515 research outputs found

    Lunar Crustal History from Isotopic Studies of Lunar Anorthosites

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    Anorthosites occur ubiquitously within the lunar crust at depths of approx.3-30 km in apparent confirmation of the Lunar Magma Ocean (LMO) hypothesis. [1]. We will present recent chronological studies of anorthosites [2] that are relevant both to the LMO hypothesis and also to the lunar cataclysm hypothesis. Old (approx.4.4 Ga) Sm-Nd ages have been determined for some Apollo 16 anorthosites, and primitive initial Sr-87/Sr-86 ratios have been measured for several, but well-defined Rb-Sr ages concordant with the Sm-Nd ages have not been determined until now. Lunar anorthosite 67075, a Feldspathic Fragmental Breccia (FFB) collected near the rim of North Ray Crater, has concordant Sm-Nd and Rb-Sr ages of 4.47+/-0.07 Ga and 4.49+/-0.07 Ga, respectively. Initial Nd-143/Nd-144 determined from the Sm-Nd isochron corresponds to E(sub Nd,CHUR) = 0.3+/-0.5 compared to a Chondritic Uniform Reservoir, or E(sub Nd,HEDPB) = -0.6+/-0.5 compared to the initial Nd-143/Nd-144 of the HED Parent Body [3]. Lunar anorthosites tend to have E(sub Nd) > 0 when compared to CHUR, apparently inconsistent with derivation from a single lunar magma ocean. Although E(sub Nd) < 0 for some anorthosites, if lunar initial Nd-143/Nd-144 is taken equal to HEDR for the HED parent body [3], enough variability remains among the anorthosite data alone to suggest that lunar anorthosites do not derive from a single source, i.e., they are not all products of the LMO. An anorthositic clast from desert meteorite Dhofar 908 has an Ar-39-Ar-40 age of 4.42+/-0.04 Ga, the same as the 4.36-4.41+/-0.035 Ga Ar-39-Ar-40 age of anorthositic clast Y-86032,116 in Antarctic meteorite Yamato- 86032 [3,4]. Conclusions: (i) Lunar anorthosites come from diverse sources. Orbital geochemical studies confirm variability in lunar crustal composition [1, 5]. We suggest that the variability extends to anorthosites alone as shown by the Sm-Nd data (Fig. 2) and the existence of magnesian anorthosites (MAN, [6]) and "An93 anorthosites" [3,4]. (ii) Anorthositic clasts in lunar meteorites retain "high" Ar-Ar ages compared to Apollo anorthosites. This is perhaps a hint that "cataclysmic" impacts were on average less energetic in the mostly farside source regions of these meteorites than on the lunar nearside

    In the picture: Representations of librarianship in children's picture books published in the UK between 1994-2014

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    The aim of this study is to enhance understanding of how librarians are perceived by UK society, with the intention that such knowledge be used in campaigns to enhance their image, and thereby encourage more young people to enter the profession. The following three objectives are utilised to accomplish this aim: 1. the literature review covers a range of sectors to produce a broad understanding of how children’s books reflect social ideologies 2. depictions of librarians and libraries in children’s picture books are analysed, contributing a unique perspective to existing library research 3. portrayals are discussed in terms of their accuracy and ideological attitude, with changes mapped over time. Representations of libraries and librarians have been gathered from both the narratives and illustrations in a set of eight children’s picture books published in the UK between 1994 and 2014, using a custom data-gathering framework. This involves hermeneutics, semiotics and a ‘positive, neutral or negative’ ideology. Key data has then been transferred to a coding device to enable comparative analysis and compilation of overviews. The thesis has found that depictions of libraries and librarians have been more favourable in the present century than they were in the last. Even when aspects of the stereotype were detected, they did not produce a negative view of the profession, and no correlation was found between stereotyping and the overall view of librarians. However, the interaction of the librarian with their patrons made a significant impact on overall ratings. The textual analysis corroborated literature review findings of a lack in differentiation between professional and para-professional staff, which may be causing misunderstanding of the level of skills and knowledge that librarians possess. Comprehension of our value to society is therefore deficient and must be urgently addressed if we are to entice more young professionals

    ChiPrints quick guide

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    A quick guide to the University of Chichester's research repository including: what the repository is, where the repository can be accessed, why researchers should deposit, a simple guide to depositing, and information on how to get help if necessary

    Basaltic Clasts in Y-86032 Feldspathic Lunar Meteorite: Ancient Volcanism far from the Procellarum Kreep Terrane

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    Lunar meteorite, Y-86032 is a fragmental or regolith breccia enriched in Al2O3 (28-31 wt%) and having very low concentrations of REEs and Th, U [e.g., 1]. Nyquist et al. [2] suggested that Y- 86032 contains a variety of lithologies not represented by the Apollo samples. They found clasts with old Ar-Ar ages and an ancient Sm-Nd age, and negative Nd indicating a direct link to the primordial magma ocean. Importantly, the final lithification of the Y-86032 breccia was likely >3.8-4.1 Ga ago. Therefore, any lithic components in the breccia formed prior to 3.8 Ga, and lithic components in breccia clasts in the parent breccia formed even earlier. Here we report textures and mineralogy of basaltic and gabbroic clasts in Y- 86032 to better understand the nature of ancient lunar volcanism far from the Procellarum KREEP Terrain (PKT) [3] and the central nearside

    Will fish be part of future healthy and sustainable diets?

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    First paragraph: The adoption of healthy and sustainable diets and food systems is recognised as a means to address the global challenge of malnutrition and poor-quality diets, and unprecedented environmental damage from food production and consumption.1 Sustainable diets have also been recognised as a key strategy to achieve the Sustainable Development Goals. Reducing consumption of animal-source foods is frequently presented as key to improving the sustainability of food systems.2 Fish and seafood can have a lower environmental impact and in many cases are considered more efficient than terrestrial animal production (albeit with wide variation) depending on the type of production or capture method,3 yet remain largely absent, or insufficiently articulated in the sustainable diets literature, rendering their future role in healthy diets unclear.4 This absence of specific consideration of fish and seafood extends to food security literature, in which the role of fish remains under-recognised and undervalued.5 Legitimate concerns exist regarding the environmental sustainability of fisheries and aquaculture systems; however, we argue that an overemphasis on the so-called doomsday portrayal of fish—which often dominates literature and the broader media—masks the myriad of positive contributions of the fisheries sector to nutrition and sustainability and limits its scope in contributing to healthy and sustainable food systems

    Oligodendrocyte RasG12V Expressed in its Endogenous Locus Disrupts Myelin Structure Through Increased MAPK, Nitric Oxide, and Notch Signaling

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    Costello syndrome (CS) is a gain of function Rasopathy caused by heterozygous activating mutations in the HRAS gene. Patients show brain dysfunction that can include abnormal brain white matter. Transgenic activation of HRas in the entire mouse oligodendrocyte lineage resulted in myelin defects and behavioral abnormalities, suggesting roles for disrupted myelin in CS brain dysfunction. Here we studied a mouse model in which the endogenous HRas gene is conditionally replaced by mutant HRasG12V in mature oligodendrocytes, to separate effects in mature myelinating cells from developmental events. Increased myelin thickness due to decompaction was detectable within one month of HRasG12V expression in the corpus callosum of adult mice. Increases in active ERK and Nitric Oxide (NO) were present in HRas mutants and inhibition of NO synthase (NOS) or MEK each partially rescued myelin decompaction. In addition, genetic or pharmacologic inhibition of Notch signaling improved myelin compaction. Complete rescue of myelin structure required dual drug treatments combining MAPK, NO or Notch inhibition; with MEK + NOS blockade producing the most robust effect. We suggest that individual or concomitant blockade of these pathways in Costello syndrome patients may improve aspects of brain function

    Lunar Crustal History Recorded in Lunar Anorthosites

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    Anorthosites occur ubiquitously within the lunar crust at depths of ~3-30 km in apparent confirmation of the Lunar Magma Ocean (LMO) hypothesis. We have dated lunar anorthosite 67075, a Feldspathic Fragmental Breccia (FFB) collected near the rim of North Ray Crater by the Sm-Nd and Rb-Sr techniques. We also have dated an anorthositic white clast (WC) in lunar meteorite Dhofar 908 by the Ar-39-Ar-40 technique and measured whole rock (WR) Sm-Nd data for a companion sample. We discuss the significance of the ages determined for these and other anorthosites for the early magmatic and bombardment history of the moon
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