Accreditation in Hong Kong and international peer review

Increasingly, student outcomes assessment is being viewed as a component of comprehensive academic program review. The Hong Kong peer review process is typical of program review in the United Kingdom and Europe. In the second article in this issue, Ruth Green describes a typical U.S. program review process. —Editor.     

Acquiescence,instructor’s gender bias and validity of student evaluation of teaching

Abstract

The validity of student evaluation of teaching (SET) scores depends on minimum effect of extraneous response processes or biases. A bias may increase or decrease scores and change the relationship with other variables. In contrast, SET literature defines bias as an irrelevant variable correlated with SET scores, and among many, a relevant biasing factor in literature is the instructor’s gender. The study examines the extent to which acquiescence, the tendency to endorse the highest response option across items and bias in the first sense affects students’ responses to a SET rating scale. The study also explores how acquiescence affects the difference in teaching quality (TQ) by instructor’s gender, a bias in the latter sense. SET data collected at a faculty of education in Ontario, Canada were analysed using the Rasch rating scale model. Findings provide empirical support for acquiescence affecting students’ responses. Latent regression analyses show how acquiescence reduces the difference in TQ by instructor’s gender. Findings encourage greater attention to the response process quality as a way to better defend the utility of SET and prevent potentially misleading conclusions from the analysis of SET data.     

Insulator-based dielectrophoresis of mitochondria

Isolated mitochondria display a wide range of sizes plausibly resulting from the coexistence of subpopulations, some of which may be associated with disease or aging. Strategies to separate subpopulations are needed to study the importance of these organelles in cellular functions. Here, insulator-based dielectrophoresis (iDEP) was exploited to provide a new dimension of organelle separation. The dielectrophoretic properties of isolated Fischer 344 (F344) rat semimembranosus muscle mitochondria and C57BL/6 mouse hepatic mitochondria in low conductivity buffer (0.025–0.030 S/m) at physiological pH (7.2–7.4) were studied using polydimethylsiloxane (PDMS) microfluidic devices. First, direct current (DC) and alternating current (AC) of 0–50 kHz with potentials of 0–3000 V applied over a channel length of 1 cm were separately employed to generate inhomogeneous electric fields and establish that mitochondria exhibit negative DEP (nDEP). DEP trapping potential thresholds at 0–50 kHz were also determined to be weakly dependent on applied frequency and were generally above 200 V. Second, we demonstrated a separation scheme using DC potentials <100 V to perform the first size-based iDEP sorting of mitochondria. Samples of isolated mitochondria with heterogeneous sizes (150 nm–2 μm diameters) were successfully separated into sub-micron fractions, indicating the ability to isolate mitochondria into populations based on their size.     

Magnetic compass orientation in C57BL/6J mice

We report evidence for a robust magnetic compass response in C57BL/6J mice. Mice were trained to build their nests in one of four magnetic directions by creating a light gradient along the long axis of a rectangular cage and positioning a nest box at the opposite (dark) end. The mice were then tested overnight in a circular, visually symmetrical arena in one of four magnetic field alignments. The positions of the nests built in the test arena showed strong unimodal orientation in the magnetic direction coinciding with the dark end of the training cage.