117,327 research outputs found

    Late normalisation of uterine artery velocimetry in high risk pregnancy

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    OBJECTIVE: To test whether late normalisation of abnormal uterine velocimetry is a favourable prognostic factor in high risk pregnancies. STUDY DESIGN: Uterine artery colour Doppler velocimetry was performed at 24, 28-30 and 32-34 weeks in 282 high risk pregnancies treated with low dose aspirin. RESULTS: 88 patients had abnormal waveforms at 24 weeks and 77 delivered after the second assessment at 28 weeks. Of these, 38 (49%) had a normalisation of Doppler indices by 34 weeks. Compared with the persistently abnormal Doppler group, these patients delivered fewer small for gestational age babies (5/38 versus 26/39; p=0.0001) and had less gestational hypertension without proteinuria (3/38 versus 15/39; p=0.004). No patients with preeclampsia or other severe complications of pregnancy were observed in the normalised group. CONCLUSIONS: Although abnormal uterine artery velocimetry at 24 weeks is predictive of adverse pregnancy outcome, nearly half have late normalisation of the Doppler indices and a better perinatal outcome. Persistently abnormal waveforms are related to the worst pregnancy outcome

    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

    Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?

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    In this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association

    Appropriate Similarity Measures for Author Cocitation Analysis

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    We 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

    Letter from unknown writer to Jesse L. Boyce

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    Letter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County

    Effect of betamethasone on computerized cardiotocographic parameters in preterm growth-restricted fetuses with and without cerebral vasodilation.

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    OBJECTIVE: To verify the effects of maternal corticosteroid administration on fetal behavior and heart rate variation using computerized cardiotocography (cCTG) in a selected group of growth retarded fetuses. STUDY DESIGN: Fifty singleton pregnancies complicated by fetal growth restriction were enrolled in the study before 34 weeks of gestation. All of them received two intramuscular injections of 12 mg of betamethasone 24 h apart. Fetal heart rate was recorded by cCTG before the first injection, and every 24 h for the 3 days following the end of the treatment. After Doppler evaluation of cerebral circulation, fetuses were divided into a group with and a group without signs of cerebral vasodilation. Basal heart rate, short- and long-term variation, percentage of time spent in high variability, fetal movements and percentage of small accelerations were evaluated. RESULTS: Basal fetal heart rate did not show significant changes. Short-term variation and percentage of time spent in high variability significantly decreased in fetuses with but not in fetuses without vasodilation. Long-term variation and fetal movements significantly decreased in both groups. CONCLUSIONS: Maternal administration of betamethasone in growth-retarded fetuses with cerebral vasodilation is associated with significant but transitory modifications of fetal heart rate variation

    Dispelling the Myths Behind First-author Citation Counts

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    We conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more sophisticated methods
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