INFLUENCE OF TEMPERATURE AND HUMIDITY ON THE EMERGENCE BEHAVIOUR OF ANAX JUNIUS (ODONATA: AESHNIDAE)

1973 ◽  
Vol 105 (7) ◽  
pp. 975-984 ◽  
Author(s):  
Robert Trottier

AbstractEmergence from the water of Anax junius Drury normally occurred after sunset. The onset was affected independently by water temperature and air temperature; low water temperature and high air temperature delayed the onset of emergence. In the field, the net vrtical distance travelled above the water, before ecdysis, was positively correlated with air temperature. In the laboratory, the vertical distance travelled above the water was greatest when air and water temperatures were approximately the same. The average speed of climbing to the first resting position above the water surface was faster at high than low water temperature, but the average speed of climbing from there to the final position, where ecdysis occurred, was reduced due to the effects of air temperature and humidity. Air temperatures below 12.6 °C were found to retard ecdysis and larvae returned to the water and emerged early the following day making the final process of emergence and ecdysis diurnal instead of nocturnal. The duration of ecdysis was shorter at high than low air temperatures and only the first three stages, as arbitrarily defined, were longer at low than high relative humidity; stage 4, shortened with low relative humidity. This study shows that A. Junius, emerging from the water is affected at first by the temperature experienced when submerged, but it becomes gradually and cumulatively affected by air temperature and humidity while climbing to the ecdysial position and moulting.

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1377
Author(s):  
Weifang Shi ◽  
Nan Wang ◽  
Aixuan Xin ◽  
Linglan Liu ◽  
Jiaqi Hou ◽  
...  

Mitigating high air temperatures and heat waves is vital for decreasing air pollution and protecting public health. To improve understanding of microscale urban air temperature variation, this paper performed measurements of air temperature and relative humidity in a field of Wuhan City in the afternoon of hot summer days, and used path analysis and genetic support vector regression (SVR) to quantify the independent influences of land cover and humidity on air temperature variation. The path analysis shows that most effect of the land cover is mediated through relative humidity difference, more than four times as much as the direct effect, and that the direct effect of relative humidity difference is nearly six times that of land cover, even larger than the total effect of the land cover. The SVR simulation illustrates that land cover and relative humidity independently contribute 16.3% and 83.7%, on average, to the rise of the air temperature over the land without vegetation in the study site. An alternative strategy of increasing the humidity artificially is proposed to reduce high air temperatures in urban areas. The study would provide scientific support for the regulation of the microclimate and the mitigation of the high air temperature in urban areas.


1975 ◽  
Vol 39 (1) ◽  
pp. 93-102 ◽  
Author(s):  
R. M. Smith ◽  
J. M. Hanna

Fourteen male subjects with unweighted mean skinfolds (MSF) of 10.23 mm underwent several 3-h exposures to cold water and air of similar velocities in order to compare by indirect calorimetry the rate of heat loss in water and air. Measurements of heat loss (excluding the head) at each air temperature (Ta = 25, 20, 10 degrees C) and water temperature (Tw = 29–33 degrees C) were used in a linear approximation of overall heat transfer from body core (Tre) to air or water. We found the lower critical air and water temperatures to fall as a negative linear function of MSF. The slope of these lines was not significantly different in air and water with a mean of minus 0.237 degrees C/mm MSF. Overall heat conductance was 3.34 times greater in water. However, this value was not fixed but varied as an inverse curvilinear function of MSF. Thus, equivalent water-air temperatures also varied as a function of MSF. Between limits of 100–250% of resting heat loss the followingrelationships between MSF and equivalent water-air temperatures were found (see article).


Author(s):  
Alisher Muradullaevich Muradullaev

This article presents the results of studies on the change of the water-holding ability in leaves of some varieties and lines of cotton under the influence of various high air temperatures (I control option from +24.6 to + 35.4 °C; II option - from +36.4 to +45, 1 °C; III option - from +39.5 to + 48.4 °C). At a high air temperature of + 48.4 °C, the water-holding capacity of the leaves in varieties Surkhan-14, Istiklol-14, Bukhara-102 was 26.2; 24.6; 26.4%, which indicates the relative resistance of these varieties to high air temperatures. KEYWORDS: cotton, variety, line, high air temperature, relative humidity, water holding ability.


Author(s):  
Tongxin Zhang ◽  
Dennis L. O’Neal ◽  
Stephen T. McClain

Abstract Experiments were conducted on a cold flat aluminum plate to characterize the variation of frost roughness over both time and location on the surfaces. The testing conditions included air temperatures from 8 to 16 °C, wall temperatures from −20 to −10 °C, relative humidities from 60 to 80%, and air velocities from 0.5 to 2.5 m/s. Each test lasted 2 h. A 3D photogrammetric method was employed to measure the variation in frost root-mean-square height and skewness by location and time. These data were used to develop the equivalent sand-grain roughness for the frost at different locations and time. The experimental results showed that frost roughness varied by location and changed with time. For the environmental conditions in this study, relative humidity and air temperature were the most important factors determining changes in the peak frost roughness. For example, at an air temperature of 12 °C and a surface temperature of −15 °C, the frost roughness peaked at about 40 min for a relative humidity of 80% and 90 min for a relative humidity of 60%. Empirical correlations were provided to describe the relationships between the environmental conditions and the appearance of the peak frost roughness.


Author(s):  
Josh Foster ◽  
James W. Smallcombe ◽  
Simon Hodder ◽  
Ollie Jay ◽  
Andreas D. Flouris ◽  
...  

Abstract Increasing air movement can alleviate or exacerbate occupational heat strain, but the impact is not well defined across a wide range of hot environments, with different clothing levels. Therefore, we combined a large empirical study with a physical model of human heat transfer to determine the climates where increased air movement (with electric fans) provides effective body cooling. The model allowed us to generate practical advice using a high-resolution matrix of temperature and humidity. The empirical study involved a total of 300 1-h work trials in a variety of environments (35, 40, 45, and 50 °C, with 20 up to 80% relative humidity) with and without simulated wind (3.5 vs 0.2 m∙s−1), and wearing either minimal clothing or a full body work coverall. Our data provides compelling evidence that the impact of fans is strongly determined by air temperature and humidity. When air temperature is ≥ 35 °C, fans are ineffective and potentially harmful when relative humidity is below 50%. Our simulated data also show the climates where high wind/fans are beneficial or harmful, considering heat acclimation, age, and wind speed. Using unified weather indices, the impact of air movement is well captured by the universal thermal climate index, but not by wet-bulb globe temperature and aspirated wet-bulb temperature. Overall, the data from this study can inform new guidance for major public and occupational health agencies, potentially maintaining health and productivity in a warming climate.


1959 ◽  
Vol 37 (2) ◽  
pp. 165-174
Author(s):  
R. E. Haist ◽  
Rebeka Moscarello ◽  
T. L. Friedlich ◽  
J. R. Hamilton

The influence of environmental temperature on the development of shock produced by a clamping technique in rats was studied. In experiments in which the animals were subjected to different environmental temperatures during the period of limb ischemia, the best survival was obtained with an air temperature of 15 °C. At 9.5 °C and 40 °C the rats did not survive the 10-hour clamping period. When the clamping was carried out at a standard temperature (27 °C) and the rats were then transferred to a room at different temperatures just prior to clamp release, the best survival was obtained at or near a temperature of 24 °C. The temperature in the colon of the shocked rats fell quickly in a cooler environment and rose in a warmer one. When chlorpromazine (0.35 mg/100 g rat) was given at the time of clamp removal to rats kept thereafter at 9.4 °C, 20–21 °C, 24 °C, and 30 °C, survival was significantly prolonged at air temperatures of 20–21 °C, but not at 9.4 °C, 24 °C, or 30 °C. Changes in humidity had no significant influence on survival. The experiments show that the optimum temperature during the period of ischemia is different from that for hindering the development of shock following a period of ischemia.


1959 ◽  
Vol 37 (1) ◽  
pp. 165-174
Author(s):  
R. E. Haist ◽  
Rebeka Moscarello ◽  
T. L. Friedlich ◽  
J. R. Hamilton

The influence of environmental temperature on the development of shock produced by a clamping technique in rats was studied. In experiments in which the animals were subjected to different environmental temperatures during the period of limb ischemia, the best survival was obtained with an air temperature of 15 °C. At 9.5 °C and 40 °C the rats did not survive the 10-hour clamping period. When the clamping was carried out at a standard temperature (27 °C) and the rats were then transferred to a room at different temperatures just prior to clamp release, the best survival was obtained at or near a temperature of 24 °C. The temperature in the colon of the shocked rats fell quickly in a cooler environment and rose in a warmer one. When chlorpromazine (0.35 mg/100 g rat) was given at the time of clamp removal to rats kept thereafter at 9.4 °C, 20–21 °C, 24 °C, and 30 °C, survival was significantly prolonged at air temperatures of 20–21 °C, but not at 9.4 °C, 24 °C, or 30 °C. Changes in humidity had no significant influence on survival. The experiments show that the optimum temperature during the period of ischemia is different from that for hindering the development of shock following a period of ischemia.


2012 ◽  
Vol 610-613 ◽  
pp. 1150-1154 ◽  
Author(s):  
Lu Zhang ◽  
Zhi Yao Su ◽  
Xiang Lin Wang

Temporal and spatial patterns of temperature and humidity in shelterbelts of Taxodium distichum were investigated using routine observation and gradient observation methods in sampling plots placed in Taxodium distichum shelterbelts, sugarcane, and open (blank) fields, respectively. The results showed that: 1) Taxodium distichum shelterbelts mitigated air temperature in July. Air temperature of Taxodium distichum shelterbelts was 0.7 °C and 1.7 °C lower than that of sugarcane field and blank field in July, respectively, while less change of air temperature in January was recorded. Air temperature at 20 cm from the ground in the Taxodium distichum shelterbelts was the highest in April, October and January, but the lowest in July; 2) Relative humidity in the Taxodium distichum shelterbelts was higher than in blank field through the four seasons, but lower than in sugarcane field in July, October and January. Relative humidity in sugarcane field and Taxodium distichum shelterbelts was higher near the ground, and relative humidity in sugarcane field increased significantly; 3) One-way ANOVA followed by Tukey’s HSD indicated that both air temperature and relative humidity were significantly different with a seasonal pattern among shelterbelts of Taxodium distichum, sugarcane field and open field (P<0.001).


2011 ◽  
Vol 50 (11) ◽  
pp. 2267-2269 ◽  
Author(s):  
Roland Stull

AbstractAn equation is presented for wet-bulb temperature as a function of air temperature and relative humidity at standard sea level pressure. It was found as an empirical fit using gene-expression programming. This equation is valid for relative humidities between 5% and 99% and for air temperatures between −20° and 50°C, except for situations having both low humidity and cold temperature. Over the valid range, errors in wet-bulb temperature range from −1° to +0.65°C, with mean absolute error of less than 0.3°C.


2021 ◽  
Vol 20 (2) ◽  
pp. 56-67
Author(s):  
Rundk Hwaiz ◽  
◽  
Katan Ali ◽  
Namir Al-Tawil

Background: COVID-19 was first reported in Erbil province in Iraq on March 19, 2020. The effect of lockdown on reducing the spread of the novel coronavirus and the effect of weather conditions (air temperature and humidity) on the daily reported number of cases and death rate of COVID-19 were investigated during April to July, 2020. Objective: To investigate the effect of lock down on reducing the spread of the novel coronavirus pandemic and the effect of weather conditions (air temperature and humidity) on the daily reported number of cases and death rate of COVID-19. Patients and Methods: The data collected during three different periods, the first (total lockdown), followed by the second period of lockdown relaxation, which was followed by the third period (interrupted relaxation of lockdown) that reported hundreds of new cases daily. The real-time PCR .assay was performed on suspected COVID-19 patients according to the protocol established by the World Health Organization. Results: Temperature and relative humidity were recorded in Erbil city in Iraq. Patients’ age ranged (2-70) years old. Out of (1469) patients confirmed positive with COVID-19, 57.7% of them were males, 31.3% were females, and the rest (11%) were children. The mean number of patients per day was 32.77 during the period of interrupted relaxation lockdown which was significantly higher than in the total-lock down period (3.88 patient), and the relaxation lockdown period (1.93 patient). The mortality rate per day was 0.77 during the period of interrupted relaxation lockdown was significantly higher than the rates (0.0%) of the other periods. Moreover, increasing the temperature increased the number of confirmed cases in July while, low relative humidity significantly increased the rate of reported cases. Conclusion: The increase in the number of reported cases of COVID-19, might be related to the interruption of lockdown. Moreover, the daily reported cases and mortality rates increased by increasing the temperature from April to June.


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