QTL analysis of ear leaf traits in maize(Zea mays L.)under different planting densities

Modem maize varieties have become more productive than ever, owing largely to increased tolerance of high plant density. However, the genetics of ear leaf traits under different densities remains poorly understood. In this study, Zhongdan 909 recombinant inbred lines(RILs) derived from a cross between Z58 and HD568 were genotyped for 3072 single-nucleotide polymorphisms(SNPs), and phenotyped for leaf length(LL), leaf width(LW), and leaf angle(LA) of the uppermost ear leaf under three planting densities(52,500,67,500, and 82,500 plants ha-1, respectively). A genetic map was then constructed using1358 high-quality SNPs. The total length of the linkage map was 1985.2 cM and the average interval between adjacent markers 1.46 cM. With increasing density, LL and LW decreased from 63.68 to 63.02 cm and from 8.56 to 8.21 cm, respectively, while LA increased from19.42° to 19.66°. All three traits had high heritabilities, of 0.75, 0.78, and 0.84, respectively.Using inclusive composite interval mapping, 23, 25, and 17 quantitative trait loci(QTL) were detected for LL, LW, and LA, respectively. Of these, 35 were simultaneously detected under two or three plant densities, while 30 were detected under only one. Sixty-five individual QTL explained 2.41% to 16.53% of phenotypic variation, while eight accounted for >10%.These findings will help us understand the genetic basis of leaf traits in maize as well as the response of maize to increased plant density.

Genetic analysis and QTL mapping of stalk cell wall components and digestibility in maize recombinant inbred lines from B73 × By804

The cell wall composition and structure of the maize stalk directly affects its digestibility and in turn its feed value.Previous studies of stem quality have focused mostly on common maize germplasm,and few studies have focused on high-oil cultivars with high grain and straw quality.Investigation of the genetic basis of cell wall composition and digestibility of maize stalk using high-oil maize is desirable for improving maize forage quality.In the present study,a high-oil inbred line(By804)was crossed as male parent with the maize inbred line B73 to construct a population of 188 recombinant inbred lines(RILs).The phenotypes of six cell-wall-related traits were recorded,and QTL analysis was performed with a genetic map constructed with SNP markers.All traits were significantly correlated with one another and showed high broad-sense heritability.Of 20 QTLs mapped,the QTL associated with each trait explained 10.0%–41.1%of phenotypic variation.Approximately half of the QTL each explained over 10%of the phenotypic variation.These results provide a theoretical basis for improving maize forage quality by marker-assisted selection.

Changes of auditory evoked magnetic fields in patients after acute cerebral infarction using magnetoencephalography

Auditory evoked magnetic fields were recorded from 15 patients with acute cerebral infarction and 11 healthy volunteers using magnetoencephalography.The auditory stimuli of 2 kHz pure tone were binaurally presented with an interstimulus interval of 1 second.The intensity of stimuli was 90 dB and the stimulus duration was 8 ms.The results showed that the M100 was the prominent response, peaking approximately 100 ms after stimulus onset in all subjects.It originated from the area close to Heschl’s gyrus.In the patient group,the peak latency of M100 responses was significantly prolonged,and the mean strength of equivalent current dipole was significantly smaller in the affected hemisphere.The three-dimensional inter-hemispheric difference of the M100 positions was increased in the patient group.Our experimental findings suggested that impairment of cerebral function in patients with acute ischemic stroke can be detected using magnetoencephalography with the higher spatial resolution and temporal resolution.Magnetoencephalography could provide objective and sensitive indices to estimate auditory cortex function in patients with acute cerebral infarction.

Genome-wide alternative splicing variation and its potential contribution to maize immature-ear heterosis

Heterosis is a well-known phenomenon widely applied in agriculture.Recent studies have suggested that differential gene and protein expression between hybrids and their parents play important roles in heterosis.Alternative splicing(AS)is an essential posttranscriptional mechanism that can greatly affect the transcriptome and proteome diversity in plants.However,genome-wide AS divergence in hybrids compared to their parents and its potential contribution to heterosis have not been comprehensively investigated.We report the direct profiling of the AS landscape using RNA sequencing data from immature ears of the maize hybrid ZD808 and its parents NG5 and CL11.Our results revealed a large number of significant differential AS(DAS)events in ZD808 relative to its parents,which can be further classified into parental-dominant and novel DAS patterns.Parental-dominant,especially NG5-dominant,events were prevalent in the hybrid,accounting for 42%of all analyzed DAS events.Functional enrichment analysis revealed that the NG5-dominant AS events were involved mainly in regulating the expression of genes associated with carbon/nitrogen metabolism and cell division processes and contributed greatly to maize ear heterosis.Among ZD808,CL11,and NG5,32.5%of DAS contained or lacked binding sites of at least one annotated maize microRNA(miRNA)and may be involved in miRNA-mediated posttranscriptional regulation.Cis regulation was the predominant contributor to AS variation and participates in many important biological processes associated with immature ear development.This study provides a comprehensive view of genome-wide alternative splicing variation in a maize hybrid.

Finite-time path following control of a sailboat with actuator failure and unknown sideslip angle

Suffering from actuator failure and complex sideslip angle,the motion control of a sailboat becomes challenging.In this paper,an improved double finite-time observer-based line-of-sight guidance and finite-time control(IDFLOS-FC)scheme is presented for path following of sailboats.The salient features of the proposed IDFLOS-FC scheme are as follows:(1)Considering the problem of actuator failure,an actuator failure model is introduced into the dynamics model of a sailboat.(2)The time-varying sideslip angle of the sailboat is accurately observed by the double finite-time sideslip observers(DFSOs),which reduces the error in line-of-sight(LOS)guidance.(3)A radial basis function(RBF)neural network is used to fit the uncertainty of the model,and the upper bound of the sum of fault effects and external disturbances is estimated based on adaptive theory,so that the controller has accurate tracking and interference suppression.(4)According to the Lyapunov method,the system is finite-time stable.Finally,simulation was used to validate the effectiveness of the method.

新闻传播类博物馆发展方向管窥

本文通过对部分国家和地区新闻传播类博物馆的考察,提炼出这一类别博物馆的三种主题方向,或以媒体行业为主题、或以媒体技术为主题、或将媒体技术变革与社会发展历史进行勾连。通过梳理各地新闻传播类博物馆的不同主题的表现,审视其运营模式、展陈布置、功能性,总结可资借鉴的建设经验,为中国建设自己的新闻传播类博物馆提供参考。

Effects of water on CO catalytic oxidation over Pd/CeO2

The role of water in CO oxidation was investigated on Pd/CeO2 with different morphologies(rods(R),cubes(C)and octahedrons(O)).Compared with the absence of water,CO oxidation activity increases 2 times in the presence of water on Pd/CeO2-C;but a decrease is found on Pd/CeO2-R.Catalyst characterization reveals that Pd is mainly in the form of solid solution(PdxCe1-xO2-σ)on Pd/CeO2-R and a mixture of metal and PdxCe1-xO2-σsolid solution on Pd/CeO2-C.The strong interaction between Pd and CeO2-R results in the form of stable bidentate carbonates species;while the relatively weak interaction between Pd and CeO2-C leads to the produce of unstable monodentate carbonates species.The effects of water on CO oxidation activity closely relate with the Pd chemical state and the types of carbonates species.Water restrains CO adsorption on PdxCe1-xO2-σsolid solution,but it has negligent effects on metallic Pd species.In the presence of water,bidentate carbonates species remains stable but the decrease in the amount of monodentate carbonates species is observed.

未成年犯管教所的转型与发展

随着未成年犯减少,未成年犯管教所何去何从需要思考。未成年犯减少了,但并不意味青少年犯罪就没有了。结合实际,未成年犯管教所转型应向国家现代化综合治理方向前进。建议在保持全国未成年犯管教所建制和模式下,打造青少年法治教育综合体,让问题学生来接受警示教育,家长学习管教子女的经验,从而实现为社会服务的功能。