EFFECTS OF FISH OIL,DHA OIL AND LECITIHIN IN MICROPARTICULATE DIETS ON STRESS TOLERANCE OF LARVAL GILTHEAD SEABREAM（SPARUS AURATA）     

刘镜恪王文琪  李岿然雷霁霖 《中国海洋湖沼学报》2002,20(4):338-343

The effects of natural fish oil,DHA oil and soybean lecithin in microparticulate diets on stress tolerance of larval gilthead seabream(Sparus aurata)were investigated after 15 days feeding trials.The tolerance of larval gilthead seabream to various stress factors such as exposure to air(lack of dissolved oxygen),changes in water temperature(low)and salinity(high) were determined.This study showed that microparticulate diet with natural fish oil and soybean lecithin was the most effective for in-creasing the tolerance of larval gilthead seabream to various stresses,and that microparticulate diet with natural fish oil and palmitic acid(16:0)was more effective than microparticulate diet with DHA oil and soybean lecithin.  相似文献   

AN ILLUSTRATIVE STUDY ON LOCAL LANDSCAPEAND ITS LONG-TERM CHANGES BASED ON IKONOS AND HISTORICAL AERIAL PHOTO   总被引：2，自引：0，他引：2  

RUANRen-zong ErieCELLISt 《中国地理科学(英文版)》2004,14(2):162-169

Nowadays, the research works on landscape at fine scales using high-resolution images are uncommon.This research is based on the analysis of the combination of remote sensing data (1KONOS imagery acquired in 2002 and historical aerial photo taken in 1942). In the paper, the ecotopes in Qiujiadou and Xishao villages in Yixing City of Jiangsu Province in 1942 and 2002 were compared and landscape changes as well as the causes of the considerable changes were analyzed. It was found that the ecotope changes were at greater level in some aspects such as water surface and perennial vegetation coverage etc. This study at fine scale is globally significant for the rural areas, especially for the subsistence agricultural land, which occupies larger percentage in the earth. And it analyzes the structure of landscape based on a new landscape classification system--stratifications method.  相似文献   

Preliminary investigation of mercury in bone tissues of skua and penguin in Antarctica using AFS and Synchrotron Radiation X-ray Fluorescence （SR-XRF）   总被引：1，自引：0，他引：1  

谢周清程邦波  孙立广黄宇营 何伟 《极地研究(英文版)》2005,16(1):33-40

Mercury （Hg） was investigated in bone tissues of skua （ Catharacta maccormick） and penguin （Pygoscelis adeliae） collected in the maritime Antarctic using atomic fluorescence spectrometry （AFS） and synchrotron radiation X-ray fluorescence （SR-XRF） method. The total levels of mercury in bone tissues of penguin and skua are much lower than those in other organs （e. g. , kidney, liver）. The toxic effects of mercury in bone tissues of seabirds in polar region are not known. We have used SR- XRF method to map the distribution of trace levels of mercury in bones. The levels of mercury are found to be enriched somewhere near the periosteal surface and/or endosteal surface. The distribution of mercury shows strongly correlation with that of some essential elements and probably poses negative effect on the bone metabolism inferring from the relationship of mercury with the other elements. These studies represent a first step toward understanding the toxic effects of mercury on bone of polar animals by suggesting the possible microscopic investigation.  相似文献   

Multi-wavelength Diagnostics of Bombardment by Non-thermal Particles in Solar Flares     

Zhi Xu  Cheng Fang  Wei-Qun Can Astronomy Department of Nanjing University  Nanjing  Purple Mountain Observatory  Chinese Academy of Sciences  Nanjing 《中国天文和天体物理学报》2005,5(5):519-530

Chromospheric lines, including Ha, Lyα, Lyβand CaⅡK, CaⅡ8542, are systemically and quantitatively investigated with respect to the non-thermal excitation and ionization due to particle beam bombardment for a series of solar semi-empirical atmospheric models. As a result we propose to use the contrast in the integrated intensity of hydrogen lines to estimate the total energy flux of the bombarding beam during the solar flare impulsive phase. Partial frequency redistribution is considered in the Lyαline calculation and a smaller intensity enhancement in the Ha line-centers is found than in the previous results of Fang et al.  相似文献   

Revisiting Sustainable Development of Dry Valleys in Hengduan Mountains Region   总被引：5，自引：1，他引：4  

TANGYa XIEJiasui SUNHui 《山地科学学报》2004,1(1):38-45

Dry valleys are a striking geographic landscape in Hengduan Mountains Region and are characterized by low rainfall, desert type of vegetation and fragile environment. Past efforts and resources have been concentrated mainly on rehabilitation of degraded ecosystem and fragile environment, particularly reforestation, while socio-economic development has been largely overlooked. Despite successes in pocket areas, the overall trend of unsustainability and environmental deterioration are continuing. It is important to understand that uplift of the Tibetan Plateau is the root cause of development of dry valleys, and development and formation of dry valleys is a natural process. Human intervention has played a secondary role in development of dry valleys and degradation of dry valleys though human intervention in many cases has speeded up environmental degradation of the dry valleys. It is important to understand that dry valleys are climatic enclaves and an integrated approach that combines rehabilitation of degraded ecosystems and socio-economic development should be adopted if the overall goal of sustainable development of dry valleys is to be achieved. Promotion of niche-based cash crops, rural energy including hydropower, solar energy, biogas and fuelwood plantation is recommended as the priority activities.  相似文献   

Research on the effect of sludge fertilizer on farmland and the safety of heavy metals in a karst area     

Qinglin Xie  Xuehong Zhang  Dunqiu Wang  Jincheng Li  Yiyong Qin  Yudao Chen 《Environmental Geology》2001,41(3-4):352-357

  相似文献   

AGGLOMERATION AND RADIATION EFFECT OF THE PULL OF URBANIZATION   总被引：2，自引：1，他引：1  

QIJin-li 《中国地理科学(英文版)》2003,13(3):224-227

In order to explore the train of thought for China‘s urbanizing development and coordinated rural eco-nomic development, and to find good ways of solving rural problems through urbanization, this paper absorbs the push-and-pull forces theory and the systematic dynamic theory in the traditional population migration theories, views urbanization as a dynamic system, makes research on the push-and-pull mechanism of urbanization. The pulling power of urbanization is analyzed according to two aspects, the agglomeration effect and the radiation effect of cities. The agglomeration effect provides continuous propelling force for urbanization, and the radiation effect further accelerates the urbanization process by pushing forward the development of rural economy. Of course, the slow de-velopment of urbanization can result in the hindrance to rural economic development.  相似文献   

Observational evidence for solar coronal decimetric radio pulsations with very short periods     

Xie Rui-xiang  Wang Min  Shi Shuo-biao  Xu Chun  Li Wei-hua  Yan Yi-hua 《Chinese Astronomy and Astrophysics》2003,27(4):426-434

Using the decimetric (700–1500 MHz) radio spectrometer and the synchronous observational system with high temporal resolution at four frequencies (1420, 2130, 2840 and 4260 MHz) of Yunnan Observatory, two rare events were observed on 2001 June 24 and 1990 July 30. The former was a small radio burst exhibiting pulsations with short periods (about 29, 40 and 100 ms) in the impulsive phase. The latter was a large radio burst, which at 2840 MHz produced radio pulsations with period of about 30 ms. This paper focuses on pulsations with very short periods in the range of 29–40 ms. The mechanism of generation of such pulsations may be modulation of radio radiation by the periodic trains of whistler packets originating in unstable regions of the corona. Alternatively, these pulsations can be attributed to wave-wave non-linear interactions of electrostatic upper hybrid waves driven by beams of precipitating electrons in flaring loops.  相似文献   

BRINGING FORWARD OF THE CONCEPT OF COGIS AND ITS ARCHITECUTRE RESEARCH     

HUXue-lian CHENGCheng-qi WUDe-wen MAAi-nai 《中国地理科学(英文版)》2003,13(1):84-90

Based on the analysis of the development of GIS technology and application,this paper brought forward the concept of GoGIS,namely Cooperative GIS ,CoGIS is GIS facing group-users and supporting human-human interaction,which makes it differ from the former GISs,Then,the characteristics of general Computer Spport Cooperative Work (CSCW)applications and the complexity of Geographic Information Science were analyzed,and the conclusion the CoGIS was not a simple GIS layer on CSCW was reached,Further,this paper gaver the hierarchical architecture of CoGIS,and analyzed the coperative platform in detail from the following:1)basic elements;2) collaboration patterns;3) cooperation control mechanism;4) synchronization mechanism;5) security and 6) group communication and so on.With those,the problems about GIS applications are discussed,such as 1)distributed multi-source GIS information and knowledge sharing platform;2)the fusion and visualization of GIS information;3)virtual reality cooperative modeling;4) dymamic simulation;5)expert system and 6) decision-making.Finally,this paper analyzed CoGIS application mode in brief.  相似文献   

Prediction Test for the Two Extremely Strong Solar Storms in October 2003   总被引：2，自引：0，他引：2  

Yanqiong Xie  Fengsi Wei  Xueshang Feng  Dingkun Zhong 《Solar physics》2006,234(2):363-377

In late October and early November 2003, a series of space weather hazard events erupted in solar-terrestrial space. Aiming at two intense storm (shock) events on 28 and 29 October, this paper presents a Two-Step method, which combines synoptic analysis of space weather–`observing’ and quantitative prediction – ‘palpating’, and uses it to test predictions. In the first step, ‘observing’, on the basis of observations of the source surface magnetic field, interplanetary scintillation (IPS) and ACE spacecraft, we find that the propagation of the shock waves is asymmetric and northward relative to the normal direction of their solar sources due to the large-scale configuration of the coronal magnetic fields, and the Earth is located near the direction of the fastest speed and greatest energy of the shocks. Being two fast ejection shock events, the fast explosion of extremely high temperature and strong magnetic field, and background solar wind velocity as high as 600 and 1000 km s⁻¹, are also helpful to their rapid propagation. According to the synoptic analysis, the shock travel times can be estimated as 21 and 20 h, which are close to the observational results of 19.97 and 19.63 h, respectively. In the second step, ‘palpating’, we adopt a new membership function of the fast shock events for the ISF method. The predicted results here show that for the onset time of the geomagnetic disturbance, the relative errors between the observational and the predicted results are 1.8 and 6.7%, which are consistent with the estimated results of the first step; and for the magnetic disturbance magnitude, the relative errors between the observational and the predicted results are 4.1 and 3.1%, respectively. Furthermore, the comparison among the predicted results of our Two-Step method with those of five other prevailing methods shows that the Two-Step method is advantageous in predicting such strong shock event. It can predict not only shock arrival time, but also the magnitude of magnetic disturbance. The results of the present paper tell us that understanding the physical features of shock propagation thoroughly is of great importance in improving the prediction efficiency.  相似文献