RESUMO
The absence of real-time airspeed sensors, which was more often ignored in previous studies, and low dynamic characteristics render stratospheric airship control challenging. This study creatively overcomes the aforementioned problems in an integrated path planning and following control scheme using forecasted wind field data. Herein, an efficient and practicable path planning algorithm is designed. Further, a smooth vector field guidance law is proposed for solving the problem of complex path following. Subsequently, an event-triggered neural network-based adaptive tracking controller is designed, considering the wind forecast error influence. Finally, these three parts are organically integrated to achieve autonomous flight. The stability of the closed-loop system and the exclusion of Zeno behavior are rigorously proved. The simulation results reveal that the convergence rate is 63.8% improved, essentially exhibiting better optimization, the tracking errors are eliminated within 80 s, and 99.4% control input updating times are saved.
RESUMO
Subcellular mRNA localization is an evolutionarily conserved mechanism to spatially and temporally drive local translation and, in turn, protein targeting. Hence, this mechanism achieves precise control of gene expression and establishes functional and structural networks during cell growth and development as well as during stimuli response. Since its discovery in ascidian eggs, mRNA localization has been extensively studied in animal and yeast cells. Although our knowledge of subcellular mRNA localization in plant cells lags considerably behind other biological systems, mRNA localization to the endoplasmic reticulum (ER) has also been well established since its discovery in cereal endosperm cells in the early 1990s. Storage protein mRNA targeting to distinct subdomains of the ER determines efficient accumulation of the corresponding proteins in different endosomal storage sites and, in turn, underlies storage organelle biogenesis in cereal grains. The targeting process requires the presence of RNA localization elements, also called zipcodes, and specific RNA-binding proteins that recognize and bind these zipcodes and recruit other factors to mediate active transport. Here, we review the current knowledge of the mechanisms and functions of mRNA localization to the ER in plant cells and address directions for future research.
Assuntos
Endosperma , Células Vegetais , Animais , Endosperma/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Células Vegetais/metabolismo , Retículo Endoplasmático/metabolismo , Transporte Proteico , Grão Comestível/metabolismoRESUMO
Objective:To investigate the characteristics of habitual sleeping position and triggered movement in patients with benign paroxysmal positional vertigoï¼BPPVï¼. Methods:The patients with idiopathic tubulitic BPPV who the symptoms were relieved after repositioning were enrolled in this study. The relationship between the side, the tube of otolith detachment and habitual sleeping position and triggered movement was analyzed. Results:â Among the 446 patients, female gender predominatedï¼319 cases, 71.5%ï¼, 41-60 years old group accounted for the highest proportionï¼192 cases, 43.0%ï¼, and posterior semicircular canal patients accounted for the highest proportionï¼289 cases, 64.8%ï¼; â¡The affected side was associated with habitual sleep postionï¼P<0.05, ES=0.392ï¼, ipsilateral ear was more common in left or right decubitus; â¢There were statistically significant differences in the triggered movement in different types of BPPVï¼P<0.05, ES=0.380ï¼, BPPV of multiple semicircular canals. Horizontal semicircular canals and posterior semicircular canals were more likely to induce vertigo and nystagmus. Conclusion:Habitual sleeping position and triggered movement could be collected during the diagnosis of BPPV, to predict the affected side and tube. The combination of Roll test and Dix-Hallpike test is more conducive to accurately distinguish the location of otolith shedding.