Robin Hartshorne

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We study in detail locally Cohen-Macaulay curves in P 3 which are contained in a double plane 2H, thus completing the classification of curves lying on surfaces of degree two. We describe the irreducible components of the Hilbert schemes H d,g (2H) of locally Cohen-Macaulay curves in 2H of degree d and arithmetic genus g, and we show that H d,g (2H) is(More)
We study Gorenstein liaison of codimension two subschemes of an arithmetically Gorenstein scheme X. Our main result is a criterion for two such subschemes to be in the same Gorenstein liaison class, in terms of the category of ACM sheaves on X. As a consequence we obtain a criterion for X to have the property that every codimension 2 arithmetically(More)
The ion conduction and voltage dependence of sodium channels purified from rat brain were investigated in planar lipid bilayers in the presence of batrachotoxin. Single channel currents are clearly resolved. Channel opening is voltage dependent and favored by depolarization. The voltage at which the channel is open 50% of the time is -91 +/- 17 mV (SD, n =(More)
Single channel currents of sodium channels purified from rat brain and reconstituted into planar lipid bilayers were recorded. The kinetics of channel gating were investigated in the presence of batrachotoxin to eliminate inactivation and an analysis was conducted on membranes with a single active channel at any given time. Channel opening is favored by(More)
We study the lowest dimensional open case of the question whether every arithmetically Cohen–Macaulay subscheme of P N is glicci, that is, whether every zero-scheme in P 3 is glicci. We show that a general set of n ≥ 56 points in P 3 admits no strictly descending Gorenstein liaison or biliaison. In order to prove this theorem, we establish a number of(More)
We characterize the postulation character of arithmetically Gorenstein curves in P 4. We give conditions under which the curve can be realized in the form mH − K on some ACM surface. Finally, we strengthen a theorem of Watanabe by showing that any general arithmetically Gorenstein curve in P 4 can be obtained from a line by a series of ascending(More)
A voltage-sensitive K+ channel previously cloned from rat heart designated RK5 (rat Kv4.2) (Roberds and Tamkun, 1991, Proc. Natl. Acad. Sci. USA 88, 1798-1802) was functionally characterized in the Xenopus oocyte expression system. RK5 is a homolog of the Drosophila Shal K+ channel, activates with a rise time of 2.8 ms, has a midpoint for activation of -1(More)