Influential Factors in Employment Location Selection Based on “Push-Pull” Migration Theory—A Case Study in Three Gorges Reservoir Area in China

In China, farmers employed in non-farm work have become important socio-economic actors, but few studies have examined the farmers' perspective in making their work location choices. Based on "push-pull" migration theory, this paper utilizes sectional data from a 2013 survey of farmers in China's Three Gorges Reservoir area to empirically analyze the factors influencing migrant workers' choice of employment location. The results indicate that 60.46% of laborers have migrated from their home province, whereas 39.54% have remained in their home province. Focusing on personal, household, and community characteristics—in addition to the economic characteristics of the sample counties—multinomial logistic regression models reveal that farmer-laborers' employment location decisions are influenced by their personal capital endowment(age, years of education and social networks), family structure(the number of laborers, elders, children and students), home village characteristics(location, economic development level and the degree of relief of the land) and home county economic development level. Notably, male and female laborers' location decisions reveal a converging trend, and their differences are not pronounced. Per capita arable land area has little influence on location decisions, whereas the educational level of laborers has a significant impact. The results differ significantly from those found in previous studies.

Efficient Virtual Network Embedding Algorithm Based on Restrictive Selection and Optimization Theory Approach

Network virtualization(NV) is widely considered as a key component of the future network and promises to allow multiple virtual networks(VNs) with different protocols to coexist on a shared substrate network(SN). One main challenge in NV is virtual network embedding(VNE). VNE is a NPhard problem. Previous VNE algorithms in the literature are mostly heuristic, while the remaining algorithms are exact. Heuristic algorithms aim to find a feasible embedding of each VN, not optimal or sub-optimal, in polynomial time. Though presenting the optimal or sub-optimal embedding per VN, exact algorithms are too time-consuming in smallscaled networks, not to mention moderately sized networks. To make a trade-off between the heuristic and the exact, this paper presents an effective algorithm, labeled as VNE-RSOT(Restrictive Selection and Optimization Theory), to solve the VNE problem. The VNERSOT can embed virtual nodes and links per VN simultaneously. The restrictive selection contributes to selecting candidate substrate nodes and paths and largely cuts down on the number of integer variables, used in the following optimization theory approach. The VNE-RSOT fights to minimize substrate resource consumption and accommodates more VNs. To highlight the efficiency of VNERSOT, a simulation against typical and stateof-art heuristic algorithms and a pure exact algorithm is made. Numerical results reveal that virtual network request(VNR) acceptance ratio of VNE-RSOT is, at least, 10% higher than the best-behaved heuristic. Other metrics, such as the execution time, are also plotted to emphasize and highlight the efficiency of VNE-RSOT.

Impact of Labor Mobility and College Volunteers' Fixed-position Teaching Experience on Rural Households——Based on Survey Data about Teaching Sites and Volunteer Teachers

With the continuous deepening of reform and opening up,the gap between urban and rural areas continues to widen,and many farmers in rural areas have chosen to work in cities in order to get out of poverty. At the same time,in the context of the policy of precise poverty alleviation and rural rejuvenation,various helping and supporting measures for rural areas have also emerged. Supporting education in universities is one of the most important ones. With the Graduate Teaching Fellowship of Huazhong Agricultural University and the students and parents in the teaching sites as research objects,the impact of labor mobility and fixed-position supporting education in rural areas on rural families was explored in this paper using economics,sociology and other relevant theories and analytical methods. The results showed that labor mobility can promote the increase of rural household economic income. Outbound industries and regions have a major impact on the entire family development. However,the outflow of labor can also lead to various problems such as staying behind. The fixed-position supporting education in colleges and universities can,on the one hand,promote the improvement of the academic performance of the students in the teaching areas. On the other hand,it can help students develop good habits. Fixed-position supporting education of colleges and universities can be seen as a way to make up for the outflow of labor in rural areas. Combining the flow of labor force with the teaching support of colleges and universities can better promote the development of the entire family of farmers in rural areas.

Insight into selective removal of copper from high-concentration nickel solutions with XPS and DFT:New technique to prepare 5N-nickel with chelating resin

An efficient and profitable separation process was proposed to prepare 5N （the purity of the metal solution reaches 99.999%） high-purity nickel from 3N nickel-solutions using Purolite S984. The adsorption performance of this superior resin, especially its selectivity for metal ions, was explored quantitatively. The maximum adsorption capacity for copper was 2.286 mmol/g calculated by the Langmuir model, which was twice as large as that for nickel. In the binary systems, the adsorption capacity for nickel was decreased by 45%, indicating direct competition for the active sites. The infinite separation factor for copper versus nickel exceeded 300, revealing the feasibility of preparing 5N-level high-purity nickel solutions, which was further verified using the 800 BV （bed volume） effluent in the column dynamic process. According to the cost-benefit analysis, purification contributed to a profit of approximately 60,000 USD per cycle, and the investment return period was less than 1/3 years. Density functional theory analysis confirmed that four nitrogen atoms would be involved in the coordination complex and thus a structure involving two five-membered rings could be achieved. The X-ray photoelectron spectra confirmed the involvement of nitrogen atoms, implying a coordination ratio of approximately 1：1.