3,711 research outputs found
Final report of the Committee on Depreciation; Dissenting opinion to the final report of the Committee on Depreciation
Losses of value which are complete, and fully demonstrated by proper abandonment or necessary replacement of the whole or a unit part of a property, are a matter of history and fact, and require only proper accounting to determine their occurrence and amount. Losses of value, which are partial or incomplete, always require prophecy as to future need, usefulness, and service, in order to properly divide that portion of the value which still exists from that which is lost. This function necessitates much more judgment than accounting. It requires the careful analysis of a broadly trained, experienced, and practical mind, thoroughly familiar with the business in question. Original item in Boxno. 0409
Crown and root rots of table grapes caused by Phytophthora spp. in Chile
Phytophthora crown and root rot of grapevine (Vitis vinifera L.) occurs frequently in Chile, where grapes are cultivated on their own roots. P. cinnamomi, P. cryptogea, and P. drechsleri were isolated from diseased root or crown tissue of the table grape cvs Flame Seedless, Italia, Red Globe, and Thompson Seedless with P. cryptogea being the most frequently isolated species. These pathogens were identified on the basis of standard morphological and cultural features and were compared by SDS-PAGE profiles of mycelial proteins. All isolates were pathogenic on 1-year-old cane segments and 1-year-old rooted grapevines of cvs Thompson Seedless and Red Globe. The latter cultivar was more susceptible than Thompson Seedless. P. cinnamomi and P. cryptogea have been associated with root rot of grapevines elsewhere, but this is the first report of P. drechsleri as a pathogen of grapevines and the first report of Phytophthora spp. affecting table grapes in Chile
Gluelump Spectrum in the Bag Model
We explore the ordering of the lowest levels in a simple bag model of the
``gluelump'' of Michael and also discuss, again within the context of the bag
model, the related problem of hybrid potentials in the limit of very small
spacing between quark and anti-quark sources.Comment: 10 page
Development of a chromium-thoria alloy
Low temperature ductility and high temperature strength of pure chromium and chromium-thoria alloy prepared from vapor deposited powder
Cool Companions to White Dwarfs from the 2MASS Second Incremental Data Release
We present near-infrared magnitudes for all white dwarfs (selected from the
catalog of McCook & Sion) contained in the 2 Micron All Sky Survey Second
Incremental Data Release(2MASS 2IDR). We show that the near-IR color-color
diagram is an effective means of identifying candidate binary stars containing
a WD and a low mass main sequence star. The loci of single WDs and WD + red
dwarf binaries occupy distinct regions of the near-IR color-color diagram. We
recovered all known unresolved WD + red dwarf binaries located in the 2IDR sky
coverage, and also identified as many new candidate binaries (47 new candidates
out of 95 total). Using observational near-IR data for WDs and M-L dwarfs, we
have compared a sample of simulated WD + red dwarf binaries with our 2MASS
data. The colors of the simulated binaries are dominated by the low mass
companion through the late-M to early-L spectral types. As the spectral type of
the companion becomes progressively later, however, the colors of unresolved
binaries become progressively bluer. Binaries containing the lowest mass
companions will be difficult to distinguish from single WDs solely on the basis
of their near-IR colors.Comment: 18 pages, including 2 figures, accepted for publication in Ap
Correlation length scalings in fusion edge plasma turbulence computations
The effect of changes in plasma parameters, that are characteristic near or
at an L-H transition in fusion edge plasmas, on fluctuation correlation lengths
are analysed by means of drift-Alfven turbulence computations. Scalings by
density gradient length, collisionality, plasma beta, and by an imposed shear
flow are considered. It is found that strongly sheared flows lead to the
appearence of long-range correlations in electrostatic potential fluctuations
parallel and perpendicular to the magnetic field.Comment: Submitted to "Plasma Physics and Controlled Fusion
Nucleon Axial Form Factor from Lattice QCD
Results for the isovector axial form factors of the proton from a lattice QCD
calculation are presented for both point-split and local currents. They are
obtained on a quenched lattice at with Wilson
fermions for a range of quark masses from strange to charm. We determine the
finite lattice renormalization for both the local and point-split currents of
heavy quarks. Results extrapolated to the chiral limit show that the
dependence of the axial form factor agrees reasonably well with experiment. The
axial coupling constant calculated for the local and the point-split
currents is about 6\% and 12\% smaller than the experimental value
respectively.Comment: 8 pages, 5 figures (included in part 2), UK/93-0
Solvable three-state model of a driven double-well potential and coherent destruction of tunneling
A simple model for a particle in a double well is derived from discretizing its configuration space. The model contains as many free parameters as the original system and it respects all the existing symmetries. In the presence of an external periodic force both the continuous system and the discrete model are shown to possess a generalized time-reversal symmetry in addition to the known generalized parity. The impact of the driving force on the spectrum of the Floquet operator is studied. In particular, the occurrence of degenerate quasienergies causing coherent destruction of tunneling is discussed—to a large extent analytically—for arbitrary driving frequencies and barrier heights
Mixing of scalar glueballs and flavour-singlet scalar mesons
We discuss in detail the extraction of hadronic mixing strengths from lattice
studies. We apply this to the mixing of a scalar glueball and a scalar meson in
the quenched approximation. We also measure correlations appropriate for
flavour-singlet scalar mesons using dynamical quark configurations from UKQCD.
This enables us to compare the results from the quenched study of the mixing
with the direct determination of the mixed spectrum. Improved methods of
evaluating the disconnected quark diagrams are also presented.Comment: 23 pages, 5 postscript figure
- …