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SUMMARYThis is the first of a series of papers on the Genesis distributed-memory benchmarks, which were developed under the European ESPRIT research program. The benchmarks provide a standard reference Fortran77 uniprocessor version, a distributed memory MIMD version, and in some cascs a Fortran90 vcrsion suitable for SIMD computers. The problems selected all have a scientific origin (mostly from physics or theoretical chemistry), and range from synthetic code fragments dcsigncd to mcasurc the basic hardware properties of the computer (especially communication and synchronisation overheads), through commonly used library submutines, to full application codes. This first paper defines the methodology to be used to analyse the benchmark results, and gives an example of a fully analysed application benchmark from General Relativity (CR1). First, suitable absolute performance metrics are carefully defined, then thc pcrformance analysis treats the execution time and absolute pcrformance as functions of at least two variables, namely the problem size and the number of proecssors. The theoretical predictions are compared with, or fitted to, the measured results, and then used to predict (with due caution) how the performance might scale for larger problems and more processors than were actually available during the benchmarking. Benchmark measurements are given primarily for the Geman SUPRENUM computer, but also for the IBM 30835, Convcx C210 and a Parsys Supernode with 32 T800-20 transputers.

The migration of researchers across geographic borders, or "brain drain" as it is commonly called, remains an important issue for governments around the world as loss or gain of highly qualified personnel in research can have substantial social, economic and political consequences. In the present study we seek to examine the forces that drive international professional migration of stem cell (SC) researchers, for which variation of SC policy in different jurisdictions has previously been implicated as a driving force. Structured interviews were carried out with a purposive sample of SC researchers in the professoriate who had made international moves after postdoctoral work between the years 2001-2014, or were actively anticipating a future move. Participants were asked to rank motivators of international movement on a 5-point Likert scale and prompted to elaborate on their answers. The results suggest that career considerations, availability of research funding, and personal considerations are of high importance to the participants when considering an international move, while the permissiveness or restrictiveness SC research policy is of comparably lower importance. Participants also expressed that international movements are beneficial to scientific careers overall. The findings have important implications for policy and strategies to attract and retain members of the SC research community.

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