1,095 research outputs found
A Simplification Heuristic For Large Flow Tables
Flow tables specifying large asynchronous sequential circuits often contain more internal states than are required to specify desired circuit behavior. Known minimization techniques appear unsuited for reduction of such large (rows X columns \u3e 250) flow tables, because of excessive computation and intermediate data requirements for problems of this size. The algorithm described here is intended to rapidly produce a simplified-but in general non-minimal-flow table. It is most economical when applied to extremely large tables and was devised primarily for automated design applications. The procedure has been programmed in PL/1 and has been incorporated into an asynchronous sequential circuit design automation system developed at the University of Missouri-Rolla. Typical flow table simplification times obtained using the program are cited. In one test re-duction of a 217 row x 8 column table to 39x8 required about 2.6 minutes (the minimum table in this case was known to be 23x8)
The Three-Dimensional Structure of Interior Ejecta in Cassiopeia A at High Spectral Resolution
We used the Spitzer Space Telescope's Infrared Spectrograph to create a high
resolution spectral map of the central region of the Cassiopeia A supernova
remnant, allowing us to make a Doppler reconstruction of its 3D structure. The
ejecta responsible for this emission have not yet encountered the remnant's
reverse shock or the circumstellar medium, making it an ideal laboratory for
exploring the dynamics of the supernova explosion itself. We observe that the
O, Si, and S ejecta can form both sheet-like structures as well as filaments.
Si and O, which come from different nucleosynthetic layers of the star, are
observed to be coincident in velocity space in some regions, and separated by
500 km/s or more in others. Ejecta traveling toward us are, on average, ~900
km/s slower than the material traveling away from us. We compare our
observations to recent supernova explosion models and find that no single model
can simultaneously reproduce all the observed features. However, models of
different supernova explosions can collectively produce the observed geometries
and structures of the interior emission. We use the results from the models to
address the conditions during the supernova explosion, concentrating on
asymmetries in the shock structure. We also predict that the back surface of
Cassiopeia A will begin brightening in ~30 years, and the front surface in ~100
years.Comment: 35 pages, 16 figures, accepted to Ap
Generation Of Design Equations In Asynchronous Sequential Circuits
One step in the synthesis procedure for realizing an asynchronous sequential switching circuit is the generation of next-state and output state equations from a simplified and coded flow table description of the circuit. The usual approach for determining these equations is to first construct a state table from the coded flow table, and then construct transition and output tables. For large flow tables this can be quite a lengthy procedure. This note describes an algorithm which simplifies the synthesis procedure for normal fundamental-mode circuits by permitting the determination of these equations without explicit construction of the state table, transition table, or output table. The algorithm has been programmed in PL/1. Copyright © 1969 by The Institute of Electrical and Electronics Engineers, Inc
The Three-Dimensional Structure of Cassiopeia A
We used the Spitzer Space Telescope's Infrared Spectrograph to map nearly the
entire extent of Cassiopeia A between 5-40 micron. Using infrared and Chandra
X-ray Doppler velocity measurements, along with the locations of optical ejecta
beyond the forward shock, we constructed a 3-D model of the remnant. The
structure of Cas A can be characterized into a spherical component, a tilted
thick disk, and multiple ejecta jets/pistons and optical fast-moving knots all
populating the thick disk plane. The Bright Ring in Cas A identifies the
intersection between the thick plane/pistons and a roughly spherical reverse
shock. The ejecta pistons indicate a radial velocity gradient in the explosion.
Some ejecta pistons are bipolar with oppositely-directed flows about the
expansion center while some ejecta pistons show no such symmetry. Some ejecta
pistons appear to maintain the integrity of the nuclear burning layers while
others appear to have punched through the outer layers. The ejecta pistons
indicate a radial velocity gradient in the explosion. In 3-D, the Fe jet in the
southeast occupies a "hole" in the Si-group emission and does not represent
"overturning", as previously thought. Although interaction with the
circumstellar medium affects the detailed appearance of the remnant and may
affect the visibility of the southeast Fe jet, the bulk of the symmetries and
asymmetries in Cas A are intrinsic to the explosion.Comment: Accepted to ApJ. 54 pages, 21 figures. For high resolution figures
and associated mpeg movie and 3D PDF files, see
http://homepages.spa.umn.edu/~tdelaney/pape
Re-imagining the data collection and analysis research process by proposing a rapid qualitative data collection and analytic roadmap applied to the dynamic context of precision medicine
Our implementation science study focuses on implementing a new way of practice and offers methodological specificity about how to rapidly investigate an individually tailored precision medicine intervention. A qualitative study advancing a new methodology for speedily identifying barriers and enablers to implementation in the context of childhood cancer. Data were collected through rapid ethnography, coded using the Consolidated Framework for Implementation Research, and analysed by Sentiment Analysis. Thirty-eight data collection events occurred during 14 multidisciplinary tumour board meetings, 14 curation meetings, and 10 informal conversations. Sentiment Analysis distilled Consolidated Framework for Implementation Research codes to reveal key barriers and enablers to implementation. A traffic light labelling system has been used to present levels of positivity and negativity (green for strong enablers and red for strong barriers), highlighting levels of concern regarding implementation. Within the intervention design characteristics, “Adaptability” was the strongest enabler and “Design quality and safety” the strongest barrier. Among the contextual factors: “Networks and communication” were the strongest enabler, and “Available resources” were the strongest barrier. Overall, there was a higher percentage of negative sentiment towards intervention design characteristics and contextual factors than positive sentiment, while more concerns were raised about intervention design factors than contextual factors. This study offers a rapid qualitative data collection and analytic methodological roadmap for establishing barriers and enablers to a paediatric precision medicine intervention
High protein diet maintains glucose production during exercise-induced energy deficit: a controlled trial
<p>Abstract</p> <p>Background</p> <p>Inadequate energy intake induces changes in endogenous glucose production (GP) to preserve muscle mass. Whether addition provision of dietary protein modulates GP response to energy deficit is unclear. The objective was to determine whether exercise-induced energy deficit effects on glucose metabolism are mitigated by increased dietary protein.</p> <p>Methods</p> <p>Nineteen men ([mean ± SD] 23 ± 2 y, VO<sub>2peak </sub>59 ± 5 ml·kg<sup>-1</sup>·min<sup>-1</sup>) were divided into three groups, two consuming moderate (MP; 0.9 g protein kg<sup>-1 </sup>d<sup>-1</sup>), and one high (HP; 1.8 g protein kg<sup>-1 </sup>d<sup>-1</sup>) protein diets (55% energy from carbohydrate) for 11 days. Following 4 days of energy balance (D1-4), energy expenditure was increased for 7 days (D5-12) in all groups. Energy intake was unchanged in two, creating a 1000 kcal d<sup>-1 </sup>deficit (DEF-MP, DEF-HP; n = 6, both groups), whereas energy balance was maintained in the third (BAL-MP, n = 7). Biochemical markers of substrate metabolism were measured during fasting rest on D4 and D12, as were GP and contribution of gluconeogenesis to endogenous glucose production (<it>f</it><sub>gng</sub>) using 4-h primed, continuous infusions of [6,6-<sup>2</sup>H<sub>2</sub>]glucose (dilution-method) and [2-<sup>13</sup>C]glycerol (MIDA technique). Glycogen breakdown (GB) was derived from GP and <it>f</it><sub>gng</sub>.</p> <p>Results</p> <p>Plasma β-hydroxybutyrate levels increased, and plasma glucose and insulin declined from D4 to D12, regardless of group. DEF-MP experienced decreased plasma GP from D4 to D12 ([mean change ± SD] 0.24 ± 0.24 mg·kg<sup>-1</sup>·min<sup>-1</sup>), due to reduced GB from D4 (1.40 ± 0.28 mg·kg<sup>-1</sup>·min<sup>-1</sup>) to D12 (1.16 ± 0.17 mg·kg<sup>-1</sup>·min<sup>-1</sup>), P < 0.05. Conversely, BAL-MP and DEF-HP sustained GP from D4 to D12 ([mean change ± SD] 0.1 ± 0.5 and 0.0 ± 0.2 mg·kg<sup>-1</sup>·min<sup>-1</sup>, respectively) by maintaining GB.</p> <p>Conclusion</p> <p>Exercise-induced energy deficit decreased GP and additional dietary protein mitigated that effect.</p
Aerobic fitness does not modulate protein metabolism in response to increased exercise: a controlled trial
© 2009 Smith et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
Using Rasch analysis to form plausible health states amenable to valuation: the development of CORE-6D from CORE-OM in order to elicit preferences for common mental health problems
Purpose: To describe a new approach for deriving a preference-based index from a condition specific measure that uses Rasch analysis to develop health states.
Methods: CORE-OM is a 34-item instrument monitoring clinical outcomes of people with common mental health problems. CORE-OM is characterised by high correlation across its domains. Rasch analysis was used to reduce the number of items and response levels in order to produce a set of unidimensionally-behaving items, and to generate a credible set of health states corresponding to different levels of symptom severity using the Rasch item threshold map.
Results: The proposed methodology resulted in the development of CORE-6D, a 2-dimensional health state description system consisting of a unidimensionally-behaving 5-item emotional component and a physical symptom item. Inspection of the Rasch item threshold map of the emotional component helped identify a set of 11 plausible health states, which, combined with the physical symptom item levels, will be used for the valuation of the instrument, resulting in the development of a preference-based index.
Conclusions: This is a useful new approach to develop preference-based measures where the domains of a measure are characterised by high correlation. The CORE-6D preference-based index will enable calculation of Quality Adjusted Life Years in people with common mental health problems
Far-field Unlabelled Super-Resolution Imaging with Superoscillatory Illumination
Unlabelled super-resolution is the next grand challenge in imaging. Stimulated emission depletion and single-molecule microscopies have revolutionised the life sciences but are still limited by the need for reporters (labels) embedded within the sample. While the Veselago-Pendry “super-lens” using a negative-index metamaterial is a promising idea for imaging beyond the diffraction limit, there are substantial technological challenges to its realisation. Another route to far-field subwavelength focusing is using optical superoscillations: engineered interference of multiple coherent waves creating an, in principle, arbitrarily small hotspot. Here we demonstrate microscopy with superoscillatory illumination of the object and describe its underlying principles. We show that far-field images taken with superoscillatory
illumination are themselves superoscillatory and hence can reveal fine structural details of the object that are lost in conventional far-field imaging. We show that the resolution of a superoscillatory microscope is determined by the size of the hotspot, rather than the bandwidth of the optical instrument. We demonstrate high-frame-rate polarisation-contrast imaging of unmodified living cells with resolution significantly exceeding that achievable with conventional instruments. This non-algorithmic, low-phototoxicity imaging technology is a powerful tool both for biological research and for super-resolution imaging of samples that do not allow labelling, such as the interior of silicon chips
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