ADO.NET在农业信息网上的应用研究

介绍了ASP.NET适合开发农业信息网站的优势。以SQL SERVER为例,介绍了利用ASP.NET开发技术和ADO.NET数据库操作技术,实现对农业数据库的基本操作,并且给出了相应的代码。利用该技术能够有效缓解当前访问数据库所存在的困难。     

The determination of ecological status in shallow lakes — a tested system (ECOFRAME) for implementation of the European Water Framework Directive

• 1. The European Water Framework Directive requires the determination of ecological status in European fresh and saline waters. This is to be through the establishment of a typology of surface water bodies, the determination of reference (high status) conditions in each element (ecotype) of the typology and of lower grades of status (good, moderate, poor and bad) for each ecotype. It then requires classification of the status of the water bodies and their restoration to at least ‘good status’ in a specified period.
• 2. Though there are many methods for assessing water quality, none has the scope of that defined in the Directive. The provisions of the Directive require a wide range of variables to be measured and give only general guidance as to how systems of classification should be established. This raises issues of comparability across States and of the costs of making the determinations.
• 3. Using expert workshops and subsequent field testing, a practicable pan‐European typology and classification system has been developed for shallow lakes, which can easily be extended to all lakes. It is parsimonious in its choice of determinands, but based on current limnological understanding and therefore as cost‐effective as possible.
• 4. A core typology is described, which can be expanded easily in particular States to meet local conditions. The core includes 48 ecotypes across the entire European climate gradient and incorporates climate, lake area, geology of the catchment and conductivity.
• 5. The classification system is founded on a liberal interpretation of Annexes in the Directive and uses variables that are inexpensive to measure and ecologically relevant. The need for taxonomic expertise is minimized.
• 6. The scheme has been through eight iterations, two of which were tested in the field on tranches of 66 lakes. The final version, Version 8, is offered for operational testing and further refinement by statutory authorities.

Copyright © 2003 John Wiley & Sons, Ltd.     

Harmonising sediment criteria of North sea and Rhine river Basin

As a result of convenants between the Port of Rotterdam and the German Chemical Industry, the emissions in the Rhine between Basle (Switzerland) and the Dutch boarder have fallen by more than half in the past fifteen years. Recent studies have concluded that people are nowadays polluting the Rhine more than industry. This places Rotterdam’s involvement with the quality of water and the sediment of the Rhine, port and North Sea in a different perspective. As a medium-sized European municipality, Rotterdam doesn’t want to take on too much, certainly not when cross-border issues such as the quality of the North Sea and the Rhine water are concerned. Rotterdam is now trying to get other organisations to co-operate in solving this problem. A cleaner Rhine, after the success on point sources, can be achieved primarily by reducing the contamination from diffuse sources, over which the port itself has absolutely no control. Rotterdam is the homeport of Mrs. Els Kuijper. She gave a keynote lecture during the SedNet Inaugural Conference, April 22–23, 2002, which forms the basis of this article. Mrs. Kuijper is the vice-mayor and environmental alderman of Rotterdam.     

Ontogenetic and spatial variations in brown trout habitat selection

Ayllón D, Almodóvar A, Nicola GG, Elvira B. Ontogenetic and spatial variations in brown trout habitat selection.
Ecology of Freshwater Fish 2010: 19: 420–432. © 2010 John Wiley & Sons A/S Abstract – Habitat quality and quantity determine many biological processes and traits that directly affect the population dynamics of stream fishes. Understanding how habitat selection is adjusted to different ecological conditions is essential to improve predictive modelling of population dynamics. We describe brown trout Salmo trutta summer habitat selection patterns through univariate and multivariate habitat selection functions across defined river reach typologies. We sampled 44 sites and performed a principal component analysis that defined eight reach types differing in both local site and catchment‐scale physical features. We observed ontogenetic changes in habitat selection, as trout preferred deeper and slower flowing water as they increased in size. Likewise, selectivity for different types of structural habitat elements changed through ontogeny. Both patterns were consistent across reach types. Moreover, we detected spatial variations in habitat selection patterns within age‐classes among different reach types. Our results indicate that brown trout is a habitat generalist and suggest that spatial variations in habitat selection patterns are driven by physical and environmental factors operating at multiple spatial scales.     

Road to shared prosperity: The elaboration and influence of a transboundary policy narrative for regional economic integration

In the Mekong Region, the Asian Development Bank and partners have promoted economic corridors as a way to achieve regional economic integration and growth. This study evaluates how a transboundary policy narrative of shared prosperity around the East–West Economic Corridor programme emerged, and then how it was elaborated and used, taking a set of border policies of the government of Thailand as cases. For two decades the shared prosperity narrative has been used by a coalition of elite actors to support a programme of investments in road infrastructure, as well as to push for agreements on trade, border logistics, investment and tourism. The shared prosperity narrative has helped maintain support for the programme despite its failures to meet projections and expectations. Although criticised by civil society and experts from time to time, no coherent shared counter‐narrative emerged. Policy elites in Thailand have used the transboundary narrative to justify investments in special economic zones, and transport infrastructure near the border and inside neighbouring countries. Thailand has also reproduced the narrative in support of efforts to bolster tourism cooperation, and negotiate cross‐border trade and logistics agreements. Roads and bridges have been built, underlining how discursive practices have material consequences and reinforce the narrative.     

Using Large Wood to Restore Streams in Central Europe: Potential use and Likely Effects

The potentials for the use of large wood (LW) in stream restoration projects were quantified for streams in Central Europe (total stream length assessed 44,880 km). Two different restoration methods were investigated: recruitment (passively allowing natural LW input) and placement (active introduction of large wood pieces into streams). The feasibility and potential effects of each method were studied for three different scenarios, according to the land-uses to be permitted on the floodplain: (a) only natural-non woody vegetation, forest, and fallow land occur on the floodplain, (b) including pasture and meadow, (c) including pasture, meadow, and cropland. Hydromorphological data were used to identify stream sections where LW recruitment or placement are feasible, and the likely effects of both restoration methods on channel hydromorphology were predicted. Passive recruitment is feasible for only a small percentage of the total channel length in the study area (~1% for all three scenarios). Active placement of LW can be used in much higher extent: 6.5% if only natural non-woody vegetation, forest, and fallow land can occur on the floodplain, 20.2% if stream segments bordered by pasture and meadow are included, and 32% if cropland is included in addition. There are differences between (1) the lower-mountainous area, where a large number of channel segments can be restored yielding an improvement from a moderate/good to a good/excellent morphological status and (2) the lowlands, where only a small number of channel segments can be restored yielding an improvement from a bad to a moderate morphological state. The latter upgrading might be sufficient to reach a ‘good ecological status’ as defined by the EU Water Framework Directive. The results of this study show the suitability of large wood recruitment and placement as appropriate methods to markedly improve the hydromorphological state of a large proportion of the streams in the study area.     

欧盟海洋综合战略框架指令及其对中国海洋生态文明建设的借鉴

欧盟海洋综合战略框架指令采用基于生态系统管理方法,以实现其海洋环境良好状况,对我国海洋生态文明红线制度的建设具有借鉴作用。文章分析了该指令的构成及其实施指标等,比较其与我国海洋生态红线制度的异同点。最后,文章认为欧盟指令的协调机制值得借鉴,把海洋生态文明建设相关管理制度整合起来,形成综合有机的框架体系;完善公众参与制度对于落实海洋生态文明建设也是至关重要的。     

Aspects of phosphorus transfer from soils in Europe

Imbalanced nutrient management has caused soil phosphorus (P) to become an environmental rather an agronomic problem in more economically developed countries. This subject has been the topic of numerous journal special issues, conferences, and reviews but we consider yet another review of this subject is necessary with the main target of providing a point of view on nonpoint transfer from soils and control strategies for an improved environmental management of P. This review considers the causes of the excessive P transfer from soil to surface water in Europe and the scientific knowledge necessary to develop control strategies.