Ultrasonic communication in frogs

Among vertebrates, only microchiropteran bats, cetaceans and some rodents are known to produce and detect ultrasounds (frequencies greater than 20 kHz) for the purpose of communication and/or echolocation, suggesting that this capacity might be restricted to mammals. Amphibians, reptiles and most birds generally have limited hearing capacity, with the ability to detect and produce sounds below approximately 12 kHz. Here we report evidence of ultrasonic communication in an amphibian, the concave-eared torrent frog (Amolops tormotus) from Huangshan Hot Springs, China. Males of A. tormotus produce diverse bird-like melodic calls with pronounced frequency modulations that often contain spectral energy in the ultrasonic range. To determine whether A. tormotus communicates using ultrasound to avoid masking by the wideband background noise of local fast-flowing streams, or whether the ultrasound is simply a by-product of the sound-production mechanism, we conducted acoustic playback experiments in the frogs' natural habitat. We found that the audible as well as the ultrasonic components of an A. tormotus call can evoke male vocal responses. Electrophysiological recordings from the auditory midbrain confirmed the ultrasonic hearing capacity of these frogs and that of a sympatric species facing similar environmental constraints. This extraordinary upward extension into the ultrasonic range of both the harmonic content of the advertisement calls and the frog's hearing sensitivity is likely to have co-evolved in response to the intense, predominantly low-frequency ambient noise from local streams. Because amphibians are a distinct evolutionary lineage from microchiropterans and cetaceans (which have evolved ultrasonic hearing to minimize congestion in the frequency bands used for sound communication and to increase hunting efficacy in darkness), ultrasonic perception in these animals represents a new example of independent evolution.     

Chen-Mobius变换在图像处理应用中的GUI实现

GUI界面是Matlab软件中实现程序功能的一种方式,本文的目的是实现Chen-Mobius变换在图像处理应用中的GUI界面。Chen-Mobius变换方法已应用于图像处理的去噪、水印、传输及保密,具有许多优点。而其软硬件的实现显得尤为迫切。鉴于此,文章实现了该方法在图像去噪方面的GUI交互界面,同时对比均值去噪方法,说明其优越性,为今后此法的软硬件功能实现和广泛应用打好基础。     

Na3Sc2V3O12∶Fe3 ＋掺杂体系微观结构的理论研究

基于三角对称下3d5组态体系的完全能量矩阵,通过理论模拟实验的EPR参量,运用2个不同的参数值A4（这2个参数分别来自赤铁矿和钇铁石榴石的光谱）,研究了Na3Sc2V3O12石榴石晶体中的四面体三价铁中心的光谱和局域微观结构。计算结果与已有的实验值相吻合。     

教育机构品牌调研及广州学习型城市品牌建设

本文通过分析广州地区知名教育机构品牌形象调查结果,挖掘教育机构品牌建设的先进经验,提出广州学习型城市品牌建设与宣传推广的原则、建设步骤、宣传推广模式及运行机制。     

安徽省竞技体育后备人才培养现况及发展对策研究

鉴于竞技体育后备人才培养之于竞技体育发展重要意义,采用文献、调查与数理统计法对安徽省竞技体育后备人才现况、各市区项目布局与各技术等级运动员规模及针对性发展对策进行研究．研究结果表明：安徽省竞技体育后备人才建设和储备方面存在“夺标思想”严重、总体数量较少、项目布局不合理、成材率低等问题．并由此提出相应对策．     

Distributed link scheduling method with physical interference model in wireless multi-hop networks

To further increase the throughput of wireless multi-hop networks,a distributed scheduling method is proposed,which takes physical interference model into account.It is assumed that nodes in the network can perform physical carrier sensing,and the carrier sensing range can be set to different values.In the traditional carrier sensing mechanism,the carrier sensing range is computed under the protocol interference model,which is not accurate.Here the optimal carrier sensing range with physical interference model is achieved.Each sending node implements the distributed approach in three phases at each time slot,and all the concurrent transmissions are interference free.Good performance can be achieved under this scheduling approach.The approximation ratio of the distributed method to the optimal one is also proved.     

关于Theta函数平方的恒等式

文章通过运用经典椭圆函数极点理论,得到一些雅可比Theta函数等式．再应用这些等式得到一些有关Theta函数平方恒等式,一些著名的Theat函数平方关系的恒等式成为了他们的特殊情形．     

高校图书馆客户知识分类体系探讨

随着信息通信技术的应用,高校图书馆内产生了大量的与客户相关的知识,图书馆需要通过有效的客户知识管理提升与创新服务。基于建立客户知识分类体系的研究角度,可将客户知识分为关于客户的知识、从客户获得的知识及面向客户的知识。阐述了高校客户知识管理的对象与内涵,分析了高校客户知识管理分类体系,建立了高校客户知识管理模型。     

猕猴B病毒妒和gC合成基因重组杆状病毒质粒的构建

目的构建猕猴B病毒gB和gc合成基因的杆状病毒重组质粒（rBacmid）。方法根据本室已经合成的猕猴B病毒gB基因和gc基因,利用BamHI和XhoI特异性酶切,将其亚克隆于昆虫杆状病毒的pFastBacHTA转座载体。将该阳性转座载体转化到DHlobac感受态细胞,从中筛选出阳性重组细菌,并提取重组质粒。结果获得了重组质粒bacmid—gB和bacmid—gC。结论该研究为猕猴B病毒gB和gc蛋白在杆状病毒系统内的表达奠定了基础。