The bivalve Lembulus bicuspidatus may enhance denitrification in shelf sediment at the Angola–Benguela Frontal Zone     

A Neumann  A Flohr 《African Journal of Marine Science》2018,40(1):91-96

We collected living individuals of the bivalve Lembulus bicuspidatus, which shows an unusual preference for the oxygen-deficient habitat found at the Angola–Benguela Frontal Zone of the southeastern Atlantic. With a series of incubation experiments with ¹⁵N-labelled nitrate as a tracer in combination with membrane-inlet mass spectrometry, we studied the potential contribution of L. bicuspidatus to nitrate reduction in the upper sediment layer. Our preliminary results suggest that L. bicuspidatus enhances nitrate reduction if the oxygen concentration is sufficiently low. The Lembulus-mediated nitrate reduction rate is then similar to the rate of microbial nitrate reduction in the surrounding sediment.  相似文献   

基于高斯两步移动搜寻法的村镇避难场所可达性研究     

但文羽  肖映辉  胡周灵  詹庆明 《地球信息科学学报》2018,20(10):1412-1421

避难场所可达性是指避难场所与受灾居民之间的通达性,即灾害发生时,避难人员通过避难疏散通道到达避难场所的难易程度,是评价避难场所布局合理性的重要指标。本研究结合高斯两步移动搜寻法和网络分析法,从供需双向出发对村镇地区避难场所进行可达性分析。2种方法的结合,既充分考虑了需求点与设施点的相互作用,又充分考虑了设施点的吸引力随距离的衰减关系,并基于实际道路,以步行疏散时间作为搜索半径,降低了传统研究中因忽略供需间相互作用及实际距离而引起的可达性结果的误差。最后,以神农架松柏镇区为例,验证该方法的实际应用价值。结果表明,该方法能够有效测定村镇地区避难场所的空间可达性,同时,基于GIS软件可以直观地揭示研究区域内避难场所可达性空间分布差异。该方法可为制定科学的村镇防灾减灾规划提供方法支持。  相似文献   

乡村空间重构的理论研究进展与理论框架构建     

金利霞  文志敏  范建红  杜志威 《热带地理》2020,40(5):765-774

在新时代城乡融合发展、乡村地域人地关系日益复杂的背景下，乡村空间重构成为乡村地理学研究的重要课题。西方“后生产主义”语境下，乡村空间研究开始出现消费转向、社会-文化转向和后现代转向，多功能、全球化乡村转型与空间重构研究成为西方乡村空间研究的热点；国内研究主要基于乡村地理学人地关系地域系统理论展开乡村空间重构过程—机理—调控研究以及微观视角下农户经济空间行为研究；当前，中国乡村空间重构呈现自上而下的政治经济学转型特征，具有中国特色的农村集体组织与政府、企业、个人等其他主体之间的空间-权力关系成为乡村空间重构的重要视角。政治经济地理学及“社会-空间”二元辩证法为乡村空间重构研究提供了很好的研究范式与研究方法，乡村空间重构研究应系统整合空间生产、主体能动性、土地资本化、社会关系网络、人地关系地域系统和农户地理等政治经济学、地理学理论，强化自然、经济、社会和文化等多要素相互作用及其空间响应机制研究，重点开展多要素多维度的乡村空间格局形成及演变规律研究、乡村社会空间再生产研究、能动性视角下乡村劳动力空间生产研究、政府政策制度与城乡空间治理体系创新研究。  相似文献   

农村信用社产权制度创新研究     

李权昆 《广东海洋大学学报》2002,22(5):35-38

现行农村信用社存在的出资人所有权虚置、收益权削弱、法人财产权丧失等产权制度缺陷 ,严重阻碍着它的进一步发展。形成这些缺陷的主要原因在于农村信用社产权改革的方向不明和对产权范畴的片面理解 ,因此 ,农村信用社产权制度创新应在清晰界定产权的基础上、向股份制、股份合作制、合作制等多种产权形式的方向发展。  相似文献   

A STUDY ON LAND SYSTEM INNOVATIONS IN THE CONSTRUCTION OF SMALL TOWNS IN CHINA     

LIANGLin－ke  CHANGJiang 《中国地理科学(英文版)》2002,12(1):80-85

The economic development in China and the rising of the living standard need to speed up the urbanisa-tion.The development of small towns is an important way to Chinese urbanization.Land use plays a very important role in the development of small towns.However there are many problems in the development of small towns,esp.in land use.The paper first discusses the land problems in the development of small towns.Such as much cultivated land lies idle,under-utilization and waste of land,increasing illegal use of land,unstable contractural relationship for land use.The relationship between the development of small towns and land use is also studied.Then the guidelines for the land system innovations of small towns are put forward.Namely the sustainability of social and economic development,the bal-ance between land reservation and land utilization,the provision of service to village ,agriculture and farmer,the manage-ment of land resource and land assets,the parsimonious andlegal use of land.The basic framework of land system innova-tions of small towns is put forward finally.It include the land replacement policy for small towns and the permanent tenan-cy of farmland,the overall plan for land uses and other plans in harmony,the establishment of a flexible system of land supplies,using land with payments ,the transfer of agricultural land and refining the land law related to the construction of small towns.  相似文献   

FEASIBLE STUDY ON THE INTEGRATION SYSTEM FOR THE SPACE MONITORING OF MAJOR EARTHQUAKES AND VOLCANOES IN TERRESTRIAL LAND   总被引：1，自引：1，他引：0  

BOLi-qun 《中国地理科学(英文版)》2002,12(4):350-353

With the rapid development of space technology, earth observation technology and sky observatory technolo-gy, they have played a more and more important part in monitoring and predicting of earthquakes and volcanoes in the terres-trial land. In recent years, the related agencies have done the experiments and researches on monitoring and predicting ofearthquakes and volcanoes in the forewarning period by means of many approaches, such as satellite thermal infrared re-mote sensing (TIRS), Global Positioning System (GPS), differential interferometric synthesis aperture radar (D-INSAR),astronomical time-latitude residual anomaly, and Geographic Information Systems (GIS), etc. A quite large number of re-search foundation has been built in the fundamental theories and application methods. The experiments and researcheshave shown that these technology is efficient methods for high frequency crust movement. If the existed separate scientificforces and results are possibly assembled together to form a more complete integration monitoring system with the combina-tion of space, sky observation, ground, deep geology and macro anomaly, it will come into a new stage of monitoring andpredicting of earthquakes and volcanic eruptions.  相似文献   

GDJ人卫目视观测数据采集和处理系统的研制     

何妙婵 《天文研究与技术》1996,(1)

本文介绍了ＧＤＪ跟踪打印经纬仪在人造卫星的观测中如何应用计算机对多圈卫星的目视观测资料进行实时采集、处理等工作过程的原理和方法。  相似文献   

流星暴的航天定义     

马月华  徐品新  李广宇  包纲 《天文学报》2005,46(2):158-164

定义ZHR^*以每小时穿过1000平方公里天顶截面的，能在铝质表面打出直径不小于1厘米的弹坑的流星体数，作为流星群对航天安全威胁强度的定量标志，给出了从ZHR到ZHR^*的换算公式．用ZHR^*取代ZHR来评价20世纪90年代以来的一些强流星雨，发现1998年的贾可比尼(天龙座)流星雨对航天安全来说，是比公认的1999、2001、2002年3次狮子座流星暴强数倍的更强流星暴．  相似文献   

中国1∶100万景观生态制图设计   总被引：5，自引：0，他引：5  

程维明  柴慧霞龙恩  刘海江张旸 《地球信息科学学报》2004,6(4):19-24

中国1∶100万景观生态图系借鉴国内外传统景观制图方法和制图规范,在遥感、地理信息系统先进技术的支持下,设计研制其制图方法、制图内容、样图和技术流程,同时提出初步的景观分类系统,为今后编制中国1∶100万景观生态图奠定基础。  相似文献   

ENVIRONMENTAL SUSTAINABILITY AND SCENARIOS OF URBANIZATION IN ARID AREA——A Case Study in Wuwei City of Gansu Province   总被引：1，自引：0，他引：1  

YOUFei LIYu DONGSuo-cheng 《中国地理科学(英文版)》2005,15(2):120-130

1IN T R O D U C T IO N The western China isfacinggrowing problems of eco- logicaland economic development. The disparitiebse- tween the socio-economy of the western and eastern China were enlarging, and the major ecologicalprob- lems stilelvolve as past(H…  相似文献