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Magnetic hard disk drives have undergone vast technological improvements since their introduction as storage devices over 45 years ago, and these improvements have had a marked influence on how disk drives are applied and what they can do. Areal density increases have exceeded the traditional semiconductor development trajectory and have yielded(More)
Magnetic hard disk drives have significantly improved in size, performance and cost due to many technological innovations; including magnetoresistive heads, low noise thin film disks, PRML channels and advanced mechanical actuators and motors. By analyzing specification trends of each new disk drive design, a perspective of this evolution can be developed(More)
The extent of disease as detected by magnetic resonance imaging was compared between 32 patients with benign multiple sclerosis (MS) and 32 patients with the chronic progressive form matched for age, sex, and disease duration. Computer-assisted quantitation of magnetic resonance images revealed a higher mean lesion load in chronic progressive multiple(More)
A prospective study of serial magnetic resonance (MR) scans of the brain was carried out every 2 weeks for 4 to 6 months in 9 patients with mild, clinically definite, relapsing/remitting multiple sclerosis (MS). Six of the 9 patients developed a total of 12 asymptomatic new lesions in various parts of the brain. In none of the patients were the changes on(More)
Although cognitive impairment is commonly associated with Parkinson's disease, the relative importance of cortical and subcortical pathologic changes to the development of dementia is controversial. Characteristic abnormalities in cortical glucose metabolism have been reported previously in Alzheimer's disease, a disease in which cortical changes(More)
Prospective monthly magnetic resonance imaging (MRI) studies were done over 6 months in seven relapsing MS patients. MRI and neurologic evaluations were compared for sensitivity in detecting disease activity. Four patients were clinically stable throughout the study. Three patients had five clinical relapses, two localized to the spinal cord and three to(More)
Eight patients in the chronic progressive stage of multiple sclerosis were studied prospectively with magnetic resonance imaging of the head and neurological examination every 2 weeks for 6 months. There were no clinical relapses and disability ratings did not change between the start and completion of the study. Despite the clinical inactivity, a total of(More)
The purpose of this paper is to describe a method for determining whether a particular procedure for estimating regional metabolism using the deoxyglucose tracer analogue yields better data than another in terms of subsequent statistical analysis. The method is based on a simple model of regional cerebral glucose metabolism with three potential sources of(More)
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