New nonrenormalization theorems for anomalous three point functions

Nonrenormalization theorems involving the transverse, i.e. non anomalous, part of the correlator in perturbative QCD are proven. Some of their consequences and questions they raise are discussed.Comment: 14 pages. People added in the acknowledgements. Minor changes to match version to appear in journa

A Conspicuous Clay Ovoid in Nakhla: Evidence for Subsurface Hydrothermal Alteration on Mars with Implications for Astrobiology

A conspicuous biomorphic ovoid structure has been discovered in the Nakhla martian meteorite, made of nanocrystalline iron-rich saponitic clay and amorphous material. The ovoid is indigenous to Nakhla and occurs within a late-formed amorphous mesostasis region of rhyolitic composition that is interstitial to two clinopyroxene grains with Al-rich rims, and contains acicular apatite crystals, olivine, sulfides, Ti-rich magnetite, and a new mineral of the rhoenite group. To infer the origin of the ovoid, a large set of analytical tools was employed, including scanning electron microscopy and backscattered electron imaging, wavelength-dispersive X-ray analysis, X-ray mapping, Raman spectroscopy, time-of-flight secondary ion mass spectrometry analysis, high-resolution transmission electron microscope imaging, and atomic force microscope topographic mapping. The concentric wall of the ovoid surrounds an originally hollow volume and exhibits internal layering of contrasting nanotextures but uniform chemical composition, and likely inherited its overall shape from a preexisting vesicle in the mesostasis glass. A final fibrous layer of Fe-rich phases blankets the interior surfaces of the ovoid wall structure. There is evidence that the parent rock of Nakhla has undergone a shock event from a nearby bolide impact that melted the rims of pyroxene and the interstitial matter and initiated an igneous hydrothermal system of rapidly cooling fluids, which were progressively mixed with fluids from the melted permafrost. Sharp temperature gradients were responsible for the crystallization of Al-rich clinopyroxene rims, rhoenite, acicular apatites, and the quenching of the mesostasis glass and the vesicle. During the formation of the ovoid structure, episodic fluid infiltration events resulted in the precipitation of saponite rinds around the vesicle walls, altered pyrrhotite to marcasite, and then isolated the ovoid wall structure from the rest of the system by depositing a layer of iron oxides/hydroxides. Carbonates, halite, and sulfates were deposited last within interstitial spaces and along fractures. Among three plausible competing hypotheses here, this particular abiotic scenario is considered to be the most reasonable explanation for the formation of the ovoid structure in Nakhla, and although compelling evidence for a biotic origin is lacking, it is evident that the martian subsurface contains niche environments where life could develop. © Mary Ann Liebert, Inc

Anecdotal to actual: identifying users of learning development to inform future practice

With increasing pressure on universities to ensure their students are graduating with a good honours degree, understanding where Learning Development sits in the university and its impact is arguably becoming more important. The Centre for Learning and Study Support (CLaSS) at De Montfort University, Leicester, has investigated data, collected since 2010, on student engagement with our Learning Development Service. The study aimed to discover the diversity of students availing of learning development, with regards to characteristics such as: gender, ethnicity, disability, age, parental education and module marks. The data presented shows how CLaSS can justifiably engage in university wide discussions about retention and achievement, as well as widening participation agendas. It compares, where possible, who is using CLaSS to the diversity of students within the university. Initial findings are presented, with discussion about how findings have impacted practice, with a particular focus on the attainment gap. From close analysis of the findings which demonstrate a lack of engagement by males with learning development, the paper proposes why this may be the case and offers insight into recent activities to try and reduce the gender gap. Overall, the paper recognises how interpretation of and greater awareness of our user diversity has informed our team strategy and future direction

Curiosity at Gale Crater, Mars: Characterization and analysis of the rocknest sand shadow

The Rocknest aeolian deposit is similar to aeolian features analyzed by the Mars Exploration Rovers (MERs) Spirit and Opportunity. The fraction of sand <150 micrometers in size contains ~55% crystalline material consistent with a basaltic heritage and ~45% x-ray amorphous material. The amorphous component of Rocknest is iron-rich and silicon-poor and is the host of the volatiles (water, oxygen, sulfur dioxide, carbon dioxide, and chlorine) detected by the Sample Analysis at Mars instrument and of the fine-grained nanophase oxide component first described from basaltic soils analyzed by MERs. The similarity between soils and aeolian materials analyzed at Gusev Crater, Meridiani Planum, and Gale Crater implies locally sourced, globally similar basaltic materials or globally and regionally sourced basaltic components deposited locally at all three locations