排序方式： 共有22条查询结果，搜索用时 140 毫秒
1.
Aartsma Yavanna Hao Yueyi Dicke Marcel van der Werf Wopke Poelman Erik H. Bianchi Felix J. J. A. 《Landscape Ecology》2020,35(4):907-919
Landscape Ecology - Tritrophic interactions may be affected by local factors and the broader landscape context. At small spatial scales, carnivorous enemies of herbivorous insects use... 相似文献
2.
3.
Durocher-Granger Léna Mfune Tibonge Musesha Monde Lowry Alyssa Reynolds Kathryn Buddie Alan Cafà Giovanni Offord Lisa Chipabika Gilson Dicke Marcel Kenis Marc 《Journal of pest science》2021,94(4):1133-1146
Journal of Pest Science - Invasive alien species have environmental, economic and social impacts, disproportionally threatening livelihood and food security of smallholder farmers in low- and... 相似文献
4.
Bender PL Currie DG Poultney SK Alley CO Dicke RH Wilkinson DT Eckhardt DH Faller JE Kaula WM Mulholland JD Plotkin HH Silverberg EC Williams JG 《Science (New York, N.Y.)》1973,182(4109):229-238
The lunar ranging measurements now being made at the McDonald Observatory have an accuracy of 1 nsec in round-trip travel time. This corresponds to 15 cm in the one-way distance. The use of lasers with pulse-lengths of less than 1 nsec is expected to give an accuracy of 2 to 3 cm in the next few years. A new station is under construction in Hawaii, and additional stations in other countries are either in operation or under development. It is hoped that these stations will form the basis for a worldwide network to determine polar motion and earth rotation on a regular basis, and will assist in providing information about movement of the tectonic plates making up the earth's surface. Several mobile lunar ranging stations with telescopes having diameters of 1.0 m or less could, in the future, greatly extend the information obtainable about motions within and between the tectonic plates. The data obtained so far by the McDonald Observatory have been used to generate a new lunar ephemeris based on direct numerical integration of the equations of motion for the moon and planets. With this ephemeris, the range to the three Apollo retro-reflectors can be fit to an accuracy of 5 m by adjusting the differences in moments of inertia of the moon about its principal axes, the selenocentric coordinates of the reflectors, and the McDonald longitude. The accuracy of fitting the results is limited currently by errors of the order of an arc second in the angular orientation of the moon, as derived from the best available theory of how the moon rotates in response to the torques acting on it. Both a new calculation of the moon's orientation as a function of time based on direct numerical integration of the torque equations and a new analytic theory of the moon's orientation are expected to be available soon, and to improve considerably the accuracy of fitting the data. The accuracy already achieved routinely in lunar laser ranging represents a hundredfold improvement over any previously available knowledge of the distance to points on the lunar surface. Already, extremely complex structure has been observed in the lunar rotation and significant improvement has been achieved in our knowledge of lunar orbit. The selenocentric coordinates of the retroreflectors give improved reference points for use in lunar mapping, and new information on the lunar mass distribution has been obtained. Beyond the applications discussed in this article, however, the history of science shows many cases of previously unknown, phenomena discovered as a consequence of major improvements in the accuracy of measurements. It will be interesting to see whether this once again proves the case as we acquire an extended series of lunar distance observations with decimetric and then centimetric accuracy. 相似文献
5.
Kappers IF Aharoni A van Herpen TW Luckerhoff LL Dicke M Bouwmeester HJ 《Science (New York, N.Y.)》2005,309(5743):2070-2072
Herbivore-damaged plants release complex mixtures of volatiles that attract natural enemies of the herbivore. To study the relevance of individual components of these mixtures for predator attraction, we manipulated herbivory-induced volatiles through genetic engineering. Metabolic engineering of terpenoids, which dominate the composition of many induced plant volatile bouquets, holds particular promise. By switching the subcellular localization of the introduced sesquiterpene synthase to the mitochondria, we obtained transgenic Arabidopsis thaliana plants emitting two new isoprenoids. These altered plants attracted carnivorous predatory mites (Phytoseiulus persimilis) that aid the plants' defense mechanisms. 相似文献
6.
An experiment performed on a differentially rotating, density-stratified fluid shows that "spin-down" need not occur under the condition of stratification. Inasmuch as density stratification occurs in the interior of the sun, spin-down probably does not exist in the solar interior, and the observed solar oblateness may indicate that the sun contains a rapidly spinning core. 相似文献
7.
8.
An on-farm approach to quantify yield variation and to derive decision rules for site-specific weed management 总被引：2，自引：1，他引：1
C. Ritter D. Dicke M. Weis H. Oebel H. P. Piepho A. Büchse R. Gerhards 《Precision Agriculture》2008,9(3):133-146
Grain yield often varies within agricultural fields as a result of the variation in soil characteristics, competition from
weeds, management practices and their causal interactions. To implement appropriate management decisions, yield variability
needs to be explained and quantified. A new experimental design was established and tested in a field experiment to detect
yield variation in relation to the variation in soil quality, the heterogeneity of weed distribution and weed control within
a field. Weed seedling distribution and density, apparent soil electrical conductivity (ECa) and grain yield were recorded and mapped in a 3.5 ha winter wheat field during 2005 and 2006. A linear mixed model with
an anisotropic spatial correlation structure was used to estimate the effect of soil characteristics, weed competition and
herbicide treatment on crop yield. The results showed that all properties had a strong effect on grain yield. By adding herbicide
costs and current grain price into the model, thresholds of weed density were derived for site-specific weed control. This
experimental approach enables the variation of yield within agricultural fields to be explained, and an understanding of the
effects on yield of the factors that affect it and their causal interactions to be gained. The approach can be applied to
improve decision algorithms for the patch spraying of weeds. 相似文献
9.
Genetic engineering of plant volatile terpenoids: effects on a herbivore,a predator and a parasitoid
Martine Kos Benyamin Houshyani Aart‐Jan Overeem Harro J Bouwmeester Berhane T Weldegergis Joop JA van Loon Marcel Dicke Louise EM Vet 《Pest management science》2013,69(2):302-311
BACKGROUND: Most insect‐resistant transgenic crops employ toxins to control pests. A novel approach is to enhance the effectiveness of natural enemies by genetic engineering of the biosynthesis of volatile organic compounds (VOCs). Before the commercialisation of such transgenic plants can be pursued, detailed fundamental studies of their effects on herbivores and their natural enemies are necessary. The linalool/nerolidol synthase gene FaNES1 was constitutively expressed from strawberry in three Arabidopsis thaliana accessions, and the behaviour of the aphid Brevicoryne brassicae L., the parasitoid Diaeretiella rapae McIntosh and the predator Episyrphus balteatus de Geer was studied. RESULTS: Transgenic FaNES1‐expressing plants emitted (E)‐nerolidol and larger amounts of (E)‐DMNT and linalool. Brevicoryne brassicae was repelled by the transgenic lines of two of the accessions, whereas its performance was not affected. Diaeretiella rapae preferred aphid‐infested transgenic plants over aphid‐infested wild‐type plants for two of the accessions. In contrast, female E. balteatus predators did not differentiate between aphid‐infested transgenic or wild‐type plants. CONCLUSION: The results indicate that the genetic engineering of plants to modify their emission of VOCs holds considerable promise for facilitating biological control of herbivores. Validation for crop plants is a necessary next step to assess the usefulness of modified volatile emission in integrated pest management. Copyright © 2012 Society of Chemical Industry 相似文献
10.