5,553 research outputs found
Photosensitive filler minimizes internal stresses in epoxy resins
Photosensitive filler is added to curable epoxy resins to minimize stress from internal shrinkage during curing or polymerization. Cinnamic acid resins and cinnamal ketones may be added in the amount of 1 to 3 percent by weight of the resin mixture
Exploring Fog of War Concepts in Wargame Scenarios
This thesis explores fog of war concepts through three submitted journal articles. The Department of Defense and U.S. Air Force are attempting to analyze war scenarios to aid the decision-making process; fog modeling improves realism in these wargame scenarios. The first article Navigating an Enemy Contested Area with a Parallel Search Algorithm [1] investigates a parallel algorithm\u27s speedup, compared to the sequential implementation, with varying map configurations in a tile-based wargame. The parallel speedup tends to exceed 50 but in certain situations. The sequential algorithm outperforms it depending on the configuration of enemy location and amount on the map. The second article Modeling Fog of War Effects in AFSIM [2] introduces the FAT for the AFSIM to introduce and manipulate fog in wargame scenarios. FAT integrates into AFSIM version 2.7.0 and scenario results verify the tool\u27s fog effects for positioning error, hits, and probability affect the success rate. The third article Applying Fog Analysis Tool to AFSIM Multi-Domain CLASS scenarios [3] furthers the verification of FAT to introduce fog across all war fighting domains using a set of CLASS scenarios. The success rate trends with fog impact for each domain scenario support FAT\u27s effectiveness in disrupting the decision-making process for multi-domain operations. The three articles demonstrate fog can affect search, tasking, and decision-making processes for various types of wargame scenarios. The capabilities introduced in this thesis support wargame analysts to improve decision-making in AFSIM military scenarios
Shape-dependent Depinning of a Domain Wall by a Magnetic Field and a Spin-Polarized Current
The effect of sample shape on the depinning of the domain wall (DW) driven by
an applied magnetic field or a spin-polarized current is studied theoretically.
The shape effect resulting from the modulation of the sample width (geometric
pinning) can essentially affect the DW depinning. We found a good agreement
between the ratios of the critical values of the magnetic field and the
spin-polarized current predicted by the theory and measured in the experiment.Comment: 9 pages, 5 figure
Pace and variability in the badminton jump smash and the tennis serve
Full-body three-dimensional kinematic characteristics were determined for the badminton jump smash and the tennis serve in order to investigate contributions to pace and variability.
Kinematic (400 Hz) data were collected for a group of badminton and tennis players, using an 18 camera Vicon Motion Analysis System. Each participant performed 24 jump smashes
or tennis serves. The best trials - maximal velocity with minimal marker loss - were analysed for each participant using a 18 segment rigid body model customised for each
participant using subject-specific segmental properties. Parameters were calculated describing elements of the badminton jump smash and tennis serve technique as well as variability. The effect of these technique parameters on: speed were addressed using
stepwise linear regression and on variability using one-way ANOVA. The results suggest that the fastest badminton players had a smaller elbow extension angle at the end of
retraction, a larger wrist extension angle at shuttle contact, and a larger time between preparation and shuttle contact; that accounted for 84% of variation in shuttle speed. The
results also showed that variability in the badminton smash was caused by differences in body placement, shuttle location on the racket at impact and movement timings. In the tennis serve, linear regressions showed that there were no variables significant to speed
when players hit to the right and left centre court lines. When players hit in the advantage court trunk rotation at the racket lowest point key instant could explain 35.2% of the variation in speed, and when hitting towards the deuce court timing from the end of
retraction to ball contact explained 33.6% of ball speed. The results show that there are differences in technique between the badminton jump smash and the tennis serves especially
in the first half of the sporting actions
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Radiology education in Europe: Analysis of results from 22 European countries.
AimTo assess the state of radiology education across Europe by means of a survey study.MethodsA comprehensive 23-item radiology survey was distributed via email to the International Society of Radiology members, national radiological societies, radiologists and medical physicists. Reminders to complete the survey were sent and the results were analyzed over a period of 4 mo (January-April 2016). Survey questions include length of medical school and residency training; availability of fellowship and subspecialty training; number of residency programs in each country; accreditation pathways; research training; and medical physics education. Descriptive statistics were used to analyze and summarize data.ResultsRadiology residency training ranges from 2-6 years with a median of 5 years, and follows 1 year of internship training in 55% (12 out of 22) European countries. Subspecialty fellowship training is offered in 55% (12 out of 22) European countries. Availability for specialization training by national societies is limited to eight countries. For nearly all respondents, less than fifty percent of radiologists travel abroad for specialization. Nine of 22 (41%) European countries have research requirements during residency. The types of certifying exam show variation where 64% (14 out of 22) European countries require both written and oral boards, 23% (5 out of 22) require oral examinations only, and 5% (1 out of 22) require written examinations only. A degree in medical physics is offered in 59% (13 out of 22) European countries and is predominantly taught by medical physicists. Nearly all respondents report that formal examinations in medical physics are required.ConclusionComparative learning experiences across the continent will help guide the development of comprehensive yet pragmatic infrastructures for radiology education and collaborations in radiology education worldwide
The impacts of future climate change and sulphur emission reductions on acidification recovery at Plastic Lake, Ontario
International audienceClimate-induced drought events have a significant influence on sulphate export from forested catchments in central Ontario, subsequently delaying the recovery of surface waters from acidification. In the current study, a model chain that employed a statistical downscaling model, a hydrological model and two hydrochemical models was used to forecast the chemical recovery of Plastic Lake sub-catchment 1 (PC1) from acidification under proposed deposition reductions and the A2 emission scenario of the Intergovernmental Panel on Climate Change. Any predicted recovery in stream acid neutralising capacity and pH owing to deposition reductions were clearly offset by large acid effluxes from climate-induced drought events. By 2100, ANC is predicted to show large variations ranging between 10 and ?30 ?molc L?1. Similarly, predicted pH in 2100 is lower (>0.05 of a pH unit) than the value simulated for 2000 (pH 4.35). Despite emission reductions, the future scenario paints a bleak picture of reacidification at PC1 to levels commensurate with those of the late 1970s. The principal process behind this reacidification is the oxidation of previously stored (reduced) sulphur compounds in wetlands during periods of low-flow (or drought), with subsequent efflux of sulphate upon re-wetting. Simulated catchment runoff under the A2 emissions scenario predictes increased intensity and frequency of low-flow events from approximately 2030 onwards. The Integrated Catchments model for Carbon indicated that stream DOC concentrations at PC1 will also increase under the future climate scenario, with temperature being the principal driver. Despite the predicted (significant) increase in DOC, pH is not predicted to further decline (beyond the climate-induced oxidation scenario), instead pH shows greater variability throughout the simulation. As echoed by many recent studies, hydrochemical models and model frameworks need to incorporate the drivers and mechanisms (at appropriate time-scales) that affect the key biogeochemical processes to reliably predict the impacts of climate change
Reactive Oxygen Species and Oxidative Stress in the Pathogenesis of MAFLD
The pathogenesis of metabolic-associated fatty liver disease (MAFLD) is complex and thought to be dependent on multiple parallel hits on a background of genetic susceptibility. The evidence suggests that MAFLD progression is a dynamic two-way process relating to repetitive bouts of metabolic stress and inflammation interspersed with endogenous anti-inflammatory reparative responses. In MAFLD, excessive hepatic lipid accumulation causes the production of lipotoxins that induce mitochondrial dysfunction, endoplasmic reticular stress, and over production of reactive oxygen species (ROS). Models of MAFLD show marked disruption of mitochondrial function and reduced oxidative capacitance with impact on cellular processes including mitophagy, oxidative phosphorylation, and mitochondrial biogenesis. In excess, ROS modify insulin and innate immune signaling and alter the expression and activity of essential enzymes involved in lipid homeostasis. ROS can also cause direct damage to intracellular structures causing hepatocyte injury and death. In select cases, the use of anti-oxidants and ROS scavengers have been shown to diminish the pro-apoptopic effects of fatty acids. Given this link, endogenous anti-oxidant pathways have been a target of interest, with Nrf2 activation showing a reduction in oxidative stress and inflammation in models of MAFLD. Thyroid hormone receptor β (THRβ) agonists and nuclear peroxisome proliferation-activated receptor (PPAR) family have also gained interest in reducing hepatic lipotoxicity and restoring hepatic function in models of MAFLD. Unfortunately, the true interplay between the clinical and molecular components of MAFLD progression remain only partly understood. Most recently, multiomics-based strategies are being adopted for hypothesis-free analysis of the molecular changes in MAFLD. Transcriptome profiling maps the unique genotype-phenotype associations in MAFLD and with various single-cell transcriptome-based projects underway, there is hope of novel physiological insights to MAFLD progression and uncover therapeutic targets
Advances and Emerging Therapies in the Treatment of Non-alcoholic Steatohepatitis
Non-alcoholic steatohepatitis (NASH) now represents one of the most prevalent forms of cirrhosis and hepatocellular carcinoma. A number of treatment agents have undergone assessment in humans following promising results in animal models. Currently, about 50 therapeutic agents are in various stages of development. Recently, however, there have been a number of exciting and positive developments in this landscape, although there are inherent challenges ahead. In this article, we review the aetiological and pathological basis of NASH progression and describe putative targets for current therapies. We also discuss some of the likely future directions and difficulties around this complex and challenging disease paradigm
Temperature-dependent rate coefficients for the reactions of the hydroxyl radical with the atmospheric biogenics isoprene, alpha-pinene and delta-3-carene
Pulsed laser methods for OH generation and detection were used to study atmospheric degradation reactions for three important biogenic gases: OHCisoprene (Reaction R1), OH+α-pinene (Reaction R2) and OH+Δ- 3-carene (Reaction R3). Gas-phase rate coefficients were characterized by non-Arrhenius kinetics for all three reactions. For (R1), k1 (241-356 K)= (1:93±0:08)× 10-11 exp{(466±12)/T} cm3 molecule-1 s-1 was determined, with a room temperature value of k1 (297 K)= (9:3± 0:4)×10-11 cm3 molecule-1 s-1, independent of bath-gas pressure (5-200 Torr) and composition (MDN2 or air). Accuracy and precision were enhanced by online optical monitoring of isoprene, with absolute concentrations obtained via an absorption cross section, αisoprene = (1:28±0:06)× 10-17 cm2 molecule-1 at λ = 184:95 nm, determined in this work. These results indicate that significant discrepancies between previous absolute and relative-rate determinations of k1 result in part from σ values used to derive the isoprene concentration in high-precision absolute determinations. Similar methods were used to determine rate coefficients (in 10-11 cm3 molecule-1 s-1/ for (R2)-(R3): k2 (238-357 K)= (1:83±0:04) ×exp{(330±6)/T } and k3 (235-357 K)= (2:48±0:14) ×exp{(357±17)/T }. This is the first temperature-dependent dataset for (R3) and enables the calculation of reliable atmospheric lifetimes with respect to OH removal for e.g. boreal forest springtime conditions. Room temperature values of k2 (296 K)= (5:4±0:2) ×10-11 cm3 molecule-1 s-1 and k3 (297 K)= (8:1±0:3)×10-11 cm3 molecule-1 s-1 were independent of bathgas pressure (7-200 Torr, N2 or air) and in good agreement with previously reported values. In the course of this work, 184.95 nm absorption cross sections were determined: σ = (1:54±0:08) ×10-17 cm2 molecule-1 for α-pinene and (2:40±0:12)×10-17 cm2 molecule-1 for 1-3-carene
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