Interactive learning and localised knowledge in globalising learning economies

This article analyses the role of interactive learning and localised knowledge in globalising learning economies. Some authors argue that as a result of globalisation and codification processes the importance of local, contextual knowledge and localised learning is decreasing, and, thus, the competitive advantage of high-cost regions (and nations) are steadily being undermined. Other authors maintain that much strategic knowledge, tacit as well as codified, is disembodied (i.e., knowledge which is the result of positive externalities of the innovation process), and, thus, remains `sticky'. Important parts of the learning process continue to be localised as a result of the enabling role of geographical and social proximity in stimulating interactive learning, which taken together represent strong `untraded interdependencies' constituting important context conditions for regions to remain innovative and competitive. The article argues that learning economies should be used to conceptualise a specific historical period of capitalism in which knowledge and learning has attained an increasing importance in the economy. This period of capitalist development is also referred to as post-Fordism.     

Highly localised distribution patterns of juvenile sea cucumber Australostichopus mollis

Information on the environmental characteristics of the juvenile habitat of many deposit-feeding sea cucumber species is limited, despite most fished species exhibiting rapid localised depletion. The current study combined large and small scale surveying techniques within a New Zealand harbour to identify areas with high densities of juvenile Australostichopus mollis, a commercially valuable aspidochirote holothurian. Data from detailed surveys were used to relate densities of juveniles and adults with measures of physical habitat characteristics including depth, sediment facies type, grain size range, as well as measures of chlorophyll-a, phaeopigment, carbon and nitrogen content of surface sediment. Results revealed a highly localised distribution of juvenile A. mollis focused on one site associated with an area of high adult density. Sites of high juvenile A. mollis density were characterised by sediment qualities favouring epibenthic detritivorous deposit feeding, including high nitrogen content, high phaeopigment:chlorophyll-a ratio and small grain size. The high-density juvenile site had facies that were further characterised by the presence of large shell fragments (>10 cm length) of the horse mussel (Atrina zelandica), which may provide a unique settlement microhabitat for early juveniles. Unlike some other sea cucumber species, juvenile A. mollis shows no distinct spatial separation from adult sea cucumbers, no association with dense macroalgae and no clear preference for shallower depths than adults. Overall, the results illustrate the highly localised pattern of recruitment of this species to a widely distributed adult population, which may help to explain the lack of previous observations of juveniles in this species. These results indicate the importance of identifying and protecting what appear to be very specific juvenile habitats in deposit-feeding sea cucumbers to ensure continuing recruitment to exploited populations.     

Micromechanics of vortices in granular media: connection to shear bands and implications for continuum modelling of failure in geomaterials

Recent analysis of data from triaxial tests on sand and discrete element simulations indicate the final pattern of failure is encoded in grain motions during the nascent stages of loading. We study vortices that are evident from grain displacements at the start of loading and bear a direct mathematical connection to boundary conditions, uniform continuum strain and shear bands. Motions of three grains in mutual contact, that is, 3‐cycles, manifest vortices. In the initial stages of loading, 3‐cycles initiate a rotation around a region Ω^* where the shear band ultimately develops. This bias sets a course in 3‐cycle evolution, determining where they will more likely collapse. A multiscale spatial analysis of 3‐cycle temporal evolution provides quantitative evidence that the most stable, persistent 3‐cycles degrade preferentially in Ω^*, until essentially depleted when the shear band is fully formed. The transition towards a clustered distribution of persistent 3‐cycles occurs early in the loading history—and coincides with the persistent localisation of vortices in Ω^*. In 3D samples, no evidence of spatial clustering in persistent 3‐cycle deaths is found in samples undergoing diffuse failure, while early clustering manifests in a sample that ultimately failed by strain localisation. This study not only delivered insights into the possible structural origins of vortices in dense granular systems but also a tool for the early detection of the mode of failure—localised versus diffuse—a sample will ultimately undergo. Copyright © 2014 John Wiley & Sons, Ltd.     

Role of nitrogen and oxygen in emission of Si quantum dots formed by pulse laser

Silicon quantum dots fabricated by nanosecond pulsed laser in nitrogen, oxygen or air atmosphere have enhanced photoluminescence (PL) emission with the stimulated emission observed at about 700 nm. It is difficult to distinguish between the photoluminescence peaks emitted from samples prepared in different atmospheres. The reason for the appearance of similar peaks may be the similar distribution of the localised states in the gap for different samples when silicon dangling bonds of quantum dots are passivated by nitrogen or oxygen. It is revealed that both the kind and the density of passivated bonds on quantum dot surface prepared in oxygen or nitrogen have a strong influence on the enhancement of PL emission.