1,721,010 research outputs found
Statistical modeling of gas-permeability spatial variability along a limestone core
No full textA set of more than 200 gas-permeability data is collected on centimeter-scale plugs drilled in a regular pattern along a core of Majorca limestone to test at the laboratory scale a recent model for the statistical characterization of spatial heterogeneity. Data are interpreted as samples of a generalized sub-Gaussian (GSG) random field. The latter results from the subordination of a spatially-correlated Gaussian field by a statistically-independent random field, which we take as log-normal in this application. The GSG model we analyze has been shown to be consistent with non-Gaussian and statistical scaling features that are frequently exhibited by several environmental variables, including hydrological properties. Key objectives of the current study are: (i) to provide a high-quality dataset from which one can assess statistical scaling features displayed by the data and their spatial increments; and (ii) to test the ability of the GSG model to characterize the observed behavior. We apply a statistical inference method to estimate the parameters of the GSG model on the basis of the available data. We then take advantage of formal model-identification criteria to consider the relative skills of diverse variogram models associated with the underlying Gaussian field to interpret the observed behavior of the dataset. Our results corroborate the effectiveness of the GSG modeling framework to characterize the documented aspects of statistical scaling
Acrylic microspheres as drug-delivery systems: synthesis through in situ microemulsion photoinduced polymerization and characterization
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
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