Sensory complementation and the acquisition of predator recognition by salmonid fishes

Following disturbance, some aquatic prey species release chemicals that act as a warning cue and increase vigilance in nearby conspecifics. Such disturbance cues evoke consistent low intensity anti-predator responses. In contrast, alarm cues from injured conspecifics often evoke stronger intensity responses in prey animals. In this study, we test the sensory complement hypothesis, which suggests that multiple cues act in an additive or synergistic fashion to provide additional information for risk assessment by prey. In the first experiment, we showed that juvenile rainbow trout pre-exposed to disturbance cues respond to a given concentration of damage-released alarm cues with a higher intensity of response than the trout that were pre-exposed to cues from undisturbed conspecifics. The two cues acted in an additive fashion. In the second experiment, we demonstrated that disturbance cues alone were not enough to elicit a conditioned response to the odour of a novel predator. We also showed that while disturbance cues elicit an increase in the response of trout to alarm cues, this increase does not translate into a stronger learned response to the predator when the predator odour is paired with alarm cues. Future studies should take into account sensory complementation to avoid underestimating the responses of prey to predators.     

改进属性识别模型及其在城市环境质量综合评价中的应用

应用属性识别模型进行综合评价时,评价指标权重向量的计算具有一定的主观性。据此提出基于数据驱动技术的改进方法以使权重的确定更趋合理。实例说明,改进的属性识别模型不仅原理直观,评价结果准确,而且计算简便,在复杂系统综合评价中具有较广的适用性。     

旅游活动对滨海浴场水环境影响研究

基于灰色关联识别模型,从时空角度分析旅游活动对杭州湾北岸滨海人工浴场水环境的影响,研究滨海旅游活动与海水环境质量的关系。研究表明,滨海人工浴场由于管理模式及水体净化技术的不同,水域环境呈现不同的时空分布特征,但总体上滨海人工浴场建设和环境管理工作,可以有效保护滨海人工浴场以及周边区域水环境;不同旅游活动对水环境的影响程度不一,根据灰色关联识别模型综合评价指数,影响最大的是以水上自行车、皮划艇等为主的水上游乐项目,综合评价指数为2.571和2.542;其次是海滨游泳活动,综合评价指数为2.513;影响最小的水上舞台活动和观海踏潮,综合评价指数分别为2.501和2.472。     

地震前兆混沌时间序列多尺度分维异常识别研究

对地震前兆观测时间序列的混沌性态及其产生的根源进行了探讨。根据小波变换良好的时、频局部化特征和分形维数的变化特征,从小波分析多尺度分解的角度出发结合分形理论探讨了地震前兆混沌时间序列的异常识别问题。对几个实例的研究表明,大多数时间段内时间序列小波变换系数的分维—尺度变化曲线呈光滑、缓慢减小变化,有异常信息时段的时间序列小波变换系数的分维—尺度变化曲线变化的主要特点是曲线具有峰值,并出现了曲线先是由高向低,然后再由低向高变化,在某一尺度处达到峰值后再缓慢减小的情况。异常出现的时间在震前约2个月至1年。将小波变换与分形理论结合起来研究地震问题,不仅开拓了地震科学研究的新领域,同时也是对小波变换及分形理论应用的延拓。     

Threat-sensitive generalization of predator recognition by larval amphibians

Despite the importance of acquired predator recognition in mediating predator–prey interactions, we know little about the specific characteristics that prey use to distinguish predators from non-predators. Recent experiments with mammals and fish indicate that some prey lacking innate predator recognition have the ability to display anti-predator responses upon their first encounter with those predators if they are similar to predators that the prey has recently learned to recognize. This phenomenon is referred to as generalization of predator recognition. In this experiment, we documented for the first time that larval amphibians (woodfrog, Rana sylvatica) have the ability to generalize the recognition of known predators to closely related novel predators. Moreover, we demonstrated that this ability is dependent on the level of risk associated with the known predator. When red-bellied newt, Cynops pyrrhogaster (known predator), was paired with simulated low risk, tadpoles displayed fright responses to newts and novel tiger salamanders, Ambystoma tigrinum, but not to novel African clawed frogs, Xenopus laevis. However, when the newt was paired with simulated high risk, tadpoles generalized their responses to both tiger salamanders and African clawed frogs. Larval anurans seem to have a wider generalization frame than other animals.     

Two independent mechanisms of egg recognition in worker <Emphasis Type="Italic">Formica fusca</Emphasis> ants

Informational constraints can be an important limitation on the accuracy of recognition. One potential constraint is the use of recognition information from the same sources in multiple discriminatory contexts. Worker wood ants, Formica fusca, discriminate eggs based on their maternal sources of origin in two main contexts: recognition of eggs laid by nestmate versus non-nestmate queens and recognition of worker-laid versus queen-laid eggs. We manipulated the experience of F. fusca workers in laboratory colonies to both worker-laid and queen-laid eggs by transferring eggs between colonies in order to investigate whether these two contexts of egg discrimination are independent. Experience of non-nestmate queen-laid eggs significantly increased worker acceptance of both familiar (18% accepted) and unfamiliar (10%) queen-laid eggs compared to control workers without experience of eggs other than those laid by their own colony’s queen (2%). In contrast, worker acceptance of worker-laid eggs was not affected by variation in the egg experience of workers (14% in workers from control colonies exposed only to eggs from their own colony’s queen versus 19% and 17% in workers from colonies which had received eggs laid by either a non-nestmate queen or nestmate workers, respectively). Our results suggest that these two recognition contexts do not strongly constrain each other and are different in their ontogeny. In particular, worker-laid eggs are universally discriminated against by workers from colonies with a queen whatever the egg experience of the workers, while non-nestmate queen-laid eggs are strongly discriminated against only by workers without experience of eggs laid by more than one queen.     

Odour-based species recognition in two sympatric species of sac-winged bats (<Emphasis Type="Italic">Saccopteryx bilineata,S. leptura)</Emphasis>: combining chemical analyses,behavioural observations and odour preference tests

Combining chemical analysis and odour preference tests, we asked whether two closely related sympatric species of sac-winged bats use odour for species recognition. Males of the two sister species Saccopteryx bilineata and Saccopteryx leptura have pouches containing an odoriferous liquid in their antebrachial wing membrane, which is used in S. bilineata during courtship displays. Although both species occasionally share the same daytime roosts and are morphologically similar, there is no evidence for interbreeding. We compared the production and composition of the wing sac odorant in male S. leptura and S. bilineata and performed odour preference tests with female S. bilineata. Similar to male S. bilineata, male S. leptura cleansed and refilled their wing sacs with secretions, but they spent more time each day in doing so than male S. bilineata. Chemical analysis by gas chromatography and mass spectrometry revealed that male Saccopteryx carried species-specific scents in their wing sacs. Binary choice tests confirmed that female S. bilineata preferred the wing sac scents of male S. bilineata to those of the sister species, suggesting that the species specificity of male wing sac scents maintain the pre-mating isolation barrier between these closely related species.     

社会经济活动对太湖流域的生态影响分析

采用系统分析的方法,围绕社会经济压力、水体污染负荷以及水体环境状态3个方面,建立社会经济活动对太湖流域生态影响的评价指标体系,利用层次分析法计算各指标因子的权重.根据太湖流域2005和2006年的相关数据,以MATLAB为工具,运用模糊模式识别方法进行流域生态综合评价,分析社会经济活动对太湖流域的生态影响.研究结果表明,太湖流域的社会经济活动对湖泊生态的影响较大,除了点源污染以外,面源污染也是太湖流域生态环境问题的重要根源.     

企业自创商誉的确认与计量

按照传统的会计处理模式和惯例,无形资产中可以辨认的专利权、商标权已予确认和计量,而对于商誉,国内会计准则规定,只有在企业并购时,才作为一项无形资产确认入账,即只对外购商誉进行确认和计量,而不确认和计量自创商誉．在新的经济形势下,对于自创商誉应该有新的认识,就对自创商誉的确认和计量问题做出一些论述．参5．     

Ri质粒转化烟草的影响因素及豌豆凝集素基因在烟草发根中的表达

对Ri质粒转化烟草的影响因素进行研究,以期获得较为理想的实验系统,用发根农杆菌介导,将豌豆凝集素基因导入烟草,获得转基因的烟草发根,GUS组织化学染色,蛋白免疫原位杂交证明,gus报告基因和豌豆凝集素基因已在转基因烟草发根中得到了转译表达,本结构将为瘤菌能否扩大宿主范围,为研究烟草与豌豆根瘤菌相互作用,结瘤固氮的可能性奠定基础。