the term “system” is defined as «elements standing interaction». this implies that a change in any given element should bring about changes in other elements of the system and thus may be used to identify the boundaries of a system. a system can be a machine, a man, or a community. each of these may be part of a greater system (super system) or include several smaller systems (subsystems). syst...

the first records of anopheles fluviatilis resistance to ddt was reported in 1963 from india and to dieldrin from eastern saudi arabia in 1959. in southern iran, antimalaria measures began in 1950 and up to 1957 the area was under ddt residual house spraying at the rate of 2g /m2 one round/year. during 1958-59 dieldrin was used at 0.5 g/m2, 1or 2 rounds/year was applied in the lowland areas. in...