旅游环境舒适度评价及其时空分异——以杭州西湖为例

旅游环境舒适度是影响旅游者出行决策和消费行为的重要因素,进一步影响到目的地适游期长短和旅游设施利用率。影响旅游舒适度的因素主要包括气候与环境两方面。以杭州西湖景区为研究对象,尝试将影响舒适度的空气质量、噪音等环境因素与气候因素共同纳入评价体系,选取温度、相对湿度、二氧化碳、一氧化碳、噪音5项指标和6个代表性检测点,进行为期1a定时定点检测,在排除二氧化碳与一氧化碳影响的基础上,构建了旅游环境舒适度评价模型,研究景区尺度存在的旅游环境舒适度时空分异特征。研究发现:不舒适时段主要集中在1月上旬到2月下旬,舒适和较舒适时段主要集中于2月下旬到7月中旬、8月下旬到11月下旬;山区与湖区各项环境指标要优于近城区、游客集聚区及交通繁忙区,平均舒适度山区(1.30)湖心区(1.66)城区(1.82)近城区(2.02)游人集聚区(2.47)交通繁忙区(2.48)。6个观测点在不同时段表现的舒适度差异也不同,差异最大的时段出现在4月中旬到5月中旬,差异最小时段出现在1月上旬到2月下旬。温湿度与噪音存在反向协同作用,引起环境舒适度变化。温湿度舒适时段往往旅游活动频繁,导致噪音升高降低了旅游环境舒适度。温湿度不舒适期旅游活动减少使得声环境相对舒适。     

噪音环境下花臭蛙求偶鸣声特征分析

2012年7月份,在黄山浮溪地区利用超声录音设备录制并分析了繁殖季节雄性花臭蛙(Odorrana schmackeri)个体的求偶鸣声。观察发现花臭蛙繁殖活动主要集中在7月中旬,繁殖高峰期活动无昼夜规律,全天均可见求偶鸣叫及抱对产卵等行为,并且多在浅水滩处活动。花臭蛙鸣声根据音节数和声谱特征可分为4种类型:即单音节音、婴儿音、双音节音和多音节断奏音,其中,单音节音、双音节音和婴儿音较为常见。利用Selena软件给出4种声音的语图以及各自对应的能谱图,利用Sound Analysis pro v1.2对单音节音、双音节音和婴儿音的鸣声特征参数进行定量分析,分析的声音参数包括鸣叫持续时间、音节数、音节持续时间、音节间隔、主频、脉冲率等。结果表明,花臭蛙鸣声的主频范围为1.8~4.5 k Hz(n=65)。鸣声不包括超声组分,主频峰值(3.1±0.7)k Hz,与前人电生理实验所得花臭蛙听觉敏感峰值一致,说明花臭蛙主要在这一频段进行通讯。对3种常见鸣叫音声音参数的单因素方差分析结果表明,双音节音与单音节音和婴儿音在声音持续时间上存在显著性差异(P0.01),双音节音和单音节音在第二谐波声强上也具有显著性差异(P=0.01)。花臭蛙的双音节音在3种常见鸣叫音中具有最长的持续时间,为(99.5±8.4)ms,故推测,双音节音为花臭蛙繁殖期主要求偶鸣声,并通过其鸣声时长的变化来体现自身品质的好坏。     

城市绿地的生态环境效应研究进展

工业化的快速发展和城市化进程的加剧,使得城市生态环境的破坏和污染愈来愈严重,加速了城市的“生态环境危机”.城市绿地能够通过植被的光合作用、吸收作用、隔离阻挡作用、蒸腾以及蒸散作用改善城市的生态环境.目前研究主要集中在降温、增湿、固碳释氧、降噪、抗污染、生物多样性保护等6个方面.关于城区绿地对6种生态环境要素的改善程度、影响范围、机理问题以及不同植被种类生态环境效应的差异情况等,国内外学者都进行了大量详细的研究.基于传统实地观测数据进行城市绿地的生态环境效应研究是目前主要使用的研究方法,部分学者开始使用遥感技术手段研究城区绿地的降温增湿效应.在总结和分析前人研究成果的基础上,从研究内容的不同着手,主要总结并系统评估了目前关于城市绿地6种生态环境效应的研究,为今后相关研究提供参考.     

生物钟体系中色噪音诱导的日夜节律振荡和内信号随机共振

利用脉孢菌生物钟体系,研究了色噪音对其进行诱导所产生的日夜节律振荡信号及其内信号随机共振的行为．结果表明,色噪音的相关时间对该体系内信号随机共振的强弱起较大的影响作用．当无外信号存在时,色噪音的相关时间对体系内信号随机共振强度起抑制的作用,且随相关时间的增大,抑制作用增强．当外信号加到体系中时,由于相关时间和外信号的协同作用,相关时间不仅对其内信号随机共振强度起抑制的作用,而且还影响内信号随机共振峰的数目,即随相关时间的增大,可使单峰随机共振变为随机双共振．存在最佳的外信号频率使体系的内信号随机共振强度得到最大的增强,而其他频率的外信号却起抑制作用．色内噪音和色外噪音相比,前者对该体系进行诱导所得的内信号随机共振强度比后者的更强,而且体系对前者更敏感．另外,存在极限的噪音强度使白噪音和色噪音对该体系内信号随机共振的影响差异得以消失．所得结果可为治疗生物钟紊乱综合症提供理论依据,同时可更好地理解其他节奏机理,如心脏搏动节奏、呼吸节奏以及荷尔蒙水平的波动节奏等．     

Effects of the egg incubation environment on turtle carapace development

Developing organisms are often exposed to fluctuating environments that destabilize tissue-scale processes and induce abnormal phenotypes. This might be common in species that lay eggs in the external environment and with little parental care, such as many reptiles. In turtles, morphological development has provided striking examples of abnormal phenotypic patterns, though the influence of the environment remains unclear. To this end, we compared fluctuating asymmetry, as a proxy for developmental instability, in turtle hatchlings incubated in controlled laboratory and unstable natural conditions. Wild and laboratory hatchlings featured similar proportions of supernumerary scales (scutes) on the dorsal shell (carapace). Such abnormal scutes likely elevated shape asymmetry, which was highest in natural nests. Moreover, we tested the hypothesis that hot and dry environments cause abnormal scute formation by subjecting eggs to a range of hydric and thermal laboratory incubation regimes. Shape asymmetry was similar in hatchlings incubated at five constant temperatures (26–30°C). A hot (30°C) and severely Dry substrate yielded smaller hatchlings but scutes were not overtly affected. Our study suggests that changing nest environments contribute to fluctuating asymmetry in egg-laying reptiles, while clarifying the conditions at which turtle shell development remains buffered from the external environment.     

Do neocortical pyramidal neurons display stochastic resonance?

Neocortical pyramidal neurons in vivo are subject to an intense synaptic background activity that has a significant impact on various electrophysiological properties and dendritic integration. Using detailed biophysical models of a morphologically reconstructed neocortical pyramidal neuron, in which synaptic background activity was simulated according to recent measurements in cat parietal cortex in vivo, we show that the responsiveness of the cell to additional periodic subthreshold stimuli can be significantly enhanced through mechanisms similar to stochastic resonance. We compare several paradigms leading to stochastic resonance-like behavior, such as varying the strength or the correlation in the background activity. A new type of resonance-like behavior was obtained when the correlation was varied, in which case the responsiveness is sensitive to the statistics rather than the strength of the noise. We suggest that this type of resonance may be relevant to information processing in the cerebral cortex.     

脑磁图神经活动源数目的估计

在脑磁图信号的分析中,正确估计出脑磁图神经活动源的数目是进一步分析脑磁图信号的前提。目前广泛采用的信息论方法和主成分分析方法都是根据特征值来确定源的数目,这两种方法在源数目较多、噪声较强的情况下,会导致误判。该文提出了一种噪声调节自动阈值的脑磁图源数目判断方法,利用基于噪声调节的主成分分析并结合聂曼- 皮尔逊准则对脑磁图源数目进行估计。同时,该方法采用了基于小波的噪声方差估计,实现了脑磁图信号中噪声方差的精确估计。通过对基于信息论方法、主成分分析方法以及该文所提议方法的实验结果的比较,表明该文所提议方法能更准确地估计脑磁图源数目,特别是在源数目较多、信噪比较小的情况下,仍能准确地估计脑磁图源数目,具有较大的实际意义。     

Mating interference of glassy‐winged sharpshooters,Homalodisca vitripennis

Animal communication is a complex behavior that is influenced by abiotic and biotic factors of the environment. Glassy‐winged sharpshooters (GWSS), Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), primarily use vibrational signaling for courtship communication. Because GWSS is a major pest, transmitting the plant pathogenic bacterium Xylella fastidiosa Wells et al., interruption of communication is a possible avenue for control. Playback of white noise, pre‐recorded female signals, and artificial female noise (continuously overlapping female signals) significantly reduced mating of GWSS when compared to silent control mating trials. Furthermore, to begin to determine the mechanism underlying playback control, female signaling activity was recorded in the presence of stimuli. In response to playback of female signals, females signaled (duet‐like) more often than females tested in the absence of playback. After the first playback, almost two‐thirds of females signaled a response within 3 s. Additionally, one‐third of the females signaled within 1 s after cessation of white noise, and significantly more in the time periods following noise termination. Results highlight how GWSS responds to differing competitive disturbances in the environment and lays important ground work that possibly could be used to develop pesticide‐free control methods.     

Color vision models: Some simulations,a general n‐dimensional model,and the colourvision R package

The development of color vision models has allowed the appraisal of color vision independent of the human experience. These models are now widely used in ecology and evolution studies. However, in common scenarios of color measurement, color vision models may generate spurious results. Here I present a guide to color vision modeling (Chittka (1992, Journal of Comparative Physiology A, 170, 545) color hexagon, Endler & Mielke (2005, Journal Of The Linnean Society, 86, 405) model, and the linear and log‐linear receptor noise limited models (Vorobyev & Osorio 1998, Proceedings of the Royal Society B, 265, 351; Vorobyev et al. 1998, Journal of Comparative Physiology A, 183, 621)) using a series of simulations, present a unified framework that extends and generalize current models, and provide an R package to facilitate the use of color vision models. When the specific requirements of each model are met, between‐model results are qualitatively and quantitatively similar. However, under many common scenarios of color measurements, models may generate spurious values. For instance, models that log‐transform data and use relative photoreceptor outputs are prone to generate spurious outputs when the stimulus photon catch is smaller than the background photon catch; and models may generate unrealistic predictions when the background is chromatic (e.g. leaf reflectance) and the stimulus is an achromatic low reflectance spectrum. Nonetheless, despite differences, all three models are founded on a similar set of assumptions. Based on that, I provide a new formulation that accommodates and extends models to any number of photoreceptor types, offers flexibility to build user‐defined models, and allows users to easily adjust chromaticity diagram sizes to account for changes when using different number of photoreceptors.