliminary evidence supporting the ability of DBSI as a potential noninvasive biomarker of MS neuropathology

New discoveries of Middle Paleolithic human remains from the “Bau de l'Aubésier (Vaucluse, France)”

Excavations in Middle Paleolithic levels at the “Bau de l’Aubésier (Vaucluse)” during 2000 yielded a maxillary molar and a partial mandible from late Middle Pleistocene levels, plus a maxillary molar from the early Late Pleistocene. The Middle Pleistocene remains (Aubesier 10 and 11) have close morphological affinities to contemporaneous European human remains, and the Neandertal molar (Aubesier 12) falls well within Neandertal ranges of variation. The teeth are notable for a toothpick groove on Aubesier 10 and the large dental caries in Aubesier 12. The Aubesier 11 mandible exhibits extensive pathological alterations of the alveolar process, indicating serious impairment of mastication.Des fouilles dans les niveaux du Paléolithique moyen du Bau de l’Aubésier (Vaucluse) en 2000 ont livré une molaire supérieure et une grande partie d’une mandibule des niveaux du Pléistocène moyen tardif ainsi qu’une molaire supérieure du début du Pléistocène supérieure. Les restes du Pléistocène moyen (Aubésier 10 et 11) ont des affinités morphologiques avec les autres restes humains contemporaines d’Europe, et la molaire néandertalienne (Aubésier 12) est bien dans la variation des Néandertaliens. Sur Aubésier 10 se remarque un sulcus de cure-dent, ainsi qu’une grande carie dentaire sur Aubésier 12. La mandibule Aubésier 11 montre des altérations pathologiques au niveaux des alvéoles, ce qui indique une mastication difficile

In vitro model suggests oxidative stress involved in keratoconus disease

Keratoconus (KC) affects 1:2000 people and is a disorder where cornea thins and assumes a conical shape. Advanced KC requires surgery to maintain vision. The role of oxidative stress in KC remains unclear. We aimed to identify oxidative stress levels between human corneal keratocytes (HCKs), fibroblasts (HCFs) and keratoconus cells (HKCs). Cells were cultured in 2D and 3D systems. Vitamin C (VitC) and TGF-β3 (T3) were used for 4 weeks to stimulate self-assembled extracellular matrix (ECM). No T3 used as controls. Samples were analyzed using qRT-PCR and metabolomics. qRT-PCR data showed low levels of collagen I and V, as well as keratocan for HKCs, indicating differentiation to a myofibroblast phenotype. Collagen type III, a marker for fibrosis, was up regulated in HKCs. We robustly detected more than 150 metabolites of the targeted 250 by LC-MS/MS per condition and among those metabolites several were related to oxidative stress. Lactate levels, lactate/malate and lactate/pyruvate ratios were elevated in HKCs, while arginine and glutathione/oxidized glutathione ratio were reduced. Similar patterns found in both 2D and 3D. Our data shows that fibroblasts exhibit enhanced oxidative stress compared to keratocytes. Furthermore the HKC cells exhibit the greatest level suggesting they may have a myofibroblast phenotype

Coulomb Explosion and Thermal Spikes

A fast ion penetrating a solid creates a track of excitations. This can produce displacements seen as an etched track, a process initially used to detect energetic particles but now used to alter materials. From the seminal papers by Fleischer et al. [Phys. Rev. 156, 353 (1967)] to the present [C. Trautmann, S. Klaumunzer and H. Trinkaus, Phys. Rev. Lett. 85, 3648 (2000)], `Coulomb explosion' and thermal spike models are treated as conflicting models for describing ion track effects. Here molecular dynamics simulations of electronic-sputtering, a surface manifestation of ion track formation, show that `Coulomb explosion' produces a `heat' spike so that these are early and late aspects of the same process. Therefore, differences in scaling are due to the use of incomplete spike models.Comment: Submitted to PRL. 4 pages, 3 figures. For related movies see: http://dirac.ms.virginia.edu/~emb3t/coulomb/coulomb.html PACS added in new versio

Improved semiclassical density matrix: taming caustics

We present a simple method to deal with caustics in the semiclassical approximation to the thermal density matrix of a particle moving on the line. For simplicity, only its diagonal elements are considered. The only ingredient we require is the knowledge of the extrema of the Euclidean action. The procedure makes use of complex trajectories, and is applied to the quartic double-well potential.Comment: 20 pages, 7 figures. Revised version, accepted for publication in Phys. Rev.