498 research outputs found

    Lunar sample analysis

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    The surface composition of two samples from the highly shocked, glass-coated lunar basalt (12054) and from four glass-coated fragments from the 1-2 mm (14161) fines were examined by X-ray photoemission spectroscopy to determine whether the agglutination process itself is responsible for the difference between their surface and bulk compositions. Auger electron spectroscopy of glass balls from the 15425 and 74001 fines were analyzed to understand the nature, extent, and behavior of volatile phases associated with lunar volcanism. Initial results indicate that (1) volatiles, in the outer few atomic layers sampled, vary considerably from ball to ball; (2) variability over the surface of individual balls is smaller; (3) the dominant volatiles on the balls are S and Zn; and (4) other volatiles commonly observed are P, Cl, and K

    Membership categorization, culture and norms in action

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    In this article, we examine the extent to which membership categorization analysis (MCA) can inform an understanding of reasoning within the public domain where morality, policy and cultural politics are visible (Smith and Tatalovich, 2003). Through the examination of three examples, we demonstrate how specific types of category device(s) are a ubiquitous feature of accountable practice in the public domain where morality matters and public policy intersect. Furthermore, we argue that MCA provides a method for analysing the mundane mechanics associated with everyday cultural politics and democratic accountability assembled and presented within news media and broadcast settings

    A study of cyber hate on Twitter with implications for social media governance strategies

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    This paper explores ways in which the harmful effects of cyber hate may be mitigated through mechanisms for enhancing the self-governance of new digital spaces. We report findings from a mixed methods study of responses to cyber hate posts, which aimed to: (i) understand how people interact in this context by undertaking qualitative interaction analysis and developing a statistical model to explain the volume of responses to cyber hate posted to Twitter, and (ii) explore use of machine learning techniques to assist in identifying cyber hate counter-speech

    Ionizing beam-induced adhesion enhancement and interface chemistry for Au-GaAs

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    MeV ion beam-induced adhesion enhancement of Au-films (∼500 Å thick) on p-type and n-type GaAs substrates has been studied by the scratch test, ESCA, and nuclear reaction hydrogen profiling. For films resistively deposited in a diffusion pumped chamber at 2−5×10^(−6)torr, the data indicate that the adhesion enhancement is associated with oxide layers on the substrate surface adsorbed before the film deposition. The ESCA data suggest that water vapour dissociates and forms Ga(OH)_3 at the interface layers under ionizing radiation. The oxide concentration at the interface varies with substrate electronic properties and gives a large difference in the adhesion enhancement. However, the data obtained so far on the hydrogen concentration at the interface indicate that within our range of sensitivity it is about the same for substrates with different electronic properties. Our data demonstrate the importance of a thin absorbed (impurity) layer for the interface chemistry and adhesion enhancement by ionizing radiation

    Appreciating cultural diversity through clinical supervision

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    Abstract: Structured supervision techniques encourage service providers to increase their knowledge, skills, and selfawareness in providing multicultural services. Structured techniques are described and illustrated

    Calling time on Oronsay: revising settlement models around the mesolithic–neolithic transition in Western Scotland, new evidence from Port Lobh, Colonsay

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    For over 120 years, the shell middens of western Scotland and the series of open-air sites on Oronsay have been the focus of debate in European Mesolithic studies. This paper challenges the significance of Oronsay in light of results from the geophysical survey and test-excavation of a new limpet and periwinkle shell midden dated to the late 5th or start of the 4th millennium cal BC at Port Lobh, Colonsay that offers fresh evidence to re-evaluate critically the role of Oronsay and coastal resources in island settlement models ahead of the Mesolithic–Neolithic transition. Test excavations recovered a marine molluscan assemblage dominated by limpet and periwinkle shells together with crab, sea urchin, a fishbone assemblage composed mainly of Gadidae, some identifiable bird and mammal bone, carbonised macroplant remains, and pumice as well as a bipolar lithic assemblage and coarse stone implements. Novel seasonality studies of saithe otolith thin-sections suggest wintertime tidal fishing practices. At least two activity events may be discerned, dating from the late 5th millennium cal BC. The midden could represent a small number of rapidly deposited assemblages or maybe the result of stocastic events within a more extended timeframe. We argue that alternative research questions are needed to advance long-standing debates about seasonal inter island mobility versus island sedentism that look beyond Oronsay to better understand later Mesolithic occupation patterns and the formation and date of Oronsay middens. We propose alternative methodological strategies to aid identification of contemporaneous sites using geophysical techniques and lithic technological signatures

    Chapter 2 - Luminescence analysis (OSL and TL) from Karabai I

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    This chapter reports a pilot study by two luminescence laboratories on samples from the 2004 excavations of Karabai I. The Scottish Universities Environmental Research Centre (SUERC) examined the optical stimulated luminescent (OSL) properties of the sediments using a method called luminescence profiling (Burbidge et al. 2007); the Max-Planck-Institute for Evolutionary Anthropology, Leipzig attempted to analyse the thermoluminescence (TL) age of a small collection of heated stones. Luminescence profiling is a rapid survey method for assessing the suitability of sediments for full dating based on the presence of particular minerals, grain-sizes and luminescence signals. At Karabai I the study revealed many factors that would complicate a subsequent full dating study, however a tentative age range of 60-115 ka was obtained using the ‘IRSL’ and ‘post IR & OSL TL’ signal from the polymineral coarse fraction. Luminescence signals based on quartz were found to be saturating and so could provide only minimum ages. Only one heated rock of sufficient mass, recovered in square 4H archaeological layer 2, exhibited acceptable properties for successful dating. The resulting TL age, 142 ± 23 ka (EVA-LUM-06/01), places Karabai I within MIS 6. This contrasts with the luminescence profile study that suggested sedimentary deposition within MIS 4-5. In both studies it is important to recognise the tentative nature of these conclusions

    Using venous blood gas analysis in the assessment of COPD exacerbations: a prospective cohort study

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    Introduction: Identifying acute hypercapnic respiratory failure is crucial in the initial management of acute exacerbations of COPD. Guidelines recommend obtaining arterial blood samples but these are more difficult to obtain than venous. We assessed whether blood gas values derived from venous blood could replace arterial at initial assessment. Methods: Patients requiring hospital treatment for an exacerbation of COPD had paired arterial and venous samples taken. Bland–Altman analyses were performed to assess agreement between arterial and venous pH, CO2 and . The relationship between SpO2 and SaO2 was assessed. The number of attempts and pain scores for each sample were measured. Results: 234 patients were studied. There was good agreement between arterial and venous measures of pH and (mean difference 0.03 and −0.04, limits of agreement −0.05 to 0.11 and −2.90 to 2.82, respectively), and between SaO2 and SpO2 (in patients with an SpO2 of >80%). Arterial sampling required more attempts and was more painful than venous (mean pain score 4 (IQR 2–5) and 1 (IQR 0–2), respectively, p<0.001). Conclusions: Arterial sampling is more difficult and more painful than venous sampling. There is good agreement between pH and values derived from venous and arterial blood, and between pulse oximetry and arterial blood gas oxygen saturations. These agreements could allow the initial assessment of COPD exacerbations to be based on venous blood gas analysis and pulse oximetry, simplifying the care pathway and improving the patient experience

    Risk factors and outcome differences in hypoglycaemia-related hospital admissions: a case-control study in England

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    Aims: To evaluate risk factors for hospital admissions for hypoglycaemia and compare length of hospitalization, inpatient mortality and hospital readmission between hypoglycaemia- and nonhypoglycaemia-related admissions. Materials and methods: We used all admissions for hypoglycaemia in individuals with diabetes to English NHS hospital trusts between 2005 and 2014 (101 475 case admissions) and 3 random admissions per case in individuals with diabetes without hypoglycaemia (304 425 control admissions). Risk factors and differences in the 3 outcomes were estimated with logistic and negative binomial regressions. Results: A U-shaped relationship between age and risk of admission for hypoglycaemia was observed until the age of 85 years; compared to the nadir at 60 years, the risk was progressively higher in younger and older patients and steadily declined after 85 years. Social deprivation (positively) and comorbidities (negatively) were associated with the risk of admission for hypoglycaemia. Compared to Caucasians, other ethnic groups had lower (Bangladeshi, Pakistani,Indians) or higher (Caribbean) risk of admission for hypoglycaemia. Length of hospitalization was 26% shorter while risk of rehospitalization was 65% higher in individuals admitted for hypoglycaemia. Compared to admissions for hypoglycaemia, risk of inpatient mortality was 50% lower for unstable angina but higher for acute myocardial infarction (3 times), acute renal failure (5 times) or pneumonia (8 times). Conclusions: Among hospital-admitted individuals with diabetes, age, social deprivation, comorbidities and ethnicity are associated with higher frequency of hospitalization for hypoglycaemia. Admission for hypoglycaemia is associated with a greater risk of readmission, a shorter length of hospitalisation and a generally lower inpatient mortality compared to admissions for other medical conditions. These results could help in identifying at-risk groups to reduce the burden of hospitalization for hypoglycaemia

    Athena MIMOS II Mossbauer spectrometer investigation

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    M&ouml;ssbauer spectroscopy is a powerful tool for quantitative mineralogical analysis of Fe-bearing materials. The miniature M&ouml;ssbauer spectrometer MIMOS II is a component of the Athena science payload launched to Mars in 2003 on both Mars Exploration Rover missions. The instrument has two major components: (1) a rover-based electronics board that contains power supplies, a dedicated central processing unit, memory, and associated support electronics and (2) a sensor head that is mounted at the end of the instrument deployment device (IDD) for placement of the instrument in physical contact with soil and rock. The velocity transducer operates at a nominal frequency of 25 Hz and is equipped with two 57Co/Rh M&ouml;ssbauer sources. The reference source (5 mCi landed intensity), reference target (alpha-Fe2O3 plus alpha-Fe0), and PIN-diode detector are configured in transmission geometry and are internal to the instrument and used for its calibration. The analysis M&ouml;ssbauer source (150 mCi landed intensity) irradiates Martian surface materials with a beam diameter of 1.4 cm. The backscatter radiation is measured by four PIN-diode detectors. Physical contact with surface materials is sensed with a switch-activated contact plate. The contact plate and reference target are instrumented with temperature sensors. Assuming 18% Fe for Martian surface materials, experiment time is 6&ndash;12 hours during the night for quality spectra (i.e., good counting statistics); 1&ndash;2 hours is sufficient to identify and quantify the most abundant Fe-bearing phases. Data stored internal to the instrument for selectable return to Earth include M&ouml;ssbauer and pulse-height analysis spectra (512 and 256 channels, respectively) for each of the five detectors in up to 13 temperature intervals (65 M&ouml;ssbauer spectra), engineering data for the velocity transducer, and temperature measurements. The total data volume is 150 kB. The mass and power consumption are 500 g (400 g for the sensor head) and 2 W, respectively. The scientific measurement objectives of the M&ouml;ssbauer investigation are to obtain for rock, soil, and dust (1) the mineralogical identification of iron-bearing phases (e.g., oxides, silicates, sulfides, sulfates, and carbonates), (2) the quantitative measurement of the distribution of iron among these iron-bearing phases (e.g., the relative proportions of iron in olivine, pyroxenes, ilmenite, and magnetite in a basalt), (3) the quantitative measurement of the distribution of iron among its oxidation states (e.g., Fe2+, Fe3+, and Fe6+), and (4) the characterization of the size distribution of magnetic particles. Special geologic targets of the M&ouml;ssbauer investigation are dust collected by the Athena magnets and interior rock and soil surfaces exposed by the Athena Rock Abrasion Tool and by trenching with rover wheels
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