Bout Duration Research Articles

Distinguishing between children referred for assessment of excessive daytime sleepiness using polysomnographic measures.

BackgroundCurrently, diagnosing narcolepsy and idiopathic hypersomnia (IH) in subjectively sleepy children requires an overnight polysomnographic sleep study followed by a daytime multiple sleep latency test (MSLT). We aimed to compare sleep macro-architecture to identify differences between these groups. MethodsAll children referred for a MSLT between May 2010 to December 2023 whose parent consented for their data be used in research were eligible. Each child was age- and sex- matched to a control. Sleep stability was defined as the maintenance of a particular sleep stage before waking or transitioning to another sleep state. As a measure of sleep disturbance, the number and duration of bouts of each sleep stage was recorded. Results28 children with Narcolepsy, 11 with IH and 26 with subjective sleepiness were included. Children with narcolepsy exhibited higher numbers of transitions to wake after sleep onset compared to their controls and to the subjectively sleepy group (p<0.001 for both). The number of REM bouts was greater in the narcolepsy group compared to their control group (p<0.001), the IH group (p<0.05) and the subjectively sleepy group (p<0.05), while the average duration of REM bouts was shorter in the narcolepsy group compared to both the IH group (p<0.05) and subjectively sleepy group (p<0.05). Mean sleep latency on the MSLT was correlated with a number of polysomnographic variables. ConclusionsOur study suggests that specific sleep architecture patterns could potentially serve as diagnostic biomarkers for distinguishing paediatric narcolepsy from those with IH and those with a non-diagnostic MSLT.

Winter torpor patterns of tricolored bats (Perimyotis subflavus) in the southeastern United States

Abstract The Tricolored Bat (Perimyotis subflavus) has suffered significant population declines in much of its geographic range due to white-nose syndrome (WNS). Our aim was to describe the torpor patterns of tricolored bats within the southeastern United States to further our understanding of their winter ecology and potential susceptibility to WNS in currently unimpacted areas based on data from bats in both a WNS-affected hibernaculum and an unaffected hibernaculum. We placed temperature-sensitive radio transmitters on tricolored bats in a site in northwestern South Carolina that was WNS-positive and another site in northwestern Florida that was WNS-negative, and determined torpid and arousal skin temperatures (TSK), torpor bout duration (TBD), and arousal duration (AD) during 3 winters. Mean hibernacula temperature (TH) and vapor pressure deficit (VPDH) in both hibernacula were within the range of optimal Pseudogymnoascus destructans (Pd) growth (TH = 12.7 to 13.6 °C, VPDH = 0.028 to 0.059 kPA). Mean torpid TSK was 15.7 ± 0.1 °C and mean TBD was 4.1 ± 0.2 days across sites. Sex was the best predictor of TBD with males having significantly longer TBD than females. Torpid TSK was positively related to TH and negatively related to VPDH. Because the TSK of a bat was similar to the optimal growth temperatures of Pd, our findings suggest that even though winters in the southeastern United States are more benign than in other parts of the Tricolored Bat range, the warmer temperatures in southern hibernacula may provide optimal conditions for the growth of Pd. Greater understanding of the physiological responses of tricolored bats in hibernacula across their range will provide important data on the potential for WNS morbidity and mortality in unaffected areas and allow for a better distribution of resources for prevention and treatment of WNS.

Impaired Sleep-Dependent Memory Consolidation in Pediatric Narcolepsy Type 1.

Disrupted nighttime sleep (DNS) is common in pediatric Narcolepsy type 1, yet its cognitive impact is unknown. As N2 sleep spindles are necessary for sleep-dependent memory consolidation, we hypothesized that Narcolepsy Type 1 impairs memory consolidation via N2 sleep fragmentation and N2 sleep spindle alterations. We trained 28 pediatric Narcolepsy Type 1 participants and 27 healthy controls (HC) on a spatial declarative memory task before a nocturnal in-lab polysomnogram and then gave them a cued recall test upon awakening in the morning. We extracted wake and sleep stage bout numbers and N2 spindle characteristics from the polysomnogram and conducted mixed model analysis of sleep-dependent memory consolidation to identify group differences. Narcolepsy Type 1 participants had shorter N2 bout durations and associated shorter N2 spindles vs. HC, but other N2 spindle features were similar. Narcolepsy Type 1 participants had worse memory performance post-sleep than HCs after adjusting for age and gender (mean memory consolidation HC: -3.1% ± 18.7, NT1: -15.6 ± 24.8, main effect group x time of testing F=5.3, p=0.03). We did not find significant relationships between sleep-dependent memory consolidation and N2 spindle characteristics. Notably, increased N1% was associated with worse sleep-dependent memory consolidation with results driven by the Narcolepsy Type 1 group. Sleep-dependent memory consolidation is mildly impaired in youth with Narcolepsy Type 1 and findings may be attributed to increases in N1 sleep. Further studies are needed to determine if these findings are generalizable and reversible with sleep-based therapies.

Smartphone Screen Time Characteristics in People With Suicidal Thoughts: Retrospective Observational Data Analysis Study.

Smartphone-based monitoring in natural settings provides opportunities to monitor mental health behaviors, including suicidal thoughts and behaviors. To date, most suicidal thoughts and behaviors research using smartphones has primarily relied on collecting so-called "active" data, requiring participants to engage by completing surveys. Data collected passively from smartphone sensors and logs may offer an objectively measured representation of an individual's behavior, including smartphone screen time. This study aims to present methods for identifying screen-on bouts and deriving screen time characteristics from passively collected smartphone state logs and to estimate daily smartphone screen time in people with suicidal thinking, providing a more reliable alternative to traditional self-report. Participants (N=126; median age 22, IQR 16-33 years) installed the Beiwe app (Harvard University) on their smartphones, which passively collected phone state logs for up to 6 months after discharge from an inpatient psychiatric unit (adolescents) or emergency department visit (adults). We derived daily screen time measures from these logs, including screen-on time, screen-on bout duration, screen-off bout duration, and screen-on bout count. We estimated the mean of these measures across age subgroups (adults and adolescents), phone operating systems (Android and iOS), and monitoring stages after the discharge (first 4 weeks vs subsequent weeks). We evaluated the sensitivity of daily screen time measures to changes in the parameters of the screen-on bout identification method. Additionally, we estimated the impact of a daylight time change on minute-level screen time using function-on-scalar generalized linear mixed-effects regression. The median monitoring period was 169 (IQR 42-169) days. For adolescents and adults, mean daily screen-on time was 254.6 (95% CI 231.4-277.7) and 271.0 (95% CI 252.2-289.8) minutes, mean daily screen-on bout duration was 4.233 (95% CI 3.565-4.902) and 4.998 (95% CI 4.455-5.541) minutes, mean daily screen-off bout duration was 25.90 (95% CI 20.09-31.71) and 26.90 (95% CI 22.18-31.66) minutes, and mean daily screen-on bout count (natural logarithm transformed) was 4.192 (95% CI 4.041-4.343) and 4.090 (95% CI 3.968-4.213), respectively; there were no significant differences between smartphone operating systems (all P values were >.05). The daily measures were not significantly different for the first 4 weeks compared to the fifth week onward (all P values were >.05), except average screen-on bout in adults (P value = .018). Our sensitivity analysis indicated that in the screen-on bout identification method, the cap on an individual screen-on bout duration has a substantial effect on the resulting daily screen time measures. We observed time windows with a statistically significant effect of daylight time change on screen-on time (based on 95% joint confidence intervals bands), plausibly attributable to sleep time adjustments related to clock changes. Passively collected phone logs offer an alternative to self-report measures for studying smartphone screen time characteristics in people with suicidal thinking. Our work demonstrates the feasibility of this approach, opening doors for further research on the associations between daily screen time, mental health, and other factors.

Move less, spend more: the metabolic demands of short walking bouts.

The metabolic cost of steady-state walking is well known; however, across legged animals, most walking bouts are too short to reach steady state. Here, we investigate how bout duration affects the metabolic cost of human walking with varying mechanical power, metabolic intensity and duration. Ten participants walked for 10- to 240-s bouts on a stair climber at 0.20, 0.25 and 0.36 m s-1 and on a treadmill at 1.39 m s-1. Oxygen uptake was time-integrated and divided by bout duration to get bout average uptake (V̇O2(b)). Fitting of oxygen uptake kinetics allowed calculating non-metabolic oxygen exchange during phase-I transient and, hence, non-steady-state metabolic cost (C met(b)) and efficiency. For 240-s bouts, such variables were also calculated at steady state. Across all conditions, shorter bouts had higher V̇O2(b) and C met(b), with proportionally greater non-metabolic oxygen exchange. As the bout duration increased, V̇O2(b), C met(b) and efficiency approached steady-state values. Our findings show that the time-averaged oxygen uptake and metabolic cost are greater for shorter than longer bouts: 30-s bouts consume 20-60% more oxygen than steady-state extrapolations. This is partially explained by the proportionally greater non-metabolic oxygen uptake and leads to lower efficiency for shorter bouts. Inferring metabolic cost from steady state substantially underestimates energy expenditure for short bouts.

Regulation of wakefulness by neurotensin neurons in the lateral hypothalamus

The lateral hypothalamic region (LH) has been identified as a key region for arousal regulation, yet the specific cell types and underlying mechanisms are not fully understood. While neurons expressing orexins (OX) are considered the primary wake-promoting population in the LH, their loss does not reduce daily wake levels, suggesting the presence of additional wake-promoting populations. In this regard, we recently discovered that a non-OX cell group in the LH, marked by the expression of neurotensin (Nts), could powerfully drive wakefulness. Activation of these NtsLH neurons elicits rapid arousal from non-rapid eye movement (NREM) sleep and produces uninterrupted wakefulness for several hours in mice. However, it remains unknown if these neurons are necessary for spontaneous wakefulness and what their precise role is in the initiation and maintenance of this state. To address these questions, we first examined the activity dynamics of the NtsLH population across sleep-wake behavior using fiber photometry. We find that NtsLH neurons are more active during wakefulness, and their activity increases concurrently with, but does not precede, wake-onset. We then selectively destroyed the NtsLH neurons using a diphtheria-toxin-based conditional ablation method, which significantly reduced wake amounts and mean duration of wake bouts and increased the EEG delta power during wakefulness. These findings demonstrate a crucial role for NtsLH neurons in maintaining normal arousal levels, and their loss may be associated with chronic sleepiness in mice.

Effect of temporal water restrictions on drinking behavior and time budget in lactating dairy cows according to their position in the social hierarchy within the herd

On dairy farms, milking practices can temporarily restrict cows from accessing drinking water. This study examined how different types of temporary water restriction, similar to those commonly encountered on farms, may affect the individual behavior and physiological dehydration status of cows and whether these effects could differ according to the cow's position in the social hierarchy of the group. Four treatments were applied (CTRL = free access to the drinker and feed fence, HL = 2 h of headlock at the feed fence after morning and evening milking, D2H = free access to the feed fence and no access to water for 2 h after milking and D4H = free access to the feed fence and no access to water for 4 h after milking) to 4 groups of 10 lactating dairy cows using a 4 × 4 Latin square design. Each treatment period lasted 1 week. The cows were housed within a free-stall barn, and each group was in a pen equipped with 1 electronic drinker, 10 individual feeders, and 2 cameras. Cow social dominance hierarchies were characterized using normalized David's scores, which were calculated from video-detected replacements at each pen's drinker. During the last 4 d of each treatment period, drinking behavior was measured using interconnected drinkers, and eating, idle, and lying times were measured using accelerometers. On d 6 of each treatment period, during the morning and evening milkings, blood and then milk samples were collected to analyze bioindicators of dehydration and milk composition, respectively. The daily water intake of cows was unaffected by either social dominance or treatment type. Drinking rate and drinking bout frequency were higher during the HL, D2H, and D4H treatments than during the CTRL treatment, and drinking time was lower during the D4H treatment than during the CTRL treatment. Hourly lying time decreased at the end of the water restriction periods, i.e., at 1000 h in HL, at 1100 h in D2H, and at 1200 and 1300 h in D4H, which was not observed in CTRL, which could be interpreted as a sign of cow discomfort. For blood collected before the morning milking, hematocrit levels were lower in the D4H treatment than in the HL treatment. For blood collected before the evening milking, creatinine concentrations were lower in the D4H treatment than in the D2H treatment, with a greater difference seen for dominant cows than for subordinate cows. For both milkings, milk freezing point was higher in the HL, D2H, and D4H treatments than in the CTRL treatment, indicating dilution. In contrast to the other social categories, subordinate cows made more daily visits to the drinker during the D4H treatment than during the CTRL treatment but displayed no differences in drinking bout duration or the duration of drinking interruptions within bouts in the D2H treatment compared with the CTRL treatment. Overall, cows were able to maintain their water intake despite the temporary water restrictions when they had access to the number of drinkers recommended by animal welfare guidelines. That said, their idle and lying time appeared to be disturbed.

Detection of sedentary time and bouts using consumer-grade wrist-worn devices: a hidden semi-Markov model

BackgroundWrist-worn data from commercially available devices has potential to characterize sedentary time for research and for clinical and public health applications. We propose a model that utilizes heart rate in addition to step count data to estimate the proportion of time spent being sedentary and the usual length of sedentary bouts.MethodsWe developed and trained two Hidden semi-Markov models, STEPHEN (STEP and Heart ENcoder) and STEPCODE (STEP enCODEr; a steps-only based model) using consumer-grade Fitbit device data from participants under free living conditions, and validated model performance using two external datasets. We used the median absolute percentage error (MDAPE) to measure the accuracy of the proposed models against research-grade activPAL device data as the referent. Bland-Altman plots summarized the individual-level agreement with activPAL.ResultsIn OPTIMISE cohort, STEPHEN’s estimates of the proportion of time spent sedentary had significantly (p < 0.001) better accuracy (MDAPE [IQR] = 0.15 [0.06–0.25] vs. 0.23 [0.13–0.53)]) and agreement (Bias Mean [SD]=-0.03[0.11] vs. 0.14 [0.11]) than the proprietary software, estimated the usual sedentary bout duration more accurately (MDAPE[IQR] = 0.11[0.06–0.26] vs. 0.42[0.32–0.48]), and had better agreement (Bias Mean [SD] = 3.91[5.67] minutes vs. -11.93[5.07] minutes). With the ALLO-Active dataset, STEPHEN and STEPCODE did not improve the estimation of proportion of time spent sedentary, but STEPHEN estimated usual sedentary bout duration more accurately than the proprietary software (MDAPE[IQR] = 0.19[0.03–0.25] vs. 0.36[0.15–0.48]) and had smaller bias (Bias Mean[SD] = 0.70[8.89] minutes vs. -11.35[9.17] minutes).ConclusionsSTEPHEN can characterize the proportion of time spent being sedentary and usual sedentary bout length. The methodology is available as an open access R package available from https://github.com/limfuxing/stephen/. The package includes trained models, but users have the flexibility to train their own models.

Do personality profiles contribute to patterns of physical activity and sedentary behavior in adulthood? A prospective cohort study

BackgroundDespite the observed associations of personality traits with levels of moderate-to-vigorous physical activity (MVPA) and sedentary behavior (SB), studies exploring whether the personality profiles differ in terms of the pattern of accumulation of physical behavior are lacking. The aim of this study was to identify adults’ personality profiles and to characterize and investigate how these profiles differ in physical behavior.MethodsThe study utilized the longitudinal data of the participants of the Jyväskylä Longitudinal Study of Personality and Social Development (n = 141–307). Information on the five-factor model of personality, including the traits of neuroticism, extraversion, conscientiousness, openness, and agreeableness, was collected at ages 33, 42, 50, and 61 years, and used to create latent personality profiles. Physical behavior, operationalized as the amount and accumulation of MVPA and SB bouts, was captured using a triaxial accelerometer worn during waking hours at age 61 years. The differences in the behavior between the personality profiles were analyzed using the Kruskal-Wallis test.ResultsFive personality profiles were identified: resilient (20.2%), brittle (14.0%), overcontrolled (9.8%), undercontrolled (15.3%), and ordinary (40.7%). Although there were no statistically significant differences between the personality profiles in the time spent in MVPA relative to SB (MVPA per hour of daily SB), individuals with resilient (low in neuroticism and high in other traits) and ordinary (average in each trait) profiles had MVPA-to-SB ratios of 0.12 (7 min) and those with a brittle (high in neuroticism and low in extraversion) profile had a ratio of 0.09 (5.5 min). The individuals in the resilient group exhibited a longer usual MVPA bout duration than those in the overcontrolled (low in extraversion, openness, and agreeableness) (8 min vs. 2 min) and undercontrolled (high in openness and low in conscientiousness) groups (8 min vs. 3 min). They also exhibited a longer usual SB bout duration than those in the ordinary group (29 min vs. 23 min).ConclusionsThe resilient group displayed the most prolonged MVPA and SB bout patterns. The results suggest that personality characteristics may contribute to how MVPA and SB are accumulated.

Adis Summary of Research: Number, duration, and distribution of wake bouts in patients with insomnia disorder: effect of daridorexant and zolpidem

Adis Summary of Research: Number, duration, and distribution of wake bouts in patients with insomnia disorder: effect of daridorexant and zolpidem

Intra-species quantification reveals differences in activity and sleep levels in the yellow fever mosquito, Aedes aegypti.

Aedes aegypti is an important mosquito vector of human disease with a wide distribution across the globe. Climatic conditions and ecological pressure drive differences in the biology of several populations of this mosquito species, including blood-feeding behaviour and vector competence. However, no study has compared activity and/or sleep among different populations/lineages of Ae. aegypti. Having recently established sleep-like states in three mosquito species with observable differences in timing and amount of sleep among species, we investigated differences in activity and sleep levels among 17 Ae. aegypti lines drawn from both its native range in Africa and its invasive range across the global tropics. Activity monitoring indicates that all the lines show consistent diurnal activity, but significant differences in activity level, sleep amount, number of sleep bouts and bout duration were observed among the lines. The variation in day activity was associated with differences in host preference and ancestry for the lineages collected in Africa. This study provides evidence that the diurnal sleep and activity profiles for Ae. aegypti are consistent, but there are significant population differences for Ae. aegypti sleep and activity levels and interactions with host species may significantly impact mosquito activity.

Hunger signalling in the olfactory bulb primes exploration, food-seeking and peripheral metabolism

ObjectiveAlthough the metabolic state of an organism affects olfactory function, the precise mechanisms and their impact on behavior and metabolism remain unknown. Here, we assess whether ghrelin receptors (GHSRs) in the olfactory bulb (OB) increase olfactory function and influence foraging behaviors and metabolism. MethodsWe performed a detailed behavioural and metabolic analysis in mice lacking GHSRs in the OB (OBGHSR deletion). We also analsyed OB scRNA-seq and spatial transcriptomic datasets to assess GHSR+ cells in the main and accessory olfactory bulbs, as well as the anterior olfactory nucleus. ResultsOBGHSR deletion affected olfactory discrimination and habituation to both food and non-food odors. Anxiety-like and depression-like behaviors were significantly greater after OBGHSR deletion, whereas exploratory behavior was reduced, with the greatest effect under fasted conditions. OBGHSR deletion impacted feeding behavior as evidenced by altered bout number and duration, as well as buried food-seeking. OBGHSR deletion increased body weight and fat mass, spared fat utilisation on a chow diet and impaired glucose metabolism indicating metabolic dysfunction. Cross referenced analysis of OB scRNA-seq and spatial transcriptomic datasets revealed GHSR+ glutamate neurons in the main and accessory olfactory bulbs, as well as the anterior olfactory nucleus. Ablation of glutamate neurons in the OB reduced ghrelin-induced food finding and phenocopied results seen after OBGHSR deletion. ConclusionsOBGHSRs help to maintain olfactory function, particularly during hunger, and facilitate behavioral adaptations that optimise food-seeking in anxiogenic environments, priming metabolic pathways in preparation for food consumption.

Tracking dustbathing behavior of cage-free laying hens with machine vision technologies

Dustbathing (DB) is a functionally important maintenance behavior in birds that clean plumage, realigns feather structures, removes feather lipids, which helps to remove parasites and prevents feathers from becoming too oily. Among different natural behaviors birds perform in cage-free (CF) housing, DB is one of the important behavior related to bird welfare. Earlier studies have identified DB behavior using manual method such as counting number of DB bouts, and duration of DB bouts from video recordings. The manual detection of DB behavior is time-consuming, sometimes prone to errors, and have limitations. Therefore, an automated precision monitoring method is needed to detect DB behavior in laying hens from an early age in CF housing environment. The objectives of this study were to (1) develop and test a deep learning model for detecting DB behavior and find out the optimal model; and (2) assess the performance of the optimal model in detecting DB behavior at different growing phases. In this study, deep learning models, i.e., YOLOv7-DB, YOLOv7x-DB, YOLOv8s-DB and YOLOv8x-DB, networks, were developed, trained, and compared in tracking DB behavior in 4 CF rooms each with 200 hens (W-36 Hy-Line). Results indicate that the YOLOv8x-DB model outperform all other models on detecting DB behavior with a precision of 93.4%, recall of 91.20%, and mean average precision (mAP@0.50) of 93.70%. All models performed with over 90% detection precision; however, model performance was affected by equipment like drinking lines, perches, and feeders. Based on the optimal model (YOLOv8x-DB), DB detection precision was highest during grower phase (precision of 96.80%, recall of 97.10%, mAP@0.50 of 98.60%, and mAP@0.50-0.95 of 79.10% followed by prelay, layers, developer, and peaking phases. This study provides a reference for poultry and egg producers that DB behavior can be detected automatically with precision of at least 89% or more using optimal model at any growing phase of laying hens.

Electromyography of Sedentary Behavior: Identifying Potential for Cardiometabolic Risk Reduction.

Muscle activation during interruptions to prolonged sedentary time is a hypothesized mechanism underlying observed cardiometabolic benefits. We examined associations of quadriceps and hamstring muscle activity patterns with cardiometabolic risk markers and how these patterns varied between different sitting-interruption countermeasures. Electromyographic (EMG) data (shorts) were gathered for 1 to 2 days from healthy adults in a free-living study (n = 172, age 40.9 ± 12.9, BMI 23.6 ± 1.3) and a laboratory-based study (n = 12, age 47.0 ± 7.7, BMI 30.0 ± 4.7). Patterns examined were average EMG (aEMG ;%EMGMVC); EMG activity duration (% above signal baseline 3 μV); and usual (weighted medians) EMG activity bout amplitude (%EMGMVC) and duration (s). In the free-living study, these were regressed against risk markers (waist; fat percentage; fasting plasma glucose [FPG];total cholesterol; HDL;LDL; triglycerides); in the laboratory study, EMG patterns for the muscle groups were compared between sitting and the active countermeasures. In the free-living study, lower extremity muscles displayed minimal overall activity, with hamstrings and quadriceps using only 2.6% and 2.0% of their capacity (%EMGMVC), respectively, and being active for 30% and 25% of the time. Higher hamstring aEMG and EMG activity duration were beneficially associated with waist, HDL and fat percentage (duration only) and a longer quadriceps usual EMG activity bout duration was beneficially associated with FPG. In the laboratory study, compared with prolonged sitting, active seated or upright active-interruption countermeasures modified these EMG patterns; brief (6 min) walking and simple resistance activities (SRA) were more beneficial than was a bout of standing (30 min) with the SRAs being the only intervention that matched daily aEMG levels. Upright and physically active interruptions to sitting appear to be required to increase the typically low muscle engagement observed in free-living contexts, promoting muscle activity patterns that may help ameliorate cardiometabolic risk.

Sex differences in mobility recovery after hip fracture: a time series analysis.

Sex differences are commonly reported for hip fracture incidence rates and recovery. Current knowledge about mobility recovery after hip fracture involves clinical assessments of physical capacity or patient-reported outcomes. Information on mobility performance during daily life is missing but relevant to evaluate patients' recovery. Hence, it remains unclear whether sex differences exist in the longitudinal progression of mobility performance in hip fracture patients. To investigate this, we pooled data from four studies in Germany and Norway. In all studies, real-world mobility was assessed continuously over 1 to 7 days using a sensor fixed to the unaffected frontal thigh. All studies assessed mobility at different time points that were allocated to three distinct phases: Acute and post-acute phase (week 1-6), extended recovery (7-26), and long-term recovery (27-52). Sex-specific continuous trajectories of the median (50th percentile) as well as the 1st (25th percentile) and 3rd quartile (75th percentile) were estimated using quantile regression models with splines for daily walking and standing duration; number of sit-to-stand-to-walk transfers and walking bouts; mean walking bout duration; maximum number of steps per walking bout. There were 5,900 valid observation days from n = 717 participants (mean age = 83.4 years, SD 6.1). The majority was female (75.3%), with similar sex distribution across all studies. Demographics of both sexes were comparable, but a higher percentage of women was living alone (69.0% compared to 40.9% in men) and had experienced an indoor fall leading to the fracture (74.3% compared to 67.4% in men). There were clear sex differences in mobility recovery. Women improved their mobility faster than men, but men showed larger increases later in the year after surgery. At the end of the first year, both sexes reached comparable levels in almost all mobility parameters. We identified varying aspects of mobility recovery between men and women, i.e., timely development of mobility recovery shows different patterns. Our findings support the consideration of sex differences in planning and implementing rehabilitation measures for hip fracture patients and highlight the need to provide adapted support at different time points. The underlying mechanisms of these sex differences need further investigation.

Cubicle design and dairy cow rising and lying down behaviours in free-stalls with insufficient lunge space

Cubicle partitions divide the resting area of free-stalls into individual lying places for cows, thereby facilitating the maintenance of good hygiene and reducing competition by separating animals. The forward lunge space in lying cubicles is often insufficient for a natural head lunge movement during rising. Cubicles with open frame partitions and a flexible neck strap aim to alleviate this welfare issue. The open partition frame facilitates lateral space sharing (using space of neighbouring cubicles for the head lunge movement) and the flexible neck strap is presumably less painful upon collision. In an observational study, we investigated the lying behaviour of free-stall housed dairy cows in this ’permissive’ cubicle type with open frame partitions and a flexible neck strap positioned relatively high above the lying surface compared to ’restrictive’ cubicles with partitions with more bar work in the lateral lunge space and a lower-positioned rigid neck rail. The study was conducted on commercial Swiss dairy farms with exclusively wall-facing lying cubicles of either the permissive (four farms) or restrictive (six farms) type. The forward lunge space on these farms ranged from 55 to 70 cm, which we considered insufficient for adult cows to lunge their heads forward. On each farm, 18–20 lactating dairy cows were selected. In total, 188 animals were used in the statistical analysis. Over 1.5 days, rising and lying down movements were videotaped, and the prevalence of atypical behaviours during these movements was recorded. In addition, we determined the daily lying duration, the lying frequency, and the mean lying bout duration using accelerometers mounted on the left hind leg. The data was analysed in relation to the cubicle type (permissive or restrictive). In the permissive cubicle type, staggered head lunge movements during rising and displays of hesitance before lying down were less prevalent. The lying frequency was higher, and daily lying duration was longer in the permissive cubicle type, although these estimates should be interpreted with caution due to the short data collection period. The results of this study suggest that the permissive cubicle with open partitions and a high-positioned flexible neck strap may improve conditions for dairy cows to rise and lie down. A permissive cubicle design may therefore improve cow welfare in free-stalls with insufficient forward lunge space, where increasing lunge space is not feasible.

Movement- and Posture-based Measures of Sedentary Patterns and Associations with Metabolic Syndrome in Hispanic/Latino and non-Hispanic Adults.

Sedentary behavior has been identified as a significant risk factor for Metabolic Syndrome (MetS). However, it is unclear if the sedentary pattern measurement approach (posture vs. movement) impacts observed associations or if associations differ for Hispanic/Latino communities, who have higher risk of MetS. Participants from the Community of Mine (CoM) study (N = 602) wore hip-based accelerometers for 14days and completed MetS-associated biomarker assessment (triglycerides, blood pressure, fasting glucose, HDL cholesterol, waist circumference). Sedentary patterns were classified using both cutpoints (movement-based) and the Convolutional Neural Network Hip Accelerometer Posture (CHAP) algorithm (posture-based). We used logistic regression to estimate associations between MetS with sedentary patterns overall and stratified by Hispanic/Latino ethnicity. CHAP and cutpoint sedentary patterns were consistently associated with MetS. When controlling for total sedentary time and moderate to vigorous physical activity, only CHAP-measured median sedentary bout duration (OR = 1.15, CI: 1.04, 1.28) was significant. In stratified analysis, CHAP-measured median bout duration and time spent in sedentary bouts ≥ 30min were each associated with increased odds of MetS, but the respective associations were stronger for Hispanic/Latino ethnicity (OR = 1.71 and 1.48; CI = 1.28-2.31 and 1.12-1.98) than for non-Hispanic/Latino ethnicity (OR = 1.43 and 1.40; CI = 1.10-1.87 and 1.06-1.87). The way sedentary patterns are measured can impact the strength and precision of associations with MetS. These differences may be larger in Hispanic/Latino ethnic groups and warrants further research to inform sedentary behavioral interventions in these populations.

Nursing behavior of wild polar bears in the Canadian High Arctic

During 17 spring and summer field seasons between 1973 and 1999, we documented 220 bouts of nursing by dependent polar bear ( Ursus maritimus Phipps, 1774) cubs at Radstock Bay, Nunavut, Canada. The overall mean duration of nursing bouts for cubs-of-the-year (COY) and yearlings (YRLG) litters was 7.1 min (standard deviation (SD) = 3.3, range = 1–23). Mean nursing bout durations of one- and two-cub litters of COY and YRLG in spring and summer seasons ranged from 6.09 to 7.78 min and from 5.00 to 9.18 min, respectively. The overall mean duration of inter-nursing intervals for COY and YRLG litters was 5.7 h (SD = 4.9, range = 0.0–35.0). The mean inter-nursing interval for one-cub litters was 6.4 h (SD = 4.6, range = 0.0–20.2) and for two-cub litters was 5.1 h (SD = 5.1, range = 0.0–35.0). We found no evidence for effects of season or cub age class on nursing behavior. We found weak evidence that two-cub litters nurse slightly longer than one-cub litters, potentially reflecting reduced nursing efficiency due to sibling rivalry. There was neither evidence for diel patterns in nursing behavior nor a detectable relationship between the cessation of nursing and the onset of hunting or sleeping by the adult female.

Daily physical activity in older adults across levels of care: the HUNT Trondheim 70 + study

BackgroundPhysical activity (PA) is imperative for healthy ageing and is a modifiable lifestyle factor. Accurate, clinically meaningful estimates of daily PA among older adults can inform targeted interventions to maintain function and independence. This study describes daily PA in older adults across levels of care as a first step contributing to the limited evidence on potential associations between PA and the use of care services.MethodsThis study used data from the Trondheim 70 + cohort in the population-based Norwegian HUNT Study. In total, 1042 participants aged 70 years or older with valid activity data were included. PA was assessed using two accelerometers over 7 consecutive days and was classified into PA (walking, standing, running, and cycling) and sedentary behavior (sitting and lying). Data on received care services were retrieved from municipal registers and participants were classified into four levels of care: 1) independently living (81.9%), 2) independently living with low-level home care services (6.5%), 3) recipients of home care services (6.0%), and 4) nursing home residents (5.7%). Time spent in the activity types and duration of bouts are presented across levels of care.ResultsParticipants mean age was 77.5 years (range: 70.1–105.4, 55% female) and PA was lower with higher age. Across levels of care, significant group differences were found in the total time spent in PA, particularly in walking and standing. Daily PA, duration of active bouts, and number of daily walking bouts were lower for participants receiving higher levels of care. Standing was the dominant type of PA and walking appeared predominantly in short bouts at all care levels.ConclusionsThis is the first population-based study using device-measured PA to describe daily PA across levels of care. The results showed that low-intensity activities constitute the primary component of everyday PA, advocating for placing greater emphasis on the significant role these activities play in maintaining daily PA at older age. Furthermore, the study demonstrated that activity types and bout durations are related to the ability to live independently among older adults. Overall, these findings can contribute to better target interventions to maintain function and independence in older adults.

Sleep and circadian rhythm activity alterations during adolescence in a mouse model of neonatal fentanyl withdrawal syndrome.

Fentanyl, a highly potent synthetic opioid, is a major contributor to the ongoing opioid epidemic. During adulthood, fentanyl is known to induce pronounced sleep and circadian disturbances during use and withdrawal. Children exposed to opioids in utero are likely to develop neonatal opioid withdrawal syndrome, and display sleep disturbances after birth. However, it is currently unknown how neonatal opioid withdrawal from fentanyl impacts sleep and circadian rhythms in mice later in life. To model neonatal opioid withdrawal syndrome, mice were treated with fentanyl from postnatal days 1 through 14, analogous to the third trimester of human gestation. After weaning, fentanyl and saline treated mice underwent non-invasive sleep and circadian rhythm monitoring during adolescence postnatal days 23 through 30. Neonatal fentanyl exposure led to reduced duration of wake and a decrease in the number of bouts of non-rapid eye movement sleep. Further, neonatally exposed mice displayed an increase in the average duration of rapid eye movement sleep bouts, reflecting an overall increase in the percent time spent in rapid eye movement sleep across days. Neonatal fentanyl exposure leads to altered sleep-wake states during adolescence in mice.