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2018 Articolo in rivista metadata only access

The epigenetics of inflammaging: The contribution of age-related heterochromatin loss and locus-specific remodelling and the modulation by environmental stimuli

Nardini C ; Moreau JF ; Gensous N ; Ravaioli F ; Garagnani P ; Bacalini MG

A growing amount of evidences indicates that inflammaging - the chronic, low grade inflammation state characteristic of the elderly - is the result of genetic as well as environmental or stochastic factors. Some of these, such as the accumulation of senescent cells that are persistent during aging or accompany its progression, seem to be sufficient to initiate the aging process and to fuel it. Others, like exposure to environmental compounds or infections, are temporary and resolve within a (relatively) short time. In both cases, however, a cellular memory of the event can be established by means of epigenetic modulation of the genome. In this review we will specifically discuss the relationship between epigenetics and inflammaging. In particular, we will show how age-associated epigenetic modifications concerned with heterochromatin loss and gene-specific remodelling, can promote inflammaging. Furthermore, we will recall how the exposure to specific nutritional, environmental and microbial stimuli can affect the rate of inflammaging through epigenetic mechanisms, touching also on the recent insight given by the concept of trained immunity.

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2018 Articolo in rivista metadata only access

The Generalized Schur Algorithm and Some Applications

The generalized Schur algorithm is a powerful tool allowing to compute classical decompositions of matrices, such as the QR and LU factorizations. When applied to matrices with particular structures, the generalized Schur algorithm computes these factorizations with a complexity of one order of magnitude less than that of classical algorithms based on Householder or elementary transformations. In this manuscript, we describe the main features of the generalized Schur algorithm. We show that it helps to prove some theoretical properties of the R factor of the QR factorization of some structured matrices, such as symmetric positive definite Toeplitz and Sylvester matrices, that can hardly be proven using classical linear algebra tools. Moreover, we propose a fast implementation of the generalized Schur algorithm for computing the rank of Sylvester matrices, arising in a number of applications. Finally, we propose a generalized Schur based algorithm for computing the null-space of polynomial matrices.

generalized Schur algorithm; null-space; displacement rank; structured matrices
2018 Articolo in rivista metadata only access

Numerical approximation of nonhomogeneous boundary conditions on networks for a hyperbolic system of chemotaxis modeling the Physarum dynamics

Bretti ; Gabriella Natalini ; Roberto

Many studies have shown that Physarum polycephalum slime mold is able to find the shortest path in a maze. In this paper we study this behavior in a network, using a hyperbolic model of chemotaxis. Suitable transmission and boundary conditions at each node are considered to mimic the behavior of such an organism in the feeding process. Several numerical tests are presented for special network geometries to show the qualitative agreement between our model and the observed behavior of the mold.

Chemotax networks finite difference schemes shortest path problem Physarum polycephalum hyperbolic equations
2018 Articolo in rivista metadata only access

Second-order entropy satisfying BGK-FVS schemes for incompressible Navier-Stokes equations

François Bouchut ; Yann Jobic ; Roberto Natalini ; René Occelli ; Vincent Pavan

Kinetic BGK numerical schemes for the approximation of incompressible Navier-Stokes equations are derived via classical discrete velocity vector BGK approximations, but applied to an inviscid compressible gas dynamics system with small Mach number parameter, according to the approach of Carfora and Natalini (2008). As the Mach number, the grid size and the timestep tend to zero, the low Mach number limit and the time-space convergence of the scheme are achieved simultaneously, and the numerical viscosity tends to the physical viscosity of the Navier-Stokes system. The method is analyzed and formulated as an explicit finite volume/difference flux vector splitting (FVS) scheme over a Cartesian mesh. It is close in spirit to lattice Boltzmann schemes, but it has several advantages. The first is that the scheme is expressed only in terms of momentum and mass compressible variables. It is therefore very easy to implement, and several types of boundary conditions are straightforward to apply. The second advantage is that the scheme satisfies a discrete entropy inequality, under a CFL condition of parabolic type and a subcharacteristic stability condition involving a cell Reynolds number that ensures that diffusion dominates advection at the level of the grid size. This ensures the robustness of the method, with explicit uniform bounds on the approximate solution. Moreover the scheme is proved to be second-order accurate in space if the parameters are well chosen, this is the case in particular for the Lax-Friedrichs scheme with Mach number proportional to the grid size. The scheme falls then into the class of artificial compressibility methods, the novelty being its exceptionally good theoretical properties. We show the efficiency of the method in terms of accuracy and robustness on a variety of classical two-dimensional benchmark tests. The method is finally applied in three dimensions to compute the permeability of a porous medium defined by a complex idealized Kelvin-like cell. Relations between our scheme and compressible low Mach number schemes are discussed.

incompressible Navier-Stokes equations vector BGK schemes flux vector splitting low Mach number limit discrete entropy inequality cell Reynolds number lattice Boltzmann schemes
2018 Contributo in volume (Capitolo o Saggio) metadata only access

Mesoscale Simulations of Janus Particles and Deformable Capsules in Flow

Othmane Aouane ; Qingguang Xie ; Andrea Scagliarini ; Jens Harting

Chapter in book "High Performance Computing in Science and Engineering ' 17"

High Performance Computing Lattice Boltzmann Method Complex Fluids Suspensions
2018 Articolo in rivista metadata only access

A "pay-how-you-drive" car insurance approach through cluster analysis

Carfora MF ; Martinelli F ; Mercaldo F ; Nardone V ; Orlando A ; Santone A ; Vaglini G

As discussed in the recent literature, several innovative car insurance concepts are proposed in order to gain advantages both for insurance companies and for drivers. In this context, the "pay-how-you-drive" paradigm is emerging, but it is not thoroughly discussed and much less implemented. In this paper, we propose an approach in order to identify the driver behavior exploring the usage of unsupervised machine learning techniques. A real-world case study is performed to evaluate the effectiveness of the proposed solution. Furthermore, we discuss how the proposed model can be adopted as risk indicator for car insurance companies.

Insurance; Risk analysis; OBD; CAN; Cluster analysis; Machine learning
2018 Contributo in Atti di convegno metadata only access

Cluster Analysis for Driver Aggressiveness Identification

F Martinelli ; F Mercaldo ; V Nardone ; A Orlando ; A Santone

In the last years, several safety automotive concepts have been proposed, for instance the cruise control and the automatic brakes systems. The proposed systems are able to take the control of the vehicle when a dangerous situation is detected. Less effort was produced in driver aggressiveness in order to mitigate the dangerous situation. In this paper we propose an approach in order to identify the driver aggressiveness exploring the usage of unsupervised machine learning techniques. A real world case study is performed to evaluate the effectiveness of the proposed method.

automotive machine learning
2018 Contributo in Atti di convegno metadata only access

Context-Awareness Mobile Devices for Traffic Incident Prevention

F Martinelli ; F Mercaldo ; V Nardone ; A Orlando ; A Santone

Several techniques have been developed in last years by automotive industry in order to protect drivers and car passengers. These methods, for instance the automatic brake systems and the cruise control, are able to intervene when there is a dangerous situation. With the aim to minimize these risks, in this paper we propose a method able to suggest to the driver the driving style to adopt in order to avoid dangerous situations. Our method is basically a two-level fuzzy systems: the first one is related to the driver under analysis, while the second one is a centralized server with the responsibility to send suggestions to drivers in order to prevent traffic incidents. We carried out a preliminary evaluation to demonstrate the effectiveness of the proposed method: we obtain of percentage variation ranging from 85.48% to 88.99% in the number of traffic incidents between the scenarios we considered using the proposed method and the scenario without the proposed method applied.

automotive fuzzy logic
2018 Contributo in Atti di convegno metadata only access

Cyber risk management: a new challenge for actuarial mathematics

A specific kind of insurance that is emerging within the domain of cyber-systems is that of cyber-insurance. Cyber-insurance is the transfer of financial risk associated with network and computer incidents to a third party. Insurance companies are increasingly offering such policies, in particular in the USA, but also in Europe. The emerging trends in cyber insurance raise a number of unique challenges and force actuaries to reconsider how to think about underwriting, pricing and aggregation risk. Aim of this contribution is to offer a review of the recent literature on cyber risk management in the actuarial field. Moreover, basing on the most significant results in IT domain, we outline possible synergies between the two lines of research.

cyber insurance Cyber risk Risk management
2018 Abstract in Atti di convegno metadata only access

Optimal spatio-temporal control of invasive plant in protected areas

We develop a modelling approach for the optimal spatiotemporal control of invasive species in natural protected areas of high conservation value. The proposed approach, based on diusion equations, is spatially explicit, and includes a functional response (Holling type II) which models the control rate as a function of the invasive species density. We apply a budget constraint to the control program and search for the optimal eort allocation for the minimization of the invasive species density. Both the initial density map and the land cover map used to estimate the habitat suitability to the species diusion, have been generated by using very high resolution satellite images and validated by means of ground truth data. The approach has been applied to the Alta Murgia National Park, one of the study site of the on-going H2020 project ECOPOTENTIAL: Improving Future Ecosystem Benets Through Earth Observations' (http://www.ecopotential-project.eu) which has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 641762. All the ground data regarding Ailanthus altissima (Mill.) Swingle presence and distribution are from the EU LIFE Alta Murgia Project (LIFE12 BIO/IT/000213) titled Eradication of the invasive exotic plant species Ailanthus altissima from the Alta Murgia National Park funded by the LIFE+ nancial instrument of the European Commission.

optimal control invasive species protected areas
2018 Articolo in rivista metadata only access

Stability of Numerical Solutions for Abel-Volterra Integral Equations of the Second Kind

Izzo G ; Messina E ; Vecchio A

We analyze the stability of convolution quadrature methods for weakly singular Volterra integral equations with respect to a linear test equation. We prove that the asymptotic behavior of the numerical solution replicates the one of the continuous problem under some restriction on the stepsize. Numerical examples illustrate the theoretical results.

Weakly singular integral equations Numerical stability Convolution quadrature
2018 Articolo in rivista metadata only access

Effect of perturbation in the numerical solution of fractional differential equations

R Garrappa ; E Messina ; AVecchio

The equations describing engineering and real-life models are usually derived in an approximated way. Thus, in most cases it is necessary to deal with equations containing some kind of perturbation. In this paper we consider fractional dfferential equations and study the eects on the continuous and numerical solution, of perturbations on the given function, over long-time intervals. Some bounds on the global error are also determined.

Fractional differential equations Perturbations Product-integration Stability Volterra integral equations
2018 Articolo in rivista metadata only access

Coupled SPH-FV method with net vorticity and mass transfer

Chiron L ; Chiron L ; Marrone S ; Di Mascio A ; Le Touzé D

Recently, an algorithm for coupling a Finite Volume (FV) method, that discretize the Navier-Stokes equations on block structured Eulerian grids, with the weakly-compressible Lagrangian Smoothed Particle Hydrodynamics (SPH) was presented in [16]. The algorithm takes advantage of the SPH method to discretize flow regions close to free-surfaces and of the FV method to resolve the bulk flow and the wall regions. The continuity between the two solutions is guaranteed by overlapping zones. Here we extend the algorithm by adding the possibility to have: 1) net mass transfer between the SPH and FV sub-domains; 2) free-surface across the overlapping region. In this context, particle generation at common boundaries is required to prevent depletion or clustering of particles. This operation is not trivial, because consistency between the Lagrangian and Eulerian description of the flow must be retained to ensure mass conservation. We propose here a new coupling paradigm that extends the algorithm developed in [16] and renders it suitable to test cases where vorticity and free surface significantly pass from one domain to the other. On the SPH side, a novel technique for the creation/deletion of particle was developed. On the FV side, the information recovered from the SPH solver are exploited to improve free surface prediction in a fashion that resemble the Particle Level-Set algorithms. The combination of the two new features was tested and validated in a number of test cases where both vorticity and front evolution are important. Convergence and robustness of the algorithm are shown.

Coupling algorithms Domain decomposition Finite volume method Smoothed particle hydrodynamics
2018 Articolo in rivista metadata only access

Experimental and numerical investigation of propeller loads in off-design conditions

The understanding of the performance of a propeller in realistic operative conditions is nowadays a key issue for improving design techniques, guaranteeing safety and continuity of operation at sea, and reducing maintenance costs. In this paper, a summary of the recent research carried out at CNR-INSEAN devoted to the analysis of propeller loads in realistic operative scenarios, with particular emphasis on the in-plane loads, is presented. In particular, the experimental results carried out on a free running maneuvering model equipped with a novel force transducer are discussed and supported by CFD (Computational Fluid Dynamics) analysis and the use of a simplified propeller model, based on Blade Element Momentum Theory, with the aim of achieving a deeper understanding of the mechanisms that govern the functioning of the propeller in off-design. Moreover, the analysis includes the scaling factors that can be used to obtain a prediction from model measurements, the propeller radial force being the primary cause of failures of the shaft bearings. In particular, the analysis highlighted that cavitation at full scale can cause the increment of in-plane loads by about 20% with respect to a non-cavitating case, that that in-plane loads could be more sensitive to cavitation than thrust and torque, and that Reynolds number effect is negligible. For the analysis of cavitation, an alternative version of the BEMT solver, improved with cavitation linear theory, was developed.

Cavitation CFD maneuvering simulations Free running experiments Off-design Propeller models Propeller radial force Scale effects
2018 Articolo in rivista open access

A modular variable Orlicz inequality for the local maximal operator

In this note we prove a modular variable Orlicz inequality for the local maximal operator. This result generalizes several Orlicz and variable exponent modular inequalities that have appeared previously in the literature.

Musielak-Orlicz spaces local maximal operator variable exponents variable Lebesgue spaces modular inequality
2018 Abstract in Atti di convegno metadata only access

A MEG source reconstruction workflow

meg inverse problem python data analysis eeg connectivity
2018 Poster in Atti di convegno metadata only access

Visbrain: A multi-purpose GPU-accelerated open-source suite for brain data visualization

Etienne Combrisson ; Raphael Vallat ; Christian O'Reilly ; Annalisa Pascarella ; Annelise Saive ; Thomas Thiery ; David Meunier ; Dmitri Althukov ; Tarek Lajnef ; Perrine Ruby ; Aymeric Guillot ; Karim Jerbi

We present a Python open-source package called Visbrain that offers a coherent visualization suite for multi-modal brain data (intracranial and scalp EEG, MEG, structural and functional MRI). The current version of Visbrain is essentially articulated around four modules dedicated to 1) 3D visualization of functional and/or connectivity results (Brain), 2) polysomnographic data visualization and sleep analysis (Sleep, [1]), 3) data mining and basic plotting functions (Signal), 4) topographic representation (Topo). We also included functions for page layout and export of paper-ready high-quality figure. Those modules come with a modular and powerful graphical user interfaces built with PyQt. Each module has been developed in collaboration with neuroscientists and experts in the field and provides a comprehensive set of functionalities. Visbrain is developed on top of VisPy [2], a Python package providing high performance 2D and 3D visualization by leveraging the computational power of the graphic card. This package is available on Github and comes with an extensive documentation, examples and datasets (see http://visbrain.org).

python visualization data analysis meg eeg
2018 Abstract in Atti di convegno metadata only access

OPTIMAL CONTROL OF INVASIVE SPECIES

The containment of the invasive species is a widespread problem in the environmental management, with a significant economic impact. We analyze an optimal control model which aims to find the best temporal resource allocation strategy for the removal of an invasive species. We study the existence and uniqueness of the optimal solution when both initial and final conditions on the state variable are fixed. We derive and alternative optimality system in the state and control variables and we use the phase-space analysis to provide qualitative insights into the system dynamics and to analyze the behavior of the optimal solution. Finally, we find the expression of the optimal solution for the free terminal time problem. We apply these techniques to two case studies: the case of feral cats population in Australia, where we assume a logistic growth; the control of wild-boars populations in Italy, where we include an Allee effect in the population growth. This work has been carried out within the H2020 project 'ECOPOTENTIAL: Improving Future Ecosystem Benefits Through Earth Observations'. The project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No 641762. References [1] Baker, C. M., F. Diele, D. Lacitignola, C. Marangi, A. Martiradonna (2017). Optimal control of invasive species through a dynamical systems approach, Discrete and Continuous Dynamical System, under review. [2] Baker, C.M., M. Bode (2013). Spatial control of invasive species in conservation landscapes, Comput. Manag. Sci., 10, 331-351. [3] Lenhart, S., J.T. Workman (2007). Optimal control applied to biological models, Chapman & Hall/CRC, London.

invasive species optimal control phase space analysis
2018 Curatela di numero monografico in rivista metadata only access

12th and 13th International Meeting on Computational Intelligence Methods for Bioinformatics and Biostatistics (CIBB 2015/16)

Riccardo Rizzo ; Claudia Angelini ; Andrea Bracciali ; David Gilbert

This BMC special issue collects a selection of eleven revised and extended papers presented at, or originated from, the 2015 and 2016 editions of the international meeting on Computational Intelligence methods for Bioinformatics and Biostatistics, CIBB2015 and CIBB2016, respectively.

bioinformatics Biostatistics Omics data analysis
2018 Curatela di Atti di convegno metadata only access

Proceedings from the 12th International BBCC conference; BBCC2017

Selection of papers from BBCC2017

Bioinformatics Omics data analysis Data integration