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News of the Week:
Added Noise Keeps Waves Going
Fluctuations in light intensity can enhance the propagation of chemical waves, suggesting noise as a mechanism for long-range signaling in brain tissue.
References:
Jung, P., et al. 1998. Noise-induced spiral waves in astrocyte syncytia show evidence of self-organized criticality. Journal of Neurophysiology 79(February).
Kádár, S., J. Wang, and K. Showalter. 1998. Noise-supported travelling waves in sub-excitable media. Nature 391(Feb. 19):770.
Further Readings:
Lipkin, R. 1996. Digital noise sharpens vague images. Science News 149(Mar. 30):196.
Peterson, I. 1991. The signal value of noise. Science News 139(Feb. 23):127.
Raloff, J. 1996. Is noise a neural necessity? Science News 150(Nov. 23):330.
Icy signs of warming emerge in Arctic
Satellite studies of sea ice provide evidence of Arctic warming.
References:
Smith, D.M. 1998. Recent increase in the length of the melt season of perennial Arctic sea ice. Geophysical Research Letters Feb. 15.
Further Readings:
Monastersky, R. 1997. Dead whales tell tales of sea ice decline. Science News 152(Sept. 6):148.
Radar illuminates ancient Cambodian site
Radar maps and archaeological field work provide new insights into an ancient civilization at Angkor.
References:
1998. NASA radar reveals hidden remains at ancient Angkor. NASA press release.
Further Readings:
Bower, B. 1998. Sacred secrets of the caves. Science News 153(Jan. 24):56.
Male sex hormone, preeclampsia link found
Elevated testosterone in women who once had preeclampsia, a complication of pregnancy, hints that the condition signals heart disease risk later in life.
References:
Laivuori, H. . . . O. Ylikorkala. 1998. Evidence of high circulating testosterone in women with prior preeclampsia. Journal of Clinical Endocrinology and Metabolism 83(February):344.
Further Readings:
Fontbonne, A., et al. 1991. Hyperinsulinemia as a predictor of coronary heart disease mortality in a healthy population: The Paris Prospective Study, 15-year follow-up. Diabetologia 34:356.
Laivuori, H., M.J. Tikkanen, and O. Ylikorkala. 1996. Hyperinsulinemia 17 years after preeclamptic first pregnancy. Journal of Clinical Endocrinology and Metabolism 81:2908.
Rare regeneration fixes pierced mouse ears
A lab glitch may yield a new—and rare—mammal model suitable for studying tissue regeneration.
References:
Heber-Katz, E., et al. 1998. The genetics of tissue repair and regeneration in mice. Annual meeting of the American Association for the Advancement of Science. Philadelphia.
Further Readings:
Heber-Katz, E. In press. The genetics of tissue repair and regeneration in mice. Clinical Immunology and Immunopathology.
Gamma-ray bursts: Farther and brighter?
The mysterious flashes of cosmic light known as gamma-ray bursts may be 20 times more energetic than previously estimated, and some may originate from the first galaxies born in the universe.
References:
Wijers, R.A.M.J., et al. 1997. Gamma-ray bursts from stellar remnants: Probing the Universe at high redshift. Monthly Notices of the Royal Astronomical Society Feb. 11.
Further Readings:
Cowen, R. 1997. Shedding light on a gamma-ray mystery. Science News 151(March 22):174.
Gene cloned for stretchiest spider silk
The extreme elasticity of so-called capture silk comes from long spirals in the protein's configuration.
References:
Hayashi, C.Y., and R.V. Lewis. 1998. Evidence from flagelliform silk cDNA for the structural basis of elasticity and modular nature of spider silks. Journal of Molecular Biology Feb. 6.
Further Readings:
Lipkin, R. 1996. Artificial spider silk. Science News 149(March 9):152.
Electromagnetic fields may trigger enzymes
Magnetic fields can set off a cascade of enzyme-driven cell-signaling events, which could lead to cancer.
References:
Dibirdik, I. . . . F.M. Uckun. 1998. Stimulation of Src family protein tyrosine kinases as a proximal and mandatory step for SYK kinase-dependent phospholipase C-gamma-2 activation in lymphoma B cells exposed to low energy electromagnetic fields. Journal of Biological Chemistry 273(Feb. 13):4035. Available online at http://www.jbc.org.
Kristupaitis, D. . . . F.M. Uckun. In press. Electromagnetic field-induced stimulation of Bruton’s tyrosine kinase (BTK). Journal of Biological Chemistry.
Further Readings:
Fackelmann, K.A. 1994. Do EMFs pose breast cancer risk? Science News 145(June 18):388.
Li, C., W. Lee, and R.S. Lin. 1998. Risk of leukemia in children living near high-voltage transmission lines. Journal of Occupational and Environmental Medicine February:144.
Linde, S. 1998. Statement at the EMF Review Symposium. Information is available at http://biomed.ucr.edu/Linde1.htm.
Raloff, J. 1998. EMFs’ biological influences. Science News 153(Jan. 10):29.
______. 1997. Magnetic fields can diminish drug action. Science News 152(Nov. 29):342.
______. 1993. EMFs run aground. Science News 144(Aug. 21):124.
______. 1993. EcoCancers. Science News 144(July 3):10.
______. 1990. EPA suspects ELF fields can cause cancer. Science News 137(June 30):404.
______. 1979. Electric-power lines linked with cancer. Science News 115(April 21):263.
Uckun, F.M. In press. Bruton’s tyrosine kinase (BTK) as a dual-function regulator of apoptosis. Biochemical Pharmacology.
Research Notes
Biology
Worms’ hot ends set thermal record
Worms living near hydrothermal vents keep cool heads whereas their rumps are immersed in water too hot for any other multicellular organism to endure.
References:
Cary, S.C., T. Shank, and J. Stein. 1998. Worms bask in extreme temperatures. Nature 391(Feb. 5):545.
Further Readings:
1992. Microbes to sup at Superfund sites. Science News 141(March 14):175.
Pennisi, E. 1994. Fastest (growing) worms in the world. Science News 146(Dec. 22):260.
Travis, J. 1997. A bacterium that munches on solvents. Science News 151(June 14):371.
Land hermit crabs spurn leftovers
Hermit crabs avoid eating food that smells like their last meal.
References:
Thacker, R.W. 1998. Avoidance of recently eaten foods by land hermit crabs, Coenobita compressus. Animal Behaviour 54(February).
Further Readings:
Edwards, D.D. 1988. Taking a crab’s eye view of the world. Science News 133(March 12):167.
Biomedicine
Stroke drug reveals a dark side
Studies in mice raise questions about the effectiveness of a clot-dissolving substance used to treat stroke.
References:
Del Zoppo, Gregory J. 1998. tPA: A neuron buster, too? Nature Medicine 4(February):148.
Wang, Y.F. . . . S.A. Lipton. 1998. Tissue plasminogen activator (tPA) increases neuronal damage after focal cerebral ischemia in wild-type and tPA-deficient mice. Nature Medicine 4(February):228.
Cancer treatment and memory loss
High doses of toxic chemotherapeutic drugs in tandem with tamoxifen may increase the risk of cognitive deficits in women being treated for breast cancer.
References:
van Dam, F.S.A.M., et al. 1998. Impairment of cognitive function in women receiving adjuvant treatment for high-risk breast cancer: High-dose versus standard-dose chemotherapy. Journal of the National Cancer Institute 90(Feb. 4):210.
Computers
Calculating a record prime
A college sophomore participating in the Great Internet Mersenne Prime Search has discovered the largest known prime number.
References:
Addtional information about the discovery of the 37th Mersenne prime is available at http://www.mersenne.org/3021377.htm.
Further Readings:
Peterson, I. 1997. Lucky choice turns up world-record prime. Science News 152(Sept. 13):164.
The announcement of the 38th Mersenne prime discovery contest can be found at http://www.entropia.com/ips/.
A history of the search for Mersenne primes is featured at http://www.utm.edu/research/primes/mersenne.shtml.
Overcoming quantum error
Accurate quantum computation is possible provided that the error per operation is below a threshold value.
References:
Knill, E., R. Laflamme, and W.H. Zurek. 1998. Resilient quantum computation. Science 279(Jan. 16):342.
Further Readings:
Peterson, I. 1996. Catching errors in scrambled quantum bits. Science News 149(Jan. 20):38.
______. 1995. Quantum bits. Science News 147(Jan. 14):30.
Environment
Forests as pollution filters
Forests are more likely to pull pollutant gases rather than particles out of the air.
References:
McLachlan, M.S., and M. Horstmann. 1998. Forests as filters of airborne organic pollutants: A model. Environmental Science & Technology 32(Feb. 1):413.
Bug sprays seem to really like toys
Pesticide foggers may leave residues that contaminate surfaces, especially plastic toys, for at least 1 week.
References:
Gurunathan, S. . . . P.J. Lioy. 1998. Accumulation of chlorpyrifos on residential surfaces and toys accessible to children. Environmental Health Perspectives 106(January):9.
Articles:
All Fired Up
Perception may dance to the beat of collective
neuronal rhythms
Synchronized activity in selected groups of brain cells apparently underlies perception and other cognitive functions.
References:
Crick, F., and C. Koch. 1998. Constraints on cortical and thalamic projections: The no-strong-loops hypothesis. Nature 391(Jan. 15):245.
Fries, P. . . . W. Singer. 1997. Synchronization of oscillatory responses in visual cortex correlates with perception in interocular rivalry. Proceedings of the National Academy of Sciences 94(Nov. 11):12699.
Revonsuo, A. In press. Is synchronization the direct neural correlate of visual awareness? NeuroReport.
Riehle, A., et al. 1997. Spike synchronization and rate modulation differentially involved in motor cortical function. Science 278(Dec. 12):1950.
Roelfsema, P.R. . . . W. Singer. 1997. Visuomotor integration is associated with zero time-lag synchronization among cortical areas. Nature 385(Jan. 9):157.
Stopfer, M. . . . G. Laurent. 1997. Impaired odour discrimination on desynchronization of odour-encoding neural assemblies. Nature 390(Nov. 6):70.
Further Readings:
Bower, B. 1996. Bridging the brain gap. Science News 150(Nov. 2):280.
Singer, W., and C.M. Gray. 1995. Visual feature integration and the temporal correlation hypothesis. Annual Reviews of Neuroscience 18:555.
Circles in the Sky
Detecting the shape of the universe
Evidence of a finite, multiply connected universe may show up in microwave data from future spacecraft.
References:
Cornish, N.J., D.N. Spergel, and G.D. Starkman. 1998. Measuring the topology of the universe. Proceedings of the National Academy of Sciences 95(Jan. 6):82.
Levin, J., E. Scannapieco, and J. Silk. Preprint. Is the universe infinite or is it just really big? Available at http://xxx.lanl.gov/abs/astro-ph/9802021.
Levin, J.J., et al. Preprint. Flat spots: Topological signatures of an open universe in COBE sky maps. Available at http://xxx.lanl.gov/abs/astro-ph/9702242.
Further Readings:
Bennett, C.L., M.S. Turner, and M. White. 1997. The cosmic Rosetta stone. Physics Today November:32.
Bond, J.R. 1998. Cosmic microwave background theory. Proceedings of the National Academy of Sciences 95(Jan. 6):35.
Cowen, R. 1998. Astronomers aglow about infrared maps. Science News 153(Jan. 10):20.
______. 1998. The cosmos' fate: World without end. Science News 153(Jan. 3):4.
______. 1997. From soup to us. Science News 151(June 7):354.
Thurston, W.P., and J.R. Weeks. 1984. The mathematics of three-dimensional manifolds. Scientific American July:108.
Weeks, J.R. 1985. The Shape of Space. New York: Marcel Dekker.
A synopsis of "The Shape of Space" video is available at http://www.geom.umn.edu/docs/forum/sos/ and http://www.geom.umn.edu/video/sos/.
Information about the SnapPea software developed by Jeff Weeks for visualizing and working with hyperbolic three-dimensional manifolds is at http://www.geom.umn.edu/software/download/snappea.html.
copyright 1998 Science Service
