考虑线状环境因子适宜性和不同机器学习模型的滑坡易发性预测建模规律

对于滑坡易发性预测中的水系、公路和断层等线状环境因子,现有研究大多采用缓冲分析提取距离线状因子的距离。但缓冲分析得到的线距离属于离散型变量,带有大小不等的随机波动性且对点或线要素的误差较为敏感,导致滑坡易发性建模精度下降。提出了使用水系和公路的空间密度等连续型变量改进线状环境因子的适宜性。以江西省安远县为例,选取高程、地形起伏度、距水系和公路距离等14个环境因子(原始因子),再将距水系和公路距离2个线状因子改进为水系密度和公路密度(改进因子);之后采用逻辑回归、多层感知器、支持向量机和C5.0决策树等机器学习模型,分别构建了基于原始因子和改进因子的机器学习模型以预测滑坡易发性;最后利用ROC曲线和易发性指数分布特征等来研究建模规律。结果表明:①改进因子机器学习预测精度均高于原始因子机器学习模型,表明空间密度对于易发性预测的适宜性更好;②在4类机器学习模型中C5.0模型对于滑坡易发性预测性能最好,其次是SVM、MLP和LR;③水系和公路两类环境因子的重要性较高且使用改进因子机器学习后这两类环境因子重要性排名依然非常靠前。

改善环境,材料产业开启绿色革命

由中国工程院化工、冶金与材料工程学部,中国材料研究学会,国家新材料产业发展战略咨询委员会联合主办的"材料产业与环境保护研讨会"召开。与会专家针对材料生产对环境污染的影响,有色、钢铁、石化、建材等材料产业自身节能减排现状,新材料如何有效治理空气、水、土壤等污染物。

Effects of Soil and Environment on Quality Traits of Purple-fleshed Sweetpotato

For the study of main traits of purple-flashed sweetpotato in different soil and ecological environments, 18 cultivars of purple-flashed sweetpotato with different enthocyenin contents were planted at Yancheng and Xuzhou separately. The main quality traits were determined. The results showed the quality traits of purple-fleshed sweetpotato were significantly influenced by soil and ecological environments. Geno- type （G）, environment （E） and genotype x environment （GxE） interaction had signif- icantiy effects on the contents of anthocyanin, dry matter, starch, protein, reducing sugar and soluble sugar in storage roots. Anthocyanin content was most easily af- fected by the environment. The E effect on anthocyanin content was greater than G and GxE effects. However, the GxE interaction effects on other 5 quality traits were greater than G and E effects. The 6 quality traits were significantly different at 1% level under different environments respectively. The contents of dry matter, starch and anthocyenin were higher in Yancheng than in Xuzhou, while the contents of protein, reducing sugar and soluble sugar were higher in Xuzhou. The variation co- efficients of all quality traits at Yancheng and Xuzhou were in the same order： an- sugar〉protein〉starch, the variation coefficient of anthocyanin content was higher in Xuzhou, and the variation coefficients of other 5 traits were higher in Yancheng. Correlation analysis showed that the reducing sugar and solu- ble sugar contents were negatively correlated with starch content, and had no sig- nifiant correlation with anthocyanin and protein contents. Dry matter content and starch content were positively correlated, and anthocyanin content and other quality traits had no significant correlation.

Environmental Stresses and Redox Status of Ascorbate

To investigate the effects of environmental stresses on ascorbic acid content and its redox status, the effects of freezing and drought on ascorbate and dehydro-ascorbate content and activities of four enzymes involved in the ascorbate-glutathione cycle in some conifers were studied. The results showed that both freezing and drought induced the decrease in ascorbate content and the increase in dehydro-ascorbate content. The activities of ascorbate peroxidase (APX) and monodehydro-ascorbate reductase (MDAR) were decreased by freezing stress. At the beginning of exposure to air, water loss from detached needles induced the increase in the activities of APX and MDAR. Further water loss turned to decrease the APX and MDAR activities. The activities of dehydro-ascorbate reductase (DHAR) and glutathione reductase (GR) were not sensitive to changes in temperature and water content of the needles. It is concluded that moderate temperature or water stresses may induce the acclimation and increase in the ability of the H2O2 scavenging system, while strong stresses decrease the ability and induce injury of plant tissues. Correlation between ascorbate content and activities of related enzymes and cold tolerance of conifers were also reported.

肿瘤干细胞与自我更新

成体干细胞是一类具有自我更新能力的细胞,他们自产生后就寄居在能够使细胞维持”干细胞”特性的龛状微环境(niche)中。肿瘤干细胞是一类能够导致肿瘤发生的具有自我更新能力的细胞,他与成体干细胞具有很多相似性,其中最重要的一点是自我更新能力。他们具有相似的自我更新调节通路,包括Bmi1、WNT以及Hedgehog等。发生在肿瘤干细胞中的突变,使原本被严密调控的自我更新呈现失控状态,是肿瘤干细胞致肿瘤过程中的重要事件。

Current situation of Chinese forestry tactics and strategy of sustainable development

Based on the analysis of the current situation of Chinese forestry and a series of ecological, environmental, eco-nomic, and social problems, this paper emphasized on the importance of forests in social and economic development in China The author pointed out that sustainable development, particularly the sustainable development of forestry, is the inevitable choice to solve the problems of ecological environment and social economics. The objectives, criteria, and strategies of sus-taining forestry were also demonstrated and expounded, from the viewpoints of ecology, economics, and sociology.

Analysis and Evaluation of Heavy Metal Environmental Quality of Irrigation Water in Vegetable Farmlands of Shandong Province

[Objective] The aim was to evaluate heavy metal environmental quality of irrigation water in vegetable farmlands of Shandong Province. [Method] Heavy metal contents including Hg,Cd,As,Cr (+6),Pb,Cu and Zn in irrigation water of main vegetable farmlands of Shandong Province were investigated by randomly sampling,and the environmental quality conditions of these heavy metals were evaluated by methods of single quality index and complex quality index. [Result] The results showed that the average contents of heavy metals in irrigation water of Shouguang,Laiyang,Jinxiang and Zhangqiu were all far lower than the limit values prescribed by 'Farmland Environmental Quality Evaluation Standards for Edible Agricultural Products' (HJ332-2006),and no heavy metal was found beyond the limit value in every sample. The single quality indices of the 7 elements in the studied 4 places were all lower than 0.5. The comprehensive quality index of the seven elements was 0.317 8 in Shouguang,0.320 4 in Laiyang,0.232 6 in Jinxiang,and 0.260 7 in Zhangqiu. The environmental quality of irrigation water in the studied four places were all set at the first class. [Conclusion] The environmental quality of irrigation water in the 4 places belonged to clean level and were fit for the plantation of no pollution vegetables.

Human Settlements in Rural-urban Fringe

On basis of human settlements theory, the research explored status quo of human settlements theory in rural-urban fringe, and analyzed and concluded predicaments confronted by rural-urban fringe, laying foundation for human settle- ments theory of rural-urban fringe.

A Heterogeneous Information Fusion Deep Reinforcement Learning for Intelligent Frequency Selection of HF Communication

The high-frequency(HF) communication is one of essential communication methods for military and emergency application. However, the selection of communication frequency channel is always a difficult problem as the crowded spectrum, the time-varying channels, and the malicious intelligent jamming. The existing frequency hopping, automatic link establishment and some new anti-jamming technologies can not completely solve the above problems. In this article, we adopt deep reinforcement learning to solve this intractable challenge. First, the combination of the spectrum state and the channel gain state is defined as the complex environmental state, and the Markov characteristic of defined state is analyzed and proved. Then, considering that the spectrum state and channel gain state are heterogeneous information, a new deep Q network(DQN) framework is designed, which contains multiple sub-networks to process different kinds of information. Finally, aiming to improve the learning speed and efficiency, the optimization targets of corresponding sub-networks are reasonably designed, and a heterogeneous information fusion deep reinforcement learning(HIF-DRL) algorithm is designed for the specific frequency selection. Simulation results show that the proposed algorithm performs well in channel prediction, jamming avoidance and frequency channel selection.

Fast Secret Key Generation Based on Dynamic Private Pilot from Static Wireless Channels

In static or quasi-static wireless channel environments, secret key generation(SKG) based on wireless channels is vulnerable to active attacks due to the openness and invariance of public pilot, especially man-inthe-middle(MITM) attacks, where attacker acts as a transparent relay to manipulate channel measurements and derive the generated keys. In order to fight against this attack, a dynamic private pilot is designed, where both private pilot and secret key are derived from the characteristics of wireless channels and private to third party. In static or quasi-static environments, we use singular value decomposition techniques to reconstitute the wireless channels to improve the randomness of the wireless channels. Private pilot can encrypt and authenticate the wireless channels, which can make channel state information intercepted by MITM attacker reduced to zero and the SKG rate close to that without attacks. Results of analysis and simulation show the proposed SKG scheme can withdraw the MITM attacks.

Heavy metal pollution and potential ecological risk in reclaimed soils in Huainan mining area

In order to determine the environmental quality condition of reclaimed soils inHuainan mining area, soil samples were collected from three representative mines, suchas Panyi Mine, Xinzhuangzi Mine and Datong Mine.The total concentration of Cd, Hg, Cu,Pb and As in the samples were analyzed.The potential ecological risk was used to evaluatethe heavy metals pollution.The investigation reveals that the reclaimed soils are contaminatedto a certain degree and the trace elements in coal gangue transferred to thesurface soil.The order of potential ecological risk is Cd>Hg>Cu>Pb>As; the pollution degreeof each sampling site is arranged in the following order: Xinzhuangzi Mine>DatongMine>Panyi Mine, and the multiform of heavy metals of potential ecological risk index is at357.35～484.62.

Analysis of Present Sperm Quality in Different Populations

To evaluate current status of male sperm quality and compare with the data of 110 cases in 1980's from same laboratory,434 fertile man and 346 cases of man with uncertain sperm quality were examined.The results showed sperm quality was significantly declined.The changes were most obvious in the sperm counts and total number of sperm,which were decreased by 54.2%～98.9% and 39.7%～114.5% respectively.Among parameters of sperm quality,motility of sperm is most affected in overall motility,a level and a+b level motility,with percentage of abnormal case were 18.4%～42.3%,37.5%～68.1% and 39.5%～75.2% respectively.The number of cases within normal range of sperm parameters was merely 33.6% for group of fertile man and 26.0% for the group of man with uncertain sperm quality.These results suggest that it should pay more attention to the decline of sperm quality.

Ecological Status and Uses of Juniper Species in the Cold Desert Environment of the Lahaul Valley, North-western Himalaya, India

The juniper species Juniperus polycarpos C. Koch, J. indica Bertol. and J. communis L. var. saxatilis （Pallas） are important elements of the forest vegetation in Lahaul valley in the north-western Himalaya. Their ability to grow under the barren and xeric conditions of cold deserts makes them particularly suited for afforestation programmes under these eeologieal conditions. In the Lahaul valley, juniper species are used as subsistence resources and for religious purposes. Excessive removal of juniper wood and leaves by the local population, overgrazing, habitat fragmentation and low regeneration potential are the main obstacles to eonservation of juniper forests in this region. The present study was carried out to assess density, basal area and importance value index （WI） of the local vegetation as well as uses and amounts of juniper wood and leaves removed from the local forests. Pressure on relict juniper forests due to grazing animals and intensive removal of wood and leaves by the loeal population was found to be greater at an altitude above 3,00o m. The results of the study demonstrated that the different juniper speeies were adapted to specific altitude ranges. A higher species density was recorded at lower altitude except for J. indica which was only present at high altitude （〉3,200 m） on south-facing slopes. Density, basal area and IVI of J. polycarpos were higher at Hinsa （2,7oo m） than at Jahlma （3,000 m）. The rapid loss of vegetation due to overuse and habitat degradation has made the eonservation of juniper forests an important priority in the Lahaul valley. J. polycarpos at loweraltitude and J. indica at higher altitude are ecologically the more suitable species for the successful implementation of conservation programmes. The support of rehabilitation programmes by regional authorities is essential for the reestablishment of the local juniper forests.

Modeling and simulation of a high-frequency micro-pump based on giant magnetostrictive material (GMM)

A new type of high-frequency micro-pump was designed, in which GMA (Giant Magnetostrictive Actuator) was employed to replace the traditional motor drive, owing to its significant characteristics of fast response, high accuracy, easily miniaturized and so on. Both the mathematic and simulation models of the micro-pump were built.A set of raw data was used for simulation studies.The results show that the micro-pump based on GMA has achieved the features of high-frequency response and high accuracy, theoretically displaying the performance merits of a giant magnetostrictive material (GMM) high-frequency micro-pump.

Some Innovations for Offshore and Harbor Berths Construction

Some new innovative constructions and piling technologies for improvement of offshore and port berthing structures are worked out and discussed. The aims of innovations are to decrease required power of construction （in particular, piling） equipment and, correspondingly, to improve environmental situation at the construction site. Another achieved goal is providing long tubular piles installation in hard soils conditions without application of very heavy and powerful driving machines. Worked out solutions are based on two approaches. One of them provides separate loading of driving force on pile＇s shaft and pile＇s tip concentrating the whole driving force on one of the mentioned parts of the pile. Another approach is focused on prevention of soil plug formation inside of the tubular pile tip facilitating the pile installation process. Also improved anchorage system for sheet piling seafront walls is presented and discussed. All considered innovations are patented and can be used in wide range of marine, offshore, coastal and harbor structures.

Scientific Basis and Technological Path of Regional Strategic Environmental Assessment

The study tries to set up a system to extract strategic environmental assessment (SEA) in exploitation of regional development based on the present situation of environmental assessment in China. First, the article summarizes the emphasis and deficiency of international academic community’s SEA research in the past 10 years. Based on this, the article puts forward the concept and evaluation principles of regional strategic environmental assessment (RSEA). Then the article expounds the necessity of carrying out RSEA. After that, the article discusses in detail the process of RSEA, which includes defining evaluation scope, describing regional background, combing strategic behavior, designing development scenarios, predicting the pressure on environment, assessing environmental impact, screening alternatives and proposing regulation and control schemes.

China’s Food Security Status:Assessment and Strategic Reflections

Based on an internationally recognized concept of food security, this paper has created a system of eight indicators to analyze China＇s food security. For the proper control and analysis of this study, the authors of this paper have chosen these indicators： supply, distribution, consumption, utilization efficiency, food security results, stability, sustainability and controllability. Results indicate that China＇s food security is currently at a high level and has been increasing in recent years. China＇s food security has multiple advantages with various indicators that include a self-sufficiency ratio, per capita calorie intake and protein supply that are above world average levels, even exceeding the average level of some developed countries. Major challenges facing China＇s food security include an unreasonable nutrition structure and poor environmental sustainability. In order to increase China＇s food security level, efforts must be made to adjust output structure, adopt an environmentally friendly pattern of production, attach importance to demand management, reduce unreasonable consumption and loss and moderately lower China＇s food reserve ratio.

Significant Effects of Fishing Gear Selectivity on Fish Life History

Over the past few decades, extreme changes have occurred in the characters of exploited fish populations. The majority of these changes have affected the growth traits of fish life history, which include a smaller size-at-age, an earlier age-at-maturation and among others. Currently, the causes of these life history traits changes still require systematic analyses and empirical studies. The explanations that have been cited are merely expressed in terms of fish phenotypic adaptation. It has been claimed that the original traits of fish can be recovered once the intensity of exploitation of the fish is controlled. Sustained environmental and fishing pressure will change the life history traits of most fish species, so the fish individual's traits are still in small size-at-age and at earlier age-at-maturation in exploited fish populations. In this paper, we expressed our view of points that fishing gear has imposed selectivity on fish populations and individuals as various other environmental factors have done and such changes are unrecoverable. According to the existing tend of exploited fish individual's life history traits, we suggested further researches in this field and provided better methods of fishery management and thereby fishery resources protection than those available early.

The Social Implications of the Degradation of the Coorong and Lower Lakes

The severe drought that Australia has endured over the past few years has impacted adversely on the environment and is the major cause of the reduction of water levels in the Coorong and Lower Lakes. The over-allocation and over-use of water in the MDB （Murray-Darling Basin） has caused the system to endure the longest period ever of reduced freshwater inflows and levels. The environmental state of Coorong and Lower Lakes is an issue that requires immediate action by governments and the surrounding community. This article will explore current data regarding the social and planning implications of the degradation of the Coorong and Lower Lakes. It primarily focuses on the social impacts that will occur if the Coorong and Lower Lakes area is significantly environmentally degraded. Drawing on Beck＇s risk theory, this paper analyses the adaptive capacity of settlements in the Coorong and Lower Lakes area and how they respond to the stresses and risks caused by environmental degradation. Economic and environmental implications will also be explored to provide an understanding of the interdependencies, This article provides a foundation and theoretical structure for further investigative research to be undertaken.

Recent Research Progress of Chemical Reactions under Supercritical Conditions

Chemical reactions (such as hydrogenation, hydroformylation, alkylation, esterification, etc.) at supercritical conditions afford opportunities to manipulate the solubility of reactants and products, to eliminate interphase transport limitations in the reaction systems, and to be beneficial to the environment. This review concentrates on the most recent developments after 2001 with only a brief summary of pioneering research work before 2001.