Earthen construction: structural vulnerabilities and retrofit solutions for seismic actions

Earthen structures present very appealing characteristics regarding a more sustainable practice with the preservation of our natural resources. However, when subjected to earthquake ground motions, this type of construction may present a deficient performance, which may cause significant human losses and important structural damage. The seismic response of earthen structures is typically characterized by fragile failures. There are several examples of recent earthquakes that affected earthen buildings in a severe way, evidencing the vulnerability of this type of construction, like the El Salvador earthquake, in 2001, the Bam, Iran earthquake, in 2003, the Pisco, Peru earthquake, in 2007 and the Maule, Chile earthquake, in 2010. The construction of earth structures on earthquake-prone areas must be carefully studied and should include seismic reinforcement solutions in order to improve their seismic performance. In this paper, the performance of earthen structures in recent earthquakes will be examined, analyzing failure modes inherent to these particular construction materials and associated construction techniques. Also, seismic reinforcement approaches and techniques will be presented in a comprehensive manner. Examples of tests conducted for the assessment of retrofitting solutions efficiency will be presented, and the results obtained will be discussed

Violence and growth in colombia: a review of the quantitative literature

ABSTRACTThis is a critical review of the empirical literature on the relationship between violence and economic growth in Colombia: an interesting case study for social scientists studying violence, conflict, crime and development. We argue that, despite the rapid development of this literature and the increasing use of new techniques, there is still much room for research. After assessing the contribution of the most influential papers on the subject, we suggest directions for future research.Colombia, Violence, Economic Growth

Semantic web-based document: editing and browsing in AktiveDoc

This paper presents a tool for supporting sharing and reuse of knowledge in document creation (writing) and use (reading). Semantic Web technologies are used to support the production of ontology based annotations while the document is written. Free text annotations (comments) can be added to integrate the knowledge in the document. In addition the tool uses external services (e.g. a Semantic Web harvester) to propose relevant content to writing user, enabling easy knowledge reuse. Similar facilities are provided for readers when their task does not coincide with the author’s one. The tool is specifically designed for Knowledge Management in organisations. In this paper we present and discuss how Semantic Web technologies are designed and integrated in the system

Experimental phase functions of mm-sized cosmic dust grains

We present experimental phase functions of three types of millimeter-sized dust grains consisting of enstatite, quartz and volcanic material from Mount Etna, respectively. The three grains present similar sizes but different absorbing properties. The measurements are performed at 527 nm covering the scattering angle range from 3 to 170 degrees. The measured phase functions show two well defined regions i) soft forward peaks and ii) a continuous increase with the scattering angle at side- and back-scattering regions. This behavior at side- and back-scattering regions are in agreement with the observed phase functions for the Fomalhaut and HR 4796A dust rings. Further computations and measurements (including polarization) for millimeter sized-grains are needed to draw some conclusions about the fluffy or compact structure of the dust grains

Non-Hermitian robust edge states in one-dimension: Anomalous localization and eigenspace condensation at exceptional points

Capital to topological insulators, the bulk-boundary correspondence ties a topological invariant computed from the bulk (extended) states with those at the boundary, which are hence robust to disorder. Here we put forward an ordering unique to non-Hermitian lattices, whereby a pristine system becomes devoid of extended states, a property which turns out to be robust to disorder. This is enabled by a peculiar type of non-Hermitian degeneracy where a macroscopic fraction of the states coalesce at a single point with geometrical multiplicity of $1$, that we call a phenomenal point.Comment: 6 pages, 4 figure