18,203 research outputs found

    Contributions of Vacuum and Plasmon Modes to the Force on a Small Sphere near a Plate

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    The force on a small sphere with a plasma model dielectric function and in the presence of a perfectly reflecting plane is considered. The contribution of both the vacuum modes of the quantized electromagnetic field and of plasmon modes in the sphere are discussed. In the case that the plasmon modes are in their ground state, quasi-oscillatory terms from the vacuum and plasmon parts cancel one another, leading a monotonic attractive force. If the plasmon modes are not in the ground state, the net force is quasi-oscillatory. In both cases, the sphere behaves in the same way as does an atom in either its ground state or an excited state.Comment: 7 pages, no figures, talk presented at "Quantum Fields under External Conditions - 2005", Barcelona, Spain, September 200

    Research into alternative network approaches for space operations

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    The main goal is to resolve the interoperability problem of applications employing DOD TCP/IP (Department of Defence Transmission Control Protocol/Internet Protocol) family of protocols on a CCITT/ISO based network. The objective is to allow them to communicate over the CCITT/ISO protocol GPLAN (General Purpose Local Area Network) network without modification to the user's application programs. There were two primary assumptions associated with the solution that was actually realized. The first is that the solution had to allow for future movement to the exclusive use of the CCITT/ISO standards. The second is that the solution had to be software transparent to the currently installed TCP/IP and CCITT/ISO user application programs

    Convergence and divergence dynamics in British and French business schools: how will the pressure for accreditation influence these dynamics?

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    This paper focuses on convergence and divergence dynamics among leading British and French business schools and explores how the pressure for accreditation influences these dynamics. We illustrate that despite historical differences in approaches to management education in Britain and France, these approaches have converged partly based on the influence of the American model of management education but more recently through the pursuit of accreditation, in particular AASCB and EQUIS. We explore these dynamics through the application of the resource-based view of the firm and institutional theory and suggest that whilst achieving accreditation is a necessary precursor for international competition, it is no longer a form of competitive advantage. The pursuit of accreditation has fostered a form of competitive mimicry reducing national distinctiveness. The resource-based view of the firm suggests that the top schools need a more heterogeneous approach that is not easily replicable if they are to outperform the competitors. Consequently, the convergence of management education in Britain and France will become a new impetus for divergence. We assert that future growth and competitive advantage might be better achieved through the reassertion of national, regional and local cultural characteristics

    Older Adults at Risk for Atrial Fibrillation Lack Knowledge and Confidence to Seek Treatment for Signs and Symptoms.

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    Early detection of atrial fibrillation (AF) is crucial for averting AF-related stroke and heart failure, but treatment is delayed when AF is not recognized. The critical need for early detection and treatment requires education to promote AF awareness. Knowledge deficits, attitudes, and beliefs about AF that should be addressed to improve awareness and reduce treatment-seeking delay in older adults at risk for developing AF have not been well documented. The purpose of this study was to describe knowledge, treatment-seeking attitudes, and beliefs about AF in adults ⩟ 65 years old and identify demographic characteristics associated with knowledge, attitudes, and beliefs. Patients with no history of AF recruited from an academic medical center were interviewed using the Knowledge, Attitudes, and Beliefs about Atrial Fibrillation Survey. Data were analyzed using descriptive statistics and independent t tests. Participants (N = 180) were 63% male with a mean age of ±3.± 6.0 years, and 52% held ⩟ 4-year college degree. About one third could not identify common symptoms of AF including palpitations (31%), chest pain (36%), dyspnea (30%), and fatigue (35%). A majority (84%) lacked confidence to recognize AF, and 58% were not sure when they should seek care for AF symptoms. Nearly a third (32%) believed palpitations are always present with AF, and 74% believed that low energy would not be their only symptom of AF. Higher scores for AF Symptom Knowledge (p = .02) were observed in females, and General Knowledge about AF was greater for younger participants (p < .001). Participants lacked knowledge and confidence to aid decision-making for treatment-seeking for symptoms of AF and held inaccurate beliefs about AF that could hinder early treatment-seeking. Programs to promote AF awareness should explain the spectrum of symptoms that may be manifested by AF and include action plans for responding to symptoms

    Common Mitochondrial DNA Mutations Generated through DNA-Mediated Charge Transport

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    Mutation sites that arise in human mitochondrial DNA as a result of oxidation by a rhodium photooxidant have been identified. HeLa cells were incubated with [Rh(phi)2bpy]Cl3 (phi is 9,10-phenanthrenequinone diimine), an intercalating photooxidant, to allow the complex to enter the cell and bind mitochondrial DNA. Photoexcitation of DNA-bound [Rh(phi)2bpy]3+ can promote the oxidation of guanine from a distance through DNA-mediated charge transport. After two rounds of photolysis and growth of cells incubated with the rhodium complex, DNA mutations in a portion of the mitochondrial genome were assessed via manual sequencing. The mutational pattern is consistent with dG to dT transversions in the repetitive guanine tracts. Significantly, the mutational pattern found overlaps oxidative damage hot spots seen previously. These mutations are found within conserved sequence block II, a critical regulatory element involved in DNA replication, and these have been identified as sites of low oxidation potential to which oxidative damage is funneled. On the basis of this mutational analysis and its correspondence to sites of long-range oxidative damage, we infer a critical role for DNA charge transport in generating these mutations and, thus, in regulating mitochondrial DNA replication under oxidative stress

    Comparison of the full potential and Euler formulations for computing transonic airfoil flows

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    A quantitative comparison between the Euler and full potential formulations with respect to speed and accuracy is presented. The robustness of the codes used is tested by a number of transonic airfoil cases. The computed results are from four transonic airfoil computer codes. The full potential codes use fully implicit iteration algorithms. The first Euler code uses a fully implicit ADI iteration scheme. The second Euler code uses an explicit Runge Kutta time stepping algorithm which is enhanced by a multigrid convergence acceleration scheme. Quantitative comparisons are made using various plots of lift coefficient versus the average mesh spacing along the airfoil. Besides yielding an asymptotic limit to the lift coefficient, these results also demonstrate the truncation error behavior of the various codes. Quantitative conclusions regarding the full potential and Euler formulations with respect to accuracy, speed, and robustness can be presented

    Translating evidence-based guidelines to improve feedback practices:the interACT case study

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    Background: There has been a substantial body of research examining feedback practices, yet the assessment and feedback landscape in higher education is described as ‘stubbornly resistant to change’. The aim of this paper is to present a case study demonstrating how an entire programme’s assessment and feedback practices were re-engineered and evaluated in line with evidence from the literature in the interACT (Interaction and Collaboration via Technology) project.Methods: Informed by action research the project conducted two cycles of planning, action, evaluation and reflection. Four key pedagogical principles informed the re-design of the assessment and feedback practices. Evaluation activities included document analysis, interviews with staff (n = 10) and students (n = 7), and student questionnaires (n = 54). Descriptive statistics were used to analyse the questionnaire data. Framework thematic analysis was used to develop themes across the interview data.Results: InterACT was reported by students and staff to promote self-evaluation, engagement with feedback and feedback dialogue. Streamlining the process after the first cycle of action research was crucial for improving engagement of students and staff. The interACT process of promoting self-evaluation, reflection on feedback, feedback dialogue and longitudinal perspectives of feedback has clear benefits and should be transferable to other contexts.Conclusions: InterACT has involved comprehensive re-engineering of the assessment and feedback processes using educational principles to guide the design taking into account stakeholder perspectives. These principles and the strategies to enact them should be transferable to other contexts

    Categories of insight and their correlates: An exploration of relationships among classic-type insight problems, rebus puzzles, remote associates and esoteric analogies.

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    A central question in creativity concerns how insightful ideas emerge. Anecdotal examples of insightful scientific and technical discoveries include Goodyear's discovery of the vulcanization of rubber, and Mendeleev's realization that there may be gaps as he tried to arrange the elements into the Periodic Table. Although most people would regard these discoveries as insightful, cognitive psychologists have had difficulty in agreeing on whether such ideas resulted from insights or from conventional problem solving processes. One area of wide agreement among psychologists is that insight involves a process of restructuring. If this view is correct, then understanding insight and its role in problem solving will depend on a better understanding of restructuring and the characteristics that describe it. This article proposes and tests a preliminary classification of insight problems based on several restructuring characteristics: the need to redefine spatial assumptions, the need to change defined forms, the degree of misdirection involved, the difficulty in visualizing a possible solution, the number of restructuring sequences in the problem, and the requirement for figure-ground type reversals. A second purpose of the study was to compare performance on classic spatial insight problems with two types of verbal tests that may be related to insight, the Remote Associates Test (RAT), and rebus puzzles. In doing so, we report on the results of a survey of 172 business students at the University of Waikato in New Zealand who completed classic-type insight, RAT and rebus problems

    Phase diagram of a generalized ABC model on the interval

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    We study the equilibrium phase diagram of a generalized ABC model on an interval of the one-dimensional lattice: each site i=1,...,Ni=1,...,N is occupied by a particle of type \a=A,B,C, with the average density of each particle species N_\a/N=r_\a fixed. These particles interact via a mean field non-reflection-symmetric pair interaction. The interaction need not be invariant under cyclic permutation of the particle species as in the standard ABC model studied earlier. We prove in some cases and conjecture in others that the scaled infinite system N\rw\infty, i/N\rw x\in[0,1] has a unique density profile \p_\a(x) except for some special values of the r_\a for which the system undergoes a second order phase transition from a uniform to a nonuniform periodic profile at a critical temperature Tc=3rArBrC/2πT_c=3\sqrt{r_A r_B r_C}/2\pi.Comment: 25 pages, 6 figure

    Transistor screening evaluation SJ6708H

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    A manufacturer was contracted to screen 125 transistors capable of withstanding the high level inductive voltages obtained when switching inductive loads. Planned differences included a change in die bonding to comply with NASA's desire for hard solder die attachment which further necessitated a change in package to conform to the required die mounting system. Evaluation of the electrical performance and recommended changes were made during the preliminary build phase of the program. The following sections are outlined: (1) narrative outline; (2) customer data summary and X-ray reports; (3) device specification; (4) failure analysis reports; (5) test facilities list; and (6) test measurement data
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