EXPECTATION-MAXIMIZATION ALGORITHM FOR REGRESSION,DECONVOLUTION AND SMOOTHING OF SHOT-NOISE LIMITED DATA

A simple algorithm for deconvolution and regression of shot-noise-limited data is illustrated in this paper.The algorithm is easily adapted to almost any model and converges to the global optimum.Multiple-component spectrum regression,spectrum deconvolution and smoothing examples are used to illustratethe algorithm.The algorithm and a method for determining uncertainties in the parameters based on theFisher information matrix are given and illustrated with three examples.An experimental example ofspectrograph grating order compensation of a diode array solar spectroradiometer is given to illustratethe use of this technique in environmental analysis.The major advantages of the EM algorithm are foundto be its stability,simplicity,conservation of data magnitude and guaranteed convergence.     

Periodic Variations of the Jet Flow Lorentz Factor in 3C 273

1 INTRODUCTIONThe quasar 3C 273 (z = 0.158) is one of the classical rwho sources showal apparellt superltalnal motion (Zensus et al. 1990, 1997). It has a large-scale jet (~ 20n of length, 3C273A)elliltting at radio, optical and X-ray bands. It has been suggested that its compel source(3C 273B) is a rmm-blazar, Undergoing strong and rapid Variations in ratio, optical-UV, X-rayand 7-my bands at various tab scales (from hours to years, Courvoisier et al. 1998, Tet al. 1999, Stevens et …     

Petrogenetic significance of rare-earth element behavior in the basement rocks of southern Obudu Plateau, Bamenda Massif, southeastern Nigeria

Rock samples representing various igneous and metamorphic rocks of southern Obudu Plateau were analyzed for rare-earth element ( REE ) behavior by ICP-MS. Results of the analyses indicate a range of REE abundances and distinctive patterns from highly fraetionated patterns with negative Eu anomalies in granitic rocks to relatively low abundances and less REE fractionated flat patterns with little Eu anomaly in some paragneisses, schists, enderbites and dolerites to unfractionated patterns with positive Eu anomalies in some paragneisses and charnockites. Over all, there are low to high ∑ REE contents with negative to positive Eu anomalies. The ratios of different parameters, especially La/Yb and Ce/Yb, show behaviors consistent with crustal to mantle derivation. The heterogeneity of REE abundances and REE patterns reflects mantle to crustal petrogenetic variations of different rock suites on the Plateau. The LREE content is higher than the HREE content in the highly differentiated rocks, as evidenced by their La/Yb,Ce/Yb and La/Sm ratios, which are normally higher in residual products than in primary melts. The dominantly intermediate nature of the source rock of the orthogneisses is suggested by the generally low ∑ REE. The granites enriched in LREE and depleted in HREE and some of the charnockites with negative Eu anomalies were probably formed by partial melting and crystallization.     

TIME EVOLUTION OF LOCAL SCOUR AT OBSTACLES PROTRUDING FROM CHANNEL SIDE WALLS

1 mnCnONLocal scour close to bridge piers and abUtInnts has long been a subect of concem for engineers, sinceit can We total or partial collapse of bridges. Until to the Present, local scour has been assessed, moshy,on the basis of resultS of labOratOry stodis. These sthes were cwhed out for steady flows lashng longenough as to gUarantee the develoPment of equlllbrium scour i.e., the develoPmen of scour holes whosedePth and 8haPe no lOnger significanti evolve with hme.In nta, such long l…     

对断层岩术语的建议

对于在高压条件下经历后期动力变质作用所形成的断层岩的传统术语,已由许多专家加以讨论.但是,对于地质的、工程的和其他有关的专业来说,需要一种普遍适用而且简单的术语体系,这种系统涉及到断层岩本身及其相关的构造术语.这里我们提出了这样一种术语体系,它以应变率与恢复率为纲,并且与沿着断层的脆性和韧性变形的产物联系起来.     

在钻孔条件下试验金刚石切削具

本文作者U．Deutsch先生系联邦德国克劳斯塔尔工业大学深钻和采油技术研究所博士研究生。今年6月应本刊编委会副主任委员、北京地质教育中心李世忠教授邀请来华讲学，介绍了联邦德国深孔水平钻进、岩石破碎研究和将在联邦德国实施14000m超深孔的技术准备等情况。并访问了勘探技术研究所、探矿工程研究所和长春地质学院等单位。作者应本刊编辑部邀请为纪念本刊创刊30周年而热心撰写此文。     

臭氧研究的过去、现在和将来

二十世纪七十年代,对臭氧的研究发展迅速,以新的见解表明了这种痕量气体对人类的重要性。在八十年代开始之际,回顾一下臭氧研究的早期工作,并且分析一下最近的发展情况,将有助于安排近期工作和长远计划。一、臭氧研究简史大约一百年前,Hanley发现臭氧能强烈地吸收紫外线,提出了这种气体具有能吸收阳光光谱中短于300毫微米部份的特性。Fafy和Buisson证实了这种意想不到的问题,并提出了测量高层大气中臭氧总含量的可行方法,开始了大气臭氧的研究,迄今已有六十多年了。     

阿拉伯海小暖池混合层盐度的年度变化

采用ECMWF的ORAS4盐度资料（1999—2009年）来研究阿拉伯海暖池区（ASMWP）混合层盐度的年际变化.基于ORAS4盐度的季节循环特征与观测资料高度一致,发现了ASMWP混合层盐度变化的异常高（低）盐度时期,即在2003、2005年的7—10月混合层盐度异常偏大,而2002年2—4月则有明显减弱.进一步研究发现,混合层盐度的强度和持续时间与ENSO和IOD有一定的关系,ASMWP混合层盐度异常在IOD负位向和ENSO负位相的时候偏高,反之亦然.最后,通过盐度收支分析发现,水平输运是导致ASMWP混合层盐度异常年际变化的主要因子.     

Biochemical biomarkers in adult female perch (Perca fluviatilis) in a chronically polluted gradient in the Stockholm recipient (Sweden)

A battery of biochemical biomarkers and the SigmaPCB concentration in adult female perch (Perca fluviatilis) verified an aquatic pollution gradient with the city of Stockholm (Sweden) as a point source of anthropogenic substances. The investigation included both an upstream gradient, 46 km westwards through Lake M?laren, and a downstream gradient, 84 km eastwards through the Stockholm archipelago. Besides the main gradient from Stockholm, there were strong indications of pollution coming from the Baltic Sea. The results indicated a severe pollution situation in central Stockholm, with poor health status of the perch, characterised by increased specific EROD activity in the liver, increased liver EROD somatic index, decreased AChE activity in the muscle, increased amount of DNA adducts in the liver, and a high concentration of biliary 1-pyrenol. In addition, laboratory exposure to common EROD inducers elicited an abnormal response, suggestive of chronic intoxication.