1,527 research outputs found
Scientific Visualization Using the Flow Analysis Software Toolkit (FAST)
Over the past few years the Flow Analysis Software Toolkit (FAST) has matured into a useful tool for visualizing and analyzing scientific data on high-performance graphics workstations. Originally designed for visualizing the results of fluid dynamics research, FAST has demonstrated its flexibility by being used in several other areas of scientific research. These research areas include earth and space sciences, acid rain and ozone modelling, and automotive design, just to name a few. This paper describes the current status of FAST, including the basic concepts, architecture, existing functionality and features, and some of the known applications for which FAST is being used. A few of the applications, by both NASA and non-NASA agencies, are outlined in more detail. Described in the Outlines are the goals of each visualization project, the techniques or 'tricks' used lo produce the desired results, and custom modifications to FAST, if any, done to further enhance the analysis. Some of the future directions for FAST are also described
https://doi.org/10.3389/fnins.2017.00219 Decreasing Sedentary Behavior: Effects on Academic Performance, Meta-Cognition, and Sleep
There is growing interest in using activity workstations as a method of increasing light physical activity in normally sedentary environments. The current study (N = 117) compared the effects of studying in college students while slowly pedaling a stationary bike with a desktop with studying at traditional desks across 10 weeks in an academic semester. The students were assigned to study either on the stationary bike or at a traditional desk located in the campus library for a minimum of 2 h a week. During the 10 weeks, the students studied for tests or worked on other required academic activities while working at their assigned desk. In addition, the participants completed a pre survey, weekly surveys, and a post survey. We found that although students studying at the traditional desks reported more ease of studying and more effective studying than those using the stationary bikes, the two groups performed equally well on tests in an introductory psychology course. Moreover, the students using the traditional desks reported a decrease in sleep quality later in the semester while those using the activity workstation reported stable levels of sleep quality. The current results indicate that activity workstations could be implemented in university settings to encourage light physical activity without negatively affecting academic performance while providing possible long-term health and well-being benefits. Furthermore, the results suggests that activity workstations could be a means of combating sedentary behavior in environments where individuals are expected to sit either while waiting (e.g., doctor\u27s waiting rooms, airports) or when completing a necessary task (e.g., the workplace, educational settings)
The Radial Orbit Instability in Collisionless N-Body Simulations
Using a suite of self-gravitating, collisionless N-body models, we
systematically explore a parameter space relevant to the onset and behavior of
the radial orbit instability (ROI), whose strength is measured by the systemic
axis ratios of the models. We show that a combination of two initial
conditions, namely the velocity anisotropy and the virial ratio, determines
whether a system will undergo ROI and exactly how triaxial the system will
become. A third initial condition, the radial shape of the density profile,
plays a smaller, but noticeable role. Regarding the dynamical development of
the ROI, the instability a) begins after systems collapse to their most compact
configuration and b) evolves fastest when a majority of the particles have
radially anisotropic orbits while there is a lack of centrally-concentrated
isotropic orbits. We argue that this is further evidence that self-reinforcing
torques are the key to the onset of the ROI. Our findings support the idea that
a separate orbit instability plays a role in halting the ROI.Comment: accepted for publication in ApJ. 9 figures in emulateapj styl
Interpolation of landslide movements to improve the accuracy of 4D geoelectrical monitoring
Measurement sensors permanently installed on landslides will inevitably change their position over time due to mass movements. To interpret and correct the recorded data, these movements have to be determined. This is especially important in the case of geoelectrical monitoring, where incorrect sensor positions produce strong artefacts in the resulting resistivity models. They may obscure real changes, which could indicate triggering mechanisms for landslide failure or reactivation. In this paper we introduce a methodology to interpolate movements from a small set of sparsely distributed reference points to a larger set of electrode locations. Within this methodology we compare three interpolation techniques, i.e., a piecewise planar, bi-linear spline, and a kriging based interpolation scheme. The performance of these techniques is tested on a synthetic and a real-data example, showing a recovery rate of true movements to about 1% and 10% of the electrode spacing, respectively. The significance for applying the proposed methodology is demonstrated by inverse modelling of 4D electrical resistivity tomography data, where it is shown that by correcting for sensor movements corresponding artefacts can virtually be removed and true resistivity changes be imaged
Combined population genomic screening for three high-risk conditions in Australia: a modelling study
BACKGROUND:
No previous health-economic evaluation has assessed the impact and cost-effectiveness of offering combined adult population genomic screening for mutliple high-risk conditions in a national public healthcare system.
METHODS:
This modeling study assessed the impact of offering combined genomic screening for hereditary breast and ovarian cancer, Lynch syndrome and familial hypercholesterolaemia to all young adults in Australia, compared with the current practice of clinical criteria-based testing for each condition separately. The intervention of genomic screening, assumed as an up-front single cost in the first annual model cycle, would detect pathogenic variants in seven high-risk genes. The simulated population was 18–40 year-olds (8,324,242 individuals), modelling per-sample test costs ranging AU1200 (base-case AU200 per-test, genomic screening would require an investment of AU23,926 (∼£12,050/€14,110/US4758/QALY was obtained. Sensitivity analysis for the base case indicated that combined genomic screening would be cost-effective under 70% of simulations, cost-saving under 25% and not cost-effective under 5%. Threshold analysis showed that genomic screening would be cost-effective under the AU325 (∼£164/€192/US$208).
INTERPRETATION:
Our findings suggest that offering combined genomic screening for high-risk conditions to young adults would be cost-effective in the Australian public healthcare system, at currently realistic testing costs. Other matters, including psychosocial impacts, ethical and societal issues, and implementation challenges, also need consideration.
FUNDING:
Australian Government, Department of Health, Medical Research Future Fund, Genomics Health Futures Mission (APP2009024). National Heart Foundation Future Leader Fellowship (102604)
Four-dimensional imaging of moisture dynamics during landslide reactivation
Landslides pose significant risks to communities and infrastructure, and mitigating these risks relies on understanding landslide causes and triggering processes. It has been shown that geophysical surveys can significantly contribute to the characterization of unstable slopes. However, hydrological processes can be temporally and spatially heterogeneous, requiring their related properties to be monitored over time. Geoelectrical monitoring can provide temporal and volumetric distributions of electrical resistivity, which are directly related to moisture content. To date, studies demonstrating this capability have been restricted to 2-D sections, which are insufficient to capture the full degree of spatial heterogeneity. This study is the first to employ 4-D (i.e., 3-D time lapse) resistivity imaging on an active landslide, providing long-term data (3 years) highlighting the evolution of moisture content prior to landslide reactivation and showing its decline post reactivation. Crucially, the time-lapse inversion methodology employed here incorporates movements of the electrodes on the unstable surface. Although seasonal characteristics dominate the shallow moisture dynamics during the first 2 years with surficial drying in summer and wetting in winter, in the months preceding reactivation, moisture content increased by more than 45% throughout the slope. This is in agreement with independent data showing a significant rise in piezometric heads and shallow soil moisture contents as a result of prolonged and intense rainfall. Based on these results, remediation measures could be designed and early-warning systems implemented. Thus, resistivity monitoring that can allow for moving electrodes provides a new means for the effective mitigation of landslide risk
Safety and Efficacy of Teduglutide in Pediatric Patients With Intestinal Failure due to Short Bowel Syndrome : A 24-Week, Phase III Study
Background This study evaluated the safety and efficacy of teduglutide in pediatric patients with short bowel syndrome-associated intestinal failure (SBS-IF). Methods A 24-week, phase III trial with 2 randomized, double-blind teduglutide dose groups and a nonblinded standard of care (SOC) arm was used; patients received 0.025 mg/kg or 0.05 mg/kg teduglutide once daily. Safety end points included treatment-emergent adverse events (TEAEs) and growth parameters. The primary efficacy/pharmacodynamic end point was the number of patients who achieved a >= 20% reduction in parenteral support (PS) from baseline at week 24. Results All 59 enrolled patients completed the study (0.025 mg/kg, n = 24; 0.05 mg/kg, n = 26; SOC, n = 9). Baseline demographics and disease characteristics were comparable among groups. TEAEs were reported by 98% and 100% of patients in the teduglutide and SOC groups, respectively. The most common TEAEs in the teduglutide-treated groups were pyrexia and vomiting. The primary end point was achieved by 13 (54.2%), 18 (69.2%), and 1 (11.1%) patients who received 0.025 mg/kg teduglutide, 0.05 mg/kg teduglutide, and SOC, respectively (P <0.05 vs SOC). Both 0.025-mg/kg and 0.05-mg/kg teduglutide groups showed clinically significant reductions in PS volume (P <0.05 vs SOC), PS calories, days per week and hours per day of PS infusions, and increases in enteral nutrition and plasma citrulline at week 24 compared with baseline. Two (8.3%, 0.025 mg/kg teduglutide) and 3 patients (11.5%, 0.05 mg/kg teduglutide) achieved enteral autonomy. Conclusion The safety profile of teduglutide was similar to that reported previously in children and adults. Treatment with teduglutide was associated with significant reductions in PS for pediatric patients with SBS-IF over 24 weeks.Peer reviewe
WFPC2 Observations of Compact Star Cluster Nuclei in Low Luminosity Spiral Galaxies
We have used the Wide Field Planetary Camera 2 aboard the Hubble Space
Telescope to image the compact star cluster nuclei of the nearby, late-type,
low-luminosity spiral galaxies NGC 4395, NGC 4242, and ESO 359-029. We also
analyze archival WFPC2 observations of the compact star cluster nucleus of M33.
A comparative analysis of the structural and photometric properties of these
four nuclei is presented. All of the nuclei are very compact, with luminosity
densities increasing at small radii to the resolution limit of our data. NGC
4395 contains a Seyfert 1 nucleus with a distinct bipolar structure and bright
associated filaments which are likely due to [OIII] emission. The M33 nucleus
has a complex structure, with elongated isophotes and possible signatures of
weak activity, including a jet-like component. The other two nuclei are not
known to be active, but share similar physical size scales and luminosities to
the M33 and NGC 4395 nuclei. The circumnuclear environments of all four of our
program galaxies are extremely diffuse, have only low-to-moderate star
formation, and appear to be devoid of large quantities of dust. The central
gravitational potentials of the galaxies are also quite shallow, making the
origin of these types of `naked' nuclei problematic.Comment: to appear in the July 1999 Astronomical Journal; 38 pages (Latex), 5
tables (postscript), 21 figures (gif); postscript versions of the figures may
be obtained via anonymous ftp at
ftp://ftp.cv.nrao.edu/NRAO-staff/lmatthew/lanl-nucle
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