公司债务期限结构影响因素的实证分析

本文以上市公司板面数据及横截面数据为基础,利用混合时间序列回归、横截面回归和固定效果回归等方法,对影响我国上市公司债务期限结构的因素进行了实证检验。结果发现,除契约成本假说中成长机会外,绝大部分因素的检验结果与预期一致,进而验证了其适用性;经验证据不支持信息不对称假说;对税负假说相关因素的检验结果表现出不确定性;期限匹配假说得到了支持。研究还证明,具有较少自由现金流量、杠杆水平较高、规模大、受到管制和资产期限长的公司具有更多的长期债务。     

马尾口岸蝇类生物多样性和携带病原微生物情况的研究

目的全面掌握马尾口岸蝇类的种群分布及季节消长变化,分析不同生境和地点蝇类携带病原微生物的差别,对相关疾病的流行风险进行评估。方法根据马尾口岸地理分布和港口类型,2007年7月至2008年6月间,抽取8个监测点7个不同生境实施为期1年的蝇类本底调查,按生境分类对携带病原微生物进行检测。结果捕获蝇类49579只,年平均密度74.67只/笼.日,隶属4科22属36种,比2004年多19种,其中4种未见在福州分布记录,大头金蝇为优势种群。垃圾堆蝇密度最高,高于荒地、居民室外和食堂。大裕堆场和中钢码头蝇密度较高,高于居委会、青州堆场、局本部和闽鑫物流。5至10月份捕获的蝇数占总数的94.57%,出现了9月和5月的双峰。蝇类体内、外均虽未检出痢疾杆菌、伤寒杆菌和霍乱弧菌等强致病菌,但普遍检出了变形杆菌、铜绿假单胞菌和肺炎克雷伯菌等,以及可引起食物中毒的病原菌如金黄色葡萄球菌、变形杆菌等,个别样本检出气单胞菌和小肠耶尔森氏菌。部分蝇体内检出柯萨奇病毒和轮状病毒（A组）。结论马尾口岸蝇种丰富,比4年前有了较大增长,出现了4种输入性蝇种,蝇类体表和体内携带的病毒,可能引起食物中毒及其他肠道传染病传播的风险。     

对虾白斑综合征病毒表面抗原基因免疫保护性的研究

将对虾白斑综合征病毒（White Spot Syndrome Virus,W SSV）的VP19、VP28基因融合克隆入pVAX1.0真核表达载体制备成多价 DNA 疫苗,并用构建的 DNA 疫苗制备成饲料免疫实验对虾,用RT-PCR 检测DNA 疫苗在对虾体内的表达,同时比较构建的多价DNA 疫苗与VP19、VP28单价DNA 疫苗对抗W SSV的保护率。结果显示构建的DNA疫苗有抗W SSV免疫保护性,且pVAX1.0-VP19-VP28多价DNA 疫苗保护率高于单价疫苗。     

昆津病毒和巴马哈森林病毒双重RT—PCR检测方法的建立

[目的]建立昆津病毒和巴马哈森林病毒双重RT-PCR检测方法。[方法]利用Beacon Designer7．0软件设计引物,以人工合成昆津病毒巴马哈森林病毒E基因的片段作为模板,验证该方法的灵敏度及特异性。[结果]最低检出限：昆津病毒1．83106copies／μL,巴马哈森林病毒2．02×106copies／μL。[结论]建立的昆津病毒和巴马哈森林病毒双重RT-PCR检测方法具有灵敏度高、特异性好等特点,适合于昆津病毒和巴马哈森林病毒的快速检测。     

负债代理成本影响因素实证分析——来自我国上市公司的证据

本文以我国上市公司面板数据及横截面数据为基础,运用线性回归分析对影响公司负债代理成本的因素进行了实证检验。结果发现,负债代理成本与债务期限结构、公司规模、财务灵活性及盈利能力的变化显著负相关;与公司未来成长性、资产期限、负债规模的变化显著正相关。     

A simple agent model of an epidemic

This paper presents an agent model that simulates the spread of an infection in a population. The epidemic depicted could be any attribute that is passed from a one person to others in society, for example, a disease, an idea or belief, a fad, a market or a behavioral pattern. The model was constructed to study the sensitivity of factors such as virility of the infectious agent, the “reach” of the vector and the density of the population in which the epidemic takes place. A further goal was to begin the development of a general-purpose forecasting model based on the use of agents. The model and its results are presented in this paper.     

阴道镜诊断宫颈人乳头状瘤病毒感染的临床分析

目的:探讨阴道镜在宫颈人乳头状瘤病毒感染诊断中的临床应用价值。方法:2006年1月至2007年12月,在本院妇科门诊行阴道镜检查的患者,以其宫颈组织学检查结果为标准,对阴道镜检查结果进行分析。结果:病理学级别越高,宫颈SPI感染阳性率越高。阴道镜诊断宫颈SPI的敏感性为84.8%,特异性为97.5%,阳性预测值为70.9%,阴性预测值为98.9%。结论:阴道镜对诊断宫颈SPI有较重要的临床价值。     

Economic and clinical contributions of an antimicrobial barrier dressing: a strategy for the reduction of surgical site infections

Abstract

Objective:

In patients at risk of surgical site infection (SSI), there is evidence that an antimicrobial barrier dressing (Acticoat) applied immediately post-procedure is effective in reducing the incidence of infection. The objective of this study was to assess when it is appropriate to use an antimicrobial barrier dressing rather than a post-operative film dressing, by evaluating the net cost and budget impact of the two strategies.

Methods:

An economic model was developed, which estimates expected expenditure on dressings and the expected costs of surgical site infection during the initial inpatient episode, based on published literature on the pre-discharge costs of surgical infection and the efficacy of an antimicrobial barrier dressing in preventing SSI.

Results:

At an SSI risk of 10%, an antimicrobial barrier dressing strategy is cost neutral if the incidence of infection is reduced by at least 9% compared with a post-operative film dressing. At 35% efficacy, expenditure on dressings would be higher by £30,760 per 1000 patients, and the cost of treating infection would be lower by £111,650, resulting in a net cost saving of £80,890. The break-even infection risk for cost neutrality is 2.6%.

Limitations:

Although this cost analysis is based on published data, there are limitations in methodology: the model is dependent on and subject to the limitations of the data used to populate it. Further studies would be useful to increase the robustness of the conclusions, particularly in a broader range of surgical specialities.

Conclusions:

A strategy involving the use of an antimicrobial barrier dressing in patients at moderate (5–10%) or high (>10%) risk of infection appears reasonable and cost saving in light of the available clinical evidence.     

快速检测西尼罗病毒胶体金免疫层析试纸条方法的建立

[目的]建立一种能快速区分、简便诊断西尼罗病毒感染的胶体金免疫层析试纸条方法。[方法]采用柠檬酸三钠还原法制备胶体金颗粒,标记西尼罗病毒NS1蛋白,采用双抗原夹心法制备胶体金免疫层析试纸条,对试纸条进行特异性和敏感性评价。[结果]该试纸条可在15min之内完成检测;在敏感性上,该试纸条对阳性血清的检测较美国Focus公司商品化的ELISA试剂盒检测低1个滴度;对89份阴性血清进行检测,试纸条检出9份阳性,ELISA试剂盒检出3份阳性,两种检测的符合率为86.52%,特异性为89.89%。[结论]初步建立了一种可以用于现场快速检测西尼罗病毒的胶体金免疫层析方法,为进一步大规模应用奠定了基础。     

计算机病毒及其防治

本文首先简介计算机病毒的产生和发展以及计算机病毒的定义和分类,然后介绍DOS操作系统环境下的计算机病毒的特点及危害,最后从计算机安全及实际科研生产中计算机的应用角度论述计算机病毒的防治方法。