4,522 research outputs found

    Spin-orbit mode transfer via a classical analog of quantum teleportation

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    We translate the quantum teleportation protocol into a sequence of coherent operations involving three degrees of freedom of a classical laser beam. The protocol, which we demonstrate experimentally, transfers the polarisation state of the input beam to the transverse mode of the output beam. The role of quantum entanglement is played by a non-separable mode describing the path and transverse degrees of freedom. Our protocol illustrates the possibility of new optical applications based on this intriguing classical analogue of quantum entanglement.Comment: 5 pages, 7 figure

    O látex e a borracha da mangabeira.

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    Suppression of Anderson localization of light and Brewster anomalies in disordered superlattices containing a dispersive metamaterial

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    Light propagation through 1D disordered structures composed of alternating layers, with random thicknesses, of air and a dispersive metamaterial is theoretically investigated. Both normal and oblique incidences are considered. By means of numerical simulations and an analytical theory, we have established that Anderson localization of light may be suppressed: (i) in the long wavelength limit, for a finite angle of incidence which depends on the parameters of the dispersive metamaterial; (ii) for isolated frequencies and for specific angles of incidence, corresponding to Brewster anomalies in both positive- and negative-refraction regimes of the dispersive metamaterial. These results suggest that Anderson localization of light could be explored to control and tune light propagation in disordered metamaterials.Comment: 4 two-column pages, 3 figure

    Frações húmicas e propriedade químicas e físicas de latossolos.

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    O trabalho estabeleceu correlações entre as frações orgânicas e algumas propriedades físicas e químicas de horizontes A e B de persis Latossolos, oriundas de diferentes regiões do Brasi

    Cross-amplification and characterization of microsatellite loci for the Neotropical orchid genus Epidendrum

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    In this study we tested the cross-amplification of 33 microsatellite loci previously developed for two closely related Neotropical orchid genera (Epidendrum and Laelia). A set of ten loci were polymorphic across five examined species (20 individuals each) with 2 to 15 alleles per locus. The mean expected and observed heterozygosity (average across species) ranged from 0.34 to 0.82 and from 0.27 to 0.85, respectively. In addition we tested all loci in 35 species representative of the genus Epidendrum. Of these, 26 loci showed successful amplification. Cross-application of these loci represent a potential source of co-dominant markers for evolutionary, ecological and conservation studies in this important orchid genus

    Development of hemostatic materials made of electrochemically oxidized bacterial cellulose

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    Book of Abstracts of CEB Annual Meeting 2017[Excerpt] Cellulose is the most abundant polysaccharide in nature, being the main constituent of plant cell walls. It can undergo structural modification by oxidative methods, making it absorbable when implanted in the organism, contrarily to what happens with the non-oxidized cellulose. This way it can be used as raw material in medical devices, such as absorbable hemostatic materials and as a barrier to prevent postoperative adhesions. Cellulose can also be produced by bacteria (mainly from the species Glucanocetobacter xylinus), being this way known as bacterial cellulose (BC). With the increasing use of the hemostatic materials based on oxidized cellulose in surgical procedures, there has also been an increase in the number of case studies that describe post-operative complications associated with the use of these materials. BC has improved characteristics and unique properties compared with polysaccharide derived from plants, namely a higher biocompatibility. It has therefore been the subject of increased research over the past years allowing its application in various fields, especially in biomedical applications [1]. This project aims to develop a hemostatic material to reduce post-operative complications, based on the oxidized BC, using electrochemical oxidation methods [2]. These methods are based on the stable nitroxyl radicals commercially available. [...]info:eu-repo/semantics/publishedVersio

    Biogas production from dairy cattle manure, under organic and conventional production systems.

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    The purpose of this study was to evaluate the production of biogas, as well as the biogas production potential resulting from the anaerobic biodigestion of dairy cattle manure under organic (CMOS) and conventional (CMCS) production system. Also, the concentration of thermotolerant coliforms was evaluated after the biodigestion process. Therefore, bench biodigesters prototypes were supplied with CMOS and CMCS for 30 weeks. The experimental design was completely randomized with four repetitions for each treatment. Analysis of total solids (TS), volatile solids (VS), biogas production potential, most probable number (MPN) of thermotolerant coliforms were made. The cumulative biogas production was 6.18 L and 11.15 L, when using the CMOS and CMCS, respectively. Average biogas production potential of CMCS were 0.2; 2.6 and 2.9 L kg-1 substrate, ST and SV added, respectively and for CMOS 0.1; 1.4 and 1.9 L kg-1substrate, ST and SV added, respectively. After the anaerobic biodigestion process of CMOS and CMCS, it was observed that the concentrations of thermotolerant coliforms were well below than the limit established by law

    Prediction of soil physical and chemical properties by visible and near-infrared diffuse reflectance spectroscopy in the Central Amazon.

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    Visible and near-infrared diffuse reflectance spectroscopy (VIS-NIR) has shown levels of accuracy comparable to conventional laboratory methods for estimating soil properties. Soil chemical and physical properties have been predicted by reflectance spectroscopy successfully on subtropical and temperate soils, whereas soils from tropical agro-forest regions have received less attention, especially those from tropical rainforests. A spectral characterization provides a proficient pathway for soil characterization. The first step in this process is to develop a comprehensive VIS-NIR soil library of multiple key soil properties to be used in future soil surveys. This paper presents the first VIS-NIR soil library for a remote region in the Central Amazon. We evaluated the performance of VIS-NIR for the prediction of soil properties in the Central Amazon, Brazil. Soil properties measured and predicted were: pH, Ca, Mg, Al, H, H+Al, P, organic C (SOC), sum of bases, cation exchange capacity (CEC), percentage of base saturation (V), Al saturation (m), clay, sand, silt, silt/clay (S/C), and degree of flocculation. Soil samples were scanned in the laboratory in the VIS-NIR range (350-2500 nm), and forty-one pre-processing methods were tested to improve predictions. Clay content was predicted with the highest accuracy, followed by SOC. Sand, S/C, H, Al, H+Al, CEC, m and V predictions were reasonably good. The other soil properties were poorly predicted. Among the soil properties predicted well, SOC is one of the critical soil indicators in the global carbon cycle. Besides the soil property of interest, the landscape position, soil order and depth influenced in the model performance. For silt content, pH and S/C, the model performed better in well-drained soils, whereas for SOC best predictions were obtained in poorly drained soils. The association of VIS-NIR spectral data to landforms, vegetation classes, and soil types demonstrate potential for soil characterization
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