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  1. Article ; Online: Exploring assessor cognition as a source of score variability in a performance assessment of practice-based competencies

    Mary Roduta Roberts / Megan Cook / Iris C. I. Chao

    BMC Medical Education, Vol 20, Iss 1, Pp 1-

    2020  Volume 14

    Abstract: Abstract Background A common feature of performance assessments is the use of human assessors to render judgements on student performance. From a measurement perspective, variability among assessors when assessing students may be viewed as a concern ... ...

    Abstract Abstract Background A common feature of performance assessments is the use of human assessors to render judgements on student performance. From a measurement perspective, variability among assessors when assessing students may be viewed as a concern because it negatively impacts score reliability and validity. However, from a contextual perspective, variability among assessors is considered both meaningful and expected. A qualitative examination of assessor cognition when assessing student performance can assist in exploring what components are amenable to improvement through enhanced rater training, and the extent of variability when viewing assessors as contributing their individual expertise. Therefore, the purpose of this study was to explore assessor cognition as a source of score variability in a performance assessment of practice-based competencies. Method A mixed-method sequential explanatory study design was used where findings from the qualitative strand assisted in the interpretation of results from the quantitative strand. Scores from one objective structured clinical examination (OSCE) were obtained for 95 occupational therapy students. Two Generalizability studies were conducted to examine the relative contribution of assessors as a source of score variability and to estimate the reliability of domain and holistic scores. Think-aloud interviews were conducted with eight participants assessing a subset of student performances from the OSCE in which they participated. Findings from the analysis of think-aloud data and consideration of assessors’ background characteristics were used to assist in the interpretation of variance component estimates involving assessors, and score reliability. Results Results from two generalizability analyses indicated the highest-order interaction-error term involving assessors accounted for the second-highest proportion of variance, after student variation. Score reliability was higher in the holistic vs. analytic scoring framework. Verbal analysis of assessors' think-aloud interviews provided evidential support for the quantitative results. Conclusions This study provides insight into the nature and extent of assessor variability during a performance assessment of practice-based competencies. Study findings are interpretable from the measurement and contextual perspectives on assessor cognition. An integrated understanding is important to elucidate the meaning underlying the numerical score because the defensibility of inferences made about students’ proficiencies rely on score quality, which in turn relies on expert judgements.
    Keywords Assessor cognition ; Generalizability theory ; Mixed method ; Occupational therapy ; OSCE ; Performance assessment ; Special aspects of education ; LC8-6691 ; Medicine ; R
    Subject code 420 ; 780
    Language English
    Publishing date 2020-05-01T00:00:00Z
    Publisher BMC
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: The nature of Pu-bearing particles from the Maralinga nuclear testing site, Australia

    Megan Cook / Barbara Etschmann / Rahul Ram / Konstantin Ignatyev / Gediminas Gervinskas / Steven D. Conradson / Susan Cumberland / Vanessa N. L. Wong / Joёl Brugger

    Scientific Reports, Vol 11, Iss 1, Pp 1-

    2021  Volume 12

    Abstract: Abstract The high-energy release of plutonium (Pu) and uranium (U) during the Maralinga nuclear trials (1955–1963) in Australia, designed to simulate high temperature, non-critical nuclear accidents, resulted in wide dispersion µm-sized, radioactive, Pu– ... ...

    Abstract Abstract The high-energy release of plutonium (Pu) and uranium (U) during the Maralinga nuclear trials (1955–1963) in Australia, designed to simulate high temperature, non-critical nuclear accidents, resulted in wide dispersion µm-sized, radioactive, Pu–U-bearing ‘hot’ particles that persist in soils. By combining non-destructive, multi-technique synchrotron-based micro-characterization with the first nano-scale imagining of the composition and textures of six Maralinga particles, we find that all particles display intricate physical and chemical make-ups consistent with formation via condensation and cooling of polymetallic melts (immiscible Fe–Al–Pu–U; and Pb ± Pu–U) within the detonation plumes. Plutonium and U are present predominantly in micro- to nano-particulate forms, and most hot particles contain low valence Pu–U–C compounds; these chemically reactive phases are protected by their inclusion in metallic alloys. Plutonium reworking was observed within an oxidised rim in a Pb-rich particle; however overall Pu remained immobile in the studied particles, while small-scale oxidation and mobility of U is widespread. It is notoriously difficult to predict the long-term environmental behaviour of hot particles. Nano-scale characterization of the hot particles suggests that long-term, slow release of Pu from the hot particles may take place via a range of chemical and physical processes, likely contributing to on-going Pu uptake by wildlife at Maralinga.
    Keywords Medicine ; R ; Science ; Q
    Subject code 660
    Language English
    Publishing date 2021-05-01T00:00:00Z
    Publisher Nature Portfolio
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article: Comparison of radium-228 determination in water among Australian laboratories

    Zawadzki, Atun / Alicea Gedz / Brodie Cutmore / Daniela Fierro / Fiona Evans / Jennifer J. Harrison / Lida Mokhber-Shahin / Megan Cook / Peter Medley / Sandra Sdraulig / Sarah Mullins / Tom Loosz

    Journal of environmental radioactivity. 2017 Nov., v. 178-179

    2017  

    Abstract: The National Health and Medical Research Council and Natural Resource Management Ministerial Council of Australia developed the current Australian Drinking Water Guidelines which recommend an annual radiation dose value of 1 mSv year−1. One of the ... ...

    Abstract The National Health and Medical Research Council and Natural Resource Management Ministerial Council of Australia developed the current Australian Drinking Water Guidelines which recommend an annual radiation dose value of 1 mSv year−1. One of the potential major contributors to the radiation dose from drinking water is radium-228, a naturally occurring radionuclide arising from the thorium decay series. Various methods of analysing for radium-228 in water have been established and adapted by analytical radiochemistry laboratories. Seven laboratories in Australia participated in analysing radium-228 spiked water samples with activity concentrations ranging from 6 mBq L−1 to 20 Bq L−1. The aim of the exercise was to compare and evaluate radium-228 results reported by the participating laboratories, the methods used and the detection limits. This paper presents the outcome of the exercise.
    Keywords drinking water ; exercise ; radioactivity ; radionuclides ; radium ; thorium ; Australia
    Language English
    Dates of publication 2017-11
    Size p. 411-418.
    Publishing place Elsevier Ltd
    Document type Article
    ZDB-ID 1483112-0
    ISSN 1879-1700 ; 0265-931X
    ISSN (online) 1879-1700
    ISSN 0265-931X
    DOI 10.1016/j.jenvrad.2017.05.012
    Database NAL-Catalogue (AGRICOLA)

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  4. Article ; Online: iPSCORE

    Athanasia D. Panopoulos / Matteo D'Antonio / Paola Benaglio / Roy Williams / Sherin I. Hashem / Bernhard M. Schuldt / Christopher DeBoever / Angelo D. Arias / Melvin Garcia / Bradley C. Nelson / Olivier Harismendy / David A. Jakubosky / Margaret K.R. Donovan / William W. Greenwald / KathyJean Farnam / Megan Cook / Victor Borja / Carl A. Miller / Jonathan D. Grinstein /
    Frauke Drees / Jonathan Okubo / Kenneth E. Diffenderfer / Yuriko Hishida / Veronica Modesto / Carl T. Dargitz / Rachel Feiring / Chang Zhao / Aitor Aguirre / Thomas J. McGarry / Hiroko Matsui / He Li / Joaquin Reyna / Fangwen Rao / Daniel T. O'Connor / Gene W. Yeo / Sylvia M. Evans / Neil C. Chi / Kristen Jepsen / Naoki Nariai / Franz-Josef Müller / Lawrence S.B. Goldstein / Juan Carlos Izpisua Belmonte / Eric Adler / Jeanne F. Loring / W. Travis Berggren / Agnieszka D'Antonio-Chronowska / Erin N. Smith / Kelly A. Frazer

    Stem Cell Reports, Vol 8, Iss 4, Pp 1086-

    A Resource of 222 iPSC Lines Enabling Functional Characterization of Genetic Variation across a Variety of Cell Types

    2017  Volume 1100

    Abstract: Summary: Large-scale collections of induced pluripotent stem cells (iPSCs) could serve as powerful model systems for examining how genetic variation affects biology and disease. Here we describe the iPSCORE resource: a collection of systematically ... ...

    Abstract Summary: Large-scale collections of induced pluripotent stem cells (iPSCs) could serve as powerful model systems for examining how genetic variation affects biology and disease. Here we describe the iPSCORE resource: a collection of systematically derived and characterized iPSC lines from 222 ethnically diverse individuals that allows for both familial and association-based genetic studies. iPSCORE lines are pluripotent with high genomic integrity (no or low numbers of somatic copy-number variants) as determined using high-throughput RNA-sequencing and genotyping arrays, respectively. Using iPSCs from a family of individuals, we show that iPSC-derived cardiomyocytes demonstrate gene expression patterns that cluster by genetic background, and can be used to examine variants associated with physiological and disease phenotypes. The iPSCORE collection contains representative individuals for risk and non-risk alleles for 95% of SNPs associated with human phenotypes through genome-wide association studies. Our study demonstrates the utility of iPSCORE for examining how genetic variants influence molecular and physiological traits in iPSCs and derived cell lines. : Working as part of the NHLBI NextGen consortium, Panopoulos and colleagues report the derivation and characterization of 222 publicly available iPSCs from ethnically diverse individuals with corresponding genomic data including SNP arrays, RNA-seq, and whole-genome sequencing. This collection provides a powerful resource to investigate the function of genetic variants. Keywords: iPSCORE, iPSC, GWAS, molecular traits, physiological traits, cardiac disease, NHLBI Next Gen, LQT2, KCNH2, iPSC-derived cardiomyocytes
    Keywords Medicine (General) ; R5-920 ; Biology (General) ; QH301-705.5
    Subject code 616
    Language English
    Publishing date 2017-04-01T00:00:00Z
    Publisher Elsevier
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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