Cytoplasmic regionalization in starfish oocyte occurrence and localization of cytoplasmic determinants responsible for the formation of archenteron and primary mesenchyme in starfish (asterias amurensis) oocytes

Starfish oocytes with intact germinal vesicles (GVs) were cut along desired planes with glass needles or ligated using silk thread loops into two parts and allowed to mature in vitro, and inseminated. The experimental results showed that (1) only the parts with GVs or partial GV contents (PGVCs) cleaved, those without any GV materials did not; but nucleated and non-nucleated fragments cut from mature eggs were able to divide; (2) the development of animal parts of oocytes containing GVs or PGVCs was like that of animal fragments of matured oocytes with female pronuclei; most of them gave rise to permanent blastulae, and just a few formed ectodermal vesicles with a little primary mesenchyme; (3) a large part of vegetal fragments with GVs or PGVCs, and the vegetal parts of mature eggs without female pronuclei developed into small but normal embryos; (4) the fragments containing GVs or PGVCs obtained from the oocytes along a plane parallel to the animal-vegetal (A-V) axis developed as normally as the halves (with or without female pronuclei) severed from mature eggs along the same axis. Based on the data above, it was concluded that (1) the non-chromatin materials in the oocyte GVs are indispensable for successful fertilization and cleavage of starfish eggs; (2) some factor (s) located asymmetrically in the vegetal hemispheres of starfish oocytes is (are) responsible for formation of the archenteron and primary mesenchyme. It is evident from the above findings that the oocyte cytoplasm of the starfish had already regionalized before the GV break-down. Contribution No. 1722 from the Institute of Oceanology, Academia Sinica     

A Time Evolution Study of the Superhumps of the Dwarf Nova 1RXS J232953.9+062814 by Wavelet Transform

The time evolution behaviour of the superhumps of the dwarf nova1RXS J232953.9+ 062814 is investigated with the wavelet analysis method. On the basis of two nights CCD photometry performed during its first superoutburst as well as other published brightness data, we reveal the superhump's time-dependence as a function of periods and time. Our light curves, which phased in the rapid decay ending portion of the superoutburst and in the dawn of a following normal outburst, are important to help trace the superhump evolution for the star. Both the superhump period and the orbital period of the binary system are detected in the present data. We obtain P _sh=0.0458±0.0002d and P _orb=0.0450±0.0002d. They agree with those existing values. The two periods exchanged their roles during the superhump evolution. The general profile of brightness fading over the outbursts roughly followed an exponential decay law or a form of a five-order polynomial. This revised version was published online in July 2006 with corrections to the Cover Date.     

Numerical manifold method for dynamic nonlinear analysis of saturated porous media

It is well known that the Babuska–Brezzi stability criterion or the Zienkiewicz–Taylor patch test precludes the use of the finite elements with the same low order of interpolation for displacement and pore pressure in the nearly incompressible and undrained cases, unless some stabilization techniques are introduced for dynamic analysis of saturated porous medium where coupling occurs between the displacement of solid skeleton and pore pressure. The numerical manifold method (NMM), where the interpolation of displacement and pressure can be determined independently in an element for the solution of u–p formulation, is derived based on triangular mesh for the requirement of high accurate calculations from practical applications in the dynamic analysis of saturated porous materials. The matrices of equilibrium equations for the second‐order displacement and the first‐order pressure manifold method are given in detail for program coding. By close comparison with widely used finite element method, the NMM presents good stability for the coupling problems, particularly in the nearly incompressible and undrained cases. Numerical examples are given to illustrate the validity and stability of the manifold element developed. Copyright © 2006 John Wiley & Sons, Ltd.     

四川石棉独立碲矿床蚀变岩的地质地球化学研究

四川石棉大水沟独立碲矿床堪称世界首例，其矿体两侧的围岩蚀变较窄，且蚀变带与矿脉及未蚀变岩呈清楚而截然的接触关系。主要围岩蚀变为白云石化、白（绢）云母化、云英岩化及电气石化等。这些蚀变作用分别发生于１７７．７～１６５．１Ｍａ和９１．７１～８０．１９Ｍａ。蚀变作用过程中ＳｉＯ２大量析出，Ａｌ２Ｏ３、ＴｉＯ２、ＣａＯ、ＭｇＯ、Ｋ２Ｏ、Ｈ２Ｏ、ＣＯ２、Ｆｅ２Ｏ３、ＭｎＯ则有不同程度地带入。与此同时，ＲＥＥ在此过程中包集体迁出，Ｔｅ、Ｂｉ、ＡＳ等元素的含量则决定于蚀变作用及其强度，而与原岩无关。     

Luminescence dating of sand–loess sequences and response of Mu Us and Otindag sand fields (north China) to climatic changes

The sand–loess transition zone in north China is sensitive to climate change, and is an ideal place to investigate past environmental changes. However, past climate change at millennial–centennial timescales in this region has not been well reconstructed because of limited numerical dating. Alternations of sandy loam soils with aeolian sand layers in the Mu Us and Otindag sand fields, which lie along the sand–loess transition zone, indicate multiple intervals of dune activity and stability. This change is probably a response to variations of the East Asian monsoon climate during the late Quaternary. The single aliquot regeneration (SAR) optically stimulated luminescence (OSL) dating protocol, which has been successfully applied to aeolian deposits worldwide, is applied to these two sand fields in this study. The OSL ages provide reliable constraints for reconstruction of past climate changes at suborbital timescale. Sections in both sand fields contain aeolian sand beds recording millennial‐scale episodes of dry climate and widespread dune activation, including episodes at about the same time as Heinrich Event 5 and the Younger Dryas in the North Atlantic region. These results demonstrate the potential of aeolian sediments in semi‐arid north China to record millennial‐scale climatic events, and also suggest that dry–wet climate variation at the desert margin in China may be linked to climatic change elsewhere in the Northern Hemisphere, through atmospheric circulation. This article was published online on 27 November 2008. An error was subsequently identified. This notice is included in the online and print versions to indicate that both have been corrected (16 December 2008). Copyright © 2008 John Wiley & Sons, Ltd.     

INVERSE DDA OF A SYSTEM OF BLOCKS IN SPHERE COORDINATES

1　IntroductionDiscontinuousDeformationAnalysis(DDA)developedbyShiin 1 980’s[1 ,2 ] maybeusedtocalculatethedeformationanddisplacementsinamulti blocksystemandtoanalyzetherelationbe tweenforcesanddisplacementsinthesystem .Ifthesurveydisplacementofeverypointordirectionisknown,alldisplacementsanddeformationsofblocks,eventheglide ,theclosureandthestretchoftheboundary planeofblocks ,canbecalculated .TheresultisoptimallyfittedaccordingtotheLeastSquarePrinciple.DDAismainlyusedinrockblockssystems…     

A THREE-DIMENSIONAL ELASTIC NESTED-GRID MESO-(β-γ)SCALE ATMOSPHERIC MODEL——PARTI:MODEL DESCRIPTION

A three-dimensional elastic nonhydrostatic mesoscale(β-γ)model with nested-grid is presented.It uses a set of fullequations in terrain-following coordinates as its basic dynamic frame,which is solved with a time-splitting algorithmfor acoustic and gravity waves.The model physical parameterization includes a K-theory subgrid eddy mixing for cloudand free atmosphere,a bulk planetary boundary layer parameterization,and three types of sofisticated cloudmicrophysics schemes with double-parameters for hail-bearing clouds,warm clouds and snowing clouds respectively.The model is designed to be used flexibly for simulations of a variety of meso-and small-scale atmospheric processes,and can be improved as a regional and local operational NWP system in future.     

中国石油生产的展顾

本文分析了中国石油生产近20年变化的原因,对一些学者认为80年代中国会成为超级产油大国,后又悲观断定80年代中国可能变成石油净进口国作了评述。同时对90年代中国石油生产前景作了初步展望。     

The evolution of quasars selected by slitless technique

In former works (Zhouet al., 1983, 1985), a quantitative method have been developed to take the selection effects in the identification of emission lines of quasars into account. It was proved that these selection effects may be the cause of the unevenness in the redshift distribution of quasars. The present work is a continuation and development of former works. We use results given by the surveys with same limit-apparent magnitude and choose the quasars whose absolute magnitudes are within a specific range as the analysing samples. Using the method given in the former papers we may find out the evolutionary parameter in an evolutionary law with form of (1+z) ^y from the best fitting between the calculative and observational redshift distribution. The result of analysis shows that the evolutionary law of quasars selected by slitless technique isp =p ₀(1 + z)^{6.5 ± 1} up toz=2.8. This result coincides with and generalizes the earlier result given by other authors.