Which Way is “Up” in Upgrading? Trajectories of Change in the Value Chain for South African Wine

Global Value Chain (GVC) analysis uses the concept of upgrading to highlight paths for developing country firms to “move up the value chain,” usually through the lenses of four categories—product, process, functional, and inter-sectoral upgrading. The implicit normative expectation is that these firms move toward producing higher value-added products and/or take on more sophisticated functions along a value chain. In this article, upgrading is approached more broadly as “reaching a better deal,” including a balance between rewards and risk. The case study of South African wine shows that better product quality, improved processes, and some functional upgrading have co-existed with processes of “downgrading,” higher risks, and limited rewards, especially in traditional export markets. A reflection on further conceptual development and directions for empirical research is also provided.     

OUTPUT FLUCTUATIONS PERSISTENCE: DO CYCLICAL SHOCKS MATTER?

The aim of this paper is to identify the different sources of persistence of output fluctuations. We propose an unobserved components model that allows us to decompose GDP series into a trend component and a cyclical component. We let the drift of the trend component switch between different regimes according to a first‐order Markov process. To calculate an appropriate p‐value for a test of linearity we propose a bootstrap procedure, which allows for general forms of heteroscedasticity. The performance of the bootstrap is checked by means of a Monte Carlo simulation. Our study concerns the USA. We find that cyclical shocks appear to play an important role on the observed persistence of output.     

相关行业上市公司政府补助对铁路公益性补贴的启示

针对航空运输、电信、石油等国家基础设施行业,通过分析这些行业上市公司的政府补助情况,在借鉴相关行业政府补助实践的基础上,提出建立铁路公益性运输发展基金,由中央政府和地方政府共同承担铁路公益性补贴责任的政策建议,同时认为铁路运输企业除争取公益性补贴外,还应争取税收优惠、专项补贴等其他补贴政策。     

WIC Participation and Relative Quality of Household Food Purchases: Evidence from FoodAPS

We examine the effect of the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC) on the quality of household food purchases using the National Household Food Acquisition and Purchase Survey (FoodAPS) and propensity score matching. A healthy purchasing index (HPI) is used to measure nutritional quality of household food purchases. WIC foods explain the improvement in quality of food purchases, not self‐selection of more nutrition‐conscious households into the program. The improvement in purchase quality was driven entirely by WIC participating households who redeemed WIC foods during the interview week. There was no significant difference between WIC participants who did not redeem WIC foods and eligible nonparticipants. In this sample, there is no evidence that lack of access to clinics has adverse effects on participation nor is there evidence that HPI depends on supermarket access. A supervised machine learning process supports our main conclusion on the importance of WIC foods.     

跨文化交际对应用型本科英语口语教学的影响

跨文化交际是指不同文化背景的人们之间的交际.外语教学的根本目的是实现跨文化交际,因此,应重视跨文化交际在口语能力教育上的重要作用,使学生了解语言与文化之间的关系,注重培养跨文化的意识,熟知中外文化异同与语言表达的形式特点,避免交际中出现语法应用正确却产生文化冲突的现象.     

考虑现实约束的不确定投资组合研究

作为实现财富增值保值的有效手段,投资组合引起了实务界和学术界的广泛关注。然而,以往研究大多忽略了金融市场的复杂性、外部因素的不确定性和历史数据的缺失性。为更准确刻画金融市场的现实状况、求解最优投资组合,本文引入不确定变量来描述证券收益率,进而构建包含交易成本、整手交易、流动性风险、交易上下限和行业分散化等现实约束的证券不确定投资组合模型;同时采用遗传算法进行计算,并代入模拟交易数据对比有现实约束和无现实约束投资组合模型的最优解。研究结果表明,引入现实约束条件后,最优投资组合发生了变化,期望收益率显著下降。上述研究结论带来的启示:对于证券投资者而言,在进行投资交易时,应充分考虑交易成本和不确定性风险,确保将投资风险限制在可控的范围之内;对于证券监管机构而言,应加强对证券市场的监督与管理,尤其是系统重要性机构,防范和化解流动性风险和不确定性风险。     

基于射频指纹技术的卫星信号个体识别方法

现有射频指纹识别研究主要集中于射频指纹产生及提取的通信机理,忽略了实际应用中信号采集数据的清洗筛分、识别算法模型的效率等工程性问题。为此,分析了卫星通信号的载波信息提取的原理与方法,并针对现有射频指纹方法的不足,围绕卫星信号识别领域,利用海量采集的射频指纹数据,深入研究基于自组织神经网络的射频指纹识别算法,提出了对应的算法模型,并与现有常见的无监督算法进行了比较。结果表明,所提方法可以取得更优的算法聚类效果和时间开销,可作为设计实现卫星频谱管理系统的基础。     

城市道路景观设计的几点意见

城市道路的景观设计既是城市的特色也是交通安全的重要影响因素,本文通过介绍山水东路以及金石南路两条道路的景观设计,就城市道路的交通组成研究了对景观设计的要求,城市道路景观对交通的影响,提出了城市道路景观设计与交通协调的内容与方法。结果表明,城市道路的景观设计能调节道路使用者的心理状态,对改善交通状况、减少交通事故的发生有重要作用。     

Calibrating spatial models of trade

Empirical spatial models of trade that are based on a mathematical programming specification often exhibit a large discrepancy between the equilibrium solution and the observed demand, supply and levels of trade flows among countries. This discrepancy may be due to several causes. Assuming, however, that a trade model is not misspecified – in the sense that behavior of the economic agents involved in the specific commodity markets has been included in the study and that the relevant policy instruments have been properly taken into account – the cause of discrepancy may be traced either to imprecision of unit transaction costs or to imprecision in the measurement of the demand and supply functions' parameters, or both. Policy assessments based on this type of imprecise models are distorted. This paper presents a methodology for calibrating mathematical programming spatial trade models of increasing complexity, from the one-commodity case to a multi-commodity model with asymmetric slope matrices of demand and supply functions. The proposed calibration procedure identifies corrections of imperfectly measured parameters. The calibrated models generate solutions that exactly reproduce quantities produced and consumed in all countries, as well as trade flows among all pairs of countries, observed in a given base year. Such models may then serve as a springboard for assessing the impact of various policy changes on economic agents in the countries under study.     

Abatement and Allocation in the Pilot Phase of the EU ETS

We use historical industrial emissions data to assess the level of abatement and over-allocation that took place across European countries during the pilot phase (2005–2007) of the European Union Emission Trading Scheme. Using a dynamic panel data model, we estimate the counter factual (business-as-usual) emissions scenario for EU member states. Comparing this baseline to allocated and verified emissions, we find that both over-allocation and abatement occurred, along with under-allocation and emissions inflation. Over the three trading years of the pilot phase we find over-allocation of approximately 280 million EUAs and total abatement of 247 Mt CO₂. However, we calculate that emissions inflation of approximately 73 Mt CO₂ also occurred, possibly due to uncertainty about future policy design features.