342 research outputs found

    Training and Transfer Effect of FluoroSim, an Augmented Reality Fluoroscopic Simulator for Dynamic Hip Screw Guidewire Insertion: A Single-Blinded Randomized Controlled Trial

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    BACKGROUND: FluoroSim, a novel fluoroscopic simulator, can be used to practice dynamic hip screw (DHS) guidewire insertion in a high-fidelity clinical scenario. Our aim was to demonstrate a training effect in undergraduate medical students who are not familiar with this operation and its simulation. METHODS: Forty-five undergraduate medical students were recruited and randomized to either training (n = 23) or control (n = 22) cohorts. The training cohort had more exposure to FluoroSim (5 attempts each week) over a 2-week period (with a 1-week washout period in between) compared with the control cohort (a single attempt 1 week apart) over a 2-week period. Five real-time objective performance metrics were recorded: (1) tip-apex distance (TAD) (mm), (2) predicted cut-out rate (%), (3) total procedural time (sec), (4) total number of radiographs (n), and (5) total number of guidewire retries (n). RESULTS: At baseline, there was no significant difference in the performance metrics, which confirmed the absence of a selection bias. The intragroup training effect demonstrated a significant improvement in all metrics for the training cohort only. A significant difference between groups was demonstrated as the training cohort significantly outperformed the control cohort in 3 metrics (procedural time [25%], number of radiographs [57%], and number of guidewire retries [100%]; p < 0.001). A learning curve showed an inversely proportional correlation between frequency of attempts and procedural time as well as the number of digital fluoroscopic radiographs that were made, indicating the development of psychomotor skills. There was also an improved baseline of the learning curve after the 1-week washout period, suggesting skill retention. CONCLUSIONS: Skill acquisition with the FluoroSim system was demonstrated with repeat exposure in a safe, radiation-free high-fidelity clinical simulation with actual operating room equipment. The task of DHS guidewire insertion requires cognitive and psychomotor skills that take a variable number of attempts to acquire, as demonstrated on the learning curve. Additional work is required to demonstrate that the skill tested by the FluoroSim is the same skill that is required for intraoperative DHS guidewire insertion. However, use of the FluoroSim provides improvement in skills with extra-clinical training opportunities for orthopaedic trainees. CLINICAL RELEVANCE: FluoroSim has demonstrated validity and training effect. It has the potential to be approved for possible use on patients in the operating room to help surgeons with the operation. Consequently, operating time, accuracy of TAD, and surgical outcomes may all be improved

    An evaluation of Sea Search as a citizen science programme in Marine Protected Areas

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    Citizen science involves collaboration between multi-sector agencies and the public to address a natural resource management issue. The Sea Search citizen science programme involves community groups in monitoring and collecting subtidal rocky reef and intertidal rocky shore data in Victorian Marine Protected Areas (MPAs), Australia. In this study we compared volunteer and scientifically collected data and the volunteer motivation for participation in the Sea Search programme. Intertidal rocky shore volunteer-collected data was found to be typically comparable to data collected by scientists for species richness and diversity measures. For subtidal monitoring there was also no significant difference for species richness recorded by scientists and volunteers. However, low statistical power suggest only large changes could be detected due to reduced data replication. Generally volunteers recorded lower species diversity for biological groups compared to scientists, albeit not significant. Species abundance measures for algae species were significantly different between volunteers and scientists. These results suggest difficulty in identification and abundance measurements by volunteers and the need for additional training requirements necessary for surveying algae assemblages. The subtidal monitoring results also highlight the difficulties of collecting data in exposed rocky reef habitats with weather conditions and volunteer diver availability constraining sampling effort. The prime motivation for volunteer participation in Sea Search was to assist with scientific research followed closely by wanting to work close to nature. This study revealed two important themes for volunteer engagement in Sea Search: 1) volunteer training and participation and, 2) usability of volunteer collected data for MPA managers. Volunteer-collected data through the Sea Search citizen science programme has the potential to provide useable data to assist in informed management practices of Victoria&rsquo;s MPAs, but requires the support and commitment from all partners involved.<br /

    Teaching basic trauma: validating FluoroSim, a digital fluoroscopic simulator for guide-wire insertion in hip surgery

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    Background and purpose — Simulation is an adjunct to surgical education. However, nothing can accurately simulate fluoroscopic procedures in orthopedic trauma. Current options for training with fluoroscopy are either intraoperative, which risks radiation, or use of expensive and unrealistic virtual reality simulators. We introduce FluoroSim, an inexpensive digital fluoroscopy simulator without the need for radiation. Patients and methods — This was a multicenter study with 26 surgeons in which everyone completed 1 attempt at inserting a guide-wire into a femoral dry bone using surgical equipment and FluoroSim. 5 objective performance metrics were recorded in real-time to assess construct validity. The surgeons were categorized based on the number of dynamic hip screws (DHS) performed: novices (< 10), intermediates (10–39) and experts (≄ 40). A 7-point Likert scale questionnaire assessed the face and content validity of FluoroSim. Results — Construct validity was present for 2 clinically validated metrics in DHS surgery. Experts and intermediates statistically significantly outperformed novices for tip–apex distance and for cut-out rate. Novices took the least number of radiographs. Face and content validity were also observed. Interpretation — FluoroSim discriminated between novice and intermediate or expert surgeons based on tip–apex distance and cut-out rate while demonstrating face and content validity. FluoroSim provides a useful adjunct to orthopedic training. Our findings concur with results from studies using other simulation modalities. FluoroSim can be implemented for education easily and cheaply away from theater in a safe and controlled environment

    Investigation of initiation of gigantic jets connecting thunderclouds to the ionosphere

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    The initiation of giant electrical discharges called as "gigantic jets" connecting thunderclouds to the ionosphere is investigated by numerical simulation method in this paper. Using similarity relations, the triggering conditions of streamer formation in laboratory situations are extended to form a criterion of initiation of gigantic jets. The energy source causing a gigantic jet is considered due to the quasi-electrostatic field generated by thunderclouds. The electron dynamics from ionization threshold to streamer initiation are simulated by the Monte Carlo technique. It is found that gigantic jets are initiated at a height of ~18-24 km. This is in agreement with the observations. The method presented in this paper could be also applied to the analysis of the initiation of other discharges such as blue jets and red sprites.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004, Nice (France

    Convection and electrodynamic signatures in the vicinity of a Sun-aligned arc: Results from the Polar Acceleration Regions and Convection Study (Polar ARCS)

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    An experimental campaign designed to study high-latitude auroral arcs was conducted in Sondre Stromfjord, Greenland, on February 26, 1987. The Polar Acceleration Regions and Convection Study (Polar ARCS) consisted of a coordinated set of ground-based, airborne, and sounding rocket measurements of a weak, sun-aligned arc system within the duskside polar cap. A rocket-borne barium release experiment, two DMSP satellite overflights, all-sky photography, and incoherent scatter radar measurements provided information on the large-scale plasma convection over the polar cap region while a second rocket instrumented with a DC magnetometer, Langmuir and electric field probes, and an electron spectrometer provided measurements of small-scale electrodynamics. The large-scale data indicate that small, sun-aligned precipitation events formed within a region of antisunward convection between the duskside auroral oval and a large sun-aligned arc further poleward. This convection signature, used to assess the relationship of the sun-aligned arc to the large-scale magnetospheric configuration, is found to be consistent with either a model in which the arc formed on open field lines on the dusk side of a bifurcated polar cap or on closed field lines threading an expanded low-latitude boundary layer, but not a model in which the polar cap arc field lines map to an expanded plasma sheet. The antisunward convection signature may also be explained by a model in which the polar cap arc formed on long field lines recently reconnected through a highly skewed plasma sheet. The small-scale measurements indicate the rocket passed through three narrow (less than 20 km) regions of low-energy (less than 100 eV) electron precipitation in which the electric and magnetic field perturbations were well correlated. These precipitation events are shown to be associated with regions of downward Poynting flux and small-scale upward and downward field-aligned currents of 1-2 micro-A/sq m. The paired field-aligned currents are associated with velocity shears (higher and lower speed streams) embedded in the region of antisunward flow

    First E region observations of mesoscale neutral wind interaction with auroral arcs

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    We report the first observations of E region neutral wind fields and their interaction with auroral arcs at mesoscale spatial resolution during geomagnetically quiet conditions at Mawson, Antarctica. This was achieved by using a scanning Doppler imager, which can observe thermospheric neutral line-of-sight winds and temperatures simultaneously over a wide field of view. In two cases, the background E region wind field was perpendicular to an auroral arc, which when it appeared caused the wind direction within ∌50 km of the arc to rotate parallel along the arc, reverting to the background flow direction when the arc disappeared. This was observed under both westward and eastward plasma convection. The wind rotations occurred within 7–16 min. In one case, as an auroral arc propagated from the horizon toward the local zenith, the background E region wind field became significantly weaker but remained unaffected where the arc had not passed through. We demonstrate through modeling that these effects cannot be explained by height changes in the emission layer. The most likely explanation seems to be the greatly enhanced ion drag associated with the increased plasma density and localized ionospheric electric field associated with auroral arcs. In all cases, the F region neutral wind appeared less affected by the auroral arc, although its presence is clear in the data

    MiL Testing of Highly Configurable Continuous Controllers: Scalable Search Using Surrogate Models

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    Continuous controllers have been widely used in automotive do- main to monitor and control physical components. These con- trollers are subject to three rounds of testing: Model-in-the-Loop (MiL), Software-in-the-Loop and Hardware-in-the-Loop. In our earlier work, we used meta-heuristic search to automate MiL test- ing of fixed configurations of continuous controllers. In this paper, we extend our work to support MiL testing of all feasible configura- tions of continuous controllers. Specifically, we use a combination of dimensionality reduction and surrogate modeling techniques to scale our earlier MiL testing approach to large, multi-dimensional input spaces formed by configuration parameters. We evaluated our approach by applying it to a complex, industrial continuous controller. Our experiment shows that our approach identifies test cases indicating requirements violations. Further, we demonstrate that dimensionally reduction helps generate surrogate models with higher prediction accuracy. Finally, we show that combining our search algorithm with surrogate modelling improves its efficiency for two out of three requirements

    Integral cross sections for electron scattering by ground state Ba atoms

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    We have used the convergent close-coupling method and a unitarized first-order many-body theory to calculate integral cross sections for elastic scattering and momentum transfer, for excitation of the 5d^2 ^1S, 6s6p^1P_1, 6s7p^1P_1, 6s8p^1P_1, 6s5d^1D_2, 5d^2^1D_2, 6s6d^1D_2, 6p5d^1F_3, 6s4f^1F_3, 6p5d^1D_2, 6s6p^3P_{0,1,2}, 6s5d^3D_{1,2,3}, and 6p5d^3D_2 states, for ionization and for total scattering by electron impact on the ground state of barium at incident electron energies from 1 to 1000 eV. These results and all available experimental data have been combined to produce a recommended set of integral cross sections.Comment: 47 pages, 8 tables, 25 figure

    Belle II Technical Design Report

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    The Belle detector at the KEKB electron-positron collider has collected almost 1 billion Y(4S) events in its decade of operation. Super-KEKB, an upgrade of KEKB is under construction, to increase the luminosity by two orders of magnitude during a three-year shutdown, with an ultimate goal of 8E35 /cm^2 /s luminosity. To exploit the increased luminosity, an upgrade of the Belle detector has been proposed. A new international collaboration Belle-II, is being formed. The Technical Design Report presents physics motivation, basic methods of the accelerator upgrade, as well as key improvements of the detector.Comment: Edited by: Z. Dole\v{z}al and S. Un
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