Presentation of the ISRM mine closure state of the art report

International audienceIn 2005, Prof. Nielen Van der Merwe, at that time President of the ISRM, initiated a commission to facilitate the constitution of an international network of experts involved in mine closure and post-mining management. Eight experts coming from different countries have been deeply involved in this ISRM 'mine closure commission', for four years. Closure of mining operations does not lead to the complete elimination of risks likely to affect the surface above old mine workings. Therefore, disorders potentially harmful for people and goods may develop, sometimes just after the closure but also, in some cases, long time after. The first mandate of the commission has been dedicated to the elaboration of a state-ofthe- art report presenting, at an international scale, the mine closure problem (context, main risks of disorders, major hazard assessment methods and treatment techniques). The present paper presents an outline of this ISRM report that members may download on the ISRM website

Regulation of human CD4+ T cell differentiation

Naive CD4+ T cells differentiate into specific effector subsets—Th1, Th2, Th17, and T follicular helper (Tfh)—that provide immunity against pathogen infection. The signaling pathways involved in generating these effector cells are partially known. However, the effects of mutations underlying human primary immunodeficiencies on these processes, and how they compromise specific immune responses, remain unresolved. By studying individuals with mutations in key signaling pathways, we identified nonredundant pathways regulating human CD4+ T cell differentiation in vitro. IL12Rβ1/TYK2 and IFN-γR/STAT1 function in a feed-forward loop to induce Th1 cells, whereas IL-21/IL-21R/STAT3 signaling is required for Th17, Tfh, and IL-10–secreting cells. IL12Rβ1/TYK2 and NEMO are also required for Th17 induction. Strikingly, gain-of-function STAT1 mutations recapitulated the impact of dominant-negative STAT3 mutations on Tfh and Th17 cells, revealing a putative inhibitory effect of hypermorphic STAT1 over STAT3. These findings provide mechanistic insight into the requirements for human T cell effector function, and explain clinical manifestations of these immunodeficient conditions. Furthermore, they identify molecules that could be targeted to modulate CD4+ T cell effector function in the settings of infection, vaccination, or immune dysregulation

geo-archaeological evidence and its geotechnical aspects

The western Aegean region of Turkey is highly populated; the centrally-located city of Izmir is the third largest city in Turkey. This region has suffered very large earthquakes in the past, of which one of the most devastating occurred in 1928. Some areas are particularly prone to severe ground liquefaction. This study is concerned with the earthquake potential of the region, focusing on a possible earthquake faulting mechanism and its associated characteristics based on historical and current regional seismicity, tectonics, crustal deformation and geo-archaeological evidence. The first part of the study presents a faulting mechanism, tectonics, recurrences and the fundamental characteristics of existing faults and past earthquakes. Then, the characteristics of potential earthquakes are discussed in light of evaluations of recent crustal deformation and empirical relations developed for Turkey by the first author. The final part presents geotechnical aspects, including liquefaction and the characteristics of strong ground motions recorded in the region, such as spectral acceleration, attenuation of maximum ground acceleration and velocity. Furthermore, their possible implications are discussed in view of current Turkish seismic design codes. The faulting mechanism of regional earthquakes has indicated that the classical horst-graben concept does not explain the earthquake mechanism in the region of concern. The magnitude of earthquakes inferred from the length and type of known active faults may be up to 7.7. Based on an evaluation of crustal deformation in the region, the highest disturbing stress and mean stress concentration with a compressive character occurs in close proximity to A degrees zmir. The spectral accelerations generally exceed those of Turkish seismic design codes. The liquefaction potential in areas of alluvial quaternary deposits is particularly high and is one of the major geotechnical issues in light of historical records and evaluations presented in this manuscript

An integrated study on the stability assessment and partial collapse of the Kaklik karstic cave (Denizli, Turkey)

The Kaklik Cave (Denizli, Turkey) was found following a partial collapse while a tractor was plowing a field. Since then, it is arranged for tourist visits and its stability assessment is of great importance for visitors. The authors have been carrying out geological, rock mechanics, and environmental investigations in the cave since 2003. The authors present the outcomes of these investigations in this study. On the basis of these investigations, the rock mass classifications of the cave were first done, and then its stability including the partial collapse section was evaluated using empirical and analytical methods and compared with in situ observations and other case history data. Finally, the stability and the triggering effect of the tractor on its partial collapse as a concentrated load on the ground surface were analyzed by a numerical method utilizing the discrete finite element method (DFEM), which allows the slip and separation along discontinuities and is based on an updated Lagrangian concept. The empirical, analytical, and numerical stability analyses have been investigated in detail, and it was found that the dead weight of the tractor plowing the field on the ground surface had a triggering effect on the partial collapse of the cave

Response of Rock Wedges under Dynamic Loading

The stability of rock slopes under dynamic loading in mining and civil engineering depends upon the slope geometry, mechanical properties of rock mass and discontinuities, and the characteristics of dynamic loads with time. The wedge failure is one of the common forms of slope failures. The authors presented some stability conditions for rock wedges under dynamic loading and they confirmed their validity through the laboratory experimental studies in a previous paper in 2000, which is often quoted by others to validate their softwares, including some commercial software. In this study, the authors investigate the sliding responses of rock wedges under dynamic loads rather than the initiation of wedge sliding. First, some laboratory model tests are described. On the basis of these model tests on rock wedges, the theoretical model proposed previously is extended to compute the sliding responses of rock wedges in time domain. The proposed theoretical model is applied to simulate the sliding responses of rock wedge model tests and its validity is discussed. In the final part, the method proposed is applied to actual wedge failures observed in 1995 Dinar earthquake and 2005 Pakistan-Kashmir earthquake, and the results are discussed

How to infer the possible mechanism and characteristics of earthquakes from the striations and ground surface traces of existing faults

The instrumented period for earthquakes is relatively short to understand their mechanism and characteristics in many countries. Even at present time, there are many areas in the world where seismic instruments are still insufficient. Therefore, it is very difficult to know the mechanism and the characteristics of future earthquakes in any place because of either the lack of instrumentation and/or the shortness of the instrumented period. In this article, the authors present a methodology for inferring the possible mechanism and characteristics of earthquakes from the ground surface traces and striations of existing faults. The methodology is then applied to the faults of certain locations in Turkey and compared with actual observations in order to see its validity and applicability. © 2002, Japan Society of Civil Engineers. All rights reserved

Elastic Networks in Reshaping Human Intentions by Proactive Social Robot Moves

This paper focuses on reshaping a previously detected human intention into a desired one, using contextual motions of mobile robots, which are in our applications, autonomous mobile 2-steps stairs and a chair. Our system first estimates the current intention based on human heading and trajectory depicted as orientation and location. Our previous reshaping applications have shown that the current human intention has to be deviated towards the new desired one in phases. In our novel approach, Elastic network generates way points of trajectories each of which acts as transient trajectories directed towards the desired intention's location. Our methodology aims at generating an "intention trajectory" towards the final goal. The initial way points possess destabilizing effects on the obstinance of the person intention making the "robot gain the curiosity and the trust of the person". Each way point generated by the elastic network is executed by moves of an adequate robot (here mobile 2-steps or chair) in adequate directions (towards coffee table, PC, TV, library). After each robot moves, the resulting human intention is estimated and compared to the desired goal in the intention space. Intention trajectories are searched in two modes: the "confident mode" and the "suspicious mode" which are defining human body-mood detected relying on proxemics. This paper analyzes our novel approach of planning trajectories via elastic networks based on these two modes