508 research outputs found

    Is life a thermal horizon ?

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    This talk aims at questioning the vanishing of Unruh temperature for an inertial observer in Minkovski spacetime with finite lifetime, arguing that in the non eternal case the existence of a causal horizon is not linked to the non-vanishing of the acceleration. This is illustrated by a previous result, the diamonds temperature, that adapts the algebraic approach of Unruh effect to the finite case.Comment: Proceedings of the conference DICE 2006, Piombino september 200

    Museums and the making of textile histories: Past, present, and future

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    Many different types of museums collect, document, and preserve textiles, interpreting them through temporary and semi-permanent exhibitions, publications, and web- site interventions – sometimes independently, sometimes as part of a broader histo- ry of art and design, science and technology, social history and anthropology, local history or world cultures (for example, see the range and approaches in major fash- ion capitals such as London, Paris, Milan, New York with a long tradition of textile production as well as consumption, and in manufacturing cities such as Krefeld, Lyon, Manchester). Nonetheless, textile-focused events seldom receive great public attention or crit- ical acclaim, with the possible exceptions of innovative temporary exhibitions such as Jean-Paul Leclercq, “Jouer la Lumière” (Paris, Les Arts Décoratifs, 2001); Thomas P. Campbell, “Tapestry in the Renaissance: Art and Magnificence” (New York, The Metropolitan Museum of Art, 2002); Amelia Peck et al., “Interwoven Globe. The Worldwide Textile Trade, 1500-1800” (New York, The Metropolitan Museum of Art, 2013-2014); John Styles, “Threads of Feeling” (London, The Foundling Hospital, 2010-2011; Colonial Williamsburg, 2014).1 The aims of this debate are to draw on the different cultural experiences and disciplinary backgrounds of participants: – To generate discussion over the role of museums in making and representing tex- tile histories. Museums are not only depositories of textile objects, but also write or make both public and academic history through displays and publications. But how does their work relate to university research and dissemination, feed such research, or react to it? How might interactions between museums and universities in different regions and cultures be developed in the future? – To consider where innovative museum work is being undertaken (locally, region- ally, nationally, internationally), wherein lies its innovation, and how it might suggest directions for the future (in collecting, interpretation, etc.). By interpreta- tion, I mean any analogue or digital explanation that contextualizes the objects on display. – To suggest that the most dynamic study of objects from 1500 to the present is no longer limited to art historians – indeed, that the focus in art history on textiles that belong within a well-established tradition of connoisseurship (in which tap- estries and high-end commissions for wall-hangings dominate) is being challenged by the adoption of a more inclusive approach among historians, design historians, and historians of material culture. [Lesley Miller] EAN: 978-2-917902-31-

    Line element in quantum gravity: the examples of DSR and noncommutative geometry

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    We question the notion of line element in some quantum spaces that are expected to play a role in quantum gravity, namely non-commutative deformations of Minkowski spaces. We recall how the implementation of the Leibniz rule forbids to see some of the infinitesimal deformed Poincare transformations as good candidates for Noether symmetries. Then we recall the more fundamental view on the line element proposed in noncommutative geometry, and re-interprete at this light some previous results on Connes' distance formula.Comment: some references added. Proceedings of the Second Workshop on Quantum Gravity and Noncommutative Geometry, Universidade Lusofona, Lisbon 22-24 September 200

    An algebraic Birkhoff decomposition for the continuous renormalization group

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    This paper aims at presenting the first steps towards a formulation of the Exact Renormalization Group Equation in the Hopf algebra setting of Connes and Kreimer. It mostly deals with some algebraic preliminaries allowing to formulate perturbative renormalization within the theory of differential equations. The relation between renormalization, formulated as a change of boundary condition for a differential equation, and an algebraic Birkhoff decomposition for rooted trees is explicited

    mycosis fungoides in childhood description and study of two siblings

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    Primary cutaneous T-cell lymphomas are exceedingly rare in children and adolescents. However, mycosis fungoides (MF) is the most frequent primary cutaneous lymphoma diagnosed in childhood. Two cases of MF in siblings (a 14-year-old boy and his 10-year-old sister) are reported. On the basis of clinical features (histopathological and immunophenotypical findings) a diagnosis of MF patch lesions was made in both siblings. Since recent data in the literature have underlined a high frequency of the HLA-DQB1*03 allele in patients with familial MF (including child patients), the HLA profile of the patients was analysed, indicating the presence of a haplotype (HLA-DQB1*03,*03 in the girl, HLA-DQB1*02,*03 in the boy) corresponding with that described in recent literature. Two rare and exceptional cases of MF in siblings are reported, highlighting the presence of a peculiar haplotype

    Minimal length in quantum space and integrations of the line element in Noncommutative Geometry

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    We question the emergence of a minimal length in quantum spacetime, comparing two notions that appeared at various points in the literature: on the one side, the quantum length as the spectrum of an operator L in the Doplicher Fredenhagen Roberts (DFR) quantum spacetime, as well as in the canonical noncommutative spacetime; on the other side, Connes' spectral distance in noncommutative geometry. Although on the Euclidean space the two notions merge into the one of geodesic distance, they yield distinct results in the noncommutative framework. In particular on the Moyal plane, the quantum length is bounded above from zero while the spectral distance can take any real positive value, including infinity. We show how to solve this discrepancy by doubling the spectral triple. This leads us to introduce a modified quantum length d'_L, which coincides exactly with the spectral distance d_D on the set of states of optimal localization. On the set of eigenstates of the quantum harmonic oscillator - together with their translations - d'_L and d_D coincide asymptotically, both in the high energy and large translation limits. At small energy, we interpret the discrepancy between d'_L and d_D as two distinct ways of integrating the line element on a quantum space. This leads us to propose an equation for a geodesic on the Moyal plane.Comment: 29 pages, 2 figures. Minor corrections to match the published versio

    Stressors in the ICU: different perceptions of patients, relatives and staff members

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    Introduction The high-risk critically ill are exposed to signifi cant stressors, along with diffi culties in communicating them to relatives and members of the staff . The aim of this study was to compare the perception of stressors as reported by patients (P), relatives (R) and ICU staff members (S). Methods A validated questionnaire [1] was used to quantitatively assess discomforts related to the ICU stay. Items were clustered into categories; higher scores refer to a higher stressfulness. The median (IQR) was calculated for each category. Twenty-eight high-risk critically ill at discharge, 55 relatives 48 hours after admission of their next of kin, and a total of 125 staff members (55 attending physicians, 40 nurses and 30 medical students/specialist trainees) were interviewed. Fifty-six of the staff members were used to keep patients consciously sedated as for local guidelines; the remaining used deeper levels of sedation. Nonparametric tests were used as needed. Results All stressor categories were diff erently reported by the three groups analysed: environmental (S = 17 (15 to 19), R = 15 (13 to 18), P = 10 (8 to 11), P <0.01), relationships (S = 23 (21 to 25), R = 20.5 (17 to 24.5), P = 14 (11 to 17), P <0.01), emotional (S = 25.5 (23 to 28), R = 24 (20 to 26), P = 18 (15 to 22), P <0.01), and physical (S = 35 (31 to 38), R = 33 (26.5 to 37), P = 27 (21 to 30), P <0.01). Among the staff members, nurses overestimated more than attending physicians, while trainees are closer to relatives\u2019 perception (P = 0.03). Staff members used to conscious sedation overestimate less the impact of environmental stressors (P = 0.03). Years of experience (r = 0.24, P = 0.03) and age (r = 0.27, P = 0.01) are related to stressor overestimation among staff members. Conclusion Members of the staff should reconsider their beliefs on patients\u2019 perception of stressors. We argue that such an overestimation may bring inappropriate administration of analgesic and sedative drugs, particularly for nurses and older members of staff . Relatives might be useful intermediaries to have a better insight of patients\u2019 perception
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