Application of linear splines to simulate daily changes in insolation

2020 ◽  
pp. 42-49
Author(s):  
Rudolf P. Trenkenshu ◽  
Alexander S. Lelekov ◽  
Anatoliy A. Chekushkin
Keyword(s):  
Linear Equations ◽  
Early Morning ◽  
Time Of Day ◽  
Linear Increase ◽  
Day Length ◽  
Maximum Height ◽  
Microalgae Culture ◽  
Late Evening ◽  
Linear Splines ◽  
Sunlight Intensity

The paper shows the possibility of using linear splines in modeling the daily change in solar radiation. The calculations were based on the generally accepted cosine expression used for modeling insolation changes on the surface of lakes and the ocean. The equation parameters are set for the conditions of Sevastopol (44°35'N, 33°30' E): the maximum height of the sun above the horizon is about 68 degrees, the day length is 15 hours. The model curve was divided into three sections. For the early morning hours and late evening, the sunlight intensity is low and is below the “compensation point” of photosynthesis. So these areas were not considered during modeling. Three sites: the increase in irradiation from 6 to 12 hours, the maximum irradiation from 12 to 14 hours, and the decrease in irradiation from 14 to 20 hours are described by linear equations. It is shown that the deviations in the description of the data of the dependence of the sunlight intensity on the time of day by linear splines from the generally accepted formula in the form of a cosine do not exceed 5%. An example of experimental data of linear growth of productivity of A. platensis culture is given. Based on the assumption that the growth rate of microalgae culture is proportional to the amount of energy absorbed, the linear increase in productivity can be explained by a linear increase in the intensity of sunlight.

Effectiveness of Bentazon Applied at Various Times of the Day

Weed Science ◽  
1976 ◽  
Vol 24 (6) ◽  
pp. 567-570 ◽  
Author(s):  
David L. Doran ◽  
Robert N. Andersen
Keyword(s):  
Glycine Max ◽  
Practical Importance ◽  
Field Studies ◽  
Early Morning ◽  
Time Of Day ◽  
Abutilon Theophrasti ◽  
Growth Chamber ◽  
Poor Control ◽  
Late Evening

Bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-(4) 3H-one 2, 2-dioxide] was applied postemergence to common cocklebur (Xanthium pensylvanicumWallr.) and velvetleaf (Abutilon theophrastiMedic.) at various times of the day in growth chamber and field studies and to soybeans [Glycine max(L.) Merr.] in field studies. Soybeans were tolerant of bentazon regardless of time of day when treated. Results with common cocklebur and velvetleaf suggest that the time of day when bentazon is applied can be of practical importance. Poor control might occur following application in late evening, night, or early morning.

The Preferences Scale: Multinational Assessment of a New Measure of Morningness

1993 ◽  
Vol 37 (13) ◽  
pp. 925-929 ◽  
Author(s):  
Carlla S. Smith ◽  
Simon Folkard ◽  
Robert A. Schmieder ◽  
Luis F. Parra ◽  
Evelien Spelten ◽  
...  
Keyword(s):  
Early Morning ◽  
Time Of Day ◽  
Self Report ◽  
Psychometric Assessment ◽  
Total N ◽  
Circadian Time ◽  
Validity Measures ◽  
Late Evening ◽  
Mean Differences ◽  
Biological Differences

Several self-report scales have been developed to measure morningness, or the preference for early morning or late evening activity (i.e., larks vs. owls). This individual difference in human circadian (time-of-day) rhythms has applications in the selection and placement of shiftworkers for night work in industry. Researchers have recently questioned the suitability of existing scales for people with alternate sleep-wake schedules and lifestyles. These factors may also render existing scales inappropriate for use in some cultures. To address this deficiency, we developed a new morningness scale (the preferences scale) that is not yoked to specific times of the 24-hour day and has a simplified response format. Data on the preferences scale were collected from university students (total N=1,212) in four countries (U.S., England, Holland, and Spain). Responses on external validity measures (self-rated alertness over the waking day and actual and preferred arise and bed times) and another morningness scale (for comparative purposes) were also collected. Although scale statistics (aggregate and by country) suggest that the psychometric properties of the preferences scale were adequate, scale mean differences existed across countries. These results may indicate cultural, as well as the established biological, differences in morningness. However, a more thorough psychometric assessment is needed to substantiate this possibility.

The Effect of Time of Day on the Activity of Postemergence Soybean Herbicides

2013 ◽  
Vol 27 (4) ◽  
pp. 690-695 ◽  
Author(s):  
Gregory J. Stopps ◽  
Robert E. Nurse ◽  
Peter H. Sikkema
Keyword(s):  
Weed Control ◽  
Yield Loss ◽  
Early Morning ◽  
Field Trials ◽  
Time Of Day ◽  
Weed Species ◽  
Time Of Application ◽  
Late Evening ◽  
Chlorimuron Ethyl ◽  
Herbicide Activity

The effect of time of day (TOD) on the activity of six common POST herbicides was investigated in field trials from 2007 to 2009 at two locations in southwestern Ontario. Percentage weed control was assessed following application of bentazon, chlorimuron-ethyl, fomesafen, glyphosate, imazethapyr, or quizalofop-p-ethyl applied at 3-h intervals from 6:00 A.M. to midnight, when weeds averaged 15 cm tall. The effect of time of day varied with weed species, but weed control was generally reduced when herbicides were applied at 6:00 A.M., 9:00 P.M., and midnight. Herbicide activity on velvetleaf was most frequently reduced, especially for chlorimuron-ethyl, glyphosate, and imazethapyr. Control of common ragweed with glyphosate and imazethapyr was also affected by the timing of application, and pigweed species only showed an effect with glyphosate. Variation in temperature, relative humidity, and dew presence/absence at different times of the day, as well as morphological/physiological characteristics such as weed size at time of application and diurnal leaf movement in response to light intensity, may account for the variation in weed control at different times of the day. Significant soybean yield loss was not observed in this study, but may occur if herbicide efficacy is severely reduced by application at inappropriate times of day. These results provide valuable information for growers, and suggest that POST herbicides are most effective when applied midday, rather than in the early morning or late evening.

Thermoregulatory responses to cold water at different times of day

1999 ◽  
Vol 87 (1) ◽  
pp. 243-246 ◽  
Author(s):  
John W. Castellani ◽  
Andrew J. Young ◽  
James E. Kain ◽  
Michael N. Sawka
Keyword(s):  
Cold Water ◽  
Water Immersion ◽  
Early Morning ◽  
Cold Water Immersion ◽  
Time Of Day ◽  
Mean Skin Temperature ◽  
Mean Body Temperature ◽  
Metabolic Heat ◽  
Body Temperature Change ◽  
The Mean

This study examined how time of day affects thermoregulation during cold-water immersion (CWI). It was hypothesized that the shivering and vasoconstrictor responses to CWI would differ at 0700 vs. 1500 because of lower initial core temperatures (Tcore) at 0700. Nine men were immersed (20°C, 2 h) at 0700 and 1500 on 2 days. No differences ( P > 0.05) between times were observed for metabolic heat production (M˙, 150 W ⋅ m−2), heat flow (250 W ⋅ m−2), mean skin temperature (T sk, 21°C), and the mean body temperature-change in M˙(ΔM˙) relationship. Rectal temperature (Tre) was higher ( P < 0.05) before (Δ = 0.4°C) and throughout CWI during 1500. The change in Tre was greater ( P < 0.05) at 1500 (−1.4°C) vs. 0700 (−1.2°C), likely because of the higher Tre-T skgradient (0.3°C) at 1500. These data indicate that shivering and vasoconstriction are not affected by time of day. These observations raise the possibility that CWI may increase the risk of hypothermia in the early morning because of a lower initial Tcore.

scholarly journals Spatiotemporal Dynamics of the Kinetic Energy in the Atmospheric Boundary Layer from Minisodar Measurements

Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 421
Author(s):  
Alexander Potekaev ◽  
Liudmila Shamanaeva ◽  
Valentina Kulagina
Keyword(s):  
Boundary Layer ◽  
Kinetic Energy ◽  
Atmospheric Boundary Layer ◽  
Turbulent Kinetic Energy ◽  
Time Of Day ◽  
Linear Increase ◽  
Spatiotemporal Dynamics ◽  
Intermediate Layers ◽  
Subsequent Decrease ◽  
Stable Atmospheric Boundary Layer

Spatiotemporal dynamics of the atmospheric kinetic energy and its components caused by the ordered and turbulent motions of air masses are estimated from minisodar measurements of three velocity vector components and their variances within the lowest 5–200 m layer of the atmosphere, with a particular emphasis on the turbulent kinetic energy. The layered structure of the total atmospheric kinetic energy has been established. From the diurnal hourly dynamics of the altitude profiles of the turbulent kinetic energy (TKE) retrieved from minisodar data, four layers are established by the character of the altitude TKE dependence, namely, the near-ground layer, the surface layer, the layer with a linear TKE increase, and the transitive layer above. In the first layer, the most significant changes of the TKE were observed in the evening hours. In the second layer, no significant changes in the TKE values were observed. A linear increase in the TKE values with altitude was observed in the third layer. In the fourth layer, the TKE slightly increased with altitude and exhibited variations during the entire observation period. The altitudes of the upper boundaries of these layers depended on the time of day. The MKE values were much less than the corresponding TKE values, they did not exceed 50 m2/s2. From two to four MKE layers were distinguished based on the character of its altitude dependence. The two-layer structures were observed in the evening and at night (under conditions of the stable atmospheric boundary layer). In the morning and daytime, the four-layer MKE structures with intermediate layers of linear increase and subsequent decrease in the MKE values were observed. Our estimates demonstrated that the TKE contribution to the total atmospheric kinetic energy considerably (by a factor of 2.5–3) exceeded the corresponding MKE contribution.

598 Temperature profiles of sunlight-exposed surfaces in a desert climate: Determining the risks for pavement burns.

2021 ◽  
Vol 42 (Supplement_1) ◽  
pp. S150-S151
Author(s):  
Paul J Chestovich ◽  
Richard Z Saroukhanoff ◽  
Syed F Saquib ◽  
Joseph T Carroll ◽  
Carmen E Flores ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Solar Irradiance ◽  
Time Of Day ◽  
Temperature Measurements ◽  
Solar Irradiation ◽  
Porous Rock ◽  
Solid Materials ◽  
Contour Plots ◽  
Desert Climate ◽  
Sunlight Intensity

Abstract Introduction In the desert climates of the United States, plentiful sunlight and high summer temperatures cause significant burn injuries from hot pavement and other surfaces. Although it is well known that surfaces reach temperatures sufficient to cause full-thickness burns, the peak temperature, time of day, and highest risk materials is not well described. This work measured continuous temperature measurements of six materials in a desert climate over a five-month period. Methods Six different solid materials common in an urban environment were utilized for measurement. Asphalt, brick, concrete, sand, porous rock, and galvanized metal were equipped with thermocouples attached to a data acquisition module. All solid materials except metal were placed in a 2’x2’x3.5” form, and identical samples were placed in both shade and direct sunlight. Ambient temperature was recorded, and sunlight intensity was measured using a pyranometer. Measurement time interval was set at three minutes. A computational fluid dynamics (CFD) model was created using Star CCM+ to validate the data. Contour plots of temperature, solar irradiance, and time of day were created using MiniTab for all surfaces tested. Results 75,000 temperature measurements were obtained from March through August 2020. Maximum recorded temperatures for sunlight-exposed samples of porous rock was 170 F, asphalt 166 F, brick 152 F, concrete 144 F, metal 144 F, and sand 143 F. Peak temperatures were recorded on August 6, 2020 at 2:10 pm, when ambient temperature was 120 F and sunlight intensity 940 W/m2 (Table). Temperatures ranged from 36 F - 56 F higher than identical materials in the shade at the same time. The highest daily temperatures were achieved between 2:00 pm to 4:00 pm due to maximum solar irradiance. Contour plots of surface temperature as function of solar irradiation and time of day were created for all surfaces tested. Nearly identical results obtained from the CFD models to the experimentally collected data, which validated the experimental data. Conclusions Surfaces exposed to direct, continuous sunlight in a desert climate achieve temperatures from 143 F to 170 F in the early afternoon and are high enough to cause significant injury with sufficient exposure. Porous rock reached the highest temperature, followed closely by asphalt. This information is useful to inform the public of the dangers of exposed surfaces in a desert climate.

Intra- and inter-day variability in plasma tCO2 concentration in sedentary horses

2014 ◽  
Vol 10 (1) ◽  
pp. 39-47
Author(s):  
B.E. Bergstrom ◽  
J.H. Foreman ◽  
C.R. Foreman ◽  
A.M. Barger
Keyword(s):  
Blood Test ◽  
Indoor Environment ◽  
Early Morning ◽  
Time Of Day ◽  
Individual Variability ◽  
Strong Ion Difference ◽  
Serum Chemistry ◽  
Blood Samples ◽  
Early Afternoon ◽  
Glass Tubes

Sodium bicarbonate and other alkalinising solutions (‘milkshakes’) have been given to horses surreptitiously before exercise to provide exogenous buffering effects. After an initial positive blood test, some accused horse trainers claim that their horses ‘naturally test high’, so some jurisdictions allow a secured quarantine in which the horse is tested multiple times. The objective of this experiment was to determine the intra- and inter-day variability of plasma total CO2 (tCO2) and other plasma strong ions in a group of sedentary horses housed similarly to a quarantine period. The hypothesis was that plasma tCO2 would not remain constant over a multi-day monitoring interval, but would vary measurably during that interval. Eight sedentary (unconditioned) horses were studied for 2 weeks. Horses were acclimated to a climate-controlled indoor environment and an alfalfa-only diet for a minimum of 10 days prior to sampling. Horses were sampled 3 times daily for 5 consecutive days at 7:00, 11:00 and 15:00 h. Blood samples were collected directly into 10 ml heparinised evacuated glass tubes by jugular venipuncture using a double-ended 0.91 mm needle. Samples were chilled until concentrations of plasma tCO2, Na+, K+, and Cl-, were determined within 1-3 h of sampling using an automated serum chemistry analyzer which was calibrated daily using commercial reagents obtained from the manufacturer as well as externally-obtained NIST-traceable calibrating solutions. Mean results documented mild variations in mean plasma tCO2 (range 28.9-31.6 mmol/l), but individual horses’ plasma tCO2 ranged over 4-7 units. Results showed that there was considerable intra- and inter-individual variability in plasma tCO2. Mean pooled tCO2 and measured strong ion difference (SIDm) differed by time-of-day, with both late morning and early afternoon values lower than early morning values (P<0.001). There was a strong positive linear relationship between plasma SIDm and tCO2 (r=0.75, P<0.001).

scholarly journals Protein Supplementation and Grazing Behavior for Cows on Differing Late-Season Rangeland Grazing Systems

Animals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 3219
Author(s):  
James E. Sprinkle ◽  
Joseph K. Sagers ◽  
John B. Hall ◽  
Melinda J. Ellison ◽  
Joel V. Yelich ◽  
...  
Keyword(s):  
Early Morning ◽  
Protein Supplementation ◽  
Grazing Behavior ◽  
Late Season ◽  
Bite Rate ◽  
Measured Time ◽  
Late Evening ◽  
Grazing Systems ◽  
Time Periods ◽  
Walking Time

The objective was to determine if low- or high-residual feed intake (LRFI or HRFI, n = 24 for each) Hereford × Angus cows on continuously or rotationally grazed rangeland altered their grazing behavior when provided a protein supplement in late autumn. Treatments included continuously grazed, control (CCON, n = 12); continuously grazed, supplemented (CTRT, n = 12); rotationally grazed, control (RCON, n = 12); and rotationally grazed, supplemented pastures (RTRT, n = 12). Cows in each treatment had grazing time (GT), resting time (RT), and walking time (WLK) measured for 2 years with accelerometers. Bite rate (BR) was also measured. Time distributions of GT and RT differed by year (p < 0.05), being influenced by colder temperatures in 2016. Cattle in 2016 spent more time grazing during early morning and late evening (p < 0.05) and rested more during the day (p < 0.05). In 2017, cattle in the CCON treatment walked more (p < 0.05) during early morning time periods than did the CTRT cattle, indicative of search grazing. All supplemented cattle had greater BR (p < 0.05) than control cattle in 2017. Cattle with increased nutritional demands alter grazing behavior in a compensatory fashion when grazing late-season rangelands.

scholarly journals Life near a city: activity pattern of Golden Jackal Canis aureus Linnaeus, 1758 (Mammalia: Carnivora: Canidae) in a habitat adjoining Bhubaneswar, India

2021 ◽  
Vol 13 (9) ◽  
pp. 19363-19366
Author(s):  
Subrat Debata
Keyword(s):  
Activity Pattern ◽  
Prey Species ◽  
Early Morning ◽  
Golden Jackal ◽  
Eastern India ◽  
Present Study Area ◽  
Late Evening ◽  
Reduced Activity ◽  
Second Peak ◽  
Intense Heat

Activity pattern of the Golden Jackal was studied by camera trapping survey in an urban influenced protected habitat in Odisha, eastern India from January to April 2019. A total of 552 independent photos of Golden Jackals were obtained from 771 trap nights. Although Golden Jackals were active throughout the day, they showed two major peaks in activity; the first peak during late evening after sunset, and the second peak during early morning until sunrise. The reduced activity of Golden Jackal during day time in the present study area might be due to less movement of prey species, intense heat, and heavy human traffic.

Correlation of Chronotype (Lark Versus Night Owl Status) with Mind-Set and Effect of Chronotype on Examination Performance in Veterinary School

2021 ◽  
pp. e20210033
Author(s):  
Margaret V. Root Kustritz ◽  
Hannah J. Bakke ◽  
Aaron Rendahl
Keyword(s):  
Academic Success ◽  
Student Performance ◽  
Early Morning ◽  
Time Of Day ◽  
Start Time ◽  
Personal Management ◽  
Main Effect ◽  
Veterinary School ◽  
Mind Set ◽  
The Relationship

Chronotype describes what time of day people are most productive, with the specific terminology of larks (productive early in the day) and night owls (productive late in the day). Society, including education, schedules work at times that generally favor larks. The goals of this study were to (a) define our student population regarding mind-set and chronotype, (b) examine the relationship between chronotype and mind-set score, and (c) examine the relationship between lark score and examination score with examinations offered at varying times of day. The null hypotheses were that there would be no relationships between these variables. If the hypotheses were not proven, this information would be used to educate students about personal management to optimize academic success and to help the college determine if scheduling or other variations in examination implementation could be altered to permit students to demonstrate best their knowledge and skills. There were 184 participants from the classes of 2020–2022. Overall, there were few definite night owls or larks, with 55% of participants categorized as neither. Overall, 78% of students had either a strong growth mind-set or a growth mind-set with some fixed ideas. No meaningful association between chronotype and mind-set score was observed. There was neither a significant main effect for chronotype nor a significant interaction with start time for examinations. Scheduling of examinations in the early morning did not negatively impact student performance based on chronotype in this study.

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