Further results on laws of large numbers for uncertain random variables

summary:The uncertainty theory was founded by Baoding Liu to characterize uncertainty information represented by humans. Basing on uncertainty theory, Yuhan Liu created chance theory to describe the complex phenomenon, in which human uncertainty and random phenomenon coexist. In this paper, our aim is to derive some laws of large numbers (LLNs) for uncertain random variables. The first theorem proved the Etemadi type LLN for uncertain random variables being functions of pairwise independent and identically distributed random variables and uncertain variables without satisfying the conditions of regular, independent and identically distributed (IID). Two kinds of Marcinkiewicz-Zygmund type LLNs for uncertain random variables were established in the case of $p \in (0, 1)$ by the second theorem, and in the case of $p > 1$ by the third theorem, respectively. For better illustrating of LLNs for uncertain random variables, some examples were stated and explained. Compared with the existed theorems of LLNs for uncertain random variables, our theorems are the generalised results

Piezo1 integration of vascular architecture with physiological force

The mechanisms by which physical forces regulate endothelial cells to determine the complexities of vascular structure and function are enigmatic¹⁻⁵. Studies of sensory neurons have suggested Piezo proteins as subunits of Ca²⁺-permeable non-selective cationic channels for detection of noxious mechanical impact⁶⁻⁸. Here we show Piezo1 (Fam38a) channels as sensors of frictional force (shear stress) and determinants of vascular structure in both development and adult physiology. Global or endothelial-specific disruption of mouse Piezo1 profoundly disturbed the developing vasculature and was embryonic lethal within days of the heart beating. Haploinsufficiency was not lethal but endothelial abnormality was detected in mature vessels. The importance of Piezo1 channels as sensors of blood flow was shown by Piezo1 dependence of shear-stress-evoked ionic current and calcium influx in endothelial cells and the ability of exogenous Piezo1 to confer sensitivity to shear stress on otherwise resistant cells. Downstream of this calcium influx there was protease activation and spatial reorganization of endothelial cells to the polarity of the applied force. The data suggest that Piezo1 channels function as pivotal integrators in vascular biology

Dynamics Modeling and Simulation of a Net Closing Mechanism for Tether-Net Capture

Tether-net is a promising active debris removal technique, and a closing mechanism can ensure the reliable wrapping of space debris by using tether-net. This study focuses on the dynamics model of the split closing mechanism and the sliding joint between thread and ring. First, a new kind of closing mechanism is proposed, which drives the closing thread to close the net mouth through the split masses, and the mass-spring-damper method is used to model tether-net. Thereafter, for the first time, the model of thread-ring sliding joint is proposed based on the mass-spring-damper method, which can be used to simulate the closing process of tether-net. Finally, one-edge closure experiment of the net is carried out and the experimental results are compared with the simulation results, and the closing process of the tether-net is simulated by using the thread-ring sliding joint. Results reveal that the thread-ring sliding joint can be used to simulate the relative slip between the thread and the ring, and the tether-net can wrap the target reliably in a short time by using the split closing system. The split closing mechanism can make it possible for the tether-net to close successfully, whether it starts to work before or after the net contacts with the target

Polarized Coulomb field scattering in LaAlO3/SrTiO3 heterojunction field-effect transistors

LaAlO3/SrTiO3 heterojunction field-effect transistors (HFETs) were fabricated. Using a combination of measured current–voltage (I–V) output curves and gate-source capacitance–voltage (C–V) characteristic curves for the fabricated LaAlO3/SrTiO3 HFETs, and considering scattering mechanisms for longitudinal optical phonon, interface rough, electron-electron (E-E), acoustic phonon, and polarized Coulomb field (PCF), the channel electron mobility of LaAlO3/SrTiO3 HFETs has been calculated and analyzed. The results showed that PCF scattering is a significant carrier scattering mechanism in LaAlO3/SrTiO3 HFETs. The heterostructure of the LaAlO3/SrTiO3 system has strong polarization characteristics. This paper is the first to demonstrate that PCF scattering is a significant carrier scattering mechanism in LaAlO3/SrTiO3 HFETs, following GaN HFETs, thus demonstrating that LaAlO3/SrTiO3 HFETs also have PCF scattering effect

Biochemical Comparison of dsRNA Degrading Nucleases in Four Different Insects

Double stranded RNAs (dsRNA) degrading nuclease is responsible for the rapid degradation of dsRNA molecules, and thus accounts for variations in RNA interference (RNAi) efficacy among insect species. Here, the biochemical properties and tissue-specific activities of dsRNA degrading nucleases in four insects (Spodoptera litura, Locusta migratoria, Periplaneta americana, and Zophobas atratus) from different orders were characterized using a modified assay method. The results revealed that all insect dsRNA degrading nucleases tested showed high activity in alkaline environments at optimal Mg2+ concentrations and elevated temperatures. We also found that enzymes from different insects varied in terms of their optimal reaction conditions and kinetic parameters. Whole body enzyme activity differed dramatically between insect species, although enzymes with higher substrate affinities (lower Km) were usually balanced by a smaller Vmax to maintain a proper level of degradative capacity. Furthermore, enzyme activities varied significantly between the four tested tissues (whole body, gut, hemolymph, and carcass) of the insect species. All the insects tested showed several hundred-fold higher dsRNA degrading activity in their gut than in other tissues. Reaction environment analysis demonstrated that physiological conditions in the prepared gut fluid and serum of different insects were not necessarily optimal for dsRNA degrading nuclease activity. Our data describe the biochemical characteristics and tissue distributions of dsRNA degrading activities in various insects, not only explaining why oral delivery of dsRNA often produces lower RNAi effects than injection of dsRNA, but also suggesting that dsRNA-degrading activities are regulated by physiological conditions. These results allow for a better understanding of the properties of dsRNA degrading nucleases, and will aid in the development of successful RNAi strategies in insects

A Mathematical Model of the Hydrodynamic Pressure Acting on a Turbine Runner Blade under the Rotor-Stator Interaction Based on the Quasi-Three-Dimensional Finite Element Method

In this paper, a turbine runner blade under hydraulic excitation was taken as the object of study and the mathematical hydrodynamic pressure model of a turbine runner blade under the rotor-stator interaction was established using quasi-three-dimensional finite element model. The regularity of the distribution of the hydrodynamic pressure was then investigated. First, the quasi-three-dimensional finite element model of a runner blade was established using the quasi-three-dimensional theory. Next, according to the pressure distribution from the numerical simulation, the mathematical mean pressure model of a node was established using the relative pressure difference method; the pressure fluctuation was then established taking the rotor-stator interaction into consideration. Then, based on the mean pressure and the pressure fluctuation of a node, the mathematical hydrodynamic pressure model for any position of a runner blade was obtained. Finally, the feasibility of the mathematical model was verified by an example analysis, and the internal relationship between the hydrodynamic pressure and its hydraulic parameters and the structural parameters of the blade was revealed, which provides a theoretical basis for further study of the dynamic characteristics of turbine runner blades under the rotor-stator interaction

Mode specificity of the dissociative chemisorption of HOD on rigid Cu(111): an approximate full-dimensional quantum dynamics study

The validity of the site averaging approximation with exact potential (SAEP) has been confirmed in a recent work on the H2O/Cu(111) system [Z. Zhang, T. Liu, B. Fu, X. Yang, D. H. Zhang, Nat. Commun. 2016, 7, 11953]. Here, the mode specificity of the dissociative chemisorption of HOD on a rigid Cu(111) surface is investigated by carrying out the seven-dimensional (7D) quantum dynamics calculations on an accurate nine-dimensional (9D) potential energy surface together with the implementation of the SAEP. The approximate 9D dissociation probabilities for HOD initially in various vibrational states are obtained by averaging the site-specific 7D results over 9 impact sites. A strong bond-selective effect for the title reaction is observed, where vibrational excitation of a particular bond leads to a large enhancement only in the reaction in which the excited bond is broken. The product branching ratios strongly depend on which bond is excited, and the product from the cleavage of the excited bond is much more favored than the other product. The implementation of the SAEP allows us to investigate the mode-specific dynamics at a level of accuracy that can only be achieved in full-dimensional quantum dynamics calculations