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radiation Intensity, Including ultraviolet light, and diurnal fluctuation In 
temperature. The biological variables of the environment include the diversity 
of INA* bacteria and other biological agents which continually arrive at and 
colonize leaf surfaces. The physical and biological variables cannot be 
precisely duplicated In a greenhouse or growth chamber and, therefore, their 
collective effect can only be determined by field testing. There Is no 
substitute for field tests, a time-honored method for testing the efficacy of 
living agents on plants. Such field tests are required to advance knowledge. 
Without such tests, the new technology cannot be used to protect plants from 
frost damage, precluding realization of the anticipated substantial economic 
benef i ts. 
The need for NIH review and approval or disapproval of this proposed field 
test is to assure that there is review at the national level of whether the 
test can be conducted safely with no significant risk to health or the 
envi ronment. 
4.0 Description of Proposed Action and Alternatives 
4.1 Proposed Action 
ror purposes of this Environmental Assessment, NIH proposes to reaffirm 
its June 1, 1983, approval for Ors. Steven Lindow and Nickolas Panopoulos of 
the University of California, Berkeley, to field test under specified 
conditions bacteria with in vitro generated deletions of all or part of the 
genes involved in ice nucleatlon. The prior action was based on the NIH 
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