68,008 research outputs found

    The importance of target audiences in the design of training actions

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    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

    The Penna model for biological ageing on a lattice: spatial consequences of child-care

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    We introduce a square lattice into the Penna bit-string model for biological ageing and study the evolution of the spatial distribution of the population considering different strategies of child-care. Two of the strategies are related to the movements of a whole family on the lattice: in one case the mother cannot move if she has any child younger than a given age, and in the other case if she moves, she brings these young children with her. A stronger condition has also been added to the second case, considering that young children die with a higher probability if their mothers die, this probability decreasing with age. We show that a highly non uniform occupation can be obtained when child-care is considered, even for an uniform initial occupation per site. We also compare the standard survival rate of the model with that obtained when the spacial lattice is considered (without any kind of child-care).Comment: 8 pages, 6 Postscript figure

    Newtonian Perturbations on Models with Matter Creation

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    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 Λ\LambdaCDM model. The difference between the CCDM and Λ\LambdaCDM predictions at the perturbative level is quantified by using three different statistical methods, namely: a simple χ2\chi^{2}-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 Λ\LambdaCDM cosmology.Comment: Physical Review D in press, 10 pages, 4 figure

    CMB statistical isotropy confirmation at all scales using multipole vectors

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    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 CℓC_\ell, our results are independent from the assumed cosmological model. We avoid a posteriori choices and use pre-defined ranges of scales ℓ∈[2,30]\ell\in[2,30], ℓ∈[2,600]\ell\in[2,600] and ℓ∈[2,1500]\ell\in[2,1500] in our analyses. We find that all four masked Planck maps, from both 2015 and 2018 releases, are in agreement with statistical isotropy for ℓ∈[2,30]\ell\in[2,30], ℓ∈[2,600]\ell\in[2,600]. For ℓ∈[2,1500]\ell\in[2,1500] we detect anisotropies but this is indicative of simply the anisotropy in the noise: there is no anisotropy for ℓ<1300\ell < 1300 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

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    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, γ=D/2\gamma=D/2. We measure γ=0.54±0.01\gamma=0.54 \pm 0.01 for Earth, which is close to our estimation of γ≈0.55\gamma \approx 0.55. 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
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