Characteristics and risk factors of isolated and quarantined children and adolescents during the first wave of SARS-CoV-2 pandemic: A cross-sectional study in Modena, Northern Italy

Background and aim: In early 2020, SARS-CoV-2 was declared a pandemic by the WHO and Italy was one of the first and most severely affected country in Europe. Despite the global interest about COVID-19 pandemic, several aspects of this infection are still unclear, especially in pediatric population. This study aims to investigate the characteristics of the isolated or quarantined children and adolescents followed by the Public Health Department of the Italian province of Modena during the first wave of COVID-19. Methods: The study population included all non-adult subjects aged 0-18 years who underwent isolation or quarantine during the first wave of SARS-CoV-2 pandemic from February 24 to June 18, 2020 in Modena province, Northern Italy. Results: In Modena province, 1230 children and adolescents were isolated in case of SARS-CoV-2 infection (6.3%), or quarantined due to close contact with confirmed cases (88.7%) or travelling from a high-risk area (5.0%). Among 349 individuals who underwent swab testing, 294 (84.2%) reported close contact with an infected cohabiting relative and 158 (45.3%) were symptomatic. Among all tested subjects, 78 (22.4%) resulted positive, with a higher proportion of symptomatic subjects compared with the SARS-CoV-2-negative (78.2% vs. 35.8%). Fever was mostly present in SARS-CoV-2-positive children (48.7% vs. 12.6%). Both anosmia (58.3% vs. 41.7%) and dysgeusia (54.5% vs. 45.5%) had only slightly higher frequency in SARS-CoV-2-positive. Conclusions: These findings allow to expand the knowledge regarding characteristics of non-adult subjects isolated or quarantined during the first wave of SARS-CoV-2 pandemic. (www.actabiomedica.it)

Thin metamaterial Luneburg lens for surface waves

Copyright © 2013 American Physical SocietyBy suitably patterning a metasurface, the phase velocity of surface waves may be manipulated. Here, a low-loss, thin (1/14th of the free-space wavelength), omnidirectional Luneburg lens, based upon a Sievenpiper “mushroom” array [Sievenpiper et al. IEEE Trans. Microwave Theory Tech. 47 2059 (1999)], is fabricated and characterized at microwave frequencies. Surface waves excited using a near-field point source on the perimeter of the lens, exit the opposite side of the lens as planar wave fronts. The electric field of the surface wave is mapped out experimentally and compared to numerical simulations

Diffraction-like synthetic functions to treat the scattering from large polyhedral metallic objects

This paper presents an innovative procedure that allow for the Method of Moments (MoM) analysis of electrically large objects composed of flat faces, i.e. open or closed polyhedrons with or without attached plates. The method is framed within the category of iteration-free, compressive basis function approaches. Two kinds of diffraction-like basis functions are introduced to achieve drastic memory requirement compression; relevant results compared with those obtained employing standard RWG basis functions are presented

Circadian characteristics influencing interindividual differences in tolerance and adjustment to shiftwork.

The study was carried out to evaluate whether shiftworkers showing different long-term tolerance to shiftwork differ in their circadian adjustments and/or in some behavioural characteristics. Three groups of eight workers, engaged on three shifts in a graphic plant and matched for age and work experience, were selected according to the presence or not of complaints related to shiftwork: (1) no complaints; (2) nervous complaints (anxiety/depression, severe sleep disturbances); (3) digestive disorders (gastroduodenitis, peptic ulcer). They answered questionnaires on family conditions, health status, rigidity of sleeping habits, ability to overcome drowsiness, morningness, manifest anxiety. They also recorded several physiological parameters (oral temperature, grip strength, peak expiratory flow rate, pulse rate, sleep hours) during day and night-shifts. The data obtained indicated that the characteristics of flexibility of sleeping habits, ability to overcome drowsiness, and lower manifest anxiety, are associated with better tolerance to shiftwork. These characteristics do not seem to influence the adjustment of the circadian rhythm of oral temperature passing from day to night-shifts and vice versa. Conversely, morningness appeared to be unrelated to long-term tolerance, but did influence circadian adjustments and sleep behaviour. Among the groups, the subjects with digestive disorders showed a greater phase shift and a reduction of the amplitude on night-work, suggesting a possible relationship also between the short-term circadian adjustment and the long-term tolerance to shiftwork, as pointed out by other authors

Leaky wave circularly polarized antennas based on surface impedance modulation

The concept of modulation of surface impedance is used to design very simple leaky wave lens antennas. The antennas are circularly polarized and realized on planar surfaces. Such antennas are designed by using a holographic principle and interpreting the holographic interference pattern in terms of modulation of surface impedance. The surface impedance is reconstructing by using two different approaches. In the first one, the modulation of the reactance is provided by varying the height of a grounded dielectric slab, realizing a full dielectric lens antenna. In the second one the surface impedance is synthesized by printing a dense texture of sub-wavelength metal patches on a flat grounded dielectric slab. The latter solution results in a completely flat planar antenna. Design guidelines for both lens antennas are presented and some numerical results discussed. © Copyright 2011 IEEE - All Rights Reserved

An overview of metasurfaces for thin antenna applications

In recent years, metasurfaces have become a rapidly growing domain of research in several fields of engineering and applied physics due to their ability to manipulate both phase and amplitude of electromagnetic fields. These artificial 2D-materials, usually composed of metallic elements printed on dielectric substrates, have the advantages of being low profile, lightweight as well as easy to fabricate and integrate with standard circuit technologies. In this context, this paper reviews the latest progress in metasurface antenna design, where metasurfaces are used to miniaturize the profile, increase the bandwidth, and control the radiation pattern in the near- and far-field regions

Metasurfing: Addressing Waves on Impenetrable Metasurfaces

4nonenoneMaci S.; Minatti G.; Casaletti M.; Bosiljevac M.Maci, Stefano; Minatti, Gabriele; Casaletti, Massimiliano; Bosiljevac, M

Entire-domain basis functions for scattering from large curved surfaces formulated by transformation optics

A complete set of entire-domain basis functions are introduced for the analysis of scattering from bodies with curved surfaces; they are defined via the application of a generalization of the Shannon sampling theorem. These basis functions are defined for curved patches with arbitrary contours, via a three-step procedure. First, the curved patch is mapped, via Transformation Optics, onto a flat parametric domain surrounded by a virtual anisotropic inhomogeneous space. Next, linear-phase functions are defined on the parametric flat domain; the sufficient and non-redundant number of functions is found by using a spectral domain “completeness relationship” of the delta function. Finally, the back-transformation from flat anisotropic to curved isotropic space yields the basis functions for the curved patch. The number of basis functions so obtained matches the degrees of freedom of the field known in the literature. Numerical results show the effectiveness of the representation for both fields and currents