Methodological issues in measures of imitative reaction times

Ideomotor (IM) theory suggests that observing someone else perform an action activates an internal motor representation of that behaviour within the observer. Evidence supporting the case for an ideomotor theory of imitation has come from studies that show imitative responses to be faster than the same behavioural measures performed in response to spatial cues. In an attempt to replicate these findings, we manipulated the salience of the visual cue and found that we could reverse the advantage of the imitative cue over the spatial cue. We suggest that participants utilised a simple visuomotor mechanism to perform all aspects of this task, with performance being driven by the relative visual salience of the stimuli. Imitation is a more complex motor skill that would constitute an inefficient strategy for rapid performance

Tales of Clemson, 1936-1940

This memoir of Clemson College life, from matriculation in 1936 to graduation in 1940, is a sequel to the author\u27s recollection of early youth in Charleston, South Carolina. Tales of Clemson 1936-1940 vividly recreates the undergraduate days before the outbreak of war in Europe and the Pacific. President Emeritus Walter Cox (Class of 1939) and distinguished journalist Earl Mazo have given the book its foreword and postscript, respectively. Dr. Williams recalls Clemson\u27s own luminaries, mentors, and interesting personalities from a bygone era.https://tigerprints.clemson.edu/cudp_mono/1018/thumbnail.jp

Coupled probabilistic and point kinetics modelling of fast pulses in nuclear systems

AbstractThis paper describes a probabilistic method of modelling point nuclear systems with low numbers of neutrons including the effects of delayed neutron precursors and its coupling with standard point kinetics equations. This coupling allows the simulation of the non-deterministic progression of a system transitioning from subcritical to supercritical and the resulting power peak. Through analysis of large numbers of realisations various statistical parameters of such transients can be obtained. The method of simulation presented here successfully replicates the survival and extinction probabilities predicted by the Backwards Master Equation and experimental and analytic results from the literature regarding the Godiva reactor and extends the examination of that reactor. In particular the effect of delayed neutrons on the simulated response of Godiva is highlighted. With its implementation in a parallel computer code, the model is able to simulate at a reasonable speed a range of systems where low neutron populations are important

Achieving Efficient Strong Scaling with PETSc using Hybrid MPI/OpenMP Optimisation

The increasing number of processing elements and decreas- ing memory to core ratio in modern high-performance platforms makes efficient strong scaling a key requirement for numerical algorithms. In order to achieve efficient scalability on massively parallel systems scientific software must evolve across the entire stack to exploit the multiple levels of parallelism exposed in modern architectures. In this paper we demonstrate the use of hybrid MPI/OpenMP parallelisation to optimise parallel sparse matrix-vector multiplication in PETSc, a widely used scientific library for the scalable solution of partial differential equations. Using large matrices generated by Fluidity, an open source CFD application code which uses PETSc as its linear solver engine, we evaluate the effect of explicit communication overlap using task-based parallelism and show how to further improve performance by explicitly load balancing threads within MPI processes. We demonstrate a significant speedup over the pure-MPI mode and efficient strong scaling of sparse matrix-vector multiplication on Fujitsu PRIMEHPC FX10 and Cray XE6 systems

Proposed Global Stratotype Sections and Points for the bases of the Selandian and Thanetian stages (Paleocene Series)

Prepared for the International Subcommission on Paleogene Stratigraph

Unital quantum operators on the Bloch ball and Bloch region

For one qubit systems, we present a short, elementary argument characterizing unital quantum operators in terms of their action on Bloch vectors. We then show how our approach generalizes to multi-qubit systems, obtaining inequalities that govern when a ``diagonal'' superoperator on the Bloch region is a quantum operator. These inequalities are the n-qubit analogue of the Algoet-Fujiwara conditions. Our work is facilitated by an analysis of operator-sum decompositions in which negative summands are allowed.Comment: Revised and corrected, to appear in Physical Review