401 research outputs found
Realizing complex delayed intentions in young and old adults: The role of planning aids
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
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.
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Reporting and Assessing the Quality of Diagnostic Accuracy Studies for Cervical Cancer Screening and Management.
ObjectiveWe adapted the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool for studies of cervical cancer screening and management and used the adapted tool to evaluate the quality of studies included in a systematic review supporting the 2019 Risk-Based Management Consensus Guidelines.MethodsWe evaluated the quality of all studies included in our systematic review for postcolposcopy (n = 5) and posttreatment (n = 23) surveillance using QUADAS-2 criteria. Subsequently, we adapted signaling questions to indications of cervical cancer screening and management. An iterative process was carried out to evaluate interrater agreement between 2 study authors (M.A.C. and N.W.). Discrepant ratings were discussed, and criteria were adapted accordingly. We also evaluated the influence of study quality on risk estimates and between study variation using stratified subgroup meta-analyses.ResultsTwelve signaling questions for bias assessment that were adapted to or newly developed for cervical cancer screening and management are described here. Interrater agreement on bias assessment increased from 70% to 83% during the adaptation process. Detailed assessment of bias and applicability showed that all studies on postcolposcopy management and 90% of studies on posttreatment management had high risk of bias in at least 1 domain. Most commonly, high risk of bias was observed for the patient selection domain, indicating the heterogeneity of study designs and clinical practice in reported studies.ConclusionsThe adapted QUADAS-2 will have broad application for researchers, evidence evaluators, and journals who are interested in designing, conducting, evaluating, and publishing studies for cervical cancer screening and management
Coupled continuous time random walks in finance
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
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
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
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
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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