Effects of finite anisotropy parameter Q in the determination of magnetic bubble material parameters

Improved formulas are obtained to provide more accurate determination of magnetic bubble material parameters such as material length(l)and saturation magnetization(M_{s})based on the measurements of domain stripe width and bubble collapse field. The improvement takes into consideration the effects of finite uniaxial anisotropy parameter(Q)in the formulas. These improved formulas are based on the numerical results obtained from micromagnetic domain calculations of periodic stripes and of an isolated axisymmetric bubble.     

Optimal edge ranking of trees in polynomial time

An edge ranking of a graph is a labeling of the edges using positive integers such that all paths between two edges with the same label contain an intermediate edge with a higher label. An edge ranking isoptimal if the highest label used is as small as possible. The edge-ranking problem has applications in scheduling the manufacture of complex multipart products; it is equivalent to finding the minimum height edge-separator tree. In this paper we give the first polynomial-time algorithm to find anoptimal edge ranking of a tree, placing the problem inP. An interesting feature of the algorithm is an unusual greedy procedure that allows us to narrow an exponential search space down to a polynomial search space containing an optimal solution. AnNC algorithm is presented that finds an optimal edge ranking for trees of constant degree. We also prove that a natural decision problem emerging from our sequential algorithm isP-complete.The research of P. de la Torre was partially supported by NSF Grant CCR-9010445. R. Greenlaw's research was partially supported by NSF Grant CCR-9209184. The research of A. A. Schäffer was partially supported by NSF Grant CCR-9010534.Subsequent to the acceptance of this paper, Zhou and Nishizeki found faster algorithms for optimal edge ranking of trees, first reducing the time toO(n²) [22] and then toO(n logn) [23].     

50 Gbit/s low-jitter dynamic decision circuit using Cbc compensation and semi-feed forward techniques

A new low-jitter dynamic decision circuit is designed and fabricated using InP/InGaAs HBTs. Cbc compensation transistors and semi-feed forward loads are adopted to eliminate waveform distortion and residual double trace, respectively. A fabricated decision IC achieves error-free operation and wide eye opening for 50 Gbit/s 2/sup 31/-1 PRBS with 0.68 W power dissipation. Its RMS and peak-to-peak jitter of output data are 0.59 and 4.1 ps, respectively.     

Joan Mason (1923–2004) — Obituary

NTM Zeitschrift für Geschichte der Wissenschaften, Technik und Medizin -     

Molecular characterization of methicillin-resistant Staphylococcus aureus (MRSA) in a university hospital in Italy

The molecular epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in a university hospital in Italy was studied in a five-month period in 1996, during which all S. aureus isolated were collected. All MRSA isolates (95) and a sample of methicillin-susceptible S. aureus (20) were typed with a variety of phenotypic and genotypic methods. Clonal identities were determined by pulsed-field gel electrophoresis (PFGE) of chromosomal SmaI digests and, for MRSA isolates, by probing ClaI digests with a mecA probe and a Tn554 probe. Overall, MRSA represented 32.3% of all isolates, with very high percentages from the intensive care units (adult and neonatal). PFGE after restriction with SmaI resolved genomic DNA of 95 MRSA strains into 26 major PFGE patterns. The use of southern blot hybridization of ClaI genomic digests with mecA and Tn554 allowed us a significant increase in discrimination, differentiating at least 32 different clones. Two major clones, however, each sharing common ClaI-mecA and Tn554 type and PFGE pattern as well as a common resistance phenotype, represented more than 50% of all MRSA isolates. The recovery of these two clones in the majority of the isolates of adult and neonatal intensive care units, respectively, is indicative of typical nosocomial outbreaks and clonal spread. It is concluded that intensive care units are major areas requiring preventative interventions.     

Adsorption thermodynamics and diffusion of disperse anthraquinone dyes in acetate fibre

Diffusion coefficients, thermodynamic parameters and adsorption equilibrium isotherms of some anthraquinone dyes for acetate fibre are reported. The chemical constitution seems to be more important than the size factor in determining dye diffusion into the interior of the fibres. The activation energies of diffusion decreased strongly when o-dichlorobenzene was present, due to the plasticising effect of carrier. Nernst partition isotherms were obtained, up to saturation. Substantivity decreased when water-solubilising groups are present in the molecule.The aqueous solubilities and heats of solution have been measured; the higher ΔH_w values were found for the derivatives which can form intermolecular hydrogen bonding in the crystalline state.     

Beneficial effects of Helicobacter pylori eradication on migraine

BACKGROUND/AIMS: Migraine is a commonly unilateral throbbing headache, which has been associated with disorders of the vascular tone. Helicobacter pylori, the most relevant cause of gastritis and peptic ulcer, has been recently associated with a typical functional vascular disorder such as primary Raynaud phenomenon. The aim of this study was to assess the prevalence of H. pylori for patients affected by migraine and the effects of H. pylori eradication on migraine symptoms. METHODOLOGY: Two-hundred and twenty-five patients were consecutively enrolled between October 1996 and January 1997. H. pylori was assessed by 13C-urea breath test. Infected subjects were eradicated of the bacterium; frequency, intensity and duration of attacks of migraine were assessed during a 6 month follow-up period. RESULTS: H. pylori was detected in 40% of the patients. Eighty-three percent of the patients who underwent therapy were eradicated. Intensity, duration and frequency of attacks of migraine were significantly reduced in all eradicated patients. CONCLUSIONS: H. pylori is common in subjects with migraine. Bacterium eradication causes a significant decrease in attacks of migraine. The reduction of vasoactive substances produced during infection may be the pathogenetic mechanism underlying the phenomenon.