244 research outputs found
Noise emission corrections at intersections based on microscopic traffic simulation
One of the goals of the European IMAGINE project, is to formulate strategies to improve traffic modelling for application in noise mapping. It is well known that the specific deceleration and acceleration dynamics of traffic at junctions can influence local noise emission. However, macroscopic traffic models do not always model intersections, and if they do, only the influence of intersections on travel time is incorporated. In these cases, it would be useful to know what increase or decrease in noise production can be expected at or near intersections. A correction factor for road crossings has been suggested in several national noise emission standards. The question is open whether such a correction factor should be included in future harmonized methods. In this paper, a case study is presented, consisting of a large set of microscopic traffic simulations and associated noise emission calculations, which provides some insight into the specific dynamics of the noise emission near different types of intersections. A spatial approach is used, in which inbound and outbound lanes are divided into deceleration, queuing and acceleration zones. Results from regression analysis on the numerical simulations indicate that meaningful relations between noise corrections and traffic flow parameters such as traffic intensity and composition can be deduced
Modelling Eco-Driving Support System for Microscopic Traffic Simulation
Microscopic traffic simulation is an ideal tool for investigating the network level impacts of eco-driving in different networks and traffic conditions, under varying penetration rates and driver compliance rates. The reliability of the traffic simulation results however rely on the accurate representation of the simulation of the driver support system and the response of the driver to the eco-driving advice, as well as on a realistic modelling and calibration of the driver’s behaviour. The state-of-the-art microscopic traffic simulation models however exclude detailed modelling of the driver response to eco-driver support systems. This paper fills in this research gap by presenting a framework for extending state-of-the-art traffic simulation models with sub models for drivers’ compliance to advice from an advisory eco-driving support systems. The developed simulation framework includes among others a model of driver’s compliance with the advice given by the system, a gear shifting model and a simplified model for estimating vehicles maximum possible acceleration. Data from field operational tests with a full advisory eco-driving system developed within the ecoDriver project was used to calibrate the developed compliance models. A set of verification simulations used to illustrate the effect of the combination of the ecoDriver system and drivers’ compliance to the advices are also presented
The stepped wedge trial design: a systematic review
BACKGROUND: Stepped wedge randomised trial designs involve sequential roll-out of an intervention to participants (individuals or clusters) over a number of time periods. By the end of the study, all participants will have received the intervention, although the order in which participants receive the intervention is determined at random. The design is particularly relevant where it is predicted that the intervention will do more good than harm (making a parallel design, in which certain participants do not receive the intervention unethical) and/or where, for logistical, practical or financial reasons, it is impossible to deliver the intervention simultaneously to all participants. Stepped wedge designs offer a number of opportunities for data analysis, particularly for modelling the effect of time on the effectiveness of an intervention. This paper presents a review of 12 studies (or protocols) that use (or plan to use) a stepped wedge design. One aim of the review is to highlight the potential for the stepped wedge design, given its infrequent use to date. METHODS: Comprehensive literature review of studies or protocols using a stepped wedge design. Data were extracted from the studies in three categories for subsequent consideration: study information (epidemiology, intervention, number of participants), reasons for using a stepped wedge design and methods of data analysis. RESULTS: The 12 studies included in this review describe evaluations of a wide range of interventions, across different diseases in different settings. However the stepped wedge design appears to have found a niche for evaluating interventions in developing countries, specifically those concerned with HIV. There were few consistent motivations for employing a stepped wedge design or methods of data analysis across studies. The methodological descriptions of stepped wedge studies, including methods of randomisation, sample size calculations and methods of analysis, are not always complete. CONCLUSION: While the stepped wedge design offers a number of opportunities for use in future evaluations, a more consistent approach to reporting and data analysis is required
Implementation of contemporary chemotherapy for patients with metastatic pancreatic ductal adenocarcinoma: a population-based analysis
Background: Positive results of randomized trials led to the introduction of FOLFIRINOX in 2012 and gemcitabine with nab-paclitaxel in 2015 for patients with metastatic pancreatic ductal adenocarcinoma. It is unknown to which extent these new chemotherapeutic regimens have been implemented in clinical practice and what the impact has been on overall survival. Material and methods: Patients diagnosed with metastatic pancreatic ductal adenocarcinoma between 2007–2016 were included from the population-based Netherlands Cancer Registry. Multilevel logistic regression and Cox regression analyses, adjusting for patient, tumor, and hospital characteristics, were used to analyze variation of chemotherapy use. Results: In total, 8726 patients were included. The use of chemotherapy increased from 31% in 2007–2011 to 37% in 2012–2016 (p <.001). Variation in the use of any chemotherapy between centers decreased (adjusted range 2007–2011: 12–67%, 2012–2016: 20–54%) whereas overall survival increased from 5.6 months to 6.4 months (p <.001) for patients treated with chemotherapy. Use of FOLFIRINOX and gemcitabine with nab-paclitaxel varied widely in 2015–2016, but both showed a more favorable overall survival compared to gemcitabine monotherapy (median 8.0 vs. 7.0 vs. 3.8 months, respectively). In the period 2015–2016, FOLFIRINOX was used in 60%, gemcitabine with nab-paclitaxel in 9.7% and gemcitabine monotherapy in 25% of patients receiving chemotherapy. Conclusion: Nationwide variation in the use of chemotherapy decreased after the implementation of FOLFIRINOX and gemcitabine with nab-paclitaxel. Still a considerable proportion of patients receives gemcitabine monotherapy. Overall survival did improve, but not clinically relevant. These results emphasize the need for a structured implementation of new chemotherapeutic regimens
Population-based impact of COVID-19 on incidence, treatment, and survival of patients with pancreatic cancer
Background: The COVID-19 pandemic has put substantial strain on the healthcare system of which the effects are only partly elucidated. This study aimed to investigate the impact on pancreatic cancer care. Methods: All patients diagnosed with pancreatic cancer between 2017 and 2020 were selected from the Netherlands Cancer Registry. Patients diagnosed and/or treated in 2020 were compared to 2017–2019. Monthly incidence was calculated. Patient, tumor and treatment characteristics were analyzed and compared using Chi-squared tests. Survival data was analyzed using Kaplan–Meier and Log-rank tests. Results: In total, 11019 patients were assessed. The incidence in quarter (Q)2 of 2020 was comparable with that in Q2 of 2017–2019 (p = 0.804). However, the incidence increased in Q4 of 2020 (p = 0.031), mainly due to a higher incidence of metastatic disease (p = 0.010). Baseline characteristics, surgical resection (15% vs 16%; p = 0.466) and palliative systemic therapy rates (23% vs 24%; p = 0.183) were comparable. In 2020, more surgically treated patients received (neo)adjuvant treatment compared to 2017–2019 (73% vs 67%; p = 0.041). Median overall survival was comparable (3.8 vs 3.8 months; p = 0.065). Conclusion: This nationwide study found a minor impact of the COVID-19 pandemic on pancreatic cancer care and outcome. The Dutch health care system was apparently able to maintain essential care for patients with pancreatic cancer
Correction:Recurrent disease detection after resection of pancreatic ductal adenocarcinoma using a recurrence-focused surveillance strategy (RADAR-PANC): protocol of an international randomized controlled trial according to the Trials within Cohorts design
Correction:Recurrent disease detection after resection of pancreatic ductal adenocarcinoma using a recurrence-focused surveillance strategy (RADAR-PANC): protocol of an international randomized controlled trial according to the Trials within Cohorts design
The Efficacy of Pharmacotherapy for Decreasing the Expansion Rate of Abdominal Aortic Aneurysms: A Systematic Review and Meta-Analysis
BACKGROUND: Pharmacotherapy may represent a potential means to limit the expansion rate of abdominal aortic aneurysms (AAAs). Studies evaluating the efficacy of different pharmacological agents to slow down human AAA-expansion rates have been performed, but they have never been systematically reviewed or summarized. METHODS AND FINDINGS: Two independent reviewers identified studies and selected randomized trials and prospective cohort studies comparing the growth rate of AAA in patients with pharmacotherapy vs. no pharmacotherapy. We extracted information on study interventions, baseline characteristics, methodological quality, and AAA growth rate differences (in mm/year). Fourteen prospective studies met eligibility criteria. Five cohort studies raised the possibility of benefit of beta-blockers [pooled growth rate difference: -0.62 mm/year, (95%CI, -1.00 to -0.24)], but this was not confirmed in three beta-blocker RCTs [pooled RCT growth rate difference: -0.05 mm/year (-0.16 to 0.05)]. Statins have been evaluated in two cohort studies that yield a pooled growth rate difference of -2.97 (-5.83 to -0.11). Doxycycline and roxithromycin have been evaluated in two RCTs that suggest possible benefit [pooled RCT growth rate difference: -1.32 mm/year (-2.89 to 0.25)]. Studies assessing NSAIDs, diuretics, calcium channel blockers and ACE inhibitors, meanwhile, did not find statistically significant differences. CONCLUSIONS: Beta-blockers do not appear to significantly reduce the growth rate of AAAs. Statins and other anti-inflammatory agents appear to hold promise for decreasing the expansion rate of AAA, but need further evaluation before definitive recommendations can be made
Conditional Survival After Resection for Pancreatic Cancer: A Population-Based Study and Prediction Model
Background: Conditional survival is the survival probability after already surviving a predefined time period. This may be informative during follow-up, especially when adjusted for tumor characteristics. Such prediction models for patients with resected pancreatic cancer are lacking and therefore conditional survival was assessed and a nomogram predicting 5-year survival at a predefined period after resection of pancreatic cancer was developed. Methods: This population-based study included patients with resected pancreatic ductal adenocarcinoma from the Netherlands Cancer Registry (2005–2016). Conditional survival was calculated as the median, and the probability of surviving up to 8 years in patients who already survived 0–5 years after resection was calculated using the Kaplan–Meier method. A prediction model was constructed. Results: Overall, 3082 patients were included, with a median age of 67 years. Median overall survival was 18 months (95% confidence interval 17–18 months), with a 5-year survival of 15%. The 1-year conditional survival (i.e. probability of surviving the next year) increased from 55 to 74 to 86% at 1, 3, and 5 years after surgery, respectively, while the median overall survival increased from 15 to 40 to 64 months at 1, 3, and 5 years after surgery, respectively. The prediction model demonstrated that the probability of achieving 5-year survival at 1 year after surgery varied from 1 to 58% depending on patient and tumor characteristics. Conclusions: This population-based study showed that 1-year conditional survival was 55% 1 year after resection and 74% 3 years after resection in patients with pancreatic cancer. The prediction model is available via www.pancreascalculator.com to inform patients and caregivers
Nationwide trends in incidence, treatment and survival of pancreatic ductal adenocarcinoma
Background: In recent years, new treatment options have become available for pancreatic ductal adenocarcinoma (PDAC) including 5-fluorouracil, leucovorin, irinotecan and oxaliplatin. The impact hereof has not been assessed in nationwide cohort studies. This population-based study aimed to investigate nationwide trends in incidence, treatment and survival of PDAC. Materials and methods: Patients wi
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