Meteor observations in Japan: new implications for a Taurid meteoroid swarm

Observational evidence is sought that the long-term (10⁴ yr) action of a mean motion resonance with Jupiter can produce structure in a meteoroid stream, concentrating meteoroids in a dense swarm. More specifically, predictions tabulated by Asher & Clube of enhanced meteor and fireball activity from a Taurid Complex swarm in the 7:2 resonance are compared with observational data collected in Japan over several decades. The swarm model was proposed for reasons independent of the observations analysed here, and these newly considered data are shown to be consistent with it. This allows increased confidence in the Taurid swarm theory, and more generally could mean that resonant trapping is a dynamical mechanism affecting a significant amount of meteoroidal material in the inner Solar system.     

Follow‐up observations of Comet 17P/Holmes after its extreme outburst in brightness end of October 2007

We present follow‐up observations of comet 17/P Holmes after its extreme outburst in brightness, which occurred end of October 2007. We obtained 58 V‐band images of the comet between October 2007 and February 2008, using the Cassegrain‐Teleskop‐Kamera (CTK) at the University Observatory Jena. We present precise astrometry of the comet, which yields its most recent Keplerian orbital elements. Furthermore, we show that the comet's coma expands quite linearly with a velocity of about 1650 km/s between October and December 2007. The photometric monitoring of comet 17/P Holmes shows that its photometric activity level decreased by about 5.9 mag within 105 days after its outburst (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Short-period Jupiter family comets after Stardust

The NASA Stardust mission has provided for laboratory study an extensive data set of cometary dust of known provenance (from comet 81P/Wild 2) yielding detailed insights into the composition of the comet. Combined with the results of data from other missions to short-period Jupiter family comets (JFC), this has greatly deepened the understanding of such objects. If depressions on the surface of comet 81P/Wild 2 are all taken as evidence of impact cratering, their number suggests a long occupancy in the outer region of the Solar System. The dust from comet 81P/Wild 2 has been shown to be heavily deficient in pre-Solar grains and rich in materials formed at high temperatures in the inner Solar System. Although it is too early to know if this is typical of JFC, it does argue for rapid and thorough mixing of materials in the disk on timescales related to comet formation, and may also suggest outward migration of small icy bodies after their formation. Thus, instead of providing mainly new knowledge of the pre-Solar materials expected to be rich in comets, Stardust and comet 81P/Wild 2 have instead focussed attention on large-scale transport processes during the critical period when cometary parent bodies were forming in the early Solar System.     

Features of a comet nucleus: The case of 103P/Hartley 2

In the paper two chosen features of the comet 103P/Hartley 2 are studied. The first one are ‘cometary geysers’ which have been recorded by the camera on Deep Impact spacecraft. The numerical calculations related with this phenomenon have been carried out for large number of values of probable cometary characteristics. Our calculations confirm the assumption what also has been observed by NASA's scientists that the jets of carbon dioxide from the geysers are able to lift large chunks of water ice from the comet. The second discussed feature of the comet 103P/Hartley 2 is the lack of impact holes on the surface of its nucleus. The expected rate of impact holes on the surface of the nucleus of 103P/Hartley 2 is discussed. These holes could be the product of impacts between this comet and other small bodies orbiting in the main asteroid belt. The probability of such impacts, the total number of expected perceptible holes and changes in the luminosity of the comet caused by collisions are examined. We conclude that indeed the number of visible holes on its surface should be negligible (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

副蝎蛉科化石（昆虫纲长翅目）在中国首次发现

报道了华夏三叠副蝎蛉Triasoparachorista huaxiaensis gen. et sp nov. (T2t)、吐孜沟准噶尔蝎蛉Junggarochorista tuzigouensis Hong. nom. nov. (J1b) 和1个新转移属——冀北直脉蝎蛉属Jibeiorthophlebia Hoing, 1983 (transl. nov.) (J2)及其2个种J. xiaofangzhangziensis Hong,1983 (transl. nov.)、J. internata Hong,1983 (transl. nov.) 在中国首次发现。根据它们的脉序特征,在分类上应当归于Parachoristidae Tillyard, 1937。这个科既具有二叠蝎蛉科(Permochoristidae) MP 带6支脉的特征,又有直脉蝎蛉科(Orthophlebiidae) Rs1至少带3支脉呈扇形排列的特征, 形成二叠蝎蛉科和直脉蝎蛉科之间的一种独特的过渡特征的中间类群,这个类群对它们之间的演变关系的研究有重要意义。副蝎蛉科化石在中国的发现很有意义：①填补了中国中三叠世、早侏罗世、中侏罗世副蝎蛉科的空白;②可以帮助我们追溯副蝎蛉科、直脉蝎蛉科和二叠蝎蛉科之间在不同地质背景中的演变关系;③关于中侏罗世燕辽生物群及其有关问题,笔者曾先后指出,燕辽生物群(Yanliao Biota)（J2）和热河生物群（K1）均起源于华北古陆（North China Paleocontinent）,燕辽地区（覆盖了新增加的内蒙古宁城地区）是它们的起源中心,尔后向外扩散与迁移,并向北覆盖到蒙古东部、俄罗斯外贝加尔等地区,形成东亚古陆（Eastern Asian Paleocontinent）中一个广阔的燕辽生物群和热河生物群的区系;④讨论了宁城地区地层层位的归属问题。     

精密单点定位估计GPS卫星的P1-C1码偏差及稳定性分析

给出了利用精密单点定位（PPP）技术估计GPS卫星P1-C1码偏差的数学模型,并以BRUS、GODE、SHAO和NIST四个跟踪站2010年10月份一个月的观测数据为例,采用PPP方法计算了所有GPS卫星的P1-C1码偏差,并与欧洲定轨中心提供的P1-C1码偏差进行了比较,结果表明：四个站估计的P1-C1码偏差精度均可达到几个厘米。一个月的计算结果表明：卫星的P1-C1码偏差在一个月内变化平缓。     

《测绘法》适应性浅析

分析了新时期测绘发展面临的新形势,对《中华人民共和国测绘法》规定的有关概念内涵、管理体制、运行机制、准入制度等的适应性进行了探讨,对进一步修订《中华人民共和国测绘法》提出了建议。     

Sediment Phosphorus Chemistry and Microbial Biomass along a Lowland New Zealand Stream

An evaluation of the distribution of P concentrations in streamflow, P fractions andthe microbial biomass P pool was made of bed and bank sediments along a lowlandstream in New Zealand. Agricultural intensification increased downstream. However,most P fractions decreased downstream (total P decreased from c. 400 to 250 mg kg^-1) in bed sediments, while P in streamflow remained relatively constant (generally < 0.005 mg l^-1) and sediment microbial P increased from 2 to 8 mg kg^-1. An investigation of P release from dried and rewetted sediments showed that solution P (CaCl2-P) increased, on average > 300%, and proportional to the size of the microbial biomass P pool before drying, except in sediments with much organic carbon (OC). When supplied with a P source (1 mg l^-1) and then simultaneously with a C source (glucose, 100 mg l^-1), all sediment behaved similarly and biotic sorption accounted for, on average, 27 and 34% of the total sediment uptake, respectively (maximum of 58%). The quantity of P taken up was related to the initial size of the microbial biomass P pool, and the availability of P as influenced by organic P complexes and OC. The sediment microbial biomass represents a transient, but small store of P could be useful to indicate bioavailable P inputs.     

清溪场地区茅口组裂缝储层预测

茅口组储层以生屑灰岩储层为主,储集空间主要为溶孔、裂缝。这里运用P波振幅方位各向异性分析方法,对清溪场构造茅口组储层开展裂缝预测,搞清了裂缝发育与地层岩性以及构造发育之间的关系,明确了裂缝的走向、强度,以及密度发育部位,预测了裂缝的分布范围。实际资料应用表明,用该套方法识别裂缝—溶隙型储层是有效和可靠的,可以检测出有利的裂缝储层发育带。