4,365 research outputs found

    On the void explanation of the Cold Spot

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    The integrated Sachs-Wolfe (ISW) contribution induced on the cosmic microwave background by the presence of a supervoid as the one detected by Szapudi et al. (2015) is reviewed in this letter in order to check whether it could explain the Cold Spot (CS) anomaly. Two different models, previously used for the same purpose, are considered to describe the matter density profile of the void: a top hat function and a compensated profile produced by a Gaussian potential. The analysis shows that, even enabling ellipticity changes or different values for the dark-energy equation of state parameter ω\omega, the ISW contribution due to the presence of the void does not reproduce the properties of the CS. Finally, the probability of alignment between the void and the CS is also questioned as an argument in favor of a physical connection between these two phenomena

    Motorized circular rail with RGB-D sensor on cart for physical rehabilitation

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    This paper introduces a motorized circular rail managing the movement of two carts equipped with an RGB-D sensor each. The proposal is aimed at continuously tracking a person who is undergoing a series of physical rehabilitation exercises from two different viewpoints to monitor if the exercises are being correctly conducted. More concretely, this work offers all details of the trajectory calculation for safe movement of both carts on the motorized circular rail. Then, two study cases are presented to show the efficiency of the control algorithms implemented.AEI - Agencia Estatal de Investigação(TIN2016-79100-R)This work was partially supported by Ministerio de Ciencia, Innovación y Universidades, Agencia Estatal de Investigación (AEI) / European Regional Development Fund (FEDER, UE) under DPI2016-80894-R and TIN2016-79100-R grants

    Genetic improvement and management of small populations

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    Ponencia publicada en ITEA, vol.104La gestión genética de poblaciones pequeñas, cualquiera que sea el objetivo perseguido, viene condicionada precisamente por su tamaño. Hoy en día, la distinción entre programas de conservación y programas de selección tiende a difuminarse ya que en ambos tipos de programas hay que prestar atención tanto al aumento de la consanguinidad como a la mejora o mantenimiento de algunos caracteres de interés. Para el mantenimiento de la diversidad el criterio que debe seguirse es el de maximizar el censo efectivo. Para ello durante las últimas décadas se han desarrollado unas reglas sencillas aunque también existe una solución sofisticada y al parecer óptima. En programas de selección existen también reglas sencillas y una solución óptima aunque en este caso la solución implica también la consideración del progreso genético deseado. El diseño de apareamientos óptimos, aunque es más complejo desde el punto de vista teórico, tiene también una respuesta práctica satisfactoria.The genetic management of small populations, irrespective of the objective pursued, it is conditioned by their census. Actually the distinction between conservation and selection programmes tends to vanish because in both types of programmes attention should be paid to the increase of inbreeding and to the maintenance or improvement of some traits of interest. To maintain genetic diversity the criterion to follow is to maximize the effective population size. For this purpose several simple rules have been developed during the last decades although there exist also a sophisticated solution, probably optimal. For selection programmes there are also simple rules and an optimal solution although now the desired genetic progress should be included. The design of optimal mating systems, although it presents more problems from a theoretical point of view, it has also a reasonable practical solution

    Practical implementation of optimal management strategies in conservation programmes: a mate selection method

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    The maintenance of genetic diversity is, from a genetic point of view, a key objective of conservation programmes. The selection of individuals contributing offspring and the decision of the mating scheme are the steps on which managers can control genetic diversity, specially on ‘ex situ’ programmes. Previous studies have shown that the optimal management strategy is to look for the parents’ contributions that yield minimum group coancestry (overall probability of identity by descent in the population) and, then, to arrange mating couples following minimum pairwise coancestry. However, physiological constraints make it necessary to account for mating restrictions when deciding the contributions and, therefore, these should be implemented in a single step along with the mating plan. In the present paper, a single-step method is proposed to optimise the management of a conservation programme when restrictions on the mating scheme exist. The performance of the method is tested by computer simulation. The strategy turns out to be as efficient as the two-step method, regarding both the genetic diversity preserved and the fitness of the population

    Aplicación práctica de estrategias de manejo óptimo en programas de conservación: un método de selección de apareamientos

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    The maintenance of genetic diversity is, from a genetic point of view, a key objective of conservation programmes. The selection of individuals contributing offspring and the decision of the mating scheme are the steps on which managers can control genetic diversity, specially on "ex situ" programmes. Previous studies have shown that the optimal management strategy is to look for the parents’ contributions that yield minimum group coancestry (overall probability of identity by descent in the population) and, then, to arrange mating couples following minimum pairwise coancestry. However, physiological constraints make it necessary to account for mating restrictions when deciding the contributions and, therefore, these should be implemented in a single step along with the mating plan. In the present paper, a single–step method is proposed to optimise the management of a conservation programme when restrictions on the mating scheme exist. The performance of the method is tested by computer simulation. The strategy turns out to be as efficient as the two–step method, regarding both the genetic diversity preserved and the fitness of the population.El mantenimiento de la diversidad genética es, desde un punto de vista genético, un objetivo fundamental en programas de conservación. La selección de los individuos que dejarán descendientes y la decisión del esquema de apareamiento son los pasos en los que el conservador puede controlar la evolución de la diversidad, especialmente en programas "ex situ ". Se ha demostrado que la estrategia óptima consiste en buscar las contribuciones de los reproductores que den el mínimo parentesco global (probabilidad de identidad por descendencia de la población) y, posteriormente, determinar las parejas utilizando el método de apareamientos de mínimo parentesco. Sin embargo limitaciones fisiológicas y reproductivas pueden impedir que los apareamientos propuestos se lleven a cabo. Por esta razón, sugerimos la aplicación de un procedimiento que decida las contribuciones y el diseño de apareamientos en un solo paso. Mediante simulación con ordenador comparamos la eficiencia de dicho método frente al diseño óptimo en dos etapas. El procedimiento resultó ser tan eficiente como el método en dos pasos, tanto en el mantenimiento de variabilidad genética como en los niveles de eficacia biológica de la población

    Exploring two-spin internal linear combinations for the recovery of the CMB polarization

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    We present a methodology to recover cosmic microwave background (CMB) polarization in which the quantity P=Q+iUP = Q+ iU is linearly combined at different frequencies using complex coefficients. This is the most general linear combination of the QQ and UU Stokes parameters which preserves the physical coherence of the residual contribution on the CMB estimation. The approach is applied to the internal linear combination (ILC) and the internal template fitting (ITF) methodologies. The variance of PP of the resulting map is minimized to compute the coefficients of the linear combination. One of the key aspects of this procedure is that it serves to account for a global frequency-dependent shift of the polarization phase. Although in the standard case, in which no global E-B transference depending on frequency is expected in the foreground components, minimizing P2\left\langle |P|^2\right\rangle is similar to minimizing Q2\left\langle Q^2\right\rangle and U2\left\langle U^2\right\rangle separately (as previous methodologies proceed), multiplying QQ and UU by different coefficients induces arbitrary changes in the polarization angle and it does not preserve the coherence between the spinorial components. The approach is tested on simulations, obtaining a similar residual level with respect to the one obtained with other implementations of the ILC, and perceiving the polarization rotation of a toy model with the frequency dependence of the Faraday rotation.Comment: 14 pages, 8 figures, 2 tables. Accepted for publication in MNRA

    Radial derivatives as a test of pre-Big-Bang events on the Planck data

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    Although the search for azimutal patterns in cosmological surveys is useful to characterise some effects depending exclusively on an angular distance within the standard model, they are considered as a key distinguishing feature of some exotic scenarios, such as bubble collisions or conformal cyclic cosmology (CCC). In particular, the CCC is a non-stardard framework which predicts circular patterns on the CMB intensity fluctuations. Motivated by some previous works which explore the presence of radial gradients, we apply a methodology based on the radial derivatives to the latest release of \textit{Planck} data. The new approach allows exhaustive studies to be performed at all sky directions at a HEALPix resolution of Nside=1024N_{\mathrm{side}} = 1024. Specifically, two different analyses are performed focusing on weight functions in both small (up to a 55-degree radius) and large scales. We present a comparison between our results and those shown by An et al. (2017), and An et al. (2018). In addition, a possible polarization counterpart of these circular patterns is also analysed for the most promising case. Taking into account the limitations to characterize the significance of the results, including the possibility of suffering a look-elsewhere effect, no strong evidence of the kind of circular patterns expected from CCC is found in the \textit{Planck} data for either the small or the large scales.Comment: 8 figures, 4 table

    A novel heat-pulse probe for measuring soil thermal conductivity: Field test under different tillage practices

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    Accurate soil thermal conductivity (λ) measurements are needed in experimental agri-environmental research. This study design and build of new heat-pulse probe (HPP) based on transient state technology to measure λ. The HPP consists of three main components: an electronic control system, a measurement chamber, and sample rings. The performance of the new HPP for in-situ λ measurements is compared to estimates from measurable soil physical properties (pedotransfer function). Tests were conducted in clay loam and loam soils at three depths. λ measurements by the HPP were affected by tillage practice, fertilizer treatment, soil depth, and soil type. No significant differences in λ measurements by the HPP and estimates from a pedotransfer function were found between tillage practices. There were positive correlations between their values at three soil depths: R2 = 0.92 at 0–5 cm depth, and R2 = 0.88 at both 5–10 and 10–15 cm depths. The standard deviation from the HPP measurements were 0.061, 0.077, and 0.080 W·m−1·K−1 at 0–5, 5–10, and 10–15 cm depths, respectively. In contrast, the pedotransfer function estimates had standard deviations of 0.085, 0.660, and 0.083 W·m−1·K−1, respectively. It was found that conventional tillage increases temperature flow in soils compared to no-tillage because of decreasing soil bulk density (ρb) and consequently higher porosity. The proposed HPP is a low-cost and energy-efficient device, with wide applicability under a range of conditions. It is highly recommended for measuring λ clay loam and loam soils; however, more research is needed to determine its value with other soil types
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