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Characterization of multi-scale ionospheric irregularities using ground-based and space-based GNSS observations

Satellite Navigation 2021年第1期2卷 192-212页

作者： YuXiang Peng Wayne A Scales michael D Hartinger Zhonghua Xu shane Coyle Center for Space Science and Engineering Research Virginia TechBlacksburgVA 24061USA Bradley Department of Electrical and Computer Engineering Virginia TechBlacksburgVA 24061USA Space Science Institute BoulderCO 80301USA National Institute of Aerospace HamptonVA 23666USA Center for Space Science and Engineering Research Virginia TechBlacksburgVA 24061USA.

Ionospheric irregularities can adversely affect the performance of Global Navigation Satellite System (GNSS). How-ever, this opens the possibility of using GNSS as an effective ionospheric remote sensing tool. Despite ionospheric monitoring has been undertaken for decades, these irregularities in multiple spatial and temporal scales are still not fully understood. This paper reviews Virginia Tech’s recent studies on multi-scale ionospheric irregularities using ground-based and space-based GNSS observations. First, the relevant background of ionospheric irregularities and their impact on GNSS signals is reviewed. Next, three topics of ground-based observations of ionospheric irregulari-ties for which GNSS and other ground-based techniques are used simultaneously are reviewed. Both passive and active measurements in high-latitude regions are covered. modelling and observations in mid-latitude regions are considered as well. Emphasis is placed on the increased capability of assessing the multi-scale nature of ionospheric irregularities using other traditional techniques (e.g., radar, magnetometer, high frequency receivers) as well as GNSS observations (e.g., Total-Electron-Content or TEC, scintillation). Besides ground-based observations, recent advances in GNSS space-based ionospheric measurements are briefly reviewed. Finally, a new space-based ionospheric observa-tion technique using GNSS-based spacecraft formation flying and a differential TEC method is demonstrated using the newly developed Virginia Tech Formation Flying Testbed (VTFFTB). Based on multi-constellation multi-band GNSS, the VTFFTB has been developed into a hardware-in-the-loop simulation testbed with external high-fidelity global ionospheric model(s) for 3-satellite formation flying, which can potentially be used for new multi-scale ionospheric measurement mission design.

关键词： GNSS Ionospheric irregularities Remote sensing Active experiment Spacecraft formation flying

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一种改进RetinaNet深度学习网络的城乡结合部违章建筑检测方法

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重庆科技大学学报（自然科学版） 2024年第4期26卷 75-82页

作者：李作进曹亚男贺学乐李明虹李东阳 simon X.Yang 重庆科技大学电子与电气工程学院重庆401331 圭尔夫大学工程学院安大略圭尔夫N1G2W1

针对城乡结合部违章建筑类型多样化、小目标待检物较多且检测精度较低等问题,提出了一种改进RetinaNet深度学习网络的城乡结合部违章建筑检测方法。首先,在主干特征提取网络ResNet50中嵌入CA注意力机制,以增强网络对小目标的感知能力;其... 详细信息

针对城乡结合部违章建筑类型多样化、小目标待检物较多且检测精度较低等问题,提出了一种改进RetinaNet深度学习网络的城乡结合部违章建筑检测方法。首先,在主干特征提取网络ResNet50中嵌入CA注意力机制,以增强网络对小目标的感知能力;其次,在ResNet50中引入并行空洞卷积(DCB)模块,以实现多尺度特征融合,降低算法的漏检率;最后,将ResNet50网络的ReLU激活函数替换为GeLU激活函数,以加快模型收敛,提升模型稳定性。实验结果表明,改进后模型的平均准确率达到93.28%,参数量为3.920×107,可为城乡结合部违章建筑实时监测及拆除工作提供部分理论依据。

关键词：深度学习 RetinaNet 注意力机制违章建筑

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Aging effects on QT interval： Implications for cardiac safety of antipsychotic drugs

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Journal of Geriatric Cardiology 2014年第1期11卷 20-25页

作者： simon W. Rabkin Department of medicine (Cardiology) University of British Columbia 9th Floor 2775 Laurel St. Vancouver B.C. V5Z 1M9 Canada

Objectives To explore the effect of aging on cardiac toxicity specifically the interaction of age and antipsychotic drugs to alter the QT interval. methods The medline databases were searched using the OvidSP platforms with the search strategy：＂QT interval＂ or ＂QT＂ and ＂age＂ or ＂aging＂. The entry criteria were： over 10,000 apparently healthy individuals with data on both sexes; QT interval corrected for heart rate （QTc） and an expression of its variance for multiple age decades extending into the older ages. Results QTc increased in duration with increasing age. Considering a modest one SD increment in QTc in the normal population, the addition of Chlorpromazine produced a QTc on average greater than 450 ms for ages 70 years and older. Risperidone, that did not on average alter QTc, would be expected to produce a QTc of 450 ms in persons in their mid 70 years under some circumstances. QTc prolongation 〉 500 ms with antipsychotic drugs is more likely for persons with QTc initially at the 99th percentile. It may occur with Haloperidol which does not on average alter QTc. Conclusions The range of values for the QT interval in apparently normal older men or women, when combined with the range of expected QT interval changes induced by antipsychotic drugs, can readily be associated with prolonged QTc. Individuals with QTc at the 99th percentile may have serious QTc prolongation with antipsychotic drugs even those that are not usually associated with QTc prolongation.

关键词： Cardiac safety Antipsychotic drugs Psychotropic drugs QT interval Aging

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Selected gas response measurements using reduced graphene oxide decorated with nickel nanoparticles

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Nano materials Science 2021年第4期3卷 412-419页

作者： Ilka simon Yulyan Haiduk Rolf mtilhaupt Vladimir Pankov Christoph Janiak Institut für Anoganische Chemie und Strukturchemie Heinrich-Heine Universität Düsseldorf 40204DüsseldorfGermany Chemical Faculty Belarusian State UniversityLenningradskaya Str.14220050 MinskBelarus Freiburg materials Research Center and Institute for macromolecular Chemistry Albert-Ludwigs-UniversityFreiburg79104FreiburgGermany

The work reports the synthesis of nickel nanoparticles supported on thermally reduced graphene oxides(rGO)in the ionic liquid[BmIm][NTf_(2)]through microwave decomposition ***@rGO with the polymer poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)as binder was positively tested for its response towards the oxidizing gas nitrogen dioxide(10 ppm in air),the reducing gas carbon monoxide(3000 ppm in N_(2))and the volatile organic compound(VOC)acetone(35,000 ppm in air).The results from different gases were compared at different temperatures with the best results for NO_(2) at 200℃.Additionally,it is shown for NO_(2) gas that the Ni@rGO-PEDOT:PSS polymer composite gives better results than the rGO-PEDOT:PSS polymer *** the heat treatment the oxidation state of pure nickel nanoparticles were confirmed by powder diffraction.

关键词： Nickel nanoparticles Reduced graphene oxide Gas sensing Nanocomposite

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East African topography and volcanism explained by a single,migrating plume

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Geoscience Frontiers 2020年第5期11卷 1669-1680页

作者： Rakib Hassan simon E.Williams michael Gurnis Dietmar muller School of Geosciences Room 412Madsen Building F09 Eastern AvenueThe University of SydneyNSW2006Australia Seismological Laboratory California Institute of TechnologyPasadenaCA91125USA Now at Geoscience Australia GPO Box 378CanberraACT2601Australia State Key Laboratory of Continental Dynamics Department of GeologyNorthwest UniversityXi’an 710069China

Anomalous topographic swells and Cenozoic volcanism in east Africa have been associated with mantle *** models involving one or more fixed plumes beneath the northeastward migrating African plate have been suggested to explain the space-time distribution of magmatism in east *** devise paleogeographically constrained global models of mantle convection and,based on the evolution of flow in the deepest lower mantle,show that the Afar plume migrated southward throughout its *** models suggest that the mobile Afar plume provides a dynamically consistent explanation for the spatial extent of the southward propagation of the east African rift system(EARS),which is difficult to explain by the northeastward migration of Africa over one or more fixed plumes alone,over the last≈45 *** further show that the age-progression of volcanism associated with the southward propagation of EARS is consistent with the apparent surface hotspot motion that results from southward motion of the modelled Afar plume beneath the northeastward migrating African *** models suggest that the Afar plume became weaker as it migrated southwards,consistent with trends observed in the geochemical record.

关键词： Numerical mantle flow models Deep mantle flow LLSVP morphology Plume dynamics Plume motion Dynamic topography

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EPR and magnetic Susceptibility Studies of Cr^(3+) Ions in the 70TeO_2·25B_2O_3·5PbO Glass matrix

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Journal of materials Science & Technology 1997年第5期13卷 374-378页

作者： Peteanu m. simon V. muresan N. Ardelean I. Filip S. Faculty of Physics Babes-Bolyai University 3400 Cluj-Napoca Romania Dept. of Physics University of Oradea 3700 Oradea Romania

By using EPR and magnetic susceptibility measurements, the Cr ion distribution in the xCr2O3.(1-x)[70TeO2·25B2O3·5PbO] glasses with 0＜x≤20 mol% was studied. EPR investigation evidencedthe presence of Cr3+ ions in agreement with the experimentally obtained atomic magnetic moment values. For concentrations x≤3 mol%, the isolated Cr3+ ions coexist with those coupledby dipole-dipole interactions. For x＞3 mol%, the Cr3+ ions participate in superexchange interactions and are predominantly antiferromagnetically coupled.

关键词： PbO Ions in the 70TeO2 Glass matrix EPR and magnetic Susceptibility Studies of Cr Cr

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Intensity of parasitic infestation in silver carp,Hypophthalmichthys molitrix

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2012年第12期13卷 1024-1028页

作者： m.m.ALAm m.A.KHAN m.A.HUSSAIN D.mOUmITA A.G.mAZLAN K.D.simon Department of Fisheries University of RajshahiRajshahi 6205Bangladesh School of Environmental and Natural Resource Sciences Faculty of Science and TechnologyUniversiti Kebangsaan Malaysia43600 UKM BangiSelangorD.E.Malaysia

Silver carp,Hypopthalmichthys molitrix is one of the most economically valuable fish species in ***,its production is often hindered by parasite-induced *** present study reports the intensity of parasitic infestation in 216 specimens of *** collected from different fish markets in Rajshahi City,*** different parasite species (Trichodina pediculatus,Dactylogyrus vastator,Ichthyophthirius multifilis,Gyrodactylus elegans,Lernaea sp.,Apiosoma sp.,myxobolus rohitae,Camallanus ophiocephali,and Pallisentis ophiocephali) were recovered from the gill,skin,stomach,and intestine of host *** highest level of infection was observed for host skin,while lower levels were observed for host gill,stomach,and *** results also revealed that the intensity of parasite infection in different organs of *** varied with the *** particular,the highest levels of infection were recorded during the winter period (November-February),when fish are most susceptible to *** findings of the study will help in the management and conservation of ***.

关键词： Freshwater fish Disease Parasites Carpfishery Infestation Aquaculture Bangladesh

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deCS:A Tool for Systematic Cell Type Annotations of Single-cell RNA Sequencing Data among Human Tissues

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Genomics, Proteomics & Bioinformatics 2023年第2期21卷 370-384页

作者： Guangsheng Pei Fangfang Yan Lukas m.simon Yulin Dai Peilin Jia Zhongming Zhao Center for Precision Health School of Biomedical InformaticsThe University of Texas Health Science Center at HoustonHoustonTX 77030USA Therapeutic Innovation Center Baylor College of MedicineHoustonTX 77030USA Human Genetics Center School of Public HealthThe University of Texas Health Science Center at HoustonHoustonTX 77030USA mD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences HoustonTX 77030USA Department of Biomedical Informatics Vanderbilt University Medical CenterNashvilleTN 37203USA CAS Key Laboratory of Genomic and Precision medicine Beijing Institute of GenomicsChinese Academy of Sciences and China National Center for BioinformationBeijing 100101China

Single-cell RNA sequencing(scRNA-seq)is revolutionizing the study of complex and dynamic cellular ***,cell type annotation remains a main challenge as it largely relies on a priori knowledge and manual curation,which is cumbersome and *** increasing number of scRNA-seq datasets,as well as numerous published genetic studies,has motivated us to build a comprehensive human cell type reference ***,we present decoding Cell type Specificity(deCS),an automatic cell type annotation method augmented by a comprehensive collection of human cell type expression profiles and marker *** used deCS to annotate scRNAseq data from various tissue types and systematically evaluated the annotation accuracy under different conditions,including reference panels,sequencing depth,and feature selection *** results demonstrate that expanding the references is critical for improving annotation *** to many existing state-of-the-art annotation tools,deCS significantly reduced computation time and increased *** can be integrated into the standard scRNA-seq analytical pipeline to enhance cell type ***,we demonstrated the broad utility of deCS to identify trait-cell type associations in 51 human complex traits,providing deep insights into the cellular mechanisms underlying disease pathogenesis.

关键词： Cell type-specific enrichment analysis scRNA-seq Cell type annotation Trait-cell type association Cell typemarkergene

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Diphyllobothrium latum:A case of an incidental finding

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World Journal of Gastroenterology 2007年第12期13卷 1875-1876页

作者： simon Lal A Hillary Steinhart Department of Gastroenterology University Hospital Aintree Longmoor Lane Liverpool L9 7AL United Kingdom Department of Gastroenterology Mount Sinai Hospital University Avenue Toronto Ontario M5G 1X5 Canada

Colorectal cancer screening can be performed by fecal occult blood testing, sigmoidoscopy, double contrast barium enema or colonoscopy. Colonoscopy has the significant advantage that polyps can be removed during the same procedure. Occasionally, colonoscopy can also reveal unexpected findings, including parasitic infections, even in asymptomatic patients. Tapeworms or cestodes are hermaphroditic parasites, which can live for considerable periods of time in the human gastrointestinal tract. Fish tapeworm (Diphyllobothrium species) are endemic in various parts of the world, the commonest species being Diphyllobothrium latum. Humans are the main definitive host for D. Latum and the majority of individuals harbouring the parasite are asymptomatic, while 40% of infected individuals may have low vitamin B12 levels. We describe a case of D. latum infection found on routine colonoscopic screening for colorectal cancer in an asymptomatic patient, which was successfully treated with praziquantel. The infection likely arose following raw fish (sushi) consumption.

关键词： Diphyllobothrium latum Colonoscopy Colorectal cancer screening

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Axisymmetric alternating direction explicit scheme for efficient coupled simulation of hydro-mechanical interaction in geotechnical engineering-Application to circular footing and deep tunnel in saturated ground

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Journal of Rock mechanics and Geotechnical Engineering 2018年第2期10卷 259-279页

作者： simon Heru Prassetyo marte Gutierrez Department of Civil and Environmental Engineering Colorado School of MinesGoldenUSA mining Engineering Program Institut Teknologi BandungBandungIndonesia

Explicit solution techniques have been widely used in geotechnical engineering for simulating the coupled hydro-mechanical(H-m) interaction of fluid flow and deformation induced by structures built above and under saturated ground, i.e. circular footing and deep tunnel. However, the technique is only conditionally stable and requires small time steps, portending its inefficiency for simulating large-scale H-m problems. To improve its efficiency, the unconditionally stable alternating direction explicit(ADE)scheme could be used to solve the flow problem. The standard ADE scheme, however, is only moderately accurate and is restricted to uniform grids and plane strain flow conditions. This paper aims to remove these drawbacks by developing a novel high-order ADE scheme capable of solving flow problems in nonuniform grids and under axisymmetric conditions. The new scheme is derived by performing a fourthorder finite difference(FD) approximation to the spatial derivatives of the axisymmetric fluid-diffusion equation in a non-uniform grid configuration. The implicit Crank-Nicolson technique is then applied to the resulting approximation, and the subsequent equation is split into two alternating direction sweeps,giving rise to a new axisymmetric ADE scheme. The pore pressure solutions from the new scheme are then sequentially coupled with an existing geomechanical simulator in the computer code fast Lagrangian analysis of continua(FLAC). This coupling procedure is called the sequentially-explicit coupling technique based on the fourth-order axisymmetric ADE scheme or SEA-4-AXI. Application of SEA-4-AXI for solving axisymmetric consolidation of a circular footing and of advancing tunnel in deep saturated ground shows that SEA-4-AXI reduces computer runtime up to 42%-50% that of FLAC’s basic scheme without numerical instability. In addition, it produces high numerical accuracy of the H-m solutions with average percentage difference of only 0.5%-1.8%.

关键词： Hydro-mechanical(H-m) interaction Explicit coupling technique Alternating direction explicit(ADE) scheme High-order finite difference(FD) Non-uniform grid Axisymmetric consolidation Circular footing Deep tunnel in saturated ground

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