SARS疫情传播的时间序列分析

利用时间序列分析的思想[1～3],对北京市2003年4～6月的累计确诊SARS病例进行研究,获得了日增确诊病例的变化趋势方程,并用自回归模型AR(20)来拟合传播过程,经方差分析知模型效果高度显著,将预测值与实际值比较,结果比较理想.由此推定每个SARS病人可以直接造成他人感染的期限平均在20天左右.     

东盟为何深陷第三波新冠疫情

正自2021年4月以来,东盟各国相继出现了比以往更为严重的第三波新冠疫情。首先是东盟成员国中的"防疫优等生"越南沦陷,接着原本疫情不那么严重的柬埔寨、老挝、泰国也陷入防疫困境。其中越南累计确诊病例在3月31日还只有2603例,随后确诊病例呈几何级增加,日增确诊病例连续突破1000例、2000例、3000例、5000例。到8月5日,累计确诊病例已超过18万。柬埔寨累计确诊病例从4月1日的2440例增加到8月5日的8.02万例。     

北京市交通状况改善对策研究

北京市近几年的交通状况不容乐观，并有越发严重之势。本文应用管理学、经济学、心理学的相关理论对该问题的改善提出了一系列建议。为了能使北京市交通状况得到很好的改善，本文也提出了几点特殊强调。     

赤点石斑鱼室内水泥池养殖技术的初步研究

本文以赤点石斑鱼为对象，研究其在室内水泥池养殖过程中周年的日增重量、日摄食率和水温的关系；探讨赤点石斑鱼在室内水泥池的养殖管理技术。经４００天的饲养，鱼体成活率为８０．６％，平均日增重量０．４９克／尾，平均净增重１９５．５克／尾，平均日摄食率为２．０１％，饵料系数为８．８。因此认为，室内水泥池养殖赤点石斑鱼是可行的。     

一道高考数学建模题求解探讨

本文是根据2001年北京市春季高考一道数学建模题，运用数学优化理论和数学建模知识，探索出它的各种解答。     

不必谈蜱色变

最近，在北京市昌平区回龙观地区发现了一种叫蜱（音pi）的虫子，令人们谈之色变。此前，我国已经先后在天津、山东、河南、陕西、湖北、安徽、江苏等省市出现了部分人因被蜱叮咬而染病的病例，     

要做,就做最尖端的研究--访北京杂交小麦工程技术研究中心主任赵昌平

赵昌平 中共党员、博士、研究员。现任北京杂交小麦工程技术研究中心主任、首席专家。1994年入选北京市科技新星计划。主要研究领域为：光温敏二系杂交小麦研究、小麦高产栽培理论与技术研究。共主持或参加市级以上科研项目32项，获奖9项，其中作为主要贡献者，获北京市科技进步二等奖2项、三等奖1项、北京市农技推广一等奖1项、北京市自然科学基金二等奖1项。2000年，第一届杂交小麦国际研讨会在北京农业大学召开，一位年轻的中国科学家的主题演讲引起了各国专家的极大兴趣。按照大会规定，每位讲演者演讲完毕后，只有几分钟的答疑时间，…     

金炳镐教授简介

金炳镐，男，朝鲜族，1950年2月生于黑龙江延寿县，1974年毕业于中央民族学院（大学）政治系政治理论专业。现为中央民族大学马列主义学院院长、中国民族理论与民族政策研究院院长，教授、博士生导师、校学术委员会委员，中国民族理论学会副会长兼秘书长。在中央民族大学任教31年。1989年和1995年两次获得北京市优秀教师称号，破格晋升副教授、教授职称；1993年被评为享受政府特殊津贴的国家有突出贡献的专家；2002年获宝钢教育奖优秀教师奖，2003年被评为首届北京市高等学校教学名师、首届全国高等学校教学名师，成为全国民族院校首位国家级教学名师，2004年获首都五一劳动奖章，被评为首届国家民委有突出贡献的专家。     

重庆开埠后的商贸与长江区域整体市场的形成

重庆拥有广阔的商贸腹地，在西南具有强大的贸易辐射能力。重庆开埠后，商贸日增，与长江中下游各口岸城市的经济关系日益密切。依托长江航运，上下流通，东西呼应，形成长江区域整体市场。     

试论《儒林外史》中文士的说谎现象

吴敬梓以他独特的白描讽刺的笔法，描绘了封建盛世下知识分子说谎的种种可笑行径，其可谓“穷极士情态”。透过这些谎言，是整个社会的浮夸、追逐名利的大环境，这个大环境的背后则是束缚日增的科举制度。     

SARS传播规律函数的ELMAN神经网络逼近方法

提出了用ELMAN神经网络逼近传染病传播规律函数的方法,给出了影响传染病传播的影响因素简单近似的量化途径。用北京市和山西省的统计数据来验证该方法,验证结果表明,训练后的ELMAN神经网络能较准确的逼近传染病的传播规律函数,该方法对传染病的预测和控制有一定意义。     

The outbreak pattern of the SARS cases in Asia

The severe acute respiratory syndrome (SARS) caused tremendous damage to many Asia countries, especially China. The transmission process and outbreak pattern of SARS is still not well understood. This study aims to find a simple model to describe the outbreak pattern of SARS cases by using SARS case data commonly released by governments. The outbreak pattern of cumulative SARS cases is expected to be a logistic type because the infection will be slowed down due to the increasing control effort by people and/or due to depletion of susceptible individuals. The increase rate of SARS cases is expected to decrease with the cumulative SARS cases, as described by the traditional logistical model, which is widely used in population dynamic studies. The instantaneous rate of increases were significantly and negatively correlated with the cumulative SARS cases in mainland of China (including Beijing, Hebei, Tianjin, Shanxi,the Autonomous Region of Inner Mongolia) and Singapore. The basic reproduction number R0 in Asia ranged from 2.0 to 5.6 (except for Taiwan, China). The R0 of Hebei and Tianjin were much higher than that of Singapore, Hongkong, Beijing, Shanxi, Inner Mongolia, indicating SARS virus might have originated differently or new mutations occurred during transmission. We demonstrated that the outbreaks of SARS in many regions of Asia were wall described by the logistic model, and the control measures implemented by governments are effective. The maximum instantaneous rate of increase, basic reproductive number, and maximum cumulative SARS cases were also calculated by using the logistic model.     

Reovirus, isolated from SARS patients

Beijing has been severely affected by SARS, and SARS-associated coronavirus has been confirmed as its cause. However, clinical and experimental evidence implicates the possibility of co-infection. In this report, reovirus was isolated from throat swabs of SARS patients, including the first case in Beijing and her mother. Identification with the electron microscopy revealed the characteristic features of reovirus. 24 of 38 samples from other SARS cases were found to have serologic responses to the reovirus. Primers designed for reovirus have amplified several fragments of DNA, one of which was sequenced (S2 gene fragment), which indicates it as a unique reovirus (orthoreovirus). Preliminary animal experiment showed that inoculation of the reovirus in mice caused death with atypical pneumonia. Nevertheless, the association of reovirus with SARS outbreak requires to be further investigated.     

Control dynamics of severe acute respiratory syndrome transmission

Severe acute respiratory syndrome (SARS) is a serious disease with many puzzling features. We present a simple, dynamic model to assess the epidemic potential of SARS and the effectiveness of control measures. With this model, we analysed the SARS epidemic data in Beijing.The data fitting gives the basic case reproduction number of 2.16 leading to the outbreak, and the variation of the effective reproduction number reflecting the control effect. Noticeably, our study shows that the response time and the strength of control measures have significant effects on the scale of the outbreak and the lasting time of the epidemic.     

Exploring the epidemic transmission network of SARS in-out flow in mainland China

The changing spatiotemporal patterns of the individual susceptible-infected-symptomatic-treated-recovered epidemic process and the interactions of information/material flows between regions,along with the 2002-2003 Severe Acute Respiratory Syndrome(SARS) epidemiological investigation data in mainland China,including three typical locations of individuals(working unit/home address,onset location and reporting unit),are used to define the in-out flow of the SARS epidemic spread.Moreover,the input/output transmission networks of the SARS epidemic are built according to the definition of in-out flow.The spatiotemporal distribution of the SARS in-out flow,spatial distribution and temporal change of node characteristic parameters,and the structural characteristics of the SARS transmission networks are comprehensively and systematically explored.The results show that(1) Beijing and Guangdong had the highest risk of self-spread and output cases,and prevention/control measures directed toward self-spread cases in Beijing should have focused on the later period of the SARS epidemic;(2) the SARS transmission networks in mainland China had significant clustering characteristics,with two clustering areas of output cases centered in Beijing and Guangdong;(3) Guangdong was the original source of the SARS epidemic,and while the infected cases of most other provinces occurred mainly during the early period,there was no significant spread to the surrounding provinces;in contrast,although the input/output interactions between Beijing and the other provinces countrywide began during the mid-late epidemic period,SARS in Beijing showed a significant capacity for spatial spreading;(4) Guangdong had a significant range of spatial spreading throughout the entire epidemic period,while Beijing and its surrounding provinces formed a separate,significant range of high-risk spreading during the mid-late period;especially in late period,the influence range of Beijing’s neighboring provinces,such as Hebei,was even slightly larger than that of Beijing;and(5) the input network had a low-intensity spread capacity and middle-level influence range,while the output network had an extensive high-intensity spread capacity and influence range that covered almost the entire country,and this spread and influence indicated that significant clustering characteristics increased gradually.This analysis of the epidemic in-out flow and its corresponding transmission network helps reveal the potential spatiotemporal characteristics and evolvement mechanism of the SARS epidemic and provides more effective theoretical support for prevention and control measures.     

一种新的基于伪最近邻算法的降水预报方法

分析北京地区日降雨量资料,相较于其他降雨事件,大雨或暴雨事件发生的次数较少,因此该地区的降水量预报属于样本不均衡问题。在样本不平衡的情况下,K最近邻(PNN)算法的分类误差率将会大大提高,这也就使传统的基于K最近邻算法的降水量预报方法的应用受到了限制。针对北京地区降水量预报这一样本不均衡问题,应用伪最近邻算法构建了北京市的降水量预报模型。该方法利用北京地区日降雨量资料和美国国家环境预报中心全球格点资料,将降雨量作为类,将美国国家环境预报中心全球格点资料的各种因子场作为天气样本特征,通过决策规则实现最优分类。利用提出的降水预报模型对北京地区2010年6~8月进行了24 h降水预报,实验结果表明,提出的预报方法对于降水等级预报的预报准确率以及晴雨预报的TS评分、正样本概括率和漏报率均优于传统的K最近邻预报方法,该方法具有较好的预报效果。     

基于分形理论的北京城市形态结构遥感分析

 城市形态结构分析对北京市的长远规划具有重要意义,运用分形思想规划城市对人居环境的改良和人地关系的协调也有着重要意义。本研究基于分形理论,运用GIS空间分析等方法,对北京城市形态结构和变化进行了定量的分析与评价,预测了北京市未来城市发展范围。利用TM遥感影像监督分类,提取1992、1999和2006年北京市建筑用地面积,以城市中心为圆心,取几十个半径递增的同心圆进行剪裁,得出各个同心圆内的城市建筑用地面积。通过反复试验确定双标度区并得到城市建筑用地面积折线图,并对面积进行基于乘幂关系的函数拟合,拟合优度R2≥0.995。并得到分维数D以及北京市范围及其变化。在得到这些数据后,进行了深入的分析以解释这些现象,同时对北京市与其他大城市的城市形态进行对比。最后,对北京市的城市建筑用地的未来发展以及可能出现的情况做出预测。     

北京市SARS数学模型的建立与拟合

SARS对中国社会的发展产生了重大影响，本人经典的SIR模型为理论基础，以2003年4月21日至6月23日有关SARS的数据为参考资料，着重从教学的角度对SARS疫情进行了分析和拟合。结果表明，SIR模型能近似地描述SARS疫情的发展和变化。     

SARS传播模型的探讨

首先以传统的Logistic模型和SEIR模型分析了SARS传播的一般规律,并以北京地区2003年4月20日到6月23日有关SARS数据为参考资料,对北京地区SARS疫情高峰期和最终感染人数作出估计,由此得到SARS传播服从Logistic模型和SEIR模型,其次,在此基础上分析了两物种间的疾病传播规律,建立了两物种间疾病传播的SEIR模型。     

把密云建设成为北京的旅游卫星城

在简要介绍卫星城理论的基础上，分析了北京市卫星城的发展状况。根据密云的发展条件，结合北京城市总体规划的要求，指出密云宜发展成为北京的旅游卫星城提出了建设密云旅游卫星城的７项规划措施：１）保护流经密云镇的河流上有水；２）城镇绿化要成体系；３）布置城镇雕塑和喷泉；４）开辟旅游商业街；５）接纳北京拆迁的古建；６）增加康体休闲设施；７）吸引高技术企业投资办厂。