Trust and distrust in contradictory information transmission

We analyse the problem of contradictory information distribution in networks of agents with positive and negative trust. The networks of interest are built by ranked agents with different epistemic attitudes. In this context, positive trust is a property of the communication between agents required when message passing is executed bottom-up in the hierarchy, or as a result of a sceptic agent checking information. These two situations are associated with a confirmation procedure that has an epistemic cost. Negative trust results from refusing verification, either of contradictory information or because of a lazy attitude. We offer first a natural deduction system called SecureNDsim to model these interactions and consider some meta-theoretical properties of its derivations. We then implement it in a NetLogo simulation to test experimentally its formal properties. Our analysis concerns in particular: conditions for consensus-reaching transmissions; epistemic costs induced by confirmation and rejection operations; the influence of ranking of the initially labelled nodes on consensus and costs; complexity results

A novel framework for seismic risk assessment of structures

Seismic risk assessment of new and existing structures has a long history, which is based on the development of specific methods for seismic hazard and vulnerability analyses. Performance-based earthquake engineering is the natural evolution and integration of all these aspects that is nowadays implemented in several precodes. However, some critical aspects are not yet completely clarified. As a matter of fact, the vulnerability analysis suffers the so-called record-to-record variability, which is usually controlled through different parameters used as seismic intensity measures (IMs), whose significance is still under discussion. Moreover, this variability represents an additional source of uncertainty, which is added to the dispersion derived from the ground motion prediction equation (GMPE), leading to an overconservatism. For these reasons, the present paper aims to propose a novel framework for the seismic risk assessment of structures, which is found on the idea to control the response variability in evaluating seismic hazard curves without taking into account the randomness (ε) of the GMPE, which instead is transferred to fragility curves. These latter are built by using groups of accelerograms, whose median and 84% fractile spectra fit well, for different return periods, the uniform hazard spectra for ε= 0 and 1, respectively. For this purpose, a new search algorithm for selecting natural records is formulated. The proposed method offers considerable advantages as it is no longer necessary to refer to a specific IM, and allows to select pairs of spectrum-compatible natural records, which is enable to solve the problem of the seismic assessment of three-dimensional structures. The procedure is then applied to assess seismic risk of a typical reinforced concrete frame, whose results demonstrate the robustness of the method and the practical independence from the record set used

Refined and simplified numerical models of an isolated old highway bridge for PsD testing

RETRO’ project aims at studying the seismic behaviour of existing reinforced concrete (RC) bridges and the effectiveness of retrofitting systems employing the seismic isolation of the deck of the viaduct. The research program focuses on a typical non-compliant bridge system, which designed for gravity loads only. The sample structure is Rio Torto bridge system, which is located in a region with medium seismic hazard in Italy. The seismic vulnerability of the as-built framed pier bridge is first assessed. A typical seismic isolation system, employing slide spherical bearings, is then designed as a passive control retrofitting measure. The present chapter discusses the non-linear response of the Rio-Torto viaduct in “as-built” and “isolated” configurations. The seismic performance assessment is carried out by utilizing refined non-linear structural models implemented in an ad-vanced and reliable computer platform. The earthquake behaviour of refined mod-els used for the sample structure accounts for the non-linear phenomena of the vi-aduct, e.g. strain penetration of plain bars, shear deformation of transverse beams, flexural deformations in columns and beams. The finite element models are cali-brated on the basis of experimental tests results. The assessment of the seismic re-sponse system is investigated in terms of local and global response parameters. In addition, the effectiveness of the isolation systems used as a retrofitting system is also investigated numerically. The outcomes of the comprehensive nonlinear anal-yses are used to simulate the seismic response of the viaduct in the as-built and isolated configurations for the Pseudo-dynamic testing, which is illustrated in a companion chapter

Variants at the 3p21 locus influence susceptibility and phenotype both in adults and early-onset patients with inflammatory bowel disease

Background: To date, a number of high-profile studies have yielded over 50 inflammatory bowel disease (IBD) disease genes/ loci. The polymorphisms rs9858542 (BSN) and rs3197999 (MST1), on 3p21 locus, have been found associated with susceptibility to IBD. We aimed to replicate these associations in adult and early-onset cohorts of IBD Italian patients, by analyzing also potential gene–gene interactions with variants in NOD2/CARD15, IL23R, ATG16L1, and IRGM genes, and investigating genotype– phenotype correlation. Methods: In all, 1808 patients with IBD, 855 with Crohn’s disease (CD) and 953 with ulcerative colitis (UC), including 539 patients with their initial diagnosis <19 years of age, and 651 controls were analyzed for SNPs rs9858542 and rs3197999. Results: BSN and MST1 were significantly associated with either CD (Prs9858542 2.5 10 7; Prs3197999 3.9 10 7), and UC (Prs9858542 ¼ 3.1 10 4; Prs3197999 ¼ 8 10 4). Prevalence of these variants was significantly increased in both adult and earlyonset IBD patients. After stepwise logistic regression, the 2 variants were associated in adult UC with distal colitis (Prs9858542 ¼ 0.013, odds ratio [OR] ¼ 2.04, 95% confidence interval [CI] ¼ 1.16–3.59; Prs3197999 ¼ 0.018, OR 1.9, 95% CI 1.2–3.3), while the rs3197999 variant was inversely associated with occurrence of extraintestinal manifestations in adult CD(P ¼ 0.017, OR 0.6, 95% CI 0.4–0.9). Conclusions: We confirmed the association of BSN and MST1 with IBD susceptibility, either in the adult or the early-onset cohorts. These variants appeared to influence either the distal location of the disease in the UC cohort and extraintestinal manifestations in CD patients