A SLAM Algorithm Based on Adaptive Cubature Kalman Filter

We need to predict mathematical model of the system and a priori knowledge of the noise statistics when traditional simultaneous localization and mapping (SLAM) solutions are used. However, in many practical applications, prior statistics of the noise are unknown or time-varying, which will lead to large estimation errors or even cause divergence. In order to solve the above problem, an innovative cubature Kalman filter-based SLAM (CKF-SLAM) algorithm based on an adaptive cubature Kalman filter (ACKF) was established in this paper. The novel algorithm estimates the statistical parameters of the unknown system noise by introducing the Sage-Husa noise statistic estimator. Combining the advantages of the CKF-SLAM and the adaptive estimator, the new ACKF-SLAM algorithm can reduce the state estimated error significantly and improve the navigation accuracy of the SLAM system effectively. The performance of this new algorithm has been examined through numerical simulations in different scenarios. The results have shown that the position error can be effectively reduced with the new adaptive CKF-SLAM algorithm. Compared with other traditional SLAM methods, the accuracy of the nonlinear SLAM system is significantly improved. It verifies that the proposed ACKF-SLAM algorithm is valid and feasible

A juvenile mouse model of anti-N-methyl-D-aspartate receptor encephalitis by active immunization

IntroductionAnti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is a common autoimmune encephalitis, and it is associated with psychosis, dyskinesia, and seizures. Anti-NMDAR encephalitis (NMDARE) in juveniles and adults presents different clinical charactreistics. However, the pathogenesis of juvenile anti-NMDAR encephalitis remains unclear, partly because of a lack of suitable animal models.MethodsWe developed a model of juvenile anti-NMDAR encephalitis using active immunization with an amino terminal domain peptide from the GluN1 subunit (GluN1356 − 385) against NMDARs in 3-week-old female C57BL/6J mice.ResultsImmunofluorescence staining suggested that autoantibody levels in the hippocampus increased, and HEK-293T cells staining identified the target of the autoantibodies as GluN1, suggesting that GluN1-specific immunoglobulin G was successfully induced. Behavior assessment showed that the mice suffered significant cognition impairment and sociability reduction, which is similar to what is observed in patients affected by anti-NMDAR encephalitis. The mice also exhibited impaired long-term potentiation in hippocampal CA1. Pilocarpine-induced epilepsy was more severe and had a longer duration, while no spontaneous seizures were observed.ConclusionThe juvenile mouse model for anti-NMDAR encephalitis is of great importance to investigate the pathological mechanism and therapeutic strategies for the disease, and could accelerate the study of autoimmune encephalitis

14-3-3ζ Interacts with Stat3 and Regulates Its Constitutive Activation in Multiple Myeloma Cells

The 14-3-3 proteins are a family of regulatory signaling molecules that interact with other proteins in a phosphorylation-dependent manner and function as adapter or scaffold proteins in signal transduction pathways. One family member, 14-3-3ζ, is believed to function in cell signaling, cycle control, and apoptotic death. A systematic proteomic analysis done in our laboratory has identified signal transducers and activators of transcription 3 (Stat3) as a novel 14-3-3ζ interacting protein. Following our initial finding, in this study, we provide evidence that 14-3-3ζ interacts physically with Stat3. We further demonstrate that phosphorylation of Stat3 at Ser727 is vital for 14-3-3ζ interaction and mutation of Ser727 to Alanine abolished 14-3-3ζ/Stat3 association. Inhibition of 14-3-3ζ protein expression in U266 cells inhibited Stat3 Ser727 phosphorylation and nuclear translocation, and decreased both Stat3 DNA binding and transcriptional activity. Moreover, 14-3-3ζ is involved in the regulation of protein kinase C (PKC) activity and 14-3-3ζ binding to Stat3 protects Ser727 dephosphorylation from protein phosphatase 2A (PP2A). Taken together, our findings support the model that multiple signaling events impinge on Stat3 and that 14-3-3ζ serves as an essential coordinator for different pathways to regulate Stat3 activation and function in MM cells

Final Setting Judgment and Safety Evaluation of Mass Concrete Based on Strain Monitoring

A judgment method of the final setting time of mass concrete based on strain monitoring and the selection criterion of the starting point of effective deformation are proposed, and the safety of the concrete structure is evaluated based on this. Firstly, the strain monitoring theory of mass concrete is analyzed to clarify the temperature effect component and monitoring mechanism of an early strain of concrete. Then, taking the mass concrete plate of an engineering project as the research object combined with the mechanical analysis, the early strain monitoring data are segmented, and the relationship between the strain response and the temperature in different stages is fitted based on robust regression, so as to explore the correlation between strain and temperature in each stage and better explain the setting process of the concrete structure. Finally, taking the final setting time as the starting point of the effective strain, the safety of the concrete structure is further evaluated. The results show that there is a clear linear relationship between the strain response and temperature, and a high negative correlation between strain and temperature after the final setting. The time point when the frequency modulus corresponding to the strain enters a steady change and decreases with the increase of temperature is taken as the final setting time, which conforms to the concrete condensation mechanism and the temperature effect of early strain monitoring

Underwriter reputation and pricing of risk: evidence from seasoned equity offerings

This paper investigates how underwriter-issuer matching choices and firm risks affect the cost of equity issuance. We show that underwriter-issuer matching is not random; it reflects underwriter reputation and risk concerns, issuers’ quality, and equity market conditions. We apply Heckman self-selection estimation model to control for the endogenous underwriter-issuer matching. We find that the matching choice leads to considerable heterogeneity in pricing of issuer systematic and firm-specific risks in seasoned equity offering (SEO) underwriting fees. Low-reputation underwriters require compensation for bearing issuer’s systematic risk but not for firm-specific risk, while high-reputation underwriters do the opposite. Moreover, evidence in this paper suggests that the underwriter-issuer matching decision entails a non-linear relation between SEO spread and underwriter reputation: high- and low- reputation underwriters earn higher spreads than medium-reputation underwriters. Our findings highlight the importance of accounting for underwriter-issuer matching in assessing SEO underwriting contracts. The results are robust to alternative underwriter reputation measure, model specifications, sample periods, and different samples of firms

The Mediation Role of Safety Attitude in the Impact of Resilience on the Safety Behavior of Coal Miners in China

Resilience can improve the adaptability of coal miners to high-hazard and high-stress environments. After facing setbacks or adversities, resilience can enable coal miners to recover from bad mental states and have an optimistic safety attitude and positive safety behaviors. However, how resilience affects safety behavior and the role of safety attitude in the relationship have not been clear. This study systematically reviewed previous research on resilience, safety attitude, and safety behavior. By recovering 639 valid questionnaires, the validity and reliability of the resilience scale, safety attitude scale, and safety behavior scale for coal miners were verified. Hierarchical regression analysis explored the relationships between resilience, safety attitude, and safety behavior. Studies have shown that resilience positively affects safety attitude and safe behavior. Safety attitude positively affects safety behaviors and plays a role as a partial mediator in the impact of resilience on safe behavior. The theoretical contribution is that the resilience of miners has a positive impact on safety behavior. Moreover, resilience can also act on safety behaviors through the partial intermediation of safety attitude. The practical contribution is that managers of coal mining companies can promote the resilience and safety attitude of coal miners to improve safety behaviors and prevent accidents

The Influence of Tip Clearance on the Performance of a High-Speed Inducer Centrifugal Pump under Different Flow Rates Conditions

The influence mechanism of the blade tip clearance (TC) of an inducer on the performance of a centrifugal pump at high speed was researched under different flow rate conditions in this work. An experiment on the pump’s external performance was carried out, and numerical calculation was also performed under four different TCs. The full characteristic performance curves, static pressure and pressure pulsation distributions of the pump were obtained. Through the research and analysis, it was found that the influence of the TC on the efficiency and the head of the centrifugal pump are related to the flow rate. Under the influence of a large flow rate, the increase in the TC is helpful to improve the efficiency and the head of the pump. The increase in the TC helps to weaken the gap jet effect on the inducer. The inlet jet of the inducer, caused by TC leakage, will form a low-pressure vortex zone at the inlet of the inducer. The splitter-bladed inducer’s pressure pulsation is affected by the TC. The peak pressure pulsation at the monitoring point at the short blades is larger than that at the long blades. With the increase in TC, the cavitation degree at the inlet of the long blade of the inducer is decreased, while the cavitation degree at the short blade is deepened. It is also found that the TC has little effect on the radial force of the inducer and the impeller. These results will provide the design basis for the tip clearance of an inducer

How Safety Climate Impacts Safety Voice—Investigating the Mediating Role of Psychological Safety from a Social Cognitive Perspective

Safety voice has become a popular research topic in the organizational safety field because it helps to prevent accidents. A good safety climate and psychological safety can motivate employees to actively express their ideas about safety, but the specific mechanisms of safety climate and psychological safety, on safety voice, are not yet clear. Based on the “environment-subject cognition-behavior” triadic interaction model of social cognitive theory, this paper explores the relationship between safety climate and safety voice, and the mediating role of psychological safety. We collected questionnaires and conducted data analysis of the valid questionnaires using analytical methods such as hierarchical regression, stepwise regression, and the bootstrap sampling method. We found that safety climate significantly and positively influenced safety voice, and psychological safety played a mediating role between safety climate and safety voice, which strengthened the positive relationship between them. From the research results, it was clear that to stimulate employees to express safety voice behavior, organizations should strive to create a good safety climate and pay attention to building employees’ psychological safety. The findings of this paper provide useful insights for the management of employee safety voice behavior in enterprises