58,004 research outputs found
The importance of target audiences in the design of training actions
This paper describes the process of definition, conceptualization and implementation of a business course addressed for logistic and industrial managers. This course was designed using a blended methodology, with training in classroom, visits to enterprises and self- study, supported by an eLearning platform. The aim of this work is to create an opportunity to reflect about the decisions and strategies implemented and point future developments
Newtonian Perturbations on Models with Matter Creation
Creation of Cold Dark Matter (CCDM) can macroscopically be described by a
negative pressure, and, therefore, the mechanism is capable to accelerate the
Universe, without the need of an additional dark energy component. In this
framework we discuss the evolution of perturbations by considering a
Neo-Newtonian approach where, unlike in the standard Newtonian cosmology, the
fluid pressure is taken into account even in the homogeneous and isotropic
background equations (Lima, Zanchin and Brandenberger, MNRAS {\bf 291}, L1,
1997). The evolution of the density contrast is calculated in the linear
approximation and compared to the one predicted by the CDM model. The
difference between the CCDM and CDM predictions at the perturbative
level is quantified by using three different statistical methods, namely: a
simple -analysis in the relevant space parameter, a Bayesian
statistical inference, and, finally, a Kolmogorov-Smirnov test. We find that
under certain circumstances the CCDM scenario analysed here predicts an overall
dynamics (including Hubble flow and matter fluctuation field) which fully
recovers that of the traditional cosmic concordance model. Our basic conclusion
is that such a reduction of the dark sector provides a viable alternative
description to the accelerating CDM cosmology.Comment: Physical Review D in press, 10 pages, 4 figure
CMB statistical isotropy confirmation at all scales using multipole vectors
We present an efficient numerical code and conduct, for the first time, a
null and model-independent CMB test of statistical isotropy using Multipole
Vectors (MVs) at all scales. Because MVs are insensitive to the angular power
spectrum , our results are independent from the assumed cosmological
model. We avoid a posteriori choices and use pre-defined ranges of scales
, and in our analyses. We
find that all four masked Planck maps, from both 2015 and 2018 releases, are in
agreement with statistical isotropy for , . For
we detect anisotropies but this is indicative of simply the
anisotropy in the noise: there is no anisotropy for and an
increasing level of anisotropy at higher multipoles. Our findings of no
large-scale anisotropies seem to be a consequence of avoiding \emph{a
posteriori} statistics. We also find that the degree of anisotropy in the full
sky (i.e. unmasked) maps vary enormously (between less than 5 and over 1000
standard deviations) among the different mapmaking procedures and data
releases.Comment: v4: additional analysis which increased statistical sensitivity,
including new plots and tables; extended discussion; 15 pages, 14 figures, 7
tables. Matches published versio
A universal approach for drainage basins
Drainage basins are essential to Geohydrology and Biodiversity. Defining
those regions in a simple, robust and efficient way is a constant challenge in
Earth Science. Here, we introduce a model to delineate multiple drainage basins
through an extension of the Invasion Percolation-Based Algorithm (IPBA). In
order to prove the potential of our approach, we apply it to real and
artificial datasets. We observe that the perimeter and area distributions of
basins and anti-basins display long tails extending over several orders of
magnitude and following approximately power-law behaviors. Moreover, the
exponents of these power laws depend on spatial correlations and are invariant
under the landscape orientation, not only for terrestrial, but lunar and
martian landscapes. The terrestrial and martian results are statistically
identical, which suggests that a hypothetical martian river would present
similarity to the terrestrial rivers. Finally, we propose a theoretical value
for the Hack's exponent based on the fractal dimension of watersheds,
. We measure for Earth, which is close to
our estimation of . Our study suggests that Hack's law can
have its origin purely in the maximum and minimum lines of the landscapes.Comment: 20 pages, 6 Figures, and 1 Tabl
Transmission coefficient and two-fold degenerate discrete spectrum of spin-1 bosons in a double-step potential
The scattering of spin-1 bosons in a nonminimal vector double-step potential
is described in terms of eigenstates of the helicity operator and it is shown
that the transmission coefficient is insensitive to the choice of the
polarization of the incident beam. Poles of the transmission amplitude reveal
the existence of a two-fold degenerate spectrum. The results are interpreted in
terms of solutions of two coupled effective Schr\"{o}dinger equations for a
finite square well with additional -functions situated at the borders.Comment: arXiv admin note: substantial text overlap with arXiv:1203.119
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