Mathematical modeling and investigation on the role of demography and contact patterns in social distancing measures effectiveness in COVID-19 dissemination.

In this article, we investigate the importance of demography and contact patterns in determining the spread of COVID-19 and to the effectiveness of social distancing policies. We investigate these questions proposing an augmented epidemiological model with an age-structured model, with the population divided into susceptible (S), exposed (E), asymptomatic infectious (A), hospitalized (H), symptomatic infectious (I) and recovered individuals (R), to simulate COVID-19 dissemination. The simulations were carried out using six combinations of four types of isolation policies (work restrictions, isolation of the elderly, community distancing and school closures) and four representative fictitious countries generated over alternative demographic transition stage patterns (aged developed, developed, developing and least developed countries).

Statistical physics of two-temperature rotational energy distributions in stationary plasmas.

Two-temperature rotational energy distributions from rarefied diatomic molecules are very often observed in laboratory plasmas. There has been much debate over the years about the physical meaning of this kind of rotational energy distributions and the associated statistical physics. We show here that under certain reasonable assumptions and constraints the condition of Shannon-Jaynes entropy maximization may produce a two-temperature distribution.

Kinetic description of non-Boltzmann OH rotational distribution in nonequilibrium stationary plasmas.

We present a model that describes the departure from equilibrium of the OH(A) rotational level distribution in collisional plasmas. In this model, the OH(A) rotational state densities are governed by a rate equation including: (i) a balanced rotational energy transfer process with the buffer gas species; (ii) unbalanced exothermic reactions, which pump rotationally excited states into the system. Based on the prior assumptions, we formally derive a model function describing the non-Boltzmann distribution.

Causes of plasma column contraction in surface-wave-driven discharges in argon at atmospheric pressure.

In this work we compute the main features of a surface-wave-driven plasma in argon at atmospheric pressure in view of a better understanding of the contraction phenomenon. We include the detailed chemical kinetics dynamics of Ar and solve the mass conservation equations of the relevant neutral excited and charged species. The gas temperature radial profile is calculated by means of the thermal diffusion equation.