BACKGROUND Age-related chronic diseases are prevalent in HIV-infected persons in the antiretroviral therapy (ART) era. Bone mineral density (BMD) loss and emphysema have separately been shown to occur at a younger age and with lesser risk exposure in HIV-infected compared to HIV-uninfected individuals. In non-HIV infected smokers, emphysema has been shown to independently predict low BMD. We hy...

bioremediation, the process by which microorganisms degrade organic compounds to non-toxic or less toxic substances, has been widely used for cleanup of coastal ecosystems after oil spills. in this study, the hydrocarbon degradation rate and half lives in three bioremediation strategies (natural attenuation, biostimulation, and bioaugmentation) were compared in weathered crude oil (wco) contami...

1. We have examined the relationship between broadband ultrasound attenuation in the os calcis and measurements of bone mineral in the distal forearm and lumbar spine of normal and postmenopausal osteoporotic women. 2. Values of broadband ultrasound attenuation in postmenopausal women with vertebral osteoporotic fractures were significantly lower (35%) than in normal pre- and peri-menopausal wo...

The limiting uncertainty in recent high accuracy measurements of the mass attenuation coefficient is the measurement of the integrated column density. An improvement in the design of the absorption foil holder is described which reduces the integrated column density uncertainty. The new design allows the edges of the foil to be more accurately mapped by the X-ray beam by reducing the largest so...

We describe an experimental setup specifically designed for measuring the ultrasonic transmission through liquid foams, over a broad range of frequencies (60-600kHz). The question of determining the ultrasonic properties of the foam (density, phase velocity and attenuation) from the transmission measurements is addressed. An inversion method is proposed, tested on synthetic data, and applied to...

[1] We investigate the ionospheric conditions required to explain Mars Express Mars Advanced Radar for Subsurface and Ionosphere Sounding topside radar sounder observations of ionospheric attenuation in excess of 13 dB at 5 MHz during solar energetic particle events. We develop theoretical expressions for the attenuation caused by a layer of ionospheric plasma in cases of high, intermediate, an...

A model of attenuation of ultrasound in fibre suspensions is compared to a model of backscattering pressure from submersed cylinders subjected to a sound wave. This analysis is carried out in the region where the wavelength is of the same order as that of the diameter of the fibre. In addition we assume the cylinder scatterer to have no intrinsic attenuation and the longitudinal axis of the sca...

Attenuation from fish can reduce the intensity of acoustic signals and significantly decrease detection range for long-range passive sensing manmade vehicles, geophysical phenomena, vocalizing marine life. The effect attenuation herring shoals on Passive Ocean Acoustic Waveguide Remote Sensing (POAWRS) surface vessels is investigated here, where concurrent wide-area active (OAWRS) used to confi...

[1] The influence of density variation on scattering is investigated in terms of attenuation, coda level, and apparent frequency shift. The influence of density variations is to producemore scattered energy than for velocity perturbations alone with a consequently higher coda level. The temporal decay of the coda is reduced, so that high perturbations in density are associated with a long durat...

Background: Radiation shielding properties is an important for a material wish can be used the photon attenuation coefficients of clay produced using different rate of boron have been measured for the purpose of radioactive waste disposal. Materials and Methods: The measurement has been performed using gamma spectrometer contains NaI (Tl) detector at the photon energies of 662, 1173 an...