Variations in oceanic plate bending along the Mariana trench

Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Earth and Planetary Science Letters 401 (2014): 206-214, doi:10.1016/j.epsl.2014.05.032.We quantify along-trench variations in plate flexural bending along the Mariana trench in the western Pacific Ocean. A 3-D interpreted flexural deformation surface of the subducting Pacific Plate was obtained by removing from the observed bathymetry the effects of sediment loading, isostatically-compensated topography based on gravity modeling, age-related lithospheric thermal subsidence, and residual short-wavelength features. We analyzed flexural bending of 75 across-trench profile sections and calculated five best-fitting tectonic and plate parameters that control the flexural bending. Results of analysis revealed significant along-trench variations: the trench relief varies from 0.9 to 5.7 km, trench-axis vertical loading (-V0) from -0.73 × 1012 to 3.17 × 1012 N/m, and axial bending moment (-M0) from 0.1 × 1017 to 2.7× 1017 N. The effective elastic plate thickness seaward of the outer-rise region (Te M) ranges from 45 to 52 km, while that trench-ward of the outer-rise (Te m) ranges from 19 to 40 km. This corresponds to a reduction in Te of 21-61%. The transition from Te M to Te m occurs at a breaking distance of 60-125 km from the trench axis, which is near the outer-rise and corresponds to the onset of observed pervasive normal faults. The Challenger Deep area is associated with the greatest trench relief and axial vertical loading, while areas with seamounts at the trench axis are often associated with more subtle trench relief, smaller axial vertical loading, and greater topographic bulge at the outer-rise.This work was supported by US NSF Grant OCE-1141985 and Deerbrook Foundation (J.L.), NSF-China Grant 41376063 and Joint NSF China/Guangdong Natural Science Fund Committee U0933006 (W.Z.), and the Chinese Scholarship Council (F.Z.)

Intra- and intertrench variations in flexural bending of the Manila, Mariana and global trenches : implications on plate weakening in controlling trench dynamics

Author Posting. © Author(s), 2017. This article is posted here by permission of Oxford University Press for personal use, not for redistribution. The definitive version was published in Geophysical Journal International 212 (2018): 1429–1449, doi:10.1093/gji/ggx488.We conducted detailed analyses of a global array of trenches, revealing systematic intra- and intertrench variations in plate bending characteristics. The intratrench variations of the Manila and Mariana Trenches were analysed in detail as end-member cases of the relatively young (16–36 Ma) and old (140–160 Ma) subducting plates, respectively. Meanwhile, the intertrench variability was investigated for a global array of additional trenches including the Philippine, Kuril, Japan, Izu-Bonin, Aleutian, Tonga-Kermadec, Middle America, Peru, Chile, Sumatra and Java Trenches. Results of the analysis show that the trench relief (W0) and width (X0) of all systems are controlled primarily by the faulting-reduced elastic thickness near the trench axis (Tme) and affected only slightly by the initial unfaulted thickness (TMe) of the incoming plate. The reduction in Te has caused significant deepening and narrowing of trench valleys. For the cases of relatively young or old plates, the plate age could be a dominant factor in controlling the trench bending shape, regardless the variations in axial loadings. Our calculations also show that the axial loading and stresses of old subducting plates can vary significantly along the trench axis. In contrast, the young subducting plates show much smaller values and variations in axial loading and stresses.This work was supported by Chinese Academy of Sciences Grants (Y4SL021001, QYZDY-SSW-DQC005, YZ201325 and YZ201534), National Natural Science Foundation of China Grants (91628301, U1606401, 41376063 and 41706056) and HKSAR Research Grant Council Grants (24601515, 14313816)

Carotid Atherosclerosis Detected by Ultrasonography: A National Cross‐Sectional Study

Background: Carotid atherosclerosis (CA) is a reflector of generalized atherosclerosis that is associated with systemic vascular disease. Data are limited on the epidemiology of carotid lesions in a large, nationally representative population sample. We aimed to evaluate the prevalence of CA detected by carotid ultrasonography and related risk factors based on a national survey in China. Methods and Results: A total of 107 095 residents aged ≥40 years from the China National Stroke Prevention Project underwent carotid ultrasound examination. Participants with carotid endarterectomy or carotid stenting and those with stroke or coronary heart disease were excluded. Data from 84 880 participants were included in the analysis. CA was defined as increased intima–media thickness (IMT) ≥1 mm or presence of plaques. Of the 84 880 participants, 46.4% were men, and the mean age was 60.7±10.3 years. The standardized prevalence of CA was 36.2% overall, increased with age, and was higher in men than in women. Prevalence of CA was higher among participants living in rural areas than in urban areas. Approximately 26.5% of participants had increased IMT, and 13.9% presented plaques. There was an age‐related increase in participants with increased IMT, plaque presence, and stenosis. In multiple logistic regression analysis, older age, male sex, residence in rural areas, smoking, alcohol consumption, physical inactivity, obesity, hypertension, diabetes mellitus, and dyslipidemia were associated with CA. Conclusions: CA was highly prevalent in a middle‐aged and older Chinese population. This result shows the potential clinical importance of focusing on primary prevention of atherosclerosis progression

Design and synthesis of unique indole-benzosulfonamide oleanolic acid derivatives as potent antibacterial agents against MRSA.

The rapid emergence of antibiotic resistance and the scarcity of novel antibacterial agents have necessitated an urgent pursuit for the discovery and development of novel antibacterial agents against multidrug-resistant bacteria. This study involved the design and synthesis of series of novel indole-benzosulfonamide oleanolic acid (OA) derivatives, in which the indole and benzosulfonamide pharmacophores were introduced into the OA skeleton semisynthetically. These target OA derivatives show antibacterial activity against Staphylococcus strains in vitro and in vivo. Among them, derivative c17 was the most promising antibacterial agent while compared with the positive control of norfloxacin, especially against methicillin-resistant Staphylococcus aureus (MRSA) in vitro. In addition, derivative c17 also showed remarkable efficacy against MRSA-infected murine skin model, leading to a significant reduction of bacterial counts during this in vivo study. Furthermore, some preliminary studies indicated that derivative c17 could effectively inhibit and eradicate the biofilm formation, disrupt the integrity of the bacterial cell membrane. Moreover, derivative c17 showed low hemolytic activity and low toxicity to mammalian cells of NIH 3T3 and HEK 293T. These aforementioned findings strongly support the potential of novel indole-benzosulfonamide OA derivatives as anti-MRSA agents

Bifurcation analysis of macroscopic traffic flow model based on the influence of road conditions

summary:A macroscopic traffic flow model considering the effects of curves, ramps, and adverse weather is proposed, and nonlinear bifurcation theory is used to describe and predict nonlinear traffic phenomena on highways from the perspective of global stability of the traffic system. Firstly, the stability conditions of the model shock wave were investigated using the linear stability analysis method. Then, the long-wave mode at the coarse-grained scale is considered, and the model is analyzed using the reduced perturbation method to obtain the Korteweg-de Vries (KdV) equation of the model in the sub-stable region. In addition, the type of equilibrium points and their stability are discussed by using bifurcation analysis, and a theoretical derivation proves the existence of Hopf bifurcation and saddle-knot bifurcation in the model. Finally, the simulation density spatio-temporal and phase plane diagrams verify that the model can describe traffic phenomena such as traffic congestion and stop-and-go traffic in real traffic, providing a theoretical basis for the prevention of traffic congestion

Equilibrium Point analysis of macro traffic flow model considering the influence of front and rear lights

In this paper, the traveling wave solution of the macro continuum model considering the automobile tail lamp effect is obtained by using the phase plane analysis method, the type of equilibrium point of the model is determined, and the stability of the system at the equilibrium point is analyzed. This method can describe and predict the nonlinear traffic phenomena on Expressway from the perspective of system global stability. According to the theory of differential equation, the model is further analyzed to judge the type and stability of equilibrium point. Finally, the simulation diagram is used for numerical simulation. Through numerical verification, it is concluded that the numerical results are consistent with the theoretical analysis

Analysis of equilibrium point based on nonlinear traffic flow model

In this paper, the traveling wave solution of Kerner konhauser model is obtained by phase plane analysis method, and a new model suitable for stability analysis is obtained by variable transformation. The new model can describe and predict the nonlinear traffic phenomenon on Expressway from the perspective of system global stability. In this paper, the nonlinear system and linear system are obtained respectively by traveling wave substitution and Taylor expansion at the equilibrium point. According to the qualitative theory of differential equations, the equilibrium point type and stability of the linear system are determined. Finally, the simulation results show the consistency between the numerical results and the theoretical analysis