inside front cover-19-2 EDITORIAL BOARD Editor in Chief Maricor N. Soriano, Ph.D. Associate Editors Zubaida U. Basiao, Ph.D. Biology Joel Joseph S. Marciano, Jr., Ph.D. Computer Science, Engineering Nemesio E. Montaño, Ph.D. Biochemistry Rosana Balangue-Tarriela, Ph.D. Earth Sciences (Geology) Fernando A. Siringan, Ph.D. Marine Sciences Cristine Villagonzalo, Ph.D. Physics Corazon D. Villareal, Ph.D. Managing Editor Dercylis G. Mararac Editorial Assistant SCIENCE DILIMAN (ISSN 0115-7809) is published bi-annually by the Research Dissemination and Utilization Office (RDUO) of the Office of the Vice Chancellor for Research and Development (OVCRD), University of the Philippines Diliman. Address all communications to the Editor in Chief, SCIENCE DILIMAN, Research Dissemination and Utilization Office, Office of the Vice Chancellor for Research and Development, Lower Ground Floor, Phivolcs Bldg., C. P. Garcia Ave., University of the Philippines, Diliman, Quezon City 1101 Philippines. Subscription Rates: P 300.00/year (two issues), inclusive of postage US $ 25.00/year (two issues), inclusive of postage Tel. No: (632) 981-85-00 loc. 4047 (632) 927-2567; 927-2309; 436-87-20 TelFax: (632) 927-2568 E-mail: rduo.ovcrd@up.edu.ph Website: http://www.ovcrd.upd.edu.ph SCIENCE DILIMAN A Journal of Pure and Applied Sciences TEOFILO A. ABRAJANO JR., Ph.D. Department of Earth and Environmental Sciences Rensselaer Polytechnic Institute Troy, New York abrajt@rpi.edu ALFONSO M. ALBANO, Ph.D. Department of Physics Bryn Mawr College Bryn Mawr, Pennsylvania aalbano@brynmawr.edu ANGEL C. ALCALA, Ph.D Angelo King Center for Research and Environmental Management Silliman University Dumaguete City, Philippines sumanila@psdn.org.ph; suakcrem@philwebinc.com FELIXBERTO A. BUOT, Ph.D. Naval Research Laboratory Washington, D.C. buot@estd.nrl.navy.mil; fab@cfdrc.com JOSEFINO C. COMISO, Ph.D. Laboratory for Hydrospheric Processes NASA Goddard Space Flight Center Greenbelt, Maryland comiso@joey.gsfc.nasa.gov LOURDES J. CRUZ, Ph.D. The Marine Science Institute University of the Philippines Diliman Quezon City, Philippines luly@upmsi.ph EDGARDO D. GOMEZ, Ph.D. The Marine Science Institute University of the Philippines Diliman Quezon City, Philippines edgomez@upmsi.ph PER JUEL HANSEN, Ph.D. Marine Biological Laboratory University of Copenhagen Helsingor, Denmark pjhansen@zi.ku.dk JORGEN HYLLEBERG, Ph.D. Department of Biological Sciences and Marine Ecology University of Aarhus Aarhus, Denmark hylleberg@biology.aau.dk CHRIS M. IRELAND, Ph.D. Department of Medicinal Chemistry University of Utah Salt Lake City, Utah cireland@deans.pharm.utah.edu INTERNATIONAL ADVISORY COMMITTEE EMIL Q. JAVIER, Ph. D. Institute of Plant Breeding University of the Philippines Los Baños College, Laguna, Philippines emil.javier@cgiar.org AMADOR MURIEL, Ph.D. Data Transport System New York, New York dtsny@msn.com BALDOMERO M. OLIVERA, Ph.D. Department of Biology University of Utah Salt Lake City, Utah olivera@biology.utah.edu EDUARDO A. PADLAN, Ph.D. Kensington, Maryland EdPadlan@aol.com WILLIAM G. PADOLINA, Ph.D. International Rice Research Institute College, Los Baños, Laguna w.padolina@cgiar.org KELVIN S. RODOLFO, Ph.D. Department of Earth and Environmental Sciences University of Illinois Chicago, Illinois krodolfo@uic.edu GARY E. RODRICK, Ph.D. Department of Food Science and Human Nutrition University of Florida Gainesville, Florida GERodrick@mail.ifas.ufl.edu FRANCIS J. SCHMITZ, Ph.D. Department of Chemistry and Biochemistry University of Oklahoma Norman, Oklahoma fjschmitz@chemdept.chem.ou.edu GAVINO C. TRONO JR., Ph.D. The Marine Science Institute University of the Philippines Diliman Quezon City, Philippines trono@upmsi.ph