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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

    Adequacy of screening cervical cytology among human immunodeficiency virus-seropositive women.

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    OBJECTIVE: To evaluate the adequacy of cytology in detecting cervical intraepithelial neoplasia (CIN) among human immunodeficiency virus (HIV)-seropositive women compared to controls. METHODS: A cross-sectional study was carried out evaluating 241 HIV-seropositive women and 991 controls (404 HIV seronegative and 587 of unknown HIV status) at risk for CIN attending a vaginitis clinic. All patients had a Pap smear and a standard colposcopic examination of the lower genital tract. Cervical biopsies were taken as indicated by colposcopy. Cytology and histology slides were read by a cytopathologist blinded to patients' serostatus. False-negative cytologic cases were reviewed by three independent cytopathologists to estimate sampling and screening error rates. Sensitivity, specificity, and false-negative rate of cytologic smears were compared between HIV seropositives and controls. We estimated the sampling and screening error rates among cases with false-negative cytology. RESULTS: Among seropositives, the sensitivity, specificity, and the false-negative smear rate for CIN were 73.4% (47/64), 97.1% (134/138), and 26.6% (17/64), respectively. The corresponding figures in controls were 83.8% (83/99), 99.04% (825/833), and 16.2% (16/99), respectively, and did not differ significantly from those of seropositives. The negative predictive value of cytology was lower among seropositives (134/151) than in controls (825/841, chi2 = 34.8, P < .001). The agreement between cytologic readings and combined colposcopy and histology was stronger among controls (kappa = 0.789, 95% CI 0.723 to 0.856) than among seropositives (kappa = 0. 593, 95% CI 0.475 to 0.712). Three independent cytopathologists were unable to detect atypical cells in 52.9% (9/17) of false-negative smears taken from seropositive women as opposed to 37.5% (6/16) of controls. CONCLUSIONS: The sensitivity, specificity, and false negative rate of screening cytology for CIN among HIV seropositive women are comparable with those in the general population. Since almost 50% of false-negative results could be attributed to sampling errors, more frequent cytological screening may prove to be beneficial to this high-risk group
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