SCRL-Model for Human Space Flight Operations Enterprise Supply Chain

Standard approach to evaluate and configure adaptable and sustainable program and mission supply chains at an enterprise level. End-to-end view. Total Lifecycle. Evaluate the readiness of the supply chain during the supply chain development phase

The Effects of Forest Harvesting on Small Mammals in Western Newfoundland and its Significance to Marten

The depauperate fauna of Newfoundland provides a limited prey base for marten. Only two small mammal prey species, Microtus pennsylvanicus and Sorex cinereus, were found in any abundance in the old-growth forests of the study area. Of these two, Microtus displayed population fluctuations typical of most microtines. Analysis of marten scats indicated that Microtus is a very important prey item to the marten with other food. items being of lesser importance particularly when Microtus are abundant. Trapping in various habitats indicated that Sorex densities were three to five times higher in logged areas compared to uncut areas. Unfortunately, the effects of logging on Microtus could not be determined directly from this study. Microtus numbers declined drastically in the spring of 1987, apparently independently of logging operations. Microtus numbers dropped from a density of 25.0 per hectare in the spring of 1986 to virtually zero in the spring of 1987. This reduction may be linked to an outbreak of viral encephalitus in the marten population in the fall of 1986. Marten (Martes arnericana) prefer mature coniferous and mixed forests and utilize regenerating cutovers minimally. The reasons for this are unclear, although prey abundance and availability may be involved. In this study, Sorex were more abundance in regenerating cutovers and the literature suggests that Microtus are also more abundant in these areas. This would seem to suggest that prey abundance above certain threshold densities is not critical to marten habitat selection. However, prey availability may play a more important role. Although prey species may be more abundance in logged areas, prey availability may be reduced

Investigation of the effects of shrinkage, creep, and abrasion on self-consolidating concrete and high volume fly ash concrete for use in transportation related infrastructure

Concrete specimens were fabricated for shrinkage, creep, and abrasion resistance testing. Variations of self-consolidating concrete (SCC), high volume fly ash concrete (HVFA), and conventional concrete were studied. The results were compared to previous similar testing programs and used to determine the adequacy of the materials for use in practice. These two concrete variations offer significant benefits when used as replacements to conventional concrete. Because of the respective properties of both types of concrete, both economic and environmental benefits are achieved with the use of both. The lower labor costs of SCC and the lower material cost of HVFA lead to lower overall construction costs, while the decrease in CO₂ production and conservation of landfill space through the use of HVFA lead to significant environmental benefits. The SCC testing program consisted of normal strength (6000 psi) and high strength (10,000 psi) variations of SCC and conventional concrete. The HVFA testing program consisted of two variations of HVFA with 70% fly ash replacement and one conventional concrete mix. All specimens were tested for compressive strength, modulus of elasticity, shrinkage strain, creep strain, and abrasion resistance. All tests were performed according to their respective ASTM standard methods. SCC performed well relative to convention concrete at high strengths, but not as well at normal strengths for shrinkage and creep. HVFA, however, outperformed conventional concrete in both shrinkage and creep. Abrasion resistance was primarily dependant [sic] on concrete strength, not concrete type --Abstract, page iii

Exploring Teacher and Student Experiences In a Nature-Based Mathematical Environment

This research study explored the experiences of this teacher-researcher and eight student-participants in a Montessori-inspired, nature-based mathematical environment. I utilized an action research study framework with a critical event narrative analysis to describe mine and my student-participants’ experiences throughout this study, using Uhrmacher et al.’s (2017) instructional arc as a guide. I restoried each participants’ lived and told stories as the curriculum seamlessly moved through the arc: intended to operational to received curriculum. The restoried narratives revolved around the identified critical events each participant experienced throughout the mathematical learning experience. The multiple restoried narratives required data collection that included observations, documents, interviews, and photographs to understand and interpret the different and unique experiences of each participant. Findings of this study suggest that students are able to see the mathematical connections in nature with a noted reduction in their mathematical anxiety and increase in their productivity while learning and creating piecewise-defined mathematical equations outside. In addition, this study found that prior experiences influenced this teacher-researcher’s curriculum design planning and these student-participants’ ability to access their prior mathematical knowledge

Glutamate receptor-mediated taurine release from the hippocampus during oxidative stress

<p>Abstract</p> <p>Background</p> <p>Hippocampal slices swell and release taurine during oxidative stress. The influence of cellular signalling pathways on this process is unclear. Glutamate signalling can facilitate volume regulation in other CNS preparations. Therefore, we hypothesize activation of taurine release by oxidative stress results from tissue swelling and is coupled to activation of glutamate receptors.</p> <p>Methods</p> <p>Rat hippocampi were incubated at room temperature for 2 hr in artificial cerebrospinal fluid (aCSF) equilibrated with 95% O₂ plus 5% CO₂. For some slices, 1 mM taurine was added to the aCSF to maintain normal tissue taurine content. Slices then were perfused with aCSF at 35° C and baseline data recorded before 2 mM H₂O₂ was added. For some studies, mannitol or inhibitors of glutamate receptors or the volume-regulated anion channel (VRAC) were added before and during H₂O₂ treatment. The intensity of light transmitted through the slice (the intrinsic optical signal, IOS) was determined at 1-min intervals. Samples of perfusate were collected at 2-min intervals and amino acid contents determined by HPLC. Data were analyzed by repeated measures ANOVA and <it>post hoc</it> Dunnett’s test with significance indicated for p<0.05.</p> <p>Results</p> <p>IOS of slices prepared without taurine treatment increased significantly by 3.3±1.3% (mean±SEM) during oxidative stress. Little taurine was detected in the perfusate of these slices and the rate of taurine efflux did not change during H₂O₂ exposure. The α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate antagonist, 25 µM CNQX, but not the N-methyl-D-aspartate (NMDA) receptor antagonist, 10 µM MK-801, inhibited the increase in IOS during H₂O₂ treatment. Taurine-treated slices exposed to H₂O₂ showed no change in IOS; however, taurine efflux increased by 335±178%. When these slices were perfused with hypertonic aCSF (350 mOsm) or exposed to the VRAC inhibitor, 20 µM DCPIB, no increase in the taurine efflux rate was observed during H₂O₂ exposure. Taurine-treated slices perfused with 10 µM MK-801 during H₂O₂ exposure showed a 4.6±1.9% increase in IOS but no increase in the taurine efflux rate.</p> <p>Conclusions</p> <p>Taurine efflux via VRAC is critical for volume regulation of hippocampal slices exposed to oxidative stress. This increased taurine efflux does not result from direct activation of the taurine release pathway by H₂O₂. NMDA receptor activation plays an important role in taurine release during oxidative stress.</p