4 resultados para discrepancy

em Universidade Complutense de Madrid


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We report on integral-, momentum transfer-and differential cross sections for elastic and electronically inelastic electron collisions with furfural (C5H4O2). The calculations were performed with two different theoretical methodologies, the Schwinger multichannel method with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR) that now incorporates a further interference (I) term. The SMCPP with N energetically open electronic states (N-open) at either the static-exchange (N-open ch-SE) or the static-exchange-plus-polarisation (N-open ch-SEP) approximation was employed to calculate the scattering amplitudes at impact energies lying between 5 eV and 50 eV, using a channel coupling scheme that ranges from the 1ch-SEP up to the 63ch-SE level of approximation depending on the energy considered. For elastic scattering, we found very good overall agreement at higher energies among our SMCPP cross sections, our IAM-SCAR+I cross sections and the experimental data for furan (a molecule that differs from furfural only by the substitution of a hydrogen atom in furan with an aldehyde functional group). This is a good indication that our elastic cross sections are converged with respect to the multichannel coupling effect for most of the investigated intermediate energies. However, although the present application represents the most sophisticated calculation performed with the SMCPP method thus far, the inelastic cross sections, even for the low lying energy states, are still not completely converged for intermediate and higher energies. We discuss possible reasons leading to this discrepancy and point out what further steps need to be undertaken in order to improve the agreement between the calculated and measured cross sections. (C) 2016 AIP Publishing LLC.

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Data from the HEGRA air shower array are used to set an upper limit on the emission of gamma-radiation above 25 (18) TeV from the direction of the radio bright region DR4 within the SNR G78.2 + 2.1 of 2.5 (7.1). 10^-13 cm^-2 sec^-1. The shock front of SNR G78.2 + 2.1 probably recently overtook the molecular cloud Gong 8 which then acts as a target for the cosmic rays produced within the SNR, thus leading to the expectation of enhanced gamma-radiation. Using a model of Drury, Aharonian and Völk which assumes that SNRs are the sources of galactic cosmic rays via first order Fermi acceleration, we calculated a theoretical prediction for the gamma-ray flux from the DR4 region and compared it with our experimental flux limit. Our 'best estimate' value for the predicted flux lies a factor of about 18 above the upper limit for gamma-ray energies above 25 TeV. Possible reasons for this discrepancy are discussed.

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Research on the perception of temporal order uses either temporal-order judgment (TOJ) tasks or synchrony judgment (SJ) tasks, in both of which two stimuli are presented with some temporal delay and observers must judge the order of presentation. Results generally differ across tasks, raising concerns about whether they measure the same processes. We present a model including sensory and decisional parameters that places these tasks in a common framework that allows studying their implications on observed performance. TOJ tasks imply specific decisional components that explain the discrepancy of results obtained with TOJ and SJ tasks. The model is also tested against published data on audiovisual temporal-order judgments, and the fit is satisfactory, although model parameters are more accurately estimated with SJ tasks. Measures of latent point of subjective simultaneity and latent sensitivity are defined that are invariant across tasks by isolating the sensory parameters governing observed performance, whereas decisional parameters vary across tasks and account for observed differences across them. Our analyses concur with other evidence advising against the use of TOJ tasks in research on perception of temporal order.

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La diferencia de longitud de las extremidades, o anisomelia, se define como una condición en la que alguno de los miembros, bien superior o inferior, es notablemente desigual frente al otro. Cuando esta diferencia se detecta en las extremidades inferiores, se conoce como discrepancia en la longitud de las extremidades inferiores (DLEEII, en inglés: LLD, “Leg Length Discrepancy” o LLI, “Leg Length Inequality”) o también dismetría de piernas o del miembro inferior (DM). Las DLEEII son bastante frecuentes en la población adulta, con una prevalencia que se encuentra entre el 40% y el 70% y una magnitud media de desigualdad anatómica mayor de 2 cm en aproximadamente un 0,1% de la misma. Si bien diversas teorías establecen que una DLEEII altera la postura corporal de una persona afectando a determinadas actividades de la vida diaria y pueden ser causa de trastornos del aparato locomotor, no existe un criterio unánime sobre la magnitud de DLEEII necesaria para inducir una respuesta en la postura, así como suponer un impacto clínico. Por otro lado existen estudios que sugieren que la edad de inicio puede ser un factor determinante y que los niños pueden compensar una DLEEII más fácilmente que los adultos que han experimentado su repentina aparición...