Multipurpose agroforestry as a climate change resiliency option for farmers: an example of local adaptation in Vietnam

Increasing frequency, intensity and duration of severe weather events are posing major challenges to global food security and livelihoods of rural people. Agriculture has evolved through adaptation to local circumstances for thousands of years. Local experience in responding to severe weather conditions, accumulated over generations and centuries, is valuable for developing adaptation options to current climate change. This study aimed to: (i) identify tree species that reduce vulnerability of cropping systems under climate variability; and (ii) develop a method for rapidly assessing vulnerability and exploring strategies of smallholder farmers in rural areas exposed to climate variability. Participatory Rural Appraisal methods in combination with Geographical Information Systems tools and statistical analysis of meteorological data were used to evaluate local vulnerability to climate change and to investigate local adaptation measures in two selected villages in Vietnam, one of the countries most vulnerable to climate change. The low predictability of severe weather events makes food crops, especially grain production, insecure. This study shows that while rice and rain-fed crops suffered over 40 % yield losses in years of extreme drought or flood, tree-based systems and cattle were less affected. 13 tree species performed well under the harsh local climate conditions in home and forest gardens to provide income, food, feed and other environmental benefits. Thus, this research suggests that maintenance and enhancement of locally evolved agroforestry systems, with high resilience and multiple benefits, can contribute to climate change adaptation.     

Identification of anthropogenic radionuclides in the Song Hong (Red) and Song Da (Black) river basins of Vietnam

The concentration and distribution of U were measured in zircon samples separated from the streambed sediments collected at different sites along the rivers of northern Vietnam using semiconductor alpha spectrometry and alpha- and fission-track autoradiography. Based on the absolute U content and distribution, we distinguished two groups of zircon grains of different origin. Group 1 zircons have relatively low and uniform U contents ranging from 280 to 440 μg/g. Group 2 zircons are characterized by heterogeneous U distribution and U contents ranging from 490 to 2040μg/g. The determination of absolute alpha activity values and alpha spectrometric characteristics for a number of group 2 zircon grains indicated the presence of relatively short-lived alpha-emitters. These radionuclides are probably ²¹⁰Po, ²³²U, ²³⁶Pu, ²⁴¹Am, and ²⁴³Am, and all of them can originate exclusively from anthropogenic sources. A comparison of the observed alpha activity values for group 2 zircons with those of group 1 zircons and zircons separated from the suspended colloids in river water samples provided conclusive evidence for traces of anthropogenic radioactive contamination in the Lao Cai, Yen Bai, Tuyen Quang, Thac Ba, Viet Tri, and Hanoi streams flowing in the Song Hong (Red) and Song Da (Black) river basins of northern Vietnam and sourced in the southern regions of the neighboring state.     

Microbiota of Salt Lakes as Food for the Brine Shrimp Artemia

正The brine shrimp Artemia is often abundantly found in hypersaline environments.The larvae(‘nauplii’)hatching from its dormant embryos(‘cysts’)are a crucial live food item for the larval stages of fish and shrimp in aquaculture     

A new SPH-based approach to simulation of granular flows using viscous damping and stress regularisation

The smoothed particle hydrodynamics (SPH) method was recently extended to simulate granular materials by the authors and demonstrated to be a powerful continuum numerical method to deal with the post-flow behaviour of granular materials. However, most existing SPH simulations of granular flows suffer from significant stress oscillation during the post-failure process, despite the use of an artificial viscosity to damp out stress fluctuation. In this paper, a new SPH approach combining viscous damping with stress/strain regularisation is proposed for simulations of granular flows. It is shown that the proposed SPH algorithm can improve the overall accuracy of the SPH performance by accurately predicting the smooth stress distribution during the post-failure process. It can also effectively remove the stress oscillation issue in the standard SPH model without having to use the standard SPH artificial viscosity that requires unphysical parameters. The predictions by the proposed SPH approach show very good agreement with experimental and numerical results reported in the literature. This suggests that the proposed method could be considered as a promising continuum alternative for simulations of granular flows.     

Modelling the Mont Terri HE-D experiment for the Thermal–Hydraulic–Mechanical response of a bedded argillaceous formation to heating

Coupled thermal–hydrological–mechanical (THM) processes in the near field of deep geological repositories can influence several safety features of the engineered and geological barriers. Among those features are: the possibility of damage in the host rock, the time for re-saturation of the bentonite, and the perturbations in the hydraulic regime in both the rock and engineered seals. Within the international cooperative code-validation project DECOVALEX-2015, eight research teams developed models to simulate an in situ heater experiment, called HE-D, in Opalinus Clay at the Mont Terri Underground Research Laboratory in Switzerland. The models were developed from the theory of poroelasticity in order to simulate the coupled THM processes that prevailed during the experiment and thereby to characterize the in situ THM properties of Opalinus Clay. The modelling results for the evolution of temperature, pore water pressure, and deformation at different points are consistent among the research teams and compare favourably with the experimental data in terms of trends and absolute values. The models were able to reproduce the main physical processes of the experiment. In particular, most teams simulated temperature and thermally induced pore water pressure well, including spatial variations caused by inherent anisotropy due to bedding.     

Climate change and groundwater resources in Mekong Delta,Vietnam

Groundwater resources have considerable influences on the human population and socioeconomic development of Vietnam and the Mekong River Delta (MRD). This paper presents an overview of the relationship between climate change and groundwater in the MRD, including the challenges, strategies and technical measures. Our results showed that groundwater levels are related to other climate and hydrological variables (i.e., rainfall, river levels, etc.); therefore, the impacts of climate change on the groundwater resources of the Mekong delta are significant, especially on groundwater recharge. Based on the results of this study, it is recommended that groundwater development in the future should focus on reducing groundwater harvesting, enhancing groundwater quantity by establishing artificial works and exploiting surface water. This study suggests that the Artificial Neural Network (ANN) model is an effective tool for forecasting groundwater levels in periods of 1 month and 3 months for aquifers in the natural and tidal regime areas of the delta.     

基于WebGIS的旅游景区空间智能评价系统研究

针对现有信息系统在空间智能评价方面的薄弱之处,运用WebGIS空间智能集成方法探讨旅游景区空间智能评价系统的设计和实现,从三方面提高了旅游景区评价系统的智能化层次:通过集成旅游景区网上调查问卷系统,提高了数据收集提取的智能化层次;通过集成旅游景区模糊综合评价模型、客流结构评价模型及旅游专家知识系统,增强了评价系统的半结构化智能推理功能;采用B/S C/S系统构架,并利用Web技术提高了人机交互界面的智能化。周庄景区案例评价结果显示,该系统原型的运行效果良好且智能化层次较高。     

河北平原地下水开发中的问题及可持续利用

河北平原是我国严重缺水地区，但在地下水开发过程中，引起了多种环境问题，如地下水位持续下降；地下水位降落漏斗不断扩大，地下含水层疏干；地面发生沉降及出现地裂缝；海、咸水入侵等等。作者从水资源、环境和社会经济的特点出发，提出实现水资源和社会经济可持续发展的对策：全面实施节水战略，努力实现工业、农业、居民生活、生态环境的高效用水，逐步建立起节水型社会；提高城市污水资源化利用率；利用海水、咸水、减少淡水用量；实施跨流域调水；保护水资源和改善水环境是缓解河北平原缺水和环境问题的重要措施。