32 The ventricular response to passive heat stress has predominately been studied in the 33 supine position. It is presently unclear how acute changes in venous return influence ventricular 34 function during heat stress. To address this question, left ventricular (LV) systolic and diastolic 35 function were studied in seventeen healthy men (24.3 + 4.0 yrs; mean + SD), using two36 dimensional t...

background: heat stress is one of the harmful factors present in many workplaces. it can lead to performance loss and low functionality of the labor force. therefore, the aim of this study was to evaluate exposure to heat stress and its consequent performance loss among workers functioning in indoor high-temperature workplaces. materials and methods: this descriptive, analytical study was condu...

Many birds can defend body temperature (Tb) far below air temperature (Ta) during acute heat exposure, but relatively little is known about how avian heat tolerance and evaporative cooling capacity varies with body mass (Mb), phylogeny or ecological factors. We determined maximum rates of evaporative heat dissipation and thermal end points (Tb and Ta associated with thermoregulatory failure) in...

Exercise in heat stress exacerbates performance decrements compared to normothermic environments. It has been documented that the performance decrements are associated with reduced efferent drive from the central nervous system (CNS), however, specific factors that contribute to the decrements are not completely understood. During exertional heat stress, blood flow is preferentially distributed...

Eight spring wheat cultivars were evaluated under three heat stress conditions (early, late and very late) in order to identify suitable cultivars to develop heattolerant genotypes resistant to future global warming. Results from the study indicate that stress did not negatively affect flag leaf area in ‘Prodip’ and ‘Sufi’, flag leaf dry matter partitioning in ‘Prodip’, ‘BARI Gom-26’ and ‘S...

continual heat stress affects approximately 7 million hectares of wheat in developing countries, while terminal heat stress is a problem in 40% of temperate environments, which cover 36 million hectares throughout the world. heat tolerance is a quantitative and complex trait that doesn’t have much success in direct selection. for this purpose, however, a thorough understanding of physiological ...

Acute heat stress activates visceral sympathetic nerve discharge (SND) in young rats, and the functional integrity of the rostral ventrolateral medulla (RVLM) is required for sustaining visceral sympathoexcitation during peak increases in internal body temperature (T(c)). However, RVLM mechanisms mediating SND activation to hyperthermia remain unknown. In the present study, we investigated the ...

Accumulating evidences indicate that the hypothalamic neuropeptide orexins or hypocretins are involved in stress-induced responses in mammals. Recently, we found that orexin is expressed and secreted from avian muscle cells, however its regulation is still unknown. In this study, we investigated the effect of heat and oxidative stress, the most challenging stressors in poultry production, on th...

The mechanism underlying temperature-dependent shortening of action potential (AP) duration was examined in the fish (Carassius carassius L.) heart ventricle. Acute temperature change from +5 to +18 degrees C (heat stress) shortened AP duration from 2.8 +/- 0.3 to 1.3 +/- 0.1 s in intact ventricles. In 56% (18 of 32) of enzymatically isolated myocytes, heat stress also induced reversible openin...

in order to study the effects of terminal heat stress and nitrogen on morphophysiological characteristics, anue (agronomical nitrogen use efficiency) and yield of canola, an experiment was conducted at research farm of ramin agricultural sciences and natural resources university. the experiment was arranged in split plots based on randomized complete block design with four replications. main pl...