Web-based formative assessment through clinical cases: role in pathophysiology teaching

Background Active learning strategies such as formative assessment through clinical cases may help to get a deeper learning. We have studied the effect of this kind of online formative assessment in pathophysiology teaching. Methods Seven brief clinical cases were used to give formative assessment in the first semester of a pathophysiology course. To evaluate its effect on learning, we analyzed the proportion of students that passed the end of semester exam with a score above 60 over 100. We also analyzed the effect of the intervention according to the students’ previous academic performance. Results Ninety-six students participated in the study and sat the exam. Sixty-five of them passed it. Students that passed the exam had a higher previous academic performance and had done a higher number of exercises of formative assessment, both in univariate and multivariate analysis. The participants were divided in three groups, according to their previous academic performance. In the intermediate group, the number of cases done by the students who passed the exam was significantly higher than in those who did not pass it (median: 4 versus 0; P = 0.009). Conclusion Formative assessment through web-based clinical cases was followed by an improvement of the academic results in pathophysiology, mainly in students with intermediate performance.

XYZ Micropositioning System Based on Compliance Mechanisms Fabricated by Additive Manufacturing

This article presents the design and implementation of a micropositioning system actuated by three piezoelectric stacks to control its displacements on XYZ axes. The use of conventional piezoelectric buzzers allows us to reduce fabrication costs. The working or mobile platform is the base for objects that will be manipulated, for example, in automated assembling. The micropositioner can be integrated into a microgripper to generate a complete manipulation system. For micropositioner fabrication, at first, Polylactic Acid (PLA) was chosen as the structural material, but after simulation and some experimental tests performed with a micropositioner made of Acrylonitrile Butadiene Styrene (ABS), it showed larger displacement (approx. 20%) due to its lower stiffness. A third test was performed with a positioner made with Polyethylene Terephthalate Glycol (PETG), obtaining an intermediate performance. The originality of this work resides in the geometrical arrangement based on thermoplastic polymer compliance mechanisms, as well as in the use of additive manufacturing to fabricate it. An experimental setup was developed to carry out experimental tests. ANSYS™ was used for simulation.

Comparison of staircase and asymmetrical before-after control impact (aBACI) experimental designs to test the effectiveness of stream restoration at increasing juvenile steelhead density

Before-after-control-impact (BACI) experimental designs are commonly used in large-scale environmental experiments but these designs can be confounded by location and time interactions. Staircase designs, where replicate treatments are staggered temporally, have been suggested as an alternative to BACI designs. We performed a simulation study based on data from an ongoing watershed-scale restoration experiment within three streams to test the effectiveness of adding large wood to increase habitat complexity and abundance and productivity of juvenile steelhead (Oncorhynchus mykiss). We compared the power of two asymmetric BACI (aBACI) designs to two staircase designs for detecting changes in the density of steelhead (fish/m2). A staircase design where treatments were temporally staggered in one treatment section in each stream had the highest power and best precision, especially when the innate spatial and temporal variances of steelhead density were large. A traditional BACI performed the worst, and a variation on another BACI and staircase design had intermediate performance. Multi-stream staircase designs are also more logistically and economically feasible and can maximize learning by replicating experiments across different stream types.

Web-based Formative Assessment Through Clinical Cases: Role in Pathophysiology Teaching.

Background. Active learning strategies such as formative assessment through clinical cases may help to get a deeper learning. We have studied the effect of this kind of online formative assessment in pathophysiology teaching. Methods. Seven brief clinical cases were used to give formative assessment in the first semester of a pathophysiology course. To evaluate its effect on learning, we analyzed the proportion of students that passed the end of semester exam with a score above 60 over 100. We also analyzed the effect of the intervention according to the students’ previous academic performance. Results. Ninety-six students participated in the study and sat the exam. Sixty-five of them passed it. Students that passed the exam had a higher previous academic performance and had done a higher number of exercises of formative assessment, both in univariate and multivariate analysis. The participants were divided in three groups, according to their previous academic performance. In the intermediate group, the number of cases done by the students who passed the exam was significantly higher than in those who did not pass it (median: 4 versus 0; P=0.009). Conclusion. Formative assessment through web-based clinical cases increases knowledge acquisitions in pathophysiology, mainly in students with intermediate performance.

Patterns of Prefrontal Activation and Performance During Walking Tasks Among Older Adults

Differences in prefrontal cortex (PFC) control of walking in older age likely arise from changes in neural capacity and compensation. PFC activation by changes in oxygenated hemoglobin from functional near infra-red spectroscopy was examined in 29 older adults (mean age=76). Tasks included standing with cognitive challenge and walking with and without cognitive challenge on even and uneven surfaces. Three PFC activation-performance patterns were identified using K-means clustering: 1) low activation during walking tasks and high activation during standing cognitive task, with the best performance in terms of walking speed and cognitive performance (n=10); 2) low activation on all tasks, with the lowest performance (n=15); 3) high activation during walking and low activation during cognitive, with intermediate performance (n=5). Associations of patterns with cognitive function and structural neuroimaging were explored, with results informing interpretation of functional changes of PFC during aging process, including compensatory mechanisms for primary network impairment.

Functional Tradeoffs Carry Phenotypes Across the Valley of the Shadow of Death

Synopsis Functional tradeoffs are often viewed as constraints on phenotypic evolution, but they can also facilitate evolution across the suboptimal valleys separating performance peaks. I explore this process by reviewing a previously published model of how disruptive selection from competing functional demands defines an intermediate performance optimum for morphological systems that cannot simultaneously be optimized for all of the functional roles they must play. Because of the inherent tradeoffs in such a system, its optimal morphology in any particular environmental context will usually be intermediate between the performance peaks of the competing functions. The proportional contribution of each functional demand can be estimated by maximum likelihood from empirically observed morphologies, including complex ones measured with multivariate geometric morphometrics, using this model. The resulting tradeoff weight can be mapped onto a phylogenetic tree to study how the performance optimum has shifted across a functional landscape circumscribed by the function-specific performance peaks. This model of tradeoff evolution is sharply different from one in which a multipeak Ornstein–Uhlenbeck (OU) model is applied to a set of morphologies and a phylogenetic tree to estimate how many separate performance optima exist. The multi-peak OU approach assumes that each branch is pushed toward one of two or more performance peaks that exist simultaneously and are separated by valleys of poor performance, whereas the model discussed here assumes that each branch tracks a single optimal performance peak that wanders through morphospace as the balance of functional demands shifts. That the movements of this net performance peak emerge from changing frequencies of selection events from opposing functional demands are illustrated using a series of computational simulations. These simulations show how functional tradeoffs can carry evolution across putative performance valleys: even though intermediate morphologies may not perform optimally for any one function, they may represent the optimal solution in any environment in which an organism experiences competing functional demands.