Child labour or school attendance? Evidence from Zambia

In this paper we investigate what affects school attendance and child labour in an LDC, using data for Zambia. Since the data comes from a household survey with information on all household members it allows us to take account of unobserved household effects by introducing household-specific effects in a logit model. The empirical analysis suggests that both economic and sociological variables are important determinants for the choice between school attendance and child labour. In particular, we find some support for the hypothesis that poverty forces households to keep their children away from school. JEL classification: J24, I21, O15Child labour · human capital · household-specific effects

Flexydos3D : a new deformable anthropomorphic 3D dosimeter readout with optical CT scanning

A new deformable polydimethylsiloxane (PDMS) based dosimeter is proposed that can be cast in an anthropomorphic shape and that can be used for 3D radiation dosimetry of deformable targets. The new material has additional favorable characteristics as it is tissue equivalent for high-energy photons, easy to make and is non-toxic. In combination with dual wavelength optical scanning, it is a powerful dosimeter for dose verification of image gated or organ tracked radiotherapy with moving and deforming targets.4 page(s

Towards range-guidance in proton therapy to detect organ motion-induced dose degradations

Introduction: Internal organ motion and deformations may cause dose degradations in proton therapy (PT) that are challenging to resolve using conventional image-guidance strategies. This study aimed to investigate the potential of range guidance using water-equivalent path length (WEPL) calculations to detect dose degradations occurring in PT. Materials and methods: Proton ranges were estimated using WEPL calculations. Field-specific isodose surfaces in the planning CT (pCT), from robustly optimised five-field proton plans (opposing lateral and three posterior/posterior oblique beams) for locally advanced prostate cancer patients, were used as starting points. WEPLs to each point on the field-specific isodoses in the pCT were calculated. The corresponding range for each point was found in the repeat CTs (rCTs). The spatial agreement between the resulting surfaces in the rCTs (hereafter referred to as iso-WEPLs) and the isodoses re-calculated in rCTs was evaluated for different dose levels and Hausdorff thresholds (2–5 mm). Finally, the sensitivity and specificity of detecting target dose degradation (V95% < 95%) using spatial agreement measures between the iso-WEPLs and isodoses in the pCT was evaluated. Results: The spatial agreement between the iso-WEPLs and isodoses in the rCTs depended on the Hausdorff threshold. The agreement was 65%–88% for a 2 mm threshold, 83%–96% for 3 mm, 90%–99% for 4 mm, and 94%–99% for 5 mm, across all fields and isodose levels. Minor differences were observed between the different isodose levels investigated. Target dose degradations were detected with 82%–100% sensitivity and 75%–80% specificity using a 2 mm Hausdorff threshold for the lateral fields. Conclusion: Iso-WEPLs were comparable to isodoses re-calculated in the rCTs. The proposed strategy could detect target dose degradations occurring in the rCTs and could be an alternative to a fully-fledged dose re-calculation to detect anatomical variations severely influencing the proton range.publishedVersio