summer heat
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2022 ◽  
Vol 160 ◽  
pp. 107058
Author(s):  
Jiaming Miao ◽  
Shurong Feng ◽  
Minghao Wang ◽  
Ning Jiang ◽  
Pei Yu ◽  
...  

2022 ◽  
Vol 9 ◽  
Author(s):  
Gerald Kuchling ◽  
Margaretha D. Hofmeyr

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.


Author(s):  
Yao Feng ◽  
Hong Wang ◽  
Wenbin Liu ◽  
Fubao Sun ◽  
Huijuan Cui

Multiple indices have been created to measure hot conditions that may cause discomfort, stress even death to humans. However, distinctions among these indices and their performance in measuring heat remain undisclosed. We conduct a comparative study of multiple heat indices and revisit the spatiotemporal changes in summer heat across China. The maximum temperature-based index, more sensitive to average and maximum temperatures, suggests a larger increasing trend (0.42°C/10a) in heat intensity than those average temperature-based ones which are more sensitive to minimum temperature. The absolute threshold-based heat-day indices are not so applicable as the relative ones in measuring the increasing heat days over the Tibetan Plateau. During 1960–2018, significant ( p < 0.05) increasing trends in heat intensity (0.11–0.42°C/10a) and heat day (0.63–2.67 days/10a) are revealed with a jump-like increase after the mid-1990s at the country level. Stronger heat intensity occurs over the southeast and north China with larger increasing trends over the Tibetan Plateau and northwest China. Northern China with larger increasing heat intensity and days should take effective measures of adaptation to reduce suffering from the summer heat. Given differences among multiple indices and the performance over different regions, a rational selection of heat index considering the research subject of interest and regional climatology is highly recommended.


2021 ◽  
Vol 6 (5) ◽  
pp. 19-29
Author(s):  
A. K. Tikhaze ◽  
G. G. Konovalova ◽  
M. K. Osyaeva ◽  
M. D. Smirnova ◽  
T. V. Martynyuk ◽  
...  

Background. In view of the worsening forecast for global temperature rise worldwide, it seems relevant to study the effects of abnormal heat waves on systemic regulatory processes in people with chronic diseases, in particular coronary artery disease (CAD).Aims. This study aimed to investigate the effect of hyperthermia on oxidative stress parameters in patients with various severity of CAD and in healthy subjects.Materials and methods. We studied the level of malonic dialdehyde (MDA) and the activity of Cu,Zn-containing superoxide dismutase (Cu,Zn-SOD) in healthy subjects under conditions of 30-day long simulated hyperthermia and in patients with different severity of CAD after the summer heat wavesResults. We revealed signs of oxidative stress in healthy volunteers during model hyperthermia that manifested as an increase in content of MDA in blood plasma. At the  same time we observed increasing activity of Cu,Zn-SOD in erythrocytes that  utilizes reactive oxygen species. The increase of Cu,Zn-SOD activity started with a certain latency what also can be explained by de novo enzyme biosynthesis induction. We also studied oxidative stress parameters in patients at high and moderate cardiovascular risk according to the SCORE risk chart with uncomplicated CAD course and in patients with complicated CAD with severe coronary damage according to angiography during the summer heat waves. We observed accumulation of MDA in blood plasma and increasing activity of erythrocyte Cu,Zn-SOD in patients with uncomplicated CAD. At the same time we noted that accumulation of MDA in blood plasma was not followed by any increase in activity of red blood cell Cu,Zn-SOD in patients with severe complicated CAD. This fact indicates dysregulation of free radical processes in patients with severe course of CAD during the heat waves.Conclusions. The dysregulation of free-radical processes in patients with a severe clinical course of CAD has been revealed. 


2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Xiaona Zhuang ◽  
Zujing Chen ◽  
Xiaohong Sun ◽  
Fangjun Li ◽  
Junyi Luo ◽  
...  

Abstract Background Herbal tea residue (HTR) is generally considered to be the waste of herbal tea beverage production while it still retains rich nutrients and active substances. The main aim of the present study was to investigate the effect of fermentation technology on improving the quality of HTRs, and focus on the fermented HTR-induced alleviation of summer heat stress in fattening cattle. Results In this study, the waste HTR was fermented and then fed to a total of 45 fattening cattle that were divided into 3 groups (fermented HTR replaced 0, 15, 30% of the forage component of the diet), and the feeding experiment was lasted for 40 days. The physiological indexes, growth performance and fecal microbiota of fattening cattle were evaluated and results showed that fermented HTR could effectively reduce the respiratory rate and rectal temperature of fattening cattle under heat stress, increase the daily feed intake and daily gain, and improve the antioxidant content and blood immune index. In addition, we studied the fecal microbiota composition of 6 fattening cattle in control and 30% HTR substitution groups and found fermented HTR significantly changed the composition of fecal microbiota and increased microbial diversity, and correlation analysis suggested that the bacteria were closely related to fecal SCFA levels of fattening cattle under heat stress. Conclusions In this study, fermented HTR replaced 30% of the forage component of the diet that can change the intestine microorganisms, maintain health and alleviate the heat stress of fattening cattle.


2021 ◽  
pp. 269-285
Author(s):  
Kenneth W. Noe

In the late summer and early autumn of 1862, Gen. Braxton Bragg’s Kentucky Campaign failed to regain Tennessee or add Kentucky to the Confederacy. Starting in Mississippi, Bragg’s Confederate army had first entered Tennessee. After Maj. Gen. Edmund Kirby Smith’s smaller Confederate army invaded Kentucky, Bragg followed. Maj. Gen. Don Carlos Buell’s Federal army trailed Bragg north before diverting to Louisville. Summer heat and a massive drought made campaigning onerous, while supporting Confederate actions in northeastern Mississippi failed to divert troops from Bragg’s path. Bragg won a confused tactical victory at Perryville, but his outnumbered army retreated to Tennessee along with Kirby Smith. Throughout the campaign, enslaved Kentuckians seeking emancipation sought protection from Union forces. On the fringes, a brutal guerrilla war flared up. Bragg’s ultimate failure secured Union control of Kentucky for the remainder of the war.


2021 ◽  
Author(s):  
Xiaona Zhuang ◽  
Zujing Chen ◽  
Xiaohong Sun ◽  
Fangjun Li ◽  
Junyi Luo ◽  
...  

Abstract Background: Herbal tea residue (HTR) is generally considered to be the waste of herbal tea beverage production while it still retains rich nutrients and active substances. The main aim of the present study was to investigate the effect of fermentation technology on improving the quality of HTRs, and focus on the fermented HTR-induced alleviation of summer heat stress in fattening cattle.Results: In this study, the waste HTR was fermented and then fed to a total of 45 fattening cattles that were divided into 3 groups (fermented HTR replaced 0%, 15%, 30% of Pennisetum purpureum respectively), and the feeding experiment was lasted for 40 days. The physiological indexes, growth performance and fecal microorganisms of fattening cattle were evaluated and results showed that fermented HTR could effectively reduce the respiratory rate and rectal temperature of fattening cattle under heat stress, increase the daily feed intake and daily gain, and improve the antioxidant content and blood immune index. In addition, we studied the fecal microorganisms composition of 6 fattening cattles in each group and found fermented HTR significantly changed the composition of fecal microorganisms and increased microbial diversity, and correlation analysis suggested that the bacteria were closely related to fecal SCFA levels of fattening cattle under heat stress. Conclusions: we suggested that 30% of fermented HTR can help maintain health of fattening cattle and alleviate the heat stress of fattening cattle by the change of intestine microorganisms.


Author(s):  
Yassine Kharbouch ◽  
Mohamed Ameur

Abstract Climate change has become a real challenge in different fields, including the building sector. Understanding and assessing the impact of climate change on building energy performance is still necessary to elaborate new climate-adaptive design measures for future buildings. The building energy consumption for heating and cooling is mainly related to the building envelope thermal performance. In this study, the winter heat loss and summer heat gain indicators are proposed to assess and analyse the potential impact of climate change on opaque building envelope elements for different climate zones in Morocco over the next 40 years. For that purpose, a one-dimensional heat transfer model is used to simulate the heat transfer through the multi-layer structure of the wall/roof. A medium climate change scenario is considered in this study. The results showed that the current average walls and roof summer heat gain is expected to increase of about 19.2–54.3% by the 2060s depending on the climate zone, versus a less important decrease in winter heat loss varies between –10.6 and –20.6%. This paper provides a reliable evaluation of the climate change impact on building envelope thermal performance, which leads to better adjustments in future building envelope designs.


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