Oxygen isotopic evidence for accretion of Earth's water before a high-energy Moon-forming giant impact

The Earth-Moon system likely formed as a result of a collision between two large planetary objects. Debate about their relative masses, the impact energy involved, and the extent of isotopic homogenization continues. We present the results of a high-precision oxygen isotope study of an extensive suite of lunar and terrestrial samples. We demonstrate that lunar rocks and terrestrial basalts show a 3 to 4 ppm (parts per million), statistically resolvable, difference in D17O. Taking aubrite meteorites as a candidate impactor material, we show that the giant impact scenario involved nearly complete mixing between the target and impactor. Alternatively, the degree of similarity between the D17O values of the impactor and the proto-Earth must have been significantly closer than that between Earth and aubrites. If the Earth-Moon system evolved from an initially highly vaporized and isotopically homogenized state, as indicated by recent dynamical models, then the terrestrial basalt-lunar oxygen isotope difference detected by our study may be a reflection of post-giant impact additions to Earth. On the basis of this assumption, our data indicate that post-giant impact additions to Earth could have contributed between 5 and 30% of Earth's water, depending on global water estimates. Consequently, our data indicate that the bulk of Earth's water was accreted before the giant impact and not later, as often proposed

The Broadband XMM-Newton and NuSTAR X-ray Spectra of Two Ultraluminous X-ray Sources in the Galaxy IC 342

We present results for two Ultraluminous X-ray Sources (ULXs), IC 342 X-1 and IC 342 X-2, using two epochs of XMM-Newton and NuSTAR observations separated by $\sim$7 days. We observe little spectral or flux variability above 1 keV between epochs, with unabsorbed 0.3--30 keV luminosities being $1.04^{+0.08}_{-0.06} \times 10^{40}$ erg s$^{-1}$ for IC 342 X-1 and $7.40\pm0.20 \times 10^{39}$ erg s$^{-1}$ for IC 342 X-2, so that both were observed in a similar, luminous state. Both sources have a high absorbing column in excess of the Galactic value. Neither source has a spectrum consistent with a black hole binary in low/hard state, and both ULXs exhibit strong curvature in their broadband X-ray spectra. This curvature rules out models that invoke a simple reflection-dominated spectrum with a broadened iron line and no cutoff in the illuminating power-law continuum. X-ray spectrum of IC 342 X-1 can be characterized by a soft disk-like black body component at low energies and a cool, optically thick Comptonization continuum at high energies, but unique physical interpretation of the spectral components remains challenging. The broadband spectrum of IC 342 X-2 can be fit by either a hot (3.8 keV) accretion disk, or a Comptonized continuum with no indication of a seed photon population. Although the seed photon component may be masked by soft excess emission unlikely to be associated with the binary system, combined with the high absorption column, it is more plausible that the broadband X-ray emission arises from a simple thin blackbody disk component. Secure identification of the origin of the spectral components in these sources will likely require broadband spectral variability studies.Comment: 12 pages, 11 figures, 5 Tables, Accepted for publication in The Astrophysical Journa

Adolescent health: A rural community's approach

Open accessIntroduction: Significant health problems encountered in adulthood often have their roots in health behaviours initiated during adolescence. In order to reverse this trend, school and health personnel, as well as parents and other community members working with high school students, need to be aware of the health-related beliefs and choices that guide the behaviours of teenagers. Although a wide variety of research has been conducted on this topic among urban adolescents, less is known about the health beliefs and behaviors of adolescents residing in rural areas, particularly in Canada. In general, rural Canadians are less healthy than their urban counterparts. Building on the knowledge and understanding of their own community, key stakeholders were invited to engage in the design and implementation of a participatory action research project aimed at understanding and improving the health of rural adolescents. Methods: A group of parents, teachers, students, school administrators and public health nurses engaged in a participatory action research project to better understand determinants of the health of rural adolescents at a high school in Western Canada. Group members developed and administered a health survey to 288 students from a small rural high school, in an effort to identify areas of concern and interest regarding health practices and beliefs of rural adolescents, and to take action on these identified concerns. Results: Results indicated some interesting but potentially worrying trends in this population. For example, while frequent involvement in a physical activity was noted by 75.9% of participants, close to half of the females (48%) described their body image as ‘a little overweight’ or ‘definitely overweight’, and approximately 25.8% of respondents noted that they skipped meals most of the time. Differences between the genders were apparent in several categories. For example, more girls smoked (16.2%) than boys (12.3%), and more males (55.0%) than females (41%) had tried illegal drugs. Participants indicated awareness of other health-compromising behaviours, including unsafe driving habits and high stress levels, and acknowledged several steps they wanted to take to improve their health, as well as the barriers to taking those steps. Students identified improved nutrition, stress reduction, and increased levels of physical activity as particular important health goals. Students also recommended ways in which information and support could be provided within the school environment to enable them to achieve their health-related goals. Several activities developed in collaboration with students have incorporated the recommendations, and have spawned other activities in response to the ongoing identification of new concerns. Conclusions: The process of including the rural community in the identification of health assets and needs from the perspective of students - as well as the planning and implementation of appropriate strategies to address those needs - demonstrates the strengths inherent within a small rural population. Community members’ awareness of the need to create a healthy environment for youth is reflected in their willingness to participate in activities leading to improved health. Greater awareness of the health needs of rural adolescents, and of the influence of gender in some aspects of health behaviors, will help researchers to explore ways in which the unique culture of rural communities can be harnessed to help shape health-focused interventions.Ye

Big Question To Developing Solutions : A Decade of Progress in the Development of Aquatic New Approach Methodologies from 2012 to 2022

In 2012, 20 key questions related to hazard and exposure assessment and environmental and health risks of pharmaceuticals and personal care products in the natural environment were identified. A decade later, this article examines the current level of knowledge around one of the lowest-ranking questions at that time, number 19: "Can nonanimal testing methods be developed that will provide equivalent or better hazard data compared with current in vivo methods?" The inclusion of alternative methods that replace, reduce, or refine animal testing within the regulatory context of risk and hazard assessment of chemicals generally faces many hurdles, although this varies both by organism (human-centric vs. other), sector, and geographical region or country. Focusing on the past 10 years, only works that might reasonably be considered to contribute to advancements in the field of aquatic environmental risk assessment are highlighted. Particular attention is paid to methods of contemporary interest and importance, representing progress in (1) the development of methods which provide equivalent or better data compared with current in vivo methods such as bioaccumulation, (2) weight of evidence, or (3) -omic-based applications. Evolution and convergence of these risk assessment areas offer the basis for fundamental frameshifts in how data are collated and used for the protection of taxa across the breadth of the aquatic environment. Looking to the future, we are at a tipping point, with a need for a global and inclusive approach to establish consensus. Bringing together these methods (both new and old) for regulatory assessment and decision-making will require a concerted effort and orchestration. Environ Toxicol Chem 2023;00:1-15. (c) 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.Peer reviewe

Adolescent health: A rural community's approach

First published in Rural and Remote Health [http://www.rrh.org.au]. Authors of articles published in Rural and Remote Health retain copyright.Introduction: Significant health problems encountered in adulthood often have their roots in health behaviours initiated during adolescence. In order to reverse this trend, school and health personnel, as well as parents and other community members working with high school students, need to be aware of the health-related beliefs and choices that guide the behaviours of teenagers. Although a wide variety of research has been conducted on this topic among urban adolescents, less is known about the health beliefs and behaviors of adolescents residing in rural areas, particularly in Canada. In general, rural Canadians are less healthy than their urban counterparts. Building on the knowledge and understanding of their own community, key stakeholders were invited to engage in the design and implementation of a participatory action research project aimed at understanding and improving the health of rural adolescents. Methods: A group of parents, teachers, students, school administrators and public health nurses engaged in a participatory action research project to better understand determinants of the health of rural adolescents at a high school in Western Canada. Group members developed and administered a health survey to 288 students from a small rural high school, in an effort to identify areas of concern and interest regarding health practices and beliefs of rural adolescents, and to take action on these identified concerns. Results: Results indicated some interesting but potentially worrying trends in this population. For example, while frequent involvement in a physical activity was noted by 75.9% of participants, close to half of the females (48%) described their body image as ‘a little overweight’ or ‘definitely overweight’, and approximately 25.8% of respondents noted that they skipped meals most of the time. Differences between the genders were apparent in several categories. For example, more girls smoked (16.2%) than boys (12.3%), and more males (55.0%) than females (41%) had tried illegal drugs. Participants indicated awareness of other health-compromising behaviours, including unsafe driving habits and high stress levels, and acknowledged several steps they wanted to take to improve their health, as well as the barriers to taking those steps. Students identified improved nutrition, stress reduction, and increased levels of physical activity as particular important health goals. Students also recommended ways in which information and support could be provided within the school environment to enable them to achieve their health-related goals. Several activities developed in collaboration with students have incorporated the recommendations, and have spawned other activities in response to the ongoing identification of new concerns. Conclusions: The process of including the rural community in the identification of health assets and needs from the perspective of students - as well as the planning and implementation of appropriate strategies to address those needs - demonstrates the strengths inherent within a small rural population. Community members’ awareness of the need to create a healthy environment for youth is reflected in their willingness to participate in activities leading to improved health. Greater awareness of the health needs of rural adolescents, and of the influence of gender in some aspects of health behaviors, will help researchers to explore ways in which the unique culture of rural communities can be harnessed to help shape health-focused interventions.Ye

Gesture Production in Language Impairment:It's Quality, Not Quantity, That Matters

PURPOSE: The aim of this study was to determine whether children with language impairment (LI) use gesture to compensate for their language difficulties. Method: The present study investigate d gesture accuracy and frequency i n children with LI (n = 21 ) across gesture imitation, gesture elicitation , spontaneous narrative and interactive problem solving tasks, relative to typically developing (TD) peers (n = 18 ) and peers with low language (LL) and educational concerns (n=21). RESULTS: C hildren with LI showed weaknesses in gesture accuracy (imitation and gesture elicitation ) in comparison to TD peers , but no differences in gesture rate . Children with LL only showed weaknesses in gesture imitation and used significantly more gest ures than TD peers during parent - child interaction. Across the whole sample, motor abilities were significantly related to gesture accuracy but not gesture rate. In addition, children with LI produce d proportionately more extending gestures, suggesting that they may use gesture to replace words that they are unable to articulate verbally. CONCLUSION: The results support the notion that gesture and language form a tightly linked communication system in which gestured eficits are seen alongside difficulties with spoken communication. Furthermore, it is the quality, not quantity of gestures that distinguish children with LI from typical peers