X线和CT对原发支气管癌的诊断价值

本文利用Ｘ线、ＣＴ扫描技术，对原发支气管瘤的各种组织类型在Ｘ线及ＣＴ中的表现进行了观察，分析了其位置、大小、边缘、钙化、空洞和转移情况，阐明了胸部ＣＴ是肺癌时诊断肺门和纵隔侵犯的更佳方法，较Ｘ线有很大优越性。Ｘ线和ＣＴ相结合对原发支气管癌的定性诊断具有重要价值。     

Modern and post-modern cities and ethnic residential segregation: Is Los Angeles different?

Dear and others associated with the ‘Los Angeles School of Urbanism’ have presented a series of challenging ideas regarding changes in urban form as a consequence of the shift from modernism to post-modernism. Some of those challenges relate to a city’s ethnic diversity and residential segregation, with Los Angeles presented as a paradigm exemplar of an emerging new urban form. This paper evaluates the arguments that Los Angeles in particular, and Californian metropolitan areas more generally, differ from metropolitan areas elsewhere in the United States in the nature of ethnic residential segregation there. Regression analyses provide little support for the argument, but graphical analyses show that although Los Angeles does not differ from the general, US-wide trends, its almost unique nature in terms of its ethnic diversity means that it clearly stands out as a place with a different pattern shared by very few others.     

Short Note: On the Relativistic Doppler Effect for Precise Velocity Determination using GPS

The Doppler effect is the apparent shift in frequency of an electromagnetic signal that is received by an observer moving relative to the source of the signal. The Doppler frequency shift relates directly to the relative speed between the receiver and the transmitter, and has thus been widely used in velocity determination. A GPS receiver-satellite pair is in the Earth’s gravity field and GPS signals travel at the speed of light, hence both Einstein’s special and general relativity theories apply. This paper establishes the relationship between a Doppler shift and a user’s ground velocity by taking both the special and general relativistic effects into consideration. A unified Doppler shift model is developed, which accommodates both the classical Doppler effect and the relativistic Doppler effect under special and general relativities. By identifying the relativistic correction terms in the model, a highly accurate GPS Doppler shift observation equation is presented. It is demonstrated that in the GPS “frequency” or “velocity” domain, the relativistic effect from satellite motion changes the receiver-satellite line-of-sight direction, and the measured Doppler shift has correction terms due to the relativistic effects of the receiver potential difference from the geoid, the orbit eccentricity, and the rotation of the Earth.     

Differential developmental toxicity of naphthoic acid isomers in medaka (Oryzias latipes) embryos

Polycyclic aromatic hydrocarbons (PAHs) are widespread persistent pollutants that readily undergo biotic and abiotic conversion to numerous transformation products in rivers, lakes and estuarine sediments. Here we characterize the developmental toxicity of four PAH transformation products each structural isomers of hydroxynaphthoic acid: 1H2NA, 2H1NA, 2H3NA, and 6H2NA. Medaka fish (Oryzias latipes) embryos and eleutheroembryos were used to determine toxicity. A 96-well micro-plate format was used to establish a robust, statistically significant platform for assessment of early life stages. Individual naphthoic acid isomers demonstrated a rank order of toxicity with 1H2NA>2H1NA>2H3NA>6H2NA being more toxic. Abnormalities of circulatory system were most pronounced including pericardial edema and tube heart. To determine if HNA isomers were AhR ligands, spatial-temporal expression and activity of CYP1A was measured via in vivo EROD assessments. qPCR measurement of CYP1A induction proved different between isomers dosed at respective concentrations affecting 50% of exposed individuals (EC50s). In vitro, all ANH isomers transactivated mouse AhR using a medaka CYP1A promoter specific reporter assay. Circulatory abnormalities followed P450 induction and response was consistent with PAH toxicity. A 96-well micro-plates proved suitable as exposure chambers and provided statistically sound evaluations as well as efficient toxicity screens. Our results demonstrate the use of medaka embryos for toxicity analysis thereby achieving REACH objectives for the reduction of adult animal testing in toxicity evaluations.     

A Comparison Between GEBCO Sheet 5.17 and the International Bathymetric Chart of the Arctic Ocean (IBCAO) Version 1.0

In 1979, the General Bathymetric Chart of the Oceans (GEBCO) published Sheet 5.17 in the Fifth Edition of its series of global bathymetric maps. Sheet 5.17 covered the northern polar region above 64° N, and was for long the authoritative portrayal of Arctic bathymetry. The GEBCO compilation team had access to an extremely sparse sounding database from the central Arctic Ocean, due to the difficulty of mapping in this permanently ice covered region. In the past decade, there has been a substantial increase in the database of central Arctic Ocean bathymetry, due to the declassification of sounding data collected by US and British Navy nuclear submarines, and to the capability of modern icebreakers to measure ocean depths in heavy ice conditions. From these data sets, evidence has mounted to indicate that many of the smaller (and some larger) bathymetric features of Sheet 5.17 were poorly or wrongly defined. Within the framework of the project to construct the International Bathymetric Chart of the Arctic Ocean (IBCAO), all available historic and modern data sets were compiled to create a digital bathymetric model. In this paper, we compare both generally and in detail the contents of GEBCO Sheet 5.17 and version 1.0 of IBCAO, two bathymetric portrayals that were created more than 20 years apart. The results should be helpful in the analysis and assessment of previously published studies that were based on GEBCO Sheet 5.17. Ron Macnab: Retired.     

Constituency election campaigning under the alternative vote: the New South Wales Legislative Assembly election 1995

Summary Most studies of the impact of local campaigning on the geography of election results in single-member constituency electoral systems have been conducted in countries where the 'first-past-the-post' system is employed. Australia uses the 'alternative vote' (AV) system for elections to the federal and some state Lower Houses, with parties competing for both first- and lower-preference votes. This paper analyses the relationship between spending and success in the contests for both types of votes at the 1995 New South Wales State Legislative Assembly election, with significant findings: the more intense a party's campaign, ceteris paribus, the more first-preference votes it obtained and the more lower-preference votess when these were reallocated. The AV system was recommended for adoption in the UK by a government-commissioned report in 1998, and the paper draws some implications for the UK situation.     

局部桩筏基础的设计与施工

以加拿大多伦多市某工程为例,介绍了在复杂地质条件下采用局部桩筏基础(PPRF)的设计及施工问题;探讨了设计PPRF的决定性因素;在保持PPRF设计的完整性前提下,提出了单位沉降量的准则,并用于筏板和桩的设计;计算了PPRF的滑移及转动;最后,采用有效方法对该工程采用的局部桩筏基础进行了计算分析.结果表明,PPRF的设计主要取决于侧向土压力、分布不均的建筑荷载以及地基土的非均匀承载力,工程桩应主要布置在沉降较大的区域,即位于筏板基础承受高压力而土体承载力较低的西北部.探讨局部桩筏基础的设计与施工为该类型工程的基础设计提供了一个新的解决途径.     

Decade time-scale modulation of low-mass X-ray binaries

Regular observations by the All-Sky Monitor aboard the Rossi X-ray Timing Explorer satellite have yielded well-sampled light curves with a time baseline of over 10 years. We find that up to eight of the 16 brightest persistent low-mass X-ray binaries (LMXBs) show significant, possible sinusoidal, variations with periods of the order of 10 years. We speculate on its possible origin and prevalence in the population of LMXBs, and we find the presence of a third object in the system, or long-period variability intrinsic to the donor star, as being attractive origins for the X-ray flux modulation we detect. For some of the objects in which we do not detect a signal, there is substantial short-term variation which may hide modest modulation on long time-scales. Decade time-scale modulations may thus be even more common.