Natural Anthraquinone Derivatives from a Marine Mangrove Plant-Derived Endophytic Fungus Eurotium rubrum: Structural Elucidation and DPPH Radical Scavenging Activity

There is considerable interest in the isolation of potent radical scavenging compounds from natural resources to treat diseases involving oxidative stress. In this report, four new fungal metabolites including one new bisdihydroanthracenone derivative (1, eurorubrin), two new seco-anthraquinone derivatives [3, 2-O-methyl-9-dehydroxyeurotinone and 4, 2-O-methyl4-O-(alpha-D-ribofuranosyl)-9-dehydroxyeurotinone], and one new anthraquinone glycoside [6,3-O-(alpha-D-ribofuranosyl)questin], were isolated and identified from Eurotium rubrum, an endophytic fungal strain that was isolated from the inner tissue of the stem of the marine mangrove plant Hibiscus tiliaceus. In addition, three known compounds including asperflavin (2), 2-O-methyleurotinone (5), and questin (7) were also isolated and identified. Their structures were elucidated on the basis of spectroscopic analysis. All of the isolated compounds were evaluated for 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity.

Impacts of anthropogenic activity on the recent evolution of the Huanghe (Yellow) River delta

Hydrological statistical data, remote sensing images, and bathymetric charts were used to study the recent evolution of the Huanghe (Yellow) River delta under human-induced interventions. It was clear that water and sediment discharge from the Huanghe River had dropped rapidly since 1970, particularly after 1986. The water and sediment discharges for the period of 1986-2000 were found to have been reduced to only 29.2% and 31.2% of those in the period of 1950-69. This was caused by human factors in the upper and middle reaches of the Huanghe River, including water diversion, damming and reservoir construction, and water and soil conservation. Based on the results from visual interpretation of processed Landsat (MSS or TMJETM+) images dated from 1976 to 2001 and two digital elevation models generated from bathymetric charts surveyed in 1976 and 1992, we found that human-induced reduction of water and sediment discharge led to coastline retrogradation, with the maximum mean recession rate of -0.51 km yr-1 over the period of 1976-98, and seabed erosion beyond the -20 m isobath between 1976 and 1992. Other impacts of human activities on the recent evolution of the Huanghe River delta, including tidal flats shrinking, artificial coastline increasing, land surface sinking and so on, were also analyzed. We found that: (i) the whole delta, including subaerial and subaqueous, has turned from a highly constructive period to a destructive phase; (ii) channelization and dredging were two of the main causes of delta destruction; (iii) land loss in the Huanghe River delta caused by submersion will be increased in the near future; (iv) the Huanghe River delta was becoming more fragile and susceptible to natural hazards.

淤泥质潮滩地貌的遥感研究－以苏北辐射沙洲海岸为例

本文以具有典型特征的苏北淤泥质潮滩海岸作为研究区，利用1975-2003年间14景覆盖该地区的Landsat和SPOT卫星影像作为主要数据源，结合地面调查和验证工作，在遥感影像处理和地理信息系统分析技术的支持下，对区内潮滩、岸线、水边线和盐沼植被等进行遥感解译，分析苏北辐射沙脊群和沿岸地貌的空间分布特征和动态演变趋势。研究结果表明：苏北辐射沙脊群海域的潮汐水位过程的不同步现象普遍存在，限制了常规遥感数据在苏北潮滩地貌研究中的适用范围和解译精度；在人工判别的辅助下，多光谱遥感的非监督分类方法可以有效解译淤泥质潮滩的水边线；利用修改型土壤调整植被指数（MSAVI）可以较好地提取潮滩上的盐沼植被信息；苏北沿岸潮滩的快速淤长促进了盐沼植被带向海侧快速扩展，近年来持续的潮滩围垦工程则不断从陆侧侵占盐沼植被带，使盐沼植被带宽度减小乃至消失；在大规模人类活动和自然条件的共同影响下，苏北辐射沙脊群海岸的岸线发育趋于平直化，无序的潮滩围垦项目使得可垦滩地资源被过度消耗；1975～2002年间，研究区北部和南部沿岸的高潮滩整体上处于淤长状态，中部沿岸潮滩和离岸沙洲高潮滩则被大面积侵蚀；1999年以来，研究区内低潮滩部位开始形成有序排列的滩面地物，并表现出逐年大面积蔓延的趋势，可能是滩涂紫菜养殖区扩展的结果。

滑坡泥石流信息遥感获取与空间预测

On the issue of geological hazard evaluation（GHE）, taking remote sensing and GIS systems as experimental environment, assisting with some programming development, this thesis combines multi-knowledges of geo-hazard mechanism, statistic learning, remote sensing (RS), high-spectral recognition, spatial analysis, digital photogrammetry as well as mineralogy, and selects geo-hazard samples from Hong Kong and Three Parallel River region as experimental data, to study two kinds of core questions of GHE, geo-hazard information acquiring and evaluation model. In the aspect of landslide information acquiring by RS, three detailed topics are presented, image enhance for visual interpretation, automatic recognition of landslide as well as quantitative mineral mapping. As to the evaluation model, the latest and powerful data mining method, support vector machine (SVM), is introduced to GHE field, and a serious of comparing experiments are carried out to verify its feasibility and efficiency. Furthermore, this paper proposes a method to forecast the distribution of landslides if rainfall in future is known baseing on historical rainfall and corresponding landslide susceptibility map. The details are as following: (a) Remote sensing image enhancing methods for geo-hazard visual interpretation. The effect of visual interpretation is determined by RS data and image enhancing method, for which the most effective and regular technique is image merge between high-spatial image and multi-spectral image, but there are few researches concerning the merging methods of geo-hazard recognition. By the comparing experimental of six mainstream merging methods and combination of different remote sensing data source, this thesis presents merits of each method ,and qualitatively analyzes the effect of spatial resolution, spectral resolution and time phase on merging image. (b) Automatic recognition of shallow landslide by RS image. The inventory of landslide is the base of landslide forecast and landslide study. If persistent collecting of landslide events, updating the geo-hazard inventory in time, and promoting prediction model incessantly, the accuracy of forecast would be boosted step by step. RS technique is a feasible method to obtain landslide information, which is determined by the feature of geo-hazard distribution. An automatic hierarchical approach is proposed to identify shallow landslides in vegetable region by the combination of multi-spectral RS imagery and DEM derivatives, and the experiment is also drilled to inspect its efficiency. (c) Hazard-causing factors obtaining. Accurate environmental factors are the key to analyze and predict the risk of regional geological hazard. As to predict huge debris flow, the main challenge is still to determine the startup material and its volume in debris flow source region. Exerting the merits of various RS technique, this thesis presents the methods to obtain two important hazard-causing factors, DEM and alteration mineral, and through spatial analysis, finds the relationship between hydrothermal clay alteration minerals and geo-hazards in the arid-hot valleys of Three Parallel Rivers region. (d) Applying support vector machine (SVM) to landslide susceptibility mapping. Introduce the latest and powerful statistical learning theory, SVM, to RGHE. SVM that proved an efficient statistic learning method can deal with two-class and one-class samples, with feature avoiding produce ‘pseudo’ samples. 55 years historical samples in a natural terrain of Hong Kong are used to assess this method, whose susceptibility maps obtained by one-class SVM and two-class SVM are compared to that obtained by logistic regression method. It can conclude that two-class SVM possesses better prediction efficiency than logistic regression and one-class SVM. However, one-class SVM, only requires failed cases, has an advantage over the other two methods as only "failed" case information is usually available in landslide susceptibility mapping. (e) Predicting the distribution of rainfall-induced landslides by time-series analysis. Rainfall is the most dominating factor to bring in landslides. More than 90% losing and casualty by landslides is introduced by rainfall, so predicting landslide sites under certain rainfall is an important geological evaluating issue. With full considering the contribution of stable factors (landslide susceptibility map) and dynamic factors (rainfall), the time-series linear regression analysis between rainfall and landslide risk mapis presented, and experiments based on true samples prove that this method is perfect in natural region of Hong Kong. The following 4 practicable or original findings are obtained: 1) The RS ways to enhance geo-hazards image, automatic recognize shallow landslides, obtain DEM and mineral are studied, and the detailed operating steps are given through examples. The conclusion is practical strongly. 2) The explorative researching about relationship between geo-hazards and alteration mineral in arid-hot valley of Jinshajiang river is presented. Based on standard USGS mineral spectrum, the distribution of hydrothermal alteration mineral is mapped by SAM method. Through statistic analysis between debris flows and hazard-causing factors, the strong correlation between debris flows and clay minerals is found and validated. 3) Applying SVM theory (especially one-class SVM theory) to the landslide susceptibility mapping and system evaluation for its performance is also carried out, which proves that advantages of SVM in this field. 4) Establishing time-serial prediction method for rainfall induced landslide distribution. In a natural study area, the distribution of landslides induced by a storm is predicted successfully under a real maximum 24h rainfall based on the regression between 4 historical storms and corresponding landslides.

浑善达克沙地与河北沽源地区土地沙漠化研究

The Otindag sandy land and the Guyuan region of Hebei Province lie in the agro-pastoral zone, where sandy desertification is serious. So they are typical for us to study on. In this paper, detail investigation were made on the Remote Sensing, Hydrochemistry, Chronology, grain size analyzing of research region to monitor sandy desertification and environmental background. The main conclusions are presented as following: 1. According to the diverse natural condition, the research area is divided into three types as sandy land desertification, cultivated land desertification and desertification reflected by lake change. The monitoring result of the first type shows that the main performance way of the sandy desertification in Otindag sandy land is that (1) the expansion of both the shifting dune and the half fixed sandy dune, (2) the reduce of the fixed sandy dune. While the result of the second type shows (1) the desertification land in the Guyuan region has first increasing then reducing change for about 30 years. (2) The sand mainly concentrates west of the research area and small part of wind-drift sand distributes northeast the research area with the spot shape. (3) The meadow area increases obviously. As far as the third type, the Dalai Nur lake area occurs first expanding then reducing change and the wind-drift sand around the lake first reduces then increases. 2. The land cover of the different types change with the same law. It is worth notice that the lake area changes oppositely with that of the wind-drift sand. 3. For about 5,000 a B.P. -2800 a B.P., the well developed palaeosols emerged. After that, three layer palaeosols were founded in the profile of Otindag sandy land. The analyses of grain size show that the sand grains of the south were coarser than that of the north. The sand in the north and middle were well sorted, while the south poor sorted. 4. Both the natural and human impact on the process of sandy desertification. On this research result, different regions have different influences. So the measures to improve sandy desertification should be choosed respectively.