Regular and available supply is the prerequisite of an effective and efficient commercialization process. Using multivariate regression analysis on field data, this research appraises the production and marketing fact...Regular and available supply is the prerequisite of an effective and efficient commercialization process. Using multivariate regression analysis on field data, this research appraises the production and marketing factors that influence cassava market price. The production factors include cultivated area, planting material, yield, and farmers’ field schools;while farmers access to a paved road, having a telephone, the transportation costs of fresh roots, the level of root perishability, and the prices of rice and maize stand as marketing factors. The results show that farmers who attended farmers’ field school adopted improved planting materials, propagated them in their localities and the yields in these communities increased significantly. The farm size also has a significant influence on the availability of fresh roots. On the marketing side, transportation costs, access to a paved road, the prices of rice and maize significantly affect cassava’s market price and tighten the relationship between producers and marketers. We conclude that to increase fresh roots supply, roads leading to cultivating areas should be paved, better transportation provided, communication costs reduced, even distribution of planting materials and appropriate warehouses.展开更多
[Objective] The aim was to research influential factors of water productivity of maize in oasis in arid areas. [Method] In middle reach of Heihe River in Linze County of Zhangye City, maize, a major crop in irrigated ...[Objective] The aim was to research influential factors of water productivity of maize in oasis in arid areas. [Method] In middle reach of Heihe River in Linze County of Zhangye City, maize, a major crop in irrigated area in the oasis, was studied and nine influential factors were chosen through grey relation analysis. [Result] According to grey relation analysis, top five factors influencing water produc- tivity of maize during 1995-2009 were as follows： applied quantity of chemical fertil- izers〉labour input〉seeds〉mulch amount〉pesticide amount, which indicated that controllable factors, instead of uncontrollable ones, dominate in influence of water productivity of maize in oasis in arid areas. [Conclusion] With water resource limited, investment of controllable factors in high-efficient agricultural production should be the major strategy to improve water productivity of maize in oasis of arid areas.展开更多
This paper studies how the price movements of pork,chicken and egg respond to those of related cost factors in short terms in Chinese market.We employ a linear quantile approach not only to explore potential data hete...This paper studies how the price movements of pork,chicken and egg respond to those of related cost factors in short terms in Chinese market.We employ a linear quantile approach not only to explore potential data heteroscedasticity but also to generate confidence bands for the purpose of price stability study.We then evaluate our models by comparing the prediction intervals generated from the quantile regression models with in-sample and out-of-sample forecasts.Using monthly data from January 2000 to October 2010,we observed these findings：（i） the price changes of cost factors asymmetrically and unequally influence those of the livestock across different quantiles;（ii） the performance of our models is robust and consistent for both in-sample and out-of-sample forecasts;（iii） the confidence intervals generated from 0.05th and 0.95th quantile regression models are good methods to forecast livestock price fluctuation.展开更多
This paper analyzes Chinese enterprise industrial profit distribution and profitability rise between 1998 and 2005. Looking at it from the perspective of drivers of total growth, this paper will provide an in-depth an...This paper analyzes Chinese enterprise industrial profit distribution and profitability rise between 1998 and 2005. Looking at it from the perspective of drivers of total growth, this paper will provide an in-depth analysis of the origins and industry-level factors involved in this growth. It reaches the conclusion that structural change in profits was the main driving force for profit increases, to which heavy industry contributed greatly. Light and machine building industry profit rates improved due to increases in productivity levels, while energy and raw material industry profits increased due to increases in product prices. In addition, average wages grew slower than GDP, and wages among industries varied widely. In general however, this paper sets out to determine which enterprises gained from increases in industrial profitability, and how this gain came about.展开更多
In this paper, we consider the numerical treatment of an inverse acoustic scattering problem that involves an impenetrable obstacle embedded in a layered medium. We begin by employing a modified version of the well kn...In this paper, we consider the numerical treatment of an inverse acoustic scattering problem that involves an impenetrable obstacle embedded in a layered medium. We begin by employing a modified version of the well known <em>factorization method</em>, in which a computationally effective numerical scheme for the reconstruction of the shape of the scatterer is presented. This is possible, due to a <em>mixed reciprocity principle</em>, which renders the computation of the Green function at the background medium unnecessary. Moreover, to further refine our inversion algorithm, an efficient Tikhonov parameter choice technique, called <em>Improved Maximum Product Criterion</em> (IMPC) is exploited. Our regularization parameter is computed via a fast iterative algorithm which requires no <em>a priori</em> knowledge of the noise level in the far-field data. Finally, the effectiveness of IMPC is illustrated with various numerical examples.展开更多
文摘Regular and available supply is the prerequisite of an effective and efficient commercialization process. Using multivariate regression analysis on field data, this research appraises the production and marketing factors that influence cassava market price. The production factors include cultivated area, planting material, yield, and farmers’ field schools;while farmers access to a paved road, having a telephone, the transportation costs of fresh roots, the level of root perishability, and the prices of rice and maize stand as marketing factors. The results show that farmers who attended farmers’ field school adopted improved planting materials, propagated them in their localities and the yields in these communities increased significantly. The farm size also has a significant influence on the availability of fresh roots. On the marketing side, transportation costs, access to a paved road, the prices of rice and maize significantly affect cassava’s market price and tighten the relationship between producers and marketers. We conclude that to increase fresh roots supply, roads leading to cultivating areas should be paved, better transportation provided, communication costs reduced, even distribution of planting materials and appropriate warehouses.
基金Supported by National Natural Science Foundation of China(41161082)Gansu Natural Science Foundation(1107RJZA167)~~
文摘[Objective] The aim was to research influential factors of water productivity of maize in oasis in arid areas. [Method] In middle reach of Heihe River in Linze County of Zhangye City, maize, a major crop in irrigated area in the oasis, was studied and nine influential factors were chosen through grey relation analysis. [Result] According to grey relation analysis, top five factors influencing water produc- tivity of maize during 1995-2009 were as follows： applied quantity of chemical fertil- izers〉labour input〉seeds〉mulch amount〉pesticide amount, which indicated that controllable factors, instead of uncontrollable ones, dominate in influence of water productivity of maize in oasis in arid areas. [Conclusion] With water resource limited, investment of controllable factors in high-efficient agricultural production should be the major strategy to improve water productivity of maize in oasis of arid areas.
基金supported by the Key Project of National Key Technology R&D Program of China(2009BADA9B01)
文摘This paper studies how the price movements of pork,chicken and egg respond to those of related cost factors in short terms in Chinese market.We employ a linear quantile approach not only to explore potential data heteroscedasticity but also to generate confidence bands for the purpose of price stability study.We then evaluate our models by comparing the prediction intervals generated from the quantile regression models with in-sample and out-of-sample forecasts.Using monthly data from January 2000 to October 2010,we observed these findings：（i） the price changes of cost factors asymmetrically and unequally influence those of the livestock across different quantiles;（ii） the performance of our models is robust and consistent for both in-sample and out-of-sample forecasts;（iii） the confidence intervals generated from 0.05th and 0.95th quantile regression models are good methods to forecast livestock price fluctuation.
文摘This paper analyzes Chinese enterprise industrial profit distribution and profitability rise between 1998 and 2005. Looking at it from the perspective of drivers of total growth, this paper will provide an in-depth analysis of the origins and industry-level factors involved in this growth. It reaches the conclusion that structural change in profits was the main driving force for profit increases, to which heavy industry contributed greatly. Light and machine building industry profit rates improved due to increases in productivity levels, while energy and raw material industry profits increased due to increases in product prices. In addition, average wages grew slower than GDP, and wages among industries varied widely. In general however, this paper sets out to determine which enterprises gained from increases in industrial profitability, and how this gain came about.
文摘In this paper, we consider the numerical treatment of an inverse acoustic scattering problem that involves an impenetrable obstacle embedded in a layered medium. We begin by employing a modified version of the well known <em>factorization method</em>, in which a computationally effective numerical scheme for the reconstruction of the shape of the scatterer is presented. This is possible, due to a <em>mixed reciprocity principle</em>, which renders the computation of the Green function at the background medium unnecessary. Moreover, to further refine our inversion algorithm, an efficient Tikhonov parameter choice technique, called <em>Improved Maximum Product Criterion</em> (IMPC) is exploited. Our regularization parameter is computed via a fast iterative algorithm which requires no <em>a priori</em> knowledge of the noise level in the far-field data. Finally, the effectiveness of IMPC is illustrated with various numerical examples.
