116 research outputs found

    Water Quality, nutrients and the European Union’s Water Framework Directive in a lowland agricultural region: Suffolk, south-east England.

    Get PDF
    The water quality of 13 rivers in the lowland, agricultural county of Suffolk is investigated using routine monitoring data for the period 1981 to 2006 collected by the Environment Agency of England and Wales (EA), and its predecessors, with particular emphasis on phosphorus (as total reactive phosphorus, TRP) and total (dissolved and particulate) oxidised nitrogen (TOxN – predominantly nitrate NO3). Major ion and flow data are used to outline fundamental hydrochemical characteristics related to the groundwater provenance of base-flow waters. Relative load contributions from point and diffuse sources are approximated using Load Apportionment Modelling for both TRP and TOxN where concurrent flow and concentration data are available. Analyses indicate a mixture of point and diffuse sources of TRP, with the former being dominant during low flow periods, while for TOxN diffuse sources dominate. Out of 59 sites considered, 53 (90%) were found to have annual average TRP concentrations greater than 0.05 mg P l-1, and 36 (61%) had average concentrations over 0.120 mg P l-1, the upper thresholds for ‘High’ and ‘Good’ ecological status, respectively. Correspondingly, for TOxN, most of the rivers are already within 70% of the 11.3 mg N l-1 threshold, with two rivers (Wang and Ore) being consistently greater than this. It is suggested that the major challenge is to characterise and control point-source TRP inputs which, being predominant during the late spring and summer low-flow period, coincide with the peak of primary biological production, thus presenting the major challenge to achieving ‘good’ ecological status under the Water Framework Directive. Results show that considerable effort is still required to ensure appropriate management and develop tools for decision-support

    Phenomenological Analysis of B->PP Decays with QCD Factorization

    Full text link
    In this paper, we study nonleptonic charmless B decays to two light pseudoscalar mesons within the frame of QCD factorization, including the contributions from the chirally enhanced power corrections and weak annihilation. Predictions for the CP-averaged branching ratios and CP-violating asymmetries are given. Within the reasonable range of the parameters, we find that our predictions for the branching ratios of B -> PP are consistent with the present experimental data. But because of the logarithmic divergences at the endpoints in the hard spectator scatterings and weak annihilation, there are still large uncertainties in these predictions.Comment: 34 pages, 5 figures. to appear in PR

    Lattice Study of the Decay B^0-bar -> rho^+ l^- nu_l-bar: Model-Independent Determination of |V_{ub}|

    Full text link
    We present results of a lattice computation of the vector and axial-vector current matrix elements relevant for the semileptonic decay B^0-bar -> rho^+ l^- nu_l-bar. The computations are performed in the quenched approximation of lattice QCD on a 24^3 x 48 lattice at beta = 6.2, using an O(a) improved fermionic action. Our principal result is for the differential decay rate, dGamma/dq^2, for the decay B^0-bar -> rho^+ l^- nu_l-bar in a region beyond the charm threshold, allowing a model-independent extraction of |V_{ub}| from experimental measurements. Heavy quark symmetry relations between radiative and semileptonic decays of B-bar mesons into light vector mesons are also discussed.Comment: 22 pages LaTeX-209 (dependent on settings in a4.sty), 23 PostScript figures included with epsf.sty. Complete PostScript file including figures available at http://wwwhep.phys.soton.ac.uk/hepwww/papers/shep9518

    Experimental Tests of Factorization in Charmless Non-Leptonic Two-Body B Decays

    Get PDF
    Using a theoretical framework based on the next-to-leading order QCD-improved effective Hamiltonian and a factorization Ansatz for the hadronic matrix elements of the four-quark operators, we reassess branching fractions in two-body non-leptonic decays B→PP,PV,VVB \to PP, PV, VV, involving the lowest lying light pseudoscalar (P)(P) and vector (V)(V) mesons in the standard model. Using the sensitivity of the decay rates on the effective number of colors, NcN_c, as a criterion of theoretical predictivity, we classify all the current-current (tree) and penguin transitions in five different classes. The recently measured charmless two-body B→PPB \to PP decays (B+→K+ηâ€Č,B0→K0ηâ€Č,B0→K+π−,B+→π+K0(B^+ \to K^+ \eta^\prime, B^0 \to K^0 \eta^\prime, B^0 \to K^+\pi^-, B^+ \to \pi^+ K^0 and charge conjugates) are dominated by the NcN_c-stable QCD penguins (class-IV transitions) and their estimates are consistent with data. The measured charmless B→PVB \to PV (B+→ωK+, B+→ωh+)(B^+ \to \omega K^+, ~B^+ \to \omega h^+) and B→VVB\to VV transition (B→ϕK∗)(B \to \phi K^*), on the other hand, belong to the penguin (class-V) and tree (class-III) transitions. The class-V penguin transitions are in general more difficult to predict. We propose a number of tests of the factorization framework in terms of the ratios of branching ratios for some selected B→h1h2B \to h_1 h_2 decays involving light hadrons h1h_1 and h2h_2, which depend only moderately on the form factors. We also propose a set of measurements to determine the effective coefficients of the current-current and QCD penguin operators. The potential impact of B→h1h2B \to h_1 h_2 decays on the CKM phenomenology is emphasized by analyzing a number of decay rates in the factorization framework.Comment: 64 pages (LaTex) including 13 figures, requires epsfig.sty; submitted to Phys. Rev.

    Shell evolution approaching the N=20 island of inversion : Structure of 26Na

    Get PDF
    The levels in 26Na with single particle character have been observed for the first time using the d(25Na, pÎł) reaction at 5 MeV/nucleon. The measured excitation energies and the deduced spectroscopic factors are in good overall agreement with (0+1)hω shell model calculations performed in a complete spsdfp basis and incorporating a reduction in the N=20 gap. Notably, the 1p3/2 neutron configuration was found to play an enhanced role in the structure of the low-lying negative parity states in 26Na, compared to the isotone 28Al. Thus, the lowering of the 1p3/2 orbital relative to the 0f7/2 occurring in the neighbouring Z=10 and 12 nuclei - 25,27Ne and 27,29Mg - is seen also to occur at Z=11 and further strengthens the constraints on the modelling of the transition into the island of inversion

    Environmental Design for Dementia Care Towards more Meaningful Experiences through Design

    Get PDF
    Dementia is generally considered to be one of the most pressing societal issues now and in the years to come. Although insights from different disciplines have contributed to a better understanding of dementia and the development of interventions targeting dementia symptoms, there is a lack of integration of insights from these different perspectives for the purposes of design for dementia. The aim of this paper is to show how insights from environmental psychology and advances in technology can inform a user-centred multidisciplinary design approach. To this end, first a brief meta-review of (systematic) reviews from the fields of assistive technology for dementia care and healing environments research is presented, after which gaps and opportunities for a multidisciplinary design approach are identified. To illustrate what such an approach could look like, two exploratory case studies are presented in which technology-enhanced prototypes of an experience handrail (aimed at facilitating wayfinding by providing meaningful sensory experiences) and a virtual nature installation (aimed at providing relaxation and stimulating social engagement) were implemented at a Dutch care centre for people with dementia. Preliminary evaluations indicate that these designs contribute to the wellbeing of people with dementia and confirm the fruitfulness of the design approach presented in this paper. Furthermore, this approach may not only provide a means to optimize existing environments and enhance ease of living, but may also lead to novel solutions to the challenges people with dementia face on a day-to-day basis, and improve their quality of life

    Amyloid and tau pathology associations with personality traits, neuropsychiatric symptoms, and cognitive lifestyle in the preclinical phases of sporadic and autosomal dominant Alzheimer’s disease

    Get PDF
    Background Major prevention trials for Alzheimer’s disease (AD) are now focusing on multidomain lifestyle interventions. However, the exact combination of behavioral factors related to AD pathology remains unclear. In 2 cohorts of cognitively unimpaired individuals at risk of AD, we examined which combinations of personality traits, neuropsychiatric symptoms, and cognitive lifestyle (years of education or lifetime cognitive activity) related to the pathological hallmarks of AD, amyloid-ÎČ, and tau deposits. Methods A total of 115 older adults with a parental or multiple-sibling family history of sporadic AD (PREVENT-AD [PRe-symptomatic EValuation of Experimental or Novel Treatments for AD] cohort) underwent amyloid and tau positron emission tomography and answered several questionnaires related to behavioral attributes. Separately, we studied 117 mutation carriers from the DIAN (Dominant Inherited Alzheimer Network) study group cohort with amyloid positron emission tomography and behavioral data. Using partial least squares analysis, we identified latent variables relating amyloid or tau pathology with combinations of personality traits, neuropsychiatric symptoms, and cognitive lifestyle. Results In PREVENT-AD, lower neuroticism, neuropsychiatric burden, and higher education were associated with less amyloid deposition (p = .014). Lower neuroticism and neuropsychiatric features, along with higher measures of openness and extraversion, were related to less tau deposition (p = .006). In DIAN, lower neuropsychiatric burden and higher education were also associated with less amyloid (p = .005). The combination of these factors accounted for up to 14% of AD pathology. Conclusions In the preclinical phase of both sporadic and autosomal dominant AD, multiple behavioral features were associated with AD pathology. These results may suggest potential pathways by which multidomain interventions might help delay AD onset or progression

    Use of SMS texts for facilitating access to online alcohol interventions: a feasibility study

    Get PDF
    A41 Use of SMS texts for facilitating access to online alcohol interventions: a feasibility study In: Addiction Science & Clinical Practice 2017, 12(Suppl 1): A4

    Search for gravitational waves from Scorpius X-1 in the second Advanced LIGO observing run with an improved hidden Markov model

    Get PDF
    We present results from a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to track spin wandering. This search improves on previous HMM-based searches of LIGO data by using an improved frequency domain matched filter, the J-statistic, and by analyzing data from Advanced LIGO's second observing run. In the frequency range searched, from 60 to 650 Hz, we find no evidence of gravitational radiation. At 194.6 Hz, the most sensitive search frequency, we report an upper limit on gravitational wave strain (at 95% confidence) of h095%=3.47×10-25 when marginalizing over source inclination angle. This is the most sensitive search for Scorpius X-1, to date, that is specifically designed to be robust in the presence of spin wandering. © 2019 American Physical Society
    • 

    corecore