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Book ; Online: Policy lessons from the Italian pandemic of Covid-19

Carcione, José M. / Ba, Jing

2023

Abstract: We analyze the management of the Italian pandemic during the five identified waves. We considered the following problems: (i) The composition of the CTS ("Scientific Technical Committee"), which was composed entirely of doctors, mainly virologists, ... ...

Abstract	We analyze the management of the Italian pandemic during the five identified waves. We considered the following problems: (i) The composition of the CTS ("Scientific Technical Committee"), which was composed entirely of doctors, mainly virologists, without mathematical epidemiologists, statisticians, physicists, etc. In fact, a pandemic has a behavior described by mathematical, stochastic and probabilistic criteria; (ii) Political interference in security measures and media propaganda; (iii) The initial stages of the vaccination campaign, ignoring the age factor, and (iv) The persistence of the pandemic due to the population unvaccinated (anti-vax or "no-vax"), which amounts to about six to seven million people, including 10% of anti-vax doctors.
Keywords	Physics - Physics and Society ; Quantitative Biology - Populations and Evolution
Publishing date	2023-03-11
Publishing country	us
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: A numerical extension of White's theory of P-wave attenuation to non-isothermal poroelastic media.

Zapata, Naddia D Arenas / Santos, Juan E / Savioli, Gabriela B / Carcione, José M / Ba, Jing

The Journal of the Acoustical Society of America

2024 Volume 155, Issue 2, Page(s) 1486–1491

Abstract: Mesoscopic P-wave attenuation in layered, partially saturated thermo-poroelastic media is analyzed by combining the theories of Biot poroelasticity and Lord-Shulman thermoelasticity (BLS). The attenuation is quantified by estimating the quality factor Q. ...

Abstract	Mesoscopic P-wave attenuation in layered, partially saturated thermo-poroelastic media is analyzed by combining the theories of Biot poroelasticity and Lord-Shulman thermoelasticity (BLS). The attenuation is quantified by estimating the quality factor Q. The mesoscopic attenuation effect, commonly referred to as wave-induced fluid flow (WIFF), is the process that converts fast compressional and shear waves into slow diffusive Biot waves at mesoscopic heterogeneities larger than the pore scale, but much smaller than the dominant wavelengths. This effect was first modeled in White's isothermal theory by quantifying the seismic response of a periodic sequence of planar porous layers that are alternately saturated with gas or water. This work presents a numerical extension of White's theory for the non-isothermal case in this type of sequence. For this purpose, an initial-boundary-value problem (IBVP) for the BLS wave propagation equations is solved using the finite element method, where the particle velocity field is recorded at uniformly distributed receivers. The quality factor is estimated using spectral-ratio and frequency-shift methods. The Q-estimates show that thermal effects influence the attenuation of the P-wave and the velocity dispersion compared to the isothermal case.
Language	English
Publishing date	2024-02-16
Publishing country	United States
Document type	Journal Article
ZDB-ID	219231-7
ISSN	1520-8524 ; 0001-4966
ISSN (online)	1520-8524
ISSN	0001-4966
DOI	10.1121/10.0024979
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Article ; Online: A simulation of a COVID-19 epidemic based on a deterministic SEIR model

Carcione, Jose' M

medRxiv

Abstract: An epidemic disease caused by a new coronavirus has spread in Northern Italy with a strong contagion rate. We implement an SEIR model to compute the infected population and number of casualties of this epidemic. The example may ideally regard the ... ...

Abstract	An epidemic disease caused by a new coronavirus has spread in Northern Italy with a strong contagion rate. We implement an SEIR model to compute the infected population and number of casualties of this epidemic. The example may ideally regard the situation in the Italian Region of Lombardy, where the epidemic started on February 25, but by no means attempts to perform a rigorous case study in view of the lack of suitable data and uncertainty of the different parameters, namely, the variation of the degree of home isolation and social distancing as a function of time, the number of initially exposed individuals and infected people, the incubation and infection periods and the fatality rate. First, we perform an analysis of the results of the model, by varying the parameters and initial conditions (in order the epidemic to start, there should be at least one exposed or one infected human). Then, we consider the Lombardy case and calibrate the model with the number of dead individuals to date (April 19, 2020) and constraint the parameters on the basis of values reported in the literature. The peak occurs at day 37 (April 1) approximately, when there is a rapid decrease, with a reproduction ratio R0 = 3 initially, 1.38 at day 22 and 0.64 after day 35, indicating different degrees of lockdown. The predicted death toll is almost 14000 casualties, with 2.4 million infected individuals at the end of the epidemic. The incubation period providing a better fit of the dead individuals is 4.25 days and the infection period is 4 days, with a fatality rate of 0.00144/day [values based on the reported (official) number of casualties]. The infection fatality rate (IFR) is 0.57 %, and 2.36 % if twice the reported number of casualties is assumed. However, these rates depend on the initially exposed individuals. If approximately nine times more individuals are exposed, there are three times more infected people at the end of the epidemic and IFR = 0.47 %. If we relax these constraints and use a wider range of lower and upper bounds for the incubation and infection periods, we observe that a higher incubation period (13 versus 4.25 days) gives the same IFR (0.6 versus 0.57 %), but nine times more exposed individuals in the first case. Therefore, a precise determination of the fatality rate is subject to the knowledge of the characteristics of the epidemic. We plan to perform again these calculations and publish a short note when the epidemic is over and the complete and precise data is available. Besides the specific example, the analysis proposed in this work shows how isolation measures, social distancing and knowledge of the diffusion conditions help us to understand the dynamics of the epidemic. Hence, the importance to quantify the process to verify the effectiveness of the isolation.
Keywords	covid19
Language	English
Publishing date	2020-04-24
Publisher	Cold Spring Harbor Laboratory Press
Document type	Article ; Online
DOI	10.1101/2020.04.20.20072272
Database	COVID19

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Article ; Online: A simulation of a COVID-19 epidemic based on a deterministic SEIR model

Carcione, Jose' M

Abstract	An epidemic disease caused by a new coronavirus has spread in Northern Italy with a strong contagion rate. We implement an SEIR model to compute the infected population and number of casualties of this epidemic. The example may ideally regard the situation in the Italian Region of Lombardy, where the epidemic started on February 25, but by no means attempts to perform a rigorous case study in view of the lack of suitable data and uncertainty of the different parameters, namely, the variation of the degree of home isolation and social distancing as a function of time, the number of initially exposed individuals and infected people, the incubation and infection periods and the fatality rate. First, we perform an analysis of the results of the model, by varying the parameters and initial conditions (in order the epidemic to start, there should be at least one exposed or one infected human). Then, we consider the Lombardy case and calibrate the model with the number of dead individuals to date (April 19, 2020) and constraint the parameters on the basis of values reported in the literature. The peak occurs at day 37 (April 1) approximately, when there is a rapid decrease, with a reproduction ratio R0 = 3 initially, 1.38 at day 22 and 0.64 after day 35, indicating different degrees of lockdown. The predicted death toll is almost 14000 casualties, with 2.4 million infected individuals at the end of the epidemic. The incubation period providing a better fit of the dead individuals is 4.25 days and the infection period is 4 days, with a fatality rate of 0.00144/day [values based on the reported (official) number of casualties]. The infection fatality rate (IFR) is 0.57 %, and 2.36 % if twice the reported number of casualties is assumed. However, these rates depend on the initially exposed individuals. If approximately nine times more individuals are exposed, there are three times more infected people at the end of the epidemic and IFR = 0.47 %. If we relax these constraints and use a wider range of lower and upper bounds for the incubation and infection periods, we observe that a higher incubation period (13 versus 4.25 days) gives the same IFR (0.6 versus 0.57 %), but nine times more exposed individuals in the first case. Therefore, a precise determination of the fatality rate is subject to the knowledge of the characteristics of the epidemic. We plan to perform again these calculations and publish a short note when the epidemic is over and the complete and precise data is available. Besides the specific example, the analysis proposed in this work shows how isolation measures, social distancing and knowledge of the diffusion conditions help us to understand the dynamics of the epidemic. Hence, the importance to quantify the process to verify the effectiveness of the isolation.
Keywords	covid19
Publisher	MedRxiv; WHO
Document type	Article ; Online
DOI	10.1101/2020.04.20.20072272
Database	COVID19

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Article ; Online: P- and S-wave simulation using a Cole-Cole model to incorporate thermoelastic attenuation and dispersion.

Carcione, José M / Picotti, Stefano / Ba, Jing

The Journal of the Acoustical Society of America

2021 Volume 149, Issue 3, Page(s) 1946

Abstract: In thermoelastic wave attenuation, such as that caused by heterogeneities much smaller than the wavelength, e.g., Savage theory of spherical pores, the shape of the relaxation peak differs from that of the Zener (or standard linear solid) mechanical ... ...

Abstract	In thermoelastic wave attenuation, such as that caused by heterogeneities much smaller than the wavelength, e.g., Savage theory of spherical pores, the shape of the relaxation peak differs from that of the Zener (or standard linear solid) mechanical model. In these effective homogeneous media, the anelastic behavior is better represented by a stress-strain relation based on fractional derivatives; particularly, P- and S-wave dispersion and attenuation is well described by a Cole-Cole equation. We propose a time-domain algorithm for wave propagation based on the Grünwald-Letnikov numerical derivative and the Fourier pseudospectral method to compute the spatial derivatives. As an example, we consider Savage theory and verify the algorithm by comparison with the analytical solution in homogeneous media based on the frequency-domain Green function. Moreover, we illustrate the modeling performance with wave propagation in a two half-space medium where one section is lossless and the other is a Cole-Cole medium. This apparently simple example, which does not have an analytical solution, shows the complexity of the wavefield that characterizes a single flat interface.
Language	English
Publishing date	2021-03-25
Publishing country	United States
Document type	Journal Article
ZDB-ID	219231-7
ISSN	1520-8524 ; 0001-4966
ISSN (online)	1520-8524
ISSN	0001-4966
DOI	10.1121/10.0003749
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Article ; Online: Stress Effects on Wave Velocities of Rocks: Contribution of Crack Closure, Squirt Flow and Acoustoelasticity

Wei, Yijun / Ba, Jing / Carcione, José M.

Journal of Geophysical Research: Solid Earth. 2022 Oct., v. 127, no. 10 p.e2022JB025253-

2022

Abstract: The elastic properties of rocks depend on the mineral constituents, pore structure, saturating fluids, and stress (loading) conditions. To study these properties, we measured ultrasonic P‐ and S‐wave velocities as a function of the differential ( ... ...

Abstract	The elastic properties of rocks depend on the mineral constituents, pore structure, saturating fluids, and stress (loading) conditions. To study these properties, we measured ultrasonic P‐ and S‐wave velocities as a function of the differential (confining minus pore) pressure and propose an unrelaxed double‐porosity acoustoelasticity model, which generalizes the single‐porosity one. The new approach includes the effects of crack closure, based on the David‐Zimmerman model, and the squirt‐flow mechanism, based on the Gurevich model. When cracks are open at low differential pressures, their properties dominate the wave velocity variations, followed by the squirt‐flow mechanism. Then, a transition occurs, where cracks partially close, and the squirt‐flow effect vanishes. At high pressures, cracks close and acoustoelasticity effects prevail. This behavior is observed in sedimentary rocks, whereas in granites, which have a low crack content, the acoustoelastic effect is dominant at all pressures.
Keywords	geophysics ; models ; research ; ultrasonics
Language	English
Dates of publication	2022-10
Publishing place	John Wiley & Sons, Ltd
Document type	Article ; Online
Note	JOURNAL ARTICLE
ISSN	2169-9313
DOI	10.1029/2022JB025253
Database	NAL-Catalogue (AGRICOLA)

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Article ; Online: Reflection and Transmission of Inhomogeneous Plane Waves in Thermoelastic Media

Wanting Hou / Li-Yun Fu / José M. Carcione / Tongcheng Han

Frontiers in Earth Science, Vol

2022 Volume 10

Abstract: We study the reflection and transmission coefficients of plane waves incident at an interface between two isotropic thermoelastic half spaces and compare them with those of the elastic case. The models include the classical-Biot (B) and extended Lord- ... ...

Abstract	We study the reflection and transmission coefficients of plane waves incident at an interface between two isotropic thermoelastic half spaces and compare them with those of the elastic case. The models include the classical-Biot (B) and extended Lord-Shulman (LS) theories, and predict reflected and transmitted fast-compressional (P), thermal (T) and shear (S) waves. The coefficients are formulated in terms of incidence and inhomogeneity angles, medium properties and potential functions. We consider different incident wave types and inhomogeneity angles to analyze the magnitude, phase and energy ratio of the plane waves, and perform a comparison with the isothermal (elastic) theory. The thermoelastic and elastic models predict different energy partitions between the P and S modes, satisfying the conservation of energy. The LS model exhibits higher T-wave thermal attenuation with increasing inhomogeneity angle at high frequencies, accordingly predicting more interference energy. The angle affects the energy partitions, particularly at the critical angle and near grazing incidence for an incident P wave, which satisfies the conservation of energy. Beyond the critical angle, the energy flux perpendicular to the interface of the isothermal model vanishes, while it is significant in the thermoelastic case. The T-wave magnitudes increase when the thermal conductivity (relaxation time) increases.
Keywords	thermoelasticity and elasticity ; reflection and transmission coefficients ; energy partitions ; inhomogeneous plane waves ; attenuation angle ; Science ; Q
Subject code	535
Language	English
Publishing date	2022-04-01T00:00:00Z
Publisher	Frontiers Media S.A.
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Numerical simulation of wave-induced fluid flow seismic attenuation based on the Cole-Cole model.

Picotti, Stefano / Carcione, José M

The Journal of the Acoustical Society of America

2017 Volume 142, Issue 1, Page(s) 134

Abstract: The acoustic behavior of porous media can be simulated more realistically using a stress-strain relation based on the Cole-Cole model. In particular, seismic velocity dispersion and attenuation in porous rocks is well described by mesoscopic-loss models. ...

Abstract	The acoustic behavior of porous media can be simulated more realistically using a stress-strain relation based on the Cole-Cole model. In particular, seismic velocity dispersion and attenuation in porous rocks is well described by mesoscopic-loss models. Using the Zener model to simulate wave propagation is a rough approximation, while the Cole-Cole model provides an optimal description of the physics. Here, a time-domain algorithm is proposed based on the Grünwald-Letnikov numerical approximation of the fractional derivative involved in the time-domain representation of the Cole-Cole model, while the spatial derivatives are computed with the Fourier pseudospectral method. The numerical solution is successfully tested against an analytical solution. The methodology is applied to a model of saline aquifer, where carbon dioxide (CO
Language	English
Publishing date	2017-08-01
Publishing country	United States
Document type	Journal Article
ZDB-ID	219231-7
ISSN	1520-8524 ; 0001-4966
ISSN (online)	1520-8524
ISSN	0001-4966
DOI	10.1121/1.4990965
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Article ; Online: Waves at a fluid-solid interface: Explicit versus implicit formulation of boundary conditions using a discontinuous Galerkin method.

Shukla, Khemraj / Carcione, José M / Hesthaven, Jan S / L'heureux, Elizabeth

The Journal of the Acoustical Society of America

2020 Volume 147, Issue 5, Page(s) 3136

Abstract: An accurate solution of the wave equation at a fluid-solid interface requires a correct implementation of the boundary condition. Boundary conditions at fluid-solid interface require continuity of the normal component of particle velocity and traction, ... ...

Abstract	An accurate solution of the wave equation at a fluid-solid interface requires a correct implementation of the boundary condition. Boundary conditions at fluid-solid interface require continuity of the normal component of particle velocity and traction, whereas the tangential components vanish. A main challenge is to model interface waves, namely, the Scholte and leaky Rayleigh waves. This study uses a nodal discontinuous Galerkin (dG) finite-element method with the medium discretized using an unstructured uniform triangular meshes. The natural boundary conditions in the dG method are implemented by (1) using an explicit upwind numerical flux and (2) by using an implicit penalty flux and setting the modulus of rigidity of the acoustic medium to zero. The accuracy of these methods is evaluated by comparing the numerical solutions with analytical ones, with source and receiver at and away from the interface. The study shows that the solutions obtained from the explicit and implicit boundary conditions provide the correct results. The stability of the dG scheme is determined by the numerical flux, which also implements the boundary conditions by unifying the numerical solution at shared edges of the elements in an energy stable manner.
Language	English
Publishing date	2020-06-02
Publishing country	United States
Document type	Journal Article
ZDB-ID	219231-7
ISSN	1520-8524 ; 0001-4966
ISSN (online)	1520-8524
ISSN	0001-4966
DOI	10.1121/10.0001170
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Article: A Simulation of a COVID-19 Epidemic Based on a Deterministic SEIR Model.

Carcione, José M / Santos, Juan E / Bagaini, Claudio / Ba, Jing

Frontiers in public health

2020 Volume 8, Page(s) 230

Abstract: An epidemic disease caused by a new coronavirus has spread in Northern Italy with a strong contagion rate. We implement an SEIR model to compute the infected population and the number of casualties of this epidemic. The example may ideally regard the ... ...

Abstract	An epidemic disease caused by a new coronavirus has spread in Northern Italy with a strong contagion rate. We implement an SEIR model to compute the infected population and the number of casualties of this epidemic. The example may ideally regard the situation in the Italian Region of Lombardy, where the epidemic started on February 24, but by no means attempts to perform a rigorous case study in view of the lack of suitable data and the uncertainty of the different parameters, namely, the variation of the degree of home isolation and social distancing as a function of time, the initial number of exposed individuals and infected people, the incubation and infectious periods, and the fatality rate. First, we perform an analysis of the results of the model by varying the parameters and initial conditions (in order for the epidemic to start, there should be at least one exposed or one infectious human). Then, we consider the Lombardy case and calibrate the model with the number of dead individuals to date (May 5, 2020) and constrain the parameters on the basis of values reported in the literature. The peak occurs at day 37 (March 31) approximately, with a reproduction ratio
MeSH term(s)	COVID-19/epidemiology ; COVID-19/mortality ; Communicable Disease Control ; Computer Simulation ; Humans ; Italy/epidemiology ; Models, Statistical ; SARS-CoV-2
Keywords	covid19
Language	English
Publishing date	2020-05-28
Publishing country	Switzerland
Document type	Journal Article
ZDB-ID	2711781-9
ISSN	2296-2565
ISSN	2296-2565
DOI	10.3389/fpubh.2020.00230
Database	MEDical Literature Analysis and Retrieval System OnLINE

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