5,552 research outputs found
Chromium uptake by Fenugreek
Fenugreek (Trigonella foenum- graecum) is both herb (leaves) and a spice (seed) belonging to the family Fabaceae. Fenugreek leaves and seeds are used in the cuisine of India. Fenugreek also has medicinal value. Fenugreek seeds are known to reduce serum glucose and improve glucose tolerance and hence are prescribed to diabetic patients. In the recent past supplemental Chromium is being prescribed to diabetic patients to activate (increased- insulin binding, insulin receptor number, insulin receptor phosphorylation) insulin. Plants can uptake substantial quantities of toxic metals from contaminated soils if these soils are well ameliorated. 

It is then probable that the medicinal efficacy of Fenugreek in the case of diabetes could be enhanced if it takes up chromium from the soil. Preliminary studies are being conducted to note the chromium uptake by Fenugreek from soils which are applied with potassium dichromate
Studies on the Accumulation of Chromium in Fenugreek
Studying Cr uptake by Fenugreek, we note that the maximum concentration of Cr takes place in the shells of the pods followed by leaves, stems and seeds in that order. Interestingly, applied higher doses of Cr does not increase accumulation of Cr in the stems, rather Cr content in the stems levels off. However, the maximum dispersal/distribution of Cr taken up is in the leaves
Models at a Lifshitz Point
We consider models in dimensions around Lifshitz fixed
points with dynamical critical exponent , in the large-N expansion. It is
shown that these models are asymptotically free and dynamically generate a mass
for the fields for all . We demonstrate that, for , the
initially nondynamical gauge field acquires kinetic terms in a way similar to
usual models in 1+1 dimensions. Lorentz invariance emerges
generically in the low-energy electrodynamics, with a nontrivial dielectric
constant given by the inverse mass gap and a magnetic permeability which has a
logarithmic dependence on scale. At a special multicritical point, the
low-energy electrodynamics also has , and an essentially singular
dependence of the effective action on .Comment: LaTeX 13 pages; added a comment about constant field effective
action. version published in Physical Review
Exclusion statistics: A resolution of the problem of negative weights
We give a formulation of the single particle occupation probabilities for a
system of identical particles obeying fractional exclusion statistics of
Haldane. We first derive a set of constraints using an exactly solvable model
which describes an ideal exclusion statistics system and deduce the general
counting rules for occupancy of states obeyed by these particles. We show that
the problem of negative probabilities may be avoided with these new counting
rules.Comment: REVTEX 3.0, 14 page
On supersymmetry breaking in string theory from gauge theory in a throat
We embed the supersymmetry breaking mechanism in N=1 SQCD of hep-th/0602239
in a smooth superstring theory using D-branes in the background R^4 \times
SL(2)_{k=1}/U(1) which smoothly captures the throat region of an intersecting
NS5-brane configuration. A controllable deformation of the supersymmetric
branes gives rise to the mass deformation of the magnetic SQCD theory on the
branes. The consequent instability on the open string worldsheet can be
followed onto a stable non-supersymmetric configuration of D-branes which
realize the metastable vacuum configuration in the field theory. The new brane
configuration is shown to backreact onto the background such as to produce
different boundary conditions for the string fields in the radial direction
compared to the supersymmetric configuration. In the string theory, this is
interpreted to mean that the supersymmetry breaking is explicit rather than
spontaneous.Comment: 29 pages, harvmac, 8 figures; v2 typos corrected, reference adde
Finite Temperature Magnetism in Fractional Quantum Hall Systems: Composite Fermion Hartree-Fock and Beyond
Using the Hamiltonian formulation of Composite Fermions developed recently,
the temperature dependence of the spin polarization is computed for the
translationally invariant fractional quantum Hall states at and
in two steps. In the first step, the effect of particle-hole
excitations on the spin polarization is computed in a Composite Fermion
Hartree-Fock approximation. The computed magnetization for lies above
the experimental results for intermediate temperatures indicating the
importance of long wavelength spin fluctuations which are not correctly treated
in Hartree-Fock. In the second step, spin fluctuations beyond Hartree-Fock are
included for by mapping the problem on to the coarse-grained
continuum quantum ferromagnet. The parameters of the effective continuum
quantum ferromagnet description are extracted from the preceding Hartree-Fock
analysis. After the inclusion of spin fluctuations in a large-N approach, the
results for the finite-temperature spin polarization are in quite good
agreement with the experiments.Comment: 10 pages, 8 eps figures. Two references adde
Spin-excitations of the quantum Hall ferromagnet of composite fermions
The spin-excitations of a fractional quantum Hall system are evaluated within
a bosonization approach. In a first step, we generalize Murthy and Shankar's
Hamiltonian theory of the fractional quantum Hall effect to the case of
composite fermions with an extra discrete degree of freedom. Here, we mainly
investigate the spin degrees of freedom, but the proposed formalism may be
useful also in the study of bilayer quantum-Hall systems, where the layer index
may formally be treated as an isospin. In a second step, we apply a
bosonization scheme, recently developed for the study of the two-dimensional
electron gas, to the interacting composite-fermion Hamiltonian. The dispersion
of the bosons, which represent quasiparticle-quasihole excitations, is
analytically evaluated for fractional quantum Hall systems at \nu = 1/3 and \nu
= 1/5. The finite width of the two-dimensional electron gas is also taken into
account explicitly. In addition, we consider the interacting bosonic model and
calculate the lowest-energy state for two bosons. Besides a continuum
describing scattering states, we find a bound-state of two bosons. This state
is interpreted as a pair excitation, which consists of a skyrmion of composite
fermions and an antiskyrmion of composite fermions. The dispersion relation of
the two-boson state is evaluated for \nu = 1/3 and \nu = 1/5. Finally, we show
that our theory provides the microscopic basis for a phenomenological
non-linear sigma-model for studying the skyrmion of composite fermions.Comment: Revised version, 14 pages, 4 figures, accepted to Phys. Rev.
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