401 research outputs found

    Realizing complex delayed intentions in young and old adults: The role of planning aids

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    Although it has been suggested that the delayed realization of intended actions should benefit from appropriate intention planning, empirical evidence on this issue is scarce. In three experiments, we examined whether and which planning aids provided in the intention formation phase affect delayed intention realization in young and old adults. One finding was that intention planning directly affected delayed intention realization: instructing participants to include the cue for appropriate intention initiation in their plans benefited delayed performance. Another finding was that older adults' performance was improved when they were guided in structuring their plan in combination with guidance in implementing this plan after a delay. In sum, the results point to the importance of plan-related factors for understanding the delayed realization of intended action

    On the interpretation of Michelson-Morley experiments

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    Recent proposals for improved optical tests of Special Relativity have renewed interest in the interpretation of such tests. In this paper we discuss the interpretation of modern realizations of the Michelson-Morley experiment in the context of a new model of electrodynamics featuring a vector-valued photon mass. This model is gauge invariant, unlike massive-photon theories based on the Proca equation, and it predicts anisotropy of both the speed of light and the electric field of a point charge. The latter leads to an orientation dependence of the length of solid bodies which must be accounted for when interpreting the results of a Michelson-Morley experiment. Using a simple model of ionic solids we show that, in principle, the effect of orientation dependent length can conspire to cancel the effect of an anisotropic speed of light in a Michelson-Morley experiment, thus, complicating the interpretation of the results.Comment: To appear in Phys.Lett.

    Coupled continuous time random walks in finance

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    Continuous time random walks (CTRWs) are used in physics to model anomalous diffusion, by incorporating a random waiting time between particle jumps. In finance, the particle jumps are log-returns and the waiting times measure delay between transactions. These two random variables (log-return and waiting time) are typically not independent. For these coupled CTRW models, we can now compute the limiting stochastic process (just like Brownian motion is the limit of a simple random walk), even in the case of heavy tailed (power-law) price jumps and/or waiting times. The probability density functions for this limit process solve fractional partial differential equations. In some cases, these equations can be explicitly solved to yield descriptions of long-term price changes, based on a high-resolution model of individual trades that includes the statistical dependence between waiting times and the subsequent log-returns. In the heavy tailed case, this involves operator stable space-time random vectors that generalize the familiar stable models. In this paper, we will review the fundamental theory and present two applications with tick-by-tick stock and futures data.Comment: 7 pages, 2 figures. Paper presented at the Econophysics Colloquium, Canberra, Australia, November 200

    Spatial patterns of scour and fill in dryland sand bed streams

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    Reproduced with permission of the publisher. © 2006 American Geophysical UnionSpatial patterns of scour and fill in two dryland ephemeral stream channels with sandy bed material have been measured with dense arrays of scour chains. Although the depth and areal extent of bed activity increased with discharge, active bed reworking at particular locations within the reaches resulted in downstream patterns of alternate shallower and deeper areas of scour. The variation was such that mean scour depths for individual cross sections varied about the mean for the reach by a factor of 2–4 while the locus of maximum scour traced a sinuous path about the channel centerline. The wavelength of the pattern of scour was about seven times the channel width. During each event, compensating fill returned the streambeds to preflow elevations, indicating that the streams were in approximate steady state over the period of study. Although the patterns of periodically enhanced scour along alternate sides of the channels are consistent with models of periodically reversing helical flow, further work is required to identify the causal relationships between patterns of flow and sediment transport in dryland sand bed channels

    Planeamiento tributario y su relación en la determinación del impuesto a la renta en la empresa ERBA EIRL, Tarapoto, 2018

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    La investigación titulada: Planeamiento tributario y su relación en la determinación del impuesto a la renta en la empresa ERBA EIRL, Tarapoto, 2018; tuvo como objetivo general evaluar la relación del planeamiento tributario y la determinación del impuesto a la renta en la empresa ERBA EIRL, Tarapoto, 2018. El tipo de estudio fue básico y diseño no experimental, la muestra estuvo constituida por el gerente general y contador de la empresa, las técnicas de recolección de datos fueron la entrevista, observación y análisis documental. Los resultados dan la existencia de un bajo cumplimiento de actividades relacionadas a llevar un correcto planeamiento tributario en un 83%; además el que se realizó fue inadecuado, la empresa al no presentar un correcto planeamiento sumo un resultado de S/. 7,874.00 según los ingresos registrados; sin embargo, al llevar un adecuado planeamiento tributario incurrió a un resultado de S/. 5,249.00 de impuesto. Se concluye que existe una relación indirecta y significativa entre el planteamiento tributario y la determinación del impuesto a la renta, esto comprueba que a mayor planeamiento tributario menor será el impuesto a pagar, en la empresa ERBA EIRL, Tarapoto

    Wesson's IMT with a Weylian bulk

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    The foundations of Wesson's induced matter theory are analyzed. It is shown that the 5D empty bulk must be regarded rather as a Weylian space than as a Riemannian one.The framework of a Weyl-Dirac version of Wesson's theory is elaborated and discussed. The bulk possesses in addition to the metric tensor a Weylian connection vector as well Dirac's gauge function; there are no sources (mass, current) in the bulk. On the 4D brane one obtains a geometrically based unified theory of gravitation and electromagnetism with mass, currents and equations induced by the 5D bulkComment: 29 page

    Observable frequency shifts via spin-rotation coupling

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    The phase perturbation arising from spin-rotation coupling is developed as a natural extension of the celebrated Sagnac effect. Experimental evidence in support of this phase shift, however, has yet to be realized due to the exceptional sensitivity required. We draw attention to the relevance of a series of experiments establishing that circularly polarized light, upon passing through a rotating half-wave plate, is changed in frequency by twice the rotation rate. These experiments may be interpreted as demonstrating the role of spin-rotation coupling in inducing this frequency shift, thus providing direct empirical verification of the coupling of the photon helicity to rotation. A neutron interferometry experiment is proposed which would be sensitive to an analogous frequency shift for fermions. In this arrangement, polarized neutrons enter an interferometer containing two spin flippers, one of which is rotating while the other is held stationary. An observable beating in the transmitted neutron beam intensity is predicted.Comment: LaTeX, 15 pages with 4 PostScript figures, submitted to Phys. Lett.
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