The role of economics in integrated river basin management

River basin managementEconomic aspectsWater allocation

Metabolomics in Early Alzheimer's Disease: Identification of Altered Plasma Sphingolipidome Using Shotgun Lipidomics

The development of plasma biomarkers could facilitate early detection, risk assessment and therapeutic monitoring in Alzheimer's disease (AD). Alterations in ceramides and sphingomyelins have been postulated to play a role in amyloidogensis and inflammatory stress related neuronal apoptosis; however few studies have conducted a comprehensive analysis of the sphingolipidome in AD plasma using analytical platforms with accuracy, sensitivity and reproducibility.We prospectively analyzed plasma from 26 AD patients (mean MMSE 21) and 26 cognitively normal controls in a non-targeted approach using multi-dimensional mass spectrometry-based shotgun lipidomics to determine the levels of over 800 molecular species of lipids. These data were then correlated with diagnosis, apolipoprotein E4 genotype and cognitive performance. Plasma levels of species of sphingolipids were significantly altered in AD. Of the 33 sphingomyelin species tested, 8 molecular species, particularly those containing long aliphatic chains such as 22 and 24 carbon atoms, were significantly lower (p<0.05) in AD compared to controls. Levels of 2 ceramide species (N16:0 and N21:0) were significantly higher in AD (p<0.05) with a similar, but weaker, trend for 5 other species. Ratios of ceramide to sphingomyelin species containing identical fatty acyl chains differed significantly between AD patients and controls. MMSE scores were correlated with altered mass levels of both N20:2 SM and OH-N25:0 ceramides (p<0.004) though lipid abnormalities were observed in mild and moderate AD. Within AD subjects, there were also genotype specific differences.In this prospective study, we used a sensitive multimodality platform to identify and characterize an essentially uniform but opposite pattern of disruption in sphingomyelin and ceramide mass levels in AD plasma. Given the role of brain sphingolipids in neuronal function, our findings provide new insights into the AD sphingolipidome and the potential use of metabolomic signatures as peripheral biomarkers

An Economic Analysis of Shallow Groundwater Management for Nature Conservation and Agricultural Production

Lowering of shallow groundwater levels in agricultural areas with ecological value leads to desiccation of ecosystems. The aim of this paper is to develop a model to study the trade-offs between the agricultural production value and the monetary value of the ecological benefits of agricultural nature management as a result of changes in shallow groundwater levels. It shows that socially optimal groundwater levels depend on: (1) the agricultural production value; (2) the monetary value of nature; (3) the soil type and vegetation; and (4) the relative share of agricultural area with ecological value in total agricultural area.

Assessing impacts of dike construction on the flood dynamics of the Mekong Delta

Recent flood dynamics of the Mekong Delta have raised concerns about an increased flood risk downstream in the Vietnamese Mekong Delta. Accelerated high dike building on the floodplains of the upper delta to allow triple cropping of rice has been linked to higher river water levels in the downstream city of Can Tho. This paper assesses the hydraulic impacts of upstream dike construction on the flood hazard downstream in the Vietnamese Mekong Delta. We combined the existing one-dimensional (1-D) Mekong Delta hydrodynamic model with a quasi-two-dimensional (2-D) approach. First we calibrated and validated the model using flood data from 2011 and 2013. We then applied the model to explore the downstream water dynamics under various scenarios of high dike construction in An Giang Province and the Long Xuyen Quadrangle. Calculations of water balances allowed us to trace the propagation and distribution of flood volumes over the delta under the different scenarios. Model results indicate that extensive construction of high dikes on the upstream floodplains has had limited effect on peak river water levels downstream in Can Tho. Instead, the model shows that the impacts of dike construction, in terms of peak river water levels, are concentrated and amplified in the upstream reaches of the delta. According to our water balance analysis, river water levels in Can Tho have remained relatively stable, as greater volumes of floodwater have been diverted away from the Long Xuyen Quadrangle than the retention volume lost due to dike construction. Our findings expand on previous work on the impacts of water control infrastructure on flood risk and floodwater regimes across the delta

Remote Sensing and Economic Indicators for Supporting Water Resources Management Decisions

This paper demonstrates that combining spatial land surface data with socio-economic analysis provides a number of indicators to strengthen decision making in integrated water and environmental management. It provides a basis to: track current water consumption in the Inkomati Basin in South-Africa; adjust irrigation water management; select crop types; facilitate planning; estimate crop yields before harvesting, and consequently to forecast market price development. Remote sensing data and economic analysis can also be used to study the spatial distribution of water consumption as an indicator of equity in access to water resources. It even enables identification of farms that consume more irrigation water than formally allocated. Finally, it provides a basis to assess the cost-effectiveness of various ways to reduce agricultural water consumption. So, this approach is potentially useful for determining water consumption, refining water allocation policies, and determining the potential for water transfers through mechanisms such as water trading.Water ManagementCivil Engineering and Geoscience