Effect Of High Air Temperature Research Articles

Excess mortality related to high air temperature: Comparison of the periods including 1994 and 2018, the worst heat waves in the history of South Korea.

Climate change has caused extreme weather events, including frequent summer heat waves. We examined how the effects of high air temperatures on mortality have changed between the two study periods (1991-1995 and 2015-2019), including 1994 and 2018, the worst heat wave years in the meteorological history of South Korea. Temperature data from the Korea Meteorological Administration and mortality data from Statistics Korea were used in this study. We used distributed lag nonlinear models to estimate the cumulative relative risks (CRRs) to determine the association between daily maximum temperature in summer (June to September) and mortality. CRRs were estimated for each province and pooled using a random-effects meta-analysis for all provinces. Maximum temperature and annual average days in heat wave were 37.7°C and 11.8 in 1991-1995 and 38.3°C and 18.8 in 2015-2019. The slope of the CRR for mortality increases with increasing temperature and has been steeper in the past than in recent years and steeper in those over 65 than in those under 65. Excess mortality has recently declined compared with that in the past. The impact of high summer temperatures on mortality changed between the two periods, suggesting improved population resilience.

Effects of high air temperature, drought, and both combinations on maize: A case study

High air temperature (HAT) and natural soil drought (NSD) have seriously affected crop yield and frequently take place in a HAT-NSD combination. Maize (Zea mays) is an important crop, thermophilic but not heat tolerant. In this study, HAT, NSD, and HAT-NSD effects on maize inbred line Huangzao4 -were characterized. Main findings were as follows: H2O2 and O- accumulated much more in immature young leaves than in mature old leaves under the stresses. Lateral roots were highly distributed near the upper pot mix layers under HAT and near root tips under HAT-NSD. Saccharide accumulated mainly in stressed root caps (RC) and formed a highly accumulated saccharide band at the boundary between RC and meristematic zone. Lignin deposition was in stressed roots under NSD and HAT-NSD. Chloroplasts increased in number and formed a high-density ring around leaf vascular bundles (VB) under HAT and HAT-NSD, and sparsely scattered in the peripheral area of VBs under NSD. The RC cells containing starch granules were most under NAD-HAT but least under HAT. Under NSD and HAT-NSD followed by re-watering, anther number per tassel spikelet reduced to 3. These results provide multiple clues for further distinguishing molecular mechanisms for maize to tolerate these stresses.

Evaluation of cognitive performance in high temperature with heart rate: A pilot study

Real-time monitoring and evaluation of cognitive performance based on physiological indicators is a potentially new measure to ensure high air temperature safety. Heart rate might be an appropriate physiological indicator, yet it still needs several direct shreds of evidence. This study analyzed the relation between heart rate and cognitive performance at high air temperatures, based on the experimental data obtained from three phases of climate-controlled experiments. The climate-controlled experiments include five temperature levels of 26, 30, 33, 37, and 39 °C, and two relative humidity levels of 50% and 70%. During the experiments, eight cognitive tests were conducted to assess the basial cognitive performance, heart rate was continuously monitored, and the ratings of alertness and thermal sensation, comfort, and acceptability were documented. A total of 104 healthy subjects took part in the three phases of experiments, and 1478 valid samples were obtained. By analyzing the experimental data comprehensively, the results show that when the heart rate went up to 90bpm, the speed and accuracy of Stroop and d2 test would decline significantly(p < 0.05). The accuracy of Visual learning, Addition, Multiplication, and Typing only dropped significantly when the heart rate reach a level of 100bpm(p < 0.05). There was an inverted U-shaped relation between the relative accuracy of cognitive tests and heart rate. Based on the quadratic regression equation with a downward opening, the Heart Rate-Cognitive performance (HR-CP) model was built up. The R2 value of all regression equations is close to or greater than 0.8. These results suggest that heart rate might be a potential physiological indicator to evaluate the effects of high air temperature on cognitive performance.

Short-term heat effects and effect modification by ambient air pollution on cardiovascular and respiratory mortality across 148 cities from 13 European countries – Results of the EXHAUSTION project

Background and Aim: Epidemiological evidence on the potential interactive effects of high air temperature and air pollution on cause-specific mortality remains inconclusive and limited to selected locations. We investigated the effects of temperature on cardiovascular and respiratory mortality and its effect modification by particulate matter with a diameter &amp;#x2264; 2.5 µm [PM₂.₅] and ozone [O₃] during summer months (May-September) in 148 cities across 13 European countries. Methods: For these cities, we obtained daily counts of cardiovascular and respiratory mortality and daily exposure data between 2000 and 2018. We used location-specific confounder-adjusted Quasi-Poisson regression with a tensor product between air temperature and the air pollutant. We extracted temperature estimates at low, medium, and high levels of pollutants defined as the 5th, 50th, and 95th percentile of location-specific air pollutant concentrations. A random-effects multilevel meta-analytical model was used to derive the country-specific and overall estimates. Results: High summer temperatures were associated with increased cardiovascular and respiratory mortality. We further observed modification of the heat effects by elevated levels of PM₂.₅ and O₃ in most locations, with stronger effects for respiratory than cardiovascular mortality. For example, the percent increase in respiratory mortality per increase in the 2-day average summer temperature from the 75th to the 99th percentile was 9.2% (95% Confidence Interval [CI] 8.9-9.4), 13.0% (95% CI 12.8, 13.2), and 19.8% (95% CI 19.5, 20.2) at low, medium, and high levels of PM₂.₅, respectively. Conclusion: We observed significant modification of the heat effects by elevated levels of PM₂.₅ and O₃ leading to an increased risk of cardiovascular and respiratory mortality. With both temperature and air pollutant concentrations foreseen to increase considering climate change, targeted adaptation and mitigation measures are crucial to enhance resilience and sustainable development in alignment with EU climate change policies. Keywords: Air temperature, air pollution, cause-specific mortality, effect modification, Europe

Evaluation of the effect of high air temperature on the behavioural activity and physical performance of animals (in a rat model)

Introduction. The profession of firefighters belongs to extreme activities. Fire hazards include flames, sparks, heat flow, elevated ambient temperatures, increased concentrations of toxic combustion and thermal decomposition products, decreased oxygen concentrations, and reduced visibility in smoke. High air temperature during fire extinguishing is one of the main adverse physical factors affecting firefighters’ bodies. Material and methods. The study was carried out on 124 outbred white male 3-month rats weighing 250-300 g, divided randomly into two groups: the first group (62 rats) underwent single hyperthermia. The second group (62 rats) experienced daily hyperthermia for 14 days. The study of the behavioural activity of animals was carried out after single and prolonged hyperthermia using the following methods: “Open field”, “Elevated cruciform maze”, Porsolt’s test, running on a treadmill. The tests were performed two times: the first time - before exposure, the second - after, with intervals between tests of at least two weeks. Results. The data obtained indicate that the high ambient temperature causes changes in the behavioural responses in animals, which is expressed by an increase in the level of anxiety, a decrease in motor and research activity, the development of depressive states, and a decrease in physical endurance. Conclusion. An experimental model of extreme heat exposure on animals showed the emergence and persistence of changes in animals’ behavioural activity and physical performance indicators. This experiment can be used to study the long-term effects of high temperatures on firefighters’ bodies.

Direct and indirect effects of high temperatures on fledging in a cooperatively breeding bird

Abstract High temperatures and low rainfall consistently constrain reproduction in arid-zone bird species. Understanding the mechanisms underlying this pattern is critical for predicting how climate change will influence population persistence and to inform conservation and management. In this study, we analyzed Southern Pied Babbler Turdoides bicolor nestling survival, daily growth rate and adult investment behavior during the nestling period over three austral summer breeding seasons. High temperatures were associated with lower body mass, shorter tarsi, and reduced daily growth rates of nestlings. Our piecewise structural equation models suggested that direct impacts of temperature had the strongest influence on nestling size and daily growth rates for both 5-day-old and 11-day-old nestlings, followed by temperature-related adjustments to provisioning rates by adults. Rainfall and group size influenced the behavior of provisioning adults but did not influence nestling growth or survival. Adjustments to adult provisioning strategies did not compensate for direct negative effects of high air temperatures on nestling size or daily growth rates. Detailed mechanistic data like these allow us to model the pathways by which high temperature causes nest failure. In turn, this could allow us to design targeted conservation action to effectively mitigate climate effects.

Suppression of red color development associated with anthocyanin accumulation in the epicarp of grape (Vitis labrusca × vinifera cv. Ruby Roman) berries caused by air temperature in daylight periods higher than 33°C during maturation

The effect of high air temperature on the anthocyanin accumulation in the epicarp of 'Ruby Roman' grape (Vitis labruscana × vinifera) berries was examined. Seventeen types of anthocyanin were detected from the epicarp tissue of the matured berries using HPLC. Since a strong positive correlation (P < 0.005, R2 = 0.937) was confirmed between the degree of color density evaluated using a color chart and the total content of anthocyanins quantified separately, it seems possible to trace anthocyanin accumulation using the color chart on each berry during maturation at different air temperatures. Four conditions were designed for cooling the fruit clusters with a spot-cooling system, which can keep air temperature 4–5°C lower for 60–70 days after the full–bloom, i.e. consecutive (0:00–24:00) cooling, daytime (6:00–18:00) cooling, nighttime (18:00–6:00) cooling and no–cooling (control). The degree of color density showed statistically higher (P < 0.05) values in the consecutive–cooling treatment than that of the control through the post–cooling duration (0–15 days after cooling). To clarify the effect of temperature zones with or without daylight on the anthocyanin accumulation in the epicarp, percentage of exposure time to each temperature zone of < 21, 21–24, 24–27, 27–30, 30–33, 33–36 and 36°C ≤ were calculated for both daylight and dark periods, separately. Correlations of the ∆ time% (the amount of difference in percentage of exposure time from the control) with the ∆ color degree (the amount of difference in degree of color density from the control) in the daylight period were positive at temperature zones of < 30°C, but turned to negative at those of 30°C ≤. The fact that correlation coefficient was statistically significant (P < 0.05) at the temperature zones of 27–30°C (positive) and 33–36°C (negative) in the daylight period shows that the threshold where the anthocyanin accumulation starts to be suppressed exists within 30–33°C.

Mesocosm study of microalgae in different weather conditions

Microalgae have valuable contributions in carbon dioxide sequestration. There are no much investigations about motivation of mix microalgae productivity in outdoor cultures. This study aims to evaluate microalgae biomass production in outdoor mesocosms under different weather conditions. The experiment was done in Tilapia pond in the hatchery of fisheries of Universiti Putra Malaysia. Weather parameters were recorded daily. Microalgae seeds were obtained from Tilapia pond effluent and added to eight floating aerated mesocosms. Mesocosms were divided into four treatments. Two g triple supper phosphate: 20g Urea were used as fertilizers. Physical and chemical conditions, microalgae primary productivity and biomass, and species composition were measured every two days. Three cycles were categorized as mix, wet and dry cycles based on weather recording scores. Water quality parameters in Treatments and controls cultures showed significant variations. Primary production variables were higher in the fertilized non-sheltered mesocosms (treatment 1). Productivity variables were lower in the dry cycle and higher in the mix cycle. The highest value of fixed CO2 was (3.2) mg/L/d in treatment 1 in the mix cycle, while the lowest value was (0.11) mg/L/d in treatment 3 and control 1 in dry cycle. Changes in weather patterns are seen in the light and temperature values. Microalgae biomass was lower in dry weather conditions because of effect of high air temperature. Weather conditions and different treatments significantly influenced microalgae species composition, due to the sensitivity in some of them to different light intensities. Chlorophytes were the most abundant due to their ability to adapt with different culture conditions.

Persistent Increases in Nighttime Heat Stress From Urban Expansion Despite Heat Island Mitigation

AbstractUrban areas generally have higher near‐surface air temperature and lower air humidity than rural areas. Little is known about how heat stress, the combined effect of high air temperature and high humidity on human physiology, will be affected by future urban land expansion. Here we use a mesoscale numerical weather prediction model to examine the effects of urban land expansion from 2000 to 2050 on heat stress (measured as wet‐bulb globe temperature, WBGT) in the urban areas of China, India, and Nigeria, which are projected to account for one‐third of global urban population growth through 2050. Our results show that urban expansion slightly reduces heat stress during the day (∼0.2°C) but substantially intensifies it at night, by ∼1°C on average and by up to 2–3°C in five mega‐urban regions (MURs). These effects exist with or without climate change induced by rising concentrations of greenhouse gases (GHGs). Installing cool roofs—an urban heat island mitigation measures—can reduce the daytime WBGT by 0.5–1°C, partially offsetting the heat stress conditions caused by GHG‐induced climate change. However, even with cool roofs, the nighttime WBGTs are higher by 0.3–0.9°C over the whole countries studied, and by 1–2°C in the MURs under the urban expansion scenario, compared to the situation in which urban areas remain unchanged. These results show that future urban expansion and heat island mitigation can result in potential daytime benefits but also persistent nighttime risks.

Simulated heat waves reduce cognitive and motor performance of an endotherm.

Heat waves cause mass mortality of animals, including humans, across the globe annually, which has drawn new attention to how animals cope with high air temperatures. Recent field research has explored behavioral responses to high air temperatures, which can influence reproductive success and mortality.Less well studied are the effects of high air temperatures on cognition, which may underlie behavioral changes. Specifically, it is poorly known if cognitive declines occur at high temperatures, and if cognitive and motor components of behavior are similarly affected.We tested how well zebra finches (Taeniopygia guttata castanotis), a model for cognition research, performed two learned foraging tasks (color association and detour‐reaching) at mild (22°C) and high (43 and 44°C) air temperatures that occur naturally in their range. We habituated birds to the trial conditions and temperatures on days preceding the test trials and at the trial temperature for 30 min immediately prior to each test trial. Trials lasted less than 10 min. At high air temperatures, zebra finches exhibited heat dissipation behaviors during most tasks, suggesting thermoregulatory challenge.Cognitive performance declined at high air temperatures in two of three measures: Color association was unaffected, but birds missed more food rewards, and did more unproductive behaviors. Motor performance declined at high temperatures on the color association task, including longer times to complete the task, move between food rewards, and process individual seeds. Performance declines varied among components of behavior and among individuals.We combined our behavioral data with existing climate data and predicted that in the austral summer of 2018–2019, zebra finches experienced air temperatures that caused cognitive and motor declines in our captive birds in 34% and 45% of their Australian range, respectively.This study provides novel experimental evidence that high air temperatures cause cognitive and motor performance decline in birds. Further, our results provide insights to how those declines might affect bird ecology and evolution. First, differences in declines among behavioral components may allow identification of behaviors that are most susceptible to decline in the wild. Second, variation in performance declines and heat dissipation behaviors among individuals suggests variability in heat tolerance, which could lead to differential fitness in the wild. Last, these results suggest that high air temperatures cause cognitive declines in the wild and that understanding cognition could help refine predictive models of population persistence.

CLINICAL AND HAEMATOLOGICAL PARAMETERS IN LACTATING COWS UNDER THE INFLUENCE OF HIGH AIR TEMPERATURE AND VOLUNTARY AND FORCED MILKING

The effect of high air temperature on clinical and haematological parameters in lactating cows during voluntary and forced milking when they are kept in frame cowsheds made of metal structures were studied. During forced (milking parlour) and voluntary (milking robot) milking cows’ heart rate increased by 5 and 15 beats per minute, respectively, and the number of respiratory movements increased from 50 to 77 at high air temperature in the barn, which is 1.7 and 2.1 times higher than at optimal values of this indicator of the microclimate. It was identified that the body temperature of cows depended on the air temperature in the barn during forced milking. It increased to 35.8 – 37.9 ° C, which was 6.9 – 7.5 ° C above its optimal value, while this indicator of the breast increased from 31.6 to 33.3 ° C up to 32.3 – 38.5 ° C at high values. Humidification and of lactating cows’ body surface irrigation in combination with increasing the speed of its movement to 1.2 m / s in the storage reduced lactating cows’ body surface to 33.2 – 34.5 ° C, that ,an average, turned out to be in 2.5 – 4.7 ° C lower than similar indicators for animals in the barn. The concentration of haemoglobin in lactating cows’ blood is lower by 15.6 g/l, the number of stab neutrophils by 3.9% and monocytes by 2.6% compared with the optimum under high air temperature. The haemoglobin in the blood was lower by 47.2 g/l, the number of leukocytes by 1.95 g/l and monocytes by 6.25% compared with the optimum for voluntary milking at high temperatures. It was concluded that the high temperature of the air observed in frame barns made of metal structures in summer had a negative effect on the clinical condition and haematological parameters of lactating cows. Key words: milking cows, milking parlor, milking robot, forced and voluntary milking, air temperature, clinical and hematological parameters

CLINICAL AND HAEMATOLOGICAL PARAMETERS IN LACTATING COWS UNDER THE INFLUENCE OF HIGH AIR TEMPERATURE AND VOLUNTARY AND FORCED MILKING

The effect of high air temperature on clinical and haematological parameters in lactating cows during voluntary and forced milking when they are kept in frame cowsheds made of metal structures were studied. During forced (milking parlour) and voluntary (milking robot) milking cows’ heart rate increased by 5 and 15 beats per minute, respectively, and the number of respiratory movements increased from 50 to 77 at high air temperature in the barn, which is 1.7 and 2.1 times higher than at optimal values of this indicator of the microclimate. It was identified that the body temperature of cows depended on the air temperature in the barn during forced milking. It increased to 35.8 – 37.9 ° C, which was 6.9 – 7.5 ° C above its optimal value, while this indicator of the breast increased from 31.6 to 33.3 ° C up to 32.3 – 38.5 ° C at high values. Humidification and of lactating cows’ body surface irrigation in combination with increasing the speed of its movement to 1.2 m / s in the storage reduced lactating cows’ body surface to 33.2 – 34.5 ° C, that ,an average, turned out to be in 2.5 – 4.7 ° C lower than similar indicators for animals in the barn. The concentration of haemoglobin in lactating cows’ blood is lower by 15.6 g/l, the number of stab neutrophils by 3.9% and monocytes by 2.6% compared with the optimum under high air temperature. The haemoglobin in the blood was lower by 47.2 g/l, the number of leukocytes by 1.95 g/l and monocytes by 6.25% compared with the optimum for voluntary milking at high temperatures. It was concluded that the high temperature of the air observed in frame barns made of metal structures in summer had a negative effect on the clinical condition and haematological parameters of lactating cows. Key words: milking cows, milking parlor, milking robot, forced and voluntary milking, air temperature, clinical and hematological parameters

Combined effect of inlet air cooling and fouling on performance of variable geometry industrial gas turbines

The performance of industrial gas turbines is closely tied to the intake air temperature and component performance degradation caused by fouling, erosion, and foreign object damage (FOD). Generally, under hot and humid conditions an increase in the ambient intake air temperature induces a decline in gas turbines performance. With this regard, inlet air cooling (IAC) is an established technique that has been applied to reverse the deteriorating effects of high air temperatures. In this study, a steady-state off-design model for a single-shaft industrial gas turbine (Taurus 70) with a variable geometry has been developed to analyze a cumulative effect of fouling and variable ambient conditions on gas turbines performance. The validation of GasTurb 12, simulations was achieved by comparing the results with the Solar Turbines product catalog. The study has been segregated into four different scenarios: (i) with inlet air cooling, (ii) without inlet air cooling, (iii) with Variable Inlet Guide Vane (VIGV) schedule, and (iv) without VIGV schedule. With an increase in fouling severity level, thermal efficiency and specific fuel consumption (SFC) showed clear deterioration. However, with the integration of the IAC technique, the thermal efficiency and SFC improved that translate into economic gain. A novel idea has also been explored to investigate the effect of VIGV scheduling on performance improvement. It is observed that the deployment of the VIGV schedule improves the thermal efficiency and SFC that were previously deteriorating due to fouling. Hence, it is concluded that the integration of inlet air cooling with variable geometry engine can improve the performance of industrial gas turbines especially in hot climate regions such as the Middle East and Southeast Asian countries.

Association between high air temperature and mortality in summer: A multi-city analysis in China

Objective: To understand the associations between changes of high air temperature and mortality in summer in 31 cities in China. Methods: Daily mortality and meteorological data in 31 cities in China from January 1, 2008 to December 31, 2013 were collected. Distributed lag nonlinear model was used to evaluate the association between high air temperature change and mortality in early summer and late summer after controlling for the long-term trend and the effect of "day of week" . Results: The relative risk of high air temperature on mortality was higher in early summer, with relative risk in the range of 1.08-2.14 in early summer and 1.03-1.67 in late summer. In early summer, the influence of high temperature on mortality was mainly below 5(th) of percentile and above 50(th) of percentile, while in late summer it was mainly above 95(th) of percentile. The lag effect of high air temperature on mortality in early summer was 6 days, while the lag effect in late summer was only about 2 days. Conclusions: Association existed between high air temperature and mortality. The influence of high air temperature on mortality in early summer was stronger than that in late summer. It is necessary to take targeted protection measures.

An observational study of high air temperature on diabetes mortality in six cities in China

Objective: To evaluate the effect of high air temperature on diabetes mortality in six cities in China. Methods: Daily diabetes mortality and meteorological data were collected from January 1, 2008 to December 31, 2013 in Beijing, Tianjin, Shanghai, Chongqing, Guangzhou, and Shenyang. Distributed lag nonlinear model was used to evaluate the association between high air temperature and diabetes mortality after controlling for the long-term trend and the effect of "day of week" . Results: The effect of high air temperature on diabetes mortality varied in different cities, the maximum cumulative relative risk of Beijing, Tianjin, Shanghai, Chongqing, Guangzhou and Shenyang were 1.37 (lag 2 days), 1.32 (lag 0 days), 1.40 (lag 0 days), 1.26 (lag 2 days), 1.48 (lag 2 days) and 1.67 (lag 3 days). The daily diabetes death numbers were similar in men and women, but the death number in women were slightly higher than that in men, no gender specific characteristics were found. The death number was highest in age group 65-84 years, accounting for >60% of the total deaths, the difference was significant. Conclusion: The mortality of diabetes increased obviously in the context of high air temperature environment.

The Effects of High Air Temperature and Waterlogging on the Growth and Physiological Responses of Hot Pepper

고온기 고추재배시 고온과 침수에 따른 피해를 구명하고자 시험을 실시하였다. 온도처리는 비가림하우스 1동은 적온구, 다른 1동은 고온구로 하여 적온구는 하우스내 온도가 25°C가 되면 자동으로 환기팬 및 측장이 열려서 환기가 되도록 하였 고, 고온구는 35°C가 되면 자동으로 환기팬 및 측창이 열리도록 설정하였다. 침수처리는 정식후 54일(정식후 2화방 착과가 완료된 시점)에 하우스를 5등분하여 무침수(0시간) 처리구와 침수(12, 24, 48 및 72시간) 처리구를 두었고, 점적호스를 이용 하여 계속적으로 관수를 하였다. 그 결과 생육특성은 25°C 무침수 처리구가 다른 처리구보다 좋은 경향을 보였다. 광합성속 도는 25°C 무침수 처리구가 19.6μmol CO2· m-2·s-1로 처리구중에서 가장 좋았으며 25°C 72시간 침수처리구가 16.5μmol CO2· m-2·s-1로 가장 낮았다. 근활력은 25°C 24시간 침수처리구와 35°C 72시간 침수처리구가 0.042로 처리구중에서 가장 높았으 며 25°C 12시간 침수처리구가 0.02로, 25°C 무침수처리구의 0.032에 비해서 63% 수준으로 가장 낮았다. 주당 적과의 수확과 수 및 수량 역시 고온구인 35°C 무침수 처리구가 162개/주, 1,662g/주로 처리구중에서 가장 많았고, 적온구인 25°C의 12, 24 및 48시간 침수처리구가 적었다. 수량은 고온인 35°C 무침수 처리구가 수확과수가 많아서 3,697kg/10a 로 처리구중에서 가 장 높았으며 적온구인 25°C 12시간, 24시간 및 48시간 처리구가 25°C 무침수처리구 대비 수량지수가 75‚70% 수준으로 낮았 다. 따라서 고추는 침수시간이 길어질수록 생육, 광합성률, 근활력 및 수량을 감소시키며, 72시간 침수된 고추포장은 물을 빼 주고 정상적인 환경관리를 9일정도 해주면 광합성과 기공전도도가 정상으로 회복되는 것으로 나타났다 .

The Effect of High Air Temperature on Anthocyanin Concentration and the Expressions of Its Biosynthetic Genes in Strawberry &amp;lsquo;Sachinoka&amp;rsquo;

The Effect of High Air Temperature on Anthocyanin Concentration and the Expressions of Its Biosynthetic Genes in Strawberry &amp;lsquo;Sachinoka&amp;rsquo;

Effects of High Air Temperature on Rice Grain Quality and Yield under Field Condition

High air temperature (HAT) limits grain yield and quality in rice (Oryza sativa L.). This study was conducted to determine the effects of HAT from R3 (panicle exertion from boot) to R8 stage (physiological maturity) on rice grain yield and quality (milling, appearance, cooking and eating, and nutrition qualities). A split‐spot experiment based on randomized complete design was performed, involving two cultivars (japonica Koshihikari and indica IR72), two temperature treatments, and three replicates. Rice cultivars as main plot treatments were grown in a paddy field. The HAT and natural air temperature (NAT) treatments were regarded as subplot. Percentage of chalky kernel increased, whereas head rice yield, amylose and starch contents, and grain yield decreased in both cultivars under HAT, when compared with those under NAT. The HAT enhanced values of peak viscosity and breakdown, but decreased value of setback for Koshihikari. Conversely, starch viscosity characteristics for IR72 were unaffected by HAT. Relative content of amino acids in grains were enhanced; however, absolute content of some amino acids did not increase due to the reduction of grain weight under HAT. The HAT also increased absolute content of grain protein in IR72, but not in Koshihikari. The present study indicates that HAT decreased rice milling, appearance qualities and grain yield, while it positively influenced not only cooking and eating qualities in Koshihikari but also some nutritional components of grains in both cultivars.

Effects of High Air Temperature in the Summer of 2010 on the Kernel Quality of the Heat-tolerant Rice Cultivar ‘Genkitsukushi’

Effects of High Air Temperature in the Summer of 2010 on the Kernel Quality of the Heat-tolerant Rice Cultivar ‘Genkitsukushi’

South American sea lions in Peru have a lek‐like mating system

AbstractFive years of behavioral observations revealed significant effects of high air temperatures and breeding site topography on the mating system of South American sea lions in Peru. Unlike most polygynous mammals that defend females or fixed territories, male sea lions in Peru maintained positions along the shoreline where females passed each day to thermoregulate, and where most copulations occurred. Sex ratios (1 male per 17 females) and male mating success were extremely skewed (14% of males achieved 50% of the copulations, and 25% of them did not copulate at all). The mass daily movements of females toward the water and cool substrate of the shoreline, along with a highly skewed sex ratio, accentuated the difficulty for males to monopolize and restrict female movements. Females moved freely and chose their mates, unlike in temperate regions of their range where male South American sea lions control groups of females or access to tide pools. Our observations indicate that the South American sea lion in Peru has a lek‐like breeding system. This is a rare alternative to the common male strategies of defending females and resources, and is likely an evolutionary product of their highly skewed sex ratio, protracted breeding season, and the extreme subtropical climate where they breed.