Cover; August 1998; Scientific American Magazine; by Staff Editor; 1 Page(s)

Table of Contents; August 1998; Scientific American Magazine; by Staff Editor; 2 Page(s)

From the Editors, including Masthead; August 1998; Scientific American Magazine; by Rennie; 1 Page(s)

Letters to the Editors; August 1998; Scientific American Magazine; by Staff Editor; 2 Page(s)

50, 100 and 150 Years Ago; August 1998; Scientific American Magazine; by Staff Editor; 1 Page(s)

AUGUST 1948 SPELLING BEE--Karl von Frisch, in his studies of honey bees, discovered that bees returning from a rich source of food perform special movements for other bees, which he called dancing. He distinguished between two types of dance: the circling dance (Rundtanz) where the bee circles, and the wagging dance (Schw¿nzeltanz) when it moves forward, wagging its abdomen, and turns. Von Frisch showed that the circling dance is used when the food source is closer than about 100 meters. In the wagging dance the frequency of turns indicates the distance to the food source. When the feeding place was 100 meters away, the bee made about 10 short turns in 15 seconds. To indicate a distance of 3,000 meters, it made only three long ones in the same time.

HYPERTENSION--There is a growing concern over vulnerability to high blood pressure and hardening of the arteries. Death certificates show that these associated conditions kill some 600,000 people in this country annually. Since the 18th century, life expectancy in the U.S. has increased from 39 to 57 years, largely because of the conquest of diseases such as smallpox, typhoid fever, tuberculosis, plague, diphtheria and, more recently, pneumonia and streptococcic infections. The reduction of these diseases has permitted people to live to the age when hypertension and arteriosclerosis take their greatest toll.

In Focus: Deadly Secrets; August 1998; Scientific American Magazine; by Zorpette, Beardsley; 2 Page(s)

Although observers have presumed for years that both India and Pakistan had nuclear arsenals, the 11 nuclear detonations on the Indian subcontinent in May heralded a new level of tension between foes that have fought three conventional wars in their 51-year history as independent nations. More broadly, however, the development is illustrative of the challenges facing the international community as it seeks to halt global nuclear proliferation. India and Pakistan, which took widely divergent routes to their bombs, have shown how hard it is to deny simple but effective nuclear weaponry even to relatively poor countries, how easy it is to rend the fragile de facto moratorium on the use of these munitions and how difficult it becomes to help a developing nation build nuclear reactors while ensuring that none of the aid is put to military use.

The Indian and Pakistani tests should not have been a surprise. They have roots, in fact, extending back to the early years of the nuclear era. In the 1950s, 1960s and into the 1970s, both India and Pakistan participated in nuclear cooperation efforts, most notably the Atoms for Peace program begun by the U.S. Under this program, the U.S. provided critical blueprints, know-how and components for a plant at the Bhabha Atomic Research Center in Trombay, just north of Bombay, for reprocessing the spent fuel from nuclear reactors.

A Massive Discovery; August 1998; Scientific American Magazine; by Gibbs; 2 Page(s)

Future historians may look back on 1998 as the year that particle physics got interesting again. For decades, the search for the fundamental nature of matter has been reduced to a jigsaw puzzle. The Standard Model of particle physics provided the frame, with outlines of each of the two dozen elementary particles sketched in their proper places. When an army of almost 1,000 physicists discovered the top quark in 1995, the puzzle seemed to be complete. Only a bit of bookkeeping remained: to confirm that the three lightest particles--the electron-, muonand tau-neutrinos--indeed weigh exactly nothing, as the Standard Model predicts.

But in June the 120 Japanese and American physicists of the Super-Kamiokande Collaboration presented strong evidence that at least one of the neutrinos (and probably all of them) weighs something. That neutrinos have a small mass is no small matter. It could help explain how our sun shines, how other stars explode into brilliant supernovae and why galaxies cluster in the patterns that they do. Perhaps most important, explains Lincoln Wolfenstein, a physicist at Carnegie Mellon University, "once you accept that one neutrino has mass, you realize that the truth is something beyond the Standard Model.

Beyond Physics; August 1998; Scientific American Magazine; by Gibbs; 3 Page(s)

Modern science, like every successful philosophy, has axioms that it takes on faith to be true. Allan R. Sandage, one of the fathers of modern astronomy, has just slid one of these precepts onto an overhead projector. In letters too large to ignore, it hangs before the eyes of several hundred scientists, theologians and others gathered here at the University of California at Berkeley to discuss the points of conflict and convergence between science and religion. The axiom is called Clifford¿s dictum: "It is wrong always, everywhere and for everyone to believe anything on insufficient evidence."

Is there sufficient evidence to support a belief in a Judeo-Christian God? Although many scientists working in the U.S. would doubtless agree with Sandage that "you have to answer the question of what is ¿sufficient¿ for yourself," recent polls suggest that most of them would nonetheless answer no. But the program for this conference includes some two dozen scientists, nearly all of them at the top of their fields, who have arrived at a different conclusion.

Anti Gravity: Hoop Genes; August 1998; Scientific American Magazine; by Mirsky; 2 Page(s)

You know how close I came to playing professional basketball? About 17 inches. Seventeen inches taller, and I would have been an even seven feet, which at least would have given me a shot at seeing just how close a shave Michael gets on the top of his head. Having immense strength, acrobatic agility, catlike coordination, unbridled desire and a soft touch on my fallaway jumper would also have come in handy, but the height thing couldn¿t have hurt. All of which brings us to genes.

Although the Human Genome Project will probably fail to uncover a DNA sequence governing three-point shooting, British researchers have indeed found a jock gene. The gene in question, which comes in two forms called I and D (for "insertion" and "deletion"), is for angiotensin-converting enzyme (ACE), a key player in modulating salt and water balance, blood vessel dilation and maybe more. People carrying the D form are perfectly normal but will probably be at home watching television reports of people who have the I form planting flags on the top of Mount Everest.

In Brief; August 1998; Scientific American Magazine; by Leutwyler; 3 Page(s)

New Planet? A California astronomer has snapped what appears to be the first image of a planet outside our solar system. Using the Hubble Space Telescope, Susan Terebey photographed the object, believed to be two to three times the mass of Jupiter, escaping from a pair of young binary stars 450 light-years away. The supposed planet is connected to the stars by a filament of light, probably an artifact of its trajectory. Life on the new body is unlikely, as its surface temperature is several thousands of degrees. Even so, the discovery could change ideas of how planets usually form.

Polarized Vision Researchers have figured out why squid don¿t squint: like several other colorblind animals (but unlike people), these leggy ocean dwellers are visually sensitive to polarized light. Roger T. Hanlon, director of the Marine Resources Center at the Marine Biological Laboratory in Woods Hole, Mass., and his colleagues determined that polarization helps to enhance the contrast of the squid¿s black-and-white vision--enabling it to better detect prey, such as plankton, that have evolved transparent bodies for protection from predators.

Food for Thought; August 1998; Scientific American Magazine; by Nemecek; 2 Page(s)

If diabetics don¿t eat, they stop taking insulin and can develop ketoacidosis, a potentially life-threatening complication of diabetes that can be severe enough to send someone into a coma. So when Nicole Lurie noticed that many of her diabetic patients were coming to Hennepin County Medical Center in Minneapolis with ketoacidosis because they could not afford to eat, she was understandably alarmed. Lurie, a professor of medicine and public health at the University of Minnesota, along with her colleagues Karin Nelson and Margaret E. Brown, decided to investigate just how prevalent hunger was among all their patients at the hospital. Now Lurie describes the diabetics as "canaries in the coal mine," providing advance warning of hunger¿s widespread threat to health.

The Minnesota team reported its findings in a recent issue of the Journal of the American Medical Association: of the 567 patients interviewed in early 1997, 13 percent reported that during the previous year they had, on several occasions, not eaten for an entire day, because they could not afford food. A separate survey of 170 diabetics revealed that almost 19 percent had suffered complications that resulted from not having enough money to eat. Hennepin County Medical Center, which is a public hospital in an urban setting, treats many low-income patients. Indeed, Lurie and her colleagues note that among patients reporting hunger or uncertainty about when they might eat next, many had annual incomes of less than $10,000. Many also shared another characteristic--recent reductions in their food stamp benefits.

Bright Lights, Big Mystery; August 1998; Scientific American Magazine; by Musser; 2 Page(s)

Hardly an astronomical announcement makes the front pages without being said to overturn all existing theories. Gammaray bursts are one of the few things for which this has actually been true. These seemingly random flashes--which, if you had gamma-ray vision and didn¿t blink at the wrong time, would outshine the rest of the sky--were long thought to originate in our galaxy. But that theory foundered in 1991, when the Compton Gamma Ray Observatory satellite detected bursts all over the sky, not only in the Milky Way. Another hypothesis, in which bursts occur just outside our galaxy, crumbled last year when the first distance measurement of a burst put it too far away. Although astronomers now agree that the bursts are some kind of megaexplosion in distant galaxies, they still appear on most top-10 lists of cosmic mysteries.

This past spring astronomers reported the distances to two new bursts-- which, at first glance, seemed to scuttle some of the few remaining plausible explanations. The first of these bursts, spotted last December 14 by the Beppo- SAX satellite, occurred in a galaxy 12 billion light-years away, according to observations by Shrinivas R. Kulkarni and S. George Djorgovski of the California Institute of Technology. To be so bright at such a distance, the burst must have shone more brilliantly than any object previously recorded.

By the Numbers: Amphibians at Risk; August 1998; Scientific American Magazine; by Doyle; 1 Page(s)

Some 5,000 species of amphibians inhabit the world, mostly frogs, toads and salamanders, and they seem to be dying at unprecedented rates. This situation has raised alarm because amphibians are widely regarded as uniquely sensitive indicators of the planet¿s health. Much of the damage to amphibians comes from habitat destruction, particularly the draining of wetlands, but what has scientists particularly worried are the declines and apparent extinctions in areas far removed from obvious human intrusion, such as the cloud forest at Monteverde, Costa Rica, where the golden toad, once abundant, has not been seen since 1989.

Do reports such as these indicate a worldwide amphibian crisis? Not necessarily, according to Joseph Pechmann of Florida International University, whose work suggests that reported declines and extinctions in near-pristine environments could simply be natural year-to-year variations: a drought, for instance, that affects egg laying and larvae survival. Because of such fluctuations, it is often impossible, in the absence of more complete historical information, to judge whether a reported decline is natural or a reaction to human activity. On the other hand, many researchers, including Andrew R. Blaustein of Oregon State University, believe the reported rates of decline and extinction are so extraordinary that they cannot be a part of the natural cycle.

Profile: An Express Route to the Genome?; August 1998; Scientific American Magazine; by Beardsley; 3 Page(s)

Jcraig Venter, the voluble director of the Institute for Genomic Research (TIGR) in Rockville, Md., is much in demand these days. A tireless self-promoter, Venter set off shock waves in the world of human genetics in May by announcing, via the front page of the New York Times, a privately funded $300-million, threeyear initiative to determine the sequence of almost all the three billion chemical units that make up human DNA, otherwise known as the genome. The claim prompted incredulous responses from mainstream scientists engaged in the international Human Genome Project, which was started in 1990 and aims to learn the complete sequence by 2005. This publicly funded effort would cost about 10 times as much as Venter¿s scheme. But Venter¿s credentials mean that genome scientists have to take his plan seriously.

In 1995 Venter surprised geneticists by publishing the first complete DNA sequence of a free-living organism, the bacterium Haemophilus in- fluenzae, which can cause meningitis and deafness. This achievement made use of a then novel technique known as whole-genome shotgun cloning and "changed all the concepts" in the field, Venter declares: "You could see the power of having 100 percent of every gene. It¿s going to be the future of biology and medicine and our species." He followed up over the next two and a half years with complete or partial DNA sequences of several more microbes, including agents that cause Lyme disease, stomach ulcers and malaria.

Trade Rules; August 1998; Scientific American Magazine; by Holloway; 3 Page(s)

The 1990s have seen the emergence of a conciliatory credo: business and environmental interests are not just compatible, they are inextricable. A healthy environment and natural-resource base are prerequisites for a healthy economy; a smoothly functioning world market, in turn, produces the resources and mind-set needed to protect the environment. Concepts such as "sustainable development" and "eco-labeling" have accordingly promised consumers a hand in making the market environmentally accountable.

Although the rhetoric seems reasonable to many on both sides of the divide, it is proving difficult to implement. As an April decision by the World Trade Organization (WTO) indicates, the interests of one nation¿s consumers may be consistently forced to yield to the interests of free trade. The ruling stated that a U.S. law prohibiting the import of shrimp caught in nets that can entrap sea turtles was a barrier to trade. According to the WTO, the U.S. must import shrimp from Thailand, Malaysia, India and Pakistan--regardless of whether the harvests endanger sea turtles-- or face large fines.

The "Other" Computer Problem; August 1998; Scientific American Magazine; by Hayashi; 3 Page(s)

In May the European Union moved one step closer to economic superpower when it officially adopted the euro as the single currency for 11 of its member nations. But as politicians celebrated, computer managers around the world issued a collective moan. They must now refit every system that deals in marks, francs, guilders and other coins of the continent to handle the new currency, which will be phased in starting in January 1999. Faced with both the euro and widespread year 2000 bugs, "a lot of companies in Europe will find themselves in dire straits," predicts Achi Racov, the chief information officer of the London-based NatWest Group. He expects that his firm will spend in excess of ¿200 million (about $320 million) to enable its systems to handle both the euro and the turn of the millennium.

Adding a new currency to financial systems sounds straightforward, but it is not. The European Commission in Brussels has published strict rules that computers must follow. Converting from francs to marks, for example, could soon require "triangulation," in which francs are changed first into euros, then into marks. Some software will need to display both the local currency and the euro during the transition period, from 1999 to 2002. And terabytes of historical financial data must eventually be converted into euros.

Look for the Union Label; August 1998; Scientific American Magazine; by Wallich; 2 Page(s)

After nearly a century of unionmanagement warfare in the U.S., a series of nationwide surveys showing that union shops dominate the ranks of the country¿s most productive workplaces may come as a surprise. In fact, according to Lisa M. Lynch of Tufts University and Sandra E. Black of the Federal Reserve Bank of New York, economic Darwinism--the survival of the fittest championed by generations of hard-nosed tycoons--may be doing what legions of organizers could not: putting an end to autocratic bosses and regimented workplaces.

American industry has been trying to reinvent itself for more than 20 years. Management gurus have proclaimed Theories X, Y and Z, not to mention Quality Circles, Total Quality Management (TQM) and High-Output Management. Only in the past few years, however, have any solid data become available on which techniques work and which don¿t. Businesses do not always respond to surveys, and previous attempts to collect data ran into response rates of as low as 6 percent, making their results unrepresentative. Enter the U.S. Census¿s Educational Quality of the Workforce National Employer Survey, first conducted in 1994, which collected data on business practices from a nationally representative sample of more than 1,500 workplaces.

Cyber View: Access Denied; August 1998; Scientific American Magazine; by Grossman; 1 Page(s)

With all the advances toward equality for women, you¿ve got to assume there are lots of women programmers, right? After all, it¿s not as though computer science is a discipline that requires more brawn than brains. But no: according to statistics compiled by Tracy K. Camp, then an assistant professor of computer science at the University of Alabama, the number of undergraduate degrees in computer science that is awarded to women has been shrinking steadily, both in real numbers and as a percentage of degrees awarded.

For instance, in the academic year 1980-81, women obtained 32.5 percent of the bachelor¿s degrees in computer science; the figure for 1993-94 was 28.4 percent, a drop of 12.6 percent. Calculated from the peak year in 1983-84, when 37.1 percent of the degrees went to women (representing 32,172 B.A. and B.S. degrees), the total decline is an alarming 23.5 percent.

Fusion and the Z Pinch; August 1998; Scientific American Magazine; by Yonas; 6 Page(s)

Some things never change--or do they? In 1978 fusion research had been under way almost 30 years, and ignition had been achieved only in the hydrogen bomb. Nevertheless, I declared in Scientific American at the time that a proof of principle of laboratory fusion was less than 10 years away and that, with this accomplished, we could move on to fusion power plants [see "Fusion Power with Particle Beams," Scientific American, November 1978]. Our motivation, then as now, was the knowledge that a thimbleful of liquid heavy-hydrogen fuel could produce as much energy as 20 tons of coal.

Today researchers have been pursuing the Holy Grail of fusion for almost 50 years. Ignition, they say, is still "10 years away." The 1970s energy crisis is long forgotten, and the patience of our supporters is strained, to say the least. Less than three years ago I thought about pulling the plug on work at Sandia National Laboratories that was still a factor of 50 away from the power required to light the fusion fire. Since then, however, our success in generating powerful x-ray pulses using a new kind of device called the Z machine has restored my belief that triggering fusion in the laboratory may indeed be feasible in 10 years.

Low-Back Pain; August 1998; Scientific American Magazine; by Deyo; 6 Page(s)

The catalogue of life¿s certainties is usually limited to death and taxes. A more realistic list would include low-back pain. Up to 80 percent of all adults will eventually experience back pain, and it is a leading reason for physician office visits, for hospitalization and surgery, and for work disability. The annual combined cost of back pain¿related medical care and disability compensation may reach $50 billion in the U.S. Clearly, back pain is one of society¿s most significant nonlethal medical conditions. And yet the prevalence of back pain is perhaps matched in degree only by the lingering mystery accompanying it.

Consider the following paradox. The American economy is increasingly postindustrial, with less heavy labor, more automation and more robotics, and medicine has consistently improved diagnostic imaging of the spine and developed new forms of surgical and nonsurgical therapy. But work disability caused by back pain has steadily risen. Calling a physician a back-pain expert, therefore, is perhaps faint praise--medicine has at best a limited understanding of the condition. In fact, medicine¿s reliance on outdated ideas may have actually contributed to the problem. Old concepts were supported only by weak evidence such as physiological inferences and case reports, rather than by clinical findings from rigorous controlled trials.

Computing with DNA; August 1998; Scientific American Magazine; by Adleman; 8 Page(s)

Computer. The word conjures up images of keyboards and monitors. Terms like "ROM," "RAM," "gigabyte" and "megahertz" come to mind. We have grown accustomed to the idea that computation takes place using electronic components on a silicon substrate.

But must it be this way? The computer that you are using to read these words bears little resemblance to a PC. Perhaps our view of computation is too limited. What if computers were ubiquitous and could be found in many forms? Could a liquid computer exist in which interacting molecules perform computations? The answer is yes. This is the story of the DNA computer.

Monitoring and Controlling Debris in Space; August 1998; Scientific American Magazine; by Johnson; 6 Page(s)

Since the space age began four decades ago, rockets have lifted more than 20,000 metric tons of material into orbit. Today 4,500 tons remain in the form of nearly 10,000 "resident space objects," only 5 percent of which are functioning spacecraft. These objects are just the large ones that military radars and telescopes can track. Of increasing interest to spacecraft operators are the millions of smaller, untrackable scraps scattered into orbits throughout near-Earth space, from only a few hundred kilometers to more than 40,000 kilometers (25,000 miles) above the surface of the planet.

If Earth¿s tiny attendants moved like the hordes of miniature moons around Jupiter or Saturn, they would be a thing of beauty. The rings of the giant planets are finely orchestrated; their constituent rocks and chunks of ice orbit in well-behaved patterns, and collisions between them occur at gentle velocities. But Earth¿s artificial satellites resemble angry bees around a beehive, seeming to move randomly in all directions. The population density of satellites is fairly low; the region around Earth is still a vacuum by any terrestrial standard. But the haphazard motions of the swarm lead to huge relative velocities when objects accidentally collide. A collision with a one-centimeter pebble can destroy a spacecraft. Even a single one-millimeter grain could wreck a mission.

A Quarter-Century of Recreational Mathematics; August 1998; Scientific American Magazine; by Gardner; 8 Page(s)

My "Mathematical Games" column began in the December 1956 issue of Scientific American with an article on hexaflexagons. These curious structures, created by folding an ordinary strip of paper into a hexagon and then gluing the ends together, could be turned inside out repeatedly, revealing one or more hidden faces. The structures were invented in 1939 by a group of Princeton University graduate students. Hexaflexagons are fun to play with, but more important, they show the link between recreational puzzles and "serious" mathematics: one of their inventors was Richard Feynman, who went on to become one of the most famous theoretical physicists of the century.

At the time I started my column, only a few books on recreational mathematics were in print. The classic of the genre--Mathematical Recreations and Essays, written by the eminent English mathematician W. W. Rouse Ball in 1892--was available in a version updated by another legendary figure, the Canadian geometer H.S.M. Coxeter. Dover Publications had put out a translation from the French of La Math¿matique des Jeux (Mathematical Recreations), by Belgian number theorist Maurice Kraitchik. But aside from a few other puzzle collections, that was about it.

Irrigating Crops with Seawater; August 1998; Scientific American Magazine; by Glenn, Brown, O'Leary; 6 Page(s)

Earth may be the Ocean Planet, but most terrestrial creatures-- including humans--depend for food on plants irrigated by freshwater from rainfall, rivers, lakes, springs and streams. None of the top five plants eaten by people--wheat, corn, rice, potatoes and soybeans--can tolerate salt: expose them to seawater, and they droop, shrivel and die within days.

One of the most urgent global problems is finding enough water and land to support the world¿s food needs. The United Nations Food and Agriculture Organization estimates that an additional 200 million hectares (494.2 million acres) of new cropland--an area the size of Arizona, New Mexico, Utah, Colorado, Idaho, Wyoming and Montana combined--will be needed over the next 30 years just to feed the burgeoning populations of the tropics and subtropics. Yet only 93 million hectares are available in these nations for farms to expand-- and much of that land is forested and should be preserved. Clearly, we need alternative sources of water and land on which to grow crops.

Microdiamonds; August 1998; Scientific American Magazine; by Trautman, Griffin, Scharf; 6 Page(s)

Diamond has been a highly valued mineral for 3,000 years. In ancient India the gemstone was thought to possess magical powers conferred by the gods. Medieval European nobles sometimes wore diamond rings into battle, thinking the jewelry would bring them courage and make them fearless.

More recently, diamond has proved to be the ideal material for a number of industrial uses. The mineral, an incredibly pure composition of more than 99 percent carbon, is the hardest substance known. It is capable of scratching almost anything, making it suitable for use in abrasives and in cutting, grinding and polishing tools. Diamond also has high thermal conductivity--more than three times that of copper--and is thus optimal for spreading and dissipating heat in electronic devices such as semiconductor lasers. Because most of these applications can be accomplished with tiny crystals, both scientific and technological interest have begun to focus on microdiamonds, samples that measure less than half a millimeter in any dimension.

The Philadelphia Yellow Fever Epidemic of 1793; August 1998; Scientific American Magazine; by Foster, Jenkins, Toogood; 6 Page(s)

Epidemics that quickly wipe out large segments of communities are rare in the U.S. these days. But before the 20th century, such disasters occurred quite frequently, ravaging bewildered populations who usually had little understanding of the causes. Apart from the human tragedies these episodes produced, some had lasting political effects on the nation. A dramatic example arose in 1793, when one of the earliest significant epidemics of yellow fever in the U.S. struck Philadelphia, then the nation¿s capital.

At the time, Philadelphia was the country¿s largest and most cosmopolitan city. Yet prominence and prosperity offered little protection. Over the summer and fall, roughly a tenth of its population, some 5,000 people, perished.

The Amateur Scientist; August 1998; Scientific American Magazine; by Carlson; 2 Page(s)

Okay, I'll confess: my scientific specialty is nuclear physics, but I would much rather trace the course of a quiet stream than find my way along a linear accelerator any day. And ecology, especially stream ecology, affords more opportunities for meaningful amateur research. Indeed, the techniques used are so straightforward and the results so immediate that you can easily craft wonderful scientific experiences for your whole family with just a little preparation. And you can forge ties with others, too--with the rise of the environmental movement, thousands of part-time naturalists have banded together into nearly 800 independent organizations that work to assess the health of our nation's watersheds. These associations can help you and your family jump into this rich and rewarding area of research.

Some of these groups have just a few members and operate on a shoestring. Others have hundreds of participants and annual budgets of tens of thousands of dollars. Some limit their activities to physical and biological surveys: they record the temperature, rate of flow and clarity of the water, or they take a regular census of the seasonal inhabitants of a stream. Other groups have the equipment to measure dissolved oxygen and pH levels, check for fecal coliform bacteria and test for various pollutants. All these volunteers make important contributions to bettering the environment, albeit one stream at a time.

Mathematical Recreations; August 1998; Scientific American Magazine; by Stewart; 2 Page(s)

The extremely polite monks of the Perplexian order like to play logical tricks on one another. One night, while Brothers Archibald and Benedict are asleep, Brother Jonah sneaks into their room and paints a blue blob on each of their shaved heads. When they wake up, each notices the blob on the head of the other but, being polite, says nothing. Each vaguely wonders if he, too, has a blob but is too polite to ask. Then Brother Zeno, who has never quite learned the art of tact, enters the cell and begins giggling. On being questioned, he says only, "At least one of you has a blue blob on his head."

Of course, both monks already know that. But then Archibald starts thinking: "I know Benedict has a blob, but he doesn¿t know that. Do I have a blob? Well, suppose I don¿t have a blob. Then Benedict will be able to see I don¿t have a blob and will immediately deduce from Zeno¿s remark that he must have a blob. But he hasn¿t shown any sign of embarrassment--oops, that means I must have a blob!" At which point, he blushes bright red. Benedict also blushes at about the same instant, for much the same reason. Without Zeno¿s remark, neither train of thought could have been set in motion, yet Zeno tells them nothing--apparently--that they do not know already.

Reviews; August 1998; Scientific American Magazine; by Branscomb, Raven; 3 Page(s)

One decade ago the Massachusetts Institute of Technology assembled a Commission on Industrial Productivity to examine the reasons American dominance of high-technology industry was experiencing a serious competitive decline. The commission¿s 1989 book, Made in America: Regaining the Productive Edge, documented the problems in a number of industries--problems that were evidenced by poor product quality, noncompetitive production costs and excessively long product cycles, as compared with best practice in Asia. The most painful part of this realization was that the decline affected not only steel, textiles and automobiles but also the high-tech microelectronics, computer and communications industries. This book was a call to arms. What were Americans doing wrong? How could we fix it?

Now the leader of the team that wrote Made in America has come out with a sequel, borrowing the title from the subtitle of the earlier study. But the question now being asked is not what did we do wrong, but what are we doing right? Lester examines the easy answers and finds some truth in all of them: our most threatening competitor, Japan, was struggling with the rupture of the "bubble" economy and no longer had almost unlimited access to capital. After the profligate public borrowing of the Reagan administration, politicians of both parties committed themselves to bringing the federal budget into balance. Exchange rates had altered dramatically throughout the 1980s, with the U.S. dollar losing half its value against the yen. And most important--and clearly a matter of serious concern for the future--U. S. wages had reversed their traditional course. Union membership in manufacturing was declining; firms were reducing costs by laying off middle managers who could find only lower-paying jobs.

Commentary: Wonders - The Left and the Right; August 1998; Scientific American Magazine; by Morrison, Morrison; 2 Page(s)

In 1848 the king of France abdicated his constitutional post--not that he was the only king in Europe to be replaced by republics in those times. Yet the older regime came back; even emperors remained through World War I. That same spring of 1848 an eloquent and enduring pamphlet appeared, the Communist Manifesto of Karl Marx and Friedrich Engels. Its radical appeal would sound throughout the entire 20th century; its critique still defines political Right from Left, even though the demise it prophesied seems farther off than ever after 150 years. The metaphor of right and left is powerful among us still, but at the molecular level, that literal distinction is a rigorous and subtle property of three-dimensional space. And it was in 1848 that its consequences for matter first became clear.

No familiar molecular formula that accounts for the kinds and numbers of atoms present, such as H2O, is enough to fix its shape fully. All atom-to-atom links must be described geometrically. In a plane that is easy, but in real 3-D it is trickier. A right glove is so similar to the left glove of its pair that a basic description often fits both, although we know that the two gloves cannot equally fit either hand. Each glove matches exactly the image of its partner in an ideal mirror. Mirror-image molecular pairs possess what we call handedness; the chemists term them enantiomers, from the Greek for "opposites."

Commentary: Connections - Tick Tock; August 1998; Scientific American Magazine; by Burke; 2 Page(s)

Walking through Parliament Square in London the other day, I suddenly remembered that when I was a very small child during World War II, the sound of Big Ben ringing the hour on the radio was a comforting indication that it hadn¿t been hit by incoming German V-1 missiles.

In 1859 the new Big Ben clock became the miracle of harrumph high-tech precision (as had been promised by Prime Minister George Canning) when the gravity escapement system created by E. Beckett Denison was installed. Denison¿s trick for isolating the movement of the pendulum from that of the gears worked in such a way that no matter how much dirt or ice accumulated on the four sets of clock hands, Big Ben would keep time accurate to the second. (Thank you, Frederickton, New Brunswick, on whose often icy cathedral clock Denison had done a wet run.)

Working Knowledge; August 1998; Scientific American Magazine; by Bowden; 1 Page(s)

The demand regulator, which connects a high-pressure scuba tank to a breathing mouthpiece, opened the vast world beneath the waves to hundreds of millions of people. It is not much to look at, but this remarkable device enables anyone in reasonably good health to see what people could only imagine or speculate about for thousands of years. In so doing, it transformed perceptions of the undersea domain from that of a mysterious place having dark and often fearsome connotations to a more familiar realm known mainly for its beauty and wonder.

A regulator enables a diver to breathe comfortably underwater by regulating the tank¿s high-pressure breathing gas, matching the gas pressure to the ambient pressure at whatever depth the diver happens to be. This regulation takes place in two stages. The first stage reduces the tank pressure, which is typically about 3,000 pounds per square inch (psi) in a full tank, to an intermediate pressure between 90 and 140 psi. The second stage then reduces the intermediate pressure to the ambient pressure-- 44 psi at a depth of 66 feet in seawater, for example, or 59 psi at 100 feet.