History of land use on Alaska's Kenai River and its implications for sustaining salmon

Thesis (Ph.D.) University of Alaska Fairbanks, 2014The Kenai River Watershed (KRW), in south-central Alaska, is famous for its salmon. Urbanization along the lower river damages habitat and stresses these valuable fish. Are the river's salmon runs sustainable if recent land-use trends continue? I used interdisciplinary approaches from environmental history and landscape science plus technologies such as geographic information systems (GIS) to describe the watershed's land-use history from 1947 to 2010 and to link land use and watershed management to the sustainability of salmon runs. Although the area appears wild compared to many salmon-producing watersheds in other states, it has a long history of intense use and habitat degradation. Over the past 60 years the central Kenai Peninsula showed patterns of intensive riverfront recreational use, coupled with rural exurban sprawl in the uplands. Historic damage to salmon habitat included trampled riverbanks, bank hardening, dredged canals, diverted creeks, toxic spills, poorly built roads with impassable culverts, and the Cooper Lake Dam. More recent threats include cumulative effects, fishing pressure, climate change, invasive species, off-road vehicles, and potential septic leaks. Comparing the Kenai River case with land-use histories in 60 other salmon-producing watersheds suggested that the salmon runs are at risk due to delayed, cumulative effects of development and potential climate change. However, since the late 1980s people have taken unprecedented and progressive steps to protect healthy watershed habitat and reverse past damage. The high level of community commitment and reserves of undamaged habitat provide hope that Alaskans may learn from the grim fate of wild salmon around the world, and take better care of their salmon habitat. I concluded that the sustainability of the salmon runs hangs in the balance and offer a list of recommendations to maintain or enhance the resilience of the system

Heat and Hypoxic Acclimation Increase Monocyte Heat Shock Protein 72 but Do Not Attenuate Inflammation following Hypoxic Exercise

Acclimation to heat or hypoxic stress activates the heat shock response and accumulation of cytoprotective heat shock proteins (HSPs). By inhibiting the NF-κB pathway HSP72 can preserve epithelial function and reduce systemic inflammation. The aim of this study was to determine the time course of mHSP72 accumulation during acclimation, and to assess intestinal barrier damage and systemic inflammation following hypoxic exercise. Three groups completed 10 × 60-min acclimation sessions (50% normoxic VO2peak) in control (n = 7; 18°C, 35% RH), hypoxic (n = 7; FiO2 = 0.14, 18°C, 35% RH), or hot (n = 7; 40°C, 25% RH) conditions. Tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), interleukin 10 (IL-10), and intestinal fatty acid binding protein (I-FABP) were determined at rest and following a cycling normoxic stress test (NST; ~2 weeks before acclimation), pre-acclimation hypoxic stress test (HST1; FiO2 = 0.14, both at 50% normoxic VO2peak; ~1 week before acclimation) and post-acclimation HST (48 h; HST2). Monocyte HSP72 (mHSP72) was determined before and after exercise on day 1, 3, 5, 6, and 10 of acclimation. Accumulation of basal mHSP72 was evident from day 5 (p < 0.05) of heat acclimation and increased further on day 6 (p < 0.01), and day 10 (p < 0.01). In contrast, basal mHSP72 was elevated on the final day of hypoxic acclimation (p < 0.05). Following the NST, plasma TNF-α (–0.11 ± 0.27 ng.mL−1), IL-6 (+0.62 ± 0.67 ng.mL−1) IL-10 (+1.09 ± 9.06 ng.mL−1) and I-FABP (+37.6 ± 112.8 pg.mL−1) exhibited minimal change. After HST1, IL-6 (+3.87 ± 2.56 ng.mL−1), IL-10 (+26.15 ± 26.06 ng.mL−1) and I-FABP (+183.7 ± 182.1 pg.mL−1) were elevated (p < 0.01), whereas TNF-α was unaltered (+0.08 ± 1.27; p > 0.05). A similar trend was observed after HST2, with IL-6 (+3.09 ± 1.30 ng.mL−1), IL-10 (+23.22 ± 21.67 ng.mL−1) and I-FABP (+145.9 ±123.2 pg.mL−1) increased from rest. Heat acclimation induces mHSP72 accumulation earlier and at a greater magnitude compared to matched work hypoxic acclimation, however neither acclimation regime attenuated the systemic cytokine response or intestinal damage following acute exercise in hypoxia

Changes in appetite, energy intake, body composition and circulating ghrelin constituents during an incremental trekking ascent to high altitude

Purpose Circulating acylated ghrelin concentrations are associated with altitude-induced anorexia in laboratory environments, but have never been measured at terrestrial altitude. This study examined time course changes in appetite, energy intake, body composition, and ghrelin constituents during a high-altitude trek. Methods Twelve participants [age: 28(4) years, BMI 23.0(2.1) kg m−2] completed a 14-day trek in the Himalayas. Energy intake, appetite perceptions, body composition, and circulating acylated, des-acylated, and total ghrelin concentrations were assessed at baseline (113 m, 12 days prior to departure) and at three fixed research camps during the trek (3619 m, day 7; 4600 m, day 10; 5140 m, day 12). Results Relative to baseline, energy intake was lower at 3619 m (P = 0.038) and 5140 m (P = 0.016) and tended to be lower at 4600 m (P = 0.056). Appetite perceptions were lower at 5140 m (P = 0.027) compared with baseline. Acylated ghrelin concentrations were lower at 3619 m (P = 0.046) and 4600 m (P = 0.038), and tended to be lower at 5140 m (P = 0.070), compared with baseline. Des-acylated ghrelin concentrations did not significantly change during the trek (P = 0.177). Total ghrelin concentrations decreased from baseline to 4600 m (P = 0.045). Skinfold thickness was lower at all points during the trek compared with baseline (P ≤ 0.001) and calf girth decreased incrementally during the trek (P = 0.010). Conclusions Changes in plasma acylated and total ghrelin concentrations may contribute to the suppression of appetite and energy intake at altitude, but differences in the time course of these responses suggest that additional factors are also involved. Interventions are required to maintain appetite and energy balance during trekking at terrestrial altitudes

Labelling and optical erasure of synaptic memory traces in the motor cortex

Dendritic spines are the major loci of synaptic plasticity and are considered as possible structural correlates of memory. Nonetheless, systematic manipulation of specific subsets of spines in the cortex has been unattainable, and thus, the link between spines and memory has been correlational. We developed a novel synaptic optoprobe, AS-PaRac1 (activated synapse targeting photoactivatable Rac1), which can label recently potentiated spines specifically, and induce the selective shrinkage of AS-PaRac1-containing spines. In vivo imaging of AS-PaRac1 revealed that a motor learning induced substantial synaptic remodelling in a small subset of neurons. The acquired motor learning was disrupted by the optical shrinkage of the potentiated spines, whereas it was not affected by the identical manipulation of spines evoked by a distinct motor task in the same cortical region. Taken together, our results demonstrate that a newly acquired motor skill depends on the formation of a task-specific dense synaptic ensemble

Improving the assessment of transferable skills in chemistry through evaluation of current practice

The development and assessment of transferable skills acquired by students, such as communication and teamwork, within undergraduate degrees is being increas-ingly emphasised. Many instructors have designed and implemented assessment tasks with the aim to provide students with opportunities to acquire and demon-strate these skills. We have now applied our previously published tool to evaluate whether assessment tasks allow students to demonstrate achievement of these transferable skills. The tool allows detailed evaluation of the alignment of any as-sessment item against the claimed set of learning outcomes. We present here two examples in which use of the tool provides evidence for the level of achievement of transferable skills and a further example of use of the tool to inform curricu-lum design and pedagogy, with the goal of increasing achievement of communi-cation and teamwork bench marks. Implications for practice in assessment design for learning are presented

Gut Microbiome Impacts on the Progression ​and Treatment of Diabetes

Diabetes mellitus is an autoimmune disease that impacts millions of individuals worldwide. Diabetes is treatable and one can live a normal life with this treatment, yet there is still no cure and the exact mechanism through which it develops remains elusive. Diet, environment, genetics, and lifestyle are all factors contributing to the increasing number of diabetes cases, though genetics are being reconsidered as the primary factor. Instead, recent research has turned to the gut microbiome as both a cause of diabetes and a possible treatment and prevention option, with new data elevating the importance. However, this is controversial, because findings remain mixed and additional support is needed, as this manuscript will review. Presently, Type 1 diabetes (T1D) research has found that the microbiome can be used as a biomarker because an increase in alpha-diversity is correlated to a decreased likelihood of developing diabetes. Research has also focused on using the gut microbiome to alleviate symptoms or prevent T1D. On the other hand, Type 2 diabetes (T2D) likely has a partial cause in gut microbiome dysbiosis due to increases in gut permeability and systemic inflammation leading to insulin resistance. However, an increase in beneficial bacteria through probiotics and other dietary changes could provide a reversal of the disease state. Studies still need to be conducted to advance understanding of the exact mechanisms through which gut microbes can trigger or protect from diabetes, using further human clinical studies.  &nbsp

Geeks are CHIC: Cultural identity and engineering students\u27 pathways to the profession

This paper reports findings from a longitudinal study of undergraduate engineering students on their embracing of a campus and disciplinary culture, that of a geek. In analysis of data from the students\u27 first and second years, researchers examine the development of pre-professional engineering identity within the pseudonymous Mountain Technology Institute (MT or Mountain Tech). Authors speculate that despite widespread enjoyment in the first year of finding others - geeks -who share their interests, in the second year, some of MT\u27s undergraduates chafe at the narrowness of their engineering and technology education. Further, the authors postulate that the students who become reluctant to remain geeks throughout their undergraduate careers may be reluctant to remain in the engineering field. © American Society for Engineering Education, 2007

Comparison of Rosetta flexible-backbone computational protein design methods on binding interactions

ABSTRACTComputational design of binding sites in proteins remains difficult, in part due to limitations in our current ability to sample backbone conformations that enable precise and accurate geometric positioning of side chains during sequence design. Here we present a benchmark framework for comparison between flexible-backbone design methods applied to binding interactions. We quantify the ability of different flexible backbone design methods in the widely used protein design software Rosetta to recapitulate observed protein sequence profiles assumed to represent functional protein/protein and protein/small molecule binding interactions. The CoupledMoves method, which combines backbone flexibility and sequence exploration into a single acceptance step during the sampling trajectory, better recapitulates observed sequence profiles than the BackrubEnsemble and FastDesign methods, which separate backbone flexibility and sequence design into separate acceptance steps during the sampling trajectory. Flexible-backbone design with the CoupledMoves method is a powerful strategy for reducing sequence space to generate targeted libraries for experimental screening and selection.</jats:p