进近着陆运输飞行事故原因及预防对策研究

进近着陆是最容易发生重大运输飞行事故的阶段,笔者对1980—1996年发生的民航运输飞行进近着陆事故进行了统计分析。结果表明:事故的主要原因是人为因素和环境因素,事故结果主要为飞机失去控制和可控飞行撞地的结果,飞机撞地后起火往往造成机组人员和乘客大量伤亡;加强研究民航飞行安全中的人为因素控制,改善进近着陆的环境系统,重视机场应急计划的编制和应急救援的模拟演练等措施,对降低进近着陆阶段的飞行事故次数、改善航空运输安全和减少人员伤亡具有重要意义。     

基于人的认知可靠性(HCR)模型的人因操作失误研究

以人的认知可靠性(HCR)模型为指导,选择包含技能型、规则型和知识型3种认知类型,结合大连化工集团公司影响运行安全的17个异常事件,对54名操纵员的时间响应状况和允许操作时间进行录像、记录与分析;依据IAEA提供的指标[1],找出操纵员在生产过程中可能出现的操作失误类别及其可能造成的危害;基于3参数威布尔模型推导出操纵员操作响应失误概率模型,并从人机工程学角度提出了具体预防事故的安全对策措施。结果表明,基于HCR模型的大化集团公司操纵员的人因操作失误模型实用、有效,为实现操作者与机器系统相协调的目标、正确评估操作着实时操作的响应时间提供了重要参考依据。     

几种化合物对温石棉诱导入胚肺细胞蛋白激酶C活性的影响

为了探讨几种化合物对温石棉诱导人胚肺（HEL）细胞蛋白激酶C（PKC）活性的影响，该研究用不同浓度的柠檬酸铝、混合稀土或亚硒酸钠溶液浸泡温石棉1小时后，再将其与HEL细胞共同孵育24小时，测定了HEL细胞胞浆和胞膜中PKC的活性。其结果显示：随着石棉剂量的增加，HEL细胞胞浆和胞膜中的PKC活性逐渐升高，均呈明显的剂量依赖性；经3种化合物预处理的石棉，其所诱导的HEL细胞胞浆和胞膜中的PKC活性均明显低于未处理温石棉组。笔者提示：温石棉可能通过改变细胞内PKC的活性进一步促进肿瘤的发生；用3种化合物预处理温石棉，均可抑制温石棉对HEL细胞PKC活性的诱导作用。     

Prenatal diagnosis of Niemann–Pick diseases types A,B and C

Prenatal diagnosis of Niemann–Pick disease types A and B is routinely accomplished by sphingomyelinase assay. For Niemann–Pick type C disease, demonstration of an abnormal intracellular cholesterol trafficking is a complex procedure, and mutational analysis (NPC1 or NPC2/HE1 gene), whenever feasible, represents a major advance. Copyright © 2002 John Wiley & Sons, Ltd.     

Increased fetal nuchal translucency at 11–14 weeks

Nuchal translucency (NT) is the sonographic appearance of a subcutaneous collection of fluid behind the fetal neck. The measurement of fetal NT thickness at the 11–14-week scan has been combined with maternal age to provide an effective method of screening for trisomy 21; for an invasive testing rate of 5%, about 75% of trisomic pregnancies can be identified. When maternal serum free-β human chorionic gonadotrophin (β-hCG) and pregnancy-associated plasma protein-A (PAPP-A) at 11–14 weeks are also taken into account, the detection rate of chromosomal defects is about 90%. Increased NT can also identify a high proportion of other chromosomal abnormalities and is associated with major defects of the heart and great arteries, and a wide range of skeletal dysplasias and genetic syndromes. In monochorionic twins, discordancy for increased NT is an early marker of twin-to-twin transfusion syndrome (TTTS). As with the introduction of any new technology into routine clinical practice, it is essential that those undertaking the 11–14-week scan are adequately trained and their results are subjected to rigorous audit. Copyright © 2002 John Wiley & Sons, Ltd.     

Tetrasomy 12p—unusual presentation in CVS

CVS direct preparations usually achieve limited resolution and are better at detecting numerical rather than structural abnormalities. A CVS direct preparation analyzed using G-banding revealed a 47,XY,+G karyotype in 5 of 11 cells and was reported as mosaic for trisomy 21. Subsequent analysis of the CVS culture found only normal male cells. Amniocentesis revealed both normal male cells and cells with an extra F-group chromosome. Fluorescence in situ hybridization (FISH) identified this chromosome to be an isochromosome from the short arm of chromosome 12 [i(12)(p10)]. The amniocyte karyotype was reported as 47,XY,+i(12)(p10)[12]/46,XY[8].ish i(12)(p10)(wcp12+), which is associated with Pallister–Killian syndrome. Reexamination of the CVS direct preparation by FISH with a chromosome 12 centromere probe confirmed the karyotype of this tissue to be 47,XY,+mar[5]/46,XY[6].nuc ish 12cen(D12Z3 × 3)/12cen(D12Z3 × 2). Thus, multiple studies, including amniocentesis and fluorescence in situ hybridization, may be required to fully and accurately evaluate abnormalities detected by CVS. This case also indicates that mosaicism for supernumerary isochromosomes may have a complex origin. Copyright © 2003 John Wiley & Sons, Ltd.     

First-trimester maternal serum human thyroid-stimulating hormone in chromosomally normal and Down syndrome pregnancies

Maternal serum human thyroid-stimulating hormone (TSH) levels were investigated in chromosomally normal and Down syndrome pregnancies to determine whether TSH can be used as a marker for Down syndrome in the first trimester. Measurements were conducted on stored serum samples collected from 23 Down syndrome pregnancies and 115 unaffected pregnancies before chorionic villus sampling (CVS), between 9 and 11 completed weeks of pregnancy. The samples were matched for gestational age, maternal age, maternal weight and duration of storage of the serum sample. Maternal TSH concentration was slightly decreased in Down syndrome pregnancies, with a median of 0.84 multiples of the median (MoM). Maternal serum human chorionic gonadotropin (hCG) concentration was slightly elevated in Down syndrome pregnancies, with a median of 1.03 MoM. Both differences were not significant applying matched rank analysis (p=0.50 for TSH and p=0.43 for hCG). The association between TSH and hCG in unaffected pregnancies was also measured. The Spearman correlation coefficient between TSH and hCG was −0.21 which was statistically significant (p=0.02, 95% confidence interval −0.38 to −0.03). However, it was concluded that TSH is not a useful marker for distinguishing Down syndrome-affected pregnancies from normal pregnancies in the first trimester. Copyright © 2001 John Wiley & Sons, Ltd.     

试论长江文化生态的主要特征

大自然孕育了万物,人类又在自然的基础上创造了文化。久远深厚、异彩纷呈的长江文化,正是得益于广阔的发展舞台、优越的生态环境条件。因此探讨长江文化系统与生态环境系统的耦合关系－文化生态,就具有十分重要的意义。着重论述了长江文化生态的主要特征：（1）整体性－－长江文化生态系统的各组成部分是彼此联系、相互作用的统一,它能反映整体的特征和活动方式,它孕育了长江多元文化。（2）开放性－－长江流域是一个庞大的、开放的外流水网系统,该系统不从外部输入物质、能量和信息,吸收并累积负熵流,维持其有序性。长江文化具有悠久的开放传统和宽广的心态。（3）动态性－长江文化生态系统的动态特征,既有周期性变化也有非周期性变化。（4）人地相关性－长江文化生态民是人地关系相互作用的统一体,回顾长江文化的发展史,人与自然关系经历了“强烈依赖－－被动顺序－－主动征服－－相互和谐”几个阶段。     

Seeds and rights: new approaches to post-war agricultural rehabilitation in Sierra Leone

Based on preliminary findings of ongoing 'action research' in the war zone in central Sierra Leone, this paper shows how more equitable seed distribution could contribute to fostering a culture of human rights as well as to agricultural rehabilitation. Assessment of seeds-and-toosl programmes in 19 villages found that aid agency targeting and distribution modalities channelled inputs through village committees which denied assistance to intended beneficiary groups. Such distribution inequalities constitute violations of fundamental human rights, exacerbate grievance and division and maintain the threat of social disorder. The benefits and disadvantages of an alternative, more inclusive, rights-based approach to seed distribution are discussed, and preliminary results from the pilot phase of CARE's Rights-based Approach to Food Security Project are presented. Under this project, village-level peace and rights days are held to allow villagers to debate the vulnerabilities that facilitated the war and to elaborate on local notions of human rights. In symbolising new beginnings, seed can be seen as a useful medium through which to debate a more inclusive--and ultimately less vulnerable--society.     

In and Of the World? Christian Theological Anthropology and Environmental Ethics

Mainstream currents within Christianity havelong insisted that humans, among all creatures, areneither fully identified with their physical bodiesnor fully at home on earth. This essay outlines theparticular characteristics of Christian notions ofhuman nature and the implications of this separationfor environmental ethics. It then examines recentefforts to correct some damaging aspects oftraditional Christian understandings of humanity'splace in nature, especially the notions of physicalembodiment and human embeddedment in earth. Theprimary goal of the essay is not to offer acomprehensive evaluation of Christian thinking aboutnature but rather to identify theological anthropologyas a crucial dimension of, and problem for, Christianenvironmental ethics.