Numerical study of the Kadomtsev\u2013Petviashvili equation and dispersive shock waves

A detailed numerical study of the long time behaviour of dispersive shock waves in solutions to the Kadomtsev\u2013Petviashvili (KP) I equation is presented. It is shown that modulated lump solutions emerge from the dispersive shock waves. For the description of dispersive shock waves, Whitham modulation equations for KP are obtained. It is shown that the modulation equations near the soliton line are hyperbolic for the KPII equation while they are elliptic for the KPI equation leading to a focusing effect and the formation of lumps. Such a behaviour is similar to the appearance of breathers for the focusing nonlinear Schr\uf6dinger equation in the semiclassical limit

Regulation by anti-inflammatory cytokines (IL-4, IL-10, IL-13, TGFβ)of interleukin-8 production by LPS- and/ or TNFα-activated human polymorphonuclear cells

The capacity to down-regulate the production of IL-8 by LPS-activated human polymorphonuclear cells (PMN) has been demonstrated for IL-4, IL-10, and TGFβ. We compared their relative capacities and further extended this property to IL-13. We report a great heterogeneity among individuals related to the responsiveness of PMN to the IL-4 and IL-13 inhibitory effects while their response to the IL-10 effect was homogenous. The inhibitory activities were observed at the transcriptional level. IL-8 induction by TNFα was, unlike its induction by LPS, resistant to the inhibitory effects of IL-10, IL-4, IL-13 and TGFβ. Furthermore, IL-10 and IL-4 inhibitory activity were less effective when TNFα was acting synergistically with LPS to induce IL-8 production by PMN. LPS-induced cell-associated IL-8, detected in the PMN cultures, could be marginally inhibited by IL-4 and IL-10. Altogether, our data demonstrate that IL-13 is able to inhibit LPS-induced IL-8 production by human PMN, although IL-10 remains the most active anti-inflammatory cytokine. Despite the capacity of IL-4, IL-10, and IL-13 to limit the production of TNFα-induced IL-8 in a whole blood assay, none was able to inhibit this production when studying isolated human polymorphonuclear cells

A spectral element reduced basis method in parametric CFD

We consider the Navier-Stokes equations in a channel with varying Reynolds numbers. The model is discretized with high-order spectral element ansatz functions, resulting in 14,259 degrees of freedom. The steady-state snapshot solutions define a reduced order space, which allows to accurately evaluate the steady-state solutions for varying Reynolds number with a reduced order model within a fixed-point iteration. In particular, we compare different aspects of implementing the reduced order model with respect to the use of a spectral element discretization. It is shown, how a multilevel static condensation (Karniadakis and Sherwin, Spectral/hp element methods for computational fluid dynamics, 2nd edn. Oxford University Press, Oxford, 2005) in the pressure and velocity boundary degrees of freedom can be combined with a reduced order modelling approach to enhance computational times in parametric many-query scenarios

MosChito rafts as effective and eco-friendly tool for the delivery of a Bacillus thuringiensis-based insecticide to Aedes albopictus larvae

Adult mosquito females, through their bites, are responsible for the transmission of different zoonotic pathogens. Although adult control represents a pillar for the prevention of disease spread, larval control is also crucial. Herein we characterized the effectiveness of a suitable tool, named "MosChito raft", for the aquatic delivery of a Bacillus thuringiensis var. israelensis (Bti) formulate, a bioinsecticide active by ingestion against mosquito larvae. MosChito raft is a floating tool composed by chitosan cross-linked with genipin in which a Bti-based formulate and an attractant have been included. MosChito rafts (i) resulted attractive for the larvae of the Asian tiger mosquito Aedes albopictus, (ii) induced larval mortality within a few hours of exposure and, more importantly, (iii) protected the Bti-based formulate, whose insecticidal activity was maintained for more than one month in comparison to the few days residual activity of the commercial product. The delivery method was effective in both laboratory and semi-field conditions, demonstrating that MosChito rafts may represent an original, eco-based and user-friendly solution for larval control in domestic and peri-domestic aquatic habitats such as saucers and artificial containers in residential or urban environments

Different regulation of TNF alpha and IL-1ra synthesis in LPS-tolerant human monocytes

Contains fulltext : 4894.pdf (publisher's version ) (Open Access

Analysis of NTP DRDoS attacks’ performance effects and mitigation techniques

Denial of Service (DoS) attacks are a type of interruption (malicious and/or unintended) that restrict or completely deny services meant for legitimate users. One of the most relevant DoS attacks is Distributed Denial of Service (DDoS) attack which is a variant of DoS, but on a larger scale using previously compromised, malware infected computers known as “bots” or “zombies”. DDoS attack occurs by generating large amounts of traffic towards an intended victim. This paper focuses on analyzing a variant of DDoS attacks known as Network Time Protocol (NTP) Distributed Reflective Denial of Service (DRDoS) attack. The impact of the attack will be measured in the utilization of processor, memory, network and ping of most relevant devices. Further focus is on the host and network based layered “defense indepth” of NTP DRDoS attack mitigation techniques

Artificial Intelligence techniques in design optimization of variable stiffness cylindrical shells

The main driver of aerospace structures design is the increase in performances of currently in use components. The behavior of structures is investigated by means of highly accurate finite elements (FE) analysis. The problem related to this kind of simulations is the high computational time required to obtain the structural response associated with nonlinear phenomena. This aspect is particularly significant during the preliminary phase, especially when the analysis involves an optimization procedure. One strategy to overcome this problem is the introduction of artificial intelligence techniques in the design phase. This work proposes an optimization framework based on the approximation of the structural behavior through an artificial neural network (ANN). The net is exploited during the optimization, performed with a particle swarm optimizer, in order to reduce the computational effort. FE analysis are used to train the ANN and to validate the results. The methodology is applied to the optimization of the fibers shape of variable stiffness cylindrical shells, with the goal of maximize the critical load taking into account also manufacturing constraints. The higher accuracy offered by ANN with respect to other global approximation techniques and the time saving, resulting from the developed methodology, are both highlighted.Aerospace Structures & Computational Mechanic