Oxygen production from dissociation of Europa's water-ice surface.

Jupiter's moon Europa has a predominantly water-ice surface that is modified by exposure to its space environment. Charged particles break molecular bonds in surface ice, thus dissociating the water to ultimately produce H2 and O2, which provides a potential oxygenation mechanism for Europa's subsurface ocean. These species are understood to form Europa's primary atmospheric constituents. Although remote observations provide important global constraints on Europa's atmosphere, the molecular O2 abundance has been inferred from atomic O emissions. Europa's atmospheric composition had never been directly sampled and model-derived oxygen production estimates ranged over several orders of magnitude. Here, we report direct observations of H2+ and O2+ pickup ions from the dissociation of Europa's water-ice surface and confirm these species are primary atmospheric constituents. In contrast to expectations, we find the H2 neutral atmosphere is dominated by a non-thermal, escaping population. We find 12 ± 6 kg s-1 (2.2 ± 1.2 × 1026 s-1) O2 are produced within Europa's surface, less than previously thought, with a narrower range to support habitability in Europa's ocean. This process is found to be Europa's dominant exogenic surface erosion mechanism over meteoroid bombardment.

In Science Journals.

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In Science Journals.

Highlights from the Science family of journals.

In Science Journals.

Highlights from the Science family of journals.

In Science Journals.

Highlights from the Science family of journals.

In Science Journals.

Highlights from the Science family of journals.

In Science Journals.

Highlights from the Science family of journals.

In Science Journals.

Highlights from the Science family of journals.

In Science Journals.

Highlights from the Science family of journals.

In Science Journals.

Highlights from the Science family of journals.

Fabrication, defect chemistry and microstructure of Mn-doped UO2.

Mn-doped UO2 is under consideration for use as an accident tolerant nuclear fuel. We detail the synthesis of Mn-doped UO2 prepared via a wet co-precipitation method, which was refined to improve the yield of incorporated Mn. To verify the Mn-doped UO2 defect chemistry, X-ray absorption spectroscopy at the Mn K-edge was performed, in addition to X-ray diffraction, Raman spectroscopy and high-energy resolved fluorescence detection X-ray absorption near edge spectroscopy at the U M4-edge. It was established that Mn2+ directly substitutes for U4+ in the UO2 lattice, accompanied by oxygen vacancy (Ov) charge compensation. In contrast to other divalent-element doped UO2 materials, compelling evidence for U5+ in a charge compensating role was not found. This work furthers understanding of the structure and crystal chemistry of Mn-doped UO2, which could show potential advantages as a novel efficient advanced nuclear fuel.

In Science Journals.

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Ethnic differences in treatment outcome for children and young people accessing mental health support.

Children and Young People (CYP) from minoritized ethnic backgrounds experience structural inequalities in Children and Young People's Mental Health Settings (CYPMHS). This mixed methods study explores whether CYP's ethnicity is associated with their treatment outcomes (operationalised as 'measurable change') from CYPMHS. A multilevel multi-nominal regression analysis, controlling for age, gender, referral source, presenting difficulty, case closure reason, suggests that CYP from Asian backgrounds (OR = 0.82, CI [0.70, 0.96]) and Mixed-race (odds ratio (OR) = 0.80; 95% CI [0.69, 0.92]) are less likely to report measurable improvement in mental health difficulties compared to White British CYP. Three themes from a thematic analysis of semi-structured interviews with 15 CYP from minoritized ethnic backgrounds focused on views and experiences of ending mental health support are also presented. CYP view personalised support and the right therapist as conducive to good endings and valued a range of outcomes pertaining to empowerment. Experiences of stigma and inequalities may begin to explain the less positive outcomes experienced by Asian and Mixed-race CYP found in the regression analysis. The implications of these findings and future areas of research are suggested.

Impaired communication ability in SOX11 syndrome.

BACKGROUND: Speech and language skills are important for social interaction and learning. This study characterised the communication abilities of verbal individuals with SOX11 syndrome using a standardised parent/carer questionnaire, the Children's Communication Checklist (CCC-2). METHOD: Thirteen parent/carers of verbal individuals (aged 5-19 years) diagnosed with SOX11 syndrome completed the CCC-2. In order to contextualise findings, responses were compared to norms and to data from Noonan syndrome, a relatively well-known genetic diagnosis associated with communication impairment. RESULTS: For all individuals, the CCC-2 composite score indicated significant communication difficulties. Language structure (speech, syntax, semantics and coherence), pragmatic language (inappropriate initiation, stereotyped language use of context and non-verbal communication) and autistic features (social relations and interests) scores were lower than typically developing norms. Subscale comparisons revealed relative difference in use of context compared to other pragmatic domains (stereotyped language and inappropriate initiation). Individual scores showed substantial variation, particularly in regard to language structure profile. Differences were more pronounced than for Noonan syndrome, specifically in domains of speech, syntax, non-verbal communication and social relations. CONCLUSIONS: SOX11 syndrome is associated with communication impairment. It is important to assess communication abilities as part of the management of individuals with SOX11 syndrome and understand individual strengths and difficulties in order to provide targeted support.

Diamond-Like Carbon: A Surface for Extreme, High-Wear Environments.

In this study, we present an in-depth characterization of a diamond-like carbon (DLC) film, using a range of techniques to understand the structure and chemistry of the film both in the interior and particularly at the DLC/air surface and DLC/liquid interface. The DLC film is found to be a combination of sp2 and sp3 carbon, with significant oxygen present at the surface. The oxygen seems to be present as OH groups, making the DLC somewhat hydrophilic. Quartz-Crystal Microbalance (QCM) isotherms and complementary neutron reflectivity data indicate significant adsorption of a model additive, bis(2-ethylhexyl) sulfosuccinate sodium salt (AOT) surfactant, onto the DLC from water solutions and indicate the adsorbed film is a bilayer. This initial study of the structure and composition of a model surfactant is intended to give a clearer insight into how DLC and additives function as antiwear systems.

In Science Journals.

Highlights from the Science family of journals.

In Science Journals.

Highlights from the Science family of journals.

In Science Journals.

Highlights from the Science family of journals.

In Science Journals.

Highlights from the Science family of journals.

In Science Journals.

Highlights from the Science family of journals.