10,337 research outputs found

    A report on the sea otter, Enhydra lutris L., in California

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    This report discusses in detail findings and observations of 5 years of research on the sea otter population and its relationship to the nearshore marine environment in California. Initial efforts were directed at providing some relief to the commercial abalone fishery in the Cambria - Point Estero area north of Morro Bay. This fishery has subsequently collapsed along with other commercial and sport abalone and sport crab fisheries throughout the sea otter's range due to continued sea otter foraging. Capturing, tagging and translocation studies, censusing studies, examination of sea otter remains, habitat surveys, food habits observations and studies on otters in captivity provide a broad base of information on the expanding sea otter population in California and its effects on resources utilized by man. Recommendations for sea otter management consistent with esthetic, recreational, and commercial uses of marine resources are included in this report. (95pp.

    Convex optimization for the planted k-disjoint-clique problem

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    We consider the k-disjoint-clique problem. The input is an undirected graph G in which the nodes represent data items, and edges indicate a similarity between the corresponding items. The problem is to find within the graph k disjoint cliques that cover the maximum number of nodes of G. This problem may be understood as a general way to pose the classical `clustering' problem. In clustering, one is given data items and a distance function, and one wishes to partition the data into disjoint clusters of data items, such that the items in each cluster are close to each other. Our formulation additionally allows `noise' nodes to be present in the input data that are not part of any of the cliques. The k-disjoint-clique problem is NP-hard, but we show that a convex relaxation can solve it in polynomial time for input instances constructed in a certain way. The input instances for which our algorithm finds the optimal solution consist of k disjoint large cliques (called `planted cliques') that are then obscured by noise edges and noise nodes inserted either at random or by an adversary

    A review of California sea otter, Enhydra lutris, surveys

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    Recent surveys (1977 to 1983) of the sea otter, Enhydra lutris, in California were summarized and compared to past surveys, to evaluate the adequacy of current survey design and to-make inferences about current population status. Ground counts within selected index areas provided the best indicator of population trends. These data suggest a rather remarkable stability in the long-term occupied range. Rangewide aerial surveys with ground truth stations provided the best available data for estimating total population size. The most recent (1979) survey yielded a population estimate of approximately 1500 sea otters. Comparisons with past surveys suggest there have been no demonstrable changes in population size since at least 1976. (34pp.

    A simulated translocation of sea otters, Enhydra lutris, with a review of capture, transport and holding techniques

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    A number of techniques and pieces of equipment judged necessary for the translocation of sea otters were field tested. Captures were accomplished with either a scuba diver operated capture device (Wilson trap), a surface set tangle net or a dip net. A portable floating pen proved very satisfactory for simultaneously holding at least ten otters for several days. Commercially available pet transport kennels, with the capability of holding water, were adequate for maintaining the otter's pelage in good condition during a transport of approximately five hours duration. Subsequent observations indicated no apparent stress related dispersal. (17pp.

    Advanced communications payload for mobile applications

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    An advanced satellite payload is proposed for single hop linking of mobile terminals of all classes as well as Very Small Aperture Terminal's (VSAT's). It relies on an intensive use of communications on-board processing and beam hopping for efficient link design to maximize capacity and a large satellite antenna aperture and high satellite transmitter power to minimize the cost of the ground terminals. Intersatellite links are used to improve the link quality and for high capacity relay. Power budgets are presented for links between the satellite and mobile, VSAT, and hub terminals. Defeating the effects of shadowing and fading requires the use of differentially coherent demodulation, concatenated forward error correction coding, and interleaving, all on a single link basis

    Limestone Deposits vs. Beneficiation

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    Author Institution: Alpha Portland Cement Company, Easton, PennsylvaniaLimestone for portland cement must be beneficiated to produce uniform raw material for the kiln. Careful quarrying and selective recovery are factors in this process, but the chief aspects of beneficiation are "in plant" processes, such as crushing and screening, washing, grinding, flotation, and heavy-media separation. Numerous technical and economic problems exist. Detailed studies of the limestone deposit and the stone itself are required for intelligent beneficiation

    Structural basis for sequence specific DNA binding and protein dimerization of HOXA13.

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    The homeobox gene (HOXA13) codes for a transcription factor protein that binds to AT-rich DNA sequences and controls expression of genes during embryonic morphogenesis. Here we present the NMR structure of HOXA13 homeodomain (A13DBD) bound to an 11-mer DNA duplex. A13DBD forms a dimer that binds to DNA with a dissociation constant of 7.5 nM. The A13DBD/DNA complex has a molar mass of 35 kDa consistent with two molecules of DNA bound at both ends of the A13DBD dimer. A13DBD contains an N-terminal arm (residues 324 - 329) that binds in the DNA minor groove, and a C-terminal helix (residues 362 - 382) that contacts the ATAA nucleotide sequence in the major groove. The N370 side-chain forms hydrogen bonds with the purine base of A5* (base paired with T5). Side-chain methyl groups of V373 form hydrophobic contacts with the pyrimidine methyl groups of T5, T6* and T7*, responsible for recognition of TAA in the DNA core. I366 makes similar methyl contacts with T3* and T4*. Mutants (I366A, N370A and V373G) all have decreased DNA binding and transcriptional activity. Exposed protein residues (R337, K343, and F344) make intermolecular contacts at the protein dimer interface. The mutation F344A weakens protein dimerization and lowers transcriptional activity by 76%. We conclude that the non-conserved residue, V373 is critical for structurally recognizing TAA in the major groove, and that HOXA13 dimerization is required to activate transcription of target genes

    A CENSORED SYSTEM ESTIMATION OF HISPANIC HOUSEHOLD FOOD CONSUMPTION PATTERNS

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    A system of nine censored Engel curve equations was estimated for Hispanic households in the U.S.: grains, vegetables, fruits, milk, meat, legumes, fats, sugar, and beverages. Income and household size elasticities, with their respective confidence intervals, are reported and the results compared with other ethnic groups in the U.S.Food Consumption/Nutrition/Food Safety,

    COMPARISONS OF HISPANIC HOUSEHOLDS' DEMAND FOR MEATS WITH OTHER ETHNIC GROUPS

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    The objective of this research was to analyze the demand patterns of Hispanic households for meats in comparison with other ethnic groups using data from the 1998 Consumer Expenditure Survey. A system of demand equations of the LinQuad form were estimated for ten meat products using an incomplete system of censored equations. Hispanic households showed a clear preference for beef. Price, income, and household-size elasticities were estimated for each meat product by ethnic group. The demand for ground beef was the most income-inelastic product regardless of ethnicity. Household size had a positive effect on the probability of consuming a particular meat product but a negative effect on actual item expenditures.Consumer/Household Economics, Demand and Price Analysis,

    Snip, Snap, Snout: THIS TALE IS TOLD OUT

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    Mythology has shaped human thought and experience since before recorded history. Passed from one generation to the next, myths elevate and aggrandize realities that are difficult, complex or horrifying. This is what makes us human, an inspiring capacity toward metaphor and the ability to make beauty, lyricism and splendor—order from the chaos. Within mythology, the cause and effect of both misery and joy may be explored in their wholeness. In this act of imaginative translation, we may come to understand how misery and joy are naturally coexisting. In my thesis exhibition this tale is told out, I use the layering of mythology, iconography and personal narrative to explore the animal nature of humans and how these relate to the ways we establish and sustain relationships. I am interested in exploring the imagery and iconography of mythologies and their historic relationship to pastoral life, animal husbandry and women’s craft—drawing on my own experience of growing up on a sheep farm. This paper will demonstrate how my thesis work is based in contemporary tales of trauma, joy and womanhood
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