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151.
《Marine Policy》2015
While there is considerable international research focused on the conservation outcomes of marine protected areas (MPAs) and marine reserves (MRs) there is little information on the economic cost to establish and manage these protected areas. This study estimated the MR pre-establishment and establishment costs for the Taputeranga Marine Reserve (TMR) in New Zealand (NZ) and determined the annual management costs for this reserve and four further NZ MRs. Finally, the cost to local rock lobster fishers resulting from the displaced fishing effort once the TMR had been established was estimated. This research found that the TMR pre-establishment cost was approximately NZ$508,000, and the establishment process cost was approximately NZ$353,000. The annual management costs across the five reserves ranged between NZ$43,200 and NZ$112,500 between 2008/09 and 2010/11. The annual fishers displacement cost at TMR was approximately NZ$22,000 per annum. This research showed that on a unit area basis, small MRs in NZ are just as expensive to maintain as large MRs. This study also highlighted how volunteer effort helped to considerably reduce the monetary cost of the MR pre-establishment process. This research increases our understanding of establishment and management costs, and supports future planning of MRs both within NZ and internationally. 相似文献
152.
作者于2013年5月至6月调查了位于江西北部地区岩溶地貌陆生贝类资源,共采得陆生贝类63种及亚种(含5个未定种),分别隶属于12科21属,其中1个新种,即石钟山弯螺(Sinoennea shizhongshanensis sp.nov),优势种为雪土鸥螺(Georissa niva)、细纹喇叭螺(Boysidia gracilis)、囊喇叭螺(Boysidia dorsata)和灰尖巴蜗牛(Bradybaena ravida ravida)。区系成分以东洋界成分为主,占总种类数的61.90%。计算了江西北部地区岩溶地貌陆生贝类多样性指数,其中Margalef丰富度指数(dMA)为2.205~4.273,Shannon-Wiener多样性指数(H′)为1.960~3.374,Pielou均匀度指数(Jsw)为0.448~0.681。与邻近自然保护区比较,江西北部地区岩溶地貌陆生贝类较为丰富,与其他自然保护区物种相似性较低。 相似文献
153.
通过研究深冲铀矿区γ能谱铀异常、氡浓度异常特征和激电异常特征,探索矿区范围岩体、断裂构造和蚀变带与物化探信息显示特征的关系。据此,结合矿区地质特征,总结物化探方法应用效果,矿致异常综合特征。 相似文献
154.
155.
Yardangs in terrestrial ignimbrites: Synergistic remote and field observations on Earth with applications to Mars 总被引:1,自引:0,他引:1
The conditions of formation and the form of yardangs in ignimbrites in the Central Andes of Chile, Bolivia, and Argentina may be the most convincing terrestrial analog to the processes and lithology that produce the extensive yardangs of the Medusae Fossae Formation (MFF) of Mars. Through remote and field study of yardang morphologies in the Central Andes we highlight the role that variable material properties of the host lithology plays in their final form. Here, ignimbrites typically show two main facies: an indurated and jointed facies, and a weakly to poorly indurated, ash- and pumice-rich facies. Both facies are vertically arranged in large (erupted volume >100's of km3) ignimbrites resulting in a resistant capping layer, while smaller (10's of km3) ignimbrites are made predominantly of the weakly indurated facies. The two facies have quite different mechanical properties; the indurated facies behaves as strong rock, fails by block collapse and supports steep/vertical cliffs, while the non-indurated facies is more easily eroded and forms gentle slopes and manifests as more subdued erosional forms. In response to aeolian action, the presence of an upper indurated facies results in large, elongate, high aspect ratio (1:20-1:40) megayardangs that form tall (100 m), thin ridges with steep to vertical walls. These are built on a broad apron of the weakly indurated facies with abundant fallen blocks from the upper indurated facies. These terrestrial megayardangs appear to be analogous to megayardangs with associated block fields seen on Mars. Smaller-volume, weakly indurated ignimbrites are sculpted into smaller, stubbier forms with aspect ratios of 1:5-1:10 and heights rarely exceeding 10 m. Excavation of a windward basal moat suggests an erosional progression like that seen in incipient yardangs on Mars. Excavation rates of 0.007-0.003 cm/year are calculated for the weakly indurated ignimbrites. While a persistent strong unidirectional wind is the dominant parameter controlling yardang formation and orientation, a role for flow separation and vorticity is also suggested by our observations at both yardang types. While the indurated facies is commonly pervasively jointed, jointing is of secondary importance in controlling yardang orientation. Serrated margins, a common feature on Mars, result from oblique intersections of jointing with yardang flanks or scarps of ignimbrite. The processes of yardang formation we describe from ignimbrites from the Central Andes are not necessarily specific to ignimbrites, but do connote that degree and distribution of induration is a major control in yardang formation and this has implications for the lithology of the MFF on Mars. 相似文献
156.
157.
天津市是我国水资源缺乏、人均占有淡水资源最少的城市之一,也是我国地面沉降最为严重的地区之一。地面沉降现已成为天津市的主要地质灾害,并在一定程度上制约着天津城镇的可持续发展。天津市平原区洼地众多,这些洼地大部分是天津市的湿地分布区。在洼地内建设应急地下水水源地,既可以起到为城区供水,缓解城区的地面沉降,又可以改善洼地生态环境的作用。 相似文献
158.
全域综合整治背景下的宅基地复垦项目审查是保证复垦项目合法性合规性的有效手段,针对当前宅基地复垦项目审查效率低的问题,本文提出了基于遥感影像的农村宅基地复垦项目立项真实性审查方法。首先以重庆市农村宅基地复垦项目为例,建立宅基地复垦项目立项真实性审查模型,利用改进的U-Net模型准确提取建筑物,然后与复垦红线叠加实现复垦项目真实性的智能审查。试验结果表明,该方法能够快速准确地审查复垦项目真实性,对优化土地结构、促进土地流转、实现乡村振兴具有重要意义,可为全域综合整治背景下宅基地复垦项目真实性审查提供技术参考。 相似文献
159.
160.
针对目前专门的函数信号发生器IC功能简单、精度不高、调节方式不灵活等缺点和DDS芯片外围电路设计复杂、成本较高等问题,设计研制了一种程控宽频带多波形信号发生器。该信号发生器采用单片机STC89C52控制专用函数发生器MAX038实现,通过键盘设置输出波形类型、频率、占空比和幅度等各种参数,采用闭环控制方法对输出频率自动反馈控制以提高频率精度,并由八位LED显示器实时显示状态信息。实际运行结果表明:该系统可以产生频率范围在1Hz~20MHz、幅度在2~10V(VPP)连续可调、占空比在10%~90%变化的三角波、锯齿波、方波、正弦波和PWM波,输出频率精度小于0.01%。该仪器具有电路结构简单、性能优良、成本低廉、功能多样、使用方便等优点,在生产实践和科技研究领域中具有广泛的应用前景。 相似文献