Mass and heat transfer processes in magmatic orogens driven by magmatism, tectonic deformation, and surface erosion

Magmatic orogens are continental arcs and collisional belts that are associated with syn-tectonic magmatism. They record heat and mass transfer processes acting from the mantle to the surface. While magmatism, deformation, and surface erosion each take place at various depth levels, they are dynamically linked processes through interaction in the lithosphere. This dissertation presents an investigation of how heat and mass transfer processes in the lithosphere affect the evolution of magmatic orogens. I first present an evaluation of magma genesis resulting from partial melting of underthrusted lower crust. The causes of episodic magmatism in the Mesozoic Sierra Nevada continental magmatic arc and the sources of high-magma flux (flare-ups) are under debate. Here, I use the results of numerical modeling and scaling analysis to assess the mass balance and thermodynamic feasibility of generating arc magma as a result of partial melting of underthrusted lower crust. I show with a constant underthrusting rate of 5 km/Myr, the magmatic thickening rate is 0.1-0.3 km/Myr, accounting for 10-30% of the magmatic thickening rate during a flare-up. The cumulative volume of magma generated from the partial melting of a 20-km-thick underthrusted lower crust is on the order of 105 km3, ~10-40% of the estimated magma volume generated during a flare-up. Therefore, the results show that partial melting of underthrusted lower crust plays a subsidiary role in driving a magmatic flare-up event. Additional magma derived from the mantle and/or other crustal sources are needed to achieve the observed magmatic output during flare-ups. However, the arc root developed by partial melting of the underthrusted crust reduces the time needed to obtain the critical thickness for root foundering, thus influencing the tempo of arc magmatism. As magma ascends into the crust, its interactions with the deforming crust are recorded in the exhumation history of a tilted crustal section and fabrics in plutons. The Gangdese Batholith is well exposed in southern Tibet and presents a unique opportunity to investigate the evolution of a continental arc from subduction to collision. I applied Al-in-hornblende barometry across the eastern Gangdese Batholith to obtain pluton emplacement pressures to identify potential spatial trends in bedrock pressure. The results reveal a regional paleo-depth pattern with plutons emplaced at 1-2 kbar in the west near Lhasa that deepens to 6-12 kbars in the east, near Nyingchi. By coupling the pressure data with U-Pb zircon ages, I estimate the exhumation history of the Gangdese Batholith since 100 Ma and show a sequence of exhumation and burial phases as well as the expected changes in crustal thickness, reflecting major tectonic events including the development of a continental arc and the India-Asia continent-continent collision. I hypothesize that the Gangdese Batholith was tilted due to differential exhumation along the E-W direction since ~10 Ma, associated with the formation of the eastern Himalayan syntaxis. Along with the exhumation history, I also studied fabrics recorded by the Gangdese plutons and report magmatic fabric measurements from the eastern Gangdese Batholith, aimed to decipher the crustal response to changes in India-Asia convergence style from subduction to collision. Results show magmatic fabric orientations are variable through time and represent: (1) a pre-collision Late Cretaceous subduction phase of orogen-perpendicular contraction and crustal thickening. (2) Transitional Paleocene-Eocene crustal thinning and a change in crustal contraction stress from ~N-S to ~E-W. (3) Post-Eocene crustal thickening without a clear, dominant principal stress direction. The pre-collision Late Cretaceous fabrics are interpreted to record approximate head-on subduction of the Neo-Tethyan oceanic plate beneath the Asian continent, while the post-collision fabrics reflect the enigmatic nature of the India-Asia collision, as well as the complexity of the post-collisional processes. Motivated by the recognition of the tilted Gangdese crust, I explored the role of surface erosion in driving solid earth processes. Particularly, whether erosion-driven rock uplift is responsible for the rapid exhumation of the eastern Himalayan syntaxis (EHS). Results of numerical simulations show that localized surface erosion (5 km/Myr) is able to exhume lower crust from depths of >40 km on timescale of ~10 Myr, produce high topography, and generate partial melt in the lower crust. Erosion-driven advection elevates the local geothermal gradient and reduces crustal viscosity, promoting deformation. Exhumation is sustained by isostatic flow resulting from lithostatic pressure difference and amplified by crustal diapirism, associated with the presence of hot and buoyant molten rocks in the weakened advection channel. Such diapiric upwellings trigger a rapid acceleration in rock uplift rates to values greater than the driving erosional forcing and cause localized surface uplift, resulting in topography higher than surrounding regions. The erosion-driven exhumation model demonstrates the intricate coupling between surface erosion and rock uplift, as well as the active role of surface erosion in driving orogenic evolution

A novel fault-tolerant control strategy for near space hypersonic vehicles via least squares support vector machine and backstepping method

Near Space Hypersonic Vehicle (NSHV) could play significant roles in both military and civilian applications. It may cause huge losses of both personnel and property when a fatal fault occurs. It is therefore paramount to conduct fault-tolerant research for NSHV and avoid some catastrophic events. Toward this end, this paper presents a novel fault-tolerant control strategy by using the LSSVM (Least Squares Support Vector Machine)-based inverse system and Backstepping method. The control system takes advantage of the superiority of the LSSVM in solving the problems with small samples, high dimensions and local minima. The inverse system is built with an improved LSSVM. The adaptive controller is designed via the Backstepping which has the unique capability in dealing with nonlinear control systems. Finally, the experiment results demonstrate that the proposed method performs well

Have tax reduction and fee reduction promoted the development of the financial industry?—Empirical evidence based on listed companies in the financial industry

Finance plays an important role in China’s new development pattern, and the financial industry is also a crucial part of the country’s economic growth. This paper selects the four financial index data of 76 listed companies in the financial profile of Hithink RoyalFlush stocks and the consolidated balance sheet and consolidated income statement in the China Stock Market Accounting Research (CSMAR) database, empirically studies the impact of tax reduction and fee reduction on the financial industry through the Panel Vector Autoregression (PVAR) model, and gives relevant suggestions. The results show that: (1) The implementation of tax reduction and fee reduction policy makes the net profit available to the financial industry increase in the short term, but the long-term effect is not obvious. (2) The reduction of the tax burden will significantly increase the net sales interest rate of the financial industry within one year, and then the fluctuation in the impact tends to 0. (3) The reduction of the tax burden will lead to the reduction of financial enterprises’ sense of hardship in a certain period of time, which will lead to the reduction of the total asset turnover rate. (4) The reduction of the tax burden will increase the debt-to-asset ratio of financial enterprises within two years, thus increasing financial risk. The research not only provides a theoretical analysis and policy basis for the analysis of the impact of tax reduction on the financial industry but also provides decision support for tax reduction policies to revitalize industry development, stimulate financial market activities, ensure direct access to financial resources to enterprises, and further increase the market activities of the whole society

Integrating Visual Foundation Models for Enhanced Robot Manipulation and Motion Planning: A Layered Approach

This paper presents a novel layered framework that integrates visual foundation models to improve robot manipulation tasks and motion planning. The framework consists of five layers: Perception, Cognition, Planning, Execution, and Learning. Using visual foundation models, we enhance the robot's perception of its environment, enabling more efficient task understanding and accurate motion planning. This approach allows for real-time adjustments and continual learning, leading to significant improvements in task execution. Experimental results demonstrate the effectiveness of the proposed framework in various robot manipulation tasks and motion planning scenarios, highlighting its potential for practical deployment in dynamic environments.Comment: 3 pages, 2 figures, IEEE Worksho

Role of adenosine signaling in penile erection and erectile disorders.

INTRODUCTION: Penile erection is a hemodynamic process, which results from increased flow and retention of blood in the penile organ due to the relaxation of smooth muscle cells. Adenosine, a physiological vasorelaxant, has been shown to be a modulator of penile erection. AIM: To summarize the research on the role of adenosine signaling in normal penile erection and erectile disorders. MAIN OUTCOME MEASURES: Evidence in the literature on the association between adenosine signaling and normal and abnormal penile erection, i.e., erectile dysfunction (ED) and priapism. METHODS: The article reviews the literature on the role of endogenous and exogenous adenosine in normal penile erection, as well as in erectile disorders namely, ED and priapism. RESULTS: Adenosine has been shown to relax corpus cavernosum from various species including human in both in vivo and in vitro studies. Neuromodulatory role of adenosine in corpus cavernosum has also been demonstrated. Impaired adenosine signaling through A(2B) receptor causes partial resistance of corpus cavernosum, from men with organic ED, to adenosine-mediated relaxation. Increased level of adenosine has been shown to be a causative factor for priapism. CONCLUSION: Overall, the research reviewed here suggests a general role of exogenous and endogenous adenosine signaling in normal penile erection. From this perspective, it is not surprising that impaired adenosine signaling is associated with ED, and excessive adenosine signaling is associated with priapism. Adenosine signaling represents a potentially important diagnostic and therapeutic target for the treatment of ED and priapism