Modeling the evolution of natural cliffs subject to weathering. 2, Discrete element approach

The evolution of slopes subjected to weathering has been modeled by assuming Mohr-Coulomb behavior and by using a numerical approach based on the discrete element method (DEM). According to this method, soil and/or rock are represented by an assembly of bonded particles. Particle bonds are subject to progressive weakening, and so the material weathering and removal processes are modeled. Slope instability and material movement follow the decrease of material strength in space and time with the only assumption concerning the weathering distribution within the slope. First, the case of cliffs subject to strong erosion (weathering-limited conditions) and uniform weathering was studied to compare the results of the DEM approach with the limit analysis approach. Second, transport-limited slopes subject to nonuniform slope weathering were studied. Results have been compared with experimental data and other geomorphologic models from the literature (Fisher-Lehmann and Bakker–Le Heux). The flux of material from the slope is modeled assuming degradation both in space and time

Firing at Subcontractors? Spillover Employment Effects of Offshoring in Italy

Using firm-level data for Italy, we address the employment consequences of international production offshoring. We concur with previous literature that offshoring firms’ individual employment performances are no worse than at matching non-offshoring firms. However, offshoring might impart negative spillover effects on subcontracting firms, and this indirect effect might be felt particularly in Italy’s industrial structure (small-sized networked enterprises). To study this, we group firms within their typical subcontracting clusters, identify high offshoring clusters and compare them with a matching low offshoring sample. The evidence that employment performances worsen in the productive clusters with high offshoring supports our conjecture.International outsourcing, multinational firms, employment effects, propensity

A policy-sensible core-inflation measure for the euro area

Although the concept of core inflation is apparently well defined and intuitively appealing, its practical usefulness has often been questioned on at least two accounts: first, existing core inflation measures are by and large exclusively based on statistical criteria and thus lack a firm theoretical justification; second, there appears to be no generally accepted and plausible criterion to assess the empirical performance of competing measures. Both criticisms are indeed justified. In this paper we propose an approach to build a benchmark measure of core inflation that aims to overcome those drawbacks. Our measure is based on a criterion that explicitly treats core inflation as a wholly artificial concept whose usefulness rests only on its role in defuse inflationary pressures that may be in the pipeline. Our measure is obtained by conveniently combining disaggregate information coming from price sub-indices, as is the case for the most popular core inflation measures. However, we depart from all other approaches by combining the information available in price sub-indices in such a way so as to provide the best guidance to a forward-looking monetary policy-maker. Accordingly, our measure of core inflation is based on the solution of a standard monetary policy optimisation problem. We illustrate our approach using a simple estimated model of the euro-area economy and appraise the performance of a few of the most popular core inflation measures in use. We find, generally speaking, that one cannot recommend that those measures be used to support monetary policy-making.core inflation, optimal monetary policy rules, Eurosystem

Large scale homophily analysis in twitter using a twixonomy

In this paper we perform a large-scale homophily analysis on Twitter using a hierarchical representation of users' interests which we call a Twixonomy. In order to build a population, community, or single-user Twixonomy we first associate "topical" friends in users' friendship lists (i.e. friends representing an interest rather than a social relation between peers) with Wikipedia categories. A wordsense disambiguation algorithm is used to select the appropriate wikipage for each topical friend. Starting from the set of wikipages representing "primitive" interests, we extract all paths connecting these pages with topmost Wikipedia category nodes, and we then prune the resulting graph G efficiently so as to induce a direct acyclic graph. This graph is the Twixonomy. Then, to analyze homophily, we compare different methods to detect communities in a peer friends Twitter network, and then for each community we compute the degree of homophily on the basis of a measure of pairwise semantic similarity. We show that the Twixonomy provides a means for describing users' interests in a compact and readable way and allows for a fine-grained homophily analysis. Furthermore, we show that midlow level categories in the Twixonomy represent the best balance between informativeness and compactness of the representation