The scope and scale of the informal food economy of South African urban residential townships: Results of a small-area micro-enterprise census

Growing urbanisation in South Africa is reflected in burgeoning Working class and informal township settlements on the fringes of its major towns and cities. Paired with this is an increasing reliance on cash as the primary means of economic transaction, which has in turn stimulated the growth of micro-enterprise business activities within the township context. This article discusses the findings of an eight-township small-area census which occurred between 2010 and 2013 in Cape Town, Johannesburg, Ekurhuleni and Durban townships representing 250 000 residents. The researchers were able to establish the scope and scale of informal food and drink retailing in these localities. Of the 10 049 micro-enterprises located in the study, some 3966 (or 39% of the total) trade in food. These include enterprises in primary production, fresh produce retailing, grocery retailing from house and spaza shops, and informal foodservice enterprises. Food is the basis for much township informal business and plays an important role in making food increasingly affordable and locally accessible, and in creating cash employment. The article builds on the knowledge base of the township informal economy role in bolstering food security needs for the marginalised.     

后疫情下休闲体育产业高质量发展的推进策略

新冠疫情以来,人们的健康意识觉醒,体育产业越来越受重视,本文通过对疫情期间体育产业受到的影响进行分析,从体育消费、体育产品中小企业、体育赛事几个方面阐述了疫情以来体育产业受到的阻碍。凡事都有两面性,疫情也为体育产业带来了新的机遇,"线上+线下"融合、新兴产业的崛起、人们健康意识的加强都因为疫情带来了新的发展动力。在后疫情时代,政府应该推出新的政策与措施鼓励体育产业发展,市场则应该抓住机遇实现体育产业的供给侧改革,通过与新兴产业、互联网等的结合,推动体育产业的转型升级。     

经济新常态下煤炭企业发展战略研究

着眼于当前我国煤炭企业的新环境,我们要转变视角,致力于探索推动我国煤炭行业发展的新途径和新方法,为了更好地保护矿工的合法权益,保障煤炭行业的可持续发展,煤炭企业需要引进一些创新性技术和先进管理理念。论文主要基于关心矿工生命安全和煤炭企业安全发展的角度,对目前我国煤炭企业的发展提出一些思考和策略。     

基于GM(1,1)模型的造纸业上市公司财务研究——以冠豪高新为例

财务风险是企业调整发展战略、提升管理水平的重要参考指标之一。财务风险预测模型的建立能够预测企业在中短期内的财务风险,为企业敲响警钟。以造纸业上市公司冠豪高新为例,选取近五年财务杠杆系数为风险指标,建立GM(1,1)风险预测模型,结果显示该公司短期内财务风险呈下降趋势,调查发现这主要得益于产品成本的降低以及营销策略的改变。     

Quantifying the impact of the COVID-19 pandemic on US airline stock prices

This paper uses data at the trading day frequency and the method of local projections to quantify the dynamic responses of U.S. airline stock prices to a COVID-19 shock. We show that airline stock prices decline immediately by 0.1 percentage point in response to a 1% COVID-19 shock. In addition, the effect of the shock persists beyond the day on which it occurs, with most airline stock prices falling by as much as 0.6 percentage points after fifteen days. This negative response of airline stock prices to a COVID-19 shock is not explained by a COVID-19-induced increase in airlines’ variable costs, but rather by a COVID-19-induced decrease in air travel, which, in turn decreases revenues, profitability, and stock prices of U.S. airlines.     

Estimating yield curves of the U.S. Treasury securities: An interpolation approach

Following the approach of interpolation, this paper proposes the multiple exponential decay model to fit yield curves for both the U.S. TIPS market and the conventional Treasury security market. Several estimation methods, including the unconstrained/constrained nonlinear minimization, quadratic programming, and the iterative linear least squares, are applied to estimate the unknown parameters according to different curve‐fitting purposes. Comparisons between the proposed model and the alternatives show that the multiple exponential decay successfully (1) adapts to a variety of shapes associated with yield curves, (2) (partially) keeps in line with the economic interpretations of Nelson–Siegel summarized by Diebold and Li ( 2006 ), and (3) dominates the competing models in curve‐fitting performance measured by mean fitted‐price errors over the sample period. In addition, the exact specification of a nonparametric interpolation model is pinned down by applying three statistical tools, which enable us to jointly take into account validity, optimality, and parsimoniousness of the proposed model.     

Overcoming the “Solow paradox”: Tariff reduction and productivity growth of Chinese ICT firms

This paper examines the phenomenon of the “Solow paradox” in China using the Annual Survey of Industrial Production database and the China Customs Records dataset from 1998 to 2007. We find that China likely fell into the Solow paradox in the period 1998–2002, but the total factor productivity of information and communication technology (ICT) enterprises has achieved rapid growth since 2003. Accession to the World Trade Organization is the key reason for China to overcome the Solow paradox, that is, input tariff reduction significantly promoted the productivity of ICT firms. A series of validity and robustness checks confirmed the results. Mechanism analysis shows that input liberalization promotes the productivity of ICT firms through optimizing factor structure, importing more and high-quality inputs, and increasing research and development investment. The conclusions provide strong empirical evidence for developing countries to overcome the Solow paradox through trade liberalization.     

可食性小麦蛋白膜的研究

本文介绍了小麦蛋白及其成膜特性,总结了国内外可食性蛋白膜的研究现状,提出了可食性小麦蛋白膜的研究方案,并对膜的安全性及其应用作了展望。