A dehydrated space-weathered skin cloaking the hydrated interior of Ryugu

Without a protective atmosphere, space-exposed surfaces of airless Solar System bodies gradually experience an alteration in composition, structure and optical properties through a collective process called space weathering. The return of samples from near-Earth asteroid (162173) Ryugu by Hayabusa2 provides the first opportunity for laboratory study of space-weathering signatures on the most abundant type of inner solar system body: a C-type asteroid, composed of materials largely unchanged since the formation of the Solar System. Weathered Ryugu grains show areas of surface amorphization and partial melting of phyllosilicates, in which reduction from Fe3+ to Fe2+ and dehydration developed. Space weathering probably contributed to dehydration by dehydroxylation of Ryugu surface phyllosilicates that had already lost interlayer water molecules and to weakening of the 2.7 µm hydroxyl (–OH) band in reflectance spectra. For C-type asteroids in general, this indicates that a weak 2.7 µm band can signify space-weathering-induced surface dehydration, rather than bulk volatile loss

Specialty choice and understanding of primary care among Japanese medical students

To assess specialty choice and understanding of primary care among Japanese medical students, all students from seven Japanese medical schools (three public and four private) were surveyed, using a written questionnaire. A total of 3377 students provided data for the study. Of the students surveyed, 89.8% wanted to become clinicians, and 79.3% wanted to have general clinical ability. About half of the respondents, 5494 replied that they had some, or great, interest in primary care, but it was found that their understanding of primary care was inadequate. Almost half (56.3%) of the students answered that they had some idea of what a general practitioner did. This proportion was nearly the same through all years of medical school. While 1245 (36.9%) students (most of them in the fifth or sixth year) replied that they had received some linical training while working in hospitals, only 203 (6.0%) students had worked in private clinics (the sites where most primary care is still provided), and 129 (3.8%) students had experience in providing home visits and home care. An even greater number, 64.3%, replied that they had inadequate information about the career options available to them. The study found that although many Japanese medical students want to obtain broad clinical competence, their understanding of primary care is insufficient. In order to increase the number of primary care providers the system of medical education in Japan must provide primary care doctors to act as role models, and must make available information about postgraduate primary care programmes. These programmes need to be increased, as do rewarding positions for programme graduates