Spacecraft drag-free technology development: On-board estimation and control synthesis

Estimation and control methods for a Drag-Free spacecraft are discussed. The functional and analytical synthesis of on-board estimators and controllers for an integrated attitude and translation control system is represented. The framework for detail definition and design of the baseline drag-free system is created. The techniques for solution of self-gravity and electrostatic charging problems are applicable generally, as is the control system development

A Utility Framework for COVID-19 Online Forward Triage Tools: A Swiss Telehealth Case Study.

The SARS-CoV-2 pandemic caused a surge in online tools commonly known as symptom checkers. The purpose of these symptom checkers was mostly to reduce the health system burden by providing worried people with testing criteria, where to test and how to self-care. Technical, usability and organizational challenges with regard to online forward triage tools have also been reported. Very few of these online forward triage tools have been evaluated. Evidence for decision frameworks may be of particular value in a pandemic setting where time frames are restricted, uncertainties are ubiquitous and the evidence base is changing rapidly. The objective was to develop a framework to evaluate the utility of COVID-19 online forward triage tools. The development of the online forward triage tool utility framework was conducted in three phases. The process was guided by the socio-ecological framework for adherence that states that patient (individual), societal and broader structural factors affect adherence to the tool. In a further step, pragmatic incorporation of themes on the utility of online forward triage tools that emerged from our study as well as from the literature was performed. Seven criteria emerged; tool accessibility, reliability as an information source, medical decision-making aid, allaying fear and anxiety, health system burden reduction, onward forward transmission reduction and systems thinking (usefulness in capacity building, planning and resource allocation, e.g., tests and personal protective equipment). This framework is intended to be a starting point and a generic tool that can be adapted to other online forward triage tools beyond COVID-19. A COVID-19 online forward triage tool meeting all seven criteria can be regarded as fit for purpose. How useful an OFTT is depends on its context and purpose

Antenna Technology Shuttle Experiment (ATSE)

Numerous space applications of the future will require mesh deployable antennas of 15 m in diameter or greater for frequencies up to 20 GHz. These applications include mobile communications satellites, orbiting very long baseline interferometry (VLBI) astrophysics missions, and Earth remote sensing missions. A Lockheed wrap rip antennas was used as the test article. The experiments covered a broad range of structural, control, and RF discipline objectives, which is fulfilled in total, would greatly reduce the risk of employing these antenna systems in future space applications. It was concluded that a flight experiment of a relatively large mesh deployable reflector is achievable with no major technological or cost drivers. The test articles and the instrumentation are all within the state of the art and in most cases rely on proven flight hardware. Every effort was made to design the experiments for low cost

Changes in Physical Function Following 4-Weeks of Neuromuscular Electrical Stimulation Training in Older Adults

Sarcopenia, the age-related loss of muscle mass and strength, can result in a decline in physical function. Neuromuscular electrical stimulation (NMES) has been shown to induce muscular adaptations that have the potential to translate to functional improvements; however, little is known regarding functional adaptations pre-post short-term NMES training, especially in older adults. PURPOSE: The aim of this study was to determine NMES-induced changes in lower extremity physical function following 4 weeks of an NMES training intervention of the quadriceps muscle in older adults. METHODS: Seventeen healthy, older adults (68.8 ± 1.8 years old) were divided into two groups: NMES (n = 12) and SHAM (n = 5). The NMES group underwent 12, 40-minute NMES training sessions to the quadriceps muscles on each leg 3x/week over 4 weeks, with the stimulation intensity adjusted every 5 minutes, as needed, to achieve a 15% target torque of each participant’s maximal voluntary contraction (MVC). The stimulation parameters consisted of a 60 Hz stimulation frequency and a duty cycle of 10s on and 15s off. The SHAM group was blinded and did not receive any treatment. The following functional assessments were measured before and after the 4-week training period: Timed Up and Go (TUG), 5x Sit-to-Stand (5XSTS), Stair Climb (SC), and 6-Minute Walk Test (6MWT). Repeated-measures ANOVAs were used to determine changes in TUG, 5XSTS, SC, and 6MWT assessments pre-post NMES training and data are reported as mean ± SE. Statistical significance was set at P \u3c 0.05. RESULTS: NMES training significantly improved TUG (NMES: 8.81 ± 0.54s vs. 7.67 ± 0.39s; P = 0.002; SHAM: 10.60 ± 2.41 vs. 10.93 ± 3.01s; P = 0.652; pre- and post-training, respectively) and SC (NMES: 4.03 ± 0.20s vs. 3.76 ± 0.16s; P = 0.023; SHAM: 6.53 ± 2.11 vs. 6.0 ± 1.78s; P = 0.215; pre- and post-training, respectively); however, 5XSTS (NMES: 9.70 ± 0.75 vs. 8.83 ± 0.72; P \u3e 0.05; SHAM: 14.34 ± 3.64 vs. 13.28 ± 3.89; P \u3e 0.05; pre- and post-training, respectively) and 6MWT (NMES: 610.10 ± 22.68 vs. 623.74 ± 14.73; P \u3e 0.05; SHAM: 533.43 ± 82.44 vs. 587.81 ± 80.52; P \u3e 0.05; pre- and post-training, respectively) did not change following the NMES intervention. CONCLUSION: Improvements in TUG and SC following 4 weeks of NMES training demonstrate augmented lower body physical function, suggesting that short-term NMES training programs may induce neuromuscular adaptations that contribute to these early improvements in physical function in older adults

Resistance Training may Mitigate Age-related Decline in Physical Function

Aging is often accompanied with the onset of sarcopenia, defined by low muscle mass, strength, and physical function. Regular resistance exercise may mitigate this loss; however, data are lacking that compare younger and older adults who do and do not perform resistance training for general health on skeletal muscle mass and physical function. PURPOSE: The aim of this study was to identify differences in muscle mass and physical function between younger and older adults who did and did not perform resistance training for general health. METHODS: Healthy younger (23.8 ± 0.4 yrs) and older (68.5 ± 1.2 yrs) men and women (n = 76) who either did or did not regularly participate in resistance training were placed into 4 groups: young trained (YT: n = 22), young not trained (YNT: n = 16), old trained (OT: n = 17), and old not trained (ONT: n = 21). Dual energy x-ray absorptiometry assessed appendicular skeletal muscle mass (SMI). Participants performed 4 physical function tests: stair climb (SC), 30s sit-to-stand (30sSTS), 6-min walk test (6MWT), and timed-up-and-go (TUG). ANOVAs were used to compare groups for all measures, p ≤ 0.05. Data are reported as mean ± SE. RESULTS: Differences were found between groups for SMI, SC, 30sSTS, 6MWT, and TUG (p ≤ 0.05). SMI was higher for YT compared to YNT (p = 0.001), ONT (p \u3c 0.0001) and OT (p = 0.032) (YT: 8.67 ± 0.36 kg/m2, YNT: 7.08 ± 0.23 kg/m2, OT: 7.73 ± 0.29 kg/m2, ONT: 7.11 ± 0.27 kg/m2). SC performance was slower for ONT compared to YT (p \u3c 0.0001), YNT (p \u3c 0.0001), and OT (p = 0.032); however, YT and was faster than OT (p = 0.002) (YT: 2.37 ± 0.05s, YNT: 2.60 ± 0.10s, OT: 2.94± 0.15s, ONT: 3.32 ± 0.16s). For 30sSTS, OT completed more reps than ONT (p \u3c 0.0001) and YNT (p = 0.001). YT completed more reps than YNT (p \u3c 0.0001) and ONT (p \u3c 0.0001) (YT: 22.8 ± 0.5 reps, YNT: 18.4 ± 0.7 reps, OT: 22.1 ± 1.1 reps, ONT: 16.7 ± 0.6 reps). OT (p = 0.001), YT (p \u3c 0.0001), and YNT (p = 0.046) walked farther in the 6MWT compared to ONT, and YT walked farther than YNT (p = 0.048) (YT: 837.0 ± 16.7 yds, YNT: 783.2 ± 14.5 yds, OT: 819.9 ± 23.3 yds, ONT: 728.3 ± 18.9 yds). For TUG, OT (p = 0.001) and YT (p = 0.046) were faster than ONT (YT: 5.81 ± 0.17s, YNT: 5.87 ± 0.25s, OT: 5.31 ± 0.19s, ONT: 6.35 ± 0.21s). 30sSTS, 6MWT and TUG were not different between OT and YT. 6MWT and SC were not different between OT and YNT (p \u3e 0.05). All other comparisons were not significantly different (p \u3e 0.05). CONCLUSION: Resistance trained older adults outperformed their nonresistance trained peers and these data suggest that older adults who engage in regular resistance training may maintain physical function similar to that of younger adults

Effects and utility of an online forward triage tool during the SARS-CoV-2 pandemic: a mixed method study and patient perspectives, Switzerland.

OBJECTIVE To assess the effects (quantitatively) and the utility (qualitatively) of a COVID-19 online forward triage tool (OFTT) in a pandemic context. DESIGN A mixed method sequential explanatory study was employed. Quantitative data of all OFTT users, between 2 March 2020 and 12 May 2020, were collected. Second, qualitative data were collected through key informant interviews (n=19) to explain the quantitative findings, explore tool utility, user experience and elicit recommendations. SETTING The working group e-emergency medicine at the emergency department developed an OFTT, which was made available online. PARTICIPANTS Participants included all users above the age of 18 that used the OFTT between 2 March 2020 and 12 May 2020. INTERVENTION An OFTT that displayed the current test recommendations of the Federal Office of Public Health on whether someone needed testing for COVID-19 or not. No diagnosis was provided. RESULTS In the study period, 6272 users consulted our OFTT; 40.2% (1626/4049) would have contacted a healthcare provider had the tool not existed. 560 participants consented to a follow-up survey and provided a valid email address. 31.4% (176/560) participants returned a complete follow-up questionnaire. 84.7% (149/176) followed the recommendations given. 41.5% (73/176) reported that their fear was allayed after using the tool. Qualitatively, seven overarching themes emerged namely (1) accessibility of tool, (2) user-friendliness of tool, (3) utility of tool as an information source, (4) utility of tool in allaying fear and anxiety, (5) utility of tool in medical decision-making (6) utility of tool in reducing the potential for onward transmissions and (7) utility of tool in reducing health system burden. CONCLUSION Our findings demonstrated that a COVID-19 OFTT does not only reduce the health system burden but can also serve as an information source, reduce anxiety and fear, reduce potential for cross infections and facilitate medical decision-making