195 research outputs found
WISE/NEOWISE Observations of Comet 103P/Hartley 2
We report results based on mid-infrared photometry of comet 103P/Hartley 2 taken during 2010 May 4-13 (when the comet was at a heliocentric distance of 2.3 AU, and an observer distance of 2.0 AU) by the Wide-field Infrared Survey Explorer. Photometry of the coma at 22 ÎŒm and data from the University of Hawaii 2.2 m telescope obtained on 2010 May 22 provide constraints on the dust particle size distribution, d log n/d log m, yielding power-law slope values of alpha = â0.97 ± 0.10, steeper than that found for the inbound particle fluence during the Stardust encounter of comet 81P/Wild 2. The extracted nucleus signal at 12 ÎŒm is consistent with a body of average spherical radius of 0.6 ± 0.2 km (one standard deviation), assuming a beaming parameter of 1.2. The 4.6 ÎŒm band signal in excess of dust and nucleus reflected and thermal contributions may be attributed to carbon monoxide or carbon dioxide emission lines and provides limits and estimates of species production. Derived carbon dioxide coma production rates are 3.5(± 0.9) Ă 10^(24) molecules per second. Analyses of the trail signal present in the stacked image with an effective exposure time of 158.4 s yields optical-depth values near 9 Ă 10^(â10) at a delta mean anomaly of 0.2 deg trailing the comet nucleus, in both 12 and 22 ÎŒm bands. A minimum chi-squared analysis of the dust trail position yields a beta-parameter value of 1.0 Ă 10^(â4), consistent with a derived mean trail-grain diameter of 1.1/Ï cm for grains of Ï g cm^(â3) density. This leads to a total detected trail mass of at least 4 Ă 10^(10) Ï kg
The Grizzly, November 12, 2015
Highlighting a New Trend on Campus âą Making Connections: Ursinus Prepares to Break Ground on a Structure Between Pfahler and Thomas âą Acclaimed Literary Critic to Give Talk on Campus âą Ursinus Brings Top Lawyer Aboard in New Position âą International Perspective: How One Student Uses Dance to Connect Ethiopia and Ursinus âą Can You Really Netflix and Chill Without Killing Your Grades? âą Opinions: Are You a White Feminist?; Bridge of Spies âą Defensive Lineman Unleashes Passion for Music âą Field Hockey Upsets F&M for Titlehttps://digitalcommons.ursinus.edu/grizzlynews/1677/thumbnail.jp
The Mass Distribution of Starless and Protostellar Cores in Gould Belt Clouds
Using data from the SCUBA Legacy Catalogue (850 ÎŒm) and Spitzer Space Telescope (3.6-70 ÎŒm), we explore dense cores in the Ophiuchus, Taurus, Perseus, Serpens, and Orion molecular clouds. We develop a new method to discriminate submillimeter cores found by Submillimeter Common-User Bolometer Array (SCUBA) as starless or protostellar, using point source photometry from Spitzer wide field surveys. First, we identify infrared sources with red colors associated with embedded young stellar objects (YSOs). Second, we compare the positions of these YSO candidates to our submillimeter cores. With these identifications, we construct new, self-consistent starless and protostellar core mass functions (CMFs) for the five clouds. We find best-fit slopes to the high-mass end of the CMFs of â1.26 ± 0.20, â1.22 ± 0.06, â0.95 ± 0.20, and â1.67 ± 0.72 for Ophiuchus, Taurus, Perseus, and Orion, respectively. Broadly, these slopes are each consistent with the â1.35 power-law slope of the Salpeter initial mass function at higher masses, but suggest some differences. We examine a variety of trends between these CMF shapes and their parent cloud properties, potentially finding a correlation between the high-mass slope and core temperature. We also find a trend between core mass and effective size, but we are very limited by sensitivity. We make similar comparisons between core mass and size with visual extinction (for A_V â„ 3) and find no obvious trends. We also predict the numbers and mass distributions of cores that future surveys with SCUBA-2 may detect in each of these clouds
WISE/NEOWISE observations of Active Bodies in the Main Belt
We report results based on mid-infrared photometry of 5 active main belt
objects (AMBOs) detected by the Wide-field Infrared Survey Explorer (WISE)
spacecraft. Four of these bodies, P/2010 R2 (La Sagra), 133P/Elst-Pizarro,
(596) Scheila, and 176P/LINEAR, showed no signs of activity at the time of the
observations, allowing the WISE detections to place firm constraints on their
diameters and albedos. Geometric albedos were in the range of a few percent,
and on the order of other measured comet nuclei. P/2010 A2 was observed on
April 2-3, 2010, three months after its peak activity. Photometry of the coma
at 12 and 22 {\mu}m combined with ground-based visible-wavelength measurements
provides constraints on the dust particle mass distribution (PMD), dlogn/dlogm,
yielding power-law slope values of {\alpha} = -0.5 +/- 0.1. This PMD is
considerably more shallow than that found for other comets, in particular
inbound particle fluence during the Stardust encounter of comet 81P/Wild 2. It
is similar to the PMD seen for 9P/Tempel 1 in the immediate aftermath of the
Deep Impact experiment. Upper limits for CO2 & CO production are also provided
for each AMBO and compared with revised production numbers for WISE
observations of 103P/Hartley 2.Comment: 32 Pages, including 5 Figure
Recommended from our members
Bias Blind Spot: Structure, Measurement, and Consequences
People exhibit a bias blind spot: they are less likely to detect bias in themselves than in others. We report the development and validation of an instrument to measure individual differences in the propensity to exhibit the bias blind spot that is unidimensional, internally consistent, has high test-retest reliability, and is discriminated from measures of intelligence, decision making ability, and personality traits related to self-esteem, self-enhancement, and self-presentation. The scale is predictive of the extent to which people judge their abilities to be better-than-average for easy tasks and worse-than-average for difficult tasks, ignore the advice of others, and are responsive to an intervention designed to mitigate a different judgmental bias. These results suggest that the bias blind spot is a distinct metabias resulting from naĂŻve realism rather than other forms of egocentric cognition, and has unique effects on judgment and behavior
Crosswalk study on blood collection-tube types for Alzheimer's disease biomarkers
Introduction: Blood-based Alzheimer's disease (AD) biomarkers show promise, but pre-analytical protocol differences may pose problems. We examined seven AD blood biomarkers (amyloid beta [ A ÎČ ] 42 , A ÎČ 40 , phosphorylated tau [ p - ta u 181 , total tau [t-tau], neurofilament light chain [NfL], A ÎČ 42 40 , and p - ta u 181 A ÎČ 42 ) in three collection tube types (ethylenediaminetetraacetic acid [EDTA] plasma, heparin plasma, serum). Methods: Plasma and serum were obtained from cerebrospinal fluid or amyloid positron emission tomography-positive and -negative participants (NÂ =Â 38) in the Wisconsin Registry for Alzheimer's Prevention. We modeled AD biomarker values observed in EDTA plasma versus heparin plasma and serum, and assessed correspondence with brain amyloidosis. Results: Results suggested bias due to tube type, but crosswalks are possible for some analytes, with excellent model fit for NfL ( R 2 =Â 0.94), adequate for amyloid ( R 2 =Â 0.40-0.69), and weaker for t-tau ( R 2 =Â 0.04-0.42) and p - ta u 181 ( R 2 =Â 0.22-0.29). Brain amyloidosis differentiated several measures, especially EDTA plasma pTa u 181 A ÎČ 42 ( d =Â 1.29). Discussion: AD biomarker concentrations vary by tube type. However, correlations for some biomarkers support harmonization across types, suggesting cautious optimism for use in banked blood
Nancy Grace Roman Space Telescope Coronagraph Instrument Observation Calibration Plan
NASA's next flagship mission, the Nancy Grace Roman Space Telescope, is a
2.4-meter observatory set to launch no later than May 2027. Roman features two
instruments: the Wide Field Imager and the Coronagraph Instrument. Roman's
Coronagraph is a Technology Demonstration that will push the current
capabilities of direct imaging to smaller contrast ratios (10) and
inner-working angles (3~/D). In order to achieve this high precision,
Roman Coronagraph data must be calibrated to remove as many potential sources
of error as possible. Here we present a detailed overview of the Nancy Grace
Roman Space Telescope Coronagraph Instrument Observation Calibration Plan
including identifying potential sources of error and how they will be mitigated
via on-sky calibrations.Comment: Posting for public information on the current status of the Roman
Coronagraph Observation Calibration Plan; latest updates as of July 29, 202
Development and Initial Validation of the PEG, a Three-item Scale Assessing Pain Intensity and Interference
Inadequate pain assessment is a barrier to appropriate pain management, but single-item âpain screeningâ provides limited information about chronic pain. Multidimensional pain measures such as the Brief Pain Inventory (BPI) are widely used in pain specialty and research settings, but are impractical for primary care. A brief and straightforward multidimensional pain measure could potentially improve initial assessment and follow-up of chronic pain in primary care.
To develop an ultra-brief pain measure derived from the BPI.
Development of a shortened three-item pain measure and initial assessment of its reliability, validity, and responsiveness.
We used data from 1) a longitudinal study of 500 primary care patients with chronic pain and 2) a cross-sectional study of 646 veterans recruited from ambulatory care.
Selected items assess average pain intensity (P), interference with enjoyment of life (E), and interference with general activity (G). Reliability of the three-item scale (PEG) was αâ=â0.73 and 0.89 in the two study samples. Overall, construct validity of the PEG was good for various pain-specific measures (râ=â0.60â0.89 in Study 1 and râ=â0.77â0.95 in Study 2), and comparable to that of the BPI. The PEG was sensitive to change and differentiated between patients with and without pain improvement at 6 months.
We provide strong initial evidence for reliability, construct validity, and responsiveness of the PEG among primary care and other ambulatory clinic patients. The PEG may be a practical and useful tool to improve assessment and monitoring of chronic pain in primary care
The Fifth Data Release of the Sloan Digital Sky Survey
This paper describes the Fifth Data Release (DR5) of the Sloan Digital Sky
Survey (SDSS). DR5 includes all survey quality data taken through June 2005 and
represents the completion of the SDSS-I project (whose successor, SDSS-II will
continue through mid-2008). It includes five-band photometric data for 217
million objects selected over 8000 square degrees, and 1,048,960 spectra of
galaxies, quasars, and stars selected from 5713 square degrees of that imaging
data. These numbers represent a roughly 20% increment over those of the Fourth
Data Release; all the data from previous data releases are included in the
present release. In addition to "standard" SDSS observations, DR5 includes
repeat scans of the southern equatorial stripe, imaging scans across M31 and
the core of the Perseus cluster of galaxies, and the first spectroscopic data
from SEGUE, a survey to explore the kinematics and chemical evolution of the
Galaxy. The catalog database incorporates several new features, including
photometric redshifts of galaxies, tables of matched objects in overlap regions
of the imaging survey, and tools that allow precise computations of survey
geometry for statistical investigations.Comment: ApJ Supp, in press, October 2007. This paper describes DR5. The SDSS
Sixth Data Release (DR6) is now public, available from http://www.sdss.or
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