ABSTRACT
We present here the first attempt to understand the fast dynamics of an active basaltic volcano, namely Mt. Etna using soil gas radon measured in some sites located in strategic places around the volcano. Data were measured continuously from July 2015 to February 2017 and the raw signals were treated in order to filter out all possible periodic components that are normally due to non-volcanic factors, applying a method that does not require acquisition of other parameters, which are not always available. The residual signals highlighted seven anomalous changes, with radon values reaching levels from 2 to 5 times higher than the normal background. In six out of seven cases, anomalies were almost contemporaneous in all or almost all of the sites, indicating a common source for the observed radon variations. The pattern of anomalies suggests a transient wave-like propagation in the space/time domain, compatible with pressure-induced displacement of the gas. The observed patterns are most probably caused by the rapid upward motion of gas-rich magma into the volcano conduits, as almost all anomalies precede or accompany major volcanic events. In some cases, an alternative explanation could be the strong and sudden strain releases through earthquakes swarms, with consequent variations in the permeability of rocks at a large scale, given the apparent correlation between those anomalies and intense seismicity.
Subject(s)
Radiation Monitoring , Radon , Soil Pollutants, Radioactive , Italy , SoilABSTRACT
Indoor navigation technology is needed to support seamless mobility for the visually impaired. A small portable personal navigation device that provides current position, useful contextual wayfinding information about the indoor environment and directions to a destination would greatly improve access and independence for people with low vision. This paper describes the construction of such a device which utilizes a commercial Ultra-Wideband (UWB) asset tracking system to support real-time location and navigation information. Human trials were conducted to assess the efficacy of the system by comparing target-finding performance between blindfolded subjects using the navigation system for real-time guidance, and blindfolded subjects who only received speech information about their local surrounds but no route guidance information (similar to that available from a long cane or guide dog). A normal vision control condition was also run. The time and distance traveled was measured in each trial and a point-back test was performed after goal completion to assess cognitive map development. Statistically significant differences were observed between the three conditions in time and distance traveled; with the navigation system and the visual condition yielding the best results, and the navigation system dramatically outperforming the non-guided condition.
Subject(s)
Blindness/rehabilitation , Algorithms , Biomedical Engineering/methods , Canes , Equipment Design , Humans , Microcomputers , Sensory Aids , Software , User-Computer Interface , Visual Fields , Visually Impaired Persons , WalkingABSTRACT
OBJECTIVES: In recent years numerous clinical trials have been carried out to evaluate homoeopathic therapy. Another approach to evaluating homoeopathy is to investigate its impact in primary health care, that is on outpatients to a homoeopathic centre. METHODS: 609 patients on their first visit to a homoeopathic clinic from June 1995 to May 1997 received a telephone call 1 year later in which they were asked to rate their general health compared with 1 year ago. RESULTS: 1 year after first examination 73.5% of patients reported a marked or moderate improvement in their health status. Marked improvement was significantly higher in subjects who stated they were satisfied with the care received, in females, in the 0-15-year-old age group and in patients who completed therapy. CONCLUSIONS: For conditions which are not life-threatening, homoeopathy seems to meet patients' needs in primary health care.
