Micro-XRF for In Situ Geological Exploration of Other Planets

In situ analysis of rock chemistry is a fundamental tool for exploration of planets. To meet this need, a high-spatial-resolution micro x-ray fluorescence (Micro-XRF) instrument was developed that is capable of determining the elemental composition of rocks (elements Na U) with 100 microns spatial resolution, thus providing insight to the composition of features as small as sand grains and individual laminae. The resulting excitation beam is of sufficient intensity that high signal-to-noise punctual spectra are acquired in seconds to a few minutes using an Amptek Silicon Drift Detector (SDD). The instrument features a tightly focused x-ray tube and HVPS developed by Moxtek that provides up to 200 micro-A at 10 to 50 keV, with a custom polycapillary optic developed by XOS Inc. and integrated into a breadboard Micro-XRF (see figure). The total mass of the complete breadboard instrument is 2.76 kg, including mounting hardware, mounting plate, camera, laser, etc. A flight version of this instrument would require less than 5W nominal power and 1.5 kg mass. The instrument includes an Amptek SDD that draws 2.5 W and has a resolution of 135 to 155 eV FWHM at 5.9 keV. It weighs 180 g, including the preamplifier, digital pulse processor, multichannel analyzer, detector and preamp power supplies, and packaging. Rock samples are positioned relative to the instrument by a three-axis arm whose position is controlled by closed-loop translators (mimicking the robotic arm of a rover). The distance from the source to the detector is calculated from the position of a focused laser beam on the sample as imaged by the camera. The instrument enables quick scans of major elements in only 1 second, and rapid acquisition (30 s) of data with excellent signal-to-noise and energy resolution for trace element analysi

The Incredible Years® Teacher Classroom Management programme and its impact on teachers' professional self-efficacy, work-related stress, and general well-being: Results from the STARS randomized controlled trial.

BACKGROUND: Teaching is a stressful occupation with poor retention. The Incredible Years® Teacher Classroom Management (TCM) programme is a training programme that research has demonstrated may be an effective intervention for improving children's mental health, but little research has explored any impacts there may be on the teachers' own professional confidence and mental health. AIMS: In this paper, we evaluate whether TCM may lead to changes in teachers' well-being, namely a reduction in burnout and an improvement in self-efficacy and mental health. SAMPLE: Eighty schools across the South West of England were recruited between September 2012 and September 2014. Headteachers were asked to nominate one class teacher to take part. METHODS: Eighty teachers were randomized to either attend a TCM course (intervention) or not (control). TCM was delivered to groups of up to 12 teachers in six whole-day workshops that were evenly spread between October and April. At baseline and 9-month follow-up, we measured teachers' mental health using the Everyday Feelings Questionnaire (EFQ), burnout using the Maslach Burnout Inventory-General Survey (MBI-GS), and self-efficacy using the Teachers' Sense of Efficacy Scale-Short (TSES-Short). RESULTS: Using linear regression models, there was little evidence of differences at follow-up between the intervention and control teachers on the outcomes (the smallest p-value was .09). CONCLUSIONS: Our findings did not replicate previous research that TCM improved teachers' sense of efficacy. However, there were limitations with this study including low sample size

Raman spectroscopy reveals thermal palaeoenvironments of c.3.5 billion-year-old organic matter

Raman spectra of carbonaceous materials in one of the world's oldest sedimentary rock formations – the Strelley Pool Chert (Pilbara Craton, Western Australia) – are analysed to determine whether primary structural characteristics of organic molecules may have survived to the present day. We use Raman spectral parameters to identify variations in molecular structure of the carbon and determine whether original characteristics of the carbonaceous materials have been completely thermally overprinted, as would be expected during c.3.5 billion years of geologic history. To the contrary, we find that the molecular structure of the carbonaceous materials varies depending on the sedimentary layer from which the sample came and the inferred original palaeoenvironmental setting of that layer, as determined by other geochemical and geological data. Thus, we argue that the spectral characteristics of the carbonaceous materials reflect original palaeoenvironments that varied through time from warm hydrothermal settings to cooler marine conditions and a return to hydrothermal conditions. Raman spectroscopy is also used to show that organic matter is present in trace amounts in association with putative stromatolites (laminated sedimentary structures possibly formed by microorganisms) in the Strelley Pool Chert, which were previously thought to be devoid of organic remains. Furthermore, the Raman spectra of carbon associated with stromatolites indicate lower thermal maturity compared to the carbon in (non-stromatolitic) hydrothermal deposits above (younger) and below (older). Significantly, this indicates that the stromatolites are not abiotic hydrothermal precipitates – as previously proposed – but were formed in a cooler marine environment that may have been more favorable to life.8 page(s

Rare earth element geochemistry of carbonaceous black chert of 3.4 Ga Strelley Pool Chert at Mt. Goldsworthy and Mt. Grant, Pilbara Craton: Implications for environment of deposition and habitat of microbes on early Earth

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3.43 billion-year-old stromatolite reef from the Pilbara Craton of western Australia: Ecosystem-scale insights to early life on Earth

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Author Correction: Reassessing evidence of life in 3,700-million-year-old rocks of Greenland

Original article published in Nature, 563(7730), pp. 241-244. In Extended Data Fig. 1 of this Letter, the map showed the field-work location incorrectly; this figure has been corrected online.</p

Characterization of c.3.5 billion-year-old organic matter

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