6,245 research outputs found
El potencial de la teoría cognitiva en la enseñanza de la contabilidad y auditoría
El artículo examina la asimilación de dos conceptos contables complejos: la imagen fiel (TFV) y el valor razonable (FV) en una muestra de estudiantes de Contabilidad Financiera. El objetivo es evaluar la opinión de los estudiantes sobre TFV y FV durante su educación y detectar si las percepciones cambian con su nivel académico y madurez. La metodología utilizada es una encuesta de opinión. Las respuestas obtenidas muestran que los estudiantes consideran que la TFV es un concepto superior a otros principios contables. Además, en el estudio se observa que las respuestas de los estudiantes dependen del nivel académico y la madurez. Por último, se considera que los postulados que establece la teoría cognitiva podrían servir a los instructores en materia de contabilidad y organismos reguladores para mejorar el proceso de aprendizaje así como la calidad de la información financiera.This paper examines the understanding of two complex accounting concepts: true and fair view (TFV) and fair value (FV) by students in Financial Accounting. The correct assimilation of these concepts is assessed as to whether there are differences in concept perception due to academic level and maturity. We use a survey to examine the perception and assimilation of the TFV and FV. The evidence suggests that accounting students consider that TFV is a superior accounting concept over other accounting principles. Additionally, the study identifies a pattern of change depending on the academic level and maturity of the participants. On discovering differences, a proposal is made to use the Cognitive Load Theory (CLT) by standard setters and instructors in accounting and auditing to improve the learning process and the quality of financial information.Ministerio de Innovación y Ciencia DER2009-09539 ECO2010-17463 ECO2010-21627 DER2012-33367 DER2015-67918PConsejería de Educacion y Ciencia Castilla-La Mancha POII10-0134-5011Universidad de Alcalá CCG20014/HUM-03
How BAO measurements can fail to detect quintessence
We model the nonlinear growth of cosmic structure in different dark energy
models, using large volume N-body simulations. We consider a range of
quintessence models which feature both rapidly and slowly varying dark energy
equations of state, and compare the growth of structure to that in a universe
with a cosmological constant. The adoption of a quintessence model changes the
expansion history of the universe, the form of the linear theory power spectrum
and can alter key observables, such as the horizon scale and the distance to
last scattering. The difference in structure formation can be explained to
first order by the difference in growth factor at a given epoch; this scaling
also accounts for the nonlinear growth at the 15% level. We find that
quintessence models which feature late , rapid transitions towards
in the equation of state, can have identical baryonic acoustic
oscillation (BAO) peak positions to those in CDM, despite being very
different from CDM both today and at high redshifts .
We find that a second class of models which feature non-negligible amounts of
dark energy at early times cannot be distinguished from CDM using
measurements of the mass function or the BAO. These results highlight the need
to accurately model quintessence dark energy in N-body simulations when testing
cosmological probes of dynamical dark energy.Comment: 10 pages, 7 figures, to appear in the Invisible Univers International
Conference AIP proceedings serie
The effects of halo alignment and shape on the clustering of galaxies
We investigate the effects of halo shape and its alignment with larger scale
structure on the galaxy correlation function. We base our analysis on the
galaxy formation models of Guo et al., run on the Millennium Simulations. We
quantify the importance of these effects by randomizing the angular positions
of satellite galaxies within haloes, either coherently or individually, while
keeping the distance to their respective central galaxies fixed. We find that
the effect of disrupting the alignment with larger scale structure is a ~2 per
cent decrease in the galaxy correlation function around r=1.8 Mpc/h. We find
that sphericalizing the ellipsoidal distributions of galaxies within haloes
decreases the correlation function by up to 20 per cent for r<1 Mpc/h and
increases it slightly at somewhat larger radii. Similar results apply to power
spectra and redshift-space correlation functions. Models based on the Halo
Occupation Distribution, which place galaxies spherically within haloes
according to a mean radial profile, will therefore significantly underestimate
the clustering on sub-Mpc scales. In addition, we find that halo assembly bias,
in particular the dependence of clustering on halo shape, propagates to the
clustering of galaxies. We predict that this aspect of assembly bias should be
observable through the use of extensive group catalogues.Comment: 8 pages, 6 figures. Accepted for publication in MNRAS. Minor changes
relative to v1. Note: this is an revised and considerably extended
resubmission of http://arxiv.org/abs/1110.4888; please refer to the current
version rather than the old on
Matched filter optimization of kSZ measurements with a reconstructed cosmological flow field
We develop and test a new statistical method to measure the kinematic
Sunyaev-Zel'dovich (kSZ) effect. A sample of independently detected clusters is
combined with the cosmic flow field predicted from a galaxy redshift survey in
order to derive a matched filter that optimally weights the kSZ signal for the
sample as a whole given the noise involved in the problem. We apply this
formalism to realistic mock microwave skies based on cosmological -body
simulations, and demonstrate its robustness and performance. In particular, we
carefully assess the various sources of uncertainty, cosmic microwave
background primary fluctuations, instrumental noise, uncertainties in the
determination of the velocity field, and effects introduced by miscentring of
clusters and by uncertainties of the mass-observable relation (normalization
and scatter). We show that available data (\plk\ maps and the MaxBCG catalogue)
should deliver a detection of the kSZ. A similar cluster catalogue
with broader sky coverage should increase the detection significance to . We point out that such measurements could be binned in order to
study the properties of the cosmic gas and velocity fields, or combined into a
single measurement to constrain cosmological parameters or deviations of the
law of gravity from General Relativity.Comment: 17 pages, 10 figures, 3 tables. Submitted to MNRAS. Comments are
welcome
Well-posedness and stability results for the Gardner equation
In this article we present local well-posedness results in the classical
Sobolev space H^s(R) with s > 1/4 for the Cauchy problem of the Gardner
equation, overcoming the problem of the loss of the scaling property of this
equation. We also cover the energy space H^1(R) where global well-posedness
follows from the conservation laws of the system. Moreover, we construct
solitons of the Gardner equation explicitly and prove that, under certain
conditions, this family is orbitally stable in the energy space.Comment: 1 figure. Accepted for publication in Nonlin.Diff Eq.and App
Extending the halo mass resolution of -body simulations
We present a scheme to extend the halo mass resolution of N-body simulations
of the hierarchical clustering of dark matter. The method uses the density
field of the simulation to predict the number of sub-resolution dark matter
haloes expected in different regions. The technique requires as input the
abundance of haloes of a given mass and their average clustering, as expressed
through the linear and higher order bias factors. These quantities can be
computed analytically or, more accurately, derived from a higher resolution
simulation as done here. Our method can recover the abundance and clustering in
real- and redshift-space of haloes with mass below at to better than 10%. We demonstrate the
technique by applying it to an ensemble of 50 low resolution, large-volume
-body simulations to compute the correlation function and covariance matrix
of luminous red galaxies (LRGs). The limited resolution of the original
simulations results in them resolving just two thirds of the LRG population. We
extend the resolution of the simulations by a factor of 30 in halo mass in
order to recover all LRGs. With existing simulations it is possible to generate
a halo catalogue equivalent to that which would be obtained from a -body
simulation using more than 20 trillion particles; a direct simulation of this
size is likely to remain unachievable for many years. Using our method it is
now feasible to build the large numbers of high-resolution large volume mock
galaxy catalogues required to compute the covariance matrices necessary to
analyse upcoming galaxy surveys designed to probe dark energy.Comment: 11 pages, 7 Figure
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