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An improved GNSS ambiguity best integer equivariant estimation method with Laplacian distribution for urban low-cost RTK positioning

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Satellite Navigation 2024年第1期5卷 109-124页

作者： Ying Liu Wanke Liu xiaohong zhang Yantao Liang Xianlu Tao Liye Ma School of Geodesy and Geomatics Hubei Luojia LaboratoryWuhan University129 Luoyu RoadWuhan430079HubeiChina Chinese Antarctic Center of Surveying and Mapping Wuhan University129 Luoyu RoadWuhan430079HubeiChina School of Instrument Science and Engineering Southeast UniversityNanjingJiangsuChina The 54 Research Institute of China Electronics Technology Group CorporationShijiazhuang050081HebeiChina State Key Laboratory of Satellite Navigation System and Equipment Technology Shijiazhuang050081HebeiChina

The integer least squares(ILS)estimation is commonly used for carrier phase ambiguity resolution(AR).More recently,the best integer equivariant(BIE)estimation has also attracted an attention for complex application scenarios,which exhibits higher reliability by a weighted fusion of integer ***,traditional BIE estimation with Gaussian distribution(GBIE)faces challenges in fully utilizing the advantages of BIE for urban low-cost positioning,mainly due to the presence of outliers and unmodeled *** this end,an improved BIE estimation method with Laplacian distribution(LBIE)is proposed,and several key issues are discussed,including the weight function of LBIE,determination of the candidates included based on the OIA test,and derivation of the variance of LBIE solutions for reliability *** results show that the proposed LBIE method has the positioning accuracy similar to the BIE using multivariate t-distribution(TBIE),and significantly outperforms the ILS-PAR and GBIE *** an urban expressway test with a Huawei Mate40 smartphone,the LBIE method has positioning errors of less than 0.5 m in three directions and obtains over 50%improvements compared to the ILS-PAR and GBIE *** an urban canyon test with a low-cost receiver STA8100 produced by STMicroelectronics,the positioning accuracy of LBIE in three directions is 0.112 m,0.107 m,and 0.252 m,respectively,with improvements of 17.6%,27.2%,and 26.1%compared to GBIE,and 23.3%,28.2%,and 30.6%compared to ***,its computational time increases by 30–40%compared to ILS-PAR and is approximately half of that using TBIE.

关键词： Ambiguity resolution Best integer equivariant estimation Laplacian distribution Urban environments Low-cost GNSS receivers Real-time kinematic

Biochar regulates biogeochemical cycling of iron and chromium in a soil-rice system by stimulating Geobacter and Clostridium

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Pedosphere 2024年第5期34卷 929-940页

作者： Min XU Yang LIN Jing MA Lulu LONG Chao CHEN Gang YANG Chun SONG Jun WU xiaohong zhang Peng GAO College of Environmental Science Sichuan Agricultural University Soil Water and Ecosystem Sciences Department University of Florida College of Water Conservancy and Hydropower Engineering Sichuan Agricultural University Department of Environmental and Occupational Health University of Pittsburgh School of Public Health

In soil-rice systems,microbial reduction of iron （Fe） has been recognized as a crucial biogeochemical process that regulates Fe and chromium （Cr）translocation;however,the underlying processes are *** investigate the impacts of biochar on the biochemical cycling of Fe and Cr and their toxicity to rice,maize straw biochar was applied at 1%（weight/weight） to a paddy soil spiked with 300 mg kg-1Cr under two phosphorus （P） levels (0 or 90 mg kg-1) in a pot *** key microbial groups affecting Fe dissimilatory reduction and their environmental drivers were *** inhibited root Cr uptake by 36%,owing to the promoted iron plaque （IP） formation on the rice root *** analysis showed that Fe concentration in pore water was strongly linked to the abundances of Geobacter （r=0.81–0.94,P<0.05） and Clostridium （r=0.83–0.95,P<0.05）,indicating that Geobacter and Clostridium played essential roles in Fe *** analysis showed that labile carbon and pore water P concentrations were the key determinants influencing Fe-reducing bacterial abundances,accounting for 42%and 32%of the variation in community composition,***,biochar increased Fe and P concentrations in root cell walls,which retained more ***,Cr stress in rice under biochar treatment was relieved through increasing IP formation and altering subcellular *** mechanistic insights had important implications for reducing Cr uptake by rice.

关键词： chromium translocation iron plaque iron reduction maize straw biochar microbial reduction paddy soil phosphorus fertilization subcellular distribution

Broad-spectrum ginsentides are principal bioactives in unraveling the cure-all effects of ginseng

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Acta Pharmaceutica Sinica B 2024年第2期14卷 653-666页

作者： Shining Loo Antony Kam Bamaprasad Dutta xiaohong zhang Nan Feng Siu Kwan Sze Chuan-Fa Liu Xiaoliang Wang James P.Tam School of Biological Sciences Nanyang Technological UniversitySingapore 637551Singapore Academy of Pharmacy Xi’an Jiaotong-Liverpool UniversitySuzhou 215123China Department of Biological Sciences Xi’an Jiaotong-Liverpool UniversitySuzhou 215123China Institute of Materia Medica Chinese Academy of Medical SciencesBeijing 100050China Department of Health Sciences Brock UniversityNiagara RegionON L2S 3A1Canada

Stress and illness connection is complex and involves multiple physiological *** ginsengs,reputed for their broad-spectrum“cure-all”effect,are widely prescribed to treat stress and related ***,the identity of ginseng’s“cure-all”medicinal compounds that relieve stress remains ***,we identify ginsentides as the principal bioactives that coordinate multiple systems to restore homeostasis in response to *** are disulfide-rich,cell-penetrating and proteolytic-stable *** affinity-enrichment mass spectrometry target identification together with in vitro,ex vivo and in vivo validations,we show that highly purified or synthetic ginsentides promote vasorelaxation by producing nitric oxide through endothelial cells via intracellular PI3K/Akt signaling pathway,alleviate a1-adrenergic receptor overactivity by reversing phenylephrine-induced constriction of aorta,decrease monocyte adhesion to endothelial cells via CD166/ESAM/CD40 and inhibit P2Y12 receptors to reduce platelet *** administered ginsentides were effective in animal models to reduce ADP-induced platelet aggregation,to prevent collagen and adrenalineinduced pulmonary thrombosis as well as anti-stress behavior of tail suspension and forced swimming tests in ***,these results strongly suggest that ginsentides are the principal panacea compounds of ginsengs because of their ability to target multiple extra-and intra-cellular proteins to reverse stress-induced damages.

关键词： Ginseng Cysteine-rich peptides Microproteins Cure-all Stress Homeostasis

1843—2020年上海城市扩张时空过程及机理分析

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地理学报 2024年第5期79卷 1286-1302页

作者：李爽张晓虹复旦大学历史地理研究中心上海200433

上海作为中国近现代城市化最为显著的城市之一,自1843年开埠以来城市格局与空间范围变化巨大,重建并分析其扩张过程,对于深刻理解上海乃至中国城市化进程具有重要意义。本文通过收集1843—2020年上海城市旧地图、中华民国(1912—1949年... 详细信息

上海作为中国近现代城市化最为显著的城市之一,自1843年开埠以来城市格局与空间范围变化巨大,重建并分析其扩张过程,对于深刻理解上海乃至中国城市化进程具有重要意义。本文通过收集1843—2020年上海城市旧地图、中华民国(1912—1949年)地形图、解密卫星影像、遥感数据等多源多精度城市空间数据,分别提取城市建成区信息,重建了开埠以来建成区时间序列,研究了上海开埠以来的城市扩张时空过程及机理。结果表明:(1) 1843—2020年上海建成区面积增长了约1453倍,扩张速率、扩张强度发生了剧烈变化;(2)紧凑度随着时间推进不断下降,分形维数则随着时间变化呈现出了一定的周期;(3)建成区重心位置呈现出先向北后向南发展的趋势,其中最主要的扩张方向为西南及南偏西;(4)优越的自然位置奠定了上海被选为开埠城市发展的先决条件,社会变迁及政策驱动作为最根本的驱动力决定着城市在不同阶段发展的最主要方向,产业经济发展、人口迁移、交通发展等多因素也在复合影响着这一时空过程。本文廓清了上海自开埠以来的城市扩张过程及机理,为更深刻理解城市变迁、人地关系演变提供历史知识与科学支撑;同时,中华民国地形图、解密影像等覆盖范围广、制作精度高的历史资料,可作为百年尺度研究的历史基础数据,对更长时序研究具有重要的启发意义。

关键词：城市扩张上海历史地理长时间序列古旧地图

枸杞多糖的免疫调节作用及其在畜禽生产中的应用研究进展

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中国畜牧杂志 2024年第2期60卷 124-130页

作者：张小红天水农业学校甘肃天水741400

枸杞多糖(LBP)是枸杞叶、果中最重要的活性成分之一,因其无毒、可降解及良好的生物活性而被国内外广泛关注。LBP因具有免疫调节作用,作为免疫增效剂和良好的疫苗佐剂应用于畜禽养殖及疾病防治的实践和研究。本文综述了LBP结构与生物活... 详细信息

枸杞多糖(LBP)是枸杞叶、果中最重要的活性成分之一,因其无毒、可降解及良好的生物活性而被国内外广泛关注。LBP因具有免疫调节作用,作为免疫增效剂和良好的疫苗佐剂应用于畜禽养殖及疾病防治的实践和研究。本文综述了LBP结构与生物活性的关系、LBP的免疫调节作用及其在畜禽生产中的应用,以期为LBP在畜禽安全养殖、疾病防治中的研究及应用开发提供参考。

关键词：枸杞多糖生物活性免疫调节畜禽生产

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天然云冷杉林树木生长与树木大小、竞争和树种多样性的关系

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北京林业大学学报 2024年第5期46卷 64-72页

作者：张岚棋杨华张晓红北京林业大学林木资源高效生产全国重点实验室北京100083 国家林业和草原局国际合作交流中心北京100714

【目的】林分内林木大小、竞争和树种多样性等多方面因素影响着林木的生长,而胸高断面积生长量通常被用来描述树木生长状态。本文利用长白山云冷杉针阔混交林主要树种的单木胸高断面积生长量建立随机森林模型,研究和量化影响树木生长的... 详细信息

【目的】林分内林木大小、竞争和树种多样性等多方面因素影响着林木的生长,而胸高断面积生长量通常被用来描述树木生长状态。本文利用长白山云冷杉针阔混交林主要树种的单木胸高断面积生长量建立随机森林模型,研究和量化影响树木生长的环境因素,旨在为该地区的云冷杉针阔混交林生长预估提供理论依据。【方法】连续24年(1987—2010年)对总样木数为6903株的固定样地进行数据调查,应用随机森林算法,选取单木、竞争因子、多样性和气候方面共11个调查因子,对混交林中6个主要树种建立胸高断面积生长量模型,并使用10折交叉验证法来优化超参数mtry和评估模型结果。【结果】(1)臭冷杉、云杉、红松、椴树、枫桦、白桦6个主要树种胸高断面积生长量模型的决定系数分别为0.663、0.683、0.695、0.459、0.384和0.568。(2)单木胸高断面积是最重要的因子,对树木生长有着很强的正向影响;竞争因子和树木大小多样性是影响树木生长的主要因素,单木胸高断面积生长量随着竞争因子、树木大小多样性增加而下降。(3)树种多样性对树木生长的影响比较有限,树种多样性指数和混交度的增加会一定程度加快云杉、臭冷杉和红松的生长速度;而气候因子对树木生长的影响则相对较小。【结论】树木生长在很大程度上依赖于其自身的生长潜力,在外界环境中主要受到来自林木间竞争和树木大小多样性的抑制,而树种多样性的增加也能在一定程度促进林内优势树种的生长;随机森林模型能够很好地量化和显出各变量与单木胸高断面积生长量之间复杂的关系,可以作为森林管理评价工具,为森林生长收获预估提供新的方法。

关键词：树木生长树木大小竞争树种多样性随机森林模型

Externallyvalidated nomogramfor predicting short-term pregnancy outcome of singleton pregnancies with fetal growth restriction(FGR)

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Gynecology and Obstetrics Clinical Medicine 2024年第1期4卷 21-30页

作者： Fufen Yin Mingrui Jin Yujing Li Yang Li Xiuju Yin Junshu Xie xiaohong zhang Department of Obstetrics and Gynecology Peking University People's HospitalBeijingChina Department of Ophthalmology Beijing Tongren Eye CenterCapital Medical UniversityBeijingChina Department of Pathology China Medical University College of Basic Medical SciencesShenyangLiaoningChina Department of Obstetrics and Gynecology The Affiliated Hospital of Qingdao UniversityQingdaoShandongChina

Objective This studyaimed at developing an available predictive model of singleton pregnancies with fetal growth restriction(FGR)for accurate and individualised prognosis *** The prediction nomogram was developed by using multivariable Cox regression with data for 301 singleton FGR pregnancies at Peking University People's *** validation was performed in 321eligible singleton FGR pregnancies at the Affiliated Hospital of Qingdao *** Absent umbilical arterial flow,fetal anomaly,history of abnormal pregnancy,non-cephalic presentation and historyof caesarean sectionwere independent prognostic factors foradverse perinatal outcomes in singleton FGR pregnancies in the training *** the training cohort of the internal validation set,the nomogram estimated pregnancy prognosis of FGR singleton pregnancies based on these five variables,with a concordance index(C-index)of 0.859(95%Cl:0.81 to 0.90)for predicting termination of pregnancy(TOP),which included intrauterine fetal death and therapeutic lethal induction,with a C-index of 0.92(95%Cl:0.86 to 0.98)for predicting stillbirth,and a C-index of 0.87(95%Cl:0.83 to 0.92)for predicting therapeutic lethal induction with ***,consistent results wereobserved in the external validation set,witha C-index of 0.776(95%Cl:0.71 to 0.84)for predicting TOP,which included intrauterine fetal death and therapeutic lethal induction,with a C-index of 0.773(95%Cl:0.70 to 0.84)for predicting stillbirth,and a C-index of 0.776(95%Cl:0.70 to 0.85)for predicting therapeutic lethal induction with ***,the calibrations of the nomograms predicting the 28th and 34th TOPfreegestation week strongly corresponded to theactual *** This prediction model may help clinicians indecision-making for singleton pregnancies with FGR,especially for patients with a single abnormal umbilical arterial flow orfetal anomaly,without induced labour indications for thes

关键词： fetal pregnancy nomogram

不同水深层的GNSS信号特征分析及其导航场景聚类划分

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武汉大学学报（信息科学版） 2024年第1期49卷 139-145页

作者：陈惟杰朱锋郭斐张小红武汉大学测绘学院湖北武汉430079 湖北珞珈实验室湖北武汉430079

导航场景的划分对于自适应无缝导航定位服务具有重要意义。针对目前水上/水下导航场景划分简单、颗粒度不够的问题,通过采集位于不同水域内的全球导航卫星系统(global navigation satellite system,GNSS)观测数据,分析了不同水深层的GNS... 详细信息

导航场景的划分对于自适应无缝导航定位服务具有重要意义。针对目前水上/水下导航场景划分简单、颗粒度不够的问题,通过采集位于不同水域内的全球导航卫星系统(global navigation satellite system,GNSS)观测数据,分析了不同水深层的GNSS观测信号质量与特征,结果表明,水下导航场景具有显著的分层性。考虑到导航场景具有分割、合并、联通等固有属性,通过K均值聚类将水下导航场景细分为浸水(8.5 cm)3层。利用多种GNSS信号特征进行了导航场景分类实验,结果表明,聚类正确率达到90.4%,验证了浸水、浅水、深水导航场景划分的有效性。

关键词： GNSS 导航场景感知水上水下场景 K均值聚类

一种土地类型标签精细化的GNSS-R土壤湿度反演方法

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武汉大学学报（信息科学版） 2024年第1期49卷 47-55页

作者：郭斐董桂芳朱逸凡张小红武汉大学测绘学院湖北武汉430079

针对传统的星基全球导航卫星系统反射测量(global navigation satellite system–reflectometry,GNSS-R)技术在土壤湿度反演中对土地覆盖类型信息利用不全面的问题,引入基于国际地圈生物圈计划(international geosphere biosphere programme,IGBP)分类的土地覆盖类型数据,考虑不同土地类型间的相似性和差异性,根据语义关系设计了精细化的特征标签,并将其加入BP(back propagation)神经网络中构建土壤湿度反演模型。利用该方法得到的土壤湿度与参考值的相关系数为0.85,均方根误差为0.060 cm^(3)/cm^(3),相比于已有的IGBP编号标签法,反演精度提升了7.7%。结果表明,精细化土地覆盖类型标签法可以更大程度地利用土地覆盖信息,不依赖植被、地表粗糙度等辅助数据,有效实现土壤湿度反演。

关键词： GNSS反射测量技术土壤湿度 IGBP土地覆盖类型标签精细化 BP神经网络