spect detects γ-rays from administered radiopharmaceutical within the patient body. γ-rays pass through different tissues before reaching detectors and are attenuated. attenuation can cause artifacts; therefore different methods are used to minimize attenuation effects. in our study efficacy of chang method was evaluated for attenuation purpose, using a custom made heart phantom. due to differe...

Lakes are important water resources and integral parts of the natural ecosystem, and it is of great significance to study the evolution of lakes. The area of each lake increased and decreased at the same time in natural condition, only but the net change of lakes’ area is the result of the bidirectional evolution of lakes. In this paper, considering the effects of net fragmentation, net attenua...

Distributed attenuation in flood management relies on small and low-impact runoff attenuating features variously distributed within a catchment. systems of reservoirs, natural management, green infrastructure are practical examples attenuation. The effectiveness lies their ability to work concert, by reducing slowing strategic parts the catchment, desynchronizing flows. spatial distribution pla...

Advancement of Nucleic Acid-Based Tools for Monitoring In Situ Reductive Dechlorination Vangelas, K., E. Edwards, F. Loeffler, B.B. Looney. Paper No: WSRC-STI-2006-00332, 23 pp, Nov 2006 Regulatory protocols generally recognize that destructive processes are the most effective mechanisms that support natural attenuation of chlorinated solvents. In many cases, these destructive processes will be...

An in situ experimental study of variations of compressional wave speed and attenuation with depth in natural coral sands has been made offshore of Oahu, Hawaii. In situ data were collected at a center frequency of 7.5 kHz. Compressional wave speed averages around 1620 m/s and attenuation ~expressed as Qp , the reciprocal of the quality factor! decreases from 0.04 at the seafloor to 0.01 at 2 m...

Bioremediation of diesel oil in soil can occur by natural attenuation, or treated by biostimulation or bioaugmentation. In this study we evaluated all three technologies on the degradation of total petroleum hydrocarbons (TPH) in soil. In addition, the number of diesel-degrading microorganisms present and microbial activity as indexed by the dehydrogenase assay were monitored. Soils contaminate...

We present a method for estimating seismic attenuation based on frequency shift data. In most natural materials, seismic attenuation increases with frequency. The high-frequency components of the seismic signal are attenuated more rapidly than the low-frequency components as waves propagate. As a result, the centroid of the signal’s spectrum experiences a downshift during propagation. Under the...

Climate change impacts and light attenuation from suspended sediments, due to runoff, natural resuspension or dredging, can both impede the replenishment of coral populations. Here we tested independent combined climate (current temperature dissolved CO 2 , future scenarios) a 1 mo long period at 5 different levels (0.1 4 mol photons m -2 d -1 ) on early Acropora millepora recruits. Additionall...

Premature delivery is the leading cause of infant mortality in the United States. Currently, premature delivery cannot be prevented and new treatments are difficult to develop due to the inability to diagnose symptoms prior to uterine contractions. Cervical ripening is a long period that precedes the active phase of uterine contractions and cervical dilation. The changes in the microstructure o...