Nights Of Data Research Articles

0262 Comparing Wrist Actigraphy to a Novel Wearable (Actigpatch): Nonparametric Activity Estimation

Abstract Introduction Wrist actigraphy is a standard for monitoring sleep in the field; however, data quality is reduced if participants remove the device. The Actigpatch is a novel, adhesive water-resistant wearable that we have previously demonstrated as comparable to wrist actigraphy for traditional sleep-wake estimation. Here we compare assessment of nonparametric activity indexes. Methods While following fixed schedules, 39 participants simultaneously wore the Micro Motionlogger actigraph (Ambulatory Monitoring Inc., Ardley, NY) on their non-dominant wrist and the Actigpatch (Circadian Positioning Systems, Newport, RI) over the triceps of their dominant arm. Our analyses included 35 participants (21F; 32.9±13.2yrs) who contributed ≥four nights of data (range: 4-14 [mean: 10] nights). After matching devices’ tri-axial actimetry in one-minute epochs, we derived key non-parametric parameters of diurnal activity and calculated intraclass correlations to measure agreement. The non-parametric parameters include interdaily stability (IS), intradaily variability (IV), timing of the five hours of lowest activity (L5onset) and ten hours of highest activity (M10onset), and overall relative amplitude (RA). Results We observed agreement ranging from good for IS (ICC=0.77 [95%CI=0.59;0.88]; [all mean differences are patch-watch] mean difference=-0.21) to poor for IV (ICC=0.43 [0.12;0.67]; mean difference=0.29). ICC showed good agreement for M10onset (ICC=0.82 [0.67; 0.90]; mean difference=-37min) and excellent agreement for L5onset (ICC=0.91 [0.82;0.95]; mean difference=-2min). Finally, we identified good agreement when estimating the activity relative amplitude (RA ICC=0.86 [0.75; 0.93]; mean difference=0.03). An example of excellent agreement was manifested in the close estimation of L5onset (patch mean=1:04am, SD=70min; watch mean=1:06am, SD=68min). Conclusion Adding to our prior evidence that these two devices offer similar sleep-wake estimation using traditional algorithms, the present data indicate the Actigpatch offers good agreement to the Motionlogger for nonparametric analyses of IS, activity timing, and RA. Agreement was not as good for IV, with the Actigpatch showing more intradaily variability than the watch, perhaps due to the triceps placement. Because the Actigpatch is unobtrusive, water-resistant, and can be worn continuously for three weeks, it has potential benefits for studies of individuals who struggle with adherence to wearing wrist worn devices. Support (if any) R01AA025593, P20GM139743. Actigpatches provided by Circadian Positioning Systems.

Assessing the impact of two independent direction-dependent calibration algorithms on the LOFAR 21 cm signal power spectrum

Context. Detecting the 21 cm signal from the epoch of reionisation (EoR) has been highly challenging due to the strong astrophysical foregrounds, ionospheric effects, radio frequency interference (RFI), and instrumental effects. Better characterisation of their effects and precise calibration are, therefore, crucial for the 21 cm EoR signal detection. Aims. In this work we introduce a newly developed direction-dependent calibration algorithm called DDECAL, and compare its performance with an existing direction-dependent calibration algorithm called SAGECAL, in the context of the LOFAR-EoR 21 cm power spectrum experiment. Methods. We process one night of data from LOFAR observed by the HBA system. The observing frequency ranges between 114 and 127 MHz, corresponding to the redshift from 11.5 and 10.2. The north celestial pole (NCP) and its flanking fields were observed simultaneously in this data set. We analyse the NCP and one of the flanking fields. While the NCP field is calibrated by the standard LOFAR-EoR processing pipeline, using SAGECAL for the direction-dependent calibration with an extensive sky model and 122 directions, for the RA 18h flanking field, DDECAL and SAGECAL are used with a relatively simple sky model and 22 directions. Additionally, two different strategies are used for the subtraction of the very bright and far sources Cassiopeia A and Cygnus A. Results. The resulting estimated 21 cm power spectra show that DDECAL performs better at subtracting sources in the primary beam region, due to the application of a beam model, while SAGECAL performs better at subtracting Cassiopeia A and Cygnus A. The analysis shows that including a beam model during the direction-dependent calibration process significantly improves its overall performance. The benefit is obvious in the primary beam region. We also compare the 21 cm power spectra results on two different fields. The results show that the RA 18h flanking field produces better upper limits compared to the NCP for this particular observation. Conclusions. Despite the minor differences between DDECAL and SAGECAL, due to the beam application, we find that the two algorithms yield comparable 21 cm power spectra on the LOFAR-EoR data after foreground removal. Hence, the current LOFAR-EoR 21 cm power spectrum limits are not likely to depend on the direction-dependent calibration method. For this particular observation, the RA 18h flanking field seems to produce improved upper limits (~30%) compared to the NCP.

The Upper Edge of the Neptune Desert Is Stable Against Photoevaporation

Transit surveys indicate that there is a deficit of Neptune-sized planets on close-in orbits. If this “Neptune desert” is entirely cleared out by atmospheric mass loss, then planets at its upper edge should only be marginally stable against photoevaporation, exhibiting strong outflow signatures in tracers like the metastable helium triplet. We test this hypothesis by carrying out a 12-night photometric survey of the metastable helium feature with Palomar/WIRC, targeting seven gas-giant planets orbiting K-type host stars. Eight nights of data are analyzed here for the first time along with reanalyses of four previously published data sets. We strongly detect helium absorption signals for WASP-69b, HAT-P-18b, and HAT-P-26b; tentatively detect signals for WASP-52b and NGTS-5b; and do not detect signals for WASP-177b and WASP-80b. We interpret these measured excess absorption signals using grids of Parker wind models to derive mass-loss rates, which are in good agreement with predictions from the hydrodynamical outflow code ATES for all planets except WASP-52b and WASP-80b, where our data suggest that the outflows are much smaller than predicted. Excluding these two planets, the outflows for the rest of the sample are consistent with a mean energy-limited outflow efficiency of . Even when we make the relatively conservative assumption that gas-giant planets experience energy-limited outflows at this efficiency for their entire lives, photoevaporation would still be too inefficient to carve the upper boundary of the Neptune desert. We conclude that this feature of the exoplanet population is a pristine tracer of giant planet formation and migration mechanisms.

762-P: Comparing Dual-Hormone and Single-Hormone Automated Insulin Delivery System on Nocturnal Glucose Management among Pediatric People Living with Type 1 Diabetes : A Pooled Analysis

Background: Only three studies have directly compared the efficacy of dual-hormone (DH) automated insulin delivery (AID) systems and single-hormone (SH) AID on overnight glucose management in pediatric people living with type 1 diabetes (PPWT1D) . Their conclusions differ. Pooling data could lead to stronger conclusions. Methods: Pooled data from 3 open-label, randomized, controlled, crossover studies on comparing DH-AID and SH-AID among PPWT1D (8-17 y/o) . The primary outcome was time in range% (TIR%) overnight (00:00-06:00) based on continuous glucose monitoring. Paired t-test was applied to compare the two groups. Results: Records from 50 PPWT1D [median (Q1-Q3) age: 14.0 years (11.8, 16.0) , mean ± SD HbA1c: 8.2 ± 0.8%] provided 246 nights of data (Table) . TIR% [ (median (IQR) ] for SH-AID and DH-AID was 91.3% (58.3, 100.0) and 94.4% (76.4, 100.0) , respectively (P=0.024) . DH-AID was superior to SH-AID in reducing time in hypo- (<3.9 mmol/L) and hyperglycemia (>13.9 mmol/L) but not glycemic variability. Conclusion: DH-AID has the potential to provide better overnight glucose management than SH-AID in PPWT1D. Disclosure Z.Wu: Other Relationship; Eli Lilly and Company. V.Messier: None. M.Lebbar: None. R.Rabasa-lhoret: Consultant; HLS Therapeutics Inc., Pfizer Inc., Other Relationship; Abbott Diabetes, AstraZeneca, Boehringer Ingelheim International GmbH, Dexcom, Inc., Eli Lilly and Company, Insulet Corporation, Janssen Pharmaceuticals, Inc., Medtronic, Merck & Co., Inc., Novo Nordisk Canada Inc., Sanofi, Vertex Pharmaceuticals Incorporated, Research Support; Canadian Institutes of Health Research, Cystic Fibrosis Canada, Diabetes Canada, Fondation Francophone pour la Recherche en Diabète (FFRD) , JDRF, National Institutes of Health, Société Francophone du Diabète (SFD) , Speaker's Bureau; Canadian Medical & Surgical Knowledge Translation Research Group (CMS) , CPD Network, Tandem Diabetes Care, Inc. Funding Diabetes Canada grant (OG-2-12-3868-RR,OG-2-13-42P, OG-3-14-4500-RR) and Fondation JA De Sève

0352 Compliance to Sleep Recommendations: A Big Data Analysis In Users of a Consumer Sleep Technology

Abstract Introduction The National Sleep Foundation has published sleep time duration (Hirshkowitz et al., 2015) and sleep quality (Ohayon et al., 2017) recommendations across the lifespan based on expert panel input. These recommendations offer sleep guidance to millions of individuals. Many individuals are using commercially available sleep tracking devices to measure their sleep. We analyzed the data of two non-contact radiofrequency sleep measurement devices (SleepScore Max (SleepScore Labs) and S+ (ResMed), both validated against PSG) to determine how well the users of these devices are sleeping. Methods Total Sleep Time (TST), sleep latency (SL) and sleep efficiency (SE) data of 40,892 users between 15 and 98 years old were used in this analysis, covering 5,513,369 nights of data, and averages per user were calculated. In alignment with the aforementioned papers, the data were split in 3 age groups; Young Adults (18-25), Adults (26-64) and Older Adults (>=65), and the criteria as listed were used, classifying the sleep indicators in 3 bins; Appropriate/Recommended, Uncertain/ May be Recommended, and Inappropriate/Not Recommended. Proportion of users meeting the Appropriate/Recommended, Uncertain/May be Appropriate and Inappropriate/Unlikely were calculated for each age group. Results In the Young Adults group most users had an Appropriate SL (SL<= 30 min; 79.7 %), an Appropriate SE (SE>=85%; 53.6 %), but only 30.0% had a Recommended TST (7 to 9 h.). In the Adult group, larger proportions of users met on average the Appropriate measures for SL (SL<= 30 min; 84.8%), SE (SE>= 85%; 58.4%), but only 27.3% slept on average the Recommended hours (TST 7 to 9 h). In the Older Adults group, the average SL and SE was considered Appropriate for most elderly users (SL<30min; 84.3: SE>=85%; 59.6%), but only 28.2% slept the Recommended amount (TST 7 to 8 h). Conclusion 30% or less users slept on average the recommended amount, whereas slightly over half of the users showed the recommended sleep efficiency, and at least 79.7% fell on average asleep within 30 minutes. These results show that sleep improvement campaigns need to focus on extending the sleep duration and sleep hygiene to improve SE. Support (If Any)

Sleeping in an Inclined Position to Reduce Snoring and Improve Sleep: In-home Product Intervention Study.

BackgroundAccurately and unobtrusively testing the effects of snoring and sleep interventions at home has become possible with recent advances in digital measurement technologies.ObjectiveThe aim of this study was to examine the effectiveness of using an adjustable bed base to sleep with the upper body in an inclined position to reduce snoring and improve sleep, measured at home using commercially available trackers.MethodsSelf-reported snorers (N=25) monitored their snoring and sleep nightly and completed questionnaires daily for 8 weeks. They slept flat for the first 4 weeks, then used an adjustable bed base to sleep with the upper body at a 12-degree incline for the next 4 weeks.ResultsOver 1000 nights of data were analyzed. Objective snoring data showed a 7% relative reduction in snoring duration (P=.001) in the inclined position. Objective sleep data showed 4% fewer awakenings (P=.04) and a 5% increase in the proportion of time spent in deep sleep (P=.02) in the inclined position. Consistent with these objective findings, snoring and sleep measured by self-report improved.ConclusionsNew measurement technologies allow intervention studies to be conducted in the comfort of research participants’ own bedrooms. This study showed that sleeping at an incline has potential as a nonobtrusive means of reducing snoring and improving sleep in a nonclinical snoring population.

Multinight Prevalence, Variability, and Diagnostic Misclassification of Obstructive Sleep Apnea.

RationaleRecent studies suggest that obstructive sleep apnea (OSA) severity can vary markedly from night to night, which may have important implications for diagnosis and management.ObjectivesThis study aimed to assess OSA prevalence from multinight in-home recordings and the impact of night-to-night variability in OSA severity on diagnostic classification in a large, global, nonrandomly selected community sample from a consumer database of people that purchased a novel, validated, under-mattress sleep analyzer.MethodsA total of 67,278 individuals aged between 18 and 90 years underwent in-home nightly monitoring over an average of approximately 170 nights per participant between July 2020 and March 2021. OSA was defined as a nightly mean apnea–hypopnea index (AHI) of more than 15 events/h. Outcomes were multinight global prevalence and likelihood of OSA misclassification from a single night’s AHI value.Measurements and Main ResultsMore than 11.6 million nights of data were collected and analyzed. OSA global prevalence was 22.6% (95% confidence interval, 20.9–24.3%). The likelihood of misdiagnosis in people with OSA based on a single night ranged between approximately 20% and 50%. Misdiagnosis error rates decreased with increased monitoring nights (e.g., 1-night F1-score = 0.77 vs. 0.94 for 14 nights) and remained stable after 14 nights of monitoring.ConclusionsMultinight in-home monitoring using novel, noninvasive under-mattress sensor technology indicates a global prevalence of moderate to severe OSA of approximately 20%, and that approximately 20% of people diagnosed with a single-night study may be misclassified. These findings highlight the need to consider night-to-night variation in OSA diagnosis and management.

A Search for L4 Earth Trojan Asteroids Using a Novel Track-before-detect Multiepoch Pipeline

Abstract Earth Trojan asteroids are an important but elusive population that co-orbit with Earth at the L4 and L5 Lagrange points. There is only one known, but a large population is theoretically stable and could provide insight into our solar system’s past and present, as well as planetary defense. In this paper, we present the results of an Earth Trojan survey that uses a novel shift-and-stack detection method on 2 nights of data from the Dark Energy Camera. We find no new Earth Trojan asteroids. We calculate an upper limit on the population that is consistent with previous searches despite much less sky coverage. Additionally, we elaborate on previous upper-limit calculations using current asteroid population statistics and an extensive asteroid simulation to provide the most up-to-date population constraints. We find an L4 Earth Trojan population of for H = 13.93, for H = 16, and for H = 22.

No familiarization or 'first-night effect' evident when monitoring sleep using wrist actigraphy.

Anecdotal reports suggest that the first night of sleep monitoring using a wrist-actigraphy monitor may result in impaired sleep when compared to subsequent nights, due to increased levels of anxiety and awareness of being monitored. This phenomenon has been seen in sleep laboratories with polysomnographic monitoring. However, this is yet to be established for wrist actigraphy monitoring in the research literature. A total of 240 healthy adult participants (177 male, 63 female; age range, 18-35years) had their sleep monitored using wrist actigraphy over a period of five nights of 'normal' sleep (1,200 nights of data). Sleep variables including sleep latency, wake episodes, wake after sleep onset, awakenings per hour, time in bed, total sleep time and sleep efficiency % were evaluated across all nights of sleep. Comparisons were made using repeated measures ANOVAs, mean differences, range of mean differences, intraclass correlation coefficients (ICC) and Cohen's d effect sizes. There were no significant differences between the first night and subsequent nights for any of the measured sleep variables (p<.05) and all differences were associated with trivial effect sizes (d<0.2). ICCs ranged from 0.35 to 0.62 (low to moderate). Despite claims of impaired sleep during the first night of sleep monitoring, our results indicate that a familiarization period may not be necessary when monitoring sleep in healthy participants using wrist actigraphy. However, the response is highly individual and further research is required to assess personality traits and responses to sleep monitoring.

Feasibility and Acceptability of Wearable Sleep Electroencephalogram Device Use in Adolescents: Observational Study.

BackgroundAdolescence is an important life stage for the development of healthy behaviors, which have a long-lasting impact on health across the lifespan. Sleep undergoes significant changes during adolescence and is linked to physical and psychiatric health; however, sleep is rarely assessed in routine health care settings. Wearable sleep electroencephalogram (EEG) devices may represent user-friendly methods for assessing sleep among adolescents, but no studies to date have examined the feasibility and acceptability of sleep EEG wearables in this age group.ObjectiveThe goal of the research was to investigate the feasibility and acceptability of sleep EEG wearable devices among adolescents aged 11 to 17 years.MethodsA total of 104 adolescents aged 11 to 17 years participated in 7 days of at-home sleep recording using a self-administered wearable sleep EEG device (Zmachine Insight+, General Sleep Corporation) as well as a wristworn actigraph. Feasibility was assessed as the number of full nights of successful recording completed by adolescents, and acceptability was measured by the wearable acceptability survey for sleep. Feasibility and acceptability were assessed separately for the sleep EEG device and wristworn actigraph.ResultsA total of 94.2% (98/104) of adolescents successfully recorded at least 1 night of data using the sleep EEG device (mean number of nights 5.42; SD 1.71; median 6, mode 7). A total of 81.6% (84/103) rated the comfort of the device as falling in the comfortable to mildly uncomfortable range while awake. A total of 40.8% (42/103) reported typical sleep while using the device, while 39.8% (41/103) indicated minimal to mild device-related sleep disturbances. A minority (32/104, 30.8%) indicated changes in their sleep position due to device use, and very few (11/103, 10.7%) expressed dissatisfaction with their experience with the device. A similar pattern was observed for the wristworn actigraph device.ConclusionsWearable sleep EEG appears to represent a feasible, acceptable method for sleep assessment among adolescents and may have utility for assessing and treating sleep disturbances at a population level. Future studies with adolescents should evaluate strategies for further improving usability of such devices, assess relationships between sleep EEG–derived metrics and health outcomes, and investigate methods for incorporating data from these devices into emerging digital interventions and applications.Trial RegistrationClinicalTrials.gov NCT03843762; https://clinicaltrials.gov/ct2/show/NCT03843762

Deep learning for automated sleep staging using instantaneous heart rate

Clinical sleep evaluations currently require multimodal data collection and manual review by human experts, making them expensive and unsuitable for longer term studies. Sleep staging using cardiac rhythm is an active area of research because it can be measured much more easily using a wide variety of both medical and consumer-grade devices. In this study, we applied deep learning methods to create an algorithm for automated sleep stage scoring using the instantaneous heart rate (IHR) time series extracted from the electrocardiogram (ECG). We trained and validated an algorithm on over 10,000 nights of data from the Sleep Heart Health Study (SHHS) and Multi-Ethnic Study of Atherosclerosis (MESA). The algorithm has an overall performance of 0.77 accuracy and 0.66 kappa against the reference stages on a held-out portion of the SHHS dataset for classifying every 30 s of sleep into four classes: wake, light sleep, deep sleep, and rapid eye movement (REM). Moreover, we demonstrate that the algorithm generalizes well to an independent dataset of 993 subjects labeled by American Academy of Sleep Medicine (AASM) licensed clinical staff at Massachusetts General Hospital that was not used for training or validation. Finally, we demonstrate that the stages predicted by our algorithm can reproduce previous clinical studies correlating sleep stages with comorbidities such as sleep apnea and hypertension as well as demographics such as age and gender.

1193 Accuracy of a Commercial Wearable in Detecting Sleep Stages Compared to Polysomnography in Adults: Considering Sleep Classification Methods and Effects of Evening Alcohol Consumption

Abstract Introduction Commercial wearable devices have shown the capability of collecting and processing multisensor information (motion, cardiac activity), claiming to be able to measure sleep-wake patterns and differentiate sleep stages. While using these devices, users should be aware of their accuracy, sources of measurement error and contextual factors that may affect their performance. Here, we evaluated the agreement between Fitbit Charge 2™ and PSG in adults, considering effects of two different sleep classification methods and pre-sleep alcohol consumption. Methods Laboratory-based synchronized recordings of device and PSG data were obtained from 14 healthy adults (42.6±9.7y; 6 women), who slept between one and three nights in the lab, for a total of 27 nights of data. On 10 of these nights, participants consumed alcohol (up to 4 standard drinks) in the 2 hours before bedtime. Device performance relative to PSG was evaluated using epoch-by-epoch and Bland-Altman analyses, with device data obtained from a data-management platform, Fitabase, via two methods one that accounts for short wakes (SW, awakenings that last less than 180s) and one that does not (not-SW). Results SW and not-SW methods were similar in scoring (96.76% agreement across epochs), although the SW method had better accuracy for differentiating “light”, “deep”, and REM sleep; but produced more false positives in wake detection. The device (SW-method) classified epochs of wake, “light” (N1+N2), “deep” (N3) and REM sleep with 56%, 77%, 46%, and 62% sensitivity, respectively. Bland-Altman analysis showed that the device significantly underestimated “light” (~19min) and “deep” (~26min) sleep. Alcohol consumption enhanced PSG-device discrepancies, in particular for REM sleep (p=0.01). Conclusion Our results indicate promising accuracy in sleep-wake and sleep stage identification for this device, particularly when accounting for short wakes, as compared to PSG. Alcohol consumption, as well as other potential confounders that could affect measurement accuracy should be further investigated. Support This study was supported by the National Institute on Alcohol Abuse and Alcoholism (NIAAA) grant R21-AA024841 (IMC and MdZ). The content is solely the responsibility of the authors and does not necessarily represent the official views the National Institutes of Health.

Deviations from normal bedtimes are associated with short-term increases in resting heart rate

Despite proper sleep hygiene being critical to our health, guidelines for improving sleep habits often focus on only a single component, namely, sleep duration. Recent works, however, have brought to light the importance of another aspect of sleep: bedtime regularity, given its ties to cognitive and metabolic health outcomes. To further our understanding of this often-neglected component of sleep, the objective of this work was to investigate the association between bedtime regularity and resting heart rate (RHR): an important biomarker for cardiovascular health. Utilizing Fitbit Charge HRs to measure bedtimes, sleep and RHR, 255,736 nights of data were collected from a cohort of 557 college students. We observed that going to bed even 30 minutes later than one’s normal bedtime was associated with a significantly higher RHR throughout sleep (Coeff +0.18; 95% CI: +0.11, +0.26 bpm), persisting into the following day and converging with one’s normal RHR in the early evening. Bedtimes of at least 1 hour earlier were also associated with significantly higher RHRs throughout sleep; however, they converged with one’s normal rate by the end of the sleep session, not extending into the following day. These observations stress the importance of maintaining proper sleep habits, beyond sleep duration, as high variability in bedtimes may be detrimental to one’s cardiovascular health.

Relationships between Post-Concussion Sleep and Symptom Recovery: A Preliminary Study.

Post-concussion sleep disturbances can be debilitating and may influence days to symptom recovery; however, evidence is minimal. The purpose of this study was to explore relationships between days to symptom recovery and aspects of sleep, as measured by actigraphy and subjective sleep questionnaires in a concussed sample. Thirty-one college students were physician-diagnosed with a concussion and asked to complete a daily sleep symptom checklist. Participants (n = 14) were excluded based on lack of compliance/early termination (22.6%), recorded <5 nights of data (12.9%), and protracted recoveries (3.2%). Final concussed sample included 17 college-aged students (varsity student-athletes, n = 5; university students, n = 12). A wrist-worn ActiGraph GT9X Link was provided during initial evaluation (within 72 h post-injury) and worn continuously until symptom recovery (follow-up evaluation; 14.3 ± 5.9 days post-injury). The Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) also were completed at follow-up. Pearson's correlations were conducted to determine relationships between days to symptom recovery and actigraphy sleep outcomes (sleep onset latency, wake after sleep onset (WASOnorm), total sleep time, sleep efficiency (SE), and number of awakenings) across recovery stages (2-3 days post-injury, mid-point, and end). Spearman's rho correlations were used to determine relationships between subjective sleep (PSQI global), sleepiness (ESS total), and sleep cluster symptom severity and days to symptom recovery. At recovery mid-point, individuals who were awake longer throughout the night (24.1 ± 9.0%) and/or were less efficient at sleeping (73.7 ± 9.7%) took longer to recover (WASOnorm: r = 0.58, p = 0.015; SE: r = -0.51, p = 0.035). Poorer post-concussion sleep quality (based on PSQI) was correlated with longer recovery (rs = 0.70, p = 0.001). Post-concussion sleep-wake disturbances at recovery mid-point and overall poorer sleep quality may be associated with longer symptom recovery. Our findings provide preliminary guidance on identifying those who may be at risk for longer recoveries based on poorer sleep post-injury.

Unprecedented Near-infrared Brightness and Variability of Sgr A*

Abstract The electromagnetic counterpart to the Galactic center supermassive black hole, Sgr A*, has been observed in the near-infrared for over 20 yr and is known to be highly variable. We report new Keck Telescope observations showing that Sgr A* reached much brighter flux levels in 2019 than ever measured at near-infrared wavelengths. In the K′ band, Sgr A* reached flux levels of ∼6 mJy, twice the level of the previously observed peak flux from &gt;13,000 measurements over 130 nights with the Very Large Telescope and Keck Telescopes. We also observe a factor of 75 change in flux over a 2 hr time span with no obvious color changes between 1.6 and 2.1 μm. The distribution of flux variations observed this year is also significantly different than the historical distribution. Using the most comprehensive statistical model published, the probability of a single night exhibiting peak flux levels observed this year, given historical Keck observations, is less than 0.3%. The probability of observing flux levels that are similar to all four nights of data in 2019 is less than 0.05%. This increase in brightness and variability may indicate a period of heightened activity from Sgr A* or a change in its accretion state. It may also indicate that the current model is not sufficient to model Sgr A* at high flux levels and should be updated. Potential physical origins of Sgr A*'s unprecedented brightness may be from changes in the accretion flow as a result of the star S0-2's closest passage to the black hole in 2018, or from a delayed reaction to the approach of the dusty object G2 in 2014. Additional multi-wavelength observations will be necessary to both monitor Sgr A* for potential state changes and to constrain the physical processes responsible for its current variability.

The Effect of Structured Exercise on Sleep During the Corresponding Night Among Older Women in an Exercise Program.

This study investigated the acute effect of exercise on sleep outcomes among healthy older women by comparing days with structured exercise versus days without structured exercise during 4 months of exercise training. Participants (n = 51) in this study had wrist-worn actigraphic sleep data available following at least 3 days with structured exercise and 3 days without structured exercise at mid-intervention and at the end of intervention. The exercise intervention was treadmill walking. Multilevel models were used to examine whether structured exercise impacted sleep outcomes during the corresponding night. Overall, 1,362 nights of data were included in the analyses. In unadjusted and adjusted models, bedtimes were significantly earlier on evenings following an acute bout of structured exercise than on evenings without structured exercise. No other sleep parameters differed between exercise and nonexercise days. Understanding the effects of exercise on sleep in this understudied population may help to improve their overall sleep quality.

A Deep Search for Planets in the Inner 15 au around Vega

Abstract We present the results of a deep high-contrast imaging search for planets around Vega. Vega is an ideal target for high-contrast imaging because it is bright, nearby, and young with a face-on two-belt debris disk that may be shaped by unseen planets. We obtained J- and H-band data on Vega with the coronagraphic integral-field spectrograph Project 1640 (P1640) at Palomar Observatory. Two nights of data were obtained in 2016, in poor seeing conditions, and two additional nights in more favorable conditions in 2017. In total, we obtained 5.5 hours of integration time on Vega in moderate to good seeing conditions (&lt;1.″5). We did not detect any low-mass companions in this system. Our data present the most sensitive contrast limits around Vega at very small separations (2–15 au) thus far, allowing us to place new constraints on the companions that may be sculpting the Vega system. In addition to new constraints, as the deepest data obtained with P1640, these observations form the final legacy of the now decommissioned instrument.

Monitoring Telluric Absorption with CAMAL

Ground-based astronomical observations may be limited by telluric water vapor absorption, which is highly variable in time and significantly complicates both spectroscopy and photometry in the near-infrared (NIR). To achieve the sensitivity required to detect Earth-sized exoplanets in the NIR, simultaneous monitoring of precipitable water vapor (PWV) becomes necessary to mitigate the impact of variable telluric lines on radial velocity measurements and transit light curves. To address this issue, we present the Camera for the Automatic Monitoring of Atmospheric Lines (CAMAL), a stand-alone, inexpensive six-inch aperture telescope dedicated to measuring PWV at the Fred Lawrence Whipple Observatory on Mount Hopkins. CAMAL utilizes three narrowband NIR filters to trace the amount of atmospheric water vapor affecting simultaneous observations with the MINiature Exoplanet Radial Velocity Array (MINERVA) and MINERVA-Red telescopes. Here, we present the current design of CAMAL, discuss our data analysis methods, and show results from 11 nights of PWV measurements taken with CAMAL. For seven nights of data we have independent PWV measurements extracted from high-resolution stellar spectra taken with the Tillinghast Reflector Echelle Spectrometer (TRES) also located on Mount Hopkins. We use the TRES spectra to calibrate the CAMAL absolute PWV scale. Comparisons between CAMAL and TRES PWV estimates show excellent agreement, matching to within 1 mm over a 10 mm range in PWV. Analysis of CAMAL’s photometric precision propagates to PWV measurements precise to better than 0.5 mm in dry (PWV < 4 mm) conditions. We also find that CAMAL-derived PWVs are highly correlated with those from a GPS-based water vapor monitor located approximately 90 km away at Kitt Peak National Observatory, with a root mean square PWV difference of 0.8 mm.

The Accuracy, Night-to-Night Variability, and Stability of Frontopolar Sleep Electroencephalography Biomarkers.

To assess the validity of sleep architecture and sleep continuity biomarkers obtained from a portable, multichannel forehead electroencephalography (EEG) recorder. Forty-seven subjects simultaneously underwent polysomnography (PSG) while wearing a multichannel frontopolar EEG recording device (Sleep Profiler). The PSG recordings independently staged by 5 registered polysomnographic technologists were compared for agreement with the autoscored sleep EEG before and after expert review. To assess the night-to-night variability and first night bias, 2 nights of self-applied, in-home EEG recordings obtained from a clinical cohort of 63 patients were used (41% with a diagnosis of insomnia/depression, 35% with insomnia/obstructive sleep apnea, and 17.5% with all three). The between-night stability of abnormal sleep biomarkers was determined by comparing each night's data to normative reference values. The mean overall interscorer agreements between the 5 technologists were 75.9%, and the mean kappa score was 0.70. After visual review, the mean kappa score between the autostaging and five raters was 0.67, and staging agreed with a majority of scorers in at least 80% of the epochs for all stages except stage N1. Sleep spindles, autonomic activation, and stage N3 exhibited the least between-night variability (P < .0001) and strongest between-night stability. Antihypertensive medications were found to have a significant effect on sleep quality biomarkers (P < .02). A strong agreement was observed between the automated sleep staging and human-scored PSG. One night's recording appeared sufficient to characterize abnormal slow wave sleep, sleep spindle activity, and heart rate variability in patients, but a 2-night average improved the assessment of all other sleep biomarkers. Two commentaries on this article appear in this issue on pages 771 and 773.

GENERALIZED DERIVATION OF THE RRV METHOD AND ITS APPLICATION

ABSTRACT Very recently, Heinze &amp; Metchev proposed a novel method for calculating precise distances to the main-belt asteroids using only two nights of data from a single observatory. In this paper, we re-derive the solution but use easily understood spherical astronomy. Our derivation is based on the premise that the geocentric angular velocity of an asteroid changes linearly with time, which is closer to the real situation. Therefore, a possible extra error of rotational reflex velocity, in some cases, is eliminated. A total of 193 frames of CCD images over four nights for 10 asteroids in a conventional stare mode taken with the 1 m telescope at Yunnan Observatory were used to test the improved solution and precise distances were evaluated.