2,145 research outputs found

    High Temperature Superfluidity in Double Bilayer Graphene

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    Exciton bound states in solids between electrons and holes are predicted to form a superfluid at high temperatures. We show that by employing atomically thin crystals such as a pair of adjacent bilayer graphene sheets, equilibrium superfluidity of electron-hole pairs should be achievable for the first time. The transition temperatures are well above liquid helium temperatures. Because the sample parameters needed for the device have already been attained in similar graphene devices, our work suggests a new route towards realizing high-temperature superfluidity in existing quality graphene samples.Comment: 6 pages, 4 figures, effect of screening on superfluidity include

    Exploring site formation and building local contexts through wiggle-match radiocarbon dating: re-dating of the Firth of Clyde Crannogs, Scotland

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    There are at least four wooden intertidal platforms, also known as marine crannogs, in the Firth of Clyde, on the west coast of Scotland. The interpretation of these sites partly depends on their dating and, if coeval, they could point to the presence of a native maritime hub. Furthermore, the spatial coincidence with the terminus of the Antonine Wall has led to speculation about the role they may have played in Roman-native interaction during the occupation of southern Scotland in the early first millennium cal ad. Hence, a better absolute chronology is essential to evaluate whether the marine crannogs were contemporary with one another and whether they related to any known historic events. This article presents results of a wiggle-match dating project aimed at resolving these uncertainties at two of the sites in question, Dumbuck and Erskine Bridge crannogs. The results show that the construction of these sites pre-date direct Roman influence in Scotland. Furthermore, the results indicate that the two sites were built at least 300 years apart, forcing us to consider the possibility that they may have functioned in very different historical contexts. Other findings include technical observations on the fine shape of the radiocarbon calibration curve near the turn of the first millennia bc/ad and potential evidence for persistent contamination in decayed and exposed sections of waterlogged alder

    Fibromyalgia Syndrome: A Pathoneurological Basis of Disease

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    Fibromyalgia (also known as fibromyalgia syndrome, or FMS) is a condition which causes its victims to suffer a wide range of symptoms, most notably chronic musculoskeletal pain. Although the causes of fibromyalgia remain unknown, recent advances help elucidate the underlying pathophysiologies of this condition, and show that it is likely not a musculoskeletal condition, but rather a pathoneurological condition

    Assessing the Landscape: In Search of a Coherent Value Theory for Environmental Ethics

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    Environmental Ethics is concerned with developing a set of moral duties towards the natural world based upon a value theory, or a conception of what bears value. However, many environmental ethicists concern themselves primarily with the former and are lacking in the latter. This work surveys several prominent environmental ethicists and assesses their value theories, dividing them into two main schools: Kantian/individualist and holist. Both are found to be problematic in their articulation of a value theory. I propose a distinct value theory with a basis in the Buddhist metaphysical doctrine of codependent origination. In accepting this metaphysic, we are led to a conception of value in which there is a rational requirement to value both individuals and systems, but which is not susceptible to the problems of individualism or holism. I conclude by suggesting that my value theory, which I call “constitutive holism,” can provide a basis for a coherent environmental ethic

    Development and Validation of the Nebraska Department of Correctional Services Prison Classification System

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    Over the last 45 years, the Nebraska Department of Correctional Services (NDCS) has made two substantial changes to its classification system. The first system was created and implemented in the 1970s. In 2005, Patricia Hardyman was contracted to update and modify the classification and reclassification system. Using statistical analyses of available data, a set of prediction models were created to score inmates on items that predicted future infraction behavior. However, the primary issues of the tools were that inmates’ scores were routinely over-classified and that substantial uses of overrides (approximately 40%) were indicated. After a review of the tools’ development methods, several issues were identified, including: a small development sample, a lack of prediction and outcome item specificity, lack of item weighting, a less than optimal feature select strategy, inefficient validation techniques, and the tool’s inability to assess infraction prediction posttransfer. It was therefore determined that this system required major improvements and a research project was outlined and contracted by the University of Nebraska, Omaha

    Applied Organometallics: Cp*Co(III)-Catalysed C-H Functionalisation as a Maturing Tool for the Synthesis of Heterocyclic Compounds

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    Heterocycle compounds are prevalent throughout the natural world and therefore it is unsurprising that they have become a key component in many pharmaceutically relevant molecules. Unfortunately, synthetic methods for their preparation are often complicated and exhibit poor sustainability. In order to develop more efficient and sustainable routes to the synthesis of these useful and valuable heterocyclic compounds chemists have started to develop new innovative approaches. One approach which has provided a number of successes in recent times are synthetic procedures operating through a key direct C?H bond functionalisation step. This chapter highlights the state-of-the-art for preparing a diverse range of heterocyclic compounds using a cobalt-catalysed C?H bond functionalisation approach, specifically applying Cp*Co(iii)-type catalysts
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