Time Of Sunrise Research Articles

International Comparison of the Levels and Potential Correlates of Objectively Measured Sedentary Time and Physical Activity among Three-to-Four-Year-Old Children.

Physical activity (PA) patterns track from childhood through to adulthood. The study aimed to determine the levels and correlates of sedentary time (ST), total PA (TPA), and moderate-to-vigorous PA (MVPA) in preschool-aged children. We conducted cross-sectional analyses of 1052 children aged three-to-four-years-old from six studies included in the International Children’s Accelerometry Database. Multilevel linear regression models adjusting for age, gender, season, minutes of wear time, and study clustering effects were used to estimate associations between age, gender, country, season, ethnicity, parental education, day of the week, time of sunrise, time of sunset, and hours of daylight and the daily minutes spent in ST, TPA, and MVPA. Across the UK, Switzerland, Belgium, and the USA, children in our analysis sample spent 490 min in ST per day and 30.0% and 21.2% of children did not engage in recommended daily TPA (≥180 min) and MVPA (≥60 min) guidelines. There was evidence for an association between all 10 potential correlates analyzed and at least one of the outcome variables; average daily minutes spent in ST, TPA and/or MVPA. These correlates can inform the design of public health interventions internationally to decrease ST and increase PA in preschoolers.

The Effect of Ozone Shadowing on the D Region Ionosphere During Sunrise

AbstractDiurnal very low frequency subionospheric radio wave phase measurements show a night‐to‐day transition pattern. During this sunrise transition a phase perturbation, which consist of a phase overshoot followed by a small phase recovery to normal daytime values, is often observed. The variability of the size of this sunrise phase perturbation and its maximum and end times were monitored to identify the associated physical causes. Very low frequency signal from the 22.1‐kHz UK transmitter (call sign GVT) recorded at Sodankylä, Finland, from 20 April 2010 to 31 December 2016 were used. The timing at the maximum of the phase perturbation period has an annual pattern that is well described by the seasonal variation of the sunrise time 28 km above the transmitter. Variations in ozone number density at 38–42‐km altitudes are better correlated (R = 0.7) with the sunrise phase perturbation variability than at any other altitudes below ~80 km, and exhibit higher correlation values than for atmospheric temperature. Our results show that the main characteristics of the observed very low frequency sunrise phase perturbation arise from shadowing of short‐wavelength solar UV flux from the D region ionosphere due to stratospheric ozone absorption.

Vertical fine structure and time evolution of plasma irregularities in the Es layer observed by a high-resolution Ca+ lidar

The vertical fine structures and the time evolution of plasma irregularities in the sporadic E (Es) layer were observed via calcium ion (Ca+) density measurements using a resonance scattering lidar with a high time-height resolution (5 s and 15 m) at Tachikawa (35.7°N, 139.4°E) on December 24, 2014. The observation successfully provided clearer fine structures of plasma irregularities, such as quasi-sinusoidal height variation, localized clumps, “cats-eye” structures, and twist structures, in the sporadic Ca+ ({{text{Ca}}^{+}}_{text{s}}) layers at around 100 km altitude. These fine structures suggested that the Kelvin–Helmholtz instabilities occurred in the neutral atmosphere whose density changed temporarily or spatially. The maximum Ca+ density in the {{text{Ca}}^{+}}_{text{s}} layer was two orders of magnitude smaller than the maximum electron density estimated from the critical frequency (foEs) simultaneously observed by the ionosonde at Kokubunji (35.7°N, 139.5°E). A strong positive correlation with a coefficient of 0.91 suggests that Ca+ contributes forming the Es layer as well as major metallic ions Fe+ and Mg+ in the lower thermosphere. Moreover, the formation of a new {{text{Ca}}^{+}}_{text{s}} layer at 110 km and the upward motions of the {{text{Ca}}^{+}}_{text{s}} layers at 100 km and 110 km were observed before the local sunrise and just after the sunrise time at the conjugation point. Although the presence or absence of a causal relationship with the sunrise time was not clear, a possible explanation for the formation and the upward motions of the {{text{Ca}}^{+}}_{text{s}} layers was the occurrence of strong horizontal wind, rather than the enhancement of the eastward electric field.

Diel patterns of movement activity and habitat use by leopards (Panthera pardus pardus) living in a human-dominated landscape in central Kenya

Large carnivores can exert strong influence on local ecosystems, making them important targets for biodiversity conservation. An important question for conserving large carnivores outside of protected areas is the role of human activity in influencing the behavior of these predators. We used high-resolution animal location tracking and statistical modeling to examine the behavior of seven leopards (Panthera pardus) occupying an area that includes a research center and livestock ranch in central Kenya. Our analyses reveal changes in habitat selection around the times of sunrise and sunset, corresponding with changes in human activity at our site. Activity patterns were also variable within and among the leopards in our sample. To explore sources of this variability, we used regression modeling to estimate the relative influence of changing spatial and environmental conditions for leopard ranging behavior. Despite the tendency to be active during the day, we found that leopards strongly avoided areas where they were likely to encounter people during the daytime and showed variable selection for these same areas at night. The use of anthropogenic habitats was also associated with periods of greater ranging activity. We discuss the implications of these results for conservation efforts that attempt to balance the demands of livestock ranching alongside carnivore conservation.

Where in the world? Latitude, longitude and season contribute to the complex co-ordinates determining cortisol levels.

Cortisol is a critical stress hormone with circadian rhythms synchronized by light. There are seasonal differences in expression of pro-inflammatory genes and in some diseases moderated by glucocorticoids. As light changes with season and with latitude and longitude, we assessed changes in population cortisol associated with these parameters. Retrospective data audit. Populations across 4 states of Australia over 3years. Serum cortisol levels, age, gender, time of collection, sunrise time, season and location were determined. In 4 geographically separate populations (n=84937), sunrise time and time of sample collection were the most important factors influencing median cortisol. Over 2hours in the morning cortisol could decrease by up to 76nmol/L, and for each hour that sunrise time advanced there was up to 6.9% increase in cortisol. A cyclic seasonal pattern of cortisol was confirmed each year in all populations with autumn/winter cortisol highest compared to spring/summer with differences of up to 44nmol/L. There was less change in cortisol in latitudes closer to the equator but cortisol progressively increased from 25 to 30°S of the equator. In more southerly latitudes, seasonal cortisol variation also increased, and over the entire latitude range, there was up to 50nmol/L change in cortisol. Longitude variation within a time zone had a minimal effect on median cortisol. Location, time of year and time of day are important influences on population cortisol levels. Elevated autumn/winter morning cortisol levels are likely due to sampling closer to the circadian peak due to later sunrise time. Understanding how the environment can influence cortisol levels may further our knowledge of physiology and disease.

Robust Broadband Maritime Communications: Theoretical and Experimental Validation

AbstractAtmospheric ducts, which are caused by the rapid decrease in the refractive index of the lower atmosphere, have been recognized as the dominant propagation mechanism for long range maritime links. Recent advances in radio technology are making reliable high‐capacity overwater links a reality. A ray‐tracing simulation model was developed to obtain reliable prediction of maritime link performance beyond 30 km for realistic conditions. A series of static and mobile long range maritime multiple‐input multiple‐output links were tested with representative antenna heights at 1.39 (Band 3 or L‐Band) and 4.5 GHz (Band 4 or C‐Band) during periods with various levels of ducting activities, for example, sunset and sunrise times. Measured link performance and observed ducting occurrences are compared to predictions to validate the model ability to accurately predict and explain link performance for various ducting conditions. The test results agree with the model predictions and illustrate the various Received Signal Level degradation, enhancement, and fluctuations that can be expected in long range maritime links below 6 GHz. We also report on short‐term (few to several minutes) fluctuations of the received signal level at the two measurement frequency bands during high ducting activity periods. Measurements and theoretical analysis of the effect of ducting on the quality of maritime communication links indicate that both reflection‐induced and ducting‐induced disruptions are different and more frequent in higher‐frequency bands. This work opens interesting perspectives on providing more robust and more predictable communications in the presence of ducting.

The Study of Solar Incident on Planar Surface for Kinetic Art

In future, renewable energy will become mainstream global energy source because it flows all the time, also the solar energy. The sun always directly emits light through the earth, depending on how we utilize it. The study will fill the gap that the most of photovoltaic panel facing to the same direction against solar incident for maximum efficiently. It would be better if photovoltaic appliance to have aesthetic and capability in the same time. But changing planar surface angle for artistic purpose also need to consideration of efficiency for solar energy. The purpose of this study is to explore the most appropriate angle of solar incident that impacts directly to the planar surface, which will leads to gain maximum electric energy from photovoltaic cell. The variation angle of planar surfaces will be discovered could possibly produce energy to be applied for any purposes. The additional sources of other renewable energy gadgets may install to generate more electric power. These planar surfaces can be composited together into many new shapes and forms for researcher to create more impressive artwork. In this study, the chosen material was Monocrystalline solar cell (mono-Si) to generate energy, wood and glass for kinetic sculpture. The procedures of study were as follow: 1. Specific location by Latitude will be achieved I. Altitude II. Seasons III. Sunlight direction IV. Sunrise and Sunset time 2. Calculate Solar radiation from each Photovoltaic cell for energy gain. 3. Compares output energy and mechanic usage for Kinetic Art 4. Increases capability of solar incident by improving angle of planar surface or multiply. Results of this research will be the search of artistic identity in art forms, it will be guideline for designers to develop potential Kinetic arts and or further creative works.

HMMoce: An R package for improved geolocation of archival‐tagged fishes using a hidden Markov method

Abstract Electronic tagging of marine fishes is commonly achieved with archival tags that rely on light levels and sea surface temperatures to retrospectively estimate movements. However, methodological issues associated with light‐level geolocation have constrained meaningful inference to species where it is possible to accurately estimate time of sunrise and sunset. Most studies have largely ignored the oceanographic profiles collected by the tag as a potential way to refine light‐level geolocation estimates. Open‐source oceanographic measurements and outputs from high‐resolution models are increasingly available and accessible. Temperature and depth profiles recorded by electronic tags can be integrated with these empirical data and model outputs to construct likelihoods and improve geolocation estimates. The R package HMMoce leverages available tag and oceanographic data to improve position estimates derived from electronic tags using a hidden Markov approach. We illustrate the use of the model and test its performance using example blue and mako shark archival tag data. Model results were validated using independent, known tracks and compared to results from other geolocation approaches. HMMoce exhibited as much as six‐fold improvement in pointwise error as compared to traditional light‐level geolocation approaches. The results demonstrated the general applicability of HMMoce to marine animals, particularly those that do not frequent surface waters during crepuscular periods.

The influence of time factors on the dynamics of roe deer collisions with vehicles

Environmentalists and authorities responsible for road safety are trying to reduce the number of wildlife collisions with vehicles (WCV) worldwide. Roe deer are the most common large animal involved in WCV in Europe. This article discusses the distribution of 2010 wildlife-vehicle collisions involving roe deer (WVRD) in Lithuania in 2013 and 2014. The collisions were analyzed in terms of monthly and daily data for each month separately, and the results are compared with the time of sunrise and sunset in Lithuania. By analyzing trends of natural factors that influence the number of collisions we show that the frequency of WVRD is strongly correlated with seasonal and yearly changes in sunrise and sunset. This research shows that these natural factors are extremely important for the dynamics of WVRD. Future analysis of these factors and application of appropriate preventative measures should significantly reduce the risk of collision between vehicles and roe deer.

Drombeg Stone Circle, Ireland, analyzed with respect to sunrises and lithic shadow-casting for the eight traditional agricultural festival dates and further validated by photography

A new survey of Drombeg Stone Circle and accurate analysis of shadow effects beginning at particular sunrises of the calendar year has led to a breakthrough in the understanding of lithic symbolism and the intentions behind the construction of this and other Irish monuments including Knowth and Newgrange that also have astronomical alignments. 
 At Drombeg specific standing stones play critical roles at sunrise for all eight of the festival dates as known traditionally and historically for agricultural communities and as now inferred for prehistoric times following the present observation-based analysis.
 Crucial for Drombeg in the summer half of the year is the positioning of a tall straight-sided portal stone such that its shadow at midsummer sunrise encounters an engraving on the recumbent stone diametrically opposite. During subsequent minutes the shadow moves away allowing the light of the sun to fall on the carved symbol. It is the same for sunrises at Beltane (May Day), Lughnasadh (Lammas), and the equinoxes when shadows from other perimeter stones achieve the same coupling with the same image, each time soon replaced by sunlight. For the winter half of the year which includes dates for Samhain, the winter solstice and Imbolc, the target stone for shadow reception at sunrise is a huge lozenge-shaped megalith, artificially trimmed. Moreover, for 22 March and 21 September there is notable dramatic action by shadow and light between a precisely positioned narrow pillar stone and the lozenge stone.
 As a result, at sunrise at Drombeg eight calendrical shadow events have been witnessed and photographed. This attests to the precision of Neolithic planning that determined the stone positions, and demonstrates the antiquity of the calendar dates for these traditional agricultural festivals. Discussion is held as to what the concept of shadow casting between shaped or engraved stones at the time of sunrise may have meant in terms of lithic symbolism for the planners and builders. This leads to a possible explanation in terms of the ancient worldview known as the hieros gamos or the Marriage of the Gods between Sky and Earth.

Drombeg Stone Circle, Ireland, analyzed with respect to sunrises and lithic shadow-casting for the eight traditional agricultural festival dates and further validated by photography

A new survey of Drombeg Stone Circle and accurate analysis of shadow effects beginning at particular sunrises of the calendar year has led to a breakthrough in the understanding of lithic symbolism and the intentions behind the construction of this and other Irish monuments including Knowth and Newgrange that also have astronomical alignments. At Drombeg specific standing stones play critical roles at sunrise for all eight of the festival dates as known traditionally and historically for agricultural communities and as now inferred for prehistoric times following the present observation-based analysis.Crucial for Drombeg in the summer half of the year is the positioning of a tall straight-sided portal stone such that its shadow at midsummer sunrise encounters an engraving on the recumbent stone diametrically opposite. During subsequent minutes the shadow moves away allowing the light of the sun to fall on the carved symbol. It is the same for sunrises at Beltane (May Day), Lughnasadh (Lammas), and the equinoxes when shadows from other perimeter stones achieve the same coupling with the same image, each time soon replaced by sunlight. For the winter half of the year which includes dates for Samhain, the winter solstice and Imbolc, the target stone for shadow reception at sunrise is a huge lozenge-shaped megalith, artificially trimmed. Moreover, for 22 March and 21 September there is notable dramatic action by shadow and light between a precisely positioned narrow pillar stone and the lozenge stone.As a result, at sunrise at Drombeg eight calendrical shadow events have been witnessed and photographed. This attests to the precision of Neolithic planning that determined the stone positions, and demonstrates the antiquity of the calendar dates for these traditional agricultural festivals. Discussion is held as to what the concept of shadow casting between shaped or engraved stones at the time of sunrise may have meant in terms of lithic symbolism for the planners and builders. This leads to a possible explanation in terms of the ancient worldview known as the hieros gamos or the Marriage of the Gods between Sky and Earth.

Seasonal singing of a songbird living near the equator correlates with minimal changes in day length

Behaving in accordance with natural cycles is essential for survival. Birds in the temperate regions use the changes of day length to time their behavior. However, at equatorial latitudes the photoperiod remains almost constant throughout the year, and it is unclear which cues songbirds use to regulate behaviors, such as singing. Here, we investigated the timing of dawn-song of male silver-beaked tanagers in the equatorial lowland Amazonas over two years. In this region, birds experience around nine minutes of annual day length variation, with sunrise times varying by 32 minutes over the year. We show that the seasonal timing of dawn-song was highly regular between years, and was strongly correlated with slight increases in day length. During the singing season the daily dawn-song onset was precisely aligned to variations in twilight time. Thus, although photoperiodic changes near the equator are minimal, songbirds can use day length variation to time singing.

Height-dependent sunrise and sunset: Effects and implications of the varying times of occurrence for local ionospheric processes and modelling

It is well established that the sunrise and sunset periods are of particular importance to ionospheric research and modelling because of the rapid changes in the ionospheric plasma density, temperature, and dynamics. In particular, the sharp increase in the ionisation following sunrise results in a quick increase in the ionospheric peak density, NmF2, and a decrease in the peak height, hmF2. Changes in plasma temperature, scale height and transport processes add further complexity which makes it difficult to investigate and model the ionospheric behaviour during this transitional period from night to day. One of the aspects contributing to this difficulty is that not all ionospheric altitudes are exposed to the first sunlight of the day at the same time. During sunrise, the upper part of the ionosphere is illuminated prior to the lower part which is still in the dark. The boundary between sunlit and dark regions moves downwards until it reaches the surface of the Earth, which is commonly taken as the moment of sunrise at certain geographical coordinates. This means that the sunrise at surface level does not occur until after the entire ionosphere has been illuminated. During sunset, the same process happens in reverse order. This paper addresses the issue of these altitude-dependent times of sunrise and sunset and reports on our study of some of the effects on the diurnal variations in the ionospheric characteristics.

Studies of seismo-ionospheric correlations using anomalies in phase of very low frequency signal

ABSTRACTWe present the results of the statistical analysis of very low frequency (VLF) signal transmitted from NWC transmitter (latitude 21.8° S, longitude 114.15° E) at 19.8 kHz received at Ionospheric and Earthquake Research Centre (IERC) (latitude 22.50° N, longitude 87.79° E). We analyse the phase of VLF signal for the whole year 2011 and compute the sunrise and sunset terminator time from it. We observe unusual shift of these sunrise and sunset terminator time during seismic events for which the earthquake epicentres are in India and its subcontinent region. We calculate the total energy accumulation by all those earthquakes for a single day and compute the effective magnitude of all the earthquakes for that day which behaves as a single quake. We compute a cross correlation between fluctuation in terminator time shifts from the normal value with effective magnitude of earthquake. We found that the unusual fluctuations in terminator time are well correlated with earthquake magnitude and the fluctuation is maximum on two days prior to earthquake events.

Rise and Shine

We analyze the effect of school start time on academic performance. Sleep patterns are determined in part by sunrise times, which vary across time zones. Because school start times do not fully reflect this difference, we instrument for the hours of sunlight before school with the time zone boundary in Florida. We find that moving start times one hour later relative to sunrise increases test scores by 0.08 and 0.06 standard deviations for adolescents in math and reading, respectively. In math, the effect is larger for older children and co-varies with entry into an important pubertal stage. School districts can improve performance while maintaining the current distribution of start times by moving classes earlier for younger children and later for older children.

Ground-based measurements of the vertical E-field in mountainous regions and the “Austausch” effect

Past measurements of the atmospheric vertical electric field (Ez or potential gradient) at numerous land stations showed a strong response of the daily electric field to a morning local effect known as “Austausch” — the transport of electrical charges due to increased turbulence. In mountainous regions, nocturnal charge accumulation, followed by an attachment process to aerosols near the surface in valleys, known as the electrode effect, is lifted as a charged aerosol layer by anabatic (upslope) winds during the morning hours due to solar heating.Ground-based measurements during fair weather days were conducted at three mountain stations in Israel and Armenia. We present results of the mean diurnal variation of Ez and make comparisons with the well-known Carnegie curve and with past measurements of Ez on mountains. We report a good agreement between the mean diurnal curves of Ez at various mountain stations and the time of local sunrise when the Ez is found to increase. We attribute this morning maximum to the Austausch (or exchange) layer effect. We support our findings with conduction and turbulent current measurements showing high values of ions and charged aerosols being transported by winds from morning to noon local time, and by model simulations showing the convergence of winds in the early morning hours toward the mountain peak.

Seasonal ambient changes influence inpatient falls.

falls by inpatients often result in serious injuries and deterioration in a patient's physical abilities and quality of life, especially among older individuals. Although various factors have been found to be associated with falls, the combined effects of behavioural and ambient factors are not fully evaluated. we investigated the influence of both behavioural and ambient factors on inpatient falls, focusing on seasonal and diurnal variations. retrospective study. we surveyed the incident reports related to falls from April 2010 to March 2014 and examined the relationship between the incidents and seasonal and diurnal variations in behavioural and ambient factors, including the sunrise time, the night-time length and temperature. we identified 464 fallers from 3,037 incident reports. The average fall-rate of the study population was 1.4 ± 0.5/1,000 occupied bed-days. The seasonal and diurnal variations in falls were compared. The number of falls around dawn in October-February was higher than that in April-September. Toileting was the behaviour most frequently related to the falls (56.9%, n = 264), and 57.1% of the falls occurred at night. A multivariate analysis showed that the night-time length was significantly related to an increase in night-time falls (P = 0.047). these results suggested that the inpatient falls increased in the early morning from November to March and tended to be related to toileting activities. Considering these results, additional attention and support during the higher risk hours and seasons, especially in relation to toileting activities, might help to reduce the incidence of falls. N/A (Because of retrospective nature).

Latitude affects Morningness-Eveningness: evidence for the environment hypothesis based on a systematic review

Morningness-eveningness (M/E) is an individual trait related to a person’s sleep-wake cycle and preference for morning or evening hours. The “environment hypothesis” suggests that M/E is dependent on environmental factors, such as latitude, mean average temperature and photoperiod. We here analyzed a large number of datasets to assess this effect based on a systematic review. Data were from a total of 87 datasets and 35,589 individuals based on 28 countries. Partial correlations correcting for age revealed significant relationships between M/E and latitude, mean yearly temperature, photoperiod and sunset. Evening orientation was related to higher latitude, longer days and later sunset. Morning orientation was related to higher average temperatures. Percentage of females and sunrise time had no significant influence. These variables (sunset, temperature, photoperiod) were then input in a general linear model. The full model showed an influence of age and of sunset on CSM scores, but not of photoperiod and average temperature. Sunset, therefore, seems to be the most important statistical predictor for the observed latitudinal gradient.

Incorporating Influential Factors in Diurnal Temperature Estimation with Sparse Data

AbstractIn order to achieve certain research objectives, researches may have to utilize data at different levels. Temperature is one such attribute that is being collected at different levels. In many of the meteorological stations, daily temperature readings are being collected but not the hourly values. Due to the importance of hourly temperature values in many studies, many methods can be found in the literature to estimate hourly temperature reading using sparse data. Moreover, apart from daily maximum and minimum temperatures, many auxiliary variables such as sun set time, sun rise time and solar radiation values can be considered important to increase the accuracy of the estimates. This paper suggests an algorithm to incorporate influential variables when estimating hourly temperature values using sparse data. The paper also proposes a novel method “RATE” to estimate unusual temperature curves during rainy days, that have shown equal or better results when compared to LEA. However, for situations, where the rain times of the day becomes random, the RATE seems to be less accurate.

Rainfall, leafing phenology and sunrise time as potential Zeitgeber for the bimodal, dry season laying pattern of an African rain forest tit (Parus fasciiventer)

Recent studies have documented a mismatch between the phenology of leaf production, prey availability and the nestling food requirements of north temperate songbirds, attributed to climate change effects. Although tropical forest species have often been regarded as relatively aseasonal breeders, similar disruptive effects can be expected at equatorial latitudes, where comparatively little is known of the links between weather, leafing phenology, food availability and bird breeding activity, particularly in complex rain forest habitats. During a 19-year study at 1°S in Bwindi Impenetrable Forest, Uganda, Stripe-breasted Tits Parus fasciiventer showed a strongly bimodal laying pattern, breeding mainly in the two dry seasons, with 50 % of breeding activity occurring in January–February and 19 % in June–July. Individual females bred in both dry seasons, laying their first and last clutches up to 28 weeks apart. Breeding activity was linked to leaf production, which peaked mainly in November–December, following the September–November wet season. Increased leaf production is likely to have stimulated a rise in caterpillar numbers during December–February, coinciding with peak food demands by nestling tits. Laying was thus positively correlated with increased leaf production in the preceding calendar month, but was also linked to day length and a change in sunset time. To investigate possible links between egg laying and photic cues I compared the median date of first clutches laid by marked females in each half of the breeding year (October–March and April–September), with annual changes in photoperiod (varying by 7 min p.a.) and sunrise time (varying bimodally, by 31 min p.a.). The two median laying dates fell 138–139 days after the last date on which sunrise had occurred at 07:05 in August and January, suggesting the potential for sunrise time to act as a cue, or Zeitgeber, for breeding in tropical birds. Further work is required to establish whether the relationship is causative or coincidental.