2,033 research outputs found

    Item Information in the Rasch Model

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    Fisher's information measure for the item difficulty parameter in the Rasch model and its marginal and conditional formulations are investigated. It is shown that expected item information in the unconditional model equals information in the marginal model, provided the assumption of sampling examinees from an ability distribution is made. For the logistic ability distribution considered in this paper, item information in the two models can be expressed in a closed form. Also, it is shown that for a random examinee expected item information in the conditional model is always less than that in the other two models, albeit the difference quickly decreases with an increase in test length. If the distribution of the item difficulties in the test deviates more and more from the ability distribution, item information in all three models takes smaller and smaller values. Results from a simulation study of tests with 5 and 20 items demonstrate these features numerically. Six tables present the results of the simulation study, and one graph illustrates item information in the marginal model

    HUMeral Shaft Fractures: MEasuring Recovery after Operative versus Non-operative Treatment (HUMMER): A multicenter comparative observational study

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    Background: Fractures of the humeral shaft are associated with a profound temporary (and in the elderly sometimes even permanent) impairment of independence and quality of life. These fractures can be treated operatively or non-operatively, but the optimal tailored treatment is an unresolved problem. As no high-quality comparative randomized or observational studies are available, a recent Cochrane review concluded there is no evidence of sufficient scientific quality available to inform the decision to operate or not. Since randomized controlled trials for this injury have shown feasibility issues, this study is designed to provide the best achievable evidence to answer this unresolved problem. The primary aim of this study is to evaluate functional recovery after operative versus non-operative treatment in adult patients who sustained a humeral shaft fracture. Secondary aims include the effect of treatment on pain, complications, generic health-related quality of life, time to resumption of activities of daily living and work, and cost-effectiveness. The main hypothesis is that operative treatment will result in faster recovery. Methods/design. The design of the study will be a multicenter prospective observational study of 400 patients who have sustained a humeral shaft fracture, AO type 12A or 12B. Treatment decision (i.e., operative or non-operative) will be left to the discretion of the treating surgeon. Critical elements of treatment will be registered and outcome will be monitored at regular intervals over the subsequent 12 months. The primary outcome measure is the Disabilities of the Arm, Shoulder, and Hand score. Secondary outcome measures are the Constant score, pain level at both sides, range of motion of the elbow and shoulder joint at both sides, radiographic healing, rate of complications and (secondary) interventions, health-related quality of life (Short-Form 36 and EuroQol-5D), time to resumption of ADL/work, and cost-effectiveness. Data will be analyzed using univariate and multivariable analyses (including mixed effects regression analysis). The cost-effectiveness analysis will be performed from a societal perspective. Discussion. Successful completion of this trial will provide evidence on the effectiveness of operative versus non-operative treatment of patients with a humeral shaft fracture. Trial registration. The trial is registered at the Netherlands Trial Register (NTR3617)

    Implementation and effectiveness of teleneonatology for neonatal intensive care units:a protocol for a hybrid type III implementation pilot

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    Background Telemedicine in neonatal care (TeleNeonatology) has the potential to improve neonatal outcomes, address capacity challenges and influence the emotional burden on parents. TeleNeonatology allows for real-time audiovisual communication between healthcare providers at different neonatal intensive care units (NICUs). Despite the high potential for multiple neonatal use-cases, TeleNeonatology is primarily being used for neonatal resuscitation and has yet to be widely implemented in Europe. Our study aims to evaluate both implementation strategies and effectiveness of TeleNeonatology in a pilot study in The Netherlands. Methods A pre-post implementation study with hybrid type III design will be conducted from 1 January 2023 to 31 December 2024. The year 2023 will serve as a baseline period pre-implementation. From 1 January 2024, a TeleNeonatology device will be integrated within all communication between the NICU-level IV of the Erasmus MC hospital and the NICU-level II at Amphia Hospital. Outcomes of the implementation of the TeleNeo programme will be evaluated using a mixed-methods approach evaluating implementation outcomes, service outcomes and client outcomes. Feasibility, the primary implementation outcome, will be evaluated via a validated questionnaire for parents and personnel. Secondary implementation outcomes will be barriers and facilitators of implementation, based on semi-structured interviews and focus groups. A cost minimisation analysis, using decision trees, will be evaluated as service outcomes. Client outcomes will be assessed via parent-reported transfer experience questionnaires and interviews and the clinical outcomes NICU-level III transfer rate and length of stay. Ethics and dissemination This study was reviewed by the Medical Ethical Committee of the Erasmus Medical Centre, who confirmed that the rules laid down in the Medical Research Involving Human Subjects Act do not apply (identification number: MEC-2023-0561). Results will be published in peer-reviewed journals in two separate scientific articles: the primary evaluation and the cost evaluation.</p

    Search for the production of dark matter in association with top-quark pairs in the single-lepton final state in proton-proton collisions at √s=8 TeV

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    Peer reviewe

    Search for Pair Production of Third-Generation Leptoquarks and Top Squarks in pp Collisions at √s=7  TeV

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    Results are presented from a search for the pair production of third-generation scalar and vector leptoquarks, as well as for top squarks in R-parity-violating supersymmetric models. In either scenario, the new, heavy particle decays into a τ lepton and a b quark. The search is based on a data sample of pp collisions at √s=7  TeV, which is collected by the CMS detector at the LHC and corresponds to an integrated luminosity of 4.8  fb[superscript -1]. The number of observed events is found to be in agreement with the standard model prediction, and exclusion limits on mass parameters are obtained at the 95% confidence level. Vector leptoquarks with masses below 760 GeV are excluded and, if the branching fraction of the scalar leptoquark decay to a τ lepton and a b quark is assumed to be unity, third-generation scalar leptoquarks with masses below 525 GeV are ruled out. Top squarks with masses below 453 GeV are excluded for a typical benchmark scenario, and limits on the coupling between the top squark, τ lepton, and b quark, λ333′ are obtained. These results are the most stringent for these scenarios to date

    Search for new physics in the multijet and missing transverse momentum final state in proton-proton collisions at √s=8 Tev

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    Measurement of the sum ofWW and WZ production with W+dijet events in pp collisions at √ s = 7 TeV

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    A measurement of the inclusive WW+WZ diboson production cross section in proton–proton collisions is reported, based on events containing a leptonically decaying √W boson and exactly two jets. The data sample, collected at s = 7 TeV with the CMS detector at the LHC, corresponds to an integrated luminosity of 5.0 fb−1. The measured value of the sum of the inclusive WW and WZ cross sections is σ(pp → WW + WZ) = 68.9 ± 8.7 (stat.) ± 9.7 (syst.) ± 1.5 (lum.) pb, consistent with the standard model prediction of 65.6±2.2 pb. This is the first measurement of WW+WZ production in pp collisions using this signature. No evidence for anomalous triple gauge couplings is found and upper limits are set on their magnitudes

    Measurement of Higgs boson production and properties in the WW decay channel with leptonic final states

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    Search for vector-like T quarks decaying to top quarks and Higgs bosons in the all-hadronic channel using jet substructure

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