2,096 research outputs found

    Numerical study of two-dimensional moist symmetric instability

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    The 2-D version of the non-hydrostatic fully compressible model MOLOCH developed at ISAC-CNR was used in idealized set-up to study the start-up and finite amplitude evolution of symmetric instability. The unstable basic state was designed by numerical integration of the equation which defines saturated equivalent potential vorticity q<sub>e</sub><sup>*</sup>. We present the structure and growth rates of the linear modes both for a supersaturated initial state ("super"-linear mode) and for a saturated one ("pseudo"-linear mode) and the modifications induced on the base state by their finite amplitude evolution

    Numerical study of a banded precipitation event over Italy

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    Satellite images of 30 October 2008 show the development over north-central Italy of rainbands and multiple waves during a strong south-westerly wind episode associated with a deepening synoptic trough and cold front passage. The event was studied by means of the ISAC model chain constituted of the hydrostatic model BOLAM and the nested non-hydrostatic model MOLOCH at 1.1 km resolution. Diagnostics of model output was performed to reveal the physical origin of the dynamical features and precipitation field as simulated. Based on our results we propose a theoretical framework in which symmetric instability underlies some of the observed precipitation patterns

    Numerical study of a banded precipitation event over Italy

    Get PDF
    Satellite images of 30 October 2008 show the development over north-central Italy of rainbands and multiple waves during a strong south-westerly wind episode associated with a deepening synoptic trough and cold front passage. The event was studied by means of the ISAC model chain constituted of the hydrostatic model BOLAM and the nested non-hydrostatic model MOLOCH at 1.1 km resolution. Diagnostics of model output was performed to reveal the physical origin of the dynamical features and precipitation field as simulated. Based on our results we propose a theoretical framework in which symmetric instability underlies some of the observed precipitation patterns

    A Method for Generating a Well-Distributed Pareto Set in Nonlinear Multiobjective Optimization

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    A method is presented for generating a well-distributed Pareto set in nonlinear multiobjective optimization. The approach shares conceptual similarity with the Physical Programming-based method, the Normal-Boundary Intersection and the Normal Constraint methods, in its systematic approach investigating the objective space in order to obtain a well-distributed Pareto set. The proposed approach is based on the generalization of the class functions which allows the orientation of the search domain to be conducted in the objective space. It is shown that the proposed modification allows the method to generate an even representation of the entire Pareto surface. The generation is performed for both convex and nonconvex Pareto frontiers. A simple algorithm has been proposed to remove local Pareto solutions. The suggested approach has been verified by several test cases, including the generation of both convex and concave Pareto frontiers

    Case Report: Coexistence of SUNCT and Hypnic Headache in the Same Patient

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    Background: Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) and hypnic headache (HH) are two exceedingly rare and distinctly classified primary headaches. The hypothalamus seems to be a crucial region involved in the pathophysiology of both conditions, but no cases of SUNCT and HH co-occurrence have been described so far. Case results: A 49-year-old woman who has been suffering from SUNCT for years, with alternation of symptomatic periods and remissions, developed a new headache with different clinical features, presenting exclusively during sleep and with a dramatic responsiveness to caffeine, that met the diagnostic criteria for HH. Conclusions: The available literature suggests that SUNCT and HH are different conditions but the association in the same patient that we describe supports the concept that they are not mutually exclusive. Further studies are needed to establish if they share a common pathophysiological mechanism

    SARS-CoV-2/COVID-19 vaccines: The promises and the challenges ahead

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    : The development of a new vaccine usually consists of a linear sequence of several steps and lasts many years [...]

    Raman excitation spectroscopy of carbon nanotubes: effects of pressure medium and pressure

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    Raman excitation and emission spectra for the radial breathing mode (RBM) are reported, together with a preliminary analysis. From the position of the peaks on the two-dimensional plot of excitation resonance energy against Raman shift, the chiral indices (m, n) for each peak are identified. Peaks shift from their positions in air when different pressure media are added - water, hexane, sulphuric acid - and when the nanotubes are unbundled in water with surfactant and sonication. The shift is about 2 - 3 cm-1 in RBM frequency, but unexpectedly large in resonance energy, being spread over up to 100meV for a given peak. This contrasts with the effect of pressure. The shift of the peaks of semiconducting nanotubes in water under pressure is orthogonal to the shift from air to water. This permits the separation of the effects of the pressure medium and the pressure, and will enable the true pressure coefficients of the RBM and the other Raman peaks for each (m, n) to be established unambiguously.Comment: 6 pages, 3 Figures, Proceedings of EHPRG 2011 (Paris

    Are psychological status and trust in information related to vaccine hesitancy during COVID-19 pandemic? A latent class and mediation analyses in Italy

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    Despite the recognized benefits of the COVID-19 vaccination, vaccine hesitancy (VH) remains one of the biggest challenges of the mass vaccination campaign. Most studies investigating VH determinants focused on socio-demographics and direct relationships. In this study, we aimed at: 1) identifying subgroups of people differently affected by the pandemic, in terms of psychological status; 2) investigating the role of psychological status and trust in information as possible mediators of the relationship between individual characteristics and VH. To this purpose, a latent class analysis (LCA) followed by a mediation analysis were carried out on data from a survey conducted in January 2021 on 1011 Italian citizens. LCA identified four different subgroups characterized by a differential psychological impact of the pandemic: the extremely affected (21.1%), the highly affected (49.1%), the moderately affected (21.8%) and the slightly affected (8%). We found that VH decreased with the increase of psychological impact (from 59.3% to 23.9%). In the mediation analysis, past vaccination refusal, age 45-54 years and lower-than-average income, were all indirectly related to higher VH through mistrust in COVID-19 information. Differently, the psychological impact counteracted the greater VH in females, the negative effect of social media among youngest (<35 years) and the negative effect of mistrust in the lower-than-average-income subgroup. Knowledge of psychological profile of hesitant individuals, their level of trust and the sources of information they access, together with their sociodemographic characteristics provides a more comprehensive picture of VH determinants that can be used by public health stakeholders to effectively design and adapt communication campaigns
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