Estimating prevalence using composites

We are interested in estimating the fraction of a population that possesses a certain trait, such as the presence of a chemical contaminant in a lake. A composite sample drawn from a population has the trait in question whenever one or more of the individual samples making up the composite has the trait. Let the true fraction of the population that is contaminated be p. Classical estimators of p, such as the MLE and the jackknife, have been shown to be biased. In this study, we introduce a new shrinking estimator which can be used when doing composite sampling. The properties of this estimator are investigated and compared with those of the MLE and the jackknife.     

Human performance in polar environments

An overview of the physical, psychological, social, and coping aspects of living and working in polar regions is presented, assessing findings from both expedition teams and work groups. A personal narrative describing the experiences of a polar expeditioner is interspersed in relevant sections to provide a deeper understanding of the challenges of performing in an extreme environment. The application of findings from polar environments as an analog for space missions is discussed. We conclude that further research is needed on the integration of psychosocial and neurobehavioral adaptation. Furthermore, it is important to consider both the positive as well as negative features of living and working in polar and other extreme environments, and develop training strategies and countermeasure tools to optimize performance in these conditions.     

Effect of the effective stress coefficient and sorption-induced strain on the evolution of coal permeability: Experimental observations

Permeability is one of the most important parameters for CO₂ injection in coal to enhance coalbed methane recovery. Laboratory characterization of coal permeability provides useful information for in situ permeability behavior of coal seams when adsorbing gases such as CO₂ are injected. In this study, a series of experiments have been conducted for coal samples using both non-adsorbing and adsorbing gases at various confining stresses and pore pressures. Our observations have showed that even under controlled stress conditions, coal permeability decreases with respect to pore pressure during the injection of adsorbing gases. In order to find out the causes of permeability decrease for adsorbing gases, a non-adsorbing gas (helium) is used to determine the effective stress coefficient. In these experiments using helium, the impact of gas sorption can be neglected and any permeability reduction is considered as due to the variation in the effective stress, which is controlled by the effective stress coefficient. The results show that the effective stress coefficient is pore pressure dependent and less than unity for the coal samples studied. The permeability reduction from helium experiments is then used to calibrate the subsequent flow-through experiments using adsorbing gases, CH₄ and CO₂. Through this calibration, the sole effect of sorption-induced strain on permeability change is obtained for these adsorbing gas flow-through experiments. In this paper, experimental results and analyses are reported including how the impact of effective stress coefficient is separated from that of the sorption-induced strain on the evolution of coal permeability.     

精明收缩理念下的资源型城市生态安全格局修复实施路径设计——以冷水江锡矿山为例

资源型城市通常面临环境恶化、景观破碎、生态流动性受阻等问题,生态系统亟需修复;同时,其作为收缩城市的重要类型之一,人口外流、经济衰退导致大量用地废弃与房屋空置,低效的用地亟需调整。以冷水江市锡矿山为例,本文将传统生态安全格局修复范式引入到收缩城市空间治理工作中,以电流密度计算结果得到的关键生态流路径和障碍点作为分期修复的依据,结合实际土地利用情况制定分区分期收缩计划,对关键障碍点进行再利用设计策略思考并检验修复效果。将生态安全格局分析和资源型城市空间收缩治理相结合,整合“生态分析—政策研究—规划设计”探索符合资源枯竭城市分步式生态修复路径,及其土地利用和空间形态分期、有序地实现精明收缩和地理设计方法。     

寒旱区湖泊浮游植物特征及其对营养状态的指示作用

为揭示内蒙古典型湖泊浮游植物群落特征及其对营养状态的响应,于2019年和2020年7月对呼伦湖,岱海,乌梁素海和居延海浮游植物和水质理化指标进行取样调查.结果显示,呼伦湖,岱海,乌梁素海和居延海分别鉴定出浮游植物101种,44种,125种和42种,绿藻门,硅藻门和蓝藻门是其优势门类.调查期间4个湖泊浮游植物的总丰度分别为5.71×10⁵,0.18×10⁵,3.45×10⁵和6.96×10⁵cells/L;根据优势度分析,居延海优势种最少为6种,其他湖泊优势种都在10种以上;CCA分析表明,综合营养指数(TLI),水温(T),总溶解性固体(TDS),氨氮(NH₄⁺-N),盐度(SAL),pH值(P<0.01)是浮游植物优势种的主要影响因子.4个湖泊的浮游植物Shannon-Wiener多样性指数(H′),丰富度(D),均匀度(J)指数均值分别为1.4,0.38和2.79(呼伦湖),2.28,0.87和1.42(岱海),2.99,0.74和4.46(乌梁...     

基于PM2.5监测点空间聚类的关中五市空气污染区域识别

区域大气污染联防联控是空气质量管理的重要举措,准确识别空气污染区域对联防联控措施有重大意义.本研究采用陕西省关中五市（西安、咸阳、宝鸡、渭南、铜川）国控和省控全部90个监测点的小时级PM_2.5浓度监测数据,运用邻接约束层次聚类方法对监测点进行空间聚类,并利用泰森多边形和曲线平滑等技术识别空气污染区域.结果表明：1关中五市空气污染存在跨行政区划的区域性特征,本研究识别出2个特征显著不同的空气污染区域（区域1和区域2）;2区域2的PM_2.5浓度在统计上显著高于区域1,且重度和严重污染天数也显著高于区域1;3空气污染区域与地形特征关系密切,区域1均为高海拔区县,而区域2均为低海拔区县.依据空气污染区域的不同特征,在区域污染程度存在显著差异时,应当采取不同等级的污染防控措施,以减少对关中五市43%的国土面积、23个区县、639万人及3355亿元国内生产总值的影响,使区域空气污染防控措施更加科学、合理与精准.同时,空气污染区域的划分对缺失数据和不同空气污染等级表现稳健.     

中国严寒地区住宅建筑室内细菌气溶胶污染特征及传播规律

实测严寒地区住宅建筑细菌气溶胶组分及来源,并结合微生物生长繁殖衰亡模型和数值模拟技术开展细菌气溶胶传播特性研究.结果表明,中国严寒地区住宅建筑室内的主要优势菌群为拟杆菌门（Bacteroidetes）、厚壁菌门（Firmicutes）、变形菌门（Proteobacteria）.而细菌的来源分析显示,其主要来源为粪便、土壤、极端环境、植物、水源和腐败有机物等.由于冬季人员室内活动时间较长,其中粪便来源占比偏高.细菌在室内的传播规律研究表明,在室内环境中细菌气溶胶的浓度分布与房间的结构、湍流形式和粒子重力场有关.随着房间高度的降低,室内流场越复杂.模拟分析表明室内90％的细菌气溶胶颗粒在50s内逃逸出,且随着房间高度的降低细菌气溶胶浓度逐渐降低而范围更广.室内通风有阻碍细菌气溶胶在室内积聚,稀释污染浓度的作用.     

The Great East Japan Earthquake,tsunami, and nuclear meltdown: towards the (re)construction of a safe,sustainable, and compassionate society in Japan's shrinking regions

Japan's rural regions have been shrinking for the entire post-war period, and successive efforts to revitalise rural society have failed. This article examines whether the Great East Japan Earthquake and tsunami, and the subsequent meltdown at the Fukushima Daiichi nuclear power plant, present the Japanese state and society with a watershed opportunity to rethink regional revitalisation and national energy procurement strategies. The article begins by summarising the events of March and April 2011, examines possible approaches to the reconstruction of communities in the Tōhoku region, and critiques problems of governance in post-war Japan that the disaster reveals. It concludes by pulling together the information and analysis presented into a discussion of the prospects for achieving the three-point vision for a safe, sustainable, and compassionate society that Prime Minister Naoto Kan set the Reconstruction Design Council.     

A bottom-up approach towards the assessment of ecological footprints and biocapacity

The concept of ecological footprint (EF) assessment embeds into the broader concept of sustainable development, relating directly to quality of life and maintaining the natural constraints of the global ecosystem. EFs relate to the balance between the Earth's biocapacity and consumption, measured as land equivalence in global hectares per capita. The majority of studies relating to EF assessments have adopted a top-down methodology in order to assess national and regional EFs. Furthermore, these studies are mainly based upon national accounts of input, output and trade; information which is readily available for most countries, and the EFs usually require an assessment of equivalent land area per capita to maintain the current levels of consumption. Since its inception in the mid-1990s, the EF methodology has been refined and has been widely adopted by many countries and governments as a tool to measure biocapacity, or, the consumption of resources. In this paper, we present a bottom-up methodology to measure the EF of a rural region (near Chennai) in southern India. Advantages and limitations of this approach are then discussed through comparisons with regional and national assessments.     

Analysis of the Difference of the Basic Pension by Regions

Abstract

Nowadays, the disparity of the basic pension in local regions of China can be described as follows: the low level of the unification of the basic pension systems, the large disparity of the level of the basic pension, and unfairness of the enterprises' payment for the basic pension in different local regions in China. These have already brought many negative influences, which have greatly held back the development of the society and national economy. We should build the basic pension system in all local regions of China as a whole, which can cover all people and decrease the disparity in different local regions in China.