2,172 research outputs found
A new method for imaging nuclear threats using cosmic ray muons
Muon tomography is a technique that uses cosmic ray muons to generate three
dimensional images of volumes using information contained in the Coulomb
scattering of the muons. Advantages of this technique are the ability of cosmic
rays to penetrate significant overburden and the absence of any additional dose
delivered to subjects under study above the natural cosmic ray flux.
Disadvantages include the relatively long exposure times and poor position
resolution and complex algorithms needed for reconstruction. Here we
demonstrate a new method for obtaining improved position resolution and
statistical precision for objects with spherical symmetry
High-Resolution Image Reconstruction from a Sequence of Rotated and Translated Frames and its Application to an Infrared Imaging System
Some imaging systems employ detector arrays that are not sufficiently dense to meet the Nyquist criterion during image acquisition. This is particularly true for many staring infrared imagers. Thus, the full resolution afforded by the optics is not being realized in such a system. This paper presents a technique for estimating a high-resolution image, with reduced aliasing, from a sequence of undersampled rotated and translationally shifted frames. Such an image sequence can be obtained if an imager is mounted on a moving platform, such as an aircraft. Several approaches to this type of problem have been proposed in the literature. Here we extend some of this previous work. In particular, we define an observation model that incorporates knowledge of the optical system and detector array. The high-resolution image estimate is formed by minimizing a regularized cost function based on the observation model. We show that with the proper choice of a tuning parameter, our algorithm exhibits robustness in the presence of noise. We consider both gradient descent and conjugate-gradient optimization procedures to minimize the cost function. Detailed experimental results are provided to illustrate the performance of the proposed algorithm using digital video from an infrared imager
Elementary Psychology (University of Georgia)
This Grants Collection for Elementary Psychology was created under a Round Two ALG Textbook Transformation Grant.
Affordable Learning Georgia Grants Collections are intended to provide faculty with the frameworks to quickly implement or revise the same materials as a Textbook Transformation Grants team, along with the aims and lessons learned from project teams during the implementation process.
Documents are in .pdf format, with a separate .docx (Word) version available for download. Each collection contains the following materials: Linked Syllabus Initial Proposal Final Reporthttps://oer.galileo.usg.edu/psychology-collections/1003/thumbnail.jp
Comparison of quantum mechanical and classical trajectory calculations of cross sections for ion-atom impact ionization of negative - and positive -ions for heavy ion fusion applications
Stripping cross sections in nitrogen have been calculated using the classical
trajectory approximation and the Born approximation of quantum mechanics for
the outer shell electrons of 3.2GeV I and Cs ions. A large
difference in cross section, up to a factor of six, calculated in quantum
mechanics and classical mechanics, has been obtained. Because at such high
velocities the Born approximation is well validated, the classical trajectory
approach fails to correctly predict the stripping cross sections at high
energies for electron orbitals with low ionization potential.Comment: submitted to Phys. Rev.
Behavioral/Systems/Cognitive A Role for Perirhinal Cortex in Memory for Novel Object-Context Associations
It is debated whether functional divisions between structures in the medial temporal lobe (MTL) , ). In the latter theory, complex object representations in PrC are capable of supporting memory for objects as well as for object-context associations, particularly when there is a demand to discriminate between highly visually similar objects (Cowell et al., 2010). To adjudicate between these accounts, human participants were scanned while making two different judgments about visually presented objects (is the object common or uncommon, or does the object have more edges or curves). In a subsequent, unscanned, retrieval phase, participants made item (old/new) followed by context (encoding task) judgments about previously seen and novel objects. Neural activity at encoding was separated according to the accuracy of the retrieval judgments. PrC activity predicted successful item-context judgments, a result that remained when itemmemory strength was equated across objects for which the context was remembered or forgotten. These data imply that the function of PrC goes beyond processing item-based memory information, contributing additionally to memory for item-context associations when the stimuli are object
Spitzer IRAC observations of newly-discovered planetary nebulae from the Macquarie-AAO-Strasbourg H-alpha Planetary Nebula Project
We compare H-alpha, radio continuum, and Spitzer Space Telescope (SST) images
of 58 planetary nebulae (PNe) recently discovered by the Macquarie-AAO-Strasbo-
urg H-alpha PN Project (MASH) of the SuperCOSMOS H-alpha Survey. Using InfraRed
Array Camera (IRAC) data we define the IR colors of PNe and demonstrate good
isolation between these colors and those of many other types of astronomical
object. The only substantive contamination of PNe in the color-color plane we
illustrate is due to YSOs. However, this ambiguity is readily resolved by the
unique optical characteristics of PNe and their environs. We also examine the
relationships between optical and MIR morphologies from 3.6 to 8.0um and
explore the ratio of mid-infrared (MIR) to radio nebular fluxes, which is a
valuable discriminant between thermal and nonthermal emission. MASH emphasizes
late evolutionary stages of PNe compared with previous catalogs, enabling study
of the changes in MIR and radio flux that attend the aging process. Spatially
integrated MIR energy distributions were constructed for all MASH PNe observed
by the GLIMPSE Legacy Project, using the H-alpha morphologies to establish the
dimensions for the calculations of the Midcourse Space Experiment (MSX), IRAC,
and radio continuum (from the Molonglo Observatory Synthesis Telescope and the
Very Large Array) flux densities. The ratio of IRAC 8.0-um to MSX 8.3-um flux
densities provides a measure of the absolute diffuse calibration of IRAC at 8.0
um. We independently confirm the aperture correction factor to be applied to
IRAC at 8.0um to align it with the diffuse calibration of MSX. The result
agrees with the recommendations of the Spitzer Science Center and with results
from a parallel study of HII regions. These PNe probe the diffuse calibration
of IRAC on a spatial scale of 9-77 arcsec.Comment: 48 pages, LaTeX (aastex), incl. 18 PostScript (eps) figures and 3
tables. Accepted by Astrophysical Journa
Synthesis and NMR Characterization of a New Series of Thiazole-2-Carboxaldehyde Thiosemicarbozone Compounds
This work will be the synthesis of a series of thiazole-carboxaldehyde-thiosemicarbazone ligands. After the synthesis and purification of these ligands, the new compounds went through analysis using the NMR spectrometer and obtaining data on +H NMR, 13C NMR, HSQC (heteronuclear single quantum coherence) 1H-13C NMR and HSQC 1H-15N NMR, to obtain evidence for our predicted structures. After the analysis was complete, we reacted the new ligands with palladium to form their metal complexes
HOPS 361-C's Jet Decelerating and Precessing Through NGC 2071 IR
We present a two-epoch Hubble Space Telescope (HST) near-infrared (NIR) study
of NGC 2071 IR highlighting HOPS 361-C, a protostar producing an arced 0.2
parsec-scale jet. Proper motions for the brightest knots decrease from 350 to
100 km/s with increasing distance from the source. The [Fe II] and Pa
emission line intensity ratio gives a velocity jump through each knot of 40-50
km/s. We show a new [O I] 63 m spectrum taken with the German REciever
for Astronomy at Terahertz frequencies (GREAT) instrument aboard Stratospheric
Observatory for Infrared Astronomy (SOFIA), which give a low jet inclination.
Proper motions and jump velocities then estimate total flow speed throughout
the jet.
We model knot positions and speeds with a precessing jet that decelerates
within the host molecular cloud. The measurements are matched with a precession
period of a few thousand years and half opening angle of 15. The [Fe
II] 1.26 m to 1.64 m line intensity ratio gives the
extinction to each knot ranging from 5-30 mag. Relative to 14 mag of
extinction through the cloud from CO emission maps, the jet is well
embedded at a fractional depth from 1/5 to 4/5, and can interact with the
cloud. Our model suggests the jet is locally dissipated over 0.2 pc. This may
be because knots sweep through a wide angle, giving the cloud time to fill in
cavities opened by the jet. This contrasts with nearly unidirectional
protostellar jets that puncture host clouds and can propagate significantly
further than a quarter pc.Comment: 24 pages, 9 figures, submitted to Ap
Comprehensive Analysis of Established Dyslipidemia-Associated Loci in the Diabetes Prevention Program
Background-We assessed whether 234 established dyslipidemia-associated loci modify the effects of metformin treatment and lifestyle intervention (versus placebo control) on lipid and lipid subfraction levels in the Diabetes Prevention Program randomized controlled trial. Methods and Results-We tested gene treatment interactions in relation to baseline-adjusted follow-up blood lipid concentrations (high-density lipoprotein [HDL] and low-density lipoprotein-cholesterol, total cholesterol, and triglycerides) and lipoprotein subfraction particle concentrations and size in 2993 participants with pre-diabetes. Of the previously reported single-nucleotide polymorphism associations, 32.5% replicated at PP>1.1×10-16) with their respective baseline traits for all but 2 traits. Lifestyle modified the effect of the genetic risk score for large HDL particle numbers, such that each risk allele of the genetic risk scores was associated with lower concentrations of large HDL particles at follow-up in the lifestyle arm (β=-0.11 μmol/L per genetic risk scores risk allele; 95% confidence interval,-0.188 to-0.033; P=5×10-3; Pinteraction=1×10-3 for lifestyle versus placebo), but not in the metformin or placebo arms (P>0.05). In the lifestyle arm, participants with high genetic risk had more favorable or similar trait levels at 1-year compared with participants at lower genetic risk at baseline for 17 of the 20 traits. Conclusions-Improvements in large HDL particle concentrations conferred by lifestyle may be diminished by genetic factors. Lifestyle intervention, however, was successful in offsetting unfavorable genetic loading for most lipid traits. Clinical Trial Registration-URL: https://www.clinicaltrials.gov. Unique Identifier: NCT00004992
Toward improving practices for submission of diagnostic tissue blocks for National Cancer Institute clinical trials
OBJECTIVES: The National Cancer Institute (NCI) National Clinical Trials Network performs phase II and III clinical trials, which increasingly rely on the submission of diagnostic formalin-fixed, paraffin-embedded tissue blocks for biomarker assessment. Simultaneously, advances in precision oncology require that clinical centers maintain diagnostic specimens for ancillary, standard-of-care diagnostics. This has caused tissue blocks to become a limited resource for advancing the NCI clinical trial enterprise and the practice of modern molecular pathology.
METHODS: The NCI convened a 1-day workshop of multidisciplined experts to discuss barriers and strategic solutions to facilitate diagnostic block submission for clinical trial science, from the perspective of patient advocates, legal experts, pathologists, and clinical oncologists.
RESULTS: The expert views and opinions were carefully noted and reported.
CONCLUSIONS: Recommendations were proposed to reduce institutional barriers and to assist organizations in developing clear policies regarding diagnostic block submission for clinical trials
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