464 research outputs found
Does Mckuer's Law Hold for Heart Rate Control via Biofeedback Display?
Some persons can control their pulse rate with the aid of a biofeedback display. If the biofeedback display is modified to show the error between a command pulse-rate and the measured rate, a compensatory (error correcting) heart rate tracking control loop can be created. The dynamic response characteristics of this control loop when subjected to step and quasi-random disturbances were measured. The control loop includes a beat-to-beat cardiotachmeter differenced with a forcing function from a quasi-random input generator; the resulting error pulse-rate is displayed as feedback. The subject acts to null the displayed pulse-rate error, thereby closing a compensatory control loop. McRuer's Law should hold for this case. A few subjects already skilled in voluntary pulse-rate control were tested for heart-rate control response. Control-law properties are derived, such as: crossover frequency, stability margins, and closed-loop bandwidth. These are evaluated for a range of forcing functions and for step as well as random disturbances
For the greater good: how long-term ministries benefit Unitarian Universalism
Unitarian Universalist congregations suffer from short-term ministries, requiring focus on transition rather than faith development and congregational vision. This thesis suggests that long-term ministries are advantageous, and explores factors contributing to effective long-term ministries. The method was to interview clergy serving eight or more years in congregations and following other long-term ministers. Interviewees were then brought into dialogue with leadership theory, theology, and past studies of the topic. The analysis reveals benefits for Unitarian Universalist long-term ministries, including increased stability, trust, vision, resilience, and spiritual maturity. The thesis concludes with proposals to support long-term ministries more widely in Unitarian Universalism
How the Mustang trampled the Luftwaffe: the role of the P-51 in the defeat of the German air force in World War Two
The purposes of this study were to trace the evolution of the North American P-51 Mustang as an escort fighter in World War Two and to enumerate the reasons why it played a leading role in the extension of the American strategic bombing campaign into Germany and the ultimate defeat of the German Luftwaffe. The Mustang prototype was built in 1940 in response to a British request for a fighter to help repel German invaders. The original model, powered by an Allison engine and three-bladed propeller, was fast and maneuverable at low altitudes, but its performance deteriorated rapidly at altitudes above 12,000 feet. In an experiment to improve its high-altitude performance, the British installed a Rolls Royce Merlin engine in the Mustang, and the resulting high altitude performance of the airplane was exceptional. However, at that time neither the British nor the Americans opted to pursue further development and production of the airplane. After America entered the war following the Japanese attack on Pearl Harbor in 1941, the Allied powers agreed that the main war effort should be to Defeat Germany First. A principal aspect of the war plan was a daylight strategic bombing campaign against German forces in Continental Europe by American bombers. The bombing campaign from bases in England began in July of 1942. As the program progressed and targets were attacked that were beyond the range of escorting Allied fighters, it became apparent that the bombers could not adequately defend themselves against defending German fighters. A desperate effort was made to develop a high-performance escort fighter that could accompany the bombers to all targets of interest. The Merlin-powered Mustang with a four-bladed propeller proved to be that airplane. This thesis discusses the technical reasons why the Mustang was a superior escort and air combat fighter. The energy maneuverability analysis is used to explain how the fighter gained an air combat advantage over the principal Luftwaffe fighter aircraft. The roles of bomber escort doctrine, pilot training and aircraft production in bringing the Mustang into its position of superiority are also indicated
Use of Clearview Gel Dosimeter for Quality Assurance and Testing of Stereotactic Radiosurgery
There exists a lack of accurate, reproducible three-dimensional dosimetry techniques for stereotactic radiosurgery (SRS) commissioning and quality assurance. This experiment evaluates the use of ClearView gel dosimeters as an alternative to current methods for small field dosimetry in SRS testing. ClearView differs from other gel dosimeters in that it uses tetrazolium salt in its chemical make-up in place of traditional Fricke-type compounds. Using a Varian TrueBeam radiotherapy system to deliver the radiation, three vials of ClearView gel dosimeter were tested in three different dose delivery scenarios. The first test examined the dosimeter\u27s response to a static beam with the dose isocenter targeted to the centroid of the vial. The second evaluation consisted of a full rotational SRS delivery about the center of the dosimeter. Lastly, a complete end-to-end treatment plan was performed to evaluate the accuracy of the dosimeter in a full SRS procedure. The three dosimeters were then scanned to measure the dose distribution throughout the gel. Finally, the resulting data was compared to the initial treatment plan to determine the accuracy of the gel. According to the comparisons performed, the ClearView gel showed capability of sub-millimeter spatial accuracy across the three evaluations, with a maximum geometric uncertainty of 1.2 mm. Based on these results, ClearView gel shows promise for possible use in SRS dosimetry applications in clinical settings
Systems and methods for measuring component matching
Systems and methods for measuring a contour match between adjacent components are disclosed. In one embodiment, at least two pressure sensors are located between adjacent components. Each pressure sensor is adapted to obtain a pressure measurement at a location a predetermined distance away from the other pressure sensors, and to output a pressure measurement for each sensor location. An output device is adapted to receive the pressure measurements from at least two pressure sensors and display the pressure measurements. In one aspect, the pressure sensors include flexible thin film pressure sensors. In accordance with other aspects of the invention, a method is provided for measuring a contour match between two interfacing components including measuring at least one pressure applied to at least one sensor between the interfacing components
A spatio-temporal comparison of avian migration phenology using Citizen Science data
The effects of climate change have wide-ranging impacts on wildlife species and recent studies indicate that birds’ spring arrival dates are advancing in response to changes in global climates. In this paper, we propose a spatio-temporal approach for comparing avian first arrival data for multiple species. As an example, we analyze spring arrival data for two long-distance migrants (Rubythroated Hummingbird Archilochus colubris; and Purple Martin Progne subis) in eastern North America from 2001–2010 using Citizen Science data. The proposed approach provides researchers with a tool to compare mean arrival dates while accounting for spatial and temporal variability. Our results show that on average, Purple Martins arrive 29.95 to 31.84 days earlier than Ruby-throated Hummingbirds, but after accounting for this overall difference, spatial nuances exist whereby martins arrive earlier in the southern United States and migrate northward at a slower rate than hummingbirds. Differences were also noted in how climate and weather variables such as the North Atlantic Oscillation index, winter temperature, winter–spring precipitation, sampling effort, and altitude impacted migration dates. Our method may easily be generalized to analyze a broad range of temporal and spatial Citizen Scientists data to help better understand the ecological impacts of climate change
Combining mobile-health (mHealth) and artificial intelligence (AI) methods to avoid suicide attempts: the Smartcrises study protocol
The screening of digital footprint for clinical purposes relies on the capacity of wearable technologies
to collect data and extract relevant information’s for patient management. Artificial intelligence (AI) techniques
allow processing of real-time observational information and continuously learning from data to build
understanding. We designed a system able to get clinical sense from digital footprints based on the smartphone’s
native sensors and advanced machine learning and signal processing techniques in order to identify suicide risk.
Method/design: The Smartcrisis study is a cross-national comparative study. The study goal is to determine the
relationship between suicide risk and changes in sleep quality and disturbed appetite. Outpatients from the
Hospital Fundación Jiménez DÃaz Psychiatry Department (Madrid, Spain) and the University Hospital of Nimes
(France) will be proposed to participate to the study. Two smartphone applications and a wearable armband will
be used to capture the data. In the intervention group, a smartphone application (MEmind) will allow for the
ecological momentary assessment (EMA) data capture related with sleep, appetite and suicide ideations.
Discussion: Some concerns regarding data security might be raised. Our system complies with the highest level of
security regarding patients’ data. Several important ethical considerations related to EMA method must also be
considered. EMA methods entails a non-negligible time commitment on behalf of the participants. EMA rely on
daily, or sometimes more frequent, Smartphone notifications. Furthermore, recording participants’ daily experiences
in a continuous manner is an integral part of EMA. This approach may be significantly more than asking a
participant to complete a retrospective questionnaire but also more accurate in terms of symptoms monitoring.
Overall, we believe that Smartcrises could participate to a paradigm shift from the traditional identification of risks
factors to personalized prevention strategies tailored to characteristics for each patientThis study was partly funded by Fundación Jiménez DÃaz Hospital, Instituto
de Salud Carlos III (PI16/01852), Delegación del Gobierno para el Plan
Nacional de Drogas (20151073), American Foundation for Suicide Prevention
(AFSP) (LSRG-1-005-16), the Madrid Regional Government (B2017/BMD-3740
AGES-CM 2CM; Y2018/TCS-4705 PRACTICO-CM) and Structural Funds of the
European Union. MINECO/FEDER (‘ADVENTURE’, id. TEC2015–69868-C2–1-R)
and MCIU Explora Grant ‘aMBITION’ (id. TEC2017–92552-EXP), the French Embassy
in Madrid, Spain, The foundation de l’avenir, and the Fondation de
France. The work of D. RamÃrez and A. Artés-RodrÃguez has been partly supported
by Ministerio de EconomÃa of Spain under projects: OTOSIS
(TEC2013–41718-R), AID (TEC2014–62194-EXP) and the COMONSENS Network
(TEC2015–69648-REDC), by the Ministerio de EconomÃa of Spain jointly with
the European Commission (ERDF) under projects ADVENTURE (TEC2015–
69868-C2–1-R) and CAIMAN (TEC2017–86921-C2–2-R), and by the Comunidad
de Madrid under project CASI-CAM-CM (S2013/ICE-2845). The work of P.
Moreno-Muñoz has been supported by FPI grant BES-2016-07762
Boeing: Arc Jet Exposure of Ablative Non-Oxide CMC TPS for Planetary Probe and Sample Return Applications
NASA Game Changing Development (GCD) provided Boeing support under a Space Act Agreement (SAA) for arc jet sample design, CFD support and arc jet test time of stagnation and shear models for 3 Boeing TPS materials: BLA (Boeing Lightweight Ablator, 18, 21 and 22 densities), BPA (Boeing Phenolic Ablator, standard, graded density, or without reinforcement) and Non-oxide high temperature ceramic composite for structurally integrated TPS (SITPS). Results: For BLA, tested successfully to 500 W/cm heat flux and heat loads up to 12 kJ/cm with shear loads up to 370 Pa. The BPA 2017 formulation tested successfully to 1500 W/cm and 80 kJ/cm, with shear loads up to 250 Pa. For SITIPS, Boeing fabricated C/SiC laminate materials survived testing in shear
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