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2019 Articolo in rivista metadata only access

Game of neutrophils: modeling the balance between apoptosis and necrosis

Presbitero Alva ; Mancini Emiliano ; Castiglione Filippo ; Krzhizhanovskaya Valeria V ; Quax Rick

We show that by using evolutionary game theory, we are able to formulate a game that predicts the percentage of necrosis and apoptosis when exposed to various levels of insults. Background: Neutrophils are one of the key players in the human innate immune system (HIIS). In the event of an insult where the body is exposed to inflammation triggering moieties (ITMs), neutrophils are mobilized towards the site of insult and antagonize the inflammation. If the inflammation is cleared, neutrophils go into a programmed death called apoptosis. However, if the insult is intense or persistent, neutrophils take on a violent death pathway called necrosis, which involves the rupture of their cytoplasmic content into the surrounding tissue that causes local tissue damage, thus further aggravating inflammation. This seemingly paradoxical phenomenon fuels the inflammatory process by triggering the recruitment of additional neutrophils to the site of inflammation, aimed to contribute to the complete neutralization of severe inflammation. This delicate balance between the cost and benefit of the neutrophils' choice of death pathway has been optimized during the evolution of the innate immune system. The goal of our work is to understand how the tradeoff between the cost and benefit of the different death pathways of neutrophils, in response to various levels of insults, has been optimized over evolutionary time by using the concepts of evolutionary game theory.

Neutrophils Evolutionary game theory Apoptosis Necrosis Mean-field approximation Cellular automata
2019 Abstract in Atti di convegno metadata only access

Bootstrap AMG in spectral clustering

Bootstrap AMG Spectral Clustering
2019 Articolo in rivista metadata only access

A new set of Sheffer-Bell polynomials and logarithmic numbers

Gabriella Bretti ; Pierpaolo Natalini ; Paolo Emilio Ricci

In a recent paper, we have introduced new sets of Sheffer and Brenke polynomial sequences based on higher order Bell numbers. In this paper, by using a more compact notation, we show another family of exponential polynomials belonging to the Sheffer class, called, for shortness, Sheffer-Bell polynomials. Furthermore, we introduce a set of logarithmic numbers, which are the counterpart of Bell numbers and their extensions.

Higher order Bell
2019 Articolo in rivista open access

Strong convergence of a vector-BGK model to the incompressible Navier-Stokes equations via the relative entropy method

The aim of this paper is to prove the strong convergence of the solutions to a vector-BGK model under the diffusive scaling to the incompressible Navier-Stokes equations on the two-dimensional torus. This result holds in any interval of time [0,T], with T>0. We also provide the global in time uniform boundedness of the solutions to the approximating system. Our argument is based on the use of local in time H-estimates for the model, established in a previous work, combined with the L-relative entropy estimate and the interpolation properties of the Sobolev spaces.

Vector-BGK models Incompressible Navier-Stokes equations Dissipative entropy Relative entropy Diffusive relaxation
2019 Articolo in rivista metadata only access

Nonresonant bilinear forms for partially dissipative hyperbolic systems violating the Shizuta-Kawashima condition

We consider a simple example of a partially dissipative hyperbolic system violating the Shizuta-Kawashima condition, ie such that some eigendirections do not exhibit dissipation at all. In the space-time resonances framework introduced by Germain, Masmoudi and Shatah, we prove that, when the source term has a Nonresonant Bilinear Form, as proposed by Pusateri and Shatah CPAM 2013, the formation of singularities is prevented, despite the lack of dissipation. This allows us to show that smooth solutions to this preliminary case-study model exist globally in time.

Partially dissipative hyperbolic systems Shizuta-Kawashima condition space-time resonances dispersion.
2019 Articolo in rivista restricted access

Revisitation of a Tartar's result on a semilinear hyperbolic system with null condition

Roberta Bianchini ; Gigliola Staffilani

We revisit a method introduced by Tartar for proving global well-posedness of a semilinear hyperbolic system with null quadratic source in one space dimension. A remarkable point is that, since no dispersion effect is available for 1D hyperbolic systems, Tartar's approach is entirely based on spatial localization and finite speed of propagation.

null condition semilinear hyperbolic system
2019 Articolo in rivista open access

A pathological example in nonlinear spectral theory

Brasco L ; Franzina G

We construct an open set ? ? ? R on which an eigenvalue problem for the p-Laplacian has no isolated first eigenvalue and the spectrum is not discrete. The same example shows that the usual Lusternik-Schnirelmann minimax construction does not exhaust the whole spectrum of this eigenvalue problem.

p-Laplacian Nonlinear eigenvalue problems Lusternik-Schnirelmann theory
2019 Articolo in rivista open access

Non-local torsion functions and embeddings

Given (Formula presented.), we discuss the embedding of (Formula presented.) in (Formula presented.). In particular, for (Formula presented.) we deduce its compactness on all open sets (Formula presented.) on which it is continuous. We then relate, for all q up the fractional Sobolev conjugate exponent, the continuity of the embedding to the summability of the function solving the fractional torsion problem in (Formula presented.) in a suitable weak sense, for every open set (Formula presented.). The proofs make use of a non-local Hardy-type inequality in (Formula presented.), involving the fractional torsion function as a weight.

Sobolev embedding; Torsional rigidity; Hardy inequality; Non-local Equations
2019 Articolo in rivista open access

Lamellar ordering, droplet formation and phase inversion in exotic active emulsions

F. Bonelli ; L. N. Carenza ; G. Gonnella ; D. Marenduzzo ; E. Orlandini ; A. Tiribocchi

We study numerically the behaviour of a two-dimensional mixture of a passive isotropic fluid and an active polar gel, in the presence of a surfactant favouring emulsification. Focussing on parameters for which the underlying free energy favours the lamellar phase in the passive limit, we show that the interplay between nonequilibrium and thermodynamic forces creates a range of multifarious exotic emulsions. When the active component is contractile (e.g., an actomyosin solution), moderate activity enhances the efficiency of lamellar ordering, whereas strong activity favours the creation of passive droplets within an active matrix. For extensile activity (occurring, e.g., in microtubule-motor suspensions), instead, we observe an emulsion of spontaneously rotating droplets of different size. By tuning the overall composition, we can create high internal phase emulsions, which undergo sudden phase inversion when activity is switched off. Therefore, we find that activity provides a single control parameter to design composite materials with a strikingly rich range of morphologies.

Active emulsions Phase inversion Lattice Boltzmann
2019 Rapporto tecnico metadata only access

Report Attività Svolte

Relazione fine primo anno assegno di ricerca CNR-IAC di tipologia A) "assegni professionalizzanti" nell'ambito del progetto europeo ERC Advanced Grant "COPMAT" (GA N. 739964), con elenco attività svolte e analisi dei risultati raggiunti e dei prossimi passi. Periodo 18/06/2018 - 17/06/2019.

attività COPMAT
2019 Rapporto di progetto metadata only access

Final Report of the ESA-ESRIN Contract no. 4000112093/14/I-LG - Support to MIPAS Level 2 processor Verification and Validation - Phase F

P Raspollini ; F Barbara ; B Carli ; S Ceccherini ; M Gai ; N Zoppetti ; M Ridolfi ; J M Flaud ; E Castelli ; B M Dinelli ; E Papandrea ; D Moore ; J Remedios ; A Dudhia ; M Kiefer ; G Wetzel ; H Oelhaf ; M López Puertas ; B Funke ; L Sgheri ; D Hubert ; A Keppens

Riporta i principali risultati ottenuti nell'ambito del progetto: "Support to MIPAS Level 2 processor Verification and Validation - Phase F", Contratto ESA 4000112093/14/I-LG, cioe' la messa a punto del codice ORM_V8 da utilizzare per la rianalisi di livello 2 dell'intera missione di MIPAS/ENVISAT, il dataset processato, i test di verifica e di validazione dei prodotti di Livello 2 generati.

MIPAS Envisat Satellite Earth Observation Final Report
2019 Contributo in Atti di convegno metadata only access

Potential predictors of type-2 diabetes risk: machine learning, synthetic data and wearable health devices

In this study, the results of 46170 simulations corresponding to the same number of virtual subjects, experiencing different lifestyle conditions, are analysed for the construction of a statistical model able to recapitulate the simulated dynamics. Investigation about the mechanisms involved in the onset of type 2 diabetes in absence of familiarity is the focus of a research project which has led to the development of a computational model that recapitulates the aetiology of the disease. The model simulates the metabolic and immunological alterations related to type-2 diabetes associated to several clinical, physiological and behavioural characteristics of representative virtual patients.

T2D diabetes mathematical and computational modelling simulation machine learning random forest
2019 Abstract in Atti di convegno metadata only access

La partecipazione nei metodi delphi-simili

partecipazione delphi metodo
2019 Rapporto tecnico metadata only access

INdAM Workshop: Mathematical modeling and Analysis of degradation and restoration in Cultural Heritage

Bonetti Elena ; Cavaterra Cecilia ; Roberto Natalini ; De Filippo Barbara ; Di Berardo Mara

Report del convegno "MACH2019", svolto a Roma in data 25-29 marzo 2019, co-organizzato da Università degli Studi di Milano, Istituto per le Applicazioni del Calcolo M. Picone, Università degli Studi di Sassari, finanziato da Università degli Studi di Milano, Istituto per le Applicazioni del Calcolo M. Picone e INdAM (Istituto Nazionale di Alta Matematica). Obiettivo: costruire un ponte permanente tra esperti del patrimonio culturale e la comunità matematica. Il report raccoglie info sul convegno (focus, topics, data e location, organizzatori, speaker e partecipanti sponsors e attività extra), dati sui partecipanti, agenda ed abstract e prossimi passi (proceedings). Anno: 2019 (8 aprile)

INdAM Mathematical modeling cultural herigate
2019 Articolo in rivista metadata only access

Compact Ground-Based Interferometric Synthetic Aperture Radar Short-range structural monitoring

Anghel Andrei ; Tudose Mihai ; Cacoveanu Remus ; Datcu Mihai ; Nico Giovanni ; Masci Olimpia ; Dongyang Ao ; Tian Weiming ; Hu Cheng ; Ding Zegang ; Nies Holger ; Loffeld Otmar ; Atencia David ; Huaman Samuel G ; Medella Aleksander ; Moreira Joao

Recently, structural monitoring by radar remote sensing has become more necessary for both economic and security reasons. Infrastructure monitoring with no incorporated deformation sensors (e.g., old generation water dams for which regulations did not impose monitoring capabilities) is usually performed by regular in situ topographic surveys. However, these surveys cannot be performed very often, and alternative methods are desirable. A feasible nonintrusive way to monitor such a structure is with interferometric synthetic aperture radar (SAR) data that can be acquired with monostatic/bistatic sensors.

radar
2019 Articolo in rivista metadata only access

3-D Ground-Based Imaging Radar Based on C-Band Cross-MIMO Array and Tensor Compressive Sensing

Feng Weike ; Friedt JeanMichel ; Nico Giovanni ; Sato Motoyuki

We designed a ground-based radar system with a C-band 2-D cross multiple input multiple output (MIMO) array for 3-D imaging and displacement estimation purposes. For this system, we developed a far-field pseudo-polar image format algorithm using pseudo-polar spherical coordinate. The use of a tensor compressive sensing technique allows to focus under-sampled raw data and to optimize the data acquisition time and memory usage. A novel algorithm, named as tensor-based iterative adaptive approach, is proposed for the effective and efficient reconstruction of sparse targets with a reduced level of sidelobes. Experimental results validate the designed radar system and the proposed algorithms.

3-D imaging compressive sensing (CS) cross multiple input multiple output (MIMO) iterative adaptive approach (IAA) pseudo-polar spherical coordinate
2019 Articolo in rivista open access

InSAR Meteorology: High-Resolution Geodetic Data Can Increase Atmospheric Predictability

Miranda P M A ; Mateus P ; Nico G ; Catalao J ; Tome R ; Nogueira M

Plain Language Summary Weather forecasts will never be perfect because our models are simplified representations of nature and our observations of the atmosphere are inaccurate. In this study we show, nevertheless, that it is possible to improve such forecasts by interpreting the atmospheric signals in spaceborne radar observations of the Earth surface, indicative of the distribution of water vapor. Better and more detailed maps of water vapor are found to lead to better forecasts not just of water vapor but also of precipitation. A two and a half years assessment covering a wide range of weather conditions in a very well monitored region near the Appalachian Mountains, USA, suggests that the proposed methodology has a significant impact in the quality of the forecasts and could easily be implemented. The present study assesses the added value of high-resolution maps of precipitable water vapor, computed from synthetic aperture radar interferograms , in short-range atmospheric predictability. A large set of images, in different weather conditions, produced by Sentinel-1A in a very well monitored region near the Appalachian Mountains, are assimilated by the Weather Research and Forecast (WRF) model. Results covering more than 2 years of operation indicate a consistent improvement of the water vapor predictability up to a range comparable with the transit time of the air mass in the synthetic aperture radar interferograms footprint, an overall improvement in the forecast of different precipitation events, and better representation of the spatial distribution of precipitation. This result highlights the significant potential for increasing short-range atmospheric predictability from improved high-resolution precipitable water vapor initial data, which can be obtained from new high-resolution all-weather microwave sensors.

InSAR meteorology atmospheric predictability water vapor precipitation patterns data assimilation Sentinel-1
2019 Articolo in rivista metadata only access

Passive Bistatic Ground-Based Synthetic Aperture Radar: Concept, System, and Experiment Results

Feng Weike ; Friedt JeanMichel ; Nico Giovanni ; Wang Suyun ; Martin Gilles ; Sato Motoyuki

A passive bistatic ground-based synthetic aperture radar (PB-GB-SAR) system without a dedicated transmitter has been developed by using commercial-off-the-shelf (COTS) hardware for local-area high-resolution imaging and displacement measurement purposes. Different from the frequency-modulated or frequency-stepped continuous wave signal commonly used by GB-SAR, the continuous digital TV signal broadcast by a geostationary satellite has been adopted by PB-GB-SAR. In order to increase the coherence between the reference and surveillance channels, frequency and phase synchronization of multiple low noise blocks (LNBs) has been conducted. Then, the back-projection algorithm (BPA) and the range migration algorithm (RMA) have been modified for PB-GB-SAR to get the focused SAR image. Field experiments have been carried out to validate the designed PB-GB-SAR system and the proposed methods. It has been found that different targets within 100 m (like the fence, light pole, tree, and car) can be imaged by the PB-GB-SAR system. With a metallic plate moved on a positioner, it has been observed that the displacement of the target can be estimated by PB-GB-SAR with submillimeter accuracy.

ground-based synthetic aperture radar (GB-SAR) passive bistatic radar (PBR) satellite digital TV signa synthetic aperture radar (SAR) imaging displacement estimation
2019 Articolo in rivista metadata only access

Neural Network Approach to Forecast Hourly Intense Rainfall Using GNSS Precipitable Water Vapor and Meteorological Sensors

Benevides Pedro ; Catalao Joao ; Nico Giovanni

This work presents a methodology for the short-term forecast of intense rainfall based on a neural network and the integration of Global Navigation and Positioning System (GNSS) and meteorological data. Precipitable water vapor (PWV) derived from GNSS is combined with surface pressure, surface temperature and relative humidity obtained continuously from a ground-based meteorological station. Five years of GNSS data from one station in Lisbon, Portugal, are processed. Data for precipitation forecast are also collected from the meteorological station. Spaceborne Spinning Enhanced Visible and Infrared Imager (SEVIRI) data of cloud top measurements are also gathered, providing collocated information on an hourly basis. In previous studies it was found that the time-varying PWV is correlated with rainfall and can be used to detected heavy rain. However, a significant number of false positives were found, meaning that the evolution of PWV does not contain enough information to infer future rain. In this work, a nonlinear autoregressive exogenous neural network model (NARX) is used to process the GNSS and meteorological data to forecast the hourly precipitation. The proposed methodology improves the detection of intense rainfall events and reduces the number of false positives, with a good classification score varying from 63% up to 72% and a false positive rate of 36% down to 21%, for the tested years in the dataset. A score of 64% for intense rain events classification with 22% false positive rate is obtained for the most recent years. The method also achieves an almost 100% hit rate for the rain vs no rain detection, with close to no false alarms.

global navigation satellite system (GNSS) precipitable water vapor (PWV) precipitation meteorological sensors spinning enhanced visible and infrared imager (SEVIRI) neural network forecast
2019 Contributo in Atti di convegno metadata only access

Beyond Fact-Checking: Network Analysis Tools for Monitoring Disinformation in Social Media

Guarino ; Stefano ; Trino ; Noemi ; Chessa ; Alessandro ; Riotta ; Gianni

Operated by the H2020 SOMA Project, the recently established Social Observatory for Disinformation and Social Media Analysis supports researchers, journalists and fact-checkers in their quest for quality information. At the core of the Observatory lies the DisInfoNet Toolbox, designed to help a wide spectrum of users understand the dynamics of (fake) news dissemination in social networks. DisInfoNet combines text mining and classification with graph analysis and visualization to offer a comprehensive and user-friendly suite. To demonstrate the potential of our Toolbox, we consider a Twitter dataset of more than 1.3M tweets focused on the Italian 2016 constitutional referendum and use DisInfoNet to: (i) track relevant news stories and reconstruct their prevalence over time and space; (ii) detect central debating communities and capture their distinctive polarization/narrative; (iii) identify influencers both globally and in specific "disinformation networks".

Social network analysis Disinformation Classification