Log-mean linear models for binary data

This paper introduces a novel class of models for binary data, which we call log-mean linear models. The characterizing feature of these models is that they are specified by linear constraints on the log-mean linear parameter, defined as a log-linear expansion of the mean parameter of the multivariate Bernoulli distribution. We show that marginal independence relationships between variables can be specified by setting certain log-mean linear interactions to zero and, more specifically, that graphical models of marginal independence are log-mean linear models. Our approach overcomes some drawbacks of the existing parameterizations of graphical models of marginal independence

Seismic vulnerability maps of Timisoara historical center based on fragility curves

The seismic vulnerability assessment on a territorial scale requires the application of simplified procedures. Data collection is usually carried out by adopting external inspections; for this reason the knowledge gained for the considered buildings is usually not complete and lack of information has to be managed. The definition of a methodology which takes into account these aspects is one of the aims of this paper. Another goal is the extension of the obtained results to buildings not directly surveyed on site, whose characteristics are similar to those of the analyzed buildings. The case study of Timisoara (Romania) is presented. A rapid survey of the historical center is performed and recurring typologies are identified. Analyses of the most significant local mechanisms of collapse are implemented, taking into account possible parameters variation. Fragility curves for each typology are then obtained allowing the definition of vulnerability maps for the whole historical center

Holocene paleo-earthquakes recorded at the transfer zone of two majorfaults: the Pastores and Venta de Bravo fault (Trans-Mexican Volcanic Belt).

We present evidence of fi ve late Holocene earthquake ruptures observed at two paleoseismological trenches in the Laguna Bañí sag pond (Trans-Mexican Volcanic Belt, central Mexico). The trenches exposed two fault branches of the western termination of the Pastores fault, one of the major fault systems within the central Trans-Mexican Volcanic Belt. The site was studied by combining geomorphological and structural approaches, volcanic mapping, ground-penetrating radar, and paleoseismological analysis. The study revealed that coseismic surface rupture was noncharacteristic, and that the exposed fault branches had not always moved simultaneously. The fault tip has ruptured at least 5 times within the past 4 k.y., and the rupture events followed and preceded the deposition of an ignimbrite. The close temporal relationship of the seismic rupture with the volcanic activity of the area could be the result of volcanism triggered by faulting and its associated seismicity. The relatively high recurrence of seismic events (1.1 2.6 k.y.) and the noncharacteristic fault behavior observed at this tip of the Pastores fault suggest that the fault might have been active as a primary fault rupturing along segments of variable length or depth, and/or that the fault ruptured eventually as a secondary fault. The secondary ruptures would likely be related to earthquakes produced at major neighboring faults such as the Acambay fault, which moved during the 1912 Acambay earthquake, or the Venta de Bravo fault. A relatively large slip rate estimated for this fault branch (0.23 0.37 mm/yr) leads us to contemplate the possible connection at depth between the Pastores and the Venta de Bravo faults, increasing the maximum expected magnitude for central Mexico

Grain size distribution and sedimentology in volcanic mass-wasting flows: implications for propagation and mobility

The sedimentological characteristics of mass-wasting flow deposits are important for assessing the differences between phenomena and their propagation and emplacement mechanisms. In the present study, nine volcanic debris avalanche deposits and eight lahar deposits are considered, from the literature. Their sedimentology is expressed in the descriptive statistics: median grain size, sand, gravel and finer particle fractions, skewness and sorting. Analysis of the data confirms that lahars and debris avalanches diverge in their grain size distribution and in their evolution during propagation. Water saturation in lahars is the main factor enabling debulking, a mechanism that is not recorded in the data derived from debris avalanches deposits. On the contrary, evidence of comminution of particles due to particle-particle interactions is observed in debris avalanches, and not in lahars. These findings support previous studies suggesting that although water content in debris avalanches plays a role in propagation, the effects of inertial collision of solid fragments are more important than fluid effects, confirming that particle-particle interactions are the main factor influencing the mobility of non-saturated mass wasting flows

Gateways as inter-modal nodes in different ages: The Venetian region, eighteenth to twentieth centuries

This paper focuses on the theoretical implications of a regional case studyfor the analysis of transportation networks and gateway functions. Thestarting point is the result of a research on the changing role of gateways,and on the relocation of the gateway function from one city to a series ofcities in the Venetian region from the eighteenth to the twentieth century.Against this evolution, I test the validity and usefulness of a definition of thegateway as a point of inter-modal exchange for its historical interpretation.Changing transport technologies involve different organisations of inter-modal exchanges, and imply more or less intense economic functions ofgateway cities. These changes intertwine with political events and deci-sions, and more general economic changes: they could at the same time beread as an effect of these transformations, and as a causal factor. From this perspective, a study of intermodality shows to be useful to shed new lighton specific changes in the structure of urban hierarchie

Premature Age-Related Comorbidities Among HIV-Infected Persons Compared With the General Population

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