First results from KamLAND: evidence for reactor antineutrino disappearance

KamLAND has measured the flux of nu;(e)'s from distant nuclear reactors. We find fewer nu;(e) events than expected from standard assumptions about nu;(e) propagation at the 99.95% C.L. In a 162 ton.yr exposure the ratio of the observed inverse beta-decay events to the expected number without nu;(e) disappearance is 0.611+/-0.085(stat)+/-0.041(syst) for nu;(e) energies >3.4 MeV. In the context of two-flavor neutrino oscillations with CPT invariance, all solutions to the solar neutrino problem except for the "large mixing angle" region are excluded.     

Bounded-degree polyhedronization of point sets

In 1994 Grünbaum showed that, given a point set S in ${\mathbb{R}}^3$, it is always possible to construct a polyhedron whose vertices are exactly S. Such a polyhedron is called a polyhedronization of S. Agarwal et al. extended this work in 2008 by showing that there always exists a polyhedronization that can be decomposed into a union of tetrahedra (tetrahedralizable). In the same work they introduced the notion of a serpentine polyhedronization for which the dual of its tetrahedralization is a chain. In this work we present a randomized algorithm running in $O(n{\log }^{6}n)$ expected time which constructs a serpentine polyhedronization that has vertices with degree at most 7, answering an open question by Agarwal et al.     

Floating Potentials in the Vicinity of Biased Flush‐Mounted Probes

An array of surface‐mounted probe triplets in the Alcator C‐Mod divertor region [1, 2] demonstrates the influence of a biased probe tip on local plasma potential. For the experiments described here, each poloidally aligned triplet contains one probe which measures the local I—V characteristic with a bias sweep and two passive probes which sample the floating potential. The floating potential at the two passive tips varies as a function of the bias at the swept tip. This dependence is shown to vary according to the local plasma parameters. Variations in both the amplitude and width of the floating potential disturbance on electron temperature and density are resolved and compared with different mechanisms of cross field current transport.     

Structure elucidation of an unexpected product from dehydration of a beta-hydroxyketone

The structure of an unexpected compound from the dehydration of an aldol addition product has been determined using 1-D and 2-D NMR techniques. This reaction is the last step in a new synthetic approach to the galanthan ring system. Complete 1H and 13C NMR assignments for two synthetic precursors are also reported.     

THE VECTORIAL PHOTO-EXCITATION IN SOLAR-TRACKING LEAVES OF Lavatera cretica (MALVACEAE)*,†

Abstract— The diaphototropic responses of the solar-tracking leaves of Lavatera cretica were studied under constant levels of vectorial photo-excitation (negligible variations in angle of incidence and fluence rates). The results showed the following:
(a) The photoreceptors, that are associated with the (major) veins, can equally perceive vectorial excitation (by an oblique light-beam in the plane of symmetry of the vein), directed either towards its tip (tip-oriented: TO), or towards its base (base-oriented: BO).
(b) The mechanism of photo-perception is apparently qualitatively the same for TO and BO excitation.
(c) The response to TO and BO vectorial excitation, which takes place in a circular sheath of motor-cell tissue in the pulvinus (a2–3 mm long segment at the top of the petiole), is also highly directional and results in bending in the vertical plane of the oblique beam. Each sector of the motor tissue can expand longitudinally in response to TO excitation, presumably by influx of solutes, and contract longitudinally in response to BO excitation of the same vein, presumably by efflux of solutes.
(d) The angular velocity of the vectorial response to a constant level of vectorial excitation remains constant over large angular displacements and long periods, and was similar for TO and BO over a wide range of fluence rates (30-400 μmol m⁻²s⁻¹) of white light (400-700 nm).
(e) Reversal of the direction of vectorial excitation (TO to BO, and vice versa) results in reversal of the direction of the vectorial response (laminar reorientation). The change in the direction of laminar reorientation involved a larger overshoot in the original direction when the change was from BO to TO, than in the reverse case.