10,232 research outputs found

    Advanced space system analysis software. Technical, user, and programmer guide

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    The LASS computer program provides a tool for interactive preliminary and conceptual design of LSS. Eight program modules were developed, including four automated model geometry generators, an associated mass properties module, an appendage synthesizer module, an rf analysis module, and an orbital transfer analysis module. The existing rigid body controls analysis module was modified to permit analysis of effects of solar pressure on orbital performance. A description of each module, user instructions, and programmer information are included

    First-Order Vortex Lattice Melting and Magnetization of YBa2_2Cu3_3O$_{7-\delta}

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    We present the first non-mean-field calculation of the magnetization M(T)M(T) of YBa2_2Cu3_3O7−δ_{7-\delta} both above and below the flux-lattice melting temperature Tm(H)T_m(H). The results are in good agreement with experiment as a function of transverse applied field HH. The effects of fluctuations in both order parameter ψ(r)\psi({\bf r}) and magnetic induction BB are included in the Ginzburg-Landau free energy functional: ψ(r)\psi({\bf r}) fluctuates within the lowest Landau level in each layer, while BB fluctuates uniformly according to the appropriate Boltzmann factor. The second derivative (∂2M/∂T2)H(\partial^2 M/\partial T^2)_H is predicted to be negative throughout the vortex liquid state and positive in the solid state. The discontinuities in entropy and magnetization at melting are calculated to be ∼0.034 kB\sim 0.034\, k_B per flux line per layer and ∼0.0014\sim 0.0014~emu~cm−3^{-3} at a field of 50 kOe.Comment: 11 pages, 4 PostScript figures in one uuencoded fil

    Does Information and Agreement Equal Informed Consent?

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    The following essay is based on a talk delivered last summer in England and on the chapter Information, Decisions, and the Limits of Informed Consent, in (Michael Freeman and Andrew D. E. Lewis, eds.) Law and Medicine: Current Legal Issues 2000, Volume 3 (Oxford University Press, 2000). This version appears with permission of the publisher. For many years, a principal labor of bioethics has been to find a way of confiding medical decisions to patients and not to doctors. The foremost mechanism for doing so has been the doctrine of informed consent. Anxious as bioethicists and courts have been to promulgate this doctrine, they have been less anxious to discover how well it works. The bioethical tradition has been far more interested in articulating principle than testing practice

    Information, Decisions, and the Limits of Informed Consent

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    For many years, the heart\u27s wish of bioethics has been to confide medical decisions to patients and not to doctors. The favoured key to doing so has been the doctrine of informed consent. The theory of and hopes for that doctrine are well captured in the influential case of Caterbury v. Spence: \u27[t]rue consent to what happens to one\u27s self is the informed exercise of a choice, and that entails an opportunity to evaluate knoledgeably the options available and the risks attendant upon each\u27

    Computing equilibrium states of cholesteric liquid crystals in elliptical channels with deflation algorithms

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    We study the problem of a cholesteric liquid crystal confined to an elliptical channel. The system is geometrically frustrated because the cholesteric prefers to adopt a uniform rate of twist deformation, but the elliptical domain precludes this. The frustration is resolved by deformation of the layers or introduction of defects, leading to a particularly rich family of equilibrium configurations. To identify the solution set, we adapt and apply a new family of algorithms, known as deflation methods, that iteratively modify the free energy extremisation problem by removing previously known solutions. A second algorithm, deflated continuation, is used to track solution branches as a function of the aspect ratio of the ellipse and preferred pitch of the cholesteric.Comment: 9 pages, 6 figure

    Nodular lymphocyte predominant Hodgkin lymphoma behaves as a distinct clinical entity with good outcome: evidence from 14-year followup in the West of Scotland Cancer Network

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    Clinically and biologically, nodular lymphocyte predominant Hodgkin lymphoma (NLPHL) has much more in common with germinal-center derived B-cell non-Hodgkin lymphoma (NHL) than with classical Hodgkin lymphoma (cHL). Management of NLPHL remains controversial. In a 14-year multicenter series, 69 cases were analyzed, and the median follow-up was 53 months (range 11–165.) B-symptoms were present in only 4.3% of patients, and 81.1% of patients had stage I/II disease. Treatment was with radiotherapy (53.6%), chemotherapy (21.7%), combined modality (17.4%), and observation (7.2%). In all, 10.1% of patients relapsed and 2.9% of patients developed high-grade transformation to DLBCL. All relapses and transformations were salvageable. No patient died of their disease. The 5-year relapse-free survival was 92%, transformation-free survival 98.4%, and overall survival 100%. We conclude that NLPHL behaves as a distinct clinical entity, often presenting at an early stage without risk factors. It has an excellent outcome. It may be possible, in early-stage disease, to reduce the intensity of therapy in NLPHL, to single-modality radiotherapy, without affecting OS

    Hydrodynamic Spinodal Decomposition: Growth Kinetics and Scaling Functions

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    We examine the effects of hydrodynamics on the late stage kinetics in spinodal decomposition. From computer simulations of a lattice Boltzmann scheme we observe, for critical quenches, that single phase domains grow asymptotically like tαt^{\alpha}, with α≈.66\alpha \approx .66 in two dimensions and α≈1.0\alpha \approx 1.0 in three dimensions, both in excellent agreement with theoretical predictions.Comment: 12 pages, latex, Physical Review B Rapid Communication (in press
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