主流媒体短视频传播中的国家形象建构研究——以中国网短视频节目《中国三分钟(China Mosaic)》为例

以中国网账号发布在境外社交媒体平台Facebook上的节目《中国三分钟(China Mosaic)》为例,使用Python工具软件抓取得到评论数据样本,能很好地分析海外受众对主题类型的关注偏向和态度取向。从整体上看,海外受众对我国国家形象呈现出积极认可的态度,主要表现为:高度肯定我国的经济实力和科教发展成果,赞许我大国外交所起到的作用和经济建设成就,向往中华优秀传统文化等。但由于意识形态、东西方认知的差异,在海外受众的评论中也存在一些杂音,需要我们理性对待、主动消弭。在对外传播中,要用海外受众乐于接受的话语表达方式、共通的符号,从大处着眼、小处入手讲述中国故事,掌握议题设置的主动权,传播好中国声音。

MOSAiC现场观测期间海冰厚度季节变化模拟误差分析

北极气候研究多学科漂流观测计划(Multidisciplinary drifting Observatory for the Study of Arctic Climate, MOSAiC)于2019年10月至2020年9月开展,期间获得了变量完整的大气、海洋、海冰厚度及积雪厚度观测,为海冰模式的发展提供了新的契机。本研究利用两个完整观测时段(2019年11月1日至2020年5月7日、2020年6月26日至7月27日)的大气和海洋强迫场,驱动一维海冰柱模式ICEPACK,模拟了MOSAiC期间海冰厚度的季节演变,同海冰厚度观测进行了对比,并诊断分析了海冰厚度模拟误差的原因。结果表明,在冬春季节,模式可以再现海冰厚度增长过程,但由于模式在春季高估了积雪向海冰的转化及对海冰物质平衡的贡献,模拟的春季海冰厚度偏厚。在夏季期间,2种热力学方案及3种融池方案的组合都表明模式高估了海冰表层的消融过程,导致模拟结束阶段的海冰厚度偏薄。我们的研究表明,使用变量完整的MOSAiC大气和海洋强迫场可以诊断目前海冰模式中的问题,为海冰模式的改进奠定基础。

Development of a stable attenuated double-mutant of tobacco mosaic virus for cross-protection

Tobacco(Nicotiana tabacum)and tomato(Solanum lycopersicum)are two major economic crops in China.Tobacco mosaic virus(TMV;genus Tobamovirus)is the most prevalent virus infecting both crops.Currently,some widely cultivated tobacco and tomato cultivars are susceptible to TMV and there is no effective strategy to control this virus.Cross-protection can be a safe and environmentally friendly strategy to prevent viral diseases.However,stable attenuated TMV mutants are scarce.In this study,we found that the substitutions in the replicase p126,arginine at position 196(R^(196))with aspartic acid(D),glutamic acid at position 614(E^(614))with glycine(G),serine at position 643(S^(643))with phenylalanine(F),or D at position 730(D^(730))with S,significantly reduced the virulence and replication of TMV.However,only the mutation of S^(643) to F reduced the RNA silencing suppression activity of TMV p126.A double-mutant TMV-E614G-S643F induced no visible symptom and was genetically stable through six successive passages in tobacco plants.Furthermore,our results showed that TMV-E614G-S643F double-mutant could provide effective protection against the wild-type TMV infection in tobacco and tomato plants.This study reports a promising mild mutant for cross-protection to control TMV in tobacco and tomato plants.

CRISPR/CasRx-mediated resistance to Soybean mosaic virus in soybean

Soybean mosaic virus(SMV),an RNA virus,is the most common and destructive pathogenic virus in soybean fields.The newly developed CRISPR/Cas immune system has provided a novel strategy for improving plant resistance to viruses;hence,this study aimed to engineer SMV resistance in soybean using this system.Specifically,multiple sgRNAs were designed to target positive-and/or negative-sense strands of the SMV HC-Pro gene.Subsequently,the corresponding CRISPR/CasRx vectors were constructed and transformed into soybeans.After inoculation with SMV,39.02%,35.77%,and 18.70%of T_(1)plants were confirmed to be highly resistant(HR),resistant(R),and mildly resistant(MR)to SMV,respectively,whereas only 6.50%were identified as susceptible(S).Additionally,qRT-PCR and DAS-ELISA showed that,both at 15 and 30 d post-inoculation(dpi),SMV accumulation significantly decreased or was even undetectable in HR and R plants,followed by MR and S plants.Additionally,the expression level of the CasRx gene varied in almost all T_(1)plants with different resistance level,both at 15 and 30 dpi.Furthermore,when SMV resistance was evaluated in the T_(2)generation,the results were similar to those recorded for the T_(1)generation.These findings provide new insights into the application of the CRISPR/CasRx system for soybean improvement and offer a promising alternative strategy for breeding for resistance to biotic stress that will contribute to the development of SMV-immune soybean germplasm to accelerate progress towards greater soybean crop productivity.

Turnip mosaic virus pathogenesis and host resistance mechanisms in Brassica

Turnip mosaic virus(TuMV)is a devastating potyvirus pathogen that infects a wide variety of both cultivated and wild Brassicaceae plants.We urgently need more information and understanding of TuMV pathogenesis and the host responses involved in disease development in cruciferous crops.TuMV displays great versatility in viral pathogenesis,especially in its replication and intercellular movement.Moreover,in the coevolutionary arms races between TuMV and its hosts,the virus has evolved to co-opt host factors to facilitate its infection and counter host defense responses.This review mainly focuses on recent advances in understanding the viral factors that contribute to the TuMV infection cycle and the host resistance mechanism in Brassica.Finally,we propose some future research directions on TuMV pathogenesis and control strategies to design durable TuMV-resistant Brassica crops.

Clinical manifestations and the prenatal diagnosis of trisomy 7 mosaicism:Two case reports

BACKGROUND The clinical manifestations of trisomy 7 mosaicism are diverse and nonspecific,so prenatal diagnosis is very difficult.CASE SUMMARY Two pregnant women with abnormal prenatal screening results were included.One was a 22-year-old woman(G1P0).At 31st week of gestation,ultrasound revealed that the posterior horn of the left lateral ventricle was 10 mm and the right renal pelvis had a separation of 7 mm.The other pregnant woman was 33 years old(G2P1L1A0),and her fetus was found to have a cardiac malformation at the 24th week of gestation.Copy number variation sequencing,whole-exome sequencing and karyotype analysis were carried out after amniocentesis,and both fetuses were diagnosed with trisomy 7 mosaicism.After parental counseling,one woman continued the pregnancy,and the other woman terminated the pregnancy.CONCLUSION In trisomy 7 mosaicism,the low proportion of trisomy does not lead to abortion,but can result in abnormal fetal development,which can be detected via ultrasound.Therefore,clinicians need to pay more attention to various aspects of fetal growth and development,combining with imaging,cellular,molecular genetics and other methods to perform comprehensive evaluations of fetuses to provide more reliable genetic counseling for pregnant women.

Floristic Diversity, Stand Structure and Plant Life Traits in the Forest-Savanna Mosaic at Ndjole (Centre Cameroon)

With the aim of assessing floristic diversity, stand structure and vegetation ecology, the present work was carried out in the savanna mosaic forest of the locality of Ndjole (Centre Cameroon). A total of 30 floristic plots of 40 m × 40 m (1600 m2) were delineated in the different ecosystems (forest, forest-savanna contact zone and the savanna). Within each plot, all individuals with a diameter at breast height ≥ 10 cm at 1.30 m were taken into account. ANOVA was used to compare the means of the diversity indices of the different ecosystems, and the DUNCAN test at 5% significance level (XLSTAT 2016) to separate these means. A total of 85 species belonging to 67 genera and 33 families were recorded. That is, 68 species in semi-caducifolia forest, 45 in forest-savanna contact zone and 18 in savanna. Urticaceae, Combretaceae, Apocynaceae, Myristicaceae and Euphorbiaceae are the most diverse families in the forest. On the other hand, in contact zones, the Euphorbiaceae, Fabaceae, Annonaceae and Moraceae families are the most diversified, while in the savannas, the Combretaceae, Fabaceae and Annonaceae families are the most diversified. Shannon’s diversity index values (1.7 to 2.37 bits) reflect low specific diversity;Piélou’s equitability (0.86 to 0.9) shows good distribution of individuals within species. The diametric structure of woody species shows an inverted “J” shape in all plant communities. This indicates a high regeneration potential characterized by a greater number of small trees than large trees. Mesophanerophytes and megaphanerophytes are dominant in forests and forest-savanna contact zones, and microphanerophytes in the savannas. Endozoochory is the main mode of diaspore dissemination. As regards the distribution of phytogeographical types, it shows the overall dominance of Guineo-Congolese species in all plant communities. Our study provides detailed data on forest-savanna floristic and plant life traits in the mosaic and recommends further studies on the impact of environmental parameter variations on the forest encroachment into savanna.

Reactions of Maruca Resistant Transgenic Cowpea to Cowpea Aphid-Borne Mosaic Virus

Cowpea (Vigna unguiculata L. [Walp.]) in one of the main grain legumes contributing to food security and poverty alleviation in Sub-Saharan Africa. To control the highly damaging legume pod borer Maruca vitrata F., transgenic cowpea lines expressing the insecticidal Cry1Ab Bt protein were developed. In this study, we evaluated the impact of Cry1Ab transgene expression on the susceptibility of four cowpea lines (named IT97K-T, IT98K-T, Gourgou-T and Nafi-T) and their respective non-transgenic near isogenic lines (IT97K, IT98K, Gourgou and Nafi) to Cowpea aphid-borne mosaic virus (CABMV) in greenhouse conditions. In a preliminary quality control test by enzyme-linked immunosorbent assay, the presence of Cry1Ab protein in transgenic seed lots ranged from 59% to 72%, with no significant differences among the lines (χ2 = 3.26;p = 0.35). Upon virus inoculation, all cowpea lines exhibited mosaic symptoms with similar severity between 7- and 11-day post-inoculation. No significant differences were observed in symptom severity. Significant differences were found between cowpea lines for time of symptom onset, virus accumulation in plants and days to 50% flowering. However, while comparing pairs of transgenic lines and corresponding non-transgenic lines, virus accumulation showed not significant differences whatever the pair. Time of symptom onset and days to 50% flowering did not also differ significantly between pairs of cowpea lines except Nafi/Nafi-T in which transgenic Nafi-T showed earlier symptoms (7.4 ± 0.7 vs. 8.9 ± 0.8 days post-inoculation) and shorter flowering time (37.3 ± 0.6 vs. 42 ± 1.7 days after sowing). Overall, these findings improve our understanding of the effects of Cry1Ab gene mediated genetic modification on cowpea infection by Cowpea aphid-borne mosaic virus, with potential implications for environmental safety assessment.

General mapping of one-dimensional non-Hermitian mosaic models to non-mosaic counterparts:Mobility edges and Lyapunov exponents

We establish a general mapping from one-dimensional non-Hermitian mosaic models to their non-mosaic counterparts.This mapping can give rise to mobility edges and even Lyapunov exponents in the mosaic models if critical points of localization or Lyapunov exponents of localized states in the corresponding non-mosaic models have already been analytically solved.To demonstrate the validity of this mapping,we apply it to two non-Hermitian localization models:an Aubry-Andre-like model with nonreciprocal hopping and complex quasiperiodic potentials,and the Ganeshan-Pixley-Das Sarma model with nonreciprocal hopping.We successfully obtain the mobility edges and Lyapunov exponents in their mosaic models.This general mapping may catalyze further studies on mobility edges,Lyapunov exponents,and other significant quantities pertaining to localization in non-Hermitian mosaic models.

GmTOC1b negatively regulates resistance to Soybean mosaic virus

Soybean(Glycine max)is a major oil and feed crop worldwide.Soybean mosaic virus(SMV)is a globally occurring disease that severely reduces the yield and quality of soybean.Here,we characterized the role of the clock gene TIMING OF CAB EXPRESSION 1b(GmTOC1b)in the resistance of soybean to SMV.Homozygous Gmtoc1b mutants exhibited increased tolerance to SMV strain SC3 due to the activation of programmed cell death triggered by a hypersensitive response.Transcriptome deep sequencing and RT-qPCR analysis suggested that GmTOC1b likely regulates the expression of target genes involved in the salicylic acid(SA)signaling pathway.GmTOC1b binds to the promoter of GmWRKY40,which encodes a protein that activates the expression of SA-mediated defense-related genes.Moreover,we revealed that the GmTOC1bH1 haplotype,which confers increased tolerance to SMV,was artificially selected in improved cultivars from the Northern and Huang-Huai regions of China.Our results therefore identify a previously unknown SMV resistance component that could be deployed in the molecular breeding of soybean to enhance SMV resistance.

An image mosaic technique with non-overlapping regions based on microscopic vision in precision assembly

Microscopic vision has been widely applied in precision assembly.To achieve sufficiently high resolution in measurements for precision assembly when the sizes of the parts involved exceed the field of view of the vision system,an image mosaic technique must be used.In this paper,a method for constructing an image mosaic with non-overlapping areas with enhanced efficiency is proposed.First,an image mosaic model for the part is created using a geometric model of the measurement system installed on a X-Y-Z precision stages with high repeatability,and a path for image acquisition is established.Second,images are captured along the same path for a specified calibration plate,and an entire image is formed based on the given model.The measurement results obtained from the specified calibration plate are utilized to identify mosaic errors and apply compensation for the part requiring measurement.Experimental results show that the maximum error is less than 4μm for a camera with pixel equivalent 2.46μm,thereby demonstrating the accuracy of the proposed method.This image mosaic technique with non-overlapping regions can simplify image acquisition and reduce the workload involved in constructing an image mosaic.

The Clinical Outcomes of Mosaic Embryo Transfer in Preimplantation Genetic Testing Cycles

Purpose: We aimed to analyze the pregnancy outcomes and perinatal follow-up of mosaic embryo transfer in the preimplantation genetic testing (PGT) cycles. Method: We retrospectively selected 27 mosaic embryo transfer cycles as the study group and 97 euploid embryo transfer cycles as the control group after propensity score matching, which were performed in the reproductive medicine center of the Sixth Affiliated Hospital, Sun Yat-sen University, from March 2019 to September 2023. The biopsy cells from blastocyst were undertaken next generation sequencing (NGS). Results: No significant difference in pregnancy outcomes compared between the two groups. According to the size of aneuploid, fragment the level of mosaicism or blastocyst morphological gradings, there were no significant difference in mosaic embryo transfers. Conclusion: Mosaic embryo detected in the PGT cycle can lead to clinical pregnancy and live birth of healthy offspring, which can be considerate suitable for transfer.

Mosaicism of a novel variant in the ANKRD11 gene in a child with a mild KBG phenotype:A case report

BACKGROUND KBG syndrome is likely underdiagnosed because of mild and non-specific features in some affected patients especially before the upper permanent central incisors eruption at about the age of 7-8 years.Somatic mosaicisms are usually recognized in the parents only after a typically affected son is diagnosed with KBG syndrome.We describe for the first time the mosaicism of a novel variant in a child with a mild KBG phenotype.CASE SUMMARY Our patient presented at 24 mo of age with short stature,hand abnormalities,facial dysmorphism and mild developmental delay.Pituitary hypoplasia and central hypothyroidism were also detected.By next generation sequencing(NGS)analysis we found a novel deletion in the ANKRD11 gene(c.4880_4893del.),that can be classified as likely pathogenic for the syndrome,with the percentage of mutated allele of 36%.We considered this finding as causative of the mild and non-specific phenotype for KBG syndrome in our patient,as previously reported in adults.A heterozygous variant in HESX1 gene,classified as variant of uncertain significance,but suspected of causing pituitary hypoplasia and hormonal deficiency,was also found.The patient started levothyroxine and growth hormone treatment.CONCLUSION The increased use of NGS analysis may expand the phenotypic spectrum of KBG syndrome because it allows genetic diagnosis of somatic mosaicisms also in children.

基于敏捷卫星平台的星载SAR Mosaic模式研究

Mosaic模式是聚束和ScanSAR的混合模式,能同时实现高分辨率、大场景成像。提出了一种易实现的Mosaic模式,它的距离向波束切换通过电扫描完成,方位向波束扫描通过机械扫描实现。敏捷卫星能通过控制俯仰机动,方便地实现方位向机械扫描,适于实施这种Mosaic模式。针对这种Mosaic模式的特点,提出了一种新的系统设计方法。该方法从零斜视角位置开始,递推求解一系列关于Burst斜视角和驻留时间的非线性方程组,得到系统参数和时间分配方案。此外,还提出了一种基于等效展宽天线方向图的Mosaic模式性能参数近似计算方法,它能直观、便利地得到Mosaic模式各种性能参数。

Virus Movement Protein Gene Mediated Resistance Against Cucumber Mosaic Virus Infection

Tobacco ( Nicotiana tabacum L.) “NC89” plants were transformed with deletion mutant of cucumber mosaic virus (CMV) movement protein (MP) gene and full_length CMV MP gene, respectively. The transformed plants were analyzed with polymerase chain reaction (PCR), PCR_Southern, Southern and Western blots. R 0 generation of the transgenic plants were inoculated with CMV. Five out of 10 lines of tobacco plants (BMPK) transformed with CMV MP deletion mutant gene showed high resistance to CMV infection and remained symptomless for up to 50 days post_inoculation. In contrast, tobacco plants (BMPR) transformed with full_length CMV MP gene did not show resistance to CMV infection. However, most of the infected full_length CMV MP gene transgenic plants recovered by showing none or very mild mosaic symptoms in 40 days post_inoculation. The results of R 1 generation of the BMPK transgenic plants tested under field conditions showed that all 5 lines of transgenic plants could delay the virus disease development.

Molecular Tagging of a New Resistance Gene to Maize Dwarf Mosaic Virus Using Microsatellite Markers

With joint analysis based on the parents, F 1, F 2 and backcrosses, the authors found that the resistance of the maize inbred line Huangzaosi to the maize dwarf mosaic virus strain B was conditioned by a major gene and polygene, and identified a new major gene. Bulked segregate and microsatellite analysis of a F 2 progeny from the combination of Huangzaosi×Mo17 were used to identify the resistance gene, mdm1(t), on the long arm of chromosome 6. This new resistance gene is tightly linked to and located between the microsatellite markers loci, phi077 and bnlg391. The linkage distances between phi077-mdm1(t) and mdm1(t)-bnlg391 are 4.74 centiMorgan (cM) and 6.72 cM respectively.

Agroinoculation as a Simple Way to Deliver a Tobacco Mosaic Virus- Based Expression Vector

烟草花叶病毒(TMV)表达载体30B是一个目前广泛应用的植物病毒表达载体,但用其生产外源蛋白时,必须先将它体外转录成RNA,才能被用来接种宿主植物。由于RNA体外转录费用昂贵、操作复杂,因此限制了30B表达载体的进一步应用。针对这一不足,我们用农杆菌接种法(agroinoculation)接种该病毒载体,即将30B cDNA置于花椰菜花叶病毒(CaMV)的35S启动子和终止子之间,再将整个表达框架插入到农杆菌T-DNA的左边界和右边界之内,构建成质粒p35S-30B,将转入该质粒的农杆菌注射到植物的叶片中,30B cDNA随T-DNA进入植物细胞后,被转录成可自我复制的RNA形式,进而发生系统侵染。为了检测此接种方式的可行性,绿色荧光蛋白(GFP)报告基因被克隆到p35S-30B中,构建成p35S-30B∶∶GFP,用含有该质粒的农杆菌进行注射操作。证实该病毒载体可通过简便的农杆菌接种法侵染Nicotiana benthamiana,在被接种植物的系统叶中,GFP的表达量可占植物总可溶蛋白的5.2％。

Mosaic方法在非均匀下垫面上的适用性研究

在非均匀下垫面情况下,Mosaic方法是目前国际上广泛运用于模式中计算地表通量的方法。大量的研究表明,下垫面的非均匀分布会引发局地环流,非均匀分布的空间尺度较大时,所引起的环流甚至可以达到海陆风的强度。这种环流的存在直接影响到次网格地表通量的计算。次网格地表非均匀分布,尤其是大尺度模式中的次网格非均匀分布,必将影响地表通量的计算。本文针对次网格地表非均匀问题,设计了高分辨率的Mosaic试验和非均匀试验,开展了不同背景风情况下的一系列数值试验,以探讨这种影响的程度。结果表明,在土壤湿度空间分布不均匀的情况下,运用Mosaic方法计算得到的地表潜热通量偏小,背景风较小的时候偏差较大,背景风增强时偏差减小。

基于改进Mosaic数据增强和特征融合的Logo检测

近年来,Logo检测在知识产权保护和产品品牌管理等领域得到了广泛应用;针对Logo检测中的复杂背景和多尺度问题,提出了一种改进Mosaic数据增强和特征融合的Logo检测算法;将6张原始图片随机翻转、缩放和拼接构成合成图像,与单张图像和由4张原始图片合成的图像一起作为YOLOv4模型的训练输入,并确定3种输入形式的最优比例,同时使用一种新的训练策略,改进的Mosaic数据增强方法丰富了Logo对象的尺度和背景,使模型更好地学习全局和局部特征;在路径整合网络(PANet)的基础上引入跨层连接、重复堆叠、直接连接和加权特征融合等操作,改进的PANet扩大了模型感受野,增强了模型的多尺度特征表达能力;实验结果表明,提出的MP-YOLOv4算法在减小21.7%模型大小的同时,IoU(intersection of union)等于0.5时的平均精度上达到了67.4%,较YOLOv4提高了2.4%,同时在多尺度目标上的检测性能得到了改善。

Molecular Characterization of a Chinese Soybean Mosaic Virus Isolate by RT_PCR, cDNA Sequence Analysis and Direct Expression of PCR Products in Bacteria

Soybean mosaic virus (SMV) causes one of the most severe viral diseases in soybean ( Glycine max L.) and is known to contain many pathogenically and serologically related isolates. In the present study, the authors have obtained cDNAs to all cistrons of a Chinese SMV isolate, SMV_ZK, by RT_PCR. By analysing the nucleotide and amino acid sequence of the HC_PRO, NIb and CP cistrons, it was found that SMV_ZK was highly homologous to the G2 strain of SMV, thus confirming the existence of G2_like isolates in soybean crop in China. The amplified cDNAs were directly cloned into a bacterial expression vector. With the exception of the P3 cistron, expression of the cDNAs of all other cistrons in bacteria gave rise to polypeptides of expected molecular weight. The expressed viral proteins were subsequently purified by gel elution. The preparation of viral_specific cDNAs and gene products will be useful in future functional study of the SMV genome.