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321.
Deregulation of U.S. Airline Industry may have lowered systematic risk because pricing freedom and route flexibility improved airline management reaction to various economic conditions. Reduced systematic risk offers lower cost of equity capital for the industry as a whole as well as for individual carriers. Previous research has had mixed results in identifying a relationship between deregulation and airline industry cost of capital. This study plots airline industry Beta coefficients across the years 1963 to 1987 and clears up previously conflicting research findings. Beta coefficients had been falling since the fuel crisis of 1974 and continued to fall through 1980. Fluctuations since deregulation have been relatively minor and systematic risk has leveled off at a significantly lower value than before deregulation. Studies which concentrate on the fluctuation in Beta since 1978 are dependent on the exact time period of analysis, and their conclusions that deregulation raised or lowered systematic risk are likewise suspect. A broader view of systematic risk changes in the deregulatory era shows airline Betas peaking from 1971 to 1973 and a gradual decrease as deregulation was being discussed, implemented, and legally mandated. This gradual decline from 1974 to 1980 may be attributed to such factors as fuel prices, interest rates, general inflation as well as deregulation. In any case systematic risk of the U.S. Airline industry has been lower since deregulation than in decades before.  相似文献   
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齐岳山隧道注浆必要性的数值分析与论证   总被引:4,自引:1,他引:3  
根据万宜铁路齐岳山隧道的地质条件建立隧道渗流场的分析模型,模型贯彻“以堵为主,限量排放”的原则。考虑到排水盲管的作用,将隧道内表面设置为浸出面,及时将隧道内的渗水排出。模型真实的模拟了溶洞、暗河、断层对渗流场的影响。着重考虑了隧道在注浆与不注浆两种工况条件下的渗流情况。分别统计了两种工况下的水压力与渗水流量,最终论证了注浆的必要性与重要性。  相似文献   
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With the development of door-to-door intermodal services and the advent of just-in-time supply systems, punctual delivery of cargoes is more than ever a priority both for shippers and for shipowners. This paper is about the incidence of delay in transportation, particularly in the marine mode, and its legal and commercial consequences.

The fundamental legal obligations of marine carriers have always included delivery with dispatch. Thus the law would seem to support the commercial expectations of shippers for reliable performance. The authors discuss the nature of these obligations, investigate their adequacy under modern conditions of trade and report on a survey of Canadian shippers and consignees.

The authors conclude that there appears to be a divergence in the toleration of delay, but that few of the Canadian companies suffering unacceptable delays received, or even sought, financial compensation and none of them planned to do more. The authors speculate about their reasons for absorbing the losses incurred through unacceptable delays. The evidence from the survey is that shippers, in spite of their dissatisfaction with the resolution or outcome of incidents of unacceptable delay, are loath to seek compensation through legal means, but instead prefer to resort to a range of commercial actions.  相似文献   
326.
本文报道了丹参注射液在大鼠急性胰腺炎模型中对胰腺组织的保护作用,复方丹参注射液能明显减轻实验大鼠胰腺的出血及坏死程度,降低大鼠的死亡率。血清超氧化物歧化酶(SOD)的检测结果:丹参保护组较急性胰腺炎(AP)组SOD的含量明显降低。提示丹参注射液通过改善胰腺的微循环,提高胰腺组织对缺氧的耐受性,减少氧自由基的产生,而最终减轻胰腺的病变程度。  相似文献   
327.
论述财神庙隧道磨沟斜井和大沟横洞低瓦斯工区设计主要从超前探测、结构支护设计和施工等方面考虑,提出瓦斯监测、硫化氢监测和安全防护、施工通风等技术措施;提出初期支护、二次衬砌、瓦斯隔离层均采用全封闭结构,增强衬砌结构抗渗性,可有效防止瓦斯、硫化氢溢出等结论和施工现场应建立健全的瓦斯隧道施工安全管理制度等建议。  相似文献   
328.
The freshwater plume in the western Gulf of Maine is being studied as part of an interdisciplinary investigation of the physical transport of a toxic alga. A field program was conducted in the springs of 1993 and 1994 to map the spatial and temporal patterns of salinity, currents and algal toxicity. The observations suggest that the plume's cross-shore structure varies markedly as a function of fluctuations in alongshore wind forcing. Consistent with Ekman drift dynamics, upwelling favorable winds spread the plume offshore, at times widening it to over 50 km in offshore extent, while downwelling favorable winds narrow the plume width to as little as 10 km.Using a simple slab model, we find qualitative agreement between the observed variations of plume width and those predicted by Ekman theory for short time scales of integration. Near surface current meters show significant correlations between cross-shore currents and alongshore wind stress, consistent with Ekman theory. Estimates of the terms in the alongshore momentum equation calculated from moored current meter arrays also indicate a dominant Ekman balance within the plume. A significant correlation between alongshore currents and winds suggests that interfacial drag may be important, although inclusion of a Raleigh drag term does not significantly improve the alongshore momentum balance.  相似文献   
329.
卸船机结构庞大,受力复杂,工作环境恶劣,现场试验难以组织.为减少试验成本,根据相似原理,运用量纲分析法研制了2 250 t/h桥式抓斗卸船机的相似模型,几何尺寸比例为1:40.通过模型应变检测试验,得出俯仰梁与前拉杆上5个测点在满载荷的抓斗从起升位置运动至卸料位置过程中的应力应变呈现逐渐变小的规律,实验结果与有限元分析计算结果对比基本吻合.研究结果为卸船机安全性设计和维修策略研究提供了理论依据和试验数据.  相似文献   
330.
目的 定位小鼠致聋基因 ,识别决定其性状的有关突变 ,为人类耳聋基因研究提供动物模型。方法 利用全基因组扫描来定位名为hml可致小鼠听力丧失突变基因。结果 ①hml基因定位在小鼠 10号染色体上 ,距中心粒约4 3cM处。根据已知的鼠 人同源同线性特点 ,提示人的同源基因位于 12 q2 2 -q2 4 ;②获得了 2 5个多态性微卫星标记 ,通过高分辨的小鼠图谱将 3个已知人类基因进行了正确排列 ,并将hml侯选基因限定在一个 5 0 0kb的区域内。  相似文献   
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