A worldwide correlation for exponential bed particle size variation in subaerial aqueous flows

The particle size of the bed sediments in or on many natural streams, alluvial fans, laboratory flumes, irrigation canals and mine waste deltas varies exponentially with distance along the stream. A plot of the available worldwide exponential bed particle size diminution coefficient data against stream length is presented which shows that all the data lie within a single narrow band extending over virtually the whole range of stream lengths and bed sediment particle sizes found on Earth. This correlation applies to both natural and artificial flows with both sand and gravel beds, irrespective of either the solids concentration or whether normal or reverse sorting occurs. This strongly suggests that there are common mechanisms underlying the exponential diminution of bed particles in subaerial aqueous flows of all kinds. Thus existing models of sorting and abrasion applicable to some such flows may be applicable to others. A comparison of exponential laboratory abrasion and field diminution coefficients suggests that abrasion is unlikely to be significant in gravel and sand bed streams shorter than about 10 km to 100 km, and about 500 km, respectively. Copyright (C) 1999 John Wiley & Sons, Ltd.

Global flows of foreign talent: Identity anxieties in Singapore's ethnoscape

This paper draws on Appadurai's (1996) concept of ethnoscapes — the global flow of people or what has become increasingly popularized as the global flow of talent. Singapore has initiated a foreign talent policy to compete for a global pool of talent to make up for its shortfall of indigenous work-force. The rationale for recruiting foreign talent is informed by a nationalist competitive ideology to sustain Singapore in the new knowledge-based economy. This paper examines the competing and dissenting discourses surrounding the foreign talent policy. It argues that the mobility of migratory flow has transformative and disruptive effects at the level of culture and the identity landscape of Singapore, where its discursive cultural boundaries are drawn according to a nationalist framework. Drawing on theories and concepts of ‘diaspora’, ‘hybridity’, and ‘third space’, these are the political and cultural issues that this paper attempts to tease out. [ABSTRACT FROM AUTHOR]