浅析高职公共英语教学中项目教学法的应用

项目教学法是英语教学中常用的一种教学方法。该教学方法以学生为中心,旨在培养高素质、复合型的人才,切实提升高职毕业学生的英语应用水平。笔者结合多年来一线教学的经验和案例,对如何更好的实施项目教学法进行了探讨,分析了项目教学法在高职英语教学中实际应用的方法。     

Does tax policy affect credit spreads? Evidence from the US and UK

This paper studies how exogenous tax changes affect credit market conditions in the US and UK. Using both structural VAR and structural factor-augmented VAR (FAVAR) model, we find that tax-policy shocks have significant effects on the credit spread. Specifically, the credit spread responds first positively and then negatively to an exogenous tax increase in the two countries. Moreover, the impulse responses of the credit spread to tax-policy shocks do not always accord well with the impulse responses of the output. This indicates that there are channels of tax policy transmission to the credit spread other than through its impact on the business cycle.     

An optimal stochastic control framework for determining the cost of hedging of variable annuities

An implicit partial differential equation (PDE) method is used to determine the cost of hedging for a Guaranteed Lifelong Withdrawal Benefit (GLWB) variable annuity contract. In the basic setting, the underlying risky asset is assumed to evolve according to geometric Brownian motion, but this is generalised to the case of a Markov regime switching process. A similarity transformation is used to reduce a pricing problem with K regimes to the solution of K coupled one dimensional PDEs, resulting in a considerable gain in computational efficiency. The methodology developed is flexible in the sense that it can calculate the cost of hedging for a variety of different withdrawal strategies by investors. Cases considered here include both optimal withdrawal strategies (i.e. strategies which generate the highest possible cost of hedging for the insurer) and sub-optimal withdrawal strategies in which the policy holder׳s decisions depend on the moneyness of the embedded options. Numerical results are presented which demonstrate the sensitivity of the cost of hedging (given the withdrawal specification) to various economic and contractual assumptions.     

Toward a food secure future: Ensuring food security for sustainable human development in Sub-Saharan Africa

Food security remains a top development priority and global concern. It is enshrined in the 2030 Agenda for Sustainable Development in Sustainable Development Goal two. Food security is also a core component of the human development and capability paradigm, since food access and entitlements are critical for reinforcing essential human capabilities. In introducing this special issue, this paper argues that agriculture is central to improving food security and reducing poverty in Africa. It suggests that realizing the potential of agriculture in Africa requires rapid increases in land productivity and increases in agricultural yields. A science-based approach that integrates gender and sustainability is critical to meet this goal, through the design and implementation of policies that improve the availability farm inputs and farm technology. The paper concludes by introducing the papers in this special issue.     

Health matters: the social impacts of street-involved youth’s participation in a structured leisure programme

In this ethnographically informed study, we used a Foucauldian approach to examine the social impacts of street-involved youth’s participation in a structured leisure programme. Our findings suggest that structured leisure activities help to facilitate social ties between the youth participants as well as the youth and programme staff/volunteers. Nevertheless, we found that structured leisure does not necessarily assist in the formation of relationships between street-involved youth and members of the mainstream community outside of the programme. We show how the ways the youth took up dominant discourses concerning street-involved youth and engaged with technologies of the self-influenced their social relationships and their ties to the community. These findings complicate our understanding of structured leisure’s potential benefits for street-involved youth.     

A network approach for assembling and linking input–output models

Input–output (IO) models, describing trade between different sectors and regions, are widely used to study the environmental repercussions of human activities. A frequent challenge in assembling an IO model or linking several such models is the absence of flow data with the same level of detail for all components. Such problems can be addressed using proportional allocation, which is a form of algebraic transformations. In this paper, we propose a novel approach whereby the IO system is viewed as a network, the topology of which is transformed with the addition of virtual nodes so that available empirical flow data can be mapped directly to existing links, with no additional estimation required, and no impact on results. As IO systems become increasingly disaggregated, and coupled to adjacent databases and models, the adaptability of IO frameworks becomes increasingly important. We show that topological transformations also offer large advantages in terms of transparency, modularity and increasingly importantly for global IO models, efficiency. We illustrate the results in the context of trade linking, multi-scale integration and other applications.     

A quantile-boosting approach to forecasting gold returns

We use a quantile-boosting approach to compute out-of-sample forecasts of gold returns. The approach accounts for model uncertainty and model instability, and it allows forecasts to be computed under asymmetric loss functions. Different asymmetric loss functions represent different types of investors (optimists versus pessimists). We document how the performance of a simple trading rule varies across investor types.     

Analysing mobility biographies with the life course calendar: a retrospective survey methodology for longitudinal data collection

Transportation research is in need of longitudinal data to better understand travel behaviour. This paper describes a new survey method to collect longitudinal data, called the life course calendar. We discuss the need for and the uses of this instrument with reference to specific case study material and explore to what extent the life course calendar is suitable for the study of individual life courses and travel behaviour. In the first part of this article we give an overview of current research on the causal relationships between certain life events and travel behaviour. Based on the outcomes of the literature review we analyse life course calendars of 646 respondents. Considering the explorative character of our case study material the results are quite promising. Most notably information on car purchases, on relocations, and changes of the work place has been well recorded which indicates that the life course calendar is suited for the study of changes of spatial contexts and accessibility. The data analysis has provided initial results on the distribution of key events over the life course and on the relation of such events to changes in travel behaviour. Significant effects were found for key events such as relocation, change of job, birth of first child, separation/divorce, moving in with partner and retirement. The life course calendar can be advantageous, especially if it is employed to supplement extensive panel studies.     

煤电企业生命周期阶段界定的方法研究

煤电企业具有特定的生命周期轨迹,从企业生命周期角度来研究煤电企业具有较高的理论和现实意义。基于企业生命周期理论,选取了反映公司盈利能力、成长能力、营运能力、偿债能力和现金能力五方面的指标来建立了界定企业生命周期阶段的指标体系。选用2007年-2013年郑州煤电股份有限公司的季度财务数据,运用AHP法和熵权法分别计算企业在每个阶段和综合的财务指标权重,再运用判别分法以距离小为判别标准判断出郑州煤电股份有限公司属于生命周期阶段的成长期。     

修正费用现值法在煤矿辅助运输方案选择中的应用

煤矿辅助运输系统受到很多因素影响,技术分析和经济比较是辅助运输方案选择的核心内容,在技术均可行的前提下,首先分析各方案经济比选方法适合范围,并结合辅助运输系统特点建立修正费用现值模型,并以某矿实例分析修正费用现值法在煤矿辅助运输方案选择中的应用,最终确定最优方案,为某煤矿辅助运输方案的选择提供参考依据。修正费用现值法为辅助运输方案选择提供了一种定量比较的思路和方法。