5,155 research outputs found

    The Living Murray NSW Market Purchase Measure: A survey of participants in permanent water trading for the environment

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    The Living Murray Initiative was established to recover 500 Gigalitres in average annual flows to address the declining environmental health of the Murray-Darling river system. The NSW Market Purchase Measure was initiated by the New South Wales Government as part of The Living Murray Initiative with the aim of purchasing up to 125 Gigalitres of high and medium reliability entitlements within the NSW southern connected part of the Murray-Darling Basin. The commencement of this measure provided an opportunity to survey participants in permanent water trading for an environmental outcome to determine general land use and socio-economic information as well as specific information regarding their current water use, future intentions and their opinion of the implementation of the water purchase process. The results of the survey will also assist in understanding the nature of the participants in this process relative to the broader irrigator/regional population. Importantly, the survey outcomes will help to improve understanding of participant circumstances and provide important lessons for future water purchase programs.Resource /Energy Economics and Policy,

    Resonant tunneling of electromagnetic waves through polariton gaps

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    We consider resonant tunneling of electromagnetic waves through an optical barrier formed by dielectric layers with the frequency dispersion of their dielectric permiability. The frequency region between lower and upper polariton branches in these materials presents a stop band for electromagnetic waves. We show that resonance tunneling through this kind of barriers is qualitatevely different from tunneling through other kind of optical barriers as well as from quantum mechanic tunneling through a rectangular barrier. We find that the width of the resonance maxima of the transmission coeffcient tends to zero as frequency approach the lower boundary of the stop band in a very sharp non-analytical way. Resonance transmission peaks give rise to new photonic bands inside the stop band if one considers periodical array of the layers.Comment: 8 pages, 5 figure

    Heterozygous mis-sense mutations in Prkcb as a critical determinant of anti-polysaccharide antibody formation

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    To identify rate-limiting steps in T cell-independent type 2 (TI-2) antibody production against polysaccharide antigens, we performed a genome-wide screen by immunizing several hundred pedigrees of C57BL/6 mice segregating ENU-induced mis-sense mutations. Two independent mutations, Tilcara and Untied, were isolated that semi-dominantly diminished antibody against polysaccharide but not protein antigens. Both mutations resulted from single amino acid substitutions within the kinase domain of Protein Kinase C Beta (PKCβ). In Tilcara, a Ser552>Pro mutation occurred in helix G, in close proximity to a docking site for the inhibitory N-terminal pseudosubstrate domain of the enzyme, resulting in almost complete loss of active, autophosphorylated PKCβI whereas the amount of alternatively spliced PKCβII protein was not markedly reduced. Circulating B cell subsets were normal and acute responses to BCR-stimulation such as CD25 induction and initiation of DNA synthesis were only measurably diminished in Tilcara homozygotes, whereas the fraction of cells that had divided multiple times was decreased to an intermediate degree in heterozygotes. These results, coupled with evidence of numerous mis-sense PRKCB mutations in the human genome, identify Prkcb as a genetically sensitive step likely to contribute substantially to population variability in anti-polysaccharide antibody levels

    Comparative aspects of trophoblast development and placentation

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    Based on the number of tissues separating maternal from fetal blood, placentas are classified as epitheliochorial, endotheliochorial or hemochorial. We review the occurrence of these placental types in the various orders of eutherian mammals within the framework of the four superorders identified by the techniques of molecular phylogenetics. The superorder Afrotheria diversified in ancient Africa and its living representatives include elephants, sea cows, hyraxes, aardvark, elephant shrews and tenrecs. Xenarthra, comprising armadillos, anteaters and sloths, diversified in South America. All placentas examined from members of these two oldest superorders are either endotheliochorial or hemochorial. The superorder Euarchontoglires includes two sister groups, Glires and Euarchonta. The former comprises rodents and lagomorphs, which typically have hemochorial placentas. The most primitive members of Euarchonta, the tree shrews, have endotheliochorial placentation. Flying lemurs and all higher primates have hemochorial placentas. However, the lemurs and lorises are exceptional among primates in having epitheliochorial placentation. Laurasiatheria, the last superorder to arise, includes several orders with epitheliochorial placentation. These comprise whales, camels, pigs, ruminants, horses and pangolins. In contrast, nearly all carnivores have endotheliochorial placentation, whilst bats have endotheliochorial or hemochorial placentas. Also included in Laurasiatheria are a number of insectivores that have many conserved morphological characters; none of these has epitheliochorial placentation. Consideration of placental type in relation to the findings of molecular phylogenetics suggests that the likely path of evolution in Afrotheria was from endotheliochorial to hemochorial placentation. This is also a likely scenario for Xenarthra and the bats. We argue that a definitive epitheliochorial placenta is a secondary specialization and that it evolved twice, once in the Laurasiatheria and once in the lemurs and lorises

    The Affect of Host Plant on Aphid Population Growth

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    Citation: Dostal, E. (2017). The Affect of Host Plant on Aphid Population Growth . 1st Annual Undergraduate Research Experience in Entomology Symposium, November 16, 2016. Manhattam, KS.Damage from aphids to wheat plants is noticeable from a distance and can result in water stress, reduced plant growth and wilting. Different aphids are said to cause different colorations when damaging the plants. The comparison of aphid performance on a set of closely related species can help identify traits related to plant defense and aphid performance. Such studies can help inform future experiments that study specific mechanisms of plant resistance. Its important to know what causes aphids to damage some plants more than others so we can find ways to prevent it. I observed the effects that wheat, barley and sorghum have on the population growth rate of corn leaf aphids and green bugs. Also, the effect the aphids have on the plants and how much they damage each type. Will one aphid species have an exceptionally higher rate of reproduction on a specific plant? Is aphid population growth affected by competition between species? I found the green bug population grew faster than the corn leaf aphids and they preferred the wheat, which in return resulted in the wheat having the highest plant damage

    Multibarrier tunneling

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    We study the tunneling through an arbitrary number of finite rectangular opaque barriers and generalize earlier results by showing that the total tunneling phase time depends neither on the barrier thickness nor on the inter-barrier separation. We also predict two novel peculiar features of the system considered, namely the independence of the transit time (for non resonant tunneling) and the resonant frequency on the number of barriers crossed, which can be directly tested in photonic experiments. A thorough analysis of the role played by inter-barrier multiple reflections and a physical interpretation of the results obtained is reported, showing that multibarrier tunneling is a highly non-local phenomenon.Comment: RevTex, 7 pages, 1 eps figur
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