903 research outputs found

    Maxillary canine/third premolar transposition in a prehistoric population from Santa Cruz Island California

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    Dates, Caries, and Early Tooth Loss During the Iron Age of Oman

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    Eine Ernährung aus fermentierbaren Kohlenhydraten ist bekannterweise hoch kariogen, besonders im Falle von zuckerhaltigem Essen wie zum Beispiel Datteln. Diese Ernährung ist bei der späteisenzeitlichen Samad-zeitlichen Bevölkerung Omans zu beobachten. 32 Erwachsene und 5 Jugendliche dienten für diese Studie als Erhebung. Vorzeitiger Zahnverlust war in allen Fällen nachweisbar

    An Integrated Architectural Element Approach to Three-Dimensional Geologic Mapping of the Huntertown Aquifer System In Northeastern Indiana

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    This poster was presented at the 2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM, October 5-9, Houston, TX.A three-dimensional geologic model of the Huntertown glacial aquifer system is being developed. Permeable hydrostratigraphic units within the Huntertown Formation (Quaternary) comprise the principal ground-water resource for an expanding population in northern Allen County, Indiana. The Huntertown aquifer system lies predominantly between the less permeable Lagro and Trafalgar Formations. The Huntertown Formation and corresponding aquifer system are located in an interlobate setting characterized by complex glacial stratigraphy, consisting of coarse-grained proglacial sediments and loamy till intercalated with glaciofluvial and glaciolacustrine facies. To construct the model, a database of more than 2,500 lithologic logs from public and private water supply wells and more than 200 down-hole natural gamma-ray logs was compiled for the study area (~500 km2). The lithologic logs were plotted to construct 110 hand-drawn cross sections (total length of about 900 km) that were used to map the bounding surfaces of the three formations (high-order architectural elements) as well as to constrain the scale and geometry of intratill sand and gravel aquifer units. The base of the Lagro Formation was determined from well logs by a shift from massive clays to loam-textured sediments or by the presence of laterally and vertically extensive underlying sand and gravel units. A prominent shift toward higher counts in natural gamma-ray profiles was also used to determine the base of the Lagro. The top of the Trafalgar Formation was defined by a ubiquitously present overlying outwash package depicted in gamma-ray logs or by lithologic descriptions reflecting the Trafalgar's overconsolidated nature. Previously mapped areal extents of hydrogeologic facies are currently being used in conjunction with both lithologic and natural gamma-ray cross sections, rendered at various orientations across the study area, to determine the geometry of individual morphosequences or lower-order architectural elements (e.g., ice marginal fans and outwash channels)

    Wind-US Code Physical Modeling Improvements to Complement Hypersonic Testing and Evaluation

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    This report gives an overview of physical modeling enhancements to the Wind-US flow solver which were made to improve the capabilities for simulation of hypersonic flows and the reliability of computations to complement hypersonic testing. The improvements include advanced turbulence models, a bypass transition model, a conjugate (or closely coupled to vehicle structure) conduction-convection heat transfer capability, and an upgraded high-speed combustion solver. A Mach 5 shock-wave boundary layer interaction problem is used to investigate the benefits of k- s and k-w based explicit algebraic stress turbulence models relative to linear two-equation models. The bypass transition model is validated using data from experiments for incompressible boundary layers and a Mach 7.9 cone flow. The conjugate heat transfer method is validated for a test case involving reacting H2-O2 rocket exhaust over cooled calorimeter panels. A dual-mode scramjet configuration is investigated using both a simplified 1-step kinetics mechanism and an 8-step mechanism. Additionally, variations in the turbulent Prandtl and Schmidt numbers are considered for this scramjet configuration

    Lamin B1 Depletion in Senescent Cells Triggers Large-Scale Changes in Gene Expression and the Chromatin Landscape

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    Senescence is a stable proliferation arrest, associated with an altered secretory pathway, thought to promote tumor suppression and tissue aging. While chromatin regulation and lamin B1 down-regulation have been implicated as senescence effectors, functional interactions between them are poorly understood. We compared genome-wide Lys4 trimethylation on histone H3 (H3K4me3) and H3K27me3 distributions between proliferating and senescent human cells and found dramatic differences in senescence, including large-scale domains of H3K4me3- and H3K27me3-enriched “mesas” and H3K27me3-depleted “canyons.” Mesas form at lamin B1-associated domains (LADs) in replicative senescence and oncogene-induced senescence and overlap DNA hypomethylation regions in cancer, suggesting that pre-malignant senescent chromatin changes foreshadow epigenetic cancer changes. Hutchinson-Gilford progeria syndrome fibroblasts (mutant lamin A) also show evidence of H3K4me3 mesas, suggesting a link between premature chromatin changes and accelerated cell senescence. Canyons mostly form between LADs and are enriched in genes and enhancers. H3K27me3 loss is correlated with up-regulation of key senescence genes, indicating a link between global chromatin changes and local gene expression regulation. Lamin B1 reduction in proliferating cells triggers senescence and formation of mesas and canyons. Our data illustrate profound chromatin reorganization during senescence and suggest that lamin B1 down-regulation in senescence is a key trigger of global and local chromatin changes that impact gene expression, aging, and cancer
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