On Disturbances Introduced by Impulse Source into Stratified Two-Component Media

The paper considers the problem concerning the response of a stably stratified two-component medium (salt water, moist air) in the presence of a stationary source of vertical impulse. For a homogeneous vertical distribution of the impulse source (i.e., the applied vertical force), due to the symmetry of the problem, one succeeded in finding the explicit analytical solution of the stationary problem for arbitrary source amplitude. The solution is expressed through Kelvin’s cylindrical functions and represents the stationary vertical jet. The two-component character of the medium can influence substantially the quality of the properties of the solution. In particular, the jet parameters are not defined uniquely by the buoyancy frequency (density stratification). In the solution, the stratifications of the two hydrodynamic components have the distinctive influences that are defined by values of corresponding exchange coefficients. For example, in salt water the solution dependence on salinity stratification may be much more than on temperature stratification.     

长沙市旅游开发生态适宜性评价

在借鉴已有评价方法的基础上,从宏观的角度,以长沙市为例,选取了区域生态环境、旅游资源价值、社会经济因子3个方面的评价因子,建立起旅游生态适宜性评价因子体系。采用模糊层次分析法确定评价因子权重,并在G IS技术的支持下,从空间上对其旅游开发的生态适宜性进行了综合评价。研究结果表明,长沙市旅游用地可以划分为最适宜用地、适宜用地、基本适宜用地、不适宜用地、不可用地,适合于进行旅游开发的区域较大,最适宜用地、适宜用地、基本适宜用地达到7 549.66 km2,占63.74%。     

环境水体中三氟乙酸的存在现状及分析方法的研究

三氟乙酸是一种氟里昂替代品的大气降解产物 ,雨水会将其从空气中去除转移到水体中。三氟乙酸化学性质稳定 ,在自然环境中三氟乙酸易于积累在水体中 ,环境地表水中三氟乙酸浓度可达到 1 0～ 4 0 90 0 ng/L,雨水中 30～ 2 80 ng/L。目前 ,环境水体中关于三氟乙酸的分析方法有 :气相色谱法 ,离子色谱法 ,气相色谱质谱联用。根据各种灵敏度的要求 ,再结合各种不同的前处理方法 ,可对环境水体中三氟乙酸进行分析     

Emergency drills for agricultural drought response: a case study in Guatemala

Drills are an important element of disaster management, helping to increase preparedness and reduce the risk of real‐time failure. Yet, they are not applied systematically to slow‐onset disasters such as a drought, which causes damage that is not instantly apparent and thus does not solicit immediate action. This case study evaluates how drills inform institutional responses to slow‐onset disasters. It spotlights Guatemala, a country where drought has severe impacts on livelihoods and the food security of small farmers. By implementing part of the Ministry of Agriculture, Livestock and Food's institutional response plan for drought, it explores how drills can help to detect issues in emergency response and to foster an institutional focus on improvements in preparedness. The results reveal that drills alone do not trigger institutional improvements if unsupported by a wider strategy that seeks to enhance capacities and protocols. These findings are valuable, however, in making problems transparent and in creating the space for discussion.     

Five challenges to reconcile agricultural land use and forest ecosystem services in Southeast Asia

Southeast Asia possesses the highest rates of tropical deforestation globally and exceptional levels of species richness and endemism. Many countries in the region are also recognized for their food insecurity and poverty, making the reconciliation of agricultural production and forest conservation a particular priority. This reconciliation requires recognition of the trade‐offs between competing land‐use values and the subsequent incorporation of this information into policy making. To date, such reconciliation has been relatively unsuccessful across much of Southeast Asia. We propose an ecosystem services (ES) value‐internalization framework that identifies the key challenges to such reconciliation. These challenges include lack of accessible ES valuation techniques; limited knowledge of the links between forests, food security, and human well‐being; weak demand and political will for the integration of ES in economic activities and environmental regulation; a disconnect between decision makers and ES valuation; and lack of transparent discussion platforms where stakeholders can work toward consensus on negotiated land‐use management decisions. Key research priorities to overcome these challenges are developing easy‐to‐use ES valuation techniques; quantifying links between forests and well‐being that go beyond economic values; understanding factors that prevent the incorporation of ES into markets, regulations, and environmental certification schemes; understanding how to integrate ES valuation into policy making processes, and determining how to reduce corruption and power plays in land‐use planning processes.     

Trade‐offs and efficiencies in optimal budget‐constrained multispecies corridor networks

Conservation biologists recognize that a system of isolated protected areas will be necessary but insufficient to meet biodiversity objectives. Current approaches to connecting core conservation areas through corridors consider optimal corridor placement based on a single optimization goal: commonly, maximizing the movement for a target species across a network of protected areas. We show that designing corridors for single species based on purely ecological criteria leads to extremely expensive linkages that are suboptimal for multispecies connectivity objectives. Similarly, acquiring the least‐expensive linkages leads to ecologically poor solutions. We developed algorithms for optimizing corridors for multispecies use given a specific budget. We applied our approach in western Montana to demonstrate how the solutions may be used to evaluate trade‐offs in connectivity for 2 species with different habitat requirements, different core areas, and different conservation values under different budgets. We evaluated corridors that were optimal for each species individually and for both species jointly. Incorporating a budget constraint and jointly optimizing for both species resulted in corridors that were close to the individual species movement‐potential optima but with substantial cost savings. Our approach produced corridors that were within 14% and 11% of the best possible corridor connectivity for grizzly bears (Ursus arctos) and wolverines (Gulo gulo), respectively, and saved 75% of the cost. Similarly, joint optimization under a combined budget resulted in improved connectivity for both species relative to splitting the budget in 2 to optimize for each species individually. Our results demonstrate economies of scale and complementarities conservation planners can achieve by optimizing corridor designs for financial costs and for multiple species connectivity jointly. We believe that our approach will facilitate corridor conservation by reducing acquisition costs and by allowing derived corridors to more closely reflect conservation priorities.     

How economics can further the success of ecological restoration

Restoration scientists and practitioners have recently begun to include economic and social aspects in the design and investment decisions for restoration projects. With few exceptions, ecological restoration studies that include economics focus solely on evaluating costs of restoration projects. However, economic principles, tools, and instruments can be applied to a range of other factors that affect project success. We considered the relevance of applying economics to address 4 key challenges of ecological restoration: assessing social and economic benefits, estimating overall costs, project prioritization and selection, and long‐term financing of restoration programs. We found it is uncommon to consider all types of benefits (such as nonmarket values) and costs (such as transaction costs) in restoration programs. Total benefit of a restoration project can be estimated using market prices and various nonmarket valuation techniques. Total cost of a project can be estimated using methods based on property or land‐sale prices, such as hedonic pricing method and organizational surveys. Securing continuous (or long‐term) funding is also vital to accomplishing restoration goals and can be achieved by establishing synergy with existing programs, public–private partnerships, and financing through taxation.     

北京能源消费排放CO2增量的影响因素分析——基于三层嵌套式的I-O SDA技术

通过构建一个扩展的竞争型经济-能源-碳排放投入产出表,运用三层嵌套结构式I-O SDA 技术,从整体情况、分产业、工业分行业3 个层面,对1997—2007 年北京的碳排放增量进行了分解。结果表明:消费、投资、调出和出口等经济规模增长要素,以272.46%的贡献率成为增排的主要因素,而能源消费强度变动效应,则以-237.13%的贡献率成为减排的决定性因素;在规模扩张各效应中,调出和消费超过投资和出口达8 403.38×10⁴ t,是增排的主要贡献者;2002—2007 年间以“高碳”为特征的新一轮工业化,使该期增排占到1997—2007年总增量的86.41%;服务业的贡献率是75.93%,为增排的第一大部门,但2002—2007 年工业超出服务业1 036.40×10⁴ t;重制造业的贡献率是1 030.76%,为增排的重点行业,而能源工业则以-992.81%的贡献率,成为减排的重点行业;各时段各效应在不同产业、工业不同行业发挥的作用大小不同且不够稳定。     

基于外部效应分析机井密度对地下水位的影响

农用机井的迅猛发展使地下水灌溉在我国的粮食生产中发挥了重要作用,但同时也使地下水面临超采严重和水位下降的严峻形势。为了可持续地利用地下水资源,政府需采取必要措施。鉴于地下水使用中存在的外部效应,合理控制机井密度可能是值得政府考虑的重要举措之一。然而,现有文献对机井密度与地下水位之间的关系仍缺乏实证分析。本研究以兰考县为案例研究区,结合有关部门的机井普查数据和研究小组搜集的农户调研数据,利用空间分析和计量模型分析,发现机井密度与地下水位之间具有显著的关系。具体而言,当某一机井100 m半径范围内的机井数目每增加一眼,该机井的水位显著下降约15 cm;机井密度对水位的边际影响随半径范围的扩大而下降。研究建议：政府在今后应采取有关措施控制机井密度,加强地下水取水许可证制度建设等配套措施。     

Potential economic impact of introduction and spread of the red imported fire ant, Solenopsis invicta, in Hawaii

Globally, many invasive alien species have caused extensive ecological and economic damage from either accidental or intentional introduction. The red imported fire ant, Solenopsis invicta, has created billions of dollars in costs annually, spreading as an invasive species across the southern United States. In 1998, the red imported fire ant spread into California creating a highly probable future introduction via shipped products to Hawaii. This paper presents the estimation of potential economic impacts of the red imported fire ant (RIFA) to the state of Hawaii. Evaluation of impacts focuses on the economic sectors of (1) households, (2) agriculture (cattle and crop production), (3) infrastructure (cemeteries, churches, cities, electrical, telephone, and cable services, highways, hospitals and schools), (4) recreation, tourism and business (hotels/resort areas, golf courses, commercial businesses and tourists), and (5) government expenditures (with minimal intervention). The full annual economic costs of the red imported fire ant to Hawaii are estimated (in US$ 2006) to be $211 million/year, comprised of $77 million in damages and expenditures and $134 million in foregone outdoor opportunities to households and tourists. The present value of the projected costs of RIFA over a 20-year period after introduction total $2.5 billion. RIFA invasions across the globe indicate that economic cost-effective action in Hawaii entails implementation of prevention, early detection and rapid response treatment programs for RIFA.