Cosmic dust impacts on the Hubble Space Telescope.

Exposure of the Hubble Space Telescope to space in low Earth orbit resulted in numerous hypervelocity impacts by cosmic dust (micrometeoroids) and anthropogenic particles (orbital debris) on the solar arrays and the radiator shield of the Wide Field and Planetary Camera 2, both subsequently returned to Earth. Solar cells preserve residues from smaller cosmic dust (and orbital debris) but give less reliable information from larger particles. Here, we present images and analyses from electron, ion and X-ray fluorescence microscopes for larger impact features (millimetre- to centimetre-scale) on the radiator shield. Validated by laboratory experiments, these allow interpretation of composition, probable origin and likely dimensions of the larger impactors. The majority (~90%) of impacts by grains greater than 50 µm in size were made by micrometeoroids, dominated by magnesium- and iron-rich silicates and iron sulfides, metallic iron-nickel and chromium-rich spinel similar to that in ordinary chondrite meteorites of asteroid origin. Our re-evaluation of the largest impact features shows substantially fewer large orbital debris impacts than reported by earlier authors. Mismatch to the NASA ORDEM and ESA MASTER models of particle populations in orbit may be partly due to model overestimation of orbital debris flux and underestimation of larger micrometeoroid numbers. This article is part of the theme issue 'Dust in the Solar System and beyond'.

Hospital resource endowments and nosocomial infections: longitudinal evidence from the English National Health Service on Clostridioides difficile between 2011 and 2019.

OBJECTIVES: To identify key factors associated with Clostridioides difficile infections (CDIs) in healthcare at the hospital organization level. DESIGN: Longitudinal study covering the period 2011-2019. Hospital reports were analysed to determine the number of CDIs and several hospital-related environmental factors: financial resources (i.e., cleaning expenditure), spatial resources (i.e., number of single rooms with a private bathroom), human resources (i.e., number of physicians and nursing staff) and cultural resources (i.e., error reporting climate). The relationships between the environmental factors and CDIs were analysed in a hybrid within- and between-hospital random-effect model. SETTING: A total of 129 general hospital Trusts operating in the English National Health Service (NHS). PARTICIPANTS: All inpatients in 129 general hospital trusts of the NHS in the years 2011-2019, covering 120,629 cases of CDI. MAIN OUTCOME MEASURE: Annual number of CDIs per hospital trust. RESULTS: Single rooms were associated with fewer CDIs at the within-hospital level, but not at the between-hospital level. Similarly, more nursing staff was associated with fewer CDIs at the within-hospital level, but not at the between-hospital level. This effect was not observed for physician staffing. A different picture emerged for the protective effect of cultural resources, with a weakly significant effect of between-hospital differences, but no within-hospital effect. Financial resources were not associated with CDIs either between hospitals or within them over time. CONCLUSIONS: The present study identified hospital resources with a beneficial influence on CDI rates. Healthcare organizations can use this knowledge for active CDI prevention.

[The impact of research and development on hospital performance - an empirical analysis in the English hospital sector]. / Der Einfluss von Forschung und Entwicklung auf den Krankenhauserfolg - eine empirische Analyse im englischen Krankenhauswesen.

The aim of the present study is to investigate empirically whether research and development (R&D) in hospitals positively affect their economic and clinical performance. For this purpose, data on R&D (external grants, research projects, publications) and on hospital performance (risk-adjusted mortality, patient satisfaction, official quality rating, annual surplus, turnover per bed, waiting times) were collected in the context of English acute health-care delivery and analysed using multiple regression analyses. Empirical results suggest a positive relationship between R&D and clinical performance, but do not support the existence of such a relationship between R&D and economic performance. The results suggest that, in the hospital sector, R&D are aimed primarily at achieving clinical goals, whereas economic goals are only of secondary relevance.