Maximum Net Benefit Indicator and Its Applications

Receiver operating characteristics(ROC)curve and the area under the curve(AUC)value are often used to illustrate the diagnostic ability of binary classifiers.However,both ROC and AUC focus on high accuracy in theory,which may not be effective for practical applications.In addition,it is difficult to judge which one is better when the ROC curves are intersect and the AUC values are equal.Decision curve analysis(DCA)methods improve ROC by incorporating accuracy and consequences.However,similar to ROC,DCA requires a quantitative indicator to objectively determine which one is better when DCA curves intersect.A DCA-based statistical indicator named maximum net benefit(MNB)is constructed for evaluating clinical treatment regimens rather than just accuracy as in ROC and AUC.As a simple and effective statistical indicator,the construction process of MNB is given theoretically.Moreover,the MNB can still provide effective identification when the AUC values are equal,which is proved by theory.Furthermore,the feasibility and effectiveness of the proposed MNB are verified by gene selection and classifier performance comparison on actual data.

Measuring the Social Net Benefits of COVID-19 Restrictions: The Case of Reduced Vehicle Use in a Pollution-Prone Region of Utah

A number of natural experiments have recently found that COVID-19 restrictions imposed in nations worldwide are correlated with short-term reductions—in some cases dramatic reductions—in mobile-source air pollutants. Noticeably absent from these studies are estimates of the social net benefits associated with the changes in human behavior underlying the pandemic-induced effects. Using readily available data provided by the state of Utah and the U.S. Environmental Protection Agency’s Co-Benefits Risk Assessment Health Impacts Screening and Mapping Tool (COBRA), we find that daily social net benefit was positive during a pandemic-induced shutdown from March to April, 2020 in Utah’s Wasatch Front region solely when COBRA’s “high” health benefit estimate from combined reductions in PM2.5 and NOx concentrations are weighed against the region’s “low” vehicle-trip cost estimate. All other scenarios correspond with negative net benefit estimates, i.e., when high and low benefit estimates of reductions solely in PM2.5 concentrations as well as for combined reductions in PM2.5 and NOx concentrations are weighed against the region’s high vehicle-trip cost estimate. Generally speaking, social net benefits are higher for two of the Wasatch Front’s four counties.

Hypothesis testing by simulation of a medical study model using the expected net benefits criteria

Introduction: This work investigates whether to conduct a medical study from the point of view of the expected net benefit taking into account statistical power, time and cost. The hypothesis of this paper is that the expected net benefit is equal to zero. Methods: Information were obtained from a pilot medical study that investigates the effects of two diagnostic modalities, magnetic resonance imaging (MRI) and computerized axial tomography scanner (CT), on patients with acute stroke. Statistical procedure was applied for planning and contrasting equivalence, non-inferiority and inequality hypotheses of the study for the effectiveness, health benefits and costs. A statistical simulation model was applied to test the hypothesis that conducting the study would or not result in overall net benefits. If the null hypothesis not rejected, no benefits would occurred and therefore the two arms-patterns of diagnostic and treatment are of equal net benefits. If the null hypothesis is rejected, net benefits would occur if patients are diagnosed with the more favourable diagnostic modality. Results: For any hypothesis design, the expected net benefits are in the range of 366 to 1796 per patient at 80% of statistical power if conducting the study. The power depends on the monetary value available for a unit of health improvement. Conclusion: The statistical simulations suggest that diagnosing patients with CT will provide more favourable health outcomes showing statistically significant expected net benefits in comparison with MRI.

基于GLIM评分的帕金森病患者营养不良风险预测模型构建

目的 研究预测帕金森病患者营养不良风险的模型,为早期营养干预提供依据。方法 选择郑州大学第二附属医院神经内科2020-01—2022-12收治的229例帕金森病患者为研究对象。收集患者的临床资料并使用全球(营养)领导人发起的营养不良评定(诊断)标准对患者进行营养风险筛查。通过机器学学习的方法构建帕金森病患者营养不良筛查模型。结果 营养不良组患者Hoehn-Yahr分级3~4级患者数量较营养正常组患者数量高,营养不良组患者病程较营养正常组患者时间长,差异均有统计学意义(均P<0.05)。Lasso回归模型及多因素Logistic回归分析构建的帕金森病患者营养不良风险预测模型显示:Hoehn-Yahr分级、病程、体重指数、C反应蛋白和白蛋白是帕金森病患者合并营养不良的危险因素。该列线图模型的C指数为0.837(95%CI:0.787~0.887),受试者工作特征曲线下面积为0.837,显示较好的预测价值。决策曲线分析所示当概率值为2%~79.0%时,使用此模型,患者临床净获益率最高。结论 该列线图模型为有效筛查帕金森病患者营养不良风险提供了一种实用方法,为尽早进行营养干预提供了依据。

条带垄覆对西南黄壤坡耕地径流和高粱水分利用的影响

针对西南区坡耕地季节性干旱突出、降水径流损失大、高粱低产低效益等问题。2020—2021年,在黔西南山区以前茬种植春玉米的7°黄壤缓坡耕地为研究对象,研究了横坡种植模式(作物行向与坡向垂直)下传统露地平作(CK)、条带垄覆地膜(RFM)和条带垄覆玉米整秆(RSM)3种不同处理对径流、以及高粱耗水特性、水分利用效率、产量和纯收效益的影响。结果表明,与CK相比,在横坡垄作模式下,RFM和RSM处理高粱生育期内的降雨径流深度分别平均显著下降27.3%和42.1%,纳水系数分别平均增加9.5和14.6个百分点。2个条带垄覆横坡种植较CK显著增加高粱生育期的耗水量,其中拔节至抽穗阶段、灌浆至成熟阶段耗水量与产量分别呈显著(r=0.51^(*))和极显著(r=0.81^(**))正相关。与CK相比,RFM、RSM显著增加高粱成熟期生物量、穗粒数和千粒重,籽粒产量分别平均显著增加8.5%和6.2%,但水分利用效率分别平均显著下降12.6%和21.4%。主要原因是,条带垄覆可显著增加高粱全生育期0~100 cm土壤贮水量,提高拔节至抽穗、灌浆至成熟阶段的耗水量,促进了高粱植株的生长发育和产量形成,且高粱秸秆产量的增幅(21.4%)显著高于籽粒产量增幅(7.3%),秸秆产量的大幅增加虽然降低了水分利用效率,但秸秆产量的增加是籽粒增产的重要保障。RSM处理的纯收益和产投比分别平均较CK增加2962.9元hm^(-2)和2.3%,而RFM处理由于增加了劳动强度、机械和地膜投入,导致纯收益和产投比分别平均较CK下降1502.6元hm^(-2)和32.6%。因此,条带垄覆玉米整秆横坡种植在显著提高降水有效性的同时,可实现产量和纯收益双增的目的,是西南黄壤旱坡耕地高粱增产增收的可行模式。

Benefit Analysis of Chemical Fertilizer Input for Staple Grain Production Based on Threshold Panel Data Model

Based on the threshold panel data model,this paper analyzed the nonlinear relationship between chemical fertilizer input and grain output. At the provincial level,from the perspective of average and marginal net benefits,it compared the effects of chemical fertilizer input on farmers' income. It reached the conclusion that the chemical fertilizer input efficiency has deviated from the optimal level. Thus,only by increasing the marginal productivity of chemical fertilizers,may it be able to increase farmers' income.

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.

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.

中国化石能源开采业净能源与环境经济综合评价

本文将中国化石能源开采业分为煤炭开采业和油气开采业,关注净能源生产、环境污染和经济效益3个方面,构建评价指标体系,对2005~2019年中国化石能源开采业及其子行业进行综合评价。结果显示:(1)2013年后,化石能源开采业的技术水平不断提升,2016年后其净能源产量保持递增;(2)2013年后,化石能源开采业的污染物治理效果逐渐变好;(3)2005~2019年间,化石能源开采业的资本存量波动性上涨;(4)2005~2019年间,油气开采业的综合评价结果始终优于煤炭开采业。2016年后,化石能源开采业及其子行业的综合评价结果保持上升,我国化石能源开采业及其子行业正处于良性的发展之中。

镉污染农田替代种植模式及经济效益研究

面向农田镉(Cd)污染背景下的农产品安全问题,探讨不同作物Cd累积规律及不同种植模式经济效益,为实现Cd污染农田安全生产提供科学依据。以Cd污染农田作为试验点,第一年选择14种作物开展了替代作物筛选试验,系统分析了不同作物的Cd累积特征,第二年选取达标率较好的替代作物设置了6种替代种植模式,深入探讨各替代模式的经济效益。结果表明,①研究区域小麦、水稻超标严重,传统稻麦轮作模式具有较高的生产风险;②从作物达标率来看,油菜、高粱、青菜、萝卜、胡豆、毛豆、薏仁、车前草、决明子适合作为替代作物;黄豆、花生、生姜、菊花、薄荷不适合作为替代作物;③车前草-毛豆轮作净利润、现金收益、成本利润率分别较传统稻麦轮作提升124%,123%,5.58%,优先推荐作为当地的替代种植模式。

降雨历时动态变化对临时苫盖措施坡面减流减沙效益的影响

工程堆积体具有独特的物质组成,其土壤抗侵蚀能力差,受暴雨冲刷极易导致水土流失,密目网苫盖作为一种重要的临时措施,定量揭示密目网苫盖的蓄水保土机理具有重要意义。为分析降雨历时动态变化对工程堆积体密目网苫盖减流减沙效益的影响,试验设计60,90,120 mm/h 3个降雨强度,对5°,15°,25°,35°共4个坡度的堆积体坡面在裸地和密目网苫盖处理下进行人工模拟降雨试验。结果表明:60 mm/h降雨强度时,密目网苫盖处理在15°~35°对坡面产流历时抑制作用显著(p<0.05),当大于60 mm/h时,在15°~25°可显著延长坡面产流历时(p<0.05);不同坡度下60 mm/h与90,120 mm/h降雨强度减沙效益差异显著(p<0.05),密目网苫盖处理减流减沙效益随降雨历时延长而减小,均在90 mm/h降雨强度达阈值;幂函数可很好地描述减流减沙效益随降雨历时的变化关系,效益衰减系数(b)随降雨强度增大陡增;密目网苫盖处理减流减沙效益随降雨历时变化可分为高效阶段、递减阶段和稳定阶段,最佳减流效益历时总体小于30 min,最佳减沙效益历时在20 min附近。综上所述,考虑生产建设项目水土保持工作的开展,当生产建设项目施工区以短历时(<30 min)、强降雨(<90 mm/h)为主要降雨类型时建议采用临时苫盖措施,可有效减少施工区水土流失。研究成果可为生产建设项目水土保持监管提供参考。

缓释肥与尿素组合基施对水稻生长及产量的影响

为达到环保及降低施肥次数的目的,本试验设计了3个基施缓释肥与尿素处理(3个氮素水平:N_(1),纯氮300.0 kg/hm^(2);N_(3),纯氮345.0 kg/hm^(2);N_(4),纯氮390.0 kg/hm^(2)),以常规施肥(N_(2),纯氮337.5 kg/hm^(2))作为对照,探究不同氮素水平的缓释肥与尿素基施对水稻生长与产量的影响。结果显示,在水稻分蘖后期,N_(2)(常规施肥)处理下水稻的分蘖能力达到最大,其次是N_(3)处理,水稻高峰苗也是在常规施肥下达到最高,高峰苗的总体变化趋势为N_(2)>N_(1)>N_(3)>N_(4)。水稻的株高随施氮水平的增加呈逐渐增加的趋势,且N_(2)—N_(3)处理可使水稻株高控制在合适的范围。从产量结构看,有效穗数和结实率均在N_(2)处理下达到最高,而千粒质量和实粒数均在N_(3)处理下达到最高。水稻产量高低排名为N_(3)>N_(2)>N_(1)>N_(4),主要在于千粒质量和实粒数的提高导致增产。考虑到经济效益,虽在N_(3)(纯氮345.0 kg/hm^(2))处理下由于缓释肥成本高导致水稻净效益低于常规对照,但从增产、施肥次数减少以及环保等角度出发,推荐水稻缓释肥与尿素基施纯氮用量按照N_(3)(纯氮345.0 kg/hm^(2))处理来进行。

基于案例的光伏建筑一体化系统全生命周期经济性分析

本文对建筑一体化光伏(BIPV)系统的经济分析进行全面研究和评估。通过考虑BIPV系统参数、经济因素以及社会和环境价值,研究BIPV系统在经济可行性和环境效益方面的潜力。结果表明,在净现值计算中考虑BIPV系统的社会和环境效益可以显著提高BIPV系统的经济可行性,将投资回收期从12年缩短到5年,为BIPV系统的经济分析提供有益见解。文章的计算结果期望为BIPV系统在可持续能源领域的推广和应用提供了基础。

源-荷应用场景下储热式电锅炉投资经济性分析

储热式电锅炉是一种电-热转换设备,可应用在电力系统的源、荷两侧,提升系统灵活性。为分析储热式电锅炉投资经济性,首先,基于储热式电锅炉在源-荷场景下运行模式的差异,构建不同场景下储热式电锅炉运行约束模型,分析不同模式下投资主体经济效益和社会综合效益构成;其次,基于时序生产模拟,以年度经济效益最大为目标,建立储热式电锅炉投资主体经济效益优化模型;最后,基于净现值法分析评估储热式电采暖投资主体的投资经济性,并以“三北”地区某省级电网开展实例分析,依据东北电力辅助服务市场运营规则测算,结果表明:不同应用模式均具有明显社会综合效益,热电厂投资模式的盈利能力最强,风电场投资模式和荷侧独立主体投资模式经济上不可持续,需要调整相应的市场运营策略。

净效益最大的平抑风电功率波动的混合储能容量配置方法

通过分析不同功率分配方法对储能容量配置的影响,提出了一种利用滑动平均和经验模态分解(EMD)获得储能参考功率的混合储能(HESS)功率和容量配置方法,并基于全寿命周期成本(LCC),考虑减少风电场旋转备用和缓建并网通道容量效益,以净效益最高为目标实时平抑风电功率波动。该方法首先利用滑动平均法得到HESS参考功率,采用EMD将其分解成一系列本征模态函数(IMF)。根据功率型和能量型储能的特性,以瞬时频率-时间曲线混叠最少为原则选择分界频率,将分解后的子分量重构成高、低频信号,分别作为功率型储能和能量型储能的参考功率。然后,考虑储能系统的充放电效率和荷电状态(SOC),配置不同储能组合方案下各储能的功率和容量,并与其他功率分配方法下的配置结果进行对比分析。最后,构建HESS的成本-效益模型,比较不同方案的净效益,得出经济最优的配置方案。

水肥耦合对棉花产量、收益及水分利用效率的效应

研究滴灌施肥条件下水肥耦合对棉花籽棉产量、水分利用效率和净收益的影响,并运用多元二次回归与归一化及3种不同目标值组合方式相结合的方法,探索满足多目标综合效益最大化的滴灌水肥用量。采用田间试验的方法,于2012年和2013年棉花生长季,设置5个N-P2O5-K2O施肥水平150-60-30、200-80-40、250-100-50、300-120-60、350-140-70 kg/hm2(分别记为F150、F200、F250、F300、F350)和3个灌溉水平(60%ETC:W1、80%ETC:W2、100%ETC:W3,ETC是作物蒸发蒸腾量)。结果表明,籽棉产量、水分利用效率和净收益的水肥耦合效应明显,60%ETC灌水水平显著抑制籽棉产量并降低净收益,100%ETC灌水水平能够显著提高籽棉产量和净收益,但水分利用效率低于60%ETC灌水水平。2012年灌水量为100%ETC且施肥量300-120-60 kg/hm2(N-P2O5-K2O)时籽棉产量最高,但净收益并未增加,2 a灌水量为100%ETC且施肥量250-100-50 kg/hm2(N-P2O5-K2O)时的净收益最高。二次回归分析结果表明,3种组合方式均可用于水肥多目标优化,其中乘法组合方式2 a水肥投入量差异更小且各目标值变化也更小,2012年灌水量92%ETC、施肥量278-111-56 kg/hm2(N-P2O5-K2O)以及2013年灌水量90%ETC、施肥量268-107-53 kg/hm2(N-P2O5-K2O)可作为籽棉产量、水分利用效率和净收益综合效益最大化的水肥管理策略。

基于净效益最大化的微电网电源优化配置

从成本效益分析角度,提出了基于净效益最大化的微电网电源优化配置模型。综合考虑电源投资、运行和维护、燃料购买等成本,以及节能、减排、降损、改善可靠性和延缓电网投资等效益,建立微电网年化净效益计算模型。以年化净效益为目标函数,计及储能单元充放电、微电网全年孤岛运行的充裕性、碳排放等约束条件,建立优化模型,并采用遗传算法进行求解。结果表明:该模型得到的电源配置方案能够取得较大社会经济效益,确保投资的最佳经济性,为微电网的规划和建设提供理论依据。

北京市新生儿乙肝疫苗免疫策略成本效益分析

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