2,351 research outputs found
Issues and Concerns in Implementing Quality Circles in Public School Management in Nigeria
Quality improvement in educational institutions in Nigeria and the world at large is a major concern. Countries all over the world are therefore making concerted efforts towards the improvement of educational standards. One of the management techniques applied in most of these countries especially Japan, Britain and America is the Quality Control circles. Its application in Nigeria raises a lot of concerns. These concerns and issues bother on the structure, techniques; methods; and reactions of management of the institutions in implementing the recommendations of quality circles. These and many other issues and concerns form the major crux of this paper. The paper concludes that inspite of these issues and concerns; Quality circle is a technique that will assist in the achievement of educational goals Keywords: Issues and concerns, Implementing, Public Schools and Management
CP Violation and Dark Matter
A brief review is given of the effects of CP violation on the direct
detection of neutralinos in dark matter detectors. We first summarize the
current developments using the cancellation mechanism which allows for the
existence of large CP violating phases consistent with experimental limits on
the electron and on the neutron electric dipole moments in a broad class of
SUSY, string and D brane models. We then discuss their effects on the
scattering of neutralinos from quarks and on the event rates. It is found that
while CP effects on the event rates can be enormous such effects are reduced
significantly with the imposition of the EDM constraints. However, even with
the inclusion of the EDM constraints the effects are still very significant and
should be included in a precision prediction of event rates in any SUSY, string
or D brane model.Comment: Based on an invited talk at the conference "Sources and Detection of
Dark Matter in the Universe", at Marina del Rey, CA, Feb. 23-25, 2000; 12
pages, Latex including 2 figure
Slepton Flavor Nonuniversality, the Muon EDM and its Proposed sensitive Search at Brookhaven
We analyze the electric dipole moment of the electron (), of the neutron
() and of the muon () using the cancellation mechanism in the
presence of nonuniversalities of the soft breaking parameters. It is shown that
the nonuniversalities in the slepton sector produce a strong violation of the
scaling relation in the cancellation region. An
analysis of and under the constraints of the current
experimental limits on and and under the constraints of the recent
Brookhaven result on shows that in the non-scaling region
can be as large as ()ecm and thus within reach of the
recently proposed Brookhaven experiment for a sensitive search for at
the level of ecm.Comment: 24 pages, Latex, including 5 figures with additional reference
Electromagnetic Couplings of Nucleon Resonances
An effective Lagrangian calculation of pion photoproduction including all
nucleon resonances up to GeV is presented. We compare our
results to recent calculations and show the influence of different width
parametrizations and offshell cutoffs on the photoproduction multipoles. We
determine the electromagnetic couplings of the resonances from a new fit to the
multipole data.Comment: 20 pages, latex, 6 figures. Misprints corrected, text & 3 figures
adde
Singlet ground state in the alternating spin- chain compound NaVOAsO
We present the synthesis and a detailed investigation of structural and
magnetic properties of polycrystalline NaVOAsO by means of x-ray
diffraction, magnetization, electron spin resonance (ESR), and As
nuclear magnetic resonance (NMR) measurements as well as density-functional
band structure calculations. Temperature-dependent magnetic susceptibility, ESR
intensity, and NMR line shift could be described well using an alternating
spin- chain model with the exchange coupling K and
an alternation parameter . From the high-field magnetic
isotherm measured at K, the critical field of the gap closing is found
to be T, which corresponds to the zero-field spin gap of
K. Both NMR shift and spin-lattice relaxation
rate show an activated behavior at low temperatures, further confirming the
singlet ground state. The spin chains do not coincide with the structural
chains, whereas the couplings between the spin chains are frustrated. Because
of a relatively small spin gap, NaVOAsO is a promising compound for further
experimental studies under high magnetic fields.Comment: 14 pages, 10 figures, 2 table
Raman anomalies as signatures of pressure induced electronic topological and structural transitions in black phosphorus: Experiments and Theory
We report high pressure Raman experiments of Black phosphorus up to 24 GPa.
The line widths of first order Raman modes A, B and A of the
orthorhombic phase show a minimum at 1.1 GPa. Our first-principles density
functional analysis reveals that this is associated with the anomalies in
electron-phonon coupling at the semiconductor to topological insulator
transition through inversion of valence and conduction bands marking a change
from trivial to nontrivial electronic topology. The frequencies of B and
A modes become anomalous in the rhombohedral phase at 7.4 GPa, and new
modes appearing in the rhombohedral phase show anomalous softening with
pressure. This is shown to originate from unusual structural evolution of black
phosphorous with pressure, based on first-principles theoretical analysis.Comment: 13pages, 12figure
Electron-Hole Asymmetry in the Electron-phonon Coupling in Top-gated Phosphorene Transistor
Using in-situ Raman scattering from phosphorene channel in an
electrochemically top-gated field effect transistor, we show that its phonons
with A symmetry depend much more strongly on concentration of electrons
than that of holes, while the phonons with B symmetry are insensitive to
doping. With first-principles theoretical analysis, we show that the observed
electon-hole asymmetry arises from the radically different constitution of its
conduction and valence bands involving and bonding states
respectively, whose symmetry permits coupling with only the phonons that
preserve the lattice symmetry. Thus, Raman spectroscopy is a non-invasive tool
for measuring electron concentration in phosphorene-based nanoelectronic
devices
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