48,150 research outputs found
Integrated lake farming for fish and environmental management in large shallow Chinese lakes: a review
Large shallow lakes in the Pacific Drainage Basin of China are unique aquatic natural resources intensively exploited in recent years for integrated lake farming. This paper presents a general description and major components of this culture method and discusses potential concerns and effects of increased fishery production on aquatic environments.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72470/1/j.1365-2109.1989.tb00371.x.pd
Inclusive Decays of Bottom Hadrons in New Formulation of Heavy Quark Effective Field Theory
We apply the new formulation of heavy quark effective field theory (HQEFT) to
the inclusive decays of bottom hadrons. The long-term ambiguity of using heavy
quark mass or heavy hadron mass for inclusive decays is clarified within the
framework of the new formulation of HQEFT. The order corrections are
absent and contributions from terms are calculated in detail. This
enables us to reliably extract the important CKM matrix element from
the inclusive semileptonic decay rates. The resulting lifetime ratios
and are found to well agree
with the experimental data. We also calculate in detail the inclusive
semileptonic branching ratios and the ratios of the and decay
rates as well as the charm countings in the , and
systems. For decays, all the observables are found to be consistent with
the experimental data. More precise data for the decays and further
experimental measurements for the and systems will be very
useful for testing the framework of new formulation of HQEFT at the level of
higher order corrections.Comment: 20 pages, RevTex, 8 figures, 3 tables, revised version with `dressed
heavy quark' being addressed, to be published in Int. J. Mod. Phys.
Electronic structure of YbB: Is it a Topological Insulator or not?
To resolve the controversial issue of the topological nature of the
electronic structure of YbB, we have made a combined study using density
functional theory (DFT) and angle resolved photoemission spectroscopy (ARPES).
Accurate determination of the low energy band topology in DFT requires the use
of modified Becke-Johnson exchange potential incorporating the spin-orbit
coupling and the on-site Coulomb interaction of Yb electrons as large
as 7 eV. We have double-checked the DFT result with the more precise GW band
calculation. ARPES is done with the non-polar (110) surface termination to
avoid band bending and quantum well confinement that have confused ARPES
spectra taken on the polar (001) surface termination. Thereby we show
definitively that YbB has a topologically trivial B 2-Yb 5
semiconductor band gap, and hence is a non-Kondo non-topological insulator
(TI). In agreement with theory, ARPES shows pure divalency for Yb and a -
band gap of 0.3 eV, which clearly rules out both of the previous scenarios of
- band inversion Kondo TI and - band inversion non-Kondo TI. We
have also examined the pressure-dependent electronic structure of YbB,
and found that the high pressure phase is not a Kondo TI but a
\emph{p}-\emph{d} overlap semimetal.Comment: The main text is 6 pages with 4 figures, and the supplementary
information contains 6 figures. 11 pages, 10 figures in total To be appeared
in Phys. Rev. Lett. (Online publication is around March 16 if no delays.
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