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Sindh province is located in the southeastern part of the country and its climate is semi arid to arid. There is great variability in rainfall and the annual average precipitation is 160 mm. This province constitutes the lower Indus plain with a population of about 40 millions. Its peculiar location and topography makes it prone to floods, droughts and sea water intrusion. Groundwater salinity is widespread throughout Sindh. In many parts of the province, groundwater is also polluted with arsenic, fluoride and pathogens. While almost all surface water bodies (canals, lakes and ponds) are highly polluted with sewage, industrial and other wastes. In some areas surface water is also turbid with poor taste and odor. As a result, there is scarcity of fresh and clean water for drinking and other purpose. Moreover, the untreated surface water is supplied from these polluted sources by municipalities to the most of population in Sindh. Consequently, a large section of the population is suffering from gastroenteritis, arsenicosis, skin lesions and dental fluorosis. Present study is based on 200 drinking water samples collected from surface and groundwater sources in nine districts of Sindh (Thatta, Jamshoro, Hyderabad, Matiari, Tando Mohammad Khan, Tando Allayar, Tharparkar, Badin and Nawab Shah). These water samples were analyzed for physical and chemical characteristics to determine (i) suitability for drinking purpose (ii) identify pollution types (iii) trace their geogenic and anthropogenic sources and (iv) suggest mitigation measures. [ABSTRACT FROM AUTHOR]

Motivated by quantum gravity, semiclassical theory, and quantum theory on curved spacetimes, we study the system of an oscillator coupled to two spin-1/2 particles. This model provides a prototype for comparing three types of dynamics: the full quantum theory, the classical oscillator with spin backreaction, and spins propagating on a fixed oscillator background. From calculations of oscillator and entanglement entropy evolution, we find the three systems give equivalent dynamics for sufficiently weak oscillator-spin couplings but deviate significantly for intermediate couplings. These results suggest that semiclassical dynamics with backreaction does not provide a suitable intermediate regime between quantum gravity and quantum theory on curved spacetime.

We show that a class of topological field theories are quantum duals of the harmonic oscillator. This is demonstrated by establishing a correspondence between the creation and annihilation operators and nonlocal gauge invariant observables of the topological field theory. The example is used to discuss some issues concerning background independence and the relation of vacuum energy to the problem of time in quantum gravity.