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An examination of knowledge prioritisation in secondary physical education teacher education courses
A number of terms have been used to describe knowledge needed for teaching, one of which is subject knowledge. How knowledge for teaching is conceptualised in teacher education prioritises some knowledge bases over other knowledge bases. Further, knowledge prioritised by student teachers is influenced by socialisation prior to and during an initial teacher education course and priorities for student teachers as they develop as teachers. Previous research in physical education teacher education points to the pre-eminence of content knowledge above other knowledge bases. The purpose of this study was to look at what knowledge is prioritised by student teachers, school-based mentors and university tutors working on three secondary physical education initial teacher education courses in England. Results showed that content knowledge was seen as having greater importance for student teachers and mentors, but university tutors generally conceptualised subject knowledge more broadly, suggesting that it should be seen as covering a number of knowledge bases needed for teaching. These results are discussed in relation to socialisation processes in education and phases of development. Although there is a clear physical education focus to this work, it is possible that student teachers learning to teach other subjects may also focus excessively on subject content knowledge above other knowledge bases
Quantifying fusion born ion populations in magnetically confined plasmas using ion cyclotron emission
Ion cyclotron emission (ICE) offers unique promise as a diagnostic of the
fusion born alpha-particle population in magnetically confined plasmas.
Pioneering observations from JET and TFTR found that ICE intensity
scales approximately linearly with the measured neutron flux from fusion
reactions, and with the inferred concentration, , of fusion-born
alpha-particles confined within the plasma. We present fully nonlinear
self-consistent kinetic simulations that reproduce this scaling for the first
time. This resolves a longstanding question in the physics of fusion
alpha-particle confinement and stability in MCF plasmas. It confirms the
magnetoacoustic cyclotron instability (MCI) as the likely emission mechanism
and greatly strengthens the basis for diagnostic exploitation of ICE in future
burning plasmas
A Solution Merging Heuristic for the Steiner Problem in Graphs Using Tree Decompositions
Fixed parameter tractable algorithms for bounded treewidth are known to exist
for a wide class of graph optimization problems. While most research in this
area has been focused on exact algorithms, it is hard to find decompositions of
treewidth sufficiently small to make these al- gorithms fast enough for
practical use. Consequently, tree decomposition based algorithms have limited
applicability to large scale optimization. However, by first reducing the input
graph so that a small width tree decomposition can be found, we can harness the
power of tree decomposi- tion based techniques in a heuristic algorithm, usable
on graphs of much larger treewidth than would be tractable to solve exactly. We
propose a solution merging heuristic to the Steiner Tree Problem that applies
this idea. Standard local search heuristics provide a natural way to generate
subgraphs with lower treewidth than the original instance, and subse- quently
we extract an improved solution by solving the instance induced by this
subgraph. As such the fixed parameter tractable algorithm be- comes an
efficient tool for our solution merging heuristic. For a large class of sparse
benchmark instances the algorithm is able to find small width tree
decompositions on the union of generated solutions. Subsequently it can often
improve on the generated solutions fast
Omental Vascularized Lymph Node Flap: A Radiographic Analysis
BackgroundâVascularized lymph node transfer is an increasingly popular option for the treatment of lymphedema. The omental donor site is advantageous for its copious soft tissue, well-defined collateral circulation, and large number of available nodes, without the risk of iatrogenic lymphedema. The purpose of this study is to define the anatomy of the omental flap in the context of vascularized lymph node harvest.
MethodsâConsecutive abdominal computed tomography angiography (CTA) images performed at a single institution over a 1-year period were reviewed. Right gastroepiploic artery (RGEA) length, artery caliber, lymph node size, and lymph node location in relation to the artery were recorded. A two-tailed Z-test was used to compare means. A Gaussian Mixture Model confirmed by normalized entropy criterion was used to calculate three-dimensional lymph node cluster locations along the RGEA.
ResultsâIn total, 156 CTA images met inclusion criteria. The RGEA caliber at its origin was significantly larger in males compared with females (pâ<â0.001). An average of 3.1 (1.7) lymph nodes were present per patient. There was no significant gender difference in the number of lymph nodes identified. Average lymph node size was significantly larger in males (4.9 [1.9]âĂâ3.3 [0.6] mm in males vs. 4.5 [1.5]âĂâ3.1 [0.5] mm in females; pâ<â0.001). Three distinct anatomical variations of the RGEA course were noted, each with a distinct lymph node clustering pattern. Total lymph node number and size did not differ among anatomical subgroups.
ConclusionâThe omentum is a reliable lymph node donor site with consistent anatomy. This study serves as an aid in preoperative planning for vascularized lymph node transfer using the omental flap
Exponential complexity of an adiabatic algorithm for an NP-complete problem
We prove an analytical expression for the size of the gap between the ground
and the first excited state of quantum adiabatic algorithm for the
3-satisfiability, where the initial Hamiltonian is a projector on the subspace
complementary to the ground state. For large problem sizes the gap decreases
exponentially and as a consequence the required running time is also
exponential.Comment: 5 pages, 2 figures; v3. published versio
Streamlining the walls of an empty two-dimensional flexible-walled test section
The techniques used to find aerodynamically straight wall contours in a test section of a transonic wind tunnel are discussed. The walls were defined as aerodynamically straight up to Mach 0.9
Fragmentation of Nuclei at Intermediate and High Energies in Modified Cascade Model
The process of nuclear multifragmentation has been implemented, together with
evaporation and fission channels of the disintegration of excited remnants in
nucleus-nucleus collisions using percolation theory and the intranuclear
cascade model. Colliding nuclei are treated as face--centered--cubic lattices
with nucleons occupying the nodes of the lattice. The site--bond percolation
model is used. The code can be applied for calculation of the fragmentation of
nuclei in spallation and multifragmentation reactions.Comment: 19 pages, 10 figure
Detector and Telescope Development for ProtoEXIST and Fine Beam Measurements of Spectral Response of CZT Detectors
We outline our plan to develop ProtoEXIST, a balloon-borne prototype
experiment for the Energetic X-ray Imaging Survey Telescope (EXIST) for the
Black Hole Finder Probe. EXIST will consist of multiple wide-field hard X-ray
coded-aperture telescopes. The current design of the EXIST mission employs two
types of telescope systems: high energy telescopes (HETs) using CZT detectors,
and low energy telescopes (LETs) using Si detectors. With ProtoEXIST, we will
develop and demonstrate the technologies required for the EXIST HETs. As part
of our development efforts, we also present recent laboratory measurements of
the spectral response and efficiency variation of imaging CZT detectors on a
fine scale (~0.5 mm). The preliminary results confirm the need for multi-pixel
readouts and small inter-pixel gaps to achieve uniform spectral response and
high detection efficiency across detectors.Comment: 9 pages, 12 figures, 1 table, appears in SPIE 2005 proceedings (5898:
UV, X-ray, and Gamma-ray Space Instrumentation for Astronomy XIV
Stability and collapse of rapidly rotating, supramassive neutron stars: 3D simulations in general relativity
We perform 3D numerical simulations in full general relativity to study the
stability of rapidly rotating, supramassive neutron stars at the mass-shedding
limit to dynamical collapse. We adopt an adiabatic equation of state with
and focus on uniformly rotating stars. We find that the onset of
dynamical instability along mass-shedding sequences nearly coincides with the
onset of secular instability. Unstable stars collapse to rotating black holes
within about one rotation period. We also study the collapse of stable stars
which have been destabilized by pressure depletion (e.g. via a phase
transition) or mass accretion. In no case do we find evidence for the formation
of massive disks or any ejecta around the newly formed Kerr black holes, even
though the progenitors are rapidly rotating.Comment: 16 pages, to appear in Phys. Rev.
Functional Unit of the RNA Polymerase II C-Terminal Domain Lies within Heptapeptide PairsĂâĂÂ
Unlike all other RNA polymerases, the largest subunit (RPB1) of eukaryotic DNA-dependent RNA polymerase II (RNAP II) has a C-terminal domain (CTD) comprising tandemly repeated heptapeptides with the consensus sequence Y-S-P-T-S-P-S. The tandem structure, heptad consensus, and most key functions of the CTD are conserved between yeast and mammals. In fact, all metazoans, fungi, and green plants examined to date, as well as the nearest protistan relatives of these multicellular groups, contain a tandemly repeated CTD. In contrast, the RNAP II largest subunits from many other eukaryotic organisms have a highly degenerate C terminus or show no semblance of the CTD whatsoever. The reasons for intense stabilizing selection on CTD structure in certain eukaryotes, and its apparent absence in others, are unknown. Here we demonstrate, through in vivo genetic complementation, that the essential functional unit of the yeast CTD is contained within pairs of heptapeptides. Insertion of a single alanine residue between diheptads has little phenotypic effect, while increasing the distance between diheptads produces a mostly quantitative effect on yeast cell growth. We further explore structural constraints on the CTD within an evolutionary context and propose selective mechanisms that could maintain a global tandem structure across hundreds of millions of years of eukaryotic evolution. Originally published Eukaryotic Cell, Vol. 3, No. 3, June 200
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