A variable gain optical amplifier comprises an EDFA for amplifying optical signals at different wavelengths and a pump driver 14 for optically pumping the EDFA to provide optical gain. Compositions comprise novel nucleic acid sequences encoding a transcriptional activator involved in modulating gene expression in response to abiotic stress such as cold or drought. The nonvolatile storage device stores code and data which are handled by demand paging. The tube structure includes an expandable portion for enabling an increase in the cross-sectional area of the passage at the distal end. A handle cover is removably attachable about the handle post structure for enclosing the handle post structure during usage of the material dispenser structure. A high-level decision module receives the frame decision result and information based on the frequency estimation indications.