24,087 research outputs found
Collaborative concept mapping: an education research team leveraging their collaborative efforts
Collaborative concept mapping (CCM) has been a tool deployed by educators to enhance learning in such situations as primary science classes, supported learning environments and asynchronous computer-mediated learning. Of its outcomes, CCM has produced rich group discussion about ideas and possibilities pertinent to the topic or problem at hand. The majority of research into CCM has been explicitly pointed at enhancing learning. This chapter takes a different tack by reporting on how the authors used CCM to seek understandings of its utility in enabling collaborative research by creating synergies within a research team located in the Faculty of Education at the University of Southern Queensland. The following questions were used to focus the research:
• What was the research team’s experience of collaborative concept mapping?
• What propositions did the team construct about teamwork and collaboration?
• How did the interactions among team members facilitate meaning-making about teamwork and collaboration?
The data consisted of this team’s collaborative concept map and recordings of the dialogue during the process of constructing the map. Analysis revealed the team’s emerging propositions about teamwork and collaboration and also contributed understandings of the co-constructed patterns of talk that produced this dynamic map. The chapter concludes that collaborative concept mapping is a useful tool for research and other team development, and possibly for the collaborative conceptualisation of future team research projects
Asymmetries of Heavy Elements in the Young Supernova Remnant Cassiopeia A
Supernova remnants (SNRs) offer the means to study supernovae (SNe) long
after the original explosion and can provide a unique insight into the
mechanism that governs these energetic events. In this work, we examine the
morphologies of X-ray emission from different elements found in the youngest
known core-collapse (CC) SNR in the Milky Way, Cassiopeia A. The heaviest
elements exhibit the highest levels of asymmetry, which we relate to the
burning process that created the elements and their proximity to the center of
explosion. Our findings support recent model predictions that the material
closest to the source of explosion will reflect the asymmetries inherent to the
SN mechanism. Additionally, we find that the heaviest elements are moving more
directly opposed to the neutron star (NS) than the lighter elements. This
result is consistent with NS kicks arising from ejecta asymmetries.Comment: 12 pages, 4 figures, 2 tables Updated to include an analysis of
Emission Measure Maps (vs the, still-included, continuum-subtracted flux
maps), used as another proxy for mass maps. The results have not changed; the
emission measure maps also show increasing asymmetry with ejecta mass. (Now
matches the version published in ApJ. Vol 889 Issue 2 (2020) 144
Scintillator-based ion beam profiler for diagnosing laser-accelerated ion beams
Next generation intense, short-pulse laser facilities require new high repetition rate diagnostics for the detection of ionizing radiation. We have designed a new scintillator-based ion beam profiler capable of measuring the ion beam transverse profile for a number of discrete energy ranges. The optical response and emission characteristics of four common plastic scintillators has been investigated for a range of proton energies and fluxes. The scintillator light output (for 1 MeV > Ep < 28 MeV) was found to have a non-linear scaling with proton energy but a linear response to incident flux. Initial measurements with a prototype diagnostic have been successful, although further calibration work is required to characterize the total system response and limitations under the high flux, short pulse duration conditions of a typical high intensity laser-plasma interaction
Torque control system
System stabilizes aximuth of gondolas which are carried by high-altitude balloons as platforms for tracking telescopes. When telescopes must be constantly aimed at specific targets, control system stabilizes gondola to within 5 arc-seconds
Application of numerical methods to planetary radiowave scattering
Existing numerical techniques for the solution of scattering problems were investigated to determine those which might be applicable to planetary surface studies, with the goal of improving the interpretation of radar data from Venus, Mars, the Moon, and icy satellites. The general characteristics of the models are described along with computational concerns. In particular, the Numerical Electrogmatics Code (NEC) developed at the Lawrence Livermore Laboratory is discussed. Though not developed for random rough surfaces, the NEC contains elements which may be generalized and which could be valuable in the study of scattering by planetary surfaces
Surface properties of Galilean satellites from bistatic radar experiments
The icy moons of Jupiter were the first to show unusual radar backscatter behavior in Earth-based experiments. Studies of Europa, Ganymede, and Callisto revealed strong echoes and a reversed sense of circular polarization. No explanations were entirely satisfactory because of the difficult constraints imposed by the existing data. The (scalar) bidirectional coherence model predicts an opposition effect, or enhancement in the backscatter direction, resulting from coherent addition of backscatter from identical (but oppositely directed) ray paths. The mode decoupling model yields a similar, vector result in which the observed polarization properties of the backscattered wave can also be obtained. The possibilities were considered for conducting such experiments using the Galileo spacecraft. Both conventional oblique-forward bistatic experiments (to determine basic electrical and physical properties of the surface material on centimeter-meter scales) and near-backscatter experiments (to sample the enhanced backscatter lobe) were considered
Carfentrazone-ethyl Pond Dissipation and Efficacy on Floating Plants
Carfentrazone-ethyl (CE) is a reduced risk herbicide that
is currently being evaluated for the control of aquatic weeds.
Greenhouse trials were conducted to determine efficacy of
CE on water hyacinth (
Eichhornia crassipes
(Mart.) Solms-
Laub.), water lettuce (
Pistia stratiotes
L.), salvinia (
Salvinia
minima
Baker) and landoltia
(Landoltia punctata
(G. Mey.)
Les & D. J. Crawford
)
. CE controlled water lettuce, water hyacinth
and salvinia at rates less than the maximum proposed
use rate of 224 g ha
-1
. Water lettuce was the most susceptible
to CE with an EC
90
of 26.9 and 33.0 g ha
-1
in two separate trials.
Water hyacinth EC
90
values were calculated to be 86.2 to
116.3 g ha
-1
, and salvinia had a similar susceptibility to water
hyacinth with an EC
90
of 79.1 g ha
-1
. Landoltia was not adequately
controlled at the rates evaluated. In addition, CE was
applied to one-half of a 0.08 ha pond located in North Central,
Florida to determine dissipation rates in water and hydrosoil
when applied at an equivalent rate of 224 g ha
-1
. The
half-life of CE plus the primary metabolite, CE-chloropropionic
acid, was calculated to be 83.0 h from the whole pond,
and no residues were detected in water above the limit of
quantification (5 ÎĽg L
-1
) 168 h after treatment. CE dissipated
rapidly from the water column, did not occur in the sediment
above the levels of quantification, and in greenhouse
studies effectively controlled three species of aquatic weeds
at relatively low rates.(PDF contains 6 pages.
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