The preservation potential of some recent stromatolites

Stromatolites are laminated organo-sedimentary structures, generally compared to present day blue-green algal mats. Their morphology, species composition and overall extent are largely governed by the amount of wetting, although other factors such as competition, predation and desiccation, also contribute. The Trucial Coast mats are essentially intertidal. Stromatolite accretion rates in this area are of the order of 0·2 mm p.a. but lamina growth is far from regular. The area is also characterized by the development of evaporites, especially gypsum which proves to be an important agent of mat destruction. The growth of crystals causes disruption within the upper portions of the stromatolite section with the result that none of the upper intertidal mat forms are preserved. Other agencies of destruction include bacterial decay, desiccation and dehydration, and compaction under burial which may depress and deform the original mat relief. Decay results in the almost total loss of cellular contents, only a few empty sheaths and the pigment surviving into the fossil record. Preservation may be effected via (a) burial or (b) lithification. However, few modern algal mat structures bear any resemblance to fossil stromatolite heads with the exception of those from Shark Bay. From this, one might infer that pene-contemporaneous lithification is a prerequisite for their preservation.     

Incorporating Cellular Automata simulators as analytical engines in GIS

Contemporvy GIS suffer from a variety of problems. These include poor ability to handle dynamic spatial models, poor performance for many operations, and poor handling of the temporal dimension. Cellular Automata (CA) are dynamic mathematical systems based on discrete time and space. While CA have many similarities to GIS, and indeed excel in many areas in which GIS are deficient, they cannot themselves be considered as GIS since they lack the necessary sophisticated Capabilities in data input, data storage and retrieval, and data output. However, the advantages of CA in data analysis and modelling are significant. In order to exploit fully the advantages of each system - GIS and CA - we have developed a methodology and prototype system for coupling GIS and CA, in which the CA serves as an alternative analytical engine for the GIS. In the prototype system, spatial, temporal (i.e. time series), and spatio-temporal filters as well as spatial diffusion operators are developed. In addition, the integrated system provides a flexible framework for the programming and running of dynamic spatial models. We conclude that CA represent a viable alternate analytical engine for GIS and provide increased ability for dynamic spatial modelling within GIS.     

A note on the significance of lamination in stromatolites

The lamination found in recent stromatolites, an intrinsic feature of many of them, comprises a number of sediment-rich and organic-rich couplets. The significance of this lamination has figured in at least two avenues of research. In one is its possible influential role upon geochemical and diagenetic trends, in the other its possible calendar role. Algal growth follows a diurnal pattern but sedimentation, which is largely marine, is far less regular or predictable. The monitoring of modern algal mat surfaces has yielded much useful and accurate information concerning rates of mat accretion. Millimetre-scale lamination may be produced on a number of interacting processes but as yet no one has been able to determine with any great assurance whether it represents a daily, monthly, annual or some other regular periodic growth. The evidence from the Trucial Coast tends to show, rather, that burial, subsequent compaction, distortion and, in the case of sabkha-type sections, destruction owing to evaporite mineral growth, all tend to obliterate or at best mask any regular patterns of growth. In conclusion, one is forced to acknowledge that any computations concerning the calendar role of stromatolites are to be regarded with the utmost suspicion.     

Antiproliferative and apoptosis-inducing potential of 3β-hydroxy-△5-steroidal congeners purified from the soft coral Dendronephthya putteri

The exploration and identification of antiproliferative phytochemicals have received increased attention in medicinal chemistry.In particular,research focused on the toxicology of marine natural products has increased in recent years.Terpenoids,among many secondary metabolites,have been demonstrated to act as effective anticancer agents.Soft corals,a group of marine invertebrates,produce a variety of terpenoids with biofunctional properties.The current study presents the extraction,purification,and identification of sterol congeners from the soft coral Dendronephthya putteri.The method involves 50%chloro form-methanol extraction,polar column fractionation,and analy sis through GC-MS~n.Do se-dependent antiproliferative activity was observed within the sterol-rich fraction(DPCMH 2-4),which consisted of3β-hydroxy-A5-steroidal congeners.This fraction inhibited the growth of HL-60 and MCF-7 cells with IC_(50) values of 25.27±1.43 and 22.81±0.15 μg/mL,respectively.Apoptotic body formation,DNA damage,cell cycle arrest,and apoptotic cell signaling pathway activation were also observed,reinforcing the dosedependent antiproliferative and apoptosis-inducing activity of 3β-hydroxy-A5-steroidal congeners.To our knowledge,this is the first report of anticancer agent identification from the soft coral D.putteri.Based on the observations,these steroidal congeners are promising candidates for the development of anticancer drugs.     

Integration of the nuclease protection assay with sandwich hybridization (NPA-SH) for sensitive detection of Heterocapsa triquetra

Microalgae are photosynthetic microorganisms that function as primary producers in aquatic ecosystems. Some species of microalgae undergo rapid growth and cause harmful blooms in marine ecosystems. Heterocapsa triquetra is one of the most common bloom-forming species in estuarine and coastal waters worldwide. Although this species does not produce toxins, unlike some other Heterocapsa species, the high density of its blooms can cause significant ecological damage. We developed a H. triquetra species-specific nuclease protection assay sandwich hybridization(NPA-SH) probe that targets the large subunit of ribosomal RNA(LSU r RNA). We tested probe specificity and sensitivity with five other dinoflagellates that also cause red tides. Our assay detected H.triquetra at a concentration of 1.5×104 cells/m L, more sensitive than required for a red-tide guidance warning by the Korea Ministry of Oceans and Fisheries in 2015(3.0×104 cells/m L). We also used the NPA-SH assay to monitor H. triquetra in the Tongyeong region of the southern sea area of Korea during 2014. This method could detect H.triquetra cells within 3 h. Our assay is useful for monitoring H. triquetra under field conditions.     

Petrogenesis of the Paleoproterozoic Guandishan Granitoids in Shanxi Province： Constraints from Geochemistry and Nd Isotopes

The Guandishan granitoids consist mainly of various granitoid intrusions with different scales, including the Huijiazhuang intrusion, Shizhuang intrusion and Hengjian intrusion, which were formed between 1906 Ma and 1848 Ma. On the basis of geological and petrological characteristics, these granitoids can be classified into two groups： the earlier gneissic granodiorites and monzogranites, and the later massive leuco-monzogranites. Their geochemical and Nd isotopic features indicate that they could be derived from complicated partial melting of supracrustal rocks with an affinity of continental arc materials, such as sandy shale and pelite, and with garnet, pyroxene, hornblende and plagioclase as residual phases. Biotite, feldspar and other minerals were most likely fractionated during the magma evolution. Their source may have an affinity with continental arcs, and the granitoids could be derived from the main syn-collisional to late-orogenic tectonic environment, which may be related to the final amalgamation between the Eastern and Western continental blocks in the North China Craton.     

韩国济洲岛下西归浦组的时代及其古环境

韩国济洲岛下西归浦组的时代归属一直存在着争论。该段地层中浮游有孔虫 Globigerina calida calida、Beella digitata、 Globigerina bermudezi和 Globoquadrina conglomerata的发现表明了它应为中更新世 (晚 N 2 2带、即 Globigerina calida calida亚带 ,不晚于 40万年前 )的沉积。底栖、浮游有孔虫的定量统计分析揭示了下西归浦组沉积环境的变化 :下部的沉积环境为岸外中陆架暖水 ,而向上则演变成近岸内陆架温凉水。有孔虫组合的更替反映了下西归浦组沉积是一个由次一级的 3个亚海退和 2个亚海进组成的海退序列。     

Spatio-temporal variability in sea surface wind stress near and off the east coast of Korea

Sea surface wind stress variabilities near and off the east coast of Korea, are examined using 7 kinds of wind datasets from measurements at 2 coastal (land) stations and 2 ocean buoys,satellite scatterometer (QuikSCAT), and global reanalyzed products (ECMWF,NOGAPS,and NCEP/NCAR). Temporal variabilities are analyzed at 3 frequency bands; synoptic (2-20 d), intra-seasonal (20-90 d),and seasonal (>90 d).Synoptic and intra-seasonal     

Evaluation of Heavy Rainfall Model Forecasts over the Korean Peninsula Using Different Physical Parameterization Schemes and Horizontal Resolution

In this study, the accuracy of a Pennsylvania State University-National Center for Atmospheric Research mesoscale model (PSU/NCAR MM5) for predicting heavy summer precipitation over the Korean Peninsula was investigated. A total of 1800 simulations were performed using this model for 30 heavy rainfall events employing four cumulus parameterization schemes (CPS), two grid-scale resolvable precipitation schemes (GRS), and two planetary boundary layer (PBL) schemes in three model resolutions (90 km, 30 km, and 10 km). The heavy rainfall events were mesoscale convective systems developed under the influence of mid-latitude baroclinic systems with low-level moisture transport from the ocean. The predictive accuracy for maximum rainfall was approximately 80% for 10-km resolution and was 60% for 30-km resolution. The predictive accuracy for rainfall position extended to ～150 km from the observed position for both resolutions. Simulated rainfall was most sensitive to CPS, then to PBL schemes, and then to GRS. In general, the Grell (GR) scheme and the Anthes and Kuo (AK) scheme showed a better prediction capability for heavy rainfall than did the Betts-Miller (BM) scheme and the Kain-Fritsch (KF) scheme. The GR scheme also performed well in the 24-h and 12-h precipitation predictions: the parameterized convective rainfall in GR is directly related to synoptic-scale forcing. The models without CPS performed better for rainfall amounts but worse for rainfall position than those with CPS. The MM5 model demonstrated substantial predictive capacity using synoptic-scale initial conditions and lateral boundary data because heavy summer rainfall in Korea occurs in a strong synoptic-scale environment.