基于改进YOLOv8的轻量化小麦病害检测方法

为提高小麦病害检测精度,实现将模型方便快速部署到移动端,该研究提出了一种基于改进YOLOv8的轻量化小麦病害检测方法。首先,使用PP-LCNet模型替换YOLOv8网络结构的骨干网络,并在骨干网络层引入深度可分离卷积(depthwise separable convolution, DepthSepConv)结构,减少模型参数量,提升模型检测性能;其次,在颈部网络部分添加全局注意力机制(global attention mechanism, GAM)模块,强化特征中语义信息和位置信息,提高模型特征融合能力;然后,引入轻量级通用上采样内容感知重组(content-aware reassembly of features,CARAFE)模块,提高模型对重要特征的提取能力;最后,使用Wise-IoU(weighted interpolation of sequential evidence for intersection over union)边界损失函数代替原损失函数,提升网络边界框回归性能和对小目标病害的检测效果。试验结果表明,对于大田环境下所采集的小麦病害数据集,改进后模型的参数量及模型大小相比原YOLOv8n基线模型分别降低了12.5%和11.3%,同时精确度(precision)及平均精度均值(mean average precision,m AP)相较于原模型分别提高了4.5和1.9个百分点,优于其他对比目标检测算法,可为小麦病害检测无人机等移动端检测装备的部署和应用提供参考。

江铃福特途睿欧 和平共处

话说福特自从N年前引进麦柯斯之后在MPV市场上并无作为(商用车除外),如今二胎政策的放宽以及专车市场的崛起使得7座车型变得火热起来.受制于车辆的构造,虽然SUV也拥有7座,但并不能兼顾到车上的每一名乘客,所以要让车上的每一名乘客都'和平共处',MPV则具有先天优势,途睿欧正好能满足这部分人的需求.

Synergistic effect of bromocriptine and tumor necrosis factor-a on reversing hepatoceiiuiar carcinoma multidrug resistance in nude mouse MDRl model of liver neoplasm

AIM： To investigate the effect of bromocripUne （BCT） and tumor necrosis factor-α ClNF-α） on hepatocellular carcinoma （HCC） multidrug resistance （MDR） in nude mouse HDR model of liver neoplasm. METHODS： Human hepatocarcinoma cell line HepG2t drug resistant hepatocarcinoma cell line HepG2/adriamycin （ADM） and hepatocarcinoma cell line transfected with TNF-α gene HepG2JADM/TNF were injected into the liver of nude mice via orthotopic implantation and MDR model of liver neoplasm in vivo was established （HepG2t ADM, TNF, BCT groups）. Among these groups, BCT group and TNF group were treated with BCT through gastric canal. Each group was divided into control group and chemotherapy group. Size and weight of the tumor were measured. Furthermore, tumor his^logical character and growth of the nude mice were observed and their chemosensitivity was tested. MDR-associated genes and proteins （MRP, LRP） of implanted tumors were detected by immunohistochemistry, reverse transcriptase polymerase chain reaction, and apoptosis rate of hepatocarcinoma cells was detected by TUNEL assay. RESULTS： The nude mouse model of each cell line was inoculated successfully. The tumor growth rate and weight were significantly different among groups. After chemotherapy, abdominal cavity tumor growth inhibition rate was higher in BCT group （67%） compared to ADM and TNF groups, and similar to HepG2group （54%）. MDRI and LRPmRNA could be detected in all groups, but TNF-α was detected only in TNF and BCT groups. Furthermore, MDR1 and LRP protein expression of tumors in TNF and BCT groups was low similar to HepG2 group. The apoptosis rate of hepatocarcinoma cells was much higher in BCT group than in other groups with TUNEL assay. CONCLUSION： BCT and TNF-a can reverse HCC MDR in nude mouse MDR1 model of liver neoplasm. 2005 The WJG Press and Elsevier Inc. All rights reserved

Cloning and Phylogenetic Analysis of Ubiquitinconjugating Enzyme Gene TaUBC4 in Different Wheat Cultivars

[Objective] This study aimed to clone ubiquitin-conjugating enzyme gene TaUBC4 from different wheat cultivars and thus analyze their phylogenetic relationship.[Method] The UBC4 coding sequences were cloned through reverse transcription PCR （RT-PCR） from 21 wheat varieties.After sequencing,the UBC4 sequence in wheat cultivar Zhongguochun （GenBank accession No：M28059） was selected as the reference gene,to analyze the mutation frequency and evolutionary distance in the CDSs and corresponding amino acid sequences of the different wheat cultivars.Moreover,the phylogenetic tree based on the amino acid sequences of these TaUBC4 genes were constructed,involving the homologous sequences of TaUBC4 in eight other monocots.[Result] TaUBC4 sequence was highly conserved because the similarity in DNA sequences of the wheat varieties was over 94％,while that in amino acid sequence was over 96％.And the amino acid sequence difference only can be seen at two sites among some varieties.Phylogenetic tree constructed revealed the evolutionary relationships among these wheat varieties.[Conclusion] This study reveals the polymorphism and evolutionary characteristics in the nucleotide and amino acid sequences in different wheat varieties,which lays foundation for investigating the evolution and biological function of TaUBC4 gene.In addition,the phylogenetic tree constructed provides theoretical references for the classification of the wheat varieties with complicated background.

Evolution of 5S rRNA Genes in Ophiopogon xylorrhizus Wang et Dai and O. sylvicola Wang et Tang (Convallariaceae)

To reveal how a large gene family evolved in the highly organized genome, the present study sequenced 294 copies of 5S rRNA genes from six individuals of three populations of Ophiopogon xylorrhizus Wang et Dai, and 45 copies from its closest species, O. sylvicola Wang et Tang. Based on the sequences the gene-phylogeny was inferred through PAUP. The sequences were highly diversified. Of the 339 randomly cloned copies, only 13 pairs (3.8%) were identical, with length varied between 307 - 548 bp (average 438.6 bp). The sequence differentiation index (SDI) in O. xylorrhints was 0.078, in O. sylvicola was 0.032, and between these two species was 0.149. In the most parsimonious tree reconstructed, all of the 294 copies of O. xylorrhizus were grouped into one clade, and those of O. sylvicola were grouped into another clade with 100% bootstrap support. The result demonstrated that the copies of 5S rRNA genes originated from just one progenitor copy, 'founder copy', in both of the species respectively, followed by a series of proliferation, and little, if any, homogenization ever occurred in the copies. As the common ancestor of the two species must have home multiple copies of the genes, all the other copies were lost during or after the speciation. Additionally, the phylogeny clearly showed that the founder copy was proliferated continuously through time, not just once. O. xylorrhizus is an extremely endangered species in which high genetic diversity, selfing and depression on seedlings were observed previously. In our study the sequences from different populations or different individuals were mixed in the branches of the O. xylorrhizus clade, although they evolved independently. It is assumed that gene flow of the species happened much more frequently in the past, making the proliferated copies dispersed to different populations, and the species maintained an amount of genetic diversity. Therefore, the selfing and seedling depression would be the result of a recent event. We suggest that some changes in outer mechanisms, such as the pollinators or seed-dispersers, might cause the species selfed, depressed and, finally, endangered.

Boundary conditions: An effect of average of microscopic Maxwell’s equations

It is well known that the macroscopic Maxwell’s equations can be obtained from the corresponding microscopic or atomic equations by a proper averaging process. The purpose of this paper is to present the macroscopic Maxwell’s equations which are valid in all regions of space, including an interface between two different media; and the boundary conditions can naturally emerge from the macroscopic equations as an effect of average of the microscopic Maxwell’s equations. In addition, the application of the unit step functions and the Dirac delta function to our discussion not only permits great mathematical simplicity but also gives rise to convenient physical concepts for the description and representation of the actual fields in the vicinity of the interface.

A genome-wide analysis of the ASYMMETRIC LEAVES2/LATERAL ORGAN BOUNDARIES(AS2/LOB) gene family in barley(Hordeum vulgare L.)

ASYMMETRIC LEAVES2/LATERAL ORGAN BOUNDARIES（AS2/LOB） genes are a family of plant specific transcription factors, which play an important role in the regulation of plant lateral organ development and metabolism. However, a genome-wide analysis of the AS2/LOB gene family is still not available for barley. In the present study, 24 AS2-like（ASL）/LOB domain（LBD） genes were identified based on the barley（Hordeum vulgare L.） genome sequence. A phylogenetic tree of ASL/LBD proteins from barley, Arabidopsis, maize, and rice was constructed. The ASL/LBD genes were classified into two classes, class I and class II, which were divided into five and two subgroups, respectively. Genes homologous in barley and Arabidopsis were analyzed. In addition, the structure and chromosomal locations of the genes were analyzed. Expression profiles indicated that barley HvA SL/LBD genes exhibit a variety of expression patterns, suggesting that they are involved in various aspects of physiological and developmental processes. This genome-wide analysis of the barley AS2/LOB gene family contributes to our understanding of the functions of the AS2/LOB gene family.