4,734 research outputs found
Editorial "special issue on educational design research (EDR) in post-secondary learning environments
Along with many ASCILITE members, we have grown increasingly concerned that current approaches to educational technology research lack value and practical application in the field. Educational design research (EDR) is an emerging approach that bridges the demand for rigorous research with the development of relevant solutions to educational problems. EDR is an intervention and process-oriented approach that uses a variety of methods to examine the development and implementation of instructional solutions to current educational problems. As evidence about the inner workings of interventions accumulates over time, design principles and learning theories are derived from work in local contexts, and their limits can be tested in other settings. This genre of research is currently underrepresented in the literature. To advance scholarship through the execution and reporting of EDR, we identified an urgent need for examples across fields, and especially related to educational technology in higher education.
The purpose of this special issue is to advance the field by showcasing exemplars of high quality EDR in post-secondary educational settings. We have sought manuscripts that detail EDR projects involving the use and/or development of educational technology in tertiary education (higher and further), lifelong learning, and training. This manuscript set therefore promotes research and scholarship on innovative instructional designs that integrate technology in those settings, promote effective practice, and help inform policy
Evaluation of Vascular Control Mechanisms Utilizing Video Microscopy of Isolated Resistance Arteries of Rats
This protocol describes the use of in vitro television microscopy to evaluate vascular function in isolated cerebral resistance arteries (and other vessels), and describes techniques for evaluating tissue perfusion using Laser Doppler Flowmetry (LDF) and microvessel density utilizing fluorescently labeled Griffonia simplicifolia (GS1) lectin. Current methods for studying isolated resistance arteries at transmural pressures encountered in vivo and in the absence of parenchymal cell influences provide a critical link between in vivo studies and information gained from molecular reductionist approaches that provide limited insight into integrative responses at the whole animal level. LDF and techniques to selectively identify arterioles and capillaries with fluorescently-labeled GS1 lectin provide practical solutions to enable investigators to extend the knowledge gained from studies of isolated resistance arteries. This paper describes the application of these techniques to gain fundamental knowledge of vascular physiology and pathology in the rat as a general experimental model, and in a variety of specialized genetically engineered designer rat strains that can provide important insight into the influence of specific genes on important vascular phenotypes. Utilizing these valuable experimental approaches in rat strains developed by selective breeding strategies and new technologies for producing gene knockout models in the rat, will expand the rigor of scientific premises developed in knockout mouse models and extend that knowledge to a more relevant animal model, with a well understood physiological background and suitability for physiological studies because of its larger size
The impact of volcanic aerosol on the Northern Hemisphere stratospheric polar vortex: mechanisms and sensitivity to forcing structure
Observations and simple theoretical arguments suggest that the Northern Hemisphere (NH) stratospheric polar vortex is stronger in winters following major volcanic eruptions. However, recent studies show that climate models forced by prescribed volcanic aerosol fields fail to reproduce this effect. We investigate the impact of volcanic aerosol forcing on stratospheric dynamics, including the strength of the NH polar vortex, in ensemble simulations with the Max Planck Institute Earth System Model. The model is forced by four different prescribed forcing sets representing the radiative properties of stratospheric aerosol following the 1991 eruption of Mt. Pinatubo: two forcing sets are based on observations, and are commonly used in climate model simulations, and two forcing sets are constructed based on coupled aerosolâclimate model simulations. For all forcings, we find that simulated temperature and zonal wind anomalies in the NH high latitudes are not directly impacted by anomalous volcanic aerosol heating. Instead, high-latitude effects result from enhancements in stratospheric residual circulation, which in turn result, at least in part, from enhanced stratospheric wave activity. High-latitude effects are therefore much less robust than would be expected if they were the direct result of aerosol heating. Both observation-based forcing sets result in insignificant changes in vortex strength. For the model-based forcing sets, the vortex response is found to be sensitive to the structure of the forcing, with one forcing set leading to significant strengthening of the polar vortex in rough agreement with observation-based expectations. Differences in the dynamical response to the forcing sets imply that reproducing the polar vortex responses to past eruptions, or predicting the response to future eruptions, depends on accurate representation of the spaceâtime structure of the volcanic aerosol forcing
Here or There Instruction: Lessons Learned in Implementing Innovative Approaches to Blended Synchronous Learning
Here or There (HOT) instruction is a blended synchronous approach that enables students from on-campus (âhereâ) or a remote location (âthereâ) to participate together in class activities in real time. The purpose of this article is to share three different cases at two universities that illustrate different implementations of HOT instruction, explain the affordances of these varied approaches, provide best practices that are common to each, and share lessons learned along the way. Readers will gain a better understanding of how to implement a range of innovative HOT approaches, and in what context(s) they might choose one approach over another. The authorsâ experience indicates that sound pedagogical principles along with pragmatic considerations, such as class size, available technology, and instructorâs skills, should guide decisions regarding use of these blended synchronous approaches. Future research should look towards what impact
blended synchronous environments have on student outcomes
Stratosphere troposphere coupling: the influence of volcanic eruptions
Stratospheric sulfate aerosols produced by major volcanic eruptions modify the radiative and dynamical properties of the troposphere and stratosphere through their reflection of solar radiation and absorption of infrared radiation. At the Earth's surface, the primary consequence of a large eruption is cooling, however, it has long been known that major tropical eruptions tend to be followed by warmer than usual winters over the Northern Hemisphere (NH) continents. This volcanic "winter-warming" effect in the NH is understood to be the result of changes in atmospheric circulation patterns resulting from heating in the stratosphere, and is often described as positive anomalies of the Northern Annular Mode (NAM) that propagate downward from the stratosphere to the troposphere. In the southern hemisphere, climate models tend to also predict a positive Southern Annular Mode (SAM) response to volcanic eruptions, but this is generally inconsistent with post-eruption observations during the 20th century. We review present understanding of the influence of volcanic eruptions on the large scale modes of atmospheric variability in both the Northern and Southern Hemispheres. Using models of varying complexity, including an aerosol-climate model, an Earth system model, and CMIP5 simulations, we assess the ability of climate models to reproduce the observed post-eruption climatic and dynamical anomalies. We will also address the parametrization of volcanic eruptions in simulations of the past climate, and identify possibilities for improvemen
Spectrum of Neutral Helium in Strong Magnetic Fields
We present extensive and accurate calculations for the excited state spectrum
of spin-polarized neutral helium in a range of magnetic field strengths up to
G. Of considerable interest to models of magnetic white dwarf stellar
atmospheres, we also present results for the dipole strengths of the low lying
transitions among these states. Our methods rely on a systematically saturated
basis set approach to solving the Hartree--Fock self-consistent field
equations, combined with an ``exact'' stochastic method to estimate the
residual basis set truncation error and electron correlation effects. We also
discuss the applicability of the adiabatic approximation to strongly magnetized
multi-electron atoms.Comment: 19 pages, 7 figures, 10 table
Recommended from our members
Floating Platform Effects on Power Generation in Spar and Semisubmersible Wind Turbines
The design and financing of commercial-scale floating offshore wind projects require a better understanding of how power generation differs between newer floating turbines and well-established fixed-bottom turbines. In floating turbines, platform mobility causes additional rotor motion that can change the time-averaged power generation. In this work, OpenFAST simulations examine the power generated by the National Renewable Energy Laboratory\u27s 5-MW reference turbine mounted on the OC3-UMaine spar and OC4-DeepCWind semisubmersible floating platforms, subjected to extreme irregular waves and below-rated turbulent inflow wind from large-eddy simulations of a neutral atmospheric boundary layer. For these below-rated conditions, average power generation in floating turbines is most affected by two types of turbine displacements: an average rotor pitch angle that reduces power, caused by platform pitch; and rotor motion upwind-downwind that increases power, caused by platform surge and pitch. The relative balance between these two effects determines whether a floating platform causes power gains or losses compared to a fixed-bottom turbine; for example, the spar creates modest (3.1%-4.5%) power gains, whereas the semisubmersible creates insignificant (0.1%-0.2%) power gains for the simulated conditions. Furthermore, platform surge and pitch motions must be analyzed concurrently to fully capture power generation in floating turbines, which is not yet universal practice. Finally, a simple analytical model for predicting average power in floating turbines under below-rated wind speeds is proposed, incorporating effects from both the time-averaged pitch displacement and the dynamic upwind-downwind displacements
Sodium Brightening of (3200) Phaethon Near Perihelion
Sunskirting asteroid (3200) Phaethon has been repeatedly observed in STEREO
HI1 imagery to anomalously brighten and produce an antisunward tail for a few
days near each perihelion passage, phenomena previously attributed to the
ejection of micron-sized dust grains. Color imaging by the SOHO LASCO
coronagraphs during the 2022 May apparition indicate that the observed
brightening and tail development instead capture the release of sodium atoms,
which resonantly fluoresce at the 589.0/589.6 nm D lines. While HI1's design
bandpass nominally excludes the D lines, filter degradation has substantially
increased its D line sensitivity, as quantified by the brightness of Mercury's
sodium tail in HI1 imagery. Furthermore, the expected fluorescence efficiency
and acceleration of sodium atoms under solar radiation readily reproduce both
the photometric and morphological behaviors observed by LASCO and HI1 during
the 2022 apparition and the 17 earlier apparitions since 1997. This finding
connects Phaethon to the broader population of sunskirting and sungrazing
comets observed by SOHO, which often also exhibit bright sodium emission with
minimal visible dust, but distinguishes it from other sunskirting asteroids
without detectable sodium production under comparable solar heating. These
differences may reflect variations in the degree of sodium depletion of
near-surface material, and thus the extent and/or timing of any past or present
resurfacing activity.Comment: 30 pages, 14 figures, 6 tables; PSJ, in pres
Central Equatorial Pacific Cooling During the Last Glacial Maximum
Establishing tropical sea surface temperature (SST) during the Last Glacial Maximum (LGM) is important for constraining equilibrium climate sensitivity to radiative forcing. Until now, there has been little data from the central equatorial Pacific in global compilations, with foraminiferal assemblageâbased estimates suggesting the region was within 1°C of modern temperatures during the LGM. This is in stark contrast to multiâproxy evidence from the eastern and western Pacific and model simulations which support larger cooling. Here we present the first estimates of glacial SST in the central equatorial Pacific from Mg/Ca in Globigerinoides ruber. Our results show that the central Pacific cooled by about 2.0°C during the LGM, in contrast with previous global compilations but in agreement with models. Our data support a larger magnitude of tropical LGM cooling, and thus a larger equilibrium climate sensitivity, than previous studies which relied on foraminiferal assemblages in the central tropical Pacific
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