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Detecting remotely triggered temporal changes around the Parkfield section of the San Andreas fault

Earthquake Science 2010年第5期23卷 497-509页

作者： Peng Zhao Zhigang Peng karim ghazi sabra School of Earth and Atmospheric Science Georgia Institute of Technology Atlanta GA 30338 USA School of Mechanical Engineering Georgia Institute of Technology Atlanta GA 30338 USA

Detecting temporal changes in fault zone properties at seismogenic depth have been a long-sought goal in the seismological community for many decades. Recent studies based on waveform analysis of repeating earthquakes have found clear temporal changes in the shallow crust and around active fault zones associated with the occurrences of large nearby and teleseismic earthquakes. However, repeating earthquakes only occur in certain locations and their occurrence times cannot be controlled, which may result in inadequate sampling of the interested regions or time periods. Recent developments in passive imaging via auto- and cross-correlation of ambient seismic wavefields （e.g., seismic noise, earthquake coda waves） provide an ideal source for continuous monitoring of temporal changes around active fault zones. Here we conduct a systematic search of temporal changes along the Parkfield section of the San Andreas fault by cross-correlating relatively high-frequency （0.4-1.3 Hz） ambient noise signals recorded by 10 borehole stations in the High Resolution Seismic Network. After using stretch/compressed method to measure the delay time and the decorrelation-index between the daily noise cross-correlation functions （NCCFs）, we find clear temporal changes in the median seismic velocity and decorrelation-index associated with the 2004 M6.0 Parkfield earthquake. We also apply the same procedure to the seismic data around five regional/teleseismic events that have triggered non-volcanic tremor in the same region, but failed to find any clear temporal changes in the daily NCCFs. The fact that our current technique can detect temporal changes from the nearby but not regional and teleseismic events, suggests that temporal changes associated with distance sources are very subtle or localized so that they could not be detected within the resolution of the current technique （-0.2%）.

关键词： temporal changes remote triggering seismic noise cross-correlation interferometry seismic coda

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Influence of warm eddies on sound propagation in the Gulf of Mexico

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Chinese Physics B 2019年第5期28卷 134-144页

作者： Yao Xiao Zhenglin Li Jun Li Jiaqi Liu State Key Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences University of Chinese Academy of Sciences China State Shipbuilding Corporation (CSSC) Systems Engineering Research Institute College of Underwater Acoustic Engineering Harbin Engineering University Woodruff School Mechanical Engineering Georgia Institute of Technology

An automatic detection method is employed to identify and track eddies in the Gulf of Mexico. The physical parameters of the eddies, such as lifespan, radius, and distribution position are first examined and used to determine the spatio–temporal evolution of a strong warm eddy separated from the Mexico current. Then, the influence of this strong warm eddy on sound propagation during its lifespan are comprehensively analyzed with the parabolic equation and explained by using the normal mode and ray theories. Additionally, the influence of mesoscale eddies on the redistribution of total depth-integrated energy among the normal modes in the deep water is also discussed. The variation of arrival angle is investigated to explain the spreading acoustic energy caused by eddies. Overall, the results show that warm eddies can change the propagation paths and cause the convergence zone to broaden and approach the sound source. Moreover,the warm eddy can disperse sound energy and cause the total depth-integrated energy to incline to a lower normal *** the whole of these three periods(eddy generating, eddy maturing, and eddy terminating), the fluctuation in the transmission loss is up to 30 dB(depending on the relative location of eddy center to the source).

关键词： mesoscale eddies sound propagation mode coupling acoustic energy disturbance

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Stem cell transplantation in cerebrovascular accidents:A global bibliometric analysis(2000-2023)

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World Journal of Stem Cells 2024年第9期16卷 832-841页

作者： Jad El Masri Ahmad Afyouni Maya ghazi karim Hamideh Israe Moubayed Abdo Jurjus Hanine Haidar Ruzanna Petrosyan Pascale Salameh Hassan Hosseini École Doctorale Sciences de la Vie et de la Santé UniversitéParis-Est CréteilCréteil 94010France INSERM U955-E01 Institut Mondor de Recherche BiomédicaleUniversitéParis-Est CréteilCréteil 94000France Faculty of Medical Sciences Lebanese UniversityBeirut 1533Lebanon Department of Anatomy Cell Biology and Physiological SciencesFaculty of MedicineAmerican University of BeirutBeirut 1107Lebanon Department of Neurology Faculty of MedicineLebanese American UniversityBeirut 1102Lebanon Department of Pathology Faculty of MedicineLebanese American UniversityBeirut 1102Lebanon Faculty of Pharmacy Lebanese UniversityBeirut 1102Lebanon Faculty of Medicine Lebanese American UniversityBeirut 1102Lebanon Department of Primary Care and Population Health University of Nicosia Medical SchoolNicosia 2408Cyprus Institut National de SantéPublique d'Épidémiologie Clinique et de Toxicologie-Liban Beirut 1103Lebanon Department of Neurology Henri Mondor HospitalAP-HPCréteil 94000France

BACKGROUND Cerebrovascular accident(CVA)is a major global contributor to death and *** part of its medical management,researchers have recognized the importance of promising neuroprotective strategies,where stem cell transplantation(SCT)is thought to confer advantages via trophic and neuroprotective *** To evaluate the current state of research on SCT in patients with CVA,assess key trends and highlight literature *** PubMed was screened for SCT in CVA-related articles in October 2023,for each country during the period between 2000 and *** the World Bank data,total population and gross domestic product were collected for ***_1.6.19 was used to create the VOS figure using the results of the same *** and tables were obtained using Microsoft Office *** A total of 6923 studies were identified on SCT in CVA,making 0.03%of all published studies ***,68%were conducted in high-income countries,with a significant focus on mesenchymal stem *** journal“Stroke”featured the largest share of these articles,with mesenchymal SCT having the highest rate of inclusion,followed by hematopoietic *** time,there has been a noticeable shift from in vitro studies,which assess stem cell proliferation and neurogenesis,to in vivo studies aimed at evaluating efficacy and ***,the number of reviews increased along this *** This bibliometric analysis provides a comprehensive guide for physicians and researchers in the field through an objective overview of research activity,and highlights both current trends and *** a potential therapeutic role in CVA,more research is needed in the future to focus on different aspects of SCT,aiming to reach a better treatment strategy and improve life quality in patients.

关键词： Bibliometric analysis PubMed Stem cell transplantation Cerebrovascular accidents Stroke

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Performance Evaluation of Edge Detection Using Sobel, Homogeneity and Prewitt Algorithms

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Journal of Software Engineering and Applications 2018年第11期11卷 537-551页

作者： Abdel karim M. Baareh Ahmad Al-Jarrah Ahmad M. Smadi ghazi H. Shakah Computer Science Department Ajloun College Al-Balqa Applied University Ajloun Jordan Computer Science Department Ajloun National University Ajloun Jordan

Edge detection considered as very important and fundamental tool in image processing. An image edge is a very sensitive place where the image information and details mostly placed on it. Different filters were used to detect and enhance these edges to improve the sharpness and raising the image clarity. The significance of this paper comes from the study, compare and evaluate the effects of three well-known edge detection techniques in a spatial domain, where this evaluation was performed using both subjective and objective manner to find out the best edge detection algorithm. The Sobel, Homogeneity and Prewitt algorithms were used on 2D gray-scale synthesis and real images in Jordan using C# programming language. According to the comparative results obtained using the three techniques, it was clearly found that Prewitt and Homogeneity algorithms performance were better than Sobel algorithm. Therefore, Prewitt and Homogeneity algorithms can be recommended as useful detection tools in edge detection.

关键词： Edge Detector Edge Enhancement Edge Localization Smoothing Image Processing

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