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Ionising radiation exposure from medical imaging – A review of Patient's (un) awareness
Introduction: Medical imaging is the main source of artificial radiation exposure. Evidence, however, suggests that patients are poorly informed about radiation exposure when attending diagnostic scans. This review provides an overview of published literature with a focus on nuclear medicine patients on the level of awareness of radiation exposure from diagnostic imaging. Methods: A review of available literature on awareness, knowledge and perception of ionising radiation in medical imaging was conducted. Articles that met the inclusion criteria were subjected to critical appraisal using the Mixed Methods Appraisal Tool. Results: 140 articles identified and screened for eligibility, 24 critically assessed and 4 studies included in synthesis. All studies demonstrated that patients were generally lacking awareness about radiation exposure and highlighted a lack of communication between healthcare professionals and patients with respect to radiation exposure. Conclusion: Studies demonstrate a need to better inform patients about their radiation exposure, and further studies focusing on nuclear medicine patients are particularly warranted. Implications for practice: Adequate and accurate information is crucial to ensure the principle of informed consent is present
Epidemic threshold in structured scale-free networks
We analyze the spreading of viruses in scale-free networks with high
clustering and degree correlations, as found in the Internet graph. For the
Suscetible-Infected-Susceptible model of epidemics the prevalence undergoes a
phase transition at a finite threshold of the transmission probability.
Comparing with the absence of a finite threshold in networks with purely random
wiring, our result suggests that high clustering and degree correlations
protect scale-free networks against the spreading of viruses. We introduce and
verify a quantitative description of the epidemic threshold based on the
connectivity of the neighborhoods of the hubs.Comment: 4 pages, 4 figure
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Radiation exposure awareness from patients undergoing nuclear medicine diagnostic 99mTc-MDP bone scans and 2-deoxy-2-(18F) fluoro-D-glucose PET/computed tomography scans
INTRODUCTION: Medical imaging is on average the largest source of artificial radiation exposure worldwide. This study seeks to understand patient's awareness of radiation exposure derived from nuclear medicine diagnostic scans and assess if current information provided by leaflets is adequate.
METHODS: Single-centre cross-sectional questionnaire study applied to bone scan and FDG PET/computed tomography patients, at a nuclear medicine and PET/computed tomography department over a 15-week period in 2018. Questionnaires on dose comparators were designed in collaboration with patients, public, and experts in radiation exposure. Qualitative data were analysed using thematic analysis and quantitative data using SPSS (V. 24).
RESULTS: A total of 102 questionnaires were completed (bone scan = 50; FDG PET/computed tomography = 52). Across both groups, 33/102 (32.4%) patients reported having a reasonable understanding of nuclear medicine and 21/102 (20.6%) reported a reasonable knowledge of ionising radiations. When asked to compare the exposure dose of respective scans with common comparators 8/50 (16%) of bone scan patients and 11/52 (21.2%) FDG PET/computed tomography answered correctly. On leaflet information, 15/85 (17.6%) patients reported the leaflets do not provide enough information on radiation exposure and of these 10/15 (66.7%) commented the leaflets should incorporate more information on radiation exposure dose.
CONCLUSION: More observational and qualitative studies in collaboration with patients are warranted to evaluate patients' understanding and preferences in communication of radiation exposure from nuclear medicine imaging. This will ensure communication tools and guidelines developed to comply with ionising radiation (medical exposure) regulation 2017 are according to patients needs and preferences
Measurement of transparency ratios for protons from short-range correlated pairs
Nuclear transparency, Tp(A), is a measure of the average probability for a
struck proton to escape the nucleus without significant re-interaction.
Previously, nuclear transparencies were extructed for quasi-elastic A(e,e'p)
knockout of protons with momentum below the Fermi momentum, where the spectral
functions are well known. In this paper we extract a novel observable, the
transparency ratio, Tp(A)/T_p(12C), for knockout of high-missing-momentum
protons from the breakup of short range correlated pairs (2N-SRC) in Al, Fe and
Pb nuclei relative to C. The ratios were measured at momentum transfer Q^2 >
1.5 (GeV/c)^2 and x_B > 1.2 where the reaction is expected to be dominated by
electron scattering from 2N-SRC. The transparency ratios of the knocked-out
protons coming from 2N-SRC breakup are 20 - 30% lower than those of previous
results for low missing momentum. They agree with Glauber calculations and
agree with renormalization of the previously published transparencies as
proposed by recent theoretical investigations. The new transparencies scale as
A^-1/3, which is consistent with dominance of scattering from nucleons at the
nuclear surface.Comment: 6 pages, 4 figure
Current-induced non-adiabatic spin torques and domain wall motion with spin relaxation in a ferromagnetic metallic wire
Within the s-d model description, we derive the current-driven spin torque in
a ferromagnet, taking explicitly into account a spin-relaxing Caldeira-Leggett
bath coupling to the s-electrons. We derive Bloch-Redfield equations of motion
for the s-electron spin dynamics, and formulate a systematic gradient expansion
to obtain non-adiabatic (higher-order) corrections to the well-known adiabatic
(first-order) spin torque. We provide simple analytical expressions for the
second-order spin torque. The theory is applied to current-driven domain wall
motion. Second-order contributions imply a deformation of a transverse
tail-to-tail domain wall. The wall center still moves with a constant velocity
that now depends on the spin-polarized current in a non-trivial manner.Comment: Phys. Rev. B, in press, replaced with published versio
Regulation of Marginal Zone B-Cell Differentiation by MicroRNA-146a.
B-cell development in the bone marrow is followed by specification into functional subsets in the spleen, including marginal zone (MZ) B-cells. MZ B-cells are classically characterized by T-independent antigenic responses and require the elaboration of distinct gene expression programs for development. Given their role in gene regulation, it is not surprising that microRNAs are important factors in B-cell development. Recent work demonstrated that deficiency of the NFÎşB feedback regulator, miR-146a, led to a range of hematopoietic phenotypes, but B-cell phenotypes have not been extensively characterized. Here, we found that miR-146a-deficient mice demonstrate a reduction in MZ B-cells, likely from a developmental block. Utilizing high-throughput sequencing and comparative analysis of developmental stage-specific transcriptomes, we determined that MZ cell differentiation was impaired due to decreases in Notch2 signaling. Our studies reveal miR-146a-dependent B-cell phenotypes and highlight the complex role of miR-146a in the hematopoietic system
Utilitarian Collective Choice and Voting
In his seminal Social Choice and Individual Values, Kenneth Arrow stated that his theory applies to voting. Many voting theorists have been convinced that, on account of Arrow’s theorem, all voting methods must be seriously flawed. Arrow’s theory is strictly ordinal, the cardinal aggregation of preferences being explicitly rejected. In this paper I point out that all voting methods are cardinal and therefore outside the reach of Arrow’s result.
Parallel to Arrow’s ordinal approach, there evolved a consistent cardinal theory of collective choice. This theory, most prominently associated with the work of Harsanyi, continued the older utilitarian tradition in a more formal style. The purpose of this paper is to show that various derivations of utilitarian SWFs can also be used to derive utilitarian voting (UV). By this I mean a voting rule that allows the voter to score each alternative in accordance with a given scale. UV-k indicates a scale with k distinct values. The general theory leaves k to be determined on pragmatic grounds. A (1,0) scale gives approval voting. I prefer the scale (1,0,-1) and refer to the resulting voting rule as evaluative voting.
A conclusion of the paper is that the defects of conventional voting methods result not from Arrow’s theorem, but rather from restrictions imposed on voters’ expression of their preferences.
The analysis is extended to strategic voting, utilizing a novel set of assumptions regarding voter behavior
Systems, interactions and macrotheory
A significant proportion of early HCI research was guided by one very clear vision: that the existing theory base in psychology and cognitive science could be developed to yield engineering tools for use in the interdisciplinary context of HCI design. While interface technologies and heuristic methods for behavioral evaluation have rapidly advanced in both capability and breadth of application, progress toward deeper theory has been modest, and some now believe it to be unnecessary. A case is presented for developing new forms of theory, based around generic “systems of interactors.” An overlapping, layered structure of macro- and microtheories could then serve an explanatory role, and could also bind together contributions from the different disciplines. Novel routes to formalizing and applying such theories provide a host of interesting and tractable problems for future basic research in HCI
An Atlas of Warm AGN and Starbursts from the IRAS Deep Fields
We present 180 AGN candidates based on color selection from the IRAS
slow-scan deep observations, with color criteria broadened from the initial
Point-Source Catalog samples to include similar objects with redshifts up to
z=1 and allowing for two-band detections. Spectroscopic identifications have
been obtained for 80 (44%); some additional ones are secure based on radio
detections or optical morphology, although yet unobserved spectroscopically.
These spectroscopic identifications include 13 Sy 1 galaxies, 17 Sy 2 Seyferts,
29 starbursts, 7 LINER systems, and 13 emission-line galaxies so heavily
reddened as to remain of ambiguous classification. The optical magnitudes range
from R=12.0-20.5; counts suggest that incompleteness is important fainter than
R=15.5. Redshifts extend to z=0.51, with a significant part of the sample at
z>0.2. The sample includes slightly more AGN than star-forming systems among
those where the spectra contain enough diagnostic feature to make the
distinction. The active nuclei include several broad-line objects with strong
Fe II emission, and composite objects with the absorption-line signatures of
fading starbursts. These AGN with warm far-IR colors have little overlap with
the "red AGN" identified with 2MASS; only a single Sy 1 was detected by 2MASS
with J-K > 2. Some reliable IRAS detections have either very faint optical
counterparts or only absorption-line galaxies, potentially being deeply
obscured AGN. The IRAS detections include a newly identified symbiotic star,
and several possible examples of the "Vega phenomenon", including dwarfs as
cool as type K. Appendices detail these candidate stars, and the
optical-identification content of a particularly deep set of high-latitude IRAS
scans (probing the limits of optical identification from IRAS data alone).Comment: ApJ Suppl, in press. Figures converted to JPEG/GIF for better
compression; PDF with full-resolution figures available before publication at
http://www.astr.ua.edu/keel/aoagn.pd
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