On the origin and evolution of the asteroid Ryugu: A comprehensive geochemical perspective

Presented here are the observations and interpretations from a comprehensive analysis of 16 representative particles returned from the C-type asteroid Ryugu by the Hayabusa2 mission. On average Ryugu particles consist of 50% phyllosilicate matrix, 41% porosity and 9% minor phases, including organic matter. The abundances of 70 elements from the particles are in close agreement with those of CI chondrites. Bulk Ryugu particles show higher δ18O, Δ17O, and ε54Cr values than CI chondrites. As such, Ryugu sampled the most primitive and least-thermally processed protosolar nebula reservoirs. Such a finding is consistent with multi-scale H-C-N isotopic compositions that are compatible with an origin for Ryugu organic matter within both the protosolar nebula and the interstellar medium. The analytical data obtained here, suggests that complex soluble organic matter formed during aqueous alteration on the Ryugu progenitor planetesimal (several 10’s of km), <2.6 Myr after CAI formation. Subsequently, the Ryugu progenitor planetesimal was fragmented and evolved into the current asteroid Ryugu through sublimation

Understanding Parental Perceptions of Content-Specific Barriers to Preventing Unintentional Injuries in the Home

Background: Preventable injuries are the leading cause of death in children around the world, including in Japan. As children under the age of 5 years spend most of their time at home, home injury prevention is critical for child safety. The purpose of this study was to identify specific, focused, and precise barriers against injury prevention practice. Methods: We conducted an online survey to examine the barriers faced by parents when taking actions to prevent home injuries. Results: The results revealed common reasons why parents do not or cannot take a recommended action across injury types, and that the magnitude of importance for a specific barrier depends on the type of injury. Conclusions: Identifying content-specific barriers could help researchers and educators understand parents’ needs, discuss what barriers are more important than others by injury type, and develop effective strategies based on the 3Es of injury prevention (enforcement, engineering, and education)

Childhood-home-injury-situation Simulation Adaptable to an Individual Environment Based on Child Physical Model and Injury Semantic Structure Database

AbstractMost accidents involving children below the age of five occur within their homes. Since it is important to maintain a safe home environment for children, it is imperative to be able to predict what kinds of accidents may occur in a particular environment, and then to find ways to improve that environment. However, the various and scattered statistical data sources and scientific knowledge related to accident prediction have not been structured for integrative utilization. In this paper, the authors report on the development of a new simulation technology that can be used to predict the kinds of accidents that may occur in a particular environment by means of a hybrid memory- and model-based approach. The system consists of a graph-structuralized accident database created from large-scale accident data (which enables the memory-based approach), and a development behavior model which describes the statistical relationship between a body interaction abilities and the age of children