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基于SPEI的洮河流域气象干旱时空特征分析
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作者 瞿德业 杨明月 +5 位作者 刘婷婷 杨山泉 谌越 夏搏 柴文博 丁春伟 《水利水电科技进展》 CSCD 北大核心 2024年第5期32-40,共9页
基于洮河流域1976—2020年逐月的气温和降水量资料,计算了季尺度和年尺度的标准化降水蒸散指数(SPEI),采用时间序列平稳性检验法和干旱频率法定量分析了季尺度和年尺度不同等级气象干旱频率的变化规律及空间分布特征,采用云模型分析了... 基于洮河流域1976—2020年逐月的气温和降水量资料,计算了季尺度和年尺度的标准化降水蒸散指数(SPEI),采用时间序列平稳性检验法和干旱频率法定量分析了季尺度和年尺度不同等级气象干旱频率的变化规律及空间分布特征,采用云模型分析了年尺度气象干旱时空分布的随机性与稳定性。结果表明:在季尺度上,四季的干旱频率都在30%左右,干旱主要发生在春冬两季;在年尺度上,流域以轻旱、中旱为主,轻旱、中旱发生频率高,重旱、特旱发生频率偏低,总体偏干旱;在空间分布上,干旱主要发生在流域的中下游区域;1976—2020年流域干旱化程度有所减弱,干旱化趋势稳定,干旱化程度波动较小。 展开更多
关键词 气象干旱 时空特征 spei 云模型 洮河流域
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1981─2020年河北省基于SPEI的干旱变化特征分析
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作者 魏丽欣 赵春雷 +2 位作者 张良玉 高万泉 王欢 《江西农业学报》 CAS 2024年第1期95-101,共7页
基于1981─2020年河北省138个气象站点的逐月降水和气温数据,计算了不同时间尺度的标准化降水蒸散指数(SPEI),并利用Sen趋势分析、Mann-Kendall检验及反距离权重插值等方法,分析了河北省近40年干旱的时空变化特征。结果表明:1981─2020... 基于1981─2020年河北省138个气象站点的逐月降水和气温数据,计算了不同时间尺度的标准化降水蒸散指数(SPEI),并利用Sen趋势分析、Mann-Kendall检验及反距离权重插值等方法,分析了河北省近40年干旱的时空变化特征。结果表明:1981─2020年河北省月、季、年尺度的SPEI值均呈下降趋势,且随着时间尺度的加大,发生干旱的频率下降,持续时间延长。春季、夏季和年际的SPEI值均呈下降趋势,秋季和冬季的SPEI值均呈上升趋势。2016─2020、2011─2020年春季和冬季均处于变湿状态,夏季和秋季均处于变干状态。2011─2020年河北省大部分地区呈干旱状态。不同年代季尺度和年尺度的干旱频率整体上呈增加趋势。河北省发生的轻、中度干旱事件多于重度以上干旱事件。20世纪90年代、21世纪10年代SPEI值减少区域的占比大。20世纪80年代、21世纪00年代SPEI值增加区域的占比大。 展开更多
关键词 河北省 spei指数 干旱 变化特征
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基于GRACE重力卫星与SPEI的云南干旱监测 被引量:1
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作者 游智文 李肖肖 +1 位作者 阳勇 鲁梦格 《节水灌溉》 北大核心 2024年第3期34-41,49,共9页
针对云南省干旱多发、旱灾严重的特点,选取1981年1月-2020年6月长时间序列的历史时期典型水文干旱年及干旱事件,探索GRACE卫星反演数据在监测云南地区干旱方面的适用性,旨在提出解决无资料或少资料地区干旱监测困难的新方法。研究基于GR... 针对云南省干旱多发、旱灾严重的特点,选取1981年1月-2020年6月长时间序列的历史时期典型水文干旱年及干旱事件,探索GRACE卫星反演数据在监测云南地区干旱方面的适用性,旨在提出解决无资料或少资料地区干旱监测困难的新方法。研究基于GRACE重力卫星数据反演得到云南省滇中、滇东北、滇东南、滇西南、滇西北5个分区月均储水量变化量,计算各分区的旱涝指标-相对储水量指数,利用相对储水量指数对云南省各分区干旱情况进行分析,并从月时间尺度上对比了相对储水量指数和标准降水蒸散指数SPEI3的干旱分析结论。研究结果表明:基于GRACE重力卫星数据反演构建的相对储水量指数在典型水文干旱年内的监测结果与实际干旱情况基本一致,其在滇中地区的适用性最佳,对于春季干旱的监测精度优于其他季节,反演数据能够一定程度上反映云南省不同地区、不同季节干旱程度;利用SPEI3对云南全省以及不同分区的旱情进行监测,结果与统计年鉴记载干旱事件较为吻合,其在滇东南地区的监测精度优于其他分区,在夏、冬两季精度优于春季;GRACE和SPEI3都较好地捕捉到了历史时期的典型干旱年及干旱事件,在选取的24场典型干旱事件中各分区的最高吻合率均达到了15/24;总体上两种指数在各分区漏报率均维持在较低水平,最高不超过1/3,其中SPEI3相较于GRACE更不易出现漏报的情况,其最低漏报率仅为1/8,两种指数在全省及各分区的旱情监测方面均表现出较好的适用性。 展开更多
关键词 云南省 GRACE卫星数据反演 干旱指数 相对储水量指数 spei 干旱监测 监测精度
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基于SPEI的陕西苹果产区近60a干旱变化特征
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作者 张勇 黄俊芳 +3 位作者 刘璐 张维敏 屈振江 梁轶 《中国农学通报》 2024年第23期105-117,共13页
研究旨在明确气候变暖背景下陕西苹果产区的干旱变化特征,为陕西苹果产区适应气候变化,科学指导陕西苹果防旱减损提供参考。利用陕西省苹果产区近60 a的气象站月降水、气温资料,计算陕西苹果各产区年、生长季、各生育期的标准化降水蒸... 研究旨在明确气候变暖背景下陕西苹果产区的干旱变化特征,为陕西苹果产区适应气候变化,科学指导陕西苹果防旱减损提供参考。利用陕西省苹果产区近60 a的气象站月降水、气温资料,计算陕西苹果各产区年、生长季、各生育期的标准化降水蒸散指数SPEI,对其进行趋势、突变和周期变化分析。研究结果表明近60 a陕西苹果产区年际明显趋于干旱,生长季总体趋于干旱,突变点多集中在1970s和1990s,1990s后干旱趋势较为明显,其中渭北东部产区干旱趋势尤为显著、干旱风险持续增加;萌芽—幼果期干旱趋势十分明显,干旱风险持续增加,突变点多集中在1970s后期至1980s初期和1990s初期,1990s初期后干旱趋势较为明显,产区中渭北西部、渭北东部、关中的干旱趋势显著;着色—成熟期、越冬休眠期总体趋于干旱,突变点多集中在1970s,1970s中后期以来呈干旱趋势,各产区均存在干旱趋势但变化趋势不显著;果实膨大期则以波动变化为主,未有显著的变化趋势。基于SPEI的干旱分析结合了降雨和蒸散发、考虑了更长时间尺度、适用于不同气候区域,更能客观反映气候变暖背景下陕西苹果产区干旱情况。气候变化造成的降水偏少、气温升高是陕西苹果产区趋于干旱的主要影响因素。 展开更多
关键词 陕西苹果 spei 分生育期 趋势 突变 周期
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基于SPEI的黑龙江省干旱时空分布特征分析
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作者 施巧 姜宁 +1 位作者 孟凡香 田肖冉 《水电能源科学》 北大核心 2024年第3期29-32,共4页
为分析黑龙江省干旱时空分布特征,利用黑龙江省27个站点1961~2020年的气象数据,采用Penman-Monteith公式计算不同时间尺度的标准化降水蒸散指数(SPEI),从时间尺度和空间尺度分析黑龙江省干旱的分布特征。结果表明,黑龙江省近60年来干旱... 为分析黑龙江省干旱时空分布特征,利用黑龙江省27个站点1961~2020年的气象数据,采用Penman-Monteith公式计算不同时间尺度的标准化降水蒸散指数(SPEI),从时间尺度和空间尺度分析黑龙江省干旱的分布特征。结果表明,黑龙江省近60年来干旱趋势在逐渐减弱,慢慢呈现湿润化趋势;春、夏、秋季呈不显著湿润化趋势(P>0.05),冬季呈显著湿润化趋势(P<0.05);在空间上其北部、西北部和东北部为干旱频发区,且干旱程度上多以轻旱和中旱为主。黑龙江省整体上干旱趋势减弱,干旱时空分布具有较明显的季节性和区域性。 展开更多
关键词 spei指数 干旱 时空分布特征 黑龙江省
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基于SPEI的北疆1961—2020年气象干旱变化特征
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作者 卫炎豪 古丽娜孜 +3 位作者 巴特尔·巴克 帕丽扎提·玉素甫 祖力克艳·麻那甫 帕提古力·麦麦提 《湖北农业科学》 2024年第5期37-44,214,共9页
基于北疆26个主要气象站点1961—2020年逐日气象数据,选取标准化降水蒸散指数(SPEI)为气象干旱指标,采用Mann-Kendall突变检验、小波分析等方法对北疆年及春、夏两季SPEI和不同等级气象干旱影响范围变化特征进行了探究。结果表明,北疆... 基于北疆26个主要气象站点1961—2020年逐日气象数据,选取标准化降水蒸散指数(SPEI)为气象干旱指标,采用Mann-Kendall突变检验、小波分析等方法对北疆年及春、夏两季SPEI和不同等级气象干旱影响范围变化特征进行了探究。结果表明,北疆实际轻旱情况更适合以-1.0<SPEI≤0识别;与年尺度的湿润化趋势相反,北疆春、夏两季均呈不同程度的干旱化趋势,且夏季极端气象干旱(重旱、特旱)事件影响范围有显著扩大趋势;1961—2020年不同尺度SPEI有1~4年的主变化周期;北疆整体气候于20世纪80年代转变后在1993—2010年呈显著湿润化趋势,春、夏季气候分别于2014年及1997年出现了由湿转干的趋势信号;研究区夏季的干旱情况于1988年开始逐渐缓解,但在2008年再次突变后干旱情况又开始逐步加剧。 展开更多
关键词 标准化降水蒸散指数(spei) 气象干旱 小波分析 Mann-Kendall突变检验 北疆
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基于SPEI指数的辽宁省玉米干旱特征分析
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作者 王艺霖 王蕊 +3 位作者 单凤君 张筱渲 赵诣 孙颖 《辽宁工业大学学报(自然科学版)》 2024年第4期273-280,共8页
基于1961—2020年辽宁省24个国家级气象台站逐日观测数据,根据SPEI的计算、Mann-Kendall法、小波分析法,采用灰色关联度分析方法,对辽宁省玉米不同生长阶段标准降水蒸散指数(SPEI)进行了定量评价,并进行比较全面的分析。结果表明,从玉... 基于1961—2020年辽宁省24个国家级气象台站逐日观测数据,根据SPEI的计算、Mann-Kendall法、小波分析法,采用灰色关联度分析方法,对辽宁省玉米不同生长阶段标准降水蒸散指数(SPEI)进行了定量评价,并进行比较全面的分析。结果表明,从玉米全生育期来看,近60 a降水量总体变化趋势并不显著,与SPEI呈显著正相关;辽宁省玉米生长期平均气温与SPEI呈负相关;玉米全生育期SPEI在时间上均呈上升趋势;从整体来看,在干旱站次比方面辽宁省的玉米生产并没有全域性干旱现象。 展开更多
关键词 spei 干旱站次比 辽宁省 玉米 气象干旱
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Standardized Baseflow Drought Index Comparison to SPEI in High Baseflow Streams
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作者 Katherine A. Clancy 《Journal of Water Resource and Protection》 2023年第11期557-580,共24页
Increased use of streamflow, most importantly minimum flow/baseflow data should be incorporated into drought indices, especially in regions where streams have a high baseflow component. Standard departure for streamfl... Increased use of streamflow, most importantly minimum flow/baseflow data should be incorporated into drought indices, especially in regions where streams have a high baseflow component. Standard departure for streamflow (SDSF) and standard departure for baseflow (SDBF) were compared to the standardized precipitation and evapotranspiration index (SPEI) drought index values for 17 baseflow-dominated watersheds in the northern, central, and southern regions of Wisconsin. For each watershed, comparisons of SDSF, SDBF, and SPEI time series (for 1, 3, and 12-month time scales) were evaluated using correlation, run lengths of negative and positive values, sign congruence, and Mann-Kendall trend test. In general, SDBF performed better than SDSF for longer time scales. Trends of wetness appear to be distinguished earlier in SDBF compared to SDSF and SPEI-1, SPEI-3, and SPEI-12. The results of this study are consistent with regional statewide climate studies on precipitation and changes in precipitation intensity. This study highlights how standardized baseflow data are robust and compare to SPEI 12-month time scales. 展开更多
关键词 spei BASEFLOW Drought Indices Streamflow
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基于SPEI-RRV和MC的云贵高原干旱状态识别
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作者 郝海宁 王新鹏 +1 位作者 简灵活 赵庆志 《人民长江》 北大核心 2024年第7期65-72,共8页
全球变暖趋势明显,致使区域性干湿变化特征的不确定性加剧。通过计算标准化降水蒸散指数(SPEI),结合可靠性-回弹性-脆弱性指标(reliability-resilience-vulnerability,RRV)和马尔科夫链估计(Markov Chains,MC)统计2000~2022年云贵高原... 全球变暖趋势明显,致使区域性干湿变化特征的不确定性加剧。通过计算标准化降水蒸散指数(SPEI),结合可靠性-回弹性-脆弱性指标(reliability-resilience-vulnerability,RRV)和马尔科夫链估计(Markov Chains,MC)统计2000~2022年云贵高原区域的干旱风险等级、干旱发生频率、涉及面积占比和平均持续时间,并采用Mann-Kendall检验法检验其趋势显著性,识别云贵高原的干旱事件,定量刻画干旱状态空间特征。结果表明:SPEI-RRV能够有效识别云贵高原干旱事件,该指数能较为精确地评价区域干旱状态;云贵高原78%的地区干旱状态有微弱的逐年加重趋势,有超过35%的概率会遭受从轻度到特级不同程度的干旱,东部丘陵区特旱的稳态概率为25%,该区域发生极端干旱概率较高。研究成果可为云贵高原干旱监测和干旱风险评估提供参考。 展开更多
关键词 干旱状态识别 spei-RRV 马尔科夫链 云贵高原
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Association between triglyceride-glucose index and colorectal polyps:A retrospective cross-sectional study 被引量:1
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作者 Ya-Jie Teng Ying-Xue Yang +5 位作者 Jing-Jing Yang Qiu-Yan Lu Jia-Yi Shi Jian-Hao Xu Jie Bao Qing-Hua Wang 《World Journal of Gastrointestinal Endoscopy》 2024年第2期55-63,共9页
BACKGROUND Colorectal polyps(CPs)are frequently occurring abnormal growths in the colorectum,and are a primary precursor of colorectal cancer(CRC).The triglyceride-glucose(TyG)index is a novel marker that assesses met... BACKGROUND Colorectal polyps(CPs)are frequently occurring abnormal growths in the colorectum,and are a primary precursor of colorectal cancer(CRC).The triglyceride-glucose(TyG)index is a novel marker that assesses metabolic health and insulin resistance,and has been linked to gastrointestinal cancers.AIM To investigate the potential association between the TyG index and CPs,as the relation between them has not been documented.METHODS A total of 2537 persons undergoing a routine health physical examination and colonoscopy at The First People's Hospital of Kunshan,Jiangsu Province,China,between January 2020 and December 2022 were included in this retrospective cross-sectional study.After excluding individuals who did not meet the eligibility criteria,descriptive statistics were used to compare characteristics between patients with and without CPs.Logistic regression analyses were conducted to determine the associations between the TyG index and the prevalence of CPs.The TyG index was calculated using the following formula:Ln[triglyceride(mg/dL)×glucose(mg/dL)/2].The presence and types of CPs was determined based on data from colonoscopy reports and pathology reports.RESULTS A nonlinear relation between the TyG index and the prevalence of CPs was identified,and exhibited a curvilinear pattern with a cut-off point of 2.31.A significant association was observed before the turning point,with an odds ratio(95% confidence interval)of 1.70(1.40,2.06),P<0.0001.However,the association between the TyG index and CPs was not significant after the cut-off point,with an odds ratio(95% confidence interval)of 0.57(0.27,1.23),P=0.1521.CONCLUSION Our study revealed a curvilinear association between the TyG index and CPs in Chinese individuals,suggesting its potential utility in developing colonoscopy screening strategies for preventing CRC. 展开更多
关键词 Triglyceride-glucose index Colorectal polyps Colorectal cancer Insulin resistance Cross-sectional study
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基于SPEI的濮阳夏玉米生长季干旱特征分析
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作者 董建设 《中国农学通报》 2024年第14期82-89,共8页
干旱是濮阳地区夏玉米生产过程中最主要的农业气象灾害,本研究旨在探究濮阳地区夏玉米生长季(6—9月)干旱的演变规律,并分析其对农业生产的影响,以便采取有效的防灾减灾措施。通过利用濮阳5个气象站点在1991—2020年间的逐月气温和降水... 干旱是濮阳地区夏玉米生产过程中最主要的农业气象灾害,本研究旨在探究濮阳地区夏玉米生长季(6—9月)干旱的演变规律,并分析其对农业生产的影响,以便采取有效的防灾减灾措施。通过利用濮阳5个气象站点在1991—2020年间的逐月气温和降水量数据,研究采用标准化降水蒸散指数(SPEI)结合小波分析和Mann-Kendall检验方法来识别干旱变化特征。研究发现,夏玉米苗期、穗期和花粒期干旱发生率分别为26.7%、30.3%和35%。特别是在2010年后,夏玉米各生长阶段均呈现干旱化趋势,并在1992、1995、1998、2002、2005、2018等年份观测到气候突变现象。周期性分析显示,不同生长阶段的干湿周期存在差异,其中苗期为8~9 a和20~25 a,穗期为6~10 a和15~25 a,花粒期为5 a、10 a和18~24 a,而整个生长季则为8~9 a和22 a。由于气候异常,自2010年以来,干湿周期性变化有所减弱,干旱化趋势明显,且存在干湿突变的风险。因此,针对濮阳地区夏玉米生产,建议加强气候监测、预警预报以及防灾减灾工作,以应对气候变化带来的挑战。 展开更多
关键词 濮阳 夏玉米 spei 干旱
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A phenology-based vegetation index for improving ratoon rice mapping using harmonized Landsat and Sentinel-2 data 被引量:1
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作者 Yunping Chen Jie Hu +6 位作者 Zhiwen Cai Jingya Yang Wei Zhou Qiong Hu Cong Wang Liangzhi You Baodong Xu 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第4期1164-1178,共15页
Ratoon rice,which refers to a second harvest of rice obtained from the regenerated tillers originating from the stubble of the first harvested crop,plays an important role in both food security and agroecology while r... Ratoon rice,which refers to a second harvest of rice obtained from the regenerated tillers originating from the stubble of the first harvested crop,plays an important role in both food security and agroecology while requiring minimal agricultural inputs.However,accurately identifying ratoon rice crops is challenging due to the similarity of its spectral features with other rice cropping systems(e.g.,double rice).Moreover,images with a high spatiotemporal resolution are essential since ratoon rice is generally cultivated in fragmented croplands within regions that frequently exhibit cloudy and rainy weather.In this study,taking Qichun County in Hubei Province,China as an example,we developed a new phenology-based ratoon rice vegetation index(PRVI)for the purpose of ratoon rice mapping at a 30 m spatial resolution using a robust time series generated from Harmonized Landsat and Sentinel-2(HLS)images.The PRVI that incorporated the red,near-infrared,and shortwave infrared 1 bands was developed based on the analysis of spectro-phenological separability and feature selection.Based on actual field samples,the performance of the PRVI for ratoon rice mapping was carefully evaluated by comparing it to several vegetation indices,including normalized difference vegetation index(NDVI),enhanced vegetation index(EVI)and land surface water index(LSWI).The results suggested that the PRVI could sufficiently capture the specific characteristics of ratoon rice,leading to a favorable separability between ratoon rice and other land cover types.Furthermore,the PRVI showed the best performance for identifying ratoon rice in the phenological phases characterized by grain filling and harvesting to tillering of the ratoon crop(GHS-TS2),indicating that only several images are required to obtain an accurate ratoon rice map.Finally,the PRVI performed better than NDVI,EVI,LSWI and their combination at the GHS-TS2 stages,with producer's accuracy and user's accuracy of 92.22 and 89.30%,respectively.These results demonstrate that the proposed PRVI based on HLS data can effectively identify ratoon rice in fragmented croplands at crucial phenological stages,which is promising for identifying the earliest timing of ratoon rice planting and can provide a fundamental dataset for crop management activities. 展开更多
关键词 ratoon rice phenology-based ratoon rice vegetation index(PRVI) phenological phase feature selection Harmonized Landsat Sentinel-2 data
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福建省植被NDVI演变特征及其对不同时间尺度SPEI的响应
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作者 李新妹 关辉 +2 位作者 翁升恒 吴作航 王宏 《海峡科学》 2024年第4期16-20,42,共6页
基于2001—2021年福建省植被NDVI及SPEI,通过趋势分析及相关分析法探究福建省植被生长状况时间变化特征及对干旱的响应。结果表明,福建省植被年平均NDVI值呈现出波动上升的发展趋势,年内NDVI月均值波峰集中在7—9月,且夏季>秋季>... 基于2001—2021年福建省植被NDVI及SPEI,通过趋势分析及相关分析法探究福建省植被生长状况时间变化特征及对干旱的响应。结果表明,福建省植被年平均NDVI值呈现出波动上升的发展趋势,年内NDVI月均值波峰集中在7—9月,且夏季>秋季>春季>冬季;不同时间尺度的SPEI反映出福建省的干湿情况,2001—2021年,福建省呈微弱的湿润化趋势;季节尺度上,春季、冬季NDVI与SPEI-01的相关系数分别为-0.560和-0.651(P<0.01),均呈显著负相关,而夏季、秋季NDVI与多时间尺度SPEI的相关系数很小,且不显著;月尺度上,两者的相关性较为复杂,仅当月NDVI与SPEI-01的相关系数-0.181(P<0.01)通过了显著性检验,呈较弱负相关,而滞后1~3个月的相关性均不显著,表明干旱对植被NDVI的影响一般出现在干旱发生的当月。 展开更多
关键词 NDVI spei 相关性 福建省
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On traceable iterated line graph and hamiltonian path index
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作者 NIU Zhao-hong XIONG Li-ming YANG Wei-hua 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2024年第2期239-252,共14页
Xiong and Liu[21]gave a characterization of the graphs G for which the n-iterated line graph L^(n)(G)is hamiltonian,for n≥2.In this paper,we study the existence of a hamiltonian path in L^(n)(G),and give a characteri... Xiong and Liu[21]gave a characterization of the graphs G for which the n-iterated line graph L^(n)(G)is hamiltonian,for n≥2.In this paper,we study the existence of a hamiltonian path in L^(n)(G),and give a characterization of G for which L^(n)(G)has a hamiltonian path.As applications,we use this characterization to give several upper bounds on the hamiltonian path index of a graph. 展开更多
关键词 iterated line graph TRACEABLE hamiltonian index hamiltonian path index
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An evaluation of ureteral diameter ratio and vesicoureteral reflux index in the treatment of primary vesicoureteral reflux
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作者 Yusuf Atakan Baltrak Nebil Akdogan +3 位作者 Mutlu Deger Volkan Izol Ibrahim Atilla Aridogan Nihat Satar 《Asian Journal of Urology》 CSCD 2024年第3期437-442,共6页
Objective:Vesicoureteral reflux(VUR)index is a simple,validated tool that reliably predicts significant improvement and spontaneous resolution of primary reflux in children.The aim of this study was to evaluate and co... Objective:Vesicoureteral reflux(VUR)index is a simple,validated tool that reliably predicts significant improvement and spontaneous resolution of primary reflux in children.The aim of this study was to evaluate and compare the ureter diameter ratio(UDR)and VUR index(VURx)of patients treated with endoscopic injection(EI)and ureteroneocystostomy(UNC)methods in the pediatric age group due to primary VUR.Methods:Patients under the age of 18 years old who underwent EI and UNC with the diagnosis of primary VUR between January 2011 and September 2021 were determined as the participants.The UDR was assessed using voiding cystourethrography,and the VURx score was determined prior to treatment based on hospital records included in the study.Results:A total of 255 patients,60(23.5%)boys and 195(76.5%)girls,with a mean age of 76.5(range 13.0e204.0)months,were included in the study.EI was applied to 130(51.0%)patients and UNC was applied to 125(49.0%)patients due to primary VUR.The optimum cut-off for the distal UDR was obtained as 0.17 with sensitivity and specificity of 73.0%and 63.0%,respectively.The positive and negative predictive values were 66.0%and 70.0%,respectively.Conclusion:When the UDR and VURx score are evaluated together for the surgical treatment of primary VUR in the pediatric age group,it is thought that it may be useful in predicting the clinical course of the disease and evaluating surgical treatment options. 展开更多
关键词 Distalureter diameter ratio Vesicoureteral reflux Vesicoureteral reflux index management Vesicoureteral reflux index
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Association between the cumulative triglyceride-glucose index and the recurrence of atrial fibrillation after radiofrequency catheter ablation
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作者 Qing YAN Jia-Qi LIANG +5 位作者 Yi-De YUAN Yuan LI Jia-Li FAN Wen-Huan WU Pan XU Jia-Hong XUE 《Journal of Geriatric Cardiology》 SCIE CAS CSCD 2024年第2期200-210,共11页
BACKGROUND Triglyceride-glucose(TyG)index values are a new surrogate marker for insulin resistance.This study aimed to explore the relationship between cumulative TyG index values and atrial fibrillation(AF)recurrence... BACKGROUND Triglyceride-glucose(TyG)index values are a new surrogate marker for insulin resistance.This study aimed to explore the relationship between cumulative TyG index values and atrial fibrillation(AF)recurrence after radiofrequency catheter ablation(RFCA).METHODS A total of 576 patients with AF who underwent RFCA at the Second Affiliated Hospital of Xi'an Jiaotong University were included in this study.The participants were grouped based on cumulative TyG index values tertiles within 3 months after ablation.Cox regression and restricted cubic spline analyses were used to determine the relationship between cumulative TyG index values and AF recurrence.The predictive value of all risk factors was assessed by receiver operating curve analysis.RESULTS There were 375 patients completed the study(age:63.23±10.73 years,64.27%male).The risk of AF recurrence increased with increasing cumulative TyG index values tertiles.After adjusting for potential confounders,patients in the medium cumulative TyG index group[hazard ratio(HR)=4.949,95%CI:1.778–13.778,P=0.002]and the high cumulative TyG index group(HR=8.716,95%CI:3.371–22.536,P<0.001)had a higher risk of AF recurrence than those in the low cumulative TyG index group.The restricted cubic spline regression model also showed an increased risk of AF recurrence with increasing cumulative TyG index values.When considering cumulative TyG index values,left atrial diameter,and lactate dehydrogenase levels as a comprehensive factor,the model could effectively predict AF recurrence after RFCA[area under the curve(AUC)=0.847,95%CI:0.797–0.897,P<0.001].CONCLUSIONS Cumulative TyG index values were a risk factor for AF recurrence after RFCA.Monitoring longitudinal TyG index values may assist with optimized for risk stratification and outcome prediction for AF recurrence. 展开更多
关键词 ATRIAL FIBRILLATION index
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Early peripheral perfusion index predicts 28-day outcome in patients with septic shock
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作者 Cheng Chi Hao Gong +2 位作者 Kai Yang Peng Peng Xiaoxia Zhang 《World Journal of Emergency Medicine》 SCIE CAS CSCD 2024年第5期372-378,共7页
BACKGROUND:To investigate the prognostic value of the peripheral perfusion index(PPI)in patients with septic shock.METHODS:This prospective cohort study,conducted at the emergency intensive care unit of Peking Univers... BACKGROUND:To investigate the prognostic value of the peripheral perfusion index(PPI)in patients with septic shock.METHODS:This prospective cohort study,conducted at the emergency intensive care unit of Peking University People's Hospital,recruited 200 patients with septic shock between January 2023 and August 2023.These patients were divided into survival(n=84)and death(n=116)groups based on 28-day outcomes.Clinical evaluations included laboratory tests and clinical scores,with lactate and PPI values assessed upon admission to the emergency room and at 6 h and 12 h after admission.Risk factors associated with mortality were analyzed using univariate and multivariate Cox regression analyses.Receiver operator characteristic(ROC)curve was used to assess predictive performance.Mortality rates were compared,and Kaplan-Meier survival plots were created.RESULTS:Compared to the survival group,patients in the death group were older and had more severe liver damage and coagulation dysfunction,necessitating higher norepinephrine doses and increased fl uid replacement.Higher lactate levels and lower PPI levels at 0 h,6 h,and 12 h were observed in the death group.Multivariate Cox regression identifi ed prolonged prothrombin time(PT),decreased 6-h PPI and 12-h PPI as independent risk factors for death.The area under the curves for 6-h PPI and 12-h PPI were 0.802(95%CI 0.742-0.863,P<0.001)and 0.945(95%CI 0.915-0.974,P<0.001),respectively,which were superior to Glasgow Coma Scale(GCS),Sequential Organ Failure Assessment(SOFA)scores(0.864 and 0.928).Cumulative mortality in the low PPI groups at 6 h and 12 h was signifi cantly higher than in the high PPI groups(6-h PPI:77.52%vs.22.54%;12-h PPI:92.04%vs.13.79%,P<0.001).CONCLUSION:PPI may have value in predicting 28-day mortality in patients with septic shock. 展开更多
关键词 Peripheral perfusion index Septic shock PROGNOSIS Predictive value
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Actuality and underlying mechanisms of systemic immuneinflammation index and geriatric nutritional risk index prognostic value in hepatocellular carcinoma
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作者 Konstantin Y Tchilikidi 《World Journal of Gastrointestinal Surgery》 SCIE 2024年第2期260-265,共6页
This editorial contains comments on the article“Correlation between preoperative systemic immune inflammation index,nutritional risk index,and prognosis of radical resection of liver cancer”in a recent issue of the ... This editorial contains comments on the article“Correlation between preoperative systemic immune inflammation index,nutritional risk index,and prognosis of radical resection of liver cancer”in a recent issue of the World Journal of Gastrointestinal Surgery.It pointed out the actuality and importance of the article and focused primarily on the underlying mechanisms making the systemic immuneinflammation index(SII)and geriatric nutritional risk index(GNRI)prediction features valuable.There are few publications on both SII and GNRI together in hepatocellular carcinoma(HCC)and patient prognosis after radical surgery.Neutrophils release cytokines,chemokines,and enzymes,degrade extracellular matrix,reduce cell adhesion,and create conditions for tumor cell invasion.Neutrophils promote the adhesion of tumor cells to endothelial cells,through physical anchoring.That results in the migration of tumor cells.Pro-angiogenic factors from platelets enhance tumor angiogenesis to meet tumor cell supply needs.Platelets can form a protective film on the surface of tumor cells.This allows avoiding blood flow damage as well as immune system attack.It also induces the epithelial-mesenchymal transformation of tumor cells that is critical for invasiveness.High SII is also associated with macro-and microvascular invasion and increased numbers of circulating tumor cells.A high GNRI was associated with significantly better progression-free and overall survival.HCC patients are a very special population that requires increased attention.SII and GNRI have significant survival prediction value in both palliative treatment and radical surgery settings.The underlying mechanisms of their possible predictive properties lie in the field of essential cancer features.Those features provide tumor nutrition,growth,and distribution throughout the body,such as vascular invasion.On the other hand,they are tied to the possibility of patients to resist tumor progression and development of complications in both postoperative and cancer-related settings.The article is of considerable interest.It would be helpful to continue the study follow-up to 2 years and longer.External validation of the data is needed. 展开更多
关键词 Systemic immune-inflammation index Geriatric nutritional risk index Radical surgery Transarterial chemoembolization Hepatocellular carcinoma Prognosis
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A Transparent Photoresist Made of Titanium Dioxide Nanoparticle-Embedded Acrylic Resin with a Tunable Refractive Index for UV-Imprint Lithography
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作者 Yinglu Liu Dan Wang +7 位作者 Changlin Liu Qianqian Hao Jian Li Jie-Xin Wang Xiuyun Chen Peng Zhong Xibin Shao Jian-Feng Chen 《Engineering》 SCIE EI CAS CSCD 2024年第6期96-104,共9页
Transparent photoresists with a high refractive index(RI)and high transmittance in visible wavelengths have promising functionalities in optical fields.This work reports a kind of tunable optical material composed of ... Transparent photoresists with a high refractive index(RI)and high transmittance in visible wavelengths have promising functionalities in optical fields.This work reports a kind of tunable optical material composed of titanium dioxide nanoparticles embedded in acrylic resin with a high RI for ultraviolet(UV)-imprint lithography.The hybrid film exhibits a tunable RI of up to 1.67(589 nm)after being cured by UV light,while maintaining both a high transparency of over 98%in the visible light range and a low haze of less than 0.05%.The precision machining of optical microstructures can be imprinted easily and efficiently using the hybrid resin,which acts as a light guide plate(LGP)to guide the light from the side to the top in order to conserve the energy of the display device.These preliminary studies based on both laboratory and commercial experiments pave the way for exploiting the unparalleled optical properties of nanocomposite resins and promoting their industrial application. 展开更多
关键词 PHOTORESIST Tunable refractive index Hanson solubility Ultraviolet imprint Organic-inorganic composites
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Antecedent Precipitation Index to Estimate Soil Moisture and Correlate as a Triggering Process in the Occurrence of Landslides
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作者 Marcio Augusto Ernesto De Moraes Walter Manoel Mendes Filho +6 位作者 Rodolfo Moreda Mendes Cassiano Antonio Bortolozo Daniel Metodiev Marcio Roberto Magalhães De Andrade Harideva Marturano Egas Tatiana Sussel Gonçalves Mendes Luana Albertani Pampuch 《International Journal of Geosciences》 CAS 2024年第1期70-86,共17页
Landslides are highly dangerous phenomena that occur in different parts of the world and pose significant threats to human populations. Intense rainfall events are the main triggering process for landslides in urbaniz... Landslides are highly dangerous phenomena that occur in different parts of the world and pose significant threats to human populations. Intense rainfall events are the main triggering process for landslides in urbanized slope regions, especially those considered high-risk areas. Various other factors contribute to the process;thus, it is essential to analyze the causes of such incidents in all possible ways. Soil moisture plays a critical role in the Earth’s surface-atmosphere interaction systems;hence, measurements and their estimations are crucial for understanding all processes involved in the water balance, especially those related to landslides. Soil moisture can be estimated from in-situ measurements using different sensors and techniques, satellite remote sensing, hydrological modeling, and indicators to index moisture conditions. Antecedent soil moisture can significantly impact runoff for the same rainfall event in a watershed. The Antecedent Precipitation Index (API) or “retained rainfall,” along with the antecedent moisture condition from the Natural Resources Conservation Service, is generally applied to estimate runoff in watersheds where data is limited or unavailable. This work aims to explore API in estimating soil moisture and establish thresholds based on landslide occurrences. The estimated soil moisture will be compared and calibrated using measurements obtained through multisensor capacitance probes installed in a high-risk area located in the mountainous region of Campos do Jordão municipality, São Paulo, Brazil. The API used in the calculation has been modified, where the recession coefficient depends on air temperature variability as well as the climatological mean temperature, which can be considered as losses in the water balance due to evapotranspiration. Once the API is calibrated, it will be used to extrapolate to the entire watershed and consequently estimate soil moisture. By utilizing recorded mass movements and comparing them with API and soil moisture, it will be possible to determine thresholds, thus enabling anticipation of landslide occurrences. 展开更多
关键词 LANDSLIDES Antecedent Precipitation index Soil Moisture Threshold Water Balance
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