Putative Meteoritic Craters in Río Cuarto (Central Argentina) Interpreted as Eolian Structures

Ten oblong aligned depressions in the Río Cuarto area (provincia de Córdoba, Argentina) were supposed to be the result of very-low-angle Holocene meteoroid impacts. However, we consider that authors that studied the structures did not demonstrated their extraterrestrial origin. We suggest that an eolian origin for the structures of Río Cuarto is more likely. Actually, these landforms integrate large systems of similar deflation/accumulation geoforms aligned according to predominant winds during different periods.     

Trends of urban air pollution in Zhengzhou City in 1996–2008

Urban air pollution is a commonly concerned environmental problem in the world.Identification of air quality trend using long-term monitoring data is helpful to understand the effectiveness of pollution control strategies.This study,using data from six monitoring stations in Zhengzhou City,analyzed the changing trend in concentrations of SO 2,NO x /NO 2 and TSP/PM 10 in 1996-2008,based on non-parametric Mann-Kendall test and Sen’s slope estimator,and evaluated the comprehensive air pollution level using Multi-Pollutant Index(MPI).It was found that the concentration of each pollutant exceeded obviously the World Health Organization(WHO) guideline value,but the changing trend varied:SO 2 and NO 2 were significantly increased mainly due to an increase in coal consumption and vehicle number,while NO x,TSP and PM 10 decreased.The air pollution was serious,and differed markedly among the three functional regions:it is the most severe in the Industrial and Residential Area(IRA),followed by the Transportation Hub and Business District(THBD),and then the High-tech,Cultural and Educational Area(HCEA).Different from NO 2 concentration that had a similar change trend/rate among the function regions,the change rate of PM 10 concentration differed spatially,decreased much more obviously in THBD than other two regions.For the whole city,the comprehensive air pollution level declined gradually,illustrating that the air quality in Zhengzhou was improved in the last decade.     

Five young star clusters in the outer region of the Small Magellanic Cloud

Colour–magnitude diagrams in the Washington system are presented for the first time for five star clusters projected on to the outer region of the Small Magellanic Cloud (SMC). The clusters are found to have ages in the range 0.1–1.0 Gyr, as derived from the fit of isochrones with   Z = 0.004  . This sample increases substantially the number of young clusters in the outer SMC – particularly in the south-east quadrant – with well-derived parameters. We combine our results with those for other clusters in the literature to derive as large and homogeneous a data base as possible (totalling 49 clusters) in order to study global effects. We find no conclusive evidence for a dispersion in the cluster ages and metallicities as a function of their distance from the galaxy centre, in the SMC outer region. L 114 and 115, although very distant, are very young clusters, lying in the bridge of the SMC and therefore most likely formed during the interaction which formed this feature. We also find very good agreement between the cluster age–metallicity relation (AMR) and the prediction from a bursting model from Pagel & Tautvaišienė with a burst that occurred 3 Gyr ago. Comparing the present cluster AMR with that derived by Harris & Zaritsky for field stars in the main body of the SMC, we find that field stars and clusters underwent similar chemical enrichment histories during approximately the last couple of Gyr, but their chemical evolution was clearly different between 4 and 10 Gyr ago.     

Monte‐Carlo simulation of a possible correlation between the estimated luminosity distances and internal extinctions of type Ia supernovae

This paper describes a Monte Carlo simulation of type Ia supernova data. It was shown earlier that the data of SNe Ia might contain a possible correlation between the estimated luminosity distances and internal extinctions. This correlation was shown by different statistical investigations of the data. In order to remove observational biases (for example the effect of the detection limit of the observing instrument) and to test the reality of the effect found earlier we developed a simple routine which simulates extinction values, redshifts and absolute magnitudes for Ia supernovae. We pointed out that the correlation found earlier in the real data between the internal extinction and luminosity distance does not occur in the simulated sample. Furthermore, it became obvious that the detection limit of the observing devices used in supernova projects does not affect the far end of the redshift‐luminosity distance relationship of Ia supernovae. This result strengthens the earlier conclusions of the authors that SN Ia supernovae alone do not support the existence of dark energy. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Perturbed Gylden Systems and Time-Dependent Delaunay-Like Transformations

We study the possibilities and limitations of the application of generalized Delaunay-like transformations (in the 6-dimensional phase space) and TR-like mappings (in the 8-dimensional, extended phase space) to perturbed two-body problems with a time-varying Keplerian parameter μ(t), that is, to Gylden-type systems. For the sake of theoretical completeness, both negative- and positive-energy motion (with nonstationary coupling parameter) are, in principle, considered. Our developments are intended to introduce canonical variables parallelling the classical ones of Delaunay and the Delaunay-Similar variables of Scheifele. This revised version was published online in August 2006 with corrections to the Cover Date.     

Morphological similarities between DBM and a microeconomic model of sprawl

We present a model that simulates the growth of a metropolitan area on a 2D lattice. The model is dynamic and based on microeconomics. Households show preferences for nearby open spaces and neighbourhood density. They compete on the land market. They travel along a road network to access the CBD. A planner ensures the connectedness and maintenance of the road network. The spatial pattern of houses, green spaces and road network self-organises, emerging from agents individualistic decisions. We perform several simulations and vary residential preferences. Our results show morphologies and transition phases that are similar to Dieletric Breakdown Models (DBM). Such similarities were observed earlier by other authors, but we show here that it can be deducted from the functioning of the land market and thus explicitly connected to urban economic theory.     

The environmental quality of the sewage discharge area of Qingdao Cove—A cladistic analysis

This study on the environmental quality of the Qingdao Cove intertidal zone sewage discharge area is based on data obtained from the December of 1989 and 1990 macrobenthos investigations there, and uses pollution indicator species and computer aided cladistic analysis to divide the area into a polluted area and a semipolluted area. The study showed the environmental quality in 1990 improved over that in 1989. Project supported by the National Natural Science Fonndation of China     

The geochemical and petrological characteristics of prenatal caldera volcano: a case of the newly formed small dacitic caldera,Hijiori, Northeast Japan

Evaluating the magma depth and its physical properties is critical to conduct a better geophysical assessment of magma chambers of caldera volcanoes that may potentially cause future volcanic hazards. To understand pre-eruptive conditions of a magma chamber before its first appearance at the surface, this paper describes the case of Hijiori caldera volcano in northeastern Japan, which emerged approximately 12,000 years ago at a place where no volcano ever existed. We estimated the depth, density, bulk modulus, vesicularity, crystal content, and bulk H\(_2\)O content of the magma chamber using petrographic interpretations, bulk and microchemical compositions, and thermodynamic calculations. The chemical mass balance calculations and thermodynamic modeling of the erupted magmas indicate that the upper portion of the Hijiori magmatic plumbing system was located at depths between 2 and 4 km, and had the following characteristics: (1) pre-eruptive temperature: about 780 \(^{\circ }\)C; (2) bulk magma composition: 66 ± 1.5 wt% SiO\(_{2}\); (3) bulk magmatic H\(_2\)O: approximately 2.5 wt%, and variable characteristics that depend on depth; (4) crystal content: \(\le\)57 vol%; (5) bulk modulus of magma: 0.1–0.8 GPa; (6) magma density: 1.8–2.3 g/cm³; and (7) amount of excess magmatic H\(_2\)O: 11–32 vol% or 48–81 mol%. The range of melt water contents found in quartz-hosted melt inclusions (2–9 wt%) suggests the range of depth phenocrysts growth to be wide (2\(\sim\)13 km). Our data suggest the presence of a vertically elongated magma chamber whose top is nearly solidified but highly vesiculated; this chamber has probably grown and re-mobilized by repeated injections of a small amount of hot dacitic magma originated from the depth.     

钻孔灌注混凝土摩擦桩的荷载传递和测试

在软弱地基和城市高层建筑物地基的工程处理中,钻孔灌注摩擦桩的应用有日益增多的趋势。本文结合其施工特征在理论上分析了灌注摩擦桩的承载机制和荷载传递性能,并以现场工程实例加以说明。同时,本文指出用实测法确定荷载传递规律时还存在着弹性模量、桩径变化等取值问题,须有待进一步研究。尽管如此,笔者认为用现场实测法确定荷载传递规律还是要比其它方法更接近于实际     

盆地地史模拟述评

论述了盆地地史模拟的一般研究方法，认为回剥法是现今重建盆地沉积史与构造史最精确的方法详细讨论了地坟实校正、不整合处理和构造沉隆分析等主要数学模型及其适用范围；并在介绍地史模拟研究历史和研究现状的基础上，指出了地史模拟的发展方向。