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   

Discovery of 13 New Variable Stars in the Field of the Open Cluster NGC 2168 （M35）     

Juei-Hwa Hu  Wing-Huen Ip 《中国天文和天体物理学报》2005,5(4):356-362

A wide-field time-series CCD photometric survey of variable stars in the field of the open cluster NGC 2168 was carried out using the BATC Schmidt telescope. In total 13 new variable stars are discovered with three W UMa systems, one EA type and two EB type eclipsing binaries (one of them could be a W UMa system), and seven pulsating stars including three candidates of δScuti stars.  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   

双酶法制备低黏度辛烯基琥珀酸淀粉钠的工艺条件   总被引：4，自引：0，他引：4  

阳元娥  罗发兴  黄强  谭伟 《广东海洋大学学报》2004,24(4):49-53

对双酶法制备用作微胶囊壁材的低黏度辛烯基琥珀酸淀粉钠的工艺路线与工艺条件进行了研究。正交实验结果表明 ,在酯化淀粉乳质量浓度 2 0 %、每 g淀粉α 淀粉酶的用量为 6SKBU的条件下 ,影响产品性能的各因素中 ,糖化酶的用量对产品的DE值和流度的影响最大 ,各因素的重要性依次是 :糖化酶的用量、糖化酶作用时间、α 淀粉酶保温作用时间。最佳工艺条件是 :α 淀粉酶保温作用时间 4min ,每 g淀粉糖化酶用量 0 .2GAU ,糖化酶作用时间 2 .5h ,此时产品的DE值为 30 ,流度为 80左右  相似文献   

A numerical model for Type II supernovae — The collapse stage     

Cong Xu  Zong-wei Li  Yun-zao Ge 《Chinese Astronomy and Astrophysics》1985,9(2):154-158

We use the following numerical model for the collapse stage of a Type II supernova of 15 M_⊙. Our electron capture rate includes the effects of the inverse reaction and the neutron-proton mass difference. This decreases the electron density at the collapse stage and led to rather large values of the maximum inward velocity and of the corresponding mass (Umax = 3.06 × 10⁹cm/s, Mmax=0.76 M_⊙). These larger values are more favourable for the propagation of shock after the rebounce and the triggering-off of a Type-II supernova explosion. For neutrino transport, we use a leakage model and an equilibrium diffusion model, respectively, for the thin and thick stages and a grey atmosphere model to assess the effect of neutrino precipitation on the collapse. We found this effect to be small, the energy precipitation to be not more than 10^?5 the neutrino energy loss and the momentum precipitation not more than 10^?6 the gravitational acceleration.  相似文献   

利用MapObjects的空间分析功能判断空间线面拓扑关系     

赵伟  邹峥嵘  余加勇 《测绘科学》2009,34(1)

MapObjects是广泛应用于GIS软件开发的组件,但它不能够独立支持空间拓扑关系,从而限制了它在空间分析方面的应用。为拓展MapObjects的空间分析功能,本文利用它提供的对图形对象的操作方法,实现了对九交模型中的空间线面拓扑关系的判断,且结果表明本文的实现方法正确可靠,具有一定的实用价值。  相似文献   

A study on the reference frame consistency in recent Earth gravitational models   总被引：1，自引：1，他引：0  

Christopher Kotsakis 《Journal of Geodesy》2009,83(1):31-50

All gravity field functionals obtained from an Earth gravitational model (EGM) depend on the underlying terrestrial reference frame (TRF), with respect to which the EGM’s spherical harmonic coefficients refer to. In order to maintain a coherent framework for the comparison of current and future EGMs, it is thus important to investigate the consistency of their inherent TRFs, especially when their use is intended for high precision studies. Following the methodology described in an earlier paper by Kleusberg (1980), the similarity transformation parameters between the associated reference frames for several EGMs (including the most recent CHAMP/GRACE models at the time of writing this paper) are estimated in the present study. Specifically, the differences between the spherical harmonic coefficients for various pairs of EGMs are parameterized through a 3D-similarity spatial transformation model that relates their underlying TRFs. From the least-squares adjustment of such a parametric model, the origin, orientation and scale stability between the EGMs’ reference frames can be identified by estimating their corresponding translation, rotation and scale factor parameters. Various aspects of the estimation procedure and its results are highlighted in the paper, including data weighting schemes, the sensitivity of the results with respect to the selected harmonic spectral band, the correlation structure and precision level of the estimated transformation parameters, the effect of the estimated differences of the EGMs’ reference frames on their height anomaly signal, and the overall feasibility of Kleusberg’s formulae for the assessment of TRF inconsistencies among global geopotential models.  相似文献