5,396 research outputs found
Evaluation of a wind-tunnel gust response technique including correlations with analytical and flight test results
A wind tunnel technique for obtaining gust frequency response functions for use in predicting the response of flexible aircraft to atmospheric turbulence is evaluated. The tunnel test results for a dynamically scaled cable supported aeroelastic model are compared with analytical and flight data. The wind tunnel technique, which employs oscillating vanes in the tunnel throat section to generate a sinusoidally varying flow field around the model, was evaluated by use of a 1/30 scale model of the B-52E airplane. Correlation between the wind tunnel results, flight test results, and analytical predictions for response in the short period and wing first elastic modes of motion are presented
Visual responses in the lateral geniculate evoked by Cx36-independent rod pathways
AbstractEmerging evidence indicates rods can communicate with retinal ganglion cells (RGCs) via pathways that do not involve gap-junctions. Here we investigated the significance of such pathways for central visual responses, using mice lacking a key gap junction protein (Cx36−/−) and carrying a mutation that disrupts cone phototransduction (Gnat2cpfl3). Electrophysiological recordings spanning the lateral geniculate revealed rod-mediated ON and OFF visual responses in virtually every cell from all major anatomical sub-compartments of this nucleus. Hence, we demonstrate that one or more classes of RGC receive input from Cx36-independent rod pathways and drive extensive ON and OFF responses across the visual thalamus
The ROTSE-III Robotic Telescope System
The observation of a prompt optical flash from GRB990123 convincingly
demonstrated the value of autonomous robotic telescope systems. Pursuing a
program of rapid follow-up observations of gamma-ray bursts, the Robotic
Optical Transient Search Experiment (ROTSE) has developed a next-generation
instrument, ROTSE-III, that will continue the search for fast optical
transients. The entire system was designed as an economical robotic facility to
be installed at remote sites throughout the world. There are seven major system
components: optics, optical tube assembly, CCD camera, telescope mount,
enclosure, environmental sensing & protection and data acquisition. Each is
described in turn in the hope that the techniques developed here will be useful
in similar contexts elsewhere.Comment: 19 pages, including 4 figures. To be published in PASP in January,
2003. PASP Number IP02-11
Towards an analytical framework of science communication models
This chapter reviews the discussion in science communication circles of models for public communication of science and technology (PCST). It questions the claim that there has been a large-scale shift from a ‘deficit model’ of communication to a ‘dialogue model’, and it demonstrates the survival of the deficit model along with the ambiguities of that model. Similar discussions in related fields of communication, including the critique of dialogue, are briefly sketched. Outlining the complex circumstances governing approaches to PCST, the author argues that communications models often perceived to be opposed can, in fact, coexist when the choices are made explicit. To aid this process, the author proposes an analytical framework of communication models based on deficit, dialogue and participation, including variations on each
Risk Stratification in Women Enrolled in the Acute Decompensated Heart Failure National Registry Emergency Module (ADHERE-EM)
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75587/1/j.1553-2712.2008.00030.x.pd
Relationship between quantum decoherence times and solvation dynamics in condensed phase chemical systems
A relationship between the time scales of quantum coherence loss and
short-time solvent response for a solute/bath system is derived for a Gaussian
wave packet approximation for the bath. Decoherence and solvent response times
are shown to be directly proportional to each other, with the proportionality
coefficient given by the ratio of the thermal energy fluctuations to the
fluctuations in the system-bath coupling. The relationship allows the
prediction of decoherence times for condensed phase chemical systems from well
developed experimental methods.Comment: 10 pages, no figures, late
A Pair of Compact Red Galaxies at Redshift 2.38, Immersed in a 100 kpc Scale Ly-alpha Nebula
We present Hubble Space Telescope (HST) and ground-based observations of a
pair of galaxies at redshift 2.38, which are collectively known as 2142-4420 B1
(Francis et al. 1996). The two galaxies are both luminous extremely red objects
(EROs), separated by 0.8 arcsec. They are embedded within a 100 kpc scale
diffuse Ly-alpha nebula (or blob) of luminosity ~10^44 erg/s.
The radial profiles and colors of both red objects are most naturally
explained if they are young elliptical galaxies: the most distant yet found. It
is not, however, possible to rule out a model in which they are abnormally
compact, extremely dusty starbursting disk galaxies. If they are elliptical
galaxies, their stellar populations have inferred masses of ~10^11 solar masses
and ages of ~7x10^8 years. Both galaxies have color gradients: their centers
are significantly bluer than their outer regions. The surface brightness of
both galaxies is roughly an order of magnitude greater than would be predicted
by the Kormendy relation. A chain of diffuse star formation extending 1 arcsec
from the galaxies may be evidence that they are interacting or merging.
The Ly-alpha nebula surrounding the galaxies shows apparent velocity
substructure of amplitude ~ 700 km/s. We propose that the Ly-alpha emission
from this nebula may be produced by fast shocks, powered either by a galactic
superwind or by the release of gravitational potential energy.Comment: 33 pages, 9 figures, ApJ in press (to appear in Jun 10 issue
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