Effects Of High Ambient Temperature Research Articles

Effect of increasing ambient temperature on physiological changes, oxidative stress, nitric oxide, total antioxidant power, and mitochondrial activity of Nile tilapia (Oreochromis niloticus Linn.)

The objective of this study was to investigate the effect of high ambient temperature on physiological changes of live Nile tilapia (Oreochromis niloticus Linn.) and biochemical parameters in Nile tilapia blood cells. Live Nile tilapia and Nile tilapia blood cells were maintained at temperature ranges from 24 to 34 °C and 24–38 °C, respectively. Then, physiological parameters (body temperature, body color score, pulse rate, ventilation rate, oxygen saturation) of the live Nile tilapia and biochemical parameters (total antioxidant power, hydrogen peroxide, malondialdehyde, nitric oxide, and mitochondrial activity) of the Nile tilapia blood cells were measured for every 2 °C increase. It was found that when the ambient temperature increases, body temperature of live Nile tilapia continually increased. Total antioxidant power and hydrogen peroxide, pulse rate, body color score, malondialdehyde, ventilation rate and mitochondrial activity commenced to increase at 26, 28, 30, 32, 34 °C (P < 0.05), respectively. Blood oxygen saturation decreased at 32 °C (P < 0.05). The response of nitric oxide of Nile tilapia blood cells responded to increased temperature in two phases. In the first phase, nitric oxide decreased at 28–32 °C (P < 0.05), then increased and decreased again at a temperature of 38 °C (P < 0.05). These phenomena indicated that when the live Nile tilapias and the Nile tilapia blood cells were exposed to high ambient temperature, they were under heat stress and oxidative stress. In addition, physiological responses in the live Nile tilapia and biochemical changes in their blood cells when exposed to high ambient temperature occurred in a consistent manner when the temperature continually increased.

Too hot to thrive: a qualitative inquiry of community perspectives on the effect of high ambient temperature on postpartum women and neonates in Kilifi, Kenya

ObjectiveTo understand community perspectives on the effects of high ambient temperature on the health and wellbeing of neonates, and impacts on post-partum women and infant care in Kilifi.DesignQualitative study using key informant interviews, in-depth interviews and focus group discussions with pregnant and postpartum women (n = 22), mothers-in-law (n = 19), male spouses (n = 20), community health volunteers (CHVs) (n = 22) and stakeholders from health and government ministries (n = 16).SettingsWe conducted our research in Kilifi County in Kenya’s Coast Province. The area is largely rural and during summer, air temperatures can reach 37˚C and rarely go below 23˚C.Data analysisData were analyzed in NVivo 12, using both inductive and deductive approaches.ResultsHigh ambient temperature is perceived by community members to have direct and indirect health pathways in pregnancy and postpartum periods, including on the neonates. The direct impacts include injuries on the neonate’s skin and in the mouth, leading to discomfort and affecting breastfeeding and sleeping. Participants described babies as “having no peace”. Heat effects were perceived to be amplified by indoor air pollution and heat from indoor cooking fires. Community members believed that exclusive breastfeeding was not practical in conditions of extreme heat because it lowered breast milk production, which was, in turn, linked to a low scarcity of food and time spend by mothers away from their neonates performing household chores. Kangaroo Mother Care (KMC) was also negatively affected. Participants reported that postpartum women took longer to heal in the heat, were exhausted most of the time and tended not to attend postnatal care.ConclusionsHigh ambient temperatures affect postpartum women and their neonates through direct and indirect pathways. Discomfort makes it difficult for the mother to care for the baby. Multi-sectoral policies and programs are required to mitigate the negative impacts of high ambient temperatures on maternal and neonatal health in rural Kilifi and similar settings.

Effect of thermal manipulation on embryonic development, hatching process, and chick quality under heat-stress conditions

Thermal stress is a risk that threatens poultry welfare and productivity. Thermal manipulation during egg incubation is considered a prevention strategy used to mitigate the detrimental effects of high ambient temperatures on birds. This study aimed to investigate the impact of thermal manipulation, applied to chicken breeder's eggs during the incubation period, on embryonic development, hatching characteristics, and chick quality, as well as posthatch thermotolerance and performance. A total of 1,200 fertile eggs were randomly and equally assigned into 2 groups of 3 replicates (200 eggs/replicate), using a randomized experimental design followed by t test. The first group eggs (G1) were subjected to a commercial setter temperature of 37.5°C with 55% relative humidity (RH) throughout the incubation period (1-18 d) and served as a control, while the second group eggs (G2) were treated the same commercial setter conditions until the 11th day of the incubation, then the eggs were exposed to a higher temperature of 39.5°C with 60% RH for 4 h daily from the 12th to the 18th day of incubation. All eggs in both groups were exposed to the same temperature condition of 37.2°C with 70% RH from the 19th to the 22nd days of the incubation (hatching period). Three hundred hatched female chicks per each treatment group were transferred into a closed-system house and distributed randomly into 20 floor pens (15 birds per pen). At the 8th week of age, birds were exposed to a daily heat challenge by raising the temperature to 35°C for 6 h until the 18th week of the chick's age. According to the results, thermal manipulation at 12 to 18 d of egg incubation positively (P ≤ 0.05) affected several studied traits. It improved some embryonic development traits, such as embryonic weight and tibia length, as well as some hatching parameters, such as hatching time and pipped eggs. It also improved hatched chick quality traits, including the chick's weight, length, and activity. In addition, it enhanced the posthatch chick's thermotolerance and body weight. Hatched chicks of G2 had significantly (P ≤ 0.05) higher total protein, albumin, IgM, glucose, calcium, total antioxidant, and T3 than G1 chicks. They also had significantly (P=0.001) higher body weight (23%) at the 18th week of age than G1, as well as a lower feed conversion ratio (20.71%) than G1 chicks at 8 to 18 wk of age. Therefore, it is recommended to apply thermal manipulation during egg incubation, particularly at 12 to 18 d, for its positive effects on the pre- and posthatch performance.

Increase in summertime ambient temperature is associated with decreased sick leave risk in Helsinki, Finland

ObjectivesClimate change has increased attention to the health effects of high ambient temperatures and heatwaves worldwide. Both cause-specific mortality and hospital admissions are studied widely, mainly concentrating on warmer climates, but studies focusing on more subtle health effects and cold climates lack. This study investigated the effect of summertime daily ambient temperatures and heatwaves on sick leaves in the employed population in Helsinki, Finland, a Nordic country with a relatively cold climate. MethodsWe obtained from the City of Helsinki personnel register data on sick leaves for the summer months (June–August) of 2002–2017. We estimated the overall cumulative association of all and short (maximum 3-day) sick leaves with daily mean temperature over a 21-day lag period using a negative binomial regression model coupled with a penalized distributed lag non-linear model (penalized DLNM). The association of sick leaves with heatwaves (cut-off temperature 20.8 °C), and prolonged heatwaves, was estimated using a negative binomial regression model coupled with DLNM. We adjusted the time series model for potential confounders, such as air pollution, relative humidity, time trends, and holidays. ResultsIncreasing daily temperature tended to be associated with decreased overall cumulative risk of sick leaves and short sick leaves over a 21-day lag period. In addition, heatwaves and prolonged heatwaves were associated with decreased overall cumulative risk of sick leaves compared to all other summer days: RR 0.87 (95 % CI 0.78 to 0.97) and RR 0.83 (95 % CI 0.70 to 0.98), respectively. ConclusionsThis research suggests that summertime daily temperatures that are high for this northern location have protective effects on the health of the working population.

The effect of gallic acid on malondialdehyde, hydrogen peroxide and nitric oxide that influence viability of broiler blood cells at high ambient temperatures

ABSTRACT 1. The objective of this study was to measure the effect of gallic acid on levels of ferric reducing antioxidant power, malondialdehyde, hydrogen peroxide, nitric oxide and the viability of broiler blood cells (BBCs) when exposed to high ambient temperature. 2. The BBCs were maintained at 41.5°C (control group, CG) or at ambient temperatures ranging from 41.5°C to 46°C. At 41.5°C to 46°C, BBCs were diluted with gallic acid at 0 (positive control group, PCG), 6.25, 12.5, 25 and 50 µM, respectively. Ferric reducing antioxidant power, malondialdehyde, hydrogen peroxide, nitric oxide and viability of BBCs were investigated. 3. Hydrogen peroxide, malondialdehyde and nitric oxide for the CG was lower than PCG (P < 0.05). However, the viability of CG was higher than PCG (P < 0.05). At 41.5 to 46°C, malondialdehyde, hydrogen peroxide, and nitric oxide of BBCs diluted with gallic acid were lower compared to PCG (P < 0.05). Viability of BBCs diluted with gallic acid was higher than PCG (P < 0.05). 4. These results indicated that gallic acid could reduce the adverse oxidative effects of high ambient temperature on BBCs, with an optimum dilution rate of 12.5 µM.

Multi-Objective Optimization of an Inlet Air-Cooled Combined Cycle Power Plant

Abstract The present work aims to investigate the effect of inlet air cooling in conjunction with other input parameters on the exergetic performance of combined cycle power plants (CCPP). To mitigate the adverse effects of high ambient temperature on performance, the CCPP has been equipped with an inlet air cooler, which lowers the air temperature at the inlet of the compressor. Under a specific combination of input parameters, the analysis revealed a maximum increase in net specific work, efficiency, and exergetic efficiency of 14.16%, 3.93%, and 5.65%, respectively. Moreover, the effects of multiple input parameters were analyzed individually and in combination. This was done in order to identify the most influential exergy-affecting parameters for the CCPP, which turned out to be the degree of cooling, pressure ratio, and turbine inlet temperature. The simulated model is then subjected to two sets of multi-objective optimization using a genetic algorithm, considering the above parameters as design variables. According to the Pareto set of optimal solutions, cooling the inlet air by 16.5 K results in the highest net-specific work output and increased exergy destruction. Increased exergy destruction, on the other hand, is undesirable. However, if the cost of power per unit is high, this could be economically advantageous.

The Effect of Drinking Water Temperature and Stocking Density on Broiler Performance, Meat Quality and Some Behavioral Traits at High Ambient Temperature

The present study examined the effect of drinking water temperature and stocking density on performance (cumulative body weight gain, feed intake, and feed conversion ratio), meat quality, and behaviour traits (eating, drinking, lying, standing, and dust bathing) in broilers. A total of 360 broiler chicks (Ross 308) were randomly divided into 6 experimental groups, in a 2x3 factorial arrangement of drinking water temperature (10°C or 31°C), with stocking density (12, 15 or 18 birds/m2), each consisting of 4 replicate pens. Meat quality traits (pH15, L*, CL, and WHC), lying and standing behaviours were affected by water temperature. The stocking density significantly affected the cumulative body weight gain, feed intake, feed conversion ratio, color of breast meat [lightness (L*), redness (a*), yellowness (b*)] of broiler chickens. In conclusion, management practices such as stocking density and drinking water temperature in broilers could reduce the detrimental effects of high ambient temperature on growth performance, meat quality traits, and behaviour.

Effect of high ambient temperature on physiological responses during incremental exercise in Thoroughbred horses

Several reports have suggested that the risk of exertional heat illness (EHI) in Thoroughbred racehorses increases in high ambient temperatures. Heat dissipation in horses during exercise becomes less efficient when the body temperature and ambient temperature are close. Therefore, we hypothesised that exercise at 40 °C may increase body temperature, oxygen consumption, and cardiac output during incremental exercise tests compared to 20 and 30 °C. Six trained Thoroughbred horses were studied in a randomised, crossover design at three ambient temperatures with a 6-day washout period. Using a 3% inclined treadmill, horses performed incremental exercise tests at 1.7, 3.5, 6, 8, and 10 m/s for 90 s at ambient temperatures of 20, 30, and 40 °C. The effects of ambient temperature at 10 m/s on physiological variables were analysed using mixed models (P&lt;0.05). Pulmonary arterial temperature and rectal temperature at 40 °C were higher than those at 20 °C (P&lt;0.001) and 30 °C (P&lt;0.001). Similarly, oxygen consumption (vs 20 °C, P=0.009; vs 30 °C, P=0.006) and cardiac output (vs 20 °C, P=0.001; vs 30 °C, P=0.001) at 40 °C were higher than those at 20 and 30 °C. Arterial O2 partial pressure, O2 saturation, and pH at 40 °C were lower than those at 20 and 30 °C. Arterial CO2 partial pressure at 40 °C was higher than that at 20 and 30 °C. No differences were observed in arterial-mixed venous O2 concentration difference (P=0.391) and plasma lactate concentration (P=0.134) at different ambient temperatures. These results indicate that exercise at 40 °C causes excessive high body temperature, decreased running economy, and increased cardiac output compared to exercise at 20 and 30 °C. We strongly suggest that trainers and veterinarians should anticipate the occurrence of increased thermal stresses when ambient temperature is extremely high even in dry conditions and prepare to mitigate the risk of EHI from the perspective of equine welfare.

Effects of warming and fertilization on paddy N2O emissions and ammonia volatilization

Several studies have proved the influence of warming to N2O emissions and NH3 volatilization in paddies. However, it is not clear whether the performance is affected by fertilization. Here, we performed a field trial to evaluate the impacts of warming and fertilization on N2O emissions and NH3 volatilization from paddies. A free air temperature increase system was used for the experimental warming treatment (ET), while the control treatment used ambient temperature (AC). Both ET and AC treatments were combined with nitrogen (N) fertilizer (CF) or without fertilizer input (CK). The results showed insignificant interaction effects of warming and fertilization on seasonal cumulative N2O emissions and NH3 volatilization. Compared with AC, seasonal cumulative N2O emissions and ammonia volatilization in the ET treatment increased by 118.44% and 38.41%, respectively. Moreover, fertilization surprisingly stimulated seasonal cumulative N2O emissions and ammonia volatilization; values were 15.91 and 2.35 times higher than those in the CK treatment. These results imply that fertilization could intensify the increasing effect of warming on N2O emissions and ammonia volatilization. The variable importance for the projection (VIP) analysis revealed that soil N transformation (the rates of N mineralization, nitrification, and denitrification) was the key to affecting reactive N loss rather than soil fertility. Additionally, the ammonia volatilization rate increased with ambient temperature and NH4+-N solution concentration in the microsystem. Importantly, there was a "surge" inflection point of the ammonia volatilization rate under both high ambient temperature (30 °C) and NH4+-N concentration (15 mg/L) conditions. Our findings indicate that warming did promote N2O emissions and ammonia volatilization in paddies by accelerating soil N transformation, which might be aggravated by fertilization. Furthermore, the "surge" effect of high ambient temperature and NH4+-N concentration on ammonia volatilization deserves further attention.

Effects of Heat Stress on Growth Performance, Carcass Traits, Physiological Components, and Biochemical Parameters in Local Algerian Growing Rabbits

Heat stress is a detrimental factor affecting the welfare of all livestock, especially rabbits, as they are sensitive to high temperatures. The current study investigated the effect of high ambient temperature on growth performance, slaughter traits, physiological indicators, and some hematological and biochemical parameters in Algerian local growing rabbits. A total of 48 local rabbits of both sexes (35 days old) were allotted into two groups (24 per group). The control group rabbits were exposed to an ambient temperature and humidity, averaging 21.8 ± 1.3°C and 51.7 ± 3.6%, respectively. Rabbits in the heat stress group were subjected to a warm ambient temperature and humidity of 30.5 ± 1.82°C and 65.5 ± 7.2%, respectively. The growth performance was measured and calculated from 35 to 91 days of age. Physiological indicators (rectal, skin, and ear temperatures, respiratory, and heart rates) were examined at 88 days of age. The carcass traits, blood metabolites, and hematological parameters of rabbits were measured and calculated at slaughter (92 days of age). The obtained results indicated a decrease in body weight, daily gain, and daily feed intake of rabbits in heat stress rabbits, compared to the control group. However, feed conversion ratio was significantly higher in the heat stress group, compared to the control. Heat stress group rabbits showed significantly higher blood metabolite levels, except the glycemia, which was similar in both groups. No significant effect of heat stress was found on the carcass yield, anterior, posterior, and intermediate parts of the carcass. However, the yield of the other components of the carcass (liver, kidney, peritoneal and inter-scapular fat) was significantly lower in the heat stress group. In the heat stress group, rectal, skin, and ear temperatures as well as heart and respiratory rates, were significantly higher than those of the control group. In the present experimental conditions, exposure of local rabbits to chronic heat stress could induce some changes to biological, physiological, and biochemical parameters leading to altered growth performance.

Impact of high temperature on PV productivity in hot desert climates

Hot dry climate regions enjoy high solar irradiation, albeit with high ambient temperatures. These two factors have a contradictory effect on the power generated from PV systems. This work studies the combined effect of high ambient temperature and high irradiation on the net performance of PV systems. The study is based on monitoring a grid-connected 5 kW PV system installed on the rooftop of the Energy Research Center of the University of Khartoum, Sudan. The performance was monitored by meteorological and power measurement equipment from April 2017 to March 2018. The results showed stable power output from the PV system with an average final yield of 4.57 kWh/kWp and a 0.21 standard deviation from this average value. The stability in power output is due to the compensation of the efficiency degradation due to high temperature by high irradiation in summer. This is combined with the relatively low irradiation in winter compensated by the low temperature effect in winter. The annual deviation of the temperature and irradiation is small in Khartoum due to its proximity to the equator. The semi desert climate, offers Khartoum notably few annual cloudy hours. These characteristics were compared with the annual performance of other countries with different climates. The conclusion from this work on hot dry regions is that despite the negative effect of temperature, the annual output power from the system tends to be stable due to the substitution contributed by the regionally high radiation and the relatively cool winter climate.

Effects of lowering dietary protein content without or with increased protein-bound and feed-grade amino acids supply on growth performance, body composition, metabolism, and acute-phase protein of finishing pigs under daily cyclic heat stress.

This study investigated the effects of a low-protein diet with or without an increase in dietary protein and feed-grade amino acids (AAs) on the growth performance, body composition, metabolism, and serum acute-phase proteins of finishing pigs reared in thermoneutrality or cyclic heat stress conditions. A total of 90 gilts (67.7 ± 6.2 kg) were distributed in a 2 × 3 factorial arrangement (two ambient temperatures and three diets). Ambient temperatures (AT) were thermoneutral (TN, 22 °C for 24 h) and cyclic heat stress (CHS, 12 h to 35 °C and 12 h to 22 °C). The evaluated diets (D) were high crude protein (HP); low CP-free AA-supplemented diets (LPAAs); low CP-free AA-supplemented diets and digestible Lys level (+20%), and Lys:AA ratios above recommendations (LPAA+). The experimental period lasted 48 d (two experimental phases: days 0-27 and days 28-48, respectively). CHS pigs had higher skin temperature (P < 0.05) than TN pigs. Pigs in CHS had higher rectal temperature (P < 0.05) than TN pigs until day 38 but similar (P > 0.10) to TN pigs from 38 to 45 d. For the entire experiment, CHS pigs had lower (P < 0.05) final BW, average daily gain and daily feed intake, net energy intake, body lipid, bone mineral, lipid deposition, energy retention, Lys and CP intake, and nitrogen excretion than TN pigs. The level of CP intake impacted nitrogen excretion, nitrogen retention efficiency, and urea as pigs fed HP had the highest values, and pigs fed LPAA had the lowest values (P < 0.05). On day 27, CHS pigs had lower (P < 0.05) free triiodothyronine than TN pigs. LPAA+ pigs had lower (P < 0.05) insulin than LPAA. On day 48, CHS pigs had lower (P < 0.05) thyroxine, albumin, and lactate than TN pigs. On day 27, pigs fed LPAA+ had higher (P < 0.05) lactate than pigs fed HP or LPAA. Both AT and D were enough to stimulate the immune system as CHS pigs had lower (P < 0.05) transferrin and 23-kDa protein levels than TN pigs, and HP pigs had higher haptoglobin than LPAA on day 27. These results confirm the deleterious effects of high AT on performance, body composition, metabolism, and immune system stimulation in finishing pigs. These data also show that a diet with low levels of CP can be provided to pigs in CHS without affecting performance and body composition while reducing nitrogen excretion. However, the use of a diet with an AA level above the requirements obtained by increasing intact protein and free AA did not attenuate the impact of CHS on performance and body composition of pigs.

Association between daily temperature and hospital admissions for urolithiasis in Ganzhou, China: a time-series analysis.

Urolithiasis was a global disease and it was more common in southern China. This study looked into the association between daily temperature and urolithiasis hospital admissions in Ganzhou, a large prefecture-level city in southern China. In Ganzhou City from 2016 to 2019, a total of 60,881 hospitalized cases for urolithiasis from 69 hospitals and meteorological data were gathered. The effect of high ambient temperature on urolithiasis hospital admissions was estimated using a distributed lag nonlinear model. Stratified analysis was done to examine sex differences. The study found that in Ganzhou of China, the exposure-response curves approximated a "J" shape which across genders were basically similar. The maximum lag effect occurred on the second day after high temperatures for males but on the third day for females. Compared to the 10°C reference temperature and considering the cumulative lag effect of 10days, the relative risks of the daily mean temperature at the 95th percentile on the total, male, and female hospital admissions for urolithiasis were 2.026 (95% CI: 1.628, 2.521), 2.041 (95% CI: 1.603, 2.598), and 2.030 (95% CI: 1.552, 2.655), respectively, but the relative risks between sex were not statistically significant (p = 0.977). Urolithiasis morbidity risk in China could be exacerbated by high temperatures. The effect of high temperature on urolithiasis was similar across genders.

How do high ambient temperatures affect infant feeding practices? A prospective cohort study of postpartum women in Bobo-Dioulasso, Burkina Faso

ObjectiveTo examine the effects of high ambient temperature on infant feeding practices and childcare.DesignSecondary analysis of quantitative data from a prospective cohort study.SettingCommunity-based interviews in the commune of Bobo-Dioulasso, Burkina...

Effects of High Ambient Temperature on Small Intestinal Morphology and Colonic Microbiota in Weaned Piglets.

Simple SummaryThermal stress (TS) is a critical challenge in the swine industry, but knowledge about the influence of TS on intestinal development and microbiota in piglets is still scarce. Thus, the present study investigated the effects of high ambient temperature on growth performance, small intestinal morphology, and colonic microbiota in weaned piglets. Our results showed that high ambient temperature had negative effects on growth performance and colonic microbiota of weaned piglets.A total of 16 crossbred (Duroc × Landrace × Yorkshire) barrows, with an average initial body weight of 8.61 ± 0.24 kg (28 days of age), were randomly allotted into the control group (CON group) and high ambient temperature group (HT group) with 8 replicates per group, 1 pig per replicate. The ambient temperature of the CON group was controlled at 26 ± 1 °C, and the HT group was controlled at 35 ± 1 °C. The study lasted for 21 days. Our results showed that high ambient temperature significantly decreased the average daily feed intake (ADFI) and average daily gain (ADG) of piglets (p < 0.05), and the feed-to-gain ratio was significantly increased (p < 0.05). The liver index, spleen index, and thymus index of piglets in the HT group were significantly decreased (p < 0.05). The villous height (VH) of the duodenum, jejunum, and ileum of piglets in the HT group was significantly decreased (p < 0.05), whereas the crypt depth (CD) of the duodenum was significantly increased (p < 0.05), and the VH-to-CD ratio of the duodenum and ileum was significantly decreased (p < 0.05). The piglets in the HT group showed a higher (p < 0.05) observed-species index, PD whole tree index, and Shannon index, indicating that there was a significant difference in species richness and diversity between the two groups. At the genus level, the piglets in the HT group showed a greater (p < 0.05) percent of Desulfovibrio, Occillibater, and Catenisphaera. HT reduced glycan biosynthesis and metabolism, transport and catabolism, lipid metabolism, amino acids metabolism, secondary metabolites biosynthesis, aging, endocrine system, signaling molecules, and interaction of colon microbiota (p < 0.05), and increased signal transduction, cell motility, transcription, and genetic information processing (p < 0.05).

Influence of a Supplemental Blend of Essential Oils Plus 25-hydroxy-vitamin-D3 on Feedlot Cattle Performance during the Early-growing Phase under Conditions of High-ambient Temperature

Background: During the first stage of fattening, performance of cattle is more affected by high ambient load. A strategy to mitigate the negative effects of high ambient temperatures on energy efficiency is by monensin supplementation. However, the present concern about the use of antibiotics as feed additives has led to search for safe alternatives. Due to its nature, essential oils and supplementary vitamin D3 represent a potential substitute to monensin in cattle subjected to high environmental heat load. For this reason, The objective of this study was to compare supplemental monensin vs the novel combination essential oils plus vitamin D3 on growth performance and dietary NE of feedlot bulls exposed to elevated ambient temperature during the initial 84-d on feed. Methods: Ninety crossbreed young bulls (228.0±7.1 kg initial weight) were used in 84-d trial to evaluate a blend of essential oils plus 25-hydroxy-Vit-D3 as a feed additive to alleviate the harmful effects of the high-ambient temperature on feedlot cattle performance during the early-growing phase. Dietary treatments (9 replicates/treatment) were supplemented with: 1) 24 mg of sodium monensin/kg diet DM (MON), or with 2) 119.12 mg/kg diet DM of a combination of standardized mixture of essential oils (119 mg) plus 0.12 mg of 25-hydroxy-vitamin-D3 (EO+HyD). Average THI was 82.7±3.2. Result: There were no treatment effects on day-to-day fluctuations in DMI. However, EO+HyD tended to increase DMI (4.3%, P=0.06). Supplemental EO+HyD increased daily weight gain (8.3%, P less than 0.01) and gain-to-fed ratio (4.0%, P=0.03). Supplemental EO+HyD tended to increase estimated dietary net energy (2.5%, P=0.07) and observed-to-expected dietary NE ratio (3.0%, P=0.07). This effect can be attributed to a 7% reduction in the maintenance requirement. The combination of EO+HyD may be a valuable tool to optimize growth-performance and feed efficiency of cattle under conditions of high ambient heat load.

Effects of high ambient temperature on the accuracy of thermoluminescent dosimeters for environmental monitoring

Thermoluminescence dosimeters (TLDs) are widely used for both personal and environmental dosimetry. TLDs should have high accuracy under different conditions. The TL signal can drop over time because of fading (loss of signal due to thermally induced recombination of trapped charriers), thus leading to underestimation of the irradiation dose. The Saudi climate is extremely hot for most of the year, which could significantly affect TLD measurements. Therefore, the effect of ambient temperature, storage time and irradiation dose were investigated both in laboratory controlled-temperature conditions and field experiments, for two commercial dosimeters: Harshaw (TLD-100H™) and RADCARD (MCP-N™), which are used for environmental monitoring. The irradiated TLDs were exposed to a range of ambient temperatures (25 °C–65 °C) then stored for 30, 60, and 90 days. A signal fading due to increasing ambient temperature and storage time was generally observed. MCP-N shows good stability and is less responsive to increasing ambient temperature compared to TLD-100H. TLD-100H is less affected by storage time compared to MCP-N. Irradiation doses play a role in TL signal fading, and TLDs irradiated with 5 mSv have a higher rate of loss compared to those irradiated with 2 mSv in all TLD types. The obtained results permitted to conclude that all TLD types used in this study suffer from TL signal fading, and its degree varies between TLD types.

Effects of High Ambient Temperature on Electric Vehicle Efficiency and Range: Case Study of Kuwait

The use of electric vehicles (EVs) provides a pathway to sustainable transport, reducing emissions and contributing to net-zero carbon aspirations. However, consumer acceptance has been limited by travel range anxiety and a lack of knowledge about EV technology and its infrastructure. This is especially the case in hot and oil-rich areas such as Kuwait, where transport is predominantly fossil fuel-driven. Studying the effects of high ambient temperature on EV efficiency and range is essential to improve EV performance, increase the user base and promote early adoption to secure more environmental benefits. The ability to determine the energy consumption of electric vehicles (EVs) is not only vital to reduce travel range anxiety but also forms an important foundation for the spatial siting, operation and management of EV charging points in cities and towns. This research presents an analysis of data gathered from more than 3000 journeys of an EV in Kuwait representing typical vehicle usage. The average energy intensity and consumption of the car/kilometre travelled were calculated for each journey, along with ambient temperature measured by the vehicle. The analysis indicates that energy intensity reaches a minimum at a starting temperature between 22 °C and 23 °C. Energy intensity rises with decreasing temperature below this point and with increasing temperature above this point. The results show that many vehicle journeys started with high temperatures, with about half of journeys starting at 30 °C or above and approximately a quarter at 40 °C or above. Fitting a model to the empirical data for trip starting temperature and energy intensity, average efficiency is impacted at high car temperatures, with energy intensity modelled at 30 °C and 40 °C to be higher by 6% and 22%, respectively. These findings have implications for vehicle range, EV charging infrastructure and car storage and parking provision.

Effects of High Ambient Temperature and Surface Quality on Tribological Properties of Si3N4

Effects of High Ambient Temperature and Surface Quality on Tribological Properties of Si3N4

The Impact of High Ambient Temperature on Human Sperm Parameters: A Meta-Analysis.

Background:Global warming, lifestyle, or working in a high temperature environment leads to have increased health risk factors. This meta-analysis was conducted to determine the impact of high ambient temperature on male reproductive function.Methods:Scientific articles were screened in the database including MEDLINE, EMBASE, National center for biotechnology information (NCBI) or Web of Science with relating keywords. Impact data of high ambient temperature on semen parameters were extracted and analyzed by STATA software according to the Random Effects Model. The high ambient temperature exposure group and Non-exposure group were compared using the standard mean difference (SMD). Publications were evaluated for publication bias by Egger test.Results:Nine articles were finally selected from databases examining the effect of high ambient temperature on male reproductive health of 356 men from Iran, Italy, Thailand, China, Egypt. High ambient temperature showed a significant decrease in the seminal parameters, semen volume during each ejaculation (SMD = −0.74; 95% CI −1.11, −0.36), sperm concentration (SMD = −1.07; 95% CI −1.42, −0.72), total sperm count (SMD = −1.52; 95% CI −2.96, −0.08), sperm motility (SMD = −1.93; 95% CI −2.83, −1.04), sperm progressive motility (SMD = −1.65; 95% CI −2.39, −0.91) and normal morphology (SMD = −2.41; 95% CI −3.30, −1.52).Conclusion:High ambient temperature negatively affects sperm quality, including decreased semen volume, sperm count, sperm concentration, motility and normal morphology. This might lead to protective strategies to avoid the adverse effects of high ambient temperature on male fertility.