The equity impacts of bus rapid transit: A review of the evidence and implications for sustainable transport

The paper offers an analysis of empirical evidence on the equity impacts of operational Bus Rapid Transit (BRT) systems in the Global South. The focus is on vertical equity, i.e. whether BRT systems achieve progressive benefits for poorer segments of the population. Findings from Africa, Asia, and Latin America all suggest that BRT does offer significant benefits to low-income groups, in terms of travel time and cost savings, access enhancement, and safety and health benefits. However benefits are often skewed toward medium-income users and thus less progressive than they might be. Two primary reasons for this are insufficient spatial coverage and inappropriate fare policies. While many features of BRT potentially allow it to deliver pro-poor outcomes, such outcomes only materialize if BRT implementers pay specific and sustained attention to equity. The paper identifies key issues that need to be addressed to steer BRT implementation toward more socially sustainable outcomes—including better integration with other transit, paratransit, and nonmotorized transport services, and with the housing sector.     

An Exploratory analysis of flight delay propagation in China

Delay propagation is the flight departure delay caused by the arrival delay of pre-segment flight. Chinese airline market has suffered very poor on-time performance (OTP) in recent years. It is, however, unclear whether delay propagation prevails as one major source for such problem. This study first aims to empirically quantify delay propagation in the Chinese airline market. Specifically, we shed light on heterogenous levels of delay propagations across different airports and airlines. Then, the distinct delay propagation patterns in China are also discussed and compared with other developed airline markets (e.g., the US and Europe). Our estimation is based on OTP data for over 12 million Chinese flights covering the 2015–2017 period. Specifically, it is found that 10 min arrival delay of pre-segment flight within 1 hr before the departure lead to an average of 7.49 mins delay propagation for subsequent departure flight. Arrival delay of earlier pre-segments (1–2 and 2–3 hr before the departure) leads to much less delay propagation, due to longer ground buffer. Chinese airlines arrange longer ground and flight buffer than that of the US airlines to prevent the delay propagation from accumulating along the subsequent flights in a day. Thus, unlike the US market, delay propagation is not the major reason for poor OTP in China. In addition, delay propagation is less prevailing at the Chinese hub airport. This is because China has relied on point-to-point network, which does not require sophisticated schedule coordination. And the local passengers at these Chinese hub airports have higher time value such that the Chinese airlines also try to improve OTP at these hub airports to better serve these lucrative but time-sensitive local passengers. Unlike the European LCCs, Spring Airlines, the largest low-cost carrier (LCC) in China, outperforms major full-service carriers (FSCs) in controlling delay propagation. This finding may also apply to other Northeast Asian LCCs sharing common operational characteristics as Spring Airlines. Last, we find that airlines purposely tolerate moderate departure delays of up to 15 min, which is the threshold that defines delays, no matter whether the pre-segment flight arrives late or on-time. The relevant policy and managerial implications are also discussed.     

苹果中腐霉利残留快检测定及方法评估

本研究以阿克苏苹果样品中腐霉利的残留为研究对象,采用行业标准《蔬菜和水果中有机磷、有机氯、拟除虫菊酯和氨基甲酸酯类农药多残留的测定》(NY/T 761—2008)为参比方法,分别选取3家快检试剂盒测定苹果样品中添加的不同浓度腐霉利标品,根据《食品快速检测方法评价技术规范》对其快检适用性进行评估.结果显示,试剂盒A与试剂盒C在0.3 mg·kg-1浓度以上呈阳性结果,灵敏度为75％、特异性为100％、假阴性率为25％、假阳性率为0;试剂盒B在0.1 mg·kg-1以上呈阳性结果,其灵敏度为100％、特异性为50％、假阴性率为0、假阳性率为50％;3家试剂盒的显著性差异均为83.33％、相对准确度为8.1％.所选试剂盒适用于苹果中腐霉利残留量的快速筛查.     

快速城镇化进程中保障失地农民就业的政府角色定位--基于罗尔斯的正义原则分析

失地农民这个特殊群体是伴随我国快速城镇化的发展政策产生的,保障这个群体的就业,使这个社会“最不利者”群体享有自由和平等,政府理应充当重要的角色。本文基于罗尔斯正义原则的启示,从公平时序性角度出发,认为政府对失地农民应充当三种角色,即起点公平的支持者、过程公平的引导者和协调者、结果公平的保障者。     

视距传播中地面起伏对传播中值衰减的影响

电波在以视距传播方式进行传播时,在低空大气层中还要受到地面的影响。文中具体分析了视距传播下几种传播模型中地面起伏对电波传播衰减中值的影响,并进行了相应的计算,最后给出相应地面起伏度与传播衰减中值之间的关系。     

我国橡胶产业发展现状及存在的问题

本文介绍了我国橡胶市场的发展状况。指出我国像胶产业发展较快，但也存在许多实际问题，比如品牌培育不力、严重依赖进口等，同时还指出我国橡胶市场发展前景广阔。最后提出了促进我国橡胶产业发展的几点策略。     

Multiple Temporalities of Policy Circulation: Gradual,Repetitive and Delayed Processes of BRT Adoption in South African Cities

In 2006, bus rapid transit (BRT) swept across South African cities. Within three years of learning of the Bogotá model of BRT, Johannesburg's Rea Vaya opened, followed shortly by Cape Town's MyCiTi, while several other cities are at various stages of planning and implementation. This article traces the circulation of BRT across the South African urban context to expose the multiple and varied temporalities through which BRT came to appear as the only available solution. These earlier encounters, which include the first published discussion of BRT in South Africa in a 1973 conference report, study visits to Curitiba in the 1990s and a failed attempt to implement a Bogotá‐style BRT system in Cape Town in 2003, were instrumental in creating a fertile ground for later adoption practices. While it may appear as if circulated policies shorten the gestation time from policy introduction to policy adoption, these repeated attempts to implement circulated innovations ensure that the turnover only seems accelerated. This article unravels the story of BRT adoption, departing from the theoretical discussions of the policy circulation process as a rapid phenomenon, instead demonstrating that it is gradual, repetitive and at times delayed.     

袁店一矿主井箕斗装载硐室优化施工工艺快速施工

介绍装载硐室通过优化施工工艺,精心组织、科学管理,采用正台阶掘进法分上、下台阶施工装载硐室,总结了一套科学、实效的施工工艺,从而保证快速施工。     

论加强地勘单位人才队伍建设

随着地勘业务的不断拓展,笔者深深感到人才已是制约地勘单位发展的重要瓶颈,必须创新机制,大力实施"人才兴院"战略,最大限度发挥人才作用,才能保持单位地勘经济的快速发展。     

快速分析萤石中氟化钙、碳酸钙的探讨

萤石的经典分析方法是将碳酸钙和氟化钙分离后,在用滴定法分别进行滴定分析,这种分析方法较为准确,但周期长、效率差、多次滴定易产生误差,无法满足快速大量测定样品的要求。本文探讨通过采用滴定-原子吸收法相结合方式测定萤石中氟化钙、碳酸钙的含量,可在大幅缩短测定时间的同时避免二次滴定产生的误差提升结果准确度,并可用于满足大量萤石样品的分析需求。