502 research outputs found

    Emerging Alternatives to the Impact Factor

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    Purpose: The authors document the proliferating range of alternatives to the impact factor that have arisen within the past five years, coincident with the increased prominence of open access publishing. Methodology/Approach: This paper offers an overview of the history of the impact factor as a measure for scholarly merit; a summary of frequent criticisms of the impact factor’s calculation and usage; and a framework for understanding some of the leading alternatives to the impact factor. Findings: This paper identifies five categories of alternatives to the impact factor: a. Measures that build upon the same data that informs the impact factor. b. Measures that refine impact factor data with “page rank” indices that weight electronic resources or Web sites through the number of resources that link to them. c. Measures of article downloads and other usage factors. d. Recommender systems, in which individual scholars rate the value of articles and a group’s evaluations pool together collectively. e. Ambitious measures that attempt to encompass the interactions and influence of all inputs in the scholarly communications system. Value of Paper: Librarians can utilize the measures described in this paper to support more robust collection development than is possible through reliance on the impact factor alone

    Emerging Alternatives to the Impact Factor

    Get PDF
    Purpose: The authors document the proliferating range of alternatives to the impact factor that have arisen within the past five years, coincident with the increased prominence of open access publishing. Methodology/Approach: This paper offers an overview of the history of the impact factor as a measure for scholarly merit; a summary of frequent criticisms of the impact factor’s calculation and usage; and a framework for understanding some of the leading alternatives to the impact factor. Findings: This paper identifies five categories of alternatives to the impact factor: a. Measures that build upon the same data that informs the impact factor. b. Measures that refine impact factor data with “page rank” indices that weight electronic resources or Web sites through the number of resources that link to them. c. Measures of article downloads and other usage factors. d. Recommender systems, in which individual scholars rate the value of articles and a group’s evaluations pool together collectively. e. Ambitious measures that attempt to encompass the interactions and influence of all inputs in the scholarly communications system. Value of Paper: Librarians can utilize the measures described in this paper to support more robust collection development than is possible through reliance on the impact factor alone

    A quantitative analysis of measures of quality in science

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    Condensing the work of any academic scientist into a one-dimensional measure of scientific quality is a difficult problem. Here, we employ Bayesian statistics to analyze several different measures of quality. Specifically, we determine each measure's ability to discriminate between scientific authors. Using scaling arguments, we demonstrate that the best of these measures require approximately 50 papers to draw conclusions regarding long term scientific performance with usefully small statistical uncertainties. Further, the approach described here permits the value-free (i.e., statistical) comparison of scientists working in distinct areas of science.Comment: 11 pages, 8 figures, 4 table

    Disease gradient of the anthracnose agent Apiognomonia quercina in a natural oak stand

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    Patterns of spore dispersal of the fungal pathogen Apiognomonia quercina and its anamorph Discula quercina were investigated over two consecutive growing seasons in a natural mixed stand of Quercus cerris and Q. pubescens trees located in a inland area of Tuscany, at an altitude of 400 m a.s.l. To measure spore dispersal, a transect was laid out in the stand to serve as an inoculum source. The rate of inoculum dispersal (conidia and ascospores) was quantifi ed by means of spore traps positioned at 10, 100, 500 and 1000 m from the southern end of the transect. The disease gradient was also assessed by determining the disease incidence on selected trees at the same distances from the transect. The amount of inoculum detected decreased steeply with the distance from the transect. Disease incidence was inversely correlated with the disease gradient, i.e. with the distance from the inoculum source, and it was much higher at the shorter distances. The level of spore dispersal was related to both the distance from the infection foci and the sporulation time. The experimental approach constituted a valid means for describing and understanding the dynamics of windborne diseases in forests
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