scholarly journals Too Hot to Nest? In a Hot Summer the Tortoise Chersina angulata Can Switch From Nesting to Facultative Viviparity

2022 ◽  
Vol 9 ◽  
Author(s):  
Gerald Kuchling ◽  
Margaretha D. Hofmeyr
Keyword(s):  
Heat Exposure ◽  
Reproductive Mode ◽  
Excessive Heat ◽  
Ambient Temperatures ◽  
Ground Temperatures ◽  
Egg Retention ◽  
Summer Heat ◽  
Air Temperatures ◽  
Definition Of ◽  
Nesting Season

In a captive colony of Chersina angulata in Cape Town, South Africa, we observed in 2015/16 retention of the last egg clutch inside the female until the hatching stage was reached, conforming to the generally accepted definition of viviparity. Retrospective climatic analysis indicates egg retention until the hatching stage co-occurred with unusually hot summer weather: the average air temperatures in December 2015 and January and February 2016 were higher than during the preceding five and the following 5 years when facultative viviparity could not be observed. Late December and January appears to be the critical period for females to either deposit their last clutch of the nesting season into a nest, or to retain the last clutch for embryonic development inside the female. Over the 28 December to 24 January period the minimum, average and maximum air temperatures in 2015–16 were about 3°C higher than in the five following years. This association of facultative viviparity with unusual summer heat suggests that hot ambient temperatures at the end of the nesting season may cue females to switch from oviposition to facultative viviparity. Compared to incubation in a nest this phenotypic plasticity of the reproductive mode—to retain during hot summers the season’s last clutch inside the female—may buffer the developing embryos from excessive heat exposure: females can thermo-regulate by moving among microhabitats whereas sun exposed shallow nests cannot escape high ground temperatures. This novel reproductive strategy has the potential to enhance the resilience of species to global warming.

scholarly journals Do Inflatable Bounce Houses Pose Heat-Related Hazards to Children?

2017 ◽  
Vol 98 (5) ◽  
pp. 893-897 ◽  
Author(s):  
Andrew Grundstein ◽  
J. Marshall Shepherd ◽  
Sarah Duzinski
Keyword(s):  
Heat Exposure ◽  
Heat Index ◽  
Ambient Conditions ◽  
National Weather Service ◽  
Excessive Heat ◽  
Air Temperatures ◽  
Typical Summer ◽  
Danger Level ◽  
Parents And Caregivers ◽  
Weather Service

Abstract Inflatable bounce houses provide a popular summer activity for children. Injuries such as sprains and fractures are widely acknowledged, but there is less awareness about possible hazards from excessive heat exposure. This study aims to identify whether conditions in the bounce house are more oppressive than ambient conditions on a typical summer day in Athens, Georgia. Results show that maximum air temperatures in the bounce house can reach up to 3.7°C (6.7°F) greater than ambient conditions, and peak heat index values may exceed outdoor conditions by 4.5°C (8.1°F). When considered within the context of the National Weather Service heat index safety categories, the bounce house reached the “danger” level in more than half of the observations, compared with only 7% of observations for ambient conditions. Parents and caregivers should be aware of heat-related hazards in bounce houses and closely monitor children, adjusting or canceling activities as conditions become more oppressive.

Global temperature and life

2017 ◽  
Author(s):  
Andrew Clarke
Keyword(s):  
Life Cycle ◽  
Marine Invertebrates ◽  
Natural World ◽  
Death Valley ◽  
Cell Interior ◽  
Ground Temperatures ◽  
Thermal Limits ◽  
Air Temperatures ◽  
Continental Shelves ◽  
Multicellular Organisms

The extreme meteorological surface air temperatures recorded to date are –89.2 oC in Antarctica, and 56.7 oC in Death Valley, California. Ground temperatures can be higher or lower than these air temperatures. The bulk of oceanic water is cold (< 4 oC) and thermally stable. Whilst data on limits to survival attract considerable attention, the thermal limits to completion of the life cycle (which define the limits to life) are much less well known. Currently identified upper thermal limits for growth are 122 oC for archaeans, 100 oC for bacteria and ~60 oC for unicellular eukaryotes. No unicells appear to grow below –20 oC, a limit that is probably set by dehydration-linked vitrification of the cell interior. The lower thermal limits for survival in multicellular organisms in the natural world extend to at least –70 oC. However in all cases known to date, completion of the life cycle requires summer warmth and the lowest temperature for completion of a multicellular eukaryote life cycle appears to be ~0 oC for invertebrates in glacial meltwater and ~–2 oC for marine invertebrates and fish living on the continental shelves around Antarctica.

scholarly journals Performance Evaluation of a CO2 Refrigeration System Enhanced with a Dew Point Cooler

Energies ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 1079 ◽  
Author(s):  
Martin Belusko ◽  
Raymond Liddle ◽  
Alemu Alemu ◽  
Edward Halawa ◽  
Frank Bruno
Keyword(s):  
Weather Conditions ◽  
Dew Point ◽  
Coefficient Of Performance ◽  
Experimental Program ◽  
Refrigeration System ◽  
Conventional System ◽  
Ambient Temperatures ◽  
Air Temperatures ◽  
Condenser Temperature

Dew point cooling (DPC) is a novel indirect evaporative cooling concept capable of delivering air temperatures approaching the dew point. Coupling this technology with CO2 refrigeration is well suited to minimising transcritical operation when the coefficient of performance (COP) is dramatically reduced in hot climates. A substantial experimental program was conducted to characterise this combination by testing a 20 kW CO2 refrigeration system subject to ambient temperatures above 40 °C. It was demonstrated that DPC operation not only avoided transcritical operation during such weather conditions, but also increased the COP by up to 140% compared to the conventional system. The combination of these technologies was successfully mathematically modelled, from which the optimum condenser inlet air temperature was identified for each condenser temperature. Using this optimum condition, it was possible to maximise the COP for a range of conditions applicable to the psychometric chart. An annual case study for Adelaide, Australia was conducted which demonstrated that optimally coupling DPC with CO2 refrigeration can reduce the annual energy consumption and peak demand by 16% and 47%, respectively, compared to a conventional CO2 booster system. Furthermore, the number of hours of transcritical operation was reduced from 3278 to 27.

scholarly journals Active layer thermal regime in two climatically contrasted sites of the Antarctic Peninsula region

2016 ◽  
Vol 42 (2) ◽  
pp. 457 ◽  
Author(s):  
F. Hrbáček ◽  
M. Oliva ◽  
K. Laska ◽  
J. Ruiz-Fernández ◽  
M. A. De Pablo ◽  
...  
Keyword(s):  
Active Layer ◽  
Antarctic Peninsula ◽  
Thermal Regime ◽  
Active Layer Thickness ◽  
Mean Annual Temperature ◽  
Climate Trends ◽  
Ground Temperatures ◽  
Air Temperatures ◽  
Discontinuous Permafrost ◽  
The Antarctic

Permafrost controls geomorphic processes in ice-free areas of the Antarctic Peninsula (AP) region. Future climate trends will promote significant changes of the active layer regime and permafrost distribution, and therefore a better characterization of present-day state is needed. With this purpose, this research focuses on Ulu Peninsula (James Ross Island) and Byers Peninsula (Livingston Island), located in the area of continuous and discontinuous permafrost in the eastern and western sides of the AP, respectively. Air and ground temperatures in as low as 80 cm below surface of the ground were monitored between January and December 2014. There is a high correlation between air temperatures on both sites (r=0.74). The mean annual temperature in Ulu Peninsula was -7.9 ºC, while in Byers Peninsula was -2.6 ºC. The lower air temperatures in Ulu Peninsula are also reflected in ground temperatures, which were between 4.9 (5 cm) and 5.9 ºC (75/80 cm) lower. The maximum active layer thickness observed during the study period was 52 cm in Ulu Peninsula and 85 cm in Byers Peninsula. Besides climate, soil characteristics, topography and snow cover are the main factors controlling the ground thermal regime in both areas.

CALCULATED DETERMINATION OF PRE-HEATING PARAMETERS FOR WELDING POLYETHYLENE PIPES FOR GAS PIPELINES AT LOW AIR TEMPERATURES.

2021 ◽  
pp. 29-31
Author(s):  
I. Tarabukin
Keyword(s):  
Low Temperatures ◽  
Weld Seam ◽  
Gas Pipelines ◽  
Ambient Temperatures ◽  
Regulatory Documents ◽  
Polyethylene Pipes ◽  
Heated Air ◽  
Air Temperatures ◽  
Different Characteristics

According to regulatory documents, welding can be performed at ambient temperatures from minus 15 ° C to plus 45 ° C. When laying gas pipelines at a lower outside temperature, it is necessary to organize their heating to the required temperature. In this case, the temperature of the heated air should not be more than plus 60 ° C. If you start working with a polyethylene (PE) pipe at low temperatures, then the PE pipe will have completely different characteristics. The weld seam may not be reliable.

A Field Evaluation of Construction Workers’ Activity, Hydration Status, and Heat Strain in the Extreme Summer Heat of Saudi Arabia

2020 ◽  
Vol 64 (5) ◽  
pp. 522-535 ◽  
Author(s):  
Mohammed Al-Bouwarthan ◽  
Margaret M Quinn ◽  
David Kriebel ◽  
David H Wegman
Keyword(s):  
Heart Rate ◽  
Saudi Arabia ◽  
Heat Stress ◽  
Heat Exposure ◽  
Heat Strain ◽  
Construction Workers ◽  
Hydration Status ◽  
Summer Heat ◽  
Cardiovascular Strain ◽  
Indoor And Outdoor

Abstract Objectives Assess the impact of summer heat exposure (June–September) on residential construction workers in Al-Ahsa, Saudi Arabia by evaluating (i) heart rate (HR) responses, hydration status, and physical workload among workers in indoor and outdoor construction settings, (ii) factors related to physiological responses to work in hot conditions, and (iii) how well wet-bulb globe temperature-based occupational exposure limits (WBGTOELs) predict measures of heat strain. Methods Twenty-three construction workers (plasterers, tilers, and laborers) contributed 260 person-days of monitoring. Workload energy expenditure, HR, fluid intake, and pre- and postshift urine specific gravity (USG) were measured. Indoor and outdoor heat exposures (WBGT) were measured continuously and a WBGTOEL was calculated. The effects of heat exposure and workload on heart rate reserve (HRR), a measure of cardiovascular strain, were examined with linear mixed models. A metric called ‘heat stress exceedance’ (HSE) was constructed to summarize whether the environmental heat exposure (WBGT) exceeded the heat stress exposure limit (WBGTOEL). The sensitivity and specificity of the HSE as a predictor of cardiovascular strain (HRR ≥30%) were determined. Results The WBGTOEL was exceeded frequently, on 63 person-days indoors (44%) and 91(78%) outdoors. High-risk HRR occurred on 26 and 36 person-days indoors and outdoors, respectively. The HSE metric showed higher sensitivity for HRR ≥30% outdoors (89%) than indoors (58%) and greater specificity indoors (59%) than outdoors (27%). Workload intensity was generally moderate, with light intensity work more common outdoors. The ability to self-pace work was associated with a lower frequency of HRR ≥30%. USG concentrations indicated that workers began and ended their shifts dehydrated (USG ≥1.020). Conclusions Construction work where WBGTOEL is commonly exceeded poses health risks. The ability of workers to self-pace may help reduce risks.

scholarly journals Motivation for Heat Adaption: How Perception and Exposure Affect Individual Behaviors During Hot Weather in Knoxville, Tennessee

Atmosphere ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 591 ◽  
Author(s):  
Alisa L. Hass ◽  
Kelsey N. Ellis
Keyword(s):  
Health Effects ◽  
Air Conditioning ◽  
Public Perception ◽  
Heat Exposure ◽  
Weather Conditions ◽  
Health Issues ◽  
Excessive Heat ◽  
Normal Behavior ◽  
Hot Weather ◽  
Heat Vulnerability

Heat is the deadliest meteorological hazard; however, those exposed to heat often do not feel they are in danger of heat-health effects and do not take precautions to avoid heat exposure. Socioeconomic factors, such as the high cost of running air conditioning, might prevent people from taking adaption measures. We assessed via a mixed-methods survey how residents of urban Knoxville, Tennessee, (n = 86) describe and interpret their personal vulnerability during hot weather. Thematic analyses reveal that many respondents describe uncomfortably hot weather based on its consequences, such as health effects and the need to change normal behavior, which misaligns with traditional heat-communication measures using specific weather conditions. Only 55% of those who perceived excessive heat as dangerous cited health as a cause for concern. Respondents who have experienced health issues during hot weather were more likely to perceive heat as dangerous and take actions to reduce heat exposure. Social cohesion was not a chief concern for our respondents, even though it has been connected to reducing time-delayed heat-health effects. Results support using thematic analyses, an underutilized tool in climatology research, to improve understanding of public perception of atmospheric hazards. We recommend a multi-faceted approach to addressing heat vulnerability.

scholarly journals Microtopographic control on the ground thermal regime in ice wedge polygons

2018 ◽  
Vol 12 (6) ◽  
pp. 1957-1968 ◽  
Author(s):  
Charles J. Abolt ◽  
Michael H. Young ◽  
Adam L. Atchley ◽  
Dylan R. Harp
Keyword(s):  
Thermal Conditions ◽  
Ground Temperature ◽  
The Arctic ◽  
Near Surface ◽  
Hydrologic Processes ◽  
Ground Temperatures ◽  
Air Temperatures ◽  
Winter Temperatures ◽  
Ice Wedge ◽  
Prudhoe Bay

Abstract. The goal of this research is to constrain the influence of ice wedge polygon microtopography on near-surface ground temperatures. Ice wedge polygon microtopography is prone to rapid deformation in a changing climate, and cracking in the ice wedge depends on thermal conditions at the top of the permafrost; therefore, feedbacks between microtopography and ground temperature can shed light on the potential for future ice wedge cracking in the Arctic. We first report on a year of sub-daily ground temperature observations at 5 depths and 9 locations throughout a cluster of low-centered polygons near Prudhoe Bay, Alaska, and demonstrate that the rims become the coldest zone of the polygon during winter, due to thinner snowpack. We then calibrate a polygon-scale numerical model of coupled thermal and hydrologic processes against this dataset, achieving an RMSE of less than 1.1 ∘C between observed and simulated ground temperature. Finally, we conduct a sensitivity analysis of the model by systematically manipulating the height of the rims and the depth of the troughs and tracking the effects on ice wedge temperature. The results indicate that winter temperatures in the ice wedge are sensitive to both rim height and trough depth, but more sensitive to rim height. Rims act as preferential outlets of subsurface heat; increasing rim size decreases winter temperatures in the ice wedge. Deeper troughs lead to increased snow entrapment, promoting insulation of the ice wedge. The potential for ice wedge cracking is therefore reduced if rims are destroyed or if troughs subside, due to warmer conditions in the ice wedge. These findings can help explain the origins of secondary ice wedges in modern and ancient polygons. The findings also imply that the potential for re-establishing rims in modern thermokarst-affected terrain will be limited by reduced cracking activity in the ice wedges, even if regional air temperatures stabilize.

Perceptions of, and Practices for Coping with, Heat Exposure among Male Arab Pilgrims to the Hajj, 1436

2019 ◽  
Vol 34 (02) ◽  
pp. 161-174 ◽  
Author(s):  
Zayid K. Al Mayahi ◽  
Ibrahim Ali Kabbash
Keyword(s):  
Saudi Arabia ◽  
Heat Exposure ◽  
Cross Sectional Study ◽  
Health Concern ◽  
Health Issues ◽  
Coping Behaviors ◽  
Cross Sectional ◽  
Excessive Heat ◽  
The Face ◽  
Earth’S Climate

Background:The problems associated with exposure to excessive heat are a key health concern throughout the world, and are likely to become increasingly important as Earth’s climate warms. Heat exposure is particularly problematic when large groups of people gather, but there is relatively little literature on the subject. Islam requires all adherents who are able to undertake a pilgrimage to Mecca (Saudi Arabia), known as the Hajj. This can result in huge numbers of pilgrims travelling to Mecca in the summer months, during which the temperatures can be very high, and to undertake physically demanding activities.Objective:The aim of this study was to identify the perception level of heat-related health issues and the coping behaviors adopted by pilgrims in the face of excessive heat exposure.Methods:A cross-sectional study was conducted in Mecca, Saudi Arabia among male Arab pilgrims performing Hajj of the Islamic calendar year 1436 (Summer 2015). Sample was divided into two strata: domestic pilgrims and international Arabs. A total of 14 camps were selected randomly, seven from each stratum. A total of 412 participants completed the questionnaire.Results:Mean age was 43.48 (SD = 13.42) years. Majority of pilgrims had never performed Hajj before (68.2%). Almost 89.5% among pilgrims more than 40 years of age had more water intake compared to only 76.5% for people under 40 years. Only 7.3% of educated people used to go out at noon time, and almost two-fold of pilgrims with lower educational level did so (15.4%). Approximately 51.8% among those who were aware of Mecca’s weather used cotton clothes, compared to 36.0% among pilgrims unaware of Mecca’s weather.Conclusion:This study reveals the extent of pilgrims’ understanding of, and abilities to cope with, excessive heat and also suggests coping strategies and options for improved understanding of heat-related health issues world-wide.Al Mayahi ZK, Ali Kabbash I. Perceptions of, and practices for coping with, heat exposure among male Arab pilgrims to the Hajj, 1436. Prehosp Disaster Med. 2019;34(2):161–174

Extremity skin temperature in British and Zebu cross cattle

1967 ◽  
Vol 69 (1) ◽  
pp. 1-7 ◽  
Author(s):  
K. G. Johnson ◽  
M. E. D. Webster
Keyword(s):  
Skin Temperature ◽  
Lower Leg ◽  
Zebu Cattle ◽  
Temperature Changes ◽  
Ambient Temperatures ◽  
Thermal Environments ◽  
Air Temperatures ◽  
Environmental Temperatures ◽  
Skin Temperatures ◽  
Trunk Skin

1. Extremity skin temperature changes in British and Zebu cross cattle examined in moderate thermal environments followed a thermoregulatory pattern similar to that describedby Whittow (1962). At low environmental temperatures, ear and lower leg skin temperatures were usually only slightly above air temperature. At a variable time after air temperatures began to rise or the animals were fed, extremity skin temperatures increased suddenly to near trunk skin temperature.2. In eight of the ten pairs of animals studied in rising ambient temperatures and during feeding after fasting for 36–72 hr, increases in ear temperature were measured in the British animal before similar changes occurred in its Zebu counterpart. Changes in lower leg skin temperature followed a similar pattern.Trunk skin temperatures and respiratory frequencies were significant higher in British cross animals than in Zebu cross animals of similar thermal history. The mean rectal temperature of both British and Zebu cattle was 38·5 °C.

Sign in / Sign up

Export Citation Format

Share Document