L.ETTEM Basic Research in the Social and Behavioral Sciences: F. T. Juster; Dairy ProductConsumption: H. R. Superko and D. Dreon...............................

ON.ORUL Materials Sciene 'and Engineering...........................................

ArRTICLES Tailored Sir cation by Ion Implanttion and Laser Treatment:S. TP L. E. Pope ...-..-.

M pothbossitian Vapor Deposition ofIHl-V Semiconductors:

SurfacebActiv : L. L. Hench and J. Wilson .......................

DuctftilOdevwd retalic Alloys: C. T. Liu and J. 0. Stiegler ...............

Multcomnponent Polymeric Engineering Materials: M. Panar and B. N. Epstein...Dynamics of Conformational Transitions in Pbolymers: E. Helfand ...............

Conducfing Organic Materials: R. L. Greene and G. B. Street...................Materials for OpticalInformation Processifng A. M. Gkass......................The Search for Very Low Loss Fiber-Optic Materials: M. E. Lines .............

N1WSCAT The Washington-Moscow Seismic Hot Line...................................The Allure of Nuclear Testing ..........................-

EPA Scraps Radionuclide Regulations........................................Schlesinger Attacks Star Wars Plan ..........................- .-

B,'efing: Connecticut Church Passes Genetics Resolution; Committee VetoesProposaito Ban Gene Tests; NASA Sumests a New Shuttle Price;Coalition Recognizes Ten Friends ofScience; Ldsat Stalled Again ........

?4o Panacea for the Firewood Crisis..........................................

610

613

615

623

630'

636

642

647

651

657

663

669

670

672

673

674

676

RRCH

boo

Vail's Sea-Level Curves Aren't Going Away .........................

The Search for a Malaria Va.ccie..... '...................

Coordinating the Effort .........................................

679

681

REVIuEn The Pro cts for, Plural Societies, reviewed by J. Vincent; UnderstandingRelatIvty, R. Paer; T Ory i A. Henderson-Selers; Quars,Gluons and at; Books Received ...................... 63

REPRTS S-Sol7-MlodeBgAreDcreased by Turbulent Convection:... .. .. .. ... .. .. ... .. . . . . .

.. ..68

Periodkity of Extinctins in the Geologic Past: Deterministic Versus StochasticExplanations: J. A. Kitchell and D. Pena .......... ................. .609

Covariace Pa;ttr of Foraminifernd 8'O0: An Evalaion of Piocene Ice Volue-Changes Near 3.2 MilUion Years Ago: W. L. PreH ................... 2

Shiga-Like Toxin-Converg Pha es from Escherichia co/i Strains That CauseHemofrhagicCitis or DatileDiarThea A. D. O'Brien et al. ............. 44

Molecular Weight DeterminatinHsofProtes by CalfrniumPlasma DesorptonMassS ect ty: . . . . . . . . . . . . .. . . . . . . . . . . . . .

Human Ornithine Transcartbmylase Locus Mapped to Band Xp2l.1 Near theDuchenne u Dystrophy Locus: V. Lindgren et al.. . . . . . . . . . ..8. -

Detection of Hgh Molecular Weight Forms of Platelet-Derived Growth Factor bySequence-Speciflc Antisera: H. L. Niman., R. A. Houghten,D. F. Bowen-Pope. ........................... ..701....

Pavoninins: Shark-Repe ing Ichthyotoxins from the Defense Secretion of thePacific Sole:Kta .K. Nakanhi ...................Tachb M. S 703

Growth Inhmitor from BSC-1 Cells Closely Reled to Platelet Type j-Transfrming Growth Factor: R. F. Tucker et al. 705 ;2'V

TranscrjWip* and.Promoter Usag of the'myc Gene in Norma So%matic andSpermatogenic Cefls: T. A. Stewart, A. R. Bellvi, P. Leder ...... 707

Unequivocal DeayedOHypersensitivity in Mast Cell-Deficient and Beige Mice:.S.J. Gal/i and l. Hazmel ............. .........

9 November 1984, Volume 226, Number 4675

AMERICAN ASSOCIATION FORTHE ADVANCEMENT OF SCIENCE Mater

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SCIE:NCE

-ials Science and Engineeringto compete in high technology will be an important determinant of

in the competition between nations and regions. In turn, successDlogy is crucially linked to leadership in materials science. Thenent of new or improved materials permits the creation of newgies, better quality control, less costly products, and, in somes, less dependence on imports of scarce elements. To advancescience requires close collaboration of physicists, chemists, and

s. Laboratory experimentation is stimulated by theoretical physi-chemists. Scientific advances also come as a result of stimulid by engineering needs. Interesting developments in materialsIre occurring; some of these are portrayed in this issue of Science.e most part, the chemistry of the substances available for use asis well known. However, the behavior of substances at surfacesfaces is not well understood. Microstructures, both in the interiorLe surface, can have a large effect on properties. One method of{ altering a surface is ion implantation, which is widely used in theluctor industry. It is also increasingly being used in other applica-rovide surfaces that differ radically in composition from the bulk oft. Intense, but short-period, laser irradiation can almost instanta-melt a shallow layer at a surface; this is followed by a comparablylification. This treatment can freeze into place microstructures withresistance to friction, wear, and corrosion. Laser treatment ofarts is now widely used in the automobile industry.rch on the surficial interactions between living tissue and prosthetichas led to potentially improved performance of the millions ofthat are done each year. Particularly useful are glasses or ceramicsIg some calcium phosphate. At the surface of the prosthetic deviceesence of body fluids, hydroxyapatite is formed. Cells recognizeLance, are compatible with it, and form connections to it.y applications, engineers seek materials that maintain their tensileat high temperatures and that are resistant to corrosion. Many ofs now in use contain imported chromium as an essential constitu-earch reported in this issue discusses the properties of Ni3Al.Iy this intermetallic alloy is brittle and unworkable. However, withion of boroi4200 parts per million), it becomes ductile. Its strengthincreases with temperatures up to 900°C, and it is comparativelyi corrosion.composites seem destined for very large-scale applications in themnd automobile industries. Already one manufacturer of airplanesunced a new model to consist largely of plastics. There will be greatn weight as well as fewer parts to assemble. A large fraction of theFiero will consist of composites. Intrinsically, some polymers are extremely strong. To use them advantageously requires age of their behavior during processing. Once strong fibers arecomposites may be created to meet engineering specifications.f the articles in this issue describe theoretical studies and researchrevolutionizing computers and data transmission. The impetus forlis work comes from the successful development of optical meansiunication with the use of glass fibers. It also is based on thenent of lasers that are capable of delivering extremely short pulses.[ple, computers based on photon processing could operate muchan the current semiconductor devices.to advance materials science will continue to be driven by

iities and international competition. Students who have an aptitudehysical sciences and a desire to participate in research with obviousrn meeting societal needs will find work in the materials sciencesIg.-PHILIP H. ABELSON