893 resultados para Control and Systems Engineering
Resumo:
This article seeks to provoke a deeper engagement of Critical Security Studies with security's relations to technology and weapons. It explores existing assumptions about these relations in mainstream arms control and disarmament theory, and the way such assumptions are deployed and distributed in the current settlement of arms control and disarmament practice. It then draws on recent social and philosophical discussions of materiality, particularly on the thought of Bruno Latour, to propose a different set of concepts for exploring the aims and limits of arms control and disarmament. These concepts emphasise the mediating roles of material things in social relations and they may offer a richer view of the object of arms control (weapons and violence) and of the practices of arms limitation and reduction; one that may ultimately gesture towards a different understanding of arms politics, and that may be used to explore the transformatory potentials of arms control and disarmament.
Resumo:
The use of schemes involving multiple laser pulses to enhance and control the properties of beams of protons accelerated in ultra-intense laser irradiation of planar foil targets is discussed. Specifically, the schemes include the use of a second laser pulse to produce and control preplasma expansion of the target to enhance energy coupling to the proton beam; the use of a second laser pulse to drive shock deformation of the target to change the direction of the proton beam; and a scheme involving dual high intensity laser pulses to change the properties of the sheath field, with the aim of modifying the proton energy spectrum. An overview of our recent experimental and theoretical results is given. The overall aim of this work is to determine the extent to which the properties of the sheath-accelerated proton beam can be optically controlled, to enable beam delivery at high repetition rates. To cite this article: D.C. Carroll et al., C. R. Physique 10 (2009). (C) 2009 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.
Resumo:
The purpose of this paper is to examine the manner in which beliefs relating to sense of control and perceived social support mediate the impact of objective circumstances on psychological distress. In particular it focuses on the nature of the interaction between such variables. The results provide no evidence favouring the displacement hypothesis whereby the benefits of social support involve costs in terms of independence. Consistent support, however, is found for the functional substitution hypothesis. The conclusion is unaffected by the introduction of distinctions relating to types of support and types of power.
Resumo:
Objective: The authors evaluated the results of primary transpupillary thermotherapy for choroidal melanoma in 100 cases. Design: Prospective nonrandomized analysis of treatment method. Participants: One hundred patients with choroidal melanoma were studied. Main Outcome Measures: Tumor response, ocular side effects, and visual results. Results: Of 100 consecutive patients with choroidal melanoma treated with transpupillary thermotherapy, the mean tumor basal diameter was 7.1 mm and tumor thickness was 2.8 mm. The tumor margin touched the optic disc in 34 eyes (34%) and was beneath the fovea in 42 eyes (42%). Documented growth was present in 64 eyes (64%), and known clinical risks for growth were present in all of the remaining 36 eyes (36%), with an average of 4 of 5 statistical risk factors for growth per tumor. After a mean of three treatment sessions and 14 months of follow-up, the mean tumor thickness was reduced to 1.4 mm. Treatment was successful in 94 eyes (94%) and failed in 6 eyes (6%). Three patients with amelanotic tumors showed no initial response to thermotherapy, but subsequent intravenous indocyanine green administration during thermotherapy resulted in improved heat absorption and tumor regression to a flat scar. The six eyes classified as treatment failures included four eyes with tumors that showed partial or no response to thermotherapy, thus requiring plaque radiotherapy or enucleation, and two eyes with recurrence, subsequently controlled with additional thermotherapy. After treatment, the visual acuity was the same (within 1 line) or better than the pretreatment visual acuity in 58 eyes (58%) and worse in 42 eyes (42%). The main reasons for poorer vision included treatment through the foveola for subfoveal tumor (25 eyes), retinal traction (10 eyes), retinal vascular obstruction (5 eyes), optic disc edema (1 eye), and unrelated ocular ischemia (1 eye). Temporal location (versus nasal and superior, P = 0.02) and greater distance from the optic disc (P = 0.04) were risks for retinal traction. Conclusions: Transpupillary thermotherapy may be an effective treatment for small posterior choroidal melanoma, especially those near the optic disc and fovea. Despite satisfactory local tumor control, ocular side effects can result in decreased vision. Longer follow- up will be necessary to assess the impact of thermotherapy on ultimate local tumor control and metastatic disease.
Resumo:
This article explores the relation between humour and control, drawing on participant observation in an organization in which humour was central to daily life. Keys is a leading advertising agency whose staff spent an unusually large amount of time sending humorous e-mails. Examining these e-mails in some depth, we unpack the role of humour in subverting various forms of control, including gender norms and managerial authority. We find the relation between humour, control and subversion to be ambiguous. Building upon current debates in organization studies, we develop the concept of humour based on our observations at Keys. Specifically, we argue that humour is always in excess of both control and subversion, a 'nicely impossible' object that cannot be captured. This article thus contributes to theoretical approaches on organizational humour, conceptualizing the concept of 'newness' through Judith Butler's re-reading of Derridean différance and the Lacanian Real. In addition, we contribute a novel empirical account of the study of e-mail list humour in a contemporary advertising firm. © 2012 Blackwell Publishing Ltd.