On the relationship between citations of publication output and Hirsch index h of authors: conceptualization of tapered Hirsch index h T, circular citation area radius R and citation acceleration a

The nature of the empirical proportionality constant A in the relation L = Ah ² between total number of citations L of the publication output of an author and his/her Hirsch index h is analyzed using data of the publication output and citations for six scientists elected to the membership of the Royal Society in 2006 and 199 professors working in different institutions in Poland. The main problem with the h index of different authors calculated by using the above relation is that it underestimates the ranking of scientists publishing papers receiving very high citations and results in high values of A. It was found that the value of the Hirsch constant A for different scientists is associated with the discreteness of h and is related to the tapered Hirsch index h _T by A ^1/2 ≈ 1.21h _T. To overcome the drawback of a wide range of A associated with the discreteness of h for different authors, a simple index, the radius R of circular citation area, defined as R = (L/π)^1/2 ≈ h, is suggested. This circular citation area radius R is easy to calculate and improves the ranking of scientists publishing high-impact papers. Finally, after introducing the concept of citation acceleration a = L/t ² = π(R/t)² (t is publication duration of a scientist), some general features of citations of publication output of Polish professors are described in terms of their citability. Analysis of the data of Polish professors in terms of citation acceleration a shows that: (1) the citability of the papers of a majority of physics and chemistry professors is much higher than that of technical sciences professors, and (2) increasing fraction of conference papers as well as non-English papers and engagement in administrative functions of professors result in decreasing citability of their overall publication output.     

Use of bibliometric information to assist research policy making. A comparison of publication and citation profiles of Full and Associate Professors at a School of Chemistry in Uruguay

Summary Publication and citation profiles of Full and Associate Professors at the School of Chemistry of the Universidad de la República in Uruguay were investigated. The groups do not exhibit markedly different age averages. However, the average time since they started publishing, as well as other characteristics of their publication records, like productivity or citations, set them apart. From the point of view of both the number of papers per author and per year of activity, on one side, and of the number of citations per year of activity, on the other, the group of Full Professors has statistically significant larger averages than the Associate Professors. The impact of self-citations, multi-authorship and internationalization of the publications were analyzed within the two groups and shown to have no excessive or predictable influence on those parameters, except in the case of few (≤ 2) or many (>8) authors. It is suggested in this paper that these two indicators, number of papers per author per production year and number of citations per production year, combined in a plot allowing a bidimensional ranking of the individuals in the groups, may be used profitably as one of the components in the development of a policy toward promotion of Associate Professors. The analysis showed also that the quotient of citations received to number of papers published, even when derived from actual citation data of the scientists without involving the impact factors of the journals in which they publish, are not good parameters to use for that purpose, essentially because there is a reduction in the information content of the indicator with respect to those described before.     

The evaluation of university departments and their scientists: Some general considerations with reference to exemplary bibliometric publication and citation analyses for a Department of psychology

In reference to an exemplary bibliometric publication and citation analysis for a University Department of Psychology, some general conceptual and methodological considerations on the evaluation of university departments and their scientists are presented. Data refer to publication and citation-by-others analyses (PsycINFO, PSYNDEX, SSCI, and SCI) for 36 professorial and non-professorial scientists from the tenure staff of the department under study, as well as confidential interviews on self-and colleagues-perceptions with seven of the sample under study. The results point at (1) skewed (Pareto-) distributions of all bibliometric variables demanding nonparametrical statistical analyses, (2) three personally identical outliers which must be excluded from some statistical analyses, (3) rather low rank-order correlations of publication and citation frequencies having approximately 15% common variance, (4) only weak interdependences of bibliometric variables with age, occupational experience, gender, academic status, and engagement in basic versus applied research, (5) the empirical appropriateness and utility of a normative typological model for the evaluation of scientists’ research productivity and impact, which is based on cross-classifications with reference to the number of publications and the frequency of citations by other authors, and (6) low interrater reliabilities and validity of ad hoc evaluations within the departments’ staff. Conclusions refer to the utility of bibliometric data for external peer reviewing and for feedback within scientific departments, in order to make colleague-perceptions more reliable and valid.     

An overview of the history of Science of Science in China based on the use of bibliographic and citation data: a new method of analysis based on clustering with feature maximization and contrast graphs

In the first part of this paper, we shall discuss the historical context of Science of Science both in China and at world level. In the second part, we use the unsupervised combination of GNG clustering with feature maximization metrics and associated contrast graphs to present an analysis of the contents of selected academic journal papers in Science of Science in China and the construction of an overall map of the research topics’ structure during the last 40 years. Furthermore, we highlight how the topics have evolved through analysis of publication dates and also use author information to clarify the topics’ content. The results obtained have been reviewed and approved by 3 leading experts in this field and interestingly show that Chinese Science of Science has gradually become mature in the last 40 years, evolving from the general nature of the discipline itself to related disciplines and their potential interactions, from qualitative analysis to quantitative and visual analysis, and from general research on the social function of science to its more specific economic function and strategic function studies. Consequently, the proposed novel method can be used without supervision, parameters and help from any external knowledge to obtain very clear and precise insights about the development of a scientific domain. The output of the topic extraction part of the method (clustering?+?feature maximization) is finally compared with the output of the well-known LDA approach by experts in the domain which serves to highlight the very clear superiority of the proposed approach.

     

A comparison of drug-treated and untreated HCT-116 human colon adenocarcinoma cells using a 2-D liquid separation mapping method based upon chromatofocusing PI fractionation

A multidimensional chromatographic 2-D liquid-phase separation method has been developed for differential display of proteins from cell lysates and applied to a comparison of protein expression between Peninsularinone-treated and untreated HCT-116 human colon adenocarcinoma cells. The method involves fractionation according to pI using chromatofocusing with analytical columns in the first dimension followed by separation of the proteins in each pI fraction using nonporous reversed-phase HPLC. A 2-D map of the protein content of each cell line based upon pI versus hydrophobicity as detected by UV absorption was generated and a differential display map indicating the presence of up- or downregulated proteins displayed using ProteoVue and DeltaVue software. Using this method, > 1000 protein bands could be detected in 0.2 pH fractions over a pH range of 4-7. In addition, the liquid eluent from the separation was directed on-line into an electrospray TOF-MS to obtain an accurate molecular weight of the intact proteins. An accurate molecular weight together with the peptide map was used to obtain protein identification using database searching. The method has been shown to have high reproducibility for quantitative differential display analysis of interlysate comparisons, generation of accurate protein identifications, and ease of data interpretation. It has been used herein to identify proteins that change as a function of drug treatment. The relative simplicity of the current procedure and the potential for full automation will make this technique an essential tool in future proteomic studies.     

The use of electronic pharmacy data to investigate prescribed medications and fatal motor vehicle crashes in a military population, 2002-2006

The authors examined the association between prescribed medications and fatal motor vehicle crashes (MVCs) in an active duty military population between 2002 and 2006. Using a case-control design, MVC deaths were ascertained using a military mortality registry, and an integrated health system database provided information on health system eligibility, pharmacy transactions, and medical encounters. Cases and controls were matched on comparable observation time outside periods of deployment. Among selected categories, only one, antidepressant medications, was an independent predictor of fatal MVC (odds ratio, 3.19; 95% confidence interval, 1.01-10.07). Male gender, Black race, enlisted rank, service branch (Navy and Marine Corps), and selected co-morbidities were also independent predictors. Unexpectedly, the odds of younger age quartiles (<27 years) and history of deployment were reduced for MVC cases. Although results need to be considered in the context of data limitations, the association between prescribed antidepressants and fatal MVC may reflect unmeasured co-morbidities, such as combined effects of prescribed and over-the-counter medications and/or alcohol or other substance abuse. Younger individuals, representing new military accessions in training or returning from deployment with serious injuries, may have fewer opportunities to operate vehicles, or targeted efforts to reduce MVC following deployment may be showing a positive effect.     

<Emphasis Type=Italic>hg</Emphasis>-index: a new index to characterize the scientific output of researchers based on the <Emphasis Type=Italic>h</Emphasis>- and <Emphasis Type=Italic>g</Emphasis>-indices

To be able to measure the scientific output of researchers is an increasingly important task to support research assessment decisions. To do so, we can find several different measures and indices in the literature. Recently, the h-index, introduced by Hirsch in 2005, has got a lot of attention from the scientific community for its good properties to measure the scientific production of researchers. Additionally, several different indicators, for example, the g-index, have been developed to try to improve the possible drawbacks of the h-index. In this paper we present a new index, called hg-index, to characterize the scientific output of researchers which is based on both h-index and g-index to try to keep the advantages of both measures as well as to minimize their disadvantages.     

The structure refinement of boehmite (-A100H) and the study of its structural variability based on Guinier-Hägg powder data

The extent of structural variability of boehmite has been studied by the comparison of the structure parameters of a synthetic and a natural mineral sample. Profile-fitting refinement based on Guinier-Hägg type powder data was used to determine the actual structures. It is also concluded that the small structural differences found do not interfere with the established practice of taking boehmite as reference in X-ray diffractometric quantitative phase analysis of minerals.