On 26 September 2022, the Double Asteroid Redirection Test (DART) spacecraft struck Dimorphos, a satellite of the asteroid 65803 Didymos1. Because it is a binary system, it is possible to determine how much the orbit of the satellite changed, as part of a test of what is necessary to deflect an asteroid that might threaten Earth with an impact. In nominal cases, pre-impact predictions of the orbital period reduction ranged from roughly 8.8 to 17 min (refs. 2,3). Here we report optical observations of Dimorphos before, during and after the impact, from a network of citizen scientists’ telescopes across the world. We find a maximum brightening of 2.29 ± 0.14 mag on impact. Didymos fades back to its pre-impact brightness over the course of 23.7 ± 0.7 days. We estimate lower limits on the mass contained in the ejecta, which was 0.3–0.5% Dimorphos’s mass depending on the dust size. We also observe a reddening of the ejecta on impact.

Incentivising has shown to improve participation in clinical trials. However, ethical concerns suggest that incentives may be coercive, obscure trial risks and encourage individuals to enrol in clinical trials for the wrong reasons. The aim of our study was to develop and pilot a discrete choice experiment (DCE) to explore and identify preferences for incentives. A DCE was designed by including following attributes (and levels) of incentives: value, method, and time involvement. To account for trial benefit and risk, each was included as an attribute with levels low, medium and high. For testing purposes, the DCE was administrated using SurveyMonkey in a population of third level students. A total of 245 students, representative of the general student population, participated in the online DCE. The results provide a template to assess and explore the use of different incentive methods in clinical trials. The template can be used in its current format or adapted to particular scenarios. This pilot study provides a feasible methodology to explore the use of incentives for participation in clinical trials and can be adapted to specific trial requirements to provide information for ethical applications or identify the most favourable incentive for participation in clinical trials.

No abstract

The clinical scoring system used did not reduce the variability of assessment of dehydration compared to doctors' conventional methods. In order to reduce variability improving education may be more important than production of a scoring system as experience appears to be a key determinant in the assessment of a potentially dehydrated child.

This document and trademark(s) contained herein are protected by law. This representation of RAND intellectual property is provided for noncommercial use only. Unauthorized posting of this publication online is prohibited. Permission is given to duplicate this document for personal use only, as long as it is unaltered and complete. Permission is required from RAND to reproduce, or reuse in another form, any of its research documents for commercial use. For information on reprint and linking permissions, please visit www.rand.org/pubs/permissions. The RAND Corporation is a research organization that develops solutions to public policy challenges to help make communities throughout the world safer and more secure, healthier and more prosperous. RAND is nonprofit, nonpartisan, and committed to the public interest.RAND's publications do not necessarily reflect the opinions of its research clients and sponsors. Support RANDMake a tax-deductible charitable contribution at