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    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

    Distortion product otoacoustic emissions in Mènière disease

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    Distortion product otoacoustic emissions (DPOAEs) are an objective, non-invasive measure for evaluating outer hair cell (OHC) activity. In this study DPOAEs were measured in 70 patients affected by Meniere's disease (MD). In addition 58 out of 70 patients performed both an audiometric threshold evaluation pre- and postglycerol administration (i.e. glycerol test) and DPOAEs pre- and post-osmotic drug assumption. The purpose of this combined form of testing was to explore the effects of glycerol on the active non-linear mechanisms of the cochlea. More than 60% of the ears with MD emitted DPOAEs despite the presence of an average hearing threshold level above 40 dB (HTL). Changes in the DPOAE baseline measures were observed in 32.4% of cases after glycerol administration. Patients were divided in four groups according to the different pattern of DPOAEs shown after the glycerol test. In particular, three-quarters of cases showed a significant increase in DPOAE amplitude, one-quarter of patients, who initially did not express DPOAEs, eventually did after intake of the osmotic agent, while no decreased DPOAEs were observed in these series. The different expressions of DPOAEs should be associated with the evolutive phases of MD. In addiction, elucidation of the relationship between DPOAEs and the stages of MD was an outcome of this test
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