医疗器械库存策略模型的研究

针对医疗器械库存管理的现状,建议采用Silver Meal算法、供应商库存管理（VMI）库存策略,分别对低值、高值器械进行管理,来降低整个医疗物资供应链的库存成本,减少＂牛鞭效应＂的影响,提高供货及时性和准确性,大大改善供应链运作效率。     

一个新的养分效应数学模型

在养分效应研究中,多采用二次抛物线模型,从容（1991）在米氏方程的基础上提出一个改进抛物线模型,这两种模型都是对称性模型,也即是把养分正负效应的速率视为相同,而大多数实际情形并非如此．本文建立了一个反映养分效应普遍现象的非对称性模型,两个应用实例表明新模型较之原来的模型无论在拟合度（残差平方和）还是在生物学意义方面都具有明显的优越性．     

Crow-Kimura模型中位点突变率对误差阈的随机效应

为了补充Eigen模型和Crow-Kimura模型的随机效应研究,Crow-Kimura模型中的位点突变率被处理成高斯分布随机变量,从而研究误差阈值的特征以及误差阈值的扩展与随机突变率涨落强度之间的关系. 准物种浓度和群体序参数分析表明,在位点突变率涨落较大时,误差阈值不再是相变点,而是平滑的转变区域. 定量分析表明,随机Crow-Kimura模型中转变区宽度与涨落强度之间的关系是非线性的. 将Crow-Kimura模型与Eigen模型的随机特征进行比较发现,在两个模型中适应值随机化使得转变区域的宽度和随机变量涨落强度之间的关系是线性的,而位点突变率随机化中两者的关系是非线性的（指数）. 对于随机化的Crow-Kimura模型,适应值随机化与位点突变率随机化引起的误差阈扩展效应相当. 对于随机Eigen模型,误差阈的扩展效应则主要是由位点突变率的随机化引起的. 之后,本文概述了Eigen模型和Crow Kimura模型中适应值和位点突变率随机化对误差阈值随机效应的影响,并讨论了上述结果对抗病毒策略、癌症治疗和动植物育种的重要意义.     

电针对老年性痴呆大鼠外侧隔核AChE阳性神经元表达影响

目的研究电针对老年性痴呆（AD）模型大鼠外侧隔核（LSN）乙酰胆碱酯酶（AChE）阳性神经元表达的影响。方法以D-半乳糖腹腔注射和Aβ1-40海马注射诱导形成老年性痴呆大鼠模型,电针＂大椎＂、＂肾俞＂、＂太溪＂三穴,以免疫组织化学法检测大鼠LSN中AChE阳性神经元的表达。结果与模型组相比,电针组AChE阳性神经元数量明显增多,具有显著统计学意义。结论电针可能通过增加大鼠LSN中AChE阳性神经元的表达,进而发挥抗老年性痴呆的作用。     

为什么近年有些教材将鸟类归入“爬行纲”

近年国外一些动物学教材取消了＂鸟纲＂,将鸟类归入＂爬行纲＂,这是一种学术观点的反映,并不是新的提法。由于鸟类与爬行动物的亲缘关系非常密切,在躯体结构和功能方面的特征有很多方面与爬行类动物极为相似,以至在100多年前就有人认为鸟类是＂具有羽毛的爬行动物＂,并将鸟类与爬行类一起归入＂蜥形类（Sauropsida）＂。     

拓扑差异物体的构型处理：一项脑电研究

根据陈霖的拓扑知觉理论,在视觉感知中,拓扑差异的检测要快于局部特征的检测.本研究组认为,这一现象可能是对有＂洞＂图形和无＂洞＂图形的感知差异所造成的.本文旨在检验这两类图形所存在的知觉差异究竟是什么.利用脑电（ERP）技术,测量＂洞＂和＂非洞＂图形所引起的视觉诱发电位（VEP）,探究＂洞＂和＂非洞＂的区别.两类图形引起的VEP区别体现在N170上,＂洞＂图形的反转使得N170的潜伏期显著变化,而＂非洞＂图形的反转不会引起N170潜伏期的变化.人脸与非人脸物体的反转引起的N170变化与本结果相似.本研究认为,对＂洞＂的感知更偏向于整体加工,而对于＂非洞＂则更偏向于特征加工.     

雌激素膜受体介导的非基因组效应

雌激素受体（estrogen receptor,ER）是固醇类激素受体蛋白超家族的成员之一,分布于许多组织,介导了大部分已知的雌激素效应.ER主要定位于胞质中,但是近些年的研究发现在部分组织的细胞膜上也存在雌激素受体,称为“膜受体（mER）”.ER在其配体雌二醇（E2）的诱导下,可以通过“基因组”和“非基因组”两种方式介导大部分的生理效应,胞质中的ER可与DNA反应元件直接作用产生基因组效应,而mER主要通过信号分子介导雌激素的非基因组效应.该文介绍ER的结构、ER介导的非基因组效应的生理功能以及前景展望.     

基于收益共享契约的农产品供应链合作优化模式研究

通过引入“农户（合作社）为提高每单位农产品质量而付出的努力成本”这一变量以及收益共享契约思想,选用国内农产品供应链常见的“农超对接”模式为研究对象,构建了农户（合作社）和超市单独决策时的利润分配模型、供应链合作优化时的利润分配模型以及基于收益共享契约的供应链合作优化模型。通过算例分析,发现建立基于收益共享契约的农产品供应链合作优化模式,有利于激励农户（合作社）为提高农产品质量而付出努力、提高农产品供应链各方的收益水平、降低农产品价格水平,有利于提升农产品质量安全状况。     

类别验证任务中否定加工的ERP研究

有研究提出了否定加工的两阶段模拟假说,认为否定加工的第一阶段是模拟被否定的状态,第二阶段是整合否定以模拟真实状态.为了对该假说进行检验,本研究采用ERP技术探讨了20名被试完成类别验证任务时的脑内时程动态变化.任务有4种条件：肯定类别对（例如,蔬菜-白菜）,肯定无关对（例如,蔬菜-蜜蜂）,否定类别对（例如,蔬菜-蜜蜂）和否定无关对（例如,蔬菜-白菜）.其中类别上画有一横线表示＂不是该类别的事物＂,例如,蔬菜表示＂不是蔬菜＂.结果表明,否定类别对比否定无关对和肯定类别对都引发了更负的N400,这说明,否定加工中建立了被否定状态的表征,支持了两阶段模拟假说.此外,肯定类别对比否定类别对引发了更正的LPC,这一结果揭示了两阶段模拟假说中第二阶段即整合否定模拟真实状态的神经机制.可能是因为肯定类别关系的加工涉及再认和记忆信息的提取,而否定类别关系的加工如两阶段模拟假说所预期的包含两个阶段,涉及推理过程,因而前者比后者引发了更正的LPC.     

假互补肽核酸及其分子生物学效应

假互补肽核酸（pseudocomplementary peptide nucleic acids,pcPNAs）是肽核酸（peptide nucleic acids,PNA）的一种衍生物,通过碱基修饰可以使pcPNAs 同时与双链DNA两条链中相应的靶序列结合;而在pcPNAs识别靶序列并结合时,pcPNAs自身两条链间由于空间位阻作用,不会自身互补结合. pcPNAs与DNA、RNA甚 至肽核酸相比具有独特的杂交特性,因此具有非常广泛的分子生物学效应.本文就pcPNAs寡聚体的结构、与核酸杂交的特点及杂交模式,分子生物学效应以及应用等 方面进行介绍.     

The impact of ordering behavior on order-quantity variability: a study of forward and reverse bullwhip effects

We introduce the concept of the reverse bullwhip effect (RBWE), which can be caused by supply disruptions. In the RBWE, order variability increases as one moves downstream in the supply chain, and therefore the RBWE is the opposite of the classical bullwhip effect (BWE). We test our conjecture that disruptions cause the RBWE using both a live “beer game” experiment and a simulation study. In the beer game, we find that players modify their ordering behavior during disruptions, and that these modifications cause the RBWE. We confirm this cause of the RBWE under a broad range of settings using discrete-event simulation. Our results demonstrate that supply uncertainty (in the form of random disruptions) and an overweighting of the supply line cause the RBWE. They also confirm previous studies showing that demand uncertainty and an underweighting of the supply line cause the BWE. Moreover, our study provides guidance for models of operational disruptions by incorporating human reactions to disruptions.     

Ecological Supply Chains Performance Evaluation and Disruption Risk Management Strategies

This article presents the ecological supply chain (ESC) model and demonstrates its benefits. The causes that make an ESC vulnerable to disruption risks are analyzed; the objective is to balance the cost and the disruption risk. Also, it provides supply management strategies, demand management strategies, product management strategies, and information management strategies. Practice in China is reviewed. Based on exergoeconomics theory, the ESC is regarded as a huge energy system providing new perspective. The sustainability of the ESC system is discussed under the circumstances of exergoeconomics. The metric of “system negative environment effect” is introduced to measure ESC system performance. Finally, a real case example is used to illustrate the models and get some conclusions.     

线粒体呼吸链膜蛋白复合体的结构

线粒体作为真核细胞的重要“能量工厂”,是细胞进行呼吸作用的场所,呼吸作用包括柠檬酸循环和氧化磷酸化两个过程,其中氧化磷酸化过程的电子传递链（又称线粒体呼吸链）位于线粒体内膜上,由四个相对分子质量很大的跨膜蛋白复合体（Ⅰ、Ⅱ、Ⅲ、和Ⅳ）、介于Ⅰ／Ⅱ与Ⅲ之间的泛醌以及介于Ⅲ与Ⅳ之间的细胞色素c共同组成。线粒体呼吸链的功能是进行生物氧化,并与称之为复合物V的ATP合成酶（磷酸化过程）相偶联,共同完成氧化磷酸化过程,并生产能量分子ATP。线粒体呼吸链的结构生物学研究对于彻底了解电子传递和能量转化的机理是至关重要的,本文分别论述线粒体呼吸链复合体Ⅰ、Ⅱ、Ⅲ和Ⅳ的结构,并跟踪线粒体呼吸链超复合体的结构研究进展。     

Life Cycle Attribute Assessment

Practitioners of life cycle assessment (LCA) have recently turned their attention to social issues in the supply chain. The United Nations life cycle initiative's social LCA task force has completed its guidelines for social life cycle assessment of products, and awareness of managing upstream corporate social responsibility (CSR) issues has risen due to the growing popularity of LCA. This article explores one approach to assessing social issues in the supply chain—life cycle attribute assessment (LCAA). The approach was originally proposed by Gregory Norris in 2006, and we present here a case study. LCAA builds on the theoretical structure of environmental LCA to construct a supply chain model. Instead of calculating quantitative impacts, however, it asks the question “What percentage of my supply chain has attribute X?” X may represent a certification from a CSR body or a self‐defined attribute, such as “is locally produced.” We believe LCAA may serve as an aid to discussions of how current and popular CSR indicators may be integrated into a supply chain model. The case study demonstrates the structure of LCAA, which is very similar to that of traditional environmental LCA. A labor hours data set was developed as a satellite matrix to determine number of worker hours in a greenhouse tomato supply. Data from the Quebec tomato producer were used to analyze how the company performed on eight sample LCAA indicators, and conclusions were drawn about where the company should focus CSR efforts.     

Multi-objective fuzzy design of closed-loop supply chain network considering risks and environmental impact

Due to governmental, environmental, and economic concerns, the closed-loop supply chain network has attracted the attention of researchers. In this article, a multiproduct, multi-echelon, and multi-objective closed-loop supply chain network model in a fuzzy environment is proposed. The forward supply chain network includes raw material suppliers, virgin material suppliers, plants, distribution centers, and customer zones, while the reverse supply chain network is composed of customer zones, collection centers, refurbishing centers, dismantling centers, and decomposition centers. The objectives of this model are to minimize the total cost, waste, carbon dioxide, and risks. In order to solve the proposed model, a fuzzy multi-objective optimization method is used. A numerical example validates and verifies the practicability of the fuzzy model and solution method, and demonstrates the proposed model and method can be applied to solve real world problems.     

A mathematical model to design a lignocellulosic biofuel supply chain system with a case study based on a region in Central Texas

This study formulates a model to maximize the profit of a lignocellulosic biofuel supply chain ranging from feedstock suppliers to biofuel customers. The model deals with a time-staged, multi-commodity, production/distribution system, prescribing facility locations and capacities, technologies, and material flows. A case study based on a region in Central Texas demonstrates application of the proposed model to design the most profitable biofuel supply chain under each of several scenarios. A sensitivity analysis identifies that ethanol (ETOH) price is the most significant factor in the economic viability of a lignocellulosic biofuel supply chain.     

Biomass feedstock preprocessing and long‐distance transportation logistics

Biomass‐based biofuels have gained attention because they are renewable energy sources that could facilitate energy independence and improve rural economic development. As biomass supply and biofuel demand areas are generally not geographically contiguous, the design of an efficient and effective biomass supply chain from biomass provision to biofuel distribution is critical to facilitate large‐scale biofuel development. This study compared the costs of supplying biomass using three alternative biomass preprocessing and densification technologies (pelletizing, briquetting, and grinding) and two alternative transportation modes (trucking and rail) for the design of a four‐stage biomass–biofuel supply chain in which biomass produced in Illinois is used to meet biofuel demands in either California or Illinois. The BioScope optimization model was applied to evaluate a four‐stage biomass–biofuel supply chain that includes biomass supply, centralized storage and preprocessing (CSP), biorefinery, and ethanol distribution. We examined the cost of 15 scenarios that included a combination of three biomass preprocessing technologies and five supply chain configurations. The findings suggested that the transportation costs for biomass would generally follow the pattern of coal transportation. Converting biomass to ethanol locally and shipping ethanol over long distances is most economical, similar to the existing grain‐based biofuel system. For the Illinois–California supply chain, moving ethanol is Biomass‐based biofuels have gained attention because they are renewable energy sources that could facilitate energy independence and improve rural economic development. As biomass supply and biofuel demand areas are generally not geographically contiguous, the design of an efficient and effective biomass supply chain from biomass provision to biofuel distribution is critical to facilitate large‐scale biofuel development. This study compared the costs of supplying biomass using three alternative biomass preprocessing and densification technologies (pelletizing, briquetting, and grinding) and two alternative transportation modes (trucking and rail) for the design of a four‐stage biomass–biofuel supply chain in which biomass produced in Illinois is used to meet biofuel demands in either California or Illinois. The BioScope optimization model was applied to evaluate a four‐stage biomass–biofuel supply chain that includes biomass supply, centralized storage and preprocessing (CSP), biorefinery, and ethanol distribution. We examined the cost of 15 scenarios that included a combination of three biomass preprocessing technologies and five supply chain configurations. The findings suggested that the transportation costs for biomass would generally follow the pattern of coal transportation. Converting biomass to ethanol locally and shipping ethanol over long distances is most economical, similar to the existing grain‐based biofuel system. For the Illinois–California supply chain, moving ethanol is $0.24 gal^?1 less costly than moving biomass even in densified form over long distances. The use of biomass pellets leads to lower overall costs of biofuel production for long‐distance transportation but to higher costs if used for short‐distance movement due to its high capital and processing costs. Supported by the supply chain optimization modeling, the cellulosic‐ethanol production and distribution costs of using Illinois feedstock to meet California demand are $0.08 gal^?1 higher than that for meeting local Illinois demand.     

Exploring the emergence of a biojet fuel supply chain in Brazil: An agent‐based modeling approach

The aviation industry accounts for more than 2% of global CO₂ emissions. Biojet fuel is expected to make an essential contribution to the decarbonization of the aviation sector. Brazil is seen as a key player in developing sustainable aviation biofuels owing to its long‐standing experience with biofuels. Nevertheless, a clear understanding of what policies may be conducive to the emergence of a biojet fuel supply chain is lacking. We extended a spatially explicit agent‐based model to explore the emergence of a biojet fuel supply chain from the existing sugarcane–ethanol supply chain. The model accounts for new policies (feed‐in tariff and capital investment subsidy) and new considerations into the decision making about production and investment in processing capacity. We found that in a tax‐free gasoline regime, a feed‐in tariff above 3 R$/L stimulates the production of biojet fuel. At higher levels of gasoline taxation (i.e., 2.46 R$/L), however, any feed‐in tariff is insufficient to ensure the production of biojet fuel. Thus, at these levels of gasoline taxation, it is needed to introduce regulations on the production of biojet fuel to ensure its production. Given the current debate about the future direction of the biofuel policy in Brazil, we recommend further research into the effect of market mechanisms based on greenhouse gas emissions on the emergence of a Brazilian biojet fuel supply chain.     

内蒙古锡林郭勒盟草原产草量动态遥感估算

草原产草量的监测是草地资源空间动态研究的重要衡量指标,是草地资源合理利用和载畜平衡监测的重要依据.基于371个样地调查数据和2005～2009年的MODIS-NDVI遥感数据,建立地面样方的产草量与遥感数据的关系模型,模拟分析了内蒙古锡林郭勒盟草原产草量的时空分布.结果表明：（1）建立的各模型方程均有较好的相关关系,其中幂函数的相关关系最优,通过预留样方数据的验证,模型精度为78%,幂函数模型作为遥感估测应用可行;（2）锡林郭勒盟草原的产草量5年平均为3455万吨,折合干草总量为1112万吨,平均单产为567.23kg/hm2,草原产草量的空间分布呈东高西低的格局;（3）2005～2009年,锡林郭勒盟草原产草量有明显的波动,干草变化范围为800～1400万吨,变异系数为20.42%;（4）不同草地类型的产草量及其年际间变化存在较大的差异,荒漠类草原产草量低,年际间变化较大;草甸类草原产草量高,年际间变化相对较小.草原产草量的时空变化还与降水量、气温等主要气候因素关系密切,特别是受降水量的时空变化影响显著.研究结果可以为中国草地资源的保护及合理利用提供参考依据.