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accumulated over the six decades following each author's first publication and shows that for each author the h -index increases approximately linearly so that the a -index is approximately constant, giving the age independent index promised in the title
distribution over time is shown in Fig. 1 . There have been two approaches to study the citation distribution. The first considers papers cited by a publication during a particular year and then analyzes retrospectively the distribution of their ages. This
Abstract
The analysis of the references contained in documents published by developed and underdeveloped countries indicate that developed and underdeveloped countries age the literature of 
international
areas of science in a similar pattern; underdeveloped countries age the literature reflecting local problems slower than developed countries age the same literature, and the communication patterns among Regions follow a center-periphery model.
Abstract
Analyses the age of references cited in source papers of the theoretical population genetics speciality at different phases of its development. Discusses the characteristics of specialities in terms of obsolescence measures such as half-life and immediacy index. Explores the applicability of different theoretical probability functions in the age densities of references cited. Concludes that age of references cited is best modelled according to lognormal distribution.
Abstract
This paper examines the common contentions that the collective aging of tenured academic staff has negative effects on research performance of universities due to (a) negative effects of aging in itself, and (b) to a lack of newcomers who could revitalise the research. Data on academic staff and research at Norwegian universities over two decades have been used to examine these contentions. While older staff published less than their younger colleagues two decades ago, no differences in productivity are found today. Furthermore, during this period, a large increase in the number of post-doctoral fellows and PhD students has taken place, compensating for the aging of tenured staff.
Abstract
This study analyzes the age profile of scientific employees and its relation to personnel costs and scientific productivity within eight faculties at the University of Vienna. The age demography can overall be divided into two main categories: Category one faculties represent an increased number of younger aged researchers (Catholic-, Protestant Theology, Law, Economics, Information Sciences, and Medicine), category two faculties show an increased number of older aged researchers (Social Sciences, Humanities, and Science). In addition, it can be demonstrated that the personnel costs for full professors are higher within four faculties (Catholic-, Protestant Theology, Law, and Economics and Information Sciences). Inevitably, this leads to savings for habilitated and non- habilitated researchers at these faculties. The faculty of Medicine represents a well-balanced use of personnel costs. Three faculties (Social Sciences, Humanities, and Sciences) have to pay dramatically more for their older aged habilitated and non-habilitated personnel. For the entire university and two faculties, Medicine and Humanities, a positive and significant relationship between age and the average weekly teaching performance is shown. This study suggests that institutions with a high percentage of older researchers, mainly in the categories of habilitated and non- habilitated personnel, must change their policy to become more flexible and attractive for new talented young people. Due to the fact, that this cannot only be realized through the introduction of new laws, each faculty must establish a scientific plan combined with reorganizations of the personnel structure and personnel costs.
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.
Abstract
To compare citation history and contextual 
importance
, eleven highly cited articles, 4 slowly aging (Type 1) and 7 quickly aging (Type 2), were ranked using an aggregate citation context measure, the Mean Utility Index. Based on citations in late (PY 6 & 7) source articles, methods papers consistently ranked higher than papers cited for research results and theoretical implications, and Type 1 methods papers ranked above all Type 2 papers. A Type 1 paper representing an important theoretical concept could not be distinguished from Type 2 papers using citation context alone.
Abstract
A statistical analysis is made of two data sets and it is found that the distribution of major scientific and technological achievements in terms of the age of those achievement makers is Weibull distribution. Pearson'sx 2 test results are satisfactory. This finding holds for different centuries, different nations and different disciplines.
Abstract
The productivity factor is very important at the mathematical simulation of scientific community evolution. In Ref. 1 the productivity index has been incorporated into the model exogenously to formulate the criterion of dynamic optimization of the scientific community age structure. In this paper we are going to include the productivity (as well as the age) in the individual state space and to derive the main dynamic equation which takes into account the stochastic fluctuations of scientific community members' productivity and some modifications of the Fokker-Planck equation. An approximation method for the evolution model is suggested with the aid of which the computational experiment is carried out. The discussion of experimental results and possible ways for improvement and extension of model are presented.
