科创中国

Recursion?by?herbivores?is?the?repeated?use?of?the?same?site?or?plants.?Recursion?by?wild?animals?is?rarely?investigated?but?may?be?ubiquitous.?Optimal?foraging?theory?predicts?site?recursion?as?a?function?of?the?quality?of?the?site,?extent?of?its?last?use,?and?time?since?its?last?use?because?these?influence?site?resource?status?and?recovery.?We?used?GPS?collars,?behaviour?and?site?sampling?to?investigate?recursion?to?foraging?sites?for?two?elephant?Elephas?maximus?borneensis?herds?in?the?Lower?Kinabatangan?Wildlife?Sanctuary,?Borneo,?over?a?12?month?period.?Recursion?occurred?to?48?out?of?87?foraging?sites?and?was?most?common?within?48?hours?or?between?151-250?days,?indicating?two?different?types?ofrecursion.?Recursion?was?more?likely?to?occur?if?the?site?had?previously?been?occupied?for?longer.?Moreover,?the?time?spent?at?a?site?at?recursion?was?the?same?as?the?time?spent?at?the?site?on?the?first?occasion.?The?number?of?days?that?had?passed?between?the?first?visit?and?recursion?was?also?positively?correlated?with?how?much?time?was?spent?at?the?site?at?recursion.?Habitat?type?also?influenced?the?intensity?of?site-use,?with?more?time?spent?at?recursion?within?riverine/open?grass?areas?along?forest?margins?compared?to?other?habitat?types.?Recursion?is?a?common?behaviour?used?by?the?elephants?and?its?pattern?suggests?it?may?be?a?foraging?strategy?for?revisiting?areas?of?greater?value.?The?qualities?of?recursion?sites?might?usefully?be?incorporated?into?landscape?management?strategies?for?elephant?conservation?in?the?area?[Current?Zoology?60?(4):?551-559,?2014].

随着旅游市场竞争日趋激烈,目的地定位的重要性愈加突出.然而,国内研究和实践对"把握旅游者兴趣和需求"这一定位首要工作普遍认识不足,且实施不到位.鉴于此,本研究对目的地定位中"击中消费者心灵"这一关键环节的实施从理论和实证上进行了阐释.理论上,分析了目的地突出属性与定位之间的关系及当前国内误区.实证上,引入轮换方格分析法,以国内十大海滨城市目的地为要素,阐释了识别旅游者对竞争目的地相比较的目的地突出属性的方法程序.此外,对旅游者访谈结果与目的地业界代表访谈结果的比较发现,供需双方在旅游者需求的认识上不吻合.文章最后还对本研究的应用价值和局限做了总结.

为了研究地星上行和星地下行激光链路孔径内接收光强信号的典型特征,基于大气湍流理论和位相屏方法,计算了短波和中波红外激光在特定大气相干长度条件下,孔径内接收激光功率与总功率的比值及起伏情况。根据统计结果讨论了上下行大气通道传播特性的差异,结果表明相同外界条件下,直径50 cm孔径内接收的下行激光信号强度大于上行激光信号强度1个数量级以上,其信号的起伏程度也低于上行激光;中等湍流下,下行激光孔径接收光强的概率分布函数服从对数正态分布,最大概率接收功率比与无湍流条件下的功率比值一致,分别为0.42%(1.315μm )和0.26%(3.8μm )。

Lesser kestrels Falco naumanni are migratory central-place foragers that breed in dynamic arable landscapes. After arriving from migration, kestrels have no knowledge of the distribution of crops, and consequently prey, around their colony. The energy demand of pairs increases as breeding season progresses, but at the same time prey abundance, and their knowledge on prey distribution, also increases. Wind can have a strong influence on flight cost and kestrels should try to reduce energy expendi- ture when possible. When prey abundance is low, kestrels have little knowledge of prey distribution, and pairs have no chicks, they could reduce foraging flight cost by leaving the colony with tailwinds. When prey is abundant, knowledge on prey distribu- tion has increased, and chick demand is high, kestrels should fly to the most favorable foraging patches. We analyzed foraging trips directions in a lesser kestrel colony along the breeding season and in relation to wind speed and direction. We recorded 664 foraging trips from 19 individuals using GPS-dataloggers. We found that outward flights direction changed from uniform to a concentrated distribution along the season, as prey abundance and individual experience increased. We also found a temporal trend in the angular difference between outward flights and wind directions, with low values early in the season and then increa- sing as expected, but again low values at the end, contrary to expectation. Results suggest changes in kestrels foraging strategy along the season in relation to wind. Kestrels depart more with tailwinds in exploratory flights early in the season, while there is a spurious coincidence in direction to preferred foraging patches and dominant wind direction at the end [Current Zoology 60 (5): 604-615, 2014].

Because antipredator behaviours are costly, the threat-sensitive predator avoidance hypothesis predicts that individual animals should express predator-avoidance behaviour proportionally to the perceived threat posed by the predator. Here, we experimentally tested this hypothesis by providing wild passerine birds supplemental food (on a raised feeding platform) at either 1 or 4 m from the edge of forest cover (potential refuge), in either the presence or absence of a nearby simulated predation threat (a sharp-shinned hawk Accipiter striatus model). Compared with the control treatment, we observed proportionally fewer bird visits to the food patch, and the birds took longer to re-emerge from forest refuge and return to feed at the food patch, after the hawk presentation than before it. The observed threat-sensitive latency-to-return response was stronger when the food patch was further away from the nearest refuge. Overall, our results are consistent with the predictions of the threat-sensitive predator avoidance hypothesis in that wild passerine birds (primarily black-capped chickadees Poecile atricapillus) exhibited more intense antipre- dator behavioural responses with increasing level of apparent threat. The birds were thus sensitive to their local perceived threat of predation and traded-off safety from predation (by refuging) and foraging gains in open habitat in a graded, threat-sensitive manner [Current Zoology 60 (6): 719-728, 2014].

对landscape旅游景观的判读传统由来已久.文章对landscape同源异形的景观与地景两种译法进行了比较,区分了旅游景观与旅游地景的异同,并将旅游地景分为"成为的"旅游地景、"再造的"旅游地景和"创造的"旅游地景.选用地景主要是考虑对其原意的尊重、强调土地在中华文明中的重要地位及重视其传导的地方性信息.研究从有形的空间与无形的文化相交汇的视角来探讨旅游地景与地方的关联机理,认为空间视角下的旅游地景与地方是"依附中的割裂"关系,文化视角下的地方与旅游地景则呈现出"渗透下的不可控"的关系.研究提出了处理旅游地景与地方关系的理想模式,即由多方均衡参与的基础支持和内外融合的策略来实现神形兼备的目标的全方位一体化融入模式.

地裂缝严重制约了工农业生产、工程建设、城市规划和土地利用等发展国民经济的各项工作,是现今工程地震勘探的对象之一.文章首先介绍了隐伏地裂缝的特征、绕射波曲线特征和正演模拟理论,从理论上得出利用绕射波识别隐伏地裂缝的可行性;其次结合实例,从示范区地震时间剖面上识别出绕射波顶点,确定了隐伏地裂缝的位置和深度;最后得出结论,绕射波技术可作为隐伏地裂缝勘查的辅助手段.

目的:建立维地红涂剂中多糖的含量测定方法。方法用无水葡萄糖为对照品,0.2%蒽酮-硫酸试液为染色剂,紫外分光光度法测定,测定波长620 nm。结果多糖在1.9~34.2μg/ml范围内线性关系良好,Y=0.033X-0.0067(r=0.9999),回收率为98.6%,RSD=1.06%(n=6)。结论所建方法便捷、重现性好,适用于维地红涂剂中多糖的含量测定。