As illustrated by the Global Financial Crisis and the more recent Covid-19 pandemic, when asset prices fall, margin levels increase and highly leveraged financial institutions are forced to... Show moreAs illustrated by the Global Financial Crisis and the more recent Covid-19 pandemic, when asset prices fall, margin levels increase and highly leveraged financial institutions are forced to deleverage, causing market participants to ‘run’ in advance of other market participants motivated to do exactly the same thing. As a result, a vicious cycle can emerge where lenders raise margin levels thereby demanding more financial collateral, forcing de-leveraging and more asset fire sales, eventually generating a downward leverage and liquidity spiral. The source of this instability is a recurring phenomenon involving the build-up of leverage that makes the economy particularly vulnerable to financial crises.My dissertation investigates the use of collateral transactions in the shadow banking sector. In particular, it will argue for the introduction of more stringent margin measures to tame financial uncertainty by limiting leverage and dampen procyclicality. One plausible way to restrict leverage is to impose minimum margin regulation, which would ex-ante limit the amount of leverage a financial institution can obtain. This dissertation will therefore propose four complementary measures that would ultimately result in a harmonised legal and regulatory margin framework in the EU shadow banking sector. Show less
Introduction: With the introduction of accelerated partial breast irradiation (APBI) and the trend of reducing the number of fractions, the geometric accuracy of treatment delivery becomes critical... Show moreIntroduction: With the introduction of accelerated partial breast irradiation (APBI) and the trend of reducing the number of fractions, the geometric accuracy of treatment delivery becomes critical. APBI patient setup is often based on fiducials, as the seroma is frequently not visible on pretreatment imaging. We assessed the motion of fiducials relative to the tumor bed between planning CT and treatment, and calculated margins to compensate for this motion. Methods: A cohort of seventy patients treated with APBI on a Cyberknife was included. Planning and in room pretreatment CT scans were registered on the tumor bed. Residual motion of the centers of mass of surgical clips and interstitial gold markers was calculated. We calculated the margins required per desired percentage of patients with 100% CTV coverage, and the systematic and random errors for fiducial motion. Results: For a single fraction treatment, a margin of 1.8 mm would ensure 100% CTV coverage in 90% of patients when using surgical clips for patient set-up. When using interstitial markers, the margin should be 2.2 mm. The systematic and random errors were 0.46 mm for surgical clip motion and 0.60 mm for interstitial marker motion. No clinical factors were found predictive for fiducial motion. Conclusions: Fiducial motion relative to the tumor bed between planning CT and APBI treatment is non negligible and should be included in the PTV margin calculation to prevent geographical miss. Systematic and random errors of fiducial motion were combined with other geometric uncertainties to calculate comprehensive PTV margins for different treatment techniques. (c) 2021 The Authors. Published by Elsevier B.V. Radiotherapy and Oncology 163 (2021) 1-6 This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Show less
Rueten-Budde, A.J.; Praag, V.M. van; Sande, M.A.J. van de; Fiocco, M.; PERSARC Studygrp 2018
