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Show SENIOR CARE Wellness andliving wills Aclass series for caregivers of elderly relatives or friends will continue throughout the summerat Utah Valley Regional Medical Center in Provo. Classes are every Wednesday at 4 p.m., in the hospital’'s Northwest Plaza, classroom 3. Theseries includes eight classes, covering suchtopics as long-term MESA VERDE Hansen Planetariumstar party of the park and overnightstay (double occupancy) at Far View Lodge,the only lodge inside the park. Planetarium staff will provide telescopes and a slide presentation on the Hubble space telescope. The park is 358 miles Check this site care,including dem The nonprofit Environmental Working Grouphas ted June 10 and the Murray City He tage Center, 10 E. 61 an interactive Website www.foodnews.org that tells users whatkindsof pes ticides and other contami southeastof Salt Lake City. For more informationorreservations,call (800) 449-2288,or visit www.visitmesaverde.com. care,living wills, care of the homebound, community resources and Medicare. The classes are free, but there is a $20 refundable book fee. Participants maytake the entire series of attend just the classes relevantto their situation. For more information,call Wendy Kellemsat(801) 373-7850 ext. 2451. Fs ; ‘Twolectureson | IN FOOD gazing at Mesa Verde National Park in southwestern Colorado on June11 and 12. Costof the outingis $79 per person, whichincludes a guided tour ' FYI PESTICIDES Hansen Planetarium will present a weekend of sky programs and star- South. The classes + be taught by Am Brockemeyer, physi therapist at Cotton wood Hospital Back nants they consume ona daily basis and thepotential health effects. The site ana lyzes food choices based on more than 90,000 government stitute, who suggest they be takenas ase laboratorytests for food con. taminants. bom at the center ries. For more infor tion, call Penny Wal TheSalt LakeTribune HEALTH & SCIENCE 7 LYNN ZARITSKY, B-2 MANN LANDERS, B-3. BECOMICS, B-4 MITELEVISION, B-S B THURSDAY M WEATHER, B-6 JUNE 3, 1999 Putting physics to work perinieeSeernate haisof s a those sharp, turns in bl thebballerina eee to rotate at two and the prroucne Koehler seems unfettered by such phys straints as inertia andgravity. She pirouettes into whirling spins, performs leaps that appear to suspend herin midair, andlofts sky ward with just the slightest lift from a partner. Now, after working witha physicist, she has mastered the lawsof nature she appearsto defy, and she uses her knowledgeof forces, work, velocities and angular momentumto enhancetheillusion. Herteacher in the physics of dance is Ken Laws, a professor at Dickinson College in Carlisle, Pa. Recently, he joined Koehler to demonstrate this merg: ingofart and sciencefor the annual meetingof the American Physical Society in Atlanta. Like magicians, he says, ballet dancers create an illusion based not only on their physical skills but also on the ways they take advantage of laws of motion. “Understanding these principles really helped me as a dancer,” says Koehler, whois with the Chicagobased BoitsovClassical Ballet. “My turns havereally improved.” At a demonstration at Atlanta’s Fox Theatre, the pair deconstruct several moves that will be performed later by the Atlanta Ballet. In the tour jeté, Koehlerleaps up andturns 180 degrees in midair—-or so it appears — before returning to earth. But basic physics says you can’t rotate in the air without pushingoff something. Looking at the moveonstage, Laws tells a group made up largely of physicists, “you might think, ‘That's beautiful,’ or you might think, "That violates the conservation of angular momentum.’ ” Forthose who haveforgotten high-schoolphysics, conservation of angular momentum is what keeps spinning objects going like a spinning ice skater or a well-thrown football. Technically, angular momentumis calculated as the speed of an object's rotation multiplied by its mo ment of inertia, which is a quantity related to the shape of an object. Havinglots of bulk far from your spin axis gives you a higher moment ofinertia. To keep the total angular momentum the same as the conservation law decrees whenan object's moment ofinertia goes up, its rotational speed goes down. Conversely, when an object’s inertia goes down, it rotates faster. Skaters use this principle whenthey pull their armsin close as they go into a spin. Doing that decreases their moment ofinertia, thereby speeding up therotation. The same principle h ps Koehler appearto turn in midair in the tour jeté. She doesn’t really start her turnin midair shestarts it when onefootis still on thefloor, pivoting to give her body a torquethat ro- tates her the opposite way.(Recall Newton’s law that 1 | The dancer extends her leg | away from the axis of rotation. | increases, slowing BY FAYE FLAM | her spin, 1 pe —u 1 As she 1 pulls her leg toward her | in ae 2” ly, her | moment of 1 inertia 1 1 ! 1 every action has an equalandoppositereaction.) Her rotation begins so slowly as to be imperceptible. She leaps into a position that gives her a high momentofinertia, with oneleg in front and one behind. But when she decreases that quantity by bringing her legs together and raising her arms overhead, shestarts to whip aroundfast. “She has a nice, compactaxisofrotation, and her body goes around quickly,” Laws says. Then, bringing her arms out again and moving oneleg behind her, she slows the turn before landing. Laws, 64, used to study solid-state physics, but switched to the study of the physics of dance 23 years ago, when,in his early 40s, he began to danceballui himself. It started with his young daughter’s ballet lessons. “Herlittle brother didn’t wanttobe left out,”hesaid, so Laws’sonstarted dancing,too.“I didn’t wantto be left out either,” he said. Both children quit dance for other interests, but their father kept it up. He has taught physics to ballet classes aroundthe country, including his local company, the Cextral Pennsylva- Creating anillusion In this sequence from the Black Swanpas de deux, the ballerina playingthe role of Odile 4 Be twotricks of physics to work as she t leaps away from Prince Siegiried. By moving her armsand legsin various ways, she | i redistributes her mass horizontally to affect herrate of spin, and also vertically to adjust } hercenter ofgravity. nia YouthBallet, where healso studies dance. During the physics meeting, Laws acknowledges hat somepeople express skepticism. Some balletaficionadossay, “Don't analyze this for meor it will destroy the aesthetic appeal.” Some scientists accuse him of being frivolous. But he argues that his work canhelp people appreciate both art andscience. (@) In his demonstration, Laws shows how Koehler makesherleaps appear to hover for a split second, “like Michael Jordan.” During that gravity-defying moment her center of gravityis,in fact,still rising fromherinitial push off the floor. The trajectory of her center of gravity is determined when she leaves the floor, just the way thetrajectory of a baseball is determined by the way it is thrown. But by changingthe configuration of her body, she can appear to float while her center of gravity is still actually rising. She doesthis bylifting herlegs ever higher into an airborne split at the top of herjump. Laws also demonstrates the way angular momentum comes into play in a movecalled the “whip turn.” Koehlerbegins the whip turn balanced ononetoe, her otherleg extended straight out before her. Laws gives herthe slightest nudge, sending herintoa pir. Boek aAP The ballerina starts her spin by applyingtorque, ortwist, to the ground as she pusheso! Sheextends her leg and springs off the ground The extendedleg slows her rateof spin Thenshesettles tothefloor in a pose called an | arabesque | Once airborne,the ballerina drawsher leg in Finally, the dancer drops smoothly from the increases; she “snaps” around arabesque into a deep, swan-like bow. The Controlled flow of this finish enhances the gravity: defying appearance ofthe entire movement toward her centerof rotation. Her rate of spin ouette offive full rotations as she pulls her leg back Sce PHYSICS,Page B-6 SOURCES: Ballet Steps: Practice to Performance by Anthony Dutort, American Ballet Theater, BailotWeb (www.novia.nel/-jiw/indax him!) Graph nr Guide to Address 90s Concerns More ‘Miracle’ Margarine! long, strange trip it has been. When Olds wrote 7'he Complete Guide to Breastfeeding in 1972, breastfeeding was at its lowest point in U.S. history, Only 1 in 4 women nursed. Forfive decades, fromthe 1920s to the 1970s, American women embraced baby formula as the best way to feed their championed formula babies. Doctors because they were convinced that formula was as good as or better than breast milk; women liked formula because it “emancipated” themfrom staying home with the baby or hiring a wet nurse, Formula was seen, says Olds, as the modern, civilized waytofeed an infant Today, morethan 25 yearsafter Olds wrote that book, times have changed. Medical researchers havediscovered numerous health benefits associated with copy } breastfeeding. Mother's milk, they've learned, provides babies with protective antibodies that ward off illness. They have discoveredthat breast milk contains a fatty acid vital for eye and brain development; and breastfeeding even seems to have a positive effect on cholesterol levels later in life. So, armed with a load of new scientific developments and lot of questions from another genera: tion of young women, Olds went back to the computer to work on. the third edition of The Complete Bookof Breastfeeding (Workman, $10.95). In it she answers many ofthe questions asked by today's young women, such as whether they can nurseif they have hadtheirnip: ples pierced(yes, but check with a lactation specialist); if nursing protects themfrom breast cancer (it does reduce your risk of getting breast cancer); and if nursing will affect their figures (yes, breastfeeding momslose 1.5 pounds a month). But for Olds and other breast feeding advocates, the newsisn't al togetherpositive. Today, 60 percent of new mothers breastfeed their ba bies up from25 percent in 1972 but that rate falls far short of the projections made a decade ago by the U.S. Surgeon General's office. Back in 1990, the Surgeon General's staff set a goal of 75 percent of Am rican women to nurse their ba yy the year 2000. “Asa society, we need to make changes in the workplace so that new mothersfeel they can pumpor express their milk while they're at work,” Oldssaid. “Weneed to make women feel comfortable about breastfeeding in public in some states, women haveactually been arrested for breastfeeding in public.” But oneofthegreatest challenges is to get accurate breastfeeding See BREASTFEEDING,Page B-6 | Theballerina extends herotherleg to slow her rotation. This also pushes her center ofgravity up on her body, making her appearto “float” Lower Your Cholesterol — Eat BY LINDA SHRIEVES } i decreases and she spins faster. Author Updates Breastfeeding KNIGH- RIDDER NEWS ERVICE For Sally Wendkos Olds, what a | — the ballerina is changing her moment of inert ia. She warescall redistributetes the mass BuroUndig the axis of her spin the same way figure skaters do. 1 [etircsnent3inertia KNIGHT RIDDER NE RVICI Onceshesteps into hertoe shoes, balleri } im rotation | : BY GWEN SCHOI SACRAMENTO BEE Maybeyousawthe tabloid headline but were too embarrassedtopeek inside: “Miracle marga rine zaps cholesterol; 100 million Americans will benefit.” Well, wescoopedit up so you won't have to. This “miracle margarine” story happens to have some truthto it, The National Examiner fo cused on Take Control, made by Lipton. Take Control and a similar product called Benecol, from McNeil Consumer Healthcare, are cholesterol-lowering products described as func: tional foods, which are foods with added nutri ents or plant components that are supposed to promotehealth or prevent disease Benecol contains stanol esters, which are plant components madefromwood-pulp extract. Take Control contains sterol esters, which are plant constituents made from soybean oil extract ‘Theplant components, which are not absorbed by the body, reduce cholesterol levels in humar by inhibiting cholesterol absorption in the di tivetract, scientists say Aretheysafe? According to the FDA, studies show they are. The FDA has approved both prod: ucts for distribution. “The FDAis not aware of anyscientific ev dence that plant stanol esters would be harmful. said Alan Rulis of the FDA's Center for Food Safety and Applied Nutrition he Center for Science in the Public Interest ii Washington, D.C., a nonprofit consumer healt! group, has been watching the development of functional foods, specifically cholesterol lowering margarine substitutes, for several years. The group's view is that these two new products aresafe and do work “There are really two issues that concern us: whether they work and theprocess by whichthey wereapproved by the FDA,” said David Schardt associate nutritionist with the CSPL “The ingre dientsin these margarine substitutes are a family of compounds which we normallyfind in ou foods, but at a lowerlevel. It is c that these ingredients do lower cholesterol. What manufac turers have doneis concentrate theseingredients to make them more effective. son to think they are unsafe.” There is no rea Schardt called the compounds “an effective tool in managing cholesterol.” But, he said “consumers need to keep in mind that studies were done using these products in conjunction See MARGARINE,Page B-6 | |