20,635 research outputs found
Comparisons of Shark Catch Rates on Longlines Using Rope/Steel (Yankee) and Monofilament Gangions
During the months of June through September in 1991 and 1992, 71 shark longlines were fished in the Chesapeake Bight region ofthe U.S. mid-Atlantic coast with a combination of rope/steel (Yankee) and monofilament gangions. A total of 288 sharks were taken on 3,666 monofilament gangions, and 352 sharks were caught on 6,975 Yankee gangions. Catch rates between gear types differed by depth strata, by month, and by species. Analyses were divided between efforts in the nursery ground ofthe sandbar shark, Carcharhinus plumbeus, in Chesapeake Bay and efforts outside the Bay. Mean catch per unit effort (CPUE) ± SE, as sharks caught per 100 hooks fished, was significantly (P<0.05) lower for Yankee gangions. Mean CPUE's for sandbar sharks in the nursery ground were 20.6 ± 3.8 for Yankee gangions and 26.0 ± 3.0 for monofilament gangions, and mean CPUE's for all species combined outside the Bay were 3.7 ± 0.7 for Yankee gangions, and 6.9 ± 1.2 for monofilament gangions
On the equivalence of contact invariants in sutured Floer homology theories
We recently defined an invariant of contact manifolds with convex boundary in
Kronheimer and Mrowka's sutured monopole Floer homology theory. Here, we prove
that there is an isomorphism between sutured monopole Floer homology and
sutured Heegaard Floer homology which identifies our invariant with the contact
class defined by Honda, Kazez and Mati\'c in the latter theory. One consequence
is that the Legendrian invariants in knot Floer homology behave functorially
with respect to Lagrangian concordance. In particular, these invariants provide
computable and effective obstructions to the existence of such concordances.
Our work also provides the first proof which does not rely on the relative
Giroux correspondence that the vanishing or non-vanishing of Honda, Kazez and
Mati\'c's contact class is a well-defined invariant of contact manifolds.Comment: 63 pages, 13 figures; v2: corrected Lemma 3.3 and subsequent
material, many other small changes; v3: accepted version, substantially
revised to correct the proof of the main theore
Solar Nebula Magnetohydrodynamics
The dynamical state of the solar nebula depends critically upon whether or
not the gas is magnetically coupled. The presence of a subthermal field will
cause laminar flow to break down into turbulence. Magnetic coupling, in turn,
depends upon the ionization fraction of the gas. The inner most region of the
nebula ( AU) is magnetically well-coupled, as is the outermost
region ( AU). The magnetic status of intermediate scales (
AU) is less certain. It is plausible that there is a zone adjacent to the inner
disk in which turbulent heating self-consistently maintains the requisite
ionization levels. But the region adjacent to the active outer disk is likely
to be magnetically ``dead.'' Hall currents play a significant role in nebular
magnetohydrodynamics.
Though still occasionally argued in the literature, there is simply no
evidence to support the once standard claim that differential rotation in a
Keplerian disk is prone to break down into shear turbulence by nonlinear
instabilities. There is abundant evidence---numerical, experimental, and
analytic---in support of the stabilizing role of Coriolis forces.
Hydrodynamical turbulence is almost certainly not a source of enhanced
turbulence in the solar nebula, or in any other astrophysical accretion disk.Comment: 19 pages, LaTEX, ISSI Space Sciences Series No.
Fuzzy Supernova Templates II: Parameter Estimation
Wide field surveys will soon be discovering Type Ia supernovae (SNe) at rates
of several thousand per year. Spectroscopic follow-up can only scratch the
surface for such enormous samples, so these extensive data sets will only be
useful to the extent that they can be characterized by the survey photometry
alone. In a companion paper (Rodney and Tonry, 2009) we introduced the SOFT
method for analyzing SNe using direct comparison to template light curves, and
demonstrated its application for photometric SN classification. In this work we
extend the SOFT method to derive estimates of redshift and luminosity distance
for Type Ia SNe, using light curves from the SDSS and SNLS surveys as a
validation set. Redshifts determined by SOFT using light curves alone are
consistent with spectroscopic redshifts, showing a root-mean-square scatter in
the residuals of RMS_z=0.051. SOFT can also derive simultaneous redshift and
distance estimates, yielding results that are consistent with the currently
favored Lambda-CDM cosmological model. When SOFT is given spectroscopic
information for SN classification and redshift priors, the RMS scatter in
Hubble diagram residuals is 0.18 mags for the SDSS data and 0.28 mags for the
SNLS objects. Without access to any spectroscopic information, and even without
any redshift priors from host galaxy photometry, SOFT can still measure
reliable redshifts and distances, with an increase in the Hubble residuals to
0.37 mags for the combined SDSS and SNLS data set. Using Monte Carlo
simulations we predict that SOFT will be able to improve constraints on
time-variable dark energy models by a factor of 2-3 with each new generation of
large-scale SN surveys.Comment: 20 pages, 7 figures, accepted to ApJ; paper 1 is arXiv:0910.370
Program and abstracts for the 11th annual Tropical and Subtropical Fisheries Technological Conference of the Americas, January 13 - 16, 1986, Holiday Inn, International Airport, Tampa, Florida
The Tropical and Subtropical Fisheries Technological Society of the Americas is a professional , educational association of fishery techno1ogists interested in the application of science to the unique problems of production, processing, packaging, distribution and utilization of tropical and subtropical
fishery species.
Individual abstracts edited by the authors of the abstracts. Some abstracts have been excluded by author request. (26pp.
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