3,966 research outputs found
An Alternative to Spinning Dust for the Microwave Emission of LPH 201.663+1.643: an Ultracompact HII Region
The microwave spectral energy distribution of the dusty, diffuse H II region
LPH 201.663+1.643 has been interpreted by others as tentative evidence for
microwave emission from spinning dust grains. We present an alternative
interpretation for that particular object; specifically, that an ultracompact H
II region embedded within the dust cloud would explain the available
observations as well or better than spinning dust. Parameters for the size,
surface brightness, and flux density of the putative ultracompact HII region,
derived from the microwave observations, are within known ranges. A possible
candidate for such an ultracompact H II region is IRAS 06337+1051, based upon
its infrared colors. However, IRAS 06337+1051's infrared flux appears to be too
small to be consistent with the microwave flux required for this alternative
model to explain the observations.Comment: 11 pages, 3 figures, accepted to ApJ Letter
Detecting Life-bearing Extra-solar Planets with Space Telescopes
One of the promising methods to search for life on extra-solar planets
(exoplanets) is to detect life's signatures in their atmospheres. Spectra of
exoplanet atmospheres at the modest resolution needed to search for oxygen,
carbon dioxide, water, and methane will demand large collecting areas and large
diameters to capture and isolate the light from planets in the habitable zones
around the stars. For telescopes using coronagraphs to isolate the light from
the planet, each doubling of telescope diameter will increase the available
sample of stars by an order of magnitude, indicating a high scientific return
if the technical difficulties of constructing very large space telescopes can
be overcome. For telescopes detecting atmospheric signatures of transiting
planets, the sample size increases only linearly with diameter, and the
available samples are probably too small to guarantee detection of life-bearing
planets. Using samples of nearby stars suitable for exoplanet searches, this
paper shows that the demands of searching for life with either technique will
require large telescopes, with diameters of order 10m or larger in space.Comment: 15 pages, 6 figures, submitted to Ap.
Use of in vitro and haptic assessments in the characterisation of surface lubricity
Lubricity is a key property of hydrophilic-coated urinary catheter surfaces. In vitro tests are commonly employed for evaluation of surface properties in the development of novel catheter coating technologies, however, their value in predicting the more subjective feeling of lubricity requires validation. We herein perform a range of in vitro assessments and human organoleptic studies to characterise surface properties of developmental hydrophilic coating formulations, including water wettability, coefficient of friction, dry-out kinetics and lubricity. Significant reductions of up to 40% in the contact angles and coefficient of friction values of the novel coating formulations in comparison to the control poly(vinyl pyrrolidone)-coated surfaces were demonstrated during quantitative laboratory assessments. In contrast, no significant differences in the more subjective feeling of lubricity between the novel formulations and the control-coated surfaces were observed when formulations were haptically assessed by the techniques described herein. This study, importantly, highlights the need for optimisation of in vitro and human haptic assessments to more reliably predict patient preferences
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