6,110 research outputs found

    Information theory of quantum systems with some hydrogenic applications

    Full text link
    The information-theoretic representation of quantum systems, which complements the familiar energy description of the density-functional and wave-function-based theories, is here discussed. According to it, the internal disorder of the quantum-mechanical non-relativistic systems can be quantified by various single (Fisher information, Shannon entropy) and composite (e.g. Cramer-Rao, LMC shape and Fisher-Shannon complexity) functionals of the Schr\"odinger probability density. First, we examine these concepts and its application to quantum systems with central potentials. Then, we calculate these measures for hydrogenic systems, emphasizing their predictive power for various physical phenomena. Finally, some recent open problems are pointed out.Comment: 9 pages, 3 figure

    Full two-photon downconversion of just a single photon

    Get PDF
    We demonstrate, both numerically and analytically, that it is possible to generate two photons from one and only one photon. We characterize the output two photon field and make our calculations close to reality by including losses. Our proposal relies on real or artificial three-level atoms with a cyclic transition strongly coupled to a one-dimensional waveguide. We show that close to perfect downconversion with efficiency over 99% is reachable using state-of-the-art Waveguide QED architectures such as photonic crystals or superconducting circuits. In particular, we sketch an implementation in circuit QED, where the three level atom is a transmon

    Betalains and phenolic compounds of leaves and stems of Alternanthera brasiliana and Alternanthera tenella

    Get PDF
    Betacyanins and phenolic compounds from acetonitrile:acidified water extracts of Alternanthera brasiliana and Alternanthera tenella were characterized and quantified using a high-performance liquid chromatography system coupled with diode array and electrospray mass spectrometry detection. Four betacyanins (amaranthine, isoamaranthine, betanin and isobetanin) were tentatively identified and quantified. Twenty eight phenolic compounds of four different families (hydroxybenzoic and hydroxycinnamic acids, flavones and flavonols) were separated and characterized on the basis of their accurate MS and MS/MS information out of which ten compounds were confirmed by authentic standards. These plant species could be considered as an especially rich source of natural bioactive compounds and potential food colorants. A. brasiliana showed the highest betacyanin and polyphenols content (89 μg/g and 35,243 μg/g, respectively). Among polyphenols, flavonols were the more abundant (kaempferol-glucoside, kaempferol-rutinoside and kaempferol-rhamnosyl-rhamnosyl-glycoside). Meanwhile, A. tenella showed a different polyphenols profile with flavones as major compounds (glucopyranosil-vitexin and vitexin). As a novelty, pentosyl-vitexin and pentosyl-isovitexin were detected for the first time in Alternanthera plants. Both A. brasiliana and A. tenella leaves showed high total polyphenol content and in vitro antioxidant activity (FRAP). These results provide an analytical base concerning the phenolic and betalains composition and the antioxidant properties of two members of the promising Alternanthera gender, for subsequent applications, such as functional food ingredients.Fil: Deladino, Lorena. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Alvarez, I.. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia y Tecnologia de Alimentos y Nutrición; EspañaFil: De Ancos, B.. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia y Tecnologia de Alimentos y Nutrición; EspañaFil: Sánchez Moreno, C.. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia y Tecnologia de Alimentos y Nutrición; EspañaFil: Molina García, A. D.. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia y Tecnologia de Alimentos y Nutrición; EspañaFil: Schneider Teixeira, Aline. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; Argentina. Consejo Superior de Investigaciones Científicas. Instituto de Ciencia y Tecnologia de Alimentos y Nutrición; Españ

    Electron microscopy study of CeOx–Pd/α-Al2O3 catalysts for methane dry reforming

    Get PDF
    We have investigated the interaction between Pd and Ce in a 0.47 wt % CeOx–Pd 1 wt %/ -Al2O3 catalyst that is used in the reforming reaction of CH4 with CO2. The freshly reduced catalyst was characterized by various electron microscopy techniques, such as elemental mapping, Z-contrast imaging, and electron energy-loss spectroscopy to understand the role of Ce on a microscopic scale. The high spatial resolution elemental mapping indicates that CeOx is located in close proximity of the palladium nanoparticles. High-resolution lattice images and energy-loss spectra obtained in the vicinity of the Pd particles show an anisotropic distribution of CeOx crystallites limited to the interface region between Pd and the substrate but not covering the surface of the Pd nanoparticles. Energy-loss near edge fine structure of Pd M edges reveals that the Pd nanoparticles are not oxidized.Fil: Moreno, M. S.. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; ArgentinaFil: Wang, Feiya. National Institute for Nanotechnology; CanadáFil: Malac, M.. National Institute for Nanotechnology; CanadáFil: Kasama, T.. University of Cambridge; Reino UnidoFil: Gigola, Carlos Eugenio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Costilla, Ignacio Oscar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Planta Piloto de Ingeniería Química. Universidad Nacional del Sur. Planta Piloto de Ingeniería Química; ArgentinaFil: Sánchez, M. D.. Universidad Nacional del Sur. Departamento de Física; Argentin

    Real time leak detection and isolation in pipelines: a comparison between Sliding Mode Observer and algebraic steady state method

    Get PDF
    The purpose of this paper is to compare two different algorithms used to detect and isolate water leaks in a pipeline. One method is based on a Sliding Mode Observer and the second method is an Algebraic method obtained from the pipeline model in steady state. Because of the simplicity of both methods, they can be easily implemented. The methods were tested offline with real time data and the Algebraic method was also implemented online. Satisfactory results are shown through some experiments.Consejo Nacional de Ciencia y Tecnologí

    Do envy and compassion pave the way to unhappiness? Social preferences and life satisfaction in a Spanish city

    Get PDF
    Mounting evidence shows that people’s self-reported life satisfaction (LS) is negatively related to income inequality. Under the interpretation that the relationship between macro-level variables and LS reflects individuals’ social preferences, this finding indicates that most people display inequality-averse preferences. We explore the relationship between self-reports on inequality aversion and LS in a citywide representative survey/experiment conducted in Spain. If self-reported well-being can be used to infer people’s social preferences, LS should correlate negatively with both “envy” and “compassion” scores (i.e., how much one suffers from disadvantageous and advantageous inequality, respectively). We find that LS relates negatively to envy but positively to compassion, which would imply that suffering from observing poorer others, paradoxically, increases well-being. Using an incentivized Dictator Game as a measure of generous behavior, we reject the hypothesis that the positive link between compassion and LS is actually driven by generosity. We discuss how these findings could indicate that the way LS is used to assess social preferences in the population should be revised

    Caveolin-1 Modulates Mechanotransduction Responses to Substrate Stiffness through Actin-Dependent Control of YAP

    Get PDF
    The transcriptional regulator YAP orchestrates many cellular functions, including tissue homeostasis, organ growth control, and tumorigenesis. Mechanical stimuli are a key input to YAP activity, but the mechanisms controlling this regulation remain largely uncharacterized. We show that CAV1 positively modulates the YAP mechanoresponse to substrate stiffness through actin-cytoskeleton-dependent and Hippo-kinase-independent mechanisms. RHO activity is necessary, but not sufficient, for CAV1-dependent mechanoregulation of YAP activity. Systematic quantitative interactomic studies and image-based small interfering RNA (siRNA) screens provide evidence that this actin-dependent regulation is determined by YAP interaction with the 14-3-3 protein YWHAH. Constitutive YAP activation rescued phenotypes associated with CAV1 loss, including defective extracellular matrix (ECM) remodeling. CAV1-mediated control of YAP activity was validated in vivo in a model of pancreatitis-driven acinar-to-ductal metaplasia. We propose that this CAV1-YAP mechanotransduction system controls a significant share of cell programs linked to these two pivotal regulators, with potentially broad physiological and pathological implications. Moreno-Vicente et al. report that CAV1, a key component of PM mechanosensing caveolae, mediates adaptation to ECM rigidity by modulating YAP activity through the control of actin dynamics and phosphorylation-dependent interaction of YAP with the 14-3-3-domain protein YWHAH. Cav1-dependent YAP regulation drives two pathophysiological processes: ECM remodeling and pancreatic ADM. © 2018 The Author

    Changes in epilithic diatom assemblages in a Mediterranean high mountain lake (Laguna de La Caldera, Sierra Nevada, Spain) after a period of drought

    Get PDF
    The epilithic diatom assemblages studied in the high mountain lake “La Caldera” (Granada, Spain) from 1996 to 1998 went through two clearly different stages. The initial one, in 1996, corresponded to the reflooding of the basin after a severe drought and was composed mainly of the colonising species Fragilaria rumpens, together with a lesser presence of Nitzschia sublinearis and Hantzschia amphioxys. The predominant presence of F. rumpens at the end of the summer of 2006 coincided with low species diversity (values of Shannon and Wiener Index: 0.3-0.6). During the following two years another assemblage established itself, dominated by Achnanthidium minutissimum, which is considered to be more stable and widespread among the lakes of the Sierra Nevada. The most notable subdominant species (less than 20% of relative abundance) in this assemblage were: Encyonema minutum, Encyonopsis microcephala and Navicula cryptocephala. The diversity values during this second period were much higher than in the first: 1.0-2.2. Nutrient concentrations were measured separately in the limnetic (epilimnetic) and benthic (epilithic) environments. These abiotic parameters show that the dynamics of ammonia and silica were much the same in both, showing a gradual decrease from the beginning to the end of the study period. Epilimnetic phosphorus followed a similar pattern to ammonia and silica. In the epilithon, nitrates and phosphates increased during the first year, only to descend notably during the second. The effect of other environmental parameters such as temperature and the preceding drought on the dynamics of the diatom assemblage are discussed. Ratio DIN:SRP let us test the different degrees of phosphorus limitation in epilithon and epilimnion environments; our results suggest that phosphorus limitation of primary production in high mountain lakes is much more severe in the limnetic environment that it is in the epilithon.Chemical analyses were funded by the European project Mountain Lake Research (MOLAR)
    corecore