198 research outputs found

    Sustainable inland transportation

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    Inland navigation is often mentioned as a ‘green’ alternative for the two other main inland transport modes: rail and road transport. In order to investigate the opportunities for inland navigation we first analyze the competitive position of inland navigation vis-àvis the other main inland transport modes. For that, we perform a comparative study on the current sustainability performance of the three modes. Second, through a case study, we analyze a recent initiative for sustainable innovation of inland navigation in order to assess the barriers and opportunities for improving the competitive position of sustainable inland navigation

    Semiparametric theory and empirical processes in causal inference

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    In this paper we review important aspects of semiparametric theory and empirical processes that arise in causal inference problems. We begin with a brief introduction to the general problem of causal inference, and go on to discuss estimation and inference for causal effects under semiparametric models, which allow parts of the data-generating process to be unrestricted if they are not of particular interest (i.e., nuisance functions). These models are very useful in causal problems because the outcome process is often complex and difficult to model, and there may only be information available about the treatment process (at best). Semiparametric theory gives a framework for benchmarking efficiency and constructing estimators in such settings. In the second part of the paper we discuss empirical process theory, which provides powerful tools for understanding the asymptotic behavior of semiparametric estimators that depend on flexible nonparametric estimators of nuisance functions. These tools are crucial for incorporating machine learning and other modern methods into causal inference analyses. We conclude by examining related extensions and future directions for work in semiparametric causal inference

    Quantitative models for reverse logistics

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    This article surveys the recently emerged field of reverse logistics. The management of return flows induced by the various forms of reuse of products and materials in industrial production processes has received growing attentio

    Logistiek Biobased Economy: toekomstbeelden 2025 & agenda 2013-2017

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    Naast de afzetmogelijkheden van biobased producten (markten) en de technologische verwerkingsmogelijkheden, bepalen de beschikbaarheid, handel en logistiek in sterke mate de wijze waarop de biobased economy in Nederland zich zal ontwikkelen. Het is noodzakelijk in de komende jaren duurzame, economisch rendabele logistieke biomassaketens op te zetten. Op dit terrein bestaat nog veel onduidelijkheid. Het doel van het project is het vormen van: gedragen toekomstbeelden van de logistiek in de biobased economy in 2025 en een gedragen agenda met actiepunten voor 2013-2017 (ofwel waarmee moeten we starten in de eerstkomende 5 jaar om de toekomstbeelden te bereiken)

    Multicenter experience of upper extremity access in complex endovascular aortic aneurysm repair

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    Purpose: Upper extremity access (UEA) for antegrade cannulation of aortic side branches is a relevant part of endovascular treatment of complex aortic aneurysms and can be achieved using several techniques, sites, and sides. The purpose of this study was to evaluate different UEA strategies in a multicenter registry of complex endovascular aortic aneurysm repair (EVAR). Methods: In six aortic centers in the Netherlands, all endovascular aortic procedures from 2006 to 2019 were retrospectively reviewed. Patients who received UEA during complex EVAR were included. The primary outcome was a composite end point of any access complication, excluding minor hematomas. Secondary outcomes were access characteristics, access complications considered individually, access reinterventions, and incidence of ischemic cerebrovascular events. Results: A total of 417 patients underwent 437 UEA for 303 fenestrated/branched EVARs and 114 chimney EVARs. Twenty patients had bilateral, 295 left-sided, and 102 right-sided UEA. A total of 413 approaches were performed surgically and 24 percutaneously. Distal brachial access (DBA) was used in 89 cases, medial brachial access (MBA) in 149, proximal brachial access (PBA) in 140, and axillary access (AA) in 59 cases. No significant differences regarding the composite end point of access complications were seen (DBA: 11.3% vs MBA: 6.7% vs PBA: 13.6% vs AA: 10.2%; P =.29). Postoperative neuropathy occurred most after PBA (DBA: 1.1% vs MBA: 1.3% vs PBA: 9.3% vs AA: 5.1%; P =.003). There were no differences in cerebrovascular complications between access sides (right: 5.9% vs left: 4.1% vs bilateral: 5%; P =.75). Significantly more overall access complications were seen after a percutaneous approach (29.2% vs 6.8%; P =.002). In multivariate analysis, the risk for access complications after an open approach was decreased by male sex (odds ratio [OR]: 0.27; 95% confidence interval [CI]: 0.10-0.72; P =.009), whereas an increase in age per year (OR: 1.08; 95% CI: 1.004-1.179; P =.039) and diabetes mellitus type 2 (OR: 3.70; 95% CI: 1.20-11.41; P =.023) increased the risk. Conclusions: Between the four access localizations, there were no differences in overall access complications. Female sex, diabetes mellitus type 2, and aging increased the risk for access complications after a surgical approach. Furthermore, a percutaneous UEA resulted in higher complication rates than a surgical approach

    Results from a nationwide prospective registry on open surgical or endovascular repair of juxtarenal abdominal aortic aneurysms

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    Background: Juxtarenal abdominal aortic aneurysms (JRAAAs) can be treated either with open surgical repair (OSR) including suprarenal clamping or by complex endovascular aneurysm repair (cEVAR). In this study, we present the comparison between the short-term mortality and complications of the elective JRAAA treatment modalities from a national database reflecting daily practice in the Netherlands. Methods: All patients undergoing elective JRAAA open repair or cEVAR (fenestrated EVAR or chimney EVAR) between January 2016 and December 2018 registered in the Dutch Surgical Aneurysm Audit (DSAA) were eligible for inclusion. Descriptive perioperative variables and outcomes were compared between patients treated with open surgery or endovascularly. Adjusted odds ratios for short-term outcomes were calculated by logistic regression analysis. Results: In all, 455 primary treated patients with JRAAAs could be included (258 OSR, 197 cEVAR). Younger patients and female patients were treated more often with OSR vs cEVAR (72 ± 6.1 vs 76 ± 6.0; P < .001 and 22% vs 15%; P = .047, respectively). Patients treated with OSR had significantly more major and minor complications as well as a higher chance of early mortality (OSR vs cEVAR, 45% vs 21%; P < .001; 34% vs 23%; P = .011; and 6.6% vs 2.5%; P = .046, respectively). After logistic regression with adjustment for confounders, patients who were treated with OSR showed an odds ratio of 3.64 (95% confidence interval [CI], 2.25-5.89; P < .001) for major complications compared with patients treated with cEVAR, and for minor complications, the odds ratios were 2.17 (95% CI, 1.34-3.53; P = .002) higher. For early mortality, the odds ratios were 3.79 (95% CI, 1.26-11.34; P = .017) higher after OSR compared with cEVAR. Conclusions: In this study, after primary elective OSR for JRAAA, the odds for major complications, minor complications, and short-term mortality were significantly higher compared with cEVAR

    The influence of multidisciplinary team meetings on treatment decisions in advanced bladder cancer

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    Objectives: To investigate the role of specialised genitourinary multidisciplinary team meetings (MDTMs) in decision-making and identify factors that influence the probability of receiving a treatment plan with curative intent for patients with muscle invasive bladder cancer (MIBC). Patients and methods: Data relating to patients with cT2-4aN0/X-1 M0 urothelial cell carcinoma, diagnosed between November 2017 and October 2019, were selected from the nationwide, population-based Netherlands Cancer Registry (‘BlaZIB study’). Curative treatment options were defined as radical cystectomy (RC) with or without neoadjuvant chemotherapy, chemoradiation or brachytherapy. Multilevel logistic regression analyses were used to examine the association between MDTM factors and curative treatment advice and how this advice was followed. Results: Of the 2321 patients, 2048 (88.2%) were discussed in a genitourinary MDTM. Advanced age (&gt;80 years) and poorer World Health Organization performance status (score 1–2 vs 0) were associated with no discussion (P &lt; 0.001). Being discussed was associated with undergoing treatment with curative intent (odds ratio [OR] 3.0, 95% confidence interval [CI] 1.9–4.9), as was the involvement of a RC hospital (OR 1.70, 95% CI 1.09–2.65). Involvement of an academic centre was associated with higher rates of bladder-sparing treatment (OR 2.05, 95% CI 1.31–3.21). Patient preference was the main reason for non-adherence to treatment advice. Conclusions: For patients with MIBC, the probability of being discussed in a MDTM was associated with age, performance status and receiving treatment with curative intent, especially if a representative of a RC hospital was present. Future studies should focus on the impact of MDTM advice on survival data.</p

    The influence of multidisciplinary team meetings on treatment decisions in advanced bladder cancer

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    Objectives: To investigate the role of specialised genitourinary multidisciplinary team meetings (MDTMs) in decision-making and identify factors that influence the probability of receiving a treatment plan with curative intent for patients with muscle invasive bladder cancer (MIBC). Patients and methods: Data relating to patients with cT2-4aN0/X-1 M0 urothelial cell carcinoma, diagnosed between November 2017 and October 2019, were selected from the nationwide, population-based Netherlands Cancer Registry (‘BlaZIB study’). Curative treatment options were defined as radical cystectomy (RC) with or without neoadjuvant chemotherapy, chemoradiation or brachytherapy. Multilevel logistic regression analyses were used to examine the association between MDTM factors and curative treatment advice and how this advice was followed. Results: Of the 2321 patients, 2048 (88.2%) were discussed in a genitourinary MDTM. Advanced age (&gt;80 years) and poorer World Health Organization performance status (score 1–2 vs 0) were associated with no discussion (P &lt; 0.001). Being discussed was associated with undergoing treatment with curative intent (odds ratio [OR] 3.0, 95% confidence interval [CI] 1.9–4.9), as was the involvement of a RC hospital (OR 1.70, 95% CI 1.09–2.65). Involvement of an academic centre was associated with higher rates of bladder-sparing treatment (OR 2.05, 95% CI 1.31–3.21). Patient preference was the main reason for non-adherence to treatment advice. Conclusions: For patients with MIBC, the probability of being discussed in a MDTM was associated with age, performance status and receiving treatment with curative intent, especially if a representative of a RC hospital was present. Future studies should focus on the impact of MDTM advice on survival data.</p

    Prediction of huge X-ray Faraday rotation at the Gd N_4,5 threshold

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    X-ray absorption spectra in a wide energy range around the 4d-4f excitation threshold of Gd were recorded by total electron yield from in-plane magnetized Gd metal films. Matching the experimental spectra to tabulated absorption data reveals unprecedented short light absorption lengths down to 3 nm. The associated real parts of the refractive index for circularly polarized light propagating parallel or antiparallel to the Gd magnetization, determined through the Kramers-Kronig transformation, correspond to a magneto-optical Faraday rotation of 0.7 degrees per atomic layer. This finding shall allow the study of magnetic structure and magnetization dynamics of lanthanide elements in nanosize systems and dilute alloys.Comment: 4 pages, 2 figures, final version resubmitted to Phys. Rev. B, Brief Reports. Minor change
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