500 research outputs found

    Calcium buffering is required to maintain bone stiffness in saline solution

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    This work determined whether mineral dissolution due to prolonged testing or storage of bone s~\u27imens in normal salint: would alter Lheir elastic modulus. In one experiment, small pieces of equine third metacarpal bone were soaked in normal saline supplemented with varying amounts of CaCI1. Changing Ca ion concentrations in the bath were monitored and the equilibrium concentration was determined. In a second experiment, the elastic moduli of twenty 4 x 10 x 100 mm equine third metacarpal beams were determined non-destructively in four-point bending. Half the beams were then soaked for 10 days in normal saline, and the other half in saline buffered to the bone mineral equilibrium point with Ca ions. Modulus measurements were repeated at 6 and 10 days. The oquilibrium Ca ion con.centration for bone specimens was found to be 57.5 mgl - •. The modulus of bone specimens soaked in normal saline significantly diminished 2.4%, whereas the modulus of those soaked in calcium-buffered saline did not change significantly

    Feature integration in natural language concepts

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    Two experiments measured the joint influence of three key sets of semantic features on the frequency with which artifacts (Experiment 1) or plants and creatures (Experiment 2) were categorized in familiar categories. For artifacts, current function outweighed both originally intended function and current appearance. For biological kinds, appearance and behavior, an inner biological function, and appearance and behavior of offspring all had similarly strong effects on categorization. The data were analyzed to determine whether an independent cue model or an interactive model best accounted for how the effects of the three feature sets combined. Feature integration was found to be additive for artifacts but interactive for biological kinds. In keeping with this, membership in contrasting artifact categories tended to be superadditive, indicating overlapping categories, whereas for biological kinds, it was subadditive, indicating conceptual gaps between categories. It is argued that the results underline a key domain difference between artifact and biological concepts

    Modern microwave methods in solid state inorganic materials chemistry: from fundamentals to manufacturing

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    Critical Review of Theoretical Models for Anomalous Effects (Cold Fusion) in Deuterated Metals

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    We briefly summarize the reported anomalous effects in deuterated metals at ambient temperature, commonly known as "Cold Fusion" (CF), with an emphasis on important experiments as well as the theoretical basis for the opposition to interpreting them as cold fusion. Then we critically examine more than 25 theoretical models for CF, including unusual nuclear and exotic chemical hypotheses. We conclude that they do not explain the data.Comment: 51 pages, 4 Figure

    New Perspectives on the Aging Lexicon

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    The field of cognitive aging has seen considerable advances in describing the linguistic and semantic changes that happen during the adult life span to uncover the structure of the mental lexicon (i.e., the mental repository of lexical and conceptual representations). Nevertheless, there is still debate concerning the sources of these changes, including the role of environmental exposure and several cognitive mechanisms associated with learning, representation, and retrieval of information. We review the current status of research in this field and outline a framework that promises to assess the contribution of both ecological and psychological aspects to the aging lexicon

    Exemplar by feature applicability matrices and other Dutch normative data for semantic concepts

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