Managing Water Supply Operations in the Caribbean

This paper describes the characteristics and problems of water resources and water supply systems in the United States Virgin Islands and indicates the ways in which those are shared by other small islands of the Caribbean and West Atlantic. The history of development of the water supply, including groundwater, desalination and barging, is described as well as supply and demand factors and management of the system. Institutional issues are discussed and the applicability of Virgin Island experience to other islands is analyzed. Cet article décrit les caractéristiques et les problèmes des ressources aquifères et des réseaux de distribution d'eau dans les Iles Vierges américaines. II montre la façon dont les autres petites Iles des Caraibes et de l'Atlantique occidental partagent ces ressources et réseaux de distribution. L'article fait l'historique de l'approvisionnement en eau, y compris les eaux souterraines et décrit la dessalinisation et le transport par barges. II étudie également l'offre et la demande et les problèmes de gestion. II examine les questions institutionnelles et analyse la manière dont l'expérience des Iles Vierges peut ětre appliquée aux autres ǐles. Este artículo describe las características y los problemas del suministro y recursos de agua en las Islas Virgenes (USA) e indica como los mismos problemas se encuentran en otras pequenas islas del Caribe y el Atlántico Oriental. El articulo cubre el desarrollo histórico del suminstro de agua, incluyendo agua subterranea, desalinización y transporte marítimo de agua, y analiza los aspectos de la oferta y la demanda de agua y la administración de los sistemas de suministro. Se discute también los aspectos institucionales y la posible aplicación de la experiencia ganada en otras áreas geográficas.     

泥石流暴发的应力自组织临界特性

泥石流是一种严重的自然灾害。从广延能量耗散的角度看，泥石流暴发的应力演化过程是一种自组织临界过程。斜坡松散碎屑土触变液化系统在暴雨激发下，内部不同因子间的相互非线性作用，导致斜坡碎屑土自然地朝临界极限应力状态发展，最终暴发泥石流。本文以应力的自组织观点，分析了泥石流暴发的特性。蒋家沟泥石流的资料显示，泥石流规模与频率间存在着幂律关系，这说明泥石流活动具有自组织临界的特性。     

粘性泥石流体阵性流形成机理研究

通过粘性泥石流体阵性流的野外观测 ,和应用最新研制的大型平板旋转式泥石流流变仪测定粘性泥石流体的应力应变特性 ,发现含有砾石的粘性泥石流体启动时具有明显的应力过冲特征。这种应力过冲特征 ,与由粘性介质阻力形变初期的剪切稀化和高浓度粗细颗粒相互挤压的内摩擦力共同组成的泥石流体的应力滞后特性 (抗剪强度 )有关。根据所测定的粘性泥石流体的准静摩擦角、正压力和动摩擦系数 ,通过剪切面上流动坡度的推导与泥石流体启动高度的演算 ,并与粘性泥石流体阵性流观测资料进行对比 ,初步揭示了粘性泥石流体阵性流的形成机理。     

Detecting Rare Species with Random or Subjective Sampling: a Case Study of Red-Listed Saproxylic Beetles in Boreal Sweden

Abstract:  Efficient sampling design in field studies is important for economical and statistical reasons. We compared two ways to distribute sampling effort over an area, either randomly or subjectively. We searched for red-listed saproxylic (wood-living) beetles in 30 spruce stands in boreal Sweden by sifting wood from dead trees. We randomly selected positions within each stand with a geographic positioning system and sampled the nearest dead tree (random sample). In the same stand we also sampled dead trees that, based on literature, were likely to host such species (subjective sampling). The subjective sampling (two to five samples per stand, depending on stand size) was compared with the higher, random sampling effort (fixed level of 12 samples/stand). Subjective sampling was significantly more efficient. Red-listed species were found in 36% of the subjective samples and in 16% of the random samples. Nevertheless, the larger random effort resulted in a comparable number of red-listed species per stand and in 13 detected species in total (vs. 12 species with subjective sampling). Random sampling was less efficient, but provided an unbiased alternative more suitable for statistical purposes, as needed in, for example, monitoring programs. Moreover, new species-specific knowledge can be gained through random searches.     

Golf Course Development in a Major Tourist Destination: Implications for Planning and Management

The planning and design of golf course developments is influenced by many factors. This paper focuses on the environmental ramifications of insufficient or lack of compliance with standard environmental and economic planning practices. Specifically, it looks at a tourist destination location that was under the influence of extensive land development and investment speculation. The Gold Coast in Australia was the focal point for large overseas investment due to changes in government legislation regarding foreign investment. Due to the economic climate in the second half of the 1980s many golf course resort developments were built, approved, or planned. Many of these circumvented normal business and environment planning processes. The result has been a dangerous concentration of golf facilities in environmentally sensitive areas and an oversupply of golf facilities. Both of these matters are discussed in terms of the general planning process and the potential economic and environmental impacts to the Gold Coast and similar destinations in other parts of the world.