The Application of Nicotiana benthamiana as a Transient Expression Host to Clone the Coding Sequences of Plant Genes

Coding sequences (CDS) are commonly used for transient gene expression, in yeast two-hybrid screening, to verify protein interactions and in prokaryotic gene expression studies. CDS are most commonly obtained using complementary DNA (cDNA) derived from messenger RNA (mRNA) extracted from plant tissues and generated by reverse transcription. However, some CDS are difficult to acquire through this process as they are expressed at extremely low levels or have specific spatial and/or temporal expression patterns in vivo. These challenges require the development of alternative CDS cloning technologies. In this study, we found that the genomic intron-containing gene coding sequences (gDNA) from Arabidopsis thaliana, Oryza sativa, Brassica napus, and Glycine max can be correctly transcribed and spliced into mRNA in Nicotiana benthamiana. In contrast, gDNAs from Triticum aestivum and Sorghum bicolor did not function correctly. In transient expression experiments, the target DNA sequence is driven by a constitutive promoter. Theoretically, a sufficient amount of mRNA can be extracted from the N. benthamiana leaves, making it conducive to the cloning of CDS target genes. Our data demonstrate that N. benthamiana can be used as an effective host for the cloning CDS of plant genes.

The global Antarctic Research event,SCAR 2024

We are pleased to announce that“The 11th SCAR Open Science Conference”will take place in Pucón,Chile from 19-23 August 2024,hosted by the Chilean Antarctic Institute.Detailed information at https://www.scar2024.org/.The 11th SCAR Open Science Conference theme“Antarctic Science:Crossroads for a New Hope”,recognizes the importance of Antarctica as a unique and fragile ecosystem.With increasing concerns about climate change and its impact on the polar regions,this theme aims to highlight the significance of Antarctic research in shaping our understanding of global environmental challenges.By fostering collaboration and knowledge exchange,the SCAR Open Science conference hopes to inspire new solutions and a renewed sense of hope for the future of our planet.

Endoscopic treatment of scarred polyps with a non-thermal device(Endorotor):A review of the literature

Endoscopic resection(ER)of colorectal polyps has become a daily practice in most endoscopic units providing a colorectal cancer screening program and requires the availability of local experts and high-end endoscopic devices.ER procedures have evolved over the past few years from endoscopic mucosal resection(EMR)to more advanced techniques,such as endoscopic submucosal dissection and endo-scopic full-thickness resection.Complete resection and disease eradication are the ultimate goals of ER-based techniques,and novel devices have been developed to achieve these goals.The EndoRotor®Endoscopic Powered Resection System(Interscope Medical,Inc.,Northbridge,Massachusetts,United States)is one such device.The EndoRotor is a powered resection tool for the removal of alimentary tract mucosa,including post-EMR persistent lesions with scarring,and has both CE Mark and FDA clearance.This review covers available published evidence documenting the usefulness of EndoRotor for the management of recurrent colorectal polyps.

Exploring the potential mechanism of WuFuYin against hypertrophic scar using network pharmacology and molecular docking

BACKGROUND Hypertrophic scar(HTS)is dermal fibroproliferative disorder,which may cause physiological and psychological problems.Currently,the potential mechanism of WuFuYin(WFY)in the treatment of HTS remained to be elucidated.AIM To explore the potential mechanism of WFY in treating HTS.METHODS Active components and corresponding targets were retrieved from the Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform.HTSrelated genes were obtained from the GeneCards,DisGeNET,and National Center for Biotechnology Information.The function of targets was analyzed by performing Gene Ontology and Kyoto Encyclopaedia of Genes and Genome(KEGG)enrichment analysis.A protein+IBM-protein interaction(PPI)network was developed using STRING database and Cytoscape.To confirm the high affinity between compounds and targets,molecular docking was performed.RESULTS A total of 65 core genes,which were both related to compounds and HTS,were selected from multiple databases.PPI analysis showed that CKD2,ABCC1,MMP2,MMP9,glycogen synthase kinase 3 beta(GSK3B),PRARG,MMP3,and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit gamma(PIK3CG)were the hub targets and MOL004941,MOL004935,MOL004866,MOL004993,and MOL004989 were the key compounds of WFY against HTS.The results of KEGG enrichment analysis demonstrated that the function of most genes were enriched in the PI3K-Akt pathway.Moreover,by performing molecular docking,we confirmed that GSK3B and 8-prenylated eriodictyol shared the highest affinity.CONCLUSION The current findings showed that the GSK3B and cyclin dependent kinase 2 were the potential targets and MOL004941,MOL004989,and MOL004993 were the main compounds of WFY in HTS treatment.

Phylogenetic, phylogeographic and divergence time analysis of Anopheles subpictus species complex using ITS2 and COI sequences

Objective:To address the phylogenetic and phylogeographic relationship between different lineages of Anopheles(An.)subpictus species complex in most parts of the Asian continent by maximum utilization of Internal Transcriber Spacer 2(ITS2)and cytochrome C oxidase I(COI)sequences deposited at the GenBank.Methods:Seventy-five ITS2,210 COI and 26 concatenated sequences available in the NCBI database were used.Phylogenetic analysis was performed using Bayesian likelihood trees,whereas median-joining haplotype networks and time-scale divergence trees were generated for phylogeographic analysis.Genetic diversity indices and genetic differentiation were also calculated.Results:Two genetically divergent molecular forms of An.subpictus species complex corresponding to sibling species A and B are established.Species A evolved around 37-82 million years ago in Sri Lanka,India,and the Netherlands,and species B evolved around 22-79 million years ago in Sri Lanka,India,and Myanmar.Vietnam,Thailand,and Cambodia have two molecular forms:one is phylogenetically similar to species B.Other forms differ from species A and B and evolved recently in the above mentioned countries,Indonesia and the Philippines.Genetic subdivision among Sri Lanka,India,and the Netherlands is almost absent.A substantial genetic differentiation was obtained for some populations due to isolation by large geographical distances.Genetic diversity indices reveal the presence of a long-established stable mosquito population,at mutation-drift equilibrium,regardless of population fluctuations.Conclusions:An.subpictus species complex consists of more than two genetically divergent molecular forms.Species A is highly divergent from the rest.Sri Lanka and India contain only species A and B.

南沙群岛珊瑚礁区黑斑鹦嘴鱼(Scarus globiceps)食性分析

鹦嘴鱼科(Scaridae)鱼类参与珊瑚礁生态系统诸多关键生态过程,在维持珊瑚礁生态系统稳定与平衡中发挥着重要作用。由于以往研究手段的限制,对鹦嘴鱼的食物来源及生态功能价值认识不足,在其功能定位方面存在较多争议。本研究选择珊瑚分布的典型区域—南沙群岛中的东门礁和南薰礁为研究海域,对该海域鹦嘴鱼优势种类黑斑鹦嘴鱼(Scarus globiceps)摄食的藻类多样性进行全面分析。通过18S rDNA和16S rDNA多基因条形码技术,分别对黑斑鹦嘴鱼肠含物的真核藻类和原核藻类DNA进行高通量测序分析。18S rDNA的测序结果发现,黑斑鹦嘴鱼类的肠含物中真核藻类以甲藻(Dinoflagellata)、红藻(Rhodophyta)、绿藻(Chlorophyta)、褐藻(Ochrophyta)为主,共计77个OTU(operational taxonomic units)。甲藻相对序列丰度和多样性较高,序列比例占真核藻类序列总数的51.42%,其中网甲藻科(Suessiaceae)OTU_5在东门礁和南薰礁的样品中均超过20%。16S rDNA测序鉴定发现肠含物含有原核藻类(蓝藻)的序列,共计21个OTU,其中以念珠藻目(Nostocales)的相对序列丰度最高,达到39.33%。本研究表明,黑斑鹦嘴鱼在摄食过程中会摄入一定量大型藻类,但微藻(甲藻)序列占据优势地位,蓝藻在肠含物中也有较高的检出率,说明需要重新考虑微藻(甲藻和蓝藻)在鹦嘴鱼食源中的重要贡献以及对珊瑚礁生态系统结构与功能的影响。

Landscape of Sequence Variations in Homologous Copies of FAD2 and FAD3 in Rapeseed(Brassica napus L.)Germplasm with High/Low Linolenic Acid Trait

Genetic manipulation(either restraint or enhancement)of the biosynthesis pathway ofα-linolenic acid(ALA)in seed oil is an important goal in Brassica napus breeding.B.napus is a tetraploid plant whose genome often har-bors four and six homologous copies,respectively,of the two fatty acid desaturases FAD2 and FAD3,which con-trol the last two steps of ALA biosynthesis during seed oil accumulation.In this study,we compared their promoters,coding sequences,and expression levels in three high-ALA inbred lines 2006L,R8Q10,and YH25005,a low-ALA line A28,a low-ALA/high-oleic-acid accession SW,and the wildtype ZS11.The expression levels of most FAD2 and FAD3 homologs in the three high-ALA accessions were higher than those in ZS11 and much higher than those in A28 and SW.The three high-ALA accessions shared similar sequences with the pro-moters and CDSs of BnFAD3.C4 and BnFAD3.A3.In A28 and SW,substitution of three amino acid residues in BnFAD2.A5 and BnFAD2.C5,an absence of BnFAD2.C1 locus,and a 549 bp long deletion on the BnFAD3.A3 promoter were detected.The profile of BnFAD2 mutation in the two low-ALA accessions A28 and SW is different from that reported in previous studies.The mutations in BnFAD3 in the high-ALA accessions are reported for thefirst time.In identifying the sites of these mutations,we provide detailed information to aid the design of mole-cular markers for accelerated breeding schemes.

Secure Transmission of Compressed Medical Image Sequences on Communication Networks Using Motion Vector Watermarking

Medical imaging plays a key role within modern hospital management systems for diagnostic purposes.Compression methodologies are extensively employed to mitigate storage demands and enhance transmission speed,all while upholding image quality.Moreover,an increasing number of hospitals are embracing cloud computing for patient data storage,necessitating meticulous scrutiny of server security and privacy protocols.Nevertheless,considering the widespread availability of multimedia tools,the preservation of digital data integrity surpasses the significance of compression alone.In response to this concern,we propose a secure storage and transmission solution for compressed medical image sequences,such as ultrasound images,utilizing a motion vector watermarking scheme.The watermark is generated employing an error-correcting code known as Bose-Chaudhuri-Hocquenghem(BCH)and is subsequently embedded into the compressed sequence via block-based motion vectors.In the process of watermark embedding,motion vectors are selected based on their magnitude and phase angle.When embedding watermarks,no specific spatial area,such as a region of interest(ROI),is used in the images.The embedding of watermark bits is dependent on motion vectors.Although reversible watermarking allows the restoration of the original image sequences,we use the irreversible watermarking method.The reason for this is that the use of reversible watermarks may impede the claims of ownership and legal rights.The restoration of original data or images may call into question ownership or other legal claims.The peak signal-to-noise ratio(PSNR)and structural similarity index(SSIM)serve as metrics for evaluating the watermarked image quality.Across all images,the PSNR value exceeds 46 dB,and the SSIM value exceeds 0.92.Experimental results substantiate the efficacy of the proposed technique in preserving data integrity.

Method and Description of Sedimentary System Characterization Based on Sequence Stratigraphy

A Oilfield is the most representative mid to deep oil field in the Bohai Sea, with the main oil bearing intervals being the upper and middle Shahejie-3 sections of the Paleogene Shahejie Formation. By combining well seismic analysis, the middle section of Shahejie-3 is divided into high-level system tract and forced lake retreat system tract, corresponding to the II oil formation and I oil formation, respectively. Using sequence stratigraphy methods, based on seismic profiles and drilling lithological cycles, the high stand system tract is divided into 5 stages of delta progradation. The first and second stages are high angle S-type progradation with large sedimentary thickness, the third stage is oblique progradation, and the fourth and fifth stages are S-oblique composite progradation;By combining seismic data, we characterized the large-scale (8 small-scale) progradation bodies of 5 periods, clarified the distribution characteristics of reservoir planes, and laid the foundation for the later exploration of oilfield potential.

Coseismic Coulomb stress changes induced by a 2020-2021 M_(W)>7.0 Alaska earthquake sequence in and around the Shumagin gap and its influence on the Alaska-Aleutian subduction interface

Three M_(W)>7.0 earthquakes in 2020-2021 occurred in the Shumagin seismic gap and its adjacent area of the Alaska-Aleutian subduction zone,including the Mw7.8 Simeonof thrust earthquake on July 22,2020,the M_(W)7.6 Sand Point strike-slip earthquake on October 19,2020,and the M_(W)8.2 Chignik thrust earthquake on July 29,2021.The spatial and temporal proximity of these three earthquakes prompts us to probe stress-triggering effects among them.Here we examine the coseismic Coulomb stress change imparted by the three earthquakes and their influence on the subduction interface.Our results show that:(1)The Simeonof earthquake has strong loading effects on the subsequent Sand Point and Chignik earthquakes,with the Coulomb stress changes of 3.95 bars and 2.89 bars,respectively.The Coulomb stress change caused by the Sand Point earthquake at the hypocenter of the Chignik earthquake is merely around 0.01 bars,suggesting the negligible triggering effect on the latter earthquake;(2)The triggering effects of the Simeonof,Sand Point,and Chignik earthquakes on aftershocks within three months are not well pronounced because of the triggering rates of 38%,14%,and 43%respectively.Other factors may have played an important role in promoting the occurrence of these aftershocks,such as the roughness of the subduction interface,the complicated velocity structure of the lithosphere,and the heterogeneous prestress therein;(3)The three earthquakes caused remarkable coseismic Coulomb stress changes at the subduction interface nearby these mainshocks,with an average Coulomb stress change of 3.2 bars in the shallow region directly inwards the trench.

Intelligent extraction of road cracks based on vehicle laser point cloud and panoramic sequence images

In light of the limited efficacy of conventional methods for identifying pavement cracks and the absence of comprehensive depth and location data in two-dimensional photographs,this study presents an intelligent strategy for extracting road cracks.This methodology involves the integration of laser point cloud data obtained from a vehicle-mounted system and a panoramic sequence of images.The study employs a vehicle-mounted LiDAR measurement system to acquire laser point cloud and panoramic sequence image data simultaneously.A convolutional neural network is utilized to extract cracks from the panoramic sequence image.The extracted sequence image is then aligned with the laser point cloud,enabling the assignment of RGB information to the vehicle-mounted three dimensional(3D)point cloud and location information to the two dimensional(2D)panoramic image.Additionally,a threshold value is set based on the crack elevation change to extract the aligned roadway point cloud.The three-dimensional data pertaining to the cracks can be acquired.The experimental findings demonstrate that the use of convolutional neural networks has yielded noteworthy outcomes in the extraction of road cracks.The utilization of point cloud and image alignment techniques enables the extraction of precise location data pertaining to road cracks.This approach exhibits superior accuracy when compared to conventional methods.Moreover,it facilitates rapid and accurate identification and localization of road cracks,thereby playing a crucial role in ensuring road maintenance and traffic safety.Consequently,this technique finds extensive application in the domains of intelligent transportation and urbanization development.The technology exhibits significant promise for use in the domains of intelligent transportation and city development.

Influence of Production Sequence of Aluminum Alloy Hot Rolling on Strip Surface Quality

With the intensification of market competition in the aluminum alloy strip processing industry,it is dif-ficult to control the mass production of the same specifications,which is bound to affect the hot rolling production.This paper studied the effect of the hot rolling order of aluminum alloy on the surface quality of strip,such as roll printing,color difference,anodic oxidation,etc.,reasonable discharge sequence and corresponding optimization measures were formulated.

通过改良RAPD技术获得黑毛石斛、蜂腰石斛和石仙桃的3条SCAR新标记

目的寻找快速区分黑毛石斛、蜂腰石斛和石仙桃的序列特征扩增区域(sequence characterized amplified regions,SCAR)新标记。方法在改良的随机扩增多态性DNA(random amplified polymorphic DNA,RAPD)的基础上对10个物种进行基因组DNA随机扩增、分子克隆和测序,分别设计了可鉴别3个物种的SCAR标记。结果成功筛选出3个SCAR标记,其相应的特异性标记分别为N2-12、A2-17和A6-33;其中SCAR标记N2-12在黑毛种属中扩增出约750 bp的特异性条带,SCAR标记A2-17在蜂腰石斛中扩增出约750 bp的特异性条带,SCAR标记A6-33在石仙桃种属中扩增出约600 bp的特异性条带。结论N2-12、A2-17和A6-33这3对特异性SCAR新标记能快速、准确的区分出黑毛石斛、蜂腰石斛和石仙桃这3个物种,为今后进行该中药道地药材样品的鉴定提供了实验依据。

Development of a stable SCAR marker for rapid identification of Ganoderma lucidum Hunong 5 cultivar using DNA pooling method and inter-simple sequence repeat markers

The cultivar Ganoderma lucidum Hunong 5 was obtained using cross-breeding. Hunong 5 has high commercial value due to its high polysaccharide and triterpene content, This is the first report of using a DNA pooling method to develop a stable sequence characterized amplified region （SCAR） marker for rapid identification of the G. lucidum Hunong 5 cultivar. The SCAR marker was developed by first generating and sequencing a distinctive inter simple sequence repeat （ISSR） fragment （882 bp） from G. lucidum Hunong 5 cultivar. A stable SCAR primer pair GLH5F/GLH5R were obtained to identify the cultivar and the SCAR marker is a DNA fragment of 773 bp.

Development of Sequence Characterized Amplified Region (SCAR) Primers for the Detection of Resistance to Sporisorium reiliana in Maize

Head smut of maize （Zea mays L.）, which was caused by Sporisorium reiliana, occurred in most of the maize growing areas of the world. The purpose of this study was to develop SCAR markers for map-based cloning of resistance genes and MAS. Two sets of BC3 progenies, one （BC3Q） derived from the cross Qi319 （resistance）×Huangzao 4 （susceptible）, the other （BC3M） from Mol7 （resistance）× Huangzao 4 （susceptible）, were generated. Huangzao 4 was the recurrent parent in both progenies. A combination of BSA （bulked segregant analysis） with AFLP （amplified fragment length polymorphism） method was applied to map the genes involving the resistance to S. reiliana, and corresponding resistant and susceptible bulks and their parental lines were used for screening polymorphic AFLP primer pairs. One fragment of PI3M61-152 was converted into SCAR （sequence charactered amplified fragment） marker S130. The marker was mapped at chromosome bin 2.09, the interval of a major QTL region previously reported to contribute to S. reiliana resistance. Furthermore, S130 was highly and facilitate map-based cloni associated with resistance to S. reiliana, and could be useful for marker-assisted selection ng of resistance genes.

Microglial depletion impairs glial scar formation and aggravates inflammation partly by inhibiting STAT3 phosphorylation in astrocytes after spinal cord injury

Astrocytes and microglia play an orchestrated role following spinal cord injury;however,the molecular mechanisms through which microglia regulate astrocytes after spinal cord injury are not yet fully understood.Herein,microglia were pharmacologically depleted and the effects on the astrocytic response were examined.We further explored the potential mechanisms involving the signal transducers and activators of transcription 3(STAT3)pathway.For in vivo experiments,we constructed a contusion spinal cord injury model in C57BL/6 mice.To deplete microglia,all mice were treated with colony-stimulating factor 1 receptor inhibitor PLX3397,starting 2 weeks prior to surgery until they were sacrificed.Cell proliferation was examined by 5-ethynyl-2-deoxyuridine(EdU)and three pivotal inflammatory cytokines were detected by a specific Bio-Plex Pro^(TM) Reagent Kit.Locomotor function,neuroinflammation,astrocyte activation and phosphorylated STAT3(pSTAT3,a maker of activation of STAT3 signaling)levels were determined.For in vitro experiments,a microglia and astrocyte coculture system was established,and the small molecule STA21,which blocks STAT3 activation,was applied to investigate whether STAT3 signaling is involved in mediating astrocyte proliferation induced by microglia.PLX3397 administration disrupted glial scar formation,increased inflammatory spillover,induced diffuse tissue damage and impaired functional recovery after spinal cord injury.Microglial depletion markedly reduced EdU+proliferating cells,especially proliferating astrocytes at 7 days after spinal cord injury.RNA sequencing analysis showed that the JAK/STAT3 pathway was downregulated in mice treated with PLX3397.Double immunofluorescence staining confirmed that PLX3397 significantly decreased STAT3 expression in astrocytes.Importantly,in vitro coculture of astrocytes and microglia showed that microglia-induced astrocyte proliferation was abolished by STA21 administration.These findings suggest that microglial depletion impaired astrocyte proliferation and astrocytic scar formation,and induced inflammatory diffusion partly by inhibiting STAT3 phosphorylation in astrocytes following spinal cord injury.

Improving the accuracy of genomic prediction for meat quality traits using whole genome sequence data in pigs

Background Pork quality can directly affect customer purchase tendency and meat quality traits have become valu-able in modern pork production.However,genetic improvement has been slow due to high phenotyping costs.In this study,whole genome sequence(WGS)data was used to evaluate the prediction accuracy of genomic best linear unbiased prediction(GBLUP)for meat quality in large-scale crossbred commercial pigs.Results We produced WGS data(18,695,907 SNPs and 2,106,902 INDELs exceed quality control)from 1,469 sequenced Duroc×(Landrace×Yorkshire)pigs and developed a reference panel for meat quality including meat color score,marbling score,L*(lightness),a*(redness),and b*(yellowness)of genomic prediction.The prediction accuracy was defined as the Pearson correlation coefficient between adjusted phenotypes and genomic estimated breeding values in the validation population.Using different marker density panels derived from WGS data,accuracy differed substantially among meat quality traits,varied from 0.08 to 0.47.Results showed that MultiBLUP outperform GBLUP and yielded accuracy increases ranging from 17.39%to 75%.We optimized the marker density and found medium-and high-density marker panels are beneficial for the estimation of heritability for meat quality.Moreover,we conducted genotype imputation from 50K chip to WGS level in the same population and found average concord-ance rate to exceed 95%and r^(2)=0.81.Conclusions Overall,estimation of heritability for meat quality traits can benefit from the use of WGS data.This study showed the superiority of using WGS data to genetically improve pork quality in genomic prediction.

M2 macrophages mediate fibrotic scar formation in the early stages after cerebral ischemia in rats

In the central nervous system, the formation of fibrotic scar after injury inhibits axon regeneration and promotes repair. However, the mechanism underlying fibrotic scar formation and regulation remains poorly understood. M2 macrophages regulate fibrotic scar formation after injury to the heart, lung, kidney, and central nervous system. However, it remains to be clarified whether and how M2 macrophages regulate fibrotic scar formation after cerebral ischemia injury. In this study, we found that, in a rat model of cerebral ischemia induced by middle cerebral artery occlusion/reperfusion, fibrosis and macrophage infiltration were apparent in the ischemic core in the early stage of injury(within 14 days of injury). The number of infiltrated macrophages was positively correlated with fibronectin expression. Depletion of circulating monocyte-derived macrophages attenuated fibrotic scar formation. Interleukin 4(IL4) expression was strongly enhanced in the ischemic cerebral tissues, and IL4-induced M2 macrophage polarization promoted fibrotic scar formation in the ischemic core. In addition, macrophage-conditioned medium directly promoted fibroblast proliferation and the production of extracellular matrix proteins in vitro. Further pharmacological and genetic analyses showed that sonic hedgehog secreted by M2 macrophages promoted fibrogenesis in vitro and in vivo, and that this process was mediated by secretion of the key fibrosis-associated regulatory proteins transforming growth factor beta 1 and matrix metalloproteinase 9. Furthermore, IL4-afforded functional restoration on angiogenesis, cell apoptosis, and infarct volume in the ischemic core of cerebral ischemia rats were markedly impaired by treatment with an sonic hedgehog signaling inhibitor, paralleling the extent of fibrosis. Taken together, our findings show that IL4/sonic hedgehog/transforming growth factor beta 1 signaling targeting macrophages regulates the formation of fibrotic scar and is a potential therapeutic target for ischemic stroke.

A Novel Method of Deinterleaving Radar Pulse Sequences Based on a Modified DBSCAN Algorithm

A modified DBSCAN algorithm is presented for deinterleaving of radar pulses in modern EW environments.A main characteristic of the proposed method is that using only time of arrival of pulses,the method can sort the pulses efficiently.Other PDW information such as rise time,carrier frequency,pulse width,modulation on pulse,fall time and direction of arrival are not required.To identify the valid PRIs in a set of interleaved pulses,an innovative modification of the DBSCAN algorithm is introduced which is accurate and easy to implement.The proposed method determines valid PRIs more accurately and neglects the spurious ones more efficiently as compared to the classical histogram based algorithms such as SDIF.Furthermore,without specifying any input parameter,the proposed method can deinterleave radar pulses while up to 30%jitter is present in the associated PRI.The accuracy and efficiency of the proposed method are verified by computer simulations and real data results.Experimental simulations are based on different real and operational scenarios where the presence of missing and spurious pulses are also considered.So,the simulation results can be of practical significance.

基于sCARS-PSO-SVM的土壤硒含量高光谱定量反演

硒(Se)是人体必需的微量元素之一。人主要通过食用农产品来获取硒,而农产品中的硒主要来自土壤。因此,研究土壤中硒的含量和分布,对人体健康和农作物生产具有重要的意义。高光谱遥感技术的发展,使得高效、低成本、大范围估测土壤中硒的含量和分布成为可能。但是,土壤中硒的含量对光谱的敏感性较弱,严重影响了高光谱硒含量定量反演精度。该研究以广东连州地区富硒土壤为研究对象,系统采集研究区土壤样品50份,分析土壤样本硒含量,同步采集土壤反射光谱数据;利用Savitzky-Golay卷积平滑算法、多元散射校正(MSC)、对数一阶微分(lg(R)-FD)、标准正态变量校正(SNV)、多元散射校正一阶微分(MSC-FD)对原始光谱进行增强处理;应用稳定竞争自适应重加权采样(sCARS)算法结合皮尔逊相关性分析(PCC)进行特征波段选择;对比分析偏最小二乘(PLS)、支持向量机(SVM)和粒子群优化支持向量(PSO-SVM)模型土壤硒含量高光谱定量反演效果。结果表明:将sCARS算法应用于光谱增强后的回归模型,并结合皮尔逊相关性(PCC)选择与土壤硒含量敏感性较大的特征波段,不仅可以降低土壤硒含量高光谱预测模型复杂度并有效避免大量有用信息的损失,还能提高高光谱回归模型的反演效率;对比不同回归模型训练集和预测集的决定系数R^(2)和均方根误差RMSE,发现支持向量(SVM)模型比偏最小二乘(PLSR)模型预测效果更好,模型稳定性更高,且非线性模型更适用于土壤硒含量的预测;通过粒子群(PSO)算法优化SVM的核函数和正则化参数,SVM模型的反演精度和稳定性都有所提升;MSC-PSO-SVM模型(R^(2)=0.53、RMSE=0.34)和MSC-FD模型(R^(2)=0.50、RMSE=0.04)预测效果较为突出。综上所述:利用sCARS结合PSO-SVM算法建立土壤硒含量的高光谱定量反演模型,能够为土壤硒含量的高光谱大面积估测提供新的途径。