The non-equilibrium structural and dynamical properties of semiflexible polymers confined to two dimensions under oscillatory shear flow are investigated by Brownian multi-particle collision dynamics. Two different scenarios will be considered: Filaments with both fixed ends [1] and wall-anchored chains [2].The results of the numerical studies will be presented and discussed. 1] A. Lamura, R. G. Winkler, 'Tethered semiflexible polymer under large amplitude oscillatory shear', Polymers 11, 737 (2019) [2] A. Lamura, R. G. Winkler, G. Gompper, 'Wall-anchored semiflexible polymer under large oscillatory shear flow', pre-print (2021)

The non-equilibrium structural and dynamical properties of semiflexible polymers confined to two dimensions under oscillatory shear flow are investigated by Brownian multi-particle collision dynamics. Two different scenarios will be considered: Filaments with both fixed ends [1] and wall-anchored chains [2]. The results of the numerical studies will be presented and discussed. References [1] A. Lamura, R. G. Winkler Polymers 2019, 11, 737. DOI:10.3390/polym11040737 [2] A. Lamura, R. G. Winkler, G. Gompper pre-print 2021

We prove that on a smooth bounded set, the positive least energy solution of the Lane-Emden equation with sublinear power is isolated. As a corollary, we obtain that the first (Formula presented.) eigenvalue of the Dirichlet-Laplacian is not an accumulation point of the (Formula presented.) spectrum, on a smooth bounded set. Our results extend to a suitable class of Lipschitz domains, as well.

Riassumere gli ultimi 10 anni di attività del CUG dal 2011 al 2019 è stata nel tempo un'operazione complessa. Siamo riuscite, non senza fatica, e con uno sforzo congiunto, tenuto conto della pluralità delle voci che vi hanno partecipato, ad operare una sintesi soddisfacente, a fronte delle infinite competenze e attribuzioni, anche normative, dei Comitati di Garanzia, a scegliere le azioni positive più significative, svolte nel tempo e che costituiscono parte della nostra memoria storica. Abbiamo scelto di partire dalle iniziative avviate, a seguire quelle in corso e da implementare, dando spazio ai Progetti di ricerca di alcuni Istituti o Aree che hanno collaborato attivamente con il CUG su varie tematiche e che possiamo considerare un modello da tradurre ed esportare in altre Aree e realtà del Paese.

For a four-stream approximation of the kinetic model of radiative transfer with isotropic scattering, a numerical scheme endowed with both truly 2D well-balanced and diffusive asymptotic-preserving properties is derived, in the same spirit as what was done in [L. Gosse and G. Toscani, C. R. Math. Acad. Sci. Paris, 334 (2002), pp. 337-342] in the 1D case. Building on former results of Birkhoff and Abu-Shumays [J. Math. Anal. Appl., 28 (1969), pp. 211-221], it is possible to express 2D kinetic steady-states by means of harmonic polynomials, and this allows one to build a scattering S-matrix yielding a time-marching scheme. Such an S-matrix can be decomposed, as in [L. Gosse and N. Vauchelet, Numer. Math., 141 (2019), pp. 627-680], so as to deduce another scheme, well-suited for a diffusive approximation of the kinetic model, for which rigorous convergence can be proved. Challenging benchmarks are also displayed on coarse grids.

In this paper, we study the retrieval of water vapor profiles from simulated FORUM measurements. We show that the bias towards the a-priori introduced by the Optimal Estimation technique can be reduced by using larger errors for the a-priori. Reducing the strength of the a-priori may, however, cause unphysical oscillations in the resulting profiles because of the ill-conditioning of the retrieval problem. An a-posteriori regularization technique, the Iterative Variable Strength method, is thus applied to reduce the amplitude of the oscillations.

Wavelet methods are known to be very competitive in terms of denoising and compression, due to the simultaneous localization property of a function in time and frequency. However, boundary assumptions, such as periodicity or symmetry, generate bias and artificial wiggles which degrade overall accuracy. We present and compare some nonparametric estimation methods (wavelet and/or spline-based) designed to recover a one-dimensional piecewise-smooth regression function in both a fixed equidistant or not equidistant design regression model and a random design model.

Thermal infrared remote sensing measurements have greatly improved in terms of spectral, spatial, and temporal resolution. These improvements are producing a clearer picture of the land surface and Earth atmospheric composition than ever before. Nevertheless, the analysis of this big quantity of data presents important challenges due to incomplete temporal and spatial recorded information. The aim of the present paper is to discuss a methodology to retrieve missing values of some interesting geophysical variables on a spatial field retrieved from spatially scattered infrared satellite observations in order to yield level 3, regularly gridded, data. The technique is based on a 2-Dimensional (2D) Optimal Interpolation (OI) scheme and is derived from the broad class of Kalman filter or Bayesian estimation theory. The goodness of the approach has been tested on 15-min temporal resolution Spinning Enhanced Visible and Infrared Imager (SEVIRI) emissivity and surface temperature (ST) products over South Italy (land and sea), on Infrared Atmospheric Sounding Interferometer (IASI) atmospheric ammonia NH concentration over North Italy and carbon monoxide (CO), sulfur dioxide SO and NH concentrations over China. All these gases affect air quality. Moreover, sea surface temperature (SST) retrievals have been compared with gridded data from MODIS (Moderate-resolution Imaging Spectroradiometer) observations. For gases concentration we have considered data from 3 different emission inventories, that is, Emissions Database for Global Atmospheric Research v3.4.2 (EDGARv3.4.2), the Regional Emission inventory in ASiav3.1 (REASv3.1) and MarcoPolov0.1, plus an independent study. The results show the efficacy of the proposed strategy to better capture the daily cycle for surface parameters and to detect hotspots of severe emissions from gas sources affecting air quality such as CO and NH3 and, therefore, to yield valuable information on the variability of gas concentration to complete ground stations measurements.

The use of a mathematical model is proposed in order to denoise X-ray two-dimensional patterns. The method relies on a generalized diffusion equation whose diffusion constant depends on the image gradients. The numerical solution of the diffusion equation provides an efficient reduction of pattern noise as witnessed by the computed peak of signal-to-noise ratio. The use of experimental data with different inherent levels of noise allows us to show the success of the method even in the case, experimentally relevant, when patterns are blurred by Poissonian noise. The corresponding MatLab code for the numerical method is made available.

The phase-separation process of a binary mixture with order-parameter-dependent mobility under shear flow is numerically studied. The ordering is characterized by an alternate stretching and bursting of domains which produce oscillations in the physical observables. The amplitude of such modulations reduce in time when the mobility vanishes in the bulk phase, disfavoring the growth of bubbles coming from bursted domains. We propose two equations for the typical sizesR(x)andR(y)of domains finding the long-time behaviorsR(x)similar to t(5/4)andR(y)similar to t(1/4)in the flow and shear directions, respectively, in the case of surface diffusion. A reduction of the excess viscosity with increasing shear rate is observed in simulations.

Il documento offre un resoconto dettagliato dell'evento denominato 'Giornate CNR-IAC, di formazione alla comunicazione della scienza', tenutosi a Roma presso la Sede CNR-IAC di Via dei Taurini il 12-13 febbraio 2020, dalle fasi di preparazione e co-definizione del programma, allo svolgimento, all'analisi del questionario di gradimento. L'obiettivo delle giornate CNR-IAC di formazione alla comunicazione della scienza, co-organizzate da CNR-IAC, CNR-DSSTTA e CNR-Ufficio Comunicazione, è squello di migliorare le capacità di comunicazione scientifica dei ricercatori relativamente alle aree tematiche proprie dell'Istituto e verso differenti target, valorizzando lo scambio interdisciplinare e la pratica di esperienze di comunicazione interpersonale (verbale e non verbale), anche attraverso lo svolgimento di attività pratiche. Il lavoro svolto e i risultati raggiunti proiettano l'esperienza verso la definizione di un format da replicare e mettere a sistema a livello di singolo Istituto e di Ente.

In this paper, a reaction-diffusion prey-predator system including the fear effect of predator on prey population and group defense has been considered. The conditions for the onset of cross-diffusion-driven instability are obtained by linear stability analysis. The technique of multiple time scales is employed to deduce the amplitude equation near Turing bifurcation threshold by choosing the cross-diffusion coefficient as a bifurcation parameter. The stability analysis of these amplitude equations leads to the identification of various Turing patterns driven by the cross-diffusion, which are also investigated through numerical simulations.

In the past two decades, 7 coronaviruses have infected the human population, with two major outbreaks caused by SARS-CoV and MERS-CoV in the year 2002 and 2012, respectively. Currently, the entire world is facing a pandemic of another coronavirus, SARS-CoV-2, with a high fatality rate. The spike glycoprotein of SARS-CoV-2 mediates entry of virus into the host cell and is one of the most important antigenic determinants, making it a potential candidate for a vaccine. In this study, we have computationally designed a multi-epitope vaccine using spike glycoprotein of SARS-CoV-2. The overall quality of the candidate vaccine was validated in silico and Molecular Dynamics Simulation confirmed the stability of the designed vaccine. Docking studies revealed stable interactions of the vaccine with Toll-Like Receptors and MHC Receptors. The in silico cloning and codon optimization supported the proficient expression of the designed vaccine in E. coli expression system. The efficiency of the candidate vaccine to trigger an effective immune response was assessed by an in silico immune simulation. The computational analyses suggest that the designed multi-epitope vaccine is structurally stable which can induce specific immune responses and thus, can be a potential vaccine candidate against SARS-CoV-2. In the past two decades, 7 coronaviruses have infected the human population, with two major outbreaks caused by SARS-CoV and MERS-CoV in the year 2002 and 2012, respectively. Currently, the entire world is facing a pandemic of another coronavirus, SARS-CoV-2, with a high fatality rate. The spike glycoprotein of SARS-CoV-2 mediates entry of virus into the host cell and is one of the most important antigenic determinants, making it a potential candidate for a vaccine. In this study, we have computationally designed a multi-epitope vaccine using spike glycoprotein of SARS-CoV-2. The overall quality of the candidate vaccine was validated in silico and Molecular Dynamics Simulation confirmed the stability of the designed vaccine. Docking studies revealed stable interactions of the vaccine with Toll-Like Receptors and MHC Receptors. The in silico cloning and codon optimization supported the proficient expression of the designed vaccine in E. coli expression system. The efficiency of the candidate vaccine to trigger an effective immune response was assessed by an in silico immune simulation. The computational analyses suggest that the designed multi-epitope vaccine is structurally stable which can induce specific immune responses and thus, can be a potential vaccine candidate against SARS-CoV-2.

We generalize the nonstandard Euler and Heun schemes in order to provide explicit geometric numerical integrators for biochemical systems, here denoted as GeCo schemes, that preserve both positivity of the solutions and linear invariants. We relax the request on the order convergence of the denominator function for the first-order approximation and we let it depend on the step size also throughout the solution approximating values. The first-order variant is exact on a two-dimensional linear test problem. Moreover, we introduce a class of modified mGeCo(alpha) schemes and, by tuning the parameter alpha >= 1, we improve the numerical performance of GeCo integrators on some examples taken from the literature. A numerical comparison with BBKS and mBBKSschemes, which are implicit integrators, positive and conserve linear invariants, show the gain in efficiency of both GeCo and mGeCo(alpha) procedures as they generate similar errors with an explicit functional form. (C) 2019 IMACS. Published by Elsevier B.V. All rights reserved.

This Special Issue collects peer-reviewed original articles dealing with further developments of research results presented at MASCOT2018, the 15th IMACS/ISGG International Workshop. This one is the last edition in time of the MASCOT series of meetings, yearly organized since 2001 under the auspices of the Istituto per le Applicazioni del Calcolo (IAC) of the Consiglio Nazionale delle Ricerche (CNR), the principal organizer and co-sponsor. For a straightforward browsing of the Issue Contents all the articles are shortly introduced according to the following thematic Sections: Mathematical modeling in thermodynamics, Numerical methods for approximation, Numerical solution of partial differential equations, Data and signal processing, Subdivision schemes. Main advancements are delineated.

This Special Issue collects peer-reviewed original articles dealing with further developments of research results presented at MASCOT2018, the 15th IMACS/ISGG International Workshop. This one is the last edition in time of the MASCOT series of meetings, yearly organized since 2001 under the auspices of the Istituto per le Applicazioni del Calcolo (IAC) of the Consiglio Nazionale delle Ricerche (CNR), the principal organizer and co-sponsor.

The idea that individuals tend to choose a romantic partner following similarities on personality traits has always attracted much attention in the psychological literature, although results were controversial. We conducted a new data analysis approach to personality traits of 235 newlywed couples. Univariate analysis revealed that a neurotic husband is usually paired with a lesser extrovert and open wife. To figure out if this mating selection pattern may be translated in a mathematical predictive model a twofold approach was employed by using Partial Least Squares regression and machine learning algorithm. The experimental results demonstrate that marital assortment for personality is a multi-trait complementarity process but these data are unable to predict human mating.

Il 21/04/2020 ore 17.00 - 18.00 Canali Facebook e Youtube Comunicazione.Cnr TuttiInMusica con Light & Sound Project TuttiInMusica con Light & Sound Project Come legare insieme scienza, gioco, salute e Bulerías, un divertente "palo" del flamenco? Per rispondere abbiamo messo insieme: due scienziati che usano il gioco per fare divulgazione scientifica e didattica, un medico, una giornalista e un "bailaor". Una miscela unica e travolgente, come solo il flamenco può essere. E, sempre a "compás", Fabio Chiarello mostrerà "BeatWheel", un gioco da provare per scoprire il ritmo e la sua geometria. Saranno presenti Fabio Chiarello, ricercatore Cnr-Ifn di Roma, fisico e creatore di giochi divulgativi e animazioni su scienza, Armida Torreggiani, ricercatrice Cnr-Isof, Roberto Volpe, medico del Servizio prevenzione e protezione del Cnr di Roma e Dario Carbonelli, maestro di flamenco, ballerino e coreografo. Modera Silvia Mattoni, giornalista, responsabile Unità comunicazione e relazioni con il pubblico del Cnr, in regia Roberto Natalini direttore Cnr-Iac. Organizzato da: Unità comunicazione e relazioni con il pubblico Referente organizzativo: Per informazioni: Cnr - Unità Comunicazione e Relazioni con il Pubblico Responsabile: Silvia Mattoni

Il testo è un rapporto tecnico molto dettagliato sulle attività e i risultati del progetto Coffee BREAKS.

In recent papers, new sets of Sheffer and Brenke polynomials based on higher order Bell numbers have been studied, and several integer sequences related to them have been introduced. In this article other types of Sheffer polynomials are considered, by introducing the adjoint Poisson-Charlier and the adjoint Related polynomials.