Under relatively cool ambient temperatures and a caloric deficit, **** will undergo daily torpor - a short-term regulated reduction in metabolic rate with a concomitant drop in body temperature. **** can alternatively achieve metabolic savings by utilizing behavioral changes, such as seeking a warmer environment. However, there is a lack of knowledge about the behavioral interaction between torpor utilization and thermotaxis. That is, if a fasted mouse is faced with a choice between a warm environment not conducive for torpor, and a cool environment that will induce torpor, which scenario will the fasting mouse choose? Here, the temperature preferences of fasted **** were studied using a temperature gradient device that allows a mouse to freely move along a gradient of temperatures. C57BL/6 **** were implanted with temperature telemeters that recorded location, core temperature (Tb), and activity concurrently over a 23-h period in the thermal gradient. When the gradient was on, **** preferred the warm end of the gradient when fed (71 ± 4% of the time) and even more so when fasted (84 ± 2%). When the gradient was on, the fasted minimum Tb was significantly higher (34.4 ± 0.3 °C) than when the gradient was off (27.7 ± 1.6 °C). Further, fasted **** lost significantly more weight when the gradient was off despite maintenance of a metabolically favorable lower minimum Tb in this condition. These results indicate that fasted **** not only prefer warm ambient temperatures when given the choice, but that it is also the pathway with more favorable metabolic outcomes in a period of reduced caloric intake.The purpose of this study was to understand and discuss the relationships of the thermal environment, morphophysiological response, performance, and carcass traits of Brahman bulls from weaning at 18 months exposed to grazing conditions based on the physiological and evolutionary rationale behind the different proposals for the thermal adaptation of zebu cattle. Fifty-three uncastrated and clinically healthy bulls with birth and weaning weight of 34.0 ± 3.32 kg and 215.5 ± 44.75 kg, respectively, were evaluated. https://www.selleckchem.com/products/nedometinib.html Fifteen canonical correlations were estimated, but only six were significant thermal environment × thermoregulatory responses (rc = 0.4635; P = 0.0413); thermal environment × performance (rc = 0.4338; P = 0.0218); thermoregulatory responses × performance (rc = 0.5119; P = 0.0071); hair coat characteristics × performance (rc = 0.4939; P = 0.0273); hormone × carcass traits (rc = 0.5408; P = 0.0698); and performance × carcass traits (rc = 0.9644; P less then 0.0001). Thermal environment, thermoregulatory responses and hair coat morphology influence of 18.81%, 21.49% and 24.40%, respectively, were found in the performance. We also concluded that (i) rectal temperature (RT) is a homoeothermic indicator; (ii) sweating rate (SR) is an important heat dissipation mechanism to explain the adaptation of zebu animals in the tropics and is related to weight at 550 days (W550); (iii) coat morphology, especially length (HL), diameter (HD) and hair density (ND) are related to animal performance; and (iv) hormonal profile, mainly T4, influences the carcass traits (yield, weight, subcutaneous fat and marble meat).The purpose of this study is to develop a comprehensive thermodynamic model of the human respiratory system and quantify the effects of inspiratory air temperature, relative humidity (RH), lung capacity and O2 fluctuation in metabolic reaction on the human respiratory system under three different physiological conditions, i.e. rest, moderate level of physical activity and extreme level of physical activity. Therefore, a second law-based analysis has carried out for the human respiratory system. It is observed that exergetic efficiency decreases by 21% and 16.5% during moderate and extreme level of activity respectively as compared to the physical condition of rest. The respiratory efficiency also increases with the increase in inspiratory air temperature and RH. For a given inspiratory air temperature, an increase in lung volume leads to a reduction in the efficiency. Increase in TV with a high airflow rate gives a higher magnitude of efficiency, such a situation appearing when a person's lung compliance harmed due to diseases. The respiratory efficiency decreases up to 2% with the increase in O2 percentage. The efficiency of the respiratory system is in maximum during rest followed by an extreme and moderate level of activity. However, with the controlled supply of O2, the efficiency of the human respiratory performance increases with the decrease in O2 percentage. Due to partial oxidation of glucose at a reduced O2 level, exergy input from the metabolic reaction is less leading to increased exergetic efficiency.Motion Sickness is associated with a variety of symptoms, which differ in occurrence rate and intensity between individuals. In order to research the cause of car sickness and develop countermeasures, it is important to determine symptoms and their severity objectively. A tool for this purpose could be the assessment of physiological reactions due to motion sickness. This paper describes and discusses a methodology to identify changes in facial skin temperatures in a real-driving study. Common techniques had to be adjusted in order to meet the requirements given by the challenges of in-car-recording. The examined data was generated in a previous study, which was designed to research motion sickness in a driving environment. A pre-processing technique had to be developed to magnify features on the face and subsequently improve the tracking in thermal imagery. After the pre-processing, regions of interest (ROI) were manually marked and tracked in thermal images. The thereby assessed facial skin temperatures were compared to tympanic temperatures. Derived temperatures from the forehead as well as from the 20 hottest pixels within the face indicated a better tracking, while the nose tip was more affected by detection errors. The correlation of the three features with the tympanic temperature showed remarkable differences between a baseline measurement and the actual driving. Less than 10% of the data derived during the driving and up to 30% of the data during the baseline measurement correlated highly. It is concluded that detecting changes in facial skin temperature using thermal infrared imaging in a moving car is challenging and results are hardly comparable to tympanic temperatures. Future research should aim at the different influencing factors of skin and tympanic temperature, while enhancing tracking or detection of ROI could be achieved by reducing the passengers' movements or choosing the target area more carefully.
Under relatively cool ambient temperatures and a caloric deficit, mice will undergo daily torpor - a short-term regulated reduction in metabolic rate with a concomitant drop in body temperature. Mice can alternatively achieve metabolic savings by utilizing behavioral changes, such as seeking a warmer environment. However, there is a lack of knowledge about the behavioral interaction between torpor utilization and thermotaxis. That is, if a fasted mouse is faced with a choice between a warm environment not conducive for torpor, and a cool environment that will induce torpor, which scenario will the fasting mouse choose? Here, the temperature preferences of fasted mice were studied using a temperature gradient device that allows a mouse to freely move along a gradient of temperatures. C57BL/6 mice were implanted with temperature telemeters that recorded location, core temperature (Tb), and activity concurrently over a 23-h period in the thermal gradient. When the gradient was on, mice preferred the warm end of the gradient when fed (71 ± 4% of the time) and even more so when fasted (84 ± 2%). When the gradient was on, the fasted minimum Tb was significantly higher (34.4 ± 0.3 °C) than when the gradient was off (27.7 ± 1.6 °C). Further, fasted mice lost significantly more weight when the gradient was off despite maintenance of a metabolically favorable lower minimum Tb in this condition. These results indicate that fasted mice not only prefer warm ambient temperatures when given the choice, but that it is also the pathway with more favorable metabolic outcomes in a period of reduced caloric intake.The purpose of this study was to understand and discuss the relationships of the thermal environment, morphophysiological response, performance, and carcass traits of Brahman bulls from weaning at 18 months exposed to grazing conditions based on the physiological and evolutionary rationale behind the different proposals for the thermal adaptation of zebu cattle. Fifty-three uncastrated and clinically healthy bulls with birth and weaning weight of 34.0 ± 3.32 kg and 215.5 ± 44.75 kg, respectively, were evaluated. https://www.selleckchem.com/products/nedometinib.html Fifteen canonical correlations were estimated, but only six were significant thermal environment × thermoregulatory responses (rc = 0.4635; P = 0.0413); thermal environment × performance (rc = 0.4338; P = 0.0218); thermoregulatory responses × performance (rc = 0.5119; P = 0.0071); hair coat characteristics × performance (rc = 0.4939; P = 0.0273); hormone × carcass traits (rc = 0.5408; P = 0.0698); and performance × carcass traits (rc = 0.9644; P less then 0.0001). Thermal environment, thermoregulatory responses and hair coat morphology influence of 18.81%, 21.49% and 24.40%, respectively, were found in the performance. We also concluded that (i) rectal temperature (RT) is a homoeothermic indicator; (ii) sweating rate (SR) is an important heat dissipation mechanism to explain the adaptation of zebu animals in the tropics and is related to weight at 550 days (W550); (iii) coat morphology, especially length (HL), diameter (HD) and hair density (ND) are related to animal performance; and (iv) hormonal profile, mainly T4, influences the carcass traits (yield, weight, subcutaneous fat and marble meat).The purpose of this study is to develop a comprehensive thermodynamic model of the human respiratory system and quantify the effects of inspiratory air temperature, relative humidity (RH), lung capacity and O2 fluctuation in metabolic reaction on the human respiratory system under three different physiological conditions, i.e. rest, moderate level of physical activity and extreme level of physical activity. Therefore, a second law-based analysis has carried out for the human respiratory system. It is observed that exergetic efficiency decreases by 21% and 16.5% during moderate and extreme level of activity respectively as compared to the physical condition of rest. The respiratory efficiency also increases with the increase in inspiratory air temperature and RH. For a given inspiratory air temperature, an increase in lung volume leads to a reduction in the efficiency. Increase in TV with a high airflow rate gives a higher magnitude of efficiency, such a situation appearing when a person's lung compliance harmed due to diseases. The respiratory efficiency decreases up to 2% with the increase in O2 percentage. The efficiency of the respiratory system is in maximum during rest followed by an extreme and moderate level of activity. However, with the controlled supply of O2, the efficiency of the human respiratory performance increases with the decrease in O2 percentage. Due to partial oxidation of glucose at a reduced O2 level, exergy input from the metabolic reaction is less leading to increased exergetic efficiency.Motion Sickness is associated with a variety of symptoms, which differ in occurrence rate and intensity between individuals. In order to research the cause of car sickness and develop countermeasures, it is important to determine symptoms and their severity objectively. A tool for this purpose could be the assessment of physiological reactions due to motion sickness. This paper describes and discusses a methodology to identify changes in facial skin temperatures in a real-driving study. Common techniques had to be adjusted in order to meet the requirements given by the challenges of in-car-recording. The examined data was generated in a previous study, which was designed to research motion sickness in a driving environment. A pre-processing technique had to be developed to magnify features on the face and subsequently improve the tracking in thermal imagery. After the pre-processing, regions of interest (ROI) were manually marked and tracked in thermal images. The thereby assessed facial skin temperatures were compared to tympanic temperatures. Derived temperatures from the forehead as well as from the 20 hottest pixels within the face indicated a better tracking, while the nose tip was more affected by detection errors. The correlation of the three features with the tympanic temperature showed remarkable differences between a baseline measurement and the actual driving. Less than 10% of the data derived during the driving and up to 30% of the data during the baseline measurement correlated highly. It is concluded that detecting changes in facial skin temperature using thermal infrared imaging in a moving car is challenging and results are hardly comparable to tympanic temperatures. Future research should aim at the different influencing factors of skin and tympanic temperature, while enhancing tracking or detection of ROI could be achieved by reducing the passengers' movements or choosing the target area more carefully.
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