17,258 research outputs found
Small Area Shrinkage Estimation
The need for small area estimates is increasingly felt in both the public and
private sectors in order to formulate their strategic plans. It is now widely
recognized that direct small area survey estimates are highly unreliable owing
to large standard errors and coefficients of variation. The reason behind this
is that a survey is usually designed to achieve a specified level of accuracy
at a higher level of geography than that of small areas. Lack of additional
resources makes it almost imperative to use the same data to produce small area
estimates. For example, if a survey is designed to estimate per capita income
for a state, the same survey data need to be used to produce similar estimates
for counties, subcounties and census divisions within that state. Thus, by
necessity, small area estimation needs explicit, or at least implicit, use of
models to link these areas. Improved small area estimates are found by
"borrowing strength" from similar neighboring areas.Comment: Published in at http://dx.doi.org/10.1214/11-STS374 the Statistical
Science (http://www.imstat.org/sts/) by the Institute of Mathematical
Statistics (http://www.imstat.org
Quasi-Inclusive and Exclusive decays of to
We consider the effective Hamiltonian of four quark operators in the Standard
Model in the exclusive and quasi-inclusive decays of the type , , where contains a single Kaon. Working
in the factorization assumption we find that the four quark operators can
account for the recently measured exclusive decays
and for appropriate choice of form factors but cannot explain the
large quasi-inclusive rate.Comment: Calculation of added and the correct BSW form factors
have been used. Latex 13 papges, 1 figur
One-shot rates for entanglement manipulation under non-entangling maps
We obtain expressions for the optimal rates of one- shot entanglement
manipulation under operations which generate a negligible amount of
entanglement. As the optimal rates for entanglement distillation and dilution
in this paradigm, we obtain the max- and min-relative entropies of
entanglement, the two logarithmic robustnesses of entanglement, and smoothed
versions thereof. This gives a new operational meaning to these entanglement
measures. Moreover, by considering the limit of many identical copies of the
shared entangled state, we partially recover the recently found reversibility
of entanglement manipu- lation under the class of operations which
asymptotically do not generate entanglement.Comment: 7 pages; no figure
Nonlinear conductance quantization in graphene ribbons
We present numerical studies of non-linear conduction in graphene nanoribbons
when a bias potential is applied between the source and drain electrodes. We
find that the conductance quantization plateaus show asymmetry between the
electron and hole branches if the potential in the ribbon equals the source or
drain electrode potential and strong electron (hole) scattering occurs. The
scattering may be at the ends of a uniform ballistic ribbon connecting wider
regions of graphene or may be due to defects in the ribbon. We argue that, in
ribbons with strong defect scattering, the ribbon potential is pinned to that
of the drain (source) for electron (hole) transport. In this case symmetry
between electron and hole transport is restored and our calculations explain
the upward shift of the conductance plateaus with increasing bias that was
observed experimentally by Lin et al. [Phys. Rev. B 78, 161409 (2008)].Comment: 6 pages, 3 figure
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