A novel methodology for epidemic risk assessment of COVID-19 outbreak.

We propose a novel data-driven framework for assessing the a-priori epidemic risk of a geographical area and for identifying high-risk areas within a country. Our risk index is evaluated as a function of three different components: the hazard of the disease, the exposure of the area and the vulnerability of its inhabitants. As an application, we discuss the case of COVID-19 outbreak in Italy. We characterize each of the twenty Italian regions by using available historical data on air pollution, human mobility, winter temperature, housing concentration, health care density, population size and age. We find that the epidemic risk is higher in some of the Northern regions with respect to Central and Southern Italy. The corresponding risk index shows correlations with the available official data on the number of infected individuals, patients in intensive care and deceased patients, and can help explaining why regions such as Lombardia, Emilia-Romagna, Piemonte and Veneto have suffered much more than the rest of the country. Although the COVID-19 outbreak started in both North (Lombardia) and Central Italy (Lazio) almost at the same time, when the first cases were officially certified at the beginning of 2020, the disease has spread faster and with heavier consequences in regions with higher epidemic risk. Our framework can be extended and tested on other epidemic data, such as those on seasonal flu, and applied to other countries. We also present a policy model connected with our methodology, which might help policy-makers to take informed decisions.

Detecting complex network modularity by dynamical clustering.

Based on cluster desynchronization properties of phase oscillators, we introduce an efficient method for the detection and identification of modules in complex networks. The performance of the algorithm is tested on computer generated and real-world networks whose modular structure is already known or has been studied by means of other methods. The algorithm attains a high level of precision, especially when the modular units are very mixed and hardly detectable by the other methods, with a computational effort O(KN) on a generic graph with N nodes and K links.

Analysis of self-organized criticality in the Olami-Feder-Christensen model and in real earthquakes.

We perform an analysis on the dissipative Olami-Feder-Christensen model on a small world topology considering avalanche size differences. We show that when criticality appears, the probability density functions (PDFs) for the avalanche size differences at different times have fat tails with a q-Gaussian shape. This behavior does not depend on the time interval adopted and is found also when considering energy differences between real earthquakes. Such a result can be analytically understood if the sizes (released energies) of the avalanches (earthquakes) have no correlations. Our findings support the hypothesis that a self-organized criticality mechanism with long-range interactions is at the origin of seismic events and indicate that it is not possible to predict the magnitude of the next earthquake knowing those of the previous ones.

[5 years of activity in a small coronary unit. Experiences and considerations]. / 5 anni di attività in una piccola unità coronarica. Esperienze e considerazioni.

Five years' experience at the coronary unit of the S. Angelo Hospital medical division is described. Practical considerations are offered with regard to the management of arrhythmia with drugs, electroconversion and electrostimulation.

Photophoretic force on particles for low Knudsen number.

Calculations are presented for the photophoretic force on a spherical aerosol particle with size much larger than the mean free path of the surrounding gas molecules. Very good agreement is shown with recent experimental data. The results show that both components of the complex refractive index can be inferred from radiometric measurements.

Surface waves and the radiative properties of micron-sized particles.

The internal and external field solutions for a composite particle are used to show the importance of the few angstroms closest to the surface in determining the radiative properties of micron-sized particulates. The physical mechanism responsible for the enhanced emissivity and the connection with surface waves are presented.

Comprehensive model of the photophoretic force on a spherical microparticle.

The photophoretic force is described by a comprehensive model containing aspects of both the optical local-field and gas-dynamic properties. It is shown that the model is in good agreement with detailed experimental data and provides a new means for measuring optical constants of microparticles.

Molecular spectroscopy of a single aerosol particle.

The absorption spectrum of a single micrometer-sized aerosol particle is measured for the first reported time in the IR. Particle absorption is determined through the IR modulation of visible scattered light near a structure resonance. This technique, termed structure resonance modulation spectroscopy, is used to measure the IR absorption spectrum of an (NH(4))(2)SO(4) aerosol droplet of 5.4-microm diameter in the region from 970 to 1280 cm(-1). The resulting spectrum, when fitted by Mie theory, enables one to determine the molecular composition of the droplet.

Far-infrared high-resolution Fourier transform spectrometer: applications to H(2)O, NH(3), and NO(2) lines.

A Michelson-type Fourier transform spectrometer has been constructed for high resolution work in the far ir. The instrument has a theoretical resolution of 0.007 cm(-1) and can be used with a tunable band pass filter system for the reduction of sampling points in a specific spectral region. Separations of 0.05 cm(-1) in the inversion spectrum of NH(3) in the 200-cm(-1) spectral region have been observed with about 1000 sampling points and splittings of 0.04 cm(-1) in the NO(2) spectrum at about 100 cm(-1).

Optical bistability of an aerosol particle.

The optical bistability of an aerosol particle is reported for the first time to the authors' knowledge. The mechanism for the effect is associated with the photothermal evaporation that accompanies the visible absorption by structure resonances.

Refractive-index measurements of single micron-sized carbon particles.

The differential scattering cross section for single carbon particles is measured in the visible. The data are mathematically inverted to obtain the complex index of refraction and particle radius.

Optical bistability of an aqueous aerosol particle detected through light scattering: theory and experiment.

We present a catastrophe-based graphic model for understanding the optical bistability (OB) of an aqueous aerosol particle detected in light scattering. The model is shown to be in good agreement with hidden resonance experiments and indicates that OB in such particles can occur at an incident power level of <50 x 10(-9) W. This threshold is controlled principally by the quality factor of morphological resonances and thermophysical properties of the particle. A catastrophe scheme for the bistability of solid particles is anticipated.