Content area
Full Text
news and views
flow in a cardiac system may serve both to increase mixing and to maintain organized spatial patterns. n Hassan Aref is in the Department of Theoretical and Applied Mechanics, University of Illinois at Urbana-Champaign, 104 South Wright Street, Urbana, Illinois 61801, USA.e-mail: [email protected]
1. Rothstein, D., Henry, E. & Gollub, J. P. Nature 401, 770772 (1999).
2. Aref, H. J. Fluid Mech. 143, 121 (1984).3. Arnold, V. I. C. R. Acad. Sci. A 261, 1720 (1965).4. Hnon, M. C. R. Acad. Sci. A 262, 312314 (1966).5. Eckart, C. J. Mar. Res. 7, 265275 (1948).6. Ottino, J. M. The Kinematics of Mixing (Cambridge Univ. Press, 1989).
7. Aref, H. & El Naschie, M. S. (eds) Chaos Applied to Fluid Mixing (Pergamon, Oxford, 1995).
Space biology
Life without gravity
Richard J. Wassersug
Now is a quiet period in space biology, perhaps as quiet as before autumn 1957, when Laika the dog and the
discipline left the launch pad. The primary platforms for biological research in microgravity are retired (Mir and NASAs modular Spacelab), on indefinite hold (Russias unmanned BION satellites), or still being made (the International Space Station). Even NASAs space shuttles are grounded for maintenance. So this is a good point at which to take stock of where space life science has been and where it might go. As part of this process, NASAs Center for Advanced Studies in the Space Life Sciences sponsored an unusual workshop last month* on how microgravity affects biological systems unusual in that it focused on microgravitys effects above the cellular level, in contrast to most contemporary biology, which is more molecular and reductionist in scope.
Research in space biology is often rationalized on the grounds that it may lead to medical advances for debilitating malaises of old age (such as osteoporosis and muscle wasting), or that it may improve the health and welfare of astronauts...