26,219 research outputs found

    Towards a theory of heuristic and optimal planning for sequential information search

    No full text

    Capturing complexity in clinician case-mix: classification system development using GP and physician associate data.

    Get PDF
    Background: There are limited case-mix classification systems for primary care settings which are applicable when considering the optimal clinical skill mix to provide services. Aim: To develop a case-mix classification system (CMCS) and test its impact on analyses of patient outcomes by clinician type, using example data from physician associates' (PAs) and GPs' consultations with same-day appointment patients. Design & setting: Secondary analysis of controlled observational data from six general practices employing PAs and six matched practices not employing PAs in England. Method: Routinely-collected patient consultation records (PA n = 932, GP n = 1154) were used to design the CMCS (combining problem codes, disease register data, and free text); to describe the case-mix; and to assess impact of statistical adjustment for the CMCS on comparison of outcomes of consultations with PAs and with GPs. Results: A CMCS was developed by extending a system that only classified 18.6% (213/1147) of the presenting problems in this study's data. The CMCS differentiated the presenting patient's level of need or complexity as: acute, chronic, minor problem or symptom, prevention, or process of care, applied hierarchically. Combination of patient and consultation-level measures resulted in a higher classification of acuity and complexity for 639 (30.6%) of patient cases in this sample than if using consultation level alone. The CMCS was a key adjustment in modelling the study's main outcome measure, that is rate of repeat consultation. Conclusion: This CMCS assisted in classifying the differences in case-mix between professions, thereby allowing fairer assessment of the potential for role substitution and task shifting in primary care, but it requires further validation

    African Trade Policy in the 1990s: Political Economy or Technocratic Reforms?

    Get PDF
    The majority of African countries implemented import liberalisation in the 1990s. This paper explores factors that may explain the pattern of protection and of tariff reform. We consider political economy explanations, motivated specifically by the Grossman and Helpman (1994) model of protection in response to industry lobbies, and the possibility that reforms are technocratic. Using industry-level data for a sample of six African countries, we find limited evidence that political economy factors have influenced the pattern of tariffs or tariff reductions since the early 1990s. One result does appear frequently: relative sector size (measured by the number of employees or establishments) appears to be associated with the relative level of protection. We then explore various descriptive statistics for tariff changes in seven African countries. The analysis suggests that the pattern of tariff reductions was essentially technocratic in structure - across the board reduction in average tariffs and in the dispersion of rates, with larger proportional reductions for higher tariffs – consistent with policy reforms being guided by the World Bank. While political economy factors may have influenced the initial pattern of protection, the technocratic reforms since the early 1990s have diluted political economy influences on average and relative protection.Pattern of Protection, Tariff Reform, Political Economy, Africa

    Antinucleus Production at RHIC

    Full text link
    Light antinuclei may be formed in relativistic heavy ion collisions via final state coalescence of antinucleons. The yields of antinuclei are sensitive to primordial antinucleon production, the volume of the system at kinetic freeze-out, and space-momentum correlations among antinucleons at freeze-out. We report here preliminary STAR results on antideuteron and antihelion production in 130A GeV Au+Au collisions. These results are examined in a coalescence framework to elucidate the space-time structure of the antinucleon source.Comment: 4 pages, 3 figures, talk given at Quark Matter 200

    Resonance Studies at STAR

    Full text link
    We report on the observed signals of K⋆0(892)→πK{K^{\star0}(892)}\to\pi K and ϕ(1020)→K+K−\phi(1020)\to K^{+}K^{-} using the mixed-event method with powerful statistics from the large acceptance and highly efficient STAR TPC. Preliminary results from the first observation of such states from the year-one STAR data in sNN=130\sqrt{s_{NN}}=130 GeV Au-Au collisions are presented. The K⋆0/h−K^{\star0}/h^{-} ratios with an assumed K⋆0K^{\star0} pTp_{T} inverse slope of 300MeV are compatible with that from pp at ISR. For 14% central Au+Au collisions, we observe K⋆0/h−=0.060±0.007(stat)K^{\star0}/h^{-}=0.060\pm0.007(stat) and K⋆0ˉ/h−=0.058±0.007(stat)\bar{K^{\star0}}/h^{-}=0.058\pm0.007(stat). We show that Λˉ/Λ=0.77±0.07(stat)\bar{\Lambda}/\Lambda=0.77\pm0.07(stat) from this method is consistent with the measurement via decay topology.Comment: 4 pages, 4 figures, Quark Matter 2001, contributed talk; typos of K*/h- numbers in abstract fixe

    Spin physics with STAR

    Get PDF
    The STAR collaboration aims to study polarized proton-proton collisions at RHIC. The emphasis of the spin run this year is on transverse single spin asymmetries. Beyond 2001, we aim to determine directly and precisely the gluon polarization, as well as the polarizations of the u, uˉ\bar{u}, d and dˉ\bar{d} quarks in the proton by measuring in addition longitudinal and double spin asymmetries. Furthermore, we aim to measure for the first time the quark transversity distributions. These measurements will improve substantially the knowledge and understanding of the spin structure of the nucleon.Comment: 9 pages, 3 figures. Talk presented at The 3rd Circum-Pan-Pacific Symposium on "High Energy Spin Physics" October 8-13 2001, Beijing, Chin

    Elliptic flow in Au+Au collisions at sNN\sqrt{s_{_{NN}}} = 130 GeV

    Full text link
    We report the elliptic flow of charged and identified particles at mid-rapidity in Au+Au collisions at sNN=130\sqrt{s_{_{NN}}}=130 GeV using the STAR TPC at RHIC. The integrated elliptic flow signal, v2v_2, for charged particles reaches values of about 0.06, indicating a higher degree of thermalization than at lower energies. The differential elliptic flow signal, v2v_2(ptp_t) up to 1.5 GeV/cc, shows a behavior expected from hydrodynamic model calculations. Above 1.5 GeV/cc, the data deviate from the hydro predictions; however the v2v_2(ptp_t) is still large, suggesting finite asymmetry for the products of hard scattering. For the identified particles, elliptic flow as a function of ptp_t and centrality differ significantly for particles of different masses. This dependence can be accounted for in hydrodynamic models, indicating that the system created shows a behavior consistent with collective hydrodynamical flow.Comment: 6 pages, 8 figures, Quark Matter 200

    Azimuthal correlations of forward di-hadrons in d+Au collisions at RHIC in the Color Glass Condensate

    Full text link
    We present a good description of recent experimental data on forward di-hadron azimuthal correlations measured in deuteron-gold collisions at RHIC, where monojet production has been observed. Our approach is based on the Color Glass Condensate effective theory for the small-x degrees of freedom of the nuclear wave function, including the use of non-linear evolution equations with running QCD coupling. Our analysis provides further evidence for the presence of saturation effects in RHIC data.Comment: 4 pages, 2 figures, version to appear in PR
    • …
    corecore