Diurnal Behavior Research Articles

Artificial light at night alters diurnal and nocturnal behavior and physiology in green anole lizards

Artificial light at night (ALAN) disrupts biological rhythms across widely diverse organisms. To determine how energy is allocated by animals in different light environments, we investigated the impacts of ALAN on behavior and physiology of diurnal green anole lizards (Anolis carolinensis). Two groups of 24 adult lizards (half males, half females) were maintained in a controlled lab setting for six weeks. One group was exposed to a simulated natural summer light-dark cycle; the other was exposed to ALAN that simulated urban, nocturnal light exposure. After an acclimation period, we conducted four behavioral trials. One trial examined behavioral time allocation over two 24 h periods, and three others were conducted during mid-day and mid-night: open field tests, to examine exploratory behavior; foraging trials, to examine prey consumption; and social interaction trials, to examine same-sex interactions. We then measured each lizard's snout-vent length and mass of its body, abdominal fat pads, liver, and, for males, testes. Lizards exposed to ALAN were more likely to be awake at night, using nocturnal light to explore, forage, and display to conspecifics. However, during the day, ALAN lizards were less likely to be awake, slower to move, and females displayed less frequently. ALAN lizards had heavier fat pads and testes, but ALAN did not impact body mass, liver mass, or snout-vent length. In sum, ALAN appears to cause a broad shift towards increased nocturnal activity and may alter metabolic and reproductive processes. Future work should examine the fitness consequences of these behavioral and physiological changes.

Characterization of the Complete Mitochondrial Genome of Eight Diurnal Hawkmoths (Lepidoptera: Sphingidae): New Insights into the Origin and Evolution of Diurnalism in Sphingids.

Simple SummaryWe newly sequenced the mitochondrial genomes of 22 species from three subfamilies in the family Sphingidae. The mitogenomes of six diurnal species were newly sequenced, assembled, and annotated in this study (Hemaris radians, Macroglossum bombylans, Macroglossum fritzei, Macroglossum pyrrhosticta, Neogurelca himachala, and Sataspes xylocoparis) and, together with those of two previously reported diurnal hawkmoths (Cephonodes hylas and Macroglossum stellatarum), were analyzed in terms of sequence length, nucleotide composition, relative synonymous codon usage, non-synonymous/synonymous substitution ratio, gene spacing, and repeat sequences. The phylogenetic relationships among the subfamilies of Sphingidae were analyzed to explore the origin, divergence time, and evolutionary status of diurnal sphingids. In addition, we performed divergence time estimation and reconstruction of ancestral characters. Diurnal behavior of hawkmoths first originated 29.19 million years ago (Mya) and may have been influenced by the combination of herbaceous flourishing, which occurred 26–28 Mya, the uplift of the Tibetan Plateau, and the large-scale evolution of bats in the Oligocene to Pre-Miocene. Moreover, diurnalism in hawkmoths had multiple independent origins.In this study, the mitochondrial genomes of 22 species from three subfamilies in the Sphingidae were sequenced, assembled, and annotated. Eight diurnal hawkmoths were included, of which six were newly sequenced (Hemaris radians, Macroglossum bombylans, M. fritzei, M. pyrrhosticta, Neogurelca himachala, and Sataspes xylocoparis) and two were previously published (Cephonodes hylas and Macroglossum stellatarum). The mitochondrial genomes of these eight diurnal hawkmoths were comparatively analyzed in terms of sequence length, nucleotide composition, relative synonymous codon usage, non-synonymous/synonymous substitution ratio, gene spacing, and repeat sequences. The mitogenomes of the eight species, ranging in length from 15,201 to 15,461 bp, encode the complete set of 37 genes usually found in animal mitogenomes. The base composition of the mitochondrial genomes showed A+T bias. The most commonly used codons were UUA (Leu), AUU (Ile), UUU (Phe), AUA (Met), and AAU (Asn), whereas GCG (Ala) and CCG (Pro) were rarely used. A phylogenetic tree of Sphingidae was constructed based on both maximum likelihood and Bayesian methods. We verified the monophyly of the four current subfamilies of Sphingidae, all of which had high support. In addition, we performed divergence time estimation and ancestral character reconstruction analyses. Diurnal behavior in hawkmoths originated 29.19 million years ago (Mya). It may have been influenced by the combination of herbaceous flourishing, which occurred 26–28 Mya, the uplift of the Tibetan Plateau, and the large-scale evolution of bats in the Oligocene to Pre-Miocene. Moreover, diurnalism in hawkmoths had multiple independent origins in Sphingidae.

Diurnal Variations in the Aphelion Cloud Belt as Observed by the Emirates Exploration Imager (EXI)

AbstractObservations by the Emirates eXploration Imager (EXI) on‐board the Emirates Mars Mission are used to characterize the diurnal, seasonal, and spatial behavior of aphelion cloud belt during Mars Year 36 LS ∼ 30°–190°. Building from previous work with the Mars Color Imager (MARCI) onboard the Mars Reconnaissance Orbiter, we retrieve water ice extinction optical depth (τice) with an uncertainty ±0.0232 (excluding particle size effects). We connect EXI and MARCI using radiance and τice. Zonal and meridional diurnal trends are analyzed over 6–18 hr Local True Solar Time. The retrievals show large morning‐evening asymmetries about a minimum near 12 hr. The latitudinal distributions in early morning are extensive and particularly striking near mid‐summer. Comparisons to the Mars Planetary Climate Model show reasonable agreement with basic diurnal behavior, but noticeable departures include too much water ice in early morning, the general latitudinal extent, and behavior at smaller scales like the volcanoes and other topographically distinct features.

3 Towards Automated Behavior Analysis for Individually Housed Piglets–Sampling Considerations

Abstract Behavior sampling is commonly applied to represent a complete picture of animal behavior. Traditional sampling methods often fail to capture complete sequences of events, diurnal behavior, or behavior patterns. As digital technologies allow more frequent collection of behavior, there is a need to understand if the potential increase in sampling frequency yields an increase in the knowledge we gain from additional observations. In this study, 24-h behavior was labelled for three individually housed research piglets, creating a ground truth dataset. An ethogram with five categories (resting, consumption, maintenance, exploratory, and social interactions) including 23 behavior labels was applied for behavior observation for every frame in the video data set. Using Python to automatically sample behavior data from the complete dataset, the results of instantaneous and continuous sampling strategies at various sampling intervals and times of day were compared with the ground truth continuous data set using a two-sample t-test for: (a) total percentage of observations, (b) average bout length, and (c) normalized number of occurrences. Results were considered significant for alpha< 0.05, which indicated a sampling method was different from ground truth. Continuously sampled data were collected at the start of each hour for 2, 5, 10, 15, and 20-min periods. Instantaneously sampled data were collected at the intervals: 1, 5, 10, 20, and 40-s; 1, 2, 5, 10, 20, and 60-min. Every sampling strategy resulted in misrepresentation of behavior. For example, results for the 1-s instantaneous sampling method (every 15th frame versus every frame) revealed that seven of the 23 behaviors observed were misrepresented in at least one metric: (a) total percentage of observations [P=0.027 (drinking behavior); P=0.027 (sham chewing), P=0.011 (head tossing)]; (b) average bout length [P=0.033 (feeding behavior), P=0.032 (nosing), P=0.040 (exploring pen), P=0.039 (head tossing)]; and (c) normalized number of occurrences [P=0.005 (exploring pen), P=0.018 (head tossing)].

Diurnal and Nocturnal Behaviour of Cheetahs (Acinonyx jubatus) and Lions (Panthera leo) in Zoos.

Simple SummaryTo date, few studies have examined both night-time and daytime behaviour of lions and cheetahs in zoos. To gain a deeper understanding of behavioural rhythms, this knowledge needs to be expanded. In our study, light was a strong influencing factor leading to different diurnal and nocturnal activity budgets. During the day, both species were significantly more active than during the night. These daily activity peaks correlated with feeding time. At night, lions showed increased resting behaviour with long sleep phases averaging more than 75 min per sleep event. Sleep phases are defined as minutes per sleep event with the animal’s body and head lying on the ground. The number of sleep phases, however, dropped slightly compared to the day. Cheetahs also had a higher length of sleep phases at night than during the day, although the increase was smaller than in lions. However, the number of sleep phases was significantly higher than during the day in all animals. Our results show that the behavioural rhythms of lions and cheetahs differ significantly during the day and night. The results show that studies that take into account 24-h rhythms are well suited to measure diurnal rhythms and, based on this, possibly derive statements on management and husbandry.Mammals are constantly exposed to exogenous and endogenous influences that affect their behaviour and daily activity. Light and temperature, as well as anthropogenic factors such as husbandry routines, visitors, and feeding schedules are potential influences on animals in zoological gardens. In order to investigate the effects of some of these factors on animal behaviour, observational studies based on the analyses of activity budgets can be used. In this study, the daily and nightly activity budgets of six lions (Panthera leo) and five cheetahs (Acinonyx jubatus) from four EAZA institutions were investigated. Focused on the influencing factor light and feeding, we analysed these activity budgets descriptively. Behaviour was recorded and analysed during the winter months over an observation period of 14 days and 14 nights using infrared-sensitive cameras. Our results show that lions and cheetahs exhibit activity peaks at crepuscular and feeding times, regardless of husbandry. Thus, lions in captivity shift nocturnal behaviour familiar from the wild to crepuscular and diurnal times. In cheetahs, in contrast, captive and wild individuals show similar 24 h behavioural rhythms. The resting behaviour of both species is more pronounced at night, with cheetahs having a shorter overall sleep duration than lions. This study describes the results of the examined animals and is not predictive. Nevertheless, the results of this study make an important contribution to gaining knowledge about possible factors influencing the behaviour of lions and cheetahs in zoos and offer implications that could be useful for improving husbandry and management.

Diurnality in the defensive behaviour of African honeybees Apis mellifera adansonii and implications for their potential efficacy in beehive fences

AbstractAcross the range of African elephants Loxodonta spp., negative interactions with people are prevalent, and the impact of the resulting economic losses on farmers calls for solutions. The use of beehive fences, a mitigation method with ecological and socio-economic benefits, is gaining momentum in African savannah landscapes. We assessed the diurnal and nocturnal defensive behaviours of African honeybees Apis mellifera adansonii in response to visual and physical disturbances in the Campo–Ma'an conservation area, Cameroon. We examined six bee colonies, assessing their activity level, aggressive behaviour and ability to defend themselves when disturbed at different times of day. We found that activity levels varied between colonies and that colonies were more active during the day and inactive at night. The defensive perimeter around the hives also varied between the colonies and was generally greater during morning and evening periods. Bee colonies did not defend their hives around midday and at night. In response to a threat, bees were more likely to fly out from the hive during daytime than at night, with variation amongst colonies. Overall, as elephant intrusions occur mostly at night, beehive fences alone may not be an adequate mitigation method against crop damage caused by forest elephants Loxodonta cyclotis. We suggest combining beehive fences with other mitigation methods to improve crop protection.

Spinner dolphin residency in tropical atoll lagoons: Diurnal presence, seasonal variability and implications for nutrient dynamics

AbstractMobile predators serve important ecological functions, including acting as nutrient vectors between different ecosystems. In coral reefs, pelagic nutrient subsidies are believed to play an increasingly important role under ongoing and projected environmental changes. Here, we combine visual sightings with passive acoustic monitoring to report habitat use and behaviour by cetaceans within atoll lagoons in the Maldives and Chagos archipelagoes. We demonstrate that spinner dolphins (Stenella longirostris) are the most widely distributed and numerically abundant cetacean inside these atolls (>90% of all individual cetaceans by numbers). Our visual and acoustic observations both provide evidence of a regular diurnal behaviour, where dolphins enter the lagoons during the morning, for day‐time resting, and exit during the afternoon, for night‐time foraging offshore. Using standard metabolic models and timing of lagoonal residencies, we estimate that a dolphin pod would deposit approximately 288 ± 17 kg year−1 of nitrogen of primarily mesopelagic origin inside the lagoons. The nitrogen deposited inside an atoll lagoon by a dolphin pod resident year‐round will therefore likely enhance coral reef productivity and resilience and suggests that these dolphins play a role in making pelagic energy and nutrients available to coral reefs. The absence of any acoustic detections following the reversal of the monsoon winds suggests that the short‐to‐medium‐term residency of the dolphins is sensitive to seasonal productivity dynamics.

Diurnal Chorusing in Nine Species of North American Anurans

A year-long survey of survey of diurnal frog calling behavior was conducted at the Red River Research and Education Park in Shreveport (Caddo Parish), Louisiana to investigate the prevalence of daytime breeding choruses in the species present at the park. We determined that 60% (9/15) of species known from the area participated in daytime breeding choruses. Four of these were new species reports for the behavior. One species was identified entirely based on a daytime chorus from outside the normal breeding season. Although we believe daytime chorusing is widespread in frogs, several species did not diurnally chorus during our study. Diurnal calling may be an important indicator of the peak breeding season for a species and it may also be a useful tool at times when night surveys are impossible.

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.

Comparison of bottomside ionospheric profile parameters (B0 and B1) extracted from FORMOSAT-7/COSMIC-2 GNSS Radio occultations with Digisondes and IRI-2016 model

The bottomside thickness (B0) and shape (B1) are two important parameters considered in the bottomside electron density profile (EDP) specification of the International Reference Ionosphere (IRI) model that is the most widely accepted global empirical ionospheric model. In the present study, we investigated B0 and B1 as derived from least-square fitting of FORMOSAT-7/COSMIC-2 (F7/C2) radio occultation (RO) profiles by employing certain quality constraints in accordance to coincident Digisonde soundings. We performed a comparative analysis of the local time diurnal, seasonal and latitudinal behaviour of B0 and B1 parameters from a huge database of F7/C2 profiles accumulated during the last two years (2020 and 2021) with estimations from the IRI-2016 submodels: Bil-2000, Gul-1987, and ABT-2009, referring to the bottomside profile characteristics during the low solar activity period of 25th solar cycle. The results reveal daytime underestimation and nighttime overestimation features of IRI submodels. The typical pre-sunrise enhancement in B0 is clearly discernible in the F7/C2 observations which could not be reproduced in any of the IRI submodels. Moreover, the equatorial bottomside thickness anomaly (EBTA) presenting hemispheric asymmetry is not evidenced in the observed as well as modelled parameters. The sharp changeover in B0 magnitude from summer to winter solstice hemisphere and spring to fall equinox hemisphere in Gul-1987 indicates its inability to accurately represent the B0 variation at the equatorial and low latitude sector. Despite the fact that ABT-2009 performs relatively better than Gul-1987 sub-model based on F7/C2 and Digisonde datasets in different seasons, we demonstrate that there is room for possible improvement in terms of B0 and B1 representation.

0137 Phase response curve for effects of school start times on students’ diurnal learning rhythm

Abstract Introduction School start times impose constraints on sleep-wake behaviour that can result in social jet lag. Here, we used university archived datasets (1) to test whether social jet lag was associated with lower grades, and (2) to assess the phase resetting effects of school start times on students’ diurnal learning behaviour. Methods Social jet lag was estimated in 33,645 university students by measuring the phase shift in their Learning Management System (LMS) login rhythm on school days relative to non-school days (LMS social jet lag). ANCOVA was used to test the association between LMS social jet lag and grade point average, adjusting for demographic variables. We constructed a phase response curve by plotting phase shifts on school days (LMS social jet lag) against the initial phase when students’ first class of the day took place. The initial phase was expressed relative to students’ LMS login rhythm on non-school days (LMS chronotype). Results Students with greater LMS social jet lag had a lower grade point average (ANCOVA: F9,32269 = 44.8, P < 0.001). Social jet lag was larger in students with a later LMS login rhythm on non-school days (later chronotype) and for earlier school start times. The phase response curve revealed that the direction and magnitude of social jet lag were strongly dependent on the phase of students’ diurnal rhythm when their first class of the day took place. Phase shifts of up to 12 h were observed when school start times occurred out of phase with students’ diurnal rhythm. Conclusion School start times have a profound impact on students’ diurnal behaviour. Students whose diurnal patterns of LMS logins were similar on both school days and non-school days obtained better grades than their peers with LMS social jet lag. Universities can potentially improve learning by scheduling classes at times that are better aligned with students’ diurnal learning rhythm. Support (If Any) Data storage and management were supported by the NUS Office of the Senior Deputy President & Provost and ALSET. The work was funded by the Ministry of Education, Singapore (MOE2019-T2-2-074) and the National Research Foundation, Singapore (NRF2016-SOL002-001).

Climatology of Medium-Scale Traveling Ionospheric Disturbances (MSTIDs) Observed with GPS Networks in the North African Region

We present for the first time the climatology of medium-scale traveling ionospheric disturbances (MSTIDs) by using Global Positioning System (GPS) receiver networks on geomagnetically quiet days (Kp ≤ 3) over the North African region during 2008–2016. The ionospheric Total Electron Content (TEC) were estimated from the dual-frequency GPS measurements, and the TEC perturbations (dTEC) data were derived from the estimated TEC data. We focused on the TEC perturbations (dTEC) associated MSTIDs and statistically analyzed its characteristics, occurrence rate, diurnal and seasonal behavior as well as the interannual dependence. The results show that MSTID is a local and seasonal dependence. The result reveals that occurrence of MSTIDs increases with solar activity. It also shows that MSTIDs predominantly propagates towards the South (equatorward). The MSTIDs event period is (12 ≤ period ≤ 53 min), while the dominant peak-to-peak amplitude is (0.08 ≤ amp ≤ ~ 1.5 dTECU). The study also shows that the amplitude of MSTIDs is higher at the northwest (Lat: ~ 32° N to ~ 38° N, Long: ~ 2° W to ~ 15° W) when compared with northeast (Lat: ~ 28° N to ~ 38° N, Long: ~ 23° E to ~ 40° E), and the disturbance occurrence time is more frequent within the hours of (1200–1600 LT), and (1000—1400 LT) in December solstice at daytime for stations located in the northwest and northeast part of the African region, respectively. While at the nighttime, the MSTIDs also exhibits variability in disturbance occurrence time around (northwest: 2100–0200 LT) and (northeast: 1900-0200 LT) in June solstice, but get extended to March equinox during solar maximum (2014). The mean phase velocity in daytime MSTIDs is higher than the nighttime in every season, except during June solstice.

Deficient Central Leptin Signaling “In Vivo” Alters Hypothalamic Levels of Circadian Clock Proteins Changing the Diurnal Eating Behavior in Rats

BackgroundLeptin, acting at CNS, decreases food intake (FI), body weight (BW) and adiposity, while circadian dysfunction induces hypothalamic leptin resistance associated to increased adiposity. Hence, we hypothesized that partial inhibition of hypothalamic leptin signaling “in vivo” would alter circadian rhythms resulting in changes in diurnal eating behaviors leading to increased adiposity and peripheral insulin resistance.Methods3‐months‐old Wistar rats were randomly assigned in two different groups: rats infused “in vivo” with saline (PBS) (n=12) or rats infused with a leptin antagonist (SLA) (0.2 micrograms/day) (n=12) via icv minipump insertion for 21 days. On day 0, rats were individually housed in metabolic cages and maintained for 21 days measuring daily BW, FI and locomotor activity. Hypothalamic proteomic analysis (n=6 per group) was carried out to determine if hypothalamic circadian proteins could be altered upon chronic SLA infusion. On day 21 and before sacrifice, one group of rats infused with PBS or SLA (n=6 per group) were injected icv with 100 ng of rat leptin in a volume of 2 microliters. 30 min later rats were euthanatized.ResultsSLA infusion decreased leptin‐induced phosphorylation of pY705‐STAT3 at the hypothalamus sustaining the induction of central leptin resistance upon chronic SLA administration. As a result, daily FI, final BW and visceral adiposity increased in SLA‐infused rats. Remarkedly, the diurnal eating behavior was altered in the SLA group of rats. In fact, daily FI was significantly increased by 48% only during the light phase in SLA infused vs PBS treated control rats, while in the dark phase FI increased less than 10% in the SLA group compared with control PBS‐infused rats. Moreover, SLA‐infused rats develop peripheral insulin resistance assessed by HOMA‐IR at the end of the treatment. Hypothalamic proteomic analysis revealed significant changes in 446 proteins, 266 were up‐regulated and 180 down‐regulated upon SLA infusion. Interestingly, proteins involved in the transcriptional activity of BMAL1/CLOCK were altered in SLA‐infused rats. Paraspeckle component 1, involved in the negative regulation of BMAL1/CLOCK, was over‐represented, while vasopressin‐neurophysin 2 copeptin, a positive regulator of circadian gene expression, was under‐represented.ConclusionOur results suggest that deficient hypothalamic leptin signaling is associated to circadian dysfunction which leads to changes in the diurnal eating behavior in rats resulting in increased adiposity and peripheral insulin resistance.

Measurements of aerosol particle concentrations in the atmosphere of the south-eastern coast of Lake Baikal (at Boyarsky station) in the summer of 2020

Atmospheric measurements of aerosol particle concentrations were made at a station named Boyarsky, the south-eastern coast of Lake Baikal (Russia) in the summer of 2020. The measurement period was conventionally divided into two ranges: 1) the smoke emission period of July 17-25; 2) the period of weakening of the influence of smoke emissions from forest fires in the neighbouring regions (from 14 August to 10 September). The diurnal behaviour of the total number concentrations of ultrafine particles in the size range from 5 to 200 nm (UFA) and submicron aerosols (SMA) from 0.2 to 1 μm was studied. The mean concentrations of UFA and SMA are 2705 (±1791) cm−3 and 40 (±19) cm−3 in July; 1247 (±780) cm−3 and 57 (±58) cm−3 in August; 1205 (±764) cm−3 and 37 (±19) cm−3 in September, respectively (the values in parentheses represent the respective standard deviations). The temporal evolution of the UFA particle number concentrations has shown a pronounced variation with lower concentrations in August-September and higher concentrations in July, whereas the diurnal patterns have been mostly found to be strongly influenced by the wildfire emissions. A strong relationship between the total particle number concentration has been established with the concentration of nitrogen dioxide NO2 (R =0.81), O3 (R = 0.66) and a weaker one with the concentration of sulphur dioxide (R =0.46). The thus obtained data on aerosol particle concentrations have been used to identify the events of bursts of nanoparticle formation in the atmosphere.

Replacement of soybean meal with alternative protein sources in the concentrate supplement for lactating Holstein × Gyr cows in an intensive tropical pasture-based system: Effects on performance, milk composition, and diurnal ingestive behavior

The purpose of this study was to evaluate the effects of total replacement of soybean meal (SBM) with three alternative protein sources in the concentrate supplement on performance, feed efficiency, milk composition, and diurnal ingestive behavior of Holstein × Gyr cows under an intensive system of grazing on tropical pasture. Twelve cows with 512 ± 61 kg of BW (mean ± standard deviation), 20.4 ± 4.14 kg/d of milk yield, and 86 ± 40 days in milk were distributed in a triplicated 4 × 4 Latin square design. The treatments consisted of four concentrate supplements formulated with SBM (Control), cottonseed meal (CSM), peanut meal (PM), or sunflower meal (SFM). The animals were kept in intensive rotational grazing (n = 24 paddocks) on Tanzania grass (Panicum maximum syn. Megathyrsus maximus) pasture, with 1 day of occupation per paddock and a stocking rate of 4.3 AU/ha. The daily amount of concentrate supplement offered to the cows was 1 kg DM of concentrate per 3 kg of milk produced. Fat-corrected milk yield (FCM) for the SBM group (21.1 kg/d) was similar to that of the other groups (21.5 kg/d on average); however, milk fat content and milk urea nitrogen were lower in the SBM group (36 g/kg and 12.6 mg/dL) than in the PM group (38.4 g/kg and 14.2 mg/dL). The protein source did not affect the intakes of DM (17.14 kg/d on average) and forage (9.66 kg DM/d on average). However, cows fed CSM had a lower concentrate supplement intake compared to those fed PM (7.11 vs. 7.78 kg DM/d). The lowest and the highest ether extract intake levels were observed in cows fed with SBM (0.31 kg/d) and CSM (0.39 kg/d). No effect of the protein source was detected on the time spent on grazing, rumination, and idleness, with mean values of 4.73, 2.01, and 5.26 h within a 12 h observation period (06:00–18:00 h). Soybean meal can be replaced with CSM, PM, or SFM in the concentrate supplement without affecting the FCM, feed intake, feed efficiency, and diurnal ingestive behavior of lactating Holstein × Gyr cows in an intensive tropical grazing system. The replacement of SBM with PM is recommended since the latter promotes the best results in terms of milk fat content.

Occurrence features of Intermediate Descending Layers [IL] over the equatorial location of Thiruvananthapuram

A study has been carried out on the various aspects of occurrence of Intermediate Descending Layers [IL] on the bottom side of the F region over the magnetic equatorial location of Thiruvananthapuram [8.5 0 N; 77 0 E; dip lat of 0.5 0 N] in India for the period from 2000−2008 using ionosonde observations. Diurnally, the IL occurrence exhibits a double peak pattern with maximum occurrence in the post noon [15–17 IST], followed by early morning [7–9 IST]. The IL has a solsticial maximum [both summer and winter] probability of occurrence [∼70% during 2006 and 20% during 2002] with minima during equinoxes [∼10% during 2002 and 40% during 2006]. The solar cycle variability of IL is brought out in the present study using data from solar cycle 23. The occurrence is found to be high during solar minimum period [70%] and low during solar maximum period [10%]. The diurnal and seasonal behaviour of IL parameters like the peak frequency and the base height are also reported in this study. The role of gravity waves in determining the above stated features of occurrence is being proposed.

Melanopsin elevates locomotor activity during the wake state of the diurnal zebrafish

Mammalian and fish pineals play a key role in adapting behaviour to the ambient light conditions through the release of melatonin. In mice, light inhibits nocturnal locomotor activity via the non‐visual photoreceptor Melanopsin. In contrast to the extensively studied function of Melanopsin in the indirect regulation of the rodent pineal, its role in the intrinsically photosensitive zebrafish pineal has not been elucidated. Therefore, it is not evident if the light signalling mechanism is conserved between distant vertebrates, and how Melanopsin could affect diurnal behaviour. A double knockout of melanopsins (opn4.1‐opn4xb) was generated in the diurnal zebrafish, which manifests attenuated locomotor activity during the wake state. Transcriptome sequencing gave insight into pathways downstream of Melanopsin, implying that sustained repression of the melatonin pathway is required to elevate locomotor activity during the diurnal wake state. Moreover, we show that light induces locomotor activity during the diurnal wake state in an intensity‐dependent manner. These observations suggest a common Melanopsin‐driven mechanism between zebrafish and mammals, while the diurnal and nocturnal chronotypes are inversely regulated downstream of melatonin.

Hospital sewage treatment facilities witness the fighting against the COVID-19 pandemic

Real-time evaluation of the fighting activities during a sudden unknown disaster like the COVID-19 pandemic is a critical challenge for control. This study demonstrates that the temporal variations of effluents from hospital sewage treatment facilities can be used as an effective indicator for such evaluation. Taking a typical infection-suffering city in China as an example, we found that there was an obvious decrease in effluent ammonia and COD concentrations in line with the start of city lockdown, and its temporal variations well indicated the major events happened during the pandemic control. Notably, the lagging period between the change point of effluent residual chlorine and the change points of COD and ammonia concentration coincided with a period in which there was a deficiency in local medical resources. In addition, the diurnal behavior of effluents from designated hospitals has varied significantly at different stages of the pandemic development. The effluent ammonia peaks shifted from daytime to nighttime after the outbreak of the COVID-19 pandemic, suggesting a high workload of the designated hospitals in fighting the rapidly emerging pandemic. This work well demonstrates the necessary for data integration at the wastewater–medical service nexus and highlights an unusual role of the effluents from hospital sewage treatment facilities in revealing the status of fighting the pandemic, which helps to control the pandemic.

Investigating Short-Period Lake-Generated Microseisms Using a Broadband Array of Onshore and Lake-Bottom Seismometers

Abstract Recent analyses of ambient seismic noise proximal to large lakes identify excitations between periods of 0.5 and 5 s as lake-generated microseisms, though the mechanisms producing them remain unclear in the absence of distinct spectral peaks. We present a unique data set combining onshore and offshore seismometers to investigate the dominant parameters controlling water-to-solid-earth seismic coupling in a lacustrine environment. Using a set of broadband observations that include six lake-bottom seismometers, we compare signals collected both within and around Lake Malawi (Nyasa) in southeastern Africa, the fifth largest freshwater lake in the world. We document clear evidence for two peaks within the lake microseism band, with pervasive diurnal excitations between periods of ∼0.6–1.3 and ∼1.3–3 s. Variations in spectral behavior as a function of recording depth and proximity to both steep lake-floor slopes and the shoreline suggest that the spectral bands may correspond to single- and double-frequency generation processes, akin to primary and secondary ocean microseisms generated by the shoaling of wind-driven gravity waves along shorelines and wave interactions within the open body of water, respectively. However, both the absolute amplitudes and temporal evolution we observe in these two bands are complex and often inconsistent with traditional microseism theory. Therefore, these spectral bands may alternatively result from complex wave–wave interaction at the lake surface within the enclosed northern end of the lake. The diurnal behavior of lake microseisms, as well as their polarizations, suggest that the wave energy is driven by a combination of seasonally varying nighttime winds funneled by lakeshore topography and waveguide effects. This work also provides a glimpse into seasonal variation in lacustrine ambient seismic noise and thus also into lake processes.

Diurnal shift of mouse activity by the deficiency of an ageing-related gene Lmna.

Nuclear lamina is a fundamental structure of the cell nucleus and regulates a wide range of molecular pathways. Defects of components of the nuclear lamina cause ageing-like physiological disorders, called laminopathy. Generally, ageing and diseases are often associated with perturbation of various time-of-day-dependent regulations, but it remains elusive whether laminopathy induces any changes of the circadian clock and physiological rhythms. Here, we demonstrated that deficiency of Lmna gene in mice caused an obvious shift of locomotor activities to the daytime. The abnormal activity profile was accompanied by a remarkable change in phase angle between the central clock in the suprachiasmatic nucleus (SCN) and the lung peripheral clocks, leaving the phase of the SCN clock unaffected by the mutation. These observations suggest that Lmna deficiency causes a change of the habitat from nocturnal to diurnal behaviours. On the other hand, molecular oscillation and its phase resetting mechanism were intact in both the Lmna-deficient cells and progeria-mimicking cells. Intriguingly, high-fat diet feeding extended the short lifespan and ameliorated the abnormalities of the behaviours and the phase of the peripheral clock in the Lmna-deficient mice. The present study supports the important contribution of the energy conditions to a shift between the diurnal and nocturnal activities.