1,725 research outputs found
A Brief History of Bycatch Management Measures for Eastern Bering Sea Groundfish Fisheries
Bycatch management measures instituted for groundfish fisheries of the eastern Bering Sea have focused on reducing the incidental capture and injury of species traditionally harvested by other fisheries. These species include king crab, Paralithodes and Lithodes spp.; Tanner crab, Chionoecetes spp.; Pacific herring, Clupea harengus pallasi; Pacific halibut, Hippoglossus stenolepis; and Pacific salmon and steelhead trout, Oncorhynchus spp. Collectively, these species are called "prohibited species," as they cannot be retained as bycatch in groundfish fisheries and must be discarded with a minimum of injury
Beauty Quark Fragmentation Into Strange B Mesons
Using the recent measurement of the total production rate for and
mesons in electron-positron annihilation to determine the strange quark
mass parameter in the fragmentation functions we
calculate the momentum distributions of the and mesons.Comment: 8 pages, 2 figures (not included but available upon request),
standard LaTeX file, Report # NUHEP-TH-94-1
Ecosystem-based Management for Protected Species in the North Pacific Fisheries
In the North Pacific Ocean, an ecosystem-based fishery management approach has been adopted. A significant objective of this approach is to reduce interactions between fishery-related activities and protected species. We review management measures developed by the North Pacific Fishery Management Council and the National Marine Fisheries Service to reduce effects of the groundfish fisheries off Alaska on marine mammals and seabirds, while continuing to provide economic opportunities for fishery participants. Direct measures have been taken to mitigate known fishery impacts, and precautionary measures have been taken for species with potential (but no documented) interactions with the groundfish fisheries. Area closures limit disturbance to marine mammals at rookeries and haulouts, protect sensitive benthic habitat, and reduce potential competition for prey resources. Temporal and spatial dispersion of catches reduce the localized impact of fishery removals. Seabird avoidance measures have been implemented through collaboration with fishery participants and have been highly successful in reducing seabird bycatch. Finally, a comprehensive observer monitoring program provides data on the location and extent of bycatch of marine mammals and seabirds. These measures provide managers with the flexibility to adapt to changes in the status of protected species and evolving conditions in the fisheries. This review should be useful to fishery managers as an example of an ecosystem-based approach to protected species management that is adaptive and accounts for multiple objectives
Calculating the Shear and Divergence of Light Rays
The purpose of this research was to calculate the shear and divergence of light rays bundles as they pass black holes. We defined a Lagrangian using the Schwarzchild metric then used the Euler-Lagrangian equation to create 6 first order OED’s for the light rays path. Next we found tangent vectors to the light ray so we could calculate Ψ0. In order to calculate the shear and divergence the method of calculation required simultaneously solving 16 ordinary differential equations. We used Mathematica to calculate how these light rays act but first we had to use calculus and algebra to derive these equations. We started from the Schwarzchild metric to find the Langrangian for the motion of the light rays. We then got results which were 6 ODE’s that gave velocity and acceleration in (Τ, r, θ, ϕ). Then we found the tangent vectors to these paths which allows us to solve for Ψ0 and finally we solved for the divergence and shear of the light rays
On the Determination of and from Hadronic Two Body Decays
{}From Class I decays : B^o \ra \pi^+ ( \rho^+ ) + D^- ( {D^*}^- ), we
determine , and from Class III decays : B^+ \ra \pi^+ ( \rho^+ ) +
\ol{D}^o ( {\ol{D}^*}^o ), we determine an allowed domain in the plane. We find that within one standard deviation errors, the allowed band
of from Class I decays is at least three standard deviations removed from
the allowed domain from Class III decays.If we expand the
experimental errors to two standard deviations we do find a small intersection
between the band and the allowed domain. The results
usually quoted in the literature lie in this intersection. We suggest : (1) an
independent measurement of the branching ratio for the Class III decay, B^+
\ra \rho^+ \ol{D}^o , (2) a high-statistics measurement of the branching ratio
of the Class I decay, B \ra \ol{D} ( \ol{D}^* ) + D_s ( D_s^* ) in both
charged states, and (3) a measurement of the longitudinal polarization fraction
in the Class III decay B^+ \ra \rho^+ {\ol{D}^*}^o to shed more light on the
questions involved .Comment: 9pages(Latex)+4 figures(PS file appended), PAR/LPTHE/94-2
Implications of factorization for the determination of hadronic form factors in D_s^+ \ra \phi transition
Using factorization we determine the allowed domains of the ratios of form
factors, and , from the experimentally
measured ratio R_h \equiv \Gamma(D_s^+ \ra \phi \rho^+)/\Gamma(D_s^+ \ra \phi
\pi^+) assuming three different scenarios for the -dependence of the form
factors. We find that the allowed domains overlap with those obtained by using
the experimentally measured ratio R_{s\ell} = \Gamma(D^+_s \ra \phi \ell^+
\nu_{\ell})/\Gamma(D^+_s \ra \phi \pi^+) provided that the phenomenological
parameter is . Such a comparison presents a genuine test of
factorization. We calculate the longitudinal polarization fraction,
\Gamma_L/\Gamma \equiv \Gamma(D_s^+ \ra \phi_L \rho^+_L)/\Gamma(D_s^+ \ra \phi
\rho^+), in the three scenarios for the -dependence of the form factors
and emphasize the importance of measuring . Finally we
discuss the -distribution of the semileptonic decay and find that it is
rather insensitive to the scenarios for the -dependence of the form
factors, and unless very accurate data can be obtained it is unlikely to
discriminate between the different scenarios. Useful information on the value
of might be obtained by the magnitude of the -distribution near . However the most precise information on and would come from the
knowledge of the longitudinal and left-right transverse polarizations of the
final vector mesons in hadronic and/or semileptonic decays.Comment: Latex 10 pages( 4 figures), PAR/LPTHE/94-3
AIERO: An algorithm for identifying engineering relationships in ontologies
Semantic technologies are playing an increasingly popular role as a means for advancing the capabilities of knowledge management systems. Among these advancements, researchers have successfully leveraged semantic technologies, and their accompanying techniques, to improve the representation and search capabilities of knowledge management systems. This paper introduces a further application of semantic techniques. We explore semantic relatedness as a means of facilitating the development of more “intelligent” engineering knowledge management systems. Using semantic relatedness quantifications to analyze and rank concept pairs, this novel approach exploits semantic relationships to help identify key engineering relationships, similar to those leveraged in change management systems, in product development processes. As part of this work, we review several different semantic relatedness techniques, including a meronomic technique recently introduced by the authors. We introduce an aggregate measure, termed “An Algorithm for Identifying Engineering Relationships in Ontologies,” or AIERO, as a means to purposely quantify semantic relationships within product development frameworks. To assess its consistency and accuracy, AIERO is tested using three separate, independently developed ontologies. The results indicate AIERO is capable of returning consistent rankings of concept pairs across varying knowledge frameworks. A PCB (printed circuit board) case study then highlights AIERO’s unique ability to leverage semantic relationships to systematically narrow where engineering interdependencies are likely to be found between various elements of product development processes
Form Factor Relations for Heavy-to-Light Transitions
Assuming simple properties of the spectator particle in weak decays the form
factors of hadronic current matrix elements are shown to be related to a single
universal function. The Isgur-Wise result for heavy-to-heavy transitions
follows as well as similar relations for heavy-to-light decay processes. The
approximation should hold for total energies of the final particle large
compared to the confinement scale. A comparison with experimentally determined
D-decay form factors and QCD sum rule results for B-decays is very encouraging.Comment: 12 pages, Latex; Relativistic covariant form, results unchanged,
references added, to be published in Physics Lett.
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