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Abstract: The paper deals with the dynamic characterization and the evaluation of the seismic performances of historical masonry towers and bell-towers that are particularly vulnerable with respect to seismic actions. The main purpose of the study is to investigate how the seismic assessment of such historical constructions is influenced by the level of refinement of the adopted models and by the type of the performed analyses. The effectiveness of some provisions contained in the Italian guidelines for the seismic risk assessment and mitigation of cultural heritage for this kind of structures is also evaluated. The study is performed with reference to the medieval civic tower of Soncino (Cremona, Italy), that is representative of the considered class of masonry constructions. The dynamic characteristics and the mechanical properties of the masonry tower are evaluated through a dynamic identification with ambient vibration tests. Analytical models of the tower characterized by different refinement levels are calibrated on the results of the performed dynamic identification and used to carry out nonlinear static and dynamic analyses. The performed analyses evidence the very conventional nature of the behaviour factor q for this kind of structure. Moreover from the analyses it results that the q values suggested by the Italian codes overestimate the actual q values. The results obtained with the nonlinear dynamic analysis are in a good agreement with those obtained with the nonlinear static analysis. However the nonlinear dynamic analysis provides levels of displacement capacity lower than those resulting from the nonlinear static analysis and allows to consider the significant effect of the higher frequencies on some of the response parameters, as the base shear. The vulnerability of the tower is also assessed according to the Italian guidelines for the seismic risk assessment and mitigation of cultural heritage using the results of the performed nonlinear static analysis. [Copyright &y& Elsevier]

Abstract: The paper analyses the static behaviour and the seismic vulnerability of the Basilica of Santa Maria all’Impruneta near Florence (Italy). The static structural behaviour and the dynamic properties of the church have been evaluated using the finite element modelling technique, where the nonlinear behaviour of masonry has been taken into account by proper constitutive assumptions. A macro-modelling approach has been used based on the concepts of homogenisated material and smeared cracking and crushing constitutive law. Seismic vulnerability has been evaluated using a pushover method, and the results obtained with the nonlinear numerical model have been compared with the simplified schemes of limit analysis. The capacity of the church to withstand lateral loads is evaluated together with the expected demands resulting from seismic actions. The comparison of seismic demand vs. capacity confirms the susceptibility of this type of buildings to extensive damage and collapse, as frequently observed in similar buildings. The paper’s aim was to point out that advanced numerical analyses can offer significant information on the understanding of the actual structural behaviour of historic buildings. The methodology and the conclusions of this case study it is believed that are applicable to a wide variety of historic Basilica churches. [Copyright &y& Elsevier]

Objective: To investigate sperm mitochondrial integrity through analysis of mitochondrial membrane potential (Δψ) and to correlate the energy status with variations in sperm motility. Design: Experimental study. Setting: Seminology Laboratory, University of Rome, Italy. Patient(s): Two hundred thirteen semen samples from the same number of patients, divided into two groups on the basis of their motility: group A, 185 samples with linear motility and group B, 28 samples with nonlinear motility. Intervention(s): Evaluation of sperm motility. Main Outcome Measure(s): Sperm mitochondrial integrity evaluated with a fluorimetric method using the cationic lipophilic stain JC-1. Result(s): The mean FL2 (percentage of sperm with high and low ∆ψ) for group A was 46.19 ± 23.25 and for group B, it was 48.32 ± 24.43. There was no significant difference between the groups. There was a positive correlation between both FL2 and linear motility and FL2 and sperm vitality in group A; both correlations were statistically significant. In group B, there was a positive correlation between FL2 and nonlinear motility and FL2 and sperm vitality; again, both correlations were statistically significant. Conclusion(s): Our data reveal a positive correlation between total motility and Δψ, suggesting that sperm motility may be dependent on the functional integrity of the mitochondria. [ABSTRACT FROM AUTHOR]

The current Italian structural code (NTC2008) includes the results of recent studies on Italian seismic hazard. Seismic actions are referred to a continuous scale, thus enabling a higher level of accuracy of the intensity values with respect to the past seismic classification. Such a difference can determine remarkable effects on the current seismic deficit of the existing building stock designed only to vertical loads, thus on the amount of possible retrofitting interventions. In this paper, the Italian provincial capitals and the municipalities of Basilicata region are referred to for the significant differences between design seismic actions provided by the NTC2008 code and the past seismic classification (OPCM3274) and are discussed first. Moreover, by adopting both classifications, the performances of typical RC buildings designed only to vertical loads have been assessed. Results have been compared in terms of building number and volume, as well as people residing in the Basilicata region. [ABSTRACT FROM AUTHOR]

Abstract: In this paper we demonstrate that the seismic sequence of foreshocks culminating with the recent M w =6.3 main shock on April 6, 2009 in L''Aquila (Central Italy) evolved as a chaotic process. To do this, we apply a nonlinear retrospective prediction to this seismic sequence and look at the temporal behaviour of the error between predicted and actual occurrence of the main shock when gradually increasing parts of the sequence are considered. This is a generalisation of the typical nonlinear approach which is quite powerful to detect chaos in relatively short time series. The method of prediction is based on the Accelerated Strain Release (ASR) analysis in time and on the nonlinear forecasting approach in a reconstructed phase space. We find that i) the temporal decay of the prediction error is consistent with an exponential function with a time constant τ of about 10days and ii) at around 6days before the main shock, ASR analysis is quite powerful for anticipating the time of occurrence with an uncertainty of about a day. Due to its retrospective characteristics, the latter result could be affected by changes on some a-priori parameters used in the application of the ASR technique. However, we consider these findings, together with those obtained from the phase-space analysis, to be strong evidence that the studied sequence of foreshocks was produced by a physical process dominated by a significant chaotic component characterised by a K-entropy=1/τ of about 0.1day−1. This result could have important implications for the predictability of the possible main shock for those seismic sequences showing analogous nonlinear chaotic properties. [Copyright &y& Elsevier]

Abstract: In the southern part of Italy, along the National Road 163 (the Amalfi Coastal road), and particularly close to Positano, some stone formations are present with a cylindrical shape (pinnacles) due to the erosion of the rock and the presence of sub-vertical cracking planes in the rocky slope. The landscape beauty and the dangerousness of these pinnacles, more than 10m in height, leaning on the underlying road, requested a vulnerability study. The dynamic behavior of these natural solids is influenced by the notable mechanical inhomogeneity due to the nature of the rock, to the presence of diffused crack patterns and to the position along the slope. Some inspections have been performed to have a detailed survey of the pinnacles, using the Laser Scanner 3D technique and with the collaboration of geologist-mountain climbers; some rock specimens have also been taken to be analyzed and tested. The specific weight, the tensile (for bending) strength and the compressive strength, as well as the Young Modulus, considering various directions with respect to cracking planes, were analyzed during laboratory tests on the specimens sampled on site. Different structural modeling to analyze the seismic vulnerability of the pinnacles have been performed and compared: starting from simplified mechanical models of rigid blocks, passing through elastic analyses and finally to finite element (FEM) analyses. Numerical dynamic and static analyses, particularly, the modal dynamic analyses for the elastic continuum and the non-linear static analyses, considering both cracking and plasticity behavior of the rock have been performed. The analyses concerned the pinnacles both under the actual in-situ conditions and according to some strengthening interventions to evaluate the effectiveness and safety of the design. [Copyright &y& Elsevier]

The article reports on the events of the fourth "Nonlinear Physics: Theory and Experiment IV," conference held at Baia Verde, near Gallipoli, Italy, from June 22 to July 1, 2006. A brief history of the previous congresses on mathematical physics are given. The topics addressed at the conference by the researchers are overviewed.