石油资源面临衰竭

2004年当油价攀升至50美元／桶时,世界的目光都集中到石油供给是否充足的问题上——特别是石油产量何时将达到峰值,何时又会下降。早就有分析家意识到这个问题,最近一些权威人士指出,石油产量已经逼近峰值。     

Pathogenicity of vibrios in fish: An overview

Bacteria of the genus Vibrio are ubiquitously distributed in the marine environment. Due to the rapid expansion of intensive mariculture and the consequent deterioration of culture conditions, more and more Vibrio spp. have been recognized as pathogenic agents in outbreaks of vibriosis, a serious epizootic disease affecting most wild and farmed fish species worldwide, which has become the most important limiting factor for the development of intensive mariculture industry. Attempts have been made to understand the pathogenicity of vibrios in host fish with the ultimate aim of elucidating the best means for disease control. After an extensive literature survey of the recent advances in the field of fish vibriosis, the pathological changes, virulence factors and associated potential pathogenic mechanisms, transmission routes and related environmental factors involved in outbreak of vibriosis, as well as the controlling strategies are reviewed in the present paper.     

Approaches for delineating landslide hazard areas using different training sites in an advanced artificial neural network model

The current paper presents landslide hazard analysis around the Cameron area, Malaysia, using advanced artificial neural networks with the help of Geographic Information System (GIS) and remote sensing techniques. Landslide locations were determined in the study area by interpretation of aerial photographs and from field investigations. Topographical and geological data as well as satellite images were collected, processed, and constructed into a spatial database using GIS and image processing. Ten factors were selected for landslide hazard including: 1) factors related to topography as slope, aspect, and curvature; 2) factors related to geology as lithology and distance from lineament; 3) factors related to drainage as distance from drainage; and 4) factors extracted from TM satellite images as land cover and the vegetation index value. An advanced artificial neural network model has been used to analyze these factors in order to establish the landslide hazard map. The back-propagation training method has been used for the selection of the five different random training sites in order to calculate the factor’s weight and then the landslide hazard indices were computed for each of the five hazard maps. Finally, the landslide hazard maps (five cases) were prepared using GIS tools. Results of the landslides hazard maps have been verified using landslide test locations that were not used during the training phase of the neural network. Our findings of verification results show an accuracy of 69%, 75%, 70%, 83% and 86% for training sites 1, 2, 3, 4 and 5 respectively. GIS data was used to efficiently analyze the large volume of data, and the artificial neural network proved to be an effective tool for landslide hazard analysis. The verification results showed sufficient agreement between the presumptive hazard map and the existing data on landslide areas.     

Accuracy improvement of ASTER stereo satellite generated DEM using texture filter

The grid DEM(digital elevation model) generation can be from any of a number of sources:for instance,analogue to digital conversion of contour maps followed by application of the TIN model,or direct elevation point modelling via digital photogrammetry applied to airborne images or satellite images.Currently,apart from the deployment of point-clouds from LiDAR data acquisition,the generally favoured approach refers to applications of digital photogrammetry.One of the most important steps in such deployment i...     

多光谱图象数据的无损压缩

使用标准无损图象压缩技术，能满足空间相关的需要．当处理多光谱函象数据时，在光谱相关方面也取得了少许进步．在本文中，我们提供一些新的无损压缩技术。它以简单和精巧的方式获取的光谱相关同空间相关同样地好．这些方法是基于构造树概念，它将图象划分为没有因果关系的构造模型．我们提供出自适应还原技术和自适应压缩技术。然后，又给出了相似于自适应还原技术的有效的计算方法．模拟成果说明，对于高分辨率多光谱图象，使用多光谱相关以及空间相关能有效地节省存储空间。还有，为此所付出的代价是很小的。     

空间扩散分析方法探讨

区域经济学指出:空间元素并不是以等同的,均匀的形式向周围地区扩散。通过分析区域内经济现象的空间扩散过程,我们可以发现:这种扩散过程是以某种特定的形式,而不是以随机的形式进行的,整个扩散过程是通过区域内人流、物流、信息流以及资金流来实现的。本文将通过经济元素的空间扩散过程的分析,介绍分析空间扩散形式的一种新的方法——空间倾向曲面。某一区域范围内,总有一点收入水准比周围地区高,并依次向周围地区递减。     

Trials and tribulations of playing the devil’s advocate

Beginning with his student days at school and college, the author describes his training at Cambridge with special emphasis on his mentor Fred Hoyle. His early experience of participating in a controversy at Cambridge played a major role in giving him the confidence to defend his scientific ideas. All through his later life he chose areas that were not part of mainstream research. These included the steady state theory and later the quasi steady state cosmology, action at a distance, noncosmological redshifts, quantum conformal cosmology, etc. After being a founding member of the Institute of Theoretical Astronomy(IOTA) at Cambridge, the author joined the Tata Institute of Fundamental Research(TIFR) in Mumbai and later moved to Pune to set up the Inter-University Centre for Astronomy and Astrophysics(IUCAA). He briefly reviews his own work and ends by pointing out the difficulties a non-conformist scientist faces in his professional life. In the conclusion, he mentions his interests in science popularization and science fiction for which he has won awards and appreciation, including UNESCO’s Kalinga Prize.     

Perceptions of climate change in China: The research and policy connection

Global climate change has evolved from a scientific problem into an economic and political problem oI worlOwloe rater- est. National perspectives play a crucial role in addressing climate change. Mutual understanding of perspectives is nec- essary to result in rational policies and a consensus among stakeholders with divergent interests. Conceptual frameworks for understanding the problem of climate change in China, the largest developing country and the largest greenhouse gas emitter, are of great significance to national and international efforts to address the problems of climate change. Chinese perceptions of climate change as a sustainable development problem have recently been in tension with an emerging Western perspective that frames climate change as a security issue. This paper explores Chinese perceptions of climate change as expressed in recent governmental policy statements, public opinion surveys, and academic scholarship with a focus on publications in Chinese-language journals, often unfamiliar in the West. It looks at the relationship between Chinese research and policy and finds that the Chinese policy frame of climate change as a sustainable development problem draws from the body of domestic research and is reflective of the perspectives and multidisciplinary approach of Chinese researchers in areas of climate change.     

晚白垩世全球性大洋滞流幕

通过对北大西洋深海钻探计划(DSDP)钻孔的地层和有机地球化学资料的复查校正,证明在点105、107、367、386、398、549和551处存在有CTBSH层(CTBSH为Cenomanian-Turonian Black Shale Horizon之缩写,即西诺曼期—土伦期黑色页岩层)。这套沉积物通常含黄铁矿或磷酸盐,或者两者都含,其层厚为1毫米或小于1毫米的纹层。它的总有机炭含量(TOC—Total Organic Carbon之缩写,即总有机炭)大于2%,平均值一般为10%,最大值可达30%,所含有机质主要是海相成因的。     

无定形氢氧化铝的表面酸度

通过酸碱滴定法以及分析反应后的溶液和反应后固体的XRD表征等方法测定了合成氢氧化铝的表面酸度。XRD结果表现出4个宽峰,说明合成产物是无定形的。滴定实验的固体产物的XRD的分析表明,无定形的氢氧化铝在碱性的环境下(pH>10),迅速转化成为结晶的三羟铝石。滴定过程中和反应后的溶液分析计算出无定形氢氧化铝的溶解度,为1010.3。滴定实验中加入的酸或碱与溶解的铝和其表面羟基发生质子化作用或脱质子化作用。表面酸度常数,表面羟基密度和比表面积用FITEQL4.0进行了评价。无定形氢氧化铝的表面酸度@K.FUKUSHI$Research Center for…