9,421 research outputs found
Sea Otter, Enhydra lutris, mortalities in California, 1968 through 1993
Sea otter, Enhydra lutris, mortality in California and the relative contribution from specific causes was assessed for the 26 years from 1968 through 1993. There were 2,082 dead sea otters recorded from Tomales Bay (Marin County) south to Bluff Cove (Los Angeles County) during that period. The average number of carcasses recorded was 80 per year and seven per month. Sex was identified in 87% (n=1,819) of the cases and was composed of 47% female and 53% male. A relative age was assigned to 97% (n=2,017) of the cases and was composed of 28% pup, 18% subadult and 54% adult.
Specific causes of death were determined for 26% (n=55 1) of the cases. The majority of these (n=381) were considered to be due to natural causes and included the following specific causes: shark bitten (n=78), probably shark bitten (n=106), other natural causes (n=140), and mating wounds (n=57). The remaining (n=170) were considered to be due to human-related causes and included the following specific causes: shot
(n=72), probably shot (n=8), net drowned (n=76), and other human causes (n=14).
The large proportion of carcasses without an identified specific cause of death prompted a more detailed necropsy effort in 1992 and 1993. During that period, 78 of the 232 recovered carcasses were examined by veterinary pathologists and a specific cause of death was determined in 76% (n=59) of the cases. This effort identified a wide range of specific causes of death that otherwise may have been categorized as "unknown without trauma". Considering the variety of diseases diagnosed in this expanded necropsy program, it would be prudent to continue this level of examination to refine our knowledge of sea otter pathology. (48pp.
The construction and evaluation of an instrument to determine the sports knowledge of boys from grades five through eight
Thesis (Ed.M.)--Boston Universit
Density functional theory embedding for correlated wavefunctions: Improved methods for open-shell systems and transition metal complexes
Density functional theory (DFT) embedding provides a formally exact framework
for interfacing correlated wave-function theory (WFT) methods with lower-level
descriptions of electronic structure. Here, we report techniques to improve the
accuracy and stability of WFT-in-DFT embedding calculations. In particular, we
develop spin-dependent embedding potentials in both restricted and unrestricted
orbital formulations to enable WFT-in-DFT embedding for open-shell systems, and
we develop an orbital-occupation-freezing technique to improve the convergence
of optimized effective potential (OEP) calculations that arise in the
evaluation of the embedding potential. The new techniques are demonstrated in
applications to the van-der-Waals-bound ethylene-propylene dimer and to the
hexaaquairon(II) transition-metal cation. Calculation of the dissociation curve
for the ethylene-propylene dimer reveals that WFT-in-DFT embedding reproduces
full CCSD(T) energies to within 0.1 kcal/mol at all distances, eliminating
errors in the dispersion interactions due to conventional exchange-correlation
(XC) functionals while simultaneously avoiding errors due to subsystem
partitioning across covalent bonds. Application of WFT-in-DFT embedding to the
calculation of the low-spin/high-spin splitting energy in the hexaaquairon(II)
cation reveals that the majority of the dependence on the DFT XC functional can
be eliminated by treating only the single transition-metal atom at the WFT
level; furthermore, these calculations demonstrate the substantial effects of
open-shell contributions to the embedding potential, and they suggest that
restricted open-shell WFT-in-DFT embedding provides better accuracy than
unrestricted open-shell WFT-in-DFT embedding due to the removal of spin
contamination.Comment: 11 pages, 5 figures, 2 table
“It’s Cultural, Beautiful, and Creative”: Assessing the Impact of a Beading Project with the Hopeful Connections Alaska Native Cancer Support Group
High efficiency InGaAs solar cells on Si by InP layer transfer
InP/Si substrates were fabricated through wafer bonding and helium-induced exfoliation of InP, and InGaAs solar cells lattice matched to bulk InP were grown on these substrates using metal-organic chemical-vapor deposition. The photovoltaic characteristics of the InGaAs cells fabricated on the wafer-bonded InP/Si substrates were comparable to those synthesized on commercially available epiready InP substrates, thus providing a demonstration of wafer-bonded InP/Si substrates as an alternative to bulk InP substrates for solar cell applications
CHEMICAL DEFENSE AND MAMMALIAN HERBIVORES
1. Plant Metabolism 2. Phytochemical Variation in Plants 3. Plant Defense Theory 4. Mammalian Metabolism of Phytochemicals 5. Mammalian Herbivory Related Chapter
Using genotype abundance to improve phylogenetic inference
Modern biological techniques enable very dense genetic sampling of unfolding
evolutionary histories, and thus frequently sample some genotypes multiple
times. This motivates strategies to incorporate genotype abundance information
in phylogenetic inference. In this paper, we synthesize a stochastic process
model with standard sequence-based phylogenetic optimality, and show that tree
estimation is substantially improved by doing so. Our method is validated with
extensive simulations and an experimental single-cell lineage tracing study of
germinal center B cell receptor affinity maturation
Building End-User Thesauri from Full-Text
We are interested in the possible contribution of end-user thesauri to the improvement of information retrieval by end- users. Thesauri (from the Greek for treasure or treasury) in information retrieval attempt to record and display relations among concepts and terms -- to be treasuries of concepts and the terms that represent them. End-user thesauri are designed to guide and facilitate end-user searching of textual databases (both full-text databases and reference databases that contain only surrogates of full-texts, such as abstracts). End-user thesauri link: the vocabulary of the searcher and the vocabulary of the database, functioning as part of the user database interface. End-user thesauri are not designed to guide indexing, although they can be used to suggest terms, much like writers have used Roget's thesaurus for centuries
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