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Objective We assessed operator performance during a real-time reactive telerobotic lunar mission simulation to understand how daytime versus nighttime operations might affect sleepiness, performance, and workload. Background Control center operations present factors that can influence sleepiness, neurobehavioral performance, and workload. Each spaceflight mission poses unique challenges that make it difficult to predict how long operators can safely and accurately conduct operations. We aimed to evaluate the performance impact of time-on-task and time-of-day using a simulated telerobotic lunar rover to better inform staffing and scheduling needs for the upcoming Volatiles Investigating Polar Exploration Rover (VIPER) mission. Methods We studied seven trained operators in a simulated mission control environment. Operators completed two five-hour simulations in a randomized order, beginning at noon and midnight. Performance was evaluated every 25 minutes using the Karolinska Sleepiness Scale, Psychomotor Vigilance Task, and NASA Task Load Index. Results Participants rated themselves as sleepier (5.06 ± 2.28) on the midnight compared to the noon simulation (3.12 ± 1.44; p < .001). Reaction time worsened over time during the midnight simulation but did not vary between simulations. Workload was rated higher during the noon (37.93 ± 20.09) compared to the midnight simulation (32.09 ± 21.74; p = .007). Conclusion Our findings suggest that work shifts during future operations should be limited in duration to minimize sleepiness. Our findings also suggest that working during the day, when distractions are present, increases perceived workload. Further research is needed to understand how working consecutive shifts and taking breaks within a shift influence performance.

Objective: Our goals were to compare three techniques for performing a psychomotor vigilance task (PVT) on a touch screen device (fifth-generation iPod) and to determine the device latency. Background: The PVT is a reaction-time test that is sensitive to sleep loss and circadian misalignment. Several PVT tests have been developed for touch screen devices, but unlike the standard PVT developed for laboratory use, these tests allow for touch responses to be recorded at any location on the device, with contact from any finger. In addition, touch screen devices exhibit latency in processing time between the touch response and the time registered by the device. Method: Thirteen participants completed a 5-min PVT on a touch screen device held in three positions (on a table with index finger, handheld portrait with index finger, handheld landscape with thumb). We compared reaction-time outcomes in each orientation condition using paired t tests. We recorded the first session using a high-speed video camera to determine the latency between the touch response and the documented response time. Results: The participants had significantly faster reaction times in the landscape-oriented position using the thumb, compared with the portrait-oriented position using the index ( M = 224.13 and M = 244.26, p = .045). Using data from 1,241 unique touch events, we found a mean device latency of 68.53 ms that varied highly between individuals. Conclusion: Device orientation and device latency should be considered when using a touch screen version of a PVT. Application: Our findings apply to researchers administering touch screen versions of the PVT.

To access publisher's full text version of this article, please click on the hyperlink in Additional Links field or click on the hyperlink at the top of the page marked Files. This article is open access. ; Melatonin has anticarcinogenic properties in experimental models. We undertook a case-cohort study of 928 Icelandic men without prostate cancer (PCa) nested within the Age, Gene/Environment Susceptibility (AGES)-Reykjavik cohort to investigate the prospective association between first morning-void urinary 6-sulfatoxymelatonin (aMT6s) levels and the subsequent risk for PCa, under the hypothesis that men with lower aMT6s levels have an increased risk for advanced PCa. We used weighted Cox proportional hazards models to assess the association between first morning-void aMT6s levels and PCa risk, adjusting for potential confounders. A total of 111 men were diagnosed with incident PCa, including 24 with advanced disease. Men who reported sleep problems at baseline had lower morning aMT6s levels compared with those who reported no sleep problems. Men with morning aMT6s levels below the median had a fourfold statistically significant increased risk for advanced disease compared with men with levels above the median (hazard ratio: 4.04; 95% confidence interval, 1.26-12.98). These results require replication in larger prospective studies with longer follow-up. ; In this report, we evaluated the prospective association between urinary aMT6s levels and risk of PCa in an Icelandic population. We found that lower levels of aMT6s were associated with an increased risk for advanced PCa. ; RANNIS (the Icelandic Research Fund) National Institutes of Health (NIH) National Center for Research Resources UL1-RR-025758 KL2-RR-025757 Icelandic Cancer Society NIH National Cancer Institute R25-CA-098566 T32-CA-09001-35 Prostate Cancer Foundation NIH National Institutes on Aging (NIA) N01-AG-12100 Icelandic Heart Association Icelandic Parliament NIH NIA P01-AG-009975