895 research outputs found

    The impact of Roman rule on the urban system of Sicily

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    The Unification of the Mediterranean World (400 BC - 400 AD

    Resveratrol:A booster of mitochondria

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    Twee antieke kredietcrises

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    Bevolkingontwikkeling en armoede in laat-Republikeins Italië

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    Economie en maatschappij van de Grieks-Romeinse Sta

    Cost-effectiveness of shifting breast cancer surveillance from a hospital setting to a community-based national screening programme setting

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    Background: In the Netherlands, breast cancer surveillance after breast conserving surgery (BCS) takes place in a hospital setting for at least five years to detect possible recurrences in early stage. As breast cancer incidence rises and mortality decreases, surveillance expenses increase. This study explores the effectiveness and cost-effectiveness of BCS surveillance as delivered in a hospital setting versus providing BCS surveillance as part of the community-based National Breast Cancer Screening Program (NBCSP). We hypothesise that the NBCSP-based strategy leads to lower costs and a lower proportion of true test results (TTR) compared to the hospital-based strategy and determine to what extent potential lower effectiveness may be balanced with expected cost savings. Materials and Methods: Both strategies are compared on effectiveness and cost-effectiveness in a decision tree from a healthcare perspective over a 5-year time horizon. Women aged 50–75 without distant metastases that underwent BCS in the years 2003–2006 with complete 5 year follow-up were selected from the Netherlands Cancer Registry (n = 14,093). Key input variables were mammography sensitivity and specificity, risk of loco regional recurrence (LRR), and direct healthcare costs. The primary outcome measure was the overall predictive value (measured in true test results). Secondary effectiveness measures were the positive predictive value (PPV) (LRRs detected or true positive test results) and the negative predictive value (NPV) (true negative test results) detected within five years post-treatment. Results are presented for low and high risk patients separately and expressed in incremental cost-effectiveness ratios (ICERs). Results: For low risk patients (with grade 1 tumours, no node involvement, and hormonal treatment), the PPV and NPV for the NBCSP strategy were 3.31% and 99.88%, and 2.74% and 99.95% for the hospital strategy respectively. For high risk patients (grade 3 tumours, over three nodes involved, without hormonal treatment), the PPV and NPV for the NBCSP strategy were 64.1% and 98.9%; and 51.0% and 99.7% for the hospital strategy respectively. For low risk patients the NBCSP saves €202 per patient leading to an ICER of €109/accurate test result. For high risk patients the cost savings are €72 per patient, leading to an ICER of €43/accurate test result. Conclusion: Although the NBCSP-based strategy is cheaper, it cannot replace the hospital-based strategy, since it leads to only half of the accurate test results compared to hospital-based strategy. This contradicts the goal of early detection of LRRs and improving outcomes

    Practical and conceptual issues in the use of agent-based modelling for disaster management

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    Application of agent-based modelling technology (ABM) to disaster management has to date been limited in nature. Existing research has concentrated on extending the model structures and agent architectures of complex algorithms to test robustness and extensibility of this simulation approach. Less attention has been brought to bear on testing the current state-of-the-art in ABM for modelling real-life systems. This thesis aims to take first steps in remedying this gap. It focuses on identifying the practical and conceptual issues which preclude wider utilisation of ABM in disaster management. It identifies that insufficient attention is put on incorporating real-life information and domain knowledge into model definitions. This research first proposes a methodology by which some of these issues may be overcome, and consequently tests and evaluates it through implementation of InSiM (Incident Simulation Model), which depicts reaction of pedestrians to a CBRN (chemical, biological, radiological or nuclear) explosion in a city centre. A number of steps are conducted to obtain real-life information related to human response to CBRN incidents. This information is then used for design and parameterisation of InSiM which is implemented in three configurations. In order to identify the effects use of real-life data have on the simulation results each configuration incorporates the information at different level of complexity. The effects are assessed by comparison of the generated dispersion patterns of agents along the city centre. However, use of conventional statistical goodness-of-fit tests for assessing the degree of the difference was challenged by inhomogeneous nature of the data. Hence, alternative approaches are also adopted so that results can be qualitatively assessed. Nevertheless, the evaluation reveals significant differences at global and local level. This research highlights that incorporation of real-life information and domain knowledge into ABM is not without problems. Each time a problem was addressed, additional issues began to emerge. Most of these challenges were related to generalisation of the complex real-life systems that the model represents. Therefore, further investigations are needed at every methodological step before ABM can fully realise its potential to support disaster management

    2D-based indoor mobile laser scanning for construction digital mapping application

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    A common issue which occurs often in construction projects is how to determine the discrepancies between as-built or existing constructions and initial design. Physical manual measurement usually brings many of problems such as long measuring time, high labor consumption, and measurement error accumulation and in some cases lower accuracy. Therefore, more advanced technologies such as laser scanning and total station, which are used in geospatial mapping and surveying have been adopted in order to provide much more reliable and accurate measurements. However, technical and financial issues still constrain the widespread applications of well-known 3-dimensional (3D) terrestrial and aerial laser scanning, such as high equipment cost, complex pre-preparation, inconvenience of use and spatial limitation. This paper aims to introduce an innovative laser scanning method for indoor construction mapping. This method integrates an IMU-GPS positioning approach with a more convenient, more time saving and lower costed 2-dimensional (2D) laser scanner to realize indoor mobile 3D mapping for construction model creation, which can be integrated with Building Information Modelling (BIM) design in order to realize the applications, such as quality control of as-built construction or indoor mapping of existing building. Although compared with traditional 3D laser scanning, its accuracy and reliability cannot reach such a high level currently, experimental results still indicate feasibility, reliability and potential capability of this indoor mobile laser scanning method. It is hoped that this method will be further improved to substitute the stationary 3D laser scanning for narrow and limited construction spatial mapping in the near future
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