Relativistic Klein-Gordon charge effects by information-theoretic measures

The charge spreading of ground and excited states of Klein-Gordon particles moving in a Coulomb potential is quantitatively analyzed by means of the ordinary moments and the Heisenberg measure as well as by use of the most relevant information-theoretic measures of global (Shannon entropic power) and local (Fisher's information) types. The dependence of these complementary quantities on the nuclear charge Z and the quantum numbers characterizing the physical states is carefully discussed. The comparison of the relativistic Klein-Gordon and non-relativistic Schrodinger values is made. The non-relativistic limits at large principal quantum number n and for small values of Z are also reached.Comment: Accepted in New Journal of Physic

Breakdown of anomalous channeling with ion energy for accurate strain determination in gan-based heterostructures

The influence of the beam energy on the determination of strain state with ion channeling in GaN-based heterostructures (HSs) is addressed. Experimental results show that anomalous channeling may hinder an accurate analysis due to the steering effects at the HS interface, which are more intense at lower ion energies. The experimental angular scans have been well reproduced by Monte Carlo simulations, correlating the steering effects with the close encounter probability at the interface. Consequently, limitations in the determination of the strain state by ion channeling can be overcome by selecting the adequate beam energy

Tunable plasmonic resonance of gallium nanoparticles by thermal oxidation at low temperatures

This Accepted Manuscript is available for reuse under a CC BY-NC-ND 3.0 licence after the 12 month embargo period provided that all the terms of the licence are adhered toThe effect of the oxidation of gallium nanoparticles (Ga NPs) on their plasmonic properties is investigated. Discrete dipole approximation has been used to study the wavelength of the out-of-plane localized surface plasmon resonance in hemispherical Ga NPs, deposited on silicon substrates, with oxide shell (Ga2O3) of different thickness. Thermal oxidation treatments, varying temperature and time, were carried out in order to increase experimentally the Ga2O3 shell thickness in the NPs. The optical, structural and chemical properties of the oxidized NPs have been studied by spectroscopic ellipsometry, scanning electron microscopy, grazing incidence x-ray diffraction and x-ray photoelectron spectroscopy. A clear redshift of the peak wavelength is observed, barely affecting the intensity of the plasmon resonance. A controllable increase of the Ga2O3 thickness as a consequence of the thermal annealing is achieved. In addition, simulations together with ellipsometry results have been used to determine the oxidation rate, whose kinetics is governed by a logarithmic dependence. These results support the tunable properties of the plasmon resonance wavelength in Ga NPs by thermal oxidation at low temperatures without significant reduction of the plasmon resonance intensityThis research is supported by the MINECO (CTQ2014-53334-C2-2-R and MAT2016-80394-R) and Comunidad de Madrid (NANOAVANSENS ref. S2013/MIT-3029) projects. ARC acknowledges Ramón y Cajal program (under contract number RYC-2015-18047). FN acknowledges support from Marie Sklodowska-Curie grant agreement No 641899 from the European Union’s Horizon 2020 research and innovation programm

Thermal equilibrium and statistical thermometers in special relativity

There is an intense debate in the recent literature about the correct generalization of Maxwell's velocity distribution in special relativity. The most frequently discussed candidate distributions include the Juettner function as well as modifications thereof. Here, we report results from fully relativistic one-dimensional (1D) molecular dynamics (MD) simulations that resolve the ambiguity. The numerical evidence unequivocally favors the Juettner distribution. Moreover, our simulations illustrate that the concept of 'thermal equilibrium' extends naturally to special relativity only if a many-particle system is spatially confined. They make evident that 'temperature' can be statistically defined and measured in an observer frame independent way.Comment: version accepted for publication (5 pages), part of the introduction modified, new figures, additional reference

In-Line estimation of the standard colour index of citrus fruits using a computer vision system developed for a mobile platform

The final publication is available at Springer via http://dx.doi.org/10.1007/s11947-012-1015-2A key aspect for the consumer when it comes to deciding on a particular product is the colour. In order to make fruit available to consumers as early as possible, the collection of oranges and mandarins begins before they ripen fully and reach their typical orange colour. As a result, they are therefore subjected to certain degreening treatments, depending on their standard colour citrus index at harvest. Recently, a mobile platform that incorporates a computer vision system capable of pre-sorting the fruit while it is being harvested has been developed as an aid in the harvesting task. However, due to the restrictions of working in the field, the computer vision system developed for this machine is limited in its technology and processing capacity compared to conventional systems. This work shows the optimised algorithms for estimating the colour of citrus in-line that were developed for this mobile platform and its performance is evaluated against that of a spectrophotometer used as a reference in the analysis of colour in food. The results obtained prove that our analysis system predicts the colour index of citrus with a good reliability (R2 = 0.925) working in real time. Findings also show that it is effective for classifying harvested fruits in the field according to their colour. © 2012 Springer Science+Business Media New York.This work was partially funded by the INIA through research project RTA2009-00118-C02-01 with the support of European FEDER funds, and by the project PAID-05-11-2745, Vicerectorat d'Investigacio, Universitat Politecnica de Valencia.Vidal, A.; Talens Oliag, P.; Prats-Montalbán, JM.; Cubero García, S.; Albert Gil, FE.; Blasco Ivars, J. (2013). In-Line estimation of the standard colour index of citrus fruits using a computer vision system developed for a mobile platform. Food and Bioprocess Technology. 6(12):3412-3419. https://doi.org/10.1007/s11947-012-1015-2S34123419612Arzate-Vázquez, I., Chanona-Pérez, J. J., Perea-Flores, M. J., Calderón-Domínguez, G., Moreno-Armendáriz, M. A., Calvo, H., Godoy-Calderón, S., Quevedo, R., & Gutiérrez-López, G. (2011). Image processing applied to classification of avocado variety Hass (Persea americana Mill.) during the ripening process. Food and Bioprocess Technology, 4(7), 1307–1313.Blasco, J., Aleixos, N., Cubero, S., Gómez-Sanchis, J., & Moltó, E. (2009). Automatic sorting of satsuma (Citrus unshiu) segments using computer vision and morphological features. Computers and Electronics in Agriculture, 66, 1–8.Campbell, B. L., Nelson, R. G., Ebel, C. E., Dozier, W. A., Adrian, J. L., & Hockema, B. R. (2004). Fruit quality characteristics that affect consumer preferences for satsuma mandarins. HortScience, 39(7), 1664–1669.Cavazza, A., Corradini, C., Rinaldi, M., Salvadeo, P., Borromei, C., & Massini, R. (2012). Evaluation of pasta thermal treatment by determination of carbohydrates, furosine, and color indices. Food and Bioprocess Technology. doi: 10.1007/s11947-012-0906-6 . In-press.Cubero, S., Aleixos, N., Moltó, E., Gómez-Sanchis, J., & Blasco, J. (2011). Advances in machine vision applications for automatic inspection and quality evaluation of fruits and vegetables. Food and Bioprocess Technology, 4(4), 487–504.Cubero, S., Moltó, E., Gutiérrez, A., Aleixos, N., García-Navarrete, O. L., Juste, F., & Blasco, J. (2010). Real-time inspection of fruit on a mobile harvesting platform in field conditions using computer vision. Progress in Agricultural Engineering Science, 6, 1–16.Díaz, R., Faus, G., Blasco, M., Blasco, J., & Moltó, E. (2000). The application of a fast algorithm for the classification of olives by machine vision. Food Research International, 33, 305–309.DOGV (2006) Diari Oficial de la Comunitat Valenciana, 5346, 30321-30328.Gardner, J. L. (2007). Comparison of calibration methods for tristimulus colorimeters. Journal of Research of the National Institute of Standards and Technology, 112, 129–138.Hashim, N., Janius, R. B., Baranyai, L., Rahman, R. A., Osman, A., & Zude, M. (2011). Kinetic model for colour changes in bananas during the appearance of chilling injury symptoms. Food and Bioprocess Technology, 5(8), 2952–2963.HunterLab (2008): Applications note, 8(9), http://www.hunterlab.com/appnotes/an08_96a.pdf . Accessed September 2012.Hutchings, J. B., Luo, R., & Ji, W. (2002). Calibrated colour imaging analysis of food. In D. MacDougall (Ed.), Colour in Food (pp. 352–366). Cambridge: Woodhead Publishing.Jiménez-Cuesta MJ, Cuquerella J & Martínez-Jávega JM (1981) Determination of a color index for citrus fruit degreening. In Proc. of the International Society of Citriculture, Vol. 2, 750-753Kang, S. P., East, A. R., & Trujillo, F. J. (2008). Colour vision system evaluation of bicolour fruit: A case study with ‘B74’ mango. Postharvest Biology and Technology, 49, 77–85.Lang, C., & Hübert, T. (2011). A colour ripeness indicator for apples. Food and Bioprocess Technology, 5(8), 3244–3249.López-Camelo, A. F., & Gómez, P. A. (2004). Comparison of color indexes for tomato ripening. Horticultura Brasileira, 22(3), 534–537. http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0102-05362004000300006 .López-García, F., Andreu-García, A., Blasco, J., Aleixos, N., & Valiente, J. M. (2010). Automatic detection of skin defects in citrus fruits using a multivariate image analysis approach. 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Single to Double Hump Transition in the Equilibrium Distribution Function of Relativistic Particles

We unveil a transition from single peaked to bimodal velocity distribution in a relativistic fluid under increasing temperature, in contrast with a non-relativistic gas, where only a monotonic broadening of the bell-shaped distribution is observed. Such transition results from the interplay between the raise in thermal energy and the constraint of maximum velocity imposed by the speed of light. We study the Bose-Einstein, the Fermi-Dirac, and the Maxwell-J\"uttner distributions, all exhibiting the same qualitative behavior. We characterize the nature of the transition in the framework of critical phenomena and show that it is either continuous or discontinuous, depending on the group velocity. We analyze the transition in one, two, and three dimensions, with special emphasis on two-dimensions, for which a possible experiment in graphene, based on the measurement of the Johnson-Nyquist noise, is proposed.Comment: 5 pages, 5 figure

Plasmonic coupling in closed-packed ordered gallium nanoparticles

Plasmonic gallium (Ga) nanoparticles (NPs) are well known to exhibit good performance in numerous applications such as surface enhanced fluorescence and Raman spectroscopy or biosensing. However, to reach the optimal optical performance, the strength of the localized surface plasmon resonances (LSPRs) must be enhanced particularly by suitable narrowing the NP size distribution among other factors. With this purpose, our last work demonstrated the production of hexagonal ordered arrays of Ga NPs by using templates of aluminium (Al) shallow pit arrays, whose LSPRs were observed in the VIS region. The quantitative analysis of the optical properties by spectroscopic ellipsometry confirmed an outstanding improvement of the LSPR intensity and full width at half maximum (FWHM) due to the imposed ordering. Here, by engineering the template dimensions, and therefore by tuning Ga NPs size, we expand the LSPRs of the Ga NPs to cover a wider range of the electromagnetic spectrum from the UV to the IR regions. More interestingly, the factors that cause this optical performance improvement are studied with the universal plasmon ruler equation, supported with discrete dipole approximation simulations. The results allow us to conclude that the plasmonic coupling between NPs originated in the ordered systems is the main cause for the optimized optical responseThe research is supported by the MINECO (CTQ2014-53334-C2-2-R, CTQ2017-84309-C2-2-R and MAT201676824-C3-1-R) and Comunidad de Madrid (P2018/NMT4349 and S2018/NMT-4321 NANOMAGCOST) projects. ARC acknowledges Ramón y Cajal program (under contract number RYC-2015-18047

Activity/inactivity circadian rhythm shows high similarities between young obesity-induced rats and old rats

The objective of the present study was to compare differences between elderly rats and young obesity-induced rats in their activity/inactivity circadian rhythm. The investigation was motivated by the differences reported previously for the circadian rhythms of both obese and elderly humans (and other animals), and those of healthy, young or mature individuals. Three groups of rats were formed: a young control group which was fed a standard chow for rodents; a young obesity-induced group which was fed a high-fat diet for four months; and an elderly control group with rats aged 2.5 years that was fed a standard chow for rodents. Activity/inactivity data were registered through actimetry using infrared actimeter systems in each cage to detect activity. Data were logged on a computer and chronobiological analysis were performed. The results showed diurnal activity (sleep time), nocturnal activity (awake time), amplitude, acrophase, and interdaily stability to be similar between the young obesity-induced group and the elderly control group, but different in the young control group. We have concluded that obesity leads to a chronodisruption status in the body similar to the circadian rhythm degradation observed in the elderly

Use of hyperspectral transmittance imaging to evaluate the internal quality of nectarines

[EN] The internal quality of nectarines (Prunus persica L. Batsch var. nucipersica) cv. 'Big Top' (yellow flesh) and 'Magique' (white flesh) has been inspected using hyperspectral transmittance imaging. Hyperspectral images of intact fruits were acquired in the spectral range of 630-900 nm using transmittance mode during their ripening under controlled conditions. The detection of split pit disorder and classification according to an established firmness threshold were performed using PLS-DA. The prediction of the Internal Quality Index (IQI) related to ripeness was performed using PLS-R. The most important variables were selected using interval-PLS. As a result, an accuracy of 94.7% was obtained in the detection of fruits with split pit of the 'Big Top' cultivar. Accuracies of 95.7% and 94.6% were achieved in the classification of the 'Big Top' and 'Magique' cultivars, respectively, according to the firmness threshold. The internal quality was predicted through the IQI with R-2 values of 0.88 and 0.86 for the two cultivars. The results obtained indicate the great potential of hyperspectral transmittance imaging for the assessment of the internal quality of intact nectarines.This work was partially funded by INIA and FEDER funds through project RTA2015-00078-00-00. Sandra Munera thanks INIA for the FPI-INIA grant num. 43 (CPR2014-0082), partially supported by European Union FSE funds.Munera, S.; Blasco Ivars, J.; Amigo, J.; Cubero-García, S.; Talens Oliag, P.; Aleixos Borrás, MN. (2019). Use of hyperspectral transmittance imaging to evaluate the internal quality of nectarines. Biosystems Engineering. 182:54-64. https://doi.org/10.1016/j.biosystemseng.2019.04.001S546418

Stationarity, soft ergodicity, and entropy in relativistic systems

Recent molecular dynamics simulations show that a dilute relativistic gas equilibrates to a Juettner velocity distribution if ensemble velocities are measured simultaneously in the observer frame. The analysis of relativistic Brownian motion processes, on the other hand, implies that stationary one-particle distributions can differ depending on the underlying time-parameterizations. Using molecular dynamics simulations, we demonstrate how this relativistic phenomenon can be understood within a deterministic model system. We show that, depending on the time-parameterization, one can distinguish different types of soft ergodicity on the level of the one-particle distributions. Our analysis further reveals a close connection between time parameters and entropy in special relativity. A combination of different time-parameterizations can potentially be useful in simulations that combine molecular dynamics algorithms with randomized particle creation, annihilation, or decay processes.Comment: 4 page