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The aim of this study was to measure implant stability quotient (ISQ) values in grafted sites during 5 years of follow-up. Sixteen patients received a total of 36 implants inserted in sites treated with autologous bone (group A) or porcine bone in addition to autologous bone (group B). In both groups, resonance frequency analysis (RFA) values increased during the observation period. At 2 months, statistical analysis showed significantly lower ISQ values for group B than for group A (P = .0134) and significantly higher ISQ values in the mandible than in the maxilla (P = .0251). RFA measurements suggested stable long-term results for implants inserted in both groups. [ABSTRACT FROM AUTHOR]

The stability of embankment dams without an impermeable core depends on the characteristics of the face slab that prevents internal erosion, piping and eventual collapse of the structure. Under a Mediterranean climate, the impermeable asphaltic face slab is subjected to high solar radiation and consequent temperature changes, which can generate the creation of cracks and joints. The Medau Zirimilis Dam, located in the Casteddu River (Sardinia), is an embankment dam that has undergone seepage and continuous repairs in its asphalt face slab. These reparations have been conducted because of the occurrence of cracks and relative movement of different segments of the slab. To evaluate if seepage endangers the integrity of the dam, GPR was used, with different antennas (100, 250 and 500 MHz), along its crest and upstream and downstream faces, and the data were integrated with infrared thermographic images. Although geophysical data do not show structural changes affecting the main dam structure, deformation structures at shallow levels and in particular in the upstream face and along the crest of the dam have been identified. Such deformation affects the road atop the crest, the face slab and underlying levels, resulting in landslides that include material from several meters below the surface. The analysis permitted the identification of the origin of surficial cracks and their effects on the face slab. These sectors, independent of current movement, define the most unstable areas against water level changes that can affect the dam integrity. GPR analysis at the embankments usually has the handicap of high clay content that precludes electromagnetic wave penetration; however, in this case, the obtained resolution and extent of penetration using the different antennas was sufficient, due to the absence of an inner waterproof unit, and permitted the evaluation of the inner structure of the dam and the application of GPR for construction quality surveillance, internal structural characterization and dam monitoring. [ABSTRACT FROM AUTHOR]

This paper presents some of the geotechnical studies carried out for the seismic design of the one-span suspension bridge across the Messina Strait, that is to connect Sicily with mainland Italy. These studies included advanced geotechnical characterisation, through in situ and laboratory tests, estimate of site stability involving both liquefaction analysis and submerged slope stability, evaluation of soil-foundation stiffness for spectral analysis of the superstructure, 3D FE static calculations, evaluation of anchor block performance under seismic conditions, and full dynamic analyses of the soil-structure interaction. The paper summarises the main results obtained from the geotechnical characterisation of the foundation soils, reports the approach adopted for evaluating the seismic performance of the anchor blocks through a modified Newmark-type calculation, and presents the study of the soil-structure interaction carried out through a series of two-dimensional, plane strain numerical analyses. In these analyses, in addition to the embedded foundation elements, the models included a simplified structural description of the bridge towers specifically designed to reproduce their first vibrations modes, that were deemed to have the most significant influence on the system's dynamic response. The illustration is limited to the foundation systems of the bridge located on the Sicily shore. [ABSTRACT FROM AUTHOR]

Tree stability assessments are an indispensable tool for preserving the safety of people and property. National legislation identifies the tree custodians as those responsible for monitoring the risk factors with regard to civil and criminal liability for damage to persons or property. Currently evaluations to assess tree stability are usually made by means of visual methods and they do not always allow for an evaluation of the true health the plant. The controlled pulling test is considered to be particularly useful to evaluate the tendency of root-plate windthrow caused by thrust exerted by meteorological events such as wind and snow. This type of instrumental analysis is not yet widespread in Italy and it is sometimes applied improperly. As a result, this preliminary study focuses on these issues in order to develop a methodology with particular reference to the definition of the fundamental variables, as well investigating the possibility of its application to Mediterranean species. [ABSTRACT FROM AUTHOR]

The paper deals with the seismic stability assessment of two existing earth dams in Italy using a fully coupled effective stress nonlinear approach implemented in a finite-element (FE) code. The mechanical behavior of the involved clayey and granular soils is described through advanced elastoplastic constitutive models, calibrated on laboratory and in situ test results. Before the application of the seismic motions, appropriate FE static analyses are performed in both cases to define the initial stress state and the internal variables of the material models. The stability of both dams during dynamic loading is proved by inspection of the cumulated horizontal and vertical displacement time histories of the monitored solid nodes, which become constant immediately after the end of the seismic actions. Moreover, the computed crest settlements induced by the earthquakes are considerably smaller than the service freeboard of the dams. Because the applied seismic actions are characterized by high return periods, the presented results are indicative of a satisfactory dynamic performance of the two embankments during extreme dynamic loading conditions. [ABSTRACT FROM AUTHOR]

Abstract: Current approaches to rocky slope stability analysis require knowledge of the geometrical–structural setting, as well as the physical–mechanical properties of the intact material and its discontinuities. The physical–mechanical properties are derived from in situ and laboratory tests, whereas the geometrical characteristics come from field attitude measurements. Frequently, the inaccessibility of walls does not allow direct measurement of discontinuity surfaces by traditional geological methods. In such cases, data can only be obtained by statistical methods. Although this approach is significant and provides spatial meaning, it is ineffective for deterministic analysis. This paper provides a solution to this problem by applying digital terrestrial photogrammetric techniques employing a reamed bar, an aerostatic balloon and a helicopter. Results demonstrate that the accuracy and the quantity of geometrical and engineering–geological data coming from the photogrammetric survey, allow for numerical simulation of the relationship between rock elements as a function of their physical–mechanical properties and load conditions. The 3DEC code was chosen among the different methods available to model the discontinuous media through distinct elements. The proposed methodology was applied to a quarry located in the Carrara Marble District (the Apuan Alps, Italy), the largest and most exploited mining region in Europe. The economic value of the area required a detailed study of the presence of instability phenomena so that marble extraction could continue in safe conditions. [Copyright &y& Elsevier]

The Petacciato landslide that occurred between 1906 and 1966 along a stretch of the Adriatic coast (Italy) and the Trevoux landslide that appeared in 1983 in France are analysed using Hill's material sufficient stability condition, which is based on the sign of the second-order work. Local and global sufficient stability criteria allow detecting and describing the instability phenomena, respectively, at the material point level and for the whole domain. By considering the non-associated Plasol elasto-plastic constitutive model and the second-order work criterion, it is shown that unstable stress-strain states can be reached in plane strain conditions, strictly inside the plastic limit criterion. The two landslides that occurred in Petacciato and Trevoux are then analysed by modelling unsaturated hydro-mechanical coupling. The analysis is carried out using the Lagamine finite element code. This original approach to slope stability analysis makes it possible successfully to exhibit the landslide mechanism observed on these slopes after a long rainy period: this could not be described with the classical methods. [ABSTRACT FROM AUTHOR]

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This paper presents an innovative approach to the study of regional economic dynamics within a nonlinear continuous-time econometric framework—a generalized specification of the Lotka–Volterra system of equations. This specification, which accounts for interdependent behavior of three industrial sectors and spillover effects of activities in neighboring regions, is employed in an analysis of five Italian regions between 1980 and 2003. For these regions, we report estimation results, characterize the varying systems dynamics, analyze the models’ local and global stability properties, and determine via sensitivity analyses which structural features appear to exert the greatest influence on these properties. [ABSTRACT FROM AUTHOR]

Five published indirect methods to estimate benthic secondary production of intertidal mudflats and a new proposed formulation based on quarter-power allometric scaling and the “Universal Temperature Dependence” of biological processes (UTD) were compared. For this purpose, a dataset consisting of an annual series of samples, taken from the Lagoon of Venice from March 1996 to March 1997, at sites characterised by different seagrass coverage was used. All methods resulted in that biomass and secondary production decreased progressively when moving from the seagrass meadow toward areas of unvegetated substrate, suggesting an influence of the available marine phanerogams on the neighbouring sites. The equation proposed in this paper gives results comparable with those obtained using empirical regression models from literature. The main conclusion from this study is that general equations proposed by the “metabolic theory of ecology” can be applied for indirect estimations of secondary production of benthic communities. [ABSTRACT FROM AUTHOR]

In this paper, species diversity of demersal fish communities was analysed over an area covering about 45,000 km2 of the Italian side of the Strait of Sicily (central Mediterranean). Fish abundance data come from a 10-year series (1994–2003) of experimental bottom trawl surveys carried out within the framework of the international program MEDITS. A simple GIS-based method was proposed to identify areas supporting high or low values of diversity and evaluate their temporal stability. A well-defined spatio-temporal pattern in diversity emerged from the analysis, with some areas of great ecological relevance being identified. Importantly, the greatest diversity within the fish communities was consistently seen at the offshore bank on the western part of the south Sicilian shelf (Adventure Bank). The site also supports high total biomass of demersal resources and shows the presence of species of great concern to fisheries. Results suggest that Adventure Bank represents a priority site for investigating the possibility of innovative management of marine ecosystems and demersal fisheries in offshore zones. [ABSTRACT FROM AUTHOR]

Abstract: Radon concentration measurements in atmosphere were taken in years from 1997 to 1999 in Milan and at pre-alpine sites located north of Lombardy. In this paper the results of measuring campaigns and a comparison of radon levels observed in the hilly area north of the town and on the pre-Alps are reported. The general criteria of the measurements and the interpretative models of radon concentration are presented. The Lake Maggiore area shows evidence of a great nocturnal stability and frequent formation of Nocturnal Stable Layer. The peculiar findings in the high altitude stations confirm the use of radon as an indicator of atmospheric dispersion of pollutants in an area with complex orography. The afternoon minimum values are concordant for the different stations: this implies a remixing in afternoon hours over the whole area investigated. [Copyright &y& Elsevier]

This is an applied study about the stability of collective decision-making in fiscal matters and the features of individual preferences which are sufficient to reach a social ordering. It is based on data about citizens' preferences collected through a budget game played by a sample of voters in Turin, a large Italian city. By simulating a series of individual choices, a social ordering of the municipal budget items is arrived at. The role played by restricted (i.e., single-peaked, single-caved etc.) preferences to avoid cycles in choice simulations is then assessed. [ABSTRACT FROM AUTHOR]