This study looked at output levels produced by new generation personal music systems (PMS), at the level of eardrum by placing the probe microphone in the ear canal. Further, the effect of these PMS on hearing was evaluated by comparing the distortion product otoacoustic emissions and high frequency pure tone thresholds (from 3 kHz to 12 kHz) of individuals who use PMS to that of age matched controls who did not use PMS. The relationship between output sound pressure levels and hearing measures was also evaluated. In Phase I output SPLs produced by the PMS were measured in three different conditions - a) at volume control setting that was preferred by the subjects in quiet b) at volume control setting that was preferred by the subject in presence of 65 dB SPL bus noise c) at maximum volume control settings of the instrument. In Phase II pure tone hearing thresholds and DPOAEs were measured. About 30% of individuals in a group of 70 young adults listened to music above the safety limits (80 dBA for 8 hours) prescribed by Ministry of Environment and Forests, India. Addition of bus noise did not increase the preferred volume control settings of the subjects significantly. There were no significant differences between the experimental and control groups for mean pure tone threshold and for mean DPOAE amplitude comparisons. However, a positive correlation between hearing thresholds and music levels and a negative correlation between DPOAE measures and music levels were found.
Organic waste management is a growing issue due to the unsustainable practices of its disposal. Sewage treatment plants are designed to treat wastewater to produce a safe effluent. However, one of the by-products, the sewage sludge which is disposed off in landfill or used as fertilizer in agricultural operation is high in pathogens. Sustainability can be achieved by Vermicomposting of organic matter which involves accelerated cycling of nutrients though a closed cycle whereby waste products are put to productive end use. Vermicomposting and vermifiltration are natural waste management processes relying on the use of worms to convert organic wastes to stable soil enriching compounds. Domestic wastewater management can be accommodated through these processes in a sustainable manner. A considerable reduction in pathogens has been noticed in the end product to a level that it can be safely applied to land. This paper provides an overview of the system characteristics of management systems utilising vermiculture, to manage wastewater. The process can be used in a small scale for household waste treatment to rural or urban waste management.
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