9,074 research outputs found

    Attraction of migratory inanga (galaxias maculatus) and koaro (galaxias brevipinnis) juveniles to adult galaxiid odours

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    The response of migratory galaxiid juveniles, inanga (Galaxias maculatus) and koaro (G. brevipinnis), to the odours of adult galaxiids was tested in a two-choice chamber apparatus. Both conspecific and heterospecific odours were tested. Inanga juveniles were attracted to adult inanga (G. maculatus), banded kokopu (G. fasciatus), and koaro (G. brevipinnis) odours. However, they were not attracted to odours from common bullies (Gobiomorphus cotidianus). Koaro juveniles exhibited a species-specific attraction to adult koaro odours only. These results demonstrate inanga uveniles can discriminate and are attracted to adult galaxiids during their migratory phase, whilst migratory koaro juveniles exhibit a species-specific attraction to adult odours similar to the pheromonal attraction previously described for juvenile banded kokopu. This strengthens the hypothesis for the use of pheromonal cues in stream and habitat selection by amphidromous galaxiids

    The calculation of three dimensional turbulent boundary layers on helicopter rotors

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    Analytical investigation of three dimensional turbulent boundary layers on helicopter rotors including cross flow derivatives and effects of centrifugal and Coriolis force

    Nitrogenase activity associated with codium species from New Zealand marine habitats

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    Nitrogenase activity, measured as acetylene reduction, was recorded at rates up to 1028 nmol.h \g * dry weight for Codium adhaerens (Cabr.) Ag. var. convolutum Dellow and Codium fragile (Sur.) Hariot subsp. tomentosoides (Van Goor) Silva collected from New Zealand habitats. In both species the ability to reduce acetylene is invariably associated with the presence of a heterocystous blue-green alga, Calothrix sp., epiphytic or embedded in the Codium thallus. A highly significant (P < 0.001) correlation between heterocyst frequency and nitrogenase activity was found. Nitrogenase and net photosynthesis of the Codium-Calothrix system have different steady-state responses to light intensity, and the kinetics of the two processes also differ in that nitrogenase is slow to respond to illumination or darkening. Glucose additions to Codium did not significantly increase nitrogenase activity. Nitrogenase is relatively insensitive to oxygen tension over the range 0-1.0 atm (0-1.033 kgf.cnT2) and still occurs at 1.5 atm (1.55 kgf.cm"2); this condition is unique in all nitrogenase systems thus far reported. Collectively these facts suggest that Calothrix is the agent primarily responsible for nitrogenase activity in these Codium species

    Experimental Outlook for the Pentaquark

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    A critical look is taken at both positive and null evidence for the Θ+\Theta^+ pentaquark. Potential problems with experiments will be discussed and the question of what conclusion can be drawn from both the positive and the null results is examined. First the question of existence of the Θ+\Theta^+ pentaquark is considered, followed by a discussion of new experiments that are either planned or in progress to answer questions about its mass, width and isospin. Finally, indirect evidence for the parity of the Θ+\Theta^+ is examined, and suggestions for experiments to measure its parity directly are given.Comment: MESON2004 conference proceedings, 10 pages, 1 figur

    Spraying for grape rot

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    Caption title.Mode of access: Internet

    Retrodirective transponder feasibility experiment

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    Test program on feasibility of digital phase measuring subsystem of pulse-coherent retrodirective transponde

    Grape rots in Ohio; Experiments in the prevention of grape rot

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    Phylogeography of Acartia tonsa Dana, 1849 (Calanoida: Copepoda) and phylogenetic reconstruction of the genus Acartia Dana, 1846

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    The calanoid copepod, Acartia tonsa Dana, 1849 is one of the most abundant and well-studied estuarian species with a worldwide distribution. In this research, we use the mitochondrial cytochrome oxidase subunit I gene to study the phylogeography of A. tonsa by analyzing sequences from specimens collected in the western Gulf of Mexico (GOM) along with all sequences from previous research. We reconstruct the phylogeny for the genus Acartia Dana, 1846 and highlight numerous potential misidentifications of Acartia species deposited in GenBank. The incorrect taxonomy assigned to some of these sequences results in apparently paraphyletic relationships. This study demonstrates that A. tonsa is a species complex with multiple, deeply diverging, lineages of varying geographic affinities. Multiple new lineages are found in the Texas GOM that is basal to northwestern Atlantic lineages with phylogenetic connectivity also observed between Brazil and the Texas GOM. Results show two major phylogeographic breaks in the North American continent, one at the border between the Gulf of Mexico and the Northwest Atlantic, and the other at about 35° N. One of the major clades in the A. tonsa species complex shows a clear pattern of divergence that follows the prevailing currents. Within this clade, older lineages are found in the western GOM while newer lineages are found in the eastern GOM and the southern coast of the northwest Atlantic, with the youngest lineages diversifying in the north. The results show that A. tonsa can be used as a model species for observing phylogeographical structuring of coastal plankton along the American continent

    The complete mitochondrial genome of Tanacetipathes thamnea Warner, 1981 (Antipatharia: Myriopathidae)

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    Specimens of the black coral Tanacetipathes thamnea were collected from the Northwestern Gulf of Mexico. The complete mitochondrial genome of one of these specimens was obtained from genomic DNA by next-generation sequencing technology on the Illumina HiSeq 2500. Only three species of black corals have a completely sequenced mitochondrial genome. These were used to reconstruct the phylogeny for the order Antipatharia. The mitochondrial genome of T. thamnea is 17,712 base pairs and contains 13 protein-coding genes, 2 ribosomal RNAs, and 2 transfer RNAs in the following order: 16s RNA, COX3, COX1 (with intron), ND4L, COX2, ND4, ND6, ATP8, ATP6, and ND5 (with intron and copies of ND1 and ND3), tRNA-Trp, ND2, 12s RNA, CYTB, tRNA-Met. The gene arrangement is the same as that for Myriopathes japonica with a nearly identical sequence (99.35% identical). These results show that the mitochondrial genome within the family Myriopathidae is highly conserved

    A wide band gap metal-semiconductor-metal nanostructure made entirely from graphene

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    A blueprint for producing scalable digital graphene electronics has remained elusive. Current methods to produce semiconducting-metallic graphene networks all suffer from either stringent lithographic demands that prevent reproducibility, process-induced disorder in the graphene, or scalability issues. Using angle resolved photoemission, we have discovered a unique one dimensional metallic-semiconducting-metallic junction made entirely from graphene, and produced without chemical functionalization or finite size patterning. The junction is produced by taking advantage of the inherent, atomically ordered, substrate-graphene interaction when it is grown on SiC, in this case when graphene is forced to grow over patterned SiC steps. This scalable bottomup approach allows us to produce a semiconducting graphene strip whose width is precisely defined within a few graphene lattice constants, a level of precision entirely outside modern lithographic limits. The architecture demonstrated in this work is so robust that variations in the average electronic band structure of thousands of these patterned ribbons have little variation over length scales tens of microns long. The semiconducting graphene has a topologically defined few nanometer wide region with an energy gap greater than 0.5 eV in an otherwise continuous metallic graphene sheet. This work demonstrates how the graphene-substrate interaction can be used as a powerful tool to scalably modify graphene's electronic structure and opens a new direction in graphene electronics research.Comment: 11 pages, 7 figure
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