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A recent study shows that computation per kilowatt-hour has doubled every 1.57 years, akin to Moore's Law. While this trend is encouraging, its implications to high-performance computing (HPC) are not yet clear. For instance, DARPA's target of a 20-MW exaflop system will require a 56.8-fold performance improvement with only a 2.4-fold increase in power(More)
Patients with seropositive and seronegative rheumatoid arthritis (RA) and age-matched controls were investigated for the presence of autonomic neuropathy. Significantly more patients with RA had abnormal autonomic function, suggesting that autonomic neuropathy occurs more commonly in RA than hitherto suspected. The existence of an autonomic neuropathy may(More)
A few patients may be of normal intelligence but have difficulties in reading, writing, and spelling, which are the main precipitants of a psychiatric disorder. In seven patients this illiteracy emerged only after intensive examination, as they had hidden it from employers, friends, and children. Characteristically these patients are often very sensitive(More)
Clinical and radiographic assessment of the spine was carried out in 75 patients with osteoarthrosis (OA) of the hip and in 75 controls without hip disease. Radiographic degenerative changes in the spine were more frequent in the patients with OA hips, occurring in both the dorsal and lumbar spine. Moderate or severe changes were found in the dorsal spine(More)
The synthesis of luminescent nanometer-scale Si clusters by spark ablation from a crystalline Si substrate is described. The cluster source, described in the text, generates clusters in a flowing Ar stream at atmospheric' pressure. Electron microscopy reveals that the clusters have diameters in the 2-4 nm size range. The luminescence spectra of the(More)
Four women presented with symptomatic hypercalcaemia and raised concentrations of serum parathyroid hormone (PTH). In each case, serum calcium returned spontaneously to normal. In two patients serum PTH also fell to the normal range and biochemical relapse has not occurred despite prolonged follow-up. In the others, serum PTH remained elevated and(More)
We report the synthesis of crystalline nanometer-scale GaAs clusters by homogeneous vapor-phase nucleation from organometallic precursors. Cluster synthesis is performed in a hot wall organometallic vapor-phase epitaxy reactor at atmospheric pressure. High resolution transmission electron microscopy studies reveal that the aerosol produced is composed of(More)