Acardiac anomaly: current issues in prenatal assessment and treatment

Acardiac anomaly is a rare condition affecting monochorionic multiple pregnancies. We review this condition with emphasis on its prenatal diagnostic features and treatment options. Due to the parasitic hemodynamic dependence of the acardiac twin on the pump twin, it is important to monitor the pump twin for signs of decompensation and, if indicated, intervene by interrupting vascular supply to the acardiac twin. The goal of treatment is to maximize the pump-twin's chance of survival. To assist with the decision of when to treat, we suggest a new classification system based on prognostic factors, specifically the size and growth of the acardiac twin and the cardiovascular condition of the pump twin. When the acardiac twin is small and no signs of cardiovascular impairment in the pump twin are present, we suggest serial ultrasound surveillance to detect any worsening of the condition. In cases with a large acardiac twin or rapid growth of the acardiac mass, we recommend prompt intervention. Once treatment is indicated, the intrafetal approach to interrupt the vascular supply to the acardiac twin appears to be superior to cord occlusion techniques as it is simpler, safer and more effective. The first line of treatment, if available, should be ultrasound-guided laser coagulation or radiofrequency ablation of the intrafetal vessels. Copyright © 2005 John Wiley & Sons, Ltd.     

基于外部性的中小企业集群可持续竞争力内在机制研究

理论界对企业集群竞争力的解释与研究焦点．主要集中于对集群的积极效应的论证，基于负外部性的中小企业集群可持续性竞争力是一个尚未引起重视的研究领域。本文借鉴有关集群竞争力理论，提出了外部性是中小企业集群可持续竞争力内在源泉的观点。从外部性角度对中小企业集群可持续竞争力的内在机理进行挖掘。对中小企业集群外部性的主要形式及其效应进行了分析。本文还根据基于外部性的中小企业集群可持续竞争力产生机理模型，由集群的负外部性（成本）、正外部性（收益）曲线变化出发，研讨外部性、集群生命周期与集群竞争力变动的关系。提出了旨在提升中小企业集群可持续竞争力的“负外部性”规避对策。     

Could we remain simply applying discount rate to evaluate the life quality of our future generations?

When we try to estimate future environmental costs resulting from our current economic activities,we usually calculate the present value of the consequences for our future generations by utilizing a discount rate as a standard economic procedure.The popularity of this procedure is solely supported by its simplicity which assumes:(1)a perfect financial market over even 100 years,and(2)existence of a stable time preference between two consecutive periods for an individual consumer.An apparent deficiency of this approach is that the present value of life quality of future generations varies to a large extent along an arbitrarily chosen discount rate.As a matter of fact,the discount rate,which could reflect the time preference as2%or 5%,matters when we predict current strategies of environmental protection for future generations.Simply applying a discount rate to evaluate the quality of our future generation,without clarifying the actual production mechanism behind this,is almost to the same as ignoring the fact that all of the goods are produced through an actual production process and that environmental degradation reduces the efficiency of that process.The greatest concern for our future generations should not be given by an assumed discount rate,since the discount rate itself is determined by financial market conditions at certain points in time.     

基于场动力理论的建筑工人人格特质、情绪与不安全行为关系研究*

为深入探讨建筑工人人格特质、情绪与不安全行为之间的作用关系,提高建筑工人安全认知能力,以293名一线建筑工人为调查对象,基于场动力理论,构建人格特质和情绪对不安全行为影响机制的理论模型,实证检验人格特质和情绪对不安全行为的预测作用以及情绪调节效应。研究结果表明:外倾性、神经质、开放性3种人格正向预测不安全行为显著;正负性情绪对不安全行为水平具有显著影响,正性情绪在外倾性-不安全行为和神经质-不安全行为间具有显著调节效应,负性情绪在责任心-不安全行为和开放性-不安全行为间具有显著调节效应。研究结果可为建筑施工企业根据工人个性化心理特征,溯源工人自身安全问题,为后续开展分类干预管理和矫正不安全行为提供理论支持。     

Biosorption effects of copper ions on Candida utilis under negative pressure cavitation

Under the optimal condition of copper ions adsorption on yeast,we found some different effects among static adsorption, shaking adsorption and negative pressure cavitation adsorption, and the methods of yeast with different pretreatments also affect adsorption of copper ions. At the same time, the change of intercellular pH before and after adsorption of copper with BCECF was studied. The copper distribution was located by using PhenGreen （dipotassium salt and diacetate）, and the surface of yeast was observed by an atomic force microscope. The results showed that negative pressure cavitation can improve bioadsorption capacity of copper ions on yeast. However, the yeasts＇ pretreatment has a higher effect on bioadsorption. It indicates that heavy metal bioadsorption on yeast has much relation with its cellular molecule basis. With the adsorping, the intercellular pH of yeast increased gradually and changed from acidity to alkalescence. These results may suggest that negative pressure cavitation can compel heavy metals to transfer from the cell surface into inside cell and make the surface of yeast coarse.     

Delineating high-density areas in spatial Poisson fields from strip-transect sampling using indicator geostatistics: application to unexploded ordnance removal

An approach for delineating high anomaly density areas within a mixture of two or more spatial Poisson fields based on limited sample data collected along strip transects was developed. All sampled anomalies were transformed to anomaly count data and indicator kriging was used to estimate the probability of exceeding a threshold value derived from the cdf of the background homogeneous Poisson field. The threshold value was determined so that the delineation of high-density areas was optimized. Additionally, a low-pass filter was applied to the transect data to enhance such segmentation. Example calculations were completed using a controlled military model site, in which accurate delineation of clusters of unexploded ordnance (UXO) was required for site cleanup.     

粪尿分集全方位负压排臭生态卫生旱厕应用实例

介绍了粪尿分集生态卫生旱厕的特点及应用效果，该厕能节约和保护水资源，排泄物可再次利用，能形成可持续的完整的生态系统。具有较好的发展前景。     

Disastrous Abrupt Climate Events of Environment Change in Beijing in Recent 15,000 Years

Atpresent,theworldclimaticandenvironmentalchangesfromregionstoglobalextentatvarioustimescaleswillallbeinfluencedbyphysical,chemicalandbiologicalinteraction,someofthesechangesarerecordedinmarine,terrestrial,glacialandbiologicalenvironment,thereby,recon-structtemporallyandspatiallysignificanteventspastenvironmentalandecologicalconditions.In198o'sglobalclimatechangehasbeenwidelypaidattentiontointernationalization,aseriesofresearchplansincludingIGBPhasbeensetupandPAGES,BHAC,GCTEareimportantc…     

彝良5．7级地震前钻孔应变观测到的前兆异常

使用滇黔地区钻孔应变观测台站的资料,对2012年9月7日彝良Ms5．7地震前异常现象进行分析,结果表明,震前昭通、贵阳台钻孔应变出现长趋势等异常,其他台站在震前几小时到5天出现曲线异常波动、固体潮变形等异常现象。