601,061 research outputs found

    The complete LQG propagator: I. Difficulties with the Barrett-Crane vertex

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    Some components of the graviton two-point function have been recently computed in the context of loop quantum gravity, using the spinfoam Barrett-Crane vertex. We complete the calculation of the remaining components. We find that, under our assumptions, the Barrett-Crane vertex does not yield the correct long distance limit. We argue that the problem is general and can be traced to the intertwiner-independence of the Barrett-Crane vertex, and therefore to the well-known mismatch between the Barrett-Crane formalism and the standard canonical spin networks. In a companion paper we illustrate the asymptotic behavior of a vertex amplitude that can correct this difficulty.Comment: 31 page

    A Systematic Derivation of the Riemannian Barrett-Crane Intertwiner

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    The Barrett-Crane intertwiner for the Riemannian general relativity is systematically derived by solving the quantum Barrett-Crane constraints corresponding to a tetrahedron (except for the non-degeneracy condition). It was shown by Reisenberger that the Barrett-Crane intertwiner is the unique solution. The systematic derivation can be considered as an alternative proof of the uniqueness. The new element in the derivation is the rigorous imposition of the cross-simplicity constraint.Comment: 10 page

    Medical Literary Messenger (Vol. 4, No. 1, Fall/Winter 2016)

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    Irene—London, December 2006 / Katharine Harer -- Today / Antonia Lewandowski -- The Bench / Richard LeBlond -- illustration / Alana Barrett -- After Reading Elizabeth Bishop’s “In the Waiting Room” / Nina Bannett -- How to Open Your Eyes / Angus Woodward -- Stage 3 / Amanda Gomez -- NeuroSkull / Alana Barrett -- It / Grace Fryberger -- The Mammogram, Part II / Katharine Harer -- Old and New / Derick Nelson Jenkins -- The Innoculation / Simon Friedman -- illustrations / Alana Barrett -- Shocking / Phyllis Price -- Boutique Hotel / Lynn Ciesielski -- A Sleeping Cancer Cell / Theresa Thekkudan -- After Years / Sophie Shaw -- illustration / Alana Barrett -- Taking Note / Iain Macdonald -- The View from the Hospital / Li Yun Alvarado -- Comfort / Wei-Li Suen -- Taking My Father Hostage / Kathryn Trueblood -- Going Blind in One Eye / Craig W. Steele -- Hollywood Cemetery / Michael P. Stevens -- Scald / Dan Campion -- Brain Injury / Grace Fryberger -- Blind Skulls / Alana Barrett -- Stitches / Courtney LeBlanc -- Cardioplegia / Ina Roy-Faderman -- Riding the Rails / Derick Nelson Jenkins -- Rebecca at the End / Sheryl Slocum

    where angels fear to tread : Tracing the Journey of the Female Poet in Aurora Leigh

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    Through Aurora Leigh, Elizabeth Barrett Browning explores the role of female poets as agents of social change in the Victorian society. During the Victorian period, the role of women was largely confined to the domestic setting. While women were allowed to write, female writers were limited to the realm of novels, which was perceived by the Victorian society to be the less distinguished genre. In writing Aurora Leigh, Barrett Browning challenged this gender stereotype by producing a novel-poem that unites the feminine voice with masculine authority and superiority. Like Barrett Browning, Aurora Leigh, in her fictional role as a writer, also challenges the same stereotypes. She seeks to redefine poetry, which is the domain of man. In rejecting Romney’s initial marriage proposal, Aurora Leigh also rebels against the stereotypical gender roles. At the same time, in doing so, she inadvertently rejects Romney’s plan for social change that involves only the physical aspect. Instead, in pursuing her career as a poet, Aurora Leigh finds herself in a position to bring about social change on a level that transcends the physical. By telling the story of Marian Erle, Aurora Leigh has the power to change the plight of women in the Victorian society. Finally, being women themselves, both Barrett Browning and Aurora Leigh can speak up for the Victorian women even more effectively

    Ecological study of Barrett Domain, New Plymouth

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    An ecological survey of Barrett Domain (New Plymouth) was conducted by the Environmental Research Institute, University of Waikato, for the New Plymouth District Council. The main ecological features of the domain were mapped and described, preliminary ecological impact assessments of domain upgrades were conducted, and recommendations made for the future management of the site. Barrett Domain encompasses a regionally significant wetland habitat (Barrett Lake), several hectares of remnant semi-coastal forest and areas of well-established planted native species. Wetland vegetation around Barrett Lake comprised reedland (kuta, raupo) and flaxland, and the lake provides refuge to a number of indigenous water birds. Semi-coastal forest at the site was dominated by tawa, kohekohe and pukatea, with a diverse range of understory and epiphyte species. Planted natives included a significant kauri grove, and patches of pohutukawa and puriri. Swamp forest to the west of the lake comprised mature pukatea and swamp maire, and if acquired in the land transfer, the ecological value of the domain would be greatly enhanced. Four permanent i-Tree vegetation monitoring plots and a National Wetland Monitoring plot were established at the domain and should be re-measured at 5 yearly intervals. Any ecological impacts associated with the construction of a path around the perimeter of Barrett Lake could be offset by restoration planting at the southern lake margin. Management recommendations include: • Restoration planting with appropriate native species at the southern lake margin and several other key areas within the domain. • Removing/monitoring exotic species, including the gorse and grey willow on the lake margin, and wandering Jew and climbing asparagus in the forest remnants. • Fencing (stock proofing) the swamp forest at the west of the lake once it is acquired. • Continuing with pest control and monitoring. • Obtaining new interpretive signage

    Linfield College: Study Abroad in France

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    This letter from returnee Kate Barrett explains the value of studying abroad in France
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