507 research outputs found
Turning Unstructured and Incoherent Group Discussion into DATree: A TBL Coherence Analysis Approach
Despite the rapid growth of user-generated unstructured text from online group discussions, business decision-makers are facing the challenge of understanding its highly incoherent content. Coherence analysis attempts to reconstruct the order of discussion messages. However, existing methods only focus on system and cohesion features. While they work with asynchronous discussions, they fail with synchronous discussions because these features rarely appear. We believe that discussion logic features play an important role in coherence analysis. Therefore, we propose a TCA method for coherence analysis, which is composed of a novel message similarity measure algorithm, a subtopic segmentation algorithm and a TBL-based classification algorithm. System, cohesion and discussion logic features are all incorporated into our TCA method. Results from experiments showed that the TCA method achieved significantly better performance than existing methods. Furthermore, we illustrate that the DATree generated by the TCA method can enhance decision-makersâ content analysis capability
Effect of 1-MCP on storage quality and the mechanism involved in ethylene signal transduction in a new early-maturing apple variety âTaihangzaohongâ fruits during cold storage
1-Methylcyclopropene (1-MCP) can reduce the rate of fruit softening and prolong storage time. In this study, the fruit of a new early-maturing apple variety, âTaihangzaohongâ, was treated with air (control), 2 ÎŒL/L 1-MCP, 100 ÎŒL/L ethylene (C 2H4) or 2 ÎŒL/L 1-MCP +100 ÎŒL/L C2H4 for 24 hours and then stored at 4 °C for 70 days. The postharvest physiological indices and the expression of 13 genes related to ethylene biosynthesis and signal transduction were monitored every 10 days. The results showed that 1-MCP can delay the softening rate and maintain the fruit quality of this early-maturing apple variety by reducing ethylene production by reducing the expression of MdACO1, MdACO2, and MdACS1, as well as by preventing ethylene signal transduction by decreasing the expression of MdETR2 and MdERS1 and increasing the expression of MdCTR1. Understanding the significant changes in these genes and their functions may help us explore the mechanisms controlling apple fruit softening and its response to exogenous 1-MCP and ethylene stimuli, as well as inhibition at the receptor level during ripening and senescence
Characteristics of Pollen from Transgenic Lines of Apple Carrying the Exogenous CpTI Gene
AbstractIt is fundamental for gene transformation and ecosystem hazard evaluation to study the pollen characteristics of transgenic plants. In this research, the characteristics of pollen from 7- or 8-year-old transgenic apple plants carrying an exogenous CpTI gene were analyzed. The results showed that there was no significant difference in terms of size, morphology, or exine ornamentation between the pollen of the transgenic plants and the non-transgenic control. However, the transgenic plants had more abnormal pollen grains. Of the 13 transgenic lines tested, 12 had a significantly lower amount of pollen and six exhibited a significantly lower germination rate when cultured in vitro. The pollen viability of three transgenic lines was determined, with two showing significantly lower viability than the control. The transgenic Gala apple pollen grains germinated normally via controlled pollination on Fuji apple stigmas. However, the pollen tubes extended relatively slowly during the middle and late development stages, and another 8h were needed to reach the ovules compared with the control. The gibberellic acid concentration in transgenic Gala apple flowers was lower than in the non-transgenic control during all development stages tested. The abscisic acid concentration in the transgenic flowers was lower during the pink stage, and higher during the ball and fully open stages. Microscopic observation of the anther structure showed no difference. The tapetum of the pollen sac wall in transgenic plants decomposed late and affected pollen grain development, which could be one of the reasons for the lower number of pollen grains and poor viability in the transgenic plants
Classification Based on Pruning and Double Covered Rule Sets for the Internet of Things Applications
The Internet of things (IOT) is a hot issue in recent years. It accumulates large amounts of data by IOT users, which is a great challenge to mining useful knowledge from IOT. Classification is an effective strategy which can predict the need of users in IOT. However, many traditional rule-based classifiers cannot guarantee that all instances can be covered by at least two classification rules. Thus, these algorithms cannot achieve high accuracy in some datasets. In this paper, we propose a new rule-based classification, CDCR-P (Classification based on the Pruning and Double Covered Rule sets). CDCR-P can induce two different rule sets A and B. Every instance in training set can be covered by at least one rule not only in rule set A, but also in rule set B. In order to improve the quality of rule set B, we take measure to prune the length of rules in rule set B. Our experimental results indicate that, CDCR-P not only is feasible, but also it can achieve high accuracy
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A unified mechanism for intron and exon definition and back-splicing.
The molecular mechanisms of exon definition and back-splicing are fundamental unanswered questions in pre-mRNA splicing. Here we report cryo-electron microscopy structures of the yeast spliceosomal E complex assembled on introns, providing a view of the earliest event in the splicing cycle that commits pre-mRNAs to splicing. The E complex architecture suggests that the same spliceosome can assemble across an exon, and that it either remodels to span an intron for canonical linear splicing (typically on short exons) or catalyses back-splicing to generate circular RNA (on long exons). The model is supported by our experiments, which show that an E complex assembled on the middle exon of yeast EFM5 or HMRA1 can be chased into circular RNA when the exon is sufficiently long. This simple model unifies intron definition, exon definition, and back-splicing through the same spliceosome in all eukaryotes and should inspire experiments in many other systems to understand the mechanism and regulation of these processes
An Improved Grid-connected Pre-Synchronization Method based on Virtual Synchronous Generator Control in Power Conversion System
Under the background of vigorously promoting the construction of new power systemïŒthe power conversion system(PCS) plays an important role to transfer high reliable electrical power quality to grid. However, the system is sensitive to the voltage deviation on both side of point of common coupling(PCC) when switching from off-grid mode to grid-connected mode directly, it leads to surge currents or even threaten system stability.In this paper, an improved grid-connected pre-synchronization method for smooth grid connection is proposed. The system adds a pre-synchronization module on the basis of virtual synchronous generator(VSG) control to synchronize the voltage between the PCS and the grid. In addition, a slope control unit is introduced to further avoid the potential surge current problem at the moment of grid connection. Finally, the experimental results of simulation is verified the effectiveness and feasibility of the proposed scheme
Tolerance of transgenic Arabidopsis thaliana overexpressing apple MdAGO4.1 gene to drought and salt stress
The regulatory role of apple MdAGO4.1 gene in plant drought and salt resistance is unclear. In this study, transgenic A. thaliana in which the apple MdAGO4.1 gene was over-expressed was used to analyze the regulatory effects of the MdAGO4.1 gene on plant drought and salt resistance, to verify the function of the apple MdAGO4.1 gene. The seed germination rate, seedling fresh weight and root length of transgenic Arabidopsis strains in MS medium containing different concentrations of NaCl and mannitol were better than those of the wild type. The transgenic A. thaliana seedlings were more resistant to drought than wild type under drought stress. The transgenic strains were less affected by salt stress than thewild type. Exposure to drought and salt stress reduced the relative elektrolyte leakage, malondialdehyde (MDA), superoxide anion (O2-), and hydrogen peroxide (H2O2) levels of the transgenic strain significantly compared with the levels in the wild type. The levels of proline, protective enzyme activities, and the expression of genes related to drought and salt stress resistance were significantly higher than those of the wild type. These results indicate that MdAGO4.1 overexpression improved drought and salt tolerance in transgenic Arabidopsis. This study can provide a theoretical basis for future research on stress tolerance mechanisms and breeding new varieties of fruit trees resistant to drought and salt
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