Jul. 1, 2009 (United Press International) -- Climate change affects tornado activity ATHENS, Ga., July 1 (UPI) -- A U.S. study suggests the climate change effect of dry autumns and winters may lead to fewer tornadoes developing during the spring season.
University of Georgia researchers say global warming will likely mean more unpredictable weather conditions. They said their study indicates how drought conditions in an area's fall and winter may affect tornado activity the following spring.
The scientists said their study was specific to Georgia and the Southeastern United States, but further research could reveal patterns that might make the findings more general.
"Our results suggest that there is a statistically significant reduction in tornado activity during a tornado season following drought the preceding fall and winter," said Associate Professor Marshall Shepherd, a meteorologist and lead author of the study. "On the other hand, wet autumns and winters examined in the study had nearly twice as many spring tornado days as drought years did."
The researchers said they hope that one day meteorologists and climatologists might be able to predict the severity of a spring tornado season the way they now do for hurricanes.
The study that included Professor Thomas Mote, also of the University of Georgia, and Assistant Professor Dev Niyogi of Purdue University appears in the journal Environmental Research Letters.
Human trials sought for AIDS vaccine LONDON, Ontario, July 1 (UPI) -- Scientists said an HIV/AIDS vaccine developed at Canada's University of Western Ontario is ready for the first phase of human trials.
Officials at Sumagen Co. Ltd., the manufacturer of the vaccine, said they have submitted an investigational new drug application to the U.S. Food and Drug Administration to begin Phase 1 human trials for its SAV001-H AIDS vaccine.
The vaccine was developed by Professor Chil-Yong Kang who, with Sumagen, has completed safety and immunogenicity studies on animals.
University officials said Sumagen Canada has secured patents for the vaccine in more than 70 nations, including the United States, the European Union and Korea. According to the firm, animal testing has resulted in good antibody reactions in immunology tests, with no adverse effects or safety risks.
"The Phase l clinical trials, if approved, will double check the safety of the vaccine using HIV positive volunteers," the university said in a statement.
