The dynamics of social learning in an insect model,the bumblebee (<Emphasis Type="Italic">Bombus terrestris</Emphasis>)

Bumblebees (Bombus terrestris) are attracted to those particular inflorescences where other bees are already foraging, a process known as local enhancement. Here, we use a quantitative analysis of learning in a foraging task to illustrate that this attraction can lead bees to learn more quickly which flower species are rewarding if they forage in the company of experienced conspecifics. This effect can also be elicited by model bees, rather than live demonstrators. We also show that local enhancement in bumblebees most likely reflects a general attraction to conspecifics that is not limited to a foraging context. Based on the widespread occurrence of both local enhancement and associative learning in the invertebrates, we suggest that social influences on learning in this group may be more common than the current literature would suggest and that invertebrates may provide a useful model for understanding how learning processes based on social information evolve.     

Web数据挖掘技术在远程教育中的应用

使用Web数据挖掘技术发挥网络教育中资源共享以及无时间局限性的优势,达到帮助学习者快速有效地寻找满足其个性需求的教学资源的目的,并且对其学习进程进行准确指导.     

模糊神经网络用于环境大气质量评价的研究

研究了基于多准则学习的模糊神经网络评价环境大气质量的模型,并以此对某矿区的环境大气质量进行了评价,结果表明该方法简便、实用、客观。     

非物质经济——实现循环经济的关键

循环经济这一物质闭环流动型经济,是以“减量化、再利用、资源化”为原则,以物质闭路循环和能量梯次使用为特征,这一发展模式的关键其实就是非物质经济。循环经济给非物质化提出了新的技术上的挑战。本文所要探讨的是实现非物质化的主要途径。     

电除尘器在水泥厂烘干设备上的有效应用

针对水泥厂烘干机烟尘净化的电除尘设备存在的问题 ,提出了相应的解决措施 ,并例证了高压静电管式除尘器在烘干机除尘中的有效应用     

从实用结果评估污水除油用浮选机的分选能力

为从生产实际使用结果比较不同浮选机的分选能力 ,提出以小型浮选试验研究得到的除油结果做为比较时的一个基础数据 ,同时考虑处理量、浮选工艺条件、水的温度等因素的影响 ,还应注意其抗冲击能力。在讨论时应注意所用含油量分析方法     

混凝气浮—生物接触氧化法处理机械加工业含乳化油废水

在混凝剂筛选、不同水质处理效果比较和生物处理实验的基础上,优化确定出混凝气浮—生物接触氧化组合处理工艺。工程实践证实:将含油乳化液与总排口水混合,混凝气浮的COD去除率可达52.4%;接触氧化的COD去除率为81%;处理出水达到国家排放标准一级指标要求。     

Learning to predict channel stability using biogeomorphic features

Current human land use activities are altering many components of the river landscape, resulting in unstable channels. Instability may have serious negative consequences for water quality, aquatic and riparian habitat, and for river-related human infrastructure such as bridges and roads. Resource management agencies have developed rapid bioassessment surveys to help assess stability in a fast and cost-effective way. While this assessment can be done for a single site fairly rapidly, it is still time-consuming to apply over large watersheds and assessment activities must be prioritized. We constructed a system that employs commonly available map data as inputs to cost-sensitive variants of decision tree algorithms to predict the relative channel stability of different sites. In particular, we use bagged lazy option trees (LOTs) and bagged probability estimation trees (PETs) to identify all unstable channels while making the smallest number of errors of classifying stable channels as unstable, thereby minimizing cost and maximizing safety. We measured the performance of the classifiers using ROC curves and found that the PETs performed better than the LOTs in situations where the number of instances of the stable and unstable classes were relatively balanced, but the LOTs did better where unstable examples were relatively rare compared to stable, perhaps due to the LOTs’ ability to focus on individual examples.     

Does colour matter? The importance of colour in avoidance learning, memorability and generalisation

Aposematic species exploit the ability of predators to associate, for example, conspicuous colouration with the unprofitability of prey. We tested the importance of colour for avoidance learning, memory and generalisation in wild-caught great tits (Parus major). First, we determined the birds’ initial colour preferences for red, yellow, orange and grey artificial prey items. The birds showed some preferences, as they were more willing to eat grey prey as their first choice, but these were not strong preferences. We then trained birds to discriminate red, yellow or variable (red and yellow) signals from grey where colours signalled palatable and unpalatable food. In general, the birds learned the discrimination task equally well, irrespective of which colours signalled unpalatability, and subsequently remembered the distinction between previously palatable and previously unpalatable colours in the memorability test. We did not find strong evidence that variability in the signal affected learning or memory. Our results suggest that, in a task where birds must discriminate between palatable and unpalatable prey, it does not matter which specific colour signals unpalatability, although this might be context-dependent. To study whether training also affects responses to unconditioned stimuli, we included orange prey items in the memorability test. Although orange had been palatable in the initial preference test, the birds ate fewer orange prey items after they had been trained to avoid red, yellow or both colours (variable signal) as unpalatable prey, but did not change their preference when trained that these colourful signals were palatable. This indicates that generalisation occurred more readily after a negative experience than a positive experience, a situation that would potentially allow imperfect mimicry to occur.     

Homopteran chemical signatures reduce aggression of tending ants

Summary. Because generalist ants are aggressive towards foreign insects, the recognition of homopterans by tending ants is critical in ant/homopteran trophobiosis. Herein we report experimental evidence indicating that Argentine ant, Linepithema humile (Mayr) (Hymenoptera: Formicidae) learn to associate the production of honeydew with the chemical characteristics of homopteran cuticle, suppressing ant aggression and allowing the ants to tend homopterans. Although chemically-mediated associative learning is well understood in honeybee foraging, to our knowledge, it has not been reported before in ant/homopteran trophobiosis.