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Pesticide use in agriculture can cause undesirable effects on humans and the natural environment. One of the objectives of integrated agriculture is the elimination or reduction of possible sources of environmental pollution such as pesticides. To achieve this objective, farmers need a method to assist them in estimating the environmental impact of pesticide use. This paper addresses a two-part question: what factors should be taken into consideration to assess pesticide environmental impact, and how can impact be quantified? As the environmental impact of a pesticide depends on its dispersion in the environment and on its toxicological properties, the literature on these topics is reviewed to address the first part of the question. To address the second part of the question, six recent approaches to assess the impact of pesticides on the environment are compared regarding choice, transformation and aggregation of input parameters. The use of simulation models to assess environmental impact is discussed. 相似文献
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Yuen Tannirandorn Umberto Nicolini Peter C. Nicolaidis Nicholas M. Fisk Sabaratnam Arulkumaran Charles H. Rodeck 《黑龙江环境通报》1990,10(3):189-193
Twelve second-trimester fetuses with cystic hygroma underwent fetal blood sampling for rapid karyotyping, haematologic evaluation, and blood gas analysis. An abnormal karyotype was found in seven cases: monosomy X in five, trisomy 21 in one, and trisomy 13 in the other. Eight often fetuses undergoing blood gas analysis showed hypoxaemia, five of which were growth-retarded. Nine pregnancies were terminated. Of the remaining three, only one fetus survived the perinatal period. 相似文献
387.
The ubiquity of circadian rhythms suggests that they have an intrinsic adaptive value (Ouyang et al. 1998; Ronneberg and
Foster 1997). Some experiments have shown that organisms have enhanced longevity, development time or growth rates when maintained
in environments whose periodicity closely matches their endogenous period (Aschoff et al. 1971; Highkin and Hanson 1954; Hillman
1956; Pittendrigh and Minis 1972; Went 1960). So far there has been no experimental evidence to show that circadian rhythms
per se (i.e. periodicity itself, as opposed to phasing properties of a rhythm) confer a fitness advantage. We show that the
circadian eclosion rhythm persists in a population of the fruitfly Drosophila melanogaster maintained in constant conditions of light, temperature, and humidity for over 600 generations. The results suggest that
even in the absence of any environmental cycle there exists some intrinsic fitness value of circadian rhythms.
Received: 2 November 1998 / Accepted in revised form: 22 April 1999 相似文献
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We have determined the activity of alkaline phosphatase in chorionic villous tissue obtained in the first trimester of pregnancy, in order to obtain the normal range of values as a prerequisite for application to the prenatal diagnosis of the rare bone disease hypophosphatasia. The activities found were a combination of intestinal and liver/bone/kidney types; traces of placental type were present in only one sample. 相似文献
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