Diffusion Indexes With Sparse Loadings

The use of large-dimensional factor models in forecasting has received much attention in the literature with the consensus being that improvements on forecasts can be achieved when comparing with standard models. However, recent contributions in the literature have demonstrated that care needs to be taken when choosing which variables to include in the model. A number of different approaches to determining these variables have been put forward. These are, however, often based on ad hoc procedures or abandon the underlying theoretical factor model. In this article, we will take a different approach to the problem by using the least absolute shrinkage and selection operator (LASSO) as a variable selection method to choose between the possible variables and thus obtain sparse loadings from which factors or diffusion indexes can be formed. This allows us to build a more parsimonious factor model that is better suited for forecasting compared to the traditional principal components (PC) approach. We provide an asymptotic analysis of the estimator and illustrate its merits empirically in a forecasting experiment based on U.S. macroeconomic data. Overall we find that compared to PC we obtain improvements in forecasting accuracy and thus find it to be an important alternative to PC. Supplementary materials for this article are available online.     

简述李光地《离骚经九歌解义》的评注特色

李光地评注《楚辞》的原因有三:一是对屈原遭遇产生共鸣并为其作品所感;二是不满旧注;三是宣扬儒家清廉节操的需要.此书的主要评注方法是先总后分,既较注重点明章句之间的相承关系、字词章句的比喻义,以及作品艺术特征的分析,也注重在阐发新意的同时兼驳旧说.其评注的不足主要是任意删减《九歌》篇目和一些说解错误.     

Complete moment convergence and Lr convergence for asymptotically almost negatively associated random variables

In this paper, we investigate the complete moment convergence and L_r convergence for maximal partial sums of asymptotically almost negatively associated random variables under some general conditions. The results obtained in the paper generalize some corresponding ones for negatively associated random variables.     

Senior centres in the lives of older Americans: implications for Chinese older adults

As a critical community resource, the senior centre has provided older Americans with a wide array of recreational, nutritional, health, and social service programmes. Funding resources include the Older Americans Act allocations, local organisations and governments, national charities, voluntary associations, and religious associations. The types of programmes offered at a senior centre reflect two models: social agency model or voluntary organisation model. The five most popular programmes are nutrition, health and fitness, recreation, volunteering, and social services. Participation in senior centre activities has positive impacts on the overall well-being of older adult participants. With the rapid growth in the ageing population and improved life expectancy in China, senior centres may serve as a focal point for Chinese older adults by providing a broad spectrum of social services to enhance the well-being of community-dwelling older adults, to support their independence and dignity, and to facilitate ageing in place in later life.     

首都第二机场建设与航空人才需求调研

首都第二机场的建设已成定局,由此而引起的大量人才需求是各层次学校所关注的焦点。北京经济管理职业学院是否能抓住这一得天独厚的机遇,将是未来几年对北京经济管理职业学院的考验,因此根据近几年来对首都二机场建设的资料的收集和调研,了解了机场建设对航空人才的需求,为学院的发展提供了建设性的参考性意见。     

历史文献学视野下的重大历史事件

重大历史事件的提出源于国家文艺创作政策,是重大历史题材的内核。从历史文献学的视角来看,重大历史事件的文献形态表现为本源事件、衍生事件和文本事件。重大历史事件的衍生特征主要体现为本源事件的内容选择性、视角多样性、衍生多态性和历史叙事的结构层次性。重大历史事件具有文献能产性,其根本动力来源于历史主体的社会认可需要、纪念活动的客观物证需要和文艺创作的传奇叙事需要。     

经济上囊括与社会政治上驱逐———论《唐老亚》对华裔美国人精神和文化形象的重建简

赵健秀小说《唐老亚》重建华裔美国人精神和文化形象。在小说中，作者重新刻画了华裔美国人积极的精神风貌，书写了华裔先辈修建铁路但被美国白人社会所隐没的历史，重新解释了被白人社会所扭曲和谬传的儒家思想，揭示了华裔美国人在经济上被囊括与社会政治上被驱逐的尴尬境地，从而对华裔美国人的形象在精神上和文化上进行了建构。     

我国环境保护发展进程回顾与展望

我国在工业化进程中虽面临人口、贫困、资源、环境、技术等很多困难,但仍然从中国的国情出发,发展低碳经济,坚定地走保护环境的可持续发展之路。自主、自愿、自我约束的实施减排行动,表明我国作为一个发展中国家在环境保护问题上的坚定立场和决心,在世界环保舞台上树立了一个负责任大国的形象。但我国的环境保护战略的实施还有一段很长的路要走,还需在绿色刺激计划、低碳技术、相关产业链、技术机制运行上,进一步加大改进力度,走出一条具有中国特色的低碳经济发展道路。     

20世纪20年代的乡土文学状况

20世纪20年代的乡土文学作为乡土文学流派的源头，对乡土文学的发展、流变具有重要的启悟意义。对此一时期的乡土文学研究，概念研究、思想主题研究以及艺术美学研究是研究的中心和重点，对后起的乡土文学创作和评论产生了决定性的影响。     

浅析水墨动画片的空间意识

水墨动画是中国传统水墨画与动画技术相结合的颇具民族特色的一种动画片种.它将中国传统水墨画的题材、笔墨节奏、审美空间意识引入到动画制作中,呈现"动画化"的水墨艺术.本文首先分析了传统水墨画所表现的节奏化自然、"阴阳"、"有无"的空间意识,再从属于电影范畴的水墨动画片的视听语言角度来阐述水墨艺术仅仅"动起来"还不够,还要达到真正意义上的"动画化",才能表现出比传统水墨画更有意蕴的空间意识.