7,342 research outputs found
New limits on the EC and ECEC processes in Te
New limits on the double beta processes for Te have been obtained
using a 400 cm HPGe detector and a source consisting of natural Te0
powder. At a confidence level of 90% the limits are y for
the EC transition to the ground state, y for the ECEC transition to the first 2 excited
state of Sn (1171.26 keV) and y for
different ECEC() captures to the ground state of Sn.Comment: 9 pages, 4 figures; v2: minor change
Palatini's cousin: A New Variational Principle
A variational principle is suggested within Riemannnian geometry, in which an
auxiliary metric and the Levi Civita connection are varied independently. The
auxiliary metric plays the role of a Lagrange multiplier and introduces
non-minimal coupling of matter to the curvature scalar. The field equations are
2nd order PDEs and easier to handle than those following from the so-called
Palatini method. Moreover, in contrast to the latter method. no gradients of
the matter variables appear. In cosmological modeling, the physics resulting
from the new variational principle will differ from the modeling using the
Palatini method.Comment: 12 page
Roughening and preroughening in the six vertex model with an extended range of interaction
We study the phase diagram of the BCSOS model with an extended interaction
range using transfer matrix techniques, pertaining to the (100) surface of
single component fcc and bcc crystals. The model shows a 2x2 reconstructed
phase and a disordered flat phase. The deconstruction transition between these
phases merges with a Kosterlitz-Thouless line, showing an interplay of Ising
and Gaussian degrees of freedom. As in studies of the fully frustrated XY
model, exponents deviating from Ising are found. We conjecture that
tri-critical Ising behavior may be a possible explanation for the non-Ising
exponents found in those models.Comment: 25 pages in RevTeX 3.0, seven uuencoded postscript figures, REPLACED
because of submission error (figures were not included
Is surface melting a surface phase transition?
Monte Carlo or Molecular Dynamics calculations of surfaces of Lennard-Jones
systems often indicate, apart from a gradual disordering of the surface called
surface melting, the presence of a phase transition at the surface, but cannot
determine the nature of the transition. In the present paper, we provide for a
link between the continuous Lennard-Jones system and a lattice model. We apply
the method for the (001) surface of a Lennard-Jones fcc structure pertaining to
Argon. The corresponding lattice model is a Body Centered Solid on Solid model
with an extended range of interaction, showing in principle rough, flat and
disordered flat phases. We observe that entropy effects considerably lower the
strength of the effective couplings between the atoms. The Argon (001) face is
shown to exhibit a phase transition at T=70.5 +- 0.5 K, and we identify this
transition as roughening. The roughening temperature is in good correspondence
with experimental results for Argon.Comment: 17 pages REVTeX, 14 uuencoded postscript figures appende
Neutron monitors and muon detectors for solar modulation studies: 2. time series
The level of solar modulation at different times (related to the solar
activity) is a central question of solar and galactic cosmic-ray physics. In
the first paper of this series, we have established a correspondence between
the uncertainties on ground-based detectors count rates and the parameter
(modulation level in the force-field approximation) reconstructed from
these count rates. In this second paper, we detail a procedure to obtain a
reference time series from neutron monitor data. We show that we can
have an unbiased and accurate reconstruction (). We also discuss the potential of Bonner spheres spectrometers and muon
detectors to provide time series. Two by-products of this calculation
are updated values for the cosmic-ray database and a web interface to
retrieve and plot from the 50's to today
(\url{http://lpsc.in2p3.fr/crdb}).Comment: 15 pages, 5 figures, 2 tables. AdSR, in press. Web interface to get
modulation parameter phi(t): new tab in http://lpsc.in2p3.fr/crd
TIROS 1- Camera Attitude Data, Analysis of Location Errors, and Derivation of Correction for Calibration
Tiros i, camera attitude data, analysis of location errors, and derivation of correction for calibratio
The effects of diphenamid, trifluralin and EPTC on the control of weeds and the yield and quality of burley and fire-cured tobacco
To produce an acre of either hurley or fire-cured tobacco (Nicotiana tabacum) in Tennessee, 350 to 450 man hours of labor are required. Of the total, 20 to 30 man hours per acre are normally required for cultivations and hoeing (29). The actual time involved depends upon weediness and the relative effectiveness of the cultivation. Often these hoeings and cultivations result in root damage, disease transmission, and leaf injury which may reduce the yield and quality of the cured leaf.
Parris (28) estimated that tobacco growers in Tennessee experience a loss of $1,350,000 annually due to weeds. This loss estimation includes only the cost of weed control in plant beds and the loss of yield in field tobacco. Factors such as loss due to extra land preparation were excluded. This figure could be lowered if more effective and efficient means of weed control could be developed.
Research in the area of chemical weed control on field grown tobacco has been accelerated in an effort to decrease man hours required so as to lower the production cost. This would make it possible for domestic American tobaccos to compete with tobacco grown in other regions of the world on a more equal footing (23). If the per acre production cost could be lowered enough, some corresponding decrease in the gross dollar returns might prove more tolerable to the growers. This can be especially true in instances where disease is a problem and where a minimum of soil and plant contact or translocation may be desired.
The objectives of this study were to determine:
1) by visual ratings the relative effectiveness of three selected herbicides upon the growth of weeds in tobacco;
2) the effects of the herbicides upon the yield and quality of tobacco; and
3) the most effective of the herbicides tested for use in the production of hurley and dark fire-cured tobacco
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