共查询到20条相似文献，搜索用时 15 毫秒
1.
2.
《山地科学学报》2014,(1):F0003-F0003
The Journal of Mountain Science （JMS） is devoted to mountains and their surrounding lowlands - ecoregions of particular global importance, with a particular emphasis on the important highlands/ mountains in the world, such as the Tibetan Plateau, the Himalayas, the Alps, the Andes, the Rockies and many other mountain ranges of our planet. 相似文献
3.
The nitrogen(N) and phosphorus(P) budget and the ecological efficiency of a polyculture system of sea cucumber(Apostichopus japonicus), jellyfish(Rhopilema esculenta) and shrimp(Fenneropenaeus chinensis) were studied in a cofferdam, 120.2 ha in size. The nutrients were supplied by spring tide inflow. In total, 139600 kg N yr-1 and 9730 kg P yr-1 input to the system; while 118900 kg N yr-1 and 2840 kg P yr-1 outflowed from the system concurrently, thus the outflow was 85.7%(N) and 29.2%(P) of inflow. The production of N and P was 889.5 kg yr-1 and 49.28 kg yr-1(sea cucumber) and 204 kg yr-1 and 18.03 kg yr-1(jellyfish and shrimp), respectively. The utilization rate of N and P by polycultured animals was 7.8‰ and 6.9‰, respectively, 21.9% and 38% higher than that of monocultured sea cucumber. Our results indicated that the polyculture system was an efficient culture system of animals and a remediation system of coastal environment as well; it scavenged 14.3% and 70.8% of N and P, respectively. Such an ecological efficiency may be improved further by increasing either the stocking density or the size of sea cucumber or both. 相似文献
4.
Influences of large-scale climatic phenomena, such as the E1Nifio/La Nifia-Southem Oscillation （ENSO） and the Pacific Decadal Oscillation （PDO）, on the temporal variations of the annual water discharge at the Lijin station in the Huanghe （Yellow） River and at the Datong station in the Changjiang （Yangtze） River were examined. Using the empirical mode decomposition-maximum entropy spectral analysis （EMD- MESA） method, the 2- to 3-year, 8- to 14-year, and 23-year cyclical variations of the annual water discharge at the two stations were discovered. Based on the analysis results, the hydrological time series on the inter- annual to interdecadal scales were constructed. The results indicate that from 1950 to 2011, a significant downward trend occurred in the natural annual water discharge in Huanghe River. However, the changes in water discharge in Changjiang River basin exhibited a slightly upward trend. It indicated that the changes in the river discharge in the Huanghe basin were driven primarily by precipitation. Other factors, such as the precipitation over the Changjiang River tributaries, ice melt and evaporation contributed much more to the increase in the Changjiang River basin. Especially, the impacts of the inter-annual and inter-decadal climate oscillations such as ENSO and PDO could change the long-term patterns of precipitation over the basins of the two major rivers. Generally, low amounts of basin-wide precipitation on interannual to interdecadal scales over the two rivers corresponded to most of the warm ENSO events and the warm phases of the PDO, and vice versa. The positive phases of the PDO and ENSO could lead to reduced precipitation and consequently affect the long-term scale water discharges at the two rivers. 相似文献
5.
Allelic variation in a total of 7 microsatellites was examined between elvers of freshwater eels （Anguillajaponica and Anguilla anguilla）. The number of alleles at these loci ranged from 8 to 26. A single test of each locus revealed significant deficits of heterozygotes （P〈0.01）. Significant departure from expectations of Hardy-Weinberg equilibrium （HWE） was found for all loci within four subpopulations of A. japonica, which opposes the panmixia hypothesis of Schmidt. Also exact tests of population differentiation based on allelic frequency distribution disagree the hypothesis of random distribution of individuals among populations. Population structure among four populations of A. japonica was revealed with FST value of 0.009 8 （P=-0.000 48; 10 000 iteration）. Pairwise matrixes of FST and RST showed a significant difference between two distantly related species-A, japonica and A. anguilla. Divergent time of the two species calculated by Goldstein method is over 2 million years. The results may challenge the Schmidt＇s theory about the distribution of freshwater eels. 相似文献
6.
Polychlorinated dibenzo-p-dioxins （PCDDs） and dibenzofurans （PCDFs） in surface sediment and bivalve from the Changjiang Estuary, China 总被引：1，自引：0，他引：1
Surface sediments and bivalves were collected from the Changjiang Estuary in December 2003 and November 2004, respectively. Polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) in these samples were measured with high-resolution chromatography (HRGC)/High Resolution Mass Spectrometer (HRMS). The concentrations of total PCDD/Fs and toxic equivalent (TEQ) were 169.83±119.63 and 0.81±0.36 pg/g dry weight (dw) in sediments, and 580.33±240.17 and 7.24±3.65 pg/g dw in bivalves. The homolog compositions of PCDD/Fs were similar among samples, the most abundant congener was octa-chlorinated dibenzo-p-dioxin (OCDD) and then octa-chlorinated dibenzofuran (OCDF) and 1,2,3,4,6,7,8-hepta-chlorinated dibenzo-p-dioxin (HpCDD). The herbicide pentachlorophenol (PCP) and sodium pentachlorophenol (Na-PCP) were proved the main source of PCDD/Fs in this area. 相似文献
7.
《山地科学学报》2014,(3):F0002-F0002
The Journal of Mountain Science （JMS） is devoted to mountains and their surrounding lowlands ecoregions of particular global importance, with a particular emphasis on the important highlands/ mountains in the wodd, such as the Tibetan Plateau, the Himalayas, the Alps, the Andes, the Rockies and many other mountain ranges of our planet. 相似文献
8.
9.
2．大禹疏壶口
壶口瀑布,是黄河干流中最壮观的瀑布,它以平均1000个流量（立方米/秒）的速度,从30多米的高处在这宽仅20多米的峡口中倾泻而下,激起50米高的水花,飞出彩虹,浪沫漂到下游100-200米岸上,给游人身上增添点点泥沫。 相似文献
10.
LIUDongyan AmyPickering SUNJun 《中国海洋大学学报(英文版)》2004,3(1):75-79
1 Introduction Inrecentyears ,eutrophicationhasbecomeaworld wideenvironmentalprobleminthecoastalarea.Aqua culturebecomesaseriouspollutionsourcelikesewagedischarge .Wasteproductsfromfishfarmsconsistma inlyofnitrogen ,phosphorusandcarbondioxide .Inpen bas… 相似文献
11.
在Ａｕ（Ⅲ）－Ｃｌ络合溶液和常温常压条件下，黄铁矿随时间（ｔ）变化对金吸附的动态实验表明：整个吸附过程明显分为两个阶段．前一个阶段是快速达到平衡的吸附过程，随着平衡的建立，金的沉淀速度迅速变小，随后即进入缓慢吸附阶段，溶液中金的浓度按指数函数关系衰减．不同粒度黄铁矿实验结果的横向比较显示，粒度越细，金的沉淀速度越快，沉淀金的总量也越多。 相似文献
12.
13.
本文研究了在ＨＣｌ介质中，Ｄ４０１（ＥＤＴＡ）螯合树脂对铂、钯的吸附性能。实验表明，在ｐＨ＝２～４范围内，树脂对钯有良好的吸附性能，饱和吸附量７０．５ｍｇＰｄ（Ⅱ）／ｇ—Ｒ。ＰＨ≥４时对铂不吸附；钯的负载柱可用［０．１ｍｏｌＴｕ（硫脲）＋０．５ｍｏｌＨＣｌ］／Ｌ混合液定量洗脱，洗脱率为９９．２％、获得了ｐＨ＝４盐酸溶液中树脂柱分离铂、钯的方法。 相似文献
14.
Jian Wang Huarong Guo Shicui Zhang Licheng Yin Bin Guo Shaojie Wang 《中国海洋大学学报(英文版)》2008,7(2):184-192
A full-length cDNA encoding translationally controlled tumor protein of marine flatfish turbot (Scophthalmus maximus), SmTCTP, was isolated with rapid amplification of cDNA Ends (RACE). SmTCTP consisted of a 5' untranslated region (UTR) of 84 bp, a 3' UTR of 451 bp and an open reading flame (ORF) of 513 bp, encoding a protein of 170 amino acid residues, which contained two signature sequences of TCTP family. The 5'UTR of SmTCTP started with a 5'-terminal oligopyrimidine tract (5'-TOP), a typical feature for translationaily controlled mRNAs. The deduced amino acid sequence of SmTCTP was similar to the other known verte-brate TCTPs in a range of 58.8% to 64.1%. The length offish TCTPs was diverse among species, e.g., TCTP of turbot and sea perch (Lateolabrax japonicus) is 170 aa in length, while that of zebrafish (Danio rer/o) and rohu (Labeo rohita) is 171 aa in length. North-ern blot analysis revealed that SmTCTP has only one type of mRNA. Its expression level in albino skin was slightly higher than that in normal skin. We constructed the pET3Oa-SmTCTP expression plasmid. The recombinant protein of His-tag SmTCTP was over-expressed in E. coli, purified and identified with peptide mass fingerprinting. These results may pave the way of further inves-tigation of the biological function of TCTP in fish. 相似文献
15.
Use of Otolith Shape for the Identification of Trumpeter Sillago （Sillago maculata） and Silver Sillago （Sillago sihama） 总被引：1，自引：0，他引：1
Otolith shape is species-specific in fish. In this study, 161 samples of Trumpeter sillago Sillago maculata and 164 of Silver sillago Sillago sihama were collected from Beibu Gulf in July 2009. The main objective of this study was to use morphological variables and Fourier harmonics to describe otolith characteristics and use discriminant analyses to separate the two species. Otoliths were measured by traditional one and two dimensional measures(otolith length, width, diameters, area, perimeter, rectangularity and circularity), as well as by Fourier analysis to capture the finer regions of the otolith. Analysis of covariance(ANCOVA)showed that there was significant correlation between morphological variables(diameter, perimeter, otolith length, otolith width, otolith area, density, harmonics 3, harmonics 4, harmonics 5, harmonics 13, harmonics 15, and harmonics 16)and body length. To minimize size effects on the morphological variables between species, only fish with a body length between 90 and 140 mm were included in the data analysis and the variables which had significant relation with body length were transformed using the residual. The result showed that the accuracy of discriminant analysis was 97. 8% and 100% for Trumpeter sillago and Silver sillago, respectively. This high accuracy indicated that otolith shape was described accurately by morphological variables and Fourier harmonics, and discriminant analysis was an effective way to identify and separate the two species. 相似文献
16.
Concentrations of Cr, Co, Ni, Cu, Ga, Ge, As, Sb, W, Re, Ir, Pt and Au of two ungrouped iron meteorites, Grove Mountains （GRV） 98003 from Antarctica and Ujimqin, were measured using instrumental neutron activation analysis. According to the bulk chemistry, GRV 98003 is classified as a member of ⅠAB group, and Ujimqin as a unique one of ⅠAB iron meteorite complex. The elemental abundance pattern and correlation between elements （e. g. Ni-Au, Co-Au, As-Au, W- Au, Cu-Au, Sb-Au） of GRV 98003 are similar with those of NAW 468 （ⅠAB）, but significantly depleted in refractory siderophile elements （ Re, It） and moderate volatile elements （Ca, Ge） relative to the latter. In addition, we reclassify Nantan （ⅢCD） as a member of ⅠAB main group （MG） and Yongning （ⅠA） as a unique iron meteorite related with IAB iron meteorite complex. 相似文献
17.
秦健秋 《成都信息工程学院学报》2007,22(6):750-753
设k∈N，f（z）为复平面上的超越亚纯函数，φ（z）、ak-1（z），…，a0（z）为f（z）的小函数，且φ（z）≠0．置P（f）（z）=f^（k）（z）＋ak-1（z），f^（k-1）（z）＋…＋a1（z）f（z）＋a0，（z），且P（f）（z）不恒为常数．当k≤4时，满足Nr）（r，1/f）=S（r，f）；k≥5，满足N4）（r，1/f）=S（r，f），则T（r，f）〈20N^-（r，1/φfP-1）＋s（r，f）． 相似文献
18.
Soil types, humus types and vegetation as well as their hypsometric variation were analysed in terms of sequences in the northern part of the high mountains of the Pirin National Park at altitudes between looo and 2400 m a.s.1. The study area is characterised by a large variety of natural parameters like petrology （mainly marble and granite）, morphology （different slope deposits, exposition） and the orographic climate gradient. Statistical analyses using these parameters provided a basis for the soil group classification of the sites. Based on a Digital Terrain Model （DTM） and a geological map of the Pirin National Park, the results of these statistical analyses were used to generate a ＂map of potential soil groups＂ （regionalisation using GIS）. Six potential soil groups could be determined. The resulting map exhibits a confidence level of 68 % on 74.4 % of the covered area. Rendzic Leptosols, in combination with Folic Histosols and Histi-lithic Leptosols occur in the alpine and subalpine regions on calcareous substrates. With decreasing altitude they are replaced by a mosaic of Rendzic Leptosols, Phaeozems and an increasing occurrence of Cambic Umbrisols. Umbrisols found on silicatic substrates in the alpine region are replaced by Cambic Umbrisols with decreasing altitude as well. Hence, pedogenesis is characterised by increasing browning and depth of the soil profiles with decreasing altitude. The pH-level is slightly acidic to neutral in lower zones and on calcareous rocky bases. Acidification increases in the subalpine zone. Soil pH decreases down to 4 on silicate subtrates. Typical humic values in mineral topsoils are 10 to 12 %, and in organic layers of the soils above 2000 m a.s.1, they are even more. The C：N ratio closely ranges around 20 （median）. 相似文献
19.