22,173 research outputs found
The Reality and Measurement of the Wavefunction
Using a simple version of the model for the quantum measurement of a two
level system, the contention of Aharonov, Anandan, and Vaidman that one must in
certain circumstances give the wavefunction an ontological as well as an
epistemological significance is examined. I decide that their argument that the
wave function of a system can be measured on a single system fails to establish
the key point and that what they demonstrate is the ontological significance of
certain operators in the theory, with the wave function playing its usual
epistemological role.Comment: 10p
Wing surface-jet interaction characteristics of an upper-surface blown model with rectangular exhaust nozzles and a radius flap
The wing surface jet interaction characteristics of an upper surface blown transport configuration were investigated in the Langley V/STOL tunnel. Velocity profiles at the inboard engine center line were measured for several chordwise locations, and chordwise pressure distributions on the flap were obtained. The model represented a four engine arrangement having relatively high aspect ratio rectangular spread, exhaust nozzles and a simple trailing edge radius flap
Is Socrates Dead? Can Socratic Teachers in Higher Education Remain Alive?
The contentions of this paper are quite simple: Socrates has long been dead. Tragically, the teacher in higher education who attempts to emulate him is unlikely to remain alive. Moreover, there are a number of poisonous elements within the higher education environment that are potentially lethal to the Socratic teacher of today. Citations from Apology, Crito, Ion, Meno, Phaedo, Symposium, and The Republic support the above contentions
On the Evidence for Axion-like Particles from Active Galactic Nuclei
Burrage, Davis, and Shaw recently suggested exploiting the correlations
between high and low energy luminosities of astrophysical objects to probe
possible mixing between photons and axion-like particles (ALP) in magnetic
field regions. They also presented evidence for the existence of ALP's by
analyzing the optical/UV and X-ray monochromatic luminosities of AGNs. We
extend their work by using the monochromatic luminosities of 320 unobscured
Active Galactic Nuclei from the Sloan Digital Sky Survey/Xmm-Newton Quasar
Survey (Young et al., 2009), which allows the exploration of 18 different
combinations of optical/UV and X-ray monochromatic luminosities. However, we do
not find compelling evidence for the existence of ALPs. Moreover, it appears
that the signal reported by Burrage et al. is more likely due to X-ray
absorption rather than to photon-ALP oscillation.Comment: 16 pages, 12 figures. Updated to reflect the minor changes introduced
in the published versio
Differential effects of Alzheimer\u27s disease and Huntington\u27s disease on the performance of mental rotation
he ability to spatially rotate a mental image was compared in patients with Alzheimer\u27s disease (AD; n = 18) and patients with Huntington\u27s disease (HD; n = 18). Compared to their respective age-matched normal control (NC) group, the speed, but not the accuracy, of mental rotation abnormally decreased with increasing angle of orientation for patients with HD. In contrast, the accuracy, but not the speed, of rotation abnormally decreased with increasing angle of orientation for patients with AD. Additional analyses showed that these unique patterns of performance were not attributable to different speed/accuracy trade-off sensitivities. This double dissociation suggests that the distinct brain regions affected in the two diseases differentially contribute to speed and accuracy of mental rotation. Specifically, the slowing exhibited by HD patients may be mediated by damage to the basal ganglia, whereas the spatial manipulation deficit of AD patients may reflect pathology in parietal and temporal lobe association cortices important for visuospatial processing. (JINS, 2005, 11, 30–39.
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