10,025 research outputs found
Simulating sunflower canopy temperatures to infer root-zone soil water potential
A soil-plant-atmosphere model for sunflower (Helianthus annuus L.), together with clear sky weather data for several days, is used to study the relationship between canopy temperature and root-zone soil water potential. Considering the empirical dependence of stomatal resistance on insolation, air temperature and leaf water potential, a continuity equation for water flux in the soil-plant-atmosphere system is solved for the leaf water potential. The transpirational flux is calculated using Monteith's combination equation, while the canopy temperature is calculated from the energy balance equation. The simulation shows that, at high soil water potentials, canopy temperature is determined primarily by air and dew point temperatures. These results agree with an empirically derived linear regression equation relating canopy-air temperature differential to air vapor pressure deficit. The model predictions of leaf water potential are also in agreement with observations, indicating that measurements of canopy temperature together with a knowledge of air and dew point temperatures can provide a reliable estimate of the root-zone soil water potential
Quantum Cloning, Bell's Inequality and Teleportation
We analyze a possibility of using the two qubit output state from
Buzek-Hillery quantum copying machine (not necessarily universal quantum
cloning machine) as a teleportation channel. We show that there is a range of
values of the machine parameter for which the two qubit output state is
entangled and violates Bell-CHSH inequality and for a different range it
remains entangled but does not violate Bell-CHSH inequality. Further we observe
that for certain values of the machine parameter the two-qubit mixed state can
be used as a teleportation channel. The use of the output state from the
Buzek-Hillery cloning machine as a teleportation channel provides an additional
appeal to the cloning machine and motivation of our present work.Comment: 7 pages and no figures, Accepted in Journal of Physics
Leptonic decay of Heavy-light Mesons in a QCD Potential Model
We study the masses and decay constants of heavy-light flavour mesons D, Ds,
B and Bs in a QCD Potential model. The mesonic wavefunction is used to compute
the masses of D and B mesons in the ground state and the wavefunction is
transformed to momentum space to estimate the pseudoscalar decay constants of
these mesons. The leptonic decay widths and branching ratio of these mesons for
different leptonic channels are also computed to compare with the experimental
values. The results are found to be compatible with available data.Comment: 9 pages,3 table
A common unique fixed point result in metric spaces involving generalised altering distances
In this paper we work out a unique common fixed point result for two self-mappings defined on a complete metric space. These mappings are assumed to satisfy a contractive inequality which involves two generalised altering distances
Probing large distance higher dimensional gravity from lensing data
The modifications induced in the standard weak-lensing formula if Newtonian
gravity differs from inverse square law at large distances are studied. The
possibility of putting bounds on the mass of gravitons from lensing data is
explored. A bound on graviton mass, esitmated to be about 100 Mpc is
obtained from analysis of some recent data on gravitational lensing.Comment: 6 pages, 1 figure, added reference
Unitarity constraints on the stabilized Randall-Sundrum scenario
Recently proposed stabilization mechanism of the Randall-Sundrum metric gives
rise to a scalar radion, which couples universally to matter with a weak
interaction ( TeV) scale. Demanding that gauge boson scattering as
described by the effective low enerrgy theory be unitary upto a given scale
leads to significant constraints on the mass of such a radion.Comment: 10 page Latex 2e file including 4 postscript figures. Accepted in
Journal of Physics
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