656 research outputs found
“Trying, But Failing” : The Role of Inhaler Technique and Mode of Delivery in Respiratory Medication Adherence
Recognition of Commercial Support: The Expert Adherence Panel Meeting from which the concepts presented in this article were first discussed and the manuscript submission costs were supported by the Respiratory Effectiveness Group.Peer reviewedPublisher PD
Near-infrared transit photometry of the exoplanet HD 149026b
The transiting exoplanet HD 149026b is an important case for theories of
planet formation and planetary structure, because the planet's relatively small
size has been interpreted as evidence for a highly metal-enriched composition.
We present observations of 4 transits with the Near Infrared Camera and
Multi-Object Spectrometer on the Hubble Space Telescope, within a wavelength
range of 1.1--2.0 m. Analysis of the light curve gives the most precise
estimate yet of the stellar mean density, g cm. By requiring agreement between the
observed stellar properties (including ) and stellar evolutionary
models, we refine the estimate of the stellar radius: R_\sun. We also find a deeper transit than has been
measured at optical and mid-infrared wavelengths. Taken together, these
findings imply a planetary radius of , which is larger than earlier estimates. Models of the planetary interior
still require a metal-enriched composition, although the required degree of
metal enrichment is reduced. It is also possible that the deeper NICMOS transit
is caused by wavelength-dependent absorption by constituents in the planet's
atmosphere, although simple model atmospheres do not predict this effect to be
strong enough to account for the discrepancy. We use the 4 newly-measured
transit times to compute a refined transit ephemeris.Comment: 18 pages, 13 figures, accepted for publication in Ap
Knowledge-based patient screening for rare and emerging infectious/parasitic diseases: a case study of brucellosis and murine typhus.
Many infectious and parasitic diseases, especially those newly emerging or reemerging, present a difficult diagnostic challenge because of their obscurity and low incidence. Important clues that could lead to an initial diagnosis are often overlooked, misinterpreted, not linked to a disease, or disregarded. We constructed a computer-based decision support system containing 223 infectious and parasitic diseases and used it to conduct a historical intervention study based on field investigation records of 200 cases of human brucellosis and 96 cases of murine typhus that occurred in Texas from 1980 through 1989. Knowledge-based screening showed that the average number of days from the initial patient visit to the time of correct diagnosis was significantly reduced (brucellosis-from 17.9 to 4.5 days, p = 0.0001, murine typhus-from 11.5 to 8.6 days, p = 0.001). This study demonstrates the potential value of knowledge-based patient screening for rare infectious and parasitic diseases
Gram-Negative Bacterial Infection in Thigh Abscess Can Migrate to Distant Burn Depending on Burn Depth
Sepsis remains the major cause of death in patients with major burn injuries. In the present investigation we evaluated the interaction between burn injuries of varying severity and preexisting distant infection. We used Gram-negative bacteria (Pseudomonas aeruginosa and Proteus mirabilis) that were genetically engineered to be bioluminescent, which allowed for noninvasive, sequential optical imaging of the extent and severity of the infection. The bioluminescent bacteria migrated from subcutaneous abscesses in the leg to distant burn wounds on the back depending on the severity of the burn injury, and this migration led to increased mortality of the mice. Treatment with ciprofloxacin, injected either in the leg with the bacterial infection or into the burn eschar, prevented this colonization of the wound and decreased mortality. The present data suggest that burn wounds can readily become colonized by infections distant from the wound itself
NICMOS Observations of the Transiting Hot Jupiter XO-1b
We refine the physical parameters of the transiting hot Jupiter planet XO-1b
and its stellar host XO-1 using HST NICMOS observations. XO-1b has a radius
Rp=1.21+/-0.03 RJup, and XO-1 has a radius Rs=0.94+/-0.02 RSun, where the
uncertainty in the mass of XO-1 dominates the uncertainty of Rp and Rs. There
are no significant differences in the XO-1 system properties between these
broad-band NIR observations and previous determinations based upon ground-based
optical observations. We measure two transit timings from these observations
with 9 s and 15 s precision. As a residual to a linear ephemeris model, there
is a 2.0 sigma timing difference between the two HST visits that are separated
by 3 transit events (11.8 days). These two transit timings and additional
timings from the literature are sufficient to rule out the presence of an Earth
mass planet orbiting in 2:1 mean motion resonance coplanar with XO-1b. We
identify and correct for poorly understood gain-like variations present in
NICMOS time series data. This correction reduces the effective noise in time
series photometry by a factor of two, for the case of XO-1.Comment: 13 pages, 8 figures, submitted to Ap
Precise Estimates of the Physical Parameters for the Exoplanet System HD-17156 Enabled by HST FGS Transit and Asteroseismic Observations
We present observations of three distinct transits of HD 17156b obtained with
the Fine Guidance Sensors (FGS) on board the Hubble Space Telescope} (HST). We
analyzed both the transit photometry and previously published radial velocities
to find the planet-star radius ratio R_p/R_s = 0.07454 +/- 0.00035, inclination
i=86.49 +0.24/-0.20 deg, and scaled semi-major axis a/R = 23.19 +0.32/-0.27.
This last value translates directly to a mean stellar density determination of
0.522 +0.021/-0.018 g cm^-3. Analysis of asteroseismology observations by the
companion paper of Gilliland et al. (2009) provides a consistent but
significantly refined measurement of the stellar mean density. We compare
stellar isochrones to this density estimate and find M_s = 1.275 +/- 0.018
M_sun and a stellar age of $3.37 +0.20/-0.47 Gyr. Using this estimate of M_s
and incorporating the density constraint from asteroseismology, we model both
the photometry and published radial velocities to estimate the planet radius
R_p= 1.0870 +/- 0.0066 Jupiter radii and the stellar radius R_s = 1.5007 +/-
0.0076 R_sun. The planet radius is larger than that found in previous studies
and consistent with theoretical models of a solar-composition gas giant of the
same mass and equilibrium temperature. For the three transits, we determine the
times of mid-transit to a precision of 6.2 s, 7.6 s, and 6.9 s, and the transit
times for HD 17156 do not show any significant departures from a constant
period. The joint analysis of transit photometry and asteroseismology presages
similar studies that will be enabled by the NASA Kepler Mission.Comment: Accepted for publication to Ap
The Transit Ingress and the Tilted Orbit of the Extraordinarily Eccentric Exoplanet HD 80606b
We present the results of a transcontinental campaign to observe the 2009
June 5 transit of the exoplanet HD 80606b. We report the first detection of the
transit ingress, revealing the transit duration to be 11.64 +/- 0.25 hr and
allowing more robust determinations of the system parameters. Keck spectra
obtained at midtransit exhibit an anomalous blueshift, giving definitive
evidence that the stellar spin axis and planetary orbital axis are misaligned.
The Keck data show that the projected spin-orbit angle is between 32-87 deg
with 68.3% confidence and between 14-142 deg with 99.73% confidence. Thus the
orbit of this planet is not only highly eccentric (e=0.93), but is also tilted
away from the equatorial plane of its parent star. A large tilt had been
predicted, based on the idea that the planet's eccentric orbit was caused by
the Kozai mechanism. Independently of the theory, it is noteworthy that all 3
exoplanetary systems with known spin-orbit misalignments have massive planets
on eccentric orbits, suggesting that those systems migrate differently than
lower-mass planets on circular orbits.Comment: ApJ, in press [13 pg
Validation of Kepler's Multiple Planet Candidates. III: Light Curve Analysis & Announcement of Hundreds of New Multi-planet Systems
The Kepler mission has discovered over 2500 exoplanet candidates in the first
two years of spacecraft data, with approximately 40% of them in candidate
multi-planet systems. The high rate of multiplicity combined with the low rate
of identified false-positives indicates that the multiplanet systems contain
very few false-positive signals due to other systems not gravitationally bound
to the target star (Lissauer, J. J., et al., 2012, ApJ 750, 131). False
positives in the multi- planet systems are identified and removed, leaving
behind a residual population of candidate multi-planet transiting systems
expected to have a false-positive rate less than 1%. We present a sample of 340
planetary systems that contain 851 planets that are validated to substantially
better than the 99% confidence level; the vast majority of these have not been
previously verified as planets. We expect ~2 unidentified false-positives
making our sample of planet very reliable. We present fundamental planetary
properties of our sample based on a comprehensive analysis of Kepler light
curves and ground-based spectroscopy and high-resolution imaging. Since we do
not require spectroscopy or high-resolution imaging for validation, some of our
derived parameters for a planetary system may be systematically incorrect due
to dilution from light due to additional stars in the photometric aperture.
None the less, our result nearly doubles the number of verified exoplanets.Comment: 138 pages, 8 Figures, 5 Tables. Accepted for publications in the
Astrophysical Journa
Glaucoma in primates: cytochrome oxidase reactivity in parvo- and magnocellular
PURPOSE. To evaluate the differential effects of ganglion cell depletion from experimental glaucoma on the relative metabolic activities of neurons in the parvo (P)-and magno (M)-cellular visual pathways of the macaque visual system. METHODS. Monocular experimental glaucoma was induced in monkeys (Macaca mulatta and M. fascicularis) by applying a laser to the trabecular meshwork to increase intraocular pressure (IOP). After other behavioral and electrophysiological studies, the lateral geniculate nuclei (LGNs) and the primary visual cortices were analyzed for functional afference from surviving ganglion cells, indicated by cytochrome oxidase (CO) histochemistry. RESULTS. CO reactivity (COR) indicated a general reduction in neural metabolism with increasing severity of glaucoma. COR in the LGNs was reduced to the same degree in both the P-and M-cellular layers. In layer 4C of the V1 cortex, the reactivity was always reduced more than in the layer 4C␣ division. CONCLUSIONS. Experimental glaucoma in monkeys reduces visual afference to the central nervous system, thereby reducing the metabolic drive as indicated by COR. The detrimental effect of glaucoma did not appear to be any greater for the M-cell, rather than the P-cell pathway in the LGN or in the visual cortex. Both are affected by the duration and severity of the experimental glaucoma. Overall, the alterations in metabolism of neurons in the parallel visual pathways supplied by the P␣ and P ganglion cells do not suggest that tests based on the functional properties of one or the other would provide optimal assessment of glaucoma. (Invest Ophthalmol Vis Sci. 2000;41: 1791-180
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