61 research outputs found

    Armes

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    Préhistoire (G. Camps) Les armes des Paléoberbères de la Préhistoire ne présentent guère d’originalité mais à la documentation archéologique provenant de fouilles s’ajoute, en Afrique du Nord et au Sahara, une documentation iconographique d’une grande richesse que ne possèdent pas les autres pays riverains du bassin occidental de la Méditerranée. Durant les temps paléolithiques, les hommes qui occupèrent le Maghreb et le Sahara utilisèrent, en plus des outils et armes connus ailleurs ; biface..

    Impact of Climate Change on the Relict Tropical Fish Fauna of Central Sahara: Threat for the Survival of Adrar Mountains Fishes, Mauritania

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    Background: Four central Sahara mountainous massifs provide habitats for relict populations of fish. In the Adrar of Mauritania all available data on the presence and distribution of fish come from pre-1960 surveys where five fish species were reported: Barbus pobeguini, Barbus macrops, Barbus mirei, Sarotherodon galilaeus, and Clarias anguillaris. Since 1970, drought has had a severe impact in the Adrar where rainfall decreased by 35%. To investigate whether the relict populations of fish have survived the continuing drought, a study was carried out from 2004 to 2008. Methodology/Principal Findings: An inventory of perennial bodies of water was drawn up using a literature review and analysis of topographical and hydrological maps. Field surveys were carried out in order to locate the bodies of water described in the literature, identify the presence of fish, determine which species were present and estimate their abundance. The thirteen sites where the presence of fish was observed in the 1950s -Ksar Torchane, Ilij, Molomhar, Agueni, Tachot, Hamdoun, Terjit, Toungad, El Berbera, Timagazine, Dayet el Mbarek, Dayet et-Tefla, Nkedei-were located and surveyed. The Ksar Torchane spring -type locality and the only known locality of B. mirei- has dried up at the height of the drought in 1984, and any fish populations have since become extinct there. The Timagazine, Dayet el Mbarek and Dayet et-Tefla pools have become ephemeral. The Hamdoun guelta appears to be highly endangered. The fish populations at the other sites remain unchanged. Four perennial pools which are home to populations of B. pobeguini are newly recorded. Conclusion/Significance: The tropical relict fish populations of the Adrar mountains of Mauritania appear to be highly endangered. Of thirteen previously recorded populations, four have become extinct since the beginning of the drought period. New fish population extinctions may occur should low levels of annual rainfall be repeated

    Tactual perception: a review of experimental variables and procedures

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    This paper reviews literature on tactual perception. Throughout this review we will highlight some of the most relevant variables in touch literature: interaction between touch and other senses; type of stimuli, from abstract stimuli such as vibrations, to two- and three-dimensional stimuli, also considering concrete stimuli such as the relation between familiar and unfamiliar stimuli or the haptic perception of faces; type of participants, separating studies with blind participants, studies with children and adults, and an analysis of sex differences in performance; and finally, type of tactile exploration, considering conditions of active and passive touch, the relevance of movement in touch and the relation between exploration and time. This review intends to present an organised overview of the main variables in touch experiments, attending to the main findings described in literature, to guide the design of future works on tactual perception and memory.This work was funded by the Portuguese “Foundation for Science and Technology” through PhD scholarship SFRH/BD/35918/2007

    Calcium homeostasis and glucose uptake of murine myotubes exposed to insulin, caffeine and 4-chloro-m-cresol.

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    The modulation of glucose uptake by cytosolic calcium and the role of insulin on calcium homeostasis in insulin-target cells are incompletely understood and results are contradictory. To address this issue, we used the C2C12 murine skeletal muscle cell line model and examined the influence of caffeine and 4-chloro-m-cresol, two ryanodine receptor agonists known to mobilize intracellular calcium stores and increase cytosolic free calcium concentration. We followed 45calcium efflux, a validated indicator of cytosolic calcium concentration, and 3-O-methyl-[1-3H]-d-glucose uptake in parallel. We also determined if insulin incubation affected 45calcium influx rate. A 30-min treatment by 1 microm insulin highly significantly increased 45calcium efflux by 8.5% (P = 0.0014), despite a significant reduction of 45Ca2+ influx already measurable after 20 and 30 min of insulin stimulation (-16.6%, P = 0.0119 and -21.3%, P = 0.0047, respectively). Caffeine (1-20 mm) and 4-chloro-m-cresol (0.05-10 mm) concentration-dependently increased 45calcium efflux, the latter being more potent and efficacious. These agents, in a concentration-dependent manner, inhibited both basal and, more potently, insulin-stimulated glucose uptake. This resulted in a negative correlation of glucose uptake and 45calcium efflux (r > 0.95, P < 0.001). This effect was approximately 5 times greater for caffeine than for 4-chloro-m-cresol, suggesting a calcium-independent part of the glucose uptake inhibition by caffeine. In our in vitro model of cultured muscle cells, insulin appears to prevent calcium overload by both stimulating efflux and inhibiting cell storage. This effect, taken together with the observed inhibitory, inverse relationship between 45calcium efflux and glucose uptake, contributes to describing the complex insulin-calcium interplay involved in target cells

    Persistent risk of adult T-cell leukemia/lymphoma after neonatal HTLV-1 infection through exchange transfusion

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    A 36-year-old Caucasian male presented with adult T-cell leukemia/lymphoma (ATL). HTLV-1 contamination was attributed to a neonatal exchange transfusion. Remission was achieved but 11 years later he presented with symptoms suggesting ATL relapse. Molecular studies of T-cell clonality and virus integration sites revealed a clonal disease, distinct from the first tumor
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