13,806 research outputs found
A Brief Interpretation of Summer Flounder, Paralichthys dentatus, Movements and Stock Structure with New Tagging Data on Juveniles
Summer flounder, Paralichthys dentatus, are managed as a single stock along the Atlantic coast from the U.S.– Canada border to the southern border of North Carolina. Justification of the single-stock approach is based on lack of genetic evidence for multiple stocks and the difficulty presented by managing the species from Cape Hatteras to the U.S.–Canada border. In this review, we present an interpretation of various morphometric, meristic, biochemical, and tagging studies, published and unpublished, that indicate the presence of two, or possibly three, distinct stocks in the management area. In addition, we have included new data from a tagging study that was conducted on juveniles from Virginia that aids in defining the stock(s) north of Cape Hatteras. Summer flounder, overfished for the past two decades, is recovering, and reconsideration of proposed stock structure could have direct implications for management policy decisions
Numerical Analysis of the Capacities for Two-Qubit Unitary Operations
We present numerical results on the capacities of two-qubit unitary
operations for creating entanglement and increasing the Holevo information of
an ensemble. In all cases tested, the maximum values calculated for the
capacities based on the Holevo information are close to the capacities based on
the entanglement. This indicates that the capacities based on the Holevo
information, which are very difficult to calculate, may be estimated from the
capacities based upon the entanglement, which are relatively straightforward to
calculate.Comment: 9 pages, 10 figure
D7-Brane Chaotic Inflation
We analyze string-theoretic large-field inflation in the regime of
spontaneously-broken supergravity with conventional moduli stabilization by
fluxes and non-perturbative effects. The main ingredient is a shift-symmetric
Kahler potential, supplemented by flux-induced shift symmetry breaking in the
superpotential. The central technical observation is that all these features
are present for D7-brane position moduli in Type IIB orientifolds, allowing for
a realization of the axion monodromy proposal in a controlled string theory
compactification. On the one hand, in the large complex structure regime the
D7-brane position moduli inherit a shift symmetry from their mirror-dual Type
IIA Wilson lines. On the other hand, the Type IIB flux superpotential
generically breaks this shift symmetry and allows, by appealing to the large
flux discretuum, to tune the relevant coefficients to be small. The
shift-symmetric direction in D7-brane moduli space can then play the role of
the inflaton: While the D7-brane circles a certain trajectory on the Calabi-Yau
many times, the corresponding F-term energy density grows only very slowly,
thanks to the above-mentioned tuning of the flux. Thus, the large-field
inflationary trajectory can be realized in a regime where Kahler, complex
structure and other brane moduli are stabilized in a conventional manner, as we
demonstrate using the example of the Large Volume Scenario.Comment: 8 pages, 2 figures; v2: references adde
Self-consistent stationary MHD shear flows in the solar atmosphere as electric field generators
Magnetic fields and flows in coronal structures, for example, in gradual
phases in flares, can be described by 2D and 3D magnetohydrostatic (MHS) and
steady magnetohydrodynamic (MHD) equilibria. Within a physically simplified,
but exact mathematical model, we study the electric currents and corresponding
electric fields generated by shear flows. Starting from exact and analytically
calculated magnetic potential fields, we solveid the nonlinear MHD equations
self-consistently. By applying a magnetic shear flow and assuming a nonideal
MHD environment, we calculated an electric field via Faraday's law. The formal
solution for the electromagnetic field allowed us to compute an expression of
an effective resistivity similar to the collisionless Speiser resistivity. We
find that the electric field can be highly spatially structured, or in other
words, filamented. The electric field component parallel to the magnetic field
is the dominant component and is high where the resistivity has a maximum. The
electric field is a potential field, therefore, the highest energy gain of the
particles can be directly derived from the corresponding voltage. In our
example of a coronal post-flare scenario we obtain electron energies of tens of
keV, which are on the same order of magnitude as found observationally. This
energy serves as a source for heating and acceleration of particles.Comment: 11 pages, 9 figures, accepted to Astronomy and Astrophysic
Non-Bilocal Measurement via Entangled State
Two observers, who share a pair of particles in an entangled mixed state, can
use it to perform some non-bilocal measurement over another bipartite system.
In particular, one can construct a specific game played by the observers
against a coordinator, in which they can score better than a pair of observers
who only share a classical communication channel.Comment: 6 pages. minor change
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