Annama H chondrite—Mineralogy,physical properties,cosmic ray exposure,and parent body history

The fall of the Annama meteorite occurred early morning (local time) on April 19, 2014 on the Kola Peninsula (Russia). Based on mineralogy and physical properties, Annama is a typical H chondrite. It has a high Ar‐Ar age of 4.4 Ga. Its cosmic ray exposure history is atypical as it is not part of the large group of H chondrites with a prominent 7–8 Ma peak in the exposure age histograms. Instead, its exposure age is within uncertainty of a smaller peak at 30 ± 4 Ma. The results from short‐lived radionuclides are compatible with an atmospheric pre‐entry radius of 30–40 cm. However, based on noble gas and cosmogenic radionuclide data, Annama must have been part of a larger body (radius >65 cm) for a large part of its cosmic ray exposure history. The ¹⁰Be concentration indicates a recent (3–5 Ma) breakup which may be responsible for the Annama parent body size reduction to 30–35 cm pre‐entry radius.     

On atmospheric wave generation by the terminator

The dominant response of the terminator is found to be due to the change in thermospheric absorption of solar radiation, and leads to two types of atmospheric waves: (i) a ducted acoustic wave at altitudes below 100 km and (ii) a boundary wave concentrated along the mesopause.     

InSAR测量的初步研究长江三峡工程库首区

正在进行的长江三峡水利枢纽工程将建成世界上最大的人工水库,已有的研究表明, 高坝水库有可能诱发中强地震.合成孔径雷达干涉测量(InSAR)已成为测量地球表面变化极具潜力的技术.对欧洲遥感卫星ERS-1与ERS-2的SAR数据的初步分析表明:只要时间跨度不太长,在有植被覆盖、地形起伏较大的山区亦能获得较为理想的干涉图像.结合三峡地壳形变监测网络,利用InSAR技术完全有希望识别三峡工程蓄水过程的地表变形.     

Timeline analysis and wavelet multiscale analysis of the AKARI All-Sky Survey at 90 μm

We present a careful analysis of the point-source detection limit of the AKARI All-Sky Survey in the WIDE-S 90-μm band near the North Ecliptic Pole (NEP). Timeline analysis is used to detect IRAS ( Infrared Astronomy Satellite ) sources and then a conversion factor is derived to transform the peak timeline signal to the interpolated 90-μm flux of a source. Combined with a robust noise measurement, the point-source flux detection limit at signal-to-noise ratio  (S/N) > 5  for a single detector row is  1.1 ± 0.1 Jy  which corresponds to a point-source detection limit of the survey of ∼0.4 Jy.
Wavelet transform offers a multiscale representation of the Time Series Data ( tsd ). We calculate the continuous wavelet transform of the tsd and then search for significant wavelet coefficients considered as potential source detections. To discriminate real sources from spurious or moving objects, only sources with confirmation are selected. In our multiscale analysis, IRAS sources selected above 4σ can be identified as the only real sources at the Point Source Scales. We also investigate the correlation between the non- IRAS sources detected in timeline analysis and cirrus emission using wavelet transform and contour plots of wavelet power spectrum. It is shown that the non- IRAS sources are most likely to be caused by excessive noise over a large range of spatial scales rather than real extended structures such as cirrus clouds.     

On the dynamics of the jovian ionosphere and thermosphere.: IV. Ion-neutral coupling

We use the fully coupled, three-dimensional, global circulation Jovian Ionospheric Model (JIM) to calculate the coupling between ions in the jovian auroral ovals and the co-existing neutral atmosphere. The model shows that ions subject to drift motion around the auroral oval, as a result of the E×B coupling between a meridional, equatorward electric field and the jovian magnetic field, generate neutral winds in the planetary frame of reference. Unconstrained by the magnetic field, these neutral winds have a greater latitudinal extent than the corresponding ion drifts. Values of the coupling coefficient, k(h), are presented as a function of altitude and cross-auroral electric field strength, for different incoming electron fluxes and energies. The results show that, with ion velocities of several hundred metres per second to over 1 km s⁻¹, k(h) can attain values greater than 0.5 at the ion production peak. This parameter is key to calculating the effective conductivities required to model magnetosphere-ionosphere coupling correctly. The extent to which angular momentum (and therefore energy) is transported vertically in JIM is much more limited than earlier, one-dimensional, studies have predicted.     

QSO lensing magnification associated with galaxy groups

We simulated both the matter and light (galaxy) distributions in a wedge of the Universe and calculated the gravitational lensing magnification caused by the mass along the line-of-sight of galaxies and galaxy groups identified in sky surveys. A large volume redshift cone containing cold dark matter particles mimics the expected cosmological matter distribution in a flat universe with low matter density and a cosmological constant. We generate a mock galaxy catalogue from the matter distribution and identify thousands of galaxy groups in the luminous sky projection. We calculate the expected magnification around galaxies and galaxy groups and then the induced quasi-stellar object (QSO)–lens angular correlation due to magnification bias. This correlation is observable and can be used both to estimate the average mass of the lens population and to make cosmological inferences. We also use analytical calculations and various analyses to compare the observational results with theoretical expectations for the cross-correlation between faint QSOs from the 2dF Survey and nearby galaxies and groups from the Automated Plate Measurement and Sloan Digital Sky Survey Early Data Release. The observed QSO–lens anticorrelations are stronger than the predictions for the cosmological model used. This suggests that there could be unknown systematic errors in the observations and data reduction, or that the model used is not adequate. If the observed signal is assumed to be solely due to gravitational lensing, then the lensing is stronger than expected, due to more massive galactic structures or more efficient lensing than simulated.     

A comprehensive study of distribution laws for the fragments of Košice meteorite

In this study, we conduct a detailed analysis of the Ko?ice meteorite fall (February 28, 2010), to derive a reliable law describing the mass distribution among the recovered fragments. In total, 218 fragments of the Ko?ice meteorite, with a total mass of 11.285 kg, were analyzed. Bimodal Weibull, bimodal Grady, and bimodal lognormal distributions are found to be the most appropriate for describing the Ko?ice fragmentation process. Based on the assumption of bimodal lognormal, bimodal Grady, bimodal sequential, and bimodal Weibull fragmentation distributions, we suggest that, prior to further extensive fragmentation in the lower atmosphere, the Ko?ice meteoroid was initially represented by two independent pieces with cumulative residual masses of approximately 2 and 9 kg, respectively. The smaller piece produced about 2 kg of multiple lightweight meteorite fragments with the mean around 12 g. The larger one resulted in 9 kg of meteorite fragments, recovered on the ground, including the two heaviest pieces of 2.374 kg and 2.167 kg with the mean around 140 g. Based on our investigations, we conclude that two to three larger fragments of 500–1000 g each should exist, but were either not recovered or not reported by illegal meteorite hunters.     

2006年ESRI开发者研讨会随笔

ESRI的国际用户研讨会5月17-18日在California举行,James Fee在自己的BLOG中谈到了这次研讨会中几个非常好的Comments,并对ArcGIS家族体系中的一些新特性给予了描绘。Web ADF它毫无疑问该排第一位。仅从用户及开发人员在9.1中配置专业地图存在的困难来说,Web ADF(译者注:Appli-