2,498 research outputs found

    Formation of a quasicrystalline Pb monolayer on the ten-fold surface of the decagonal Al-Ni-Co quasicrystal

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    Lead has been deposited on the ten-fold surface of decagonal Al72Ni11Co17 to form an epitaxial quasicrystalline single-element monolayer. The overlayer grows through nucleation of nanometer-sized irregular islands and the coverage saturates at 1 ML. The overlayer is well-ordered quasiperiodically as evidenced by LEED and Fourier transforms of STM images. Annealing the film to 600 K improves the structural quality, but causes the evaporation of some material such that the film develops pores. Electronic structure measurements using X-ray photoemission spectroscopy indicate that the chemical interaction of the Pb atoms with the substrate is weak.Comment: 12 pages, 5 figure

    Misdiagnosis, Mistreatment, and Harm - When Medical Care Ignores Social Forces.

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    The Case Studies in Social Medicine demonstrate that when physicians use only biologic or individual behavioral interventions to treat diseases that stem from or are exacerbated by social factors, we risk harming the patients we seek to serve

    Sex on the brain! Associations between sexual activity and cognitive function in older age

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    Background: the relationship between cognition and sexual activity in healthy older adults is under-researched. A limited amount of research in this area has shown that sexual activity is associated with better cognition in older men. The current study explores the possible mediating factors in this association in men and women, and attempts to provide an explanation in terms of physiological influences on cognitive function. Methods: using newly available data from Wave 6 of the English Longitudinal Study of Ageing, the current study explored associations between sexual activity and cognition in adults aged 50–89 (n = 6,833). Two different tests of cognitive function were analysed: number sequencing, which broadly relates to executive function, and word recall, which broadly relates to memory. Results: after adjusting for age, education, wealth, physical activity, depression, cohabiting, self-rated health, loneliness and quality of life, there were significant associations between sexual activity and number sequencing and recall in men. However, in women there was a significant association between sexual activity and recall, but not number sequencing. Conclusions: possible mediators of these associations (e.g. neurotransmitters) are discussed. The cross-sectional nature of the analysis is limiting, but provides a promising avenue for future explorations and longitudinal studies. The findings have implications for the promotion of sexual counselling in healthcare settings, where maintaining a healthy sex life in older age could be instrumental in improving cognitive function and well-being

    Work function of a quasicrystal surface: Icosahedral Al–Pd–Mn

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    The work function of a surface is one of its most basic and influential features. It has long been recognized that work function controls thermionic and field emission. The work function of a solid surface affects charge transfer to or from an adsorbate. It influences the electron tunneling probability between surfaces. It plays a role in quantization of electron states parallel to the surface in metal-supported metallic nanoislands. There is also evidence linking the work function of a metal surface to its friction coefficient

    How to humiliate and shame: A reporter's guide to the power of the mugshot

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    This is an Author's Accepted Manuscript of an article published in Social Semiotics, 24(1), 56-87, 2014, copyright Taylor & Francis, available online at: http://www.tandfonline.com/The judicial photograph – the “mugshot” – is a ubiquitous and instantly recognisable form, appearing in the news media, on the internet, on book covers, law enforcement noticeboards and in many other mediums. This essay attempts to situate the mugshot in a historical and theoretical context to explain the explicit and implicit meaning of the genre as it has developed, focussing in particular on their use in the UK media in late modernity. The analysis is based on the author's reflexive practice as a journalist covering crime in the national news media for 30 years and who has used mugshots to illustrate stories for their explicit and specific content. The author argues that the visual limitations of the standardised “head and shoulders” format of the mugshot make it a robust subject for analysing the changing meaning of images over time. With little variation in the image format, arguments for certain accreted layers of signification are easier to make. Within a few years of the first appearance of the mugshot form in the mid-19th century, it was adopted and adapted as a research tool by scientists and criminologists. While the positivist scientists claimed empirical objectivity we can now see that mugshots played a part in the construction of subjective notions of “the other”, “the lesser” or “sub-human” on the grounds of class, race and religion. These dehumanising ideas later informed the theorists and bureaucrats of National Socialist ideology from the 1920s to 1940s. The author concludes that once again the mugshot has become, in certain parts of the media, a signifier widely used to exclude or deride certain groups. In late modernity, the part of the media that most use mugshots – the tabloid press and increasingly tabloid TV – is part of a neo-liberal process that, in a conscious commercial appeal to the paying audience, seeks to separate rather than unify wider society

    Assessing temporal genetic variation in a cougar population: influence of harvest and neighboring populations

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    The geography of the Black Hills region of South Dakota and Wyoming may limit connectivity for many species. For species with large energetic demands and large home ranges or species at low densities this can create viability concerns. Carnivores in this region, such as cougars (Puma concolor), have the additive effect of natural and human-induced mortality; this may act to decrease long-term viability. In this study we set out to explore genetic diversity among cougar populations in the Black Hills and surrounding areas. Specifically, our objectives were to first compare genetic variation and effective number of breeders of cougars in the Black Hills during three harvest regimes: pre (2003–2006), moderate (2007–2010), and heavy (2011–2013), to determine if harvest impacted genetic variation. Second, we compared genetic structure of the Black Hills cougar population with cougar populations in neighboring eastern Wyoming and North Dakota. Using 20 microsatellite loci, we conducted genetic analysis on DNA samples from cougars in the Black Hills (n = 675), North Dakota (n = 113), and eastern Wyoming (n = 62) collected from 2001–2013. Here we report that the Black Hills cougar population maintained genetic variation over the three time periods. Our substructure analysis suggests that the maintenance of genetic variation was due to immigration from eastern Wyoming and possibly North Dakota

    Structure and Stability of the Twofold Surface of Icosahedral Al-Pd-Mn by Low-Energy Electron Diffraction and X-Ray Photoemission Spectroscopy

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    We have used low-energy electron diffraction and x-ray photoemission spectroscopy to investigate the structure of the twofold surface of icosahedral Al-Pd-Mn. The regrowth of the surface by annealing after sputtering took place in two distinct stages. The first stage was the appearance of a fine-grained surface phase with icosahedral, or near-icosahedral, symmetry. For higher annealing temperatures (above 800 K) a bulk terminated face-centered icosahedral surface was observed
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