10 February 2007, Volume 25 Issue 0703
    

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  • . 2007, 25(0703): 5-12.
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    The social and academic influence of an institution of higher learning or a research institute may be measured by their positions in national important societies. In this paper, a reference is made of China Association for Science and Technology and various national societies under CAST. A ranking is worked out for 100 major institutions of higher learning and research institutes in China according to the posts taken by their staff in the above mentioned association and various societies. The first 10 institutions of higher learning are Tsinghua University, Peking University, Zhejiang University, China Agricultural University, Shanghai Jiao Tong University, Fudan University, Beihang University, Nanjing University, Xi'an Jiaotong University, Sichuan University and Tongji University (the last two hold the tenth position jointly); the first 10 research institutes are Institute of Zoology of CAS, Academy of Military Medical Sciences, Academy of Mathematics and Systems Science of CAS, Institute of Geology and Geophysics of CAS, Institute of Acoustics of CAS and Chinese Academy of Social Sciences (the three hold the fourth position jointly), Institute of Geographical Sciences and Natural Resources of CAS, Institute of Botany of CAS, National Institute of Metrology of China, China Academy of Geological Science and China Academy of Chinese Medical Sciences (the two hold the tenth position jointly) .
  • . 2007, 25(0703): 13-17.
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    Major scientific findings in astronomy and astrophysics in 2006 are reviewed, and 10 of them are selected as significant findings. Brief comments are given to each finding.
  • Articles
  • . 2007, 25(0703): 18-21.
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    The area to the north of Qilian Mountain is one of the most important areas in northwest China. Recently, the eco-environment in this area has drastically degradated and Ejina Banner has been turned from an ecological barrier into one of the sources of sandstorm. On the basis of quantitative remote sensing results, this paper studies the variation trend of NDVI from 1982 to 2002 in the area to the north of Qilian Mountain by using GIMMS NDVI data. It is shown that the variation trend of secular NDVI is rising in Jiuquan, Zhangye, Wuwei and Jinchang basins. On the other hand, the variation trend of secular NDVI in Ejina Banner, which is located in the downstream of Heihe River, is declining and the oasis is shrinking. The mechanism of oasis degradation is also analyzed in this paper.
  • . 2007, 25(0703): 22-27.
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    A high-resolution palaeoclimate record of recent 2 ka is obtained based on RRb/Sr and AMS 14C dating of Core DD2, which is located at the north of the mud area on the inner shelf of the East China Sea (ECS). 10 periods of low RRb/Sr are identified, which well agree with periods of lower temperature in China's history, and the lower temperature during about 990 AD is verified. According to the variation of RRb/Sr, the Sui-Tang dynasty Warming Period defined by Zhu Kezhen is confirmed on the whole, during which period a fluctuation of warm-cold-warm exists, and the cold period is during 800-890 AD. The Little Ice Age (LIA) extends from 1480 AD to 1890 AD, where 1520 AD, 1670 AD, 1780 AD and 1850 AD are cold.
  • . 2007, 25(0703): 28-33.
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    The study analyzed the effects of postovulatory aging of mouse oocytes, both in vivo and in vitro, on the development of mouse somatic cell nuclear transfer embryos in vitro. Oocytes were collected from female B6D2F1 mice 13, 15, 17, 20 hours after hCG injection, respectively. Nuclear transfer micromanipulation was completed within one hour, and the reconstructed embryos were activated after one hour. At the same time, the parthenogenesis development was compared. For in vitro aging experiment, all oocytes were collected 13 hours after hCG injection,then nuclear transfer was performed 13, 15, 17, 20 hours after hCG injection. The results showed that the postovulatory aging of oocytes both in vivo and in vitro affected the development of the cloned embryos in vitro. The cloned blastocyst rate reached the highest when oocytes were collected 13 hours after hCG injection and being micromanipulated at once. The cloned blastocyst rate significantly decreased when oocytes were collected 17 hours after hCG injection and when oocytes were collected 13 hours after hCG injection and being micromanipulated 20 hours after hCG injection. These results provide us with some practicable nuclear transfer procedure rules for cloning to achieve better results and reduce the error by manipulation when nuclear transfer is used in the fundamental researches.
  • . 2007, 25(0703): 34-38.
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    Preliminary studies were carried out on the effects of space environments on the expression of proteins and genes of melanoma B16 cells. Four B16 cells which were on board of China's 20th recoverable satellite were selected whose biological characteristics had changed obviously in the experiments in vitro, in order to detect changes of cells' expression of proteins and genes. B16 cells selected were inoculated into C57BL/6 mice under the chest skin. The tumor mice were killed when space cells had been inoculated for 2 weeks, then, tumors of tumor mice were ablated. To detect the expression of Melan-A(Melanoma Antigen Recognized by T cells 1, MART-1) and Vascular Endothelial Growth Factor(VEGF) in the carcinomas of tumor mice, the method of Immunohistochemistry (IH) was used. According to the above results, the space B16 cells were chosen, whose biological characteristics changed obviously and the expression variations of melan-a, gp100, bcl-2-associated anthanogene-3(bag-3) and Lipocalin-type Prostaglandin D2 synthase (l-pgds) were determined with the method of Reverse Transcription Polymerase Chain Reaction (RT-PCR). It was found that space environments might change the expression of proteins and genes of melanoma B16 cells.
  • . 2007, 25(0703): 39-44.
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    The hydroelectric development in the upper basin of the Yangtze River will greatly promote the development of navigation. Based on the analysis of current status and the existing problems of the navigation, the opportunity and challenge of the navigable channel constructions related to the hydroelectric development is analyzed, and our strategy is proposed in this paper.
  • . 2007, 25(0703): 45-49.
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    The artificial neural network has been widely used in the forecast and prediction due to the development of its theorectical basis and computer technology. The basic principle of BP neural network is briefly introduced, and the applications of BP neural network to air pollution prediction in China are reviewed in detail. It is applied to predict SO2 concentration in Suzhou, and it is shown that BP neural network is easy to implement and gives quite accurate results, and that it can also be used to predict other air pollutants such as PM10, NOx, and so on.
  • 研究报告
  • . 2007, 25(0703): 50-55.
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    From the viewpoint of enterprise value analysis, the core competence of an enterprise can be revealed not only by its real assets, but also, and to a greater extent, by its intangible assets. The value structure of intangible assets contains ample information of enterprise core competence. Thus a method of evaluating enterprise core competence is proposed, based on analyzing and comparing the structures of intangible assets of similar enterprises. First, AHP is used to split the combined intangible assets of an enterprise into several items; based on these items, DEA and multivariate analysis is used to evaluate the total status and the structure of core competence of each enterprise among a set of enterprises. A case study is carried out to show the application procedure of this method.
  • . 2007, 25(0703): 56-63.
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    Under the influence of adjustment of our economic policy and inflation, the Data Generating Process (DGP) of RMB real effective exchange rates may change its structure during the course of commercial activities in China. A co-integration-model of the equilibrium real exchange rate of RMB is proposed based on the structure changes of the DGP of RMB, and its validation is shown by analyzing the relation between the balance of payments and the maladjusted exchange rate. The result indicates that an obvious relationship exists between many fundamental variables and RMB real effective exchange rates, and the RMB real effective exchange rate has been under-valued in some degrees since 2002. The misalignment of exchange rate has a marked influence on the balance of payments in China.
  • . 2007, 25(0703): 64-69.
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    Since the beginning of reform and opening up to the outside world, the mechanism of controlling the income of urban residents in China has undergone a fundamental change. The income gap is widening among residents, and to some extent, the widening gap curbs the increase of consumption and hinders a further escalation of the consumption structure of urban residents, which affects the growth of consumers' demand. At present, the domestic market demand seriously hampers the development of national economy and constrains the economic growth rate. The consumption structure of urban residents relates directly to the consumption level, consumption characteristics and the trend of consumption development and to some extent determines the variations of all kinds of consumptions. In this paper, the Panel Data model is used to analyze the influence of urban residents' income distribution on their consumption structure and we have also discussed how to deal with insufficiency of domestic demand from the distribution aspect.
  • 科学家之声
  • . 2007, 25(0703): 70-73.
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    Groundwater plays an important role in domestic water supply for residents both in town and countryside, in social and economical development, and in the ecological equilibrium. Irrational exploitation of groundwater will cause groundwater overdraft, water quality pollution, and some other ecological and environmental issues. We must take measures to ensure sustainable exploitation and utilization of groundwater.
  • 学术争鸣
  • . 2007, 25(0703): 74-77.
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    In this paper, jerk function for a transient process of RL circuit is introduced, together with the comcepts of time rate of induced EMF, time rate of displacement current, and Appell function. The conservation of Appell function in LC oscillation circuits and simple harmonic vibrations is discussed。