Diluted planar ferromagnets: nonlinear excitations on a non-simply connected manifold

We study the behavior of magnetic vortices on a two-dimensional support manifold being not simply connected. It is done by considering the continuum approach of the XY-model on a plane with two disks removed from it. We argue that an effective attractive interaction between the two disks may exist due to the presence of a vortex. The results can be applied to diluted planar ferromagnets with easy-plane anisotropy, where the disks can be seen as nonmagnetic impurities. Simulations are also used to test the predictions of the continuum limit.Comment: 5 pages, 6 figure

Evaluación de las propiedades físico-mecánicas de morteros de albañilería producidos en base de cemento y cal con áridos reciclados mixtos

This study investigated the physical-mechanical effects of cement-lime mortars containing recycled aggregate of construction and demolition waste (CDW). The natural aggregate (NA) was replaced by volume at 25%, 50%, 75% and 100% by mixed recycled aggregate (MRA) obtained from the CDW crushing. Five types of mortars were prepared with a volumetric ratio of 1:1:6 (cement, lime and aggregate) and water/binder ratio based on the fixed consistency of 260 mm. The effects of MRA on fresh and hardened mortars’ properties were analyzed. The results were analyzed using a one-way ANOVA. MRA incorporation improved most of the physical-mechanical properties of mortars tested, except for hardened bulk density, water absorption and porosity. In the long-run, mechanical strengths significantly increased in all compositions, especially those with higher percentages of MRA. The results obtained showed that the use of MRA in masonry mortars is an alternative to reduce the generation of waste and consumption of natural resources.Este estudio investigó los efectos físico-mecánicos de los morteros de cemento y cal con áridos reciclados de residuos de construcción y demolición (RCD). El árido natural (AN) se reemplazó en volumen al 25%, 50%, 75% y 100% por el árido reciclado mixto (ARM) obtenido de la trituración de RCD. Se prepararon cinco tipos de morteros con una relación volumétrica de 1: 1: 6 (cemento, cal y áridos) y una relación de agua / aglomerante en función de la consistencia fija de 260 mm. Se analizaron los efectos del ARM en las propiedades de los morteros frescos y endurecidos. Los resultados se analizaron utilizando un ANOVA-simple. La incorporación de ARM mejoró la mayoría de las propiedades físico-mecánicas de los morteros, excepto la densidad aparente endurecida, la absorción de agua y la porosidad. A largo plazo, las resistencias mecánicas aumentaron significativamente en todas las composiciones, especialmente en aquellas con porcentajes más altos de ARM. Los resultados obtenidos mostraron que el uso de ARM en morteros de albañilería es una alternativa para reducir la generación de residuos y el consumo de recursos naturales

Solution and Asymptotic Behavior for a Nonlocal Coupled System of Reaction-Diffusion

This paper concerns with existence, uniqueness and asymptotic behavior of the solutions for a nonlocal coupled system of reaction-diffusion. We prove the existence and uniqueness of weak solutions by the Faedo-Galerkin method and exponential decay of solutions by the classic energy method. We improve the results obtained by Chipot-Lovato and Menezes for coupled systems. A numerical scheme is presented

Development and method validation for determination of 128 pesticides in bananas by modified QuEChERS and UHPLC–MS/MS analysis

AbstractA multiresidue method for the quantification of 128 pesticides in banana is described. It involves the application of a modified QuEChERS procedure followed by UHPLC–MS/MS (Ultra High Performance Liquid Chromatography coupled to Tandem Mass Spectrometry) analysis. The method was validated according to the European Union SANCO/12495/2011 guidelines and Brazilian Manual of Analytical Quality Assurance. The validation levels were 10.0; 25.0; 50.0 and 100 μg kg−1. Acceptable values were obtained for the following parameters: linearity, limit of detection – LOD (5.00 μg kg−1) and limit of quantification – LOQ (10.0 μg kg−1), except for fenamiphos and mevinphos (LOD = 7.5 μg kg−1 and LOQ = 25 μg kg−1), trueness (for the levels: 10.0, 25.0, 50.0 and 100 μg kg−1 the recovery assays values were between 70 and 120%) except for methamidophos at 10 μg kg−1 level (67.5%), intermediate precision (<20.0%) and measurement uncertainty tests (<50.0%). These results demonstrate the applicability of this method in the routine practice by the laboratories of Ministry of Agriculture, Livestock and Food Supply of Brazil that attend the National Control Plan for Residues and Contaminants (PNCRC)

Thermodynamic Properties of the One-Dimensional Extended Quantum Compass Model in the Presence of a Transverse Field

The presence of a quantum critical point can significantly affect the thermodynamic properties of a material at finite temperatures. This is reflected, e.g., in the entropy landscape S(T; c) in the vicinity of a quantum critical point, yielding particularly strong variations for varying the tuning parameter c such as magnetic field. In this work we have studied the thermodynamic properties of the quantum compass model in the presence of a transverse field. The specific heat, entropy and cooling rate under an adiabatic demagnetization process have been calculated. During an adiabatic (de)magnetization process temperature drops in the vicinity of a field-induced zero-temperature quantum phase transitions. However close to field-induced quantum phase transitions we observe a large magnetocaloric effect

High-Speed Cylindrical Collapse of Two Perfect Fluids

In this paper, the study of the gravitational collapse of cylindrically distributed two perfect fluid system has been carried out. It is assumed that the collapsing speeds of the two fluids are very large. We explore this condition by using the high-speed approximation scheme. There arise two cases, i.e., bounded and vanishing of the ratios of the pressures with densities of two fluids given by $c_s, d_s$. It is shown that the high-speed approximation scheme breaks down by non-zero pressures $p_1, p_2$ when $c_s, d_s$ are bounded below by some positive constants. The failure of the high-speed approximation scheme at some particular time of the gravitational collapse suggests the uncertainity on the evolution at and after this time. In the bounded case, the naked singularity formation seems to be impossible for the cylindrical two perfect fluids. For the vanishing case, if a linear equation of state is used, the high-speed collapse does not break down by the effects of the pressures and consequently a naked singularity forms. This work provides the generalisation of the results already given by Nakao and Morisawa [1] for the perfect fluid.Comment: 11 pages, 1 figure, accepted for publication in Gen. Rel. Gra

Continuous variable entanglement and quantum state teleportation between optical and macroscopic vibrational modes through radiation pressure

We study an isolated, perfectly reflecting, mirror illuminated by an intense laser pulse. We show that the resulting radiation pressure efficiently entangles a mirror vibrational mode with the two reflected optical sideband modes of the incident carrier beam. The entanglement of the resulting three-mode state is studied in detail and it is shown to be robust against the mirror mode temperature. We then show how this continuous variable entanglement can be profitably used to teleport an unknown quantum state of an optical mode onto the vibrational mode of the mirror.Comment: 18 pages, 10 figure

ACANTHOSTOMUM GNERII SZIDAT, 1954 (DIGENEA: CRYPTOGONIMIDAE) DE RHAMDIA QUELEN (QUOY & GAIMARD, 1824)

Acanthostomum gnerii és un digenea frecuentemente reportado en el intestino de Siluriformes y bien distribuida en el centro y suramérica. El objetivo de este estudio es proporcionar información adicional sobre las características morfológicas de la A. gnerii por secciones histológicas y microscopio electrónico de barrido, así como para proporcionar mediciones comparativas de Acanthostomum spp.. Diferente de registros anteriores de este helminto en Rhamdia sp., los espécimes de presente estudio presentearon dos brazos en la porción anterior del cuerpo luego después de la faringe. Ellos se juntan en un poro lateral en el lado esquierdo del cuerpo semelhante al observado en A. proctophorum y A. minimum. Esta morfología no hay sido descripta como característica válida para Acanthostomidae. La variación morfológica podria estar asociada a diferentes poblaciones de la misma especie. Nuevos estudios usando tecnicas moleculares son recomendados para certificar se esta característica coresponde a la diversidad de A. gnerii encuentrada en otras especies de peces

Quantification of structure–property relationships for plant polyesters reveals suberin and cutin idiosyncrasies

Polyesters, as they exist in planta, are promising materials with which to begin the development of “green” replacements. Cutin and suberin, polyesters found ubiquitously in plants, are prime candidates. Samples enriched for plant polyesters, and in which their native backbones were largely preserved, were studied to identify “natural” structural features; features that influence critical physical properties. Quantitative nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), and X-ray scattering methods were used to quantify structure–property relationships in these polymeric materials. The degree of esterification, namely, the presence of acylglycerol linkages in suberin and of secondary esters in cutin, and the existence of mid-chain epoxide groups defining the packing of the aliphatic chains were observed. This packing determines polymer crystallinity, the resulting crystal structure, and the melting temperature. To evaluate the strength of this rule, tomato cutin from the same genotype, studying wild-type plants and two well-characterized mutants, was analyzed. The results show that cutin’s material properties are influenced by the amount of unbound aliphatic hydroxyl groups and by the length of the aliphatic chain. Collectively, the acquired data can be used as a tool to guide the selection of plant polyesters with precise structural features, and hence physicochemical properties