Over the last 30 years,China’s small commodity market has been a big driving force for economic growth,and the city of Yiwu is the largest small commodity market in China.Its stong vitality today gives us a picture i...Over the last 30 years,China’s small commodity market has been a big driving force for economic growth,and the city of Yiwu is the largest small commodity market in China.Its stong vitality today gives us a picture into how China’s economy remains so strong.展开更多
With the gradual recovery of the global economy,China's rare earth import and export trade has resumed growth.In 2023,China's total import and export of various rare earths and rare earth magnetic materials re...With the gradual recovery of the global economy,China's rare earth import and export trade has resumed growth.In 2023,China's total import and export of various rare earths and rare earth magnetic materials reached 290,000 tons,a year-on-year increase of 24%.However,due to the decline in rare earth commodity prices.展开更多
Rubber producers,consumers,traders,and those who are involved in the rubber industry face major risks of rubber price fluctuations.As a result,decision-makers are required to make an accurate estimation of the price o...Rubber producers,consumers,traders,and those who are involved in the rubber industry face major risks of rubber price fluctuations.As a result,decision-makers are required to make an accurate estimation of the price of rubber.This paper aims to propose hybrid intelligent models,which can be utilized to forecast the price of rubber in Malaysia by employing monthly Malaysia’s rubber pricing data,spanning from January 2016 to March 2021.The projected hybrid model consists of different algorithms with the symbolic Radial Basis Functions Neural Network k-Satisfiability Logic Mining(RBFNN-kSAT).These algorithms,including Grey Wolf Optimization Algorithm,Artificial Bee Colony Algorithm,and Particle Swarm Optimization Algorithm were utilized in the forecasting data analysis.Several factors,which affect the monthly price of rubber,such as rubber production,total exports of rubber,total imports of rubber,stocks of rubber,currency exchange rate,and crude oil prices were also considered in the analysis.To evaluate the results of the introduced model,a comparison has been conducted for each model to identify the most optimum model for forecasting the price of rubber.The findings showed that GWO with RBFNN-kSAT represents the most accurate and efficient model compared with ABC with RBFNNkSAT and PSO with RBFNN-kSAT in forecasting the price of rubber.The GWO with RBFNN-kSAT obtained the greatest average accuracy(92%),with a better correlation coefficient R=0.983871 than ABC with RBFNN-kSAT and PSO with RBFNN-kSAT.Furthermore,the empirical results of this study provided several directions for policymakers to make the right decision in terms of devising proper measures in the industry to address frequent price changes so that the Malaysian rubber industry maintains dominance in the international markets.展开更多
Health Products and Technologies (HPTs) are pivotal for an efficient health system. Availability and accessibility to affordable health products are critical indicators towards achieving universal health coverage. Rou...Health Products and Technologies (HPTs) are pivotal for an efficient health system. Availability and accessibility to affordable health products are critical indicators towards achieving universal health coverage. Routine supportive supervision, performance monitoring, recognition of efforts and client feedback are vital activities toward health supply chain system strengthening. This is a descriptive paper that describes a model of integrated commodity supportive supervision, and mentorship and its impact on various outcomes of health commodity management. Data were abstracted from the standardized scored checklists used during integrated commodity supportive supervision and supply chain audit in public health facilities in Vihiga County. Scores for the period 2020 to 2022 were analyzed on the eight key areas of interest. The analysis was done using Statistical Package for Social Sciences (SPSS version 26). Results are interpreted at 95% Confidence interval. This paper also shares findings from both quantitative and qualitative data from client exit and facility managers’ interviews. Six complete rounds of supervisions, three clients and service providers’ interviews, and three annual award events have been conducted. We observed trends across six data collections points and compared the results at first point or baseline (January-June 2020) to the results at the last point or end line (April-June 2022). Findings show significant improvements on the eight parameters in terms of mean scores as follows: resolution of issues from previous visits by 35.06% (46.75% - 81.81%);storage of HPTs by 17.41% (68.72% - 86.13%);inventory management by 28.16% (42.67% - 70.83%);availability and use of commodity data management information systems (MIS) tools by 22.39% (74.40% - 96.79%);verification of commodity data by 25.61% (65.56% - 91.17%);availability of guidelines and job aids for commodity management by 46.28% (36.65% - 82.93%). There was an improvement on the mean score on accountability by 20.22% (58.58% - 83.51%). The composite (final) score improved by 28.33% (56.19% - 84.52%). There was progressive narrowing of the standard deviations on all the indicators across the study period. This demonstrates that there is standardization of practices and positive competition among all the public health facilities. There were significant improvements on all the eight indicators. Routine integrated commodity supportive supervision has proven to be an effective high impact intervention in improving management of health products and technologies in Vihiga County, Kenya.展开更多
According to OECD standards(United Nations,2008),“productivity is commonly defined as a ratio of a volume measure of output to a volume measure of input use”.This ratio indicates how efficiently production inputs,su...According to OECD standards(United Nations,2008),“productivity is commonly defined as a ratio of a volume measure of output to a volume measure of input use”.This ratio indicates how efficiently production inputs,such as labour and capital,are being used in an economy to produce a given level of outputs.Productivity stays aside the main aggregates of national accounts,as the national income(a proxy of GDP),the total output and the circulating capital.Assume the existence of a Leontief-type national Input-Output Table with the vector of total output and the vector of intermediate inputs,situated on its right and lower border.In this paper a measure of capital productivity is proposed.It is called the productiveness,and results from the solution of a boundary value problem,elaborated for Input-Output Tables,involving the vector of total output and the vector of intermediate inputs.展开更多
Nowadays,the carbon markets in the world have increasingly matured and carbon trading have flourished in China.In the framework of carbon trading,the carbon emission right has become a tradable special commodity,and i...Nowadays,the carbon markets in the world have increasingly matured and carbon trading have flourished in China.In the framework of carbon trading,the carbon emission right has become a tradable special commodity,and it has financial feature and asset feature.Relying on the business entities,carbon assets management joins up the virtual carbon emission right,financial capital and real economy,restructures existing carbon resources of enterprises and impacts the current international economic pattern.At present,however,the carbon assets management systems and market rules of our country remains to be perfect.How to increase the efficiency of carbon asset management,how to further improve the carbon management,how to further improve the carbon asset management method and mechanism have become the common issue of China’s academia and practice.展开更多
The present study aims to analyze the growing Sino-Brazilian trade relationship and how China has contributed to the commodity price boom in the recent period.Throughout the article,it was possible to identify that th...The present study aims to analyze the growing Sino-Brazilian trade relationship and how China has contributed to the commodity price boom in the recent period.Throughout the article,it was possible to identify that the export and import agenda between countries differs in terms of number of products and technological intensity,so that imported products are capital intensive,while exported products are predominantly commodities.The text is divided into two main sections,firstly addressing the literature review on the commodities boom and highlighting the“China effect”.The second section analyzes trade between the countries,so that the trade relationship has followed an increasing trajectory since 2003.As of 2009,China has become Brazil’s main trading partner,surpassing historical partners such as the United States and Argentina.展开更多
Nini Dog of Huaiyang County,one of the provincial-level intangible cultural heritage of Henan,has high artistic,cultural and archaeological value.It is proposed that protection and inheritance of national cultures,as ...Nini Dog of Huaiyang County,one of the provincial-level intangible cultural heritage of Henan,has high artistic,cultural and archaeological value.It is proposed that protection and inheritance of national cultures,as well as innovation based on the inheritance are of great significance to improve the marketing and economic efficiency of these cultures.On this basis,the necessity of further development of Nini Dog commodities is analyzed,which is the need of both tourism development and its own development.This study through full investigation gives the orientation of Nini Dog commodities,potential consumers are classified into 3 groups:people interested in traditional cultures,tourists and children;consumer psychology is analyzed and then design orientation of Nini Dog is proposed,it is stressed that identity design should be enhanced to establish brands,creative commodity design promoted to explore new development thoughts,and composite design encouraged to expand the market.By doing this,the study aims at providing design and development guidance for the future development of Nini Dog commodities.展开更多
Objective:To report demographic and injury characteristics of tendo-Achilles(TA)injury,and determine its association with the use of Indian style commode seat(ISCS),the clinical and functional outcomes.Methods:This ob...Objective:To report demographic and injury characteristics of tendo-Achilles(TA)injury,and determine its association with the use of Indian style commode seat(ISCS),the clinical and functional outcomes.Methods:This observational study was conducted between 1 January 2016 and 31 December 2019,and a total of 44 patients with TA injury were included in the study.Their demographic profile,etiology,operative details,and functional outcomes were studied.All patients underwent primary repair followed by standard postoperative management and follow-up for 6 months.Results:Out of 44 patients,7(15.9%)sustained closed injuries while 37(84.1%)sustained open injuries.In open injury cases,30(81%)patients suffered an injury due to slipping in ISCS,4(11%)from road traffic accidents,and 3(8%)due to falling of a heavy object.Besides,20.45%of cases of ISCS injury had associated neurovascular injury.Twenty(45%)patients took more than 90 days to start independent ambulation.At 6 months follow-up,no one could reach pre-injury fitness status.Conclusions:Open TA injury by ISCS is an important,under-reported,and preventable cause of loss of physically active manpower in institutional setups.展开更多
Of all the existing materials, plastics are no doubt among the most versatile ones. However, the extreme increases in plastic production as well as the difficulty of the material for degradation have led to a huge num...Of all the existing materials, plastics are no doubt among the most versatile ones. However, the extreme increases in plastic production as well as the difficulty of the material for degradation have led to a huge number of plastic wastes. Their recycling rate after disposal is less than 10%, resulting in a series of serious environmental and ecological problems as well as a significant waste of resources. Current recycling methods generally suffer from large energy consumption, the low utilization rate of recycled products with low added value, and produce other waste during the process. Here, we summarized recentlydeveloped chemical recycling ways on commodity plastics, especially new catalytic paths in production of fuels, high-valued chemicals and advanced materials from a single virgin or a mixture of plastic waste,which have emerged as promising ways to valorize waste plastics more economically and environmentally friendly. The new catalyst design criteria as well as innovative catalytic paths and technologies for plastic upcycling are highlighted. Beyond energy recovery by incineration, these approaches demonstrate how waste plastics can be a viable feedstock for energy use with the generation of clean H_(2), high-quality liquid fuels and materials for energy storage, and help inspiring more catalytic process on plastic upcycling to overcome the economical hurdle and building a circular plastic economy.展开更多
Fluctuations in commodity prices should influence mining operations to continually update and adjust their mine plans in order to capture additional value under new market conditions. One of the adjustments is the cha...Fluctuations in commodity prices should influence mining operations to continually update and adjust their mine plans in order to capture additional value under new market conditions. One of the adjustments is the change in production sequencing. This paper seeks to present a method for quantifying the net present value(NPV) that may be directly attributed to the change in commodity prices. The evaluation is conducted across ten copper price scenarios. Discrete event simulation combined with mixed integer programming was used to attain a viable production strategy and to generate optimal mine plans. The analysis indicates that an increase in prices results in an increased in the NPV from$96.57M to $755.65M. In an environment where mining operations must be striving to gain as much value as possible from the rights to exploit a finite resource, it is not appropriate to keep operating under the same mine plan if commodity prices alter during the course of operations.展开更多
[ Objective] The paper was to screen out ideal biological pesticides, in order to provide guidance for pollution-free control against Pieris rapae Linne. [Method] Taking Chinese cabbage variety Taiyuan Erqing as the t...[ Objective] The paper was to screen out ideal biological pesticides, in order to provide guidance for pollution-free control against Pieris rapae Linne. [Method] Taking Chinese cabbage variety Taiyuan Erqing as the test material, the field control efficiencies of four pesticides including PrGV · Bt WP 1 000 times dilution, NPV · Bt SC 750 times dilution, 0.5% azadirachtin EC 750 times dilution, and 0.3% matrine AS 500 times dilution against P. rapae were studied, and their impacts on yield and planting benefits of Chinese cabbage were also determined. Using foliar spray method, the pesticides were sprayed for the first time when the second or third instar larvae of P. rapae first occurred in fields, and sprayed for the second time with the interval of 15 d. The fields sprayed with beta-cypermethrin EC (organic chemical pesticide) and water were set as control. [ Result] NPV · Bt SC 750 times dilution had the best effect after spraying for two times: the control efficiency against P. rapae at 15 d after spraying was 90.11% ; the damage rate of Chinese cabbage was only 0.21%, while the commodity rate reached 100% ; compared with chemical pesticide spraying, the commodity yield (177 262.5 kg/hm2 ) and the income after deducting spraying cost (48 858.5 yuan/hm2 ) were increased by 14.7% and 13.75%, respectively. [ Conclusion] Although biological pesticides are more expensive, they have long persistence and good control effect, resulting in green and safe Chinese cabbage with high commodity rate and yield, and higher eventual economic benefit after deducting spraying cost.展开更多
Forecasting mineral commodity(MC) prices has been an important and difficult task traditionally addressed by econometric, stochastic-Gaussian and time series techniques. None of these techniques has proved suitable to...Forecasting mineral commodity(MC) prices has been an important and difficult task traditionally addressed by econometric, stochastic-Gaussian and time series techniques. None of these techniques has proved suitable to represent the dynamic behavior and time related nature of MC markets. Chaos theory(CT) and machine learning(ML) techniques are able to represent the temporal relationships of variables and their evolution has been used separately to better understand and represent MC markets. CT can determine a system's dynamics in the form of time delay and embedding dimension. However, this information has often been solely used to describe the system's behavior and not for forecasting.Compared to traditional techniques, ML has better performance for forecasting MC prices, due to its capacity for finding patterns governing the system's dynamics. However, the rational nature of economic problems increases concerns regarding the use of hidden patterns for forecasting. Therefore, it is uncertain if variables selected and hidden patterns found by ML can represent the economic rationality.Despite their refined features for representing system dynamics, the separate use of either CT or ML does not provide the expected realistic accuracy. By itself, neither CT nor ML are able to identify the main variables affecting systems, recognize the relation and influence of variables though time, and discover hidden patterns governing systems evolution simultaneously. This paper discusses the necessity to adapt and combine CT and ML to obtain a more realistic representation of MC market behavior to forecast long-term price trends.展开更多
This work aimed to develop a healthier meat product, by improving nutritional properties related to lipid profile, using a Maillard reaction product (MRP) obtained from recycling blood from local slaughterhouses as an...This work aimed to develop a healthier meat product, by improving nutritional properties related to lipid profile, using a Maillard reaction product (MRP) obtained from recycling blood from local slaughterhouses as antioxidant. Soybean oil was used as partial fat replacer and the lipid profile was modified as a decrease in the n6/n3 ratio (11.59 to 9.50), and atherogenic and trombogenic index (from 0.42 to 0.27 and 0.94 to 0.56 respectively) was observed. Beef patties were added with two MRP levels (1% w/w and 3% w/w). Patties with no antioxidants were used as control and patties containing 0.01% w/w of butylhydroxyanisole (BHA) were used as reference. Oxidative stability of refrigerated vacuum-packed patties was evaluated during 15 days of storage. Results showed 3% of MRP as the most appropriate concentration to prevent lipid oxidation with inhibition percentages of 75%, and 9 days as the limit time of chilled storage regarding consumers’ perceptions.展开更多
文摘Over the last 30 years,China’s small commodity market has been a big driving force for economic growth,and the city of Yiwu is the largest small commodity market in China.Its stong vitality today gives us a picture into how China’s economy remains so strong.
文摘With the gradual recovery of the global economy,China's rare earth import and export trade has resumed growth.In 2023,China's total import and export of various rare earths and rare earth magnetic materials reached 290,000 tons,a year-on-year increase of 24%.However,due to the decline in rare earth commodity prices.
基金supported by the Ministry of Higher Education Malaysia (MOHE)through the Fundamental Research Grant Scheme (FRGS),FRGS/1/2022/STG06/USM/02/11 and Universiti Sains Malaysia.
文摘Rubber producers,consumers,traders,and those who are involved in the rubber industry face major risks of rubber price fluctuations.As a result,decision-makers are required to make an accurate estimation of the price of rubber.This paper aims to propose hybrid intelligent models,which can be utilized to forecast the price of rubber in Malaysia by employing monthly Malaysia’s rubber pricing data,spanning from January 2016 to March 2021.The projected hybrid model consists of different algorithms with the symbolic Radial Basis Functions Neural Network k-Satisfiability Logic Mining(RBFNN-kSAT).These algorithms,including Grey Wolf Optimization Algorithm,Artificial Bee Colony Algorithm,and Particle Swarm Optimization Algorithm were utilized in the forecasting data analysis.Several factors,which affect the monthly price of rubber,such as rubber production,total exports of rubber,total imports of rubber,stocks of rubber,currency exchange rate,and crude oil prices were also considered in the analysis.To evaluate the results of the introduced model,a comparison has been conducted for each model to identify the most optimum model for forecasting the price of rubber.The findings showed that GWO with RBFNN-kSAT represents the most accurate and efficient model compared with ABC with RBFNNkSAT and PSO with RBFNN-kSAT in forecasting the price of rubber.The GWO with RBFNN-kSAT obtained the greatest average accuracy(92%),with a better correlation coefficient R=0.983871 than ABC with RBFNN-kSAT and PSO with RBFNN-kSAT.Furthermore,the empirical results of this study provided several directions for policymakers to make the right decision in terms of devising proper measures in the industry to address frequent price changes so that the Malaysian rubber industry maintains dominance in the international markets.
文摘Health Products and Technologies (HPTs) are pivotal for an efficient health system. Availability and accessibility to affordable health products are critical indicators towards achieving universal health coverage. Routine supportive supervision, performance monitoring, recognition of efforts and client feedback are vital activities toward health supply chain system strengthening. This is a descriptive paper that describes a model of integrated commodity supportive supervision, and mentorship and its impact on various outcomes of health commodity management. Data were abstracted from the standardized scored checklists used during integrated commodity supportive supervision and supply chain audit in public health facilities in Vihiga County. Scores for the period 2020 to 2022 were analyzed on the eight key areas of interest. The analysis was done using Statistical Package for Social Sciences (SPSS version 26). Results are interpreted at 95% Confidence interval. This paper also shares findings from both quantitative and qualitative data from client exit and facility managers’ interviews. Six complete rounds of supervisions, three clients and service providers’ interviews, and three annual award events have been conducted. We observed trends across six data collections points and compared the results at first point or baseline (January-June 2020) to the results at the last point or end line (April-June 2022). Findings show significant improvements on the eight parameters in terms of mean scores as follows: resolution of issues from previous visits by 35.06% (46.75% - 81.81%);storage of HPTs by 17.41% (68.72% - 86.13%);inventory management by 28.16% (42.67% - 70.83%);availability and use of commodity data management information systems (MIS) tools by 22.39% (74.40% - 96.79%);verification of commodity data by 25.61% (65.56% - 91.17%);availability of guidelines and job aids for commodity management by 46.28% (36.65% - 82.93%). There was an improvement on the mean score on accountability by 20.22% (58.58% - 83.51%). The composite (final) score improved by 28.33% (56.19% - 84.52%). There was progressive narrowing of the standard deviations on all the indicators across the study period. This demonstrates that there is standardization of practices and positive competition among all the public health facilities. There were significant improvements on all the eight indicators. Routine integrated commodity supportive supervision has proven to be an effective high impact intervention in improving management of health products and technologies in Vihiga County, Kenya.
文摘According to OECD standards(United Nations,2008),“productivity is commonly defined as a ratio of a volume measure of output to a volume measure of input use”.This ratio indicates how efficiently production inputs,such as labour and capital,are being used in an economy to produce a given level of outputs.Productivity stays aside the main aggregates of national accounts,as the national income(a proxy of GDP),the total output and the circulating capital.Assume the existence of a Leontief-type national Input-Output Table with the vector of total output and the vector of intermediate inputs,situated on its right and lower border.In this paper a measure of capital productivity is proposed.It is called the productiveness,and results from the solution of a boundary value problem,elaborated for Input-Output Tables,involving the vector of total output and the vector of intermediate inputs.
文摘Nowadays,the carbon markets in the world have increasingly matured and carbon trading have flourished in China.In the framework of carbon trading,the carbon emission right has become a tradable special commodity,and it has financial feature and asset feature.Relying on the business entities,carbon assets management joins up the virtual carbon emission right,financial capital and real economy,restructures existing carbon resources of enterprises and impacts the current international economic pattern.At present,however,the carbon assets management systems and market rules of our country remains to be perfect.How to increase the efficiency of carbon asset management,how to further improve the carbon management,how to further improve the carbon asset management method and mechanism have become the common issue of China’s academia and practice.
文摘The present study aims to analyze the growing Sino-Brazilian trade relationship and how China has contributed to the commodity price boom in the recent period.Throughout the article,it was possible to identify that the export and import agenda between countries differs in terms of number of products and technological intensity,so that imported products are capital intensive,while exported products are predominantly commodities.The text is divided into two main sections,firstly addressing the literature review on the commodities boom and highlighting the“China effect”.The second section analyzes trade between the countries,so that the trade relationship has followed an increasing trajectory since 2003.As of 2009,China has become Brazil’s main trading partner,surpassing historical partners such as the United States and Argentina.
文摘Nini Dog of Huaiyang County,one of the provincial-level intangible cultural heritage of Henan,has high artistic,cultural and archaeological value.It is proposed that protection and inheritance of national cultures,as well as innovation based on the inheritance are of great significance to improve the marketing and economic efficiency of these cultures.On this basis,the necessity of further development of Nini Dog commodities is analyzed,which is the need of both tourism development and its own development.This study through full investigation gives the orientation of Nini Dog commodities,potential consumers are classified into 3 groups:people interested in traditional cultures,tourists and children;consumer psychology is analyzed and then design orientation of Nini Dog is proposed,it is stressed that identity design should be enhanced to establish brands,creative commodity design promoted to explore new development thoughts,and composite design encouraged to expand the market.By doing this,the study aims at providing design and development guidance for the future development of Nini Dog commodities.
文摘Objective:To report demographic and injury characteristics of tendo-Achilles(TA)injury,and determine its association with the use of Indian style commode seat(ISCS),the clinical and functional outcomes.Methods:This observational study was conducted between 1 January 2016 and 31 December 2019,and a total of 44 patients with TA injury were included in the study.Their demographic profile,etiology,operative details,and functional outcomes were studied.All patients underwent primary repair followed by standard postoperative management and follow-up for 6 months.Results:Out of 44 patients,7(15.9%)sustained closed injuries while 37(84.1%)sustained open injuries.In open injury cases,30(81%)patients suffered an injury due to slipping in ISCS,4(11%)from road traffic accidents,and 3(8%)due to falling of a heavy object.Besides,20.45%of cases of ISCS injury had associated neurovascular injury.Twenty(45%)patients took more than 90 days to start independent ambulation.At 6 months follow-up,no one could reach pre-injury fitness status.Conclusions:Open TA injury by ISCS is an important,under-reported,and preventable cause of loss of physically active manpower in institutional setups.
基金supported by the National Key R&D Program of China (No. 2021YFA1501700)the Funding for Hundred Talent Program B of Sichuan University (20822041E4079)+2 种基金the Institutional Research Fund from Sichuan University (2020SCUNL205)the State Key Laboratory of Polymer Materials Engineering Open Fund project (sklpme2020-1-02)the Fundamental Research Funds for the Central Universities。
文摘Of all the existing materials, plastics are no doubt among the most versatile ones. However, the extreme increases in plastic production as well as the difficulty of the material for degradation have led to a huge number of plastic wastes. Their recycling rate after disposal is less than 10%, resulting in a series of serious environmental and ecological problems as well as a significant waste of resources. Current recycling methods generally suffer from large energy consumption, the low utilization rate of recycled products with low added value, and produce other waste during the process. Here, we summarized recentlydeveloped chemical recycling ways on commodity plastics, especially new catalytic paths in production of fuels, high-valued chemicals and advanced materials from a single virgin or a mixture of plastic waste,which have emerged as promising ways to valorize waste plastics more economically and environmentally friendly. The new catalyst design criteria as well as innovative catalytic paths and technologies for plastic upcycling are highlighted. Beyond energy recovery by incineration, these approaches demonstrate how waste plastics can be a viable feedstock for energy use with the generation of clean H_(2), high-quality liquid fuels and materials for energy storage, and help inspiring more catalytic process on plastic upcycling to overcome the economical hurdle and building a circular plastic economy.
文摘Fluctuations in commodity prices should influence mining operations to continually update and adjust their mine plans in order to capture additional value under new market conditions. One of the adjustments is the change in production sequencing. This paper seeks to present a method for quantifying the net present value(NPV) that may be directly attributed to the change in commodity prices. The evaluation is conducted across ten copper price scenarios. Discrete event simulation combined with mixed integer programming was used to attain a viable production strategy and to generate optimal mine plans. The analysis indicates that an increase in prices results in an increased in the NPV from$96.57M to $755.65M. In an environment where mining operations must be striving to gain as much value as possible from the rights to exploit a finite resource, it is not appropriate to keep operating under the same mine plan if commodity prices alter during the course of operations.
基金Supported by Science and Technology Research and Development Program of Chengde City in 2011(201121167)
文摘[ Objective] The paper was to screen out ideal biological pesticides, in order to provide guidance for pollution-free control against Pieris rapae Linne. [Method] Taking Chinese cabbage variety Taiyuan Erqing as the test material, the field control efficiencies of four pesticides including PrGV · Bt WP 1 000 times dilution, NPV · Bt SC 750 times dilution, 0.5% azadirachtin EC 750 times dilution, and 0.3% matrine AS 500 times dilution against P. rapae were studied, and their impacts on yield and planting benefits of Chinese cabbage were also determined. Using foliar spray method, the pesticides were sprayed for the first time when the second or third instar larvae of P. rapae first occurred in fields, and sprayed for the second time with the interval of 15 d. The fields sprayed with beta-cypermethrin EC (organic chemical pesticide) and water were set as control. [ Result] NPV · Bt SC 750 times dilution had the best effect after spraying for two times: the control efficiency against P. rapae at 15 d after spraying was 90.11% ; the damage rate of Chinese cabbage was only 0.21%, while the commodity rate reached 100% ; compared with chemical pesticide spraying, the commodity yield (177 262.5 kg/hm2 ) and the income after deducting spraying cost (48 858.5 yuan/hm2 ) were increased by 14.7% and 13.75%, respectively. [ Conclusion] Although biological pesticides are more expensive, they have long persistence and good control effect, resulting in green and safe Chinese cabbage with high commodity rate and yield, and higher eventual economic benefit after deducting spraying cost.
文摘Forecasting mineral commodity(MC) prices has been an important and difficult task traditionally addressed by econometric, stochastic-Gaussian and time series techniques. None of these techniques has proved suitable to represent the dynamic behavior and time related nature of MC markets. Chaos theory(CT) and machine learning(ML) techniques are able to represent the temporal relationships of variables and their evolution has been used separately to better understand and represent MC markets. CT can determine a system's dynamics in the form of time delay and embedding dimension. However, this information has often been solely used to describe the system's behavior and not for forecasting.Compared to traditional techniques, ML has better performance for forecasting MC prices, due to its capacity for finding patterns governing the system's dynamics. However, the rational nature of economic problems increases concerns regarding the use of hidden patterns for forecasting. Therefore, it is uncertain if variables selected and hidden patterns found by ML can represent the economic rationality.Despite their refined features for representing system dynamics, the separate use of either CT or ML does not provide the expected realistic accuracy. By itself, neither CT nor ML are able to identify the main variables affecting systems, recognize the relation and influence of variables though time, and discover hidden patterns governing systems evolution simultaneously. This paper discusses the necessity to adapt and combine CT and ML to obtain a more realistic representation of MC market behavior to forecast long-term price trends.
文摘This work aimed to develop a healthier meat product, by improving nutritional properties related to lipid profile, using a Maillard reaction product (MRP) obtained from recycling blood from local slaughterhouses as antioxidant. Soybean oil was used as partial fat replacer and the lipid profile was modified as a decrease in the n6/n3 ratio (11.59 to 9.50), and atherogenic and trombogenic index (from 0.42 to 0.27 and 0.94 to 0.56 respectively) was observed. Beef patties were added with two MRP levels (1% w/w and 3% w/w). Patties with no antioxidants were used as control and patties containing 0.01% w/w of butylhydroxyanisole (BHA) were used as reference. Oxidative stability of refrigerated vacuum-packed patties was evaluated during 15 days of storage. Results showed 3% of MRP as the most appropriate concentration to prevent lipid oxidation with inhibition percentages of 75%, and 9 days as the limit time of chilled storage regarding consumers’ perceptions.