1,574 research outputs found

    Measurement of the Drell{Yan triple-differential cross-section in pp collisions at ps = 8 TeV with the ATLAS detector

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    PhDThis thesis presents the measurement and results of the Z= ! + �� Drell{Yan tripledi erential cross-section, using 20:24 fb��1of ATLAS data recorded in 2012 at a centre-of-mass energy of ps = 8TeV. The triple-differential cross-section is measured as a function of dimuon invariant mass, m , dimuon rapidity, y , and lepton decay angle in the Collins-Soper frame, cos . These dimensions provide sensitivity to the parton composition of the proton through the parton density functions, PDFs, and the weak e ective mixing angle, sin2 e : W , via the forward-backward asymmetry, AFB. The measurement is performed on and around the Z-boson's invariant mass peak, 46 20 GeV, and muon pseudo-rapidity j j 2:4. The results are unfolded from the detector level to the Born, bare and dressed levels, where a precision of < 0:6% is reported in the central bins. The data is combined with an electron channel measurement resulting in a combined result with reduced total uncertainty. The combined result is shown to constrain PDF uncertainties and achieve the most constrained sin2 e : W uncertainty yet reported at the LHC

    A deconvolution map-making method for experiments with circular scanning strategies

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    Aims. To investigate the performance of a deconvolution map-making algorithm for an experiment with a circular scanning strategy, specifically in this case for the analysis of Planck data, and to quantify the effects of making maps using simplified approximations to the true beams. Methods. We present an implementation of a map-making algorithm which allows the combined treatment of temperature and polarisation data, and removal of instrumental effects, such as detector time constants and finite sampling intervals, as well as the deconvolution of arbitrarily complex beams from the maps. This method may be applied to any experiment with a circular scanning-strategy. Results. Low-resolution experiments were used to demonstrate the ability of this method to remove the effects of arbitrary beams from the maps and to demonstrate the effects on the maps of ignoring beam asymmetries. Additionally, results are presented of an analysis of a realistic full-scale simulated data-set for the Planck LFI 30 GHz channel. Conclusions. Our method successfully removes the effects of the beams from the maps, and although it is computationally expensive, the analysis of the Planck LFI data should be feasible with this approach.Comment: 14 pages, 14 figures, accepte

    Large-Scale Polarized Foreground Component Separation for Planck

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    We use Bayesian component estimation methods to examine the prospects for large-scale polarized map and cosmological parameter estimation with simulated Planck data assuming simplified white noise properties. The sky signal is parametrized as the sum of the CMB, synchrotron emission, and thermal dust emission. The synchrotron and dust components are modelled as power-laws, with a spatially varying spectral index for synchrotron and a uniform index for dust. Using the Gibbs sampling technique, we estimate the linear polarisation Q and U posterior amplitudes of the CMB, synchrotron and dust maps as well as the two spectral indices in ~4 degree pixels. We use the recovered CMB map and its covariance in an exact pixel likelihood algorithm to estimate the optical depth to reionization tau, the tensor-to-scalar ratio r, and to construct conditional likelihood slices for the EE and BB spectra. Given our foreground model, we find sigma(tau)~0.004 for tau=0.1, sigma(r)~0.03 for a model with r=0.1, and a 95% upper limit of r<0.02 for r=0.0.Comment: 15 pages, 12 figures, submitted to MNRA

    Enacting person-centredness in integrated care: A qualitative study of practice and perspectives within Multidisciplinary Groups in the care of older people

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    BACKGROUND: Person-centredness is important in delivering care for long-term conditions. New models of care aim to co-ordinate care through integration of health and social care which require new ways of working, often remotely from the patient. OBJECTIVE: To describe how person-centred care is enacted within multidisciplinary groups (MDGs) created as part of a new service, integrating health and social care for older people. METHODS: We followed the implementation of eight neighbourhood MDGs, observing and interviewing staff from three MDGs at different phases of programme implementation using semi-structured topic guides. RESULTS: Thirty-four MDG meetings were observed and 32 staff interviewed. Three core themes were identified which impacted on enactment of person-centred care: the structural context of MDGs enabling person-centred care; interaction of staff and knowledge sharing during the MDG meetings; and direct staff involvement of the person outside the MDG discussion. CONCLUSIONS: This study provides new insights into attempts to enact person-centred care within a new model of service delivery. Teams did what they could to enact person-centred care in the absence of the "real" patient within MDG meetings. They were successful in delivering and co-ordinating some aspects of care (eg prompting medication reviews, referring to social worker, health improvement and arranging further multidisciplinary team meetings for complex cases). This "absence of patients" and time pressures within the MDGs led to reliance on the "virtual" record, enhanced by additional "soft" knowledge provided by staff, rather than ensuring the patient's voice was included

    Bioinformatic characterisation of the effector repertoire of the strawberry pathogen Phytophthora cactorum

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    The oomycete pathogen Phytophthora cactorum causes crown rot, a major disease of cultivated strawberry. We report the draft genome of P. cactorum isolate 10300, isolated from symptomatic Fragaria x ananassa tissue. Our analysis revealed that there are a large number of genes encoding putative secreted effectors in the genome, including nearly 200 RxLR domain containing effectors, 77 Crinklers (CRN) grouped into 38 families, and numerous apoplastic effectors, such as phytotoxins (PcF proteins) and necrosis inducing proteins. As in other Phytophthora species, the genomic environment of many RxLR and CRN genes differed from core eukaryotic genes, a hallmark of the two-speed genome. We found genes homologous to known Phytophthora infestans avirulence genes including Avr1, Avr3b, Avr4, Avrblb1 and AvrSmira2 indicating effector sequence conservation between Phytophthora species of clade 1a and clade 1c. The reported P. cactorum genome sequence and associated annotations represent a comprehensive resource for avirulence gene discovery in other Phytophthora species from clade 1 and, will facilitate effector informed breeding strategies in other crops

    A Study into the Effect of the Presence of Moisture at the Wheel/Rail Interface during Dew and Damp Conditions

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    Incidents involving low levels of adhesion between the wheel and rail are a recurrent issue in the rail industry. The problem has been mitigated using friction modifiers and traction enhancers, but a significant number of incidents still occur throughout the year. The following work looks at the environmental conditions that surround periods of low adhesion in order to provide an insight into why low adhesion events occur. Network Rail Autumn data, which provided details on the time and location of low adhesion incidents, was compared against weather data on a national and then local scale. Low adhesion incidents have often been attributed to contamination on the rail, such as organic leaf matter, but other incidents occur when no contamination is visible. The time, date and location of incidents were linked to local weather data to establish any specific weather conditions that could lead to these events. The effects of precipitation, temperature and humidity on the rail were analysed in order to further the understanding of low adhesion in the wheel-rail contact, which will lead to better methods of mitigating this problem

    Calcium supplements and risk of CVD: A meta-analysis of randomized trials

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    Background: Vitamin D supplements may only be beneficial for the prevention of osteoporotic fractures when administered with calcium and in individuals with low blood levels of 25(OH)D, but possible hazards of calcium supplements on CVD cannot be excluded. Objectives: We conducted a meta-analysis of all placebo-controlled randomized trials assessing the effects of calcium supplements alone or with vitamin D on CHD, stroke, and all-cause mortality. Methods: A meta-analysis of 11 trials included 7 comparisons of calcium alone compared with control (n = 8634) and 6 comparisons of calcium plus vitamin D compared with control (n = 46,804). Aggregated study-level data were obtained from individual trials and combined using a fixed-effects meta-analysis. The main outcomes included MI, CHD death, any CHD, stroke, and all-cause mortality. Results: Among trials of calcium alone (mean daily dose 1 g), calcium was not significantly associated with any excess risk of MI (RR, 1.15; 95% CI: 0.88, 1.51; n = 219 events), CHD death (RR, 1.24; 95% CI: 0.89, 1.73; n = 142), any CHD (RR, 1.01; 95% CI: 0.75, 1.37; n = 177), or stroke (RR, 1.15; 95% CI, 0.90, 1.46, n = 275). Among 6 trials of combined treatment, supplementation with calcium plus vitamin D was not significantly associated with any excess risk of MI (RR, 1.09; 95% CI: 0.95, 1.25; n = 854), CHD death (RR, 1.04; 95% CI: 0.85, 1.27; n = 391), any CHD (RR, 1.05; 95% CI: 0.93, 1.19; n = 1061), or stroke (RR, 1.02; 95% CI: 0.89, 1.17; n = 885). Likewise, calcium alone, or with vitamin D had no significant associations with all-cause mortality. Conclusions: This meta-analysis demonstrated that calcium supplements were not associated with any significant hazard for CHD, stroke, or all-cause mortality and excluded excess risks above 0.3%–0.5% per year for CHD or stroke. Further trials of calcium and vitamin D are required in individuals with low blood levels of 25(OH)D for the prevention of fracture and other disease outcomes
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