Richard Trueswell's Contribution to Collection Evaluation and Management: A Review

A Review of: Trueswell, R. L. (1969). Some behavioral patterns of library users: The 80/20 rule. Wilson Library Bulletin, 43(5), 458-461. Abstract Objective – To demonstrate the relationship between library circulation and the percent of a library's holdings satisfying circulation. Design – Retrospective cohort study of library circulation data. Setting – Cambridge and Northampton, Massachusetts, United States of America. Subjects – The users of the monographic holdings of the Air Force Cambridge Research Laboratory Library and the Forbes Public Library. Methods – Trueswell compiled circulation data from the Air Force Cambridge Research Laboratory Library over a period of 5 years, ostensibly from 1964-1969. Additionally, he gathered circulation data from Forbes Public Library. Trueswell compared each respective collection of data against the entire holdings of each library, after which he converted each measure to a percentage of the whole. Main Result – Based on the collected data, Trueswell found that the percentages of both libraries’ holdings that satisfy circulation follow a power law distribution. He compared this with a previous study measuring journal circulation at a Health Sciences Library that exhibited the same pattern. He stated that these similar distributions demonstrated the "80/20 Rule." The distribution is such that any given percent of circulation will provide the percent of a library’s circulating holdings necessary to satisfy it. Additionally, Trueswell found that 75 percent of current circulation had circulated at least once within the preceding year. Conclusion – The findings have implications for core collection development, purchasing multiple copies of a given title, determining the optimal size of a library's collection, and weeding. Trueswell also submits the idea of developing regional interlibrary loan centers for books that do not circulate often, as a cost saving measure for most libraries.

Development and Experimental Study of Phantoms for Mapping Skin Chromophores

Skin chromophore phantoms are widely used for better understanding of the light interaction with tissue and for calibration of skin diagnostic imaging techniques. In this work, different phantoms were examined and compared in order to find biologically equivalent substances that are the most promising for this purpose. For mimicking the skin medium and layered structure, a fibrin matrix with epidermal and dermal cell inclusion was used. Synthesized bilirubin, red blood cells and nigrosin were taken as absorbers. For spectral analysis of the developed phantoms a computer-aided multispectral imaging system Nuance 2.4 (Cambridge Research & Instrumentation, Inc., USA) was used. In this study, skin phantoms were created using such substances as bilirubin, melanin, haemoglobin and nigrosin