932 research outputs found

    Ion mass spectrometer for special uses

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    Prototype of curved-electrode, Paul-type, quadrupole, electrodynamic mass filter has the mass-resolution and transmission-factor properties expected from both theoretical considerations and results of experiments using linear quadrupole features

    Observations of cross-shelf flow driven by cross-shelf winds on the inner continental shelf

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    Author Posting. © American Meteorological Society, 2008. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 38 (2008): 2358-2378, doi:10.1175/2008JPO3990.1.Six-yr-long time series of winds, waves, and water velocity from a cabled coastal observatory in 12 m of water reveal the separate dependence of the cross-shelf velocity profile on cross-shelf and along-shelf winds, waves, and tides. During small waves, cross-shelf wind is the dominant mechanism driving the cross-shelf circulation after tides and tidal residual motions are removed. The along-shelf wind does not drive a substantial cross-shelf circulation. During offshore winds, the cross-shelf circulation is offshore in the upper water column and onshore in the lower water column, with roughly equal and opposite volume transports in the surface and bottom layers. During onshore winds, the circulation is nearly the reverse. The observed profiles and cross-shelf transport in the surface layer during winter agree with a simple two-dimensional unstratified model of cross-shelf wind stress forcing. The cross-shelf velocity profile is more vertically sheared and the surface layer transport is stronger in summer than in winter for a given offshore wind stress. During large waves, the cross-shelf circulation is no longer roughly symmetric in the wind direction. For onshore winds, the cross-shelf velocity profile is nearly vertically uniform, because the wind- and wave-driven shears cancel; for offshore winds, the profile is strongly vertically sheared because the wind- and wave-driven shears have the same sign. The Lagrangian velocity profile in winter is similar to the part of the Eulerian velocity profile due to cross-shelf wind stress alone, because the contribution of Stokes drift to the Lagrangian velocity approximately cancels the contribution of waves to the Eulerian velocity.This research was funded by the Ocean Sciences Division of the National Science Foundation under Grants OCE-0241292 and OCE-0548961 and by National Aeronautics and Space Administration Headquarters under Grant NNG04GL03G and the Earth System Science Fellowship Grant NNG04GQ14H. MVCO is partly funded by the Woods Hole Oceanographic Institution and the Jewett/EDUC/Harrison Foundation

    Modular Unmanned Aerial System with Multi-Mode Propulsion

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    A modular Unmanned Aerial System (UAS) includes an Unmanned Aerial Vehicle (UAV) parent module and UAV child modules. A main wing extends from a respective fuselage of the modules. The UAS includes docking mechanisms coupled to wingtips of the main wings. The child modules dock with the wingtips of the parent or an adjacent child module. Docking forms a linked-flight configuration, with undocking and separation from the parent or adjacent child module achieving an independent-flight configuration. The modules have booms arranged transverse to the main wings and parallel to the longitudinal axis, as well as front and rear rotors/propellers. The front and rear propellers have axes of rotation that are normal to a plane of the longitudinal axis in a vertical takeoff and landing (VTOL) configuration, with the axis of rotation of the rear propellers parallel to the longitudinal axis in a forward-flight configuration

    Hogwash: Coming to Terms with Critical Race Theory in Adult Education

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    Today’s adult and community education classrooms and sites of practice are increasingly diverse. As adult educators, we have a responsibility to appropriately meet each student at their level of need. Critical race theory provides a non-hegemonic lens for understanding and meeting the needs of our diverse student population

    Observations and a model of undertow over the inner continental shelf

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    Author Posting. © American Meteorological Society, 2008. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 38 (2008): 2341-2357, doi:10.1175/2008JPO3986.1.Onshore volume transport (Stokes drift) due to surface gravity waves propagating toward the beach can result in a compensating Eulerian offshore flow in the surf zone referred to as undertow. Observed offshore flows indicate that wave-driven undertow extends well offshore of the surf zone, over the inner shelves of Martha’s Vineyard, Massachusetts, and North Carolina. Theoretical estimates of the wave-driven offshore transport from linear wave theory and observed wave characteristics account for 50% or more of the observed offshore transport variance in water depths between 5 and 12 m, and reproduce the observed dependence on wave height and water depth. During weak winds, wave-driven cross-shelf velocity profiles over the inner shelf have maximum offshore flow (1–6 cm s−1) and vertical shear near the surface and weak flow and shear in the lower half of the water column. The observed offshore flow profiles do not resemble the parabolic profiles with maximum flow at middepth observed within the surf zone. Instead, the vertical structure is similar to the Stokes drift velocity profile but with the opposite direction. This vertical structure is consistent with a dynamical balance between the Coriolis force associated with the offshore flow and an along-shelf “Hasselmann wave stress” due to the influence of the earth’s rotation on surface gravity waves. The close agreement between the observed and modeled profiles provides compelling evidence for the importance of the Hasselmann wave stress in forcing oceanic flows. Summer profiles are more vertically sheared than either winter profiles or model profiles, for reasons that remain unclear.This research was funded by the Ocean Sciences Division of the National Science Foundation under Grants OCE-0241292 and OCE-0548961

    Learning in an Introductory Physics MOOC: All Cohorts Learn Equally, Including an On-Campus Class

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    We studied student learning in the MOOC 8.MReV Mechanics ReView, run on the edX.org open source platform. We studied learning in two ways. We administered 13 conceptual questions both before and after instruction, analyzing the results using standard techniques for pre- and posttesting. We also analyzed each week’s homework and test questions in the MOOC, including the pre- and posttests, using item response theory (IRT). This determined both an average ability and a relative improvement in ability over the course. The pre- and posttesting showed substantial learning: The students had a normalized gain slightly higher than typical values for a traditional course, but significantly lower than typical values for courses using interactive engagement pedagogy. Importantly, both the normalized gain and the IRT analysis of pre- and posttests showed that learning was the same for different cohorts selected on various criteria: level of education, preparation in math and physics, and overall ability in the course. We found a small positive correlation between relative improvement and prior educational attainment. We also compared homework performance of MIT freshmen taking a reformed on-campus course with the 8.MReV students, finding them to be considerably less skillful than the 8.MReV students.Google (Firm) (Faculty Award)Massachusetts Institute of TechnologyNational Science Foundation (U.S.

    Desperately seeking fixedness: practitioners accounts of 'becoming doctoral researchers

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    We draw upon the concept of liminality to explore the experiences of practitioners enrolled on a UK Doctor of Business Administration (DBA) programme. We analyse twenty practitioners’ reflective journals to detail how the DBA liminal space was negotiated. More specifically, we describe how practitioners deal with their struggles of identity incoherence or ‘monsters of doubt’ which are amplified in the DBA context owing to the complex nature of the separation phase of liminality. We identify three broad methods deployed in this endeavour: ‘scaffolding’; ‘putting the past to work’ and ‘bracketing’- which evidence practitioners ‘desperately seeking fixedness’. We make three contributions – first, we provide empirical insights into the experiences of the increasingly significant, but still under researched, DBA student. Second, we develop our understandings of monsters of doubt through illustrating how these are negotiated for learning to progress. Finally, we contribute to wider discussions of ‘becoming’ to demonstrate the simultaneous and paradoxical importance of movement and fixedness in order to learn and become

    Audit of the autoantibody test, EarlyCDTÂź-Lung, in 1600 patients: An evaluation of its performance in routine clinical practice

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    ObjectivesEarlyCDT¼-Lung may enhance detection of early stage lung cancer by aiding physicians in assessing high-risk patients through measurement of biological markers (i.e., autoantibodies). The test's performance characteristics in routine clinical practice were evaluated by auditing clinical outcomes of 1613 US patients deemed at high risk for lung cancer by their physician, who ordered the EarlyCDT-Lung test for their patient.MethodsClinical outcomes for all 1613 patients who provided HIPAA authorization are reported. Clinical data were collected from each patient's treating physician. Pathology reports when available were reviewed for diagnostic classification. Staging was assessed on histology, otherwise on imaging.ResultsSix month follow-up for the positives/negatives was 99%/93%. Sixty-one patients (4%) were identified with lung cancer, 25 of whom tested positive by EarlyCDT-Lung (sensitivity = 41%). A positive EarlyCDT-Lung test on the current panel was associated with a 5.4-fold increase in lung cancer incidence versus a negative. Importantly, 57% (8/14) of non-small cell lung cancers detected as positive (where stage was known) were stage I or II.ConclusionsEarlyCDT-Lung has been extensively tested and validated in case–control settings and has now been shown in this audit to perform in routine clinical practice as predicted. EarlyCDT-Lung may be a complementary tool to CT for detection of early lung cancer

    A systematic review of parent and family functioning in pediatric solid organ transplant populations

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    The process of pediatric solid organ transplantation (SOT) places new and increased stressors on patients and family members. Measures of family functioning may predict psychological and health outcomes for pediatric patients and their families, and provide opportunity for targeted intervention. This systematic review investigated parent and family functioning and factors associated with poorer functioning in the pediatric SOT population. Thirty‐seven studies were identified and reviewed. Studies featured a range of organ populations (eg, heart, liver, kidney, lung, intestine) at various stages in the transplant process. Findings highlighted that parents of pediatric SOT populations commonly report increased stress and mental health symptoms, including posttraumatic stress disorder. Pediatric SOT is also associated with increased family stress and burden throughout the transplant process. Measures of parent and family functioning were associated with several important health‐related factors, such as medication adherence, readiness for discharge, and number of hospitalizations. Overall, findings suggest that family stress and burden persists post‐transplant, and parent and family functioning is associated with health‐related factors in SOT, highlighting family‐level functioning as an important target for future intervention.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136483/1/petr12900.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136483/2/petr12900_am.pd
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