RESUMO
Existing research rarely examines the subjective and objective built environment of river valley-type cities in relation to travel mode choice, particularly overlooking the heterogeneity among travelers in these cities. In this paper, based on questionnaire survey data and built environment data, terrain spatial perception (TSP) is introduced to expand the theory of planned behavior (TPB), and a Structural Equation Model (SEM) is established. Factor analysis and path analysis are conducted using SPSS and AMOS to estimate latent variables. An integrated model of SEM and random parameter Logit model (RPLM), which can not only analyze the psychological perception factors of commuters in river valley-type cities but also consider the heterogeneity of psychological perception, was constructed to analyze the impact of personal attributes, objective built environment factors, and psychological latent variables on the commuting mode choice behavior of public transport users in river valley-type cities. The results indicate that the five observation indicators corresponding to the proposed terrain spatial perception latent variables can better explain the terrain spatial perception of commuters in river valley-type cities. Different from plain cities, the subjective and objective built environment of river valley-type cities notably influence the travel behavior of commuters. Moreover, the parameters of terrain spatial perception follow a normal distribution, indicating that the sensitivity of different commuters to the terrain spatial perception of river valley-type cities is heterogeneous. The results of our study can provide a reference for alleviating traffic issues in valley cities.
RESUMO
To address the problem of difficult performance assessment of train control on-board system after recovery from failures, we have proposed a resilience assessment methodology that uses reliability as an indicator of system resilience. Since the system failures are time-dependent, we adopted the Discrete Time Bayesian Network method to obtain the system's reliability before and after failure. Subsequently, we used an exponential recovery model to quantify the system's performance curve during the recovery phase, and finally utilized the resilient triangle area method to quantify its resilience size. Analyzing the CTCS3-300T train control on-board system, we found that the resilience of the system with cold standby redundancy design and hot standby redundancy design were 89.44 % and 87.34 %, respectively, indicating a slight decrease in system performance after recovery from failures compared to pre-failure levels. At that time, it was necessary to adjust operational plans based on actual conditions to avoid greater impact on the railway network. This paper realizes performance resilience of train control on-board system after failure recovery, which can be applied to similar systems and provide theoretical references for realizing intelligent maintenance of the high-speed train.
RESUMO
BACKGROUND AND OBJECTIVE: Nerve growth factor (NGF) contributes to airway inflammation and bronchoconstriction in allergic asthma. The Src homology 2beta/serine/threonine kinase (SH2-Bbeta/Akt) pathway is one of the avenues through which NGF regulates the biological activity of pheochromocytoma (PC)12 cells. It has also been reported that NGF upregulates the expression of SH2-Bbeta in the lung tissue of asthmatic mice. The present study investigated the effects of NGF and SH2-Bbeta on Akt activation during allergic airway challenge. METHODS: BALB/c mice were sensitized and challenged with ovalbumin. The effects of NGF and SH2-Bbeta on Akt in allergic airway challenge were assessed by intravenously administering anti-NGF antibody or a mutant of SH2-Bbeta (R555E) to these mice. Pulmonary histological changes were then assessed and the inflammatory cells in the BAL fluid (BALF) were counted. Additionally, phosphorylated Akt (p-Akt) expression was determined by fluorescence microscopy, western blotting and quantitative RT-PCR. Airway resistance was also measured using closed-type body plethysmography. RESULTS: We observed p-Akt overexpression in the lungs after allergen challenge by fluorescence microscopy, Western blotting and RT-PCR, as compared with the control. However, after treatment with anti-NGF or R555E, p-Akt levels and allergen-induced airway inflammation were reduced in comparison with those of allergen-challenged mice. Anti-NGF and R555E also decreased airway hyperresponsiveness caused by allergen challenge in response to methacholine (MCH). CONCLUSIONS: These results suggest that SH2-Bbeta regulation of Akt partly participates in the NGF-mediated development of allergic airway challenge.
