We review existing estimates of the size of the Spanish underground economy, apply the Ahumada et al. (2007, RIW) correction procedure to some of them and calculate the size of the underground economy in Spain for the period 1960 through 2009 by using the modified-cash-deposits-ratio (MCDR) approach recently developed by Pickhardt and Sardà (2011, EJLE). We then extend the MCDR approach with re...

background: in this study are submitted the radon concentration measurement results of four underground mines: stanterg, artana, hajvali and badovc, which are owned by trepça enterprise, kosovo. the mines have the same geological formation and from these mines are extracted ores rich with lead, zinc, silver, and gold. the radiation exposures caused by radon and radon daughters was determined an...

This Conference has brought together many insights into the learning of algebra, and into aspects of teaching that can help students to understand and do it better. Here I want mainly to comment on what else may be needed to turn these insights into actual improvements in learning in school classrooms around the world. Some of these comments are specific to algebra; others apply more widely, to...

In this paper, a method of mathematical modeling for solving the problem reusing man-made waste from mining and processing ores is proposed. The use intermediate products (man-made waste: tailings plants, rocks sinking operations technical water mine drainage) in cyclic production presupposes their as fill material components placement mined-out voids underground mines. influence factors on com...

1. Mycorrhizal symbiosis is thought to affect interactions between plants and herbivores by its influence on plant growth, nutrition and the plants defence system. Moreover, arbuscular mycorrhizal fungi (AMF) may enhance the inducibility of resistance responses. Until now, induction of plant resistance has not been considered to be a mechanism affecting the outcome of mycorrhization for plant-h...

Potajnice (intermittent/rhythmic springs) are a rare hydrographic phenomenon exclusively present in karst areas. They appear as result of the rising and emptying siphon underground reservoir, while phases when water flows over drains down most frequently last for several minutes or hours. often accompanied by distinct noise (rumbling, sizzling, bursting) which adds to mysteriousness this phenom...