Atop the list of scientists are two names that have not yet been highlighted in  Science Watch: Kenji Kangawa and Masayasu Kojima, colleagues at the National Cardiovascular Center Research Institute in Osaka, Japan. Their six Hot Papers concern ghrelin, a peptide secreted in the stomach and involved in the release of growth hormone. The two authors and their colleagues at the Research Institute, along with a team from Miyazaki Medical College, Miyazaki, Japan, reported their discovery of the peptide in a report published in late 1999 (see M. Kojima, et al., Nature, 402[6762]:656-60, 9 December 1999, which surfaced in the Biology Top Ten last summer). In this report and five other Hot Papers published subsequently, Kangawa and Kojima and their colleagues examine the function of ghrelin (the team coined the name from ghre, the Indo-European root of the word “grow”) in the stomach of rats and humans. Researchers worldwide are currently evaluating ghrelin's role in the regulation of growth, feeding, and energy homeostasis.

The next two names on the list both appeared in last year's roundup: J. Craig Venter, who recently announced his resignation as president of Celera Genomics; and Eric S. Lander of the Whitehead Institute, who is interviewed in this issue. Not surprisingly, the 2001 human-genome reports from Science and Nature, on which the scientists appeared as respective first authors, emerged as the year's two most-cited reports—each scoring citation tallies at least four times as great as the highest same-year total previously recorded in these pages.

Another genome researcher, Masahira Hattori of the RIKEN Genomic Science Center, Sagamihara, Japan, fielded five Hot Papers over the last two years. A coauthor on 2001's chart-topping Nature human-genome paper, Hattori also contributed to papers reporting sequence data on chromosome 21 and on drug-resistant Staphylococcus aureus.

The rest of the author list belongs to space science, and to international collaborators on five highly cited papers from the balloon-borne MAXIMA-1 and BOOMERANG experiments, which measured the cosmic microwave background and extra-galactic radiation. Two of these reports rank among 2001's most cited (#13, #28), while the other three currently reside in the Physics Top Ten, at #3, #6, and #8 (see page 6).

In all, it was a very good year for the physical sciences, with magnesium diboride superconductors particularly hot, scoring five of the top ten places among the year's most-cited papers (#3, #4, #6, #7, #10) and four other spots besides (#12, #20, #30, #35).