2,814 research outputs found
Non-Markovian qubit dynamics in a circuit-QED setup
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
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
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
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
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
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
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 Li from a 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
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
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
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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