723 research outputs found
An algorithm for solving nonlinear equations arising from nonsmooth optimization problems via some generalized Newton method (Mathematical Decision Making under uncertainty and ambiguity)
Wave Packet Propagation and Electric Conductivity of Nanowires
We compute the electric conductivity of nanowires in the presence of magnetic
domain walls by the method of wave packet propagation. We demonstrate that the
propagation through the wire depends on the initial state used in the wave
packet simulation. We propose a procedure, based on the Landauer formula, to
reduce this dependence. Direct numerical calculations of the Kubo formula for
small individual systems are used as reference data for the proposed procedure.
The enhancement of the conductivity in the magnetic domain wall is found in the
present method in accordance with the previous perturbative analysis.Comment: 20 pages, 9 figure
Fibroblast Growth Factor 23 (FGF23) and Disorders of Phosphate Metabolism
Derangements in serum phosphate level result in rickets/osteomalacia or ectopic calcification indicating that healthy people without these abnormalities maintain serum phosphate within certain ranges. These results indicate that there must be a regulatory mechanism of serum phosphate level. Fibroblast growth factor 23 (FGF23) was identified as the last member of FGF family. FGF23 is produced by bone and reduces serum phosphate level by suppressing phosphate reabsorption in proximal tubules and intestinal phosphate absorption through lowering 1,25-dihydroxyvitamin D level. It has been shown that excess and deficient actions of FGF23 result in hypophosphatemic rickets/osteomalacia and hyperphosphatemic tumoral calcinosis, respectively. These results indicate that FGF23 works as a hormone, and several disorders of phosphate metabolism can be viewed as endocrine diseases. It may become possible to treat patients with abnormal phosphate metabolism by pharmacologically modifying the activity of FGF23
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