Parkes radio science system design and testing for Voyager Neptune encounter

The Radio Science System installed at Parkes, Australia for the Voyager Neptune encounter was specified to meet the same stringent requirements that were imposed upon the Deep Space Network Radio Science System. The system design and test methodology employed to meet these requirements at Parkes are described, and data showing the measured performance of the system are presented. The results indicate that the system operates with a comfortable margin on the requirements. There was a minor problem with frequency-dependent spurious signals which could not be fixed before the encounter. Test results characterizing these spurious signals are included

DSN radio science system design and testing for Voyager-Neptune encounter

The Deep Space Network (DSN) Radio Science System presently implemented within the Deep Space Network was designed to meet stringent requirements imposed by the demands of the Voyager-Neptune encounter and future missions. One of the initial parameters related to frequency stability is discussed. The requirement, specification, design, and methodology for measuring this parameter are described. A description of special instrumentation that was developed for the test measurements and initial test data resulting from the system tests performed at Canberra, Australia and Usuda, Japan are given

A Comparison of Aquatic- vs. Land-Based Plyometrics on Various Performance Variables

International Journal of Exercise Science 8(2) : 134-144, 2015. The purpose of this study was to compare the effects of an aquatic- (W) and land-based (L) plyometric program on balance, vertical jump height, and isokinetic quadriceps and hamstring strength. Thirty-four participants were randomized into three groups, W (n = 12), L (n = 11), and control (n = 11). The W and L groups completed an eight-week plyometric program. A two-way repeated measures ANOVA revealed a significant main effect of condition (F = 346.95, p \u3c 0.001) and interaction between condition by time (F = 1.88, p = 0.01). Paired samples t-tests revealed statistically significant improvements from pre- to post-testing in the L group for isokinetic quadriceps strength at 60 degrees per second (p = 0.02) and hamstring strength at 120 degrees per second (p = 0.02). Statistically significant improvements were observed from pre- to post-testing in the W group for balance (p = 0.003), vertical jump height (p = 0.008), isokinetic quadriceps strength at 60 and 120 degrees per second (p \u3c 0.001), and hamstring strength at 120 degrees per second (p = 0.03). Results demonstrate that aquatic-based plyometric training can be a valid form of training by producing improvements in balance, force output, and isokinetic strength while concurrently decreasing ground impact forces

The Effects of a 12-Week Faculty and Staff Exercise Program on Health-Related Variables in a University Setting

International Journal of Exercise Science 8(1) : 49-56, 2015. The obesity epidemic has grown in the past decade due to physical inactivity (i.e., having a sedentary job) and an increase in caloric intake. This problem combined with the reluctance of many faculty and staff members exercising in the same environment as student’s presents a unique challenge in an academic setting. The purpose of this study was to examine the effectiveness of a 12-week exercise program focused toward the faculty and staff in improving several health-related variables such as curl-ups, push-ups, sit-and-reach, and balance. Fifty-seven faculty and staff participated in the current study. Participants engaged in a variety of exercise classes taught by certified instructors three days a week for 12-weeks. Paired samples t-tests illustrated a significant (p \u3c 0.001) decrease in body mass and significant (p \u3c 0.001) improvements in curl-ups, push-ups, sit-and-reach, and balance. This data demonstrates that a 12-week faculty and staff exercise program has the potential to improve performance in several health-related variables such as curl-ups, push-ups, sit-and-reach, and balance. The ability of this program to improve health-related variables and possibly delay or prevent the development of overweight and/or obesity, sarcopenia, and other chronic diseases is encouraging

The Mars Observer Ka-band link experiment

The Ka-Band Link Experiment was the first demonstration of a deep-space communications link in the 32- to 35-GHz band (Ka-band). It was carried out using the Mars Observer spacecraft while the spacecraft was in the cruise phase of its mission and using a 34-meter beam-waveguide research and development antenna at the Goldstone complex of the DSN. The DSN has been investigating the performance benefits of a shift from X-band (8.4 GHz) to Ka-band (32 GHz) for deep-space communications. The fourfold increase in frequency is expected to offer a factor of 3 to 10 improvement (5 to 10 dB) in signal strength for a given spacecraft transmitter power and antenna size. Until recently, the expected benefits were based on performance studies, with an eye to implementing such a link, but theory was transformed to reality when a 33.7-GHz Ka-band signal was received from the spacecraft by DSS 13. This article describes the design and implementation of the Ka-Band Link Experiment from the spacecraft to the DSS-13 system, as well as results from the Ka-band telemetry demonstration, ranging demonstration, and long-term tracking experiment. Finally, a preliminary analysis of comparative X- and Ka-band tracking results is included. These results show a 4- to 7-dB advantage for Ka-band using the system at DSS 13, assuming such obstacles as antenna pointing loss and power conversion loss are overcome

The Physiologic and Behavioral Implications of Playing Active and Sedentary Video Games in a Seated and Standing Position

International Journal of Exercise Science 7(3) : 194-201, 2014. Previous studies have assessed physiologic response while playing video games per manufacturer instructions with participants standing during active video game play and seated during sedentary game play. It is not known whether an assigned seated or standing position affects positional preference and oxygen consumption (VO2) while gaming. The purpose of the study was to assess VO2 and preference of playing active and sedentary video games in a seated and standing position. VO2 was assessed in 25 participants during four, 20-minute conditions; resting, PlayStation 2 Madden NFL Football 2011, Nintendo Wii-Sports Boxing and Nintendo Wii Madden NFL Football 2011. Each condition was divided into two positional conditions (10 minutes seated, 10 minutes standing) and each participant indicated their positional preference after each 20-minute condition. Standing VO2 (4.4 ± 0.2 ml•kg-1•min-1 PS2, 4.6 ± 0.1 ml•kg-1•min-1 Wii Madden, 6.8 ± 0.3 ml•kg-1•min-1Wii Boxing) was significantly (p ≤ 0.001) greater than seated VO2 (4.0 ± 0.1 ml•kg-1•min-1 PS2, 4.2 ± 0.1 ml•kg-1•min-1 Wii Madden, 6.1 ± 0.3 ml•kg-1•min-1Wii Boxing) for each gaming condition. Participants preferred (p ≤ 0.001) to sit for all gaming conditions except Wii Boxing. Playing video games while standing increases VO2 to a greater extent than playing the same games in a seated position. Standing was only preferred for the most physiologically challenging game, Wii Boxing. Gaming position should be considered when assessing the physiologic and behavioral outcomes of playing video games

The Impact of Cell Phone Texting During Aerobic Exercise on Measures of Cognition

International Journal of Exercise Science 12(5): 646-656, 2019. This study assessed the effect of cell phone texting during a 30-minute bout of cycle ergometer exercise on measures of cognition (i.e., reaction time and accuracy). Twenty-eight college students participated in two conditions (cell phone and no cell phone). Reaction time and accuracy were assessed pre- and post-exercise with the use of the Stroop test. Reaction time was significantly worse (p \u3c 0.001) in the cell phone condition from pre- (1003.75 ± 178.04 ms) to post-exercise (1124.46 ± 238.55 ms). Reaction time was significantly better (p \u3c 0.001) in the no cell phone condition from pre- (1107.71 ± 229.54 ms) to post-exercise (953.86 ± 177.42 ms). Accuracy was significantly worse (p = 0.01) in the cell phone condition from pre- (97.61 ± 2.32) to post-exercise (94.04 ± 7.88). Accuracy was significantly better (p \u3c 0.001) in the no cell phone condition from pre- (94.82 ± 4.42) to post-exercise (97.39 ± 2.42). In conclusion, using your cell phone for texting can interfere with the cognitive benefits associated with reaction time and accuracy that are developed from participating in aerobic exercise

Increased Physical Activity and Reduced Pain with Spinal Cord Stimulation: a 12-Month Study

International Journal of Exercise Science 13(3): 1583-1594, 2020. The purpose of this study was to assess changes in pain and physical activity after replacing a traditional spinal cord stimulation (SCS) implantable pulse generator with a next generation SCS in patients for whom traditional SCS was no longer providing adequate relief of low back and/or leg pain. Subjects (n = 19) who reported that they were no longer receiving adequate relief from traditional SCS were implanted with a next generation SCS. Eighteen additional patients who were receiving relief from traditional SCS were also followed as a control. Both groups (next generation, traditional) were assessed for low-back and limb pain (visual analog scale) and daily physical activity (wearable accelerometer) at baseline and three, six, nine and 12 months following the SCS implant. Relative to baseline, next generation SCS subjects exhibited reductions (p ≤ 0.05 for all) in low-back pain (average reduction of 22%) at every time point, in leg pain (average reduction of 23%) at every time point except six months and increased physical activity (average increase of 57%) at three, six and nine months. As expected, there were no changes in pain or physical activity in the traditional SCS subjects (p ≥ 0.1). In conclusion, pain decreased, and physical activity increased in patients receiving a next generation SCS. Physical activity may serve as an objectively measured marker of pain

Impact of Cell Phone Texting on the Amount of Time Spent Exercising at Different Intensities

Please refer to the pdf version of the abstract located adjacent to the title

High-dose Cefepime vs Carbapenems for Bacteremia Caused by Enterobacterales With Moderate to High Risk of Clinically Significant AmpC β-lactamase Production

BACKGROUND: Limited data suggest that serious infections caused by Enterobacterales with a moderate to high risk of clinically significant AmpC production can be successfully treated with cefepime if the cefepime minimum inhibitory concentration (MIC) is ≤2 µg/mL. However, isolates with a cefepime-susceptible dose-dependent (SDD) MIC of 4-8 µg/mL should receive a carbapenem due to target attainment and extended-spectrum β-lactamase (ESBL) concerns. METHODS: This was a retrospective cohort study of hospitalized patients with RESULTS: Of the 315 patients included, 169 received cefepime and 146 received a carbapenem (ertapenem n = 90, meropenem n = 56). Cefepime was not associated with an increased risk of 30-day mortality compared with carbapenem therapy (adjusted hazard ratio [aHR], 1.45; 95% CI, 0.79-2.14), which was consistent for patients with cefepime SDD isolates (aHR, 1.19; 95% CI, 0.52-1.77). Multivariable weighted Cox models identified Pitt bacteremia score \u3e4 (aHR, 1.41; 95% CI, 1.04-1.92), deep infection (aHR, 2.27; 95% CI, 1.21-4.32), and ceftriaxone-resistant AmpC-E (aHR, 1.32; 95% CI, 1.03-1.59) to be independent predictors associated with increased mortality risk, while receipt of prolonged-infusion β-lactam was protective (aHR, 0.67; 95% CI, 0.40-0.89). CONCLUSIONS: Among patients with bacteremia caused by Enterobacterales with moderate to high risk of clinically significant AmpC production, these data demonstrate similar risk of 30-day mortality for high-dose cefepime or a carbapenem as definitive β-lactam therapy