Dry/wet climate zoning and delimitation of arid areas of Northwest China based on a data-driven fashion

The division of arid areas is important in water and land resources management, planning and for a long-term agricultural, economic and social planning. Northwest China （NW） dominates the main arid areas in China. There is thus a need to adopt adequate concepts relative to the scope of arid areas of NW China and identify its climate types and characteristics. In this study, we analyzed climatic data over the last 30 years （1981-2010） from 191 stations in three provinces and three autonomous regions of NW China. The factor-cluster analysis technique （FC）, an objective and automated method was employed to classify the dry/wet climate zones. The traditional methods with predefined thresholds were adopted for providing a comparison with FC. The results showed that the wet/dry climate zones by FC were mainly distributed along mountains, rivers and desert borders. Climate-division boundaries relied heavily on the major terrain features surrounding the grouped stations. It also showed that the climate was dry in the plain sandy areas but relatively wet in the high mountain areas. FC method can reflect the climate characteristics more fully in NW China with varied and complicated topography, and outperform the tradi- tional climate classifications. Arid areas of NW China were defined as four climate types, including five resultant classes in FC classifications. The Qinling and Da Hinggan Mountains were two important boundaries, besides main administrative boundaries. The results also indicated that there are some differences between two traditional clas- sifications. The precipitation moved and fluctuated to an extent, which confirmed that climate change played an important role in the dry/wet climate zoning, and the boundaries of dry/wet climate zones might change and migrate with time. This paper is expected to provide a more in-depth understanding on the climate characteristics in arid areas of NW China, and then contribute to formulate reasonable water and land management planning and agri- cultural production programs.

Enhanced soft magnetic properties of iron powders through coating MnZn ferrite by one-step sol–gel synthesis

The MnZn ferrite coating formed on the surface of iron-based soft magnetic powders via facile and modified sol–gel process has been fabricated to obtain better magnetic performance due to its higher permeability compared with traditional nonmagnetic insulation coatings. The influence of the MnZn ferrite contents on the magnetic performance of the soft magnetic composites(SMCs) has been studied. As the MnZn insulation content increases, the core loss first experiences a decreasing trend that is followed by progressive increase, while the permeability follows an increasing trend and subsequently degrades. The optimized magnetic performance is achieved with 2.0 wt% MnZn ferrite, which results from the decrement of inter-particle eddy current losses based on loss separation. A uniform and compact coating layer composed of MnZn ferrite and oxides with an average thickness of 0.38 ± 0.08 μm is obtained by utilizing ion beam technology, and the interface between the powders and the coating shows satisfied adhesiveness compared with the sample directly prepared by mechanical mixing. The evolution of the coating layers during the calcination process has been presented based on careful analysis of the composition and microstructure.

Changes in the Brain’s Intrinsic Organization in the Resting State with Real-Time fMRI Neurofeedback Training of Posterior Cingulate Cortex Activity

Real-time functional magnetic resonance imaging (rtfMRI) technology has been widely used to train subjects to actively regulate the activity of specific brain regions. Although many previous studies have demonstrated that neurofeedback training alters the functional connectivity between brain regions in the task state and resting state, it is unclear how the regulation of the key hub of the default mode network (DMN) affects the topological properties of the resting-state brain network. The current study aimed to investigate what topological changes would occur in the large-scale intrinsic organization of the resting state after the real-time down-regulation of the posterior cingulate cortex (PCC). The results indicated that the down-regulation of the PCC in the DMN reduced the functional connectivity of the PCC with the nodes outside of the DMN and reduced functional connectivity between the superior medial frontal gyrus (SFGmed) and parahippocampal gyrus (PHG) in the experimental group. Moreover, the nodal graph properties of the SFGmed were reduced, while that of the PHG showed the opposite alteration after the down-regulation of the PCC. These findings possibly suggest that the regulation of the key hub of the DMN, the PCC, mainly changed the information transfer of the SFGmed and PHG.

区域主要作物生产实体水-虚拟水耦合流动过程解析与评价

水安全是粮食安全的刚性基础.在农业生产过程中(产前、产中、产后)自然-经济-社会(三元)因素驱动下,其水资源消耗形成实体水-虚拟水(二维)嵌入转化、互为反馈、相互影响的耦合流动过程.本文基于实体水-虚拟水"二维三元"耦合流动理论,集成构建了以水量为参数的区域作物生产广义实体水-虚拟水耦合流动过程量化方法,并应用于我国"丝绸之路经济带"沿线西部六省,对其1985~2013年主要作物实体水-虚拟水耦合流动过程进行解析与评价.揭示了区域作物生产实体水-虚拟水耦合流动现象,发现六省间水资源消耗与流动存在资源与经济效益的此消彼长现象.表明以农田尺度实体节水为目标的资源单视角传统农业水资源管理理念,已不足以实现多空间尺度水资源的资源-经济同步高效利用的管理目标,而具有资源-经济-社会三重意义的区域农业全产业链实体水-虚拟水统筹管理应为有效解决思路.基于此,初步提出三点思考:(1)现代农业节水应实体水-虚拟水统筹考虑;(2)需加快突破农业生产实体水-虚拟水耦合流动量化、评价方法与调控关键技术;(3)建议基于农业全产业链视角,建立基于实体水-虚拟水二维度理论的农业水资源管理体系,确保实现各阶段水资源管理"三条红线".

A data envelopment analysis of agricultural technical efficiency of Northwest Arid Areas in China

Severe resource shortage and waste of resource in agricultural production make it necessary to assess efficiency to increase productivity with high efficiency and ensure sustainable agricultural development. This paper adopted an input-oriented data envelopment analysis(DEA) method with the assumption of variable returns to scale to evaluate agricultural production efficiency of 100 major irrigation districts in Northwest China in 2010.Major findings of this paper were as follows: firstly, the average value of total technical efficiency, pure technical efficiency and scale efficiency of those irrigation districts in Northwest China were 0.770, 0.825 and 0.931,respectively; secondly, 30% of irrigation districts were technically efficient, while 42% and 32% of them showed pure technical and scale efficiency respectively. Among inefficient decision-making units, total technical efficiency score varied from 0.313 to 0.966, showing significant geographical differences, but geographical differences of pure technical efficiency was more consistent with that of total technical efficiency; thirdly, input redundancy was evident. Inputs of agricultural population, irrigation area,green water, blue water, consumption of fertilizer and agricultural machinery could be reduced by 34.88%,40.19%, 43.85%, 47.10%, 41.53% and 42.21% respectively without reducing agricultural outputs. Furthermore,irrigation area, green water and blue water had relatively high slack movement though Northwest China which is short of water resources. Based on these results, this paper drew the following conclusions: First, there is huge potential for Northwest China to improve its agricultural production efficiency, and agro-technology not input scale had greater influence on improvement. Second, farmers needed proper guidance in order to reduce agricultural inputs and it is time to centralize agricultural management for overall agricultural inputs regulation and control.

Spatiotemporal variation in water footprint of grain production in China

Water shortage has become a significant constraint to grain production in China.A more holistic approach is needed to understand the links between grain production and water consumption.Water footprint provides a framework to assess water utilization in agriculture production.This paper analyzes the spatiotemporal variation in water footprint of grain production(WFGP)in China from 1951 to 2010.The results show that,jointly motivated by the improvement of agricultural production and water use efficiency,WFGP in all areas showed a decreasing trend.National average WFGP has decreased from 3.38 to 1.31 m^(3)·kg^(–1).Due to regional differences in agricultural production and water use efficiency,spatial distribution of WFGP varies significantly and its pattern has changed through time.Moreover,WFGP may show significant differences within areas of similar climatic conditions and agricultural practices,indicating that there is a strong need to improve the management of water use technology.Statistical analysis revealed that regional differences in grain yield are the main cause for variations in spatiotemporal WFGP.However,the scope for further increases in grain yield is limited,and thus,the future goal of reducing WFGP is to decrease the water use per unit area.

Nutritional value of detoxified Jatropha curcas seed cake protein isolates using rats as an animal model

A bioassay study was conducted to investigate the effects of substituting casein with graded levels of detoxified Jatropha curcas seed cake protein isolates(JPI) as a protein source on the growth performance,feed efficiency ratio(FER) and its protein values using rats as an animal model. Thirty 21-day-old male Spraguee Dawley weaned rats were randomly divided into 5 groups, each group with 6 replications(n = 1). Each group consumed one of the following diets: protein-free, casein(CAS) and JPI diets(JPI20,JPI40 and JPI60; different levels of JPI to replace the casein at concentrations of 20%, 40% and 60% on crude protein basis). Feed intake and protein intake showed no difference among the rats fed JPI20, JPI40 and CAS diets(P > 0.05). However, these parameters were lower in the rats fed JPI60 than in rats fed CAS(P < 0.05). The rats fed diets containing JPI had lower body weight gain, protein efficiency ratio and net protein retention than those fed CAS diet(P < 0.05). When the level of JPI used to replace the casein was lower than 40%, protein efficiency ratio(PER) was close to or higher than 2.0, which suggests that JPI could be viewed as a high-quality protein. Inclusion of JPI in the diet decreased alkaline phosphatase activity. The values were significantly lower in rats fed JPI20 and JPI40than in rats fed CAS(P < 0.05). No histopathological changes were observed in livers and kidneys in the rats fed JPI diets. The results demonstrate that JPI could be used as an efficient protein source at a level of no more than 40% of dietary protein source.