2,815 research outputs found

    Non-Markovian qubit dynamics in a circuit-QED setup

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    We consider a circuit-QED setup that allows the induction and control of non-Markovian dynamics of a qubit. Non-Markovianity is enforced over the qubit by means of its direct coupling to a bosonic mode which is controllably coupled to other qubit-mode system. We show that this configuration can be achieved in a circuit-QED setup consisting of two initially independent superconducting circuits, each formed by one charge qubit and one transmission-line resonator, which are put in interaction by coupling the resonators to a current-biased Josephson junction. We solve this problem exactly and then proceed with a thorough investigation of the emergent non-Markovianity in the dynamics of the qubits. Our study might serve the context for a first experimental assessment of non-Markovianity in a multi-element solid-state device.Comment: 8 pages, 7 figures, slightly changed titl

    Sustainable Pastures for the High Altitude Andean Tropics of Colombia

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    Dairy production systems in the high altitude Andean region of Colombia (\u3e2.600 m.a.s.l.) use large amounts of nitrogen (N) fertilisation. Due to the inefficient use of N by the grass, it contaminates surface and ground water resulting in the eutrophication of lakes and rivers. It contributes to increased atmospheric NOx, greenhouse gas and acid rain. Therefore, the effect of different species of grasses mixed with Lotus corniculatuson N soil balance was evaluated

    Resonance enhancement of particle production during reheating

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    We found a consistent equation of reheating after inflation, which shows that for small quantum fluctuations the frequencies of resonance are slighted different from the standard ones. Quantum interference is taken into account and we found that at large fluctuations the process mimics very well the usual parametric resonance but proceed in a different dynamical way. The analysis is made in a toy quantum mechanical model and we discuss further its extension to quantum field theory.Comment: 4 pages, 4 figures(eps), using RevTe

    Reconstruction of tree branching structures from UAV-LiDAR data

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    The reconstruction of tree branching structures is a longstanding problem in Computer Graphics which has been studied over several data sources, from photogrammetry point clouds to Terrestrial and Aerial Laser Imaging Detection and Ranging technology. However, most data sources present acquisition errors that make the reconstruction more challenging. Among them, the main challenge is the partial or complete occlusion of branch segments, thus leading to disconnected components whether the reconstruction is resolved using graph-based approaches. In this work, we propose a hybrid method based on radius-based search and Minimum Spanning Tree for the tree branching reconstruction by handling occlusion and disconnected branches. Furthermore, we simplify previous work evaluating the similarity between ground-truth and reconstructed skeletons. Using this approach, our method is proved to be more effective than the baseline methods, regarding reconstruction results and response time. Our method yields better results on the complete explored radii interval, though the improvement is especially significant on the Ground Sampling Distance In terms of latency, an outstanding performance is achieved in comparison with the baseline method.Junta de Andalucia 1381202-GEU PYC20-RE-005-UJAEuropean Commission Spanish Government PID2021-126339OB-I00 FPU17/01902 FPU19/0010

    A paper-based polystyrene/nylon Janus platform for the microextraction of UV filters in water samples as proof-of-concept

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    A new mix-mode cellulose-based sorptive phase is described that combines two different polymeric domains (i.e., nylon and polystyrene), thus providing simultaneous hydrophilic and hydrophobic features as a result. By analogy with Janus materials, the new paper-based sorptive phase has been named paper-based polystyrene/nylon Janus-platform (P-Ps/Ny-JP). The main advantages of the proposed P-Ps/Ny-JP are the sustainability, simplicity in synthesis, and low cost of this extraction device. The main parameters affecting the synthesis (i.e., coating procedure and polymers proportion) have been studied, and the resulting material has been characterized via scanning electron microscopy and infrared spectroscopy. As a proof-of-concept, the simultaneous extraction of fourteen UV filters of a wide range of polarity, with log P values ranging from − 0.234 to 16.129, from water samples and their determination by liquid chromatography-tandem mass spectrometry (LC–MS/MS) has been performed. The proposed methodology enables the determination of these chemicals with limits of detection from 12 to 71 ng L−1, and the precision, expressed as a relative standard deviation, was below 15%. The extraction device was applied to the analysis of real water samples likely to contain UV filters (i.e., two private swimming pool water and one seawater) and the recovery values were in the range 73–121%

    Deshidratación de etanol empleando líquidos iónicos de naturaleza prótica

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    En este trabajo se presenta el estudio experimental de la deshidratación de etanol empleando líquidos iónicos de naturaleza prótica, con el objetivo de determinar un líquido iónico prótico efectivo en este proceso de separación. Para ello se sintetizaron tres líquidos iónicos (formiato de 2-hidroxietilamonio, lactato de2-hidroxietilamonio y propionato de 2-hidroxietilamonio) y se determinaron sus propiedades críticas y densidad apartir de métodos de contribución de grupos. Además se confirmó la naturaleza de los líquidos iónicos obtenidos mediante espectrometría infrarrojo de transformada de Fourier (FTIR). La destilación extractiva con los líquidos obtenidos se llevó a cabo en un sistema de destilación simple y se analizó el destilado por las técnicas analíticas de densimetría digital (para determinar porcentaje volumétrico) y cromatografía de gases (para determinar componentes mayoritarios). Los tres líquidos utilizados en el proceso de separación mostraron resultados favorables, o sea se obtuvo un aumento en la concentración de etanol en la fase vapor. Los líquidos iónicos formiato y propionato de 2-hidroxietilamonio presentaron comportamientos similares, pues lograron un aumento más marcado en la concentración de etanoly el lactato de 2-hidroxietilamonio es el que menos influyó en el proceso de separación.

    A study of local approximation for polarization potentials

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    We discuss the derivation of an equivalent \textit{l}-independent polarization potential for use in the optical Schr\"{o}dinger equation that describes the elastic scattering of heavy ions. Three diffferent methods are used for this purpose. Application of our theory to the low energy scattering of the halo nucleus 11^{11}Li from a 12^{12}C target is made. It is found that the notion of \textit{l}-independent polarization potential has some validity but can not be a good substitute for the \textit{l}-dependent local equivalent Feshbach polarization potential.Comment: 8 pages, 4 figure

    Arctocephalus australis, South American Fur Seal

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    El texto incluye una revisión taxonómica, el rango de distribución, información poblacional, ecológica, genética, amenazas y estado de conservación.Fil: Cárdenas Alayza, S.. No especifica;Fil: Oliveira, L.. No especifica;Fil: Crespo, Enrique Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; Argentin

    Some Remarks on Oscillating Inflation

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    In a recent paper Damour and Mukhanov describe a scenario where inflation may continue during the oscillatory phase. This effect is possible because the scalar field spends a significant fraction of each period of oscillation on the upper part of the potential. Such additional period of inflation could push perturbations after the slow roll regime to observable scales. Although in this work we show that the small region of the Damour-Mukhanov parameter q gives the main contribution to oscillating inflation, it was not satisfactory understood until now. Furthermore, it gives an expression for the energy density spectrum of perturbations, which is well behaved in the whole physical range of q .Comment: 4 pages including figures caption, 3 ps-figures. To appear in Phys. Rev.

    Consumer behavior in the disposition of disliked gifts

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    La entrega y recepción de regalos ha sido investigada en diversos campos, incluido el comportamiento del consumidor. El presente estudio analiza el comportamiento de disposición de regalos no gustados de una muestra de 958 individuos adultos en Ecuador (un país latinoamericano). A nivel descriptivo, el método de disposición más frecuente de este tipo de regalos es el almacenamiento. A nivel multivariante, la edad, el género, el ingreso y el colectivismo del receptor; el impacto del regalo en la relación dador-receptor; el tiempo transcurrido desde la recepción del regalo; el precio estimado del regalo y si el regalo fue o no usado; predicen el método de disposición de los regalos no gustados. Adicionalmente se discuten estos resultados y sus implicaciones.Giving and receiving gifts have been investigated in many fields of study, including consumer behavior. This study analyzes the behavior of a sample of 958 adults from Ecuador (a Latin American country), focusing on the disposition of gifts that recipients do not like. At the descriptive level, the most common disposition method of these gifts is storage. At the multivariate level, age, gender, income, and collectivism of receiver; the gift impact on the giver-receiver relationship; the time elapsed since the receiving of the gift; the estimated price of the gift and whether the gift was used or not predict the disposition method of the disliked gift. These results and their implications are discussed
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