The ‘Urban Age’ in Question

Foreboding declarations about contemporary urban trends pervade early twenty‐first century academic, political and journalistic discourse. Among the most widely recited is the claim that we now live in an ‘urban age’ because, for the first time in human history, more than half the world's population today purportedly lives within cities. Across otherwise diverse discursive, ideological and locational contexts, the urban age thesis has become a form of doxic common sense around which questions regarding the contemporary global urban condition are framed. This article argues that, despite its long history and its increasingly widespread influence, the urban age thesis is a flawed basis on which to conceptualize world urbanization patterns: it is empirically untenable (a statistical artifact) and theoretically incoherent (a chaotic conception). This critique is framed against the background of postwar attempts to measure the world's urban population, the main methodological and theoretical conundrums of which remain fundamentally unresolved in early twenty‐first century urban age discourse. The article concludes by outlining a series of methodological perspectives for an alternative understanding of the contemporary global urban condition.     

最小平方误差受限的FIR滤波器设计

在设计FIR滤波器时,往往会指定过渡带大小,但过渡带的引入只是为了便于滤波器的设计,而并不是物理上的需要,所以在设计中仅需指定截至频率。这是第一个设计理念。此外,在FIR滤波器的设计中存在两种准则:一是等波纹设计准则 (即最大误差最小化或者Chebyshev准则 ),另一种是平方误差最小准则。但在现实中两种准则往往要同时兼顾,所以仅基于其中一种准则来设计不能得到最佳结果。这是第二个设计理念。基于上述两种设计理念,提出了一种新的FIR滤波器设计算法。该算法采用最陡梯度下降法来对平方误差最小化下的最佳滤波器系数进行迭代修正,得到最佳结果。     

The virtues of dialogue between academics and businessmen

This article aims to understand the process of production of knowledge in the field of business organisation and in problems of administration. It argues that the acquisition of this type of knowledge is greatly assisted by the developments of dialogue between academics and industrialists. It looks at a method which has been applied in England during the period late 1940s to early 1970s in three academic seminars: the Seminar in Problems of Administration at the LSE (1947–1972); the Industrial Seminar at Birmingham University (late 1950s?1972); and the BPhil Seminar in Economics of Industry at the University of Oxford (1957–1974). By the mid-1970s, these three seminars had ceased to exist and left room for the rapid development of management studies, on the one hand, and the formalisation of industrial economics (game theory), on the other.     

The predictive failure of the Baba, Hendry and Starr model of M1

restored a stable specification for M1 demand using an error-correction model which allowed for learning about new assets and incorporated a volatility term in long-term interest rates. Our study replicated their in-sample results, but found that their model completely breaks down over longer sample periods. We argue that this predictive failure could have been anticipated by sensitivity analysis. Their specification appears to have underestimated the interest rate elasticity of money demand because of the learning-adjustment mechanism. Our results also call into question their basic use of volatility in narrow money demand models.     

Valuation implications of pharmaceutical companies' R&D regulatory approval notifications

This paper examines shareholder wealth effects surrounding applications to, and approvals by, the United States Food and Drug Administration (FDA) for firms listed on the New York (NYSE) and London (LSE) stock exchanges. Applications to the FDA for drug approvals significantly increase shareholder wealth for NYSE firms only. The increase is driven by applications for enhancements to existing drugs, with the market anticipating the application, thus suggesting information leakage. FDA approvals also significantly increase shareholder wealth in both markets. However, there is no evidence of information leakage and the significant post-event abnormal returns support the attention-grabbing hypothesis. Enhanced drug approvals are value-relevant for both markets, which highlights the contribution of real-options to firm value.