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A phylogenetic approach identifies patterns of beta diversity and floristic subregions of the Qinghai-Tibet Plateau
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作者 Haibin Yu Man Yang +7 位作者 Zixin Lu Weitao Wang Fangyuan Yu Yonghua Zhang Xue Yin Hongjun Yu Junjie Hu David C.Deane 《Plant Diversity》 SCIE CAS CSCD 2024年第1期59-69,共11页
Patterns of taxonomic and phylogenetic beta diversity and their relationships with environmental correlates can help reveal the origin and evolutionary history of regional biota.The Qinghai-Tibet Plateau(QTP)harbors a... Patterns of taxonomic and phylogenetic beta diversity and their relationships with environmental correlates can help reveal the origin and evolutionary history of regional biota.The Qinghai-Tibet Plateau(QTP)harbors an exceptionally diverse flora,however,a phylogenetic perspective has rarely been used to investigate its beta diversity and floristic regions.In this study,we used a phylogenetic approach to identify patterns of beta diversity and quantitatively delimit floristic regions on the Qinghai-Tibet Plateau.We also examined the relationships between multifaceted beta diversity,geographical distance,and climatic difference,and evaluated the relative importance of various factors(i.e.,climate,topography and history)in shaping patterns of beta diversity.Sørensen dissimilarity indices indicated that patterns of species turnover among sites dominated the QTP.We also found that patterns of both taxonomic and phylogenetic beta diversity were significantly related to geographical distance and climatic difference.The environmental factors that contributed most to these patterns of beta diversity include annual precipitation,mean annual temperature,climatic gradients and climatic instability.Hierarchical dendrograms of dissimilarity and non-metric multidimensional scaling ordination based on phylogenetic beta diversity data identified ten floristic subregions in the QTP.Our results suggest that the contemporary environment and historical climate changes have filtered species composition among sites and eventually determined beta diversity patterns of plants in the QTP. 展开更多
关键词 Biogeographical regionalization Phylogenetic beta diversity seed plants sørensen dissimilarity Qinghai-Tibet Plateau
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HBsAg和HBsAb共存的慢性乙肝患者的血清学特征和S区突变位点
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作者 刘辉 郄恒宇 +1 位作者 刘新 娄金丽 《标记免疫分析与临床》 CAS 2024年第3期393-398,共6页
目的探讨HBsAg/HBsAb双阳患者和HBsAg单阳性患者的血清学差异,并对两组患者的HBV S区突变位点进行比较分析,探寻HBsAg/HBsAb共阳性患者可能的分子机制。方法选取首都医科大学附属北京佑安医院2022年6月至2023年3月的284例HBsAg/HBsAb双... 目的探讨HBsAg/HBsAb双阳患者和HBsAg单阳性患者的血清学差异,并对两组患者的HBV S区突变位点进行比较分析,探寻HBsAg/HBsAb共阳性患者可能的分子机制。方法选取首都医科大学附属北京佑安医院2022年6月至2023年3月的284例HBsAg/HBsAb双阳患者和519例HBsAg单阳患者,统计Age、ALT、AST、AST/ALT、TBiL、ALb、r-GT、HBsAg和HBsAg滴度、HBsAb、HBeAg、HBeAb、HBcAb、WBC,对两组患者的血清学指标进行比较分析。对HBV S区扩增成功的19例HBsAg/HBsAb双阳患者和19例HBsAg单阳患者进行测序分析,统计高频突变位点,分析HBV S区突变特征,探寻HBsAg/HBsAb双阳患者可能发生的分子机制。结果HBsAg/HBsAb双阳患者和HBsAg单阳患者在性别、HBeAg、ALT、AST、TBiL、r-GT差异有统计学意义(P<0.05)。两组患者在Age、HBeAb、HBcAb、AST/ALT、Alb、WBC差异无统计学意义(P>0.05)。HBsAg/HBsAb双阳组患者C基因型占78.95%(15/19),其中A113D/T、A317C/S、A45T、A86G、A87T、A96V、A97P等突变频率较高,HBsAg单阳组C基因型占84.21%(16/19),V159A、M47T、I213L、A317S、E44G、Q267L突变频率较高,两组患者的高频突变位点明显不同。结论双阳和单阳CHB患者血清学和基因突变位点存在显著差异。建议针对HBV S区不同的突变位点进一步研究HBsAg和HBsAb共存的机制。 展开更多
关键词 HBsAG 跨膜结构域 主要亲水区 s
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Neural stem cell-derived exosomes promote mitochondrial biogenesis and restore abnormal protein distribution in a mouse model of Alzheimer's disease 被引量:1
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作者 Bo Li Yujie Chen +10 位作者 Yan Zhou Xuanran Feng Guojun Gu Shuang Han Nianhao Cheng Yawen Sun Yiming Zhang Jiahui Cheng Qi Zhang Wei Zhang Jianhui Liu 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第7期1593-1601,共9页
Mitochondrial dysfunction is a hallmark of Alzheimer’s disease.We previously showed that neural stem cell-derived extracellular vesicles improved mitochondrial function in the cortex of AP P/PS1 mice.Because Alzheime... Mitochondrial dysfunction is a hallmark of Alzheimer’s disease.We previously showed that neural stem cell-derived extracellular vesicles improved mitochondrial function in the cortex of AP P/PS1 mice.Because Alzheimer’s disease affects the entire brain,further research is needed to elucidate alterations in mitochondrial metabolism in the brain as a whole.Here,we investigated the expression of several important mitochondrial biogenesis-related cytokines in multiple brain regions after treatment with neural stem cell-derived exosomes and used a combination of whole brain clearing,immunostaining,and lightsheet imaging to clarify their spatial distribution.Additionally,to clarify whether the sirtuin 1(SIRT1)-related pathway plays a regulatory role in neural stem cell-de rived exosomes interfering with mitochondrial functional changes,we generated a novel nervous system-SIRT1 conditional knoc kout AP P/PS1mouse model.Our findings demonstrate that neural stem cell-de rived exosomes significantly increase SIRT1 levels,enhance the production of mitochondrial biogenesis-related fa ctors,and inhibit astrocyte activation,but do not suppress amyloid-βproduction.Thus,neural stem cell-derived exosomes may be a useful therapeutic strategy for Alzheimer’s disease that activates the SIRT1-PGC1αsignaling pathway and increases NRF1 and COXIV synthesis to improve mitochondrial biogenesis.In addition,we showed that the spatial distribution of mitochondrial biogenesis-related factors is disrupted in Alzheimer’s disease,and that neural stem cell-derived exosome treatment can reverse this effect,indicating that neural stem cell-derived exosomes promote mitochondrial biogenesis. 展开更多
关键词 Alzheimer’s disease mitochondrial biogenesis neural stem cell-derived exosome sIRT1-PGC1α regional brain distribution whole brain clearing and imaging
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基于CSLE的泛第三极地区土壤侵蚀强度空间分布特征
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作者 刘子玥 章文波 +4 位作者 殷兵 杨勤科 魏欣 刘宝元 殷水清 《水土保持研究》 CSCD 北大核心 2024年第3期1-9,共9页
[目的]定量评估泛第三极地区的土壤侵蚀状况,明确土壤侵蚀的分布特征,以期为土壤侵蚀的科学防治提供依据。[方法]基于分层不等概系统抽样方法,共布设31 406个调查单元。利用中国土壤流失方程CSLE计算泛第三极地区土壤侵蚀速率,并利用莫... [目的]定量评估泛第三极地区的土壤侵蚀状况,明确土壤侵蚀的分布特征,以期为土壤侵蚀的科学防治提供依据。[方法]基于分层不等概系统抽样方法,共布设31 406个调查单元。利用中国土壤流失方程CSLE计算泛第三极地区土壤侵蚀速率,并利用莫兰指数(I)探讨其分布特征。[结果](1)泛第三极地区平均土壤侵蚀速率为162.73 t/(km^(2)·a),水土流失面积比例为7.75%,土壤侵蚀速率超过500 t/(km^(2)·a)的地区主要位于西亚、东亚和南亚;(2)土壤侵蚀存在明显的空间聚集性(I=0.920 9),以高高型和低低型聚集为主,高高型聚集主要分布在西亚北部、南亚北部和西南部以及中国的东北、黄土高原和西藏南部;(3)草地、灌丛和耕地是土壤侵蚀较严重的土地利用类型,其中>1 000 m的草地、>500 m的灌丛和耕地的土壤侵蚀更严重,超过25%的土地都发生了水土流失,平均土壤侵蚀速率变化于426.85~683.72 t/(km^(2)·a)。[结论]海拔介于1 000~6 000 m的草地、500~4 000 m的灌丛以及1 000~4 000 m的耕地是泛第三极地区土壤侵蚀发生的重点区域,需特别关注。 展开更多
关键词 土壤侵蚀 泛第三极 空间分布 莫兰指数
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Impact of Different Rates of Nitrogen Supplementation on Soil PhysicochemicalProperties and Microbial Diversity in Goji Berry
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作者 Xiaojie Liang Wei An +4 位作者 Yuekun Li Yajun Wang Xiaoya Qin Yanhong Cui Shuchai Su 《Phyton-International Journal of Experimental Botany》 SCIE 2024年第3期467-486,共20页
Goji berry(Lycium barbarum L.)is substantially dependent on nitrogen fertilizer application,which can signifi-cantly enhance fruit yield and Goji berry industrial development in Ningxia,China.This study aimed to analyz... Goji berry(Lycium barbarum L.)is substantially dependent on nitrogen fertilizer application,which can signifi-cantly enhance fruit yield and Goji berry industrial development in Ningxia,China.This study aimed to analyze the functions of differential nitrogen application rates including low(N1),medium(N2),and high(N3)levels in soil microbial community structure(bacterial and fungal)at 2 diverse soil depths(0-20,20-40 cm)through high-throughput sequencing technology by targeting 16S RNA gene and ITS1&ITS2 regions.All the observed physicochemical parameters exhibited significant improvement(p<0.05)with increased levels of nitrogen and the highest values for most parameters were observed at N2.However,pH decreased(p<0.05)gradually.The alpha and beta diversity analyses for bacterial and fungal communities’metagenome displayed more similarities than differences among all groups.The top bacterial and fungal phyla and genera suggested no obvious(p>0.05)differences among three group treatments(N1,N2,and N3).Furthermore,the functional enrichment analysis demonstrated significant(p<0.05)enrichment of quorum sensing,cysteine and methionine metabolism,and transcriptional machinery for bacterial communities,while various saprotrophic functional roles for fungal communities.Conclusively,moderately reducing the use of N-supplemented fertilizers is conducive to increasing soil nitrogen utilization rate,which can contribute to sustainable agriculture practices through improved soil quality,and microbial community structure and functions. 展开更多
关键词 Goji berry production Ningxia China differential nitrogen supplementation rates 16s RNA gene and IT1&IT2 region sequencing soil physicochemical properties
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人民币对三种货币汇率波动特征与区域影响分析——基于MSAR模型及Bai-Perron检验
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作者 朱迪飞 《中国商论》 2024年第15期31-36,共6页
由于汇率时间序列经常呈现出波动的频繁性、非线性与易受国内外因素影响的特点,因此本文利用MSAR模型及Bai-Perron检验分析了人民币对美元、欧元、卢布的汇率波动所处的不同状态及结构性断点来捕捉汇率波动的结构性显著变化。党的二十... 由于汇率时间序列经常呈现出波动的频繁性、非线性与易受国内外因素影响的特点,因此本文利用MSAR模型及Bai-Perron检验分析了人民币对美元、欧元、卢布的汇率波动所处的不同状态及结构性断点来捕捉汇率波动的结构性显著变化。党的二十大报告指出有序推进人民币国际化,人民币国际化先从区域化开始,人民币影响力的体现是人民币汇率波动对其他国家汇率波动有显著的作用,这种作用相对主要国际货币如美元、日元、欧元、英镑等相当或影响更大,因此选取与我国贸易往来密切的周边东南亚及亚太等八个国家的货币汇率波动作为分析对象,同样运用MSAR模型进行实证检验。结果表明,人民币汇率对以上选取货币汇率具有两种状态的明显转换特点,且人民币汇率波动在升值和贬值两种状态下对其他货币的升值和贬值起到一定的作用,这种作用与国际货币相当,人民币在周边区域表现出一定的影响力。 展开更多
关键词 汇率波动 结构突变点 平滑概率 MsAR模型 人民币区域化
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2015年12月7日塔吉克斯坦M_(S)7.4地震对远场小震活动的动态应力触发 被引量:2
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作者 魏芸芸 王琼 +3 位作者 陈昊 钱才 向元 张琳琳 《内陆地震》 2023年第1期1-11,共11页
采用离散波数法计算2015年12月7日塔吉克斯坦M_(S)7.4地震远场产生的库仑破裂应力变化,并结合β统计值检验方法,分析该地震对远场区域地震活动的应力触发作用。结果表明,①塔吉克斯坦M_(S)7.4地震在新疆库车、巴楚和喀什-乌恰地区的远... 采用离散波数法计算2015年12月7日塔吉克斯坦M_(S)7.4地震远场产生的库仑破裂应力变化,并结合β统计值检验方法,分析该地震对远场区域地震活动的应力触发作用。结果表明,①塔吉克斯坦M_(S)7.4地震在新疆库车、巴楚和喀什-乌恰地区的远场接收点产生动态应力变化为正,变化峰值分别为1.31 MPa、0.14 MPa和0.5 MPa,对库车和喀什-乌恰地区小震活动具有动态触发作用,与此相关,β统计值结果显示,塔吉克斯坦M_(S)7.4地震后库车地区地震活动性发生了较明显的改变,这与库车地区接收点库仑应力变化大小一致。②塔吉克斯坦M_(S)7.4地震在2016年11月25日阿克陶M_(S)6.7地震震中位置造成的最大动态库仑应力变化为1.0 MPa,表明阿克陶M_(S)6.7地震可能受到了塔吉克斯坦M_(S)7.4地震的应力触发作用,动态触发作用更为明显。 展开更多
关键词 塔吉克斯坦M_(s)7.4地震 动态应力触发 β统计值 区域地震活动
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基于Faster R-CNN的密集人群检测算法 被引量:4
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作者 邹斌 张聪 《计算机应用》 CSCD 北大核心 2023年第1期61-66,共6页
为提高拥挤场景下的人群检测准确率,提出一种基于改进Faster R-CNN的密集人群检测算法。首先,在特征提取阶段添加空间与通道注意力机制,使用加强的双向特征金字塔网络(S-BiFPN)替代原网络中的多尺度特征金字塔(FPN),使网络对重要特征进... 为提高拥挤场景下的人群检测准确率,提出一种基于改进Faster R-CNN的密集人群检测算法。首先,在特征提取阶段添加空间与通道注意力机制,使用加强的双向特征金字塔网络(S-BiFPN)替代原网络中的多尺度特征金字塔(FPN),使网络对重要特征进行自主学习并加强对图像深层特征的提取;其次,引入多实例预测(MIP)算法对实例进行预测,以避免模型对拥挤场景下的目标造成漏检;最后,对模型中的非极大值抑制(NMS)进行优化,并额外增设一个交并比(IoU)阈值,以对检测结果的干扰项进行精确抑制。在开源的密集人群检测数据集上进行测试的结果显示,相较于原Faster R-CNN算法,所提算法的平均精度(AP)提升5.6%,Jaccard指数值提升3.2%。所提算法具有较高检测精度和稳定性,可以满足密集场景人群检测的需求。 展开更多
关键词 密集人群检测 Faster R-CNN 注意力机制 多实例预测 加强的双向特征金字塔网络
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Discovering Crustal Deformation Bands by Processing Regional Gravity Field 被引量:11
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作者 YANG Wencai SUN Yanyun 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2016年第1期66-74,共9页
Objectives: This article presents a new computational procedure to discover scratches buried in the earth's crust. We also validate this new interdisciplinary analysis method with regional gravity data located in a ... Objectives: This article presents a new computational procedure to discover scratches buried in the earth's crust. We also validate this new interdisciplinary analysis method with regional gravity data located in a well-known Dabie orogenic zone for test. Methods: Based on the scratch analysis method evolved with mathematical morphology of surfaces, we present a procedure that extracts information of the crustal scratches from regional gravity data. Because the crustal scratches are positively and highly correlated to crustal deformation bands, it can be used for delineation of the crustal deformation belts. The scratches can be quantitatively characterized by calculation of the ridge coefficient function, whose high value traces delineate the deformation bands hidden in the regional gravity field. In addition, because the degree of crustal deformation is an important indicator of tectonic unit divisions, so the crust can be further divided according to the degree of crustal deformation into some tectonic units by using the ridge coefficient data, providing an objective base map for earth scientists to build tectonic models with quantitative evidence. Results: After the ridge coefficients are calculated, we can further enhance the boundary of high ridge-coefficient blocks, resulting in the so-called ridge-edge coefficient function. The high-value ridge-edge coefficients are well correlated with the edge faults of tectonic units underlay, providing accurate positioning of the base map for compilation of regional tectonic maps. In order to validate this new interdisciplinary analysis method, we select the Dabie orogenic zone as a pilot area for test, where rock outcrops are well exposed on the surface and detailed geological and geophysical surveys have been carried out. Tests show that the deformation bands and the tectonic units, which are conformed by tectonic scientists based on surface observations, are clearly displayed on the ridge and ridge-edge coefficient images obtained in this article. Moreover, these computer-generated images provide more accurate locations and geometric details. Conclusions: This work demonstrates that application of modern mathematical tools can promote the quantitative degree in research of modern geosciences, helping to open a door to develop a new branch of mathematical tectonics. 展开更多
关键词 TECTONICs earth's crust deformation band regional gravity field information extraction scratch analysis computer-generated image
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Q value of anelastic S-wave attenuation in Yunnan region 被引量:1
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作者 苏有锦 刘杰 +3 位作者 郑斯华 刘丽芳 付虹 徐彦 《Acta Seismologica Sinica(English Edition)》 CSCD 2006年第2期217-224,共8页
The study of seismic attenuation property is a major subject in seismology. Seismic waves recorded by seismic stations (seismographs) contain source effect, seismic wave propagation effect, site response of seismic ... The study of seismic attenuation property is a major subject in seismology. Seismic waves recorded by seismic stations (seismographs) contain source effect, seismic wave propagation effect, site response of seismic stations and instrumental response. The path effect of seismic wave propagation, site response of seismic stations and instrumental response must be taken out in the study of source property with seismic data. The path effect of seismic wave propagation (seismic attenuation) involves an important influential factor, the anelastic attenuation of medium, which is measured with quality factor Q, apart from geometric attenuation with the distance. As a basic physical parameter of the Earth medium, Q value is essential for quantitative study of earthquakes and source property (e.g. determination of source parameters), which is widely used in earthquake source physics and engineering seismology. 展开更多
关键词 s wave anelastic attenuation Q value Yunnan region
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Liver Transplantation (in Chinese), revised edition, Edited by Shu-Sen Zheng. Pp843. Beijing: People's Medical Publishing House, 2012. ISBN: 978-7-117-15494-9/R.15495. ¥RMB 158 被引量:3
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《Hepatobiliary & Pancreatic Diseases International》 SCIE CAS 2012年第6期649-649,共1页
Liver Transplantation (in Chinese), revised edition, edited by Professor Shu-Sen Zheng and prefaced by Professor Guo-Wei Sang, has just been published. The revised edition is mainly based on the clinical practice of t... Liver Transplantation (in Chinese), revised edition, edited by Professor Shu-Sen Zheng and prefaced by Professor Guo-Wei Sang, has just been published. The revised edition is mainly based on the clinical practice of the Liver Transplant Center, the First Affiliated Hospital, Zhejiang University and the experience 展开更多
关键词 in Chinese BEIJING Edited by shu-sen Zheng People’s Medical Publishing House Pp843 R.15495 rmb 158
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Seismicity,structure and tectonics in the Arctic region 被引量:2
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作者 Masaki Kanao Vladimir D.Suvorov +1 位作者 Shigeru Toda Seiji Tsuboi 《Geoscience Frontiers》 SCIE CAS CSCD 2015年第5期665-677,共13页
The "Arctic" region,where the North Pole occupies the center of the Arctic Ocean,has been affecting the environmental variation of the Earth from geological time to the present.However,the seismic activities... The "Arctic" region,where the North Pole occupies the center of the Arctic Ocean,has been affecting the environmental variation of the Earth from geological time to the present.However,the seismic activities in the area are not adequately monitored.Therefore,by conducting long term monitoring of seismic phenomenon as sustainable parameters,our understanding of both the tectonic evolution of the Earth and the dynamic interaction between the cryosphere and geosphere in surface layers of the Earth will increase.In this paper,the association of the seismicity and structure of the Arctic region,particularly focused on Eurasian continent and surrounding oceans,and its relationship with regional evolution during the Earth’s history is studied.The target areas cover representative tectonic provinces in the Eurasian Arctic,such as the wide area of Siberia,Baikal Rift Zone.Far East Russia,Arctic Ocean together with Greenland and Northern Canada.Based on discussion including characteristics of seismicity,heterogeneous structure of the crust and upper mantle,tectonic history and recent dynamic features of the Earth’s surface in the Arctic are summarized. 展开更多
关键词 Arctic region sEIsMICITY TECTONICs Earth’s structu
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基于熵产理论的水泵水轮机反S区水力损失机理分析 被引量:5
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作者 阚阚 杨皓程 +2 位作者 郑源 段慧玲 陈会向 《水利学报》 EI CSCD 北大核心 2023年第3期323-332,共10页
水泵水轮机在水轮机工况运行时易进入反S不稳定区,影响机组的安全稳定运行。传统压差法在计算水力损失时不能获得损失的具体分布和详细来源,因此水泵水轮机在反S区水力损失机理仍有待深入研究。本文采用雷诺时均方法对某原型抽蓄电站水... 水泵水轮机在水轮机工况运行时易进入反S不稳定区,影响机组的安全稳定运行。传统压差法在计算水力损失时不能获得损失的具体分布和详细来源,因此水泵水轮机在反S区水力损失机理仍有待深入研究。本文采用雷诺时均方法对某原型抽蓄电站水泵水轮机在活动导叶开度分别为12°和35°下的反S区运行工况进行了数值模拟,基于熵产理论对各个过流部件和不同类型的水力损失进行了定量分析,并结合流场分布情况进一步明确了水力损失的分布特点和产生原因。结果表明,水泵水轮机进入反S区会引起导叶段水力损失占总水力损失的比例逐渐增大,而转轮段水力损失逐渐减小。在不同类型的能量损失中,湍流熵产占据主导,壁面熵产次之,直接熵产最小。随着水泵水轮机进入深度反S区,转轮区湍流熵产损失较大区域从转轮进口的叶片压力面转移到转轮出口叶片吸力面。水泵水轮机位于反S区时,转轮对水流做功输入能量,使无叶区总压大幅上升,活动导叶开度增大会显著增大无叶区水流能量幅值。 展开更多
关键词 水泵水轮机 数值模拟 熵产理论 s 水力损失
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Regional variation of pediatric inflammatory bowel disease in Saudi Arabia: Results from a multicenter study 被引量:1
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作者 Mohammad I El Mouzan Mohammed H AlEdreesi +3 位作者 Mohammed Y Hasosah Abdulrahman A Al-Hussaini Ahmad A Al Sarkhy Asaad A Assiri 《World Journal of Gastroenterology》 SCIE CAS 2020年第4期416-423,共8页
BACKGROUND Incidence and severity variations of inflammatory bowel disease(IBD)have been reported from Western populations between continents and regions of the same countries.However,no data were available from other... BACKGROUND Incidence and severity variations of inflammatory bowel disease(IBD)have been reported from Western populations between continents and regions of the same countries.However,no data were available from other countries.AIM To investigate the regional differences in the IBD profiles of pediatric patients from the Kingdom of Saudi Arabia.METHODS Data from a national multicenter IBD study were used.The incidence,time trend,and clinical presentation of Crohn’s disease(CD)and ulcerative colitis(UC)in the Central region(CR),Western region(WR),and Eastern region(ER)were analyzed and compared.Statistical analysis included Poisson regression analysis for incidence variation and Chi-square test for demographic and clinical parameters.A P<0.05 was considered significant.RESULTS The prevalence of positive family history was lower in children with CD from the ER than the CR or the WR.Consanguinity rate was higher in children with CD and UC from the CR and the ER,respectively.The incidences and time trends of CD and UC were not significantly different between regions.In the ER,a significantly higher percentage of children with CD presented with abdominal pain(P<0.001),blood in stools(P=0.048),stricturing or penetrating disease(P=0.029),higher erythrocyte sedimentation rate(P<0.001),higher C-reactive protein(P<0.001),higher anemia(P=0.017),and lower albumin level(P=0.014).For children with UC from the ER,a significantly higher percentage presented with anemia(P=0.006)and a lower percentage with pancolitis(P<0.001).CONCLUSION The most important finding is the identification of significantly more severe presentation of CD in the ER of the Kingdom of Saudi Arabia.Prospective studies are needed to explain such variations. 展开更多
关键词 Crohn’s disease Ulcerative colitis EPIDEMIOLOGY CHILDREN regional variation
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Comparative analysis on microbial community associated with different gastrointestinal regions of wild northern snakehead Channa argus Cantor, 1842 被引量:1
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作者 苗淑彦 赵臣泽 +1 位作者 朱锦裕 潘明珠 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2018年第2期450-456,共7页
Microbial communities in different gastrointestinal regions(stomach, foregut, midgut, and hindgut) of the northern snakehead C hanna argus(Cantor, 1842) were compared by polymerase chain reaction and partial 16 S r DN... Microbial communities in different gastrointestinal regions(stomach, foregut, midgut, and hindgut) of the northern snakehead C hanna argus(Cantor, 1842) were compared by polymerase chain reaction and partial 16 S r DNA sequencing. A total of 194, 140, 212, and 122 OTUs were detected in the stomach, foregut, midgut, and hindgut, respectively. Significant dif ferences were found in the Sobs, ACE, Shannon, and Simpson indices among samples(P <0.05). The gastrointestinal microbial community of C. argus consisted predominantly of Proteobacteria with either H alomonas, Shewanella, Plesiomonas, or Sphingomonas. Fusobacteria, Firmicutes, and Bacteroidetes also existed in the gastrointestinal tracts. However, significant diff erences were found in the compositions of microbial community among the four regions( P <0.05). Cyanobacteria and Spirochetes were significantly higher in the midgut and hindgut( P <0.05). Fusobacteria and Firmicutes were dominant in the hindgut and foregut, respectively(P <0.05). Proteobacteria was the lowest in the hindgut( P <0.05). At genus level, C etobacterium and Plesiomonas were significantly higher in the hindgut than in the other three samples( P <0.05). Clostridium and Prevotella were the highest in the midgut(P <0.05). Halomonas, Shewanella, and S phingomonas were the highest in the foregut( P <0.05). Paracoccus and Vibrio were the highest in the stomach. Several genera were only detected in certain regions, as follows: stomach, P aracoccus and Vibrio; foregut, Halomonas, Shewanella, and Sphingomonas; midgut, Clostridium and Prevotella; and hindgut, C etobacterium and Plesiomonas( P <0.05). At the species level, A cinetobacter rhizosphaerae was only detected in the stomach. P revotella copri and Clostridium perfring were not detected in the foregut and midgut, respectively, whereas Prevotella copri and Faecalibacterium pra were not detected in the hindgut. These findings provide valuable information on the microbial community in each gastrointestinal region of C. argus. Moreover, this study indicated that microbial community was not only related to rearing environment but also to the physico-chemical characteristics of each gastrointestinal region. 展开更多
关键词 northern snakehead (Channa argus Cantor 1842) 16s rDNA microbial community gastrointestinal region physico-chemical characteristic
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Application of Land-use Change Model in Guiding Regional Planning:A Case Study in Hun-Taizi River Watershed,Northeast China 被引量:11
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作者 LIU Miao HU Yuanman +3 位作者 ZHANG Wei ZHU Junjun CHEN Hongwei XI Fengming 《Chinese Geographical Science》 SCIE CSCD 2011年第5期609-618,共10页
This paper firstly investigated the land-use and land-cover change (LUCC) in the Hun-Taizi River watershed, Northeast China from 1988 to 2004 based on remotely sensed images and geographic information systems (GIS) te... This paper firstly investigated the land-use and land-cover change (LUCC) in the Hun-Taizi River watershed, Northeast China from 1988 to 2004 based on remotely sensed images and geographic information systems (GIS) technology. Then, using the famous land-use change model of Conversion of Land Use and its Effects at Small regional extent (CLUE-S), this paper simulated the land use changes under historical trend (HT), urban planning (UP) and ecological protection (EP) scenarios considering urban planning and ecological protection over the next 20 years. The simulated results under UP scenario in 2020 were compared with the planning map to assess the feasibility of using land-use change model to guide regional planning. Results show that forest land, dry farmland, paddy, and shrub land were the main land-use categories. Paddy and dry farmland being converted to urban area and rural settlement characterized the land-use change from 1988 to 2004. The main land-use categories changed over time. Landscape-pattern fragmentation will be worse under HT and UP scenarios, but better in EP scenario. The comparing results of simulated map with planning map in 2020 show that land-use change model is powerful tool to guide regional planning. Land-use scenarios can support regional planning and policy-making through analyzing future consequences scientifically. 展开更多
关键词 土地利用变化 中国东北地区 区域规划 太子河流域 变化模型 浑河 应用 案例
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泸定M_(S)6.8地震前后川滇强震活动幕式图像分析
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作者 朱航 《地震地磁观测与研究》 2023年第S01期255-257,共3页
1研究背景2022年9月5日四川泸定发生M_(S)6.8地震,该事件对于未来强震活动形势发展及主体活动区域转移有何意义,是目前关注的焦点。本文继承了黄圣睦(2000)的川滇地区幕式结构研究思路和判定依据,其主要内容为:川滇作为一个地震构造块体... 1研究背景2022年9月5日四川泸定发生M_(S)6.8地震,该事件对于未来强震活动形势发展及主体活动区域转移有何意义,是目前关注的焦点。本文继承了黄圣睦(2000)的川滇地区幕式结构研究思路和判定依据,其主要内容为:川滇作为一个地震构造块体,有着相同的新构造环境和地震活动紧密相连的充分依据。川滇之间没有像四川和甘肃或四川和青海之间存在的EW向秦岭构造带的横亘、阻截,将四川和云南作为整体研究,其幕式活动图像明显,可以比较容易把握强震活动规律。 展开更多
关键词 川滇地区 强震活动 活跃幕 泸定M_(s)6.8地震
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R/S AND WAVELET ANALYSIS ON EVOLUTIONARYPROCESS OF REGIONAL ECONOMIC DISPARITY IN CHINA DURING PAST 50 YEARS 被引量:9
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作者 XUJian-hua LUYan +1 位作者 SUFang-lin AINan-shan 《Chinese Geographical Science》 SCIE CSCD 2004年第3期193-201,共9页
This paper shows the dynamic process of regional disparity of economic development in China in the past 50 years from a new insight by using the rescaled range statistic (R/S) analysis and wavelet analysis of the Thei... This paper shows the dynamic process of regional disparity of economic development in China in the past 50 years from a new insight by using the rescaled range statistic (R/S) analysis and wavelet analysis of the Theil index sequence with different time scales. The main conclusions are: 1) The regional disparity of economic development in China, including the inter-provincial disparity, inter-regional disparity and intra-regional disparity, has existed for many years. Theil index by the comparative price has revealed the true trend for comparative disparity of regional economic development from 1952 to 2000. 2) Decomposition of Theil index indicates that the dynamic trend of comparative inter-provincial disparity in the coastal region is in line with dynamic trend of inter-provincial disparity in the whole China. 3) The R/S analysis results tell us that during 1966-1978, the Hurst exponent H=0.504≈0.5, which indicates that in that period the evolution of comparative inter-provincial disparity of economic development showed a random characteristic, and in the other periods, i.e. 1952-1965, 1979-1990 and 1991-2000, the Hurst exponent H>0.5, which indicates that in those periods the evolution of the comparative inter-provincial disparity of economic development in China had a long-enduring characteristic. 4) By using wavelet analysis at different time scale, we arrived at a conclusion that the evolutionary process of the disparity of economic development of China is not a simple inverted U shape but a compound of several U shapes. The result tells us that the evolutionary plot of inter-provincial disparity in China follows the inverted U on the whole at the higher scale, 24(16 years). That is to say, the disparity tends to rise in the first stage of economic development, and fall slowly over the peak in the second stage of economic development. However, if we shorten the time scale to 23 (8 years), then a link of several U shapes will appear. 展开更多
关键词 区域经济发展 经济差异 统计学 小波分析
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The World's Largest Soda-Niter Ore Intensive Region Found in the Turpan–Hami Basin 被引量:1
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作者 Hao Ziguo,Fei Hongcai, Liu Lian 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2012年第3期789-789,共1页
The Xinjiang Geology and Mineral Resources Exploration and Development Bureau have conducted a detailed investigation project of the Xigobi soda-niter deposit in Hami, Xinjiang Province, which was completed at the end... The Xinjiang Geology and Mineral Resources Exploration and Development Bureau have conducted a detailed investigation project of the Xigobi soda-niter deposit in Hami, Xinjiang Province, which was completed at the end of 2011. The project put much emphasis on research of soda-niter mineralization rules, stratum classification, ore-forming 展开更多
关键词 Hami Basin World The World’s Largest soda-Niter Ore Intensive region Found in the Turpan
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A GIS-based Modeling Approach for Fast Assessment of Soil Erosion by Water at Regional Scale, Loess Plateau of China 被引量:2
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作者 HU Llangjun YANG Haijun +1 位作者 YANG Qinke LI Rui 《Chinese Geographical Science》 SCIE CSCD 2010年第5期423-433,共11页
The objective of this study is to develop a unique modeling approach for fast assessment of massive soil erosion by water at a regional scale in the Loess Plateau, China. This approach relies on an understanding of bo... The objective of this study is to develop a unique modeling approach for fast assessment of massive soil erosion by water at a regional scale in the Loess Plateau, China. This approach relies on an understanding of both regional patterns of soil loss and its impact factors in the plateau area. Based on the regional characteristics of pre- cipitation, vegetation and land form, and with the use of Landsat TM and ground investigation data, the entire Loess Plateau was first divided into 3 380 Fundamental Assessment Units (FAUs) to adapt to this regional modeling and fast assessment. A set of easily available parameters reflecting relevant water erosion factors at a regional scale was then developed, in which dynamic and static factors were discriminated. ArcInfo GIS was used to integrate all es- sential data into a central database. A resulting mathematical model was established to link the sediment yields and the selected variables on the basis of FAUs through overlay in GIS and multiple regression analyses. The sensitivity analyses and validation results show that this approach works effectively in assessing large area soil erosion, and also helps to understand the regional associations of erosion and its impact factors, and thus might significantly contribute to planning and policymaking for a large area erosion control in the Loess Plateau. 展开更多
关键词 中国黄土高原 快速评估 土壤侵蚀 区域尺度 建模方法 降水 基础地理信息系统 GIs
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