Critical branching random walks, branching capacity and branching interlacements

This thesis concerns critical branching random walks. We focus on supercritical (d ≥ 5 or higher) and critical (d=4) dimensions. In this thesis, we extend the potential theory for random walk to critical branching random walk. In supercritical dimensions, we introduce branching capacity for every finite subset of ℤ^d and construct its connections with critical branching random walk through the following three perspectives. 1. The visiting probability of a finite set by a critical branching random walk starting far away; 2. Branching recurrence and branching transience; 3. Local limit of branching random walk in torus conditioned on the total size. Moreover, we establish the model which we call 'branching interlacements' as the local limit of branching random walk in torus conditioned on the total size. In the critical dimension, we also construct some parallel results. On the one hand, we give the asymptotics of visiting a finite set and the convergence of the conditional hitting point. On the other hand, we establish the asymptotics of the range of a branching random walk conditioned on the total size. Also in this thesis, we analyze a small game which we call the Majority-Markov game and give an optimal strategy.Science, Faculty ofMathematics, Department ofGraduat

Research on Liquid CO

Due to the low temperature and clean gas, liquid CO2 phase transition ejection technology has outstanding advantages such as high versatility, low launch cost, and environmental friendliness, which will open up a new research field for the development of missile launch technology. Through the study of phase transition characteristics of liquid CO2 in this paper, a mathematical model of internal ballistics of the liquid CO2 phase transition ejection power system is established. And through simulation calculation, the launching parameters such as the pressure in the launcher, the velocity and acceleration of the missile are obtained, and they is compared with the experiment data to verify the validity of the model

MicroRNA-145-Mediated KDM6A Downregulation Enhances Neural Repair after Spinal Cord Injury via the NOTCH2/Abcb1a Axis

Spinal cord injury (SCI) causes a significant physical, emotional, social, and economic burden to millions of people. MicroRNAs are known players in the regulatory circuitry of the neural repair in SCI. However, most microRNAs remain uncharacterized. Here, we demonstrate the neuroprotection of microRNA-145 (miR-145) after SCI in vivo and in vitro. In silico analysis predicted the target gene KDM6A of miR-145. The rat SCI model was developed by weight drop, and lipopolysaccharide- (LPS-) induced PC12 cell inflammatory injury model was also established. We manipulated the expression of miR-145 and/or KDM6A both in vivo and in vitro to explain their roles in rat neurological functional recovery as well as PC12 cell activities and inflammation. Furthermore, we delineated the mechanistic involvement of NOTCH2 and Abcb1a in the neuroprotection of miR-145. According to the results, miR-145 was poorly expressed and KDM6A was highly expressed in the spinal cord tissue of the SCI rat model and LPS-induced PC12 cells. Overexpression of miR-145 protects PC12 cells from LPS-induced cell damage and expedites neurological functional recovery of SCI in rats. miR-145 was validated to target and downregulate the demethylase KDM6A expression, thus abrogating the expression of Abcb1a by promoting the methylation of NOTCH2. Additionally, in vivo findings verified that miR-145 expedites neuroprotection after SCI by regulating the KDM6A/NOTCH2/Abcb1a axis. Taken together, miR-145 confers neuroprotective effects and enhances neural repair after SCI through the KDM6A-mediated NOTCH2/Abcb1a axis

Simulating spatial distribution and varying patterns of population in Urumqi, China - art. no. 67900A

Taking Urumqi as a case, a simulation of urban population spatial distribution is proposed based on urban land use and population statistical data using GIS, and population spatial distribution patterns are analyzed by the raster population surface. As a result, generating raster population spatial distribution surface is more accurate and natural than the traditional choropleth map of population density in Urumqi. Concerning the population spatial distribution of Urumqi, the population density declines from south to north and the population distribution mainly presents "T-type", the population distribution presents polycentric agglomeration and the population distribution of the districts shows different features. The population density varies significantly with the increase of the distance from CBD. Finally, this paper finds that the development history of districts, terrain and traffic road are main factors influencing Urumqi's population distribution. This paper tries to provide more accurate data of population distribution for the plan and management of urban land, traffic and public facilities in order to enrich the researches of urban population distribution

基于气候、地貌、生态系统的景观分类体系——以新疆地区为例/Landscape classification system based on climate, landform, ecosystem: a case study of Xinjiang area[J]

景观分类是景观生态学研究的重要内容之一,既是景观结构与功能研究的基础,又是景观规划、管理等应用研究的前提条件,目前尚没有具有适普性的景观分类体系.提出了景观生态学的一种发生学分类方法,即景观带——基于气候的一级指标(温度带,反映纬度地带性)、景观区——基于干旱指数的二级指标(干湿区,反映经度地带性)、景观类——基于垂直地貌的三级指标(山地和平原,反映垂直地带性)、景观型——基于自然生态系统和人工生态系统的四级指标(反映自然生态系统特征和人类活动)的四级景观分类体系.并利用该体系对新疆地区进行了景观分类,将新疆地区划分为3个景观带、4个景观区、2个景观类、11个景观型.该分类体系与地理景观学派除在自然景观分类系统不同之外,将人工景观指标引入了景观发生学分类.为研究景观分类提供了一种思路和方法,这种分类方法对新疆地区景观的成因、景观演变规律、景观恢复与修复标准等提供了背景参考