Resource‐based learning strategies: Implications for students and institutions

This paper reports some findings from a project in implementing resource‐based learning in economics, and identifies some implications for students and institutions. These include student responses to a mid‐semester evaluation and the views of the project team. The latter have been informed by action research which sought to recognize students’ individual differences, employ active learning methods and, above all, integrate IT into the curriculum. While innovative strategies are clearly welcomed, students show strong attachment to some traditional methods. Most of those who suggested changes to the range of activities asked for reinstatement of at least some lectures, generally as additions to existing activities. Implications include the need for students and staff to acquire a wide range of new skills, for large‐scale curriculum review if new learning technologies are to be fully integrated, and the need to acknowledge that, given student and staff perceptions of change, the process may be long and costly

RAPID: A Unique Cruise Opportunity to Test the Effect of Trace Metal Limitation on Oxidative Stress and Coral Bleaching

Intellectual Merit. Coral bleaching has increased dramatically in frequency, severity, and geographic extent since the 1980\u27s and this trend is anticipated to continue, causing major environmental and economic impacts in tropical regions. This bleaching, or loss by corals of their photosynthetic endosymbiotic dinoflagellates (zooxanthellae; Symbiodinium spp.), appears to result from increased oxidative stress arising from the combined effects of elevated temperature at high light intensities. However, the mechanisms underlying this failure are not understood. The premise of the PIs\u27 current project entitled Effects of Trace Metal Limitation on Oxidative Stress in Zooxanthellae and Its Role in Coral Bleaching (OCE - 0648478) is that the necessary up-regulation of zooxanthellae antioxidant defenses is restricted by low concentrations of dissolved Fe, Zn and Cu; metals essential for antioxidant enzyme function (Cu, Zn-, Mn-, and Fe-SOD; catalase [Fe]; ascorbate peroxidase [Fe]). Findings from their laboratory and field manipulation experiments show that restricting Fe, and Cu/Zn availability to coral hosts under high (but not low) temperature and light intensity indeed can significantly decrease both photosynthetic efficiency of symbionts in-hospite and ROS enzyme activities, while increasing non-photosynthetic quenching of their photosystems; each indicators of the onset of bleaching conditions. However, although there is high integrity within each experiment, they have found this pattern is not consistent with all coral colonies. Based on limited sampling, it appears that corals collected from the outer shelf region normally (but not always) display indications of oxidative stress under conditions of decreased metal availability, while those collected nearshore, or maintained in coastally-derived flowing seawater (where dissolved metal concentrations are higher), often show little discernable effect. Excess metal uptake and storage is well described in the marine phytoplankton literature, which suggests that the history of the coral metal exposure is a critical factor, both with respect to our experiments as well as to the distribution of coral bleaching observed. The PIs have an unique and unforeseen opportunity to test this hypothesis by joining an Australian Institute for Marine Sciences research cruise to Flinders Reef; an offshore atoll in the Coral Sea that is substantially more distant from sporadic terrestrial metal inputs that our previous study sites. They will participate in this cruise to run on-deck incubations testing the effect of reduced and marginally elevated Fe, Cu, Zn and Mn concentrations on coral photosynthetic efficiency, ROS enzyme activities, symbiont pigment composition, and ROS enzyme and other gene expression. This geographical site will provide the ideal test site for verifying their findings of metal effects on oxidative stress in zooxanthellae, and identify some of the key mechanisms and nutritional factors contributing to the increasingly frequent and severe coral bleaching events in tropical waters.Broader Impacts: This project will provide a unique research opportunity for two graduate students and a junior female Ph.D. scientist, who will use aspects of the work for their thesis and career development. The research addresses the fundamental unknowns of the controls of coral bleaching, one of the leading threats to marine biodiversity and economic stability of tropical nations. The findings will provide a key test of laboratory- and field-developed hypotheses of the role of trace metal limitation as a contributor to oxidative stress of zooxanthellae and their coral hosts; a precursor to coral bleaching. A modular series of lectures and demonstrations targeting both upper K-12 and undergraduates will be developed and will be incorporated into existing outreach programs and undergraduate courses in Marine Science at the University of Maine. The phototrophic symbiosis between zooxanthellae and corals, and its disruption by physical environmental factors, provides an inherently powerful case study for the integration of chemistry, physics, and biology that will illustrate to marine science undergraduates the need for rigorous training in the quantitative physical sciences. The findings will provide key insights to the factors that influence the severity of bleaching events, and possibly suggest realistic mitigation strategies to minimize bleaching events in localized environmentally or economically sensitive regions

How Do Communities Use a Participatory Public Health Approach to Build Resilience? The Los Angeles County Community Disaster Resilience Project.

Community resilience is a key concept in the National Health Security Strategy that emphasizes development of multi-sector partnerships and equity through community engagement. Here, we describe the advancement of CR principles through community participatory methods in the Los Angeles County Community Disaster Resilience (LACCDR) initiative. LACCDR, an initiative led by the Los Angeles County Department of Public Health with academic partners, randomized 16 community coalitions to implement either an Enhanced Standard Preparedness or Community Resilience approach over 24 months. Facilitated by a public health nurse or community educator, coalitions comprised government agencies, community-focused organizations and community members. We used thematic analysis of data from focus groups (n = 5) and interviews (n = 6 coalition members; n = 16 facilitators) to compare coalitions' strategies for operationalizing community resilience levers of change (engagement, partnership, self-sufficiency, education). We find that strategies that included bidirectional learning helped coalitions understand and adopt resilience principles. Strategies that operationalized community resilience levers in mutually reinforcing ways (e.g., disseminating information while strengthening partnerships) also secured commitment to resilience principles. We review additional challenges and successes in achieving cross-sector collaboration and engaging at-risk groups in the resilience versus preparedness coalitions. The LACCDR example can inform strategies for uptake and implementation of community resilience and uptake of the resilience concept and methods

Effects of Trace Metal Limitation on Oxidative Stress in Zooxanthellae and Its Role in Coral Bleaching

Coral bleaching has increased dramatically in frequency, severity, and geographic extent since the 1980s and this trend is anticipated to continue, causing major environmental and economic impacts in tropical regions. This bleaching - the loss by corals of their photosynthetic endosymbiotic dinoflagellates (zooxanthellae; Symbiodinium spp.) - involves increased oxidative stress arising from the combined effects of elevated temperature at high light intensities. Although the production of reactive oxygen species (ROS) in corals and phytoplankton is routine during daylight hours, the failure of antioxidant defenses in zooxanthellae becomes catastrophic under comparatively small changes in environmental temperature, because reef corals live close to their upper thermal limits. The mechanisms underlying this failure are not understood, but fall into two categories: (1) the temperature/irradiance conditions lie beyond the capacity for thermal acclimatization by corals and their endo-symbionts, or (2) the necessary enhancement of antioxidant defenses in zooxanthellae is hindered by nutrient deficiencies. In this project, the working hypothesis is that low ambient concentrations of dissolved iron, zinc, copper and perhaps manganese (Fe, Zn, Cu, and Mn) in oligotrophic tropical surface waters, combined with regulation of metal supply to zooxanthellae by the coral host, restrict the compensatory elevation of metal-dependent antioxidant enzymes with rising ROS production, and this resource limitation contributes to coral bleaching. This hypothesis will be investigated in three stages: with pure clonal cultures of zooxanthella isolates; in coral colony culture experiments; and in samples on areas of the Great Barrier Reef, Australia, observed to be susceptible or resistant to coral bleaching. The primary goals of the pure culture experiments are to 1) identify which of the known metals involved in antioxidant enzymes (Fe, Cu, Zn, Mn) are important in zooxanthellae, 2) determine the thresholds of metal nutrition (both in supply and intracellular metal quotas) below which onset of uncontrolled oxidative stress occurs in the zooxanthellae, and 3) ascertain whether these relationships differ significantly among bleaching sensitive and insensitive Symbiodinium species. In addition to verifying the findings in coral/algal symbioses, coral experiments will be used to determine whether the timing and magnitude of bleaching indicators change with metal nutrition, and whether bleaching-sensitive corals can become more resistant by increasing their metal quotas. The linkage between trace metals and antioxidant enzymes is well established in other biological systems but has not been examined in coral/zooxanthellar associations. The proposed work brings together experts in trace metal/ phytoplankton interactions, phytoplankton photo-physiology and oxidative stress, photo-oxidative defenses in reef corals, and molecular biology of marine symbioses to provide mechanistic understanding of coral bleaching, increasing predictive insights to the global trend of coral bleaching. This project will support the education and research training of two Ph.D. students who would test hypotheses integral to the work as parts of their dissertations. Two postdoctoral scientists will participate in the planning, management, and research of the project, providing opportunities to refine their professional development and their mentoring skills necessary for career success. Public lectures on corals and global climate change are planned. The findings will provide insights to the factors influencing the severity of bleaching events, and may suggest realistic mitigation strategies to minimize bleaching in localized environmentally or economically sensitive regions

On the evaluation of methods for the recovery of plant root systems from X-ray computed tomography images

X-ray micro computed tomography (µCT) allows non-destructive visualisation of plant root systems within their soil environment and thus offers an alternative to commonly used destructive methodologies for the examination of plant roots and their interaction with the surrounding soil. Various methods for the recovery of root system information from X-ray CT image data have been presented in the literature. Detailed, ideally quantitative, evaluation is essential, in order to determine the accuracy and limitations of the proposed methods, and to allow potential users to make informed choices between them. This, however, is a complicated task. Three-dimensional ground truth data is expensive to produce, and the complexity of X-ray CT data means that manually generated ground truth may not be definitive. Similarly, artificially generated data is not entirely representative of real samples. The aims of this work are to raise awareness of the evaluation problem and to propose experimental approaches that allow the performance of root extraction methods to be assessed, ultimately improving the techniques available. To illustrate the issues, tests are conducted using both artificially generated images and real data samples

Auxin fluxes through plasmodesmata modify root-tip auxin distribution

© 2020. Published by The Company of Biologists Ltd. Auxin is a key signal regulating plant growth and development. It is well established that auxin dynamics depend on the spatial distribution of efflux and influx carriers on the cell membranes. In this study, we employ a systems approach to characterise an alternative symplastic pathway for auxin mobilisation via plasmodesmata, which function as intercellular pores linking the cytoplasm of adjacent cells. To investigate the role of plasmodesmata in auxin patterning, we developed a multicellular model of the Arabidopsis root tip. We tested the model predictions using the DII-VENUS auxin response reporter, comparing the predicted and observed DII-VENUS distributions using genetic and chemical perturbations designed to affect both carrier-mediated and plasmodesmatal auxin fluxes. The model revealed that carrier-mediated transport alone cannot explain the experimentally determined auxin distribution in the root tip. In contrast, a composite model that incorporates both carrier-mediated and plasmodesmatal auxin fluxes re-capitulates the root-tip auxin distribution. We found that auxin fluxes through plasmodesmata enable auxin reflux and increase total root-tip auxin. We conclude that auxin fluxes through plasmodesmata modify the auxin distribution created by efflux and influx carriers

Adding a piece to the leaf epidermal cell shape puzzle

The jigsaw puzzle-shaped pavement cells in the leaf epidermis collectively function as a load-bearing tissue that controls organ growth. In this issue of Developmental Cell, Majda et al. (2017) shed light on how the jigsaw shape can arise from localized variations in wall stiffness between adjacent epidermal cells

Positioning the Root Elongation Zone Is Saltatory and Receives Input from the Shoot

In the root, meristem and elongation zone lengths remain stable, despite growth and division of cells. To gain insight into zone stability, we imaged individual Arabidopsis thaliana roots through a horizontal microscope, and used image analysis to obtain velocity profiles. For a root, velocity profiles obtained every 5 min over 3 h coincided closely, implying that zonation is regulated tightly. However, the position of the elongation zone saltated, by on average 17 μm every 5 min. Saltation was apparently driven by material elements growing faster and then slower, while moving through the growth zone. When the shoot was excised, after about 90 minutes, growth zone dynamics resembled those of intact roots, except that the position of the elongation zone moved, on average, rootward, by several hundred microns in 24 h. We hypothesize that mechanisms determining elongation zone position receive input from the shoot

A Cross-Sectional Study of the Association between Overnight Call and Irritable Bowel Syndrome in Medical Students

BACKGROUND: Shift work has been associated with irritable bowel syndrome (IBS), which includes gastrointestinal symptoms such as abdominal pain, constipation and diarrhea. Overnight call shifts also lead to a disruption of the endogenous circadian rhythm. HYPOTHESIS: Medical students who perform intermittent overnight call shifts will demonstrate a higher prevalence of IBS symptoms when compared with medical students who perform no overnight call shifts. METHODS: First- and second-year (preclinical) medical students have no overnight call requirements, whereas third- and fourth-year medical (clerkship) students do have overnight call requirements. All medical students at the Schulich School of Medicine and Dentistry (London, Ontario) were invited to complete an anonymous, web-based survey or an identical paper copy that included demographic data, the Rome III questionnaire and the IBS-Quality of Life measure (IBS-QOL). The prevalence of IBS symptoms and quality of life secondary to those symptoms were determined. RESULTS: Data were available for 247 medical students (110 pre-clinical students, 118 clerkship students and 19 excluded surveys). There was no significant difference in the presence of IBS between preclinical and clerkship students (21 of 110 [19.1%] versus 26 of 118 [22.0%]; P=0.58). The were no significant differences in mean (± SD) IBS-QOL score of those with IBS between preclinical (43.5±8.3) and clerkship students (45.7±13.8) (P=0.53). CONCLUSIONS: Participation in overnight call was not associated with the development of IBS or a lower quality of life secondary to IBS in medical students