The Boston Globe du lieu suivant : Boston, Massachusetts • 46

46 THE BOSTON GLOBE MONDAY. APRIL 15, 1985 No errors allowed in this ballgame SCIENCE WORLD The other spring marathon By Jodie Ann Limon Special to The Globe addition to the Boston Marathon, there's a mass crosscountry event taking place this spring that is signalled by a dark, drizzly night after a long day of warm rain. From subterranean hibernation burrows in the damp woodlands of Massachusetts, thousands emerge to take globe staff file photo by GEORGE RIZER SCHEDULE-MAKERS Continued from Page 45 ematical Sciences Research Center at Bell Laboratories, says the key to successful scheduling is to limit the problem before you even begin to attack it. If the computer is forced to look at every possible scheduling option it will suffer a "combinatorial explosion," and churn out possible solutions for months or even years before it hits upon the best one. To illustrate, Graham cites the classic traveling salesman problem, in which a salesman plans a crosscountry trip to several towns.

His goal is to make sales calls in each town, keeping his mileage to a minimum and returning home without visiting any town twice. Arranging a five-town trip is fairly easy, but mathematicians who specialize in a field called combinatorics calculate that a 20-town tour would keep even the fastest computer crunching away for 3000 years. The 'hard problems' This kind of problem, in which complexity increases dramatically with even a slight jump in the number of different variables (in this case towns) belongs to a category known as NP-complete, also called, perhaps more aptly, the "hard problems." Hard problems are hard because every change in a variable alters the remainder of the problem there's no such thing as an isolated decision: every decision affects every other move. For example, if a trip to Buffalo gets swapped with a trip to Washington, D.C.. the whole itinerary has to be redone.

Baseball scheduling is another hard problem, and the more teams involved, the vastly more difficult it gets. So far, NP-complete problems have not lent themselves to fast, easy computerized solutions. The salesman limits his options, or as Graham puts it "confines the problem" by applying some common sense. For instance, he rejects a trip that would entail flying to San Jose from Boston, then calling on a New York City firm before heading off to close a deal in Portland. Ore.

But a computer has no common sense; it has to be told everything, including that bouncing around from coast to coast is no way to run a profitable business. No computer can accommodate all the "rules of thumb" inherent in or- ganizing something as complex an annual, virtually undetected trek across a treacherous course to small, temporary ponds throughout the state. There they perform a mysterious nuptial dance, and then just as Invisibly they journey back to the moist shelter of logs and rocks. This strange triathalon Is the night of the salamander, and it too has loyal fans who patiently line the chilly, misty route to watch the spectacle. Fourth survey The spectators for this competition are a network of volunteers participating In the fourth annual statewide Salamander Survey, which takes place In late March and early April.

The project is co-ordinated by the Massachusetts Natural Heritage Program (MNHP) of the Division of Fisheries and Wildlife as part of a continuing effort to obtain Information on the current status and location of rare or ecologically sensitive animal populations throughout the state. The role of those faithful, flashlight-bearing Individuals, who yearly monitor breeding ponds where upwards of 100 salamanders may mate at any one time, is to provide a detailed play-by-play on species, numbers, locations, and evidence of egg masses of migrating salamanders. Last year, 70 volunteers repor observations of eight species of salamanders from more than 120 sites in 67 towns, allowing biologists to trace population distributions and trends. The MNHP uses the information to assess endangered habitats and formulate protection plans for vulnerable rare species of salamanders. The categories of contestants in this case species belong to the Ambystomld family of 4-7 inch mole salamanders, although other amphibians may participate.

The most common Ambystomid Is the stout, black, spotted salamander, found throughout the state excluding the islands, and recognized by its double row of Irregular yellow spots extending from eyes to tail. The long, slender, blue-flecked Jefferson salamander is distinguished in part by its conspicuously long toes. It is often confused with the closely related, smaller, narrower-snouted blue-spotted salamander, which sports a profuse array of bluish-white spots giving it an enameled appearance. Both of these species feature biologically unique triploid females who reproduce asexually by the process of gynogenesis, essentially creating perfect clones of themselves. The rarest entrant In the salamander triathlon, and perhaps most beautiful of the family, is the stocky, black-gray marbled salamander, strikingly marked with variable cross-bands of gray or white, and distinct in its preference for fall courtship.

Many obstacles These amphibian marathoners must survive numerous obstacles along the path to fulfilling their romantic aspirations. Their concentrated spring migrations are threatened by human collecting pressures and automobile traffic, and their temporary natal ponds are highly sensitive to pollution and loss to, development. The greatest stress on salamanders, however, may result from the acid rain and snow that melts to fill their vernal ponds and increase the acidity of the environment in which eggs and larvae develop. Laboratory experiments performed by a number of researchers, including herpetologist Pe- ter Mirick with the Massachusetts Division of Fisheries and Wildlife, suggest a relationship between malformation and death in salamander embryos and larvae and a low pH aquatic habitat. Salamander marathoners are living barometers of the damage caused by acid precipitation and hazardous waste, in addition to their esential role' as insect predators, soil aerators and recyclers, and prey to larger animals.

The health of their populations is an Indicator of a stable ecosystem, while their disappearance serves as an alarm to a break In the delicate web of biological diversity. Limon is a freelance writer who lives in Brookline. Computer assures big sports day and subjective as a major league baseball schedule. That's where the Stephensons come in. "People think we just lift the lid of a machine, throw in some information and wait for results," Henry says.

"But the computer is only an assistant we are the schedule-makers." The Stephen-sons do the thinking and negotiating with team representatives, the computer does the calculating and makes sure that the unthinkable like two teams getting scheduled to play the same opponent on the same day never happens. Scheduling baseball wasn't always so difficult. Robert Holbrook, a consultant with the American League who lives in Wellesley, has helped negotiate the American League schedule for the past 19 years. He says the longer distances made possible by air travel and an increase in the number of teams, both of which began in the late 1950s, have caused most of the problems. "When we had eight teams to a league things were a lot easier," says Holbrook.

"Each team played every other team 22 times, which meant 1 1 home games and 1 1 away games. We never played west of St. Louis because the trains took too long to get there. But now. there are so many teams and the geography involved is so vast that we just Quick action limiting stroke 'There is now a much better understanding that stroke is a continuing process, that we can interfere with these processes before they go too Dr.

Michael Walker SCIENCE UPDATE in Boston: Sox plus the marathon. had to get into the computer age. The computer is a super auditing vehicle, and the Stephensons are my pride and joy." But before Holbrook signed on the Stephensons in 1981. the baseball schedule was the purview of a man without a machine: Harry Simmons. A former public relations representative for the International League and member of the office staff of the baseball commissioner, Simmons handled the schedule for 40 years.

Simmons knows more about baseball than just about anyone, and proves it every month with a column he writes for Baseball Digest entitled "So You Think You Know Baseball?" He is described by his former colleagues as a scheduling "genius." Develop a pattern Now retired and living in Montreal, Simmons says scheduling baseball is a lot like playing chess, a game in which he excels. "It's all strategy," he says. "You develop a pattern and then you expand it to accommodate however many games are involved." But when the American League expanded to 14 teams, Simmons realized the problem had become too tough for even a scheduling ace like himself. "What a headache that was," he says. "It took and, US scientists note, in uncontrolled human trials in Japan.

Naloxone, a drug already approved by the US Food and Drug Administration to combat drug addiction. The drug appears able to keep up crucial heart output and thus the brain's blood supply if given immediately following stroke in animals, notes Dr. Michael Lavyne, a neurosurgeon at New York Hospital Cornell University Medical Center. Human trials are under way. Four months ago, a team of Swedish researchers led by Dr.

Tage Strand reported In the American medical journal Stroke that a blood-thinning drug called dextran given right after stroke dramatically improves a patient's chances of being able to live at home and of walking unaided three months afterwards. "The Swedish results," says Dr. Robert J. White, professor of neurosurgery at Case Western Reserve University Medical School, "look awfully good." Neurological improvement The Swedish team compared 52 patients who had been randomly assigned to receive dextran with 50 others who did not receive the drug. Both groups, according to the researchers, had similar chances for recovery.

In the first 1 0 days after stroke, 85 percent of the patients who received dextran Improved neurologlcally, compared to only 64 percent of the others. Dextran had no apparent effect on survival, however. About one quarter of both groups had died by the three-month follow-up point. Dr. James H.

Wood, director of the cerebral blood flow laboratory at Emory University, has had similarly encouraging results with a smaller group of pattWs using a different blood thinner. me three or four months to get the schedule together. It much easier with the computer, but vou still have to tell the machine what to do." The Stephensons won't say exactly what tricks they use to coax the schedule out of their IMS 800 microcomputer, but Henry says the thing to keep in mind is that every home game is also an away game. "The trick is balancing the conflicting requirements of the two," he smiles. "We're constantly mixing apples with oranges." And no matter who wins the game, the schedule-maker is always the loser.

"You know when you see an umpire nose-to-nose with a manager getting dirt kicked on his shoes?" Henry asks. "We get plenty of dirt kicked on ours too." But according to Holbrook, the Red Sox do very little kicking. "The Red Sox are easy to deal with because they're doing so well and always draw a big crowd," he says. "They could play at 3 a.m. and still fill Fenway Park.

When a team wins it loves the schedule. But when it loses, it's always the schedule-maker's fault. I'll tell you, drawing up baseball schedules is a thankless task." Shell is a freelance writer who lives in Boston. damage Wood explains that thinning the blood of stroke patients allows it to move faster and more easily into the collateral arteries In the brain, which can temporarily take over when larger vessels become blocked. About eight out of every 10 American stroke victims "are potential candidates for this therapy." he says, because their strokes are caused by vessel blockage, as opposed to hemorrhages.

But an even more daring strategy may emerge from animal studies. Fluorocarbon solutions containing oxygen can be injected into the blood of animals given experimentally induced strokes, says Dr. Sidney Peerless, chairman of the department of neurosurgery at the University of Western Ontario. This "supercharges" the blood with oxygen-carrying molecules that are much smaller than red blood cells and hence are able to penetrate brain cells cut off from the main blood supply. But a team of researchers at Jefferson Medical College of Thomas Jefferson University in Philadelphia have taken Peerless' work one step further in work reported In the journals Neurosurgery and Brain Research.

Instead of injecting a fluorocarbon solution into the blood of experimental animals, Dr. Jewell Osterholm, pharmacologist Anthony Trlolo and their team Injected it directly Into the ventricles, or spaces, in the animals' brains, bypassing the circulatory system altogether. Such work is a long way from helping human patients. Less brain damage But the animals Injected with fluorocarbon retained more neurological function than control animals, and showed 80 percent less Irreversible brain damage. This is particularly striking because some of the animals had had no brain activity, as shown by flat EEGs (electroencephalograms), for at least 10 minutes.

In 37 states, a human being who has two flat EEGs 24 hours apart is declared legally dead. If this dramatic resuscltative brain treatment Is ever applied In humans, say some observers. It could necessitate yet another fine-tuning of the criteria that determine when a brain and r)ence, a person Is truly dead. STROKE Continued from Page 45 In the bypass operation, a surgeon works through a silver-dollar-sized hole in the skull to connect the artery whose pulse can be felt at the temple to a nearby cerebral artery within the skull. (The temporal artery is supplied by the external carotid artery, which, uniike the internal carotid artery, does not usually become blocked with plaque.) Important as Barnett's study is expected to be, it is but one of several areas of ostensible progress in the treatment of strokes: Blood thinning, called hemo-dilution.

Blood thinned with an artificial blood substitute that can carry oxygen makes it more slippery and faster-flowing, allowing it to pass into smaller, collateral blood vessels, studies in Sweden and at Emory University in Atlanta show. Drugs known as calcium-channel blockers. Such drugs, al- ready used for heart patients, are being tested on stroke patients at 10 US medical centers and will be part of an even larger National Institutes of Health study. The drugs appear to block two major problems that follow strokes: death of brain cells due to an in-pouring of calcium from surrounding fluids, and the destructive spasms of I blood vessels after stroke. Heparinoids, a new type of anticoagulant drug.

Spin-offs of the traditional anticlotting agent heparin, heparinoids will be tested in national drug trials now being set up. Unlike heparin, which can provoke hemorrhage, the heparinoids just block clots. Enzymes that "lyse" or chew up clots. Traditionally, enzymes such as streptokinase have been used to destroy clots in coronary arteries, but they have always been deemed too toxic for use in the brain (and, recent research shows, perhaps too toxic for the rest of the body as well). But close cousins of such enzymes "will be most promising molecules in the future," contends Dr.

Michael A. Moskowitz, director of the stroke research laboratory at MGH. Oxygen-carrying fluorocar-bon solutions. Such solutions appear able to keep endangered brain areas alive during a stroke, at least in animal experiments in Canada and the United States Lobsters and manic-depressives Lobsters are aggressive and cannibalistic, but hormonal studies attempting to depress the cranky crustaceans may hold the key to controlling mood swings in manic-depressive humans, according to researchers at the University of New England College of Osteopathic Medicine. The neuro-hormone serotonin, which is found in nearly every animal and In humans, may possibly be linked to the aggressive behavior in lobsters.

Serotin is circulated in a lobster's bloodstream while in humans the mood-swinging hormone is isolated in the brain. Previous scientific studies have shown that serotonin levels In monkeys rise and fall depending on their status In the animal community. In humans, low levels of the neuro-hormone are correlated with certain types of manic-depressive bahavior, said physiologist Carl Spirito. The world's sinking cities Many of the world's great cities are slowly sinking. Although urban areas have been sinking for hundreds of years from the weight of building structures and progressively higher tides, severe problems have developed over the last 40 years, according to two University of Virginia environmental scientists.

Since 60 percent of the world's population lives In coastal regions the staggering economic costs of protecting sinking coastal cities from flooding will create difficult choices about which areas to protect. The problems are worsened by the extraction of ground water from aquifers beneath the cities. When pressure In the aquifers drop, compaction occurs. In addition to Venice, some of the major sinking cities around the world include London, Bangkok, Mexico City, and Tokyo. Sinking cities in the United States Include Long Beach and much of the San Joaquin Valley of California; the Houston and Galveston.

Texas area; New Orleans, and Savannah, Ga. Tribal homosexuality in the Pacific More than 30 different tribes In New Guinea. New Caledonia, theFiji Islands, New Hebrides and New Britain practice or once practiced some form of Institutionalized homosexuality, according to a Stanford anthropologist. In many cases, all the young males of a tribe are expected to have homosexual relations for years at a time as part of a secret cult, a practice kept hidden from the women and children of the tribe. Once the boys are adults, however, they marry and usually assume heterosexual relations for the remainder of their lives, although they continue to display an Intense sexual antagonism toward the women, said anthropologist Gilbert Herdt.

Traditionally these peoples believed that the prolonged ritualized homosexual experience served as a way to keep the society militarily strong, by transforming boys Into men. so that they become aggressive and brave and ready for Rattle. SCIENCE CALENDAR Wednesday, April 17 "Hazardous Waste: The Search for Solutions." Film and discussion on toxic wastes. 7:30 p.m.. Room 100, Building 54, MIT.

Thursday, April 18 "The Second Self: Computers and the Human Spirit." Lecture by MIT Associate Professor Sherry Turkle on the changes the computer has made In American society, 7 p.m., The Computer Museum. 300 Congress st. Admission: $4 adults, $2 students. "New Methods In X-Ray Imaging." Nontechnical illustrated lecture by Dr. Leon Golub, 8 p.m..

Center for Astrophysics. 60 Garden Cambridge. Sunday, April 21 "Computer Holographies." Lecture by Dr. Stephen Benton on state-of-the-art holographies. 4 p.m..

The Computer Museum, 300 Congress st. Admission: $4 adylts. $2 students..