天津市武清区大气O_3、NO_2和CO浓度变化特征研究

文章利用2014年天津市武清区大气污染物臭氧(O_3)、二氧化氮(NO_2)和一氧化碳(CO)的监测数据,分析研究武清区O_3及其前体物NO_2和CO等大气污染物浓度水平和变化特征。结果表明武清区O_3浓度水平呈现明显的季节变化特征。夏季O_3浓度为106μg·m~(-3),冬季浓度为28μg·m~(-3),主要与光化学反应在夏季比较强烈,冬季紫外强度和平均温度均较低,光化学反应较弱有关。2014年武清区大气中NO_2年均值为51μg·m~(-3),CO年均值为1.9 mg·m~(-3),冬季是NO_2和CO浓度最高的季节。     

电子商务背景下农产品F2F电商模式及其发展策略分析

由于信息交流不通畅、农产品价格波动频繁等原因,农产品电子商务在互联网技术发展带动下应运而生,各类农产品电商模式不断出现,其中农产品F2F电商模式就是最为重要的发展模式之一。文章通过归纳总结,从当前几种农产品电商模式特点出发,提出了农产品电商新模式——F2F(Farm to Family)。该文阐述了农产品F2F电商模式的运营模式内涵及当前发展现状,其次,剖析了F2F农产品模式的优劣点,最后根据前文分析,提出了积极构建农产品物流配送系统、积极培养农产品电子商务优秀人才、强化农产品的品质管理加快农产品电商发展的对策措施。     

Cost-effectiveness analysis of exenatide once-weekly versus dulaglutide,liraglutide, and lixisenatide for the treatment of type 2 diabetes mellitus: an analysis from the UK NHS perspective

Objective: To assess the cost-effectiveness of exenatide 2?mg once-weekly (EQW) compared to dulaglutide 1.5?mg QW, liraglutide 1.2?mg and 1.8?mg once-daily (QD), and lixisenatide 20?μg QD for the treatment of adult patients with type 2 diabetes mellitus (T2DM) not adequately controlled on metformin.

Methods: The Cardiff Diabetes Model was applied to evaluate cost-effectiveness, with treatment effects sourced from a network meta-analysis. Quality-adjusted life years (QALYs) were calculated with health-state utilities applied to T2DM-related complications, weight changes, hypoglycemia, and nausea. Costs (GBP £) included drug treatment, T2DM-related complications, severe hypoglycemia, nausea, and treatment discontinuation due to adverse events. A 40-year time horizon was used.

Results: In all base-case comparisons, EQW was associated with a QALY gain per patient; 0.046 vs dulaglutide 1.5?mg; 0.102 vs liraglutide 1.2?mg; 0.043 vs liraglutide 1.8?mg; and 0.074 vs lixisenatide 20?μg. Cost per patient was lower for EQW than for liraglutide 1.8?mg (?£2,085); therefore, EQW dominated liraglutide 1.8?mg. The cost difference per patient between EQW and dulaglutide 1.5?mg, EQW and liraglutide 1.2?mg, and EQW and lixisenatide 20?μg was £27, £103, and £738, respectively. Cost per QALY gained with EQW vs dulaglutide 1.5?mg, EQW vs liraglutide 1.2?mg, and EQW vs lixisenatide 20?μg was £596, £1,004, and £10,002, respectively. In the probabilistic sensitivity analysis, the probability that EQW is cost-effective ranged from 76–99%.

Conclusion: Results suggest that exenatide 2?mg once-weekly is cost-effective over a lifetime horizon compared to dulaglutide 1.5?mg QW, liraglutide 1.2?mg QD, liraglutide 1.8?mg QD, and lixisenatide 20?μg QD for the treatment of T2DM in adults not adequately controlled on metformin alone.     

Scale effects of R&D as reflected in earnings and returns

Using returns to scale as a conceptual foundation, we explore how R&D-related earnings performance and earnings variability depend upon firm size. We find that the positive association between the level of future earnings and R&D intensity increases with firm size, and that the positive association between the volatility of future earnings and R&D intensity decreases with firm size, consistent with R&D productivity increasing with scale. We also show that R&D scale is associated with lower market returns, consistent with the idea that R&D investment risk declines with scale.     

钙热还原TiO_2法制取金属钛的技术研究

文章对钙热还原TiO2法制取金属钛的技术进行了研究,结合现代先进检测方法系统地研究了钙热还原法制备金属钛的实验过程中所用添加剂CaCl2、反应温度和反应时间等因素对整个还原反应的影响。通过对还原时间、添加剂比例等因素控制的研究结果表明:将反应温度控制在1 200℃,无水CaCl2与TiO2的质量比为1誜3,反应时间为360 min的条件下进行还原反应,最终可得到呈团聚颗粒状的金属钛,能谱仪分析其平均纯度高达99.64%。     

关于X钢铁股份有限公司内部控制的案例分析

内部控制的主要方式包括组织规划控制、预算控制和实物控制。内部控制的完善对一个企业的健康发展来说特别重要。文中阐述了X钢铁在内部控制方面存在的问题,并针对X钢铁的内部控制自我评价报告的适当性发表意见,最终通过实践经历,分析内部控制对企业发展的重要性。     

2＋1模式下高职毕业论文中存在的问题及对策--以浙江汽车职业技术学院物流管理专业为例

文中从浙江汽车职业技术学院物流管理专业“2＋1”教学模式学出发，分析了造成毕业论文质量低下、抄袭严重的原因，并提出了对毕业论文管理模式改革的思考。     

A simple model of brain circulation

This paper analyzes the allocation of two types of individuals differentiated by talent between two countries where they choose to be workers or entrepreneurs. An equilibrium with international migration exists when countries' talent endowments are sufficiently different. It is consistent with one-way or two-way migration whether individuals are entrepreneurs or workers. Although allowing migration increases domestic welfare in one country and decreases it in the other, it is always supported by majority voting in both countries.     

论二语语用发展研究认知路向

“未来的研究需从心理学的不同角度，包括认知理论和社会文化理论考虑学习者的二语语用习得。”Kasper和Rose的这一设想，不仅为二语语用发展研究提出了新思路，也提出了挑战。建立在语用普遍性基础之上的二语语用发展研究，在继承传统语用研究成果的同时，汲取体验认知语用的研究成果，将概念能力发展和隐喻能力发展作为一种新的研究路向。这既有必要，也有可能。     

Adoption Dynamics in Buyer-Side Exchanges

The purpose of this paper is to understand buyer/seller adoption dynamics in independent, buyer-side B2B exchanges. In a stylized model, we assume that the main role of the exchange is to reduce search costs for buyers. Buyers and sellers enter or exit the exchange based on the relative economic surplus (loss) they receive inside vs. outside the exchange. We contrast two situations: one where participants' switching cost to join the institution is negligible and another, in which it is significant. In an extension, we also explore the impact of buyer/seller heterogeneity on adoption dynamics. We have three key findings with relevant implications for practice. First, we find that the general view that demand and supply (so-called liquidity) either grows or shrinks in the marketplace may not hold. In the presence of switching costs, the exchange can evolve to a stable state with only partial market participation. Second, our results suggest that the exchange is better off subsidizing buyers as opposed to sellers in order to achieve the so-called critical mass, beyond which there is full participation. Finally, we find that while in general, minor buyers of the industry have more incentive joining the exchange, when the fixed participation fee of the exchange is high, it is major buyers who are likely to join first. For sellers, this is not the case: minor sellers are always more keen in participating in a buyer-side exchange.