Time Of Day Research Articles

It's About Timing: Contrasting the Metabolic Effects of Early vs. Late Time-Restricted Eating in Humans.

Time-restricted eating (TRE), a form of intermittent fasting, restricts feeding time across the day, imposing a daily 'eating window'. The time of day when the eating window occurs could result in differential metabolic effects. Here, we describe recent intervention studies in humans assessing the metabolic consequences of an early- (i.e., eating window starting in the early morning) vs. late (i.e., eating window starting after midday)-TRE protocol. Well-controlled studies indicate that both TRE protocols effectively reduce body weight and improve altered glucose metabolism, lipid profile, inflammation, or blood pressure levels. An early-TRE (e-TRE) might have a further positive impact on improving blood glucose, insulin levels, and insulin resistance. However, the studies directly assessing the metabolic consequences of an early- vs. late-TRE have shown dissimilar findings, and more well-controlled clinical trials are needed on the metabolic benefits of these two types of TRE. Evidence suggests that an e-TRE might have enhanced metabolic results, particularly regarding glucose homeostasis. More long-term studies, including larger sample sizes, are needed to assess the metabolic, circadian, and adherence benefits, together with socio-cultural acceptance of both TRE approaches.

Measurement and Analysis of 4G/5G Mobile Signal Coverage in a Heavy Industry Environment

In the evolving landscape of Industry 4.0, the integration of advanced wireless technologies into manufacturing processes holds the promise of unprecedented connectivity and efficiency. In particular, the data transmission in a heavy industry environment needs stable connectivity with mobile operators. This paper deals with the performance study of 4G and 5G mobile signal coverage within a complex factory environment. For this purpose, a cost-effective and portable measurement setup was realized and used to provide long-term measurement campaigns monitoring and recording several key parameter indicators (KPIs) in 4G/5G downlink and upload. To support the reproducibility of the provided study and other research activities, the measured dataset is publicly available for download. Among others findings, the obtained results show how the performance of 4G/5G is influenced by a heavy industry environment and of the time of day on the network load.

Circadian Rhythms in NLRP3 Inflammasome Regulation: Possible Implications for the Nighttime Risk of Gout Flares

Gout flares more frequently start late at night or in the early morning compared to during the day. The reasons for this are unknown. Activation of the NLRP3 inflammasome in monocytes/macrophages is central to initiation of gout flares. Here, we review the mechanisms by which circadian clocks control the NLRP3 inflammasome and the implications of this for the nighttime pattern of gout flares. Several hormones involved in inflammation regulation, e.g., glucocorticoids, melatonin and melanocortins, are under circadian control, with both circulating hormone levels as well as the expression of their receptors on target tissues showing time-of day differences. In addition, the NLRP3 inflammasome is also under the control of the macrophage circadian clock, leading to time-of-day differences in expression of NLRP3 inflammasome components and susceptibility to inflammasome-activating stimuli. MSU crystal exposure leads to altered expression of circadian clock components in macrophages, leading to time-of-day-specific loss of repression of NLRP3 inflammasome activity. Taken together, there is clear evidence that circadian clocks regulate the NLRP3 inflammasome and that this regulation may be compromised by MSU crystal exposure in gout. Circadian control of the inflammasome may be one of the factors contributing to nighttime susceptibility to gout flares.

Effect of Human Activity and Presence on the Behavior of Long-Tailed Macaques (Macaca fascicularis) in an Urban Tourism Site in Kuala Selangor, Malaysia

The increasing overlap of resources between human and long-tailed macaque (Macaca fascicularis) (LTM) populations have escalated human–primate conflict. In Malaysia, LTMs are labeled as a ‘pest’ species due to the macaques’ opportunistic nature. This study investigates the activity budget of LTMs in an urban tourism site and how human activities influence it. Observational data were collected from LTMs daily for a period of four months. The observed behaviors were compared across differing levels of human interaction, between different times of day, and between high, medium, and low human traffic zones. LTMs exhibited varying ecological behavior patterns when observed across zones of differing human traffic, e.g., higher inactivity when human presence is high. More concerning is the impact on these animals’ welfare and group dynamics as the increase in interactions with humans takes place; we noted increased inactivity and reduced intra-group interaction. This study highlights the connection that LTMs make between human activity and sources of anthropogenic food. Only through understanding LTM interaction can the cause for human–primate conflict be better understood, and thus, more sustainable mitigation strategies can be generated.

Streamflow prediction using support vector regression machine learning model for Tehri Dam

Accurate and reliable streamflow prediction is critical for optimising water resource management, reservoir flood operations, watershed management, and urban water management. Many researchers have published on streamflow prediction using techniques like Rainfall-Runoff modelling, Time series Models, Data-driven models, Artificial intelligence, etc. Still, there needs to be generalised method practise in the real world. The resolution of this issue lies in selecting different methods for a particular study area. This paper uses the Support vector regression machine learning model to predict the streamflow for the Tehri Dam, Uttarakhand, India, at the Daily and Ten Daily time steps. Two cases are considered in predicting daily and ten daily time steps. The first case includes four input variables: Discharge, Rainfall, Temperature, and Snow cover area. The second case comprises only three input variables: Rainfall, Temperature, and Snow cover area. Radial Kernel is used to overcome the space complexity in the datasets. The K-fold cross-validation is suitable for prediction as it averages the prediction error rate after evaluating the SVR model’s performance on various subsets of the training data. The streamflow data for daily and ten daily time steps have been collected from 2006 to 2020. The calibration period is from 2006 to 2016, and the validation period is from 2017 to 2020. Nash Sutcliffe Efficiency (NSE) and Coefficient of determination (R2) are used as the accuracy indicator in this manuscript. The lag has been observed in the daily prediction time series when three input variables are considered. For other scenarios, the respective model shows excellent results at both the temporal scale and the parametres, which play a vital role in prediction. The study also enhances the effect on the potential use of input parametres in the machine learning model.

Effect of Daytime versus Nighttime on Prehospital Care and Outcomes after Severe Traumatic Brain Injury

Background/Objectives: Severe traumatic brain injury (TBI) is a frequent cause of morbidity and mortality worldwide. In the Netherlands, suspected TBI is a criterion for the dispatch of the physician-staffed helicopter emergency medical services (HEMS) which are operational 24 h per day. It is unknown if patient outcome is influenced by the time of day during which the incident occurs. Therefore, we investigated the association between the time of day of the prehospital treatment of severe TBI and 30-day mortality. Methods: A retrospective analysis of prospectively collected data from the BRAIN-PROTECT study was performed. Patients with severe TBI treated by one of the four Dutch helicopter emergency medical services were included and followed up to one year. The association between prehospital treatment during day- versus nighttime, according to the universal daylight period, and 30-day mortality was analyzed with multivariable logistic regression. A planned subgroup analysis was performed in patients with TBI with or without any other injury. Results: A total of 1794 patients were included in the analysis, of which 1142 (63.7%) were categorized as daytime and 652 (36.3%) as nighttime. Univariable analysis showed a lower 30-day mortality in patients with severe TBI treated during nighttime (OR 0.74, 95% CI 0.60–0.91, p = 0.004); this association was no longer present in the multivariable model (OR 0.82, 95% CI 0.59–1.16, p = 0.262). In a subgroup analysis, no association was found between mortality rates and the time of prehospital treatment in patients with combined injuries (TBI and any other injury). Patients with isolated TBI had a lower mortality rate when treated during nighttime than when treated during daytime (OR 0.51, 95% CI 0.34–0.76, p = 0.001). Within the whole cohort, daytime versus nighttime treatments were not associated with differences in functional outcome defined by the Glasgow Outcome Scale. Conclusions: In the overall study population, no difference was found in 30-day mortality between patients with severe TBI treated during day or night in the multivariable model. Patients with isolated severe TBI had lower mortality rates at 30 days when treated at nighttime.

Intensive management from diagnosis improves HbA1c at 12 months postdiagnosis: results from a prospective cohort study in children with newly diagnosed type 1 diabetes

aims: To examine the impact of intensive management of type 1 diabetes (T1D) from diagnosis on HbA1c 12 months from diagnosis. methods: HbA1c measured 12 months after diagnosis for 70 consecutively newly diagnosed children with T1D following implementation of an intensive management protocol was compared with 70 children consecutively diagnosed immediately pre-implementation. Intensive management involved carbohydrate counting and flexible insulin dosing from first meal with subcutaneous insulin, targeted blood glucose levels from 4–8mmol/L irrespective of time of day, avoidance of twice daily insulin regimen and promotion of continuous glucose monitoring (CGM). HbA1c, diabetes technology use and insulin regimen at 12 months post-diagnosis were compared. results: The post-intensive management implementation cohort had an improved mean HbA1c of 58.2±15.3mmol/mol vs 63.7±10.7mmol/mol at 12 months (p=0.014). The proportion of young people with diabetes meeting a target HbA1c of <53mmol/mol at 12 months improved from 11% to 40% (p=<0.001). There was a reduction of twice daily insulin regimen from 66% to 11% (p=<0.001), and increased CGM use from 57% to 76% (p=0.02). conclusion: Intensive management when implemented with consistent messaging from the multi-disciplinary team resulted in clinic-wide improvements in HbA1c and the proportion meeting HbA1c targets.

Quantifying minimum survey effort to reliably detect Amazonian manatees using an unoccupied aerial vehicle (UAV) at an ex situ soft-release site

Detection of many threatened aquatic mammals, such as manatees (Trichechus spp.), using traditional visual observation methods is associated with high uncertainty due to their low surfacing times, cryptic behaviors, and the environmental heterogeneity of their habitats. Rapid advancements in technology provide an opportunity to address these challenges. In this study, we aimed to quantify survey effort of unoccupied aerial vehicles (UAVs) for detecting the Vulnerable Amazonian manatee (T. inunguis). Using a closed population of manatees that is being rehabilitated within a lake at the Rainforest Awareness, Rescue, and Education Center in Iquitos, Peru, we calculated the number of repeat surveys needed to detect at least one individual with 95% (n = 3.10) and 99% (n = 4.76) confidence. We used both generalized linear mixed-effect models and Bayesian single-species and single-season detection models to determine the effects of the environment (water depth, water transparency, cloud cover, wind speed), time of day, and behavior (breathing, foraging, milling) on the time-to-detection and detection probability, respectively. Both models indicated a significant interaction between water depth and water transparency, causing an increase in the time-to-detection (β = 0.032; 95% CI = 0.028, 0.037) and a decrease in the probability of detecting manatees (α = -0.65; 95% CI = -1.3, -0.007), which was calculated to be 0.62 (95% CI = 0.23, 0.94). Due to the similarities between the lake and in situ habitats, the results of this study could be used to design in situ UAV survey protocols for Amazonian manatees or other difficult-to-detect freshwater aquatic mammals and to monitor ex situ animals pre-and post-release, which should ultimately contribute to a better understanding of their spatial ecology and facilitate data-driven conservation efforts.

Chronotype, Time of Day, and Children’s Cognitive Performance in Remote Neuropsychological Assessment

Research on the influence of chronotype and time of day (TOD) on cognitive performance, especially in children, is limited. We explored potential interactive effects, hypothesizing that performance differs when comparing preferred vs. non-preferred TOD. In total, 76 morning-type (MT = 37) or evening-type (ET = 39) children from the third and fourth grades (48.7% girls; M age = 8.05; SD age = 0.51), identified through the Children Chronotype Questionnaire, completed two 30-min neuropsychological assessment sessions via videoconference on the first (9:00) or last hour (16:00) of the school day. The protocol included neuropsychological tests targeting memory, language, and attention/executive domains. The results revealed an interactive effect of medium size between chronotype and TOD on a Rapid Alternating Stimulus (Naming) Task. MT and ET performed faster in asynchrony conditions (morning for ET; afternoon for MT). Additionally, ET outperformed MT in a Backward Digit Span Task, irrespective of TOD. TOD also influenced performance on an Alternating Verbal Fluency Task, with both MT and ET children performing better in the morning. These results underscore the importance of chronotype and TOD in children’s cognitive performance, particularly in working memory and verbal fluency. Children assessed during non-preferred TOD exhibited better performance on some cognitive tasks, challenging the assumption that optimal times always yield superior results.

Patient and public involvement and engagement (PPIE): how valuable and how hard? An evaluation of ALL_EARS@UoS PPIE group, 18 months on

BackgroundALL_EARS@UoS is a patient and public involvement and engagement (PPIE) group for people with lived experience of hearing loss. The purpose of the group is to share experiences of hearing loss and hearing healthcare, inform research and improve services for patients at University of Southampton Auditory Implant Service. A year after inception, we wanted to critically reflect on the value and challenges of the group. Four members of ALL_EARS@UoS were recruited to an evaluation steering group. This paper reports the evaluation of the group using the UK Standards for Public Involvement.MethodsAn anonymous, mixed-methods questionnaire was co-designed and shared with members of ALL_EARS@UoS using an online platform. The questionnaire was designed to capture satisfaction, individual feedback through free-text answers, and demographic information. Descriptive statistics have been used to express the satisfaction and demographic data. Reflexive thematic analysis has been used to analyse the free-text responses. Group engagement and activity data over time were monitored and collected.ResultsThe questionnaire response rate was 61% (11/18). Areas identified as strengths were ‘Communication’ and ‘Working together’. Five themes were developed from the thematic analysis; (1) Increased knowledge and awareness around the topic of hearing health for group members and wider society, (2) supporting research, (3) inclusivity within the group, (4) opportunity to make a difference for people in the future and (5) running of the group/group organisation. The data highlighted the value and challenges of PPIE. Members described feeling listened to and appreciation of being able to share experiences. Time of day and meeting format were identified as challenges as they affected who could attend the meetings. The ability to secure and maintain sufficient funding and time to support inclusive and diverse PPIE activities is a challenge for researchers.ConclusionsWe have identified how PPIE added value to both group members and researchers, emphasising the true benefit of PPIE. We have highlighted challenges we are facing and our plan to tackle these. We aim to continue to develop and sustain a group that reflects the diversity of the Deaf/deaf or hard of hearing community and of our local community.

Routineness of Social Interactions is Associated with Higher Affective Well-Being in Older Adults.

Some research conceptualizes routineness of daily life as an indicator of cognitive vulnerability that would lead to lower well-being in older age, whereas other research expects routineness to give rise to more meaning and stability in life and thus to higher well-being. Further research is needed to understand routineness in older adults in relation to cognitive abilities and well-being. This study examined routineness of social interactions. We examined data from an event-contingent experience sampling study with 103 Swiss community-dwelling older adults (aged 65 to 84 years). Participants completed in-lab cognitive assessments (reasoning, episodic memory, speed, vocabulary) and reported their well-being (positive affect, negative affect, life satisfaction). Over 21 days, participants reported the time and context of their social interactions (including modality, partner type, and location). Routineness of social interactions was defined as social interactions that occurred at the same time of day over the study period. It was calculated using recurrence quantification analysis. Linear regressions showed that higher routineness of social interaction in general, of social interaction through the same modality, and of social interaction with the same partner type were associated with higher positive affect. Higher routineness of social interaction in general was associated with lower negative affect. Routineness of social interactions was not associated with life satisfaction or cognitive abilities. A routine social life may increase older adults' affective well-being. Results are discussed in the context of activity engagement and time use in older age.

Beyond muscles: Investigating immunoregulatory myokines in acute resistance exercise - A systematic review and meta-analysis.

Myokines, released from the muscle, enable communication between the working muscles and other tissues. Their release during physical exercise is assumed to depend on immune-hormonal-metabolic interactions concerning mode (endurance or resistance exercise), duration, and intensity. This meta-analysis aims to examine the acute changes of circulating myokines inducing immunoregulatory effects caused by a bout of resistance exercise and to consider potential moderators of the results. Based on this selection strategy, a systematic literature search was conducted for resistance exercise intervention studies measuring interleukin (IL-) 6, IL-10, IL-1ra, tumor necrosis factor (TNF-) α, IL-15, IL-7, transforming growth factor (TGF-) β1, and fractalkines (FKN) before and immediately after resistance exercise in healthy individuals. Random-effects meta-analysis was performed for each myokine. We identified a moderate positive effect of resistance exercise for IL-6 and IL-1ra. Regarding IL-15 and TNF-α, small to moderate effects were found. For IL-10, no significant effect was observed. Due to no data, meta-analyses for IL-7, TGF-β1, and FKN could not be performed. No moderators (training status, type of exercise, risk of bias, age, sex, time of day, exercise volume, exercise intensity, exercise dose) of the results were detected for all tested myokines. Taken together, this systematic review and meta-analysis showed immediate positive effects of an acute resistance exercise session on IL-6, IL-1ra, TNF-α, and IL-15 levels.

Circadian Pattern in Restless Legs Syndrome: Implications for Treatment Posology

AbstractThe symptoms of restless legs syndrome (RLS) follow a circadian pattern, as inducated in the current RLS diagnostic criteria. Indeed, subjects with mild-to-moderate RLS suffer or not from RLS symptoms depending on the time of day, resembling an above-threshold state periodically followed by a below-threshold state. Although the circadian clock is crucial in the clinical features of RLS, research assessing the ultimate drivers of circadian rhythmicity is still very limited. In the present review, we show current evidence on circadian variations of neurotransmitters involved in the pathophysiology of RLS (systemic iron metabolism, brain iron homeostasis, adenosine, dopamine, glutamate, and endogenous opioids). Secondly, an overview of available therapies for RLS is presented, including information on current recommendations for symptomatic treatments in RLS.We discuss the importance of further research into the circadian oscillations that occur in RLS, so that they can be managed, and a protective below-threshold state can be established on an individualized basis. In addition, we also discuss the current dosing of the medications prescribed in RLS symptomatic treatments, and how circadian factors should be considered to better adjust dosing on an individualized basis and increase the therapeutic benefit.

Effects of Gender and Social Network Use on High School Students’ Emotional Well-Being during COVID-19

Various studies conducted during the COVID-19 pandemic have confirmed changes in online behaviour, with young people increasingly using social networks. This trend appears to correlate with a heightened risk of various psychological and emotional problems. The main aim of this study is to explore the patterns of social network use among high school students amidst the pandemic, particularly focusing on the presence of specific emotional problems and potential gender differences. In addition, this study aims to contribute to the existing body of knowledge on the influence of lockdown measures on adolescents. A probabilistic sample of N = 825 students from 20 high schools in Zagreb participated in this study. Alongside basic sociodemographic variables, this study assessed social network habits and emotional problems using the Depression Anxiety Stress Scales 21 (DASS-21). The findings indicate intensive social media engagement during the pandemic. The results of the MANOVA analysis (gender x daily time on social media) show significant effects of both the time spent on social networks and gender on mental health, while no interaction effect was observed. Female students and those who spend more time on social media have higher levels of depression, anxiety, and stress symptoms. These findings underscore the need for addressing emotional problems and habits in the virtual environment of high school students and implementing appropriate preventive and treatment interventions.

Implementation on Large-Scale Mobile Fitness App Usage Analysis for Smart Health

Understanding the determinants behind the exercise habits of urban residents, encompassing aerobic activities and training regimens, is of paramount importance for informed public policy formulation and urban planning. The utilization of mobile fitness app data, which characterizes exercise behaviors concerning time and location, offers a unique avenue for unveiling the key factors influencing physical activity. In this study, we conducted a comprehensive analysis of mobile fitness app data, collecting information from over 14,000 cellular towers and studying the exercise patterns of 4,000 users. Our rigorous investigation reveals that temporal elements, such as the day of the week and the time of day, wield significant influence over human exercise preferences. For instance, data shows that on weekdays, there's a 20% increase in exercise app usage during the evening hours (6 PM - 9 PM), while weekends see a 15% spike in early morning activities (6 AM - 8 AM). Geographical location also emerges as a prominent influencer. Our analysis indicates that individuals residing closer to parks or fitness centers exhibit a 25% higher likelihood of engaging in outdoor workouts. Importantly, personal income levels have surfaced as a fundamental factor significantly shaping exercise habits. Data suggests that individuals with higher incomes allocate, on average, 10% more of their time to structured training regimens. This research contributes essential insights for urban policy development and city planning, aimed at fostering a healthier and more physically active urban populace. Key Words: Tracking nutritional intake, Analyzing meals, Visualizing nutrition data, Daily nutrition overview, Calculating BMI, Image recognition for nutrition, Menu nutritional analysis, Tracking steps, Monitoring physical activity, Providing workout plans, Home workout routines, Gym workout routines, Planning a balanced diet, Diet plans based on BMI, Fitness and wellness application.

Time-of-day effects on ex vivo muscle contractility following short-term satellite cell ablation.

Muscle isometric torque fluctuates according to time-of-day with such variation owed to the influence of circadian molecular clock genes. Satellite cells (SC), the muscle stem cell population, also express molecular clock genes with several contractile related genes oscillating in a diurnal pattern. Currently, limited evidence exists regarding the relationship between SCs and contractility, although long-term SC ablation alters muscle contractile function. Whether there are acute alterations in contractility following SC ablation and with respect to the time-of-day is unknown. We investigated whether short-term SC ablation affected contractile function at two times of day, and whether any such alterations lead to different extents of eccentric contraction-induced injury. Utilizing an established mouse model to deplete SCs, we characterized muscle clock gene expression and ex vivo contractility at two times-of-day (morning 0700 h and afternoon, 1500 h). Morning-SC+ animals demonstrated ~25-30% reductions in tetanic/eccentric specific forces and, after eccentric injury, exhibited ~30% less force-loss and ~50% less dystrophinnegative fibers versus SC- counterparts; no differences were noted between Afternoon groups (Morning-SC+: -5.63 ± 0.61, Morning-SC-: -7.93 ± 0.61; N/cm2; p < 0.05) (Morning-SC+: 32 ± 2.1, Morning-SC-: 64 ± 10.2; dystrophinnegative fibers; p < 0.05). As Ca++ kinetics underpin force-generation, we also evaluated caffeine-induced contracture-force as an indirect marker of Ca++ availability, and found similar force reductions in Morning-SC+ vs SC- mice. We conclude that force-production is reduced in the presence of SCs in the morning but not the afternoon, suggesting that SCs may have a time-of-day influence over contractile-function.

Hydroxychloroquine-induced pigmentation in rheumatic diseases: prevalence, clinical features and influencing factors.

To describe the clinical features of Chinese patients with hydroxychloroquine (HCQ)-induced pigmentation and analyze the potential risk factors associated with HCQ-induced pigmentation. A cross-sectional study was conducted over a duration of 7 months, during which patients who had received HCQ treatment for >6 months were included. Data was collected through a structured questionnaire that encompassed demographic and geographic characteristics, information on HCQ and concomitant medication usage, sun exposure characteristics, and hyperpigmentation-related characteristics. Univariate and multivariate analyses were employed to calculate the statistical association between HCQ-induced pigmentation and multiple variables. Out of 316 patients, 83 (26.3%) patients presented hyperpigmentation during HCQ treatment. Hyperpigmentation presented after a median duration of HCQ treatment of 12 months (interquartile range, 6.0 months-30.0 months) with a median cumulative dose of 108 g of HCQ (interquartile range, 36-288 g). The most frequently affected sites of pigmentation were the face (60.2%), lower limbs (36.1%), and hands (20.5%). There was a linear decrease in the incidence of pigmentation with increasing daily sun exposure time (p= 0.030). In the multivariate analysis, variables (cumulative HCQ dose and daily sun exposure time) were included in the final models. The results revealed an independent correlation between HCQ-induced pigmentation and daily sun exposure exceeding 1 h (OR: 0.431; 95%CI: 0.208-0.892; p= 0.023). The occurrence of HCQ-induced pigmentation is not uncommon, with an incidence rate of 26.3%. Daily sun exposure time exhibited a protective effect against HCQ-induced pigmentation.

Online feeding behavior monitoring of individual group-housed grow-finish pigs using a low-frequency RFID electronic feeding system

Abstract Early identification of animals in need of management intervention is critical to maximize animal health and welfare and minimize issues with productivity. Feeding behavior, captured by automated feeding systems, can be used to monitor the health and welfare status of individual pigs. Here, we present a framework for monitoring feeding behavior of grow-finish pigs in real-time, using a low-frequency radio frequency identification (RFID) system. Using historical data, an autoregressive linear model for predicting daily time at the feeder was developed and utilized to detect anomalous decreases in feeding behavior associated with health status of the pig. A total of 2,826 pigs were individually monitored with our warning system over the entire grow-finish period, and health warnings were compared to caretaker diagnoses. The system detected 55.7% of the caretaker diagnoses, and on average these events were detected 2.8 days earlier than diagnosis by the caretaker. High numbers of potentially spurious health warnings, generated by the system, can be partly explained by the lack of a reliable and repeatable gold standard reference data set. Results from this work provide a solid basis for monitoring individual animals, but further improvements to the system are necessary for practical implementation.

The relationship between screen time and gross motor movement: A cross-sectional study of pre-school aged left-behind children in China.

To investigate the level of screen time and gross motor movement level and the correlation between them in left-behind children aged 3 to 6 years old in China. A randomized whole-group sampling method was used to study 817 left-behind children aged 3-6 years in 15 kindergartens in Xiangcheng city, Henan province. The third version of the Test of Gross Motor Development (TGMD-3) was used to test the children's gross motor movement level, and the screen time questionnaire was used to test the children's screen time level. The relationship between the two and the indicators was explored using Pearson's two-sided correlation and multilevel regression. The average daily screen time of left-behind children aged 3-6 years old increased with age, and the reporting rate of >2 h/d ranged from 22.43% to 33.73%; gross motor movement of left-behind children aged 3-6 years old increased with age, with significant differences between age (p<0.05). There was a low to moderate negative correlation (r = -0.133 to -0.354, p<0.05) between screen time and gross motor movement in children aged 3-6 years, and multiple regression analysis showed that screen time was predictive of gross motor movement in children (p<0.05), with an explanation rate of 21.4%. There is a correlation between screen time and gross motor movement development in children aged 3-6 years old left behind, and the gross motor movement ability of children aged 3-6 years old can be developed by reducing screen time and increasing physical activity.

Association Between Park Use and Moderate-to-Vigorous Activity During COVID-19 Years among a Cohort of Low-Income Youth.

Neighborhood parks are important venues to support moderate-to-vigorous (MVPA) activity. There has been a noticeable increase promoting physical activity among youth in neighborhood parks. This paper aims to assess the association between park use and MVPA among low-income youth in a large urban area. We recruited a cohort of 434 youth participants during the COVID pandemic years (2020-2022) from low-income households in Washington, D.C. We collected multiple data components: accelerometry, survey, and electronic health record data. We explored the bivariate relationship between the accelerometer-measured daily MVPA time outcome and survey-based park use measures. A mixed-effect model was fitted to adjust the effect estimate for participant-level and time-varying confounders. The overall average daily MVPA time is 16.0min (SD = 12.7). The unadjusted bivariate relation between daily MVPA time and frequency of park visit is 1.3min of daily MVPA time per one day with park visits (p < 0.0001). The model-adjusted estimate is 0.7 daily MVPA minutes for 1day with park visit (p = 0.04). The duration of a typical park visit is not a significant predictor to daily MVPA time with or without adjustments. The initial COVID outbreak in 2020 resulted in a significant decline in daily MVPA time (- 4.7min for 2020 versus 2022, p < 0.0001). Park visit frequency is a significant predictor to low-income youth's daily MVPA time with considerable absolute effect sizes compared with other barriers and facilitators. Promoting more frequent park use may be a useful means to improve low-income youth's MVPA outcome.