Analyses of shocked quartz at the global K-P boundary indicate an origin from a single, high-angle, oblique impact at Chicxulub

Accepted versio

Aluminum Foils of the Stardust Interstellar Collector: The Challenge of Recognizing Micrometer-sized Impact Craters made by Interstellar Grains

Preliminary Examination (PE) of the Stardust cometary collector revealed material embedded in aerogel and on aluminium (Al) foil. Large numbers of sub-micrometer impact craters gave size, structural and compositional information. With experience of finding and analyzing the picogram to nanogram mass remains of cometary particles, are we now ready for PE of the Interstellar (IS) collector? Possible interstellar particle (ISP) tracks in the aerogel are being identified by the stardust@home team. We are now assessing challenges facing PE of Al foils from the interstellar collector

Salient practices of award-winning undergraduate research mentors: Balancing freedom and control to achieve excellence

This paper contributes to research on teaching excellence by extending the current body of literature pertaining to mentoring pedagogies in undergraduate research settings across diverse social, institutional and disciplinary contexts. Our data comes from in-depth interviews with 32 international faculty who have received excellence awards for undergraduate research mentoring. The data reveal a freedom - control dialectic, illuminating the ways in which expert mentors negotiate the desire to create opportunities for students to experience freedom and creativity in research, yet maintain control over the topic, quality and outcomes. The research findings reveal a defining characteristic of award-winning mentors as an ability to establish and sustain a sense of challenge, while maintaining meaningful engagement and a sense of achievement amongst students. The findings show the importance of tailoring practice to the needs of particular student groups, and there are implications for institutional resourcing, as well as mentor training and development

Heterogeneity in lunar anorthosite meteorites: Implications for the lunar magma ocean model

The lunar magma ocean model is a well-established theory of the early evolution of the Moon. By this model, the Moon was initially largely molten and the anorthositic crust that now covers much of the lunar surface directly crystallized from this enormous magma source. We are undertaking a study of the geochemical characteristics of anorthosites from lunar meteorites to test this model. Rare earth and other element abundances have been measured in situ in relict anorthosite clasts from two feldspathic lunar meteorites: Dhofar 908 and Dhofar 081. The rare earth elements were present in abundances of approximately 0.1 to approximately 10× chondritic (CI) abundance. Every plagioclase exhibited a positive Eu-anomaly, with Eu abundances of up to approximately 20×CI. Calculations of the melt in equilibrium with anorthite show that it apparently crystallized from a magma that was unfractionated with respect to rare earth elements and ranged in abundance from 8 to 80×CI. Comparisons of our data with other lunar meteorites and Apollo samples suggest that there is notable heterogeneity in the trace element abundances of lunar anorthosites, suggesting these samples did not all crystallize from a common magma source. Compositional and isotopic data from other authors also suggest that lunar anorthosites are chemically heterogeneous and have a wide range of ages. These observations may support other models of crust formation on the Moon or suggest that there are complexities in the lunar magma ocean scenario to allow for multiple generations of anorthosite formation

Making sense of a diagnosis of incurable cancer: The importance of communication

Purpose:  Patients diagnosed with incurable cancer may experience existential distressand difficulty in re-appraising their lives because of uncertainty about the future. Objectives: This study sought to understand how patients living with incurable cancer made sense of their diagnosis, how they prepared for the future and what support they wanted from their health professionals.  Subjects:  27 patients were recruited from the oncology and palliative care service at three metropolitan hospitals. Methods:  A qualitative research approach was used. Semi-structured face-to-face interviews were conducted. Interviews were audio-taped and transcribed verbatim.  Data was analyzed using the constant-comparative method.  Results:  Participants did not express a need to make sense of their diagnosis nor always ascribe to a particular religious belief; rather, many relied on a personal spirituality or philosophy to bring meaning to their experience. Importance was placed on their doctor keeping up with technology, being honest, and being confident and positive. Conclusion:  Participants in this study had incurable cancer but making sense of their current situation was not a conscious priority. For these patients, uncertainty was a positive, as certainty for them indicates death is approaching. What these interviews suggest, from the patient’s perspective, is that there is an implied contract between doctor and patient during this period which involves the doctor managing the flow of difficult information so that the patient can maintain normality for as long as possible. Understanding this helps to explain the difficulty of having advance care planning conversations within this setting, despite the many opportunities that a longer disease trajectory would seem to offer.

Rapid Quantification of Molecular Diversity for Selective Database Acquisition

There is an increasing need to expand the structural diversity of the molecules investigated in lead-discovery programs. One way in which this can be achieved is by acquiring external datasets that will enhance an existing database. This paper describes a rapid procedure for the selection of external datasets using a measure of structural diversity that is calculated from sums of pairwise intermolecular structural similarities

Continuing specialist care into adulthood in young people with juvenile idiopathic arthritis: a retrospective cohort study using electronic health records in England.

OBJECTIVES: This study aimed to measure (1) the proportion of children who continue to receive specialist care (rheumatology/ophthalmology) as adults, (2) the characteristics associated with continuing specialist care, and (3) the frequency of specialist care appointments in both paediatric and adult services. METHODS: A retrospective cohort of young people with JIA was identified from UK primary care electronic health records (Clinical Practice Research Datalink) between 1 April 2003 and 31 December 2018. To be included in the study, cases needed to have at least 1 year of registration at their general practice beyond age 18 and linkage to Hospital Episodes Statistics data for secondary care information. All specialist care outpatient visits were identified from Hospital Episodes Statistics outpatient data. RESULTS: There were 666 young people included in the study. Of these, 427 (64%) received specialist care beyond age 18, 90 (13%) had their last recorded contact at 16-17 years and 149 (22%) did not continue after 16 years. Older age at diagnosis, female gender, less deprivation and a childhood diagnosis of uveitis were associated with continuing specialist care beyond age 18. Of those continuing beyond 18, 35% (n = 153) were subsequently discharged by the study end date. Of all those discharged, 32% had a missed appointment recorded after the last attended visit, suggesting failure to attend. CONCLUSIONS: Two-thirds of young people with JIA continue to receive specialist care beyond age 18. This is useful information for children and young people with JIA and their families planning for their future, and for clinicians planning health-care services

Analysis of Cometary Dust Impact Residues in the Aluminum Foil Craters of Stardust

In January 2006, the sample return capsule from NASA s Stardust spacecraft successfully returned to Earth after its seven year mission to comet Wild-2. While the principal capture medium for comet dust was low-density graded silica aerogel, the 1100 series aluminum foil (approximately 100 m thick) which wrapped around the T6064 aluminum frame of the sample tray assembly (STA) contains micro-craters that constitute an additional repository for Wild-2 dust. Previous studies of similar craters on spacecraft surfaces, e.g. the Long Duration Exposure Facility (LDEF), have shown that impactor material can be preserved for elemental and mineralogical characterization, although the quantity of impact residue in Stardust craters far exceeds previous missions. The degree of shock-induced alteration experienced by the Wild-2 particles impacting on foil will generally be greater than for those captured in the low-density aerogel. However, even some of the residues found in LDEF craters showed not only survival of crystalline silicates but even their solar flare tracks, which are extremely fragile structures and anneal at around 600 C. Laboratory hypervelocity experiments, using analogues of Wild-2 particles accelerated into flight-grade foils under conditions close to those of the actual encounter, showed retention of abundant projectile residues at the Stardust encounter velocity of 6.1 km/s. During the preliminary examination (PE) of the returned foils, using optical and electron microscopy studies, a diverse range in size and morphologies of micro-craters was identified. In this abstract we consider the state of residue preservation in a diverse range of craters with respect to their elemental composition and inferred mineralogy of the original projectiles