1,161 research outputs found

    Concentrations of 137Cs^{137}Cs, 40K^{40}K radionuclides and some heavy metals in soil samples of Chochołowska Valley from Tatra National Park

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    This paper presents the results of determination of artificial 137Cs^{137}Cs and natural 40K^{40}K activity concentrations and some heavy metals in soil samples from the region of one of the main valleys of Tatra National Park (Chochołowska). Our investigation concentrated on 137Cs^{137}Cs and heavy metal levels in mountain soil taken from Chochołowska Valley, which revealed great variability in their concentration. The results show considerably small amounts of radionuclides 137Cs^{137}Cs and 40K^{40}K in the soils. Larger amounts of those elements can be found in the organic surface horizons of the soils. The evaluation of the content of those elements must be based on the bulk density analysis of the soil

    Novel Interconnections in Lipid Metabolism Revealed by Overexpression of Sphingomyelin Synthase-1

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    This study investigates the consequences of elevating sphingomyelin synthase 1 (SMS1) activity, which generates the main mammalian sphingolipid, sphingomyelin. HepG2 cells stably transfected with SMS1 (HepG2-SMS1) exhibit elevated enzyme activity in vitro and increased sphingomyelin content (mainly C22:0- and C24:0-sphingomyelin) but lower hexosylceramide (Hex-Cer) levels. HepG2-SMS1 cells have fewer triacylglycerols than controls but similar diacylglycerol acyltransferase activity, triacylglycerol secretion, and mitochondrial function. Treatment with 1 mm palmitate increases de novo ceramide synthesis in both cell lines to a similar degree, causing accumulation of C16:0-ceramide (and some C18:0-, C20:0-, and C22:0-ceramides) as well as C16:0- and C18:0-Hex-Cers. In these experiments, the palmitic acid is delivered as a complex with delipidated BSA (2:1, mol/mol) and does not induce significant lipotoxicity. Based on precursor labeling, the flux through SM synthase also increases, which is exacerbated in HepG2-SMS1 cells. In contrast, palmitate-induced lipid droplet formation is significantly reduced in HepG2-SMS1 cells. [14C]Choline and [3H]palmitate tracking shows that SMS1 overexpression apparently affects the partitioning of palmitate-enriched diacylglycerol between the phosphatidylcholine and triacylglycerol pathways, to the benefit of the former. Furthermore, triacylglycerols from HepG2-SMS1 cells are enriched in polyunsaturated fatty acids, which is indicative of active remodeling. Together, these results delineate novel metabolic interactions between glycerolipids and sphingolipids

    Ogle-2018-blg-0677lb: A super earth near the galactic bulge

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    We report the analysis of the microlensing event OGLE-2018-BLG-0677. A small feature in the light curve of the event leads to the discovery that the lens is a star-planet system. Although there are two degenerate solutions that could not be distinguished for this event, both lead to a similar planet-host mass ratio. We perform a Bayesian analysis based on a Galactic model to obtain the properties of the system and find that the planet corresponds to a super-Earth/sub-Neptune with a mass Mplanet=3.962.66+5.88MM_{\mathrm{planet}} = {3.96}^{+5.88}_{-2.66}\mathrm{M_\oplus}. The host star has a mass Mhost=0.120.08+0.14M M_{\mathrm{host}} = {0.12}^{+0.14}_{-0.08}\mathrm{M_\odot}. The projected separation for the inner and outer solutions are 0.630.17+0.20{0.63}^{+0.20}_{-0.17}~AU and 0.720.19+0.23{0.72}^{+0.23}_{-0.19}~AU respectively. At Δχ2=χ2(1L1S)χ2(2L1S)=46\Delta\chi^2=\chi^2({\rm 1L1S})-\chi^2({\rm 2L1S})=46, this is by far the lowest Δχ2\Delta\chi^2 for any securely-detected microlensing planet to date, a feature that is closely connected to the fact that it is detected primarily via a "dip" rather than a "bump".Comment: 15 page, 12 figures, Published in A

    High-E_T dijet photoproduction at HERA

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    The cross section for high-E_T dijet production in photoproduction has been measured with the ZEUS detector at HERA using an integrated luminosity of 81.8 pb-1. The events were required to have a virtuality of the incoming photon, Q^2, of less than 1 GeV^2 and a photon-proton centre-of-mass energy in the range 142 < W < 293 GeV. Events were selected if at least two jets satisfied the transverse-energy requirements of E_T(jet1) > 20 GeV and E_T(jet2) > 15 GeV and pseudorapidity requirements of -1 < eta(jet1,2) < 3, with at least one of the jets satisfying -1 < eta(jet) < 2.5. The measurements show sensitivity to the parton distributions in the photon and proton and effects beyond next-to-leading order in QCD. Hence these data can be used to constrain further the parton densities in the proton and photon.Comment: 36 pages, 13 figures, 20 tables, including minor revisions from referees. Accepted by Phys. Rev.

    Prospects for K+π+ννˉK^+ \to \pi^+ \nu \bar{ \nu } at CERN in NA62

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    The NA62 experiment will begin taking data in 2015. Its primary purpose is a 10% measurement of the branching ratio of the ultrarare kaon decay K+π+ννˉK^+ \to \pi^+ \nu \bar{ \nu }, using the decay in flight of kaons in an unseparated beam with momentum 75 GeV/c.The detector and analysis technique are described here.Comment: 8 pages for proceedings of 50 Years of CP

    OGLE-2018-BLG-0022: First Prediction of an Astrometric Microlensing Signal from a Photometric Microlensing Event

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    In this work, we present the analysis of the binary microlensing event OGLE-2018-BLG-0022 that is detected toward the Galactic bulge field. The dense and continuous coverage with the high-quality photometry data from ground-based observations combined with the space-based {\it Spitzer} observations of this long time-scale event enables us to uniquely determine the masses M1=0.40±0.05 MM_1=0.40 \pm 0.05~M_\odot and M2=0.13±0.01 MM_2=0.13\pm 0.01~M_\odot of the individual lens components. Because the lens-source relative parallax and the vector lens-source relative proper motion are unambiguously determined, we can likewise unambiguously predict the astrometric offset between the light centroid of the magnified images (as observed by the {\it Gaia} satellite) and the true position of the source. This prediction can be tested when the individual-epoch {\it Gaia} astrometric measurements are released.Comment: 10 pages, 10 figures, 4 table

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

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    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

    Effect of base–acid properties of the mixtures of water with methanol on the solution enthalpy of selected cyclic ethers in this mixture at 298.15 K

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    The enthalpies of solution of cyclic ethers: 1,4- dioxane, 12-crown-4 and 18-crown-6 in the mixture of water and methanol have been measured within the whole mole fraction range at T = 298.15 K. Based on the obtained data, the effect of base–acid properties of water– methanol mixtures on the solution enthalpy of cyclic ethers in these mixtures has been analyzed. The solution enthalpy of cyclic ethers depends on acid properties of water– methanol mixtures in the range of high and medium water contents in the mixture. Based on the analysis performed, it can be assumed that in the mixtures of high methanol contents, cyclic ethe
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