Colin Melville

Bio: Colin Melville is an academic researcher from University of Manchester. The author has contributed to research in topics: Overcrowding & Set (abstract data type). The author has an hindex of 6, co-authored 19 publications receiving 89 citations. Previous affiliations of Colin Melville include General Medical Council.

Very-short-answer questions: reliability, discrimination and acceptability

Abstract: CONTEXT: Single-best-answer questions (SBAQs) have been widely used to test knowledge because they are easy to mark and demonstrate high reliability. However, SBAQs have been criticised for being subject to cueing. OBJECTIVES: We used a novel assessment tool that facilitates efficient marking of open-ended very-short-answer questions (VSAQs). We compared VSAQs with SBAQs with regard to reliability, discrimination and student performance, and evaluated the acceptability of VSAQs. METHODS: Medical students were randomised to sit a 60-question assessment administered in either VSAQ and then SBAQ format (Group 1, n = 155) or the reverse (Group 2, n = 144). The VSAQs were delivered on a tablet; responses were computer-marked and subsequently reviewed by two examiners. The standard error of measurement (SEM) across the ability spectrum was estimated using item response theory. RESULTS: The review of machine-marked questions took an average of 1 minute, 36 seconds per question for all students. The VSAQs had high reliability (alpha: 0.91), a significantly lower SEM than the SBAQs (p < 0.001) and higher mean item-total point biserial correlations (p < 0.001). The VSAQ scores were significantly lower than the SBAQ scores (p < 0.001). The difference in scores between VSAQs and SBAQs was attenuated in Group 2. Although 80.4% of students found the VSAQs more difficult, 69.2% found them more authentic. CONCLUSIONS: The VSAQ format demonstrated high reliability and discrimination and items were perceived as more authentic. The SBAQ format was associated with significant cueing. The present results suggest the VSAQ format has a higher degree of validity.

Clinical prioritisation questions: A novel assessment tool to encourage tolerance of uncertainty?

Abstract: Uncertainty is a common and increasingly acknowledged problem in clinical practice. Current single best answer (SBA) style assessments test areas where there is one correct answer, and as the appro...

Using prescribing very short answer questions to identify sources of medication errors: a prospective study in two UK medical schools

Abstract: Objective To assess the utility and ability of the novel prescribing very short answer (VSA) question format to identify the sources of undergraduate prescribing errors when compared with the conventional single best answer (SBA) question format and assess the acceptability of machine marking prescribing VSAs. Design A prospective study involving analysis of data generated from a pilot two-part prescribing assessment. Setting Two UK medical schools. Participants 364 final year medical students took part. Participation was voluntary. There were no other inclusion or exclusion criteria. Outcomes (1) Time taken to mark and verify VSA questions (acceptability), (2) differences between VSA and SBA scores, (3) performance in VSA and (4) SBA format across different subject areas and types of prescribing error made in the VSA format. Results 18 200 prescribing VSA questions were marked and verified in 91 min. The median percentage score for the VSA test was significantly lower than the SBA test (28% vs 64%, p Conclusions Prescribing VSA questions represent an efficient tool for providing detailed insight into the sources of significant prescribing errors, which are not identified by SBA questions. This makes the prescribing VSA a valuable formative assessment tool to enhance students’ skills in safe prescribing and to potentially reduce prescribing errors.

An investigation of the alkaloids of some British species of Equisetum.

Abstract: The alkaloids nicotine and palustrine have been separated from authentic mixtures by paper partition chromatography, paper electrophoresis and the use of buffered cellulose columns. These techniques were applied to extracts of E. arvense, E. telmateia and E. sylvaticum from the last two of which no alkaloids have previously been isolated. Nicotine was found in all three species but palustrine was not detected.

Approaches to the identification of angiosperm leaf remains

Abstract: During the past 125 years the history of early angiosperms, interpreted through the fossil leaf record has been largely an exercise in paleofloristic studies, ignoring evolution. Imprecise identifications of ancient leaves “matched” to extant genera and families have been used as the basis for reconstructions of paleocommunities and paleoclimates. However, as the result of careful morphological studies of leaf form, venation and cuticular features new insights into the evolution of angiosperms are now available. In this paper considerations are given to the usefulness and shortcomings of leaf form, venation and cuticular analysis as diagnostic tools of plant identification. Many techniques for the study of the morphology of modern and fossil leaves are included in this paper as well as tables outlining features of leaf venation and the epidermis. Careful morphological studies of leaf form (such as the venation and epidermal characters emphasized in this paper) will provide better understanding of the relationships of living angiosperms and transform the fossil leaf record into useful data that can be used to study the evolution of the angiosperms.

Stratification of tropical forests as seen in leaf structure

Abstract: 1 Introduction- 2 Source of the Material and Sample Collection- 3 Preparation of Slides- 4 General Observations- Leaf morphology- Drip tip - Pulvini - Leaf size - Leaf shape - Juvenile and adult leaf forms - Venation- Innter leaf structure- Xero-, meso-, hygromorphy, and sun-, medium-, shade-leaf, alternatively - Leaf consistency - Structural peculiarities- Structure in relation to function- 5 Tables of the Families Studied Indicating Structural Characteristics- Annonaceae - Capparidaceae - Violaceae - Flacourtiaceae - Vochysiaceae - Guttiferae - Quiinaceae - Sterculiaceae - Tiliaceae - Elaeocarpaceae - Humiriaceae - Malpighiaceae - Rutaceae - Simaroubaceae - Ochnaceae - Burseraceae - Meliaceae - Dichapetalaceae - Olacaceae - Opiliaceae - Celastraceae - Sapindaceae - Sabiaceae - Anacardiaceae - Mimosaceae - Caesalpiniaceae -Papilionaceae - Rosaceae - Combretaceae - Myrtaceae - Lecythidaceae - Melastomaceae - Araliaceae - Rubiaceae - Sapotaceae - Ebenaceae - Apocynaceae - Boraginaceae - Solanaceae - Bignoniaceae - Verbenaceae -- Nyctaginaceae - Polygonaceae - Myristicaceae - Lauraceae - Euphorbiaceae - Moraceae - Lacistemaceae - Unidentified (Nigua)- 6 Description of the Families Studied Concerning Leaf Structure- Annonaceae - Capparidaceae - Violaceae - Flacourtiaceae - Vochysiaceae - Guttiferae - Sterculiaceae - Tiliaceae - Elaeocarpaceae - Malpighiaceae - Rutaceae - Simaroubaceae - Ochnaceae - Burseraceae - Meliaceae - Dichapetalaceae - Opiliaceae - Celastraceae - Sapindaceae - Sabiaceae - Anacardiaceae - Mimosaceae - Caesalpiniaceae - Papilionaceae - Rosaceae - Combretaceae - Myrtaceae - Lecythidaceae - Melastomaceae - Rubiaceae - Sapotaceae - Ebenaceae - Apocynaceae - Boraginaceae - Solanaceae - Bignoniaceae - Verbenaceae - Nyctaginaceae - Polygonaceae - Myristicaceae - Lauraceae - Euphorbiaceae - Moraceae - Lacistemaceae- 7 Developmental Aspects- Development of crypts and "cornets" around the stomata - Formation of cork warts - Origin of the oblique position of palisade cells- 8 Ecological Aspects- Xeromorphy, succulence, and hygromorphy- Criteria of xeromorphy - Criteria of hygromorphy- Sun and shade leaf type- Criteria of the sun leaf type - Criteria of the shade leaf type- The significance of the different structural features and their ecological importance- Blade thickness - Number of layers of the upper epidermis - Waxy layers - Cuticle - Thickness of the outer wall of the upper epidermis - Cell size of the upper epidermis, as seen in transection - Cell size and form of the upper and lower epidermis, as seen in surface view - Number of palisade layers - Length of palisade cells - Length/width index of the palisade cells - Index palisade parenchyma/spongy parenchyma - Stomate density - Stomata length - Level of stoma formation - Hair density - Papillas, wall excrescences and surface sculpturing - Density of vascular bundles - Secretory cells - Secretory canals or cavities - Upper and lower hypodermis - Sclereids - Glands - Slimy walls - Stomata in the upper epidermis - Upper epidermis as a water reservoir - Xero-, meso-, hygromorphic leaves and sun and shade leaf type- The progressive transformation of the hygromorphic shade leaf into the xeromorphic sun leaf- Blade size and shape - Blade thickness - Width of outer wall of the upper epidermis - Upper epidermis as a water- storing tissue - Number of epidermis layers - Formation of a (upper or lower) hypodermis - Number of palisade layers - Length of paisade cells - Length/width index of the palisade cells - Chloroplasts - Proportions between palisade and spongy parenchyma - Stomata size and density - Level of stoma formation - Development of "cornets" and crypts - Hair density - Papillas, wall excrescences and surface sculpturing - Density of vascular bundles - Xero-, meso-, hygromorphic leaves - Sun and shade leaf type - The increasing width of the leathery leaf - Comparison of juvenile and adult leaves- Comparison with the cloud forest - The leathery leaf - Environmental conditions- Soil - Water supply - Illumination - Temperature- 9 Taxonomical Aspects- 10 Phylogenetic Aspects- 11 Discussion of the Most Important Results- 12 Figures to the Text- 13 Bibliography- 14 Index of Scientific Plant Names- 15 Index of vernacular plant names- 16 General Index