34 research outputs found

    Fatal motor vehicle crashes on road segments in Harbin, China: combining rates into contributory factors

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    In spite of recent advances in traffic surveillance technology and ever-growing concerns over the safety performance improvement, there have been very few conclusive research efforts addressing the segment-involved traffic crashes. This research aims at evaluating the segment-involved crashes using 10 years of documented crash data (2000–2010) in Harbin. The interactions of crash patterns, distribution features, injury severity and potential causes are explored by mining a variety of contributory factors associated with driver demographics, roadway geometric design, environmental state, distribution of traffic flow, etc. Results show that different crash patterns are correlated with a number of risk factors at different roadway locations such as the driver's age and experience, weather, with or without median/division, number of lane, deviation of travelling speed, Annual Average Daily Traffic (AADT), volume to capacity ratio (v/c), and so on, and different combinations of factors may lead to some specific crash patterns such as head-on, angle or rear-end collisions. Moreover, four black locations with a huge number of crashes are identified due to heavy truck involvement on these in/out roads. These findings will help to better understand what, when and why these crashes occur and develop more targeted and cost-effective countermeasures to enhance the overall safety performance of the roadway network

    Improving schedule adherence based on dynamic signal control and speed guidance in connected bus system

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    Purpose – The purpose of this paper is to develop a dynamic control method to improve bus schedule adherence under connected bus system. Design/methodology/approach – The authors developed a dynamic programming model that optimally schedules the bus operating speed at road sections and multiple signal timing plans at intersections to improve bus schedule adherence. First, the bus route was partitioned into three types of sections: stop, road and intersection. Then, transit agencies can control buses in real time based on all collected information; i.e. control bus operating speed on road sections and adjust the signal timing plans through signal controllers to improve the schedule adherence in connected bus environment. Finally, bus punctuality at the downstream stop and the saturation degree deviations of intersections were selected as the evaluation criteria in optimizing signal control plans and bus speeds jointly. Findings – An illustrative case study by using a bus rapid transit line in Jinan city was performed to verify the proposed model. It revealed that based on the proposed strategy, the objective value could be reduced by 73.7%, which indicated that the punctuality was highly improved but not to incur excessive congestion for other vehicular traffic. Originality/value – In this paper, the authors applied speed guidance and the adjustment of the signal control plans for multiple cycles in advance to improve the scheduled stability; furthermore, the proposed control strategy can reduce the effect on private traffics to the utmost extend

    Myocardial Fibrosis in the Pathogenesis, Diagnosis, and Treatment of Hypertrophic Cardiomyopathy

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    Hypertrophic cardiomyopathy (HCM) is a type of hereditary cardiomyopathy caused by gene mutation. Its histological features include cardiomyocyte hypertrophy and disarray as well as myocardial fibrosis. Gene mutation, abnormal signal transduction, and abnormal energy metabolism are considered the main mechanisms of myocardial fibrosis. There is a strong correlation between myocardial fibrosis and the occurrence, development, and prognosis of HCM. We review the application of myocardial fibrosis in the diagnosis and treatment of HCM, focusing on research progress and the application of magnetic resonance imaging on the basis of the characteristics of fibrosis in the diagnosis and prognosis of HCM. </p

    Protection motivation theory in predicting intentional behaviors regards schistosomiasis: a WeChat-based qualitative study

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    BackgroundModifications of behavior can help reduce the risk of transmission by disrupting the parasite life cycle. Behavior intension is a necessary intermediate step in behavior change. This study aimed to explore protection motivation theory (PMT) in predicting likelihood of engagement in protective behavior against infection with Schistosoma.MethodsIn China, a questionnaire for data collection was sent to users who followed the WeChat public account from June 2 to 6, 2023. Factors affecting intentional behavior of participants were analyzed using stepwise regression analysis and structural equation modeling.ResultsA total of 2,243 valid questionnaires were collected, with a mean age of 30 ± 8.4 years. Approximately 1,395 (62.2%) participants reported that they had been exposed to wild waters in daily work and life. About 51.0 and 50.7% of respondents reported never having been exposed to wild water in the last 3 and 6 months, respectively. Results indicated that prior knowledge of schistosomiasis was associated with the 7 PMT subconstructs, which then influenced future preventative behaviors.ConclusionBehavior intentionis a complicated and indispensable part of behavior change that is influenced by professional knowledge, socio-economic status, and personal characteristics. The effective dissemination of knowledge regards schistosomiasis should be strengthened to emphasize the effectiveness of protective measures against infection and severe disease

    Peripheral cutaneous synucleinopathy characteristics in genetic Parkinson’s disease

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    BackgroundCutaneous phosphorylated alpha-synuclein (p-α-syn) deposition is an important biomarker of idiopathic Parkinson’s disease (iPD). Recent studies have reported synucleinopathies in patients with common genetic forms of PD.ObjectiveThis study aimed to detect p-α-syn deposition characteristic in rare genetic PD patients with CHCHD2 or RAB39B mutations. Moreover, this study also aimed to describe peripheral alpha-synuclein prion-like activity in genetic PD patients, and acquire whether the cutaneous synucleinopathy characteristics of genetic PD are consistent with central neuropathologies.MethodsWe performed four skin biopsy samples from the distal leg (DL) and proximal neck (C7) of 161 participants, including four patients with CHCHD2 mutations, two patients with RAB39B mutations, 16 patients with PRKN mutations, 14 patients with LRRK2 mutations, five patients with GBA mutations, 100 iPD patients, and 20 healthy controls. We detected cutaneous synucleinopathies using immunofluorescence staining and a seeding amplification assay (SAA). A systematic literature review was also conducted, involving 64 skin biopsies and 205 autopsies of genetic PD patients with synucleinopathy.ResultsP-α-syn was deposited in the peripheral cutaneous nerves of PD patients with CHCHD2, LRRK2, or GBA mutations but not in those with RAB39B or PRKN mutations. There were no significant differences in the location or rate of α-syn-positive deposits between genetic PD and iPD patients. Peripheral cutaneous synucleinopathy appears to well represent brain synucleinopathy of genetic PD, especially autosomal dominant PD (AD-PD). Cutaneous α-synuclein SAA analysis of iPD and LRRK2 and GBA mutation patients revealed prion-like activity.ConclusionP-α-syn deposition in peripheral cutaneous nerves, detected using SAA and immunofluorescence staining, may serve as an accurate biomarker for genetic PD and iPD in the future

    Research on Safety and Static-Dynamic Legibility of Distressed Pavement

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    In order to study the impacts of distressed pavement on driving safety, the drivers’ driving behavior and driving characteristics need to be analyzed. By analyzing the drivers’ characteristics, driving behavior’ and braking characteristics of vehicles, relation between static legibility distance of the distressed pavement under different driving conditions and dynamic legibility distance during driving is revealed via statistical analysis. The relation between vehicle speeds, braking performance, and the minimum safety legibility distance is developed. The recommended static legibility distances for different speed limits are proposed, which would be useful to improve the driving safety under adverse road conditions

    Analysis and Prediction of Pedestrians’ Violation Behavior at the Intersection Based on a Markov Chain

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    Pedestrian violations pose a danger to themselves and other road users. Most previous studies predict pedestrian violation behaviors based only on pedestrians’ demographic characteristics. In practice, in addition to demographic characteristics, other factors may also impact pedestrian violation behaviors. Therefore, this study aims to predict pedestrian crossing violations based on pedestrian attributes, traffic conditions, road geometry, and environmental conditions. Data on the pedestrian crossing, both in compliance and in violation, were collected from 10 signalized intersections in the city of Jinhua, China. We propose an illegal pedestrian crossing behavior prediction approach that consists of a logistic regression model and a Markov Chain model. The former calculates the likelihood that the first pedestrian who decides to cross the intersection illegally within each signal cycle, while the latter computes the probability that the subsequent pedestrians who decides to follow the violation. The proposed approach was validated using data gathered from an additional signalized intersection in Jinhua city. The results show that the proposed approach has a robust ability in pedestrian violation behavior prediction. The findings can provide theoretical references for pedestrian signal timing, crossing facility optimization, and warning system design

    Effective Synthesis of Nucleosides Utilizing O-Acetyl-Glycosyl Chlorides as Glycosyl Donors in the Absence of Catalyst: Mechanism Revision and Application to Silyl-Hilbert-Johnson Reaction

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    An effective synthesis of nucleosides using glycosyl chlorides as glycosyl donors in the absence of Lewis acid has been developed. Glycosyl chlorides have been shown to be pivotal intermediates in the classical silyl-Hilbert-Johnson reaction. A possible mechanism that differs from the currently accepted mechanism advanced by Vorbrueggen has been proposed and verified by experiments. In practice, this catalyst-free method provides easy access to Capecitabine in high yield

    PTF-SimCM: A Simple Contrastive Model with Polysemous Text Fusion for Visual Similarity Metric

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    Image similarity metric, also known as metric learning (ML) in computer vision, is a significant step in various advanced image tasks. Nevertheless, existing well-performing approaches for image similarity measurement only focus on the image itself without utilizing the information of other modalities, while pictures always appear with the described text. Furthermore, those methods need human supervision, yet most images are unlabeled in the real world. Considering the above problems comprehensively, we present a novel visual similarity metric model named PTF-SimCM. It adopts a self-supervised contrastive structure like SimSiam and incorporates a multimodal fusion module to utilize textual modality correlated to the image. We apply a cross-modal model for text modality rather than a standard unimodal text encoder to improve late fusion productivity. In addition, the proposed model employs Sentence PIE-Net to solve the issue caused by polysemous sentences. For simplicity and efficiency, our model learns a specific embedding space where distances directly correspond to the similarity. Experimental results on MSCOCO, Flickr 30k, and Pascal Sentence datasets show that our model overall outperforms all the compared methods in this work, which illustrates that the model can effectively address the issues faced and enhance the performances on unsupervised visual similarity measuring relatively

    Bayesian hierarchical spatial count modeling of taxi speeding events based on GPS trajectory data.

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    Speeding behavior, especially serious speeding, is more common in taxi driver than other driving population due to their high exposure under traffic environment, which increases the risk of being involved in crashes. In order to prevent the taxi and other road users from speed-related crash, previous studies have revealed contributors of demographic and driving operation affecting taxi speeding frequency. However, researches regarding road factors, and spatial effect are typically rare. For this sake, the current study explores the contributions of 10 types of road characteristics and two kinds of spatial effects (spatial correlation and spatial heterogeneity) on taxi total speeding and serious speeding frequency. Taxi GPS trajectory data in a Chinese metropolis were used to identify speeding event. The study then established four kinds of Bayesian hierarchical count models base on Poisson and negative binominal distribution to estimate the contributor impacts, respectively. Results show that Bayesian hierarchical spatial Poisson log-linear model is optimum for fitting both total and serious speeding frequency. For the analysis, it is found that drivers are more likely to commit speeding on long multilane road with median strip, and road with non-motorized vehicle lane, bus-only lane and viaduct or road tunnel. Roads with low speed limit, and work zone are associated with increasing speeding as well. In terms of serious speeding, bus-only lane is not a contributor, while road speed camera number and one-way organization are significantly positive to the speeding frequency. Furthermore, it reveals that two spatial effects significantly increase the occurrence of speeding events; the impact of spatial heterogeneity is more critical
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