2,302 research outputs found
Highly-efficient noise-assisted energy transport in classical oscillator systems
Photosynthesis is a biological process that involves the highly-efficient
transport of energy captured from the sun to a reaction center, where
conversion into useful biochemical energy takes place. Even though one can
always use a quantum perspective to describe any physical process, since
everything follows the laws of Quantum Mechanics, is the use of quantum theory
imperative to explain this high efficiency? Making use of the quantum-classical
correspondence of electronic energy transfer recently introduced by Eisfeld and
Briggs [Phys. Rev. E 85, 046118 (2012)], we show here that the highly-efficient
noise-assisted energy transport described by Rebentrost et al. [New J. Phys.
11, 033003 (2009)], and Plenio and Huelga [New J. Phys. 10, 113019 (2008)], as
the result of the interplay between the quantum coherent evolution of the
photosynthetic system and noise introduced by its surrounding environment, it
can be found as well in purely classical systems. The wider scope of
applicability of the enhancement of energy transfer assisted by noise might
open new ways for developing new technologies aimed at enhancing the efficiency
of a myriad of energy transfer systems, from information channels in
micro-electronic circuits to long-distance high-voltage electrical lines.Comment: 4 pages, 3 figure
EPOC en la mujer
The prevalence of chronic obstructive pulmonary disease (COPD) is increasing
worldwide, mainly due to the increase in women. In developed countries, COPD in
women is mainly a result of exposure to tobacco smoke and in developing countries
to inhalation of biomass combustion products. Underdiagnosis of COPD is more
common in women since this disease has classically been associated with men.
Moreover, COPD in women shows certain differential features, such as a greater
expression of aspects related to perception (dyspnea and health-related quality
of life), a high prevalence of malnutrition, anxiety and depression, and a
distinct distribution of emphysema from that in men. Better phenotypical
characterization of COPD in women would allow its impact on the health system to
be more accurately evaluated and more individualized therapeutic strategies to be
designe
Radiologic features of small pulmonary nodules detected in initially negative screening CT examinations: a step towards personalized screening strategies?
Results of the National Lung Screening Trial (NLST)
have invigorated the discussion around performing lung
cancer screening using low-dose computed tomography
(LDCT) of the chest. The NLST trial demonstrated a
clear benefit of LDCT screening in reducing lung cancer
and all-cause mortality, by showing reduced lung cancer
mortality in high-risk individuals by about 20%, and allcause mortality by 6.7%, compared to a control group of
subjects receiving chest radiographs
Equivalence regimes for geometric quantum discord and local quantum uncertainty
The concept of quantum discord aims at unveiling quantum correlations that go beyond those described by entanglement. Its original formulation [L. Henderson and V. Vedral, J. Phys. A: Math. Gen. 34, 6899 (2001); H. Ollivier and W. H. Zurek, Phys. Rev. Lett. 88, 017901 (2001)] is difficult to compute even for the simplest case of two-qubits systems. Alternative formulations have been developed to address this drawback, such as the geometric measure of quantum discord [L. Chang and S. Luo, Phys. Rev. A 87, 062303 (2013)] and the local quantum uncertainty [D. Girolami, T. Tufarelli, and G. Adesso, Phys. Rev. Lett. 110, 240402 (2013)] that can be evaluated in closed form for some quantum systems, such as two-qubit systems. We show here that these two measures of quantum discord are equivalent for 2×D dimensional bipartite quantum systems. By considering the relevant example of N00N states for phase estimation in lossy environments, we also show that both metrics of quantum discord quantify the decrease of quantum Fisher information of the phase estimation protocol. Given their ease of computation in 2×D bipartite systems, the geometric measure of quantum discord and the local quantum uncertainty demonstrate their relevance as computable measures of quantum discord.We acknowledge support from the Spanish Ministry of
Economy and Competitiveness (“Severo Ochoa” program
for Centres of Excellence in R&D No. SEV-2015-0522),
from Fundacio Privada Cellex, from Fundacio Mir-Puig, and
from Generalitat de Catalunya through the CERCA program.
This work was partially funded through the EMPIR
project 17FUN01-BeCOMe. The EMPIR initiative is cofunded
by the European Union Horizon 2020 Research and
Innovation Programme and the EMPIR participating states.
A.V. acknowledges financial support from PREBIST that
has received funding from the European Union Horizon
2020 Research and Innovation Programme under the Marie
Sklodowska-Curie Grant Agreement No. 754558. J.R.A. acknowledges
funding by the European Union Horizon 2020
Research and Innovation Programme (Marie Sklodowska-
Curie 765075-LIMQUET). R.J.L.M. thankfully acknowledges
financial support by CONACyT under the project
CB-2016-01/284372, and by Direcci n General de Asuntos
del Personal Acad mico, Universidad Nacional Aut noma de
M xico (DGAPA-UNAM), under the project UNAM-PAPIIT
IN102920.Peer ReviewedPostprint (author's final draft
Solid sampling determination of ZnO nanoparticles in eyeshadows by graphite furnace atomic absorption spectrometry
The application of nanoparticles (NPs) in science and technology is a fast growing field. Therefore, reliable and straightforward analytical methods are required for their fast determination in different types of samples. In this work, a method that enables the determination of the average size of ZnO NPs, besides their concentration, discriminating them from ionic zinc, has been optimized. The method is based on solid sampling high-resolution continuum source electrothermal atomic absorption spectrometry (SS-HR-CS-GFAAS), and has been applied to determination and characterization of ZnO NPs in cosmetic samples.
Recently, graphite furnace atomic absorption spectrometry has been introduced as a new tool to determine the size of nanoparticles by evaluation of the following parameters: atomization delay (tad) and atomization rate (kat). In this work both parameters (besides peak area) have been obtained from absorbance signals for a line of Zn with low sensitivity. Two multiple response surface designs have been used in order to optimize the adequate furnace program to achieve our aims. All the optimization experiments were performed using baby´s skin irritation protective cream. The optimized furnace program is shown in Table 1.
Table 1. Optimized furnace program
The size calibrations were performed against solid (powered) ZnO standards, from 50-nm to 500-nm sized nanoparticles. The correlation coefficients (R value) of the linear calibration were not worse than 0.9982. The optimized method was tested in other types of cosmetic samples such as eyeshadow samples with good results. The determination of the MNPs’ size was validated by transmission electron microscopy (TEM) and the Zn concentration in the solid samples was validated by atomic fluorescence spectroscopy (AFS).
Acknowledgements (optional) [Garamond font, 10 points]
The authors would like to thank Plan propio “Proyecto Puente” de la Universidad de Málaga for financial support of this work.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tec
Rapid magnetic microextraction to preconcentrate and determinate cadmium from environmental samples
A novel and greener ultrasonically assisted/modified cloud point extraction procedure for the preconcentration and extraction of trace cadmium from environmental samples was developed. The sorbent material was fabricated by scattering of magnetic iron nanoparticles (MNPs) over graphene oxide (GO) to obtain magnetic graphene oxide (MGO). The material was suspended in the ionic liquid 1-n-butyl-3-metilimidazolium tetrafluoroborate [BMIM][BF4]. The obtained stable colloidal suspension is named ferrofluid. GO presents excellent adsorbent properties for organic species due to the presence of the electronic π system. For this reason, the organic ligand [1,5-bis-(2-dipyridyl) methylene] thiocarbonohydrazide (DPTH) was used in order to form an organic complex of Cd. Once the DPTH ligand has been added to sample, the ferrofluid was injected and finely dispersed in the sample solution in order to extract the formed chelate as shown in Fig. 1. The complete adsorption of the quelate took place within few seconds, after that the solid was separated from the solution with the aid of a strong magnet. Cadmium ions were desorbed from the material with 1 mL of 5% acid nitric solution and quantified by electrothermal atomic absorption spectrometry (ETAAS).
The main parameters affecting the extraction and the furnace program were optimized using one-at-time method. The analytical performance under optimum conditions are the following: LOD: 0.005 µg/L, LOQ: 0.017 µg/L. Linear calibration: 0-0.25 µg/L and EF: 200. The reliability of the developed procedure was tested by relative standard deviation (% RSD), which was found to be < 5% (1.3%). The performance of the proposed procedure was checked by applying to certified reference material and spiking standard in real samplesUniversidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Different Dietary Approaches, Non-Alcoholic Fatty Liver Disease and Cardiovascular Disease: A Literature Review
Non-alcoholic fatty liver disease (NAFLD) is the first cause of chronic liver disease and is also associated with other harmful entities such as obesity, metabolic syndrome, dyslipidemia, and diabetes. NAFLD is a significant public health concern worldwide, impacting individuals of all ages, and its prevalence is projected to increase in the near future due to its connection with obesity. Intrinsic (genetics) and external (lifestyle) factors may also modulate NAFLD, and, in turn, may partly explain the observed relationship between NAFLD and cardiovascular disease (CVD). Although many drugs are been tested to treat NAFLD, to date, no drug has indication to specifically treat this disorder. Thus, the current management of NAFLD relies on lifestyle modifications and specifically on weight loss, physical activity, and the intake of a healthy diet. In the present narrative review, we will discuss the effects of certain dietary patterns on NAFLD incidence and progression
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