西南地区全新世气候变化概述

本文较为系统地分析了西南地区石笋、泥炭和湖泊沉积物等自然记录恢复古气候的其本原理,概述了西南地区全新世(近万年来)气候变化研究的主要进展。鉴于西南地区古气候研究的现状,未来应着重加强三个方面的研究:1)加强石笋、泥炭和湖泊沉积物等代用指标记录气候变化的机理研究,建立更为有效的古气候定量/半定量重建方法;2)加强高分辨率、多指标的综合对比研究,揭示重大气候变化事件(如8.2 ka事件4、.2 ka事件和小冰期等)的性质及其对西南地区生态环境的影响;3)加强不同区域气候变化的对比研究,为揭示气候变化驱动力和合理预测西南未来可能出现的气候变化提供科学基础。     

Estimating the extinction date of the thylacine with mixed certainty data

The thylacine (Thylacinus cynocephalus), one of Australia's most characteristic megafauna, was the largest marsupial carnivore until hunting, and potentially disease, drove it to extinction in 1936. Although thylacines were restricted to Tasmania for 2 millennia prior to their extinction, recent so‐called plausible sightings on the Cape York Peninsula in northern Queensland have emerged, leading some to speculate the species may have persisted undetected. We compiled a data set that included physical evidence, expert‐validated sightings, and unconfirmed sightings up to the present day and implemented a range of extinction models (focusing on a Bayesian approach that incorporates all 3 types of data by modeling valid and invalid sightings as independent processes) to evaluate the likelihood of the thylacine's persistence. Although the last captive individual died in September 1936, our results suggested that the most likely extinction date would be 1940. Our other extinction models estimated the thylacine's extinction date between 1936 and 1943, and the most optimistic scenario indicated that the species did not persist beyond 1956. The search for the thylacine, much like similar efforts to rediscover other recently extinct charismatic taxa, is likely to be fruitless, especially given that persistence on Tasmania would have been no guarantee the species could reappear in regions that had been unoccupied for millennia. The search for the thylacine may become a rallying point for conservation and wildlife biology and could indirectly help fund and support critical research in understudied areas such as Cape York. However, our results suggest that attempts to rediscover the thylacine will be unsuccessful and that the continued survival of the thylacine is entirely implausible based on most current mathematical theories of extinction.     

大倾角煤层开采覆岩破断机制研究

为了探究大倾角煤层开采覆岩变形、失稳、破断的演化特征,结合潘二矿1212(3)工作面地质与工程条件,采用数值模拟、物理模拟、理论分析相结合的方法,分析了大倾角煤层开采覆岩变形破坏规律,探讨了巨厚砂岩直覆和无坚硬岩层2种条件下大倾角煤层开采顶板破断失稳形式。研究结果表明:受倾角影响直接顶冒落、滑移,充填下部采空区,基本顶中上部挠度最大而发生断裂,破断裂纹逐渐向基本顶两侧及相邻岩层演化;大倾角煤层倾向岩层间的联动时序性破断是形成非对称拱形承载结构的主因;预裂爆破巨厚砂岩顶板、充填开采软弱岩层工作面可促使关键块体组成的拱形承载结构形成,保证大倾角工作面安全回采。     

大连台地磁数字记录与模拟记录的对比分析

对正在运行的大连台地磁数字记录和模拟记录,从地磁相对记录的三种变化磁场的类型进行了逐一对比分析,结果表明,虽然数字记录的整体方面明显优于模拟记录,但二者又各有其特点,数字记录代替模拟记录应该还有一段过渡的过程。     

Prenatal and presymptomatic diagnosis of the marfan syndrome using fluorescence pcr and an automated sequencer

The Marfan syndrome (MFS) is a heritable connective tissue disorder characterized by skeletal, ocular, and cardiovascular abnormalities. Defects in fibrillin, an elastin-associated microfibrillar protein, are now known to cause MFS. Since the discovery of fibrillin as the gene responsible for MFS, requests for prenatal and presymptomatic diagnosis have become common-place. Here we report the use of the polymerase chain reaction (PCR), using fluorescence labelled primers and an automated sequencer, to establish linkage data for “molecular diagnosis”. The mistaken clinical diagnosis of MFS based on the appearance of a common cardiovascular manifestation, mitral valve prolapse, and a positive family history is also discussed.     

GENERALIZED LOW-FLOW FREQUENCY RELATIONSHIPS FOR UNGAGED SITES IN MASSACHUSETTS1

ABSTRACT: Regional hydrologic procedures such as generalized least squares regression and streamflow record augmentation have been advocated for obtaining estimates of both flood-flow and low-flow statistics at ungaged sites. While such procedures are extremely useful in regional flood-flow studies, no evaluation of their merit in regional low-flow estimation has been made using actual streamflow data. This study develops generalized regional regression equations for estimating the d-day, T-year low-flow discharge, Q_{d, t}, at ungaged sites in Massachusetts where d = 3, 7, 14, and 30 days. A two-parameter lognormal distribution is fit to sequences of annual minimum d-day low-flows and the estimated parameters of the lognormal distribution are then related to two drainage basin characteristics: drainage area and relief. The resulting models are general, simple to use, and about as precise as most previous models that only provide estimates of a single statistic such as Q_7,10. Comparisons are provided of the impact of using ordinary least squares regression, generalized least squares regression, and streamflow record augmentation procedures to fit regional low-flow frequency models in Massachusetts.     

长江三角洲空问运输联系与经济结构的时空演化特征分析

本文对长江三角洲1985-2000年各城市客、货运量进行了分析，总结出改革开放以来该区域空间运输联系的时空演化特征。长江三角洲客运量分布的廊道效应逐渐显著，货运量极化效应减弱。空间运输联系的时空演化反映了长江三角洲经济结构的推移特点。长江三角洲走廊经济突显，成为区域经济发展的有力带动轴；区域内浙东北经济崛起，成为与苏南地区相抗衡的经济板块；长江三角洲区域经济发展天平已出现向南倾斜的趋势。针对以上结论，本文认为长江三角洲地区应加快综台交通运输网络的建设，培育具有强大辐射效应的走廊经济，推动省、市之间协调合作与共同发展。     

北京市生产性土地的部门关联效应分析

本文基于生态足迹的投入产出模型,利用改进的HEM方法和北京市2007年投入产出表及相关数据,计算生产性土地的部门关联效应指标,对北京市9部门块土地资源关联效应进行了分析.研究结果表明:土地资源纵向总效应超过直接消耗的部门块主要由制造业、建筑业和服务业等部门构成;采选业部门块有更大的土地资源转让潜力;其他部门块都要从本部门块以外获取土地资源,导致各部门块的外部后向关联及外部前向关联都很大.本文认为:生产性土地的关联效应实际上是经济系统部门间土地资源需求的转移,最终需求总量不变,其结构调整就不会对土地资源总量产生影响;改进的HEM方法结合生态足迹最终需求,分析直接土地资源消耗数量,分解影响部门土地资源的组成因素,可以更直接、明确地量化部门间以及部门内部土地资源的关联关系;如果能够以实物型投入产出表代替货币型投入产出表,可以更加科学地反映经济系统中各产业部门土地资源的关联特性.