Dinosaurs

Wild Cactus. Photos by George H. H. Huey, text by Rose Houk. New York: Artisan, 1996. $25. ISBN 1-885183-20-8. Reviewed by John W. McLure.

Exploring with the Microscope. Werner Nactigall. New York: Sterling Publishing Company, 1995. 160 pp. $19.95 (hardcover). ISBN 0-8069-0066-1. Reviewed by Robert G. Hoehn.

The Encyclopedia of Snakes. Chris Mattison. New York: Facts On File, 1995. 256 pp. $35.00 (hardcover). ISBN 0-8160-3072-3. Reviewed by Carl Gans.

The Friendly Guide to the Universe. Nancy Hathaway. New York: Penguin, 1995. 462 pp. $13.95 (paperback). ISBN 0-14-015381-0. Reviewed by Lawrence A. Marschall.

One Small Square: Woods. Donald M. Silver, illustrations by Patricia J. Wynne. New York: W. H. Freeman and Company, 1995. 48 pp. $14.95 (hardcover). ISBN 0-7167-6610-8. Reviewed by Frances B. Spuler.

Naturalists, Conservationists, and Environmentalists. Eileen Lucas. New York: Facts On File, 1996. 150 pp. $16.95 (hardcover). ISBN 0-8160-2919-0. Reviewed by Clarence J. Murphy.

Astronomy for All Ages. Philip Harrington and Edward Pascuzzi. Old Saybrook, Conn.: Globe Pequot Press, 1994. 210 pp. $17.95 (paperback). ISBN 1-56440-388-2. Reviewed by Kristine Larsen.

Intermediate Science through Children's Literature. Carol M. Butzow and John W. Butzow. Englewood, Colo.: Teacher Ideas Press, 1994. 194 pp. ISBN 0-87287-946-1. Reviewed by Jacqueline V. Mallinson.     

Dynamic stability of a human standing on a balance board

The neuromuscular system used to stabilize upright posture in humans is a nonlinear dynamical system with time delays. The analysis of this system is important for improving balance and for early diagnosis of neuromuscular disease. In this work, we study the dynamic coupling between the neuromuscular system and a balance board—an unstable platform often used to improve balance in young athletes, and older or neurologically impaired patients. Using a simple inverted pendulum model of human posture on a balance board, we describe a surprisingly broad range of divergent and oscillatory CoP/CoM responses associated with instabilities of the upright equilibrium. The analysis predicts that a variety of sudden changes in the stability of upright postural equilibrium occurs with slow continuous deterioration in balance board stiffness, neuromuscular gain, and time delay associated with the changes in proprioceptive/vestibular/visual-neuromuscular feedback. The analysis also provides deeper insight into changes in the control of posture that enable stable upright posture on otherwise unstable platforms.     

Why Natural History Is Important to (Primate) Science: A Baboon Case Study

International Journal of Primatology - Natural history was the scientific approach used in early primate field studies and through the 1960s. After that, natural history fell out of favor,...     

Response of obligate heterozygotes for phytosterolemia to a low-fat diet and to a plant sterol ester dietary challenge

Twelve obligate heterozygotes from two kindreds were ascertained through phytosterolemic probands homozygous for molecular defects in the ATP binding cassette (ABC) half transporter, ABCG8. The response of these heterozygotes to a Step 1 diet low in fat, saturated fat, and cholesterol, and to 2.2 g daily of plant sterols (as esters) was determined in Protocol I (16 weeks) and Protocol II (28 weeks) during three consecutive feeding periods: Step 1/placebo spread; Step 1/plant sterol spread; and Step 1/placebo spread (washout). At baseline, half the heterozygotes had moderate dyslipidemia and one-third had mildly elevated campesterol and sitosterol levels. On the Step 1/placebo spread, mean LDL cholesterol decreased significantly, 11.2% in Protocol I (n = 12), and 16.0% in Protocol II (n = 7). Substitution with plant sterol spread produced a significant treatment effect on LDL levels in Protocols I and II. Conversely, the mean levels of campesterol and sitosterol increased 119% and 54%, respectively, during the use of plant sterol spread for 6 weeks in Protocol I, an effect mirrored for 12 weeks in Protocol II. During the placebo spread washouts, LDL levels increased, while those of plant sterols decreased to baseline levels in both protocols. In conclusion, phytosterolemic heterozygotes respond well to a Step 1 diet, and their response to a plant sterol ester challenge appears similar to that observed in normals.