5,659 research outputs found

    Daylight Spectrum Index: A New Metric to Assess the Affinity of Light Sources with Daylighting

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    The current scenario of colorimetry shows a wide variety of different metrics which do not converge in the assessment of the color rendering of light sources. The limitations of the Color Rendering Index have promoted the emergence of new metrics, such as the Color Quality Scale. As in the case of the previous metric, these new concepts are based on the analysis of the deviation of different color samples in a color space, contrasting the results with those obtained with a light source reference, which can vary depending on the color temperature. Within this context, the Daylight Spectrum Index is proposed. This new concept aims to determine the affinity with daylighting of electric light sources, comparing the resulting spectral power distributions of the lamps studied and that observed under natural light. The affinity of an electric light source with daylighting allows for lower energy consumption due to the better performance of human vision. The new metric proposed is evaluated following the results obtained from 80 surveys, demonstrating the usefulness of this new concept in the quantification of color rendering of LED lamps and the affinity of electric light sources with daylighting.Government of Spain BIA2017-86997-

    Monitoring resistance of Cydia pomonella (L.) Spanish field populations to new chemical insecticides and the mechanisms involved

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    BACKGROUND: A widespread resistance of Cydia pomonella to organophosphates was demonstrated in populations from the Spanish Ebro Valley area that showed high levels of enzymatic detoxification. To determine the efficacy of new insecticides, neonate larvae bioassays were carried out on twenty field codling moth populations collected from three different Spanish apple production areas. Synergist bioassays were performed to detect the enzymatic mechanisms involved. RESULTS: The least active ingredients were methoxyfenozide, with 100% of the populations showing significantly lower mortality than the susceptible strain, and lambda-cyhalothrin, with very high resistant ratios (872.0 for the most resistant field population). Approximately 50% of the populations were resistant or tolerant to thiacloprid. By contrast, tebufenozide was very effective in all the field populations, as was chlorpyrifos-ethyl despite its widespread use during the last few years. Indoxacarb, spinosad and chlorantraniliprole also provided high efficacy, as did emamectin and spinetoram, which are not yet registered in Spain. CONCLUSION: The resistant Spanish codling moth populations can be controlled using new reduced-risk insecticides. The use of synergists showed the importance of the concentration applied and the difficulty of interpreting the results in field populations that show multiple resistance to different active ingredients.The authors would like to express their sincere thanks to the fruit growers who gave us access to their orchards and to the grower advisors of the areas (plant defense area technicians), who helped identify the best orchards for the assays, and Mònica Pérez for her technical help. This study was partially supported by grants AGL2013-49164 and AGL2016-77373 of the Spanish Ministry for Science and Innovation and by the CERCA Programme / Generalitat de Catalunya

    Demand shocks and trade balance dynamics

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    This paper studies the current account dynamics in the G-7 countries plus Spain. We estimate a SVAR model which allows us to identify three different shocks: supply shocks, real demand shocks and nominal shocks. We use a different identification procedure from previous work based on a microfounded stochastic open-economy model in which the real exchange rate is a determinant of the Phillips curve. Estimates from a structural VAR show that real demand shocks explain most of the variability of current account imbalances, whereas, contrary to previous findings, nominal shocks play no role. The results we obtain are consistent with the predictions of a widely set of open-economy models and illustrate that demand policies are the main responsible of trade imbalances.Current account, SVAR

    Uncertainty about the Persistence of Cost-Push Shocks and the Optimal Reaction of the Monetary Authority.

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    In this paper we formalize the uncertainty about the persistence of cost-push shocks using an open economy optimal control model with Markov regime-switching and robust control. The latter is used in only one of the regimes producing relatively more persistent cost-push shocks in that regime. Conditional on being in the regime with relatively less persistence, we obtain two main results: a) underestimating the probability of switching to the regime with relatively more persistent cost-push shocks causes higher welfare losses than its overestimation; and b) the welfare losses associated with either underestimation or overestimation of such probability increase with the size of the penalty on inflation deviations from its target. Keywords: Model uncertainty, Robustness, Markov regime-switching, Monetary policy, Inflation targeting.Model uncertainty, Robustness, Markov regime-switching, Monetary policy, Inflation targeting

    Target-site mutations (AChE and kdr), and PSMO activity in codling moth (Cydia pomonella (L.) (Lepidoptera: Tortricidae)) populations from Spain

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    Codling moth, Cydia pomonella (L.) is a key pest of global importance that affects apple fruit production and whose populations have developed resistance to insecticides in many apple production areas. In Spain, enhanced cytochrome P450 polysubstrate monooxygenase (PSMO) activity is the main mechanism involved in insecticide detoxification by codling moth, although acetylcholinesterase (AChE) target site mutations have been described in two populations. However, the extent of AChE and knockdown resistance (kdr) mutations in Spain is unknown. To assess the actual occurrence of AChE and kdr mutations concurrently with the frequency of moths with PSMO enhanced activity (R-PSMO), 32 Spanish field populations from four apple-growing areas of Spain and two susceptible laboratory strains were evaluated. R-PSMO was significantly higher in 23 chemically treated field populations from Extremadura, Catalonia and Aragon, with proportions that varied between 25% and 90%, but no significant differences among strains and the non-chemically treated orchards (organic or abandoned) were observed. The AChE mutation (F290V) was detected in all field populations from Catalonia (n=21) and in three field populations from Aragon (n=5), with resistant phenotype proportions varying from 34.2% to 97.5% and from 7.2% to 65% in Catalonia and Aragon, respectively. In addition, the kdr mutation (L1014F) was detected in twelve Catalonian field populations, at rates of incidence ranging between 2.6% and 56.8%. A positive correlation between R-PSMO and AChE mutation was found. The origin of the mutations and their ability to persist and spread in field populations with different management systems is discussed.The authors thank the fruit growers and pest control advisors of the different Spanish apple-growing areas for their help in accessing and identifying apple orchards and Mónica Pérez for her technical help. This work was funded by grant Fondo de Desarrollo Científico y Tecnológico, FONDECYT 11130599 (CONICYT), Chile, to M.A. Rodríguez, by grant AGL2013-49164 of the Spanish Ministry for Science and Innovation, to J. Avilla and D. Bosch, and by the CERCA Programme/Generalitat de Catalunya

    Seasonal dynamic factor analysis and bootstrap inference : application to electricity market forecasting

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    Year-ahead forecasting of electricity prices is an important issue in the current context of electricity markets. Nevertheless, only one-day-ahead forecasting is commonly tackled up in previous published works. Moreover, methodology developed for the short-term does not work properly for long-term forecasting. In this paper we provide a seasonal extension of the Non-Stationary Dynamic Factor Analysis, to deal with the interesting problem (both from the economic and engineering point of view) of long term forecasting of electricity prices. Seasonal Dynamic Factor Analysis (SeaDFA) allows to deal with dimensionality reduction in vectors of time series, in such a way that extracts common and specific components. Furthermore, common factors are able to capture not only regular dynamics (stationary or not) but also seasonal one, by means of common factors following a multiplicative seasonal VARIMA(p,d,q)×(P,D,Q)s model. Besides, a bootstrap procedure is proposed to be able to make inference on all the parameters involved in the model. A bootstrap scheme developed for forecasting includes uncertainty due to parameter estimation, allowing to enhance the coverage of forecast confidence intervals. Concerning the innovative and challenging application provided, bootstrap procedure developed allows to calculate not only point forecasts but also forecasting intervals for electricity prices

    Demand Shocks and Trade Balance Dynamics

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    This paper studies the current account dynamics in the G-7 countries plus Spain. We estimate a SVAR model which allows us to identify three different shocks: supply shocks, real demand shocks and nominal shocks. We use a different identification procedure from previous work based on a microfounded stochastic open-economy model in which the real exchange rate is a determinant of the Phillips curve. Estimates from a structural VAR show that real demand shocks explain most of the variability of current account imbalances, whereas, contrary to previous findings, nominal shocks play no role. The results we obtain are consistent with the predictions of a widely set of open-economy models and illustrate that demand policies are the main responsible of trade imbalances.Current account, SVAR.

    Identificat un nou mecanisme pel qual un patogen genera resistència als antibiòtics

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    Els pacients hospitalitzats, especialment els malalts crítics, són susceptibles a l'acció del microorganisme Acinetobacter baumannii, que pot provocar infeccions greus com septicèmia, pneumònia o meningitis i que té una gran capacitat de desenvolupar resistències a pràcticament tots els antibiòtics en ús clínic. Investigadors de la UAB conjuntament amb l'Hospital d'A Coruña i amb la col∙laboració d'una universitat australiana han descobert un nou mecanisme pel qual aquest patogen és capaç d'adquirir resistència als antibiòtics.Los pacientes hospitalizados, especialmente los enfermos críticos, son susceptibles a la acción del microorganismo Acinetobacter baumannii, que puede provocar infecciones graves como septicemia, neumonía o meningitis y que tiene una gran capacidad de desarrollar resistencias a prácticamente todos los antibióticos en uso clínico. Investigadores de la UAB conjuntamente con el Hospital de A Coruña y con la colaboración de una universidad australiana han descubierto un nuevo mecanismo por el cual este patógeno es capaz de adquirir resistencia a los antibióticos

    On the optimaL response of q-vortex

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    Wingtip vortices represent a hazard for the stability of the following airplane in airport highways. These flows have been usually modeled as swirling jets/wakes, which are known to be highly unstable and susceptible to breakdown at high Reynolds numbers for certain flow conditions, but different to the ones present in real flying airplanes. A very recent study based on Direct Numerical Simulations (DNS) shows that a large variety of helical responses can be excited and amplified when a harmonic inlet forcing is imposed. In this work, the optimal response of q-vortex (both axial vorticity and axial velocity can be modeled by a Gaussian profile) is studied by considering the time-harmonically forced problem with a certain frequency ω. We first reproduce Guo and Sun’s results for the Lamb-Oseen vortex (no axial flow) to validate our numerical code. In the axisymmetric case m = 0, the system response is the largest when the input frequency is null. The axial flow has a weak influence in the response for any axial velocity intensity. We also consider helical perturbations |m| = 1. These perturbations are excited through a resonance mechanism at moderate and large wavelengths as it is shown in Figure 1. In addition, Figure 2 shows that the frequency at which the optimal gain is obtained is not a continuous function of the axial wavenumber k. At smaller wavelengths, large response is excited by steady forcing. Regarding the axial flow, the unstable response is the largest when the axial velocity intensity, 1/q, is near to zero. For perturbations with higher azimuthal wavenumbers |m| > 1, the magnitudes of the response are smaller than those for helical modes. In order to establish an alternative validation, DNS has been carried out by using a pseudospectral Fourier formulation finding a very good agreement.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Contextual control of conditional discrimination of the own behavior in pigeons

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    An experiment in which a pigeon was trained in contextual discrimination of its own behavior was carried out. When the experimental chamber was illuminated with a constant light, the pigeon had to peck on a red (or green) key in the sample component after having been pecking to the left (or to the right). When the chamber was illuminated with an intermittent light, the reinforced sample-comparison sequences were the opposite. The subject learned the task in about 40 sessions and maintained high correct response ratios even though the reinforcement probability decreased from 1 to 0.2 after each correct trial. The results are discussed in terms of the kind of discriminative rule and the kind of hierarchic structure involved in the task.Se llevó a cabo un experimento en el que se entrenó a una paloma en una discriminación contextual de su propia conducta. Cuando estaba iluminada la luz general de la cámara experimental de manera constante, la paloma tenía que picar una tecla roja (o verde) tras haber estado picoteando a la izquierda (o derecha) en el componente de muestra. Cuando la luz general de la cámara se iluminaba de manera parpadeante, las secuencias reforzadas muestra-comparación fueron las contrarias. El sujeto aprendió la tarea en unas 40 sesiones y siguió manteniendo unos altos índices de acierto a pesar de bajar la probabilidad de reforzamiento tras cada ensayo correcto de 1 a 0.2. Los resultados se discuten en relación con el tipo de regla discriminativa y de estructura jerárquica involucradas en esta tarea
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