244 research outputs found

    Ex-nihilo II: Examination Syllabi and the Sequencing of Cosmology Education

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    Cosmology education has become an integral part of modern physics courses. Directed by National Curricula, major UK examination boards have developed syllabi that contain explicit statements about the model of the Big Bang and the strong observational evidence that supports it. This work examines the similarities and differences in these specifications, addresses when cosmology could be taught within a physics course, what should be included in this teaching and in what sequence it should be taught at different levels.Comment: 9 pages. Accepted for publication in a special issue of Physics Educatio

    INTERNALISASI KECAKAPAN 4C MELALUI REDUKSI TEKS PUISI DALAM PEMBELAJARAN SASTRA

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    In line with the development of the world paradigm of the advancement of science and technology called the industrial revolution 4.0, education is faced with heavy competition. These challenges require education to be able to produce competent human resources to be able to compete in the era of the industrial revolution 4.0. Mandatory competence in this era includes critical, creative, communicative, and collaborative policies as a designed foundation. In the context of the 2013 curriculum, Indonesian language learning has the potential to internalize these competencies through literary texts. Literary learning is the right tool to create critical, creative, communicative, and collaborative skills. This can be obtained through text analysis or study activities and the production of literary texts. One of the literary works in the 2013 curriculum is poetry text. The poem texts are titled "Kerendahan Hati" by Taufik Ismail, "Jembatan" by Sutardji Calzoum Bachri, and "Bunga dan Tembok" by Wiji Tukul

    Bayesian sequential integration within a preclinical pharmacokinetic and pharmacodynamic modeling framework:Lessons learned

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    The present manuscript aims to discuss the implications of sequential knowledge integration of small preclinical trials in a Bayesian pharmacokinetic and pharmacodynamic (PK-PD) framework. While, at first sight, a Bayesian PK-PD framework seems to be a natural framework to allow for sequential knowledge integration, the scope of this paper is to highlight some often-overlooked challenges while at the same time providing some guidances in the many and overwhelming choices that need to be made. Challenges as well as opportunities will be discussed that are related to the impact of (1) the prior specification, (2) the choice of random effects, (3) the type of sequential integration method. In addition, it will be shown how the success of a sequential integration strategy is highly dependent on a carefully chosen experimental design when small trials are analyzed

    Instrumental variable estimation in semi-parametric additive hazards models

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    Instrumental variable methods allow unbiased estimation in the presence of unmeasured confounders when an appropriate instrumental variable is available. Two-stage least-squares and residual inclusion methods have recently been adapted to additive hazard models for censored survival data. The semi-parametric additive hazard model which can include time-independent and time-dependent covariate effects is particularly suited for the two-stage residual inclusion method, since it allows direct estimation of time-independent covariate effects without restricting the effect of the residual on the hazard. In this article we prove asymptotic normality of two-stage residual inclusion estimators of regression coefficients in a semi-parametric additive hazard model with time-independent and time-dependent covariate effects. We consider the cases of continuous and binary exposure. Estimation of the conditional survival function given observed covariates is discussed and a resampling scheme is proposed to obtain simultaneous confidence bands. The new methods are compared to existing ones in a simulation study and are applied to a real data set. The proposed methods perform favourably especially in cases with exposure-dependent censoring

    Study to evaluate the optimal dose of remifentanil required to ensure apnea during magnetic resonance imaging of the heart under general anesthesia

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    Background: Magnetic resonance (MRI) scanning of the heart is an established part of the investigation of cardiovascular conditions in children. In young children, sedation is likely to be needed, and multiple controlled periods of apnea are often required to allow image acquisition. Suppression of spontaneous ventilation is possible with remifentanil; however, the dose required is uncertain. Aims: To establish the dose of remifentanil, by infusion, required to suppress ventilation sufficiently to allow a 30-s apnea during MRI imaging of the heart. Method: Patients aged 1–6 years were exposed to different doses of remifentanil, and the success in achieving a 30-s apnea was recorded. A dose recommendation was made for each patient, informed by responses of previous patients using an adaptive Bayesian dose-escalation design. Other aspects of anesthesia were standardized. A final estimate of the dose needed to achieve a successful outcome in 80% of patients (ED80) was made using logistic regression. Results: 38 patients were recruited, and apnea achieved in 31 patients. The estimate of the ED80 was 0.184 µg/kg/min (95% CI 0.178–0.190). Post hoc analysis revealed that higher doses were required in younger patients. Conclusion: The ED80 for this indication was 0.184 µg/kg/min (95% CI 0.178–0.190). This is different from optimal dosing identified for other indications and dosing of remifentanil should be specific to the clinical context in which it is used

    Transitions from Telephone Surveys to Self-Administered and Mixed-Mode Surveys: AAPOR Task Force Report

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    Telephone surveys have been a ubiquitous method of collecting survey data, but the environment for telephone surveys is changing. Many surveys are transitioning from telephone to self-administration or combinations of modes for both recruitment and survey administration. Survey organizations are conducting these transitions from telephone to mixed modes with only limited guidance from existing empirical literature and best practices. This article summarizes findings by an AAPOR Task Force on how these transitions have occurred for surveys and research organizations in general. We find that transitions from a telephone to a selfadministered or mixed-mode survey are motivated by a desire to control costs, to maintain or improve data quality, or both. The most common mode to recruit respondents when transitioning is mail, but recent mixedmode studies use only web or mail and web together as survey administration modes. Although early studies found that telephone response rates met or exceeded response rates to the self-administered or mixed modes, after about 2013, response rates to the self-administered or mixed modes tended to exceed those for the telephone mode, largely because of a decline in the telephone mode response rates. Transitioning offers opportunities related to improved frame coverage and geographic targeting, delivery of incentives, visual design of an instrument, and cost savings, but challenges exist related to selecting a respondent within a household, length of a questionnaire, differences across modes in use of computerization to facilitate skip patterns and other questionnaire design features, and lack of an interviewer for respondent motivation and clarification. Other challenges related to surveying youth, conducting surveys in multiple languages, collecting nonsurvey data such as biomeasures or consent to link to administrative data, and estimation with multiple modes are also prominent

    Assessing goodness-of-fit for evaluation of dose-proportionality

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    For the clinical development of a new drug, the determination of dose-proportionality is an essential part of the pharmacokinetic evaluations, which may provide early indications of non-linear pharmacokinetics and may help to identify sub-populations with divergent clearances. Prior to making any conclusions regarding dose-proportionality, the goodness-of-fit of the model must be assessed to evaluate the model performance. We propose the use of simulation-based visual predictive checks to improve the validity of dose-proportionality conclusions for complex designs. We provide an illustrative example and include a table to facilitate review by regulatory authorities

    Costs and staffing resource requirements for adaptive clinical trials: quantitative and qualitative results from the Costing Adaptive Trials project

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    Background Adaptive designs offer great promise in improving the efficiency and patient-benefit of clinical trials. An important barrier to further increased use is a lack of understanding about which additional resources are required to conduct a high-quality adaptive clinical trial, compared to a traditional fixed design. The Costing Adaptive Trials (CAT) project investigated which additional resources may be required to support adaptive trials. Methods We conducted a mock costing exercise amongst seven Clinical Trials Units (CTUs) in the UK. Five scenarios were developed, derived from funded clinical trials, where a non-adaptive version and an adaptive version were described. Each scenario represented a different type of adaptive design. CTU staff were asked to provide the costs and staff time they estimated would be needed to support the trial, categorised into specified areas (e.g. statistics, data management, trial management). This was calculated separately for the non-adaptive and adaptive version of the trial, allowing paired comparisons. Interviews with 10 CTU staff who had completed the costing exercise were conducted by qualitative researchers to explore reasons for similarities and differences. Results Estimated resources associated with conducting an adaptive trial were always (moderately) higher than for the non-adaptive equivalent. The median increase was between 2 and 4% for all scenarios, except for sample size re-estimation which was 26.5% (as the adaptive design could lead to a lengthened study period). The highest increase was for statistical staff, with lower increases for data management and trial management staff. The percentage increase in resources varied across different CTUs. The interviews identified possible explanations for differences, including (1) experience in adaptive trials, (2) the complexity of the non-adaptive and adaptive design, and (3) the extent of non-trial specific core infrastructure funding the CTU had. Conclusions This work sheds light on additional resources required to adequately support a high-quality adaptive trial. The percentage increase in costs for supporting an adaptive trial was generally modest and should not be a barrier to adaptive designs being cost-effective to use in practice. Informed by the results of this research, guidance for investigators and funders will be developed on appropriately resourcing adaptive trials
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