16,470 research outputs found
Role of Insects and Diseases in a Jack Pine Provenance Study
Two jack pine plantations were established at the Cloquet Forestry Center, Cloquet, Minnesota, in 1942 and 1943, using trees originating from 22 sites in the United States and 10 in Canada. From 1945 to 1953 the incidence of attack by insects and diseases was recorded individually for all trees, and in 1980-1981 the diameter and form of both living and dead trees were recorded. There were differences in the incidence of attack by the pests and in tree response to early injury among the various seed sources. In 1980 and in 1981 there were differences in tree form resulting from insect and both living and dead pest-free trees had the best form. The diameter increases from 1955 to 1980-1981 were almost identical for all categories with the exception of the dead pest-free trees which had the smallest diameters
Building application of solar energy. Study no. 4: Scenarios for the utilization of solar energy in southern California buildings, change 1
Plausible future market scenarios for solar heating and cooling systems into buildings in the area served by the Southern California Edison Company. A range of plausible estimates for the number of solar systems which might be installed and the electrical energy which might be displaced by energy from these systems are provided. The effect on peak electrical load was not explicitly calculated but preliminary conclusions concerning peak load can be inferred from the estimates presented. Two markets are investigated: the single family market and the large power commercial market
Clinical, histological and prognostic features of a novel nail-bed lesion of cats: 41 cases
There is a distinct subset of lesions arising on the digits of cats, located at or close to the nail-bed epithelium, which are typically composed of proliferative fibroblast-like cells, multinucleate giant cells and areas of osseous metaplasia, but currently there is no published literature detailing the clinical or histological features of these lesions. This study identified 41 such cases from two large commercial diagnostic laboratories and assessed various histological and clinical features; 22 cases had additional follow-up data available
Some Remarks about Variable Mass Systems
We comment about the general argument given to obtain the rocket equation as
it is exposed in standard textbooks. In our opinion, it can induce students to
a wrong answer when solving variable mass problems.Comment: 2 page
Loschmidt echoes in two-body random matrix ensembles
Fidelity decay is studied for quantum many-body systems with a dominant
independent particle Hamiltonian resulting e.g. from a mean field theory with a
weak two-body interaction. The diagonal terms of the interaction are included
in the unperturbed Hamiltonian, while the off-diagonal terms constitute the
perturbation that distorts the echo. We give the linear response solution for
this problem in a random matrix framework. While the ensemble average shows no
surprising behavior, we find that the typical ensemble member as represented by
the median displays a very slow fidelity decay known as ``freeze''. Numerical
calculations confirm this result and show, that the ground state even on
average displays the freeze. This may contribute to explanation of the
``unreasonable'' success of mean field theories.Comment: 9 pages, 5 figures (6 eps files), RevTex; v2: slight modifications
following referees' suggestion
A procedure to analyze nonlinear density waves in Saturn's rings using several occultation profiles
Cassini radio science experiments have provided multiple occultation optical
depth profiles of Saturn's rings that can be used in combination to analyze
density waves. This paper establishes an accurate procedure of inversion of the
wave profiles to reconstruct the wave kinematic parameters as a function of
semi-major axis, in the nonlinear regime. This procedure is achieved from
simulated data in the presence of realistic noise perturbations, to control the
reconstruction error. By way of illustration we have applied our procedure to
the Mimas 5:3 density wave. We were able to recover precisely the kinematic
parameters from the radio experiment occultation data in most of the
propagation region; a preliminary analysis of the pressure-corrected dispersion
allowed us to determine new but still uncertain values for the opacity
( cm/g) and velocity dispersion of ( cm/s) in
the wave region. Our procedure constitutes the first step in our planned
analysis of the density waves of Saturn's rings. It is very accurate and
efficient in the far-wave region. However, improvements are required within the
first wavelength. The ways in which this method can be used to establish
diagnostics of ring physics are outlined.Comment: 50 pages,13 figures, 2 tables. Published in Icarus
Finite-element nonlinear transient response computer programs PLATE 1 and CIVM-PLATE 1 for the analysis of panels subjected to impulse or impact loads
Two computer programs are described for predicting the transient large deflection elastic viscoplastic responses of thin single layer, initially flat unstiffened or integrally stiffened, Kirchhoff-Lov ductile metal panels. The PLATE 1 program pertains to structural responses produced by prescribed externally applied transient loading or prescribed initial velocity distributions. The collision imparted velocity method PLATE 1 program concerns structural responses produced by impact of an idealized nondeformable fragment. Finite elements are used to represent the structure in both programs. Strain hardening and strain rate effects of initially isotropic material are considered
On the dominance of J(P)=0(+) ground states in even-even nuclei from random two-body interactions
Recent calculations using random two-body interactions showed a preponderance
of J(P)=0(+) ground states, despite the fact that there is no strong pairing
character in the force. We carry out an analysis of a system of identical
particles occupying orbits with j=1/2, 3/2 and 5/2 and discuss some general
features of the spectra derived from random two-body interactions. We show that
for random two-body interactions that are not time-reversal invariant the
dominance of 0(+) states in this case is more pronounced, indicating that
time-reversal invariance cannot be the origin of the 0(+) dominance.Comment: 8 pages, 3 tables and 3 figures. Phys. Rev. C, in pres
1/f noise in the Two-Body Random Ensemble
We show that the spectral fluctuations of the Two-Body Random Ensemble (TBRE)
exhibit 1/f noise. This result supports a recent conjecture stating that
chaotic quantum systems are characterized by 1/f noise in their energy level
fluctuations. After suitable individual averaging, we also study the
distribution of the exponent \alpha in the 1/f^{\alpha} noise for the
individual members of the ensemble. Almost all the exponents lie inside a
narrow interval around \alpha=1 suggesting that also individual members exhibit
1/f noise, provided they are individually unfoldedComment: 4 pages, 3 figures, Accepted for publication in Phys. Rev.
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