10,350 research outputs found

    Aharonov-Bohm oscillations in the local density of states

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    The scattering of electrons with inhomogeneities produces modulations in the local density of states of a metal. We show that electron interference contributions to these modulations are affected by the magnetic field via the Aharonov-Bohm effect. This can be exploited in a simple STM setup that serves as an Aharonov-Bohm interferometer at the nanometer scale.Comment: 4 pages, 2 figures. v2 added reference

    Quasi-normal mode analysis in BEC acoustic black holes

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    We perform a quasi-normal mode analysis of black hole configurations in Bose-Einstein condensates (BEC). In this analysis we use the full Bogoliubov dispersion relation, not just the hydrodynamic or geometric approximation. We restrict our attention to one-dimensional flows in BEC with step-like discontinuities. For this case we show that in the hydrodynamic approximation quasi-normal modes do not exist. The full dispersion relation, however, allows the existence of quasi-normal modes. Remarkably, the spectrum of these modes is not discrete but continuous.Comment: 7 pages, 3 figure

    Satisfaction and quality of life in women who undergo breast surgery: a qualitative study to develop conceptual model

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    Background: In cosmetic and reconstructive breast surgery, measurement of patient-reported outcomes has become increasingly important to research efforts and clinical care. We aimed to describe how breast conditions and breast surgery impact on patient satisfaction and quality of life. Methods: We conducted qualitative, in-depth interviews with 48 women who had undergone either breast reduction (n = 15), breast augmentation (n = 12), or breast reconstruction (n = 21) surgery in order to begin to build a theoretical understanding of patient satisfaction and quality of life in breast surgery patients. Interviews were audio-taped, transcribed verbatim and analyzed thematically. Results: The patient interviews revealed that breast conditions and breast surgery impact women in the following six main areas: satisfaction with breasts; satisfaction with overall outcome; psychosocial well-being; sexual well-being; physical well-being; and satisfaction with the process of care. We used these six themes to form the basis of a conceptual framework of patient satisfaction and quality of life in women who undergo breast surgery. Conclusion: Our conceptual framework establishes the main issues of concern for breast surgery patients. This new framework can be used to help develop local guidelines for future clinical assessment, management and measurement, establish the validity of the current management strategies, and develop evidence-based guidance for the development of new patient reported outcome measures for future outcomes research

    An overview on complex Kleinian groups

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    Classical Kleinian groups are discrete subgroups of PSL(2,\C) acting on the complex projective line 1\P^1, which actually coincides with the Riemann sphere, with non-empty region of discontinuity. These can also be regarded as the monodromy groups of certain differential equations. These groups have played a major role in many aspects of mathematics for decades, and also in physics. It is thus natural to study discrete subgroups of the projective group PSL(n,\C), n>2 n > 2. Surprisingly, this is a branch of mathematics which is in its childhood, and in this article we give an overview of it

    Quantum critical behavior of electrons at the edge of charge order

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    We consider quantum critical points (QCP) in which quantum fluctuations associated with charge rather than magnetic order induce unconventional metallic properties. Based on finite-T calculations on a two-dimensional extended Hubbard model we show how the coherence scale T* characteristic of Fermi liquid behavior of the homogeneous metal vanishes at the onset of charge order. A strong effective mass enhancement reminiscent of heavy fermion behavior indicates the possible destruction of quasiparticles at the QCP. Experimental probes on quarter-filled layered organic materials are proposed for unveiling the behavior of electrons across the quantum critical region.Comment: 4 pages, 4 figures, accepted for publication in Phys. Rev. Let

    Una nueva asociación de matorral gipsófilo para el Sur de España (Provincia Bética)

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    El estudio de los matorrales gípsicos en el sur de España, revela la presencia de una comunidad diferente del resto de asociaciones descritas hasta el momento dentro de la alianza Lepidion subulati, al existir diferencias florísticas, ecológicas y biogeográficas. Por ello se propone la asociación Ononido angustifolii-Anthyllidetum cytisoidi nova, con un área subbética e hispalense, que se presenta en ambientes, secos y subhúmedos, sobre substratos gípsicos, los cuales dependiendo del ombrotipo se encuentran más o menos lavados, por lo que el matorral puede presentar más o menos gipsófitos estrictos. Asociación que se desarrolla sobre sustratos gípsicos, los cuales experimentan una pérdida de sales en ambientes seco-subhúmedos, por lo que esta nueva comunidad presenta un bajo porcentaje de gipsófilos estrictos frente a una mayor frecuencia de especies menos estrictas. Por lo que se propone la nueva alianza Resedo constrictae-Helianthemion syriacae nova de distribución ibérico-magrebíA study of the thickets growing on gypsum soils in the south of Spain reveals the presence of a community different from the other associations already described within the suballiance Lepidienion subulati as a result of the floristic, ecological and biogeographical differences. Therefore, we propose the association Ononido angustifolii-Anthyllidetum cytisoidi nova with a Subbetic and Hispalensean distribution. The association occurs in semiarid, dry and subhumid environments, on gypsum soils which, depending on the ombrotype, are more or less washed-out and, consequently, the thicket may comprise more o less strict gypsophytes. The association grows on gypsum soils which undergo salt deprivation in dry-subhumid environments. Thus, in this new community the percentage of strict gypsophilous taxa is low as compared to the number of less strict gypsophytes. To propose the new alliance Resedo constrictae-Helianthemion syriacae iberico-magrebi distribution

    Optimization of lighting projects including photopic and circadian criteria: A simplified action protocol

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    Lighting projects that consider parameters related to circadian light remain rare. Using controlled lighting on both photopic and melanopic levels, this study aims to simplify the design of circadian lighting projects based on traditional photometric parameters and calculations. A real classroom is used to illustrate the behavior of horizontal (visual stimuli) and vertical (circadian contribution) illuminances under different design parameters, such as the varied reflectance of walls, ceiling, and floor; varied spatial distribution curves, including the number and position of luminaires; and across the spectral power distribution of a variety of LEDs. In this work, we seek to clarify and simplify to the greatest possible extent the meaning and scope of various lighting standards while establishing simple protocols. Our results will enable designers to carry out optimized lighting projects from both the photometric and circadian perspectives

    Bioclimatology, structure, and conservation perspectives of Quercus pyrenaica, Acer opalus subsp. Granatensis, and Corylus avellana deciduous forests on Mediterranean bioclimate in the South-Central part of the Iberian Peninsula

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    The plant variability in the southern Iberian Peninsula consists of around 3500 different taxa due to its high bioclimatic, geographic, and geological diversity. The deciduous forests in the southern Iberian Peninsula are located in regions with topographies and specific bioclimatic conditions that allow for the survival of taxa that are typical of cooler and wetter bioclimatic regions and therefore represent the relict evidence of colder and more humid paleoclimatic conditions. The floristic composition of 421 samples of deciduous forests in the south-central part of the Iberian Peninsula were analyzed. The ecological importance index (IVI) was calculated, where the most important tree species were Quercuspyrenaica, Aceropalus subsp. Granatensis, and Corylusavellana. These species are uncommon in the south-central part of the Iberian Peninsula, forming forests of little extension. An analysis of the vertical distribution of the species (stratum) shows that the majority of the species of stratum 3 (hemicriptophics, camephytes, geophites, and nanophanerophytes) are characteristic of deciduous forests, and their presence is positively correlated with high values of bioclimatic variables related to humidity and presence of water in the soil (nemoral environments), while they are negatively correlated with high values of bioclimatic variables related to high temperatures, evapotranspiration, and aridity. This work demonstrates that several characteristic deciduous forest taxa are more vulnerable to disappearance due to the loss of their nemoral conditions caused by gaps in the tree or shrub canopy. These gaps lead to an increase in evapotranspiration, excess insolation, and a consequent loss of water and humidity in the microclimatic conditions.info:eu-repo/semantics/publishedVersio
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