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Tour Level Mode Choice Analysis of Madison Area in Wisconsin
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作者 Zhang Miao Cheng Yang 《Chinese Journal of Population,Resources and Environment》 北大核心 2008年第3期90-92,共3页
This study is to investigate what factors and how they affect tours (trip chains) behavior. The key issue is the understanding and definition of tour and tour level mode. Also, these definitions should fit for the dat... This study is to investigate what factors and how they affect tours (trip chains) behavior. The key issue is the understanding and definition of tour and tour level mode. Also, these definitions should fit for the data. A semi-home based tour definition is stated, and a competing mode based tour mode is defined. Based on the definition, this study used Madison Area Data from National Household Survey to estimate a MNL structured model. It is found that travel distance could be a positive factor for car mode. Meanwhile, the number of trips is also a positive factor for choosing car. 展开更多
关键词 trip chaining multi-nominal logit model mode choice travel behavior tour analysis
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The secondary injury cascade after spinal cord injury:an analysis of local cytokine/chemokine regulation 被引量:2
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作者 Daniel J.Hellenbrand Charles M.Quinn +8 位作者 Zachariah J.Piper Ryan T.Elder Raveena R.Mishra Taylor L.Marti Phoebe M.Omuro Rylie M.Roddick Jae Sung Lee William L.Murphy Amgad S.Hanna 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第6期1308-1317,共10页
After spinal cord injury,there is an extensive infiltration of immune cells,which exacerbates the injury and leads to further neural degeneration.Therefore,a major aim of current research involves targeting the immune... After spinal cord injury,there is an extensive infiltration of immune cells,which exacerbates the injury and leads to further neural degeneration.Therefore,a major aim of current research involves targeting the immune response as a treatment for spinal cord injury.Although much research has been performed analyzing the complex inflammatory process following spinal cord injury,there remain major discrepancies within previous literature regarding the timeline of local cytokine regulation.The objectives of this study were to establish an overview of the timeline of cytokine regulation for 2 weeks after spinal cord injury,identify sexual dimorphisms in terms of cytokine levels,and determine local cytokines that significantly change based on the severity of spinal cord injury.Rats were inflicted with either a mild contusion,moderate contusion,severe contusion,or complete transection,7 mm of spinal cord centered on the injury was harvested at varying times post-injury,and tissue homogenates were analyzed with a Cytokine/Chemokine 27-Plex assay.Results demonstrated pro-inflammatory cytokines including tumor necrosis factorα,interleukin-1β,and interleukin-6 were all upregulated after spinal cord injury,but returned to uninjured levels within approximately 24 hours post-injury,while chemokines including monocyte chemoattractant protein-1 remained upregulated for days post-injury.In contrast,several anti-inflammatory cytokines and growth factors including interleukin-10 and vascular endothelial growth factor were downregulated by 7 days post-injury.After spinal cord injury,tissue inhibitor of metalloproteinase-1,which specifically affects astrocytes involved in glial scar development,increased more than all other cytokines tested,reaching 26.9-fold higher than uninjured rats.After a mild injury,11 cytokines demonstrated sexual dimorphisms;however,after a severe contusion only leptin levels were different between female and male rats.In conclusion,pro-inflammatory cytokines initiate the inflammatory process and return to baseline within hours post-injury,chemokines continue to recruit immune cells for days post-injury,while anti-inflammatory cytokines are downregulated by a week post-injury,and sexual dimorphisms observed after mild injury subsided with more severe injuries.Results from this work define critical chemokines that influence immune cell infiltration and important cytokines involved in glial scar development after spinal cord injury,which are essential for researchers developing treatments targeting secondary damage after spinal cord injury. 展开更多
关键词 ASTROCYTES CHEMOKINES cytokines inflammation macrophages MICROGLIA secondary damage spinal cord injury
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Extreme Antarctic Cold of Late Winter 2023 被引量:1
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作者 Anastasia J.TOMANEK David E.MIKOLAJCZYK +7 位作者 Matthew A.LAZZARA Stefano DI BATTISTA Minghu DING Mariana FONTOLAN LITELL David H.BROMWICH Taylor P.NORTON Linda M.KELLER Lee J.WELHOUSE 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第10期1873-1880,共8页
Extreme cold temperatures were observed in July and August 2023,coinciding with the WINFLY(winter fly-in)period of mid to late August into September 2023,meaning aircraft operations into McMurdo Station and Phoenix Ai... Extreme cold temperatures were observed in July and August 2023,coinciding with the WINFLY(winter fly-in)period of mid to late August into September 2023,meaning aircraft operations into McMurdo Station and Phoenix Airfield were adversely impacted.Specifically,with temperatures below−50℃,safe flight operation was not possible because of the risk of failing hydraulics and fuel turning to gel onboard the aircraft.The cold temperatures were measured across a broad area of the Antarctic,from East Antarctica toward the Ross Ice Shelf,and stretching across West Antarctica to the Antarctic Peninsula.A review of automatic weather station measurements and staffed station observations revealed a series of sites recording new record low temperatures.Four separate cold phases were identified,each a few days in duration and occurring from mid-July to the end of August 2023.A brief analysis of 500-hPa geopotential height anomalies shows how the mid-tropospheric atmospheric environment evolves in relation to these extreme cold temperatures.The monthly 500-hPa geopotential height anomalies show strong negative anomalies in August.Examination of composite geopotential height anomalies during each of the four cold phases suggests various factors leading to cold temperatures,including both southerly off-content flow and calm atmospheric conditions.Understanding the atmospheric environment that leads to such extreme cold temperatures can improve prediction of such events and benefit Antarctic operations and the study of Antarctic meteorology and climatology. 展开更多
关键词 ANTARCTICA extreme cold temperature automatic weather station networks
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The 18th Workshop on Antarctic Meteorology and Climate
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作者 Anastasia J.TOMANEK Ethan J.KOUDELKA +4 位作者 Mariana F.LITELL Taylor P.NORTON Mckenzie J.DICE Isabella I.ONSI Matthew A.LAZZARA 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2024年第12期2495-2504,共10页
The 18th Workshop on Antarctic Meteorology and Climate was held on 31 May through 2 June 2023.The Antarctic Meteorological Research and Data Center hosted this hybrid workshop at the Pyle Center at the University of W... The 18th Workshop on Antarctic Meteorology and Climate was held on 31 May through 2 June 2023.The Antarctic Meteorological Research and Data Center hosted this hybrid workshop at the Pyle Center at the University of Wisconsin-Madison in Madison,WI,USA.Global members of the Antarctic meteorological community gathered to present and discuss topics from scientific research to operational support within Antarctic meteorology and climate.Students and early career professionals chaired various presentations and discussions while all attendees engaged to share results,build collaborative plans,and discuss further developments.The main workshop topics included updates on the current Automatic Weather Station(AWS)networks,challenges,and planning concerning Antarctic forecasting and operational services,Antarctic numerical modeling systems,observational applications and research,and Antarctic community and data sources.Across six sessions,over 25 different presenters elaborated on their work in areas such as field season updates,atmospheric rivers,remote sensing,the Antarctic Mesoscale Prediction System(AMPS),and forecasting challenges due to data scarcity.Workshop discussions resulted in several key outcomes and action items regarding fieldwork impacts,exploration of field techniques,observation coverage,and communication between operations and research scientists.Future workshops will provide opportunities for continued discussion on the evolution of the AWS network and operational needs while providing a venue to promote collaboration and cooperation for Antarctic meteorology and climate activities. 展开更多
关键词 ANTARCTICA polar meteorology automatic weather station polar modeling polar climatology
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Laboratory visualization of damage asymmetry formation of rock fracture via acoustic emission and digital imaging correlation
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作者 Qiquan Xiong Qing Lin +2 位作者 Yue Gao Yanhui Han Jesse C.Hampton 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第11期4480-4490,共11页
Rock fracture mechanics and accurate characterization of rock fracture are crucial for understanding a variety of phenomena interested in geological engineering and geoscience.These phenomena range from very large-sca... Rock fracture mechanics and accurate characterization of rock fracture are crucial for understanding a variety of phenomena interested in geological engineering and geoscience.These phenomena range from very large-scale asymmetrical fault structures to the scale of engineering projects and laboratory-scale rock fracture tests.Comprehensive study can involve mechanical modeling,site or post-mortem investigations,and inspection on the point cloud of the source locations in the form of earthquake,microseismicity,or acoustic emission.This study presents a comprehensive data analysis on characterizing the forming of the asymmetrical damage zone around a laboratory mixed-mode rock fracture.We substantiate the presence of asymmetrical damage through qualitative analysis and demonstrate that measurement uncertainties cannot solely explain the observed asymmetry.The implications of this demonstration can be manifold.On a larger scale,it solidifies a mechanical model used for explaining the contribution of aseismic mechanisms to asymmetrical fault structures.On a laboratory scale,it exemplifies an alternative approach to understanding the observational difference between the source location and the in situ or post-mortem inspection on the rock fracture path.The mechanical model and the data analysis can be informative to the interpretations of other engineering practices as well,but may face different types of challenges. 展开更多
关键词 Shear fracture Dynamics of fracture Acoustic emission Digital image correlation Uncertainty analysis Error ellipsoid
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Temporal trends and cohort variations of gender-specific major depressive disorders incidence in China:analysis based on the age-period-cohortinteraction model
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作者 Xiyuan Hu Chao Guo 《General Psychiatry》 CSCD 2024年第4期473-479,共7页
Background Major depressive disorders(MDDs)impose substantial burdens on individuals and society;however,further detailed analysis is still needed for its long-term trends.Aims This study aimed to analyse the gender-s... Background Major depressive disorders(MDDs)impose substantial burdens on individuals and society;however,further detailed analysis is still needed for its long-term trends.Aims This study aimed to analyse the gender-specific temporal trends and cohort variations of MDD incidence among Chinese residents over the past three decades.Methods Employing the age-period-cohort-interaction model and leveraging data from the Global Burden of Disease Study 2019,this research identified and analysed incidence trends of MDD among Chinese males and females aged 5-94 years from 1990 to 2019 across three dimensions,encompassing age,period and birth cohort.Results The analysis reveals age-related effects,indicating heightened MDD risk among adolescents and older adults.Specifically,individuals entering the older adulthood at the age of 65-69 significantly increased the risk of MDD by 64.9%.People aged 90-94 years witnesseda 105.4%increase in MDD risk for the overall population,with females and males in this age group experiencing a 75.1%and 103.4%increase,respectively.In terms of period effects,the risk of MDD displayed a decline from 1990 to 1994,followed by a rebound in 2008.Cohort effects demonstrated diverse generational patterns,with generationⅠand generationⅢmanifesting opposing‘age-as-level'trends.GenerationⅡand generationⅣexhibited'cumulative disadvantage'and'cumulative advantage'patterns,respectively.Age effects indicated an overall higher risk of MDD incidence in females,while cohort effects showed greater variations of MDD incidence among females.Conclusions The study underscores the substantial effects of age,period and cohort on MDD across genders in China.Priority interventions targeting vulnerable populations,including children,adolescents,older adults,females and the post-millennium birth cohort,are crucial to mitigate the impact of MDD. 展开更多
关键词 INTERACTION ANALYSIS INCIDENCE
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Bacteria colonization and gene expression related to immune function in colon mucosa is associated with growth in neonatal calves regardless of live yeast supplementation
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作者 Koki Nishihara Clothilde Villot +2 位作者 Lautaro Cangiano Le Luo Guan Michael Steele 《Journal of Animal Science and Biotechnology》 SCIE CAS CSCD 2024年第5期1980-1995,共16页
Background As Holstein calves are susceptible to gastrointestinal disorders during the first week of life,understanding how intestinal immune function develops in neonatal calves is important to promote better intesti... Background As Holstein calves are susceptible to gastrointestinal disorders during the first week of life,understanding how intestinal immune function develops in neonatal calves is important to promote better intestinal health.Feeding probiotics in early life may contribute to host intestinal health by facilitating beneficial bacteria colonization and developing intestinal immune function.The objective of this study was to characterize the impact of early life yeast supplementation and growth on colon mucosa-attached bacteria and host immune function.Results Twenty Holstein bull calves received no supplementation(CON)or Saccharomyces cerevisiae boulardii(SCB)from birth to 5 d of life.Colon tissue biopsies were taken within 2 h of life(D0)before the first colostrum feeding and 3 h after the morning feeding at d 5 of age(D5)to analyze mucosa-attached bacteria and colon transcriptome.Metagenome sequencing showed that there was no difference inαandβdiversity of mucosa-attached bacteria between day and treatment,but bacteria related to diarrhea were more abundant in the colon mucosa on D0 compared to D5.In addition,q PCR indicated that the absolute abundance of Escherichia coli(E.coli)decreased in the colon mucosa on D5 compared to D0;however,that of Bifidobacterium,Lactobacillus,and Faecalibacterium prausnitzii,which could competitively exclude E.coli,increased in the colon mucosa on D5 compared to D0.RNA-sequencing showed that there were no differentially expressed genes between CON and SCB,but suggested that pathways related to viral infection such as“Interferon Signaling”were activated in the colon mucosa of D5 compared to D0.Conclusions Growth affected mucosa-attached bacteria and host immune function in the colon mucosa during the first 5 d of life in dairy calves independently of SCB supplementation.During early life,opportunistic pathogens may decrease due to intestinal environmental changes by beneficial bacteria and/or host immune function.Predicted activation of immune function-related pathways may be the result of host immune function development or suggest other antigens in the intestine during early life.Further studies focusing on the other antigens and host immune function in the colon mucosa are required to better understand intestinal immune function development. 展开更多
关键词 Colon biopsy Dairy calves RNA-sequencing Saccharomyces cerevisiae boulardii 16S rRNA amplicon-sequencing
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The FRB-searching Pipeline of the Tianlai Cylinder Pathfinder Array
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作者 Zijie Yu Furen Deng +14 位作者 Shijie Sun Chenhui Niu Jixia Li Fengquan Wu Wei-Yang Wang Yougang Wang Shifan Zuo Lin Shu Jie Hao Xiaohui Liu Reza Ansari Ue-Li Pen Albert Stebbins Peter Timbie Xuelei Chen 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第8期113-132,共20页
This paper presents the design,calibration,and survey strategy of the Fast Radio Burst(FRB)digital backend and its real-time data processing pipeline employed in the Tianlai Cylinder Pathfinder Array.The array,consist... This paper presents the design,calibration,and survey strategy of the Fast Radio Burst(FRB)digital backend and its real-time data processing pipeline employed in the Tianlai Cylinder Pathfinder Array.The array,consisting of three parallel cylindrical reflectors and equipped with 96 dual-polarization feeds,is a radio interferometer array designed for conducting drift scans of the northern celestial semi-sphere.The FRB digital backend enables the formation of 96 digital beams,effectively covering an area of approximately 40 square degrees with the 3 dB beam.Our pipeline demonstrates the capability to conduct an automatic search of FRBs,detecting at quasi-realtime and classifying FRB candidates automatically.The current FRB searching pipeline has an overall recall rate of88%.During the commissioning phase,we successfully detected signals emitted by four well-known pulsars:PSR B0329+54,B2021+51,B0823+26,and B2020+28.We report the first discovery of an FRB by our array,designated as FRB 20220414A.We also investigate the optimal arrangement for the digitally formed beams to achieve maximum detection rate by numerical simulation. 展开更多
关键词 instrumentation interferometers-methods data analysis-(stars )pulsars general-telescopes
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矿井巷道无线传感器网络分层拓扑控制策略 被引量:19
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作者 周公博 朱真才 +1 位作者 陈光柱 周丽娟 《煤炭学报》 EI CAS CSCD 北大核心 2010年第2期333-337,共5页
根据矿井巷道的特点,以井下人员定位系统为背景,介绍了一种层次型无线传感器网络模型,提出了一种基于静态节点且可控部署的拓扑控制方法,并给出了网络节点布置的具体算法。在此基础上,研究了此网络模型的连通覆盖性,给出了满足人员定位... 根据矿井巷道的特点,以井下人员定位系统为背景,介绍了一种层次型无线传感器网络模型,提出了一种基于静态节点且可控部署的拓扑控制方法,并给出了网络节点布置的具体算法。在此基础上,研究了此网络模型的连通覆盖性,给出了满足人员定位系统连通覆盖性要求的约束条件,最后分析了此网络模型的能耗与路由跳数(hops)问题。结果表明,在一个被测节点通过监测区域的过程中,层次型无线传感器网络的系统总能耗与能耗方差约为节点均匀分布的单层链状网络的25%和33%,信息传递的路由跳数约为节点均匀分布的单层链状网络的1/3。 展开更多
关键词 无线传感器网络 拓扑控制 层次型 连通覆盖性 能耗
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基于栅格分层的逐栅格汇流算法并行化研究 被引量:8
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作者 刘军志 朱阿兴 +4 位作者 刘永波 秦承志 陈腊娇 吴辉 杨琳 《国防科技大学学报》 EI CAS CSCD 北大核心 2013年第1期123-129,共7页
分布式水文模型中的逐栅格汇流算法计算量大,需要借助并行计算以满足大流域长历时模拟的要求。针对目前鲜有对基于隐式有限差分的逐栅格汇流算法进行并行计算研究的情况,基于栅格分层的思想提出一种适用于共享内存并行计算环境的逐栅格... 分布式水文模型中的逐栅格汇流算法计算量大,需要借助并行计算以满足大流域长历时模拟的要求。针对目前鲜有对基于隐式有限差分的逐栅格汇流算法进行并行计算研究的情况,基于栅格分层的思想提出一种适用于共享内存并行计算环境的逐栅格汇流并行算法。该算法首先根据流向进行栅格分层,使同一层中栅格的计算相互独立,然后将同一层中栅格的计算任务分配到多个计算单元并行计算。采用C++编程语言与OpenMP并行编程库实现了该算法,并选择河北省清水河流域为实验区,在不同数据规模(30m、90m、270m分辨率)、不同核数(2~20个)以及不同栅格分层方法的情况下对算法性能进行了测试。实验结果表明本文提出的并行算法具有较好的加速比和并行效率,且并行效率随数据规模的增大而增大。栅格分层方法对算法并行性能有明显影响,从上到下的分层方法比从下到上的方法具有更高的并行效率。 展开更多
关键词 逐栅格汇流 隐式有限差分 栅格分层 并行计算 OPENMP
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利用分布有/无数据预测物种空间分布的研究方法综述! 被引量:14
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作者 刘芳 李晟 李迪强 《生态学报》 CAS CSCD 北大核心 2013年第22期7047-7057,共11页
详细的物种地理分布信息是生态学研究和制定保护策略的基础。相比较于直接估测种群数量,获取物种分布的有/无数据更为实用。因此,利用分布有/无数据并结合环境变量建立模型预测物种空间分布的方法在近年来得到了长足发展,并被广泛应用... 详细的物种地理分布信息是生态学研究和制定保护策略的基础。相比较于直接估测种群数量,获取物种分布的有/无数据更为实用。因此,利用分布有/无数据并结合环境变量建立模型预测物种空间分布的方法在近年来得到了长足发展,并被广泛应用。利用分布有/无数据预测物种分布,关键的步骤包括:1)构建总体概念模型,2)收集物种分布有/无数据,并准备环境变量图层;3)选择合适的统计模型和算法,以及4)对模型进行评估。概念模型提出研究假设,并确定数据收集及模型方法。收集物种分布数据有系统调查及非系统调查方法。筛选并准备与物种分布相关的环境变量,利用GIS工具处理,使之成为符合模型条件的具有合适的空间尺度的数字化图层。利用环境变量和物种分布有/无的数据,选择合适的方法及软件建立模型,并对模型进行检验和评估。总结了用于构建物种分布模型的不同算法和软件。针对以上各个环节,阐述利用物种分布有/无数据进行研究所需要的技术细节,以期望为读者提供借鉴。 展开更多
关键词 无数据 物种分布模型 取样 模型评估
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急性运动诱导大鼠骨骼肌线粒体生物合成:H2O2参与介导PGC-1α转录 被引量:4
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作者 丁虎 刘晓然 +4 位作者 刘丹霞 文立 刘树森 吉立力 张勇 《中国运动医学杂志》 CAS CSCD 北大核心 2008年第2期136-143,共8页
目的:线粒体产生的活性氧(ROS)是多种重要细胞信号转导通路的调节中心,本文拟探讨运动源性的过氧化氢(H2O2)是否作为信号分子参与了运动诱导的骨骼肌线粒体生物合成过程。方法:以大鼠急性递增负荷跑台运动为模型,连续观察和分别测定对照... 目的:线粒体产生的活性氧(ROS)是多种重要细胞信号转导通路的调节中心,本文拟探讨运动源性的过氧化氢(H2O2)是否作为信号分子参与了运动诱导的骨骼肌线粒体生物合成过程。方法:以大鼠急性递增负荷跑台运动为模型,连续观察和分别测定对照组(C),运动中45min、90min1、20min 150min(分别以E45、E90、E120和E150组表示)及运动后恢复3h、6h、12h、18h和24h(分别以R3h、R6h、R12h、R18h和R24h组表示)各时间点骨骼肌组织中H2O2浓度,PGC-1α、NRF-1、Tfam、COX IV mRNA表达,PGC-1α、Tfam、COX IV和p38MAPK蛋白含量以及p38MAPK活性的变化。结果:1)与对照组比较,E45组骨骼肌H2O2浓度即开始呈现显著性增加,并持续到R6h组(均P<0.001);在R12h组出现短暂降低后,又持续显著性增加至R24h组(均P<0.001);2)E150和R3h组PGC-1αmRNA表达与对照组相比显著增加(P<0.01和P<0.001);随后,R6h^R18h组PGC-1αmRNA表达降低(P>0.05),R24h组PGC-1α基因表达又呈现显著性增加(P<0.05)。PGC-1α蛋白含量滞后于其基因表达,在R6h和R12h组中显著增加(均P<0.001);3)R3h^R12h组骨骼肌NRF-1mRNA表达较对照组显著增加(P<0.01和P<0.001)。随后,NRF-1基因转录开始下降(P>0.05);4)除E150组外,从E90~R24h组的骨骼肌Tfam mRNA均较对照组显著增加(P<0.01和P<0.001)。E45和E90组的Tfam蛋白含量较对照组呈现短暂的显著增加(P<0.001),在E120组降低后又呈现显著性增加,直至R24h组(均P<0.001);5)E120组骨骼肌COX IV基因表达较对照组显著增加(P<0.05),恢复期R3h^R18h组呈显著性增加(均P<0.001)。运动中各组COX IV蛋白含量较对照组未呈现显著增加,但恢复期各时间段COX IV蛋白水平均呈显著性增加(均P<0.001);6)骨骼肌p38 MAPK活性(磷酸化p38 MAPK)在E90~R6h组,R18h^R24h组呈显著性增加(分别P<0.05、P<0.01和P<0.001)。仅R3h组p38 MAPK蛋白含量较对照组呈显著性增加(P<0.05)。结论:一次急性运动即可影响COX IV基因和蛋白表达,诱导骨骼肌线粒体生物合成;运动源性的H2O2可能通过先行激活p38MAPK磷酸化和继发诱导p38MAPK信号通路两个途径影响PGC-1α基因转录和线粒体生物合成的下游信号级联反应。 展开更多
关键词 H2O2 PGC-1Α 线粒体生物合成 骨骼肌 急性运动 大鼠
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线粒体移动相关基因miro1在急性运动中的表达特征 被引量:2
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作者 刘慧君 翟克敏 +5 位作者 赵斐 靳庆勋 齐海荣 刘洪涛 吉力立 张勇 《中国运动医学杂志》 CAS CSCD 北大核心 2010年第2期173-176,共4页
目的:探讨在急性运动中骨骼肌线粒体能量代谢与线粒体移动相关基因miro1的表达变化特征。方法:以C57 BL/6小鼠一次中等强度负荷跑台运动(0°,13m/min)为实验模型,将小鼠随机分为5组:安静对照组、运动30min、60min、90min、120min组... 目的:探讨在急性运动中骨骼肌线粒体能量代谢与线粒体移动相关基因miro1的表达变化特征。方法:以C57 BL/6小鼠一次中等强度负荷跑台运动(0°,13m/min)为实验模型,将小鼠随机分为5组:安静对照组、运动30min、60min、90min、120min组,分别测定骨骼肌线粒体呼吸控制比(RCR),ATP合成酶活性、骨骼肌H2O2生成量,并观察运动中骨骼肌miro1 mRNA表达变化。结果:(1)120分钟急性运动过程中miro1mRNA表达均较安静组显著升高,其中E30、E60、E90、E120组分别较安静组增高32.8%、107.6%、63.8%及44.8%;(2)运动中各时间点骨骼肌H2O2均较安静组显著升高,E30~E120组分别较安静组升高22.1%、26.7%、37.6%、33.7%;(3)E30组ATP合成酶活性与安静组比较明显增加,其余各组无明显变化;整个运动过程中线粒体呼吸控制比无显著变化。结论:急性运动中骨骼肌miro1 mRNA表达较安静时显著增加,可能利于促进线粒体呼吸和ATP合成,以应对细胞能量需求。 展开更多
关键词 急性运动 骨骼肌 线粒体移动相关基因miro1 能量代谢
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北太平洋副热带逆流区长Rossby波动力特性 被引量:12
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作者 刘秦玉 王韶霞 +1 位作者 刘征宇 杨海军 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2001年第z1期28-37,共10页
利用2.5层海洋模式分析了北太平洋副热带逆流(STCC)区波长在450-840 km之间的长Rossby波的动力特性.不考虑耗散时,STCC区域的长Rossby波是中性波,其快模态的周期是88-110 d,相速度为0.06-0.09 m/s,群速度几乎与相速度相同.弱耗散作用使... 利用2.5层海洋模式分析了北太平洋副热带逆流(STCC)区波长在450-840 km之间的长Rossby波的动力特性.不考虑耗散时,STCC区域的长Rossby波是中性波,其快模态的周期是88-110 d,相速度为0.06-0.09 m/s,群速度几乎与相速度相同.弱耗散作用使长Rossby波为弱衰减波,但几乎不影响其相速度与频率.观测的STCC区海平面高度(SSH)的准90d振荡对应长Rossby波的第一斜压模,"快"模态的波动振幅是"慢"模态的约5倍.准90d振荡存在的3个必要条件是:(1)第2层向西平均流取值为0.02-0.04m/s;(2)2个活动层的厚度超过480 m;(3)第2层的密度介于24.8-26.8之间.正因为北太平洋STCC区满足这3个条件,才在该海域出现SSH的准90d振荡.海面热通量的变化对快模态长Rossby波的传播特性影响不大,但对慢模态的传播特性有一定的影响. 展开更多
关键词 副热带逆流 长Rossby波 准90d振荡.
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概念性土壤侵蚀模型的建立及在紫色土小流域的应用 被引量:2
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作者 王平 朱阿兴 +1 位作者 蔡强国 刘慧平 《农业工程学报》 EI CAS CSCD 北大核心 2009年第12期80-87,I0042,共9页
概念性土壤侵蚀模型在描述流域基本过程的同时对参数要求较低,现有概念性模型中计算产沙所需参数主要靠律定或借鉴经验值。该文介绍了1个无需流域出口产沙量长序列观测资料来律定且能适用于研究流域的概念性土壤侵蚀模型。模型中引入了... 概念性土壤侵蚀模型在描述流域基本过程的同时对参数要求较低,现有概念性模型中计算产沙所需参数主要靠律定或借鉴经验值。该文介绍了1个无需流域出口产沙量长序列观测资料来律定且能适用于研究流域的概念性土壤侵蚀模型。模型中引入了分布式水文模型WetSpa Extension作为水文模块,结合流域内试验小区上建立的流量—产沙量经验关系计算侵蚀量,再结合泥沙输移比构建起产沙模块。通过在紫色土地区小流域的应用表明,模型能够得到较合理的流域出口产流量、产沙量以及侵蚀率的空间分布等模拟结果,在没有试验小区的邻近流域地区也具有推广性,且能作为评价水保措施效益的有力工具。该概念性模型对于流域出口泥沙资料稀少的地区具有很高的应用价值和协助流域管理的潜力。 展开更多
关键词 土壤 侵蚀 模型 概念性 水土保持 紫色土
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SWAT模型对高精度土壤信息的敏感性研究 被引量:14
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作者 李润奎 朱阿兴 +1 位作者 Peter C.Augello James E.Burt 《地球信息科学》 CSCD 2007年第3期72-78,90,共8页
土壤信息是SWAT模型的重要输入数据,通常认为,土壤信息的精度直接影响着模拟结果的准确性。本文以美国Brewery Creek流域(19.5km2)为例,在其他输入不变的情况下,通过比较不同精度土壤数据(美国农业部SSURGO土壤图与SoLIM方法获得的土壤... 土壤信息是SWAT模型的重要输入数据,通常认为,土壤信息的精度直接影响着模拟结果的准确性。本文以美国Brewery Creek流域(19.5km2)为例,在其他输入不变的情况下,通过比较不同精度土壤数据(美国农业部SSURGO土壤图与SoLIM方法获得的土壤图)的模拟径流,分析SWAT模型对高精度土壤信息的敏感性。应用结果显示,在模型的校正前后,两种土壤数据的径流模拟结果均近似,差别并不显著。这表明在小流域水文模拟中,SWAT模型的径流模拟对高精度土壤信息的敏感性较弱,模拟径流不能很好的体现一定精度基础上土壤信息的差别。本文将此现象主要归因于:SWAT模型所采用的SCS-CN径流计算方法,在计算CN值(Curve Number)时将不同土壤类型综合到四个土壤水文组的做法,概括了土壤信息,模糊了土壤之间的属性差别,损失了土壤精度信息。本研究发现了SCS-CN径流计算方法在利用高精度土壤数据时存在的问题,并进行了分析,为水文模拟中参数的确定和数据的准备提供了参考。 展开更多
关键词 SWAT SoLIM 土壤图 敏感性 CN值
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滑坡危险度制图精度评价指标的有效性研究 被引量:6
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作者 缪亚敏 朱阿兴 杨琳 《自然灾害学报》 CSCD 北大核心 2017年第2期115-122,共8页
对滑坡危险度制图进行精度评价具有重要意义。现有对滑坡危险度制图进行评价的研究多集中于评价指标的建立和应用,而评价指标能否有效地度量滑坡危险度图的精度、区分不同质量的滑坡危险度图尚值得研究。针对只使用正样本的评价指标,选... 对滑坡危险度制图进行精度评价具有重要意义。现有对滑坡危险度制图进行评价的研究多集中于评价指标的建立和应用,而评价指标能否有效地度量滑坡危险度图的精度、区分不同质量的滑坡危险度图尚值得研究。针对只使用正样本的评价指标,选择其中3种常用的非阈值依赖性评价指标——预报效率曲线及曲线下面积、P/E曲线及连续Boyce指数和空间聚集度作为精度评价标准,以甘肃省油坊沟流域为研究区,采用正样本和不同的负样本,基于随机森林模型推测生成不同质量的滑坡危险度图,应用3个评价指标对其进行精度评价,验证了各评价指标的有效性。结果发现,预报效率曲线与P/E曲线的分布可以体现不同质量的滑坡危险度图的差异,但是预报效率曲线下的面积只适宜于滑坡危险度高估时的制图精度评价,而连续Boyce指数与空间聚集度只适宜于滑坡危险度低估时的制图精度评价。 展开更多
关键词 评价指标 制图精度 滑坡危险度制图
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4种马铃薯淀粉糊流变特性的研究 被引量:7
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作者 柴春祥 Sundaram Gunasekaran 《食品与发酵工业》 CAS CSCD 北大核心 2007年第5期76-79,共4页
对4种不同加工方式获得的马铃薯淀粉糊流变特性进行了探讨。静态流变特性测定结果表明,4种淀粉糊的流变模型为幂率模型,均为假塑性流体,每种淀粉糊以相同方式流动需要施加的力不同。在相同流动方式下,淀粉4粘度最大,其次为淀粉2,淀粉1... 对4种不同加工方式获得的马铃薯淀粉糊流变特性进行了探讨。静态流变特性测定结果表明,4种淀粉糊的流变模型为幂率模型,均为假塑性流体,每种淀粉糊以相同方式流动需要施加的力不同。在相同流动方式下,淀粉4粘度最大,其次为淀粉2,淀粉1和淀粉3的粘度近似相同。动态流变特性测定结果表明:随着温度的增加,淀粉1、2、4的弹性模量、粘性模量刚开始基本不发生变化,到60℃后,两模量急剧增加到最大值,然后降低到某恒定值。淀粉3的两模量随温度升高逐渐增加到最大值,然后逐渐降低到某恒定值。粘性模量达到最大后,淀粉2的粘性模量最大,其次为淀粉4、淀粉1,淀粉3的最低。弹性模量达到最大后,淀粉4的弹性模量最大,其次为淀粉2、淀粉1,淀粉3最低。 展开更多
关键词 淀粉 粘度 弹性模量 粘性模量
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基于数据库驱动技术的土壤图注记自动配置系统的设计与实现 被引量:1
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作者 雷秋良 朱阿兴 +4 位作者 武淑霞 张认连 徐爱国 张维理 孙福军 《土壤学报》 CAS CSCD 北大核心 2018年第2期293-303,共11页
土壤注记是土壤图制图表达的重要内容,对于理解土壤的发生、分布具有重要意义。在基于全国第二次土壤普查资料进行大比例尺土壤图分幅制图过程中,若对拥有海量土壤空间信息的多分幅大比例尺土壤图实现注记表达,不可能再依赖于传统的制... 土壤注记是土壤图制图表达的重要内容,对于理解土壤的发生、分布具有重要意义。在基于全国第二次土壤普查资料进行大比例尺土壤图分幅制图过程中,若对拥有海量土壤空间信息的多分幅大比例尺土壤图实现注记表达,不可能再依赖于传统的制图方式生成注记。为了实现注记上图的自动化和以交互方式解决多个步骤判断问题,构建了土壤图注记自动配置系统。该系统采用图廓边界注记压盖检测与处理技术,解决了注记压盖图廓边界的问题;采用图层、分级码、要素对象的三级控制方法,实现了注记在图层级别上进行整个图层以及背景层注记的设置,在分级码级别上结合统计结果,实现了注记的条件判别与阈值过滤,在要素级别上实现了特殊要素注记的生成。基于数据库驱动技术并以人机交互的方式进行土壤图注记的自动化配置,实现了批量土壤图分幅注记的快速生成,不仅具有较强的灵活性,可适用于不同比例尺土壤图及其他类型地图的注记表达,而且大大提高了数据生产的效率和自动化处理程度。该研究为今后不同比例尺土壤图制图实现注记的自动化配置提供参考。 展开更多
关键词 土壤图 注记 自动配置 图层 分级码 要素 数据库驱动
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日本农业基本建设投资体系的演变、特征及其启示 被引量:5
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作者 毛世平 龚雅婷 《中国软科学》 CSSCI CSCD 北大核心 2017年第10期1-11,共11页
日本从20世纪下半叶开始构建并逐步完善其农业基本建设投资体系,为农业产业高效发展和农产品有效供给提供坚实的基础保障。由于日本与中国具有相似的农业资源禀赋,其农业基本建设投资体系值得我们学习和参考。本文首先探究了日本农业基... 日本从20世纪下半叶开始构建并逐步完善其农业基本建设投资体系,为农业产业高效发展和农产品有效供给提供坚实的基础保障。由于日本与中国具有相似的农业资源禀赋,其农业基本建设投资体系值得我们学习和参考。本文首先探究了日本农业基本建设投资体系的历史演变,然后梳理分析了其农业基本建设投资体系的现实特征,最后总结凝练出对我国农业基本建设投资的有益借鉴和启示。 展开更多
关键词 农业基本建设 投资体系 投资主体 日本
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