Browsing by Author "Johnson, A. L."
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Equine Protozoal Myeloencephalitis: An Updated Consensus Statement with a Focus on Parasite Biology, Diagnosis, Treatment, and PreventionReed, S. M.; Furr, M. O.; Howe, D. K.; Johnson, A. L.; MacKay, R. J.; Morrow, J. K.; Pusterla, N.; Witonsky, Sharon G. (American College of Veterinary Internal Medicine, 2016-03)Equine protozoal myeloencephalitis (EPM) remains an important neurologic disease of horses. There are no pathognomonic clinical signs for the disease. Affected horses can have focal or multifocal central nervous system (CNS) disease. EPM can be difficult to diagnose antemortem. It is caused by either of 2 parasites, Sarcocystis neurona and Neospora hughesi, with much less known about N. hughesi. Although risk factors such as transport stress and breed and age correlations have been identified, biologic factors such as genetic predispositions of individual animals, and parasite-specific factors such as strain differences in virulence, remain largely undetermined. This consensus statement update presents current published knowledge of the parasite biology, host immune response, disease pathogenesis, epidemiology, and risk factors. Importantly, the statement provides recommendations for EPM diagnosis, treatment, and prevention.
- Ultrasonic water measurement in irrigation pipelines with disturbed flowJohnson, A. L.; Benham, Brian L.; Eisenhauer, D. E.; Hotchkiss, R. H. (American Society of Agricultural and Biological Engineers, 2001)Ultrasonicflow meter accuracy was investigated over a range of flow conditions (3 pipe materials, 2 pipe sizes, 4 Reynolds numbers, 7 flow-disturbing devices) commonly found in irrigation systems. Flow rate measurements were taken at five locations downstream from a flow disturbance. The measurement accuracy was within +/-5% of actual flow at a minimum of 10 pipe diameters downstream from the flow disturbances. Errors as high as 36.5% occurred when measurements were taken close to some flow disturbances. A multiplier was developed to correct for directional bias for devices that fell into the Group I category (single elbow, two elbows, check valve, and 50% open butterfly valve with vertical and horizontal orientation). Applying the multiplier at 4.5 pipe diameters and higher resulted in accuracies within +/-4% of actual flow. The regression analysis performed on Group I devices showed that the USFM performance was not significantly different for the three pipe materials, two pipe diameters, and four flow rates.