谈“十四五”生态保护与绿色发展的生态关系

 从“十四五”保护与发展的生态关系角度，探讨了生态保护与绿色发展的十大生态关系，阐述了生态保护和绿色发展中的一系列有关生态关系的生态智慧及生态技术，并对长江、黄河等流域的生态保护和修复提出了相关建议。     

Simultaneous anti-windup synthesis for linear systems subject to actuator saturation

A synthesis method for global stability and performance of input constrained linear systems, which uses a linear outputfeedback controller and a static anti-windup compensator is investigated. Different from the traditional two-step anti-windup design procedure, the proposed method synthesizes all controller parameters simultaneously. Sufficient conditions for global stability and minimizing the induced L2 gain are formulated and solved as a linear matrix inequalities(LMIs) optimization problem, which also provides an opportunity to search for a better performance tradeoff between the linear controller and the anti-windup compensator.The well-posedness of the close-loop system is also guaranteed.Simulation results show the effectiveness of the proposed method.     

The influence of chronic nicotine treatment on stress-induced gastric ulceration and emptying rate in rats.

Ten-day treatment with nicotine (5, 25 or 50 micrograms/ml drinking water) dose-dependently intensified gastric ulceration induced by cold-restraint, and emptying rate. Stomach contractions produced by graded doses of bethanechol i.v. were elevated further by nicotine treatment. It is suggested that chronic nicotine administration produces hypersensitivity of the gastric muscarinic receptors; stomach hypermotility contributes to the ulcer-worsening action of the alkaloid.     

拮抗肌对的协同控制与EMG信号的中值频率关系

探讨在持续恒力收缩时,正常人体肘关节主动肌和桔抗肌的协同作用原理与它们的表面EMG信号中值频率(Median Frequency,MF)的变化趋势,研究它们的疲劳行为。十五个正常受试者的实验数据统计结果表明,拮抗肌的SEMG/MF高于主动肌;随着收缩时间的增加,主动肌和拮抗肌的MF几乎以相同的速率下降;收缩力越大,它们的两条拟合直线之间的距离、互相关系数、下降速率也越大;关节的角度的变化对上述结论似乎没有明显的影响。这些结论对屈曲和伸展模式都成立。利用人体组织的幅度衰减特性和频率衰减特性,神经肌肉系统的“共驱动”概念对上述结果进行了讨论。     

Overcompensation and population cycles in an ungulate.

Although theoretical studies show that overcompensatory density-dependent mechanisms can potentially generate regular or chaotic fluctuations in animal numbers, the majority of realistic single-species models of invertebrate populations are not overcompensatory enough to cause sustained population cycles. The possibility that overcompensation may generate cycles or chaos in vertebrate populations has seldom been considered. Here we show that highly overcompensatng density-dependent mortality can generate recurrent population crashes consistent with those observed in a naturally limited population of Soay sheep. The observed interval of three or more years between crashes points to sharp 'focusing' of mortality over a narrow range of population density.     

Retrograde transport of endocytosed Shiga toxin to the endoplasmic reticulum.

Shiga toxin and some other protein toxins that act on targets in the cytosol have previously been shown to enter the trans-Golgi network. Transport by this route may be necessary for translocation of the toxin to the cytosol and for intoxication, but it is not known whether the enzymatically active part of the toxins actually enters the cytosol from the trans-Golgi network. It has been suggested that such toxins are transported in a retrograde manner to the endoplasmic reticulum and that translocation occurs in this organelle, but retrograde transport of endocytosed material beyond the trans-Golgi network has never been demonstrated. Here we show that in butyric acid-treated A431 cells endocytosed Shiga toxin is not only transported to the trans-Golgi network, but also to all Golgi stacks, to the endoplasmic reticulum and to the nuclear envelope. Furthermore, butyric acid sensitizes the cells to Shiga toxin, which is consistent with the possibility that retrograde transport is required for translocation of the toxin to the cytosol.