Hirschhorn's identities

We prove a general identity between power series and use this identity to give proofs of a number of identities proposed by M.D. Hirschhorn. We also use the identity to give proofs of a well-known result of Jacobi, the quintuple-product identity and Winquist's identit

US/Russian Joint Film Test

A joint U.S./Russian film test was conducted during MIR Mission 18 to evaluate the effects of radiation on photographic film during long-duration space flights. Two duplicate sets of film were flown on this MIR mission: one set was processed and evaluated by the NASA/JSC Photographic Laboratory, and the other by the RKK Energia's Photographic Laboratory in Moscow. This preliminary report includes only the results of the JSC evaluation (excluding the SN-10 film which was not available for evaluation at the time this report was written). The final report will include an evaluation by JSC of the SN-10 film and an evaluation of the test data by the RKK Energia. ISC's evaluation of the test data showed the positive film flown was damaged very little when exposed to approximately 8 rads of radiation. Two of the three negative films were significantly damaged and the third film was damaged only moderately

The Role of Machine Learning in Improved Functionality of Lower Limb Prostheses

Lower-limb amputations can cause a plethora of obstacles that lead to a lower quality of life. Implementing machine learning techniques means advanced prosthetics can contribute to facilitating the lives of those that live with lower-limb amputations. Using the publicly available HuGaDB data set, the current study investigates several classification models (random forest, neural network, and Vowpal Wabbit) to predict the locomotive intentions of individuals using lower-limb prostheses. The results of this study show that the neural network model yielded the highest accuracy, comparable precision, and recall scores to the other models. However, the Vowpal Wabbit model\u27s advantage in speed may allow for other, more practical implementations in practice. These findings provide insight into the advantages of specific classification models over others in predicting the intentions of specific movements during locomotive transitions. These findings present direct comparisons of several machine learning methods, identifying the strengths and weaknesses of each classification model tested

Evaluating K-16 Student Engagement In STEM-based Drone Racing

Increasing the number of students interested in pursuing careers in STEM, computer science, and technology is of widespread interest to education stakeholders. Yet, despite the tremendous amount of human and fiscal resources directed at increasing the STEM, CS, and CTE career pipelines, numbers are less than satisfying. In a purposeful effort to create a more rapid onramp to high tech careers, the project team implemented a series of competitive, quadcopter drone races for students. In these races, student drone pilots race through a timed obstacle course to determine which pilots navigate the challenge in the shortest amount of time. These events that served as a focal point for motivating students to learn about drone technology, encouraging students to develop precision flight skills, and providing educators both inside and outside of formal classrooms with a foundational structure to increase the quantity and quality of technology education. Assessment of students’ and educators’ perceptions suggest that the developed program provided a low barrier to entry and engagement pathway for students to become more deeply engaged in technology

The effect of dietary intake, physical activity and posture on pepsin concentrations detected in the saliva of free-living, healthy individuals

Introduction: Diet and lifestyle are believed to be major causes of gastric reflux. The occurrence of reflux is associated with a number of respiratory, oesophageal and airways conditions. Previous studies have used oesophageal monitoring to assess the occurrence of reflux events. Such measurements may only measure "bulk" rather than "microreflux" events. Such technology is also likely to impact on both habitual dietary intake and physical activity due to the nature of the assessment. Aim: To assess the impact of meal intake and physical activity on pepsin concentrations in saliva collected from free-living individuals throughout the day. Methods: Fifty-one participants (aged 18+, non-smokers with no current chronic or acute respiratory conditions, bloodborne diseases, or diagnosis of reflux disease) provided saliva samples before (< 30 min) and after (< 1 h) meals and physical activity bouts or before and after sleep. Dietary intake and physical activity were monitored by diary over this time. Dietary intake was analyzed using Windiets® software, while physical activity output was calculated from pre-existing tables of energy expenditure. Saliva samples were analyzed for pepsin content using a previously described ELISA methodology. Wilcoxon matched pairs rank sign tests were performed on before- and after-meal/physical activity/sleep samples. Results: Fifty-seven paired pre-and post-meal,48 paired pre- and post-physical activity samples and 168 pre- and post-sleep samples were analyzed. Mean(standard deviation) pepsin concentrations in saliva were significantly higher (P=0.037) in the pre-meal samples (44.2(42.2)) than the post-meal samples (32.8(29.6)). Post-sleep pepsin concentrations (196.4(323.4)) were significantly higher (P< 0.001) than pre-sleep (102.3(152.8)). There was no significant difference (P=0.491) between pre-(45.2(56.8)) and post-(40.8(38.6)) physical activity saliva samples. Conclusions: Analysis of pepsin in saliva is a useful method to assess the impact of lifestyle on reflux event occurrence. Increased preprandial salivary pepsin concentrations may be due to microreflux events driven by the cephalic phase of digestion

The large‐scale freshwater cycle of the Arctic

This paper synthesizes our understanding of the Arctic\u27s large‐scale freshwater cycle. It combines terrestrial and oceanic observations with insights gained from the ERA‐40 reanalysis and land surface and ice‐ocean models. Annual mean freshwater input to the Arctic Ocean is dominated by river discharge (38%), inflow through Bering Strait (30%), and net precipitation (24%). Total freshwater export from the Arctic Ocean to the North Atlantic is dominated by transports through the Canadian Arctic Archipelago (35%) and via Fram Strait as liquid (26%) and sea ice (25%). All terms are computed relative to a reference salinity of 34.8. Compared to earlier estimates, our budget features larger import of freshwater through Bering Strait and larger liquid phase export through Fram Strait. While there is no reason to expect a steady state, error analysis indicates that the difference between annual mean oceanic inflows and outflows (∼8% of the total inflow) is indistinguishable from zero. Freshwater in the Arctic Ocean has a mean residence time of about a decade. This is understood in that annual freshwater input, while large (∼8500 km3), is an order of magnitude smaller than oceanic freshwater storage of ∼84,000 km3. Freshwater in the atmosphere, as water vapor, has a residence time of about a week. Seasonality in Arctic Ocean freshwater storage is nevertheless highly uncertain, reflecting both sparse hydrographic data and insufficient information on sea ice volume. Uncertainties mask seasonal storage changes forced by freshwater fluxes. Of flux terms with sufficient data for analysis, Fram Strait ice outflow shows the largest interannual variability