Riemannian theory of Hamiltonian chaos and Lyapunov exponents

This paper deals with the problem of analytically computing the largest Lyapunov exponent for many degrees of freedom Hamiltonian systems. This aim is succesfully reached within a theoretical framework that makes use of a geometrization of newtonian dynamics in the language of Riemannian geometry. A new point of view about the origin of chaos in these systems is obtained independently of homoclinic intersections. Chaos is here related to curvature fluctuations of the manifolds whose geodesics are natural motions and is described by means of Jacobi equation for geodesic spread. Under general conditions ane effective stability equation is derived; an analytic formula for the growth-rate of its solutions is worked out and applied to the Fermi-Pasta-Ulam beta model and to a chain of coupled rotators. An excellent agreement is found the theoretical prediction and the values of the Lyapunov exponent obtained by numerical simulations for both models.Comment: RevTex, 40 pages, 8 PostScript figures, to be published in Phys. Rev. E (scheduled for November 1996

Hemoglobin Yamagata [beta 132(H10)Lys -> Asn; (HBB: c.399A > T)]: a mosaic to be put together

Objectives: Artifactually altered glycated hemoglobin (HbA(1c)) concentrations are frequently linked to hemoglobin (Hb) variants. Their expression and detection require in-depth analysis.Methods: Cation exchange high performance liquid chromatography (HPLC) (Bio-Rad Variant (TM) II; Trinity Biotech Premier Hb9210 Resolution), capillary electrophoresis (CE) (Sebia Capillarys 2 Flex Piercing) and mass spectrometry (MS) (Waters) were used for variant detection; Sanger sequencing, multiplex ligation-dependent probe amplification (MLPA) and next generation sequencing (NGS) were used for DNA analysis; HbA(1c) was measured with cation exchange HPLC (Bio-Rad Variant (TM) II; Arkray Adams HA-8180V; Tosoh HLC-723 G7), CE (Sebia Capillarys 2 Flex Piercing), boronate affinity HPLC (Trinity Biotech Hb9210 Premier), immunoassay (Cobas c501 Tina-quant HbA(1c) Gen. 3; Nihon Kohden CHM-4100 Celltac chemi HbA(1c) HA-411V) and enzymatic assay (Abbott Architect c 8000 HbA(1c)).Results: Hb Yamagata [beta 132(H10)Lys -> Asn; (HBB: c.399A>T)] was identified in the proband by MS after the observation of an abnormal peak in HPLC and CE. A mosaic expression of this variant was detected by NGS (mutant: 8%; wild type: 92%), after negative results in Sanger sequencing. Hb Yamagata interfered with HbA(1c) measurements by cation exchange HPLC and CE whereas immuno and enzymatic assay values showed good agreement with boronate affinity HPLC measurement.Conclusions: A mosaicism of Hb Yamagata was found in a patient with altered HbA(1c) values. This rare gene variant was detected only by advanced technologies as MS and NGS. The variant interfered with common HbA(1c) determination methods.Genetics of disease, diagnosis and treatmen