1H, 13C and 15N NMR spectra of ciprofloxacin

1H NMR assignment, including the values of delta(H) and J(H,H) for the cyclopropane moiety, and 13C NMR and 15N NMR spectral data for ciprofloxacin are presented.     

Cohen-Macaulay Properties of Thom-Boardman Strata II: The Defining Ideals of {Sigma}i, j

We consider the Zariski closure of Thom–Boardman strata^{i, j} in the jet space for map-germs (Cⁿ, 0) (C^p, 0). We applythe geometric technique of calculating syzygies to the desingularizationof ^{i, j} constructed by Ronga. We investigate when the normalizationof the coordinate ring of ^{i, j} is rational in the cases i =n – p + 1 or i = j = 1. We also consider when these coordinaterings are normal with rational singularities. 2000 MathematicsSubject Classification 13D02, 14B05, 14M05, 14M12, 58C25 (primary),58K20 (secondary).     

Differences in Channelling of H0 and H+ in Si Single Crystal

The differences in the RBS angular yields measured for 100 keV hydrogen atoms H⁰ and protons H⁺ backscattered from Si crystal are reported and analysed. It was shown that H⁰ atom beam is better channelled in the pure crystal and is much more sensitive to the crystal surface coverage, particularly, Au layer than the H⁺ ion beam. The deep crystal regions seem to strengthen this differences.     

From noncommutative κ-Minkowski to Minkowski space–time

We show that free κ-Minkowski space field theory, discussed in the context of κ-Poincaré algebra and Doubly Special Relativity is equivalent to a relativistically invariant free field theory on Minkowski space–time. The field theory we obtain has in spectrum a relativistic mode of arbitrary mass m and a Planck mass tachyon. We show that while the energy–momentum for the relativistic mode is essentially the standard one, it diverges for the tachyon, so that there are no asymptotic tachyonic states in the theory. It also follows that the dispersion relation is not modified, so that, in particular, in this theory the speed of light is energy-independent.     

Inheriting independence and chi-squaredness under certain matrix orderings

Let x ～ N(μ, Z), and let S = (Σ:μ). It is shown that if x′A₁x is independent of x′Bx (x′A₁x is distributed as a chi-square variable), then this property is inherited by every x′A₂x for which S′A₂S precedes S′A₁S with respect to the range preordering (with respect to the rank subtractivity partial ordering).     

The cyanide-catalyzed conversion of β-formylmuconates into triglochinates: A useful biomimetic synthesis

Upon treatment with cyanide under slightly basic conditions, β-formyl-cis,cis-muconic acid and esters, prepared from vanillin, undergo a sequence of prototropic shifts equivalent to an internal redox process in which 1,4-reduction of the diene system is blanaced by oxidation of the formyl group.