577 research outputs found

    Kinetic and thermodynamic analysis of leech-derived tryptase inhibitor interaction with bovine tryptase and bovine trypsin

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    The interaction of leech-derived tryptase inhibitor (LDTI) with bovine liver capsule tryptase (BLCT) and bovine trypsin has been studied using both thermodynamic and kinetic approaches. Several differences were detected: (i) the equilibrium affinity of LDTI for BLCT (K-a = 8.9 x 10(5) M-1) is about 600-fold lower than that for bovine trypsin (K-a = 5.1 x 10(8) M-1); (ii) LDTI behaves as a purely non-competitive inhibitor of BLCT, while it is a purely competitive inhibitor of bovine trypsin. These functional data are compared with those previously reported for the LDTI binding to human tryptase, where tight inhibition occurs at two of the four active sites of the tetramer (K-a = 7.1 x 10(8) M-1). Amino acid sequence alignment of BLCT, human beta II-tryptase and bovine trypsin allows us to infer some possible structural basis for the observed functional differences

    Validation of a microsimulation of the port of Dover

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    Modelling and simulating the traffic of heavily used but secure environments such as seaports and airports is of increasing importance. Errors made when simulating these environments can have long standing economic, social and environmental implications. This paper discusses issues and problems that may arise when designing a simulation strategy. Data for the Port is presented, methods for lightweight vehicle assessment that can be used to calibrate and validate simulations are also discussed along with a diagnosis of overcalibration issues. We show that decisions about where the intelligence lies in a system has important repercussions for the reliability of system statistics. Finally, conclusions are drawn about how microsimulations can be moved forward as a robust planning tool for the 21st century

    Recent progress in the quantitative validation of JOREK simulations of ELMs in JET

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    Future devices like JT-60SA, ITER and DEMO require quantitative predictions of pedestal density and temperature levels, as well as inter-ELM and ELM divertor heat fluxes, in order to improve global confinement capabilities while preventing divertor erosion/melting in the planning of future experiments. Such predictions can be obtained from dedicated pedestal models like EPED, and from non-linear MHD codes like JOREK, for which systematic validation against current experiments is necessary. In this paper, we show progress in the quantitative validation of the JOREK code using JET simulations. Results analyse the impact of diamagnetic terms on the dynamics and size of the ELMs, and evidence is provided that the onset of type-I ELMs is not governed by linear MHD stability alone, but that a nonlinear threshold could be responsible for large MHD events at the plasma edge.This work has been carried out within the framework of the EUROfusion Consortium and has received funding from the Euratom research and training programme 2014–2018 under grant agreement No 633053, and from the RCUK Energy Programme (grant number EP/I501045). To obtain further information on the data and models underlying this paper please contact PublicationsManagerccfe.ac.uk. This work used the HELIOS supercomputer (IFERC-CSC), Japan, under the Broader Approach collaboration, implemented by Fusion for Energy and JAEA. The views and opinions expressed herein do not necessarily reflect those of the European Commission or the ITER Organization. The HEC ARCHER computer (UK), as part of the Plasma HEC Consortium EPSRC grant EP/L000237/1, and the MARCONI computer at CINECA in Italy, were also used.Peer ReviewedPostprint (author's final draft

    Measurement of single pi0 production in neutral current neutrino interactions with water by a 1.3 GeV wide band muon neutrino beam

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    Neutral current single pi0 production induced by neutrinos with a mean energy of 1.3 GeV is measured at a 1000 ton water Cherenkov detector as a near detector of the K2K long baseline neutrino experiment. The cross section for this process relative to the total charged current cross section is measured to be 0.064 +- 0.001 (stat.) +- 0.007 (sys.). The momentum distribution of produced pi0s is measured and is found to be in good agreement with an expectation from the present knowledge of the neutrino cross sections.Comment: 6 pages, 4 figures, Submitted to Phys. Lett.

    Search for Neutral Q-balls in Super-Kamiokande II

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    A search for Q-balls induced groups of successive contained events has been carried out in Super-Kamiokande II with 541.7 days of live time. Neutral Q-balls would emit pions when colliding with nuclei, generating a signal of successive contained pion events along a track. No candidate for successive contained event groups has been found in Super-Kamiokande II, so upper limits on the possible flux of such Q-balls have been obtained.Comment: 5 pages, 5 figures, Submitted to Phys. Lett.

    Estimating the frequency of volcanic ash clouds over northern Europe

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    Fine ash produced during explosive volcanic eruptions can be dispersed over a vast area, where it poses a threat to aviation, human health and infrastructure. Here, we focus on northern Europe, which lies in the principal transport direction for volcanic ash from Iceland, one of the most active volcanic regions in the world. We interrogate existing and newly produced geological and written records of past ash fallout over northern Europe in the last 1000 years and estimate the mean return (repose) interval of a volcanic ash cloud over the region to be 44 ± 7 years. We compare tephra records from mainland northern Europe, Great Britain, Ireland and the Faroe Islands, with records of proximal Icelandic volcanism and suggest that an Icelandic eruption with a Volcanic Explosivity Index rating (VEI) ≄ 4 and a silicic magma composition presents the greatest risk of producing volcanic ash that can reach northern Europe. None of the ash clouds in the European record which have a known source eruption are linked to a source eruption with VEI < 4. Our results suggest that ash clouds are more common over northern Europe than previously proposed and indicate the continued threat of ash deposition across northern Europe from eruptions of both Icelandic and North American volcanoes

    Photoproduction of D∗±D^{*\pm} mesons associated with a leading neutron

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    The photoproduction of D∗±(2010)D^{*\pm} (2010) mesons associated with a leading neutron has been observed with the ZEUS detector in epep collisions at HERA using an integrated luminosity of 80 pb−1^{-1}. The neutron carries a large fraction, {xL>0.2x_L>0.2}, of the incoming proton beam energy and is detected at very small production angles, {Ξn<0.8\theta_n<0.8 mrad}, an indication of peripheral scattering. The D∗D^* meson is centrally produced with pseudorapidity {∣η∣1.9|\eta| 1.9 GeV}, which is large compared to the average transverse momentum of the neutron of 0.22 GeV. The ratio of neutron-tagged to inclusive D∗D^* production is 8.85±0.93(stat.)−0.61+0.48(syst.)%8.85\pm 0.93({\rm stat.})^{+0.48}_{-0.61}({\rm syst.})\% in the photon-proton center-of-mass energy range {130<W<280130 <W<280 GeV}. The data suggest that the presence of a hard scale enhances the fraction of events with a leading neutron in the final state.Comment: 28 pages, 4 figures, 2 table

    Measurement of beauty production in deep inelastic scattering at HERA

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    The beauty production cross section for deep inelastic scattering events with at least one hard jet in the Breit frame together with a muon has been measured, for photon virtualities Q^2 > 2 GeV^2, with the ZEUS detector at HERA using integrated luminosity of 72 pb^-1. The total visible cross section is sigma_b-bbar (ep -> e jet mu X) = 40.9 +- 5.7 (stat.) +6.0 -4.4 (syst.) pb. The next-to-leading order QCD prediction lies about 2.5 standard deviations below the data. The differential cross sections are in general consistent with the NLO QCD predictions; however at low values of Q^2, Bjorken x, and muon transverse momentum, and high values of jet transverse energy and muon pseudorapidity, the prediction is about two standard deviations below the data.Comment: 18 pages, 4 figure

    Search for lepton-flavor violation at HERA

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    A search for lepton-flavor-violating interactions ep→ΌXe p \to \mu X and ep→τXe p\to \tau X has been performed with the ZEUS detector using the entire HERA I data sample, corresponding to an integrated luminosity of 130 pb^{-1}. The data were taken at center-of-mass energies, s\sqrt{s}, of 300 and 318 GeV. No evidence of lepton-flavor violation was found, and constraints were derived on leptoquarks (LQs) that could mediate such interactions. For LQ masses below s\sqrt{s}, limits were set on λeq1ÎČℓq\lambda_{eq_1} \sqrt{\beta_{\ell q}}, where λeq1\lambda_{eq_1} is the coupling of the LQ to an electron and a first-generation quark q1q_1, and ÎČℓq\beta_{\ell q} is the branching ratio of the LQ to the final-state lepton ℓ\ell (ÎŒ\mu or τ\tau) and a quark qq. For LQ masses much larger than s\sqrt{s}, limits were set on the four-fermion interaction term λeqαλℓqÎČ/MLQ2\lambda_{e q_\alpha} \lambda_{\ell q_\beta} / M_{\mathrm{LQ}}^2 for LQs that couple to an electron and a quark qαq_\alpha and to a lepton ℓ\ell and a quark qÎČq_\beta, where α\alpha and ÎČ\beta are quark generation indices. Some of the limits are also applicable to lepton-flavor-violating processes mediated by squarks in RR-Parity-violating supersymmetric models. In some cases, especially when a higher-generation quark is involved and for the process ep→τXe p\to \tau X , the ZEUS limits are the most stringent to date.Comment: 37 pages, 10 figures, Accepted by EPJC. References and 1 figure (Fig. 6) adde
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