Cluster Dynamics: New Evidence and Projections for Computing Services in Great Britain*

Abstract. This paper tests some of the main hypotheses about the importance of horizontal clusters for the growth of employment in small firms using data from Computing Services in Great Britain. In the main section of the paper, spatial econometric models are estimated controlling for supply‐ and demand‐side conditions to isolate the effect of initial cluster intensity. The paper then projects cluster development using the fitted model, showing how clusters are likely to emerge and intensify. One aspect of the paper is the existence of a de‐clustering mechanism due to congestion effects.     

Fluidized sandstone intrusions as an indicator of Paleostress orientation, Santa Cruz, California

The late Miocene sandstone intrusions of northern Santa Cruz County, California, are the largest subaerial exposures of clastic intrusions on earth. The intrusions are sourced from a sandstone, underlying mudstone, accumulated in an outer shelf to upper slope environment. Dikes are the most frequent intrusion type, reach the greatest thickness and tend to strike north‐east and dip steeply. One giant dike is more than 150 m wide. Sills are least frequent, locally > 8 m thick and have no clear preferred geographical distribution. Clustered intrusions are commonly < 10 cm thick and mostly composed of dikes of various attitudes. The majority of the intrusions probably were injected shallowly as some extrude onto the seafloor. The local seafloor extrusion also indicates injection during the deposition of the Santa Cruz Mudstone (7–9 Ma). The intrusions are concentrated at the basin margin. Fluid pressure at the centre of the basin and perhaps hydrocarbons were communicated to the basin margin through the then sand, causing fluid overpressures that contributed to the fluidization and intrusion into the overlying mudstone. Primarily north‐east‐striking, steeply dipping dikes and secondarily, shallowly dipping sills are most significant in terms of regional connectivity of intrusions and physical dilation of the formation. The orientation of the dikes and sills indicates a regional stress field with a horizontal NE–SW maximum and a NW–SE minimum compressive direction. The simultaneous development of dikes and sills suggests similar magnitudes of the minimum and intermediate principal stresses. Preferential weakness along bedding contributed to the development of sills. Palaeomagnetic data indicate no significant block rotation around a vertical axis. The maximum principal stress direction indicated by the intrusions is about 55° to the San Gregorio Fault and about 70° to the San Andreas Fault during the late Miocene. This stress field is similar to the modern stress field and suggests moderate fault weakness.     

The Identity of Capitalists and the Legitimacy of Capitalism: Sri Lanka since Independence

In many Asian countries, the early decades of independence after World War II were marked by tension between ‘indigenous’ political elites and business elites that were in large part alien, or from minority ethnic groups. This tension was one reason for the preference that most governments showed for statist and nationalist economic policies. It has abated in most cases; political and business elites now tend to pursue more co-operative strategies. Much of the explanation for this lies in changes in the international political economy that made market-oriented economic policies more attractive to political elites. There are in addition internal political reasons for this rapprochement. These vary from case to case, and have been explored in most detail by scholars in relation to the Southeast Asian countries where Overseas Chinese have dominated larger scale business. This article extends this literature by examining the causes of the gradual rapprochement between ‘majority’ politics and ‘minority’ business in Sri Lanka.