25,002 research outputs found

    On the influence of tyre and structural properties on the stability of bicycles

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    In recent years the Whipple Carvallo Bicycle Model has been extended to analyse high speed stability of bicycles. Various researchers have developed models taking into account the effects of front frame compliance and tyre properties, nonetheless, a systematic analysis has not been yet carried out. This paper aims at analysing parametrically the influence of front frame compliance and tyre properties on the open loop stability of bicycles. Some indexes based on the eigenvalues of the dynamic system are defined to evaluate quantitatively bicycle stability. The parametric analysis is carried out with a factorial design approach to determine the most influential parameters. A commuting and a racing bicycle are considered and numerical results show different effects of the various parameters on each bicycle. In the commuting bicycle, the tyre properties have greater influence than front frame compliance, and the weave mode has the main effect on stability. Conversely, in the racing bicycle, the front frame compliance parameters have greater influence than tyre properties, and the wobble mode has the main effect on stability

    On the Schr\"odinger equations with isotropic and anisotropic fourth-order dispersion

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    This paper deals with the Cauchy problem associated to the nonlinear fourth-order Schr\"odinger equation with isotropic and anisotropic mixed dispersion. This model is given by the equation itu+ϵΔu+δAu+λuαu=0,i\partial _{t}u+\epsilon \Delta u+\delta A u+\lambda|u|^\alpha u=0, xRn,x\in \mathbb{R}^{n}, tR,t\in \mathbb{R}, where AA represents either the operator Δ2\Delta^2 (isotropic dispersion) or i=1dxixixixi, 1d<n\sum_{i=1}^d\partial_{x_ix_ix_ix_i},\ 1\leq d<n (anisotropic dispersion), and α,ϵ,λ\alpha, \epsilon, \lambda are given real parameters. We obtain local and global well-posedness results in spaces of initial data with low regularity, such as weak-LpL^p spaces. Our analysis also includes the biharmonic and anisotropic biharmonic equation (ϵ=0)(\epsilon=0) for which, the existence of self-similar solutions is obtained as consequence of his scaling invariance. In a second part, we investigate the vanishing second order dispersion limit in the framework of weak-LpL^p spaces. We also analyze the convergence of the solutions for the nonlinear fourth-order Schr\"odinger equation itu+ϵΔu+δΔ2u+λuαu=0i\partial _{t}u+\epsilon \Delta u+\delta \Delta^2 u+\lambda|u|^\alpha u=0, as ϵ\epsilon goes to zero, in H2H^2-norm, to the solutions of the corresponding biharmonic equation itu+δΔ2u+λuαu=0i\partial _{t}u+\delta \Delta^2 u+\lambda|u|^\alpha u=0

    Optimal conclusive teleportation of quantum states

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    Quantum teleportation of qudits is revisited. In particular, we analyze the case where the quantum channel corresponds to a non-maximally entangled state and show that the success of the protocol is directly related to the problem of distinguishing non-orthogonal quantum states. The teleportation channel can be seen as a coherent superposition of two channels, one of them being a maximally entangled state thus, leading to perfect teleportation and the other, corresponding to a non-maximally entangled state living in a subspace of the d-dimensional Hilbert space. The second channel leads to a teleported state with reduced fidelity. We calculate the average fidelity of the process and show its optimality.Comment: 8 pages, revtex, no figure

    Estimate of the willing to pay for ecological panela in Colombia: Approach from the Sustainable Consumption

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    Estimation of the environmental services values, represents a crucial element in the process of taking of decisions on environmental programs and policies to develop, as well as an orientation instrument for the implementation of production patterns and more sustainable consumption. From this perspective, the present study has as purpose to estimate the willing to pay (WTP) of the consumers from Bogota of ecological panela (product obtained from sugar canne in small rural factories). For this the method of Contingent Valuation was used. By means of selected stratified sampling a sample was determined by socioeconomic stratum for the city of Bogota the consumers were asked if they would be willing to pay for ecological panela, as well as topics related with their consumption behavior, like preferences, environmental, social commitment, and their socioeconomic characteristics. By means of the combination of this method of economic valuation and qualitative information this paper concluded that the consumers are willing to pay a bigger price for these panela types, especially for the powder ecological panela. A crucial conclusion is that, the existence of a direct relationship between the socioeconomic stratum and the WTP by conventional and ecological powder panela. Finally, it was determined that the commitment for the conservation and protection of the environment, when it is perceived by the consumer like an element that it guarantees the consumption of healthy and innocuous products, it represents a decisive factor in the willing to pay a bigger price for conventional and ecological powder panela.Ecological Panela, Contingent Valuation, Sustainable Consumption, Ecological Products.

    The Continuous Challenge of Diagnosing patients with Fabry disease in Argentina : Genotype, Experiences, Anecdotes, and New Learnings

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    The lysosomal storage disorder Fabry disease (FD) is caused by pathogenic mutations in the α-galactosidase A gene, localized in X chromosome. Deficient enzymatic activity of the product of this gene, the lysosomal hydrolase α-galactosidase A, leads to accumulation of its substrate globotriaosylceramide. Diagnosis of FD starts with clinical suspicion followed by confirmatory laboratory testing. The aim of this work is to report the 14 years’ experience and learnings in the diagnosis of patients with Fabry disease in Argentina from a specialized lysosomal diseases diagnosis laboratory and to report the genotype characterization of the 25 families from Argentina with FD detected by us.Fil: Rozenfeld, Paula Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Estudios Inmunológicos y Fisiopatológicos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Estudios Inmunológicos y Fisiopatológicos; ArgentinaFil: Ceci, Romina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Estudios Inmunológicos y Fisiopatológicos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Estudios Inmunológicos y Fisiopatológicos; ArgentinaFil: Roa, Norma. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Estudios Inmunológicos y Fisiopatológicos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Instituto de Estudios Inmunológicos y Fisiopatológicos; ArgentinaFil: Kisinovsky, Isaac. Sanatorio Urquiza; Argentin
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