Developing atom probe tomography of phyllosilicates in preparation for extra-terrestrial sample return

Hydrous phyllosilicate minerals, including the serpentine subgroup, are likely to be major constituents of material that will be bought back to Earth by missions to Mars and to primitive asteroids Ryugu and Bennu. Small quantities (< 60 g) of micrometre sized, internally heterogeneous material will be available for study, requiring minimally destructive techniques. Many conventional methods are unsuitable for phyllosilicates as they are typically finely crystalline and electron beam sensitive resulting in amorphisation and dehydration. New tools will be required for nanoscale characterisation of these precious extra‐terrestrial samples. Here we test the effectiveness of atom probe tomography (APT) for this purpose. Using lizardite from the Ronda peridotite, Spain, as a terrestrial analogue, we outline an effective analytical protocol to extract nanoscale chemical and structural measurements of phyllosilicates. The potential of APT is demonstrated by the unexpected finding that the Ronda lizardite contains SiO‐rich nanophases, consistent with opaline silica that formed as a by‐product of the serpentinisation of olivine. Our new APT approach unlocks previously unobservable nanominerals and nanostructures within phyllosilicates owing to resolution limitations of more established imaging techniques. APT will provide unique insights into the processes and products of water/rock interaction on Earth, Mars and primitive asteroids

Adolescent growth and pubertal progression in the Silver-Russell syndrome.

The pattern of growth and development of 18 adolescent children with the Silver-Russell syndrome was studied. Mature height was about -3.6 standard deviation scores in both sexes. This is comparable to the height reduction at diagnosis, which has been reported previously. The pattern of puberty and adolescent growth was essentially normal and occurred at a marginally earlier time than normal, although in this small series the differences were not significant. In the girls there was a tendency to gain subcutaneous fat after puberty. This trend was not apparent in the boys

A matter of stability and equity: the case for federal action on renewable portfolio standards in the U.S

Renewable portfolio standards (RPS) are a relatively novel way to promote renewable energy projects in the United States. Though more than half the states and the District of Columbia have taken the lead in mandating some form of RPS, none of the existing state programs are alike. The author proposes federal action to fix many of the problems plaguing individual state RPS programs and to persuade national policymakers, industries, and consumers to make a long-term commitment to renewable energy. If implemented properly, a nation-wide RPS could lower electricity rates for many consumers and utilities and may even induce more diversification in the electric utility industry