关键词： Supply chain   Circular economy   Manure   Business ethics and sustainability   Input-output model   Biogas production   Circular business models   Sustainable bioenergy  

摘要： Purpose This paper aims to understand the implementation of a circular economic business where animal manure is used to produce biogas and alternative fertilizer in a regional network of manure suppliers and biogas producers and to reveal the impacts of five variables (manure quantity, transportation distance, manure dry content, manure price and manure discharge price) on the economic sustainability of manure-based biogas supply chains. Design/methodology/approach An enterprise input-output approach is used to model physical and monetary flows of the manure-based biogas supply chain. Computational experiments are performed on all variables to identify under which conditions the cooperation is beneficial for all actors. Findings The cooperation is profitable for a large-scale farm (>20,000 t/year) if biogas producer (b) pays farmer (f) to receive its manure (5 Euro/t) or if f sells manure for free and manure disposal costs are >10 Euro/t. Cooperation is always profitable for b if f pays b to supply its manure (5Euro/t). If b receives manure for free, benefits are always positive if b is a medium-large-scale plant (>20,000 t/year). For a small-scale plant, benefits are positive if manure dry content (MDC) is 12 per cent and transportation distance is 10 km. Originality/value The paper adds value to the biogas production research, as it makes holistic analysis of five variables which might change under different policy and geographical conditions. The investors in biogas production, suppliers and transportation companies can find correspondence to empirical findings for their own site-specific cases.

关键词： Social balance theory   Social networks   Ising model   Social temperature   Markov chain Monte Carlo   Maximum likelihood estimator  

摘要： We propose a dynamic economic model of networks where agents can be friends or enemies with one another. This is a decentralized relationship model in that agents decide whether to change their relationships so as to minimize their imbalanced triads. In this model, there is a single parameter, which we call social temperature, that captures the degree to which agents care about social balance in their relationships. We show that the global structure of relationship configuration converges to a unique stationary distribution. Using this stationary distribution, we characterize the maximum likelihood estimator of the social temperature parameter. Since the estimator is computationally challenging to calculate from real social network datasets, we provide a simple simulation algorithm and verify its performance with real social network datasets. (C) 2017 Elsevier B.V. All rights reserved.

摘要： Introduction : Multiple myeloma (MM) is a hematologic cancer of the plasma cells, which are found in the bone marrow. The early symptoms of MM are often vague and non-specific, such as fatigue, bone pain and back pain. These vague symptoms lead patients to present first to their primary care physician and often delay diagnosis resulting in progressive disease [***]. The median time for MM diagnosis (163 days) is longer than for most other hematologic cancers including leukemias and lymphomas [Howell et al, BMC Hematol, 2013]. Delayed diagnosis of MM is commonly associated with the development of chronic complications such as renal impairment, infections, neurological disease, bone disease and anemia [Kariyawasan et al, Q J Med, 2007]. Therefore, early detection and diagnosis of MM are essential to avoid downstream complications, and may significantly reduce the treatment costs associated with these complications. In the assessment of symptomatic patients, National Comprehensive Cancer Network (NCCN) practice guidelines recommend using three tests to maximize sensitivity and specificity: serum protein electrophoresis (SPE), serum immunofixation electrophoresis (SIFE) and serum free light chains (SFLC) [NCCN Multiple Myeloma Guidelines Version 3.2017]. However, physician compliance with these guidelines is hampered by the many different test options available and the low visibility of Myeloma on the list of possible causes for the primary care physician. In the current study, we modeled the effect of converting a hospital system over to guideline compliance in testing for Multiple Myeloma. Methods : A decision analytic model was developed to estimate the total costs and annual budget impact when using the guideline recommended panel for early diagnosis of MM patients. Using a US hospital (i.e., integrated delivery network [IDN]) model perspective, a decision algorithm was developed based on NCCN and IMWG clinical practice guidelines and further validated by

关键词： 粮食生产   农业化肥施用量   粮食播种面积   成灾面积   农业机械总动力   农业劳动力   OLS  

摘要： 农业是国民经济发展的基础,粮食是人类最基本的生活消费品,国家的粮食问题关系到国计民生。本文依据粮食产量现状,选取1983—2014年32年的数据,运用线性回归方法建立了影响粮食产量的计量经济模型,并借助Eviews软件对模型进行OLS等分析检验。结果表明,影响粮食生产的三大因素是粮食播种面积、农业化肥施用量、成灾面积,其中粮食播种面积的影响力最大。最后,本文提出了高粮食产量必须依靠技术,严格整治国土,合理施用化肥的建议。

关键词： 计量经济模型   面板数据   县级政府   道德风险   支出责任   地方政府   政府间财政关系   分税制财政体制  

摘要： （一）我国政府间财政关系简述。 1994年分税制财政体制改革是我国政府间财政关系的一次重大变革。作为一种新的制度安排,分税制财政体制在运行中表现出了一系列的积极效应。

关键词： 区域经济一体化   经济增长   空间计量经济模型  

摘要： 结合区域经济一体化下地区经济变化的相关数据以及经济地理分析方法,对传统计量模型进行改进,运用所选的数据进行建模分析,构建基于空间计量模型的区域经济一体化下经济增长情况的分析模型,并利用Matlab等软件,实现对模型的求解。借此探讨区域经济一体化在经济增长中发挥的作用以及产生的影响,并且根据模型检验的结果对经济变化情况进行内在分析,揭示了地区经济增长与区域经济一体化发展中的空间关联性、空间差异性以及区域经济一体化影响下的经济增长的变化过程,对于提升国家或地区的经济增长速度和缩小区域经济发展的差距有重要的意义。

关键词： 价值链   绿色创新效率   空间溢出效应   空间计量经济模型  

摘要： 基于价值链视角,运用超效率DEA模型测度2005—2014年中国30个省市工业企业绿色创新的整体及分阶段效率,并采用空间面板模型检验其空间溢出效应。结果表明:企业绿色创新的整体及分阶段效率均不高,区域差异明显;在地理距离权重矩阵下,整体及分阶段效率存在显著的正向溢出效应,而基于社会经济距离的外溢效应并不显著,且科技研发阶段的外溢效应强于成果转化阶段;开放度和产业结构与分阶段效率正相关,知识产权保护对本地区和邻区的科技研发分别产生了负向和正向效应。

关键词： 排土场   含金废石   Whittle软件   经济模型  

摘要： 由于前期矿山基建需要,将部分有经济价值的低品位金矿石临时堆放转存,等到金价上涨再回收利用,是矿山开采经常碰到的问题。通过对紫金山露采原含金废石堆场资源进行了补勘,生成Surpac资源模型,并利用Whittle软件建立经济模型,对堆场回采部位进行优化,在保证安全的前提下以经济利润最优的方式回收含金废石。

关键词： Economic Models  

摘要： This paper discusses nonparametric estimation of the distribution of random coefficients in a structural model that is nonlinear in the random coefficients. We establish that the problem of recovering the probability density function (pdf) of random parameters falls into the class of convexly-constrained inverse problems. The framework offers an estimation method that separates computational solution of the structural model from estimation. We first discuss nonparametric identification. Then, we propose two alternative estimation procedures to estimate the density and derive their asymptotic properties. Our general framework allows us to deal with unobservable nuisance variables, e.g., measurement error, but also covers the case when there are no such nuisance variables. Finally, Monte Carlo experiments for several structural models are provided which illustrate the performance of our estimation procedure.