Light Duration Research Articles

How environmental conditions affect sleep? An investigation in domestic dogs (Canis lupus familiaris)

Studies with humans and some other animal species have shown that sleep is compromised when the presence of external factors such as light, sound, and temperature surpass normal levels. This study investigated the effects of these environmental conditions on 13 kennelled laboratory dogs, assessing whether each variable interfered with their sleep behaviour and/or increased stress responses, which could further compromise sleep quality. The behaviour of dogs was video recorded for eight months. Diurnal and nocturnal behaviour were recorded, along with naturally occurring levels of temperature, light and sound in the dogs’ kennel environment. Faecal cortisol metabolites (FCM), from samples collected every morning, were used to monitor the dogs’ adrenocortical activity. GLMM models and non-parametric tests were conducted to evaluate the relationship between sleeping patterns, environmental variables, and stress on the studied dogs. Nocturnal sleep decreased in response to increases in temperature and in day light duration. No effects of sound and FCM levels on dogs’ sleep were observed. However, diurnal sleep was affected by sound and FCM levels, decreasing when both factors increased. Additionally, noisier days increased stress responses, especially in male dogs. Increased FCM levels were associated with changes in the diurnal behaviour of dogs; for example, decreased activity. The decrease in daily activities and increased physiological stress responses could be associated with maladaptation to the environment, which could indicate poor welfare. Our study suggests that mitigating the impact of environmental conditions in the kennels could improve sleep quality and the overall quality of life of the dogs.

0615 Association between Ambient Light Exposure and Sleep Duration among American Adults from Varying Race/Ethnicities: Findings from the National Health and Nutrition Examination Survey

Abstract Introduction One in three American adults are sleep deprived in the United States (US). Racial/ethnic minorities are more likely to experience shorter sleep duration than are whites. Light exposure is associated with sleep duration. However, whether this association is independent of individuals’ race/ethnicity has not been studied in a nationally representative sample of the US adult population. We examined associations between ambient light exposure and sleep duration and between race/ethnicity and sleep duration. We also assessed whether associations between light exposure and sleep duration are independent of participants’ race/ethnicity. Methods We used data from the National Health and Nutrition Examination Survey (n=4,277 adults; 2013-2014). Participants (≥ 18 years old) wore an actigraph that collected 24-hour sleep/wake and light data for 7 consecutive days. Objective measurements in our analyses included sleep duration (valid minutes) and light exposure (lux). To determine the associations between light exposure and sleep duration, a weighted mixed-effects linear model was estimated controlling for age, sex, family income to poverty ratio, education, employment, marital status, homeownership status, birthplace, household size, vitamin D, smoking, physical activity, sedentary lifestyle, health status, body mass index, depression, chronic conditions, and time in days. A product term between lux and race/ethnicity was included in a second regression model. Results Participants had a mean sleep duration of 468.2 minutes. On average, White adults had the longest sleep duration (mean=478.8), followed by other/multiple races (mean=458.6), Asians (mean=449.1); Blacks (mean=445.0), and Hispanics (mean=444.7). Overall, light exposure was negatively associated with sleep duration (= -0.08 lux; p<0.001). Black slept significantly less than did Whites (= -37.1 p<0.001) followed by Asians ( = -26.5; p<0.01) and Hispanics (= -24.6; p<0.01). The association between light exposure and sleep duration did not significantly differ across all race/ethnic groupings, except for Blacks (= -0.05; p<0.01). Conclusion To our knowledge, this is the first study that used national data to assess racial/ethnic disparities in objectively measured light exposure. Future research is needed to shed more light on racial/ethnic disparities in the light-exposure-sleep-duration link. Support (If Any) R01HL142066, R01HL095799, RO1MD004113, R01HL152453, R25HL105444

0336 Sleep Time and Risk Taking Behaviour in Night Shift-Workers

Abstract Introduction Night shift-workers are integral in a multitude of industries. Many night shift-workers experience sleep loss, which may impact their risk taking behaviour.This study aimed to identify the correlation between total sleep time (TST) and shift-workers' engagement in risk-taking behavior. Methods 53 night shift-workers participated in the experiment. Polysomnography was conducted to determine the TST of shift-workers prior to completing a task that measured risk taking behaviour. This task simulated a driving scenario in which participants must decide whether or not to proceed at a yellow traffic light. Participants were not informed of the duration of the yellow light, which varied unpredictably in duration. The task consisted of 16 trials, and participants earned points that translated to a cash incentive (25 points = 25 cents). Participants either earned or lost 25 points depending on the success of each trial. Failure was defined as running a red light. Those who proceeded at every trial were categorized as insensitive to risk. Results The data revealed that those insensitive to risk had a significantly lower TST value.Those insensitive to risk had a lower mean sleep time (374 minutes, SD=75) compared to those sensitive to risk (415 minutes, SD= 42), p =.01 (Cohen’s d=0.67). Conclusion Sleep time is associated with risk-taking behavior in night shift-workers. This study offers insight into the amplification of risk taking behaviours within night shift-workers posed by sleep loss, possibly leading to errors and injuries in the workplace. This association may also suggest that implementation of measures to increase sleep for night shift-workers could decrease risk-taking behaviours. Support (If Any) K23HL133186

Night-to-night associations between light exposure and sleep health.

Previous research has demonstrated that exposure to light preceding and during sleep is associated with poor sleep, but most research to date has utilized either experimental or cross-sectional designs. The current study expands upon prior studies by using a microlongitudinal design that examines the night-to-night associations between light and sleep health in a diverse sample of adults (pre-registered at osf.io/k5zgv). US adults aged 18-87 years from two parent studies (N=124) wore an actiwatch for up to 10 nights. Light variables estimated from actigraphy include both average exposure and time above light threshold of 10 (TALT10 ) and 40 (TALT40 ) lux both during sleep and for the 1-hr preceding sleep. Actigraphy-based sleep variables included sleep offset, duration, percentage and fragmentation index. Higher average light exposure during sleep was associated with a later sleep-offset time, lower sleep percentage and higher fragmentation index (all p < 0.01). More minutes of TALT10 during sleep was associated with later sleep timing, lower sleep percentage and higher fragmentation index (all p < 0.01), and greater TALT40 during sleep was associated with lower sleep percentage. Light exposure was not related to sleep duration. In summary, greater light exposure during sleep was related to poorer sleep continuity and later wake time. The lack of association between light and sleep duration may be the result of compensating for sleep disruption by delaying wake time. Multi-level interventions to consistently reduce light levels during sleep should be considered.

Effect of LED lighting duration on biochemical composition of microgreens of white cabbag

In recent years, there has been a steady increase in public interest in healthy and balanced foods all over the world. In this respect, the microgreens of white cabbage is a source of a wide range of useful substances and is characterized by a higher content of those, compared with a similar commercial vegetable. At the same time, information about technological aspects of cultivation, which relate to the duration of lighting, about their correlation with biochemical composition of microgreens of industrial varieties and hybrids of this crop is insufficient and is limited to a very narrow set of their parameters. For this reason, it is of particular relevance to identify the optimal duration of LED lighting in the white cabbage microgreens crop, which ensures accumulation of the highest nutritional and vitamin value and determines the taste qualities of this product. The results of a comparative study of 14 quantitative parameters of biochemical composition of white cabbage microgreens (content of dry, tannic and pectin substances, free organic, ascorbic and hydroxycinnamic acids, soluble sugars, the main groups of bioflavonoids – i.e. anthocyanins, leucoanthocyanins, catechins, flavonols and the indicator of sugar acid index) with different duration of LED lighting are presented (8, 10, 12, 14 and 16 hours). The less significant effect of the studied factor on biochemical composition of microgreens was revealed at 10 hour exposure, while the maximum, exceeding it three times, was at 16 hour exposure. It has been shown that the highest integral level of nutritional and vitamin value of products according to the total analyzed indicators was provided at 16 hours of LED lighting, while the minimum – at 8 hours. For the first time in the Republic of Belarus, the optimal duration of LED lighting for the accumulation of physiologically valuable compounds by microgreens of white cabbage was revealed, which made it possible to recommend it to be used for industrial production.

DESAIN SISTEM KONTROL PENANGGULANGAN KEMACETAN LALU LINTAS ADAPTIF BERBASIS PLC

Traffic lights play an important role at every intersection in minimizing congestion, especially at intersections three and four. Today, the most common setting for traffic lights involves setting a fixed time. This pattern applies throughout the day, although the density of vehicles at each crossing is different. As a result, traffic jams on one side of the intersection are often unavoidable. Based on these problems, in this study an adaptive traffic light control system based on Programmable Logic Controller was built. In this test, the amber and green lights are set to about 3 and 5 seconds, respectively. During crowded situations, the duration of the green light is reduced to 10 seconds. It has been determined through testing that when the traffic light sensor detects a traffic jam, the green light will be on for 10 seconds, while under normal conditions it will be on for 5 seconds.

Implementation of Multi Level Traffic Controlling System using IoT

Abstract: In civic areas, traffic system is one of the significant pointers to show the growth and progress of a megacity and it also influences the quality of life of people living in metropolitan metropolises. In recent times, there's a significant increase in operation of road vehicles which is getting challenge for existing transportation system. The presently stationed traffic system isn't grounded on the traffic position and a predefined time is allocated for traffic signals at every road crossing which results in traffic congestion and situation becomes worst in the peak business hours. When traffic demand is great enough that the commerce between vehicles slows the speed of the traffic sluice, this results in some traffic. This high position business traffic contributes in the pollution by the emigration of CO 2 and several other adulterants in air. Also, it also causes tripling of the energy consumption and accordingly put adverse effects on the economy as well. To address the above problem, this paper presents the development of congestion level based dynamic traffic control system using IoT. It regulates the traffic lights duration grounded on the real time position of the traffic measured at the road crossings by using IR detectors. The development of this design is divided in three phases i.e., simulation and sense/logic development, development of IoT grounded system and eventually hardware implementation. In first phase the simulations are done in Proteus and results are presented in four cases i.e., normal routine, low position traffic, medium position traffic and high position traffic. In alternate phase the IoT grounded system is developed by making the communication link between the end bumps and the gateway over the internet. Eventually, the real- time prototype is enforced. In addition we're adding the features like Emergency Vehicle Traffic Clearance i.e., Ambulance or VIP Vehicles, Air Pollution discovery, Theft Vehicle Identification Point and Automatic parking. Keywords: Arduino Uno, IR sensor, LCD display, RF transmitter, Thing view App, RFID EM Module

Dexmedetomidine Improves Non-rapid Eye Movement Stage 2 Sleep in Children in the Intensive Care Unit on the First Night After Laparoscopic Surgery.

BackgroundPrevious studies have reported that children who were admitted to the ICU experienced a significant decrease in sleep quality compared to home. We investigated the effects of dexmedetomidine as an adjunct to sufentanil on the sleep in children admitted to the ICU on the first night after major surgery.MethodsThis is a prospective study From January to February 2022. Clinical trial number: ChiCTR2200055768, http://www.chictr.org.cn. Fifty-four children aged 1–10 years old children undergoing major laparoscopic surgery were recruited and randomly assigned to either the DEX group, in which intravenous dexmedetomidine (0.3 ug/kg/h) and sufentanil (0.04 ug/kg/h) were continuously infused intravenously for post-operative analgesia; or the SUF group, in which only sufentanil (0.04 ug/kg/h) was continuously infused. Patients were monitored with polysomnography (PSG) on the first night after surgery for 12 h. PSG, sleep architecture, physiologic variables and any types of side effects related to anesthesia and analgesia were recorded. The differences between the two groups were assessed using the chi-square and Wilcoxon rank-sum tests.ResultsFifty-four children completed data collection, of which thirty-four were 1–6 years old and twenty were aged >6 years. Compared to the SUF group, subjects in the DEX group aged 1–6 years displayed increased stage 2 sleep duration (P = 0.02) and light sleep duration (P = 0.02). Subjects aged >6 years in the DEX group also displayed increased stage 2 sleep duration (P = 0.035) and light sleep duration (P = 0.018), but decreased REM sleep percentage (P = 0). Additionally, the heart rate and blood pressure results differed between age groups, with the heart rates of subjects aged >6 years in DEX group decreasing at most time points compared to SUF group (P < 0.05).ConclusionDexmedetomidine prolonged N2 sleep and light sleep duration in the pediatric ICU after surgery but had different effects on the heart rate and blood pressure of subjects in different age groups.

Characterization of Occupational Lifting Patterns with Exposure Variation Analysis. Cross-sectional Workplace Study among Blue-Collar Workers.

To investigate and characterize the influence of sex, age, muscle strength, and cardiovascular fitness on manual lifting patterns using exposure variation analysis (EVA) during a full working day among blue-collar workers. Muscular activity (surface electromyography [sEMG]) of the thigh, low-back, and shoulder was measured throughout the working day in 173 employees with manual lifting tasks from 14 workplaces. Relative sEMG loading was expressed as % of maximal voluntary contraction (MVC). As an additional and more practically oriented analysis, calibration of load from standardized box lifts (5, 10, 20, and 30 kg) identified corresponding sEMG values in kg. Using an EVA 'lifting periods' of [1 to 5, >5 to 10, >10 to 20, >20 to 30, and >30] kg in time intervals [0 to 0.5, >0.5 to 1, >1 to 2, >2 to 5, >5 to 10, and >10] s were identified. Arm elevation and back inclination were measured using accelerometers. Females and older workers (≥50 years) primarily used the thighs for lifting and were exposed to more frequent thigh muscle 'lifting periods' of varying duration and load and performed more thigh lifts >30 kg and >60% of MVC compared with males and younger workers (P < 0.05). Females had less brief shoulder lifting periods and more work with bent back >30° than the males (P < 0.05), whereas stronger workers performed more work with elevated arm >60° and >90° than workers with low muscle strength (P < 0.05). However, besides a single difference where workers with lower cardiovascular fitness were exposed to more light (1-5 kg) and moderate duration (5-10 s) trapezius loading, the number of lifting periods was not affected by muscle strength nor cardiovascular fitness (P > 0.05). This EVA demonstrated sex- and age-related differences in exposure to lifting periods involving shoulder and thigh muscles.

Model Predictive Traffic Control by Bi-Level Optimization

A bi-level model for traffic signal optimization is developed. The model predictive framework is applied for traffic control in an urban traffic network. The potential of the bi-level formalization is used to increase the space of control influences with simultaneous evaluation of the green light and cycle durations. Thus, the increased control space allows more traffic parameters to be considered, such as vehicles queues and traffic flows. A particular modification of the bi-level control is applied for the synchronization of the traffic lights in the network. The model predictive approach is used for the real-time management of the traffic in the network. The control implementations are constrained by the shortest evaluated cycle. Thus, a synchronization of the traffic lights is applied for the minimization of the queues and maximization of the outgoing flows from the network. The bi-level model has been numerically tested on a set of intensive crossroads in Sofia. The numerical simulations prove the superiority of the developed bi-level control in comparison with the classical optimization of queue lengths.

The Basic Vegetative Phase and Photoperiod Sensitivity Index as the Major Criteria for Indigenous Upland Rice Production in Thailand under Unpredictable Conditions

Indigenous upland rice (Oryza sativa L.) is an important staple food for people. The productivity of upland rice is generally lower than lowland rice since crop yield depends on the amount of rainfall. Climate change is a major problem in rice production due to the unpredictable rainfall. The flowering time, maturity days, growth duration, and photoperiod sensitivity in rice are important for determining productivity. Therefore, in this study, indigenous upland rice germplasm was classified according to their flowering-related traits in the basic vegetative phase (BVP), photoperiod sensitivity index (PSI), grain yield (GY), and yield components. The results reveal that the BVP ranges from 12 to 76 days (mainly less than 30 days) while the PSI ranges from −0.14 to 0.89. Classification of the three groups was based on the PSI: 24 insensitivities (G1; PSI = −0.14–0.30), 214 weakly sensitive (G2; PSI = 0.31–0.70), and 63 strongly sensitive (G3; PSI = 0.71–0.89). Grain yield showed different correlations with day to flowering (DTF), PSI, and BVP in each group. The results suggest that the selection criteria were not only based on GY and DTF but also PSI and BVP. The new ideotypes for upland rice selection under unpredictable conditions such as rainfall and light duration are weakly sensitive (PSI range 0.30–0.60), low BVP (20–30 days), and less than 105 days of DTF, such as ULR189, ULR039, ULR036, ULR403, ULR364, ULR342, and ULR245 genotypes.

Effect of Artificial Lighting Duration on Egg Production and Egg Quality of Local Chickens

Low egg production and long ovulation interval among chickens are the problems faced by farmers. Thus, an appropriate technology for increasing egg production is necessary. This study aims to analyze the effect of artificial light duration on egg production and egg quality of local chickens. This experiment, which has a completely randomized design, was conducted in the city of Palu, between December 2017 and September 2018. The hens were divided into G0 (control; 12 h lighting), G1 (13 h lighting), G2 (14 h lighting), and G3 (16 h lighting). Research variables were follicle-stimulating hormone (FSH) and luteinizing hormone (LH) concentration, egg production, clutch, and egg quality. Egg production was significantly influenced by the addition of light but not the quality of local-chicken eggs (egg weight, egg yolk index, egg white index, air sack diameter, yolk color, and shell thickness). Nonetheless, artificial light in G2 (12 h natural day light + 2 h artificial light) significantly influenced the increase of both FSH and LH concentrations at approximately 235.57 pg/ml (range, 162.15–397.72 pg/ml) and 1,021.98 pg/ml (range, 2,521.08–3,543.06 pg/ml), respectively. Chickens raised under a 14-hour artificial light achieved an increase in egg production without affecting egg quality. Keywords : Artificial light, Egg Production, Quality of Egg, Local-chicken DOI : 10.7176/JBAH/12-8-03 Publication date : April 30th 2022

Intelligent Traffic Control System for Congestion Control, Ambulance Clearance and Stolen Vehicle Detection

Abstract: Over the years, the number of vehicles has increased dramatically, which has led to serious problems such as traffic jams, accidents, and many other problems, as cities turn into smart cities. In recent years, traffic jams have become one of the main challenges for engineers and designers to create an intelligent traffic management system capable of effectively detecting and reducing the overall density of traffic in most urban areas. This paper presents an intelligent traffic control system to pass emergency vehicles smoothly. Each individual vehicle is equipped with special RFID tag (placed at a strategic location), which makes it impossible to remove or destroy. We use RFID reader, NSK EDK-125–TTL and PIC16F877A system-on-chip to read the RFID tags attached to the vehicle. It counts number of vehicles that passes on a particular path during a specified duration. It also determines the network congestion, and hence the green light duration for that path. If the RFID-tag-read belongs to the stolen vehicle, then a message is sent using GSM SIM300 to the police control room. Also, when an ambulance is approaching the junction, it will communicate to the traffic controller in the junction to turn on the green light. This module uses ZigBee modules on CC2500 and PIC16F877A system-on-chip for wireless communications between the ambulance and traffic controller. The prototype was tested under different combinations of inputs in our wireless communication laboratory and experimental results were found as expected. Keywords: ZigBee, CC2500, GSM, SIM300, PIC16F877A, Ambulance Vehicle, Stolen Vehicle, Congestion Control, Traffic Junction.

ВЛИЯНИЕ ПРОДОЛЖИТЕЛЬНОСТИ СВЕТОДИОДНОГО ОСВЕЩЕНИЯ НА БИОХИМИЧЕСКИЙ СОСТАВ МИКРОЗЕЛЕНИ ГОРОХА ОВОЩНОГО

The results of a comparative study of the effect of the duration of LED lighting are presented (8, 10, 12, 14, 16 hour) on 13 characteristics of the biochemical composition of vegetable peas microgreens (Pavlusha variety) - the content of dry, tannic and pectin substances, free organic, ascorbic and hydroxycinnamic acids, soluble sugars, total protein and albumins, the main groups of bioflavonoids and the indicator of the sugar acid index. The dry matter content in the studied samples was 9.3-11.8 %, the content of free organic, ascorbic and hydroxycinnamic acids in the dry mass was 4.35-8.46 %, 359.8-487.8 mg/100 g and 1465.1-1956.0 mg/100 g, respectively. The content of soluble sugars was from 8.8 to 13.2 % with significant variant differences in the indicator of the sugar acid index, which varied in the range of 1.04-3.03. At the same time, the parameters of the accumulation of pectin substances were 3.884.54 %, the content of tannins - 1.23-1.92 %. The almost complete absence of anthocyanin pigments in the pea microgreens was found, the content of flavonols varied in the range of 1711.7-2189.2 mg/100 g, and catechins - 376.7-483.0 mg/100 g. At the same time, a high content of proteins and their valuable part - soluble proteins (albumins), which varied in mg/g of dry weight in the ranges of 412.3-443.4 and 8.38-18.0, was found in the microgreens. The considerable width of the ranges of variation of the biochemical characteristics of the micro-green peas testified to their significant dependence on the duration of LED lighting, which was ambiguous. The least significant changes in the biochemical composition of peas microgreens relative to the control (12 hours duration) were detected at 10 and 14 hours of illumination duration, while the greatest - at 8 and especially at 16 hours duration. At the same time, the highest integral level of nutritional and vitamin value of products according to the totality of biochemical characteristics is set at 14 hours of illumination, while the minimum is at 8 hours.

Direct Effects of Light on Sleep under Ultradian Light-Dark Cycles Depend on Circadian Time and Pulses Duration.

Ultradian light–dark cycles in rodents are a precious tool to study the direct effects of repeated light exposures on sleep, in order to better understand the underlying mechanisms. This study aims to precisely evaluate the effects of light and dark exposures, according to circadian time, on sleep and waking distribution and quality, and to determine if these effects depend on the duration of light and dark pulses. To do this, mice were exposed to 24 h-long ultradian light–dark cycles with different durations of pulses: T2 cycle (1 h of light/1 h of dark) and T7 cycle (3.5 h of light/3.5 h of dark). Exposure to light not only promotes NREM and REM sleep and inhibits wake, but also drastically alters alertness and modifies sleep depth. These effects are modulated by circadian time, appearing especially during early subjective night, and their kinetics is highly dependent on the duration of pulses, suggesting that in the case of pulses of longer duration, the homeostatic process could overtake light direct influence for shaping sleep and waking distribution.

Metal Free Porphyrin Photocatalyst Comprising Ionic Liquid with Electron Donor Acceptor Moiety for Visible Light Assisted Oxidative Amination

AbstractMetal leaching and stability of heterogeneous catalysts is the main concern in pharmaceutical, fine chemical industries, enhancing metal contamination of the product. In this protocol, we report design and characterizations of a metal free porphyrin (MFPc) photocatalyst with electron donor acceptor (dicyano) moiety, for oxidative amination of benzyl amine under irradiation of 5 W LED light in a home‐made photoreactor. Contrasted with the poor photocatalytic property of different derivatives of porphyrins, MFPc presents a significant improvement in imine formation (83 %). The influence of various factors including quantity of catalyst, duration, and intensity of light (512 W), for oxidative amination were explored. MFPc with favourable properties like Hammett acidity (1.11), band gap (1.37 eV), explored for the synthesis of pharmaceutically important benzimidazole, from o‐phenylene diamine. Moreover, MFPc displayed good reusability for 6 consecutive runs with negligible decrease in yield of imine at ambient reaction conditions. Additionally, a probable mechanism for imine formation was proposed.

Electrodermal activity based autonomic sleep staging using wrist wearable

Autonomic sleep staging refers to sleep characterization using autonomic physiological signals. This paper focuses on utilizing electrodermal activity (EDA), an autonomic signal that reflects the activity of sympathetic nerves on sweat glands, for characterizing wake and three sleep stages viz., light, deep, and rapid eye movement (REM) sleep. The study also investigates whether skin temperature (ST) measured from the same skin site as EDA can enhance the performance of EDA-based sleep staging. EDA and ST during sleep were recorded overnight to generate 118 datasets with an average duration of 6.2 h. Recordings were done from the dominant ventral wrist of all subjects using a GEN II wrist wearable vital signs monitor (VSM) from Analog Devices. WatchPAT, an FDA-approved, portable sleep monitor was used as a reference to generate the ground truth. 204 features were extracted from 30-s epochs of raw and preprocessed EDA and ST signals. Feature selection using a novel ensemble wrapper method was adopted to identify the best feature subset. User-specific, general, and non-intersecting ordinal models based on 7 classifiers were investigated, concerning their utility for sleep staging. While the EDA-based scheme using the non-intersecting ordinal random forest classifier yielded the highest training accuracy of 88.11% for females and 88.75% for males, the addition of ST enhanced it to 96.29% and 95.06%, respectively. The scheme exhibited good generalizability on a new dataset, yielding an accuracy of 94.11% for females and 92.92% for males. The duration of wake, light, deep, and REM was estimated as a percentage of total sleep duration and was validated against the reference. The sleep estimates showed a positive correlation with Pearson’s r of 0.97, 0.96, 0.96, and 0.98 respectively for %Wake, %Light, %Deep, and %REM. The Bland–Altman analysis done on estimates also indicated similarity with minimal bias.

The neighborhood physical environment and the 24-hour movement behavior composition among children

ABSTRACT The time spent in sleep, sedentary behavior, and physical activity form a 24-hour movement behavior composition. The objective was to identify neighborhood physical environment features associated with multiple components of the movement behavior composition among 10 to 13-year-olds. Twenty-three neighborhood physical environment features were measured in 1 km buffers from the participantsʻ homes and from these walkability, traffic safety, dedicated play spaces, non-dedicated play spaces, noise, and artificial light indices were created. Moderate-to-vigorous physical activity, light physical activity, sedentary time, and sleep duration were measured. Compositional data analysis was used to establish differences in movement behaviors according to neighborhood physical environment features. One hundred and sixteen associations, reflecting four movement behaviors X 29 environment variables and indices, were examined. Only three of these were statistically significant. Therefore, neighborhood physical environment features were not meaningful correlates of 24-hour movement behaviors.

Investigation of the aging clock's intermittent-light responses uncovers selective deficits to green millisecond flashes.

The central pacemaker of flies, rodents, and humans generates less robust circadian output signals across normative aging. It is not well understood how changes in light sensitivity might contribute to this phenomenon. In the present study, we summarize results from an extended data series (n=5681) showing that the locomotor activity rhythm of aged Drosophila can phase-shift normally to intermittently spaced episodes of bright polychromatic light exposure (600lx) but that deficits emerge in response to 8, 16, and 120-millisecond flashes of narrowband blue (λm, 452nm) and green (λm, 525nm) LED light. For blue, phase-resetting of the activity rhythm of older flies is not as energy efficient as it is in younger flies at the fastest flash-exposures tested (8 milliseconds), suggesting there might be different floors of light duration necessary to incur photohabituation in each age group. For green, the responses of older flies are universally crippled relative to those of younger flies across the slate of protocols we tested. The difference in green flash photosensitivity is one of the most salient age-related phenotypes that has been documented in the circadian phase-shifting literature thus far. These data provide further impetus for investigations on pacemaker aging and how it might relate to changes in the circadian system's responses to particular sequences of light exposure tuned for wavelength, intensity, duration, and tempo.

Aging and Light Stress Result in Overlapping and Unique Gene Expression Changes in Photoreceptors.

Advanced age is one of the leading risk factors for vision loss and eye disease. Photoreceptors are the primary sensory neurons of the eye. The extended photoreceptor cell lifespan, in addition to its high metabolic needs due to phototransduction, makes it critical for these neurons to continually respond to the stresses associated with aging by mounting an appropriate gene expression response. Here, we sought to untangle the more general neuronal age-dependent transcriptional signature of photoreceptors with that induced by light stress. To do this, we aged flies or exposed them to various durations of blue light, followed by photoreceptor nuclei-specific transcriptome profiling. Using this approach, we identified genes that are both common and uniquely regulated by aging and light induced stress. Whereas both age and blue light induce expression of DNA repair genes and a neuronal-specific signature of death, both conditions result in downregulation of phototransduction. Interestingly, blue light uniquely induced genes that directly counteract the overactivation of the phototransduction signaling cascade. Lastly, unique gene expression changes in aging photoreceptors included the downregulation of genes involved in membrane potential homeostasis and mitochondrial function, as well as the upregulation of immune response genes. We propose that light stress contributes to the aging transcriptome of photoreceptors, but that there are also other environmental or intrinsic factors involved in age-associated photoreceptor gene expression signatures.