25 resultados para strong bones


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An interdisciplinary study was conducted at Qijurittuq (IbGk-3), an archaeological site located on Drayton Island along the eastern shore of Hudson Bay, Nunavik. Local Inuit made important contributions to the research. High school students participated in the field school, and elders shared their traditional knowledge. The elders expressed an interest in the source of the wood used to construct Qijurittuq's semi-subterranean dwellings, and this inspired us to expand our research in that direction. This interdisciplinary study included a reconstruction of the geomorphological and environmental history of Drayton Island, wood provenance and dendrochronology studies, research on house architecture and settlement patterns, and a zooarchaeological analysis. This paper synthesizes the preliminary results of this interdisciplinary investigation within the context of climate change. We discuss the persistence of semi-subterranean dwellings in eastern Hudson Bay long after they had been abandoned elsewhere. At Qijurittuq, their abandonment corresponds with the end of Little Ice Age. However, at the same time, the development of more permanent contact with Euro-Canadians was having a strong impact upon Inuit culture.

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Als im Frühsommer 1949 die ersten Pferdeschädel und Hundeknochen als Streufunde aus dem Barsbeker Moor bekannt wurden, war es wünschenswert, mit Hilfe der Pollenanalyse eine zeitliche Zuordnung zu versuchen. Auf diese Weise konnte unter Umständen wieder ein prähistorischer Horizont pollenanalytisch fixiert werden, da u.a. auch datierbare Keramikreste aus der römischen Kaiserzeit gefunden wurden. Die Analyse des aus der Stirnhöhle zweier Pferdeschädel entnommenen Materials ergab die beiden obersten in der Tabelle verzeichneten Pollenspektren. Bei der Untersuchung fiel auf, daß das Einschlußmaterial der Funde stark feinsandig und etwas tonig war. Auch der Finder gab an, daß die Knochen dem Sand, bis zu dem der Torfabbau niedergetrieben wurde, unmittelbar auflagen. Eine Bohrung, die am Westende des Torfstiches niedergebracht wurde, zeigte ebenfalls diese Zwischenschicht als deutliche Sandeinschwemmung. Diese wird noch einmal von grobdetritischen Flachwasser-Ablagerungen unterlagert.

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Global warming was reported to cause growth reductions in tropical shallow water corals in both, cooler and warmer, regions of the coral species range. This suggests regional adaptation with less heat-tolerant populations in cooler and more thermo-tolerant populations in warmer regions. Here, we investigated seasonal changes in the in situ metabolic performance of the widely distributed hermatypic coral Pocillopora verrucosa along 12 degrees latitudes featuring a steep temperature gradient between the northern (28.5 degrees N, 21-27 degrees C) and southern (16.5 degrees N, 28-33 degrees C) reaches of the Red Sea. Surprisingly, we found little indication for regional adaptation, but strong indications for high phenotypic plasticity: Calcification rates in two seasons (winter, summer) were found to be highest at 28-29 degrees C throughout all populations independent of their geographic location. Mucus release increased with temperature and nutrient supply, both being highest in the south. Genetic characterization of the coral host revealed low inter-regional variation and differences in the Symbiodinium clade composition only at the most northern and most southern region. This suggests variable acclimatization potential to ocean warming of coral populations across the Red Sea: high acclimatization potential in northern populations, but limited ability to cope with ocean warming in southern populations already existing at the upper thermal margin for corals

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Samples of recent to Miocene fish and marine mammal bones from the bottom of the Atlantic and Pacific Oceans and Miocene Maikop deposits (Transcaspian region) are studied by X-ray diffraction technique combined with chemical and energy-dispersive analyses. Changes of lattice parameters and chemical composition of bioapatite during fossilization and diagenesis suggest that development of skeletal apatite proceeds from dahllite-type hydroxyapatite to francolite-type carbonate-fluorapatite. It is assumed that jump-type transition from dahllite to francolite during initial fossilization reflects replacement of biogeochemical reactions in living organisms, which are subject to nonlinear laws of nonequilibrium thermodynamics, by physicochemical processes according to the linear equilibrium thermodynamics.

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Uranium and thorium contents, as well as their distribution patterns have been studied in biogenic phosphates from the Atlantic and Pacific Oceans. Differently lithified fish remains (bones, scales, teeth) and marine mammal bones (ribs, vertebras, earbones) collected from both reduced shelf sediments and oxidized pelagic ones have been analyzed. U content in the material varies from 0.7 to 700 ppm, and Th content - from <0.5 to 14 ppm. U/Th ratio varies from 0.16 to 400. Contents of both elements increase with lithification of biogenic phosphates. U concentration is more intense on shelves, whereas thorium concentration increases in pelagic areas. Partial positive correlation of U and Th with Fe and negative correlation of U with organic carbon are noted. The latter corresponds to higher lithification of biogenic phosphates. Calcium phosphate transformed from hydroxyapatite to fluorcarbonate-apatite is the main carrier of U, while transformed organic matter is a minor agent. Thorium is mainly bound with Fe.

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Effects of ocean acidification on Emiliania huxleyi strain RCC 1216 (calcifying, diploid life-cycle stage) and RCC 1217 (non-calcifying, haploid life-cycle stage) were investigated by measuring growth, elemental composition, and production rates under different pCO2 levels (380 and 950 µatm). In these differently acclimated cells, the photosynthetic carbon source was assessed by a (14)C disequilibrium assay, conducted over a range of ecologically relevant pH values (7.9-8.7). In agreement with previous studies, we observed decreased calcification and stimulated biomass production in diploid cells under high pCO2, but no CO2-dependent changes in biomass production for haploid cells. In both life-cycle stages, the relative contributions of CO2 and HCO3 (-) uptake depended strongly on the assay pH. At pH values =< 8.1, cells preferentially used CO2 (>= 90 % CO2), whereas at pH values >= 8.3, cells progressively increased the fraction of HCO3 (-) uptake (~45 % CO2 at pH 8.7 in diploid cells; ~55 % CO2 at pH 8.5 in haploid cells). In contrast to the short-term effect of the assay pH, the pCO2 acclimation history had no significant effect on the carbon uptake behavior. A numerical sensitivity study confirmed that the pH-modification in the (14)C disequilibrium method yields reliable results, provided that model parameters (e.g., pH, temperature) are kept within typical measurement uncertainties. Our results demonstrate a high plasticity of E. huxleyi to rapidly adjust carbon acquisition to the external carbon supply and/or pH, and provide an explanation for the paradoxical observation of high CO2 sensitivity despite the apparently high HCO3 (-) usage seen in previous studies.