Background: Magnetic resonance image-guided radiation therapy (MR-IGRT) promises more precise and effective radiation treatments compared to conventional IGRT by using real-time on-board MR imaging. Under the influenc...Background: Magnetic resonance image-guided radiation therapy (MR-IGRT) promises more precise and effective radiation treatments compared to conventional IGRT by using real-time on-board MR imaging. Under the influence of a magnetic field, however, secondary electrons exiting a surface can be forced in a circular path and re-enter the medium, resulting in dose increase at a beam-exit surface, called the electron return effect (ERE). The purpose of the study is to compare the exit skin dose computed by Monte Carlo dose calculation with measurements using an adult anthropomorphic phantom and to measure the effect of skin dose reduction by adding 1 cm-thick bolus. Method: The plan was compared with measurements using an adult anthropomorphic phantom combined with radiochromic films and thermoluminescent dosimeters. We also measured the skin dose reduction by adding 1 cm-thick bolus on the frontal surface of the phantom. Results: We found that 1 cm-thick bolus reduced the skin dose by up to 20% both in measurements and calculations. The plan was found to overestimate the measured skin dose by about 10% and there was no significant difference in the bolus effect between the breast skin and the skin (without breast attachment) doses. Conclusion: In conclusion, we confirmed the ERE effect on the anthropomorphic phantom under the magnetic field and the exit skin dose reduction by adding a bolus. Skin dose measurements using anthropomorphic phantom may be helpful to evaluate more realistic skin dose and the bolus effect in the magnetic field.展开更多
Features and effects of returned migrant workers' entrepreneurship in Shaanxi Province are analyzed.Returned migrant workers' entrepreneurship in Shaanxi Province depends on traditional agriculture to develop ...Features and effects of returned migrant workers' entrepreneurship in Shaanxi Province are analyzed.Returned migrant workers' entrepreneurship in Shaanxi Province depends on traditional agriculture to develop the quantitative business of planting and breeding,local resources to develop the processing of building materials and agricultural products,small towns to develop service industry such as catering and tourism and the capital accumulated when working in the outside to achieve the transformation from an ordinary worker to an entrepreneur.Returned migrant workers' entrepreneurship in Shaanxi Province promotes the employment and expends ways of transferring rural labor force and increasing incomes.Advantageous recourses are attracted to the rural and underdeveloped areas,which is beneficial to narrowing the gap between the urban and rural areas.It can also promote the transformation of agricultural developmental methods and speed the pace of building modern agriculture.And a group of talents with higher qualities are provided for new rural construction through the modeling and leading role.Entrepreneurship and urbanization are combined together to advance the process of rural urbanization.展开更多
This paper considers an overall and basic definition of calendar effects,which is one of the market anomalies.As we all know,the efficient market anomalies refer to situations that are difficult to reconcile with the ...This paper considers an overall and basic definition of calendar effects,which is one of the market anomalies.As we all know,the efficient market anomalies refer to situations that are difficult to reconcile with the efficient market hypothesis.展开更多
Daily return series of Dow Jones Industrial Average Index (DJIA) and Shanghai Conposite Index are investigated using spectral analysis methods. The day of the week effect is found in the frequency domain in both ...Daily return series of Dow Jones Industrial Average Index (DJIA) and Shanghai Conposite Index are investigated using spectral analysis methods. The day of the week effect is found in the frequency domain in both stock markets. Time domain performances of the daily returns are also studied. Although both markets have a clear weekly component in the frequency domain, they show some different behaviors with respect to the day of the week effects.展开更多
Eco-compensation is an environmental economic instrument for internalization of external cost. Returning farmland to lake is one of the important parts of restoring wetland ecosystem function in the Yangtze River Vall...Eco-compensation is an environmental economic instrument for internalization of external cost. Returning farmland to lake is one of the important parts of restoring wetland ecosystem function in the Yangtze River Valley of China. Whether the project of lake recovery can be successful depends on the compensation to the farmers who have lost their original benefits and contributed to the wetland ecosystem recovery by returning farmland to lake. Aiming at the wetland recovery of the Dongting Lake, the practical implementation of pro- grams of the lake recovery and flood control in this area has been challenged by the heavy task of population resettlement, so it is an ideal area for case studies to reach the academic objectives proposed as the above. Based on field survey and experimentation, this research evaluated the benefit losses of the resettled farmers and the increased values of ecosystem service functions caused by wetland recovery, and furthermore, the value of eco-compensation for relocated farmers was calculated by considering the combination of the farmers＇ compensation appeal. The value of eco-compensation for relocated farmers in the Dongting Lake area was 6084.5 yuan per household by synthetic analysis of the effects on wetland ecosystem restoration. Moreover, this article took Dongting Lake area as a case to study and explore the basic issues of the eco-compensation by returning farmland to lake, that was who should pay, who should be paid, how much the payment was and what the payment means was, which sought the mechanisms of wetland restoration eco-compensation and prompted the people＇s enthusiasms for ecological restoration.展开更多
文摘Background: Magnetic resonance image-guided radiation therapy (MR-IGRT) promises more precise and effective radiation treatments compared to conventional IGRT by using real-time on-board MR imaging. Under the influence of a magnetic field, however, secondary electrons exiting a surface can be forced in a circular path and re-enter the medium, resulting in dose increase at a beam-exit surface, called the electron return effect (ERE). The purpose of the study is to compare the exit skin dose computed by Monte Carlo dose calculation with measurements using an adult anthropomorphic phantom and to measure the effect of skin dose reduction by adding 1 cm-thick bolus. Method: The plan was compared with measurements using an adult anthropomorphic phantom combined with radiochromic films and thermoluminescent dosimeters. We also measured the skin dose reduction by adding 1 cm-thick bolus on the frontal surface of the phantom. Results: We found that 1 cm-thick bolus reduced the skin dose by up to 20% both in measurements and calculations. The plan was found to overestimate the measured skin dose by about 10% and there was no significant difference in the bolus effect between the breast skin and the skin (without breast attachment) doses. Conclusion: In conclusion, we confirmed the ERE effect on the anthropomorphic phantom under the magnetic field and the exit skin dose reduction by adding a bolus. Skin dose measurements using anthropomorphic phantom may be helpful to evaluate more realistic skin dose and the bolus effect in the magnetic field.
基金Supported by " Studies on Problems in Migrant Workers' Entrepreneurship in Shaanxi Province" launched by Shaanxi Association of Social Sciences,Provincial Human Resources and Department of Labor and Social Secuity(2009A004)
文摘Features and effects of returned migrant workers' entrepreneurship in Shaanxi Province are analyzed.Returned migrant workers' entrepreneurship in Shaanxi Province depends on traditional agriculture to develop the quantitative business of planting and breeding,local resources to develop the processing of building materials and agricultural products,small towns to develop service industry such as catering and tourism and the capital accumulated when working in the outside to achieve the transformation from an ordinary worker to an entrepreneur.Returned migrant workers' entrepreneurship in Shaanxi Province promotes the employment and expends ways of transferring rural labor force and increasing incomes.Advantageous recourses are attracted to the rural and underdeveloped areas,which is beneficial to narrowing the gap between the urban and rural areas.It can also promote the transformation of agricultural developmental methods and speed the pace of building modern agriculture.And a group of talents with higher qualities are provided for new rural construction through the modeling and leading role.Entrepreneurship and urbanization are combined together to advance the process of rural urbanization.
文摘This paper considers an overall and basic definition of calendar effects,which is one of the market anomalies.As we all know,the efficient market anomalies refer to situations that are difficult to reconcile with the efficient market hypothesis.
文摘Daily return series of Dow Jones Industrial Average Index (DJIA) and Shanghai Conposite Index are investigated using spectral analysis methods. The day of the week effect is found in the frequency domain in both stock markets. Time domain performances of the daily returns are also studied. Although both markets have a clear weekly component in the frequency domain, they show some different behaviors with respect to the day of the week effects.
基金Social Science Foundation of Hunan Province, No.09YBA003 Science ＆ Technology Research Project of Hunan Province, No.2009JT3005+2 种基金 Knowledge Innovation Project of CAS, No.KZCX2-SW-415 Foundation of Key Laboratory for Agro-ecological Processes in Subtropical Region Wetland Project of WWF
文摘Eco-compensation is an environmental economic instrument for internalization of external cost. Returning farmland to lake is one of the important parts of restoring wetland ecosystem function in the Yangtze River Valley of China. Whether the project of lake recovery can be successful depends on the compensation to the farmers who have lost their original benefits and contributed to the wetland ecosystem recovery by returning farmland to lake. Aiming at the wetland recovery of the Dongting Lake, the practical implementation of pro- grams of the lake recovery and flood control in this area has been challenged by the heavy task of population resettlement, so it is an ideal area for case studies to reach the academic objectives proposed as the above. Based on field survey and experimentation, this research evaluated the benefit losses of the resettled farmers and the increased values of ecosystem service functions caused by wetland recovery, and furthermore, the value of eco-compensation for relocated farmers was calculated by considering the combination of the farmers＇ compensation appeal. The value of eco-compensation for relocated farmers in the Dongting Lake area was 6084.5 yuan per household by synthetic analysis of the effects on wetland ecosystem restoration. Moreover, this article took Dongting Lake area as a case to study and explore the basic issues of the eco-compensation by returning farmland to lake, that was who should pay, who should be paid, how much the payment was and what the payment means was, which sought the mechanisms of wetland restoration eco-compensation and prompted the people＇s enthusiasms for ecological restoration.
