arXiv subjects

José R. C. Piqueira

Publications and source records attributed to José R. C. Piqueira.

3 recordsLinked to original sources

arXiv2021

SIRSi-Vaccine dynamical model for Covid-19 pandemic

The Severe Acute Respiratory Syndrome Corona Virus 2 (SARS-CoV-2), or Covid-19, burst into a pandemic in the beginning of 2020. An unprecedented worldwide effort involving academic institutions, regulatory agencies and industry is facing the challenges imposed by the rapidly spreading disease. Emergency use authorization for vaccines were granted in the beginning of December 2020 in Europe and nine days later in the United States. The urge for vaccination started a race, forcing governs and health care agencies to take decisions on the fly regarding the vaccination strategy and logistics. So far, the vaccination strategies and non-pharmaceutical interventions, such as social distancing and the use of face masks, are the only efficient actions to stop the pandemic. In this context, it is of fundamental importance to understand the dynamical behavior of the Covid-19 spread along with possible vaccination strategies. In this work a Susceptible - Infected - Removed - Sick with vaccination (SIRSi-Vaccine) model is proposed. In addtion, the SIRSi-Vaccine model also accounts for unreported, or asymptomatic, cases and the possibility of temporary immunity, either after infection or vaccination. Disease free and endemic equilibrium points existence conditions are determined in the (! ? ?) vaccine-effort and social distancing parameter space. The model is adjusted to the data from São Paulo, Santos and Campinas, three major cities in the State of São Paulo, Brazil.

math.DS↗

arXiv2020

Compartmental model with loss of immunity: analysis and parameters estimation for Covid-19

The outbreak of Covid-19 led the world to an unprecedent health and economical crisis. In an attempt to responde to this emergency researchers worldwide are intensively studying the Covid-19 pandemic dynamics. In this work, a SIRSi compartmental model is proposed, which is a modification of the known classical SIR model. The proposed SIRSi model considers differences in the immunization within a population, and the possibility of unreported or asymptomatic cases. The model is adjusted to three major cities of São Paulo State, in Brazil, namely, São Paulo, Santos and Campinas, providing estimates on the duration and peaks of the outbreak.

q-bio.PE↗

arXiv2019

Multiscale Approach to Fluid-Solid Interfaces: An overview of methodologies coupling fluid mechanics to molecular dynamics and quantum theory

In conventional fluid mechanics, the chemical composition and thermodynamic state of a fluid-solid interface are not considered when establishing velocity-field boundary conditions. As a consequence, fluid simulations are usually not able to generate different outputs when interfacial materials are varied. By considering an atomistic description of matter, theoretical determination of material-specific boundary conditions becomes possible, thereby providing an improved alternative to the completely-invariant no-slip condition. Such a scheme constitutes a multiscale approach to fluid dynamics involving essentially two transitions between space-time scales: the first concerns the derivation of macroscopic boundary conditions by means of molecular assessment of slip lengths; the second concerns the construction of interatomic force fields, required by molecular dynamics simulations, from quantum theory. In this introductory overview we discuss some of the fundamental aspects of these problems.

physics.flu-dyn↗