Sponges (Porifera) as living metazoan witnesses from the Neoproterozoic: biomineralization and the concept of their evolutionary success

The emergence of the Metazoa can be dated back to the Neoproterozoic Era which comprises the Cryogenian Period during which two major glaciations occurred, the Sturtian and the Varanger-Marinoan. At that time, the phylum Porifera (sponges) evolved as the first animals and developed a hard skeleton. The two classes of siliceous sponges, the Hexactinellida and the Demospongiae, are already provided with the major genetic repertoire and gene regulatory networks that also exist in modern multicellular animals. Besides these metazoan innovations, the siliceous sponges display one autapomorphic character, silicatein, an enzyme which mediates bio-silica formation. Well preserved siliceous sponge fossils have been excavated from the Cambrian Burgess Shale- and Chengjiang deposits. It is concluded that it was the hard skeleton of the siliceous sponges that contributed to the successful evolution and survival of the Porifera during the last 500 Ma.     

Volcanic ash over the Russian Federation territory after the volcanic eruption in Iceland on April 14, 2010 from the data of model simulations and observations

After the volcanic eruption in Iceland on April 14, 2010, the volcanic ash cloud spread over Europe including Russia, that resulted in the air traffic collapse for several days. Presented are the results of computations of the volcanic ash spreading obtained with the FLEXPART Lagrangian dispersion model, as well as the results of the lidar sounding over Troitsk (Moscow region). The obtained model and experimental results agree well with each other and indicate the existence of settling layer of volcanic ash at the height of 4?C6 km, that is corroborated by the data of observations in Europe. The largest uncertainty in the model computations is caused by the lack of information on the volume of the emission of micron particles transported with the wind to the large distance. The comparison of model results with the observational data can enable to correct the source function and to obtain more realistic estimates of volcanic ash concentrations, that is a key factor of the air traffic control.     

北京市电网灾害的时空分布特征及与气象因素的关系

根据北京电力试验研究院提供的北京市1996—2009年逐日电网灾害资料,采用统计分析的方法研究了该市电网灾害的时空分布特征及其成因,结果表明：电网灾害的灾种分布中雷暴造成电网灾害（后文简称雷害）的比例最大,占电网灾害总数的71.3%,其次为风害和覆冰,三者之和占北京市电网灾害总数的92.1%;从地域分布上看多发区主要集中西部的房山和北部的延庆、昌平、密云、朝阳等地区,而南部的大兴、通州的电网灾害则相对较少;从月分布可以看到电网灾害主要发生在6—9月,主要的几种电网灾害均呈现出不同的月变化特征。     

一种利用加窗LSSVM拟合GPS在轨卫星钟差的算法

利用最小二乘支持向量机(least squares support vector machine,LSSVM)来对GPS在轨卫星钟差数据进行拟合,针对LSSVM拟合钟差两端发散的现象,利用加窗的方法进行抑制。采用IGS提供的精密钟差进行算例分析,发现加窗LSSVM钟差拟合算法比现有的钟差拟合算法精度更高,且基于多项式的核函数比较适合加窗LSSVM钟差拟合。     

Probability distribution of the Murty‐Loomis tsunami magnitude

Abstract

In 1980, Murty and Loomis proposed a new, objective tsunami magnitude scale based on total tsunami energy. A list of 178 tsunamigenic earthquakes during the period 1815 to 1974 was given along with estimated tsunami magnitudes. In this study, we derived the probability distribution function of tsunami magnitudes based on the assumptions that (1) the occurrences of tsunamigenic earthquakes are a Poisson process, and (2) tsunami energy is a polynomial function of tsunami recurrence time. Using the data given by Murty and Loomis, the parameters of the distribution function are estimated. Comparison with the data shows that the derived distribution is a good representation of the distribution of the Murty‐Loomis tsunami magnitude.     

201002号台风“康森”移动路径特点的分析

通过对台风"康森"路径特点和影响因素的分析,特别是影响台风移动的诸多因子及其对"康森"西行北折路径所起的作用分析,发现:东亚中高纬度贝加尔湖一带为有阻塞高压的长波脊,副热带高压呈带状形势,强度强,稳定,西伸脊点偏西是"康森"稳定西偏北行的主要原因;而大尺度环境场的调整如加尔湖阻塞高压减弱、崩溃,高空槽东移加深,副高减弱东退南落,是"康森"西行北折的主要原因。同时台风中心及附近850hPa涡度场、700hPa风场的分布,对流云的发生发展也影响"康森"的移动路径。     

盾构机激光导向系统原理

以德国VMT公司的单圆盾构机为例,介绍盾构机和激光导向系统的组成,探讨激光导向系统的工作原理.重点揭示激光导向系统的测绘学原理.总结提高激光导向系统测量精度应采取的措施.     

A model of magnetically induced disc–corona for black hole binaries

We propose a model of magnetic connection (MC) of a black hole with its surrounding accretion disc based on large-scale magnetic field. The MC gives rise to transport of energy and angular momentum between the black hole and the disc, and the closed field lines pipe the hot matter evaporated from the disc, and shape it in the corona above the disc to form a magnetically induced disc–corona system, in which the corona has the same configuration as the large-scale magnetic field. We numerically solve the dynamic equations in the context of the Kerr metric, in which the large-scale magnetic field is determined by dynamo process and equipartition between magnetic pressure and gas pressure. Thus we can obtain a global solution rather than assuming the distribution of large-scale magnetic field beforehand. The main MC effects lie in three aspects. (1) The rotational energy of a fast-spinning black hole can be extracted, enhancing the dissipation in the accretion disc, (2) the closed field lines provide a natural channel for corona matter escaping from disc and finally falling into black hole and (3) the scope of the corona can be bounded by the conservation of magnetic flux. We simulate the high-energy spectra of this system by using Monte Carlo method, and find that the relative hardness of the spectra decreases as accretion rate or black hole spin a _* increases. We fit the typical X-ray spectra of three black hole binaries  (GRO J1655−40, XTE 1118+480 and GX 339−4)  in the low/hard or very high state.