1,524 research outputs found
Keck and Gemini spectral characterization of Lucy mission fly-by target (152830) Dinkinesh
Recently, the inner main belt asteroid (152830) Dinkinesh was identified as
an additional fly-by target for the Lucy mission. The heliocentric orbit and
approximate absolute magnitude of Dinkinesh are known, but little additional
information was available prior to its selection as a target. In particular,
the lack of color spectrophotometry or spectra made it impossible to assign a
spectral type to Dinkinesh from which its albedo could be estimated. We set out
to remedy this knowledge gap by obtaining visible wavelength spectra with the
Keck telescope on 2022 November 23 and with Gemini-South on 2022 December 27.
The spectra measured with the Keck I/Low Resolution Imaging Spectrometer (LRIS)
and the Gemini South/Gemini Multi-Object Spectrograph South (GMOS-S) are most
similar to the average spectrum of S- and Sq-type asteroids. The most
diagnostic feature is the 151 silicate absorption feature at
0.9-1.0~micron. Small S- and Sq-type asteroids have moderately high
albedos ranging from 0.17-0.35. Using this albedo range for Dinkinesh in
combination with measured absolute magnitude, it is possible to derive an
effective diameter and surface brightness for this body. The albedo, size and
surface brightness are important inputs required for planning a successful
encounter by the Lucy spacecraft.Comment: 7 pages, 1 figure. Under review in Icaru
Evaluation of a Simplified Measurement for Low Glomerular Filtration Rates With lndium-111 DTPA
A rapid new method for measuring glomerular filtration rates using 111In diethylenetriamine pentaacetic acid (111In- DTPA) was evaluated with 39 patients who showed marked impairment of renal function (creatinine clearance less than 20 ml/min). A simple, single compartment system was assumed. For comparison, parallel inulin and creatinine clearances were performed. High linear correlations (r = 0.96-0.97) were demonstrated when 111In- DTPA clearances were compared with the standard nonisotopic tests. Initial data indicate that reliable isotopic clearance values could be obtained for low clearances by withdrawing only two blood samples for assay at 6 and 48 hours after isotope injection (without urine assay)
Immunologic and virologic findings in a bull chronically infected with noncytopathic bovine viral diarrhea virus
In February 1985, a 2-year-old bull with inappetence and weight loss of 1-week duration was examined by the field services staff of the Iowa State University College of Veterinary Medicine. The bull had a normal rectal temperature, decreased rumen activity, and loose feces and walked with a stiff gait. The hemogram was normal for hemoglobin concentration, PCV, and total plasma protein concentration, but the bull had a leukopenia which was primarily attributable to an absolute lymphopenia. Treatment consisted of antimicrobial drugs, an antidiarrheal medication, and a nonsteroidal anti-inflammatory and analgesic drug. After 3 weeks without improvement, the bull was admitted to the Iowa State University Large Animal Hospital
The use of quantitative Real-Time PCR to estimate Salmonella shed in fecal samples from naturally infected finishing pigs
The objective of this study was to describe the shedding pattern of Salmonella in finishing pigs, as well to quantify the Salmonella load. A longitudinal study was conducted in 12 cohorts of pigs in a multi-site farrow-to-finish production system. At the beginning of each cohort, 50 pigs (10 ± 2 weeks old) were randomly selected and individually identified. Individual pig fecal samples were collected and cultured every 2 weeks for 16 weeks (8 collections)
Spin states of asteroids in the Eos collisional family
Eos family was created during a catastrophic impact about 1.3 Gyr ago.
Rotation states of individual family members contain information about the
history of the whole population. We aim to increase the number of asteroid
shape models and rotation states within the Eos collision family, as well as to
revise previously published shape models from the literature. Such results can
be used to constrain theoretical collisional and evolution models of the
family, or to estimate other physical parameters by a thermophysical modeling
of the thermal infrared data. We use all available disk-integrated optical data
(i.e., classical dense-in-time photometry obtained from public databases and
through a large collaboration network as well as sparse-in-time individual
measurements from a few sky surveys) as input for the convex inversion method,
and derive 3D shape models of asteroids together with their rotation periods
and orientations of rotation axes. We present updated shape models for 15
asteroids and new shape model determinations for 16 asteroids. Together with
the already published models from the publicly available DAMIT database, we
compiled a sample of 56 Eos family members with known shape models that we used
in our analysis of physical properties within the family. Rotation states of
asteroids smaller than ~20 km are heavily influenced by the YORP effect, whilst
the large objects more or less retained their rotation state properties since
the family creation. Moreover, we also present a shape model and bulk density
of asteroid (423) Diotima, an interloper in the Eos family, based on the
disk-resolved data obtained by the Near InfraRed Camera (Nirc2) mounted on the
W.M. Keck II telescope.Comment: Accepted for publication in ICARUS Special Issue - Asteroids: Origin,
Evolution & Characterizatio
MUSTANG 3.3 Millimeter Continuum Observations of Class 0 Protostars
We present observations of six Class 0 protostars at 3.3 mm (90 GHz) using
the 64-pixel MUSTANG bolometer camera on the 100-m Green Bank Telescope. The
3.3 mm photometry is analyzed along with shorter wavelength observations to
derive spectral indices (S_nu ~ nu^alpha) of the measured emission. We utilize
previously published dust continuum radiative transfer models to estimate the
characteristic dust temperature within the central beam of our observations. We
present constraints on the millimeter dust opacity index, beta, between 0.862
mm, 1.25 mm, and 3.3 mm. Beta_mm typically ranges from 1.0 to 2.4 for Class 0
sources. The relative contributions from disk emission and envelope emission
are estimated at 3.3 mm. L483 is found to have negligible disk emission at 3.3
mm while L1527 is dominated by disk emission within the central beam. The
beta_mm^disk <= 0.8 - 1.4 for L1527 indicates that grain growth is likely
occurring in the disk. The photometry presented in this paper may be combined
with future interferometric observations of Class 0 envelopes and disks.Comment: 19 pages, 3 figures, AJ accepted, in pres
ETL-0254, Terrain analysis procedural guide for soil, February 1981
This report is one in a series of terrain analysis procedural guides being developed in support of the Topographic Support System (TSS). It was written specifically for a U.S. Army terrain analyst and presents the step-by- step methods needed for extraction, reducing, and recording soil information on a factor overlay and supporting data table. It is a contribution to the Department of Defense terrain intelligence effort.
The report contains a detailed bibliography and a lengthy glossary
Temporal light field reconstruction for rendering distribution effects
Traditionally, effects that require evaluating multidimensional integrals for each pixel, such as motion blur, depth of field, and soft shadows, suffer from noise due to the variance of the high-dimensional integrand. In this paper, we describe a general reconstruction technique that exploits the anisotropy in the temporal light field and permits efficient reuse of samples between pixels, multiplying the effective sampling rate by a large factor. We show that our technique can be applied in situations that are challenging or impossible for previous anisotropic reconstruction methods, and that it can yield good results with very sparse inputs. We demonstrate our method for simultaneous motion blur, depth of field, and soft shadows
ETL-0254, Terrain analysis procedural guide for soil, February 1981
This report is one in a series of terrain analysis procedural guides being developed in support of the Topographic Support System (TSS). It was written specifically for a U.S. Army terrain analyst and presents the step-by- step methods needed for extraction, reducing, and recording soil information on a factor overlay and supporting data table. It is a contribution to the Department of Defense terrain intelligence effort.
The report contains a detailed bibliography and a lengthy glossary
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