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排序方式: 共有1706条查询结果,搜索用时 15 毫秒
1.
William E. Cooper Jr. Christopher S. Deperno Johnny Arnett 《Journal of chemical ecology》1994,20(11):2867-2881
Experimental tests showed that poststrike elevation in tongue-flicking rate (PETF) and strike-induced chemosensory searching (SICS) in the gila monster last longer than reported for any other lizard. Based on analysis of numbers of tongue-flicks emitted in 5-min intervals, significant PETF was detected in all intervals up to and including minutes 41–45. Using 10-min intervals, PETF lasted though minutes 46–55. Two of eight individuals continued tongue-flicking throughout the 60 min after biting prey, whereas all individuals ceased tongue-flicking in a control condition after minute 35. The apparent presence of PETF lasting at least an hour in some individuals suggests that there may be important individual differences in duration of PETF. PETF and/or SICS are present in all families of autarchoglossan lizards studied except Cordylidae, the only family lacking linguallly mediated prey chemical discrimination. However, its duration is known to be greater than 2-min only in Helodermatidae and Varanidae, the living representatives of Varanoidea. That prolonged PETF and SICS are typical of snakes provides another character supporting a possible a varanoid ancestry for Serpentes. Analysis of 1-min intervals showed that PETF occurred in the first minute. A review of the literature suggests that a pause in tongue-flicking and delay of searching movements are absent in lizards and the few nonvenomous colubrid snakes tested. The delayed onset of SICS may be a specific adaptation of some viperid snakes to allow potentially dangerous prey to be rendered harmless by venom following voluntary release after envenomation and preceding further physical contact with the prey. 相似文献
2.
A very simple algorithm for computing all k nearest neighbors in 2-D is presented. The method does not rely on complicated forms of tessellation, it only requires simple data binning for fast range searching. Its applications range from scattered data interpolation to reverse engineering. 相似文献
3.
一种有机化合物名称编码与亚结构检索方法 总被引:1,自引:0,他引:1
本文以 IUPAC 为基础,考虑有机化合物母体和取代基的关联,采用库中已有的化合物名称进行亚结构检索,这种检索方法,由于由化合物名称所劈裂的编码数量较少,所以索引文件小,检索速度较快。另外,这种方法是侧重在化学上有意义的母体和宫能团,它可以和碎片编码亚结构检索方法互相补充。 相似文献
4.
Parallel parsing is currently receiving attention but there is little discussion about the adaptation of sequential error handling techniques to these parallel algorithms. We describe a noncorrecting error handler implemented with a parallel LR substring parser. The parser used is a parallel version of Cormack's LR substring parser. The applicability of noncorrecting error handling for parallel parsing is discussed. The error information provided for a standard set of 118 erroneous Pascal programs is analysed. The programs are run on the sequential LR substring parser. 相似文献
5.
超声波压力检测中回波搜索算法 总被引:2,自引:0,他引:2
通过对超声波压力测量中回波信号特征的分析,提出了回波自动搜索算法。该方法把快速傅立叶变换方法和小波多分辨率信号分解相结合,精确地检测出回波的包络信号,从而准确地搜索到回波,为后续的压力信号处理及提高压力测量的精度奠定了基础。 相似文献
6.
As a response to attack by herbivores, plants can emit a variety of volatile substances that attract natural enemies of these insect pests. Predators of the banana weevil, Cosmopolites sordidus (Germar) (Coleoptera: Curculionidae) such as Dactylosternum abdominale (Coleoptera: Hydrophilidae) and Pheidole megacephala (Hymenoptera: Formicidae), are normally found in association with weevil-infested rotten pseudostems and harvested stumps. We investigated whether these predators are attracted to such environments in response to volatiles produced by the host plant, by the weevil, or by the weevil–plant complex. We evaluated predator responses towards volatiles from banana pseudostem tissue (synomones) and the synthetic banana weevil aggregation pheromone Cosmolure+ in a two-choice olfactometer. The beetle D. abdominale was attracted to fermenting banana pseudostem tissue and Cosmolure+, whereas the ant P. megacephala was attracted only to fermented pseudostem tissue. Both predators were attracted to banana pseudostem tissue that had been damaged by weevil larvae irrespective of weevil presence. Adding pheromone did not enhance predator response to volatiles from pseudostem tissue fed on by weevils. The numbers of both predators recovered with pseudostem traps in the field from banana mats with a pheromone trap were similar to those in pseudostem traps at different distance ranges from the pheromone. Our study shows that the generalist predators D. abdominale and P. megacephala use volatiles from fermented banana pseudostem tissue as the major chemical cue when searching for prey. 相似文献
7.
结合高效的动态格点搜索(DLS)算法与扰动操作(Perturbation Operation)提出一种新的改进方法(DLS-PO),用于确定团簇的最低能量结构。针对一个特定构型,DLS算法总能给出其对应搜索空间的最规则结构。然而,一次失败的DLS优化将消耗大量的运算资源。为此,采取原子移动和结构旋转的扰动操作成功地改变了构型,再结合后续的DLS操作,提高了优化效率。将该算法用于原子数高达309的Lennard-Jones团簇及100原子NP-B函数铝团簇的结构优化。优化结果显示相比于DLS算法,DLS-PO算法更为高效。 相似文献
8.
9.
Walking tracks of Colorado potato beetles,Leptinotarsa decemlineata Say, were recorded on a locomotion-compensator in response to wind, odors of host plantsSolanum tuberosum L. and nonhost plantsLycopersicon hirsutum f.glabratum C.H. Mull, and to mixtures of these plant species. Host-plant odor induced positive anemotactic responses in starved females, whereas odor of the nonhostL. hirsutum was neither repellent nor attractive. The attractiveness of host-plant odor, however, was neutralized in the odor blend of plant species. Masking the attractive host-plant odor will hinder the beetle's searching for host-plant patches, and this principle may be exploited in pest control by mixed cropping.The locomotion-compensator was constructed with financial support from the Foundation for Fundamental Biological Research (BION), which is subsidized by the Netherlands Organization for the Advancement of Pure Research (ZWO), grant 14-02-02. The first author was supported by a grant from the French Ministry of Industry and Research. 相似文献
10.
Support vector machine forecasting method improved by chaotic particle swarm optimization and its application 总被引:2,自引:2,他引:0
By adopting the chaotic searching to improve the global searching performance of the particle swarm optimization (PSO), and
using the improved PSO to optimize the key parameters of the support vector machine (SVM) forecasting model, an improved SVM
model named CPSO-SVM model was proposed. The new model was applied to predicting the short term load, and the improved effect
of the new model was proved. The simulation results of the South China Power Market’s actual data show that the new method
can effectively improve the forecast accuracy by 2.23% and 3.87%, respectively, compared with the PSO-SVM and SVM methods.
Compared with that of the PSO-SVM and SVM methods, the time cost of the new model is only increased by 3.15 and 4.61 s, respectively,
which indicates that the CPSO-SVM model gains significant improved effects.
Foundation item: Project(70572090) supported by the National Natural Science Foundation of China 相似文献