Some effects of diazinon on the microflora of submerged soils
SummaryThe application of diazinon, an organophosphorus insecticide, at the rate of 2 kg and 20 kg active ingredient per hectare to submerged Maahas clay significantly stimulated the actinomycete population. A distinct zone of brown pigmentation formed in that part of the profile commonly referred to as the oxidized layer. A profuse growth of actinomycetes developed from the soil samples of this pigmented zone when streaked onto the nutrient agar. A visible increase in algal populations was noted in the standing water of the diazinon-treated soil.
The distribution and persistence of diazinon applied to plant and soil and its influence on rhizosphere and soil microflora
Summary1. Evidence was obtained of the rapid translocation of radioactive Diazion through bean plants and its emergence in bean root exudates maintained under sterile conditions.2. The presence of bean rhizosphere microflora did not appear to be a factor in the metabolism of Diazinon by the bean plant.3. Diazinon applied at the rate of 3 lbs per acre to soil under non-sterile conditions persisted for as long as 180 days after application. No Diazinon was detectable after 10 weeks in soil receiving 0.3 lbs per acre.4. Diazinon or its degradation products exerted a selective effect common to both soil and rhizosphere microflora which expressed itself in the selective enrichment of a cocoidal rod. Numbers of fungi seemed unaffected by the presence of Diazinon. After 180 days a large number of the genus Streptomyces appeared as a seeming climax population.5. The predominant microbial isolate utilized Diazinon as a sulfur, phosphorus, carbon and nitrogen source in that order of preference. The biodegradability of Diazinon was conditioned by its solubilization in a suitable carrier, and by the presence of an additional carbon source.
What Happened to Suicide Bombings in Israel? Insights from a Terror Stock Model
An analysis of three years of suicide bombing data in Israel reveals an increase in such attacks through March 2002 followed by a steep decline through the end of 2003. The authors propose a terror-stock model that treats the suicide bombing attack rate as a function of the number of terrorists available to plan and execute suicide bombings. The intent of Israeli tactics such as targeted killings and preemptive arrests is to reduce the capacity of terror organizations to commit attacks. When fit to the data, this model suggests that the targeted killing of terror suspects sparks estimated recruitment to the terror stock that increases rather than decreases the rate of suicide bombings. Surprisingly, only the deaths of suspected terrorists, and not Palestinian civilians, are associated with such estimated recruitment. Although Israeli actions have reduced the rate of suicide bombings over time, it is preventive arrests rather than targeted killings that seem more responsible for this outcome.