34 research outputs found

    Generalized Global Defect Solutions

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    We investigate the presence of defect structures in generalized models described by real scalar field in (1,1)(1,1) space-time dimensions. We work with two distinct generalizations, one in the form of a product of functions of the field and its derivative, and the other as a sum. We search for static solutions and study the corresponding linear stability on general grounds. We illustrate the results with several examples, where we find stable defect structures of modified profile. In particular, we show how the new defect solutions may give rise to evolutions not present in the standard scenario in higher spatial dimensions.Comment: RevTex, 10 pages, 2 figures; version to appear in EPJ

    UV and EUV Instruments

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    We describe telescopes and instruments that were developed and used for astronomical research in the ultraviolet (UV) and extreme ultraviolet (EUV) regions of the electromagnetic spectrum. The wavelength ranges covered by these bands are not uniquely defined. We use the following convention here: The EUV and UV span the regions ~100-912 and 912-3000 Angstroem respectively. The limitation between both ranges is a natural choice, because the hydrogen Lyman absorption edge is located at 912 Angstroem. At smaller wavelengths, astronomical sources are strongly absorbed by the interstellar medium. It also marks a technical limit, because telescopes and instruments are of different design. In the EUV range, the technology is strongly related to that utilized in X-ray astronomy, while in the UV range the instruments in many cases have their roots in optical astronomy. We will, therefore, describe the UV and EUV instruments in appropriate conciseness and refer to the respective chapters of this volume for more technical details.Comment: To appear in: Landolt-Boernstein, New Series VI/4A, Astronomy, Astrophysics, and Cosmology; Instruments and Methods, ed. J.E. Truemper, Springer-Verlag, Berlin, 201

    Human Health Risk Assessment For Arsenic: A Critical Review

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    Millions of people are exposed to arsenic resulting in a range of health implications.This paper provides an up-to-date review of the different sources of arsenic (water, soil and food), indicators of human exposure (biomarker assessment of hair, nail, urine and blood), epidemiological and toxicological studies on carcinogenic and non-carcinogenic health outcomes, and risk assessment approaches. The review demonstrates a need for more work evaluating the risks of different arsenic species such as; arsenate, arsenite monomethylarsonic acid, monomethylarsonous acid, dimethylarsinic acid and dimethylarsinous acid as well as a need to better integrate the different exposure sources in risk assessments

    The bomb in my backyard, the serpent in my house: environmental justice, risk, and the colonisation of attachment

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    Theorists have argued that environmental justice requires more than just the fair distribution of environmental benefits and harms. It also requires participation in environmental decisions of those affected by them, and equal recognition of their cultural identities, dimensions most clearly articulated in relation to indigenous struggles, where past devaluation of place-based cultural identities is seen as a source of injustice. I argue for an alternative concept of environmental justice that draws on accounts of how attachment (and place attachment specifically) is constitutive for both self-efficacy and collective agency in the face of an intrinsically uncertain future. Drawing on the work of Peter Marris and using a case study of UK gas pipeline infrastructure, I show how disruption to attachments also disrupts lived strategies for dealing with an uncertain future. The source of injustice involved in such disruption should be viewed as the ‘colonisation of attachment’
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