Habit Formation in an Overlapping Generations Model with Borrowing Constraints

We introduce habit‐formation in the three‐period OLG borrowing‐constrained framework of Constantinides et al. (2002) by allowing the utility of the middle‐aged (old) to depend on consumption when young (middle‐aged). This specification enables us to separate the effect of the two habit parameters (middle‐aged and old) since each representative age‐group can face different levels of habit persistence. The two‐habit setup underlines some important issues with regards to savings and security returns which do not always conform to the standard findings in the literature. In addition, the model produces equity premium consistent with US data for relatively small levels of risk aversion.     

Tourism and climate change: a review of threats and adaptation strategies for Africa

The intersection of tourism and climate change has seen significant research over the past two decades, focusing particularly on issues of mitigation and adaptation in the global North. Research output has predominantly been centred on the Mediterranean and Nordic countries and number of localities in North America. The global South has seen significantly less investigation, despite having significantly lower adaptive capacity to the impacts of climate change, and numerous countries with rapidly growing tourism sectors. The African continent specifically has seen appreciably less research than other countries in the global South, despite arguably having the lowest adaptive capacity and projections of severe impacts of climate change to the tourism sector from temperature increases, changes in precipitation volume and sea level rise. This paper therefore presents a review of the existing literature on adaptation strategies of tourism sectors and participants in African countries. The crucial argument of this paper is in highlighting the need for an increase in research into the threats of climate change to tourism in African countries, identifying future research trajectories. The development of such knowledge would assist in the development of adaptation and mitigation strategies for these most vulnerable tourism economies.     

APPLYING A GENETIC ALGORITHM TO INTERNATIONAL DIVERSIFICATION OF EQUITY PORTFOLIOS: A SOUTH AFRICAN INVESTOR PERSPECTIVE

This paper uses the genetic algorithm (GA) approach to generate a portfolio optimisation scenario of a South African investor who seeks to maximise return from investing in S&P500, FTSE100, NASDAQ, DOWJONES, CAC40 and the DAX from January 1, 2005, to January 31, 2008, but facing exchange rate risk. The GA searches for the optimal solution in the entire set of financial constraints without looking for partial derivatives of the utility function. Whereas most financial problems require a non‐linear and time‐varying model, the GA, with its survival principle of offspring chromosomes, is better suited to this type of problem than local optimisation methods. The performance of the GA is compared with two non‐linear models, namely the quadratic mean‐variance (QMV), which maximises the portfolio mean‐variance, and the quadratic variance minimisation (QVM), which minimises the portfolio variance. The results show that neither the QMV nor the QVM takes into account the domestic investors' risk attitude towards investing in foreign equities and therefore does not provide any international diversification benefits. In addition, the bootstrapping scenario of 10,000 simulations reveals that neither the QMV nor the QVM outperforms the GA in terms of Sharpe ratio and flexibility in dealing with investors' risk attitude towards investing in foreign equities denominated in foreign currencies.     

利用世博契机,把崇明打造成为“未来岛”——基于城市品牌定位的思考

伴随沪崇苏大桥的开工及中央提出科学发展观,具有国际生态岛地位的崇明如何发展正吸引着大家的关注,地方政府在集思广益基础上将崇明定位为国际现代化生态岛。文章认为这只是完成了基础定位,建议崇明以城市品牌定位理论为指导确立＂未来岛＂的品牌定位,并以婚庆业举例说明此定位发展的巨大前景。进而结合当前迎世博背景,针对利用世博契机,促进崇明建设未来岛,提出若干建议。     

Testing for weak-form efficiency of crude palm oil spot and future markets: new evidence from a GARCH unit root test with multiple structural breaks

There is a sizeable literature that tests for weak-form efficiency in commodity and energy spot and future prices. While many studies now allow for multiple structural breaks to address the criticism that conventional unit root tests have low power to reject the unit root null in the presence of structural change, the extant literature overlooks the fact that conventional unit root tests are biased in the presence of conditional heteroscedasticity. We apply a recently developed generalized autoregressive conditional heteroscedasticity (GARCH) unit root test with multiple structural breaks to crude palm oil spot and future prices and find much more evidence against weak-form efficiency than that found using tests that fail to allow for conditional heteroscedasticity. Our results point to the importance of allowing for heteroscedasticity when testing for efficiency in commodity and energy spot and future prices.     

Global modelling revisited

Reasons for the great impact of World Dynamics and Limits to Growth include their addressing the correct audience (the public), and the ability of systems dynamics clearly to handle and communicate information on complex and often little understood areas. Modelling projects should usually be global or national (not regional), draw heavily on mental and not just written and numerical databases, and have time horizons of perhaps 100 years. Sadly, critics of Worlds 2 and 3 have yet to come to grips with the fundamental messages presented there, although these messages are becoming increasingly vital.     

The scope of application of management accounting methods in Polish enterprises

The transformation of Poland’s economic system in the 1990s as a result of transition from a centrally planned economy to a market-based system involves significant changes in the regulatory context and in accounting practice and education.This paper presents the scope of application of management accounting concepts and methods in 60 Polish enterprises covered by a questionnaire survey carried out by the author between November 1998 and December 1999 in enterprises located in central and southern Poland. The selected companies were interviewed by means of a postal survey, with inquiry forms delivered in person in some cases.The detailed analyses carried out in this paper and the conclusions presented are also based on information obtained from documentary evidence kept by the enterprises and from direct interviews conducted in the course of work in teams engaged in analysis and assessment of cost accounting practices and in management accounting system design in a number of large and medium Polish enterprises.The empirical research carried out is aimed at verification of a number of hypotheses including the following: • modification of cost accounting systems and implementation of management accounting tools in Polish enterprises is brought about by many different factors, the most important being growth of competition and ownership changes in business entities, • Polish enterprises mostly implement the methods and techniques of operational management accounting, • short-term budgeting for cost centres is the most widely used method of management accounting.     

原型范畴理论视角下的英语时态认知解读

原型范畴理论作为认知语言学概念的基础近年来逐渐得到了语言学家的重视。原型范畴理论可以用于英语教学并对英语时态具有一定的解释力,从而为英语时态教学开辟新视角。本文以一般现在时态、一般过去时态、一般将来时态为例,探索原型范畴理论在英语时态教学中的应用。希望能推动该理论在英语时态教学中的应用。     

对文娱新闻未来走向的一些思考

理论界对文娱新闻的关注大多集中在对其低俗化的批判上，对其社会价值、未来发展方向等深层次的研究相对比较缺乏。本文对文娱新闻的未来发展进行了大胆的预测。文娱新闻的发展有赖于社会的进步和传媒业的发展，同时也有赖于从业人员文化素质的提高和思想水平的进步。文娱新闻包含娱乐，但并不是只有浅表化的娱乐，而是要在娱乐的同时构筑较高的文化品住，在娱乐的过程中提升文化，提高素养，这才是文娱新闻可持续发展之道。     

Tourism in the system of industrial society

Recreation and tourism are integral parts of the whole industrial social system. Viewed thus, tourism, so successful in the past two decades, seems clearly doomed to radical change. Many signs in the universe of work-habitate-leisure-travel indicate that the present system does not satisfy the human needs of traveler, host, and ultimately the social system. One inevitable result of forecast change, is a new, humane understanding of leisure and tourism; one should begin forging it before the opportunity for choice and reason disappears.