冷战后的美国对外政策

本文是根据结构现实主义理论大师肯尼斯·沃尔兹今年5月22日在北大的演讲节录而成。演讲中80高龄的沃尔兹从均势理论出发,以一战以来的国际政治结构演变为例,批驳了自由主义、制度主义等对美国外交政策演变的解释力,进而解释了美国冷战后外交政策变化的根本原因在于"一个简单的事件--强权从两个变为一个"。     

析俄罗斯煤炭运输的发展前景

能源供应的可靠性和战略稳定性要求俄罗斯在能源领域必须实现燃料—能源资源的部门结构和分布多元化。煤炭运输未来发展的预测是根据“2 0 2 0年前俄罗斯的能源战略”制定的 ,该战略确定了燃料由目前占绝对优势的碳氢化合物 (石油和天然气 )向煤炭、核能和再生材料过渡的进程。同时 ,能源战略的一些指标应该考虑到经济和能源中长期发展计划的可行性和实现性。建立国家未来的起支撑作用的运输网的首要任务 ,是修筑北西伯利亚铁路线     

Death by chainsaw: fatal kickback injuries to the neck

Each year over 3 million new chainsaws are sold in the United States. The operation of these newer saws combined with the millions of older chainsaws in circulation results in over 28,000 chainsaw-related injures annually. The majority of the injuries involve the hands and lower extremities with less than 10% involving injuries to the head and neck regions. Deaths while operating a chainsaw are extremely rare. The most common hazards associated with chainsaws are injuries caused by kickback, pushback, and pull-in. Kickback is the most common and poses the greatest hazard. Kickback occurs when the rotating chain is stopped suddenly by contact with a more solid area throwing the saw rapidly backward toward the operator. The cause of most injuries can be traced to improper use of the saw or poor judgment on part of the operator. We present two fatal chainsaw deaths; one with an older style saw, and the other with a modern type. In both cases the victims died from fatal injuries received to the neck region from a chainsaw kickback. The first case involved a 49-year-old white male operating an older style chainsaw with limited safety features. The second case involved a 38-year old white male who was operating a newer model chainsaw equipped with a low kickback chain in an unsafe manner.     

Medicolegal aspects of witnessed suicide due to gunshot to the head. II. Legal medicine aspects and examination of the firing hand

The second part of the paper on suicides by gunshots to the head in the presence of witnesses focuses on relevant morphological autopsy findings such as entrance site, signs of close range or contact shots, bullet path etc. and also discusses selected aspects of ascertaining gunshot residues. For the identification of the shooter an integral medicolegal assessment of all the facts including the investigation results and the autopsy findings is essential. However, the morphological findings alone do not allow safe diagnosis, as for example in a homicide the temporal region, which was affected in all our cases, may have been deliberately chosen by the perpetrator as a localization typical of suicide. Thus methods to ascertain gunshot residues on the firing hand (by means of adhesive films and the polyvinyl-alcohol collection method--PVAL) are of great practical importance. In seven cases adhesive films and/or the polyvinyl-alcohol collection method were used. In one case the gunshot residues (GSR) were analysed by means of tape lifts and subsequent scanning electron microscopy (SEM). It was found that especially the combined application of topographical (adhesive tape/PVAL) and cumulative (SEM) methods allowed for the doubtless identification of the shooter, thus usually confirming the suicide. By the example of one case it is demonstrated that without the immediate collection of evidence at the scene objective reconstruction of the event becomes impossible. On the basis of the reported cases recommendations are finally given for a differentiated approach in the medicolegal evaluation of alleged witnessed suicide by gunshot (to the head).     

Postmortem citalopram concentrations: alone or along with other compounds

Citalopram, an antidepressant whose use has become more widespread in Spain in recent years participates directly and indirectly in the lethal mechanism in voluntary and involuntary poisonings. There were 30 cases of autopsies in the Madrid region where citalopram and other psychoactive substances (psychotropic drugs, alcohol, opiates) were detected in the corpses. The postmortem citalopram levels in relation to the manner and mechanism of death were evaluated, and a significant difference between the toxic and nontoxic cases (p < 0.01) was found. We studied the citalopram blood levels alone and along with other psychoactive products, and these cases were then further divided into those where the compounds were at deadly levels and those which were not. We found a range of citalopram levels between 0.37 and 0.83 microg/mL in which some cases were associated with citalopram toxicity and others were not. Citalopram blood levels of less than 0.35 microg/mL did not lead to fatal poisoning when it was the sole substance detected.     

Y-chromosome STR system, Y-PLEX 12, for forensic casework: development and validation

The Y-PLEX 12 system, developed for use in human identification, enables simultaneous amplification of eleven polymorphic short tandem repeat (STR) loci, namely DYS392, DYS390, DYS385 a/b, DYS393, DYS389I, DYS391, DYS389II, DYS 19, DYS439 and DYS438, residing on the Y chromosome and Amelogenin. Amelogenin provides results for gender identification and serves as internal control for PCR. The validation studies were performed according to the DNA Advisory Board's (DAB) Quality Assurance Standards. The minimal sensitivity of the Y-PLEX 12 system was 0.1 ng of male DNA. The mean stutter values ranged between 3.76-15.72%. A full male profile was observed in mixture samples containing 0.5 ng of male DNA and up to 400 ng of female DNA. Amelogenin did not adversely affect the amplification of Y-STRs in mixture samples containing male and female DNA. The primers for the Y-STR loci present in Y-PLEX 12 are specific for human DNA and some higher primates. None of the primate samples tested provided a complete profile at all 11 Y-STR loci amplified with the Y-PLEX 12 system. Y-PLEX 12 is a sensitive, valid, reliable, and robust multiplex system for forensic analysis, and it can be used in human forensic and male lineage identification cases.     

Enhanced kinship analysis and STR-based DNA typing for human identification in mass fatality incidents: the Swissair flight 111 disaster

A bioinformatic tool was developed to assist with the victim identification initiative that followed the Swissair Flight 111 disaster. Making use of short tandem repeat (STR) DNA typing data generated with AmpFlSTR Profiler Plus (PP) and AmpFlSTR COfiler(CO) kits, the software systematically compared each available STR genotype with every other genotype. The matching algorithm was based on the search for: (i) direct matches to genotypes derived from personal effects; and (ii) potential kinship associations between victims and next-of-kin, as measured by allele sharing at individual loci. The software greatly assisted parentage analysis by enabling kinship evaluation in situations where complete parentage trios were unavailable and, in some situations, with distantly related relatives. Exclusion of fortuitous kinship associations (FKA) was made possible through the recovery at the disaster site of at least one remains for every sought-after victim, and was incorporated into the kinship software. The data from the 13 combined STR loci produced 6 and 23 times fewer FKAs when compared with PP alone and AmpFlSTR Profiler (PR) alone, respectively. Identification leads or confirmations of identification were obtained for 218 victims for which DNA reference samples (personal effects and kin) had been submitted. Confirmation of an inferred kinship association was sought through frequency and likelihood calculations, as well as corroborative data from other identification modalities. The use of a simple, yet powerful, automated genotype comparison approach and the use of megaplexes with high power of discrimination (PD) values extended considerably the identification capabilities in the case of the Swissair disaster. The DNA typing identification modality proved to be a valuable component of the large arsenal of identification tools deployed in the aftermath of this disaster.     

Systematic analysis of stutter percentages and allele peak height and peak area ratios at heterozygous STR loci for forensic casework and database samples

To assist the interpretation of STR DNA typing results from forensic casework samples containing mixtures, the range of heterozygous allele peak height and peak area ratios (HR) and stutter percentages (stutter %) for the loci comprised in the AmpFlSTR Profiler Plus (PP) kit were assessed on 468 database and 275 casework single source samples. Stutter % medians were similar for database and casework samples, ranging from 2% to 7%. The upper limit of the stutter value range was 16%, calculated as median +3 SD, although lower locus-specific values could be used. HR medians were 93 +/- 6.5% for database samples, 88 +/- 12% for casework samples. For casework samples, the maximum signal imbalance noted was 52%, calculated as median -3 SD. No significant difference was observed between peak height and peak area calculated values. This study shows the importance of selecting the proper reference database for the establishment of HR threshold values.