137 research outputs found
A model for in situ plan of care for a critically unstable pediatric patient following I‐131 MIBG infusion
Recent clinical trials have moved iodine‐131 (I‐131) metaiodobenzylguanidine (MIBG) therapy into frontline management of high‐risk neuroblastoma. With this expansion, it is reasonable to anticipate the need for intensive care level resuscitations. Radiation exposure remains the greatest risk to health care professionals managing these patients. We combined shock simulation scenario data with actual radiation dosimetry data to create a care model allowing for aggressive, prolonged in situ resuscitation of a critically ill pediatric patient after I‐131 MIBG administration. This model will maintain a critical care provider’s radiation level below 10% of the annual occupational dose limit (5 mSv, 500 mrem) per patient managed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/162761/2/pbc28665.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/162761/1/pbc28665_am.pd
Trains in crosswinds – comparison of full-scale on-train measurements, physical model tests and CFD calculations
In this paper a major series of experiments is described that included extensive full-scale measurements of cross wind induced pressures on the Class 43 New Measurement Train over an extended 21 month period, together with wind tunnel, moving model tests and CFD calculations, and allows, for the first time, a proper evaluation of the adequacy of these techniques. Static wind tunnel tests and moving model tests show good agreement with each other, both in terms of the measured pressure field around the train and in the overall side force per unit length over the yaw angle range from 15 to 30°. Similarly the wind tunnel tests and the CFD calculations show good agreement with each other for yaw angles up to 15°. Two different analyses of the full-scale data were carried out - an analysis of 1 s average wind speeds and forces, and an analysis of specific gusts. There was a very great deal of scatter in the results and only the results from simple track topographies were found to agree well with the model and computational results
The Demographics and Atmospheres of Giant Planets with the ELTs
Gas giants are the most readily detectable exoplanets but fundamental
questions about their system architectures, formation, migration, and
atmospheres have been unanswerable with the current generation of ground- and
space-based facilities. The dominant techniques to detect and characterize
giant planets radial velocities, transits, direct imaging, microlensing,
and astrometry are each isolated to a limited range of planet masses,
separations, ages, and temperatures. These windows into the arrangement and
physical properties of giant planets have spawned new questions about the
timescale and location of their assembly; the distributions of planet mass and
orbital separation at young and old ages; the composition and structure of
their atmospheres; and their orbital and rotational angular momentum
architectures. The ELTs will address these questions by building bridges
between these islands of mass, orbital distance, and age. The angular
resolution, collecting area, all-sky coverage, and novel instrumentation suite
of these facilities are needed to provide a complete map of the orbits and
atmospheric evolution of gas giant planets (0.310 ) across
space (0.1100 AU) and time (1 Myr to 10 Gyr). This white paper highlights
the scientific potential of the GMT and TMT to address these outstanding
questions, with a particular focus on the role of direct imaging and
spectroscopy of large samples of giant planets that will soon be made available
with .Comment: White paper for the Astro2020 decadal surve
The effect of distance on reaction time in aiming movements
Target distance affects movement duration in aiming tasks but its effect on reaction time (RT) is poorly documented. RT is a function of both preparation and initiation. Experiment 1 pre-cued movement (allowing advanced preparation) and found no influence of distance on RT. Thus, target distance does not affect initiation time. Experiment 2 removed pre-cue information and found that preparing a movement of increased distance lengthens RT. Experiment 3 explored movements to targets of cued size at non-cued distances and found size altered peak speed and movement duration but RT was influenced by distance alone. Thus, amplitude influences preparation time (for reasons other than altered duration) but not initiation time. We hypothesise that the RT distance effect might be due to the increased number of possible trajectories associated with further targets: a hypothesis that can be tested in future experiments
EarthFinder Probe Mission Concept Study: Characterizing nearby stellar exoplanet systems with Earth-mass analogs for future direct imaging
EarthFinder is a NASA Astrophysics Probe mission concept selected for study
as input to the 2020 Astrophysics National Academies Decadal Survey. The
EarthFinder concept is based on a dramatic shift in our understanding of how
PRV measurements should be made. We propose a new paradigm which brings the
high precision, high cadence domain of transit photometry as demonstrated by
Kepler and TESS to the challenges of PRV measurements at the cm/s level. This
new paradigm takes advantage of: 1) broad wavelength coverage from the UV to
NIR which is only possible from space to minimize the effects of stellar
activity; 2) extremely compact, highly stable, highly efficient spectrometers
(R>150,000) which require the diffraction-limited imaging possible only from
space over a broad wavelength range; 3) the revolution in laser-based
wavelength standards to ensure cm/s precision over many years; 4) a high
cadence observing program which minimizes sampling-induced period aliases; 5)
exploiting the absolute flux stability from space for continuum normalization
for unprecedented line-by-line analysis not possible from the ground; and 6)
focusing on the bright stars which will be the targets of future imaging
missions so that EarthFinder can use a ~1.5 m telescope.Comment: NASA Probe Mission concept white paper for 2020 Astrophysics National
Academies Decadal Surve
EarthFinder Probe Mission Concept Study: Characterizing nearby stellar exoplanet systems with Earth-mass analogs for future direct imaging
EarthFinder is a NASA Astrophysics Probe mission concept selected for study as input to the 2020 Astrophysics National Academies Decadal Survey. The EarthFinder concept is based on a dramatic shift in our understanding of how PRV measurements should be made. We propose a new paradigm which brings the high precision, high cadence domain of transit photometry as demonstrated by Kepler and TESS to the challenges of PRV measurements at the cm/s level. This new paradigm takes advantage of: 1) broad wavelength coverage from the UV to NIR which is only possible from space to minimize the effects of stellar activity; 2) extremely compact, highly stable, highly efficient spectrometers (R>150,000) which require the diffraction-limited imaging possible only from space over a broad wavelength range; 3) the revolution in laser-based wavelength standards to ensure cm/s precision over many years; 4) a high cadence observing program which minimizes sampling-induced period aliases; 5) exploiting the absolute flux stability from space for continuum normalization for unprecedented line-by-line analysis not possible from the ground; and 6) focusing on the bright stars which will be the targets of future imaging missions so that EarthFinder can use a ~1.5 m telescope
Masses, radii, and orbits of small Kepler planets : The transition from gaseous to rocky planets
We report on the masses, sizes, and orbits of the planets orbiting 22 Kepler stars. There are 49 planet candidates around these stars, including 42 detected through transits and 7 revealed by precise Doppler measurements of the host stars. Based on an analysis of the Kepler brightness measurements, along with high-resolution imaging and spectroscopy, Doppler spectroscopy, and (for 11 stars) asteroseismology, we establish low false-positive probabilities (FPPs) for all of the transiting planets (41 of 42 have an FPP under 1%), and we constrain their sizes and masses. Most of the transiting planets are smaller than three times the size of Earth. For 16 planets, the Doppler signal was securely detected, providing a direct measurement of the planet's mass. For the other 26 planets we provide either marginal mass measurements or upper limits to their masses and densities; in many cases we can rule out a rocky composition. We identify six planets with densities above 5 g cm-3, suggesting a mostly rocky interior for them. Indeed, the only planets that are compatible with a purely rocky composition are smaller than 2 R ⊕. Larger planets evidently contain a larger fraction of low-density material (H, He, and H2O).Peer reviewedFinal Accepted Versio
The Community Land Model version 5 : description of new features, benchmarking, and impact of forcing uncertainty
The Community Land Model (CLM) is the land component of the Community Earth System Model (CESM) and is used in several global and regional modeling systems. In this paper, we introduce model developments included in CLM version 5 (CLM5), which is the default land component for CESM2. We assess an ensemble of simulations, including prescribed and prognostic vegetation state, multiple forcing data sets, and CLM4, CLM4.5, and CLM5, against a range of metrics including from the International Land Model Benchmarking (ILAMBv2) package. CLM5 includes new and updated processes and parameterizations: (1) dynamic land units, (2) updated parameterizations and structure for hydrology and snow (spatially explicit soil depth, dry surface layer, revised groundwater scheme, revised canopy interception and canopy snow processes, updated fresh snow density, simple firn model, and Model for Scale Adaptive River Transport), (3) plant hydraulics and hydraulic redistribution, (4) revised nitrogen cycling (flexible leaf stoichiometry, leaf N optimization for photosynthesis, and carbon costs for plant nitrogen uptake), (5) global crop model with six crop types and time‐evolving irrigated areas and fertilization rates, (6) updated urban building energy, (7) carbon isotopes, and (8) updated stomatal physiology. New optional features include demographically structured dynamic vegetation model (Functionally Assembled Terrestrial Ecosystem Simulator), ozone damage to plants, and fire trace gas emissions coupling to the atmosphere. Conclusive establishment of improvement or degradation of individual variables or metrics is challenged by forcing uncertainty, parametric uncertainty, and model structural complexity, but the multivariate metrics presented here suggest a general broad improvement from CLM4 to CLM5
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