159 research outputs found

    Development of an airline revenue capability model for aircraft design

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    Typically value based approaches to the design of civil and commercial aircraft, be they net present value, surplus value, or any other utility based approach focus solely on the difference in cost between the alternatives, neglecting changes in revenue which might occur between the two concepts. Alternatively, if they do have a revenue focus, it is based upon simple relationships between payload capacity and revenue, assuming a either a fixed protfimargin or fixed yield. This approach works well when comparing two similar or closely related concepts, but falls apart when investigating more radically di erent systems, e.g. a cruise eficient short take-o and landing concept. By using a value based approach it is relatively simple to structure a decision model to incorporate changing revenue capability. However, the ability to investigate differences in design is very much dependent upon the revenue model and assumptions that are made. If the revenue elasticity is the same forthe two concepts then there is no benefi t in using a variable revenue approach. However, in the cases where the elasticity is different, the revenue approach offers the potential to more properly investigate some fundamentally different alternative concepts. © 2010 by Peter Sutcliffe & Peter Hollingsworth. Published by the American Institute of Aeronautics and Astronautics, Inc

    Germline heterozygous DDX41 variants in a subset of familial myelodysplasia and acute myeloid leukemia

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    The Brazilian National Council for Scientific and Technological Development), Bloodwise, Children with Cancer and MRC (Medical Research Council, UK)

    Extrapolation for Time-Series and Cross-Sectional Data

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    Extrapolation methods are reliable, objective, inexpensive, quick, and easily automated. As a result, they are widely used, especially for inventory and production forecasts, for operational planning for up to two years ahead, and for long-term forecasts in some situations, such as population forecasting. This paper provides principles for selecting and preparing data, making seasonal adjustments, extrapolating, assessing uncertainty, and identifying when to use extrapolation. The principles are based on received wisdom (i.e., experts’ commonly held opinions) and on empirical studies. Some of the more important principles are:• In selecting and preparing data, use all relevant data and adjust the data for important events that occurred in the past.• Make seasonal adjustments only when seasonal effects are expected and only if there is good evidence by which to measure them.• In extrapolating, use simple functional forms. Weight the most recent data heavily if there are small measurement errors, stable series, and short forecast horizons. Domain knowledge and forecasting expertise can help to select effective extrapolation procedures. When there is uncertainty, be conservative in forecasting trends. Update extrapolation models as new data are received.• To assess uncertainty, make empirical estimates to establish prediction intervals.• Use pure extrapolation when many forecasts are required, little is known about the situation, the situation is stable, and expert forecasts might be biased

    A study protocol of a randomised controlled trial incorporating a health economic analysis to investigate if additional allied health services for rehabilitation reduce length of stay without compromising patient outcomes

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    Background Reducing patient length of stay is a high priority for health service providers. Preliminary information suggests additional Saturday rehabilitation services could reduce the time a patient stays in hospital by three days. This large trial will examine if providing additional physiotherapy and occupational therapy services on a Saturday reduces health care costs, and improves the health of hospital inpatients receiving rehabilitation compared to the usual Monday to Friday service. We will also investigate the cost effectiveness and patient outcomes of such a service. Methods/Design A randomised controlled trial will evaluate the effect of providing additional physiotherapy and occupational therapy for rehabilitation. Seven hundred and twelve patients receiving inpatient rehabilitation at two metropolitan sites will be randomly allocated to the intervention group or control group. The control group will receive usual care physiotherapy and occupational therapy from Monday to Friday while the intervention group will receive the same amount of rehabilitation as the control group Monday to Friday plus a full physiotherapy and occupational therapy service on Saturday. The primary outcomes will be patient length of stay, quality of life (EuroQol questionnaire), the Functional Independence Measure (FIM), and health utilization and cost data. Secondary outcomes will assess clinical outcomes relevant to the goals of therapy: the 10 metre walk test, the timed up and go test, the Personal Care Participation Assessment and Resource Tool (PC PART), and the modified motor assessment scale. Blinded assessors will assess outcomes at admission and discharge, and follow up data on quality of life, function and health care costs will be collected at 6 and 12 months after discharge. Between group differences will be analysed with analysis of covariance using baseline measures as the covariate. A health economic analysis will be carried out alongside the randomised controlled trial. Discussion This paper outlines the study protocol for the first fully powered randomised controlled trial incorporating a health economic analysis to establish if additional Saturday allied health services for rehabilitation inpatients reduces length of stay without compromising discharge outcomes. If successful, this trial will have substantial health benefits for the patients and for organizations delivering rehabilitation services

    Factors influencing scar formation following Bacille Calmette-Guérin (BCG) vaccination

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    The prevalence of scar formation following Bacille Calmette-Guérin (BCG) vaccination varies globally. The beneficial off-target effects of BCG are proposed to be stronger amongst children who develop a BCG scar. Within an international randomised trial ('BCG vaccination to reduce the impact of coronavirus disease 2019 (COVID-19) in healthcare workers'; BRACE Trial), this nested prospective cohort study assessed the prevalence of and factors influencing scar formation, as well as participant perception of BCG scarring 12 months following vaccination . Amongst 3071 BCG-recipients, 2341 (76%) developed a BCG scar. Scar prevalence was lowest in Spain and highest in UK. Absence of post-injection wheal (OR 0.4, 95%CI 0.2-0.9), BCG revaccination (OR 1.7, 95%CI 1.3-2.0), female sex (OR 2.0, 95%CI 1.7-2.4), older age (OR 0.4, 95%CI 0.4-0.5) and study country (Brazil OR 1.6, 95%CI 1.3-2.0) influenced BCG scar prevalence. Of the 2341 participants with a BCG scar, 1806 (77%) did not mind having the scar. Participants more likely to not mind were those in Brazil, males and those with a prior BCG vaccination history. The majority (96%) did not regret having the vaccine. Both vaccination-related (amenable to optimisation) and individual-related factors affected BCG scar prevalence 12 months following BCG vaccination of adults, with implications for maximising the effectiveness of BCG vaccination.Paola Villanueva, Nigel W. Crawford, Mariana Garcia Croda, Simone Collopy, Bruno Araújo Jardim, Tyane de Almeida Pinto Jardim, Laurens Manning, Michaela Lucas, Helen Marshall, Cristina Prat-Aymerich, Alice Sawka, Ketaki Sharma, Darren Troeman, Ushma Wadia, Adilia Warris, Nicholas Wood, Nicole L. Messina, Nigel Curtis, Laure F. Pitte
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