Authentic and conventional assessment in Singapore schools : an empirical study of teacher assignments and student work

This is an empirical examination of the quality of teacher assignments and student work in Singapore schools. Using a theoretical framework based on principles of authentic assessment and intellectual quality, two sets of criteria and scoring rubrics were developed for the training of expert teachers to judge the quality of assignments and student work. Following rigorous training, the inter-rater reliability of expert teacher scoring was high. Samples of teacher assignments and student work were collected in English, social studies, mathematics, and science subject areas from a random stratified sample of 30 elementary schools and 29 high schools. For both grade levels, there were significant differences for the authentic intellectual quality of teachers’ assignments by subject area. Likewise, the differences of authentic intellectual quality for student work were significant and varied by subject area. Subject area effect was large. The correlations between the quality of teachers’ assignment tasks and student work were strong and significant at both grade levels. Where teachers set more intellectually demanding tasks, students were more likely to generate work or artefacts judged to be of higher quality. The findings suggest that teacher professional development in authentic intellectual assessment task design can contribute to the improvement of student learning and performance. It is argued that this will be a key requisite of educational systems like Singapore that are seeking to expand pedagogy and student outcomes beyond a focus on factual and rote knowledge.

The evaluation of a biphasic osteochondral implant coupled with an electrospun membrane in a large animal model

Conventional clinical therapies are unable to resolve osteochondral defects adequately, hence tissue engineering solutions are sought to address the challenge. A biphasic implant which was seeded with Mesenchymal Stem Cells (MSC) and coupled with an electrospun membrane was evaluated as an alternative. This dual phase construct comprised of a Polycaprolactone (PCL) cartilage scaffold and a Polycaprolactone - Tri Calcium Phosphate (PCL - TCP) osseous matrix. Autologous MSC was seeded into the entire implant via fibrin and the construct was inserted into critically sized osteochondral defects located at the medial condyle and patellar groove of pigs. The defect was resurfaced with a PCL - collagen electrospun mesh that served as a substitute for periosteal flap in preventing cell leakage. Controls either without implanted MSC or resurfacing membrane were included. After 6 months, cartilaginous repair was observed with a low occurrence of fibrocartilage at the medial condyle. Osteochondral repair was promoted and host cartilage degeneration was arrested as shown by the superior Glycosaminoglycan (GAG) maintenance. This positive morphological outcome was supported by a higher relative Young's modulus which indicated functional cartilage restoration. Bone in growth and remodeling occurred in all groups with a higher degree of mineralization in the experimental group. Tissue repair was compromised in the absence of the implanted cells or the resurfacing membrane. Moreover healing was inferior at the patellar groove as compared to the medial condyle and this was attributed to the native biomechanical features.

Influence of spherical intraocular lens implantation and conventional laser in situ keratomileusis on peripheral ocular aberrations

Aim: To measure the influence of spherical intraocular lens implantation and conventional myopic laser in situ keratomileusis on peripheral ocular aberrations. Setting: Visual & Ophthalmic Optics Laboratory, School of Optometry & Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia. Methods: Peripheral aberrations were measured using a modified commercial Hartmann-Shack aberrometer across 42° x 32° of the central visual field in 6 subjects after spherical intraocular lens (IOL) implantation and in 6 subjects after conventional laser in situ keratomileusis (LASIK) for myopia. The results were compared with those of age matched emmetropic and myopic control groups. Results: The IOL group showed a greater rate of quadratic change of spherical equivalent refraction across the visual field, higher spherical aberration, and greater rates of change of higher-order root-mean-square aberrations and total root-mean-square aberrations across the visual field than its emmetropic control group. However, coma trends were similar for the two groups. The LASIK group had a greater rate of quadratic change of spherical equivalent refraction across the visual field, higher spherical aberration, the opposite trend in coma across the field, and greater higher-order root-mean-square aberrations and total root-mean-square aberrations than its myopic control group. Conclusion: Spherical IOL implantation and conventional myopia LASIK increase ocular peripheral aberrations. They cause considerable increase in spherical aberration across the visual field. LASIK reverses the sign of the rate of change in coma across the field relative to that of the other groups. Keywords: refractive surgery, LASIK, IOL implantation, aberrations, peripheral aberrations

Zinc supplementation at conventional doses does not improve the disturbance of taste perception in hemodialysis patients

Objective: To determine the effect of zinc supplementation on taste perception in a group of hemodialysis patients. Design and Setting: Double-blind randomized placebo-controlled study in a teaching hospital dialysis unit. Patients: Fifteen stable hemodialysis patients randomized to placebo (6 male, 2 female; median age, 67; range, 30 to 72 years) or treatment (5 male, 2 female; median age, 60; range, 31 to 76 years). Intervention: Treatment group received zinc sulfate 220 mg per day for 6 weeks, and the placebo group received an apparently identical dummy pill. Main Outcome Measures: Taste scores by visual analogue scales, normalized protein catabolic rate and plasma, whole blood and red cell zinc levels. Results: At baseline, sweet and salt tastes were identified correctly by both groups. Sour was often confused with salt. Sour solutions of different concentrations were not distinguishable. Taste scores were not different after 6 weeks for either group. There was no significant increment in zinc levels or normalized protein catabolic rate for either group. Conclusion: We found a disturbance of taste perception in hemodialysis patients, particularly for the sour modality, which was not corrected by this regimen of zinc supplementation. These results cast doubts on the conclusions of earlier studies that indicated an improvement in taste after zinc supplementation.

A comparative study of interactive rockclimbing guidebooks and conventional hardcopy guidebooks

Climbing guidebooks have been in existence ever since people started climbing cliffs for recreation. It has only been recently that these guidebooks have started to include photographs to help identification of climbs. To date, there are very few interactive guidebooks that are available online which include the ability to filter climbs and climbing areas based upon specific characteristics. Being able to interrogate a database of climbs and climbing areas by grade, style of climbing, quality of climbing,and length of climbs would be a significant addition to the guidebooks that are currently available. Integrating a fully illustrated database of climbs with open source mapping software such as Google Maps would extend the utility of current guidebooks significantly. As portable devices become more commonplace, the ability to further combine these guidebooks with GPS technology would make the location and identification of climbs much simpler. This study compares conventional hardcopy guidebooks with several online guidebooks. In addition, several Decision Support Systems are analysed to assess the ways in which Geographic Information Systems are integrated to assist in decision making. A prototype interactive guidebook was developed after presenting a survey to a group of climbers to assess what they would find useful in an online resource. This survey found that most climbers would like to see climbs represented on a map of the climbing site in order to aid in locating them. They also suggested that being able to filter climbs by various criteria would be useful. These features were subsequently integrated into the prototype. After review by several climbers it was found that this system has many benefits over conventional hardcopy guidebooks; however, it was also noted that to be even more useful further work needed to be done to improve the functionality of the prototypes. This work would include an ability to print a selection of climbs from those ranges searched.

Evidence of disagreement between patient-perceived change and conventional longitudinal evaluation of change in health-related quality of life among older adults

Objective: To identify agreement levels between conventional longitudinal evaluation of change (post–pre) and patient-perceived change (post–then test) in health-related quality of life. Design: A prospective cohort investigation with two assessment points (baseline and six-month follow-up) was implemented. Setting: Community rehabilitation setting. Subjects: Frail older adults accessing community-based rehabilitation services. Intervention: Nil as part of this investigation. Main measures: Conventional longitudinal change in health-related quality of life was considered the difference between standard EQ-5D assessments completed at baseline and follow-up. To evaluate patient-perceived change a ‘then test’ was also completed at the follow-up assessment. This required participants to report (from their current perspective) how they believe their health-related quality of life was at baseline (using the EQ-5D). Patient-perceived change was considered the difference between ‘then test’ and standard follow-up EQ-5D assessments. Results: The mean (SD) age of participants was 78.8 (7.3). Of the 70 participants 62 (89%) of data sets were complete and included in analysis. Agreement between conventional (post–pre) and patient-perceived (post–then test) change was low to moderate (EQ-5D utility intraclass correlation coefficient (ICC)¼0.41, EQ-5D visual analogue scale (VAS) ICC¼0.21). Neither approach inferred greater change than the other (utility P¼0.925, VAS P¼0.506). Mean (95% confidence interval (CI)) conventional change in EQ-5D utility and VAS were 0.140 (0.045,0.236) and 8.8 (3.3,14.3) respectively, while patient-perceived change was 0.147 (0.055,0.238) and 6.4 (1.7,11.1) respectively. Conclusions: Substantial disagreement exists between conventional longitudinal evaluation of change in health-related quality of life and patient-perceived change in health-related quality of life (as measured using a then test) within individuals.

Test and evaluation of non conventional instrument transformers and sampled value process bus on Powerlink's transmission network

IEC 61850 Process Bus technology has the potential to improve cost, performance and reliability of substation design. Substantial costs associated with copper wiring (designing, documentation, construction, commissioning and troubleshooting) can be reduced with the application of digital Process Bus technology, especially those based upon international standards. An IEC 61850-9-2 based sampled value Process Bus is an enabling technology for the application of Non-Conventional Instrument Transformers (NCIT). Retaining the output of the NCIT in its native digital form, rather than conversion to an analogue output, allows for improved transient performance, dynamic range, safety, reliability and reduced cost. In this paper we report on a pilot installation using NCITs communicating across a switched Ethernet network using the UCAIug Implementation Guideline for IEC 61850-9-2 (9-2 Light Edition or 9-2LE). This system was commissioned in a 275 kV Line Reactor bay at Powerlink Queensland’s Braemar substation in 2009, with sampled value protection IEDs 'shadowing' the existing protection system. The results of commissioning tests and twelve months of service experience using a Fibre Optic Current Transformer (FOCT) from Smart Digital Optics (SDO) are presented, including the response of the system to fault conditions. A number of remaining issues to be resolved to enable wide-scale deployment of NCITs and IEC 61850-9-2 Process Bus technology are also discussed.

Short-term retention of labeled chondrocyte subpopulations in stratified tissue-engineered cartilaginous constructs implanted in vivo in mini-pigs

It is likely that effective application of cell-laden implants for cartilage defects depends on retention of implanted cells and interaction between implanted and host cells. The objectives of this study were to characterize stratified cartilaginous constructs seeded sequentially with superficial (S) and middle (M) chondrocyte subpopulations labelled with fluorescent cell tracking dye PKH26 (*) and determine the degree to which these stratified cartilaginous constructs maintain their architecture in vivo after implantation in mini-pigs for 1 week. Alginate-recovered cells were seeded sequentially to form stratified S*/M (only S cells labelled) and S*/M* (both S and M cells labelled) constructs. Full-thickness defects (4 mm diameter) were created in the patellofemoral groove of adult Yucatan mini-pigs and filled with portions of constructs or left empty. Constructs were characterized biochemically, histologically, and biomechanically, and stratification visualized and quantified, before and after implant. After 1 week, animals were sacrificed and implants retrieved. After 1 week in vivo, glycosaminoglycan and collagen content of constructs remained similar to that at implant, whereas DNA content increased. Histological analyses revealed features of an early repair response, with defects filled with tissues containing little matrix and abundant cells. Some implanted (PKH26-labeled) cells persisted in the defects, although constructs did not maintain a stratified organization. Of the labelled cells, 126 +/- 38% and 32 +/- 8% in S*/M and S*/M* constructs, respectively, were recovered. Distribution of labelled cells indicated interactions between implanted and host cells. Longer-term in vivo studies will be useful in determining whether implanted cells are sufficient to have a positive effect in repair.

The three little pigs and the art of playfulness

A number of pictorial based texts for children use animals as models for displaying or approaching aspects of childhood. Although authors and illustrators utilise various tactics for including anthropomorphic animals in their books, those that are used as 'surrogate' children can be seen to focus in the main on issues of behaviour, socialisation and maturity - issues that reflect the everyday life of the growing child. This paper aims to explore three pictorial texts that specifically utilise the pig character as a child model, to facilitate for authors/illustrators the opportunity to deal with examples of childhood experience. The paper also tentatively examines how such roles might encourage a reassessment of other more stereotypical associations some audiences have historically/culturally formed about the pig.