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Seismic refraction tomography (SRT) involves more complex mathematic algorithms to fit more flexible model. In the field procedure SRT in generally needs more shot points than standard seismic refraction survey to obtain high resolution profile. In this seismic refraction study, we have used 9 shot-points for inline and 10 shot-points for offset in purpose to obtaine high resolution of seismic refraction tomography. During a recent geophysical test site, the subsurface material was mapped along survey line using seismic refraction method. Analyses of the site investigation data revealed that the studied site was made up of two layers of the subsurface. The upper layer has velocity values with range of 500 m/s to1500 m/s which can be classified as unconsolidated surface deposits and mixtures of unsaturated sands and gravels. Meanwhile the lower layer has velocity values with range of2000 m/s to5500 m/s which is classified as compacted fine’s soil due to high pressure of the overburden. Analysis of seismic refraction data demonstrated that refraction tomography software systems are able to reveal subsurface material which represented by their seismic velocity value. Furthermore, the velocity model obtained in this study is agreed with its synthetic modelling result as initial model. This validity and reasonable results was able to assist in interpretation of the seismic refraction method for the environmental study.
Objectives: 1) To describe electroencephalogram (EEG)
appearance in the awake dog and compare these results with EEG recordings after
low dose medetomidine (2 μg/kg IV) followed by atipamezole (10 μg/kg, IM); 2) To
institute EEG recordings after low dose medetomidine or dexmedetomidine as a
standard of practice if focal abnormalities and amplitudes were not
significantly altered by pharmaceuticals in Phase 1 of this study. Methods:
Electroencephalograms were performed on eight clinical canine patients with
suspected intracranial disease involving the prosencephalon. A five lead montage
was used to record the EEGs. Each dog had an awake, baseline recording followed
by an EEG performed after administration of low dose medetomidine (2 μg/kg IV)
then atipamezole (10 μg/kg, IM). In the second phase of this study, the same
dose of medetomidine or dexmedetomidine at 1 μg/kg IV and atipamezole (10
μg/kg, IM) were used in the evaluation of 20 clinical patients with suspected
neurologic disease. Results: In Phase 1, awake recordings were laced with movement artifacts.
After medetomidine and atipamezole, EEG waveforms were slower. Following
atipamezole, however, the frequencies were observed to increase with time.
Statistical evaluation revealed significantly more artifacts in baseline
recordings. No statistically significant change was observed in focal
abnormalities or amplitude. In Phase 2, the a2-adrenoreceptor agonists followed by atipamezole without the use of
lidocaine produced clinically reliable results. Clinical Significance:
Quality and diagnostic electroencephalogram (EEG) recordings are frequently
inconvenient to obtain in the awake dog. Movement results in artifacts and
dislodged leads. Administration of low dose medetomidine or dexmedetomidine
followed by atipamezole reliably reduced the impact of movement artifacts and
produced clinically valid EEG recordings in dogs.