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大黄游离蒽醌致泻作用机制研究 被引量:17
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作者 罗培 徐象珍 谭正怀 《中药药理与临床》 CAS CSCD 北大核心 2013年第3期88-90,共3页
目的:评价两种一氧化氮合酶抑制剂对大黄游离蒽醌致大鼠腹泻作用的影响,以探讨大黄泻下作用相关机制。方法:应用实验大鼠在体肠道单向灌流模型,分别考察正常对照组、大黄游离蒽醌低剂量组、大黄游离蒽醌高剂量组、大黄游离蒽醌高剂量联... 目的:评价两种一氧化氮合酶抑制剂对大黄游离蒽醌致大鼠腹泻作用的影响,以探讨大黄泻下作用相关机制。方法:应用实验大鼠在体肠道单向灌流模型,分别考察正常对照组、大黄游离蒽醌低剂量组、大黄游离蒽醌高剂量组、大黄游离蒽醌高剂量联用L-NAME组及大黄游离蒽醌高剂量联用地塞米松组的致泻作用。通过记录灌入量和流出量,测量灌流肠段的表面积,检测流出液的总蛋白、葡萄糖以及Na+、K+及Cl-含量进行评估。结果:大黄游离蒽醌10μg/ml在体灌流能显著提高大鼠肠道流出液的蛋白质浓度、钠以及氯离子浓度;L-NAME10μg/ml和地塞米松5μg/ml均可显着对抗这种作用,与大黄游离蒽醌10μg/ml有统计学差异。在体灌流大黄游离蒽醌2μg/ml和大黄游离蒽醌10μg/ml均有增加流出液的量以及减少葡萄糖吸收的趋势,但与正常对照组比较没有显着差异。结论:大黄游离蒽醌致腹泻作用与其抑制一氧化氮合酶特别是诱导型一氧化氮合酶的活性有关,其详细作用机制有待进一步深入研究。 展开更多
关键词 黄游离蒽醌 腹泻 一氧化氮合酶 诱导型一氧化氮合酶
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大黄游离蒽醌对重症急性胰腺炎大鼠肾损伤的影响 被引量:9
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作者 王璐璐 刘媛琪 +2 位作者 陈立 范玲 熊玉霞 《中药药理与临床》 CAS CSCD 北大核心 2015年第2期31-34,共4页
目的:探讨重症急性胰腺炎对肾脏的影响,并观察大黄游离蒽醌对肾脏的保护作用。方法:雄性大鼠72只,随机分为假手术对照组、重症急性胰腺炎模型组、生大黄水煎液干预组和大黄游离蒽醌干预组4个组,生大黄组和大黄游离蒽醌组在胰腺炎建模前... 目的:探讨重症急性胰腺炎对肾脏的影响,并观察大黄游离蒽醌对肾脏的保护作用。方法:雄性大鼠72只,随机分为假手术对照组、重症急性胰腺炎模型组、生大黄水煎液干预组和大黄游离蒽醌干预组4个组,生大黄组和大黄游离蒽醌组在胰腺炎建模前12h和建模后2h分别给予生大黄水煎液和大黄游离蒽醌灌胃。各组分别于术后6h、12h和24h后三个时间点处死大鼠取肾脏组织,HE染色法观察肾脏组织的病理组织学改变,酶联免疫吸附法测定肾脏组织匀浆中肿瘤坏死因子-α(TNF-α)和白细胞介素-1(IL-1)水平,髓过氧化物酶法检测肾脏组织匀浆髓过氧化物酶(MPO)活性。结果:胰腺炎模型组与假手术组相比三个时间点TNF-α(0.358±0.016 vs 0.190±0.005 P<0.05;0.390±0.010 vs 0.204±0.005 P<0.05;0.396±0.005 vs 0.198±0.003 P<0.05)和IL-1(0.334±0.004 vs 0.179±0.004 P<0.05;0.342±0.005 vs 0.176±0.003P<0.05;0.365±0.005 vs 0.174±0.004P<0.05)水平,以及肾组织MPO酶活性(0.860±0.014 vs 0.539±0.009 P<0.05;0.867±0.010 vs 0.610±0.005 P<0.05;0.870±0.013 vs 0.545±0.009 P<0.05)均明显升高,差异有显著性。生大黄组和大黄游离蒽醌组与胰腺炎组相比较均显著抑制12h和24h肾组织TNF-α(0.286±0.008 vs 0.390±0.010 P<0.05;0.295±0.008 vs 0.396±0.005 P<0.05)和IL-1(0.254±0.005 vs 0.342±0.005 P<0.05;0.267±0.004 vs 0.365±0.005 P<0.05)水平,显著抑制6h和12h肾组织MPO酶活性(0.730±0.008 vs 0.860±0.014 P<0.05;0.730±0.010 vs 0.867±0.010 P<0.05);生大黄组和大黄游离蒽醌组之间的差异无显著性。结论:大黄水煎液和大黄游离蒽醌均能抑制胰腺炎时机体的炎症反应从而减轻对肾脏的损伤作用,大黄游离蒽醌与大黄水煎液的疗效相当。 展开更多
关键词 大黄 游离蒽醌 急性胰腺炎 肾脏损伤 细胞因子
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Vegetation Influence Investigation of GangnanHuangbizhuang Reservoir Downstream River and Recovery Strategies
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作者 张茹春 郑振华 +1 位作者 崔建军 张韬 《Agricultural Science & Technology》 CAS 2015年第11期2552-2554,共3页
The research selected three typical areas for plant investigation, including upper reaches of Gangnan Reservoir, the area between Gangnan and downstream of Huangbizhuang Reservoir, and Huangbizhuang Reservoir. The res... The research selected three typical areas for plant investigation, including upper reaches of Gangnan Reservoir, the area between Gangnan and downstream of Huangbizhuang Reservoir, and Huangbizhuang Reservoir. The results showed that affected by water, plant species, species diversity and species richness were all decreasing in varying degrees as the distance with watercourse upper reaches was increasing, but the ratio of Anthropochory plants was growing. The research finally proposed countermeasures, including increasing wetland area, constructing forests and artificial water landscape of Hutuo River and reinforcing watercourse compre- hensive management. 展开更多
关键词 The reservoir downstream river VEGETATION Gangnan-Huangbizhuangreservoir Vegetation restoration
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Adaptation Management of Mountain Tourism Service: The Case of the Source Regions of the Yangtze and Yellow River 被引量:6
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作者 FANG Yiping QIN Dahe +1 位作者 DING Yongjian YANG Jianping 《Journal of Mountain Science》 SCIE CSCD 2009年第3期299-310,共12页
Mountain areas are often rich in ecological diversity and recreational opportunities. Mountain tourism is thought to be an effective and important means for maintaining and expanding rural economies and, thus, improvi... Mountain areas are often rich in ecological diversity and recreational opportunities. Mountain tourism is thought to be an effective and important means for maintaining and expanding rural economies and, thus, improving the living conditions of rural societies. As mountain tourism service research is a professional field with several disciplines involved, a multi-disciplinary management pIatform is needed and it facilitates participation in sustainable mountain development by diverse stakeholders. With the source regions of the Yangtze and the Yellow River as a case study, this paper presents a conceptual framework for an adaptation management of mountain tourism services according to technical, policy, social and economic dimensions. The framework is based on a vulnerability assessment of mountain ecosystems, and can serve as a reference for the development of tourism service in other mountain areas. 展开更多
关键词 adaptation management mountain tourism service (MTS) source regions of Yangtze and Yellow Rivers China
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Using Landsat TM Imagery to Detect Desertification in Gonghe Basin at the Upper Reaches of the Yellow River 被引量:1
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作者 XU Huo ZENG Yong-nian 《Journal of China University of Mining and Technology》 EI 2006年第3期287-291,共5页
In recent years, the ecological environment in the upper reaches of the Yellow River has been degraded due to natural and human factors. Environmental problems such as grassland degeneration, sandy desertification and... In recent years, the ecological environment in the upper reaches of the Yellow River has been degraded due to natural and human factors. Environmental problems such as grassland degeneration, sandy desertification and water erosion have seriously affected regional economic sustainable development. The objective of this paper was to detect sandy desertification in the upper reaches of the Yellow River by means of remote sensing and GIS. The Gonghe Basin was chosen as the study site, which is one of the most seriously degraded regions in the area. Based on an analysis of the multi-temporal and multi-spectral Landsat TM data with GIS, sandy desertification processes were detected. The results show that sandy desertified land has increased and intensified seriously in the upper reaches of the Yellow River for the period from 1987 to 1996. There are two desertification processes at work in the study area: sand dune reactivation and development of badlands through wind erosion. Excessive human activities play an important role in the occurrence and development of desertification in this area. At present, acceleration of the desertification process is attributed to irrational human economic activities. Grasslands as well as the ecological environment of this area have been seriously degraded, which has affected the regional economic sustainable development and endangered the security of the Longyangxia reservoir. It is necessary and urgent to combat desertification and protect the environment. The results show that full use of remote sensing data with GIS in monitoring and assessing desertification is an effective measure of quantitative research. 展开更多
关键词 sandy desertification detection remote sensing GIS Gonghe Basin
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Seasonal Variations of Net-Phytoplankton Community Structure in the Southern Yellow Sea 被引量:10
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作者 GAO Yu JIANG Zhibing +3 位作者 LIU Jingjing CHEN Quanzhen ZENG Jiangning HUANG Wei 《Journal of Ocean University of China》 SCIE CAS 2013年第4期557-567,共11页
Based on the field survey data of four cruises in 2011,all phytoplankton communities in the southern Yellow Sea (SYS) were investigated for the species composition,dominant species,abundance and diversity indices.A to... Based on the field survey data of four cruises in 2011,all phytoplankton communities in the southern Yellow Sea (SYS) were investigated for the species composition,dominant species,abundance and diversity indices.A total of 379 species belonging to9 phyla were identified,of which the most abundant group was Bacillariophyta (60.9%) ,followed by Pyrrophyta (23.7%) and Haptophyta (6.9%) .The seasonal distribution of abundance was:summer (4137.1×103ind m 3) >spring (3940.4×103ind m 3) >winter (3010.6×103ind m 3) >autumn (340.8×103ind m 3) ,while the horizontal distribution showed a decreasing tendency from inshore to offshore regions.The dominant species of phytoplankton varied in different seasons.The dominant species were Thalassiosira pacifica,Skeletoema spp.and Chaetoceros cinctus in spring,Chaetoceros debbilis,Chaetoceros pseudocurvisetus and Chaetoceros curvisetus in summer,Thalassiosira curviseriata,Alexandrium catenella and Ceratium fusus in autumn,Paralia sulcata,Phaeocystis sp.and Bacillaria paradoxa in winter,respectively.In SYS,the group of temperate coastal species was the major ecotype,and the groups of the central SYS species and oceanic species were also important constituents.The average values of Shannon-Weaver diversity index (H’) and Pielou evenness index (J) were 2.37 and 0.65 respectively.The indices H’and J in the open sea were higher than those in coastal waters.Obvious co-variation tendencies between H’and J were observed in all but the summer cruise of this survey. 展开更多
关键词 PHYTOPLANKTON community structure DIVERSITY temperature SALINITY Southern Yellow Sea
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PUSH-PULL FACTORS IN MOUNTAIN RESORTS——A Case Study of Huangshan Mountain as World Heritage 被引量:3
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作者 WANGDe-gen 《Chinese Geographical Science》 SCIE CSCD 2004年第4期368-376,共9页
The push-pull framework provides a useful approach for examining the tourist motivation. This paper takes the world heritage-Huangshan Mountain as a sample. From the two different aspects of pull and push factors, the... The push-pull framework provides a useful approach for examining the tourist motivation. This paper takes the world heritage-Huangshan Mountain as a sample. From the two different aspects of pull and push factors, the underlying features of visitors′ motives to Huangshan Mountain are analyzed with the help of factor analysis. As a result, five push factors and four pull factors are identified. Further analyses investigate differences in the push and pull factors among different socio-demographic subgroups with one-way ANOVA analysis. The result of the study affords us useful references for development, protection and marketing expansion of mountain resorts. 展开更多
关键词 push factors pull factors socio-demographic characteristics Huangshan Mountain
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Study on distributional characteristics of phytoplankton population in the Bohai Sea and the Yellow Sea in the summer 2015 被引量:1
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作者 ZHU Ze-min SUN De-yong +8 位作者 GUO Jun-ru FU Yan-zhao LI Yong-quan LI Shuai LI Ling-li GUO Xiao-fang SUI Wen-yan WANG Meng ZUO Wen-ting 《Marine Science Bulletin》 CAS 2019年第2期72-85,共14页
Marine phytoplankton plays a very important role in marine ecology,environment and global climate change,and it is an indicative organism for measuring water quality.The Bohai Sea and the Yellow Sea in China have uniq... Marine phytoplankton plays a very important role in marine ecology,environment and global climate change,and it is an indicative organism for measuring water quality.The Bohai Sea and the Yellow Sea in China have unique geographical locations.Therefore,the characteristics of phytoplankton population distribution in the Bohai Sea and the Yellow Sea are of great significance to the study of marine ecology in China.In this work,the pigment data obtained from the Yellow Sea and Bohai Sea in August 2015 were analyzed by HPLC(High-Performance Liquid Chromatography).Then the pigment data were analyzed statistically by the CHEMTAX software,so that the phytoplankton community structure information was obtained.Results show that in summer 2015,from the perspective of sea area,the biomass of phytoplankton in the surface of Bohai Sea is higher than that in the Yellow Sea,while the phytoplankton biomass in the surface of North Yellow Sea is higher than that in the South.From the perspective of dominant species of phytoplankton,the surface waters of the Yellow Sea and Bohai Sea were dominated by diatoms,prymnesiophytes and chlorophytes,accounting for 55.76%,14.56%and 14.55%respectively.Among them,diatoms accounted for the absolute advantage. 展开更多
关键词 Bohai Sea and Yellow Sea PHYTOPLANKTON population distribution HPLC CHEMTAX PIGMENT
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Effect of Water and Sediment Regulation on Lower Yellow River 被引量:2
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作者 徐国宾 司春棣 《Transactions of Tianjin University》 EI CAS 2009年第2期113-120,共8页
According to the results of the water and sediment regulations of the Yellow River in year 2002—2007,the effect of erosion and deposition on the lower reaches,the amount and distribution of erosion and deposition in ... According to the results of the water and sediment regulations of the Yellow River in year 2002—2007,the effect of erosion and deposition on the lower reaches,the amount and distribution of erosion and deposition in the river mouth area,the adjustment of river regime,the effect of river regulation projects and changes of flowing capacity of the channel are analyzed.It is revealed that the water and sediment regulation is efficient to reduce deposition and improve the flowing capacity and the conditions of sediment transport. 展开更多
关键词 Yellow River water and sediment regulation river control sediment transport
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Mapping the Risk of Water Erosion in the Watershed of the Ningxia-Inner Mongolia Reach of the Yellow River, China 被引量:3
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作者 DU He-qiang XUE Xian WANG Tao 《Journal of Mountain Science》 SCIE CSCD 2015年第1期70-84,共15页
Mapping and assessing soil-erosion risk can address the likelihood of occurrence of erosion as well as its consequences. This in turn provides precautionary and relevant suggestions to assist in disaster reduction. Be... Mapping and assessing soil-erosion risk can address the likelihood of occurrence of erosion as well as its consequences. This in turn provides precautionary and relevant suggestions to assist in disaster reduction. Because soil erosion by water in the watershed of the Ningxia-Inner Mongolia reach of the Yellow River is closely related to silting of the upper reaches of the Yellow River, it is necessary to assess erosion risk in this watershed. This study aims to identify the soil-erosion risk caused by water in the watershed of the Ningxia-Inner Mongolia reach of the Yellow River from 2ool to aOlO. Empirical models called Chinese Soil Loss Equation (CSLE) and Modified Universal Soil Loss Equation (MUSLE) were used to predict the erosion modulus in slope surfaces and gullies. Then the soil erosion risk in this watershed was assessed according to the classification criteria of soil erosion intensities (SL19o-2oo7). The study results showed that the range of values of the erosion modulus in this watershed was o-44,733 t/km2/a. More than 20% of the total watershed area was found to present an erosion risk, with the regions at risk mainly located in channels and their upper reaches, and in mountainous areas. To determine the regression coefficients of the erosion factors with respect to erosion modulus, a GWR (geographically weighted regression) was carried out using the ArcGIS software. It was found that the topographic factor has the highest contribution rate to the soil erosion modulus, while the highest contribution rate of the erosion factors to the erosion modulus and the largest values of the factors were not located in the same places. Based on this result, the authors propose that slope management is the most important task in preventing soil loss in this watershed, and the soil- conservation projects should be built according to the eontribution rate of the erosion factors. 展开更多
关键词 Chinese Soil Loss Equation (CSLE) Erosion risk Geographically weighted regression(GWR) Yellow River
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Dust source of the Holocene loess-soil and pedogenic environmental changes in the upper Huaihe River 被引量:4
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作者 李新艳 黄春长 +1 位作者 庞奖励 何忠 《Journal of Geographical Sciences》 SCIE CSCD 2009年第1期107-117,共11页
Based on field surveys,soil samples were collected at the YPC site,Yuzhou City,Henan Province for analysis of contents of major and trace elements and their variations with XRF and comparison with the curves of magnet... Based on field surveys,soil samples were collected at the YPC site,Yuzhou City,Henan Province for analysis of contents of major and trace elements and their variations with XRF and comparison with the curves of magnetic susceptibility,pH value distribution,loss on ignition and particle-size distribution.It was concluded that the dust source of loess in the upper reaches of the Huaihe River Basin was different from that in the Loess Plateau.And the Holocene pedogenic environmental changes in the upper reaches of the Huaihe River Basin were revealed. 展开更多
关键词 LOESS PALAEOSOL HOLOCENE dust source upper reaches of the Huaihe River China
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Influence of Vegetation on Runoff and Sediment in Wind-water Erosion Crisscross Region in the Upper Yellow River of China 被引量:3
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作者 WANG Jinhua LI Zhanbin +1 位作者 YAO Wenyi DONG Guotao 《Chinese Geographical Science》 SCIE CSCD 2017年第4期569-576,共8页
All characteristics of vegetation,runoff and sediment from 1960 to 2010 in the Xiliu Gully Watershed,which is a representative watershed in wind-water erosion crisscross region in the upper reaches of the Yellow River... All characteristics of vegetation,runoff and sediment from 1960 to 2010 in the Xiliu Gully Watershed,which is a representative watershed in wind-water erosion crisscross region in the upper reaches of the Yellow River of China,have been analyzed in this study.Based on the remote sensing image data,and used multi-spectral interpretation method,the characteristics of vegetation variation in the Xiliu Gully Watershed have been analyzed.And the rules of precipitation,runoff and sediment's changes have been illuminated by using mathematical statistics method.What′s more,the influence mechanism of vegetation on runoff and sediment has been discussed by using the data obtained from artificial rainfall simulation test.The results showed that the main vegetation type was given priority to low coverage,and the area of the low vegetation coverage type was reducing year by year.On the country,the area of the high vegetation coverage type was gradually increasing.In a word,vegetation conditions had got better improved since 2000 when the watershed management project started.The average annual precipitation of the river basin also got slightly increase in 2000–2010.The average annual runoff reduced by 37.5%,and the average annual sediment reduced by 73.9% in the same period.The results of artificial rainfall simulation tests showed that the improvement of vegetation coverage could increase not only soil infiltration but also vegetation evapotranspiration,and then made the rainfall-induced runoff production decrease.Vegetation root system could increases the resistance ability of soil to erosion,and vegetation aboveground part could reduce raindrop kinetic energy and splash soil erosion.Therefore,with the increase of vegetation coverage,the rainfall-induced sediment could decrease. 展开更多
关键词 vegetation coverage runoff sediment infiltration rate wind-water erosion crisscross region
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Trends in Annual and Seasonal Pan Evaporation in the Lower Yellow River Basin from 1961 to 2010 被引量:7
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作者 JI Xing-Jie WANG Ji-Jun +2 位作者 GU Wan-Long ZHU Ye-Yu LI Feng-Xiu 《Advances in Climate Change Research》 SCIE 2012年第4期195-204,共10页
The annual and seasonal trends in pan evaporation in the lower Yellow River Basin based on quality-controlled data from 10 meteorological stations in 1961-2010 are analyzed. The causes for the changes in annual and se... The annual and seasonal trends in pan evaporation in the lower Yellow River Basin based on quality-controlled data from 10 meteorological stations in 1961-2010 are analyzed. The causes for the changes in annual and seasonal pan evaporation are also discussed. The results suggest that, despite the 1.15~C increasing in annual mean surface air temperature over the past 50 years (0.23°C per decade), the annual pan evaporation has steadily declined by an average rate of-7.65 mm per year. By comparison, this change is greater than those previously reported in China. Significant decreasing trends in annual pan evaporation have been observed at almost all stations. As a whole, seasonal pan evaporation decreased significantly, especially in summer, whereas seasonal temperature increased significantly, except in summer. Thus, the pan evaporation paradox exists in the lower Yellow River Basin. The trend analysis of other meteorological factors indicates significant decrease in sunshine duration and wind speed, but no significant variations in precipitation and relative humidity at annual and seasonal time scales. By examining the relationship between precipitation and pan evaporation, it did not show a concurrent decrease in pan evaporation and increase in precipitation. The partial correlation analysis discovered that the primary cause of decrease in annual and seasonal pan evaporation is the decrease in wind speed. A further examination using a stepwise regression shows that decrease in wind speed and sunshine duration, and increase in mean temperature axe likely to be the main meteorological factors affecting the annual and seasonal pan evaporation in the lower Yellow River Basin over the past 50 years. 展开更多
关键词 lower Yellow River Basin pan evaporation TREND meteorological factors
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Impact of microzooplankton and Calanus sinicus(Brodsky,1962) on phytoplankton in the Yellow Sea during early summer 被引量:1
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作者 于莹 张武昌 +3 位作者 肖天 李洪波 李超伦 孙松 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2010年第4期881-886,共6页
Dilution incubations and Calanus sinicus addition incubations were simultaneously conducted at five stations in the Yellow Sea in June of 2004 to evaluate the impact of microzooplankton and Calanus sinicus on phytopla... Dilution incubations and Calanus sinicus addition incubations were simultaneously conducted at five stations in the Yellow Sea in June of 2004 to evaluate the impact of microzooplankton and Calanus sinicus on phytoplankton based on the Chlorophyll a(Chl-a) levels.The Chl-a growth rates(k) ranged from 0.60-1.67 d-1,while microzooplankton grazed the Chl-a at rates(g) of 0.29-0.62 d-1.The addition of C.sinicus enhanced the Chl-a growth rate(Z) by 0.004-0.037 d-1 ind.-1 L.C.sinicus abundance ranged from 84.1-160.9 ind.m-3,which occupied 90.7%-99.1% of the copepod(>500 μm) population.The in-situ increase in phytoplankton by C.sinicus community was estimated to be 0.000 4-0.005 9 d-1.These results showed that microzooplankton were the main grazers of phytoplankton,while C.sinicus induced a slight increase in the levels of phytoplankton. 展开更多
关键词 Calanus sinicus copepod addition incubation dilution incubation MICROZOOPLANKTON the Yellow Sea
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Biomarker evidence for paleoenvironmental changes in the southern Yellow Sea over the last 8200 years 被引量:4
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作者 XING Lei ZHAO Meixun +4 位作者 ZHANG Hailong ZHAO Xiaochen ZHAO Xiaohui YANG Zuosheng LIU Chuanlian 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2012年第1期1-11,共11页
Previous studies have indicated that the Yellow Sea underwent significant environmental changes during the Holocene, but many questions remain concerning the timing of the establishment of the modern circulation syste... Previous studies have indicated that the Yellow Sea underwent significant environmental changes during the Holocene, but many questions remain concerning the timing of the establishment of the modern circulation system, which would have major implications for the Yellow Sea ecosystem and carbon cycle. In this study, marine and terrestrial biomarkers were analyzed in Core YE-2 from a muddy area in the southern Yellow Sea to reconstruct Holocene environmental and phytoplankton community change. The content of three individual marine phytoplankton biomarkers (alkenones, brassicasterol and dinosterol) all display a similar trend, and their total contents during the early Holocene (362 ng/g) were lower than those during the mid-late Holocene (991 ng/g). On the other hand, the contents of terrestrial biomarkers (C27+C29+C31n-alkanes) during the early Holocene (1 661 ng/g) were about three times higher than those during the mid-late Holocene (499 ng/g). Our biomarker results suggest that the modern circulation system of the Yellow Sea was established by 5-6 ka, and resulted in higher marine productivity and lower terrestrial organic matter inputs. Biomarker ratios were used to estimate shifts in phytoplankton community structure in response to mid-Holocene (5-6 ka) environmental changes in the Yellow Sea, revealing a transition from a dinoflagellate-diatom dominant community structure during the early Holocene to a coccolithophore-dominant community structure during the mid-late Holocene. 展开更多
关键词 BIOMARKER Yellow Sea muddy area PALEOPRODUCTIVITY phytoplankton community structure
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ROLE OF INTERVENING OPPORTUNITY IN TOURIST DESTINATION DEVELOPMENT 被引量:1
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作者 PAN Li-li BAO Ji-gang 《Chinese Geographical Science》 SCIE CSCD 2005年第4期368-376,共9页
Intervening opportunity is an important factor in spatial interaction, and has very important impacts on tourist destination development in a region. There are few literatures on this topic in tourist researches, and ... Intervening opportunity is an important factor in spatial interaction, and has very important impacts on tourist destination development in a region. There are few literatures on this topic in tourist researches, and especially in China fewer tourist researchers pay attention to intervening opportunity theory. This article, taking Lin’an as a case study, aims to introduce intervening opportunity theory in tourist destination development by the comprehensive ana-lysis of some data including literatures, Internet information, longitudinal data and some tourist surveys. Both qualitative and quantitative methods are all used in this research. Firstly, the authors expatiate upon the definition of intervening opportunity, by reviewing the literatures in detail, take Lin’an of Zhejiang Province as a case study, and then analyze some necessary factors of intervening opportunity, such as regional tourist demands and supplies, tourist attractions, spatial distance and transportation, tourist images and costs, regional competition and cooperation in tourist destinations. Finally the impacts of intervening opportunity on Lin’an tourist development are analyzed in detail. The results show that intervening opportunity do not occur everywhere, and there must be some critical factors, and intervening opportunity surely plays important roles in tourist destination development. The tourist development in Lin’an is attributed to intervening opportunity of the spatial location between Hangzhou and Huangshan that are two famous tourist cities in China, and the occurrence of intervening opportunities in Lin’an is the integration of some external and internal factors. 展开更多
关键词 intervening opportunity theory spatial competition Lin'an Huangshan Hangzhou
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Distribution of nutrients and eutrophication assessment in the Bohai Sea of China 被引量:23
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作者 王修林 崔正国 +2 位作者 郭全 韩秀荣 王江涛 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2009年第1期177-183,共7页
Water samples were collected in 120 stations in the Bohai Sea of China to analyze the distribution of dissolved nutrients and assess the degree of eutrophication in August 2002. The result shows that the average conce... Water samples were collected in 120 stations in the Bohai Sea of China to analyze the distribution of dissolved nutrients and assess the degree of eutrophication in August 2002. The result shows that the average concentration of DIN increased and the PO4-P concentration sharply decreased compared to the previous data of corresponding period. The high concentrations of DIN and PO4-P occurred in coastal waters, especially in the bays and some river estuaries, while the high concentrations of SiO3-Si in the surface and middle depth occurred in the central area of the Bohai Sea. The average ratio of DIN/PO4-P was much higher than the Redfield Ratio (16:1). Apparently, PO4-P was one of the limiting nutrient for phytoplankton growing in the sea. The average concentrations of DON and DOP were higher than their inorganic forms. The results of eutrophication assessment show that 22.1% of all stations were classified as violating the concentration levels of the National Seawater Quality Standard (GB 3097-1997) for DIN and only 3.9% for PO4-R The average eutrophication index in the overall area was 0.21±0.22 and the high values occurred in Bohai Bay, Liaodong Bay and near the Yellow River estuary. This means that the state of eutrophication was generally mesotrophic in the Bohai Sea, but relatively worse in the bays, especially some river estuaries. 展开更多
关键词 eutrophication aassessment NUTRIENTS DISTRIBUTION Bohai Sea
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Response of the distributary channel of the Huanghe River estuary to water and sediment discharge regulation in 2007
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作者 马妍妍 李广雪 +6 位作者 叶思源 张志恒 赵广明 李景阳 周春艳 丁文洁 杨欣 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2010年第6期1362-1370,共9页
The water and sediment discharge regulation (WSDR) project, which has been performed since 2002 before flood season every year, is of great significance to the river management in China. Until 2007, six experiments ... The water and sediment discharge regulation (WSDR) project, which has been performed since 2002 before flood season every year, is of great significance to the river management in China. Until 2007, six experiments have been fulfilled to evaluate the effect of the project on the natural environment. To fill the gap of investigations, a study on flood and suspended sediment transportation and channel changing along the distributary channel of the Huanghe (Yellow) River was conducted during the WSDR project period in 2007. The lower channel was scoured rapidly and the channel became unobstructed gradually several days after the flood peak water was discharged from the Xiaolangdi Reservoir. Within four days after the flood peak at 3 000 m3/s entered the distributary, the channel in the river mouth area was eroded quickly. Both the mean values of area and depth of the main channel were tripled, and the maximum flood carrying capacity increased to 5 500 m3/s or more. Then, the river channel was silted anew in a very short time after completion of the WSDR. Favored by the WSDR project, the fiver status in April 2008 became better than that of the year before. The adjustment ranges of main channel parameters were about 30%, 10%, and 10% at sections C2, Q4, and Q7, respectively. The process of rapid erosion-deposition was more active 15 km away in the channel from the fiver mouth due to the marine influence. It is reasonable for discharging sediment at concentration peak from Xiaolangdi Reservoir at the end of the flood peak. As a result, the sediment peak reached the river mouth about two days later than that of the water current. In addition, the WSDR project has improved the development of the estuarine wetland. Wetland vegetation planted along the river banks restrained the water flow as a strainer and improved the main channel stability. It is suggested to draw water at mean rate of 150 m3/s from the Huanghe River during flood periods, because at the rate the water in the wetland would be stored and replenished in balance. Moreover, we believe that cropland on the river shoal of the lower Huanghe River should be replaced by wetland. These activities should achieve the Huanghe River management strategy of "To concentrate flow to scour sediment, stabilize the main channel, and regulate water and sediment". 展开更多
关键词 Huanghe (Yellow) River estuary water and sediment regulation river channel adjustment wetland.
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Comparison of River Terraces in the Middle Reach Valleys of the Yellow River and Analysis on the Multi-Gradational Features of Tectonism in the Formation of Terrace Series
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作者 XingChengqi DingGuoyu +5 位作者 LuYanchou ShenXuhui TianQinjian YinGongming ChaiZhizhang WeiKaibo 《Earthquake Research in China》 2003年第2期183-198,共16页
Where the Yellow River flows through the Haiyuan-Tongxin arc-form tectonic region on the northeastern side of the Qinghai-Xizang (Tibet) Plateau, as many as 10~21 basis and erosion terraces have been produced, among ... Where the Yellow River flows through the Haiyuan-Tongxin arc-form tectonic region on the northeastern side of the Qinghai-Xizang (Tibet) Plateau, as many as 10~21 basis and erosion terraces have been produced, among which the biggest altitude above river level is 401m and the formation age of the highest terrace is 1.57 Ma B.P. Based on comparative analysis of the Yellow River terraces located separately in the Mijiashan mountain, the Chemuxia gorge, the Heishanxia gorge and the other river terraces in the vast extent of the northern part of China, it has been found that the tectonic processes resulting in the formation of the terrace series is one of multi-gradational features, i.e., a terrace series can include the various terraces produced by tectonic uplifts of different scopes or scales and different ranks. The Yellow River terrace series in the study region can be divided into three grades. Among them, in the first grade there are 6 terraces which were formed separately at the same time in the vast extent of the northern part of China and represent the number and magnitude of uplift of the Qinghai-Xizang Plateau since 1.6 Ma B. P.; in the second grade there are 5 terraces which were separately and simultaneously developed within the Haiyuan-Tianjingshan tectonic region and represent the number and magnitude of uplift of this tectonic region itself since 1.6Ma B.P.; in the third grade there are 10 terraces which developed on the eastern slope of the Mijiashan mountain and represent the number and amplitude of uplift of the Haiyuan tectonic belt itself since 1.6Ma B.P. Comparison of the terrace ages with loess-paleosoil sequence has also showed that the first grade terraces reflecting the vast scope uplifts of the Qinghai-Xizang Plateau are very comparable with climatic changes and their formation ages all correspond to the interglacial epochs during which paleosoils were formed. This implies that the vast extent tectonic uplifts resulting in river down-cutting are closely related to the warm-humid climatic periods which can also result in river downward erosion after strong dry and cold climatic periods, and they have jointly formed the tectonic-climatic cycles. There exists no unanimous and specific relationship between the formation ages of the second and third grade terraces and climatic changes and it is shown that the formation of those terraces was most mainly controlled by tectonic uplifts of the Tianjingshan block and the Haiyuan belt. The river terraces in the study region, therefore, may belong to 2 kinds of formation cause. One is a tectonic-climatic cyclical terrace produced jointly by vast extent tectonic uplifts and climatic changes, and the terraces of this kind are extensively distributed and can be well compared with each other among regions. Another is a pulse-tectonic cyclical terrace produced by local tectonic uplifts as dominant elements, and their distribution is restricted within an active belt and can not be compared with among regions. 展开更多
关键词 Comparison of river terraces Terrace series Multi-gradational features of tectonic process Origin of terraces Climatic changes The middle reaches of the Yellow River
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Lipids and fatty acids in Calanus sinicus during over-summering in the southern Yellow Sea 被引量:2
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作者 王延清 李超伦 +1 位作者 刘梦坛 金鑫 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2017年第4期874-882,共9页
Over-summering is a crucial period for Calanus sinicus in the southern Yellow Sea,where it is a key member of the zooplankton community.Lipids play an important role in copepod diapause,which is part of their over-sum... Over-summering is a crucial period for Calanus sinicus in the southern Yellow Sea,where it is a key member of the zooplankton community.Lipids play an important role in copepod diapause,which is part of their over-summering strategy.We investigated how different fatty acids and lipid classes,including wax esters,changed during over-summering of C.sinicus during three cruises in June and August 2011 and November 2010,corresponding to the pre-,during and post-diapause periods,respectively.Large amounts of lipids were accumulated,mainly wax esters as previously found in C.finmarchicus during its diapause,and most of the storage lipids were used during over-summering.Wax ester polyunsaturated fatty acids(PUFAs) showed the most variation of the fatty acids(FAs),while the percentage composition of FAs in polar lipids was relatively stable.Selective use of wax ester PUFAs has already been shown to play important roles in the winter diapause of Calanus species in other regions,and our FA results show that this is the case for the Yellow Sea Cold Bottom Water(YSCBW) population that diapauses in summer. 展开更多
关键词 Calanus sinicus LIPID wax ester polar lipid polyunsaturated fatty acids (PUFAs)
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