9,827 research outputs found
Quantifying finfish and blue crab use of created oyster reefs in the lower Chesapeake Bay
Structurally complex reefs created by the eastern oyster Crassostrea virginica provide a host of ecosystem services yet have experienced significant declines, prompting extensive restoration efforts. We investigate the use of created oyster reefs in the lower Bay by mobile finfish and blue crabs with field surveys and diet analysis. The results of this study provide insight into how restoration activities influence estuarine community dynamics and the provision of ecosystem services
The Effects of Massive Substructures on Image Multiplicities in Gravitati onal Lenses
Surveys for gravitational lens systems have typically found a significantly
larger fraction of lenses with four (or more) images than are predicted by
standard ellipsoidal lens models (50% versus 25-30%). We show that including
the effects of smaller satellite galaxies, with an abundance normalized by the
observations, significantly increases the expected number of systems with more
than two images and largely explains the discrepancy. The effect is dominated
by satellites with ~20% the luminosity of the primary lens, in rough agreement
with the typical luminosities of the observed satellites. We find that the lens
systems with satellites cannot, however, be dropped from estimates of the
cosmological model based on gravitational lens statistics without significantly
biasing the results.Comment: 23 pages, 7 figures, more discussion of sis vs sie and inclusion of
uncorrelated contribution
Rank 3 permutation characters and maximal subgroups
In this paper we classify all maximal subgroups M of a nearly simple
primitive rank 3 group G of type L=Omega_{2m+1}(3), m > 3; acting on an L-orbit
E of non-singular points of the natural module for L such that 1_P^G <=1_M^G
where P is a stabilizer of a point in E. This result has an application to the
study of minimal genera of algebraic curves which admit group actions.Comment: 41 pages, to appear in Forum Mathematicu
Mass Spectral Fragmentation Study of Substituted 1,3-Diphenyl- 2-pyrazolines
The electron impact induced fragmentation of twenty two 1,3-
-diphenyl-2-pyrazolines mono-, di- and trisubstituted in one or in
both phenyl rings was studied by deuterium labelling, high and
low resolution mass spectrometry, and ion kinetic energy spectroscopy.
The fragmentation patterns are discussed taking into account
especially the nature of the substituent and the position of substitution.
The results, compared with those for the unsubstituted compound,
showed that in general the phenyl ring substitution does
not affect its fragmentation. The formation of stable quinoid-type
ions directs many fragmentation pathways of methoxy substituted
compounds
End states, ladder compounds, and domain wall fermions
A magnetic field applied to a cross linked ladder compound can generate
isolated electronic states bound to the ends of the chain. After exploring the
interference phenomena responsible, I discuss a connection to the domain wall
approach to chiral fermions in lattice gauge theory. The robust nature of the
states under small variations of the bond strengths is tied to chiral symmetry
and the multiplicative renormalization of fermion masses.Comment: 10 pages, 4 figures; final version for Phys. Rev. Let
Multiplicity-free representations of algebraic groups II
We continue our work (started in ``Multiplicity-free representations of
algebraic groups", arXiv:2101.04476), on the program of classifying triples
, where are simple algebraic groups over an algebraically closed
field of characteristic zero with , and is an irreducible module for
such that the restriction is multiplicity-free. In this
paper we handle the case where is of type , and is irreducibly embedded
in of type or . It turns out that there are relatively few triples
for of arbitrary rank, but a number of interesting exceptional examples
arise for small ranks.Comment: 60 page
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