Site conditions and species identity have a combined effect on fine root growth of trees in pure and mixed stands.However,mechanisms that may contribute to this effect are rarely studied,even though they are essential...Site conditions and species identity have a combined effect on fine root growth of trees in pure and mixed stands.However,mechanisms that may contribute to this effect are rarely studied,even though they are essential to assess the potential of species to cope with climate change.This study examined fine root overlap and the linkage between fine root and stem growth of European beech(Fagus sylvatica)growing in pure and mixed stands with Douglas fir(Pseudotsuga menziesii)or Norway spruce(Picea abies)at two different study sites in northwestern Germany.The study sites represented substantially different soil and climate conditions.At each site,three stands,and at each stand,three pairs of trees were studied.In the pure beech stand,the pairs consisted of two beech trees,while in the mixed stands each pair was composed of a beech tree and a conifer.Between each pair,three evenly spaced soil cores were taken monthly throughout the growing season.In the pure beech stands,microsatellite markers were used to assign the fine roots to individual trees.Changes in stem diameter of beech were quantified and then upscaled to aboveground wood productivity with automatic high-resolution circumference dendrometers.We found that fine root overlap between neighboring trees varied independently of the distance between the paired trees or the stand types(pure versus mixed stands),indicating that there was no territorial competition.Aboveground wood productivity(wood NPP)and fine root productivity(root NPP)showed similar unimodal seasonal patterns,peaking in June.However,this pattern was more distinct for root NPP,and root NPP started earlier and lasted longer than wood NPP.The influence of site conditions on the variation in wood and root NPP of beech was stronger than that of stand type.Wood NPP was,as expected,higher at the richer site than at the poorer site.In contrast,root NPP was higher at the poorer than at the richer site.We concluded that beech can respond to limited resources not only above-but also belowground and that the negative relationship between above-and belowground growth across the study sites suggests an‘optimal partitioning’of growth under stress.展开更多
With economic progress and the continuous advancement of science and technology,the issue of employees substituting punch cards has gradually become a significant challenge in enterprise management.The purpose of this...With economic progress and the continuous advancement of science and technology,the issue of employees substituting punch cards has gradually become a significant challenge in enterprise management.The purpose of this paper is to discuss the causes,effects,and countermeasures of the employee punch card phenomenon,with the aim of providing effective management recommendations for Chinese enterprises.In practice,enterprises should flexibly apply the countermeasures proposed in this paper according to their specific circumstances to prevent substitute punch card incidents and improve overall management efficiency.展开更多
AIM:To estimate the cost-benefit of endoscopic screening strategies of esophageal cancer(EC)in high-risk areas of China. METHODS:Markov model-based analyses were conducted to compare the net present values(NPVs)and th...AIM:To estimate the cost-benefit of endoscopic screening strategies of esophageal cancer(EC)in high-risk areas of China. METHODS:Markov model-based analyses were conducted to compare the net present values(NPVs)and the benefit-cost ratios(BCRs)of 12 EC endoscopic screening strategies.Strategies varied according to the targeted screening age,screening frequencies,and follow-up intervals.Model parameters were collected from population-based studies in China,published literatures,and surveillance data. RESULTS:Compared with non-screening outcomes,all strategies with hypothetical 100 000 subjects saved life years.Among five dominant strategies determined by the incremental cost-effectiveness analysis,screening once at age 50 years incurred the lowest NPV(international dollar-I$55 million)and BCR(2.52).Screening six times between 40-70 years at a 5-year interval[i.e., six times(40)f-strategy]yielded the highest NPV(I$99 million)and BCR(3.06).Compared with six times(40)fstrategy,screening thrice between 40-70 years at a 10-year interval resulted in relatively lower NPV,but the same BCR. CONCLUSION:EC endoscopic screening is cost-beneficial in high-risk areas of China.Policy-makers should consider the cost-benefit,population acceptance,and local economic status when choosing suitable screening strategies.展开更多
Over 50 years ago, banana export plantations in Panama were ruined by Fusarium wilt race 1 (Foc. R1) since the popular cultivar Gros Michel is susceptible to Foc. R1 [1]. Fortunately, the resistant cultivar Cavendish ...Over 50 years ago, banana export plantations in Panama were ruined by Fusarium wilt race 1 (Foc. R1) since the popular cultivar Gros Michel is susceptible to Foc. R1 [1]. Fortunately, the resistant cultivar Cavendish replaced Gros Michel as the world biggest commercial fruit after ten years’ research and development. Due to its good economic profit, banana industry develops very fast recently in China. Unfortunately, Fusarium oxysporum f. sp. cubense tropical race 4 (TR4) brought disaster to Cavendish plantation since 1996. Most of traditional banana planting zones of Guangdong and Hainan provinces were infected by Foc. TR4 to the end of 2009. In order to fight against Foc. TR4, here we tried to investigate the cost-benefit and disease resistance of six banana cultivars (Cavendish Baxijiao, Dajiao, Guangfen No. 1, Fenzha No. 1, Gongjiao, Haigongjiao) planted in China Foc. Zones. Comparisons were conducted on their economic characteristics, cost, benefit, as well as the advantage and disadvantage and their application in rota-tion. Generally, supposing the investment of $ 4400/ha, the banana plantation attains a good economic profit as $ 2200/ha. Rotation of these cultivars can maintain the biodiversity as well as improve the sustainable development of banana industry.展开更多
Determining the optimal timing is the core of preventive maintenance. Highway agencies always face with the challenge of determining optimal timing for preventive maintenance, particularly in China where there are no ...Determining the optimal timing is the core of preventive maintenance. Highway agencies always face with the challenge of determining optimal timing for preventive maintenance, particularly in China where there are no condition indicators designed for determining adequate timing for applying preventive maintenance and little literature relating to the development of pavement performance. This work presented the indicators, including crack ratio (Rc), rutting depth (DR), international roughness index (IIR) and sideway force coefficient (CsF) to determine the adequate timing for preventive maintenance in China. The proper ranges of each indicator to apply to preventive maintenance were then recommended. They are 0.28%-1.4% for Rc, 10-15 mm for DR, 1.97-3.5 for lrR, 40--50 for CSF. Based on pavement condition survey data collected on the test roads in Hebei Province, China, on the application of slurry seal at different timings, the pavement performance was established and the adequate timings for applying slurry seal was studied. Based on benefit-cost analysis, it is suggested that the fourth year is the optimal timing for applying slurry seal based on the condition in China. A framework is established to determine the adequate timings of applying other preventive maintenance methods.展开更多
The purpose of this study is to explore whether it is worthwhile to launch a routine diabetic retinopathy (DR) screening for blindness pre-vention among Chinese type 2 diabetes from different perspective based on the ...The purpose of this study is to explore whether it is worthwhile to launch a routine diabetic retinopathy (DR) screening for blindness pre-vention among Chinese type 2 diabetes from different perspective based on the popula-tion-based study in Kinmen, Taiwan. A total of 971 community dwelling adults previously di-agnosed with type 2 diabetes in 1991-1993 un-derwent DR screening in 1999-2002 by a panel of ophthalmologists using on-site indirect oph-thalmoscopy and 45-degree color fundus retinal photographs. The cost-benefit analysis is used to evaluate the DR screening. In terms of bene-fit-cost ratio, the different screening programs for DR could save New Taiwan Dollars (NTD) from 14.38 to 36.83 in discounted costs for each dollar incurred in different screening years from the societal viewpoint for Taiwan and save NTD from 0.81 to 1.80 in different screening years from health care payer’s perspective. The av-erage estimate of willingness-to-pay to translate into benefit yields NTD from 937.8 to 4,689 be- nefits per case due to DR screening in different screening years during 10-year follow-up. The net present value of the DR screening were NTD from -167,318 to -307,251.2 in different screening years. In conclusion, it is worthwhile to initial a routine DR screening of Chinese type 2 diabetes for blindness prevention from the societal per-spective but not from consumer decision based on the willingness-to-pay perspective.展开更多
Ecological and environmental issues have always been the focus of government work. The economic losses caused by air pollution,water pollution,noise pollution and solid waste pollution caused by land use development p...Ecological and environmental issues have always been the focus of government work. The economic losses caused by air pollution,water pollution,noise pollution and solid waste pollution caused by land use development projects are estimated,and the total population economic losses are incorporated into project costing. Using the analytic hierarchy process,four benefit indicators and five cost indicators are selected for constructing a fuzzy comprehensive evaluation model to evaluate the cost-benefit of projects of different scales. The projects of different scales are ranked according to the level of comprehensive scores. The results show that large-scale projects are cost-effective and stable over the long term,and there are differences in the main sources of pollution-caused economic losses for projects of different scales. At last,reasonable policy suggestions are made to relevant planning and management personnel.展开更多
In this in-depth exploration, I delve into the complex implications and costs of cybersecurity breaches. Venturing beyond just the immediate repercussions, the research unearths both the overt and concealed long-term ...In this in-depth exploration, I delve into the complex implications and costs of cybersecurity breaches. Venturing beyond just the immediate repercussions, the research unearths both the overt and concealed long-term consequences that businesses encounter. This study integrates findings from various research, including quantitative reports, drawing upon real-world incidents faced by both small and large enterprises. This investigation emphasizes the profound intangible costs, such as trade name devaluation and potential damage to brand reputation, which can persist long after the breach. By collating insights from industry experts and a myriad of research, the study provides a comprehensive perspective on the profound, multi-dimensional impacts of cybersecurity incidents. The overarching aim is to underscore the often-underestimated scope and depth of these breaches, emphasizing the entire timeline post-incident and the urgent need for fortified preventative and reactive measures in the digital domain.展开更多
A tool for calculating the economic and environmental impacts of the use of byproducts of industrial processes that can substitute for perishable resources was presented.This was exemplified by fly ash(the fine fracti...A tool for calculating the economic and environmental impacts of the use of byproducts of industrial processes that can substitute for perishable resources was presented.This was exemplified by fly ash(the fine fraction of ash originating from coal burned to generate electricity and collected by filtering exhaust gases leaving the furnace),added to soil as a component of sewage sludge stabilized with fly ash and lime(NVS).Application to soil of NVS has potential agricultural and environmental advantages and disadvantages.The costs and benefits of such application were calculated using both a database and expert opinions.The calculations assumed a representative assemblage of soils and crops,with weights assigned to each crop type and soil characteristic.The annual weighted benefits(additional income for the farmer)and costs per hectare reached 324$/ha and 131$/ha respectively.Major potential benefits include:Chemical fertilizer replacement,159$/ha;Improvement to the soil’s physical properties,75$/ha;Supply of vital trace elements,33$/ha.Major potential costs were:Regulatory limitations on marketing of crops pending proof of absence of risk of heavy metals or radionuclides accumulation in these crops,(17$/ha and 36$/ha respectively);Application and incorporation cost,50$/ha.The presented estimates of the costs and benefits refer to the array of soils and conditions typical to Israel.It is possible to maximize potential benefits by applying fly ash only to the most suitable agricultural soils while improper use of fly ash will increase the costs incurred from its use.展开更多
Owing to high costs and unnecessary inspections necessitated by the traditional inspection planning for ship structures, the risk-based inspection and repair planning should be investigated for the most cost-effective...Owing to high costs and unnecessary inspections necessitated by the traditional inspection planning for ship structures, the risk-based inspection and repair planning should be investigated for the most cost-effective inspection. This paper aims to propose a cost-benefit assessment model of risk-based inspection and repair planning for ship structures subjected to corrosion deterioration. Then, the benefit-cost ratio is taken to be an index for the selection of the optimal inspection and repair strategy. The planning problem is formulated as an optimization problem where the benefit-cost ratio for the expected lifetime is maximized with a constraint on the minimum acceptalbe reliability index. To account for the effect of corrosion model uncertainty on the cost-benefit assessment, two corrosion models, namgly, Paik' s model and Guedes Soares' model, are adopted for analysis. A numerical example is presented to illustrate the proposed method. Sensitivity studies are also providet. The results indicate that the proposed method of risk-based cost-benefit analysis can effectively integrate the economy with reliability of the inspection and repair planning. A balance can be achieved between the risk cost and total expected inspection and repair costs with the proposed method, which is very. effective in selecting the optimal inspection and repair strategy. It is pointed out that the corrosion model uncertainty and parametric uncertaintg have a significant impact on the cost-benefit assessment of inspection and repair planning.展开更多
Objective Phenylketonuria (PKU) and congenital hypothyroidism (CH) are common diseases thatare associated with mental retardation. In order to make the best use of health care resources to achieve themaximum social an...Objective Phenylketonuria (PKU) and congenital hypothyroidism (CH) are common diseases thatare associated with mental retardation. In order to make the best use of health care resources to achieve themaximum social and economic benefits and to lay the foundation for the popularization of neonatal screening, acost- benefit analysis of neonatal screening program was undertaken. Methods Based on screening results,medical history and the data published by the national statistic departments. Results Our result shows that it islairly profitable to conduct neonatal screening in China: the cost - benejit ratio for PKU screenging is 1:3.7, andthe cost-benefit ratio for CH screening is 1:3.6. Conclusion This report therefore strongly suPPorts furtherpopularization of neonatal screening in China.展开更多
On the basis of market demand survey of chestnut,this article carries out cost-benefit analysis of the chestnut production in Xingtai County,to understand the profitability and payback period of local chestnut product...On the basis of market demand survey of chestnut,this article carries out cost-benefit analysis of the chestnut production in Xingtai County,to understand the profitability and payback period of local chestnut production.It points out that chestnut production has a high rate of return on investment,and chestnut can be promoted on a large scale in Xingtai County.However,there are still some problems in the production and marketing of chestnut in Xingtai County,such as low level of technology,extensive management,low level of organization,market imperfections and weak brand consciousness.Based on these problems,corresponding recommendations are put forth.展开更多
According to the relevant statistical data in National Agricultural cost-benefit Data Compilation(2001- 2013),we use the modified entropy weight- TOPSIS model to research the cost-benefit status of scale pig breeding ...According to the relevant statistical data in National Agricultural cost-benefit Data Compilation(2001- 2013),we use the modified entropy weight- TOPSIS model to research the cost-benefit status of scale pig breeding in Shandong Province from the perspective of comparing it with that of the entire country and 9 other main pig producing areas. The results show that compared with the national average,the cost-benefit ratio of small scale pig breeding in Shandong Province is lower,while the cost-benefit ratio of medium scale and large scale pig breeding is significantly improved; the cost-benefit ratio of small scale pig breeding in Shandong Province is basically the same as that in 9 other main pig producing areas,while the cost-benefit ratio of medium scale and large scale pig breeding is higher; the output value of main products and the purchase price of piglet are two major bottlenecks restricting the cost-benefit improvement of scale pig breeding in Shandong Province.展开更多
With the rapid economic development of China,the environmental degradation brought by economic development cannot be ignored.In order to measure the cost of environmental degradation brought by land projects in the pr...With the rapid economic development of China,the environmental degradation brought by economic development cannot be ignored.In order to measure the cost of environmental degradation brought by land projects in the process of economic development and evaluate a land project,this paper establishes an ecological service evaluation model based on cost-benefit method to analyze the cost and benefit of land development projects from a new perspective,and explore effective strategies to alleviate environmental degradation.展开更多
With the introduction of many derivatives into the capital market,including stock index futures,the trading strategies in financial markets have been gradually enriched.However,there is still no theoretical model that...With the introduction of many derivatives into the capital market,including stock index futures,the trading strategies in financial markets have been gradually enriched.However,there is still no theoretical model that can determine whether these strategies are effective,what the risks are,and how costly the strategies are.We built an agent-based cross-market platform that includes five stocks and one stock index future,and constructed an evaluation system for stock index futures trading strategies.The evaluation system includes four dimensions:effectiveness,risk,occupation of capital,and impact cost.The results show that the informed strategy performs well in all aspects.The risk of the technical strategy is relatively higher than that of the other strategies.Moreover,occupation of capital and impact cost are both higher for the arbitrage strategy.Finally,the wealth of noise traders is almost lost.展开更多
Motor vehicle inspection and maintenance (I/M) programs are designed to identify high-emitting vehicles and mitigate their impacts on air quality and climate. I/M programs have been traditionally ranked superior among...Motor vehicle inspection and maintenance (I/M) programs are designed to identify high-emitting vehicles and mitigate their impacts on air quality and climate. I/M programs have been traditionally ranked superior among various vehicle emission control measures by the results of cost-benefit analysis, based on the assumption that these programs will achieve the targeted emission reduction outcomes. However, the actual effects of I/M programs may be greatly uncertain and when this uncertainty is taken into account, these programs may become suboptimal. This study develops a new a cost-benefit analysis framework that links various program design consideration, such as program participation rate, identification rate and effective repair rate, to the public health benefits as well as costs of the programs. This framework helps decision makers to investigate minimum implementation requirements that at least ensure the benefits are greater than the costs of implementing the programs in order to improve the overall effectiveness of the I/M programs. To illustrate the applications of the framework, it was applied to a particulate matter oriented I/M program targeting all diesel-fueled vehicles in the city of Bangkok, Thailand, a large metropolitan area that has been suffering from severe ambient PM pollution mainly attributable to its wide use of diesel-fueled vehicles and motorcycles. It was found that the health benefits achieved from the program are sensitive to several key program design elements, including participation rate and problem vehicle identification rate, fraction of effective repairs and illegal operation rate. Other variables, such as the testing cut-points and vehicle population growth rate, only have modest effects on the overall emission reduction and consequent health benefits. Overall, the performance of multiple variables associated with I/M program design needs to be improved simultaneous in order to achieve the targeted benefits of the program.展开更多
From the point of cost-benefit flow and with the Six Green Projects in China as the case and background, it is criticized that the current natural resource and environmental management and the policies in China have s...From the point of cost-benefit flow and with the Six Green Projects in China as the case and background, it is criticized that the current natural resource and environmental management and the policies in China have some problems unsolved since the model of cost-benefit flow is still centralized and mainly in an administrative way in spite of many efforts made theoretically and practically. It is suggested that a new model based on market-oriented economy from the point of cost-benefit flow with Six Green Projects Management and Policies System consist of complete natural reserve (NR). Management system included environmental nature reserves in addition to biodiversity nature reserve, paid using nature resources, an environmental conservation and construction industry and renewable resource production incentive system that turn the direct administration and operation to management and services. The detail figure of the new model of cost-benefit flow is provided and the main points related are discussed in this paper.展开更多
The objective was to assess the impact on health due to the exposure to air pollution derived from the renewal of the urban bus fleet in S?o Paulo. The study analyzed the substitution of the bus fleet through the vari...The objective was to assess the impact on health due to the exposure to air pollution derived from the renewal of the urban bus fleet in S?o Paulo. The study analyzed the substitution of the bus fleet through the variation of the concentration of atmospheric pollutants such as PM10 in the municipality of S?o Paulo and its associated health’s benefits values compared to the investments performed in the bus fleet renewal. PM10 average annual reduction due to the bus improvement system resulted on 22.3%. A cost-benefit evaluation considered the renewal investments’ costs compared to the obtained valued health benefits and it resulted in 4.31. Although the result may suggest a not viable investment, it must be observed that air pollution reduction favors health impacts and that this relation could be improved if additional investments on sustainable transportation increase.展开更多
Within the inventory era, urban shrinkage characterized by economic decline and space decay has been widely witnessed in China. The modes and trajectories of urban redevelopment have thus become areas of major concern...Within the inventory era, urban shrinkage characterized by economic decline and space decay has been widely witnessed in China. The modes and trajectories of urban redevelopment have thus become areas of major concern for both policymakers and scholars. Taking the multi-actor participation nature of redevelopment, this paper stemming from the game-theoretical approach demonstrates in empirical terms on two major fronts. First, the redevelopment of industrial land without the transfer of land use right is shown to be deadlocked by the incapacitation of the original land-user and unlocked with the participation of the new developer. Second, the preference of the original land-user to maximize its interests by operating by itself rather than continue to cooperate with the new developer is observed in the post-redevelopment stage. Therein, the entrepreneurial local government acts only as a “mediator” between the two market entities and tends not to directly intervene in their cooperation. Thus that, it is the reasonable distribution of potential benefits or the pricing of different rights in the land property right bundle rather than their definition that matters more for land redevelopment. Because the delineation of land property rights has never been a problem in a mature land market, particularly for stock industrial land.展开更多
基金part of the Research Training Group 2300,funded by the German research funding organization (Deutsche Forschungsgemeinschaft-DFG) Grand id:316045089
文摘Site conditions and species identity have a combined effect on fine root growth of trees in pure and mixed stands.However,mechanisms that may contribute to this effect are rarely studied,even though they are essential to assess the potential of species to cope with climate change.This study examined fine root overlap and the linkage between fine root and stem growth of European beech(Fagus sylvatica)growing in pure and mixed stands with Douglas fir(Pseudotsuga menziesii)or Norway spruce(Picea abies)at two different study sites in northwestern Germany.The study sites represented substantially different soil and climate conditions.At each site,three stands,and at each stand,three pairs of trees were studied.In the pure beech stand,the pairs consisted of two beech trees,while in the mixed stands each pair was composed of a beech tree and a conifer.Between each pair,three evenly spaced soil cores were taken monthly throughout the growing season.In the pure beech stands,microsatellite markers were used to assign the fine roots to individual trees.Changes in stem diameter of beech were quantified and then upscaled to aboveground wood productivity with automatic high-resolution circumference dendrometers.We found that fine root overlap between neighboring trees varied independently of the distance between the paired trees or the stand types(pure versus mixed stands),indicating that there was no territorial competition.Aboveground wood productivity(wood NPP)and fine root productivity(root NPP)showed similar unimodal seasonal patterns,peaking in June.However,this pattern was more distinct for root NPP,and root NPP started earlier and lasted longer than wood NPP.The influence of site conditions on the variation in wood and root NPP of beech was stronger than that of stand type.Wood NPP was,as expected,higher at the richer site than at the poorer site.In contrast,root NPP was higher at the poorer than at the richer site.We concluded that beech can respond to limited resources not only above-but also belowground and that the negative relationship between above-and belowground growth across the study sites suggests an‘optimal partitioning’of growth under stress.
文摘With economic progress and the continuous advancement of science and technology,the issue of employees substituting punch cards has gradually become a significant challenge in enterprise management.The purpose of this paper is to discuss the causes,effects,and countermeasures of the employee punch card phenomenon,with the aim of providing effective management recommendations for Chinese enterprises.In practice,enterprises should flexibly apply the countermeasures proposed in this paper according to their specific circumstances to prevent substitute punch card incidents and improve overall management efficiency.
基金Supported by The National Science and Technology Pillar Program of the 11th National Five-Year Plan of China,No. 2006BAI02A15
文摘AIM:To estimate the cost-benefit of endoscopic screening strategies of esophageal cancer(EC)in high-risk areas of China. METHODS:Markov model-based analyses were conducted to compare the net present values(NPVs)and the benefit-cost ratios(BCRs)of 12 EC endoscopic screening strategies.Strategies varied according to the targeted screening age,screening frequencies,and follow-up intervals.Model parameters were collected from population-based studies in China,published literatures,and surveillance data. RESULTS:Compared with non-screening outcomes,all strategies with hypothetical 100 000 subjects saved life years.Among five dominant strategies determined by the incremental cost-effectiveness analysis,screening once at age 50 years incurred the lowest NPV(international dollar-I$55 million)and BCR(2.52).Screening six times between 40-70 years at a 5-year interval[i.e., six times(40)f-strategy]yielded the highest NPV(I$99 million)and BCR(3.06).Compared with six times(40)fstrategy,screening thrice between 40-70 years at a 10-year interval resulted in relatively lower NPV,but the same BCR. CONCLUSION:EC endoscopic screening is cost-beneficial in high-risk areas of China.Policy-makers should consider the cost-benefit,population acceptance,and local economic status when choosing suitable screening strategies.
文摘Over 50 years ago, banana export plantations in Panama were ruined by Fusarium wilt race 1 (Foc. R1) since the popular cultivar Gros Michel is susceptible to Foc. R1 [1]. Fortunately, the resistant cultivar Cavendish replaced Gros Michel as the world biggest commercial fruit after ten years’ research and development. Due to its good economic profit, banana industry develops very fast recently in China. Unfortunately, Fusarium oxysporum f. sp. cubense tropical race 4 (TR4) brought disaster to Cavendish plantation since 1996. Most of traditional banana planting zones of Guangdong and Hainan provinces were infected by Foc. TR4 to the end of 2009. In order to fight against Foc. TR4, here we tried to investigate the cost-benefit and disease resistance of six banana cultivars (Cavendish Baxijiao, Dajiao, Guangfen No. 1, Fenzha No. 1, Gongjiao, Haigongjiao) planted in China Foc. Zones. Comparisons were conducted on their economic characteristics, cost, benefit, as well as the advantage and disadvantage and their application in rota-tion. Generally, supposing the investment of $ 4400/ha, the banana plantation attains a good economic profit as $ 2200/ha. Rotation of these cultivars can maintain the biodiversity as well as improve the sustainable development of banana industry.
基金Project(IRT1050) supported by Program for Changjiang Scholars and Innovative Research Team in University, ChinaProject (2009318000027) supported by Ministry of Transport of ChinaProject(CHD2011TD002) supported by the Special Fund for Basic Scientific Research of Central Colleges, Chang’an University, China
文摘Determining the optimal timing is the core of preventive maintenance. Highway agencies always face with the challenge of determining optimal timing for preventive maintenance, particularly in China where there are no condition indicators designed for determining adequate timing for applying preventive maintenance and little literature relating to the development of pavement performance. This work presented the indicators, including crack ratio (Rc), rutting depth (DR), international roughness index (IIR) and sideway force coefficient (CsF) to determine the adequate timing for preventive maintenance in China. The proper ranges of each indicator to apply to preventive maintenance were then recommended. They are 0.28%-1.4% for Rc, 10-15 mm for DR, 1.97-3.5 for lrR, 40--50 for CSF. Based on pavement condition survey data collected on the test roads in Hebei Province, China, on the application of slurry seal at different timings, the pavement performance was established and the adequate timings for applying slurry seal was studied. Based on benefit-cost analysis, it is suggested that the fourth year is the optimal timing for applying slurry seal based on the condition in China. A framework is established to determine the adequate timings of applying other preventive maintenance methods.
文摘The purpose of this study is to explore whether it is worthwhile to launch a routine diabetic retinopathy (DR) screening for blindness pre-vention among Chinese type 2 diabetes from different perspective based on the popula-tion-based study in Kinmen, Taiwan. A total of 971 community dwelling adults previously di-agnosed with type 2 diabetes in 1991-1993 un-derwent DR screening in 1999-2002 by a panel of ophthalmologists using on-site indirect oph-thalmoscopy and 45-degree color fundus retinal photographs. The cost-benefit analysis is used to evaluate the DR screening. In terms of bene-fit-cost ratio, the different screening programs for DR could save New Taiwan Dollars (NTD) from 14.38 to 36.83 in discounted costs for each dollar incurred in different screening years from the societal viewpoint for Taiwan and save NTD from 0.81 to 1.80 in different screening years from health care payer’s perspective. The av-erage estimate of willingness-to-pay to translate into benefit yields NTD from 937.8 to 4,689 be- nefits per case due to DR screening in different screening years during 10-year follow-up. The net present value of the DR screening were NTD from -167,318 to -307,251.2 in different screening years. In conclusion, it is worthwhile to initial a routine DR screening of Chinese type 2 diabetes for blindness prevention from the societal per-spective but not from consumer decision based on the willingness-to-pay perspective.
基金Supported by National Natural Science Foundation of China(11601001)Scientific Research Innovation Fund of Anhui University of Finance & Economics(XSKY1957)
文摘Ecological and environmental issues have always been the focus of government work. The economic losses caused by air pollution,water pollution,noise pollution and solid waste pollution caused by land use development projects are estimated,and the total population economic losses are incorporated into project costing. Using the analytic hierarchy process,four benefit indicators and five cost indicators are selected for constructing a fuzzy comprehensive evaluation model to evaluate the cost-benefit of projects of different scales. The projects of different scales are ranked according to the level of comprehensive scores. The results show that large-scale projects are cost-effective and stable over the long term,and there are differences in the main sources of pollution-caused economic losses for projects of different scales. At last,reasonable policy suggestions are made to relevant planning and management personnel.
文摘In this in-depth exploration, I delve into the complex implications and costs of cybersecurity breaches. Venturing beyond just the immediate repercussions, the research unearths both the overt and concealed long-term consequences that businesses encounter. This study integrates findings from various research, including quantitative reports, drawing upon real-world incidents faced by both small and large enterprises. This investigation emphasizes the profound intangible costs, such as trade name devaluation and potential damage to brand reputation, which can persist long after the breach. By collating insights from industry experts and a myriad of research, the study provides a comprehensive perspective on the profound, multi-dimensional impacts of cybersecurity incidents. The overarching aim is to underscore the often-underestimated scope and depth of these breaches, emphasizing the entire timeline post-incident and the urgent need for fortified preventative and reactive measures in the digital domain.
基金This work was funded by the Israel National Coal Ash Board(INCAB)Grant#39477.The authors wish to express their deep gratitude to the late Mr.Omri Lulav,Head of the INCAB.
文摘A tool for calculating the economic and environmental impacts of the use of byproducts of industrial processes that can substitute for perishable resources was presented.This was exemplified by fly ash(the fine fraction of ash originating from coal burned to generate electricity and collected by filtering exhaust gases leaving the furnace),added to soil as a component of sewage sludge stabilized with fly ash and lime(NVS).Application to soil of NVS has potential agricultural and environmental advantages and disadvantages.The costs and benefits of such application were calculated using both a database and expert opinions.The calculations assumed a representative assemblage of soils and crops,with weights assigned to each crop type and soil characteristic.The annual weighted benefits(additional income for the farmer)and costs per hectare reached 324$/ha and 131$/ha respectively.Major potential benefits include:Chemical fertilizer replacement,159$/ha;Improvement to the soil’s physical properties,75$/ha;Supply of vital trace elements,33$/ha.Major potential costs were:Regulatory limitations on marketing of crops pending proof of absence of risk of heavy metals or radionuclides accumulation in these crops,(17$/ha and 36$/ha respectively);Application and incorporation cost,50$/ha.The presented estimates of the costs and benefits refer to the array of soils and conditions typical to Israel.It is possible to maximize potential benefits by applying fly ash only to the most suitable agricultural soils while improper use of fly ash will increase the costs incurred from its use.
文摘Owing to high costs and unnecessary inspections necessitated by the traditional inspection planning for ship structures, the risk-based inspection and repair planning should be investigated for the most cost-effective inspection. This paper aims to propose a cost-benefit assessment model of risk-based inspection and repair planning for ship structures subjected to corrosion deterioration. Then, the benefit-cost ratio is taken to be an index for the selection of the optimal inspection and repair strategy. The planning problem is formulated as an optimization problem where the benefit-cost ratio for the expected lifetime is maximized with a constraint on the minimum acceptalbe reliability index. To account for the effect of corrosion model uncertainty on the cost-benefit assessment, two corrosion models, namgly, Paik' s model and Guedes Soares' model, are adopted for analysis. A numerical example is presented to illustrate the proposed method. Sensitivity studies are also providet. The results indicate that the proposed method of risk-based cost-benefit analysis can effectively integrate the economy with reliability of the inspection and repair planning. A balance can be achieved between the risk cost and total expected inspection and repair costs with the proposed method, which is very. effective in selecting the optimal inspection and repair strategy. It is pointed out that the corrosion model uncertainty and parametric uncertaintg have a significant impact on the cost-benefit assessment of inspection and repair planning.
文摘Objective Phenylketonuria (PKU) and congenital hypothyroidism (CH) are common diseases thatare associated with mental retardation. In order to make the best use of health care resources to achieve themaximum social and economic benefits and to lay the foundation for the popularization of neonatal screening, acost- benefit analysis of neonatal screening program was undertaken. Methods Based on screening results,medical history and the data published by the national statistic departments. Results Our result shows that it islairly profitable to conduct neonatal screening in China: the cost - benejit ratio for PKU screenging is 1:3.7, andthe cost-benefit ratio for CH screening is 1:3.6. Conclusion This report therefore strongly suPPorts furtherpopularization of neonatal screening in China.
文摘On the basis of market demand survey of chestnut,this article carries out cost-benefit analysis of the chestnut production in Xingtai County,to understand the profitability and payback period of local chestnut production.It points out that chestnut production has a high rate of return on investment,and chestnut can be promoted on a large scale in Xingtai County.However,there are still some problems in the production and marketing of chestnut in Xingtai County,such as low level of technology,extensive management,low level of organization,market imperfections and weak brand consciousness.Based on these problems,corresponding recommendations are put forth.
基金Supported by Pig Industry Innovation Team Building Program of Modern Agricultural Industrial Technology System in Shandong Province(SDAIT-06-011-10)"Issues concerning Agriculture,Farmers and Countryside"Soft Science Base Project in Shandong Province
文摘According to the relevant statistical data in National Agricultural cost-benefit Data Compilation(2001- 2013),we use the modified entropy weight- TOPSIS model to research the cost-benefit status of scale pig breeding in Shandong Province from the perspective of comparing it with that of the entire country and 9 other main pig producing areas. The results show that compared with the national average,the cost-benefit ratio of small scale pig breeding in Shandong Province is lower,while the cost-benefit ratio of medium scale and large scale pig breeding is significantly improved; the cost-benefit ratio of small scale pig breeding in Shandong Province is basically the same as that in 9 other main pig producing areas,while the cost-benefit ratio of medium scale and large scale pig breeding is higher; the output value of main products and the purchase price of piglet are two major bottlenecks restricting the cost-benefit improvement of scale pig breeding in Shandong Province.
基金Supported by the Project of National Natural Science Foundation "3-stream Conjecture,Fulkerson-coverage and Related Issues"(11601001)
文摘With the rapid economic development of China,the environmental degradation brought by economic development cannot be ignored.In order to measure the cost of environmental degradation brought by land projects in the process of economic development and evaluate a land project,this paper establishes an ecological service evaluation model based on cost-benefit method to analyze the cost and benefit of land development projects from a new perspective,and explore effective strategies to alleviate environmental degradation.
基金The work was supported by the National Nature Science Foundation of China(71532009,71320107003,71271145)Core Projects in Tianjin Education Bureaus Social Science Program(2014ZD13)Tianjin Development Program for Innovation and Entrepreneurship.
文摘With the introduction of many derivatives into the capital market,including stock index futures,the trading strategies in financial markets have been gradually enriched.However,there is still no theoretical model that can determine whether these strategies are effective,what the risks are,and how costly the strategies are.We built an agent-based cross-market platform that includes five stocks and one stock index future,and constructed an evaluation system for stock index futures trading strategies.The evaluation system includes four dimensions:effectiveness,risk,occupation of capital,and impact cost.The results show that the informed strategy performs well in all aspects.The risk of the technical strategy is relatively higher than that of the other strategies.Moreover,occupation of capital and impact cost are both higher for the arbitrage strategy.Finally,the wealth of noise traders is almost lost.
文摘Motor vehicle inspection and maintenance (I/M) programs are designed to identify high-emitting vehicles and mitigate their impacts on air quality and climate. I/M programs have been traditionally ranked superior among various vehicle emission control measures by the results of cost-benefit analysis, based on the assumption that these programs will achieve the targeted emission reduction outcomes. However, the actual effects of I/M programs may be greatly uncertain and when this uncertainty is taken into account, these programs may become suboptimal. This study develops a new a cost-benefit analysis framework that links various program design consideration, such as program participation rate, identification rate and effective repair rate, to the public health benefits as well as costs of the programs. This framework helps decision makers to investigate minimum implementation requirements that at least ensure the benefits are greater than the costs of implementing the programs in order to improve the overall effectiveness of the I/M programs. To illustrate the applications of the framework, it was applied to a particulate matter oriented I/M program targeting all diesel-fueled vehicles in the city of Bangkok, Thailand, a large metropolitan area that has been suffering from severe ambient PM pollution mainly attributable to its wide use of diesel-fueled vehicles and motorcycles. It was found that the health benefits achieved from the program are sensitive to several key program design elements, including participation rate and problem vehicle identification rate, fraction of effective repairs and illegal operation rate. Other variables, such as the testing cut-points and vehicle population growth rate, only have modest effects on the overall emission reduction and consequent health benefits. Overall, the performance of multiple variables associated with I/M program design needs to be improved simultaneous in order to achieve the targeted benefits of the program.
文摘From the point of cost-benefit flow and with the Six Green Projects in China as the case and background, it is criticized that the current natural resource and environmental management and the policies in China have some problems unsolved since the model of cost-benefit flow is still centralized and mainly in an administrative way in spite of many efforts made theoretically and practically. It is suggested that a new model based on market-oriented economy from the point of cost-benefit flow with Six Green Projects Management and Policies System consist of complete natural reserve (NR). Management system included environmental nature reserves in addition to biodiversity nature reserve, paid using nature resources, an environmental conservation and construction industry and renewable resource production incentive system that turn the direct administration and operation to management and services. The detail figure of the new model of cost-benefit flow is provided and the main points related are discussed in this paper.
文摘The objective was to assess the impact on health due to the exposure to air pollution derived from the renewal of the urban bus fleet in S?o Paulo. The study analyzed the substitution of the bus fleet through the variation of the concentration of atmospheric pollutants such as PM10 in the municipality of S?o Paulo and its associated health’s benefits values compared to the investments performed in the bus fleet renewal. PM10 average annual reduction due to the bus improvement system resulted on 22.3%. A cost-benefit evaluation considered the renewal investments’ costs compared to the obtained valued health benefits and it resulted in 4.31. Although the result may suggest a not viable investment, it must be observed that air pollution reduction favors health impacts and that this relation could be improved if additional investments on sustainable transportation increase.
基金National Natural Science Foundation of China (41971215, 41701193)Youth Innovation Promotion Association, Chinese Academy of Sciences (2022317)。
文摘Within the inventory era, urban shrinkage characterized by economic decline and space decay has been widely witnessed in China. The modes and trajectories of urban redevelopment have thus become areas of major concern for both policymakers and scholars. Taking the multi-actor participation nature of redevelopment, this paper stemming from the game-theoretical approach demonstrates in empirical terms on two major fronts. First, the redevelopment of industrial land without the transfer of land use right is shown to be deadlocked by the incapacitation of the original land-user and unlocked with the participation of the new developer. Second, the preference of the original land-user to maximize its interests by operating by itself rather than continue to cooperate with the new developer is observed in the post-redevelopment stage. Therein, the entrepreneurial local government acts only as a “mediator” between the two market entities and tends not to directly intervene in their cooperation. Thus that, it is the reasonable distribution of potential benefits or the pricing of different rights in the land property right bundle rather than their definition that matters more for land redevelopment. Because the delineation of land property rights has never been a problem in a mature land market, particularly for stock industrial land.