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东海内陆架泥质沉积反映的古环境演化 被引量:43
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作者 王可 郑洪波 +1 位作者 Maarten Prins 郑妍 《海洋地质与第四纪地质》 CAS CSCD 北大核心 2008年第4期1-10,共10页
通过对东海内陆架闽浙沿岸泥质沉积体的MD06-3040孔进行粒度及年代测试,重建了东海内陆架1万年以来的古环境。认为研究区的沉积环境曾发生过3次变化:孔深18·6m至底部(10~10.7kaBP)对应近滨环境;15·13~18.6m(7.1~10kaBP)为... 通过对东海内陆架闽浙沿岸泥质沉积体的MD06-3040孔进行粒度及年代测试,重建了东海内陆架1万年以来的古环境。认为研究区的沉积环境曾发生过3次变化:孔深18·6m至底部(10~10.7kaBP)对应近滨环境;15·13~18.6m(7.1~10kaBP)为过渡带环境;0~15.13m(0~7.1kaBP)是海侵结束后高海平面的浅海环境,自10kaBP以来东海沿岸流开始影响本区并不断输送河流来源物质,7kaBP起形成稳定的泥质沉积体。根据该孔沉积物的沉积速率与粒度组分特征,说明不能简单地应用平均粒径指示冬季风强度,在东海地区,不仅冬季风控制着沿岸流强度,夏季风也会影响河流入海物质的搬运沉积作用。 展开更多
关键词 全新世 古环境 粒度 东海
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柴北缘锡铁山花岗质片麻岩深熔作用年代和冷却历史:来自浅色体^(40)Ar/^(39)Ar年代学证据 被引量:4
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作者 胡荣国 邱华宁 +3 位作者 Jan R.WIJBRANS Fraukje M.BROUWER 何立言 王敏 《大地构造与成矿学》 EI CAS CSCD 北大核心 2016年第1期125-135,共11页
长英质浅色体广泛出露于柴北缘造山带中段锡铁山地体花岗质片麻岩中,多呈脉状、不规则透镜状顺区域片麻理走向产出,主要由钾长石、斜长石、角闪石、石英以及少量黑云母组成,是黑云母花岗质片麻岩深融作用的产物。温压估算获得其形成条件... 长英质浅色体广泛出露于柴北缘造山带中段锡铁山地体花岗质片麻岩中,多呈脉状、不规则透镜状顺区域片麻理走向产出,主要由钾长石、斜长石、角闪石、石英以及少量黑云母组成,是黑云母花岗质片麻岩深融作用的产物。温压估算获得其形成条件为P=(6.5~9.6)′102 MPa,T=640~690℃,达麻粒岩相。选取浅色体角闪石和钾长石单矿物进行激光阶段加热^(40)Ar/^(39)Ar定年。角闪石共进行了17个阶段,其中3~17阶段数据形成平坦年龄谱,坪年龄为442.5±4.0 Ma;构成年龄坪的数据对应的等时线年龄为441.6±3.9 Ma,相应初始捕获氩比值为303±4,暗示该角闪石样品不含过剩^(40)Ar。坪年龄~442.5 Ma解释为角闪石初始结晶年龄,代表了锡铁山地区黑云母片麻岩发生深融(混合岩化)的时代。共生钾长石阶段加热获得一个低温和一个高温坪,坪年龄分别为307.5±2.9 Ma和323.3±3.0 Ma;等时线图谱暗示该钾长石样品未受过剩^(40)Ar干扰。坪年龄分别代表浅色体冷却到钾长石封闭温度~200℃和~250℃的时间。^(40)Ar/^(39)Ar定年结果显示锡铁山黑云母片麻岩深熔作用后经历了低速抬升(0.1~0.2 km/Ma)和缓慢冷却(3~3.6℃/Ma)的演化历史。 展开更多
关键词 浅色体 花岗质片麻岩 深熔作用 40Ar/39Ar定年 冷却历史 锡铁山地体
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柴北缘锡铁山榴辉岩退变质成因角闪石^40Ar/^39Ar年代学研究 被引量:6
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作者 胡荣国 王敏 +2 位作者 Jan R WIJBRANS Fraukje M BROUWER 邱华宁 《岩石学报》 SCIE EI CAS CSCD 北大核心 2013年第9期3031-3038,共8页
采用激光阶段加热^40Ar/^39Ar技术,对柴达木盆地北缘锡铁山榴辉岩退变质作用形成的榴闪岩和斜长角闪岩之角闪石进行了定年分析。09NQ44Amp来自榴闪岩,各阶段表观年龄(以现代空气氩^40Ar/^36Ar比值295.5扣除非放射性成因^40Ar)构成了... 采用激光阶段加热^40Ar/^39Ar技术,对柴达木盆地北缘锡铁山榴辉岩退变质作用形成的榴闪岩和斜长角闪岩之角闪石进行了定年分析。09NQ44Amp来自榴闪岩,各阶段表观年龄(以现代空气氩^40Ar/^36Ar比值295.5扣除非放射性成因^40Ar)构成了单调下降的阶梯状年龄谱。在反等时线图解上,2~4阶段数据点和5~18阶段数据点分别构成了两条等时线,等时年龄分别为427.6±10Ma和425.1±2.6Ma,对应的初始40Ar/36Ar比值则分别为435.2±6.1和705.3±13。角闪石09NQ43Amp来自榴辉岩强烈退变质作用形成的斜长角闪岩,40Ar/39Ar阶段加热分析也获得单调下降的年龄谱,在反等时线图解上其数据点3~6阶段和7~16阶段分别构成了两条等时线,等时年龄分别为418.9±2.9Ma和418.1±2.1Ma,对应的初始40Ar/36Ar比值则分别为493.7±2.8和685.8±34.3。等时线截距值高于现代大气40Ar/36Ar比值,表明角闪石中含过剩40Ar。同时,由低温和中-高温阶段加热数据点分别构成两条等时年龄基本一致,截距值却明显不同的等时线,表明在角闪石热力学性质不同的源区,存在两期明显不同且未混合的初始捕获Ar组分。等时年龄425~418Ma代表的是锡铁山榴辉岩角闪岩相退变质作用发生的时间。等时线图解法虽然有效的校正了角闪石中的过剩40Ar,但仅根据表观年龄图谱和等时线图谱还无法清晰判断过剩40Ar在角闪石中的赋存状态,有待进一步探讨。 展开更多
关键词 40Ar/39Ar法 捕获Ar 角闪石 激光阶段加热 等时线图解
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柴北缘鱼卡多硅白云母40Ar/39Ar年代学研究及其外来40Ar来源探讨 被引量:2
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作者 胡荣国 邱华宁 +2 位作者 Jan WIJBRANS Fraukje BROUWER 王敏 《地学前缘》 EI CAS CSCD 北大核心 2014年第1期216-227,共12页
采用激光阶段加热40Ar/39Ar定年技术,选取柴北缘超高压变质带鱼卡地体超高压变质岩及其围岩的6个多硅白云母进行了Ar同位素分析,获得丰富年代学数据。榴辉岩和云母斜长角闪岩多硅白云母具有高Si、高Mg含量的特征,阶段加热给出复杂的表... 采用激光阶段加热40Ar/39Ar定年技术,选取柴北缘超高压变质带鱼卡地体超高压变质岩及其围岩的6个多硅白云母进行了Ar同位素分析,获得丰富年代学数据。榴辉岩和云母斜长角闪岩多硅白云母具有高Si、高Mg含量的特征,阶段加热给出复杂的表观年龄图谱,总气体年龄(708~534 Ma)和等时年龄(681~513Ma)都明显老于区内榴辉岩锆石U-Pb年龄,暗示样品含大量外来40Ar。相比之下,围岩花岗质片麻岩和白云母石英片岩多硅白云母具有相对低Si高Fe的特征,阶段加热给出平坦的40Ar/39Ar年龄谱,对应坪年龄分别为454和418Ma。构成年龄坪的数据点形成了线性关系良好的反等时线,并获得同坪年龄一致的等时年龄,能与区域地质年龄很好地吻合。坪年龄454Ma解释为花岗质片麻岩冷却到约400℃时的时间,同时也代表了鱼卡变质岩在经历了深俯冲超高压变质作用后,从上地幔折返抬升至中-上地壳深度的时限;片岩多硅白云母坪年龄418Ma纪录的则是区内一次强韧性剪切事件发生的时代。考虑到榴辉岩和斜长角闪岩原岩为变基性玄武岩类,其主要含钾矿物角闪石的Ar封闭稳定性较高,同时在超高压变质过程中,它们处在一个相对封闭和缺乏流体活动的极端地质环境,所以认为鱼卡榴辉岩多硅白云母外来40Ar来自原岩而非后期渗入的流体,属于"继承"40Ar的范畴。 展开更多
关键词 外来40Ar 继承40Ar 多硅白云母 鱼卡地体 超高压变质岩
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6种草本植物对干旱胁迫和CO_2浓度升高交互作用的生长响应 被引量:17
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作者 高凯敏 刘锦春 +2 位作者 梁千慧 Andries A.Temme Johannes H.C.Cornelissen 《生态学报》 CAS CSCD 北大核心 2015年第18期6110-6119,共10页
以CO2浓度升高为主要标志的全球气候变化及由其引起的极端气候变化对陆地生态系统产生了重要的影响。利用步入式CO2生长室模拟研究了CO2浓度变化(400和700μL/L)和干旱胁迫(水分充足CK:100%FC(田间持水量);中度干旱MS:40%FC;重度干旱SS:... 以CO2浓度升高为主要标志的全球气候变化及由其引起的极端气候变化对陆地生态系统产生了重要的影响。利用步入式CO2生长室模拟研究了CO2浓度变化(400和700μL/L)和干旱胁迫(水分充足CK:100%FC(田间持水量);中度干旱MS:40%FC;重度干旱SS:20%FC)的交互作用对草本植物网果酸模(Rumex chalepensis)、野豌豆(Vicia sepium)、泥胡菜(Hemmistepta lyrata)、风轮菜(Clinopodium chinense)、藜(Chenopodium album)和玉米石(Sedum album)生长特性的影响。结果表明:CO2浓度升高总体上刺激了网果酸模、野豌豆、泥胡菜、风轮菜和藜这5种C3植物在任何水分条件下的生长,也刺激了玉米石在水分条件较好下的生长;干旱胁迫总体上抑制了所有6种植物的生长,但中度干旱胁迫有刺激CAM植物玉米石生长的趋势。CO2浓度升高能否缓解干旱的负面影响具有明显的种间差异:CO2浓度升高减缓了干旱胁迫对泥胡菜和风轮菜的负面影响,这种缓解作用在网果酸模和野豌豆中显著降低,对藜没有明显的促进作用,对干旱下的玉米石的生长却起到了抑制作用。CO2浓度升高总体上增加了根质量分数和干物质含量;干旱胁迫明显提高了6种草本植物的根生物量的分配比例,降低了干物质含量;但CO2浓度升高和干旱胁迫的交互作用可导致不同的物种产生不同的响应,说明植物能够通过调节生物量分配和植株本身的水分含量保持能力来适应CO2浓度和干旱胁迫的交互影响,这种调节能力取决于植物在碳的吸收和水分散失之间的平衡"trade-off"。研究结果有助于增进草本植物对未来气候变化的适应性理解,为评估和预测全球气候和水文变化对植物的生理生态影响提供理论依据。 展开更多
关键词 CO2浓度升高 干旱胁迫 生物量分配 草本植物 田间持水量(FC)
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渭河流域沉积物碎屑锆石U-Pb年龄物源示踪 被引量:3
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作者 张笑宇 何梦颖 +2 位作者 王斌 D S RITS 郑洪波 《海洋地质与第四纪地质》 CAS CSCD 北大核心 2018年第1期202-211,共10页
渭河盆地是秦岭山前新生代陆内断陷盆地,接受大量秦岭造山带的沉积。建立渭河盆地沉积物物源示踪体系,对了解渭河盆地和秦岭的盆山耦合关系及其周缘构造-沉积演化均具有重要的意义。对渭河流域干流及主要支流沉积物进行碎屑锆石U-Pb年... 渭河盆地是秦岭山前新生代陆内断陷盆地,接受大量秦岭造山带的沉积。建立渭河盆地沉积物物源示踪体系,对了解渭河盆地和秦岭的盆山耦合关系及其周缘构造-沉积演化均具有重要的意义。对渭河流域干流及主要支流沉积物进行碎屑锆石U-Pb年龄测试。结果表明:渭河干流沉积物碎屑锆石主要呈现五组年龄区间,分别为100~300、300~500、700~1000、1700~2000和2100~2500 Ma,其中以100~300 Ma和300~500 Ma的锆石为主,判别渭河干流沉积物主要来自北秦岭造山带。渭河上游与中下游沉积物在1700~2000 Ma和2100~2500 Ma的年龄组成存在差异,主要与上游出露的元古代岩体相关。渭河支流沉积物碎屑锆石年龄分布存在显著差异。泾河和洛河流经黄土高原,沉积物碎屑锆石U-Pb年龄与黄土高原相似,主要表现为200~300、400~500、800~1100、1800~2000和2400~2550 Ma五组年龄;灞河沉积物继承了北秦岭造山带的特征。通过对渭河流域沉积物的物源分析可知:泾河对渭河干流沉积物贡献较大,灞河对渭河干流沉积物贡献较小,洛河对渭河干流沉积物有一定贡献。渭河汇入黄河前后,黄河沉积物碎屑锆石年龄峰分布及各年龄区间锆石含量比例有明显变化,反映渭河对黄河沉积物有较大影响。 展开更多
关键词 渭河沉积物 碎屑锆石U-Pb定年 物源示踪 渭河盆地
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6种草本植物对“过去-现在-未来”CO_2浓度的生长响应 被引量:4
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作者 梁千慧 刘锦春 +1 位作者 高凯敏 Johannes H.C.Cornelissen 《西南大学学报(自然科学版)》 CAS CSCD 北大核心 2017年第1期61-68,共8页
以6种草本植物泥胡菜Hemistepta lyrata,网果酸模Rumex chalepensis,野豌豆Vicia Sepium,藜Chenopodium album,风轮菜Clinopodium chinense和玉米石Sedum album为研究对象,利用步入式CO_2浓度控制生长室模拟研究了"过去(150μmol/m... 以6种草本植物泥胡菜Hemistepta lyrata,网果酸模Rumex chalepensis,野豌豆Vicia Sepium,藜Chenopodium album,风轮菜Clinopodium chinense和玉米石Sedum album为研究对象,利用步入式CO_2浓度控制生长室模拟研究了"过去(150μmol/mol)-现在(400μmol/mol)-将来(700μmol/mol)"CO_2浓度对植物生长特性的影响.结果表明:CO_2浓度升高刺激了6种植物的总生物量和相对生长速率,但CO_2浓度从过去的低浓度升高到目前浓度水平时,其升高幅度大于CO_2浓度从目前浓度升高到将来浓度水平.在过去水平下CO_2浓度升高刺激了6种植物的根质量分数,但将来水平下CO_2浓度升高对6种植物的根质量分数没有产生显著性影响.研究结果表明植物对过去CO_2浓度的适应性响应会抑制植物对将来CO_2浓度的生长响应,但不同物种之间存在差异.该研究结果有助于理解草本植物在未来气候变化下的响应,为评估和预测全球气候变化对植物的生理生态影响提供理论依据. 展开更多
关键词 CO2浓度 生物量 相对生长速率 进化 全球气候变化
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How Could Agricultural Land Systems Contribute to Raise Food Production Under Global Change? 被引量:22
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作者 WU Wen-bin YU Qiang-yi +3 位作者 Verburg H Peter YOU Liang-zhi YANG Peng TANG Hua-jun 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2014年第7期1432-1442,共11页
To feed the increasing world population, more food needs to be produced from agricultural land systems. Solutions to produce more food with fewer resources while minimizing adverse environmental and ecological consequ... To feed the increasing world population, more food needs to be produced from agricultural land systems. Solutions to produce more food with fewer resources while minimizing adverse environmental and ecological consequences require sustainable agricultural land use practices as supplementary to advanced biotechnology and agronomy. This review paper, from a land system perspective, systematically proposed and analyzed three interactive strategies that could possibly raise future food production under global change. By reviewing the current literatures, we suggest that cropland expansion is less possible amid iferce land competition, and it is likely to do less in increasing food production. Moreover, properly allocating crops in space and time is a practical way to ensure food production. Climate change, dietary shifts, and other socio-economic drivers, which would shape the demand and supply side of food systems, should be taken into consideration during the decision-making on rational land management in respect of sustainable crop choice and allocation. And ifnally, crop-speciifc agricultural intensiifcation would play a bigger role in raising future food production either by increasing the yield per unit area of individual crops or by increasing the number of crops sown on a particular area of land. Yet, only when it is done sustainably is this a much more effective strategy to maximize food production by closing yield and harvest gaps. 展开更多
关键词 agricultural land systems food production expansion ALLOCATION INTENSIFICATION global change
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Spatio-Temporal Changes in the Rice Planting Area and Their Relationship to Climate Change in Northeast China: A Model-Based Analysis 被引量:14
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作者 XIA Tian WU Wen-bin +5 位作者 ZHOU Qing-bo YU Qiang-yi Peter H Verburg YANG Peng LU Zhong-jun TANG Hua-jun 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2014年第7期1575-1585,共11页
Rice is one of the most important grain crops in Northeast China (NEC) and its cultivation is sensitive to climate change. This study aimed to explore the spatio-temporal changes in the NEC rice planting area over t... Rice is one of the most important grain crops in Northeast China (NEC) and its cultivation is sensitive to climate change. This study aimed to explore the spatio-temporal changes in the NEC rice planting area over the period of 1980-2010 and to analyze their relationship to climate change. To do so, the CLUE-S (conversion of land use and its effects at small region extent) model was ifrst updated and used to simulate dynamic changes in the rice planting area in NEC to understand spatio-temporal change trends during three periods: 1980-1990, 1990-2000 and 2000-2010. The changing results in individual periods were then linked to climatic variables to investigate the climatic drivers of these changes. Results showed that the NEC rice planting area expanded quickly and increased by nearly 4.5 times during 1980-2010. The concentration of newly planted rice areas in NEC constantly moved northward and the changes were strongly dependent on latitude. This conifrmed that climate change, increases in temperature in particular, greatly inlfuenced the shift in the rice planting area. The shift in the north limit of the NEC rice planting area generally followed a 1&#176;C isoline migration pattern, but with an obvious time-lag effect. These ifndings can help policy makers and crop producers take proper adaptation measures even when exposed to the global warming situation in NEC. 展开更多
关键词 spatio-temporal change rice planting area climate change Northeast China
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远程耦合世界的可持续性框架 被引量:19
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作者 刘建国 Vanessa Hull +20 位作者 Mateus Batistella Ruth DeFries Thomas Dietz 付峰 Thomas W.Hertel R.Cesar Izaurralde Eric F.Lambin 李舒心 Luiz A.Martinelli William J.McConnell Emilio F.Moran Rosamond Naylor 欧阳志云 KarenR.Polenske Anette Reenberg Gilberto de Miranda Rocha Cynthia S.Simmons Peter H.Verburg Peter M.Vitousek 张福锁 朱春全 《生态学报》 CAS CSCD 北大核心 2016年第23期7870-7885,共16页
远距离之间的相互作用及其影响日益广泛。这种远程相互作用往往会对可持续发展产生深远的影响并会造成意想不到的结果。很多可持续性研究都是针对某个特定地点进行的,很少注重多个地点之间远程相互作用对可持续性所产生的影响。虽然有... 远距离之间的相互作用及其影响日益广泛。这种远程相互作用往往会对可持续发展产生深远的影响并会造成意想不到的结果。很多可持续性研究都是针对某个特定地点进行的,很少注重多个地点之间远程相互作用对可持续性所产生的影响。虽然有些研究涉及到远程因素,但通常都把它们看作外在变量,而未把它们看作反馈。为了更好地理解和综合各种远程相互作用,本文提出了一种基于远程耦合的综合框架,它是一个远距离社会经济和环境相互作用的总体概念。人类与自然耦合系统是研究在特定地点发生的相互作用,远程耦合概念是对人类与自然耦合系统研究的自然延伸。远程耦合框架包括五个相关的组成部分,即:人类与自然耦合系统、流、代理、原因、和影响。本文通过农产品贸易和物种入侵两个远程相互作用的例子来解释远程耦合框架,重点阐述远程耦合框架的影响,并讨论促进远程耦合研究发展的研究条件和方法。这个框架有助于分析系统内各组成部分以及它们之间的相互关系,找出研究差距,探索其中的隐含成本以及尚未开发的优势,提供引入反馈及多系统(发送、接收和外溢系统)之间权衡和协同的有效手段,从本地到全球各个层面加深对远程相互作用的认识,并提高社会经济和环境可http://www.ecologica.cn持续发展政策的有效性。 展开更多
关键词 代理 原因 人类与环境耦合系统 人类与自然耦合系统 社会与生态耦合系统 扩散 远程相互作用 影响 反馈 全球化 投资 知识传播 迁移 社会经济与环境相互作用 物种入侵 可持续性 技术转让 远程连接 远程耦合 贸易 跨国土地交易 水转移
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Interpretation of Climate Change and Agricultural Adaptations by Local Household Farmers: a Case Study at Bin County, Northeast China 被引量:9
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作者 YU Qiang-yi WU Wen-bin +6 位作者 LIU Zhen-huan Peter H Verburg XIA Tian YANG Peng LU Zhong-jun YOU Liang-zhi TANG Hua-jun 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2014年第7期1599-1608,共10页
Although climate change impacts and agricultural adaptations have been studied extensively, how smallholder farmers perceive climate change and adapt their agricultural activities is poorly understood. Survey-based da... Although climate change impacts and agricultural adaptations have been studied extensively, how smallholder farmers perceive climate change and adapt their agricultural activities is poorly understood. Survey-based data (presents farmers' personal perceptions and adaptations to climate change) associated with external biophysical-socioeconomic data (presents real-world climate change) were used to develop a farmer-centered framework to explore climate change impacts and agricultural adaptations at a local level. A case study at Bin County (1980s-2010s), Northeast China, suggested that increased annual average temperature (0.6&#176;C per decade) and decreased annual precipitation (46 mm per decade, both from meteorological datasets) were correctly perceived by 76 and 66.9%, respectively, of farmers from the survey, and that a longer growing season was conifrmed by 70%of them. These reasonably correct perceptions enabled local farmers to make appropriate adaptations to cope with climate change:Longer season alternative varieties were found for maize and rice, which led to a signiifcant yield increase for both crops. The longer season also affected crop choice:More farmers selected maize instead of soybean, as implicated from survey results by a large increase in the maize growing area. Comparing warming-related factors, we found that precipitation and agricultural disasters were the least likely causes for farmers' agricultural decisions. As a result, crop and variety selection, rather than disaster prevention and infrastructure improvement, was the most common ways for farmers to adapt to the notable warming trend in the study region. 展开更多
关键词 perception adaptation survey climate change agriculture
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Retrograde metamorphism of the eclogite in North Qaidam,western China:Constraints by joint ^(40)Ar/^(39)Ar in vacuo crushing and stepped heating 被引量:4
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作者 Rongguo Hu Jan Wijbrans +3 位作者 Fraukje Brouwer Linghao Zhao Min Wang Huaning Qiu 《Geoscience Frontiers》 SCIE CAS CSCD 2015年第5期759-770,共12页
Two amphiboles and a syn-metamorphic quartz vein from the Yuka terrane,North Qaidam,western China,have been analyzed by joint40Ar/39Ar crushing in vacuo and stepwise heating techniques.The crushing in vacuo results pr... Two amphiboles and a syn-metamorphic quartz vein from the Yuka terrane,North Qaidam,western China,have been analyzed by joint40Ar/39Ar crushing in vacuo and stepwise heating techniques.The crushing in vacuo results provide information to directly constrain the timing of fluid activity and the age of amphibolite-facies retrogression.The stepwise heating results could further be used to decipher the thermal history of the UHP rocks.Amphiboles from amphibolites and quartz vein within garnetamphibolite lens analyzed by in vacuo crushing yield similarly shaped age spectra and exhibit relatively flat age plateaus for the last several steps.The characteristics of gas release patterns and geochronological data testify to the presence of significant excess40Ar within the fluid inclusions.The age plateaux with weighted mean ages(WMA) ranges from 488 to 476 Ma for amphiboles and 403 Ma for quartz(2σ).These data points constitute amphibole WMA yielding excellent isochrons with isochron ages of 469 and 463 Ma with initial40Ar/36Ar ratios of 520 and 334,respectively.The isochron ages are interpreted to represent initial amphibolite-facies retrogression.The data points constituting the quartz age plateaux give an isochron age of 405 Ma with initial40Ar/36Ar ratio of 295,recording a significant aqueous fluid flow episode during the early Devonian.Age spectra obtained by stepwise heating of amphibole residues remaining after crushing experiments are characterized by younger and relatively complex age spectra,which are probably influenced by the combined effects of resetting argon and/or mineral inclusions.Nevertheless,we note that the spectra shapes have features in common:excluding the last two steps,minimum apparent ages are found at temperatures of around 500 ℃,corresponding to319 and 249 Ma,perhaps representing the time of isotopic resetting or resulting from release gas from mineral inclusions of,e.g.,biotite or feldspar.Maximum apparent ages are obtained at temperatures of around 800℃,corresponding to 418 and 413 Ma,which probably reflect mixed ages of radiogenic resetting and original amphibole.These results indicate that the Yuka eclogites and their retrogressed equivalents were overprinted by multiple thermal events in the Silurian and possibly as young as the Triassic. 展开更多
关键词 40Ar/39Ar techniques In vacuo crushing AMPHIBOLITE
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Distribution and Forming Model of Fluvial Terrace in the Huangshui Catchment and its Tectonic Indication 被引量:3
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作者 WANG Xianyan LU Huayu +2 位作者 Jef VANDENBERGHE CHEN Zhongyan LI Langpin 《Acta Geologica Sinica(English Edition)》 SCIE CAS CSCD 2010年第2期415-423,共9页
The Huang Shui River, a main tributary of the Yellow River, crosses a series of tectonically subsided and uplifted areas that show different patterns of terrace formation. The distribution of fluvial terrace of the Hu... The Huang Shui River, a main tributary of the Yellow River, crosses a series of tectonically subsided and uplifted areas that show different patterns of terrace formation. The distribution of fluvial terrace of the Huang Shui River is studied through topographic and sedimentologic terrace mapping. Three terraces in the Haiyan Basin, four terraces in the Huangyuan Basin, 19 terraces in the Xi'ning Basin (the four high terraces may belong to another river), nine terraces in the Ping'an Basin, five terraces in the Ledu Basin and 12 terraces in the Minhe Basin are recognized. Sedimentology research shows that the geomorphologic and sedimentological pattern of the Huang Shui River, which is located at the margin of Tibet, are different from that of the rivers at other regions. The formation process of the terrace is more complicated at the Huang Shui catchment: both accumulation terrace and erosion terrace were formed in each basin and accumulation terraces were developed in some basins when erosion terraces were formed in other basins, indicating fluvial aggradation may occur in some basins simultaneously with river incision in other basins. A conceptual model of the formation process of these two kinds of fluvial terraces at Huang Shui catchment is brought forward in this paper. First, the equilibrium state of the river is broken because of climatic change and/or tectonic movement, and the river incises in all basins in the whole catchment until reaching a new equilibrium state. Then, the downstream basin subsides quickly and the equilibrium state is broken again, and the river incises at upstream basins while the river accumulates at the subsidence basin quickly until approaching a new equilibrium state again. Finally, the river incises in the whole catchment because of climatic change and/or tectonic movement and the accumulation terrace is formed at the subsidence basin while the erosion terrace is formed at other basins. The existence of the accumulation terrace implied the tectonic subsidence in the sub-basins in Huang Shui catchment. These tectonic subsidence movements gradually developed from the downstream Minhe Basin to the upstream Huangyuan Basin. Dating the terrace sequence has potential to uncover the relationship between the subsidence in the catchment and the regional tectonic at the northeastern Tibetan Plateau. 展开更多
关键词 Huangshui catchment fluvial terrace tectonic subsidence geomorphologic evolution late Cenozoic
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Interleukin-1βinduces human cementoblasts to support osteoclastogenesis 被引量:5
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作者 nam c-n huynh vincent everts +1 位作者 prasit pavasant ruchanee s ampornaramveth 《International Journal of Oral Science》 SCIE CAS CSCD 2017年第4期216-223,共8页
Injury of the periodontium followed by inflammatory response often leads to mot resorption. Resorption is accomplished by osteoclasts and their generation may depend on an interaction with the cells in direct contact ... Injury of the periodontium followed by inflammatory response often leads to mot resorption. Resorption is accomplished by osteoclasts and their generation may depend on an interaction with the cells in direct contact with the root, the cementoblasts. Our study aimed to investigate the role of human cementoblasts in the formation of osteoclasts and the effect of interleukin (IL)- 1β hereupon. Extracted teeth from healthy volunteers were subjected to sequential digestion by type I collagenase and trypsin. The effect of enzymatic digestion on the presence of cells on the root surface was analyzed by histology. Gene expression of primary human cementoblasts (pHCB) was compared with a human cementoblast cell line (HCEM). The pHCBs were analyzed for their expression of IL-1 receptors as well as of receptor activator of nuclear factor kappa-B ligand (RANKL) and osteoprotegerin (OPG). In a co-culture system consisting of osteoclast precursors (blood monocytes) and pHCBs, the formation of osteoclasts and their resorptive activity was assessed by osteo-assay and ivory slices. The cells obtained after a 120 min enzyme digestion expressed the highest level of bone sialoprotein, similar to that of HCEM. This fraction of isolated cells also shared a similar expression pattern of IL-1 receptors (ILl-R1 and ILl-R2). Treatment with IL-11~ potently upregulated RANKL expression but not of OPG. pHCBs were shown to induce the formation of functional osteoclasts. This capacity was significantly stimulated by pretreating the pHCBs with IL-1β prior to their co-culture with human blood monocytes. Our study demonstrated that cementoblasts have the capacity to induce osteoclastogenesis, a capacity strongly promoted by IL-1β. These results may explain why osteoclasts can be formed next to the root of teeth. 展开更多
关键词 cementoblast interleukin-ll3 OSTEOCLAST receptor activator of nuclear factor kappa-B ligand tooth resorption
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Neural plasticity and adult neurogenesis: the deep biology perspective 被引量:3
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作者 Anna Maria Colangelo Giovanni Cirillo +2 位作者 Lilia Alberghina Michele Papa Hans V.Westerhoff 《Neural Regeneration Research》 SCIE CAS CSCD 2019年第2期201-205,共5页
The recognition that neurogenesis does not stop with adolescence has spun off research towards the reduction of brain disorders by enhancing brain regeneration. Adult neurogenesis is one of the tougher problems of dev... The recognition that neurogenesis does not stop with adolescence has spun off research towards the reduction of brain disorders by enhancing brain regeneration. Adult neurogenesis is one of the tougher problems of developmental biology as it requires the generation of complex intracellular and pericellular anatomies, amidst the danger of neuroinflammation. We here review how a multitude of regulatory pathways optimized for early neurogenesis has to be revamped into a new choreography of time dependencies. Distinct pathways need to be regulated, ranging from neural growth factor induced differentiation to mitochondrial bioenergetics, reactive oxygen metabolism, and apoptosis. Requiring much Gibbs energy consumption, brain depends on aerobic energy metabolism, hence on mitochondrial activity. Mitochondrial fission and fusion, movement and perhaps even mitoptosis, thereby come into play. All these network processes are interlinked and involve a plethora of molecules. We recommend a deep thinking approach to adult neurobiology. 展开更多
关键词 NEUROGENESIS adult brain NEUROREGENERATION neuron differentiation nerve growth factor energy homeostasis mitochondria deep biology systems biology
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The evidence for the impact of policy on physical activity outcomes within the school setting: A systematic review 被引量:1
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作者 Catherine B.Woods Kevin Volf +7 位作者 Liam Kelly Blathın Casey Peter Gelius Sven Messing Sarah Forberger Jeroen Lakerveld Joanna Zukowska Enrique Garcıa Bengoechea 《Journal of Sport and Health Science》 SCIE 2021年第3期263-276,F0003,共15页
Background:Despite the well-established health benefits of physical activity(PA)for young people(aged 419 years),most do not meet PA guidelines.Policies that support PA in schools may be promising,but their impact on ... Background:Despite the well-established health benefits of physical activity(PA)for young people(aged 419 years),most do not meet PA guidelines.Policies that support PA in schools may be promising,but their impact on PA behavior is poorly understood.The aim of this systematic review was to ascertain the level and type of evidence reported in the international scientific literature for policies within the school setting that contribute directly or indirectly to increasing PA.Methods:This systematic review is compliant with Preferred Reporting Items for Systematic Review and Meta-Analysis guidelines.Six databases were searched using key concepts of policy,school,evaluation,and PA.Following title and abstract screening of 2323 studies,25 progressed to data synthesis.Methodological quality was assessed using standardized tools,and the strength of the evidence of policy impact was described based on pre-determined codes:positive,negative,inconclusive,or untested statistically.Results:Evidence emerged for 9 policy areas that had a direct or indirect effect on PA within the school setting.These were whole school PA policy,physical education,sport/extracurricular PA,classroom-based PA,active breaks/recess,physical environment,shared use agreements,active school transport,and surveillance.The bulk of the evidence was significantly positive(54%),27%was inconclusive,9%was significantly negative,and 11%was untested(due to rounding,some numbers add to 99%or 101%).Frequency of evidence was highest in the primary setting(41%),34%in the secondary setting,and 24%in primary/secondary combined school settings.By policy area,frequency of evidence was highest for sport/extracurricular PA(35%),17%for physical education,and 12%for whole school PA policy,with evidence for shared use agreements between schools and local communities rarely reported(2%).Comparing relative strength of evidence,the evidence for shared use agreements,though sparse,was 100%positive,while 60%of the evidence for whole school PA policy,59%of the evidence for sport/extracurricular PA,57%of the evidence for physical education,50%of the evidence for PA in classroom,and 50%of the evidence for active breaks/recess were positive.Conclusion:The current evidence base supports the effectiveness of PA policy actions within the school setting but cautions against a“one-sizefits-all”approach and emphasizes the need to examine policy implementation to maximize translation into practice.Greater clarity regarding terminology,measurement,and methods for evaluation of policy interventions is needed. 展开更多
关键词 Evaluation Physical activity POLICY SCHOOL Systematic review
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Clinical outcomes of patients with duodenal adenocarcinoma and intestinal-type papilla of Vater adenocarcinoma 被引量:1
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作者 Laura L Meijer Marin Strijker +10 位作者 Jacob K de Bakker Jurgen GJ Toennaer Barbara M Zonderhuis Hans J van der Vliet Hanneke Wilmink Joanne Verheij Freek Daams Olivier R Busch Nicole CT van Grieken Marc G Besselink Geert Kazemier 《World Journal of Gastrointestinal Oncology》 SCIE CAS 2020年第3期347-357,共11页
BACKGROUND Duodenal adenocarcinoma(DA)and intestinal-type papilla of Vater adenocarcinoma(it-PVA)are rare malignancies of the gastrointestinal tract.Current therapeutic options are translated nowadays from treatment s... BACKGROUND Duodenal adenocarcinoma(DA)and intestinal-type papilla of Vater adenocarcinoma(it-PVA)are rare malignancies of the gastrointestinal tract.Current therapeutic options are translated nowadays from treatment strategies for patients with colorectal cancer due to histopathological similarities.AIM To retrospectively investigate the clinical outcome of patients with DA and it-PVA.METHODS All patients with DA and it-PVA diagnosed between 2000 and 2017 were included at two academic centers in the Netherlands.All patients with histopathologically-confirmed DA or it-PVA were eligible for inclusion.Clinical outcome was compared between DA and it-PVA per disease stage.In the subgroup of stage IV disease,survival after local treatment of oligometastases was compared with systemic therapy or supportive care.RESULTS In total,155 patients with DA and it-PVA were included.Patients with it-PVA more often presented with stage I disease,while DA was more often diagnosed at stage IV(P<0.001).Of all patients,79%were treated with curative intent.The median survival was 39 mo,and no difference in survival was found for patients with DA and it-PVA after stratification for disease stage.Seven(23%)of 31 patients with synchronous stage IV disease underwent resection of the primary tumor,combined with local treatment of oligometastases.Local treatment of metastases was associated with an overall survival of 37 mo,compared to 14 and 6 mo for systemic therapy and supportive care,respectively.CONCLUSION Survival of patients with DA and it-PVA is comparable per disease stage.These results suggest a potential benefit for local treatment strategies in selected patients with oligometastases,although additional prospective studies are needed. 展开更多
关键词 Duodenal adenocarcinoma Papilla of Vater adenocarcinoma Clinical outcomes Local treatment METASTASES SURVIVAL
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Economic value and exploiting approaches of sea asparagus, a seawater-irrigated vegetable 被引量:1
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作者 Litian Feng Bin Ji Bin Su 《Agricultural Sciences》 2013年第9期40-44,共5页
Sea asparagus is a newly emerging seawater-irrigated vegetable. Firstly, the economic value of sea asparagus was introduced, and then, someexploiting approaches of sea asparagus werefully reviewed. The exploiting appr... Sea asparagus is a newly emerging seawater-irrigated vegetable. Firstly, the economic value of sea asparagus was introduced, and then, someexploiting approaches of sea asparagus werefully reviewed. The exploiting approaches mainly include fresh vegetable, pickle, bio-salt, health-care products, animal feed, vegetable oil, bio-diesel and skin-care products. 展开更多
关键词 Sea ASPARAGUS Seawater-Irrigated VEGETABLE ECONOMIC Value Exploiting APPROACHES Bio-Salt
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Adopting Health Apps, What’s Hindering Doctors and Patients? 被引量:1
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作者 Farhang Dehzad Cokky Hilhorst +1 位作者 Cas de Bie Eric Claassen 《Health》 2014年第16期2204-2217,共14页
There are high expectations for Mobile Health to transform health into a sustainable and prevention-based system. Unfortunately it has not reached its scale of adoption many had hoped for, due to the existence of adop... There are high expectations for Mobile Health to transform health into a sustainable and prevention-based system. Unfortunately it has not reached its scale of adoption many had hoped for, due to the existence of adoption barriers. More insight into these barriers fosters adoption of mHealth and the innovation it can bring to worldwide healthcare. This study investigates the main barriers in the adoption of mHealth, their underlying causes and their breakthrough possibilities. All the data are gathered from an international and multi-stakeholder point of view. First of all we tried to identify the main barriers by doing an international literature study. Second of all we asked Dutch mHealth Key Opinion Leaders (KOLs) to rank the barriers to importance. These KOLs were from different stakeholder groups;policy-makers, users and developers. At last we asked the KOLs in interviews for underlying causes and breakthrough opportunities of the barriers. Eventually twelve main adoption barriers emerged. According to literature and to the KOLs the most important barriers are “Integration and interoperability” and “Business case”. An underlying cause for the barrier “Integration and interoperability” might be the active closed power system of technology suppliers, which exists in the Netherlands. Furthermore there seems to be a difference in the importance of the barriers “Privacy and security” and “Conservative culture” when perceptions of Dutch KOLS and international literature are compared. Within the stakeholders-groups, the KOLs think differently about the importance of the barriers “Visionless development” and “Competing payment mechanism”. The Dutch healthcare insurers could take a more leading role in the fragmented landscape of mHealth in the Netherlands, by strategically funding new initiatives that use open standards and deliver better value for end-users. Other chances might lie in the international cooperation between countries to overcome certain barriers. 展开更多
关键词 MOBILE HEALTH ADOPTION Barriers HEALTH INNOVATION
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应用飞秒二维电子光谱中的Stark信号追踪电子转移动力学
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作者 马菲 Rienk van Grondelle 于龙江 《光谱学与光谱分析》 SCIE EI CAS CSCD 北大核心 2020年第S01期329-330,共2页
二维电子光谱(2DES)[1]是飞秒光化学领域最前沿的实验手段之一,它给出全面而直观的光谱动力学信息,可以非常有效地研究超快能量传递与电子转移的动力学过程[2],例如光合作用的原初步骤——将太阳光能转化为电化学能。光合反应中心(RC)色... 二维电子光谱(2DES)[1]是飞秒光化学领域最前沿的实验手段之一,它给出全面而直观的光谱动力学信息,可以非常有效地研究超快能量传递与电子转移的动力学过程[2],例如光合作用的原初步骤——将太阳光能转化为电化学能。光合反应中心(RC)色素-蛋白复合物是实现该光电转化的场所,其中多个色素分子形成电子传递链,转化量子效率接近100%。在应用2DES研究了其超高转化率背后的物理机制[3-4]的基础上,我们最近发现了各电荷分离(CT)中间态的存在会影响色素分子周边电场,导致其发生Stark位移。我们阐明了这些信号的物理来源,定量了Stark位移的数值,并分析了Stark信号的衰减动力学。在此基础上,提出了Stark效应对电子转移速率的影响。该工作也证明了2DES中出现的Stark信号可以用来有效地追踪电子转移的动力学过程,适合广泛应用。 展开更多
关键词 二维电子光谱(2DES) 电子转移 STARK位移 光合作用 反应中心复合物(RC)
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