104,905 research outputs found
Deep time foraminifera Mg/Ca paleothermometry: nonlinear correction for secular change in seawater Mg/Ca
No full text[1] The Mg/Ca ratio of foraminifera tests is increasingly being utilized as a paleotemperature proxy. Deep time (pre-Pleistocene) Mg/Ca paleothermometry is complicated by the fact that the Mg/Ca ratio of seawater (Mg/Casw) has undergone considerable secular variation over the Cenozoic. Previous studies have corrected for this by assuming an invariant Mg distribution coefficient (DMg) with Mg/Casw. More recent laboratory culturing has shown that this is not the case, demonstrating that a power relationship best describes the variation in test Mg/Ca (Mg/Catest) with Mg/Casw. Therefore, previous corrections are likely to have led to inaccurate temperature reconstructions. Here, we show how the systematics of such a correction should be applied and demonstrate why this provides good evidence that the Mg/Ca ratio of Paleogene seawater was lower than previously implied by foraminiferal constraints, in agreement with the majority of the proxy Mg/Casw evidence. We also demonstrate how it is indirectly possible to constrain the value of H, the power component of a Mg/Catest–Mg/Casw calibration, potentially enabling the appropriate correction of results derived from species where this relationship has not been calibrated. However, this technique should not be treated as a substitute for culturing. The previous erroneous assumptions regarding both (1) the relationship between Mg/Catest and Mg/Caswand (2) the Mg/Ca ratio of seawater at a given time in the past may counteract each other to differing extents. As a result, previous absolute pre-Pleistocene paleotemperature estimates derived from Mg/Ca ratios in foraminifera should be treated with caution, although relative temperature changes over short (<1 Ma timescales) are likely to be reliable
High Resolution Transmission Electron Microscopy to Study Very Thin Crystalline Layers Buried at an Amorphous-crystalline Interface
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Listrognathus mactator (Thunberg, 1824) (Hymenoptera: Ichneumonidae) A new recorded parasitoid of Cimbex quadrimaculatus (O. F. Mller, 1766) (Hymenoptera: Cimbicidae) in Turkey
No full textListrognathus mactator (Thunberg, 1824) (Hymenoptera: Ichneumonidae) was determined as a larva-pupa parasitoid of the almond pest, Cimbex quadrimaculatus (O. F. Mller, 1766) (Hymenoptera: Cimbicidae). The parasitoid is also recorded from Turkey for the first time
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Transmission Electron Microscopy Studies of the Microstructure of Si Layers Grown on GaAs(001) under an Excess As or Al Flux
No full textThe SAVE approach to component-based development of vehicular systems
No full textThe component-based strategy aims at managing complexity, shortening time-to-market, and reducing maintenance requirements by
building systems with existing components. The full potential of this strategy has not yet been demonstrated for embedded software,
mainly because of specific requirements in the domain, e.g., those related to timing, dependability, and resource consumption.
We present SaveCCT – a component technology intended for vehicular systems, show the applicability of SaveCCT in the engineering
process, and demonstrate its suitability for vehicular systems in an industrial case-study. Our experiments indicate that SaveCCT provides
appropriate expressiveness, resource efficiency, analysis and verification support for component-based development of vehicular
software
High-pressure optical spectroscopy and X-ray diffraction studies on synthetic cobalt aluminum silicate garnet
No full textAppropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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