832 research outputs found

    K p formation experiment

    Get PDF

    The influence of non-imaging detector design on heralded ghost-imaging and ghost-diffraction examined using a triggered ICCD came

    Get PDF
    Ghost imaging and ghost diffraction can be realized by using the spatial correlations between signal and idler photons produced by spontaneous parametric down-conversion. If an object is placed in the signal (idler) path, the spatial correlations between the transmitted photons as measured by a single, non-imaging, “bucket” detector and a scanning detector placed in the idler (signal) path can reveal either the image or diffraction pattern of the object, whereas neither detector signal on its own can. The details of the bucket detector, such as its collection area and numerical aperture, set the number of transverse modes supported by the system. For ghost imaging these details are less important, affecting mostly the sampling time required to produce the image. For ghost diffraction, however, the bucket detector must be filtered to a single, spatially coherent mode. We examine this difference in behavour by using either a multi-mode or single-mode fibre to define the detection aperture. Furthermore, instead of a scanning detector we use a heralded camera so that the image or diffraction pattern produced can be measured across the full field of view. The importance of a single mode detection in the observation of ghost diffraction is equivalent to the need within a classical diffraction experiment to illuminate the aperture with a spatially coherent mode

    The feasibility of a randomised controlled trial of Dyadic Developmental Psychotherapy

    Get PDF
    Background: Maltreated children have significant and complex problems which clinicians find difficult to diagnose and treat. Previous US pilot work suggests that Dyadic Developmental Psychotherapy (DDP) may be effective; however, rigorous evidence from a randomised controlled trial (RCT) is lacking. The purpose of this study is to establish the feasibility of an RCT of DDP by exploring the ways that DDP is operating across different UK sites and the impacts of current practice on the potential set-up of an RCT. Methods: Qualitative methods (interviews, focus groups and teleconferences) were used to explore trial feasibility with therapists and service managers from teams implementing both DDP and possible control interventions. Data were analysed thematically and related to various aspects of trial design. Results: DDP was commonly regarded as having a particular congruence with the complexity of maltreatment-associated problems and a common operating model of DDP was evident across sites. A single control therapy was harder to establish, however, and it is likely to be a non-specific and context-dependent intervention/s offered within mainstream Child and Adolescent Mental Health Services (CAMHS). Because a ‘gold standard’ Treatment as Usual (TAU) does not currently exist, randomisation between DDP and TAU (CAMHS) therefore looks feasible and ethical. The nature of family change during DDP was regarded as multi-faceted, non-linear and relationship-based. Assessment tools need to be carefully considered in terms of their ability to capture change that covers both individual child and family-based functioning. Conclusions: An RCT of DDP is feasible and timely. This study has demonstrated widespread interest, support and engagement regarding an RCT and permissions have been gained from sites that have shown readiness to participate. As maltreated children are among the most vulnerable in society, and as there are currently no treatments with RCT evidence, such a trial would be a major advance in the field

    Elemental patterns in Ni hyperaccumulating and non-hyperaccumulating ultramafic soil populations of Senecio coronatus

    Get PDF
    AbstractNickel hyperaccumulation can defend plants against herbivores and pathogens. However, variability in plant tissue elemental concentrations in space and time will influence the effectiveness of this defense. We investigated a South African Ni hyperaccumulator, Senecio coronatus Thunb. (Harv.), for variation in nine elements (Ni plus Ca, Cu, Fe, K, Mg, Mn, P and Zn) between populations and between above-ground and below-ground plant organs (leaves, roots). Plant material was collected from four populations growing on ultramafic soils in the vicinity of Badplaas, Mpumalanga Province, South Africa. Concentrations of Ca, Cu, Fe, K, Mg, Mn, Ni, P and Zn were determined in dry-ashed samples. Two-way analysis of variance of data for each element revealed considerable variation in S. coronatus plant chemistry. Leaf concentrations of all elements except Cu were generally greater than root concentrations. Population-level variation was found for Ca, Fe, Mn, P, Ni and Zn, and of these all but P showed significant two-way interactions as well. Significant positive correlations were found between some pairs of elements: in hyperaccumulator roots (Ni–Ca, K–Mg), non-hyperaccumulator roots (Fe–Mn, Fe–Zn, Fe–Cu, Cu–Zn), hyperaccumulator leaves (P–Mg, P–Fe, P–Mn, Fe–Mg) and non-hyperaccumulator leaves (P–Mn, P–Ca, Ca–Mn). Two populations hyperaccumulated Ni in leaves (means of 12,000 and 8800 Όg Ni/g) whereas the others did not (means of 120 and 130 Όg Ni/g). Such extreme population-level variation in Ni accumulation ability is unusual among Ni hyperaccumulator species: its physiological basis and possible consequences for plant elemental defense deserve further investigation

    Protocol for the economic evaluation of a complex intervention to improve the mental health of maltreated infants and children in foster care in the UK (The BeST? services trial)

    Get PDF
    Introduction: Children who have experienced abuse and neglect are at increased risk of mental and physical health problems throughout life. This places an enormous burden on individuals, families and society in terms of health services, education, social care and judiciary sectors. Evidence suggests that early intervention can mitigate the negative consequences of child maltreatment, exerting long-term positive effects on the health of maltreated children entering foster care. However, evidence on cost-effectiveness of such complex interventions is limited. This protocol describes the first economic evaluation of its kind in the UK. Methods and analysis: An economic evaluation alongside the Best Services Trial (BeST?) has been prospectively designed to identify, measure and value key resource and outcome impacts arising from the New Orleans intervention model (NIM) (an infant mental health service) compared with case management (CM) (enhanced social work services as usual). A within-trial economic evaluation and long-term model from a National Health Service/Personal Social Service and a broader societal perspective will be undertaken alongside the National Institute for Health Research (NIHR)–Public Health Research Unit (PHRU)-funded randomised multicentre BeST?. BeST? aims to evaluate NIM compared with CM for maltreated children entering foster care in a UK context. Collection of Paediatric Quality of Life Inventory (PedsQL) and the recent mapping of PedsQL to EuroQol-5-Dimensions (EQ-5D) will facilitate the estimation of quality-adjusted life years specific to the infant population for a cost–utility analysis. Other effectiveness outcomes will be incorporated into a cost-effectiveness analysis (CEA) and cost-consequences analysis (CCA). A long-term economic model and multiple economic evaluation frameworks will provide decision-makers with a comprehensive, multiperspective guide regarding cost-effectiveness of NIM. The long-term population health economic model will be developed to synthesise trial data with routine linked data and key government sector parameters informed by literature. Methods guidance for population health economic evaluation will be adopted (lifetime horizon, 1.5% discount rate for costs and benefits, CCA framework, multisector perspective). Ethics and dissemination: Ethics approval was obtained by the West of Scotland Ethics Committee. Results of the main trial and economic evaluation will be submitted for publication in a peer-reviewed journal as well as published in the peer-reviewed NIHR journals library (Public Health Research Programme). Trial registration number: NCT02653716; Pre-results

    A preliminary study of the role of nickel in enhancing flowering of the nickel hyperaccumulating plant \u3ci\u3eAlyssum inflatum\u3c/i\u3e NyĂĄr. (Brassicaceae)

    Get PDF
    Alyssum inflatum is a native of serpentine soils and is able to hyperaccumulate nickel (Ni), but the importance of Ni to reproduction in the species is unknown. We investigated if reproductive fitness is enhanced by Ni in the growth medium, and included a treatment involving a relatively high level of Mg to provide a comparison with elevated levels of another metal. Seedlings were grown in a modified Hoagland solution culture in an inert medium of Perlite and were treated with Ni (100 ÎŒM), a high concentration of Mg (5 mM), or under control conditions (solution culture without Ni or the addition of high Mg) for 14 months. We documented survival, as well as the proportion of individuals that flowered. We also quantified flower production as an indicator of plant fitness. Survival was not affected by treatment (87–90% for all treatments), but significantly more Ni-treated plants (63%) flowered compared with Mg-treated (19%) or control plants (12%). In addition, inflorescences per plant, inflorescence length, and number of open flowers per inflorescence were all significantly greater for Ni-treated plants relative to plants from the other treatments. Although high levels of Ni are not essential for growth and reproduction of the species, we suggest that Ni stimulates flowering in A. inflatum and may result in greater fitness for the species on serpentine soils

    Dimensional Crossover in the Effective Second Harmonic Generation of Films of Random Dielectrics

    Full text link
    The effective nonlinear response of films of random composites consisting of a binary composite with nonlinear particles randomly embedded in a linear host is theoretically and numerically studied. A theoretical expression for the effective second harmonic generation susceptibility, incorporating the thickness of the film, is obtained by combining a modified effective-medium approximation with the general expression for the effective second harmonic generation susceptibility in a composite. The validity of the thoretical results is tested against results obtained by numerical simulations on random resistor networks. Numerical results are found to be well described by our theory. The result implies that the effective-medium approximation provides a convenient way for the estimation of the nonlinear response in films of random dielectrics.Comment: 9 pages, 2 figures; accepted for publication in Phys. Rev.

    Kosterlitz Thouless Universality in Dimer Models

    Full text link
    Using the monomer-dimer representation of strongly coupled U(N) lattice gauge theories with staggered fermions, we study finite temperature chiral phase transitions in (2+1) dimensions. A new cluster algorithm allows us to compute monomer-monomer and dimer-dimer correlations at zero monomer density (chiral limit) accurately on large lattices. This makes it possible to show convincingly, for the first time, that these models undergo a finite temperature phase transition which belongs to the Kosterlitz-Thouless universality class. We find that this universality class is unaffected even in the large N limit. This shows that the mean field analysis often used in this limit breaks down in the critical region.Comment: 4 pages, 4 figure

    A preliminary study of the role of nickel in enhancing flowering of the nickel hyperaccumulating plant Alyssum inflatum NyĂĄr. (Brassicaceae)

    Get PDF
    Alyssum inflatum is a native of serpentine soils and is able to hyperaccumulate nickel (Ni), but the importance of Ni to reproduction in the species is unknown. We investigated if reproductive fitness is enhanced by Ni in the growth medium, and included a treatment involving a relatively high level of Mg to provide a comparison with elevated levels of another metal. Seedlings were grown in a modified Hoagland solution culture in an inertmediumof Perlite andwere treatedwith Ni (100 ÎŒM), a high concentration ofMg (5mM), or under control conditions (solution culture without Ni or the addition of high Mg) for 14 months.We documented survival, as well as the proportion of individuals that flowered.We also quantified flower production as an indicator of plant fitness. Survival was not affected by treatment (87–90% for all treatments), but significantly more Ni-treated plants (63%) flowered compared with Mg-treated (19%) or control plants (12%). In addition, inflorescences per plant, inflorescence length, and number of open flowers per inflorescence were all significantly greater for Nitreated plants relative to plants fromthe other treatments. Although high levels of Ni are not essential for growth and reproduction of the species, we suggest that Ni stimulates flowering in A. inflatum and may result in greater fitness for the species on serpentine soils

    Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events

    Get PDF
    The B0B^0-Bˉ0\bar B^0 oscillation frequency has been measured with a sample of 23 million \B\bar B pairs collected with the BABAR detector at the PEP-II asymmetric B Factory at SLAC. In this sample, we select events in which both B mesons decay semileptonically and use the charge of the leptons to identify the flavor of each B meson. A simultaneous fit to the decay time difference distributions for opposite- and same-sign dilepton events gives Δmd=0.493±0.012(stat)±0.009(syst)\Delta m_d = 0.493 \pm 0.012{(stat)}\pm 0.009{(syst)} ps−1^{-1}.Comment: 7 pages, 1 figure, submitted to Physical Review Letter
    • 

    corecore