2,359 research outputs found
A narrative review of adaptive testing and its application to medical education.
Adaptive testing has a long but largely unrecognized history. The advent of computer-based testing has created new opportunities to incorporate adaptive testing into conventional programmes of study. Relatively recently software has been developed that can automate the delivery of summative assessments that adapt by difficulty or content. Both types of adaptive testing require a large item bank that has been suitably quality assured. Adaptive testing by difficulty enables more reliable evaluation of individual candidate performance, although at the expense of transparency in decision making, and requiring unidirectional navigation. Adaptive testing by content enables reduction in compensation and targeted individual support to enable assurance of performance in all the required outcomes, although at the expense of discovery learning. With both types of adaptive testing, candidates are presented a different set of items to each other, and there is the potential for that to be perceived as unfair. However, when candidates of different abilities receive the same items, they may receive too many they can answer with ease, or too many that are too difficult to answer. Both situations may be considered unfair as neither provides the opportunity to demonstrate what they know. Adapting by difficulty addresses this. Similarly, when everyone is presented with the same items, but answer different items incorrectly, not providing individualized support and opportunity to demonstrate performance in all the required outcomes by revisiting content previously answered incorrectly could also be considered unfair; a point addressed when adapting by content. We review the educational rationale behind the evolution of adaptive testing and consider its inherent strengths and limitations. We explore the continuous pursuit of improvement of examination methodology and how software can facilitate personalized assessment. We highlight how this can serve as a catalyst for learning and refinement of curricula; fostering engagement of learner and educator alike
Temporal and between-site variation in helminth communities of bank voles (Myodes glareolus) from N.E. Poland: 2. The infracommunity level
The relative importance of temporal and spatial effects was assessed in helminth communities of bank voles (Myodes glareolus) in 3 woodland sites in N.E. Poland in the late summers of 1999 and 2002. Among common species the rank order of sites in relation to prevalence and abundance of infection was maintained between surveys. Site effects accounted for most of the deviance (in statistical models), and time was less important, so the exact location from which voles were sampled was of critical importance. The only exception was Syphacia petrusewiczi. In contrast, for derived measures such as species richness and diversity, most deviance was accounted for by host age, and the interaction between site and year was significant, implying that rank order of sites changed between years. Temporal effects on derived measures were generated primarily by a combination of relatively small changes in prevalence and abundance of the common, rather than the rare, species between the years of the study. In the medium-term, therefore, helminth communities of bank voles in N.E. Poland had a stable core, suggesting a substantial strong element of predictability
Estimation of Hydrodynamical Model Parameters from the Invariant Spectrum and the Bose-Einstein Correlations of pi-mesons Produced in (pi+/K+)p Interactions at 250 GeV/c
The invariant spectra of pi- mesons produced in (pi+/K+)p interactions at 250
GeV/c are analysed in the framework of the hydrodynamical model of
three-dimensionally expanding cylindrically symmetric finite systems.
A satisfactory description of experimental data is achieved.
The data favour the pattern according to which the hadron matter undergoes
predominantly longitudinal expansion and non-relativistic transverse expansion
with mean transverse velocity = 0.20(7), and is characterized by a large
temperature inhomogeneity in the transverse direction: the extracted freeze-out
temperature at the center of the tube and at the transverse rms radius are
140(3) MeV and 82(7) MeV, respectively. The width of the (longitudinal)
space-time rapidity distribution of the pion source is found to be Delta eta =
1.36(2).
Combining this estimate with results of the Bose-Einstein correlation
analysis in the same experiment, one extracts a mean freeze-out time of the
source of = 1.4(1) fm/c and its transverse geometrical rms radius, R_G
(rms)=1.2(2) fm.Comment: latex, 14 pages, 5 figure
Dialkyldithiophosphate Acids (HDDPs) as Effective Lubricants of Sol–Gel Titania Coatings in Technical Dry Friction Conditions
The goal of this study was the investigation of
the effectiveness of dialkyldithiophosphate acids (HDDPs)
films in improving the tribological properties of thin, sol–
gel derived titania coatings. Amorphous, anatase, and rutile
titania coatings were obtained using sol–gel dip–coating
deposition after treatment at 100, 500, and 1,000 C,
respectively. Titania coatings were then modified from the
liquid phase by HDDPs acids having dodecyl-(C12), tetradecyl-(C14),
and hexadecyl-(C16) alkyl chains deposited by
dip–coating (DC) and Langmuir–Blodgett (LB) methods.
The influence of the deposition procedure, the length of the
HDDPs alkyl chain and the type of titania substrate on the
surface morphology and tribological properties were studied.
It was found, using wetting contact angle measurements,
that these modifications of titania coatings decrease
the surface free energy and increase its hydrophobicity.
The surface topography imaged by Atomic force microscopy
(AFM), exhibit island-like or agglomerate features for
the DC deposition method, while smooth topographies
were observed for LB depositions. Tribological tests were
conducted by means of a microtribometer operating in the
normal load range 30–100 mN. An enhancement of tribological
properties was observed upon modification, as
compared to unmodified titania
Temporal and between-site variation in helminth communities of bank voles (Myodes glareolus) from N.E. Poland. 1. Regional fauna and component community levels
Helminth infections were studied in bank voles (Myodes glareolus) from 3 woodland sites in N.E. Poland in the late summers of 1999 and 2002, to assess the temporal stability of derived statistics describing the regional helminth fauna and component community structure, and spatial influence on the latter. Regional helminth fauna changed dramatically between the two years, primarily due to a fall in the abundance of Syphacia petrusewiczi but was partially compensated for by an increase in Mesocestoides lineatus and Cladotaenia globifera. It was dominated by nematodes overall, but more so in 1999 than in 2002 when larval cestodes were more frequent. Most derived parameters for component community structure varied considerably between sites and the two surveys, the hierarchical order for sites not being maintained between surveys. They were susceptible to the disproportionate influence of three relatively rare, unpredictable species with the greatest overall aggregated distribution among hosts. Jaccard’s similarity index was less influenced by the rare species, showing greater stability between sites and across years. In conclusion, temporal variation confounded any site-specific characteristics of the summary measures quantified in this study and their usefulness is therefore restricted to the years in which the surveys were conducted
J-PET: a new technology for the whole-body PET imaging
The Jagiellonian Positron Emission Tomograph (J-PET) is the first PET built
from plastic scintillators. J-PET prototype consists of 192 detection modules
arranged axially in three layers forming a cylindrical diagnostic chamber with
the inner diameter of 85 cm and the axial field-of-view of 50 cm. An axial
arrangement of long strips of plastic scintillators, their small light
attenuation, superior timing properties, and relative ease of the increase of
the axial field-of-view opens promising perspectives for the cost effective
construction of the whole-body PET scanner, as well as construction of MR and
CT compatible PET inserts. Present status of the development of the J-PET
tomograph will be presented and discussed.Comment: Presented at the 2nd Jagiellonian Symposium on Fundamental and
Applied Subatomic Physics, Krak\'ow, Poland, June 4-9, 2017. To be published
in Acta Phys. Pol.
Three-dimensional image reconstruction in J-PET using Filtered Back Projection method
We present a method and preliminary results of the image reconstruction in
the Jagiellonian PET tomograph. Using GATE (Geant4 Application for Tomographic
Emission), interactions of the 511 keV photons with a cylindrical detector were
generated. Pairs of such photons, flying back-to-back, originate from e+e-
annihilations inside a 1-mm spherical source. Spatial and temporal coordinates
of hits were smeared using experimental resolutions of the detector. We
incorporated the algorithm of the 3D Filtered Back Projection, implemented in
the STIR and TomoPy software packages, which differ in approximation methods.
Consistent results for the Point Spread Functions of ~5/7,mm and ~9/20, mm were
obtained, using STIR, for transverse and longitudinal directions, respectively,
with no time of flight information included.Comment: Presented at the 2nd Jagiellonian Symposium on Fundamental and
Applied Subatomic Physics, Krak\'ow, Poland, June 4-9, 2017. To be published
in Acta Phys. Pol.
Commissioning of the J-PET detector for studies of decays of positronium atoms
The Jagiellonian Positron Emission Tomograph (J-PET) is a detector for
medical imaging of the whole human body as well as for physics studies
involving detection of electron-positron annihilation into photons. J-PET has
high angular and time resolution and allows for measurement of spin of the
positronium and the momenta and polarization vectors of annihilation quanta. In
this article, we present the potential of the J-PET system for background
rejection in the decays of positronium atoms.Comment: Presented at the 2nd Jagiellonian Symposium on Fundamental and
Applied Subatomic Physics, Krak\'ow, Poland, June 4-9, 2017. To be published
in Acta Phys. Pol.
Measurement of the Luminosity in the ZEUS Experiment at HERA II
The luminosity in the ZEUS detector was measured using photons from electron
bremsstrahlung. In 2001 the HERA collider was upgraded for operation at higher
luminosity. At the same time the luminosity-measuring system of the ZEUS
experiment was modified to tackle the expected higher photon rate and
synchrotron radiation. The existing lead-scintillator calorimeter was equipped
with radiation hard scintillator tiles and shielded against synchrotron
radiation. In addition, a magnetic spectrometer was installed to measure the
luminosity independently using photons converted in the beam-pipe exit window.
The redundancy provided a reliable and robust luminosity determination with a
systematic uncertainty of 1.7%. The experimental setup, the techniques used for
luminosity determination and the estimate of the systematic uncertainty are
reported.Comment: 25 pages, 11 figure
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