78,391 research outputs found

    Large amplitude gravitational waves

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    We derive an asymptotic solution of the Einstein field equations which describes the propagation of a thin, large amplitude gravitational wave into a curved space-time. The resulting equations have the same form as the colliding plane wave equations without one of the usual constraint equations

    Ranking of 11 coastal halophytes from salt marshes in northwest Turkey according their salt tolerance

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    Salt-affected soils with high electrolyte contents limit the development of the majority of plants and serve as a habitat only for such species (halophytes) that can survive the conditions. To date, there is still much that is unknown about the physiological mechanisms, including ion relationships, that make plants salt-resistant. The primary aim of this study was to evaluate a method of ranking plants for their salt tolerance. A total of 11 coastal halophytes of the Kavak Delta were evaluated for their ability to cope with different soil salinities. For this, electrical conductivities of soils (of up to 135 dS m(-1)) were recorded and a total of 100 plant samples, including plant roots, were taken from a depth of 0-15 cm in the soil. The halophytes were ranked in the following order from highest to moderate salt tolerance: Halocnemum strobilaceum >= Salicornia fragilis >= Arthrocnemum fruticosum = Suaeda prostrata >= Salsola kali = Petrosimonia brachiata >= Juncus maritimus = Aeluropus littoralis >= Halimione portulacoides = Limonium graecum >= Artemisia santonicum. The Na+/K+ ratios of leaves perfectly reflected the salinity tolerance ranking of all halophytic species examined. It proved possible to rank the salt tolerance of halophytes by assessment of the electrical conductivity of the soil in which they grew naturally; tolerance was well predicted by the Na+/K+ ratio in the shoots

    Perturbative Matching of Heavy-Light Currents with NRQCD Heavy Quarks

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    We present further results for one-loop matching of heavy-light axial and vector currents between continuum QCD and a lattice theory with NRQCD heavy quarks and massless clover quarks.Comment: LATTICE98(heavyqk

    The monetary model of the US Dollar–Japanese Yen exchange rate: An empirical investigation

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    This article considers the long-run performance of the monetary approach to explain the dollar–yen exchange rates during a period of high international capital mobility. We apply the Johansen methodology to quarterly data over the period 1980:01–2009:04 and show that the historical inadequacy of the monetary approach is due to the breakdown of its underlying building-blocks, money demand stability and purchasing power parity. Our findings on long-run weak exogeneity tests emphasize the importance of the extended model employed here. This shows that cumulative shocks to nominal exchange rates can be explained by variables outside the usual price and interest rates

    Measuring Bremsstrahlung Photons in 200 GeV p+p Collisions

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    Direct photon production is an important observable in heavy ion collisions as photons are penetrating and therefore largely insensetive to final state effects that lead to jet quenching. Measurements of the fragmentation component to prompt photon yields in p+p and Au+Au collisions will provide both an important test of pQCD predictions and of predictions for modifications of this component in heavy ion collisions. By selecting photons associated with jets on the near side using hadron-photon correlations, fragmentation photons can be measured directly.Comment: 5 pages, 4 figures, poster presented at the 19th International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions (QM2006

    Directive emission of red conjugated polymer embedded within zero index metamaterials

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    Abstract: We numerically demonstrate an impedance-matched multilayer stacked fishnet metamaterial that has zero index with flat high transmittance from 600nm to 620nm. The effective refractive index

    Chitin-Induced Airway Epithelial Cell Innate Immune Responses Are Inhibited by Carvacrol/Thymol.

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    Chitin is produced in large amounts by fungi, insects, and other organisms and has been implicated in the pathogenesis of asthma. Airway epithelial cells are in direct contact with environmental particles and serve as the first line of defense against inhaled allergens and pathogens. The potential contributions of airway epithelial cells to chitin-induced asthma remain poorly understood. We hypothesized that chitin directly stimulates airway epithelial cells to release cytokines that promote type 2 immune responses and to induce expression of molecules which are important in innate immune responses. We found that chitin exposure rapidly induced the expression of three key type 2-promoting cytokines, IL-25, IL-33 and TSLP, in BEAS-2B transformed human bronchial epithelial cells and in A549 and H292 lung carcinoma cells. Chitin also induced the expression of the key pattern recognition receptors TLR2 and TLR4. Chitin induced the expression of miR-155, miR-146a and miR-21, each of which is known to up-regulate the expression of pro-inflammatory cytokines. Also the expression of SOCS1 and SHIP1 which are known targets of miR-155 was repressed by chitin treatment. The monoterpene phenol carvacrol (Car) and its isomer thymol (Thy) are found in herbal essential oils and have been shown to inhibit allergic inflammation in asthma models. We found that Car/Thy inhibited the effects of chitin on type 2-promoting cytokine release and on the expression of TLRs, SOCS1, SHIP1, and miRNAs. Car/Thy could also efficiently reduce the protein levels of TLR4, inhibit the increase in TLR2 protein levels in chitin plus Car/Thy-treated cells and increase the protein levels of SHIP1 and SOCS1, which are negative regulators of TLR-mediated inflammatory responses. We conclude that direct effects of chitin on airway epithelial cells are likely to contribute to allergic airway diseases like asthma, and that Car/Thy directly inhibits epithelial cell pro-inflammatory responses to chitin
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