The Journal of the Center for Interdisciplinary Teaching and Learning

IMPACT: The Journal of the Center for Interdisciplinary Teaching & Learning is a peer-reviewed, biannual online journal that publishes scholarly and creative non-fiction essays about the theory, practice and assessment of interdisciplinary education. Impact is produced by the Center for Interdisciplinary Teaching & Learning at the College of General Studies, Boston University (www.bu.edu/cgs/citl).In this issue, podcasts are looked at as a pedagogical game changer. Using the award-wining podcast Serial as their catalyst, this issue's essayists look at podcast's emerging role in higher education, how multimodal learning can help students find their voices, the podcast's place in the curriculum at a criminal justice college, and how podcasts can inspire students to reflectively assess their own writing. Our reviewers take a critical look at the podcasts Welcome to Night Vale and Revisionist History

From Food to Offspring Down: Tissue-Specific Discrimination and Turn-Over of Stable Isotopes in Herbivorous Waterbirds and Other Avian Foraging Guilds

Isotopic discrimination and turn-over are fundamental to the application of stable isotope ecology in animals. However, detailed information for specific tissues and species are widely lacking, notably for herbivorous species. We provide details on tissue-specific carbon and nitrogen discrimination and turn-over times from food to blood, feathers, claws, egg tissues and offspring down feathers in four species of herbivorous waterbirds. Source-to-tissue discrimination factors for carbon (δ13C) and nitrogen stable isotope ratios (δ15N) showed little variation across species but varied between tissues. Apparent discrimination factors ranged between −0.5 to 2.5‰ for δ13C and 2.8 to 5.2‰ for δ15N, and were more similar between blood components than between keratinous tissues or egg tissue. Comparing these results with published data from other species we found no effect of foraging guild on discrimination factors for carbon but a significant foraging-guild effect for nitrogen discrimination factors

Blunted Neuronal Calcium Response to Hypoxia in Naked Mole-Rat Hippocampus

Naked mole-rats are highly social and strictly subterranean rodents that live in large communal colonies in sealed and chronically oxygen-depleted burrows. Brain slices from naked mole-rats show extreme tolerance to hypoxia compared to slices from other mammals, as indicated by maintenance of synaptic transmission under more hypoxic conditions and three fold longer latency to anoxic depolarization. A key factor in determining whether or not the cellular response to hypoxia is reversible or leads to cell death may be the elevation of intracellular calcium concentration. In the present study, we used fluorescent imaging techniques to measure relative intracellular calcium changes in CA1 pyramidal cells of hippocampal slices during hypoxia. We found that calcium accumulation during hypoxia was significantly and substantially attenuated in slices from naked mole-rats compared to slices from laboratory mice. This was the case for both neonatal (postnatal day 6) and older (postnatal day 20) age groups. Furthermore, while both species demonstrated more calcium accumulation at older ages, the older naked mole-rats showed a smaller calcium accumulation response than even the younger mice. A blunted intracellular calcium response to hypoxia may contribute to the extreme hypoxia tolerance of naked mole-rat neurons. The results are discussed in terms of a general hypothesis that a very prolonged or arrested developmental process may allow adult naked mole-rat brain to retain the hypoxia tolerance normally only seen in neonatal mammals

Fructose-driven glycolysis supports anoxia resistance in the naked mole-rat

The African naked mole-rat’s ($\textit{Heterocephalus glaber}$) social and subterranean lifestyle generates a hypoxic niche. Under experimental conditions, naked mole-rats tolerate hours of extreme hypoxia and survive 18 minutes of total oxygen deprivation (anoxia) without apparent injury. During anoxia, the naked mole-rat switches to anaerobic metabolism fueled by fructose, which is actively accumulated and metabolized to lactate in the brain. Global expression of the GLUT5 fructose transporter and high levels of ketohexokinase were identified as molecular signatures of fructose metabolism. Fructose-driven glycolytic respiration in naked mole-rat tissues avoids feedback inhibition of glycolysis via phosphofructokinase, supporting viability. The metabolic rewiring of glycolysis can circumvent the normally lethal effects of oxygen deprivation, a mechanism that could be harnessed to minimize hypoxic damage in human disease.Work was supported aEuropean Research Council (294678), the Deutsche Forschungsgemeinschaft SFB 665 and Go865/9-1, NSF (grant #0744979 ), NIH (grants HL71626 and HL606

Geobiology of a lower Cambrian carbonate platform, Pedroche Formation, Ossa Morena Zone, Spain

The Cambrian Pedroche Formation comprises a mixed siliciclastic-carbonate succession recording subtidal deposition on a marine platform. Carbonate carbon isotope chemostratigraphy confirms previous biostratigraphic assignment of the Pedroche Formation to the Atdabanian regional stage of Siberia, correlative to Cambrian Series 2. At the outcrop scale, thrombolitic facies comprise ~. 60% of carbonate-normalized stratigraphy and coated-grains another ~. 10%. Petrographic point counts reveal that skeletons contribute at most 20% to thrombolitic inter-reef and reef-flank lithologies; on average, archaeocyath clasts make up 68% of skeletal materials. In contrast, petrographic point counts show that skeletons comprise a negligible volume of biohermal and biostromal thrombolite, associated nodular carbonate facies, and ooid, oncoid and peloid grainstone facies. As such, archaeocyathan reefal bioconstructions represent a specific and limited locus of skeletal carbonate production and deposition. Consistent with data from coeval, globally dispersed lower Cambrian successions, our analysis of the Pedroche Formation supports the view that lower Cambrian carbonates have more in common with earlier, Neoproterozoic deposits than with younger carbonates dominated by skeletal production and accumulation. © 2013 Elsevier B.V.Jessica R. Creveling, David Fernández-Remolar, Marta Rodríguez-Martínez, Silvia Menéndez, Kristin D. Bergmann, Benjamin C. Gill, John Abelson, Ricardo Amils, Bethany L. Ehlmann, Diego C. García-Bellido, John P. Grotzinger, Christian Hallmann, Kathryn M. Stack, Andrew H. Knol

Extreme Resistance to Oxygen Deprivation in Brain Tissue from the Naked Mole-Rat

The naked mole-rat lives in large colonies living completely underground, a very unique way of life. This leads to an environment where the air is low in oxygen and high in carbon dioxide. Adaptations in blood and metabolism have been previously reported in the naked mole-rat that help it survive these conditions. My study is aimed at specifically examining the tolerance to low oxygen (hypoxia) in the brain of this unusual species. My working hypothesis was that naked mole-rats retain neonatal protective characteristics against hypoxia into adulthood. First we exposed whole animals to no oxygen (anoxia) to see how long they survived. A group of naked mole-rats was exposed for around 6 minutes and still recovered once put back in room air. This is remarkable when compared to mice, which only survived around 45 seconds and did not recover. We then measured the levels of ATP in the brains of adult naked mole-rats compared to adult mice and neonatal mice. This is important because ATP is the energy of the brain and oxygen is needed for its synthesis. We found that ATP stores in adult naked mole-rat brain depleted slower than in adult mouse brain, however, it was not as slow as in neonatal mouse brain. Next, since many hypoxia-tolerant model systems are able to prevent an increase in internal calcium that leads to cell death during hypoxia, we wanted to establish if naked mole-rats could prevent this as well. We determined that in hippocampal brain slices from naked mole-rats the increase in internal calcium was significantly reduced compared to both neonatal and weanling mice. Lastly, we wanted to find out if the adult naked mole-rat brain retained more of the NMDA receptor subunit NR2D into adulthood compared to adult mouse brain. This subtype closes during hypoxia and is usually expressed more in neonatal mammals than in adults. We revealed that adult naked mole-rats do have a higher proportion of the NR2D subunit in adulthood compared to mice. These finding lead us to conclude that naked mole-rats are retaining neonatal protective characteristics against hypoxia

Fitness Measures Among Boy Scouts Completing the Personal Fitness Merit Badge

Introduction: A formative framework for positive lifestyle and health behaviors is established during adolescence. The Boy Scouts of America (BSA) is one organization that promotes healthy lifestyles among adolescent males and includes earning the Personal Fitness Merit Badge (PFMB). Despite the BSA Oath to keep myself physically strong , there is a paucity of evidence describing fitness test (FT) outcomes or correlations between FT and variables including age or body mass index (BMI) among Boy Scouts. Therefore, the purpose of this study is to describe and correlate FT to age and BMI among adolescent Boy Scouts. Methods: A prospective study design recruited Boy Scouts aged 11-17 years from Southeast Michigan using a sample of convenience. After securing physician clearance to participate, FT measures were performed utilizing previously established methodology. Third year doctor of physical therapy students trained in the measurement protocol performed the FT measures. Measures encompassed those required for the PFMB: BMI, pull-ups, push-ups, sit and reach flexibility test (SRF), sit-ups, and the one mile run (1MR). Data was analyzed using descriptive statistics, a Kruskal-Wallis test examined relationships between BMI and FT, and a nonparametric Spearman correlation examined correlations between FT performance and both age and BMI with statistical significance set at less than 0.05. Results: Ninety-nine Boy Scouts, whose mean age was 12.6 years (SD 1.4), met the inclusion criteria. The mean BMI was 21.5 (kg/height (cm)) 2 (SD 5.4) with eight scouts meeting criteria of underweight, 56 normal weight, 14 overweight, and 21 obese. Fitness test results were as follows: pull-ups 1.75 (SD 2.7), push-ups 18.0 (SD 10.6), SRF 21.2 cm (SD 10.5), sit-ups 28.9 (SD 8.7), and the 1MR run 616.5 seconds (SD 156.8). When comparing normal weight scouts to overweight and obese scouts, a significantly higher frequency of pull-ups (p=0.002, p=.001), push-ups (p=0.02, p=0.03), sit-ups (p=0.01, p=0.003,), and decreased time for completion on the 1MR (p=0.001, p=0.001) was identified, respectively. Furthermore, while no correlations were identified by age, a negative correlation was identified between increased sit-up frequency (r=-0.36, p=0.001) and decreased 1MR time performance (r=0.39, p=0.001) and a higher BMI. Discussion: While prior evidence suggests improved FT scores in adolescent males with advancing age, this was not observed. Less favorable PFMB required FT performance with an increased BMI among Boy Scouts is in congruence with prior reports for adolescent males. Conclusion: Variations in FT performance levels were observed among Boy Scouts completing the initial FT requirements of the PFMB. However, correlations between higher BMI and less favorable FT performance were detected

Progesterone Treatment Shows Benefit in Female Rats in a Pediatric Model of Controlled Cortical Impact Injury

<div><p>Purpose</p><p>We recently showed that progesterone treatment can reduce lesion size and behavioral deficits after moderate-to-severe bilateral injury to the medial prefrontal cortex in immature male rats. Whether there are important sex differences in response to injury and progesterone treatment in very young subjects has not been given sufficient attention. Here we investigated progesterone’s effects in the same model of brain injury but with pre-pubescent females.</p><p>Methods</p><p>Twenty-eight-day-old female Sprague-Dawley rats received sham (n = 14) or controlled cortical impact (CCI) (n = 21) injury, were given progesterone (8 mg/kg body weight) or vehicle injections on post-injury days (PID) 1–7, and underwent behavioral testing from PID 9–27. Brains were evaluated for lesion size at PID 28.</p><p>Results</p><p>Lesion size in vehicle-treated female rats with CCI injury was smaller than that previously reported for similarly treated age-matched male rats. Treatment with progesterone reduced the effect of CCI on extent of damage and behavioral deficits.</p><p>Conclusion</p><p>Pre-pubescent female rats with midline CCI injury to the frontal cortex have reduced morphological and functional deficits following progesterone treatment. While gender differences in susceptibility to this injury were observed, progesterone treatment produced beneficial effects in young rats of both sexes following CCI.</p></div

Tabulated comparative deficits between male and female controlled cortical impact injury.

<p>Bold numbers with asterisk (<b>*</b>) indicate differences between treatment groups within the same gender, <i>p</i> < .05. Darker-shaded cells indicate where male rats either found the hidden MWM platform faster or made fewer visits to the closed arm of the EPM than similarly treated female rat pups (between-gender analysis), <i>p</i> < .05. Lighter-shaded cells indicate where female rat pups either weighed less, had smaller lesions, spent less time in the open arm of the EPM, tended to travel longer distances (Open Field), remained on the rotarod longer, or found the MWM platform faster than similarly treated male counterparts (b/w gender analysis), <i>p</i> < .05; PID 0 = day of injury but prior to surgery; PID -1 = day(s) before surgery; MWM: Morris Water Maze; CCI: controlled cortical impact; Mean +/- SEM; n = 6–11. Male data (columns 3, 5, 7, and 9) were previously published [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0146419#pone.0146419.ref026" target="_blank">26</a>].</p