819 research outputs found
Controlling the polarisation correlation of photon pairs from a charge-tuneable quantum dot
Correlation between the rectilinear polarisations of the photons emitted from
the biexciton decay in a single quantum dot is investigated in a device which
allows the charge-state of the dot to be controlled. Optimising emission from
the neutral exciton states maximises the operating efficiency of the biexciton
decay. This is important for single dot applications such as a triggered source
of entangled photons. As the bias on the device is reduced correlation between
the two photons is found to fall dramatically as emission from the negatively
charged exciton becomes significant. Lifetime measurements demonstrate that
electronic spin-scattering is the likely cause.Comment: 3 figure
Quantum Memories. A Review based on the European Integrated Project "Qubit Applications (QAP)"
We perform a review of various approaches to the implementation of quantum
memories, with an emphasis on activities within the quantum memory sub-project
of the EU Integrated Project "Qubit Applications". We begin with a brief
overview over different applications for quantum memories and different types
of quantum memories. We discuss the most important criteria for assessing
quantum memory performance and the most important physical requirements. Then
we review the different approaches represented in "Qubit Applications" in some
detail. They include solid-state atomic ensembles, NV centers, quantum dots,
single atoms, atomic gases and optical phonons in diamond. We compare the
different approaches using the discussed criteria.Comment: 22 pages, 12 figure
Anti-inflammatory and anti-invasive effects of α-melanocyte-stimulating hormone in human melanoma cells
Alpha-melanocyte stimulating hormone (alpha-MSH) is known to have pleiotrophic functions including pigmentary, anti-inflammatory, antipyretic and immunoregulatory roles in the mammalian body. It is also reported to influence melanoma invasion with levels of alpha-, beta- and gamma-MSH correlated clinically with malignant melanoma development, but other studies suggest alpha-MSH acts to retard invasion. In the present study, we investigated the action of alpha-MSH on three human melanoma cell lines (HBL, A375-SM and C8161) differing in metastatic potential. alpha-melanocyte-simulating hormone reduced invasion through fibronectin and also through a human reconstructed skin composite model for the HBL line, and inhibited proinflammatory cytokine-stimulated activation of the NF-kappaB transcription factor. However, A375-SM and C8161 cells did not respond to alpha-MSH. Immunofluorescent microscopy and Western blotting identified melanocortin-1 receptor (MC-1R) expression for all three lines and MC-2R on HBL and A375-SM lines. Receptor binding identified a similar affinity for alpha-MSH for all three lines with the highest number of binding sites on HBL cells. Only the HBL melanoma line demonstrated a detectable cyclic adenosine monophosphate (cAMP) response to alpha-MSH, although all three lines responded to acute alpha-MSH addition (+(-)-N(6)-(2-phenylisopropyl)-adenosine (PIA)) with an elevation in intracellular calcium. The nonresponsive lines displayed MC-1R polymorphisms (C8161, Arg (wt) 151/Cys 151; A375-SM, homozygous Cys 151), whereas the HBL line was wild type. Stable transfection of the C8161 line with wild-type MC-1R produced cells whose invasion was significantly inhibited by alpha-MSH. From this data, we conclude that alpha-MSH can reduce melanoma cell invasion and protect cells against proinflammatory cytokine attack in cells with the wild-type receptor (HBL).Journal ArticleResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe
Dissolved noble gases and stable isotopes as tracers of preferential fluid flow along faults in the Lower Rhine Embayment, Germany
Groundwater in shallow unconsolidated sedimentary aquifers close to the Bornheim fault in the Lower Rhine Embayment (LRE), Germany, has relatively low ÎŽ2H and ÎŽ18O values in comparison to regional modern groundwater recharge, and 4He concentrations up to 1.7 Ă 10â4 cm3 (STP) gâ1 ± 2.2 % which is approximately four orders of magnitude higher than expected due to solubility equilibrium with the atmosphere. Groundwater age dating based on estimated in situ production and terrigenic flux of helium provides a groundwater residence time of âŒ107 years. Although fluid exchange between the deep basal aquifer system and the upper aquifer layers is generally impeded by confining clay layers and lignite, this studyâs geochemical data suggest, for the first time, that deep circulating fluids penetrate shallow aquifers in the locality of fault zones, implying that sub-vertical fluid flow occurs along faults in the LRE. However, large hydraulic-head gradients observed across many faults suggest that they act as barriers to lateral groundwater flow. Therefore, the geochemical data reported here also substantiate a conduit-barrier model of fault-zone hydrogeology in unconsolidated sedimentary deposits, as well as corroborating the concept that faults in unconsolidated aquifer systems can act as loci for hydraulic connectivity between deep and shallow aquifers. The implications of fluid flow along faults in sedimentary basins worldwide are far reaching and of particular concern for carbon capture and storage (CCS) programmes, impacts of deep shale gas recovery for shallow groundwater aquifers, and nuclear waste storage sites where fault zones could act as potential leakage pathways for hazardous fluids
Drawing to Remember: External Support of Older Adultsâ Eyewitness Performance
Although healthy aging is accompanied by a general decline in memory functioning, environmental support at retrieval can improve older adultsâ (+65 years) episodic remembering. Despite those over the age of 65years representing a growing proportion of the population, few environmental retrieval support methods have been empirically evaluated for use with older witnesses and victims of crime. Here, the efficacy of a novel retrieval technique, the Sketch Mental Reinstatement of Context, is compared with a standard Mental Reinstatement of Context and a no support control (Control). Fifty-one participants witnessed an unexpected live event, and 48 hours later were interviewed using one of three aforementioned techniques. In line with predictions emanating from cognitive theories of aging and the environmental support hypothesis, participants in the Sketch Mental Reinstatement of Context condition recalled significantly more correct information and fewer inaccurate items. The Sketch Mental Reinstatement of Context technique appears to scaffold memory retrieval in an age-appropriate manner during a post-event interview, possibly by encouraging more effortful retrieval and reducing dual-task load. As such, this procedure offers an effective alternative to current approaches, adding to the toolbox of techniques available to forensic and other interviewers
Measurements of neutrino oscillation in appearance and disappearance channels by the T2K experiment with 6.6 x 10(20) protons on target
111 pages, 45 figures, submitted to Physical Review D. Minor revisions to text following referee comments111 pages, 45 figures, submitted to Physical Review D. Minor revisions to text following referee comments111 pages, 45 figures, submitted to Physical Review D. Minor revisions to text following referee commentsWe thank the J-PARC staff for superb accelerator performance and the CERN NA61/SHINE Collaboration for providing valuable particle production data. We acknowledge the support of MEXT, Japan; NSERC, NRC, and CFI, Canada; CEA and CNRS/IN2P3, France; DFG, Germany; INFN, Italy; National Science Centre (NCN), Poland; RSF, RFBR and MES, Russia; MINECO and ERDF funds, Spain; SNSF and SER, Switzerland; STFC, UK; and the U. S. Deparment of Energy, USA. We also thank CERN for the UA1/NOMAD magnet, DESY for the HERA-B magnet mover system, NII for SINET4, the WestGrid and SciNet consortia in Compute Canada, GridPP, UK, and the Emerald High Performance Computing facility in the Centre for Innovation, UK. In addition, participation of individual researchers and institutions has been further supported by funds from ERC (FP7), EU; JSPS, Japan; Royal Society, UK; and DOE Early Career program, USA
Measurement of the electron neutrino charged-current interaction rate on water with the T2K ND280 pi(0) detector
10 pages, 6 figures, Submitted to PRDhttp://journals.aps.org/prd/abstract/10.1103/PhysRevD.91.112010© 2015 American Physical Society11 pages, 6 figures, as accepted to PRD11 pages, 6 figures, as accepted to PRD11 pages, 6 figures, as accepted to PR
Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector
The inclusive and dijet production cross-sections have been measured for jets
containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass
energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The
measurements use data corresponding to an integrated luminosity of 34 pb^-1.
The b-jets are identified using either a lifetime-based method, where secondary
decay vertices of b-hadrons in jets are reconstructed using information from
the tracking detectors, or a muon-based method where the presence of a muon is
used to identify semileptonic decays of b-hadrons inside jets. The inclusive
b-jet cross-section is measured as a function of transverse momentum in the
range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet
cross-section is measured as a function of the dijet invariant mass in the
range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets
and the angular variable chi in two dijet mass regions. The results are
compared with next-to-leading-order QCD predictions. Good agreement is observed
between the measured cross-sections and the predictions obtained using POWHEG +
Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet
cross-section. However, it does not reproduce the measured inclusive
cross-section well, particularly for central b-jets with large transverse
momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final
version published in European Physical Journal
Observation of associated near-side and away-side long-range correlations in âsNN=5.02ââTeV proton-lead collisions with the ATLAS detector
Two-particle correlations in relative azimuthal angle (ÎÏ) and pseudorapidity (Îη) are measured in âsNN=5.02ââTeV p+Pb collisions using the ATLAS detector at the LHC. The measurements are performed using approximately 1ââÎŒb-1 of data as a function of transverse momentum (pT) and the transverse energy (ÎŁETPb) summed over 3.1<η<4.9 in the direction of the Pb beam. The correlation function, constructed from charged particles, exhibits a long-range (2<|Îη|<5) ânear-sideâ (ÎÏâŒ0) correlation that grows rapidly with increasing ÎŁETPb. A long-range âaway-sideâ (ÎÏâŒÏ) correlation, obtained by subtracting the expected contributions from recoiling dijets and other sources estimated using events with small ÎŁETPb, is found to match the near-side correlation in magnitude, shape (in Îη and ÎÏ) and ÎŁETPb dependence. The resultant ÎÏ correlation is approximately symmetric about Ï/2, and is consistent with a dominant cosâĄ2ÎÏ modulation for all ÎŁETPb ranges and particle pT
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