Sensitivity to social exclusion in major depressive disorder (MDD) predicts therapeutic outcome after in-patient treatment

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Prediction Possibility in the Fractal Overlap Model of Earthquakes

The two-fractal overlap model of earthquake shows that the contact area distribution of two fractal surfaces follows power law decay in many cases and this agrees with the Guttenberg-Richter power law. Here, we attempt to predict the large events (earthquakes) in this model through the overlap time-series analysis. Taking only the Cantor sets, the overlap sizes (contact areas) are noted when one Cantor set moves over the other with uniform velocity. This gives a time series containing different overlap sizes. Our numerical study here shows that the cumulative overlap size grows almost linearly with time and when the overlapsizes are added up to a pre-assigned large event (earthquake) and then reset to `zero' level, the corresponding cumulative overlap sizes grows upto some discrete (quantised) levels. This observation should help to predict the possibility of `large events' in this (overlap) time series.Comment: 6 pages, 6 figures. To be published as proc. NATO conf. CMDS-10, Soresh, Israel, July 2003. Eds. D. J. Bergman & E. Inan, KLUWER PUB

Earthquake statistics and fractal faults

We introduce a Self-affine Asperity Model (SAM) for the seismicity that mimics the fault friction by means of two fractional Brownian profiles (fBm) that slide one over the other. An earthquake occurs when there is an overlap of the two profiles representing the two fault faces and its energy is assumed proportional to the overlap surface. The SAM exhibits the Gutenberg-Richter law with an exponent $\beta$ related to the roughness index of the profiles. Apart from being analytically treatable, the model exhibits a non-trivial clustering in the spatio-temporal distribution of epicenters that strongly resembles the experimentally observed one. A generalized and more realistic version of the model exhibits the Omori scaling for the distribution of the aftershocks. The SAM lies in a different perspective with respect to usual models for seismicity. In this case, in fact, the critical behaviour is not Self-Organized but stems from the fractal geometry of the faults, which, on its turn, is supposed to arise as a consequence of geological processes on very long time scales with respect to the seismic dynamics. The explicit introduction of the fault geometry, as an active element of this complex phenomenology, represents the real novelty of our approach.Comment: 40 pages (Tex file plus 8 postscript figures), LaTeX, submitted to Phys. Rev.

Self-affine Asperity Model for earthquakes

A model for fault dynamics consisting of two rough and rigid brownian profiles that slide one over the other is introduced. An earthquake occurs when there is an intersection between the two profiles. The energy release is proportional to the overlap interval. Our model exhibits some specific features which follow from the fractal geometry of the fault: (1) non-universality of the exponent of the Gutenberg-Richter law for the magnitude distribution; (2) presence of local stress accumulation before a large seismic event; (3) non-trivial space-time clustering of the epicenters. These properties are in good agreement with various observations and lead to specific predictions that can be experimentally tested.Comment: TeX file, 14 pages, 3 figures available from [email protected]

[Mariegraphia, seu De laudibus Mariae Virginis]

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Modelling eNvironment for Isoforms (MoNvIso): A general platform to predict structural determinants of protein isoforms in genetic diseases

The seamless integration of human disease-related mutation data into protein structures is an essential component of any attempt to correctly assess the impact of the mutation. The key step preliminary to any structural modelling is the identification of the isoforms onto which mutations should be mapped due to there being several functionally different protein isoforms from the same gene. To handle large sets of data coming from omics techniques, this challenging task needs to be automatized. Here we present the MoNvIso (Modelling eNvironment for Isoforms) code, which identifies the most useful isoform for computational modelling, balancing the coverage of mutations of interest and the availability of templates to build a structural model of both the wild-type isoform and the related variants

Microtremor Measurements in the City of Palermo, Italy: Analysis of the Correlation between Local Geology and Damage

This study presents the results of 90 seismic ambient noise measurements in Palermo, the main city of Sicily (Italy). The dataset has been processed using the horizontal-to-vertical spectral ratio (HVNSR) technique and interpreted in terms of local geology, which is characterized by the presence of alluvial sediments of two riverbeds masked by urbanization since the seventeenth century. HVNSRs show significant variations in the study area: when the transition stiff to soft is crossed, a typical spectral peak appears in the HVNSRs, mostly in the frequency band 1–2 Hz, and exceeding a factor of 3 in amplitude. Using available information on subsurface geological structure, we compute theoretical 1D and 2D transfer functions. The resonance frequencies of soft soils obtained by HVNSR are well reproduced by the fundamental frequencies from numerical modeling. The distribution of frequency peaks of HVNSR and their amplitudes are also compared with the local damage caused by historical earthquakes. Previous studies demonstrated that damage variations in Palermo were controlled more by near-surface geology than building vulnerability. A uniform vulnerability is an ideal condition to test statistical methods and their capability in seeking correlation between HVNSR and potential damage due to local geological conditions. We apply two well-established multivariate statistical methodologies (factor analysis and canonical correlation) to the HVNSR dataset and macroseismic data (damage grades of the European macroseismic scale). Through these analyses we quantify the significance of the correlation between the HVNSR peak in the low-medium frequency range (0.5–3 Hz) and the occurrence of the highest damage grades. This approach allows us (1) to estimate the threshold value in the resulting linear combination of the HVNSR amplitudes, which separates zones of light damage from zones of significant damage, and therefore (2) to improve the spatial definition of potentially high hazard zones through a denser grid of microtremor measurements

Multidisciplinary investigations using historical data, specific experimental surveys, numerical simulations and earthquake data to assess seismic hazard in a densely urbanized city: the study case of Palermo

The city of Palermo (southern Italy) was severely damaged in the past by moderate-magnitude earthquakes located tens of kilometres offshore. The historical monumental heritage and the high density of population motivated large efforts for the seismic risk assessment. We present the geological and seismological studies performed in downtown Palermo as a study case to show how the complexity of an urban environment can be approached with multidisciplinary investigations. Downtown Palermo is characterized by sea deposits in the coastal zone and the alluvial deposits of two rivers (Papireto and Kemonia) of about 150 m width, which were buried and filled during the XVII century. The difficulty of surface geological surveys was compensated through an analysis of aerial photos and more than 2000 borehole data organized in the City-GIS of the Department of Geology and Geodesy of the University of Palermo. A previous study on the well-documented historical damage indicated the major role played by the two river valleys and the sea deposits in controlling the damage distribution, above the assumption of a fairly homogeneous vulnerability of the existing buildings in downtown. To test the feasibility of using ambient noise for recognizing the presence of alluvial deposits in a densely urbanized environment, a large microtremor measurement campaign was performed in Palermo across several profiles. The frequency peaks inferred from the horizontal-to-vertical spectral ratio were compared with numerical simulations to assess the seismic velocity profile and the soil stratigraphy. Moreover, noise data were analyzed through a statistical approach to establish a possible correlation between damage, resonance frequency and amplitude, and geology. After the moderate earthquake of September 6, 2002 (Mw=5.9, 50 km far away), the analysis of the aftershock sequence provided a well documented estimate of the variation of ground motion within the city in the case of linear soil response. Using these aftershocks we computed also synthetic accelerograms of the main shock through Empirical Green’s Functions that provided ground accelerations as large as 50 gals, consistently with the documented EMS-98 intensity. Synthetic accelerograms showed a large variability of horizontal ground motion within the city (a factor of 3 – 4) that confirms the role of local geology in causing an increase of the seismic hazard on sea and alluvial deposits. Finally, we discuss the comparison between the acceleration response spectra calculated for different soil categories and the design elastic spectra provided by EC8

Microtremor Measurements in the City of Palermo, Italy: Analysis of the Correlation with Local Geology and Damage

This study presents the results of 90 seismic ambient noise measurements in Palermo, the main city of Sicily (Italy). The dataset has been processed using the horizontal-to-vertical spectral ratio (HVNSR) technique and interpreted in terms of local geology, which is characterized by the presence of alluvial sediments of two river-beds masked by urbanization since the 17th century. HVNSRs show significant variations in the study area: when the transition stiff-to-soft is crossed, a typical spectral peak appears in the HVNSRs, mostly in the frequency band 1 to 2 Hz, and exceeding a factor of 3 in amplitude. Using available information on sub-surface geological structure we compute theoretical 1- and 2-D transfer functions. The resonance frequencies of soft soils obtained by HVNSR are well reproduced by the fundamental frequencies from numerical modeling. The distribution of frequency peaks of HVNSR and their amplitudes are also compared with the local damage caused by historical earthquakes. Previous studies demonstrated that damage variations in Palermo were controlled more by near-surface geology than building vulnerability. A uniform vulnerability is an ideal condition to test statistical methods and their capability in seeking correlation between HVNSR and potential damage due to local geological conditions. We apply two well-established multivariate statistical methodologies (factor analysis and canonical correlation) to the HVNSR dataset and macroseismic data (damage grades of the European Macroseismic Scale). Through these analyses we quantify the significance of the correlation between the HVNSR peak in the low-medium frequency range (0.5-3 Hz) and the occurrence of the highest damage grades. This approach allows us i) to estimate the threshold value in the resulting linear combination of the HVNSR amplitudes which separates zones of light damage from zones of significant damage, and therefore ii) to improve the spatial definition of potentially high hazard zones through a denser grid of microtremor measurements

Nonuniversal scaling behavior of Barkhausen noise

We simulate Barkhausen avalanches on fractal clusters in a two-dimensional diluted Ising ferromagnet with an effective Gaussian random field. We vary the concentration of defect sites $c$ and find a scaling region for moderate disorder, where the distribution of avalanche sizes has the form $D(s,c,L) = s^{-(1+\tau (c))}{\cal{D}}(sL^{-D_s(c)})$. The exponents $\tau (c)$ for size and $\alpha (c)$ for length distribution, and the fractal dimension of avalanches $D_s(c)$ satisfy the scaling relation $D_s(c)\tau (c) =\alpha (c)$. For fixed disorder the exponents vary with driving rate in agreement with experiments on amorphous Si-Fe alloys.Comment: 5 pages, Latex, 4 PostScript figures include