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.

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.

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.

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.

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.

Frequency-Hopping Frequency Reconnaissance and Prediction for Non-cooperative Communication Network

The continuous change of communica-tion frequency brings difficulties to the reconnaissance and prediction of non-cooperative communication net-works.Since the frequency-hopping(FH)sequence is usually generated by a certain model with certain regularity,the FH frequency is thus predictable.In this paper,we investigate the FH frequency reconnais-sance and prediction of a non-cooperative communi-cation network by effective FH signal detection,time-frequency(TF)analysis,wavelet detection and fre-quency estimation.With the intercepted massive FH signal data,long short-term memory(LSTM)neural network model is constructed for FH frequency pre-diction.Simulation results show that our parameter es-timation methods could estimate frequency accurately in the presence of certain noise.Moreover,the LSTM-based scheme can effectively predict FH frequency and frequency interval.

Low sidelobe robust imaging in random frequency-hopping wideband radar based on compressed sensing

High resolution range imaging with correlation processing suffers from high sidelobe pedestal in random frequency-hopping wideband radar. After the factors which affect the sidelobe pedestal being analyzed, a compressed sensing based algorithm for high resolution range imaging and a new minimized ll-norm criterion for motion compensation are proposed. The random hopping of the transmitted carrier frequency is converted to restricted isometry property of the observing matrix. Then practical problems of imaging model solution and signal parameter design are resolved. Due to the particularity of the proposed algorithm, two new indicators of range profile, i.e., average signal to sidelobe ratio and local similarity, are defined. The chamber measured data are adopted to testify the validity of the proposed algorithm, and simulations are performed to analyze the precision of velocity measurement as well as the performance of motion compensation. The simulation results show that the proposed algorithm has such advantages as high precision velocity measurement, low sidelobe and short period imaging, which ensure robust imaging for moving targets when signal-to-noise ratio is above 10 dB.

A NEW METHOD OF FREQUENCY-HOPPING(FH) SIGNAL DETECTION

A new Frequency-Hopping(FH) signal detection method is proposed.Different from pre-vious methods which need to monitor the total band,it can monitor part of the band and decrease the range of the bandwidth.According to this method,a new detection model is set and the computation formulas of the detection probability and false-alarm probability are given.The parameters of a VHF radio are used to prove the validity of the method.Simulation results show that this method can de-crease the range of the bandwidth and detect the FH signal with some penalty on the SNR and signal loss.

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.

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.

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.

淮北石台煤矿接触变质煤速热碳化的微组构解译

作为岩浆吞噬煤层的信息记录者和物质承载者,接触变质煤是揭示煤层速热碳化过程和机理的重要研究对象。为此,本研究采集了淮北石台煤矿不同热变质程度的接触变质煤样品,利用镜质组反射率测试、元素分析、工业分析、偏光显微镜(PLM)和扫描电镜(SEM)等实验手段,表征其微组构特征,以期揭示煤层速热碳化的机理和过程。结果显示,从未受影响煤、浅热变质煤到天然焦,样品最大镜质组反射率、灰分产率升高,氢、氮元素以及挥发分含量降低。未受影响煤显微组分以胶质结构体为主,局部发育丝质体;浅热变质煤中裂隙发育、少见脱挥发孔;靠近岩体的块状天然焦中镶嵌结构炭和脱挥发孔发育,孔径多介于20~150μm;岩体内的细脉状天然焦,主要由多孔炭和炭微球组成,富含圆形—椭圆形气孔,孔径多介于1~3μm。分析表明,趋近岩体,接触变质煤热变质程度连续增加:浅热变质煤是煤层受较弱热变质而脆性断裂的结果;天然焦是浅热变质煤热解脱挥发分和中间相化的产物;至岩体附近,天然焦被液化成多孔炭和炭微球,后二者最终被氧化为气态碳氧化物而消失。我们认为,岩浆接触变质煤速热碳化的实质就是固态煤岩被岩浆热解而中间相化、液化和氧化气化的过程。

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“马赛克战”的水下有人-无人作战使用探讨

通过对“马赛克战”概念的背景和特点进行分析,提出基于马赛克的水下攻防作战运用构想,构建基于马赛克的水下有人-无人作战网络,分析多域背景下水下OODA作战网络的构成,利用OODA作战环理论对水下马赛克作战网络作战能力进行分析,并提出水下马赛克作战网络对抗单个平台和对抗作战网络的使用方法。最后,从通信组网、集群使用、人工智能、察打一体等4个方面对“马赛克战”概念下水下无人航行器装备使用提出建议。

基于小RNA深度测序和RT-PCR鉴定鹅绒藤花叶病的病毒病原

鹅绒藤(Cynanchum chinense)是一种传统中药,为明确造成鹅绒藤叶片花叶症状的原因,本研究采用小RNA深度测序技术结合RT-PCR的方法鉴定引起山西太谷鹅绒藤病毒花叶症状的病原,并通过生物信息学的手段对病毒序列进行分析。结果表明,发病鹅绒藤样品经小RNA深度测序技术共获得15039334个原始序列,将拼接contigs与NCBI中的病毒数据库进行比对注释,结果显示病原为苜蓿花叶病毒(AMV)和黄瓜花叶病毒(CMV)。利用特异引物克隆了AMV和CMV的外壳蛋白(CP)和移动蛋白(MP)基因全序列,分别命名为AMV-BR和CMV-BR。通过序列比对分析,发现AMV-BR CP氨基酸序列和核苷酸序列与AMV分离物AMV-Gyn(MH332899)、Dich-rep(MW835989)和VIC-320(MF075254)的相似性均达到100%;MP氨基酸序列和核苷酸序列与AMV分离物AMV-Gyn(MH332899)的相似性最高,均为99.3%。CMV-BR CP氨基酸序列和核苷酸序列与CMV亚组ⅠA中CMV分离物YA17(MH119159)的相似性最高,分别为100%和99.1%;MP氨基酸序列和核苷酸序列与CMV亚组Ⅰ分离物PV-0185(ON013887)的相似性最高,分别为98.2%和96.4%。MP和CP氨基酸序列系统进化分析表明,CMV-BR属于CMV亚组Ⅰ中的成员。这是首次在山西鹅绒藤上检测到AMV和CMV,该研究有助于深入了解AMV、CMV的分子进化,也为鹅绒藤病毒病的防治提供一定的理论依据。

ToMMV病残体中病毒存活力及其传病作用

因番茄斑驳花叶病毒(ToMMV)寄主范围广,传染性和致病力强,以ToMMV为对象,对其产生的植株病残体进行了病毒分布和存活时间检测、侵染活性分析以及传毒作用测试。结果表明:烟草植株病残体的叶、茎、根中均含有病毒,ToMMV可在病残体存活较长时间,病死枯叶室温存放90 d后病毒依然存在,且仍保持侵染活性,刀片刮划枯叶模拟农事操作接毒后发现病残体具有传毒作用;ToMMV可在病残体中长时间保持侵染活力,田间病残体很可能会成为下茬作物的初侵染源;土壤无直接传毒作用,但混有病残体的土壤也可成为初侵染源,且沾染在农具表面的离体病毒依然可以在一定时间内维持侵染活力,成为潜在的初侵染源。综上,清除植株病残体(减少初侵染源)是预防和控制ToMMV传播和扩散的重要环节,生产上应给予充分重视。