Evaluation of Hands-Free Devices for the Display of Maintenance Procedures

Over the past year, NASA's focus has turned to crewed long duration and exploration missions. On these journeys, crewmembers will be required to execute thousands of procedures to maintain life support systems, check out space suits, conduct science experiments, and perform medical exams. To support the many complex tasks crewmembers undertake in microgravity, NASA is interested in providing crewmembers a hands-free work environment to promote more efficient operations. The overarching objective is to allow crewmembers to use both of their hands for tasks related to their mission, versus holding a paper manual or interacting with a display. The use of advanced, hands-free tools will undoubtedly make the crewmembers task easier, but they can also add to overall task complexity if not properly designed. A leading candidate technology for supporting a hands-free environment is the Head-Mounted Display (HMD). A more recent technology (e-book reader) that could be easily temp-stowed near the work area is also a potential hands-free solution. Previous work at NASA involved the evaluation of several commercially available HMDs for visual quality, comfort, and fit, as well as suitability for use in microgravity. Based on results from this work, three HMDs were selected for further evaluation (along with an e-book reader), using International Space Station (ISS)-like maintenance procedures. Two evaluations were conducted in the Space Station Mockup and Trainer Facility (SSMTF) located at the NASA Johnson Space Center (building 9). The SSMTF is a full scale, medium fidelity replica of the pressurized portions of the ISS. It supports crew training such as ingress and egress, habitability, and emergency procedures. In each of the two evaluations, the participants performed two maintenance procedures. One maintenance procedure involved inspecting air filters in a life support system and replacing them with a clean filter if one were found to be contaminated. The second maintenance procedure focused on working in a confined space; specifically, pulling down a rack to inspect wiring configurations, and rewiring in a different pattern. The maintenance procedures were selected to assess mobility, tool use, and access to multiple document sources during task performance. That is, the participant had to move from rack to rack, use a wrench, a camera, etc., replace components, and refer to diagrams to complete tasks. A constraint was imposed that the ISS-like format of the procedures was to be retained, and not modified or optimized for the electronic device ("plug and play" approach). This was based on future plans to test with real procedures on ISS

It's about Time? Testing the Dawson Ceramic Seriation Using Luminescence Dating, Southern Nasca Region, Peru

The Dawson seriation of Nasca ceramics has long been assumed to be an accurate marker of temporal changes in the pre-hispanic south coast of Peru. We test this assumption by directly dating a sample of sherds using Optically Stimulated Luminescence (OSL). Our results suggest that while some phases of the seriation are valid chronological markers, others appear to be the result of factors other than time. We discuss the implications of these results and call for additional studies of ceramics using luminescence dating

Postexercise Muscle Glycogen Synthesis with Combined Glucose and Fructose Ingestion

Purpose: To evaluate the efficacy of using combined glucose and fructose (GF) ingestion as a means to stimulate short-term (4 h) postexercise muscle glycogen synthesis compared to glucose only (G). Methods: On two separate occasions, six endurance-trained men performed an exhaustive glycogen-depleting exercise bout followed by a 4-h recovery period. Muscle biopsy samples were obtained from the vastus lateralis muscle at 0, 1, and 4 h after exercise. Subjects ingested carbohydrate solutions containing G (90 gIhj1) or GF (G = 60 gIhj1; F = 30 gIhj1) commencing immediately after exercise and every 30 min thereafter. Results: Immediate postexercise muscle glycogen concentrations were similar in both trials (G = 128 T 25 mmolIkgj1 dry muscle (dm) vs GF = 112 T 16 mmolIkgj1 dm; P 9 0.05). Total glycogen storage during the 4-h recovery period was 176 T 33 and 155 T 31 mmolIkgj1 dm for G and GF, respectively (G vs GF, P 9 0.05). Hence, mean muscle glycogen synthesis rates during the 4-h recovery period did not differ between the two conditions (G = 44 T 8 mmolIkgj1 dmIhj1 vs GF = 39 T 8 mmolIkgj1 dmIhj1, P 9 0.05). Plasma glucose and serum insulin responses during the recovery period were similar in both conditions, although plasma lactate concentrations were significantly elevated during GF compared to G (by È0.8 mmolILj1, P G 0.05). Conclusions: Glucose and glucose/fructose (2:1 ratio) solutions, ingested at a rate of 90 gIhj1, are equally effective at restoring muscle glycogen in exercised muscles during the recovery from exhaustive exercise