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Scientometrics
Authors: Jacob B. Slyder, Beth R. Stein, Brent S. Sams, David M. Walker, B. Jacob Beale, Jeffrey J. Feldhaus, and Carolyn A. Copenheaver

forestry departments across ten major public universities in the United States; (2) within this same population compare self-citation practices and (3) compare the patterns of citation frequency that a paper received over its post-publication lifespan. Our

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Abstract  

Studies on the life-span of past scientists according to data of theChronicle of Major Events of Natural Sciences have found that the age of optimum peak value of scientific discovery is about half the peak value of their life-span. Achievements of those scientists who made a name before 25 years old are 44 percent more than average and their life efficiency is 1.7 times that of the average. Therefore it is an effective measure to train prococious scientists for a nation in her strive to catch up with or surpass world level in science.

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The World Wide Web is growing at an enormous speed, and has become an indispensable source for information and research. New pages are constantly added, but there are additional processes as well: pages are moved or removed and/or their content changes. We report here the results of an eight year long project started in 1998, when multiple search engines were used to identify a set of pages containing the term informetrics. Data collection was repeated once a year for the last eight years (with the exception of 2000 and 2001) using both search engines and revisiting previously identified pages. The results show that the number of pages grew from 866 in 1998 to 28,914 in 2006 — a 33-fold growth. Besides the obvious growth of the topic on the Web, we observed both decay (pages disappearing from the Web) and modification. Even though most of the pages from 1998 either disappeared or ceased to contain the term informetrics, 165 pages (19.1%) still exist in 2006 and contain the search term. We followed the “fate” of these 165 pages: characterized the publishers, the contents and the changes that occurred the whole period. In recent years e-print servers and publishers’ sites became sources of large number of pages related to informetrics. Longitudinal studies following the evolution of a topic on the Web are very important, since they provide insights about content and the underlying Web processes.

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The time-course of average age of members of the Russian Academy of Sciences in the XVIII–XIX centuries was analyzed. A long-term trend of academician aging was found, with its extrapolation correctly predicting the average age of the recent academicians. Although the lifespan was increasing as well and its effect can statistically explain the most part (up to 80%) of variance in the average age, it was not the only cause. Furthermore, its effect might be indirect (i.e. the increasing average age was not simply due to a longer lifespan of elected members), since average membership span was slightly decreasing. At least a part of the trend was caused by a growth of competition for election since it was negatively correlaten with a contemporaneous number of members (at given lifespan and historical year). Comparison of three groups (full members, corresponding members and foreign members), differing in competition level, supports this suggestion. Besides the history of science, the results may be useful for dealing with the problem of growing age of the scientific establishment.

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). Archambault , E 2002 Methods for using patents in cross-country comparisons . Scientometrics 54 1 15 – 30 10.1023/A:1015654903218 . Bar-Ilan , J , Peritz , B 2009 The lifespan of

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.1177/1056492607305894 . Slyder , JB , Stein , BR , Sams , BS , Walker , DM , Beale , BJ , Feldhaus , JJ , Copenheaver , CA 2011 Citation pattern and lifespan: A comparison of discipline, institution and individual . Scientometrics 89 3 955 – 966 10.1007/s11192

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Scientometrics
Authors: Xingjian Liu, F. Benjamin Zhan, Song Hong, Beibei Niu, and Yaolin Liu

lifespan: A comparison of discipline, institution, and individual . Scientometrics 89 : 955 – 966 10.1007/s11192-011-0467-x . Taskin , Z . Contribution of Turkish scholars to earthquake literature: The

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Resources has proportionally more delayed papers than the other two areas. Because scientific literature in this area has a longer life-span, more papers are classified as delayed publications. On the other hand, Materials Science contains proportionally

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Abstract  

The aim of this paper is to model and study the age of the Web using a sample of about four million of web pages from the 16 European Research Area countries obtained during 2004 and 2005. Web page time-stamp (date when the web pages were created or last changed for last time), format and size in bytes data have been analysed. Several indicators are introduced to measure longitudinal aspects of the Web. Half-age is proposed as a measure of the age distribution because this is found to be exponential. “Web Update Index” and “Lifespan Index” are introduced to measure the changing rate of a small sample over time. Results show that the British Web space has the youngest Web pages while the Greek and Belgian ones have the oldest. The study also compared Web pages topics and found that Biology pages are more stable than Physics pages.

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