Showing papers by "John F. Nye published in 2016"

The Scale of Production in Western Economic Development: A Comparison of Official Industry Statistics in the

Abstract: We use census data and information on large firms to generate descriptions of structural features of Western industry around 1906. We find that although the United States conforms to existing stereotypes, most other nations do not. German industry stands out as having the smallest plants and firms and the lowest concentration levels both in the aggregate and when grouped by industrial classifications. Equally startling, French levels of plant size and concentration are comparable to those of the United States. We speculate on the importance of these results for rethinking the traditional analysis of industrial development in the early twentieth century.

Events in fields of optical vortices: rings and reconnection

Abstract: It is known (Berry and Dennis 2007 J. Phys. A: Math. Theor. 40 65–74; Berry and Dennis 2012 Eur. J. Phys. 33 723–731) that only one kind of reaction between wave vortices can occur generically in a monochromatic optical field. It appears either in elliptic form as the birth and death of vortex rings or in hyperbolic form as reconnection between separate vortex lines. To make it occur the field must be changed, and, since the codimension is one, it suffices to adjust a single external parameter. The paper analyses a model in which the initial field is produced by superposing n plane waves of the same frequency but different random amplitudes, directions and phases. This is perturbed by an additional plane wave of variable amplitude. The field necessarily obeys the Helmholtz equation and, in spite of the randomness, there is systematic behaviour for n = 3 and 4, which leads to some understanding of the more complicated results for higher values of n. Three plane waves of equal amplitude, perturbed by a fourth, provide a surprising special case, and the remarkable succession of events discovered by (O'Holleran et al 2006a J. Eur. Opt. Soc. Rapid Publ. 1 06008; O'Holleran et al 2006b Opt. Express 14 3039–3044) is fully explained. This is a central point of the paper. Looking at the singularity itself, and initially following Berry and Dennis, the simplest model that satisfies the Helmholtz equation is presented and also the most general local model that uses 'polynomial waves'. We also consider waves that are described simply by a polynomial without any exponential factor. The inclusion of time in the polynomial allows explicitly for quasi-monochromatic waves in which the events occur spontaneously, rather than by adjusting an external control. The circulating phase structure around a simple wave vortex is its most distinctive feature. But in reconnection two such singular vortex lines cross one another and the phase pattern around them must reflect this higher singularity. How it does so is illustrated in the paper.

2D:4D and Lifetime Educational Outcomes: Evidence from the Russian RLMS Survey

Abstract: Is in utero exposure to testosterone (T), measured by the second to fourth digit ratio (2D:4D), associated with lifetime educational attainment? A growing body of work finds exposure to prenatal T to be associated with aggression, physical fitness, performance in computer science, and type of occupation. However, there has not yet been substantial research its relationship with lifetime educational outcomes. Using a large sample drawn from families in Moscow and in the Moscow region from the Russian Longitudinal Measurement Survey (RLMS), we observe clear links between measured 2D:4D and the levels of education obtained by men. Statistically significant positive associations between higher 2D:4D (lower prenatal T) and higher levels of education were found, using difference in means analysis and generalized ordered logit (gologit) regressions. These findings were also robust to using a different subsample. Weaker findings were seen for women. Since many of the earlier findings have shown the benefits of higher prenatal T for achievement, the current finding of a negative effect of prenatal T on educational attainment raises interesting issues about the ambiguous effects of prenatal T and the degree to which the traits it promotes interact with different tasks and social contexts.