322 research outputs found

    Origin and Significance of Wet Spots on Scraped Surfaces in the High Arctic

    Get PDF
    In the western Queen Elizabeth Islands, Northwest Territories, where most of the petroleum exploration in the High Arctic is being conducted, much of the low lying land is covered with sorted and non-sorted circles and polygons 0.5-2.0 m in diameter. ... Much of the oil-camp construction takes place on the coastal low-lands on polygonal surfaces composed of sandy to silty loams. When these surfaces are scraped and reworked for camp areas and air strips in summer, it is common for them to have numerous wet spots which become soft and spongy and of jelly-like consistency when equipment is moved across them .... a small study was conducted in 1972 at the Sunoco Camp no. 3002 on the northeast side of King Christian Island (77° 44'N, 101° 15'W), approximately 3.5 km from the sea. There the surface soils consist of fine marine sediments intermixed with small pebbles. The entire camp area and the Hercules landing strip are built on a surface covered with non-sorted polygons. ... Excavations were made on both the disturbed surface, where the damp spots occurred, as well as in the undisturbed area adjacent to the camp. ... From the information obtained during the excavations in each of the areas described, it is possible to understand more clearly the mechanisms responsible for the features. The wet spots in the cleared work-area are located at the foci of ground-ice accumulations which occur at the margins and intersections of the non-sorted patterned ground. The occurrence of ground-ice at the perimeters of the non-sorted polygons is explained by the contraction cracks which form and outline the patterned ground. Moisture from the scanty precipitation (especially blowing snow) accumulates in the cracks and eventually becomes incorporated in the underlying frozen ground as ice veins. Since the cracks are areas of greater moisture (as well as microhabitats), the plants tend to congregate in them and in turn reinforce the moisture content by (1) their greater moisture-holding capacity, (2) more efficient moisture entrapment, and (3) retarding the rate of thaw owing to the slightly greater insulation they provide. Once such a surface is disturbed, as it was in this case by light blading with a bulldozer, the vegetation is destroyed (at least the above- surface parts). Greater thawing may then occur, during which the moisture is drawn to the surface by capillary action as melting of the ground ice takes place. These bladed areas increase soil compaction and therefore thermal conductivity, and so melt is accelerated. In addition, the organic matter and remaining live plant material in the crack act as a "wick" drawing the moisture to the surface. A last but very important factor is the movement of heavy equipment over the surface. ... Their main area of concentration was in the work area in front of the camp where there was continual movement of equipment. The repetitive application of pressure over an area rich in ground ice ... has a "pumping" action whereby moisture is slowly forced to the surface. This constant agitation distributes the water throughout the mass, and the material becomes "quick" owing to the reduction of intergranular pore pressure. This results in loss of cohesion, and the material becomes spongy and jelly-like when pressure is applied. The practical significance of this brief investigation is that the wet spots will probably not increase in size or the surface deteriorate further, but in fact there should be an improvement. It appeared from discussion with camp managers on two islands that, after two or three summers of use of the surface and scraping, the wet spots dry out. The best approach to the use of these vegetated (and therefore ice-rich) non-sorted, patterned ground surfaces in the High Arctic is to clear the areas before thawing occurs in the spring, and if possible not to use them heavily during the first one or two summers. By the second or third summer much of the ground ice will have thawed, so there should be less chance of major problems with wet and soft spots - unless the summer is unusually wet, as it was 1973

    ‘Doing the best we can’: Registered Nurses' experiences and perceptions of patient safety in intensive care during COVID-19

    Get PDF
    Aims: To explore registered nurses' experiences of patient safety in intensive care during COVID-19.Design: A qualitative interview study informed by constructivism. Method: Semi-structured interviews were conducted and audio- recorded with 19 registered nurses who worked in intensive care during COVID-19 between May and July 2021. Interviews were transcribed verbatim and thematically analysed utilizing framework. Results: Two key themes were identified. ‘On a war footing’—an unprecedented situation which describes the situation nurses faced, and the actions are taken to prepare for the safe delivery of care. ‘Doing the best we can’—Safe Delivery of Care which describes the ramifications of the actions taken on short- and long-term patient safety including organization of care, missed and suboptimal care and communication. Both themes were embedded in the landscape of Staff Well-being and Peer Support. Conclusion: Nurses reported an increase in patient safety risks which they attributed to the dilution of skill mix and fragmentation of care. Nurses demonstrated an under-standing of the holistic and long-term impacts on patient safety and recovery from critical illness. Impact: This study explored the perceived impact of COVID-19 on patient safety in intensive care from a nursing perspective. Dilution of skill mix, where specialist critical care registered nurses were diluted with registered nurses with no critical care experience, and the fragmentation of care was perceived to lead to reduced quality of care and increased adverse events and risk of harm which were not consistently formally reported. Furthermore, nurses demonstrated a holistic and long-term appreciation of patient safety. These findings should be considered as part of future nursing work-force modelling and patient safety strategies by intensive care leaders and managers. No public or patient contribution to this study. The study aims and objectives were developed in collaboration with health care professional

    Inflammation Dynamically Regulates Steroid Hormone Metabolism and Action within Macrophages in Rheumatoid Arthritis  

    Get PDF
    Rationale: In inflammatory diseases such as rheumatoid arthritis (RA), steroid metabolism is a central component mediating the actions of immuno-modulatory glucocorticoids and sex steroids. However, the regulation and function of cellular steroid metabolism within key leukocyte populations such as macrophages remain poorly defined. In this study, the inflammatory regulation of global steroid metabolism was assessed in RA macrophages. Methods: Bulk RNA-seq data from RA synovial macrophages was used to assess transcripts encoding key enzymes in steroid metabolism and signalling. Changes in metabolism were assessed in synovial fluids, correlated to measures of disease activity and functionally validated in primary macrophage cultures. Results: RNA-seq revealed a unique pattern of differentially expressed genes, including changes in genes encoding the enzymes 11ÎČ-HSD1, SRD5A1, AKR1C2 and AKR1C3. These correlated with disease activity, favouring increased glucocorticoid and androgen levels. Synovial fluid 11ÎČ-HSD1 activity correlated with local inflammatory mediators (TNFα, IL-6, IL-17,), whilst 11ÎČ-HSD1, SRD5A1 and AKR1C3 activity correlated with systemic measures of disease and patient pain (ESR, DAS28 ESR, global disease activity). Changes in enzyme activity were evident in inflammatory activated macrophages in vitro and revealed a novel androgen activating role for 11ÎČ-HSD1. Together, increased glucocorticoids and androgens were able to suppress inflammation in macrophages and fibroblast-like-synoviocytes. Conclusions: This study underscores the significant increase in androgen and glucocorticoid activation within inflammatory polarized macrophages of the synovium, contributing to local suppression of inflammation. The diminished profile of inactive steroid precursors in postmenopausal women may contribute to disturbances in this process, leading to increased disease incidence and severity.<br/

    The Intentional Use of Service Recovery Strategies to Influence Consumer Emotion, Cognition and Behaviour

    Get PDF
    Service recovery strategies have been identified as a critical factor in the success of. service organizations. This study develops a conceptual frame work to investigate how specific service recovery strategies influence the emotional, cognitive and negative behavioural responses of . consumers., as well as how emotion and cognition influence negative behavior. Understanding the impact of specific service recovery strategies will allow service providers' to more deliberately and intentionally engage in strategies that result in positive organizational outcomes. This study was conducted using a 2 x 2 between-subjects quasi-experimental design. The results suggest that service recovery has a significant impact on emotion, cognition and negative behavior. Similarly, satisfaction, negative emotion and positive emotion all influence negative behavior but distributive justice has no effect

    Observation of exclusive DVCS in polarized electron beam asymmetry measurements

    Full text link
    We report the first results of the beam spin asymmetry measured in the reaction e + p -> e + p + gamma at a beam energy of 4.25 GeV. A large asymmetry with a sin(phi) modulation is observed, as predicted for the interference term of Deeply Virtual Compton Scattering and the Bethe-Heitler process. The amplitude of this modulation is alpha = 0.202 +/- 0.028. In leading-order and leading-twist pQCD, the alpha is directly proportional to the imaginary part of the DVCS amplitude.Comment: 6 pages, 5 figure

    eta-prime photoproduction on the proton for photon energies from 1.527 to 2.227 GeV

    Full text link
    Differential cross sections for the reaction gamma p -> eta-prime p have been measured with the CLAS spectrometer and a tagged photon beam with energies from 1.527 to 2.227 GeV. The results reported here possess much greater accuracy than previous measurements. Analyses of these data indicate for the first time the coupling of the etaprime N channel to both the S_11(1535) and P_11(1710) resonances, known to couple strongly to the eta N channel in photoproduction on the proton, and the importance of j=3/2 resonances in the process.Comment: 6 pages, 3 figure

    Numerical evaluation of inflationary 3-point functions on curved field space

    Get PDF
    We extend the public CppTransport code to calculate the statistical properties of fluctuations in multiple-field inflationary models with curved field space. Our implementation accounts for all physical effects at tree-level in the 'in-in' diagrammatic expansion. This includes particle production due to time-varying masses, but excludes scenarios where the curvature perturbation is generated by averaging over the decay of more than one particle. We test our implementation by comparing results in Cartesian and polar field-space coordinates, showing excellent numerical agreement and only minor degradation in compute time. We compare our results with the PyTransport 2.0 code, which uses the same computational approach but a different numerical implementation, finding good agreement. Finally, we use our tools to study a class of gelaton-like models which could produce an enhanced non-Gaussian signal on equilateral configurations of the Fourier bispectrum. We show this is difficult to achieve using hyperbolic field-space manifolds and simple inflationary potentials

    Designing a new science-policy communication mechanism for the UN Convention to Combat Desertification

    Get PDF
    The United Nations Convention to Combat Desertification (UNCCD) has lacked an efficient mechanism to access scientific knowledge since entering into force in 1996. In 2011 it decided to convene an Ad Hoc Working Group on Scientific Advice (AGSA) and gave it a unique challenge: to design a new mechanism for science-policy communication based on the best available scientific evidence. This paper outlines the innovative 'modular mechanism' which the AGSA proposed to the UNCCD in September 2013, and how it was designed. Framed by the boundary organization model, and an understanding of the emergence of a new multi-scalar and polycentric style of governing, the modular mechanism consists of three modules: a Science-Policy Interface (SPI); an international self-governing and self-organizing Independent Non-Governmental Group of Scientists; and Regional Science and Technology Hubs in each UNCCD region. Now that the UNCCD has established the SPI, it is up to the worldwide scientific community to take the lead in establishing the other two modules. Science-policy communication in other UN environmental conventions could benefit from three generic principles corresponding to the innovations in the three modules-joint management of science-policy interfaces by policy makers and scientists; the production of synthetic assessments of scientific knowledge by autonomous and accountable groups of scientists; and multi-scalar and multi-directional synthesis and reporting of knowledge

    A Bayesian analysis of pentaquark signals from CLAS data

    Get PDF
    We examine the results of two measurements by the CLAS collaboration, one of which claimed evidence for a Θ+\Theta^{+} pentaquark, whilst the other found no such evidence. The unique feature of these two experiments was that they were performed with the same experimental setup. Using a Bayesian analysis we find that the results of the two experiments are in fact compatible with each other, but that the first measurement did not contain sufficient information to determine unambiguously the existence of a Θ+\Theta^{+}. Further, we suggest a means by which the existence of a new candidate particle can be tested in a rigorous manner.Comment: 5 pages, 3 figure

    Electron Scattering From High-Momentum Neutrons in Deuterium

    Full text link
    We report results from an experiment measuring the semi-inclusive reaction d(e,eâ€Čps)d(e,e'p_s) where the proton psp_s is moving at a large angle relative to the momentum transfer. If we assume that the proton was a spectator to the reaction taking place on the neutron in deuterium, the initial state of that neutron can be inferred. This method, known as spectator tagging, can be used to study electron scattering from high-momentum (off-shell) neutrons in deuterium. The data were taken with a 5.765 GeV electron beam on a deuterium target in Jefferson Laboratory's Hall B, using the CLAS detector. A reduced cross section was extracted for different values of final-state missing mass W∗W^{*}, backward proton momentum p⃗s\vec{p}_{s} and momentum transfer Q2Q^{2}. The data are compared to a simple PWIA spectator model. A strong enhancement in the data observed at transverse kinematics is not reproduced by the PWIA model. This enhancement can likely be associated with the contribution of final state interactions (FSI) that were not incorporated into the model. A ``bound neutron structure function'' F2neffF_{2n}^{eff} was extracted as a function of W∗W^{*} and the scaling variable x∗x^{*} at extreme backward kinematics, where effects of FSI appear to be smaller. For ps>400p_{s}>400 MeV/c, where the neutron is far off-shell, the model overestimates the value of F2neffF_{2n}^{eff} in the region of x∗x^{*} between 0.25 and 0.6. A modification of the bound neutron structure function is one of possible effects that can cause the observed deviation.Comment: 33 pages RevTeX, 9 figures, to be submitted to Phys. Rev. C. Fixed 1 Referenc
    • 

    corecore