Ivan C. Smith

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We introduce a symplectic surgery in six dimensions which collapses Lagrangian three-spheres and replaces them by symplectic two-spheres. Under mirror symmetry it corresponds to an operation on complex 3-folds studied by Clemens, Friedman and Tian. We describe several examples which show that there are either many more Calabi-Yau manifolds (e.g., rigid(More)
The application of 13-C nuclear magnetic resonance to the analysis of some sialic acid-containing meningococcal polysaccharide antigens is described. Complete assignments of the spectra of both the native serogroup B and the de-O-acetylated serogroup C polysaccharides have been made. These assignments were based on the corresponding data for some related(More)
We have previously detected a paralytic factor in gel filtration-separated venom from the endoparasitoid wasp Pimpla hypochondriaca which is active against the fly Musca domestica. Now we have further purified this factor, which we have called pimplin, by reverse phase chromatography, and established using SDS-PAGE that it has a molecular mass of(More)
The main metabolic pathways in Methanospirillum hungatei GP1 were followed by using 13C nuclear magnetic resonance, with 13C-labeled acetate and CO2 as carbon sources. The labeling patterns found in carbohydrates, amino acids, lipids, and nucleosides were consistent with the formation of pyruvate from acetate and CO2 as the first step in biosynthesis.(More)
Isolinoleic acid (18:2 delta 6,9) deuterated at 10 different positions was esterified to form 1-palmitoyl-2-isolinoleoyl-sn-glycero-3-phosphocholine (PiLPC), and the average structural and motional properties of the diunsaturated chain, in aqueous dispersions of PiLPC, were examined by 2H NMR spectroscopy. For each sample, 2H spectra were acquired over a(More)
We present a new proof of a result due to Taubes: if (X,ω) is a closed symplectic four-manifold with b+(X) > 1 + b1(X) and λ[ω] ∈ H (X;Q) for some λ ∈ R, then the Poincaré dual of KX may be represented by an embedded symplectic submanifold. The result builds on the existence of Lefschetz pencils on symplectic four-manifolds. We approach the topological(More)
According to Taubes, the Gromov invariants of a symplectic four-manifold X with b+ > 1 satisfy the duality Gr(α) = ±Gr(κ−α), where κ is Poincaré dual to the canonical class. Extending joint work with Simon Donaldson, we interpret this result in terms of Serre duality on the fibres of a Lefschetz pencil on X, by proving an analogous symmetry for invariants(More)