Stable isotopic studies of H,C,N,O and S in samples of Martian origin

The present day geochemical cycles of volatile elements through the various reservoirs on Earth are largely understood within the context of the planet's standing as a geologically and biologically evolved body. In terrestrial studies stable isotope measurements of light elements (H, C, N, O and S) can be utilized to obtain insight into the conditions prevailing during formation of rocks of various types. Perhaps the most important problem which could be addressed by light element studies of the sorts of specimen likely to be available from remote automatic sampling, would be the role of volatiles during evolution. Of fundamental importance here is the question of whether Mars was volatile rich or volatile poor. The only way to fully comprehend the effects of volatile cycling through the mantle crust and regolith atmosphere polar cap system of Mars, is by analyses of appropriate returned samples. In order to interpret the record of geological activity in Martian samples it will be necessary to understand how the past, or present, surface environment may have acted to disturb the primary characteristics of the rocks

Lunar nitrogen: Secular variation or mixing?

The two current models to explain the nearly 40% variation of the lunar nitrogen isotopic composition are: (1) secular variation of solar wind nitrogen; and (2) a two component mixing model having a constant, heavy solar wind admixed with varying amounts of indigenous light lunar N (LLN). Both models are needed to explain the step pyrolysis extraction profile. The secular variation model proposes that the low temperature release is modern day solar wind implanted into grain surfaces, the 900 C to 1100 C release is from grain surfaces which were once exposed to the ancient solar wind but which are now trapped inside agglutinates, and the >1100 C release as spallogenic N produced by cosmic rays. The mixing model ascribes the components to solar wind, indigenous lunar N and spallogenic N respectively. An extension of either interpretation is that the light N seen in lunar breccias or deep drill cores represent conditions when more N-14 was available to the lunar surface

The story so far: A systematic review of the dialogic reading literature

Background: Dialogic reading (DR; Whitehurst et al., 1988) is an evidence-based intervention that promotes children's active participation in shared reading (Towson, 2016; Urbani, 2020; WWC, 2007, 2010). Since the development of DR, there has been a proliferation of studies evaluating the conditions and populations with which it is effective. However, to date, there has not been a systematic review of the literature focusing specifically on the impact of DR on the literacy and non-literacy skills of children under 10 years old. As DR research evolves, it is important that a review of the existing literature is undertaken to capture these advances and guide future research. / Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol, the aim of this review is to systematically explore, synthesise and critically evaluate the extant literature. A systematic search of electronic databases identified 46 relevant studies, and the overall methodological quality of the studies was assessed using the MMAT. / Results: Findings are organised according to sample and population, country of origin and setting, programme duration, language and literacy outcomes, social-emotional and other cognitive outcomes, impact and effect sizes to provide overview and insight into where and with whom DR is most effective. / Conclusions: The review findings suggest DR can positively impact a wide range of language and literacy skills for children under 5 years. There is some evidence that DR can have positive effects on enjoyment of reading, reading motivation, parental–child attachment, parental confidence and stress. However, the extant research is subject to limitations, and more methodologically robust research is needed to enable thorough assessment of the conditions in which DR is most effective

New data on carbon isotopic compositions of some ureilites

We have collected new C data from high resolution stepped combustion analyses of 5 ureilites to better constrain their relationships with O and mineralogical/petrographic groupings. This may help the future development of petrogenetic models

The Distribution of Ar and Xe Inside Diamond Grains from Efremovka

Analysis of the release pattern of Ar and Xe from grain size fractions of Efremovka presolar diamonds at stepped combustion and pyrolysis indicates that in both cases the gases release as a result of destruction of the diamond lattice

The Holbrook Meteorite - 99 Years Out in the Weather

At 7:15pm on the evening of 19th July 1912, a bright fireball appeared in the sky above Navajo County, Arizona [1]. After several loud detonations, approximately 16,000 mostly pea-sized stones fell near the Arntz siding of the Santa Fe Railroad, 7 miles from the town of Holbrook. A search orchestrated by W.M.Foote resulted in nearly 220 kg of material being recovered; samples were exchanged with a great many of the World's Museums [2]. In 1931 Harvey Nininger revisited the site and was able to find another 23 kg that had originally been missed [3]. One of us (EKG) returned again in 1968 and found a further ca 1.5 kg specimen [4]. Meteorite hunters have been going back to Holbrook ever since in the hope of more finds. For example in 2001 a group of 45 searchers accumulated 440 g of previously overlooked L6 group meteorite fragments. In 2011, the 99th anniversary of the event, Rubin Garcia located 11 mini-meteorites [5]