we haven't had one in 55,000 years. We must be overdue.' "

In neighboring Nevada, the U.S. gov­ernment is proposing to build a nuclear waste dump in the Yucca Mountains. Suitability requirements for the dump are strict: Two or more nearby earth­quakes during the past 500,000 years ren­der a site unsafe because they suggest the possibility of future seismic activity.

In the many studies of the nearby Cra­ter Flat area over the past decade, scien­tists have suspected that at least one like­ly seismic event has occurred in the past 500,000 years. The area is home to sever­al cinder cones, including the relatively young Lathrop Wells cone, which is be­tween 80,000 and 140,000 years old. Be­cause volcanic ash has been found in ground fractures in the area, scientists believe the seismic event occurred si­multaneously with a volcanic eruption.

A new method for dating volcanic ash has allowed Marek Zreda, assistant pro­fessor of hydrology at the University of Arizona, Tucson, to discover that a sec­ond seismic event may have occurred in the region in the past 500,000 years. Zreda and colleagues measured the ^Cl levels in two ash samples taken from near the surface of a fracture. The samples ap­peared to contain ash of two different ages: 80,000 years and 435,000 years.

The younger ash is the same age as the ash from the Lathrop Wells cone, corresponding to a simultaneous volca­nic/seismic event. The older ash's age is not similar to any of the other cones in the area, Zreda says. But the chemical composition of the old ash is similar to the younger ash, and so probably came from an earlier eruption of the Lathrop Wells site, bringing the number of seismic events in the past 500,000 years to two— too many for a nuclear waste dump.

In another application of mass spec­trometry, J. Warren Beck and George S. Burr, research scientists at the University of Arizona's physics department, are us­ing the technique to study ocean condi­tions recorded in the skeletons of band­ed corals.

These corals, which annually add to their skeletons, leave a physical record of their growth like a tree ring, providing evidence of ocean salinity, biological ac­tivity, and carbon dioxide exchange. An especially important record contained in coral skeletons is that of sea surface tem­perature, which is controlled by ocean circulation, including the abnormally warm water masses known as El Nino.

Αήζοηα scientists use mass spectrometry to determine the age of volcanic ash samples

collected from a ground fracture (right) near the Lathrop Wells cinder cone (above).

Beck and colleagues studied a species of coral that can grow for up to 1,000 years. The scientists measured variations of both 14C levels and the ratio of stron­tium to calcium in the most recent 20 years of coral skeleton layers. The Sr/Ca ratio is known to be dependent on sea surface temperature. With the measure­ments, Beck and colleagues were able to confirm El Nino events that occurred over the period.

While fluctuation of Sr/Ca ratios is well understood, the scientists aren't yet sure what causes 14C levels to vary.

"But we know it's related to El Nino," Burr says. And now, he adds, research­ers can use the corals to peer back over the last 1,000 years.

"The potential for this [research] is that we may be able to track El Nino episodes before historical records were available," Burr says.

Elizabeth Wilson

Stronger links between chemistry, math needed A message heard repeatedly at the American Chemical Society meeting in Anaheim, Calif., was that, as federal support for chemistry (and other scienc­es) declines in the coming years, chemis­try needs to forge productive links with other disciplines, In an era of pinched budgets—and no one seems to doubt that science budgets will be pinched, maybe tightly, over the next several years—mulridisciplinary research pro­posals are likely to have an edge.

It was fitting, then, that a new report advocating stronger ties between two disciplines—chemistry and mathemat­ics—not usually linked with each other was unveiled at a session in Anaheim. Frank H. Stillinger, a theoretical chem­ist at AT&T Bell Labs, Murray Hill, N.J., discussed the National Research Council's report, "Mathematical Chal­lenges from Theoretical/Computation­al Chemistry," at a session sponsored by the Division of Physical Chemistry.

Stillinger chaired the committee of 10 chemists and four mathematicians who prepared the NRC report. In Anaheim, Stillinger said that the "atmosphere ap­

pears to be right for fostering collabora­tions" among chemists and mathemati­cians. However, he added, "many dis­tinctive and quite troubling barriers" to such collaboration exist.

Stillinger said the committee decided early on that there exists a "seamless continuum between theoretical and computational chemistry," and that the report would address the mathematical challenges posed by "theoretical/ computational chemistry." He pointed out that numerous "success stories"— including the statistical prediction of drug and agricultural chemical potency and distance geometry applied to pro­tein folding, ligand docking, and similar interactions—illustrate the potential for productive collaborations between chem­istry and mathematics.

Nevertheless, cultural differences be­tween the mathematics and chemistry communities—involving language, train­ing, aesthetics, and research style—act as barriers to collaboration, Stillinger said. Mathematicians and chemists are largely unaware of the most exciting recent ad­vances in each others' fields. And mech-

MAY 1,1995 C&EN 55

inese corals, wnich annually add to their skeletons, leave a physical record of

SOFTWARE/DATABASE UPDATE

anisms for professional recognition— ranging from tenure decisions to prizes and awards—are not geared to recog­nize interdisciplinary research advances.

The report makes a number of recom­mendations to improve the ties between mathematics and chemistry. Starting at the undergraduate level, math and chemistry departments should encour­age students to meld the two fields in their studies. Departments should en­courage graduate degrees that involve dual chemistry and mathematics men­toring. And chemistry and mathematics department faculty should establish mechanisms such as research seminars or colloquia for regular interactions.

Additionally, the report recommends that "mathematics and chemistry de­partments encourage and value individ­ual and collaborative research that is at the interface of the two disciplines. Such work has the potential for significant in­tellectual impact on computational chemistry, and hence on the future evo­lution of chemical research and its appli­cations to problems of importance to our society/'

Professional societies such as ACS, the American Mathematical Society (AMS), and the Society for Industrial & Applied Mathematics (SIAM) also can play a role in fostering better contacts between the two disciplines, Stillinger said. Seminar or colloquium talks and panel discussions at society national meetings, for example, would intro­duce chemists and mathematicians to frontier research in the two disciplines. The NRC report points out that prom­ising moves in this direction already are occurring and cites recent AMS ses­sions on mathematics and molecular biology and SIAM sessions on chemis­try problems and optimization.

The committee also recommended that professional societies study the pos­sibility of establishing awards and named lectureships for work at the mathematics-chemistry interface. "High-level public recognition by peers would be a major step toward breaking down interdisciplinary barriers/' it states.

In keeping with the general percep­tion of tight research budgets to come, Stillinger pointed out that the committee "did not recommend more money." Im­proved collaborations between chemis­try and mathematics will have to be ac­complished within the limits of the con­strained budgets currently anticipated.

Rudy Baum

• Gaussian 94 (Scientific Computing Associates, price available from com­pany, circle 301) is the latest version of the Gaussian series of electronic structure programs and the first to support parallel execution. It runs on UNIX workstation clusters and on multiprocessor systems such as SGI PowerChallenge and IBM SP2 com­puters. Gaussian 94 enables larger molecular systems to be studied. New features include prediction of NMR spectra, improved solvation models, and higher efficiency geome­try optimizations.

• Dry Add (Oxford Materials, pur­chase or lease prices available from company, circle 302) is a program for modeling polymerization and cross-linking. The software makes it possible for researchers working on paints, coatings, adhesives, and nov­el polymers to develop new materi­als and formulations more quickly. The program is based on a Monte Carlo simulation of a reaction pot and was developed by industrial scientists from Glidden Co. and ICI Paints. It runs on IBM PCs and Sili­con Graphics workstations.

• Turbochrom Professional (Per-kin-Elmer, pricing available from company, circle 303) is a Windows program for chromatography data handling. For multiple-user, multi­ple-channel chromatography labs, the software provides system securi­ty, user configurability, client-server network interactions, and an audit log of all software changes. The pro­gram also meets good laboratory practices and good manufacturing practices requirements.

• Amber V4.1 (Oxford Molecular Group, pricing available from com­pany, circle 304) is a molecular me­chanics system for UNIX worksta­tions and larger computers. The package, including energy minimi­zation, molecular dynamics, and NMR structure refinement pro­grams, is used for studies of biolog­ical molecules and for drug discov­ery applications. Enhancements in the new version include an im­proved free-energy module (Gibbs), a faster and more powerful molecu­lar dynamics and NMR fitting pro­

gram (Sander), and a new molecular dynamics and free-energy perturba­tion program (Spasms).

M Graphic (Scientific Endeavors, $465 to $495, circle 305) is a high-res­olution graphing and plotting pro­gram for scientists and engineers. It enables users to produce graphics and plots for inclusion in their own programs, desktop publishing pack­ages, or scientific publications.

M CARD (Westing Software, $495, circle 306), the Computer Aided Re­search & Development program, is a Windows package for the design of research, development, and engi­neering experiments. CARD helps minimize the number of experi­ments needed to optimize products or processes. It handles multiple constraints and mixture systems. The program also includes a naviga­tor function that guides users to ex­periment designs appropriate for different applications.

H AutoTrack (Suprex, $495, circle 307) is a Windows application that provides monitoring and historical logging of supercritical fluid extrac­tion experiments without any need for an operator to be present.

Literature M SoftShell Catalog (SoftShell In­ternational, free, circle 308) describes software tools for chemical research and education. Products include programs that provide chemical drawing (ChemWindow and Chem-Intosh), chemical clip art, process flow diagrams, spell checking, and NMR and MS data analysis.

M Expert Search brochure (Perkin-Elmer, free, circle 309) describes Ex­pert Search for Windows, the com­pany's spectral interpretation pack­age for Fourier-transform infrared spectroscopy applications. The pro­gram includes an interpretation module that uses rules to predict structural information from spectra of unknown samples and to com­pare measured spectra against li­braries of reference spectra.

• For information on these items, see Reader Service Card

56 MAY 1, 1995 C&EN

SCIENCE/TECHNOLOGY