In situ multi-frequency measurements of magnetic susceptibility as an indicator of planetary regolith maturity

Space weathering is now generally accepted to modify the optical and magnetic properties of airless planetary regoliths such as those on the Moon and Mercury. Under micrometeorite and ion bombardment, ferrous iron in such surfaces is reduced to metallic iron spheres, found in amorphous coatings on almost all exposed regolith grains. The size and number distribution of these particles and their location in the regolith all determine the nature and extent of the optical and magnetic changes. These parameters in turn reflect the formation mechanisms, temperatures, and durations involved in the evolution of the regolith. Studying them in situ is of intrinsic value to understanding the weathering process, and useful for determining the maturity of the regolith and providing supporting data for interpreting remotely sensed mineralogy. Fine-grained metallic iron has a number of properties that make it amenable to magnetic techniques, of which magnetic susceptibility is the simplest and most robust. The magnetic properties of the lunar regolith and laboratory regolith analogues are therefore reviewed and the theoretical basis for the frequency dependence of magnetic susceptibility presented. Proposed here is then an instrument concept using multi-frequency measurements of magnetic susceptibility to confirm the presence of fine grained magnetic material and attempt to infer its quantity and size distribution. Such an instrument would be invaluable on a future mission to an asteroid, the Moon, Mercury or other airless rocky Solar System body

The QCD Coupling Constant

This paper presents a summary of the current status of determinations of the strong coupling constant alpha_s. A detailed description of the definition, scale dependence and inherent theoretical ambiguities is given. The various physical processes that can be used to determine alpha_s are reviewed and attention is given to the uncertainties, both theoretical and experimental.Comment: 56 page

Cobalt catalysts for the oxidation of diesel soot particulate

Ceria-supported materials prepared by three routes, coprecipitation from aqueous solution containing both Co2+ and Ce3+ ions, and impregnation of preformed ceria gel with either cobalt(II) nitrate or cobalt(II) acetate, have been investigated for catalytic activity towards oxidation of diesel soot. All three materials catalyze the conversion of diesel soot particulate to carbon dioxide under a flow of either 6 vol.% O2 or 0.5 vol.% NO + 6 vol.% O2 in helium in the temperature range 573?613 K. The temperature of maximum conversion rate shows a small dependence on the particular catalyst and the composition of the oxidant. Raman spectroscopy of the ceria-supported cobalt catalysts indicate that the cobalt is present as Co3O4, but its average particle size in Co/CeO2 impregnated with Co acetate is smaller than the other two Co/CeO2 preparations. Features in the temperature-programmed reduction (TPR) profiles in the range 500?600 K, coincident with the temperature of catalytic activity, appear to be associated with reduction of the cobalt, suggesting a redox-type mechanism assisted by oxygen spillover on the CeO2 support. In contrast, cobalt supported on alumina, silica, and tin(IV) oxide obtained by coprecipitation show much lower activity due to the presence of dispersed Co2+ ions in these materials although small amounts of Co3O4 may be present on alumina and tin(IV) oxide.Fil: Harrison, Philip G.. The University of Nottingham; Reino UnidoFil: Ball, Ian K.. The University of Nottingham; Reino Unido. University Of Nottingham; Reino UnidoFil: Daniell, Wayne. Ludwig Maximilians Universitat; AlemaniaFil: Lukinskas, Povilas. Ludwig Maximilians Universitat; AlemaniaFil: Céspedes, Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: Miro, Eduardo Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; ArgentinaFil: Ulla, Maria Alicia del H.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica ; Argentin

Changes in dietary fiber intake in mice reveal associations between colonic mucin O-glycosylation and specific gut bacteria

The colonic mucus layer, comprised of highly O-glycosylated mucins, is vital to mediating host-gut microbiota interactions, yet the impact of dietary changes on colonic mucin O-glycosylation and its associations with the gut microbiota remains unexplored. Here, we used an array of omics techniques including glycomics to examine the effect of dietary fiber consumption on the gut microbiota, colonic mucin O-glycosylation and host physiology of high-fat diet-fed C57BL/6J mice. The high-fat diet group had significantly impaired glucose tolerance and altered liver proteome, gut microbiota composition, and short-chain fatty acid production compared to normal chow diet group. While dietary fiber inclusion did not reverse all high fat-induced modifications, it resulted in specific changes, including an increase in the relative abundance of bacterial families with known fiber digesters and a higher propionate concentration. Conversely, colonic mucin O-glycosylation remained similar between the normal chow and high-fat diet groups, while dietary fiber intervention resulted in major alterations in O-glycosylation. Correlation network analysis revealed previously undescribed associations between specific bacteria and mucin glycan structures. For example, the relative abundance of the bacterium Parabacteroides distasonis positively correlated with glycan structures containing one terminal fucose and correlated negatively with glycans containing two terminal fucose residues or with both an N-acetylneuraminic acid and a sulfate residue. This is the first comprehensive report of the impact of dietary fiber on the colonic mucin O-glycosylation and associations of these mucosal glycans with specific gut bacteria

Retrieval of the Complete Coding Sequence of the UK-Endemic Tatenale Orthohantavirus Reveals Extensive Strain Variation and Supports Its Classification as a Novel Species

©2020 by the authors. Licensee MDPI, Basel, Switzerland. Orthohantaviruses are globally distributed viruses, associated with rodents and other small mammals. However, data on the circulation of orthohantaviruses within the UK, particularly the UK-endemic Tatenale virus, is sparse. In this study, 531 animals from five rodent species were collected from two locations in northern and central England and screened using a degenerate, pan- orthohantavirus RT-PCR assay. Tatenale virus was detected in a single field vole (Microtus agrestis) from central England and twelve field voles from northern England. Unbiased high-throughput sequencing of the central English strain resulted in the recovery of the complete coding sequence of a novel strain of Tatenale virus, whilst PCR-primer walking of the northern English strain recovered almost complete coding sequence of a previously identified strain. These findings represented the detection of a third lineage of Tatenale virus in the United Kingdom and extended the known geographic distribution of these viruses from northern to central England. Furthermore, the recovery of the complete coding sequence revealed that Tatenale virus was sufficiently related to the recently identified Traemersee virus, to meet the accepted criteria for classification as a single species of orthohantavirus

A T8.5 Brown Dwarf Member of the Xi Ursae Majoris System

The Wide-field Infrared Survey Explorer has revealed a T8.5 brown dwarf (WISE J111838.70+312537.9) that exhibits common proper motion with a solar-neighborhood (8 pc) quadruple star system - Xi Ursae Majoris. The angular separation is 8.5 arc-min, and the projected physical separation is about 4000 AU. The sub-solar metallicity and low chromospheric activity of Xi UMa A argue that the system has an age of at least 2 Gyr. The infrared luminosity and color of the brown dwarf suggests the mass of this companion ranges between 14 and 38 Jupiter masses for system ages of 2 and 8 Gyr respectively.Comment: AJ in press, 12 pages LaTeX with 6 figures. More astrometric data and a laser guide star adaptive optics image adde

Adverse prognostic and predictive significance of low DNA-dependent protein kinase catalytic subunit (DNA-PKcs) expression in early-stage breast cancers

Background: DNA-dependent protein kinase catalytic subunit (DNA-PKcs), a serine threonine kinase belonging to the PIKK family (phosphoinositide 3-kinase-like-family of protein kinase), is a critical component of the non-homologous end joining (NHEJ) pathway required for the repair of DNA double strand breaks. DNA-PKcs may be involved in breast cancer pathogenesis. Methods: We evaluated clinicopathological significance of DNA-PKcs protein expression in 1161 tumours and DNA-PKcs mRNA expression in 1950 tumours. We correlated DNA-PKcs to other markers of aggressive phenotypes, DNA repair, apoptosis and cell cycle regulation. Results: Low DNA-PKcs protein expression was associated with higher tumour grade, higher mitotic index, tumour de-differentiation and tumour type (ps<0.05). Absence of BRCA1, low XRCC1/SMUG1/APE1/Polβ were also more likely in low DNA-PKcs expressing tumours (ps<0.05). Low DNA-PKcs protein expression was significantly associated with worse breast cancer specific survival (BCCS) in univariate and multivariate analysis (ps<0.01). At the mRNA level, low DNA-PKcs was associated with PAM50.Her2 and PAM50.LumA molecular phenotypes (ps<0.01) and poor BCSS. In patients with ER positive tumours who received endocrine therapy, low DNA-PKcs (protein and mRNA) was associated with poor survival. In ER negative patients, low DNA-PKcs mRNA remains significantly associated with adverse outcome. Conclusions: Our study suggests that low DNA-PKcs expression may have prognostic and predictive significance in breast cancers

Governing the governors : a case study of college governance in English further education

This paper addresses the nature of governors in the governance of further education colleges in an English context (1). It explores the complex relationship between governors (people/agency), government (policy/structure) and governance (practice), in a college environment. While recent research has focused on the governance of schooling and higher education there has been little attention paid to the role of governors in the lifelong learning sector. The objective of the paper is to contribute to the debate about the purpose of college governance at a time when the Learning and Skills Council (LSC) commissioning era ends, and new government bodies responsible for further education and training, including local authorities, arrive. The paper analyses the nature of FE governance through the perspectives and experiences of governors, as colleges respond to calls from government for greater improvement and accountability in the sector (LSIS, 2009a). What constitutes creative governance is complex and controversial in the wider framework of regulation and public policy reform (Stoker, 1997; Seddon, 2008). As with other tricky concepts such as leadership, professionalism and learning, college governance is best defined in the contexts, cultures and situations in which it is located. College governance does not operate in a vacuum. It involves governors, chairs, principals, professionals, senior managers, clerks, community, business and wider agencies, including external audit and inspection regimes. Governance also acts as a prism through which national education and training reforms are mediated, at local level. While governing bodies are traditionally associated with the business of FE - steering, setting the tone and style, dealing with finance, funding, audit and procedural matters – they are increasingly being challenged to be more creative and responsive to the wider society. Drawing on a recent case study of six colleges, involving governors and key policy stakeholders, this paper explores FE governance in a fast changing policy environment

Strategic and practical guidelines for successful structured illumination microscopy

Linear 2D- or 3D-structured illumination microscopy (SIM or3D-SIM, respectively) enables multicolor volumetric imaging of fixed and live specimens with subdiffraction resolution in all spatial dimensions. However, the reliance of SIM on algorithmic post-processing renders it particularly sensitive to artifacts that may reduce resolution, compromise data and its interpretations, and drain resources in terms of money and time spent. Here we present a protocol that allows users to generate high-quality SIM data while accounting and correcting for common artifacts. The protocol details preparation of calibration bead slides designed for SIM-based experiments, the acquisition of calibration data, the documentation of typically encountered SIM artifacts and corrective measures that should be taken to reduce them. It also includes a conceptual overview and checklist for experimental design and calibration decisions, and is applicable to any commercially available or custom platform. This protocol, plus accompanying guidelines, allows researchers from students to imaging professionals to create an optimal SIM imaging environment regardless of specimen type or structure of interest. The calibration sample preparation and system calibration protocol can be executed within 1-2 d

Bose-Einstein Correlations of Three Charged Pions in Hadronic Z^0 Decays

Bose-Einstein Correlations (BEC) of three identical charged pions were studied in 4 x 10^6 hadronic Z^0 decays recorded with the OPAL detector at LEP. The genuine three-pion correlations, corrected for the Coulomb effect, were separated from the known two-pion correlations by a new subtraction procedure. A significant genuine three-pion BEC enhancement near threshold was observed having an emitter source radius of r_3 = 0.580 +/- 0.004 (stat.) +/- 0.029 (syst.) fm and a strength of \lambda_3 = 0.504 +/- 0.010 (stat.) +/- 0.041 (syst.). The Coulomb correction was found to increase the \lambda_3 value by \~9% and to reduce r_3 by ~6%. The measured \lambda_3 corresponds to a value of 0.707 +/- 0.014 (stat.) +/- 0.078 (syst.) when one takes into account the three-pion sample purity. A relation between the two-pion and the three-pion source parameters is discussed.Comment: 19 pages, LaTeX, 5 eps figures included, accepted by Eur. Phys. J.