Results 1 - 10 of 703
Results 1 - 10 of 703. Search took: 0.018 seconds
|Sort by: date | relevance|
[en] The sterile insect technique (SIT), which uses radiation to sexually sterilize insects and prevent reproduction, is particularly effective in eradicating harmful insects. The Joint Division of the IAEA/FAO has been involved in the use of isotopes and radiation in insect control since 1964. Efforts by the IAEA and FAO to transfer the SIT technology to developing countries are continuing by providing valuable research and development support for field projects. The cooperative SIT project against the tse tse fly was very successful in eradicating this harmful pest from the north-central Nigeria. A similar SIT project is actually underway to eradicate the Mediteranean fruit fly in Mexico
[en] Average life expectancy (ALE) is a significant integrating indicator of the population health. It can be affected by many factors such as radiation and hereditary ones. A population-genetic analysis of the average life expectancy (ALE) was performed for nuclear workers at the Mayak Production. Association exposed to external and internal radiation over a wide dose range and their offspring. A methodical approach was proposed to determine ALE for individuals with different genotypes and estimate ALE in the population based on genotype distribution. The analysis of a number of genetic markers revealed significant changes in the age-specific pattern of the Hp types in workers over 60 years. Such changes were caused by both radiation and non-radiation (cardiovascular pathology) factors. In the first case ALE decreased as Hp 1-1 > Hp 2-2> Hp2-1 (radiation). In the second case, it decreased as Hp 1-1> Hp-2-1> Hp2-2 (non-radiation). analysis of genetic markers in the workers offspring indicated significant shifts in distribution of the Hp types, especially an increase in the proportion of Hp 2-2 at doses from external γ-rays over 200 cGy to parents by the time of conception. Based on the non-radiation genotype differences in ALE in this group of offspring, the preliminary calculation of ALE was carried out, which indicated its reduction by 0.52 years in comparison with the control. (Author) 21 refs
[en] This new edition provides an up-to-date overview of methods and results of the application of mutation breeding in order to genetically improve vegetatively propagated crops. General principles and background information about mutation breeding in general, methods of treatment, material to be treated and results are discussed in the introductory chapters, followed by a description of the specific situation in each of the vegetatively propagated crops ever used in a mutation breeding treatment and plant material, such as aspects of mutagenic treatment, post-irradiation behaviour of shoot aspices and adventitious bud techniques. All available literature is then discussed crop by crop and critically evaluated. Almost 1700 references are covered and whenever possible suggestions for more efficient application of mutation breeding methods are given. 8 colour plates; 28 figs.; 48 tabs
[en] An impulsive SI model with Monod-Haldane functional response for pest control is proposed and investigated. First, we have proved that there exists an asymptotically stable pest-eradication periodic solution when the impulsive period is less than some critical value. Otherwise, the above system can be permanent. Then, influences of impulsive perturbation including impulse period, the time of spraying pesticide and the quantity of releasing infective pests on the above system have been studied. Moreover, numerical simulations show that the system has rich dynamical behaviors. Finally, it is concluded that the approach of combining impulsive infective releasing with impulsive pesticide spraying is more effective than the classical one if the chemical control is adopted rationally.
[en] The complexities of environmental interactions in the transport, transformation and biological effects of widespread, low level chemical contaminants confound the ability of current methods to predict the possible health and environmental impacts of both new and old chemicals. We cannot transfer with certainty the knowledge gained in the laboratory of the behaviour and effects of a single chemical study in isolated living species to that gained in a natural ecosystem. However, over the past years the environmental monitoring programmes have undergone rapid conceptual and technological advancement. Environmental monitoring plays an essential role in the evaluation and management of pesticides and other anthropogenic chemicals. In the absence of effective environmental monitoring, detection of serious environmental contamination and threats to human health caused by chemical pollutants may occur only after critical and irreversible damage has been done. Between 1976 and 1987 the ecosystematic effects caused by various herbicides and insecticides were analysed. The regenerative power of the tropical ecosystems, after having been treated with insecticides, does not only depend on the type of pesticide or its formulation and concentration, but also in a decisive way on the proportions of sprayed and unsprayed areas and the ecophysiological capacity of different organisms in the tropical food chains. (author). 19 refs, 4 figs, 6 tabs