Benefit-cost analysis of raising Pinus wallichiana seedlings in different capacities/sizes of root trainers in the nursery

Modern nursery methods of seedling production in different sized root trainers, were compared by raising seedlings of Pinus wallichiana involving costs incurred and benefits received. In order to provide a common basis for the comparisons, the study involved the raising of 1000 seedlings annually on a continuous basis for seven years. A relative economic analysis of raising P. wallichiana seedlings in 300, 150 and 100 cm^3 root trainers was carried out and we estimated that the root trainers of 300 cm^3 capacity recorded the highest total input cost of Rs. 35571 and Rs. 40018 for 1000 seedlings produced annually at discount rates of 12% and 6%. Seedlings raised in 100 cm^3 root trainers recorded the lowest total input cost of Rs. 23390 and Rs. 27737 per 1000 seedlings annually at discount rates of 12% and 6%. Hence, returns per rupee invested in raising seedlings in the 100 cm^3 root trainers accounted for the maximum benefit-cost ratio （i.e., 1.56 and 1.61） at discount rates of 12% and 6%. Thus seedlings raised in 100 cm^3 and 150 cm^3 root trainers were found to be most cost effective when compared with seedlings grown in 300 cm^3 root trainers. The results can be attributed to the larger number of cells per tray （higher growth density） in the 100 and 150 cm^3 root trainers, compared to the number of seedlings in the 300 cm^3 root trainers.

基于含权k-壳分解的分组教学虚拟网络映射算法

提出一种两阶段的基于含权k-壳分解的分组教学虚拟网络映射算法。该算法根据含权k-壳分解法对底层网络进行预处理,然后沿着节点间的最短路径映射链路,并结合分组教学优化模型的分组、教学、自学与互学的优化策略,实现节点和链路的协调映射,从而进一步提高解的质量。仿真结果表明,所提算法作为一种多目标的虚拟网络映射算法,能够有效减少链路开启量,提升虚拟网络请求接受率及长期收益成本比。

Economic Viability of Smallholder Agroforestry and Beekeeping Projects in Uluguru Mountains, Tanzania: A Cost Benefit Analysis

Agroforestry and beekeeping are widely promoted as prospective Nature- Based Income Generating Activities (NIGAs) to improve livelihoods while at the same time enhancing biodiversity conservation in degrading agro-ecologies. These activities can diversify and increase famers’ incomes and support instinctive biota and fauna resilience. However, evidence to showcase and compare their long-term benefits is scant. We use the case of Uluguru Mountains in Tanzania to evaluate and compare viability of agroforestry and beekeeping projects using the Cost Benefit Analysis (CBA) approach. The results of analysis yielded positive NPVs for both agroforestry and beekeeping projects at discount rates not higher than 8.2% and 8.5% respectively. Overall, the comparison of economic viability between agroforestry and beekeeping projects revealed that the former was relatively more profitable than the later in terms of both the NPV and Benefit Cost Ratio (BCR) criteria. However, the Internal Rate of Return (IRR) for beekeeping was slightly higher than that of agroforestry. Yet, we underscore the fact that these two projects can jointly be implemented to enhance livelihoods of farmers and support biodiversity conservation in the study area and other parts with similar agro-ecologies in developing countries. However, farmers in these agro-ecologies need to be supported by governments and non-government development partners in terms of training and inspiration to shift from orthodox farming to sustainable NIGAs.

Operation Benefit of Fruit Dealers in Shizishan Street Farm market

This paper mainly discussed the operation benefits of fruit dealers in farm market. Taking fruit dealers in Shizishan Street Farm market in Wuhan City as the research object,this paper introduced current operation situation of fruit dealers and made a descriptive statistical analysis on characteristics of operators,operation situation,and cognitive status. Besides,it introduced the concept of net cost-benefit ratio to reflect the operation benefits. From further analysis on the operation benefits of fruit dealers,it found that there is little difference in the costbenefit ratio between dealers in the farm market. The average net cost-benefit ratio was 11. 94%. Specifically,if the total cost is 100 yuan,the dealer can obtain 12 yuan net profit. In order to find out how cost factors affect the operation benefits,it established a regression model for cost factors and net cost-benefit ratio. According to the survey results,when the wholesale cost increases 10000 yuan,the cost-benefit ratio will increase by 1. 454 percentage points,thus increasing the wholesale investment is helpful for increasing the net cost-benefit ratio; when the loss cost increases 10000 yuan,the cost-benefit ratio will increase by 7. 501 percentage points,thus the dealers can increase the operation benefits through controlling the loss cost and reducing the operation cost. Finally,it came up policy recommendations from the perspective of government and operators.

Dry Season Feeding Technologies: Assessing the Nutritional and Economic Benefits of Feeding Hay and Silage to Dairy Cattle in South-Western Uganda

South-western Uganda annually experiences prolonged drought that results in dramatic drop in milk production of dairy cattle. This study was conducted to assess the nutritional value and economic benefits of feeding silage and hay to dairy cattle in the sub-region. The cross-sectional study covered seven districts with 105 farmers interviewed during the wet and 45 others in the dry season. Up to 88 soil samples were collected and analyzed for soil texture, soil pH, organic matter and total Nitrogen, Phosphorus, Potassium, Calcium, Sodium and Magnesium. Likewise, 148 forage (105 fresh, 25 silage and 18 hay) tissues from 21 pasture species were collected and analyzed for nutritional values. Using a questionnaire, data on production costs and milk revenues were collected for cost-benefit analysis. Results showed that silage of Napier grass treated with molasses (10.2 MJ/kg) and hay of naturally established pastures (10.6 MJ/kg) had the highest metabolisable energy (ME) values, while the lowest (8.30 MJ/kg) was for star grass. Hay of star grass presented the highest level of crude protein (21.4%) with maize (corn) showing the lowest (9.38%). Digestibility of hay of naturally established mixed pastures was the highest (64.4%), followed by that of silage of Napier grass treated with molasses (62.0%), while star grass hay had the lowest (52.6%). With exception of silage made from maize, all the other six forms of silage had a good crude protein (CP) content. Regardless of the good CP content (≥9.9%), all silage untreated with additives was poor in quality since its ME was less than 9.9 MJ ME/kg and ration digestibility less than 67%. Nonetheless, feeding of silage and hay increased milk yield and farm productivity with a benefit-cost ratio of 5.5 and 2.7 for silage and hay respectively.

新业态从业人员参加养老保险的成本收益与收入再分配效应——基于共同富裕视角

基于个人和社会角度,意在探讨哪种参保选择能同时满足个人的“成本收益”效应最大化和社会的“收入再分配”效应最大化,以达到推进共同富裕的效果。采用2018年中国劳动力动态调查微观数据(CLDS),构建精算模型研究发现:新业态从业人员基本养老保险全覆盖可使养老金成本收益比增加,使养老金基尼系数减小;养老金成本收益比随城职保参保率提高而增大,基尼系数随城职保参保率提高而减小;提升城职保参保率与增加缴费指数相结合的政策可以发挥更大的成本收益效应和收入再分配效应。为实现共同富裕的伟大目标,应加快推进新业态从业人员社会保险全覆盖,鼓励新业态从业人员参加城职保。

α-2b干扰素治疗慢性丙型肝炎的经济学评价

目的:对上海、北京和石家庄三城市应用α-2b干扰素治疗慢性丙型肝炎做经济学评价.方法:根据对三城市的部分慢性丙肝、代偿性肝硬化、失代偿性肝硬化病人调查所得的门诊费用、住院费用.并根据慢性丙型肝炎的自然史和α-2b干扰素的治疗效果,预测并比较α-2b干扰素治疗组和常规治疗组的慢性丙肝病人在30a内的有关费用和预后,并进行成本-效益和成本-效果分析.结果:治疗后30a内,α-2b干扰素治疗组比常规治疗组增加852个存活人年和1487个生命质量调整年.α-2b干扰素治疗组比常规治疗组节省医疗费用29459371元,效益-成本比值为1.32.α-2b干扰素治疗组比常规治疗组每增加一个生命年所节省的费用为8321元,每增加一个生命质量调整年所节省的费用为4768元.结论:应用α-2b干扰素治疗慢性丙型肝炎可取得较好的临床和经济学结果.

基于性能和寿命周期成本的路面预防性养护措施选择

为践行《广东省“十四五”干线公路养护管理提升行动方案》,在归纳总结近年来高速公路沥青路面预防性养护成功经验的基础上,结合某高速公路沥青路面实际技术状况检测结果,探索以养护措施性能和寿命周期费用为指标的最佳预防性养护方案的确定方法。研究结果有益于完善全寿命周期效益最优的公路养护科学决策体系,规范现有高速公路预防性养护措施选择程序,为高速公路预防性养护方案和施工图设计提供科学依据。

论净现值、收益-费用比率以及内部收益率的关系

净现值、收益-费用比率和内部收益率是使用最广泛的投资决策标准。但是,同时采用这些标准对多方案选优有时会得到不同的结论。本文首先从经济含义上讨论了它们的区别与联系,然后,从数理逻辑上论证了它们之间的关系,并且分析了其结论一致的条件。该结论可作为投资项目评价的新标准。

基于遗传算法的路网级桥梁养护与安全分析

随着交通网络的发展和桥梁结构的老化,养护工作变得更加重要,而传统的养护决策存在工作繁琐、效率低下的问题。因此,研究提出建立桥梁安全风险分析体系,并借助带精英策略的非支配排序遗传算法进行路网级桥梁养护决策。试验结果显示,研究方法在150次迭代后完成收敛,共得出100种有关竹埠港湘江大桥养护的决策。选择其中具有代表性的决策进行分析,考虑次要结构时最优决策经费为252万元,效益费用比达到0.99,不考虑次要结构的最优决策经费为129万元,效益费用比为1.60。且养护后撞击力降低了44.91%,吸收撞击能量提高了38.13%。研究为路网级桥梁的养护与安全风险分析提供了系统、科学的方法,对于提高桥梁养护效益、减少养护成本,以及确保桥梁结构安全具有积极意义。

政府职能转变的成本-收益分析:基于地区间的比较

经济转轨期间，政府改革目的就是要对政府职能重新界定，让政府也成为市场经济中的“理性人”，为此，就需要对政府职能转变进行成本-收益核算。利用1994-2003年间的数据，本文采用成本-收益比率法对30个省市政府职能转变效率进行了评估，结果表明东部地区政府职能转变效率最高。中西部次之。

甘肃省新生儿听力筛查与救助项目收益-成本分析

目的利用收益一成本比（benefit-cost ratio，BCR）评估甘肃省畸变产物耳声发射（DPOAE）联合自动听性脑干反应（AABR）进行新生儿听力筛查以及听力医疗救助的经济效益，为听力学家、管理人员以及参与新生儿普遍听力筛查的其他人员提供参考依据。方法出生后48～72小时应用DPOAE及AABR进行初次听力筛查，任意一项未通过者干出生后42天进行DPOAE联合AABR复筛，未通过者于3月龄时进行听力学诊断性检查，从而获得新生儿先天性听力损失的发病率，结合甘肃省卫生部门财政投入估算费用及货币化收益来计算BCR。结果①每例新生儿筛查成本为49元；②每例听力障碍患儿筛查成本为25466元；③每例中度以上听力障碍患儿筛查成本为48063元；④通过成本和效益估算表明BCR=8．11。结论甘肃省新生儿听力筛查与救助项目获得的收益超过成本，该项目符合收益一成本的原则。

贵州农村家庭炉灶及燃料改良成本-健康效益研究

固体燃料燃烧引起的室内空气污染易导致人体健康损害。文章采用WHO推荐的基于燃料的成本效益计算方法,对贵州省使用固体燃料(柴薪和煤)的农村农户炉灶及燃料改良干预的成本-健康效益进行研究。结果表明,在采用清洁能源(沼气)替代、无烟囱炉灶改造、部分清洁能源和部分炉灶改造结合的3种干预情景下,均能取得较高的健康效益,能减少室内空气污染所致的儿童急性下呼吸道感染(ALRI)、成人慢性阻塞性肺炎(COPD)、成人肺癌的发病率,测算出这3种干预场景减少的早死亡病例数分别可达9 419、2 617、5 509例,健康效益/成本比BCR分别为3.6、2.3、3.0,在贵州农村地区实行炉灶干预措施能取得较好的健康效益。

住宅建筑节能产品选用的成本-能效分析

住宅建筑节能作为建筑节能的重头戏,其意义和地位举足轻重。如何有效地选用同时满足节能要求和节省成本的产品已成为备受关注的问题。以典型住宅单元作为载体,分别对目前市场上常见的16种节能产品进行了成本-能效分析,并根据分析结果对这些产品的能效成本比进行了排名。这些产品的能效分析借助REM/Rate软件获得,成本价格结合全国定额水平和市场调查获得。结合开发商和业主所在地区的节能产品价格,本研究所提供的分析方法可用于优化节能产品的选用。

Agro-Economic Implications of Combined Application of Organic and Mineral Fertilizers on Maize

Continuous cultivation without adequate fertilizer application is responsible for plant nutrient depletion and yield decline of major food crops in sub-Saharan Africa. Field experiments were conducted on umbric Cambisol in Babungo and ustic Oxisol in Bansoa in the Western Highlands of Cameroon over two years to evaluate the effects of combined application of leaf biomass of agroforestry species and mineral fertilizers with their economic returns on maize yield performance. Ten treatments encompassing sole mineral fertilizer, sole leaf biomass of Calliandra, Leucaena, Acacia and Cassia, leaf biomasses combined with mineral fertilizer and absolute control were laid in a randomized complete block design and replicated three times. Data collected on maize grain yield was subjected to analysis of variance using XLSTAT version 2014 statistical software. In addition, an economic analysis was performed to evaluate the profitability of the different treatment combinations. The results showed significant differences (P ≤ 0.05) amongst the different treatments on maize yield on both soil types. The highest maize yields which stood at 5.93 t/ha and 6.01 t/ha were recorded in plots treated with Acacia and Cassia plus half recommended mineral fertilizer on umbric Cambisol and ustic Oxisol respectively. Economic analyses showed that Acacia and Cassia plus half recommended mineral fertilizer gave the highest net benefit and return to labor of 286500 FCFA and 5.1 on umbric Cambisol and 296051 FCFA and 5.3 on ustic Oxisol respectively. On both soils, all the treatments except Calliandra with half recommended mineral fertilizers were economically profitable with benefit to cost ratios that ranged from 2.02 to 2.92. Combined application of agroforestry tree species leaf biomass and mineral fertilizers is an appropriate technology to enhance maize grain yield and is economically profitable except Calliandra with half recommended mineral fertilizers and is therefore recommended for degraded Calliandra and Oxisols in the Western Highlands of Cameroon.

改进MPGA优化基于效-费比的TMD装置

经过几十年的发展,关于质量调谐阻尼器(TMD)性能的研究已日趋成熟,而只有少数文献从效-费比方面对TMD减震控制系统进行经济性的研究,这也是制约TMD减震控制技术发展的原因之一。研究了改进多种群遗传算法在考虑SSI效应的TMD控制结构中效-费比优化问题。首先,分析TMD装置系统的全寿命周期费用LCC(LifeCycleCost)的构成,建立TMD各组成部分非线性成本函数,然后,将成本函数代入改进多种群遗传算法,在满足所设置的结构减震百分率基础上寻求成本最小化,即在满足业主具体的抗震性能要求的前提下,以效-费比为优化性能指标,求出减振控制系统的最优参数,以最低的费用,达到最好的减震效果。

2001—2020年我国甜菜成本收益动态演变与原因探究

本文基于《全国农产品成本收益资料汇编》的单位面积成本和收益数据,采用趋势分析法和比较分析法探究了2001—2020年我国和新疆、内蒙古、黑龙江三个主产区甜菜总成本和收益的变化规律,进一步探究了甜菜成本收益动态演变的驱动因素。结果表明:(1)2001—2020年我国甜菜总成本逐步提高,2018年达到高位后有所回落,20年年均增长率为7.45%,从成本增长的绝对数额来看,物质与服务费用和人工成本居前两位;从年均增速来看,地租和人工成本增速居前两位。(2)2020年物质与服务费用、劳动力成本、土地成本分别占甜菜总成本的45.33%、35.76%和18.91%。(3)从三个主产区20年成本均值看,新疆总成本最高、内蒙古其次、黑龙江最低;单产由高到低依次为新疆、内蒙古、黑龙江;从甜菜成本内部结构来看,新疆物质与服务费用占比最高,内蒙古人工成本占比最高,黑龙江土地成本占比最高。(4)三大主产区总成本总体呈上升趋势,新疆、内蒙古增量明显高于黑龙江;而黑龙江增速最快、内蒙古其次。(5)我国甜菜成本利润率呈先增、后降、再震荡回升态势,经历了三个周期和一个未完成周期,2011年达到最高,2016年处于最低,近20年成本利润率均值为26.51%,2020年成本利润率约为9.53%。(6)内蒙古化肥投入数量呈现先增(2010—2017年)后降(2018—2020年)态势,化肥农药“零增长”政策在内蒙古初现效果。(7)成本收益变动的主要影响因素包括劳动力成本和物质与服务费用快速增加,使得甜菜比较效益不高,异常气候频发、重迎茬和除草剂残留问题影响单产和甜菜收益,副产品综合利用不高,甜菜种子价格偏高且主要依靠进口。这些研究结论为推动我国甜菜产业高质量发展提供现实依据。

Cassava Groundnut Intercropping: A Sustainable Land Management Practice for Increasing Crop Productivity and Organic Carbon Stock on Smallholder Farms

Cassava-groundnut intercropping is not a common practice among smallholder farmers in Sierra Leone even though both crops are well suited for intercropping. On-farm trials were conducted in three locations (Bai Largor, Bassah, and Njala Kanima) in the Moyamba district during the 2021 cropping season to investigate the efficacy of cassava-groundnut intercropping for increasing crop productivity and soil organic carbon stock on smallholder farms in the Moyamba district, Southern Sierra Leone. The experimental design was a randomized complete block design in three replications with treatments of sole groundnut, sole cassava and cassava-groundnut intercropping. Data on the yield and yield components of cassava and groundnut were analysed using the PROC MIXED procedure of SAS 9.4 and means were compared using the standard error of difference (SED). The above-ground biomass, number of roots per plant, and fresh root yield of cassava were not significantly (p > 0.05) affected by the cassava-based cropping system. Averaged across locations, intercropping cassava with groundnut decreased the above-ground biomass, the number of roots per plant, and fresh root yield of cassava by 17%, 11%, and 17%, respectively. The above-ground biomass, number of pods per plant and fresh pod yield of groundnut were significantly (p 1), the highest net revenue and benefit-cost ratio. The benefit-cost ratio was also favourable for the sole cassava (BCR > 1) but not favourable for the sole groundnut (BCR < 1). Averaged across locations, intercropping cassava with groundnut increased the benefit-cost ratio by 121% and 13% when compared to the sole groundnut and sole cassava. In the event of a 40% yield loss for the cassava and groundnut, the benefit-cost ratio was favourable (1.12) only for the cassava groundnut intercropping system. The net soil organic carbon stock was favourable only for the cassava-groundnut intercrop. Averaged across locations, the net soil organic carbon for the cassava-groundnut intercropping increased by 3.4% when compared to the baseline within one cropping cycle of the cassava (12 months). The results confirm that cassava-groundnut intercropping is a sustainable land management practice that could enhance crop productivity and soil organic carbon stock on smallholder farms.

分布式光伏发电并网的成本/效益分析

在全球节能减排、能源安全的巨大挑战下,发展可再生能源成为推动后危机时代经济转型、发展低碳经济的重要手段。而国家发改委发改价格[2013]1638号文的出台,使众多光伏企业看到了国内市场开始启动的迹象。文章分析了目前国内光伏发电的主要运营模式,提出分布式光伏发电并网的经济性评价流程,建立了不同运营模式下光伏发电的全寿命周期成本/效益计算方法与模型,并分析了不同运营模式下分布式光伏发电的两种并网设计方案。最后综合考虑运营管理模式、发改价格[2013]1638号文规定的补贴方式,对某实际案例进行成本效益分析。结果表明,对于分布式光伏发电项目,电价补贴方式的成本效益优于建设补贴方式,因此发改价格[2013]1638号文的出台,必将激励国内光伏市场的启动。研究成果有助于解决光伏发电并网成本效益的问题,为光伏发电并网及运营管理模式等相关配套政策的制定奠定理论基础。