Recently biologists have been interested in a tide-associated periodic behavior displayed by the diatom Hantzschia virgata, a microscopic golden-brown alga that inhabits that portion of a shoreline washed by tides (the intertidal zone).Diatoms of this species, sometimes called "commuter" diatoms, remain burrowed in the sand during high tide, and emerge on the sand surface during the daytime low tide. Just before the sand is inundated by the rising tide, the diatoms burrow again. Some scientists hypothesize that commuter diatoms know that it is low tide because they sense an environmental change, such as an alteration in temperature or a change in pressure caused by tidal movement. However, when diatoms are observed under constant conditions in a laboratory, they still display periodic behavior, continuing to burrow on schedule for several weeks. This indicates that commuter diatoms, rather than relying on environmental cues to keep time, possess an internal pacemaker or biological clock that enables them to anticipate periodic changes in the environment. A commuter diatom has an unusually accurate biological clock, a consequence of the unrelenting environmental pressures to which it is subjected; any diatoms that do not burrow before the tide arrives are washed away.

    This is not to suggest that the period of this biological clock is immutably fixed. Biologists have concluded that even though a diatom does not rely on the environment to keep time, environmental factors—including changes in the tide's hydrostatic pressure, salinity, mechanical agitation, and temperature—can alter the period of its biological clock according to changes in the tidal cycle. In short, the relation between an organism's biological clock and its environment is similar to that between a wristwatch and its owner: the owner cannot make the watch run faster or slower, but can reset the hands. However, this relation is complicated in intertidal dwellers such as commuter diatoms by the fact that these organisms areexposed to the solar-day cycle as well as to the tidal cycle, and sometimes display both solar-day and tidal periods in a single behavior. Commuter diatoms, for example, emerge only during those low tides that occur during the day.

    Frazier and Mosteller assert that medical research could be improved by a move toward larger, simpler clinical trials of medical treatments. Currently, researchers collect far more background information on patients than is strictly required for their trials—substantially more than hospitals collect-thereby escalating costs of data collection, storage, and analysis. Although limiting information collection could increase the risk that researchers will overlook facts relevant to a study, Frazier and Mosteller contend that such risk, never entirely eliminable from research, would still be small in most studies. Only in research on entirely new treatments are new and unexpected variables likely to arise.

    Frazier and Mosteller propose not only that researchers limit data collection on individual patients but also that researchers enroll more patients in clinical trials, thereby obtaining a more representative sample of the total population with the disease under study. Often researchers restrict study participation to patients who have no ailments besides those being studied. A treatment judged successful under these ideal conditions can then be evaluated under normal conditions. Broadening the range of trial participants, Frazier and Mosteller suggest, would enable researchers to evaluate a treatment's efficacy for diverse patients under various conditions and to evaluate its effectiveness for different patient subgroups. For example, the value of a treatment for a progressive disease may vary according to a patient's stage of disease. Patients' ages may also affect a treatment's efficacy.

(The following was excerpted from material written in 1988.)

    For over a decade the most common policy advice given to developing countries by international development institutions has been to copy the export-oriented path of the newly industrializing countries, the celebrated NIC's. These economies—Brazil, Hong Kong, Mexico, Singapore, South Korea, and Taiwanburst into the world manufacturing market in the late 1960's and the 1970's; by 1978 these six economies, along with India, enjoyed unequaled growth rates for gross national product and for exports, with exports accounting for 70 percent of the developing world's manufactured exports. It was, therefore, not surprising that dozens of other countries attempted to follow their model, yet no countries—with the possible exceptions of Malaysia and Thailand—have even approached their success. In "No More NIC's," Robin Broad and John Cavanagh search for the reasons behind these failures, identifying far-reaching changes in the global economy—from synthetic substitutes for commodity exports to unsustainable levels of foreign debt—as responsible for a glut economy offering little room for new entrants. Despite these changes, the authors maintain, the World Bank and the International Monetary Fund—the foremost international development institutions—have ontinued to promote the NIC path as the way for heavily indebted developing countries to proceed. And yet the futility of this approach should, according to the authors, be all too apparent so many years into a period of reduced growth in world markets.