Elasticity, Shape Fluctuations and Phase Transitions in the New Tubule Phase of Anisotropic Tethered Membranes

We study the shape, elasticity and fluctuations of the recently predicted (cond-mat/9510172) and subsequently observed (in numerical simulations) (cond-mat/9705059) tubule phase of anisotropic membranes, as well as the phase transitions into and out of it. This novel phase lies between the previously predicted flat and crumpled phases, both in temperature and in its physical properties: it is crumpled in one direction, and extended in the other. Its shape and elastic properties are characterized by a radius of gyration exponent $\nu$ and an anisotropy exponent $z$. We derive scaling laws for the radius of gyration $R_G(L_\perp,L_y)$ (i.e. the average thickness) of the tubule about a spontaneously selected straight axis and for the tubule undulations $h_{rms}(L_\perp,L_y)$ transverse to its average extension. For phantom (i.e. non-self-avoiding) membranes, we predict $\nu=1/4$, $z=1/2$ and $\eta_\kappa=0$, exactly, in excellent agreement with simulations. For membranes embedded in the space of dimension $d<11$, self-avoidance greatly swells the tubule and suppresses its wild transverse undulations, changing its shape exponents $\nu$ and $z$. We give detailed scaling results for the shape of the tubule of an arbitrary aspect ratio and compute a variety of correlation functions, as well as the anomalous elasticity of the tubules. Finally we present a scaling theory for the shape of the membrane and its specific heat near the continuous transitions into and out of the tubule phase and perform detailed renormalization group calculations for the crumpled-to-tubule transition for phantom membranes.Comment: 34 PRE pages, RevTex and 11 postscript figures, also available at http://lulu.colorado.edu/~radzihov/ version to appear in Phys. Rev. E, 57, 1 (1998); minor change

Rotorcraft technology at Boeing Vertol: Recent advances

An overview is presented of key accomplishments in the rotorcraft development at Boeing Vertol. Projects of particular significance: high speed rotor development and the Model 360 Advanced Technology Helicopter. Areas addressed in the overview are: advanced rotors with reduced noise and vibration, 3-D aerodynamic modeling, flight control and avionics, active control, automated diagnostics and prognostics, composite structures, and drive systems

REGIONAL GAINS AND LOSSES FOR CONSUMERS AND PRODUCERS FROM CHANGES IN FLUID MILK PRICES

Agribusiness,

A collection of edge-based elements

Edge-based elements have proved useful in solving electromagnetic problems since they are nondivergent. Previous authors have presented several two and three dimensional elements. Herein, we present four types of elements which are suitable for modeling several types of three dimensional geometries. Distorted brick and triangular prism elements are given in cartesian coordinates as well as the specialized cylindrical shell and pie-shaped prism elements which are suitable for problems best described in polar cylindrical coordinates

"Soft" Anharmonic Vortex Glass in Ferromagnetic Superconductors

Ferromagnetic order in superconductors can induce a {\em spontaneous} vortex (SV) state. For external field ${\bf H}=0$, rotational symmetry guarantees a vanishing tilt modulus of the SV solid, leading to drastically different behavior than that of a conventional, external-field-induced vortex solid. We show that quenched disorder and anharmonic effects lead to elastic moduli that are wavevector-dependent out to arbitrarily long length scales, and non-Hookean elasticity. The latter implies that for weak external fields $H$, the magnetic induction scales {\em universally} like $B(H)\sim B(0)+ c H^{\alpha}$, with $\alpha\approx 0.72$. For weak disorder, we predict the SV solid is a topologically ordered vortex glass, in the ``columnar elastic glass'' universality class.Comment: minor corrections; version published in PR

On the Complexity of the Single Individual SNP Haplotyping Problem

We present several new results pertaining to haplotyping. These results concern the combinatorial problem of reconstructing haplotypes from incomplete and/or imperfectly sequenced haplotype fragments. We consider the complexity of the problems Minimum Error Correction (MEC) and Longest Haplotype Reconstruction (LHR) for different restrictions on the input data. Specifically, we look at the gapless case, where every row of the input corresponds to a gapless haplotype-fragment, and the 1-gap case, where at most one gap per fragment is allowed. We prove that MEC is APX-hard in the 1-gap case and still NP-hard in the gapless case. In addition, we question earlier claims that MEC is NP-hard even when the input matrix is restricted to being completely binary. Concerning LHR, we show that this problem is NP-hard and APX-hard in the 1-gap case (and thus also in the general case), but is polynomial time solvable in the gapless case.Comment: 26 pages. Related to the WABI2005 paper, "On the Complexity of Several Haplotyping Problems", but with more/different results. This papers has just been submitted to the IEEE/ACM Transactions on Computational Biology and Bioinformatics and we are awaiting a decision on acceptance. It differs from the mid-August version of this paper because here we prove that 1-gap LHR is APX-hard. (In the earlier version of the paper we could prove only that it was NP-hard.

A Paleomagnetic Age Investigation of Pre-Salmon Springs Drift Pleistocene Deposits in the Southern Puget Lowland, Washington

The Pleistocene history of the southern Puget Lowland is marked by repeated invasions by the Puget Lobe of the Cordilleran ice sheet. The present stratigraphic sequence is represented by four glaciations (Orting, Stuck, Salmon Springs, and Fraser) of northern provenance, separated by unconformities and two nonglacial formations (Alderton and Puyallup) of central Cascade and Mount Rainier provenances. Paleomagnetic work conducted on pre-Salmon Springs sediments at their type localities and correlative exposures in the Puyallup Valley provide evidence for the ages of the Orting Drift, Alderton Formation, Stuck Drift, and Puyallup Formation. The silts sampled demonstrate an array of soft (unconsolidated) sediment magnetic behavior. Overprinting is common and is largely attributed to VRM or CRM, yet the sediments do preserve remanent components identified as DRM or PDRM. These primary components are the result of grain alignment during a period of reversed polarity. The successful isolation of reversed remanent directions in the pre-Salmon Springs units leads to a magnetostratigraphic interpretation which restricts the deposition of these sediments to the Matuyama Reverse Epoch