“反其率术”校注

就尚存争议的《九章算术》中“反其率术”进行研究 ,结合刘徽、李淳风的九章注 ,分析“经率术”、“其率术”、“反其率术”的内在联系和变化 ,以算理分析和实际验证的方法考察“反其率术”,从而获得对“反其率术”术文校正和算法的阐释。

Measurement of Technical, AIIocative and Economic Efficiency of Tomato Farms in Northern Pakistan

The study measures productive efficiency of tomato growers in village Akbarpura of Disctrict Nowshera in Khyber Pakhtunkhwa （KPK） province of Northern Pakistan. The study uses household level data collected in summer 2010 from sample farmers selected by multi-staged sampling. The study uses a theoretical framework to measure productive efficiency and estimates the Cobb-Douglas frontier production and cost models. The study found that technical efficiency indices varied significantly, with technical efficiency index averaging at 65%. The indices of allocative efficiency also varied widely, with an average of 56%. There was a wide gap between the highest and lowest economic efficiency indices, with a mean economic efficiency of 35%. The study concluded that farmer education, extension visits, age and access to credit contributed significantly and positively to productive efficiencies. A policy implication of this study is that there is enough potential for farmers to increase tomato production and net profits. The study recommends that the government should further invest in public education and strengthen extension services farmer education and because extension visits constituted important determinants of productive efficiencies.

Urban Water Resource Utilization Efficiency in China

The efficient use of water resources directly affects environmental, social, and economic development; therefore, it has a significant impact on urban populations. A slacks-based measure for data envelopment analysis （SBM-DEA） has been widely used in energy efficiency and environmental efficiency analyses in recent years. Based on this model, data from 316 cities were examined and a category method was employed involving three different sorting techniques to empirically evaluate the efficiency of urban water re- source utilization in China between 2000 and 2012. The overall efficiency （OE） of urban water resource utilization in China was initially low, but has improved over the past decade. The scale efficiency （SE） was higher than the pure technological efficiency （PTE）; PTE is a major determining factor of OE, and has had an increasingly significant effect. The efficiency of water resource utilization varied ac- cording to the region, urban scale, and economic function. The OE score for the eastern China was higher than for the rest of the region, and the OE score for the western China was higher than for the central China. The OE score for urban water resource utilization has improved with urban expansion, except in the case of small cities. The SE showed an inverted U-shaped＇ trend with increasing urban expansion. The OE of urban water utilization in comprehensive functional cities was greater than in economic specialization cities, and was greater in heavy industry specialization cities than in other specialization cities. This study contributes to the field of urban water resource management by examining variations in efficiency with urban ~ezle

How to choose the most appropriate technique for the single-stage treatment of cholecysto-choledocolithiasis?

Background:We utilized transcystic clearance and intra-operative papillotomy through a rendezvous technique for the treatment of cholecysto-choledocolithiasis.The goal of this study was to evaluate the reliability of pre-operative parameters to address the most suitable surgical procedure.Methods:A total of 180 patients affected by calculi of the gallbladder and bile duct underwent the single-stage treatment.According to several pre-operative parameters,141 patients had to supposedly undergo transcystic clearance of the bile duct,while 39 patients had to be treated with the rendezvous technique.All patients were treated with the sequential procedure:first,we tried the transcystic procedure and,if there was a failure,we used a rendezvous technique.We prospectively analysed each group based on a series of variables such as sex,age,operative time,success rate of proposed treatment,conversion rate,post-operative complications and hospital stay.Results:Transcystic clearance was successful in 134 out of 141 patients(95.0%),while 2 patients needed to undergo a laparo-endoscopy procedure(failure).Thirty-five out of 39 patients(89.7%)obtained common bile-duct(CBD)clearance through the rendezvous technique,while 1 patient obtained clean-up through the simple transcystic procedure(failure).Five out of 141 patients with transcystic clearance and 3 out of 39 patients with the rendezvous technique underwent laparotomy CBD clearance with conversion rates of 3.5%and 7.7%,respectively.Post-operative complications showed similar percentages for both procedures.However,the surgical time turned out to be longer for the rendezvous technique.Conclusions:The one-stage procedure for the treatment of cholecysto-choledocolithiasis was possible in 94%of the cases utilizing a surgical technique selected according to the patient’s case history.The pre-operative parameters,such as jaundice,CBD diameters and stone diameters,have certified their reliability as good predictors of the most suitable procedure to follow.