4,488 research outputs found

    Quality of life of survivors of paediatric intensive care

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    Objective: The mortality rate in paediatric intensive care units (PICU) has fallen over the last two decades. More advanced treatment is offered to children with life-threatening disease and there is substantial interest in knowing whether long term outcome and quality of life after intensive care are acceptable

    Attenuating the crisis: the relationship between media use, prosocial political participation, and holding misinformation beliefs during the COVID-19 pandemic

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    In a global crisis like the COVID-19 pandemic, governments around the world are dependent on voluntary support of their citizens. Based on a four-wave panel survey conducted in the Netherlands between April and July 2020 (n = 1742), this study investigates the development of citizens’ engagement in prosocial political activities and what motivates such acts of political participation. With previous research indicating strong relationships between news as well as social media use and political participation, we test whether these types of information consumption drive participation over time. The spread of misinformation during the COVID-19 crisis, however, was described as an “infodemic”. The study therefore explores how holding misinformation beliefs directly and indirectly affects participation in COVID-19 related activities

    Sudden Collapse of a Granular Cluster

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    Single clusters in a vibro-fluidized granular gas in N connected compartments become unstable at strong shaking. They are experimentally shown to collapse very abruptly. The observed cluster lifetime (as a function of the driving intensity) is analytically calculated within a flux model, making use of the self-similarity of the process. After collapse, the cluster diffuses out into the uniform distribution in a self-similar way, with an anomalous diffusion exponent 1/3.Comment: 4 pages, 4 figures. Figure quality has been reduced in order to decrease file-siz

    A hybrid process combining ion exchange resin and bipolar membrane electrodialysis for reverse osmosis remineralization

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    A new reverse osmosis (RO) permeate remineralization process combining ion exchange resin and bipolar membrane electrodialysis (BMED) was developed. Its feasibility for hardness ions recovery and RO permeate remineralization was investigated. The effect of several operation conditions on the efficiency of the combined remineralization process was studied. Highly efficient cation exchange resin loading was achieved at a low flow rate and low feed solution concentration. The recovered calcium purity and yield considerably improved under gradient elution methods in comparison with commonly applied conventional isocratic elution methods using the same eluent quantity. The purity of the produced acid and base using BMED dropped noticeably with increasing feed NaCl concentration, presumably related to decreased permselectivity of the ion-exchange membranes. The drop in the purity of the calcium recovered when eluting the cation exchange resin with BMED-produced HCl in comparison with commercially available acid at 50 % yield was shown not to affect the remineralization process, where a dilution factor could be applied. This study confirmed the technical feasibility of the developed process for RO permeate remineralization. However, its application can be limited by the water source characteristics, the energy-intensive bipolar membrane process, and applied operational conditions, where more investigation is still needed.</p

    Zero-range processes with saturated condensation: the steady state and dynamics

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    We study a class of zero-range processes in which the real-space condensation phenomenon does not occur and is replaced by a saturated condensation: that is, an extensive number of finite-size "condensates" in the steady state. We determine the conditions under which this occurs, and investigate the dynamics of relaxation to the steady state. We identify two stages: a rapid initial growth of condensates followed by a slow process of activated evaporation and condensation. We analyze these nonequilibrium dynamics with a combination of meanfield approximations, first-passage time calculations and a fluctuation-dissipation type approach.Comment: 21 pages, 12 figure

    On the Microscopic Origin of Cholesteric Pitch

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    We present a microscopic analysis of the instability of the nematic phase to chirality when molecular chirality is introduced perturbatively. We show that previously neglected short-range biaxial correlations play a crucial role in determining the cholesteric pitch. We propose an order parameter which quantifies the chirality of a molecule.Comment: RevTeX 3.0, 4 pages, one included eps figure. Published versio

    The Transverse Crack Tension test revisited: An experimental and numerical study

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    Several problems arise when measuring the mode II interlaminar fracture toughness using a Transverse Crack Tension specimen; in particular, the fracture toughness depends on the geometry of the specimen and cannot be considered a material parameter. A preliminary experimental campaign was conducted on TCTs of different sizes but no fracture toughness was measured because the TCTs failed in an unacceptable way, invalidating the tests. A comprehensive numerical and experimental investigation is conducted to identify the main causes of this behaviour and a modification of the geometry of the specimen is proposed. It is believed that the obtained results represent a significant contribution in the understanding of the TCT test as a mode II characterization procedure and, at the same time, provide new guidelines to characterize the mode II crack propagation under tensile loads

    The partially asymmetric zero range process with quenched disorder

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    We consider the one-dimensional partially asymmetric zero range process where the hopping rates as well as the easy direction of hopping are random variables. For this type of disorder there is a condensation phenomena in the thermodynamic limit: the particles typically occupy one single site and the fraction of particles outside the condensate is vanishing. We use extreme value statistics and an asymptotically exact strong disorder renormalization group method to explore the properties of the steady state. In a finite system of LL sites the current vanishes as JLzJ \sim L^{-z}, where the dynamical exponent, zz, is exactly calculated. For 0<z<10<z<1 the transport is realized by NaL1zN_a \sim L^{1-z} active particles, which move with a constant velocity, whereas for z>1z>1 the transport is due to the anomalous diffusion of a single Brownian particle. Inactive particles are localized at a second special site and their number in rare realizations is macroscopic. The average density profile of inactive particles has a width of, ξδ2\xi \sim \delta^{-2}, in terms of the asymmetry parameter, δ\delta. In addition to this, we have investigated the approach to the steady state of the system through a coarsening process and found that the size of the condensate grows as nLt1/(1+z)n_L \sim t^{1/(1+z)} for large times. For the unbiased model zz is formally infinite and the coarsening is logarithmically slow.Comment: 12 pages, 9 figure
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