基于模糊集的陶质文物碎片点云特征提取算法

陶质文物碎片上同时包含尖锐特征和平滑特征,且文物碎片的原始表面并不光滑,因此,针对陶质文物碎片的散乱点云模型,该文提出一种鲁棒的特征提取方法。首先,基于法向估计和区域生长,建立一种基于模糊集的区域生长法,将每个潜在曲面划分成一个区域,区域间相交部分的点标记为潜在特征点。然后,将点在局部平面上的投影残差作为特征值,计算点在不同尺度下成为特征点的可能性进行特征提取。最后,采用“双生长圆”策略,生成特征折线,并对其进行平滑处理得到平滑特征线。实验结果表明,该方法稳定、抗噪性强,在有效提取尖锐特征的同时,还能尽可能多地保留较平滑的特征,针对各类模型,均能获得较好的效果。

Temperate Stutzerimonas Phage Encoding Toxin-Antitoxin System Genes Represents a Novel Genus

Stutzerimonas have been extensively studied due to their remarkable metabolic and physiological diversity.However,research on its phages is currently limited.In this study,we isolated a novel double-stranded DNA(dsDNA)phage,vB_SstM-PG1,from the marine environment that infects Stutzerimonas stutzeri G1.Its dsDNA genome is 37204 bp long with a G/C content of 64.14%and encodes 54 open reading frames.The phage possesses a tail packaging structure that is different from known Stutzerimonas stutzeri phages and exhibits structural protein characteristics similar to those of temperate phages.In addition,two genes of toxin-antitoxin system,including YdaS_antitoxin and HEPN_SAV_6107,were found in the vB_SstM-PG1 genome and play important roles in regulating host growth and metabolism.With phylogenetic tree and comparative genomic analysis,it has been determined that vB_SstM-PG1 is not closely related to any phages previously identified in the GenBank database.Instead,it has a connection with enigmatic,uncultured viruses.Specifically,the vB_SstM-PG1 virus exhibits an average nucleotide identity of over 70%with six uncultivated viruses identified in the IMG/VR v4 database.This significant finding has resulted in the identification of a novel viral genus known as Metabovirus.