Literatura académica sobre el tema "Thermal physiological responses"
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Artículos de revistas sobre el tema "Thermal physiological responses":
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Zhong, Xianzhun, Hang Yu, Yin Tang, Huice Mao y Kege Zhang. "Local Thermal Comfort and Physiological Responses in Uniform Environments". Buildings 14, n.º 1 (24 de diciembre de 2023): 59. http://dx.doi.org/10.3390/buildings14010059.
Resumen
The thermal perception of different body parts can vary greatly throughout the human body and have different influences on overall thermal sensation and comfort. Various personal comfort systems (PCS) have been developed to stimulate local body parts for the purpose of enhancing human thermal comfort, yet the most effective body parts for intervention remain undetermined. Therefore, a series of climate chamber experiments under five uniform environments with three sets of suits were conducted in this study. The results showed that the head, chest, belly, and hands tended to feel no cooler than overall in cooler environments, but arms and legs felt generally no warmer than overall in warmer environments. The head, trunk and upper arms were more likely to be the comfort-dominant body parts. Additionally, the upper arms and upper back expected temperature regulation measures the most under non-neutral environments, thus they seem to be the two most needed and effective targeted body parts that a PCS could be applied to. The skin temperature and thermal sensation of limbs were more sensitive to indoor air temperatures than those of the torso. However, variations in the skin temperature of the head, chest, upper back, and calves had the strongest correlation with overall sensation vote changes. The above results and conclusions can not only serve as the basis for the future studies of local thermal comfort, but also provide theoretical guidance for the design of future PCS products.
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Zhu, Hui, Linsheng Huang, Chuck Wah Francis Yu y Hua Su. "Thermal comfort under weightlessness: A physiological prediction". Indoor and Built Environment 29, n.º 8 (12 de julio de 2020): 1169–80. http://dx.doi.org/10.1177/1420326x20935279.
Resumen
This study investigated the physiological thermal response of people under simulated weightlessness using a 6° head down bed rest (HDBR) model to ensure the human body functions in the weightlessness way. Thermal responses of six male participants were experimentally determined. The relationship between thermal comfort and heart rate variability (HRV) was also scrutinized. Physiological responses of participants under different environmental conditions were observed including core temperature, sweating, and most importantly, HRV. Elevated core temperatures were observed amongst participants, with a maximum increment of 0.5°C. The sweating of participants under simulated weightlessness was conspicuously retarded, requiring a 2–4°C increase in environmental temperature to start sweating. Body regional differences in the sweating were also observed. The HRV index ‘LF/HF’, which reflects the balance of the autonomous nervous system, was found to vary with the environment and closely associated with the variation in the thermal comfort scores. Participants under simulated weightlessness had higher mean LF/HF when they felt comfortable, and they preferred a warmer environment in comparison to under normal gravity condition. An altered thermoregulation of the human body under simulated weightlessness was indicated by our findings. The use of HRV index could provide a useful prediction of subjective thermal comfort under weightlessness.
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Klous, L., A. Psikuta, K. Gijsbertse, D. Mol, M. van Schaik, H. A. M. Daanen y B. R. M. Kingma. "Two isothermal challenges yield comparable physiological and subjective responses". European Journal of Applied Physiology 120, n.º 12 (20 de septiembre de 2020): 2761–72. http://dx.doi.org/10.1007/s00421-020-04494-3.
Resumen
Abstract Purpose Ventilated vests are developed to reduce thermal stress by enhancing convective and evaporative cooling from skin tissue underneath the vest. The purpose of this study is to investigate whether thermal stress is equal when a ventilated vest is worn compared to a no-vest situation with similar dry thermal resistance. Methods Nine healthy males walked on a treadmill (7 km h−1) for 45 min in a desert climate (34 °C, 20% relative humidity) with and without ventilated vest. Gastrointestinal temperature (Tgi), heart rate (HR), and skin temperature (Tsk) were continuously monitored. Local sweat rate (LSR) was assessed two times on six skin locations. Subjective ratings were assessed every 10 min. Results Final Tgi (37.6 ± 0.1 °C for vest and 37.6 ± 0.1 °C for no-vest), HR (133 ± 7 bpm and 133 ± 9 bpm) and mean Tsk (34.8 ± 0.7 °C and 34.9 ± 0.6 °C) were not different between conditions (p ≥ 0.163). Scapula skin temperature (Tscapula) under the vest tended to be lower (baseline to final: ΔTscapula = 0.35 ± 0.37 °C) than without vest (ΔTscapula = 0.74 ± 0.62 °C, p = 0.096). LSR at locations outside the vest did not differ with and without vest (p ≥ 0.271). Likewise, subjective responses did not differ between conditions (χ2 ≥ 0.143). Conclusions We conclude that two systems with similar dry thermal resistance and, therefore, similar required evaporation, resulted in similar thermal stress during paced walking in a hot-dry environment. Local ventilation did not alter the sweating response on locations outside the vest.
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Eglin, Clare M. "Physiological Responses to Fire-fighting: thermal and Metabolic Considerations". Journal of the Human-Environment System 10, n.º 1 (2007): 7–18. http://dx.doi.org/10.1618/jhes.10.7.
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Ying, B. A., Y. L. Kwok, Y. Li, C. Y. Yeung, F. Z. Li y S. Li. "Mathematical modeling of thermal physiological responses of clothed infants". Journal of Thermal Biology 29, n.º 7-8 (octubre de 2004): 559–65. http://dx.doi.org/10.1016/j.jtherbio.2004.08.027.
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Curio, Immo. "Physiological responses during magnitude estimation of thermal nociceptive stimuli". International Journal of Psychophysiology 7, n.º 2-4 (agosto de 1989): 168–69. http://dx.doi.org/10.1016/0167-8760(89)90115-3.
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Salachan, Paul Vinu, Jesper Givskov Sørensen y Heidi Joan Maclean. "What can physiological capacity and behavioural choice tell us about thermal adaptation?" Biological Journal of the Linnean Society 132, n.º 1 (10 de noviembre de 2020): 44–52. http://dx.doi.org/10.1093/biolinnean/blaa155.
Resumen
Abstract To date, behavioural responses and their role in thermal adaptation have largely been overlooked in small ectotherms. Here, we measure reproductive output using four adult acclimation temperatures in Drosophila melanogaster and quantify egg-laying at restricted temperatures (thermal capacity) and across a thermal gradient (thermal preference). We demonstrate that different conclusions about insect responses to changing environmental temperatures can be drawn based on whether individuals are temperature restricted or allowed a behavioural choice of temperature. When measuring physiological capacity at forced temperatures, we find an acclimation response to increasing temperatures. In contrast, when measuring behavioural choice, we find limited variation in thermal preference regardless of the acclimation temperature. Although flies are physiologically capable of increased performance at higher temperatures, these benefits might not be realized in heterogeneous environments. Our data serve as an example to illustrate why it is important to understand how behaviour and physiology contribute to thermal biology and, ultimately, the ecology of organisms. To do this, we should consider the behavioural avenues available to the organism when estimating ecologically relevant fitness consequences in varying thermal environments.
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Tunnah, Louise, Suzanne Currie y Tyson J. MacCormack. "Do prior diel thermal cycles influence the physiological response of Atlantic salmon (Salmo salar) to subsequent heat stress?" Canadian Journal of Fisheries and Aquatic Sciences 74, n.º 1 (enero de 2017): 127–39. http://dx.doi.org/10.1139/cjfas-2016-0157.
Resumen
We designed two environmentally relevant thermal cycling regimes using monitoring data from an Atlantic salmon (Salmo salar) river to determine whether exposure to prior diel cycles stimulated protective mechanisms (e.g., heat hardening) and (or) resulted in physiological and cellular stress. Wild fish were exposed to 3 days of diel cycling in the lab and then exposed to an acute thermal challenge near their upper reported critical temperature. We measured routine metabolic rate across the time course as well as indicators of physiological status (e.g., plasma glucose and osmolality) and cellular stress (e.g., heat shock protein 70). We observed that thermal cycling altered physiological and cellular responses, compared with an acute heat shock, but saw no differences between cycling regimes. Unique temperature regime and tissue-specific responses were observed in heat shock protein induction, metabolites, haematology, and osmotic indicators. Routine metabolic rate was not affected by the thermal cycling and increased according to Q10 predictions. While we report unique physiological and cellular responses among all treatment groups, we did not observe a clear indication of a heat hardening response.
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Zlatar, Tomi, Denisse Bustos, José Torres Costa, João Santos Baptista y Joana Guedes. "Physiological and Thermal Sensation Responses to Severe Cold Exposure (−20 °C)". Safety 10, n.º 1 (12 de febrero de 2024): 19. http://dx.doi.org/10.3390/safety10010019.
Resumen
Various jobs, indoors and outdoors, are subjected to severe cold temperatures during daily activities. Extremely low-temperature exposure and work intensity affect health, safety, and occupational performance. This work aimed to assess the physiological and thermal sensation responses before, during, and following a 60 min exposure to cold (−20 °C), during which occupational activities were developed. Using ingestible telemetric temperature pills, eight skin temperature sensors, blood pressure equipment, and the Thermal Sensation Questionnaire, experiments were conducted with 11 healthy male volunteers wearing highly insulating cold protective clothing. The most notorious alterations were reported in mean skin temperatures and thermal sensation responses during the first 20 min of cold exposure. Among the eight skin temperature points, the forehead and left hand showed a higher sensitivity to cold. The mean core temperature reported significant variations throughout the protocol, with decreases during the initial 10 min of cold exposure and posterior increases despite the cold environment. Blood pressure showed slight increases from the initial to the recovery period. Overall, outcomes contribute to current scientific knowledge on physiological and perception responses in extremely cold environments while describing the influence of protective clothing and occupational activities on these responses. Future research should be developed with additional skin temperature measurements in the extremities (fingers, face, and toes) and the analysis of thermal sensation potential associations with performance changes, which can also be of great significance for future thermal comfort models.
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Gupta, Mahesh, Sachin Kumar, S. Dangi y Babu Jangir. "Physiological, Biochemical and Molecular Responses to Thermal Stress in Goats". International Journal of Livestock Research 3, n.º 2 (2013): 27. http://dx.doi.org/10.5455/ijlr.20130502081121.
Tesis sobre el tema "Thermal physiological responses":
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Lewis, Stella Anne. "Physiological and cellular level responses of Enteromorpha spp. to chemical and thermal stress". Thesis, University of Plymouth, 1998. http://hdl.handle.net/10026.1/2147.
Resumen
The aims of this project were to investigate the cellular stress response (CSR) in Enteromorpha spp. and assess the potential of the Stress-70 protein (an indicator of the CSR) as a biomarker of pollutant exposure and acquired tolerance in Enteromorpha spp., compared with conventional physiological endpoints of toxicity. Cross-reactivity of a commercial Stress-70 antibody with E. intestinalis proteins was determined and used to develop an assay for Stress-70. Using this assay E. intestinalis was found to exhibit a typical heat shock response. Stress-70 proved to be a relatively insensitive biomarker of copper exposure and did not appear to be involved in copper tolerance, the genetic basis of which was investigated by growing E. intestinalis using a novel culturing technique. Although growth was variable, it provided a simple, consistent and sensitive measure of copper toxicity. The chlorophyll fluorescence parameter Fv/Fm was insensitive to copper exposure. Nutrient limitation enhanced copper toxicity and significantly impaired growth, Fv/Fm and Stress-70 production in E. intestinalis. In both copper ‘sensitive’ and ‘tolerant’ E. intestinalis, copper exposure did not affect the ability to raise a heat shock response. In ‘sensitive’ algae, copper and heat shock were additive stressors, with heat shock acting as a stronger inducer of Stress-70. Only heat shock affected 'tolerant' algae. Zinc was less toxic than copper but in contrast to copper studies, Stress-70 was a relatively sensitive indicator of zinc exposure, compared to Fv/Fm and growth. Studies of triazine herbicides revealed that on a molarity basis, Irgarol 1051 was more toxic to E. intestinalis than atrazine. Fv/Fm and growth were strongly affected by Irgarol exposure, but Stress-70 levels were unaltered by exposure to the herbicide. Fv/Fm and Stress-70 were poor in situ biomarkers of pollution, but another chlorophyll fluorescence parameter - complementary area - appeared to correlate with levels of organic pollution. Overall, Stress-70 was found not to be a useful biomarker of exposure to copper or triazines in E. intestinalis, or in situ pollution. However, the Stress-70 assay developed has a number of alternative applications and Enteromorpha spp. were deemed to be potentially useful in pollution monitoring with the selection of suitable biomarker responses.
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Basson, Christine Helene. "Thermal adaptation in the lizard Cordylus oelofseni : physiological and behavioural responses to temperature variation". Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/95471.
Resumen
Thesis (MSc)--Stellenbosch University, 2013.ENGLISH ABSTRACT: As ectotherms, lizards are particularly vulnerable to changes in the thermal landscape and face extinction risk if they lack the capacity to rapidly adapt or behaviourally mitigate increasingly altered thermal environments. Theoretical models that predict lizards‟ response to climate change often fail to take into account the thermal characteristics of the microenvironment, the ability of lizards to behaviourally buffer climate variation in the habitat and the plastic nature of both behaviour and physiology over ecologically relevant time-scales. Here, I address this major knowledge gap using two separate research chapters in an experimental physiology approach. In Chapter 1, I investigated the temperature-dependence and plasticity of resting metabolic rate, water-loss rate and preferred body temperature of Cordylus oelofseni at several temporal scales (within and between seasons) and incorporated field observations to acquire a better understanding of this species‟ adaptive potential to buffer thermal changes in the habitat. Cordylus oelofseni showed plasticity of both behaviour and physiology in response to thermal acclimation, but relied on distinct strategies depending on the time-scale investigated. These results highlighted the complexity of underlying mechanisms used by these organisms to buffer temperature variation. In Chapter 2, I used an experimental approach to examine the energetic costs of thermoregulation in C. oelofseni and test the cost-benefit model of thermoregulation. This model‟s primary prediction states that lizards should thermoregulate carefully only when the associated costs are low. Using four enclosures that simulated different thermal qualities (temporal and spatial distributions of operative temperatures) in the habitat, I found limited support for the cost-benefit model. Lizards in the low-quality heterogeneous enclosures invested the same energetic effort and thermoregulated with similar overall accuracy as lizards in the high-quality heterogeneous enclosure. The costs incurred were not necessarily energetic, but reflected missed opportunities (e.g. less time to forage), something that, along with important interaction effects with body mass, deserves further attention when testing this model. Together, these results illustrate the importance of incorporating ecological reality at various time and spatial scales in order to make relevant predictions regarding the fate of lizards with projected climate change.
AFRIKAANSE OPSOMMING: As ektotermiese diere, is akkedisse veral sensitief vir veranderinge in die termiese landskap en staar uitsterwingsrisiko in die gesig as hulle nie die vermoë het om vinnig aan te pas of gedragsveranderinge te maak in omgewings wat toenemend verwarm nie. Teoretiese modelle wat akkedisse se reaksie op klimaatsverandering voorspel, neem dikwels nie die termiese eienskappe van die mikro-omgewing, die vermoë van akkedisse om met gedragsveranderinge klimaat variasie in die habitat te buffer en die plastieke aard van beide gedrag en fisiologie oor ekologies relevante tydskale in ag nie. Hier bespreek ek hierdie groot kennisgaping met behulp van twee afsonderlike navorsingshoofstukke in 'n eksperimentele fisiologie benadering. In Hoofstuk 1 het ek ondersoek ingestel na die temperatuur-afhanklikheid en plastisiteit van rustende metaboliese tempo, waterverlies tempo en voorkeur liggaamstemperatuur van Cordylus oelofseni by verskeie tydskale (binne en tussen seisoene) en inkorporeer veld waarnemings om 'n beter begrip te verkry van hierdie spesie se aanpasbare potensiaal om termiese veranderinge in die habitat te buffer. Cordylus oelofseni het plastisiteit van beide gedrag en fisiologie in reaksie op hitte-akklimatisering getoon, maar staatgemaak op verskillende strategieë, afhangende van die tyd-skaal wat ondersoek is. Hierdie resultate beklemtoon die kompleksiteit van die onderliggende meganismes wat gebruik word deur hierdie organisme om temperatuur verandering te buffer. In Hoofstuk 2 het ek 'n eksperimentele benadering gebruik om die energiekoste van termoregulering in C. oelofseni te ondersoek en die kostevoordeel model van termoregulering te toets. Hierdie model se primêre voorspelling verklaar dat akkedisse slegs versigtig moet termoreguleer wanneer die gepaardgaande koste laag is. Deur gebruik te maak van vier afskortings wat verskillende termiese eienskappe gesimuleer het (tyd en ruimtelike verspreiding van operatiewe temperature) in die habitat, het ek beperkte ondersteuning gevind vir die koste-voordeel model. Akkedisse in die lae-gehalte heterogene afskortings het dieselfde energieke moeite belê en getermoreguleer met soortgelyke algehele akkuraatheid as akkedisse in die hoë-gehalte heterogene kamp. Die kostes wat aangegaan is, is nie noodwendig energiek nie, maar weerspieël geleenthede wat gemis is (bv. minder tyd om kos te soek), iets wat, saam met belangrike interaksie effekte met liggaamsmassa, verdere aandag verdien wanneer hierdie model getoets word. Tesame illustreer hierdie resultate die belangrikheid van die integrasie van ekologiese werklikheid op verskillende tyd en ruimtelike skale, om relevante voorspellings oor die lot van akkedisse met geprojekteerde klimaatsverandering te kan maak.
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Barwood, Martin James. "Psychophysiology of survival : the impact of psychological strategies on the physiological responses to thermal environments". Thesis, University of Portsmouth, 2005. https://researchportal.port.ac.uk/portal/en/theses/psychophysiology-of-survival(5abcbf6a-c797-468f-bbf2-3a62e999d79d).html.
Resumen
The work described in this thesis was conducted to assess the contribution psychological skills training (PST) including goal-setting, relaxation strategies, mental imagery and positive self-talk, can make to the capability to suppress or tolerate the physiological responses to thermally stressful environments. PST, a technique originally developed in sport psychology studies, was specifically tailored to aid individuals in adverse conditions, thereby providing some insight in to the contribution psychological factors can make to survival. This approach was designed to provide some idea of the contribution the will to survive may make in hazardous and threatening circumstances. We hypothesised that psychological training could significantly alter the responses elicited by thermal stimuli. The assumption was that psychological skills that have proven to be efficacious under psychological and physiological stress in challenging sporting environments, could also prove influential in more hazardous thermal environments. Study I examined the influence of mental imagery on the vasomotor responses to thermoneutral (26-28°C), cool (12.5°C) and warm (40°C) air in twelve healthy male subjects. We assessed whether hot and cold mental images could alter peripheral vasomotor tone and thermal perception in these environments. This study was conducted to quantify the influence of a psychological skill whilst at rest and in an environment with few external stimuli. Comparisons between control and mental imagery periods (hot and cold), both before and after mental imagery training, suggested that a single psychological skill has a limited capacity to alter the largely involuntary vasomotor responses to thermoneutral, cool, and warm air as only transient and insignificant effects were observed. There is also only a limited impact of this type of mental practice on thermal perception in a thermoneutral (26-28°C) environment. The null hypothesis was therefore accepted. The subsequent study (study 2) examined the impact of a package of psychological skills on the responses that are recognised as being under greater voluntary control at rest, but have been thought to be involuntary following acute cold-water stimulation, namely breath-holding. This study involved 32 healthy male subjects completing two immersions into cold-water (I VC), an activity that significantly reduces maximal breath-hold time and that can be a precursor to drowning following accidental immersion. On immersion the subjects were required to breath-hold for as long as possible. Following an initial breath-hold immersion subjects were ranked in order of lowest to highest breath-hold time (BHwater,), and allocated to either a control group (CG: BRm, r time mean [s. d]; n= 16: 24.01 [6.72] sec) or a psychological intervention group (PIG: n= 16: 24.66 [14.60] sec). Over the 7-day period between immersions the CG continued normal daily activity whereas the PIG completed five 1-hour PST sessions comprising goal-setting, relaxation strategies, mental imagery and positive self-talk; the final session provided a summary of the first 4 skills. Subjects then completed a second breath-hold immersion during which the PIG recorded a significantly longer breath-hold time after psychological intervention compared to the CG (BHwater4: 4.25 [31.63] sec; CG: 21.34 [16.3 1 ]; P=0.026). PST conferred an almost 80% improvement in BHwater suggesting psychological factors may significantly influence the respiratory responses to cold-water immersion providing the first indication of the influence of mental 'will' in such conditions. Study 3 examined the impact of PST on maximal BHwater following coldhabituation, thus assessing the extent to which habituation to cold water includes a conscious psychological component. Twenty healthy, non-habituated male subjects completed an initial immersion into cold-water (I2°C whilst breath-holding (BHwater) and were subsequently matched and allocated to one of two groups, a habituation only group (HAB, n= 10: BHwater22.00 [10.33] sec) and a habituation plus PST group (H-PST, n= 10: 22.38 [10.65]sec). In the interim period (7-10 days) between breath-hold immersions all subjects completed 5 free breathing immersions into cold-water (12°C). In addition, the H-PST group completed the same PST intervention as used in study 2, aimed at consciously increasing maximal BHwater time on immersion. After their respective interventions all subjects completed a second breath-hold immersion. Results showed that the habituation regimen significantly reduced the cardiorespiratory responses to immersion in both groups by a similar magnitude. Significant changes took place in both groups by the 4th habituation immersion. Statisicial analysis showed no significant differences between groups in BHwater (P = 0.299) indicating PST did not have a significant and additive effect upon the ability to breath-hold on immersion after habituation (HAB, n= 10:BHwater 36.31 [23.88] sec; H-PST, n= 10: 49.25 [30.87]). Study 4 examined the influence of a PST package on the voluntarybehavioural responses to prolonged thermal stress whilst exercising (30°C for 90minutes). Eighteen subjects completed a total of 3 exercise trials in the heat in whichthey were required to run as far as possible on a treadmill until exhaustion occurred,or the allotted time expired. Following trial 2 subjects were matched and allocated toeither a CG or PIG based on the variability in run performance shown between trial Iand 2. The groups alos did not significantly differ based on maximal oxygen uptake,or sum of skinfold (s. o. s) measurement but were not matched on these criteria. As with study 2, the CG continued normal daily activity between trials 2 and 3 whereas the PIG completed a version of the previously used PST package tailored to help them cope with the unpleasant sensations associated with elevated deep body temperature and prolonged exercise in the heat. Inter-trial variability was 1.70 [2.82]% between trial I and 2 in the CG versus 0.98% [5.28] in the PIG. Between trial 2 and 3 the CG improved by 2.74% [4.03] whereas the PIG ran 6.88% [5.82] further in trial 3. In percentage terms, the PIG ran significantly further in trial 3. The mechanism underpinning the change in performance in the PIG was not statistically linked to any of the physiological variables measured. Overall, the findings suggest PST may also influence the capacity to tolerate the unpleasant physiological responses to exercise in the heat, but were less influential than in the cold. The possible mechanisms underpinning the changes that take place with PSTare considered. It is concluded that psychological skills training significantlyinfluenced the physiological responses over which there is greatest voluntary controlThe present work demonstrates the potential role psychological factors may play in surviving certain conditions and scenarios which involve the choice to tolerate or suppress the evoked responses to thermal stimuli or, to succumb to the environmental conditions. The distinction between individuals in making this choice may be a product of mental will and provides the first evidence that the will to survive may have some genuine foundation between being a victim or a survivor following accidental exposure.
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Yanagi, Junior Tadayuki. "Partial surface wetting to relieve acute thermal stress of laying hens". Universidade Federal de Viçosa, 2002. http://www.locus.ufv.br/handle/123456789/11515.
Resumen
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Um sistema de medição e controle foi desenvolvido para o estudo de respostas fisiológicas de aves sujeitas a mudanças térmicas como meio de alívio de estresse térmico. O sistema faz o controle automático da temperatura (t a,SP ±0,2 oC) e da umidade relativa do ar (RH SP ±2 %); sendo que a velocidade do ar foi controlada manualmente (V SP ±0,1 m· s -1 ); e contínuo armazenamento das termografias (ex., temperatura superficial, t surf ) e da temperatura corporais (t b ) dos animais. As condições térmicas controladas na zona de ocupação animal (AZO) são atingidas pela operação de um pequeno túnel de vento (V = 0 to 1,5 m· s -1 ) colocado no interior de uma sala ambiental com t a e RH controlados (5,0 m comprimento × 3,5 m largura × 3,0 m altura). Os valores desejados de t a e RH foram alcançados por meio de aquecedores e umidificadores controlados em dois estágios via um módulo de controle e medição programável, e periféricos. Termografias (discernabilidade de 0.06°C) são adquiridas com uma camera infravermelho cuja operação é controlada remotamente por um PC. t b (±0.1°C) é armazenado em uma unidade de telemetria, sem a necessidade de intervenção cirurgica, que também é conectado a um PC. Em adição, um sistema de video tem sido usado para observar e arquivar os comportamentos do animal. A instrumentação desenvolvida foi usada em um experimento para ajustar equações empíricas para descrever as necessidades de molhamento parcial da superfície em galinhas poedeiras (Hy-Line W98, com 34 ± 1 semanas) sujeitas a condições de estresse térmico. A água necessária para limitar o aumento da temperatura superficial das galinhas foi expressada em termos de intervalo de aspersão (SI 10 , min) para uma dosagem constante (10 ml· aspersão -1 ) ou para uma taxa de evaporação (ER, ml.min -1 ) de água aspergida. As exposições térmicas consistiram de uma combinação fatorial de 3 temperaturas de bulbo seco (t db ) (35, 38 e 41 °C) x 2 temperaturas de ponto de orvalho (t dp ) (21,1 e 26,7 °C) x 3 velocidades do ar (V) (0,2, 0,7 e 1,2 m· s -1 ). As condições ambientais foram expressas como 18 combinações de déficit de vapor de pressão do ar (VPD air ) x V. ER foi diretamente proporcional ao produto VPD air · V . As relações podem servir como a base para a otimizar o sistema de resfriamento superficial intermitente para alívio de estresse térmico em galinhas criadas em gaiolas. Ademais, um índice de desconforto térmico (TDI) foi derivado com base nas respostas fisiológicas, temperatura superficial (t surf ) e temperatura corporal (t b ), de galinhas sujeitas a exposições térmicas. Com base no aumento da t b aos 50 min de exposição térmica (Δt b,50 ), um TDI foi relacionado ao VPD air e a V da seguinte forma: TDI = -15.17 + 18.62 (t db ) n – 0.92 · (VPD air · V ) n . Usando TDI, quatro zonas de desconforto térmico (segura, alerta, perigo e fatal) foram definidas para as várias combinações de condições térmicas. Um modelo teórico de transferência de calor e massa em regime transiente também foi proposto para predizer Δt b,50 em função das condições ambientais, das condições fisiológicas das aves e do nível de molhamento (β). O modelo proporciona uma ferramenta conveniente e interativa para determinar Δt b,50 nas galinhas submetidas ou não ao molhamento superficial para t db variando de 35 a 38 °C.
A control and measurement system was developed for studying physiological responses of poultry to thermal challenges and means of thermal stress relief. The system features automatic control of air temperature (t a,SP ±0.2 oC) and relative humidity (RH SP ± 2 %); manual setting of air velocity (V SP ± 0.1 m· s -1 ); and continuous recording of thermographs (i.e., core body temperature (t b ) of the animal. surface temperature, t surf ) and The controlled thermal conditions in the animal-occupied zone (AOZ) are achieved through operation of a small wind tunnel (V = 0 to 1.5 m· s -1 ) inside a t a - and RH-controlled environmental room (5 m L × 3.5 m W × 3.0 m H). Target t a and RH values are achieved by controlling auxiliary heaters and humidifiers in two stages via a programmable measurement and control module and peripherals. Thermographs (0.06°C discernability) are acquired with an infrared (IR) imager whose operation is remotely controlled by a PC. Core body temperature (t b , ±0.1°C) is recorded with a surgery-free telemetric sensing unit that is also interfaced with a PC. In addition, a video monitoring system is used to observe and archive animal behaviors. The instrumentation developed was used in an experiment to establish empirical equations to describe the need of partial surface wetting for cooling laying hens (Hy-Line W-98, 34 ±1 wk old) subjected to a range of thermal stress conditions. The thermal exposures consisted of a factorial combination of 3 dry bulb temperatures (t db ) (35, 38 and 41 °C) × 2 dew point temperatures (t dp ) (21.1 and 26.7 ° C) × 3 air velocities (V) (0.2, 0.7 and 1.2 m· s - ). The environmental conditions were expressed as 18 combinations of air vapor pressure deficit (VPD air ) × V. The water necessary to limit hen surface temperature from rising was expressed in terms of sprinkle interval (SI 10 , min) for a constant spray dosage (10 ml· spray -1 ) or evaporation rate (ER, ml· min -1 ) of the sprayed water. ER was directly proportional to VPD air · V . The relationships may serve as the basis for optimizing an intermittent partial surface cooling system for thermal stress relief of caged layers. Also from the study, a thermal discomfort index (TDI) was derived based on physiological responses, surface temperature (t surf ) and core body temperature (t b ) of the control (non-cooled) hens. Based on t b rise after 50 min of thermal exposure (Δt b,50 ), TDI related to VPD air and V as: TDI = -15.17 + 18.62 (t db ) n – 0.92· (VPD air · was V ) n . Using TDI, four zones of thermal discomfort (safe, alert, danger, and fatal) were defined for various combinations of thermal conditions. Furthermore, theoretical transient heat and mass transfer model was proposed to predict Δt b,50 as a function of environmental conditions, physiological responses of the hens and surface wetness level (β). The model provides a convenient, interactive tool for determining Δt b,50 on wetted and non-wetted hens for t db ranging from 35 to 38 °C.
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Gerrett, Nicola. "Body mapping of perceptual responses to sweat and warm stimuli and their relation to physiological parameters". Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/11000.
Resumen
Regional differences in sweat gland output, skin temperature and thermoreceptor distribution can account for variations in regional perceptions of temperature, thermal comfort and wetness sensation. Large cohorts of studies have assessed these perceptual responses during sedentary activity but the findings are typically applied to a multitude of conditions, including exercise. Increases in sweat gland output, redistribution of blood flow and changes in skin and core temperature are basic responses to exercise in most conditions and these ultimately influence our perceptual responses. The primary aim of this thesis is to determine factors that influence regional differences in thermal sensation, thermal comfort and wetness sensation during exercise in moderate to hot conditions. The secondary aim is to develop and understand an additional variable, galvanic skin conductance (GSC) that can be used to predict thermal comfort and wetness sensation. The aim of the first study (Chapter 4) was to determine the influence of exercise on thermal sensitivity and magnitude sensation of warmth to a hot-dry stimulus (thermal probe at 40°C) and assess if any gender-linked differences and/or regional differences exist. From the data, body maps indicating sensitivity were produced for both genders during rest and exercise. Females had more regional differences than males. Overall sensitivity was greatest at the head, then the torso and declined towards the extremities. The data showed that exercise did not cause a significant reduction in thermal sensitivity but magnitude estimation was significantly lower after exercise for males and selected locations in females. The cause of a reduced magnitude sensation is thought to be associated with exercise induced analgesia; a reduction in sensitivity due to exercise related increases in circulating hormones. As the literature suggests that thermal comfort in the heat is influenced by the presence of sweat, the next study and all proceeding studies were concerned with this concept. In Chapter 5, building on earlier studies performed in our laboratories, the influence of local skin wettedness (wlocal) on local thermal comfort and wetness sensation was investigated in a neutral dry condition (20.2 ± 0.5°C and 43.5 ± 4.5% RH) whilst walking (4.5 km∙hr-1). Regional differences in wlocal were manipulated using specialised clothing comprising permeable and impermeable material areas. Strong correlations existed between local thermal comfort and local wetness sensation with the various measured wlocal (r2>0.88, p<0.05 and r2>0.83, p<0.05, respectively). The thermal comfort limit was defined as the wlocal value at which the participants no longer felt comfortable. Regional comfort limits for wlocal were identified (in order of high-low sensitivity); lower back (0.40), upper legs (0.44), lower legs (0.45), abdomen (0.45), chest (0.55), upper back (0.56), upper arms (0.57) and lower arms (0.65). The maximum degree of discomfort and wetness sensation experienced during the investigation was kept deliberately low in an attempt to determine the threshold values. Therefore comfort scores and wetness scores rarely reached a state of uncomfortable or wet so the next step was to assess these relationships when sweat production is high and the sensations worsened. However, pilot testing indicated that a ceiling effect would occur for wlocal at high levels of sweat production whilst thermal discomfort increased indicating wlocal was not the determining parameter in that case. Thus an additional parameter was required. The chosen parameter was galvanic skin conductance (GSC) due to its alleged ability to monitor pre-secretory sweat gland activity, skin hydration and surface sweat. In Chapter 6, the reliability, reproducibility and validity of GSC were confirmed in a series of pilot tests. Moderate to strong correlations were found between GSC and regional sweat rate (RSR) (r2>0.60, p<0.05) and wlocal (r2>0.55, p<0.05). The literature suggests standardising GSC relative to a minimum and maximum GSC value; however uncertainties arise when attempting to achieve maximum GSC. Therefore a change from baseline (∆GSC) was chosen as the proposed method of standardisation for further use. Additional results (from Chapter 9) revealed that ∆GSC also reflects pre-secretory sweat gland activity as it increased prior to sweat being present on the skin surface and prior to an increase in RSR. In Chapter 9, also hydration of the stratum corneum was measured using a moisture meter and the results revealed that it has an upper limit; indicating maximal hydration. From this point of full skin saturation ∆GSC and RSR markedly increase though sensations did not. It was also found that ∆GSC is only influenced by surface sweat that is in direct contact with the electrode and is not influenced by sweat elsewhere on the skin surface between electrodes. Higher levels of thermal discomfort have rarely been explored and neither has its relationship with wlocal. The ability of ∆GSC and wlocal to predict local thermal comfort and wetness sensation were compared in two different conditions to elicit low and high sweat production. Unlike Chapter 5, the body sites were not manipulated to control wlocal but allowed to vary naturally over time. The test was carried out on males (Chapter 7) and females (Chapter 8) to compare any gender linked differences and the results suggest that females are more sensitive than males to the initial presence of sweat. For both genders, wlocal and ∆GSC are strong predictors of thermal comfort and wetness sensation. More importantly, wlocal can only be used to predict local thermal comfort in conditions of low sweat production or low levels of thermal discomfort. However, once sweat production increases and thermal discomfort worsens ΔGSC (and not wlocal) can predict thermal comfort. Due to low sweat production observed in females indicates that this is only relevant for females. It appears that epidermal hydration has an important role on influencing thermal comfort. Receptors influencing our perceptual responses are located in the epidermis and when sweat is produced and released onto the skin surface, this epidermis swells and the sensitivity of receptors are said to increase. wlocal indicates the amount of moisture present on the skin surface, yet ∆GSC indicates presecretory sweat gland activity and epidermal hydration where the receptors are located. This may explain why on numerous occasions thermal comfort had a stronger relationship with ∆GSC than wlocal. Where Chapter 5 indicated the true local comfort limits for each respective zone, Chapter 7 and 8 provided a global picture of how local regions interact and influence local thermal comfort across the body. When wlocal varies naturally, the torso areas naturally produce more sweat than the extremities and it seemed that these areas produce so much more sweat than the extremities that they dominate local thermal comfort across the whole body. This is referred to in this thesis as a model of segmental interaction. As with thermal comfort, wetness sensation had strong relationships with wlocal and ∆GSC. The results also revealed a strong relationship between wetness sensation and thermal comfort. In contrast to the widely supported claim, a drop in skin temperature is not required to stimulate a wetness sensation. The point at which we detect sweat and when it becomes uncomfortable occurs at different wlocal values across the body. Thermal comfort is shown to be influenced by sweat during exercise in moderate-to-hot conditions. As w has an upper limit the findings suggest that it cannot predict thermal comfort during high sweat rates. Galvanic skin conductance monitors the process of sweat production more closely and thus is a better predictor of thermal comfort during all conditions and particularly during high sweat production. The strong relationship between thermal comfort and wetness sensation confirm the role of sweat production on thermal comfort. Gender differences to perceptual responses were observed, with females generally being more sensitive to sweat and a warm thermal stimulus than males. Regional differences to sweat and a warm stimulus generally suggest that the torso area is more sensitive than the extremities. This is important not only for sports clothing design but also protective clothing at the work place.
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Scucchia, Federica. "Transcriptional profiles inferring thermal stress responses of the coral Oculina patagonica from the Eastern Mediterranean Sea". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/17967/.
Resumen
During the past several decades, corals worldwide have been dealing with a considerable increase in water temperature due to climate change, which is predicted to increase the frequency of coral bleaching and mass mortality events. Nevertheless, corals show differences in stress susceptibility and they are not all affected evenly. The symbiotic coral Oculina patagonica from the Eastern Mediterranean Sea can thrive in relatively unstable environments and is considered a stress-tolerant species. In this study, baseline expression and temporal dynamics of induction of a 70-kDa heat shock protein (HSP70) after an acute heat stress were analyzed in O. patagonica to investigate the influence of its peculiar physiological traits on stress responsiveness. Furthermore, data collected were further discussed within a comparative analysis with similar findings reported in 5 temperate corals of the Mediterranean Sea (Franzellitti et al., 2018). Results show that O. patagonica hsp70 transcriptional response aligns with the formerly observed high resistance for elevated sea water temperatures of this species. The multispecies comparison shows that hsp70 expression varies in accordance with the stress sensitivity of coral populations inhabiting different thermal environments and possessing different trophic strategies and morphologies. This study also reports an analysis of the post heat-stress transcriptional regulation of transcripts related to energy metabolism (gadph), redox regulation (sod), and DNA damage (bcl-2 and bax), disclosing the time line of the events occurring in O. patagonica in response to an acute heat stress, which aligns with its quick recovery from bleaching. These molecular processes analysis is particularly demanding for corals inhabiting the Mediterranean Sea, in light of projected scenarios of anthropogenic global change.
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Rutledge, Charles Jerry 1941. "Physiological Ecology, Population Genetic Responses and Assemblage Stability of Fishes in Two Southwestern Intermittent Stream Systems". Thesis, University of North Texas, 1991. https://digital.library.unt.edu/ark:/67531/metadc277808/.
Resumen
Six sites within the Denton and Hickory Creek watersheds were sampled over three years to assess the impact of seasonal intermittent stream conditions on the ichthyofauna. An integrated approach using field and laboratory techniques was employed to evaluate the responses of the fishes.
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Bennett, Wayne A. (Wayne Arden). "Responses of Selected Texas Fishes to Abiotic Factors, and an Evaluation of the Mechanisms Controlling Thermal Tolerance of the Sheepshead Minnow". Thesis, University of North Texas, 1994. https://digital.library.unt.edu/ark:/67531/metadc277819/.
Resumen
Low oxygen tolerances of ten fishes were estimated using an original nitrogen cascade design, and reciprocally transformed to express responses as ventilated volume necessary to satisfy minimal oxygen demand (L·mg O2^-1). Values ranged from 0.52 to 5.64 L·mg^-1 and were partitioned into three statistically distinct groups. Eight stream fishes showed moderately high tolerances reflecting metabolic adaptations associated with stream intermittency. Juvenile longear sunfish and two mollies comprised the second group. High tolerance of hypoxia may allow juvenile sunfish to avoid predation, and mollies to survive harsh environmental oxygen regimens. The sheepshead minnow was the most tolerant species of low oxygen, of those examined, explaining its presence in severely hypoxic environments.
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Hall, Laun William. "The Evaluation Of Dietary Betaine, Pre And Probiotics, Transitional Substrates, And B-Mercaptoacetate On Physiological, Metabolic, Hormonal And Production Responses In Lactating Holstein Cows Subjected To Thermal Stress". Diss., The University of Arizona, 2014. http://hdl.handle.net/10150/333473.
Resumen
This dissertation evaluated nutritional approaches such as the addition of betaine, prebiotics, probiotics, transitional metabolic substrates, and β-mercaptoacetate (MAA; a compound which inhibits β-oxidation) to the diet of lactating dairy cows to determine their impact on physiological, metabolic, hormonal and production responses during thermal stress. The first objective was to evaluate the use of an organic osmolyte, betaine to reduce the impact of heat stress (HS). Cows were fed either 0 (control; CON), 57 mg/kg BW (mid) or 114 mg/kg (high; HI) body weight (BW) betaine and subjected to thermoneutral (TN) and HS conditions. There was an increase in milk yield during TN with HI betaine over controls (P< 0.01), but the advantage was lost during HS. Plasma glucose increased during HS in HI dose cows compared to control (P < 0.01) as did plasma insulin (P = 0.01). Betaine increased milk production during TN and plasma glucose in HS, but did not improve the HS response. Objective two evaluated the use of a probiotic or direct fed microbial (DFM), Calsporin (Bacillus subtilus C-3102) to decrease the effects of HS in dairy cows. We hypothesized that feeding Calsporin prior to and during HS would reduce pathogenic strains of bacteria, maintain commensal microbes, and improve ruminal anaerobic fermentation resulting in improved milk yield (MY). Milk yield was numerically increased (1.26 kg, P = 0.11) in cows fed Calsporin during TN but was reduced under HS (-2.67 kg, P < 0.01) and milk protein content was decreased (P = 0.05). The DFM tended to decrease somatic cell count (SCC) across periods (P = 0.07). Calsporin addition to the diet did not affect respiration rates and was associated with higher rectal temperature at 1800 in HS (P = 0.02). The expression of heat shock protein 27 (HSP27) was decreased with Calsporin treatment (P = 0.03) and in both HS and TN. The fecal microbial count did not change with the exception of the Calsporin strain in treated animals (P < 0.01). The third objective was to feed OmniGen-AF (OG) to dairy cows before and during thermal stress. We hypothesized that feeding OG to HS dairy cows will improve the immune response, and decrease production losses associated with HS. Cows fed OG maintained lower SCC compared to control (P < 0.01) during the recovery period. We did not detect differences between groups in serum calcium while serum non-esterified fatty acid (NEFA) concentrations (P = 0.10) tended to be greater in OG fed cows across the Agricultural Research Center (ARC) portion including HS. Serum Adrenocorticotropic hormone (ACTH) levels were greater in OG cows (P<0.0001) across all sample days. Feeding OG reduced the HS response including serum Cortisol. The final study measured the effects of the metabolic substrate β-hydroxybutyrate (BHB) during HS on feed intake and metabolites. Under TN conditions the cows received a bolus dose of BHB and dry matter intake (DMI) and metabolites were measured. The second part of this study used a bolus of MAA to limit the up-stream production of acetyl-CoA available for ketogenesis by inhibiting ß-oxidation. We proposed that dosing lactating dairy cows with BHB would decrease DMI, increase plasma insulin, decrease NEFAs and increase skin temperature by vasodilatation. The same cows were then subjected to HS and dosed with saline and MAA on different test days. The infusion of BHB increased skin temperature (time 0.5, 1, 2, 3 and 4°C r² =0.98 with serum BHB) and decreased serum NEFA levels (P < 0.01). There was no change in mean DMI, glucose or insulin. The bolus of MAA decreased feed intake, vaginal temperature, and insulin. There was an increase in serum BHB with the initial dose of MAA and an initial decrease in serum glucose (P < 0.0001) with MAA. Serum glucose increased as insulin decreased with MAA. The infusion of BHB did not alter feed intake in this study despite high plasma levels of BHB.
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Morell, Alaia. "Dynamiques éco-évolutives des espèces exploitées en Mer du Nord en réponse à des variations biotiques et abiotiques de l'environnement". Electronic Thesis or Diss., Université de Lille (2022-....), 2022. http://www.theses.fr/2022ULILR079.
Resumen
Les scénarios de changements globaux sont précieux pour guider les stratégies de gestion et de gouvernance, inciter à la prise de décision et augmenter la prise de conscience collective des tendances futures de la biodiversité. Le degré de réalisme et d'intégration des modèles écosystémiques utilisés à cet effet est en constante progression, mais ils négligent encore souvent l'évolution des populations marines dans les projections futures. Or, celles-ci s'adaptent aux changements globaux, que ce soit par la plasticité phénotypique ou l'évolution, au travers de modifications de leurs caractéristiques biologiques telles que les traits d'histoire de vie, physiologiques et bioénergétiques. L'enjeu de cette thèse est de développer un modèle écosystémique qui permette d'explorer des scénarios de biodiversité aux échelles intra- et inter-spécifiques en représentant explicitement la plasticité phénotypique des traits d'histoire de vie, leur variabilité génétique, leur sélection et leur évolution sous l'influence combinée de la pêche et du changement climatique, ainsi que la dérive génétique et la perte de diversité génétique qui en résultent. Appliqué à la mer du Nord, ce nouveau modèle est utilisé pour comprendre les processus responsables des changements de traits d'histoire de vie qu'ils soient d'origine plastique ou d'origine évolutive. D'une part, les processus bioénergétiques sous-jacents aux changements plastiques sont étudiés par une approche originale comparant les différences entre les courbes de réponses thermiques fondamentales et réalisées pour différentes espèces et stades du cycle de vie. D'autre part, les changements des traits d'histoire de vie sont explorés à travers le prisme de l'évolution grâce à la prise en compte de pressions de sélection multiples telles que la pêche, les interactions proies-prédateurs et le changement climatique.L'intégration des processus plastiques et évolutifs dans les modèles écosystémiques permet de décrire la variabilité interindividuelle des traits biologiques et de comprendre leurs tendances temporelles observées dans le milieu marin. En cela, elle répond à l'enjeu crucial de crédibilité des projections de la biodiversité intra- et inter-spécifique sous scénarios combinant climat et pêche. L'intégration de ces processus permettra également de quantifier plus précisément les effets synergiques et antagonistes de ces deux pressions et de prendre en compte la capacité d'adaptation des populations aux changements globaux pour estimer de manière plus fiable leur résilienceGlobal change scenarios are valuable for guiding management and governance strategies, stimulating decision making, and increasing collective awareness of future biodiversity trends. The degree of realism and integration of ecosystem models used for this purpose is constantly improving, but they still often neglect the evolution of marine populations in future projections. However, marine populations adapt to global changes, either through phenotypic plasticity or evolution, through modifications of their biological characteristics such as life history traits, physiological and bioenergetic traits. The challenge of this thesis is to develop an ecosystem model that allows the exploration of biodiversity scenarios at intra- and inter-specific scales by explicitly representing the phenotypic plasticity of life history traits, their genetic variability, selection and evolution under the combined influence of fisheries and climate change, and the resulting genetic drift and loss of genetic diversity. Applied to the North Sea, this new model is used to understand the processes responsible for changes in life history traits, whether they are of plastic or evolutionary origin. On the one hand, the bioenergetic processes underlying plastic changes are studied by an original approach comparing the differences between the fundamental and realized thermal response curves for different species and life history stages. On the other hand, changes in life history traits are explored through an evolutionary lens by taking into account multiple selection pressures such as fishing, prey-predator interactions and climate change.The integration of plastic and evolutionary processes in ecosystem models allows to describe the inter-individual variability of biological traits and to understand their temporal trends observed in the marine environment. In this way, it responds to the crucial issue of credibility of intra- and inter-specific biodiversity projections under scenarios combining climate and fisheries. The integration of these processes will also allow to quantify more precisely the synergistic and antagonistic effects of these two pressures and to take into account the capacity of populations to adapt to global changes in order to estimate more reliably their resilience
Libros sobre el tema "Thermal physiological responses":
1
Thermal comfort and physiological responses during exercise in a warm-humid environment among young men who wore selected upper body garments. 1989.
2
Thermal comfort and physiological responses during exercise in a warm-humid environment among young men who wore selected upper body garments. 1986.
3
Thermal comfort and physiological responses during exercise in a warm-humid environment among young men who wore selected upper body garments. 1989.
4
Thermal comfort and physiological responses during exercise in a warm-humid environment among young men who wore selected upper body garments. 1989.
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Falk, Bareket y Raffy Dotan. Temperature regulation. Oxford University Press, 2013. http://dx.doi.org/10.1093/med/9780199232482.003.0023.
Resumen
This chapter outlines the physical and physiological changes that occur during growth and maturation and the possible effects these changes can have on the nature and effectiveness of thermoregulation. The physiological responses to heat stress are discussed in terms of metabolic, circulatory, hormonal, and sweating responses, changes in body temperature, and in terms of heat tolerance. Also discussed is hydration status, which can affect thermoregulatory effectiveness in the heat. The physiological response to cold stress is considered in terms of the metabolic and circulatory responses and their possible influence on the effectiveness of thermoregulation. The discussion does not outline the thermoregulatory response per se, but rather emphasizes the differences in that response between children and adults. Finally, child–adult differences in the acclimatization- and training-induced adaptations to thermal stress are discussed.
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Optical-thermal response of laser-irradiated tissue. New York: Plenum Press, 1995.
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Armstrong, Neil y Willem van Mechelen, eds. Oxford Textbook of Children's Sport and Exercise Medicine. Oxford University Press, 2017. http://dx.doi.org/10.1093/med/9780198757672.001.0001.
Resumen
Comprehensive and up to date, this textbook on children’s sport and exercise medicine features research and practical experience of internationally recognized scientists and clinicians that informs and challenges readers. Four sections—Exercise Science, Exercise Medicine, Sport Science, and Sport Medicine—provide a critical, balanced, and thorough examination of each subject, and each chapter provides cross-references, bulleted summaries, and extensive reference lists. Exercise Science covers growth, biological maturation and development, and examines physiological responses to exercise in relation to chronological age, biological maturation, and sex. It analyses kinetic responses at exercise onset, scrutinizes responses to exercise during thermal stress, and evaluates how the sensations arising from exercise are detected and interpreted during youth. Exercise Medicine explores physical activity and fitness and critically reviews their role in young people’s health. It discusses assessment, promotion, and genetics of physical activity, and physical activity in relation to cardiovascular health, bone health, health behaviours, diabetes, asthma, congenital conditions, and physical/mental disability. Sport Science analyses youth sport, identifies challenges facing the young athlete, and discusses the physiological monitoring of the elite young athlete. It explores molecular exercise physiology and the potential role of genetics. It examines the evidence underpinning aerobic, high-intensity, resistance, speed, and agility training programmes, as well as effects of intensive or over-training during growth and maturation. Sport Medicine reviews the epidemiology, prevention, diagnosis, and management of injuries in physical education, contact sports, and non-contact sports. It also covers disordered eating, eating disorders, dietary supplementation, performance-enhancing drugs, and the protection of young athletes.
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Cheung, Stephen S. y Philip N. Ainslie. Advanced Environmental Exercise Physiology. Human Kinetics, 2022. http://dx.doi.org/10.5040/9781718220928.
Resumen
Advanced Environmental Exercise Physiology, Second Edition, offers physiology students and exercise science professionals a complete look at the major topics and debates in the field of environmental physiology. In this second edition, Dr. Stephen Cheung is joined by the coauthor Dr. Phil Ainslie, who has extensive professional expertise in mountaineering and high-altitude physiology and has led numerous high-altitude research expeditions. Among the issues explored in this text are the effects of heat, hydration, and cold in the thermal environment; diving, altitude training, and other pressure effects on the human system; and the influences that pollution and air quality have on exercise. The text also explores the microgravity (space) environment and chronobiological rhythms. The second edition includes new chapters on heat adaptation and therapy, breath-hold diving, physiological adjustments to acute hypoxia, sex differences in environmental response, and cross-adaptation. Through Advanced Environmental Exercise Physiology, Second Edition, readers will learn the following: • The initial physiological responses upon exposure to an environment that a person is not adapted to • How the body adapts to repeated exposure to an environment • How various environments affect the ability to exercise and work • Individual variability in response to stressful environments • Countermeasures that people can take to minimize the impact of environmental stressors Advanced Environmental Exercise Physiology, Second Edition, contains twice the number of figures and illustrations from the previous edition to offer better visualization and explanation of the content. New learning aids include chapter objectives, chapter summaries, and review questions to enhance reader comprehension. Sidebars throughout the text highlight lively areas of current research and debate to stimulate further investigation. Supported by evidence-based information and numerous references, Advanced Environmental Exercise Physiology, Second Edition, addresses the primary environmental factors affecting people when they are working, exercising, and competing in sport. By linking research with recommendations for real-world situations, this text serves as an invaluable resource for students and professionals alike.
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Optical- Response of Laser-Irradiated Tissue (Lasers, Photonics, and Electro-Optics). Springer, 2007.
10
Near, Joseph C. Induction and accumulation of Hsp 70 mRNA in adult salamanders in response to different heat stresses: Including naturally occurring thermal stress conditions in the field. 1989.
Capítulos de libros sobre el tema "Thermal physiological responses":
1
Zlatar, Tomi, J. Oliveira, J. Cardoso, D. Bustos, J. C. Guedes y João S. Baptista. "Influence of Severe Cold Thermal Environment on Thermal Sensation and Physiological Responses". En Studies in Systems, Decision and Control, 363–72. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-14730-3_39.
2
Deaton, A. Shawn, Kyle Watson, Emiel A. DenHartog y Roger L. Barker. "Effectiveness of Using a Thermal Sweating Manikin Coupled with a Thermoregulation Model to Predict Human Physiological Response to Different Firefighter Turnout Suits". En Performance of Protective Clothing and Equipment: Innovative Solutions to Evolving Challenges, 222–36. 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959: ASTM International, 2020. http://dx.doi.org/10.1520/stp162420190077.
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Whiteley, Nia M. y Clara L. Mackenzie. "Physiological responses of marine invertebrates to thermal stress". En Stressors in the Marine Environment, 56–72. Oxford University Press, 2016. http://dx.doi.org/10.1093/acprof:oso/9780198718826.003.0004.
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S. Martin, Lisa, Emma Fraillon, Fabien P. Chevalier y Bérengère Fromy. "Hot on the Trail of Skin Inflammation: Focus on TRPV1/TRPV3 Channels in Psoriasis". En Ion Channels - From Basic Properties to Medical Treatment [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.103792.
Resumen
Transient Receptor Potential Vanilloid (TRPV) channels are expressed in various skin cells, including non-neuronal cell types such as epidermal keratinocytes. They are polymodal sensors of the environment, regulating physiological function in response to a wide variety of stimuli. Indeed, in addition to their significant role in thermal responses and thermoregulation, TRPV channels are also implicated in local skin inflammation processes. Thus, these calcium permeable channels are associated to multiples skin diseases with inflammation, such as atopic dermatitis or psoriasis. In this chapter, we will mainly focus on TRPV1 and TRPV3 channels, as emerging pivotal targets for maintaining skin homeostasis in psoriasis-related inflammation.
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González-Rete, Berenice, Jesús Guillermo Jiménez-Cortés, Margarita Cabrera-Bravo, Paz María Salazar-Schettino, Any Laura Flores-Villegas, José Antonio de Fuentes-Vicente y Alex Córdoba-Aguilar. "Insect vectors of human pathogens in a warming world". En Effects of Climate Change on Insects, 287–302. Oxford University PressOxford, 2024. http://dx.doi.org/10.1093/oso/9780192864161.003.0014.
Resumen
Abstract How do insect vectors (i.e., mosquitoes, blackflies, phlebotomines, tsetse flies, kissing bugs, lice and fleas) and their parasites which affect humanity respond to climate change? This chapter answers this question by reviewing the literature. Researchers have mainly used high temperatures as a proxy of climate change to understand such responses. These responses can be summarized as physiological (heat shock proteins, immunity), ecological (thermal thresholds, reproduction, geographical distribution) and evolutionary (life history, parasite-induced alterations, genetic variation, microbiota). Although many of these responses are species- and parasite-strain specific, it can be concluded that some vectors and parasites show positive adaptive responses to moderate increases in temperature. This represents a serious threat to humanity although more research is needed where fundamental aspects of climate change (e.g., humidity) and the interaction between hosts and vectors are included.
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Maeda, Takafumi, Toshio Kobayashi, Kazuko Tanaka, Akihiko Sato, Shin-Ya Kaneko y Masatoshi Tanaka. "Seasonal differences in physiological and psychological responses to hot and cold environments in the elderly and young males". En Environmental Ergonomics - The Ergonomics of Human Comfort, Health and Performance in the Thermal Environment, 35–41. Elsevier, 2005. http://dx.doi.org/10.1016/s1572-347x(05)80007-2.
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Castillo-Pérez, Ulises, Michael L. May y Alex Córdoba-Aguilar. "Thermoregulation in Odonata". En Dragonflies and Damselflies, 101–12. 2a ed. Oxford University PressOxford, 2022. http://dx.doi.org/10.1093/oso/9780192898623.003.0008.
Resumen
Abstract Odonates are prime subjects to study both the mechanisms of thermoregulation and the ecological and evolutionary responses to global climate change. Odonates use behavioral, color, and physiological strategies (e.g. using their subcuticular tracheal air sacs) to modulate internal temperature. These mechanisms can be used simultaneously and have been mainly studied in anisopteran and zygopteran adults and so there is an open niche for investigating such mechanisms in larvae. Although fairly resilient compared to other insects, adult odonates with dark colors and/or narrow thermal limits face local extinction, based on results from multi- and single species studies. Finally, we invite our readers to foster research on the following topics: a) genetics of thermoregulation; b) thermoregulation mechanisms; c) trade-offs between thermoregulation ability and other traits; and d) using odonates in the field to stimulate cultural awareness about the effects of climate on insects.
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Tokura, Hiromi. "Physiological significance of bright vs. dim light intensities during the daytime for thermoregulatory responses, digestive functions and evening dressing behavior in the cold". En Environmental Ergonomics - The Ergonomics of Human Comfort, Health and Performance in the Thermal Environment, 25–30. Elsevier, 2005. http://dx.doi.org/10.1016/s1572-347x(05)80005-9.
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Holman, J. Alan. "Herpetological Species as Paleoenvironmental Indicators". En Pleistocene Amphibians and Reptiles in Britain and Europe. Oxford University Press, 1998. http://dx.doi.org/10.1093/oso/9780195112320.003.0010.
Resumen
In Chapter 5 we have seen that Pleistocene herpetofaunas are often used to suggest paleoenvironmental conditions. The present chapter discusses the validity of this use. With the exception of behavioral responses (and a few quasi-physiological adaptations in reptiles), herpetological species are poorly adapted to resist temperature changes. Or, to put it another way, amphibians and reptiles lack the complex internal physiological mechanisms that interact to regulate temperature in endotherms. This has led to the assumption by many that herpetological species, because of their supposed greater sensitivity to temperature changes, arc much better indicators of local thermal conditions than are birds and mammals. Moreover, most Quaternary amphibians and reptiles represent extant species whose ecological tolerances and habitat preferences are well known, whereas many Pleistocene endotherms, especially large mammals, are extinct species whose ecological traits and specific habitat requirements are not totally understood. This suggests that Pleistocene herpetofaunas should give more refined information about specific habitats than endothermic faunas. Also, it can be argued that most amphibian and reptile species are more spatially confined than endothermic ones (especially birds and large mammals) and that Pleistocene herpetological species indicate paleoenvironmental conditions of more restricted areas. Bailón and Rage (1992) address this subject in the light of their European experience: "They (amphibians and reptiles] arc unable to compensate for large climatic variations as endotherms (birds and mammals) can; therefore each amphibian and reptile species can live only in a definite climate." (p. 95). Moreover,… Amphibians and reptiles present another advantage: whereas endotherm vertebrates are represented in Quaternary fossiliferous localities by a not negligible percentage of extinct species, practically all fossil amphibians and reptiles of that age belong to extant species. If a species is extinct its ecological requirements cannot be known with certainty and arc open to speculation whereas living species present in fossiliferous assemblages afford accurate information, (p. 95)… They also state that the size of reptile home ranges is small, and that as these species are not the preferred prey of predaccous birds, they are probably not an admixture of species that live in a wide area around the locality. Let us examine these assumptions.
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O’Donnell, Colin F. J. y Jane A. Sedgeley. "Causes and Consequences of Tree-Cavity Roosting in a Temperate Bat, Chalinolobus tuberculatus, from New Zealand". En Functionaland Evolutionary Ecology of Bats, 308–28. Oxford University PressNew York, NY, 2006. http://dx.doi.org/10.1093/oso/9780195154726.003.0017.
Resumen
Abstract Among the 79 taxa of Microchiroptera in Australasia, frequency of treecavity roosting increases as mean annual temperature decreases and latitude increases. This gradient suggests there may be significant thermal benefits to tree-cavity roosting in cold climates. We explore the causes and consequences of tree-cavity roosting during summer months in Chalinolobus tuberculatus, a species that occurs at the southern limit (highest latitude) of this gradient. Five geographically distinct populations are compared. C. tuberculatus selected the oldest and largest trees for maternity roosting and avoided roosting under bark and in caves and buildings, despite the abundance of these sites. It also selected small, well-insulated cavities that accrue significant energy conservation benefits compared with other potential roosts (the ‘‘thermal hypothesis’’). Reproductive females selected roosts that reach maximum temperatures late in the day and retain high temperatures through the night, thus benefiting nonvolant young. Productivity and survival were significantly higher in populations that selected well-insulated roosts. We propose that selection favors smaller, rather than larger, roosting group sizes in this cold, temperate climate. Smaller groups of bats that use relatively small, well-insulated cavities have higher survival rates than larger groups that use larger, less insulated cavities. C. tuberculatus formed behaviorally, though not geographically, isolated subgroups. All colonies exhibited extreme roost-site lability on a daily basis, but strong long-term philopatry among pools exceeding 100 roosts. Most roosts were used once per year but date of reuse was similar each year. Strict temporal philopatry suggests that bats do not switch roosts in response to daily variability in weather conditions. The thermal hypothesis suggests that development of grouping behavior may be an incidental response to physiological constraints on thermoregulation and reproduction. Nevertheless, social interdependence would increase the probability that clusters are large enough on any one day to be thermally beneficial and individuals could improve the reproductive success of other relatives within the group. We conclude by outlining hypotheses that could test the general applicability of findings to tree-cavity roosting bats.
Actas de conferencias sobre el tema "Thermal physiological responses":
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Ji, Lili, Abdelaziz Laouadi, Chang Shu, Abhishek Gaur y Michael Lacasse. "Physiological modeling of thermal responses of the elderly under heat-stressful conditions". En 2021 Building Simulation Conference. KU Leuven, 2021. http://dx.doi.org/10.26868/25222708.2021.31075.
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S. V. Matarazzo, I. J. O. Silva, M. Perissinotto, D. J. Moura y S. A. A Fernandes. "THERMAL CONDITIONED IN RESTING AREA OF FREESTALL FACILITIES AND ITS CONSEQUENCES ON PRODUCTIVE AND PHYSIOLOGICAL RESPONSES IN DAIRY COWS". En 2005 Tampa, FL July 17-20, 2005. St. Joseph, MI: American Society of Agricultural and Biological Engineers, 2005. http://dx.doi.org/10.13031/2013.19474.
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Bähr, Sabina y Fabian Edel. "The effect of colored light in the vehicle interior on the thermal comfort and thermal responses of vehicle occupants". En 14th International Conference on Applied Human Factors and Ergonomics (AHFE 2023). AHFE International, 2023. http://dx.doi.org/10.54941/ahfe1003793.
Resumen
Light and colors have an impact on the mood of car drivers through their emotional change. This result was shown in our last year AHFE-Publication (2022) “Enhanced driver’s experience through emotion sensitive lighting interaction”. The result is that light and color can change the driver’s emotions to the positive and negative. This effect can have lots of further automotive application fields, e. g. the change of the drivers thermal sensation. In case of the e-mobility, warming light and color (red end of the visible spectrum) can support the heating system to get thermal comfort to the driver and will reduce energy for heating and for that increase the electric range. The thermal comfort is very important factor for driving comfort. This work aims to investigate the subjective thermal perception and physiological responses of vehicle occupants through the influence of thermal and visual stimuli in the vehicle interior. To achieve the described goal, a methodological approach was developed. The steps of the methodological approach and the research structure are shown below:•Definition of the research questions; the main question is whether colored light can influence the subjective perception of warmth and the physiology of vehicle occupants through static and dynamic lighting•Obtaining a literature review on the main topics: “thermal comfort”, “lighting in the vehicle interior” and “the influence of colored light on thermal sensation”•Derivation of requirements for the vehicle test setup•Realization of the experimental setup•Conducting a subject study•Evaluation of the data.Study design: A 4 x 2 factorial within subject design is used to determine the influence of “colored light” and “temperature” on thermal, visual, and overall comfort. Of the four scenarios of the predictor variable colored light, three are static and one is dynamic. The static light colors are blue, white, and orange and the dynamic light scenario is a video with candlelight or a video with a winter landscape depending on the temperature level. The two selected temperature levels are 24.5 °C and 26.0 °C. These were regulated via a self-built climate chamber and checked via several sensors. Since the study was conducted in summer, the temperatures were selected to be within (24.5 °C) and outside the comfortable temperature range for the vehicle interior, based on the recommendation of the German automobile association ADAC. Outcome Variables: After experiencing each colored light in combination with temperature, participants answered questions about their thermal, visual, and overall comfort of the vehicle interior environment. To check whether the colored light influences the physiology of participants, heart rate and skin temperature were continuously recorded via a wristband. Sample: Twelve valid subjects (six females, six males) participated in the vehicle lighting study, recruited without financial incentives through the University of Stuttgart and Fraunhofer IAO departments. Procedure: The combination of the predictor variables "colored light" and “temperature” resulted in eight sessions, which were all experienced by the subjects and randomized across the sessions. At the beginning of the study, the subjects received initial instructions and put on the wristband so that the recording of physiological data could start. They then entered the vehicle, and a 13-minute acclimation period began, which served to acclimate the subject to the temperature and to achieve a similar level of activity among the participants. The vehicle was then illuminated with the first color (blue or orange) for 6.5 minutes, and participants were asked to answer questions about the first session after the first four minutes. After that, the light color changed to white for one minute, and then the vehicle was illuminated with the next color. After the first four sessions at the first temperature level, there was a 15-minute break, after which the next four sessions began at the second temperature level. In total, the study lasted approximately 2 hours per participant. Analysis: Is performed using parametric and nonparametric tests. In addition, the covariates age, gender, and BMI of the subject and the temperature difference of the actual to the target temperature were examined for the influence on the outcome variables. The results show that colored light affects thermal perception under different temperature levels. The indoor environment under the orange light was perceived as warmer than under the blue light. In addition, participants found the blue light more comfortable than the orange light in warm environments and they preferred a lower temperature with orange light compared to the blue light or the dynamic video of a winter landscape in warm environments. The use of colored light could therefore lead to energy saving in the e-mobility. The full paper and presentation will go into more detail about the methodology and the results.
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Joshi, Prachi, Hirak Banerjee, Avdhoot V Muli, Aurobinda Routray y Priyadarshi Patniak. "Study of Emotional contagion through Thermal Imaging: A pilot study using noninvasive measures in young adults". En 15th International Conference on Applied Human Factors and Ergonomics (AHFE 2024). AHFE International, 2024. http://dx.doi.org/10.54941/ahfe1004755.
Resumen
Emotional contagion, the process of unconsciously mirroring others’ emotions [6], occurs through various channels including facial expressions, vocal tone, and body language, influencing social interactions and responses to cultural stimuli like music and movies [3], [4], [1]. Facial expressions, analyzed using the Facial Action Coding System (FACS), provide insights into emotional transmission [2]. Thermal imaging, a technique for measuring facial temperature changes, offers a noninvasive method to study emotional responses [5]. However, the facial thermal response to emotional contagion remains understudied. This study aims to investigate how emotional contagion affects facial blood flow among highly emotionally contagious individuals, identified using noninvasive measures. Thermal imaging will capture temperature changes across ten designated facial regions of interest (ROIs), shed-ding light on facial muscle activation. By interpreting temperature variations in these ROIs, researchers seek to understand the physiological processes underlying emotional contagion. Previous studies have shown inconsistent findings regarding facial temperature changes during emotions like fear and joy, highlighting the need for further investigation. This research aims to clarify these discrepancies and advance our understanding of facial thermal responses to emotional contagion, contributing to the broader field of emotion research and potentially informing therapeutic interventions and communication strategies.Initially, Eighteen participants participated in the study. Two groups of standardized emotionally contagious video stimuli (Happy, Fear) were used to induce emotional contagion.The videos started with a one-minute relaxing clip to help participants achieve a neutral emotional state before watching the emotional contagion clips. Following the two-minute emotional contagion video, a blank screen was displayed for one minute to observe the aftereffects of the emotional contagion on participants. Facial temperature was recorded from Fluke Ti 400, and facial expressions were recorded from the webcam. Participants were asked to fill out an emotion-intensity feedback form to rate the experienced emotion and its intensity during video stimuli. Eight participants’ data was removed from further analysis because of inconsistencies. Out of the remaining ten, we further shortlisted five highly emotionally contagious participants with the help of the emotional contagion scale. Ninety baseline and arousal thermal images (10 seconds each) were identified and analyzed using FACS. Ten important regions of interest(ROIs) were selected for facial thermal variations. The interpretation of temperature patterns on selected ROIs produces a physiological time series signal, reflecting changes in blood flow associated with emotional responses. As previously discussed, blood flow radiates across the blood vessels when an emotion happens, which is why a gradual shift in the baseline occurs when an emotion takes place. To assess significant differences in facial thermal temperatures from baseline to emotional contagion, the Mann-Whitney U test and average temperature differences were used. During both emotions (fear and joy), the temperature of the nose decreased on the faces of participants. However, during fear, the temperature dropped in the forehead, left eye corner, and right cheek, while during joy, it increased in the left eye upper region. Additionally, while in fear, the left eye upper, right eye upper, and nose exhibited decreased temperatures, whereas during joy, the forehead, left and right eye corners and nose showed reduced temperatures. Mann Whitney U test showed significant emotional arousal in all the ROIs. Only the right eye corner and left cheek in two participants during fear and the right eye corner during joy in one participant was showing insignificant differences.[1] Amy Coplan. Catching characters emotions: Emotional contagion responses to narrative fiction film. Film Studies, 8(1):26–38, 2006.[2] Paul Ekman. Facial expression and emotion. American psychologist, 48(4):384,1993[3] [3]Carolina Herrando and Efthymios Constantinides. Emotional contagion: a brief overview and future directions. Frontiers in psychology, 12:2881, 2021[4]Giuliana Isabella and Hamilton C. Carvalho.Chapter 4 - emotional contagion and socialization: Reflection on virtual interaction. In Sharon Y. Tettegah and Dorothy L. Espelage, editors, Emotions, Technology, and Behaviors, Emotions and Technology, pages 63–82. Academic Press, San Diego, 2016 [5]Sophie Jarlier, Didier Grandjean, Sylvain Delplanque, Karim N’diaye, Isabelle Cayeux, Maria Ines Velazco, David Sander, Patrik Vuilleumier, and Klaus R. Scherer. Thermal analysis of facial muscles contractions. IEEE Transactions on Affective Computing, 2:2–9, 2011.Eliska Prochazkova and Mariska [6]E. Kret. Connecting minds and sharing emotions through mimicry,Neuroscience Biobehavioral Reviews2017
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Micoulet, Alexandre y Joachim P. Spatz. "Single Cell Mechanics". En ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-43280.
Resumen
In tissues or blood vessels properties and functionalities of cells are influenced substantially by frequent mechanical perturbations. We describe a cantilever-based technique which allows to precisely manipulate a single cell in model experiments in vitro that mimic mechanical situations in vivo. Cell mechanical responses are evaluated under physiological conditions by separating between two basic mechanical perturbations that are constant mechanical stress or constant cell shape deformation. The essential requirements for these investigations are the development of an automated cell force and deformation detection by fiber optics, a feedback loop, and sufficient mechanical stability of the setup under thermal gradients caused by its local heating apart from room temperature to 37°C. Thus, we can discriminate between elastic behavior of a cell, viscoelastic flow at constant strain and active cell responses at both, constant strain or stress. Such quantitative stress-strain data are applied to test physical models that describe cellular responses to mechanical stimuli. Parallel to mechanical characterization, the cell is visualized by optical microscopy which allows concurrent observations of cell shape and intracellular morphological changes.
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Salloum, M., N. Ghaddar y K. Ghali. "A New Transient Bio-Heat Model of the Human Body". En ASME 2005 Summer Heat Transfer Conference collocated with the ASME 2005 Pacific Rim Technical Conference and Exhibition on Integration and Packaging of MEMS, NEMS, and Electronic Systems. ASMEDC, 2005. http://dx.doi.org/10.1115/ht2005-72303.
Resumen
A new mathematical multi-segmented model based on an improved Stolwijk model is developed for predicting nude human thermal and regulatory responses within body segments and the environment. The passive model segments the body into the 15 cylindrical parts. Each body part is divided into four nodes of core, skin, artery blood, and vein blood. The body nodes interact with each other through convection, perfusion and conduction. In any body element, the blood exiting the arteries and flowing into the capillaries is divided into blood flowing in the core (exchanges heat by perfusion in the core) and blood flowing into the skin layer (exchanges heat by perfusion in the skin). The model calculates the blood circulation flow rates based on exact physiological data of Avolio [1], real dimensions, and anatomic positions of the arteries in the body. The circulatory system model takes into consideration the pulsatile blood flow in the macro arteries with its effect on the convective heat transport. The inclusion of calculated blood perfusion in both the tissue and the skin, based on the arterial system model and the heart rate is unique for the current model. The bio-heat human model is capable of predicting accurately nude human transient physiological responses such as the body’s skin, tympanic, and core temperatures, sweat rates, and the dry and latent heat losses from each body segment. The nude body model predictions are compared with published theoretical and experimental data at a variety of ambient conditions and activity. The current model agrees well with experimental data during transient hot exposures. The nude human model has an accuracy of less than 8% for the whole-body heat gains or losses and ±0.48°C for skin temperature values.
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Takano, Masahito, Kosuke Oiwa y Akio Nozawa. "Construction of Facial Skin Temperature-Based Anomaly Detection Model for Daily Fluctuations in Health Conditions". En 9th International Conference on Kansei Engineering and Emotion Research (KEER2022). Kansei Engineering and Emotion Research (KEER), 2022. http://dx.doi.org/10.5821/conference-9788419184849.17.
Resumen
A method for estimating health conditions is required to monitor daily health conditions. Various types of data have been used in healthcare studies; however, imaging data are superior because they allow quick and remote measurements. Thermal face images can be measured safely and economically using infrared thermography. Many physiological and psychological states have been evaluated based on the data from these images. A previous study, using short-term experiments, confirmed that an anomaly detection model constructed using a variational autoencoder enables the detection of anomalous states of thermal face images. A long-term experiment is essential to estimate long-term fluctuating human states, such as health conditions. The purpose of this study is to construct a facial skin temperature-based anomaly detection model for human health conditions. The authors obtained thermal face images with health condition questionnaires for approximately a year. Based on the questionnaire responses, the thermal images in good and poor health conditions were labeled “normal state” and “anomaly state,” respectively. The facial skin temperature-based anomaly detection model for health conditions was constructed using a variational autoencoder with only thermal face images in the normal state. The AUC, which represents anomaly detection performance, was 0.70. In addition, an increasing trend of the performance of the model by learning a wider area of skin temperature was confirmed.
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Liu, Ping, Xiaomin Ren y Lisa X. Xu. "Alternate Cooling and Heating Thermal Physical Treatment: An Effective Strategy Against MDSCs in 4T1 Mouse Mammary Carcinoma". En ASME 2012 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/sbc2012-80229.
Resumen
An alternate thermal physical treatment was developed to destroy tumor tissue using liquid nitrogen cooling and RF heating treatment in our pervious study. Our pervious reports had shown that anti-tumor immunity was induced by the alternate treatment. Myeloid derived suppressor cells (MDSCs) are a subset of heterogeneous, bone marrow derived hematopoietic cells that accumulate in the spleen, bone marrow, blood and tumor sites of tumor-bearing mice and cancer patients. MDSCs are one of the key suppressor cells that regulate anti-tumor immune responses in tumor-bearing hosts. MDSCs have been shown to inhibit the function of various types of cells mediating anti-tumor immunity, such as T cells, B cells, NK cells and dendritic cells. MDSCs are recruited specifically to the tumors and contribute indirectly to angiogenesis, growth and metastasis. MDSCs also exert resistance to cancer therapies, such as anti-VEGF strategies and cancer immunotherapy. Given the role of MDSCs in tumor invasion and metastasis and anti-tumor immune responses, therapeutics targeting MDSCs might offer a new strategy for cancer treatment. In this study, the therapeutic effect and MDSCs changes after the alternate cooling and heating treatment was studied using the 4T1 murine mammary carcinoma, a common animal model of human metastatic breast cancer. Due to its highly invasive and poorly immunogenic characters, the 4T1 tumor could cause death even after the primary tumor was surgically removed. The treatment was carried out when micro-metastases were well established. Comparisons were made with the results from the surgery and hyperthermia groups, respectively. The results showed that MDSCs in blood increased rapidly with time after tumor inoculation, and in 66 days, all the mice died in the control group. The statistical results indicated a significant increase in circulating MDSC numbers at different tumor growth stages. In the surgical resection group, MDSCs in blood did not decrease, but increased rapidly to a level much higher that of the control group in 39 day after tumor inoculation. In the hyperthermia group, MDSCs in blood increased rapidly with time after tumor inoculation, and in 39 day, MDSCs was up to 3 times higher than that of the control group. Mice died in 45 day after initial tumor inoculation. But in the alternate treatment group, the number of MDSCs decreased rapidly and recovered to the normal healthy level in 11 days after the treatment. No metastatic tumor could be observed in these mice, and they were in good physiological conditions as observed in the following 3 month. In conclusion, the alternate treatment was found extremely effective against MDSCs in the very aggressive and highly metastatic mouse mammary carcinoma. The good prognosis was expected in relation to the significant decrease in MDSCs and thus the relief of the immune suppression, induced by the alternate cooling and heating treatment. It could be further developed as a novel therapeutic method against metastatic tumor. On the other hand, combining the alternate treatment with other strategies, such as anti-VEGF and cancer immunotherapy, the best therapeutic effect would be achieved through synergy.
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Itani, Mariam, Nesreen Ghaddar, Kamel Ghali, Beatrice Khater, Djamel Ouahrani y Walid Chakroun. "Experimental Study on Effective Placement of PCM Packets in Cooling Vest to Improve Performance in Warm Environment". En ASME 2017 Heat Transfer Summer Conference. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/ht2017-4756.
Resumen
Global warming has increased the risk of heat stress of outdoor workers and one measure against heat stress is wearing passive personal cooling clothing. Passive body cooling systems, including phase change material (PCM) cooling vests, are considered as an effective solution to improve the working endurance of outdoor active workers. The objective of this study is to assess the effective placement of PCM packets in the cooling vest by examining the local and overall sensation and comfort when: (i) only the frontal segment of the human torso is covered (ii) only the back segment of the human torso is covered and (iii) both segments are covered. The PCM cooling vest is worn by human subjects performing cycling at about 3 Mets and for 30 minutes in a climatic chamber maintained at 28 °C and 60 % relative humidity. The used PCM melting temperature is 28 °C with a coverage area of 642 cm2 and total weight of the vest of 1.19 kg including 8 PCM packets (87.5 grams each). The physiological/thermal responses such as body core and mean skin temperatures, heart rate, and skin wittedness are monitored during the experiments while exercising and wearing the vest. In particular, the frontal and back torso skin temperatures are examined after being subjected to local cooling compared to the case when no PCM packets cover the torso segment. Moreover, subjective votes of thermal comfort, whole body and torso thermal sensations, skin and clothing wetness sensation and perceived exertion are recorded throughout the experiment. The experiment was repeated on five male subjects to ensure robustness of the obtained results. It was found that the core temperature changed slightly when wearing the vest, however the local skin temperature of the back and front torso segments decreased by about 5 °C and 3 °C at the end of the exercise, respectively. Gradual improvement in comfort that reaches a stable level when the PCM starts melting till the end of the exercise was also noticed.
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Song, Donghyun, Eunjee Kim, Yujin Kwon, Woojin Yoon, Baekhee Lee, Yoseob Lee y Gwanseob Shin. "Driver Mental Stress in Response to Thermal Stress Change during Highway Driving". En WCX SAE World Congress Experience. 400 Commonwealth Drive, Warrendale, PA, United States: SAE International, 2023. http://dx.doi.org/10.4271/2023-01-0146.
Resumen
<div class="section abstract"><div class="htmlview paragraph">Monitoring driver thermal stress is an integral step for developing an automated climate control function. In this experimental study, various physiological measures for driver’s thermal stress were tracked while intentionally by altering thermal conditions of the seat with a seat air conditioning system (ACS) in summer and a seat heating system (HS) in winter. It was aimed to determine reliable physiological measures for identifying the changes in thermal status induced by the two seat climate control systems. In the first experiment, twenty experienced drivers drove a comfortable sedan for 60 minutes on a real highway while varying the intensity of the seat ACS every 10 minutes to incur ‘hot’ – ‘cool’ – ‘hot’ – ‘cool’ thermal stress. In the second experiment, a new group of eighteen drivers drove the same highway for 30 minutes while increasing the intensity of seat HS to incur ‘cold’ to ‘warm’ thermal stress. Their thermal stress status has been evaluated by heart rate variability (HRV), skin conductance (SC) level, heart rate (HR), and respiration (RES) rate, as well as subjective discomfort ratings during driving. The reliability of each physiological measure was determined by detection rate, which indicated the ratio of occurrences that the physiological measure followed the changes in thermal conditions. The thermal change by seat ACS was detected over 60% by the high-frequency power of HRV, mean SC level, and RES rate. Changes in the thermal stress by seat HS were detected over 60% by the low-frequency power of HRV and RES rate. The findings of this study suggest that monitoring the driver’s HRV and RES rate may enable the vehicle to detect the changes in the driver’s thermal stress reliably.</div></div>
Informes sobre el tema "Thermal physiological responses":
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Yahav, Shlomo, John McMurtry y Isaac Plavnik. Thermotolerance Acquisition in Broiler Chickens by Temperature Conditioning Early in Life. United States Department of Agriculture, 1998. http://dx.doi.org/10.32747/1998.7580676.bard.
Resumen
The research on thermotolerance acquisition in broiler chickens by temperature conditioning early in life was focused on the following objectives: a. To determine the optimal timing and temperature for inducing the thermotolerance, conditioning processes and to define its duration during the first week of life in the broiler chick. b. To investigate the response of skeletal muscle tissue and the gastrointestinal tract to thermal conditioning. This objective was added during the research, to understand the mechanisms related to compensatory growth. c. To evaluate the effect of early thermo conditioning on thermoregulation (heat production and heat dissipation) during 3 phases: (1) conditioning, (2) compensatory growth, (3) heat challenge. d. To investigate how induction of improved thermotolerance impacts on metabolic fuel and the hormones regulating growth and metabolism. Recent decades have seen significant development in the genetic selection of the meat-type fowl (i.e., broiler chickens); leading to rapid growth and increased feed efficiency, providing the poultry industry with heavy chickens in relatively short growth periods. Such development necessitates parallel increases in the size of visceral systems such as the cardiovascular and the respiratory ones. However, inferior development of such major systems has led to a relatively low capability to balance energy expenditure under extreme conditions. Thus, acute exposure of chickens to extreme conditions (i.e., heat spells) has resulted in major economic losses. Birds are homeotherms, and as such, they are able to maintain their body temperature within a narrow range. To sustain thermal tolerance and avoid the deleterious consequences of thermal stresses, a direct response is elicited: the rapid thermal shock response - thermal conditioning. This technique of temperature conditioning takes advantage of the immaturity of the temperature regulation mechanism in young chicks during their first week of life. Development of this mechanism involves sympathetic neural activity, integration of thermal infom1ation in the hypothalamus, and buildup of the body-to-brain temperature difference, so that the potential for thermotolerance can be incorporated into the developing thermoregulation mechanisms. Thermal conditioning is a unique management tool, which most likely involves hypothalamic them1oregulatory threshold changes that enable chickens, within certain limits, to cope with acute exposure to unexpected hot spells. Short-tem1 exposure to heat stress during the first week of life (37.5+1°C; 70-80% rh; for 24 h at 3 days of age) resulted in growth retardation followed immediately by compensatory growth" which resulted in complete compensation for the loss of weight gain, so that the conditioned chickens achieved higher body weight than that of the controls at 42 days of age. The compensatory growth was partially explained by its dramatic positive effect on the proliferation of muscle satellite cells which are necessary for further muscle hypertrophy. By its significant effect of the morphology and functioning of the gastrointestinal tract during and after using thermal conditioning. The significant effect of thermal conditioning on the chicken thermoregulation was found to be associated with a reduction in heat production and evaporative heat loss, and with an increase in sensible heat loss. It was further accompanied by changes in hormones regulating growth and metabolism These physiological responses may result from possible alterations in PO/AH gene expression patterns (14-3-3e), suggesting a more efficient mechanism to cope with heat stress. Understanding the physiological mechanisms behind thermal conditioning step us forward to elucidate the molecular mechanism behind the PO/AH response, and response of other major organs. The thermal conditioning technique is used now in many countries including Israel, South Korea, Australia, France" Ecuador, China and some places in the USA. The improvement in growth perfom1ance (50-190 g/chicken) and thermotolerance as a result of postnatal thermal conditioning, may initiate a dramatic improvement in the economy of broiler's production.
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Meiri, Noam, Michael D. Denbow y Cynthia J. Denbow. Epigenetic Adaptation: The Regulatory Mechanisms of Hypothalamic Plasticity that Determine Stress-Response Set Point. United States Department of Agriculture, noviembre de 2013. http://dx.doi.org/10.32747/2013.7593396.bard.
Resumen
Our hypothesis was that postnatal stress exposure or sensory input alters brain activity, which induces acetylation and/or methylation on lysine residues of histone 3 and alters methylation levels in the promoter regions of stress-related genes, ultimately resulting in long-lasting changes in the stress-response set point. Therefore, the objectives of the proposal were: 1. To identify the levels of total histone 3 acetylation and different levels of methylation on lysine 9 and/or 14 during both heat and feed stress and challenge. 2. To evaluate the methylation and acetylation levels of histone 3 lysine 9 and/or 14 at the Bdnfpromoter during both heat and feed stress and challenge. 3. To evaluate the levels of the relevant methyltransferases and transmethylases during infliction of stress. 4. To identify the specific localization of the cells which respond to both specific histone modification and the enzyme involved by applying each of the stressors in the hypothalamus. 5. To evaluate the physiological effects of antisense knockdown of Ezh2 on the stress responses. 6. To measure the level of CpG methylation in the promoter region of BDNF in thermal treatments and free-fed, 12-hour fasted, and re-fed chicks during post-natal day 3, which is the critical period for feed-control establishment, and 10 days later to evaluate longterm effects. 7. The phenotypic effect of antisense “knock down” of the transmethylaseDNMT 3a. Background: The growing demand for improvements in poultry production requires an understanding of the mechanisms governing stress responses. Two of the major stressors affecting animal welfare and hence, the poultry industry in both the U.S. and Israel, are feed intake and thermal responses. Recently, it has been shown that the regulation of energy intake and expenditure, including feed intake and thermal regulation, resides in the hypothalamus and develops during a critical post-hatch period. However, little is known about the regulatory steps involved. The hypothesis to be tested in this proposal is that epigenetic changes in the hypothalamus during post-hatch early development determine the stress-response set point for both feed and thermal stressors. The ambitious goals that were set for this proposal were met. It was established that both stressors i.e. feed and thermal stress, can be manipulated during the critical period of development at day 3 to induce resilience to stress later in life. Specifically it was established that unfavorable nutritional conditions during early developmental periods or heat exposure influences subsequent adaptability to those same stressful conditions. Furthermore it was demonstrated that epigenetic marks on the promoter of genes involved in stress memory are altered both during stress, and as a result, later in life. Specifically it was demonstrated that fasting and heat had an effect on methylation and acetylation of histone 3 at various lysine residues in the hypothalamus during exposure to stress on day 3 and during stress challenge on day 10. Furthermore, the enzymes that perform these modifications are altered both during stress conditioning and challenge. Finally, these modifications are both necessary and sufficient, since antisense "knockdown" of these enzymes affects histone modifications, and as a consequence stress resilience. DNA methylation was also demonstrated at the promoters of genes involved in heat stress regulation and long-term resilience. It should be noted that the only goal that we did not meet because of technical reasons was No. 7. In conclusion: The outcome of this research may provide information for the improvement of stress responses in high yield poultry breeds using epigenetic adaptation approaches during critical periods in the course of early development in order to improve animal welfare even under suboptimum environmental conditions.
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Lamont, Susan J., Michael G. Kaiser, Max F. Rothschild, Michael E. Persia, Chris Ashwell y Carl Schmidt. Breed Differences in Physiologic Response to Embryonic Thermal Conditioning and Post-hatch Heat Stress in Chickens. Ames (Iowa): Iowa State University, enero de 2015. http://dx.doi.org/10.31274/ans_air-180814-1316.
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Yahav, Shlomo, John Brake y Noam Meiri. Development of Strategic Pre-Natal Cycling Thermal Treatments to Improve Livability and Productivity of Heavy Broilers. United States Department of Agriculture, diciembre de 2013. http://dx.doi.org/10.32747/2013.7593395.bard.
Resumen
The necessity to improve broiler thermotolerance and live performance led to the following hypothesis: Appropriate comprehensive incubation treatments that include significant temperature management changes will promote angiogenesis and will improve acquisition of thermotolerance and carcass quality of heavy broilers through epigenetic adaptation. It was based on the following questions: 1. Can TM during embryogenesis of broilers induce a longer-lasting thermoregulatory memory (up to marketing age of 10 wk) that will improve acquisition of thermotolerance as well as increased breast meat yield in heavy broilers? 2. The improved sensible heat loss (SHL) suggests an improved peripheral vasodilation process. Does elevated temperature during incubation affect vasculogenesis and angiogenesis processes in the chick embryo? Will such create subsequent advantages for heavy broilers coping with adverse hot conditions? 3. What are the changes that occur in the PO/AH that induce the changes in the threshold response for heat production/heat loss based on the concept of epigenetic temperature adaptation? The original objectives of this study were as follow: a. to assess the improvement of thermotolerance efficiency and carcass quality of heavy broilers (~4 kg); b. toimproveperipheral vascularization and angiogenesis that improve sensible heat loss (SHL); c. to study the changes in the PO/AH thermoregulatory response for heat production/losscaused by modulating incubation temperature. To reach the goals: a. the effect of TM on performance and thermotolerance of broilers reared to 10 wk of age was studied. b. the effect of preincubation heating with an elevated temperature during the 1ˢᵗ 3 to 5 d of incubation in the presence of modified fresh air flow coupled with changes in turning frequency was elucidated; c.the effect of elevated temperature on vasculogenesis and angiogenesis was determined using in ovo and whole embryo chick culture as well as HIF-1α VEGF-α2 VEGF-R, FGF-2, and Gelatinase A (MMP2) gene expression. The effects on peripheral blood system of post-hatch chicks was determined with an infrared thermal imaging technique; c. the expression of BDNF was determined during the development of the thermal control set-point in the preoptic anterior hypothalamus (PO/AH). Background to the topic: Rapid growth rate has presented broiler chickens with seriousdifficulties when called upon to efficiently thermoregulate in hot environmental conditions. Being homeotherms, birds are able to maintain their body temperature (Tb) within a narrow range. An increase in Tb above the regulated range, as a result of exposure to environmental conditions and/or excessive metabolic heat production that often characterize broiler chickens, may lead to a potentially lethal cascade of irreversible thermoregulatory events. Exposure to temperature fluctuations during the perinatal period has been shown to lead to epigenetic temperature adaptation. The mechanism for this adaptation was based on the assumption that environmental factors, especially ambient temperature, have a strong influence on the determination of the “set-point” for physiological control systems during “critical developmental phases.” Recently, Piestunet al. (2008) demonstrated for the first time that TM (an elevated incubation temperature of 39.5°C for 12 h/d from E7 to E16) during the development/maturation of the hypothalamic-hypophyseal-thyroid axis (thermoregulation) and the hypothalamic-hypophyseal-adrenal axis (stress) significantly improved the thermotolerance and performance of broilers at 35 d of age. These phenomena raised two questions that were addressed in this project: 1. was it possible to detect changes leading to the determination of the “set point”; 2. Did TM have a similar long lasting effect (up to 70 d of age)? 3. Did other TM combinations (pre-heating and heating during the 1ˢᵗ 3 to 5 d of incubation) coupled with changes in turning frequency have any performance effect? The improved thermotolerance resulted mainly from an efficient capacity to reduce heat production and the level of stress that coincided with an increase in SHL (Piestunet al., 2008; 2009). The increase in SHL (Piestunet al., 2009) suggested an additional positive effect of TM on vasculogenesis and angiogensis. 4. In order to sustain or even improve broiler performance, TM during the period of the chorioallantoic membrane development was thought to increase vasculogenesis and angiogenesis providing better vasodilatation and by that SHL post-hatch.
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Yahav, Shlomo, John Brake y Orna Halevy. Pre-natal Epigenetic Adaptation to Improve Thermotolerance Acquisition and Performance of Fast-growing Meat-type Chickens. United States Department of Agriculture, septiembre de 2009. http://dx.doi.org/10.32747/2009.7592120.bard.
Resumen
: The necessity to improve broiler thermotolerance and performance led to the following hypothesis: (a) thethermoregulatory-response threshold for heat production can be altered by thermal manipulation (TM) during incubation so as to improve the acquisition of thermotolerance in the post-hatch broiler;and (b) TM during embryogenesis will improve myoblast proliferation during the embryonic and post-hatch periods with subsequent enhanced muscle growth and meat production. The original objectives of this study were as follow: 1. to assess the timing, temperature, duration, and turning frequency required for optimal TM during embryogenesis; 2. to evaluate the effect of TM during embryogenesis on thermoregulation (heat production and heat dissipation) during four phases: (1) embryogenesis, (2) at hatch, (3) during growth, and (4) during heat challenge near marketing age; 3. to investigate the stimulatory effect of thermotolerance on hormones that regulate thermogenesis and stress (T₄, T₃, corticosterone, glucagon); 4. to determine the effect of TM on performance (BW gain, feed intake, feed efficiency, carcass yield, breast muscle yield) of broiler chickens; and 5. to study the effect of TM during embryogenesis on skeletal muscle growth, including myoblast proliferation and fiber development, in the embryo and post-hatch chicks.This study has achieved all the original objectives. Only the plasma glucagon concentration (objective 3) was not measured as a result of technical obstacles. Background to the topic: Rapid growth rate has presented broiler chickens with seriousdifficulties when called upon to efficiently thermoregulate in hot environmental conditions. Being homeotherms, birds are able to maintain their body temperature (Tb) within a narrow range. An increase in Tb above the regulated range, as a result of exposure to environmental conditions and/or excessive metabolic heat production that often characterize broiler chickens, may lead to a potentially lethal cascade of irreversible thermoregulatory events. Exposure to temperature fluctuations during the perinatal period has been shown to lead to epigenetic temperature adaptation. The mechanism for this adaptation was based on the assumption that environmental factors, especially ambient temperature, have a strong influence on the determination of the “set-point” for physiological control systems during “critical developmental phases.” In order to sustain or even improve broiler performance, TM during the period of embryogenesis when satellite cell population normally expand should increase absolute pectoralis muscle weight in broilers post-hatch. Major conclusions: Intermittent TM (39.5°C for 12 h/day) during embryogenesis when the thyroid and adrenal axis was developing and maturing (E7 to E16 inclusive) had a long lasting thermoregulatory effect that improved thermotolerance of broiler chickens exposed to acute thermal stress at market age by lowering their functional Tb set point, thus lowering metabolic rate at hatch, improving sensible heat loss, and significantly decreasing the level of stress. Increased machine ventilation rate was required during TM so as to supply the oxygen required for the periods of increased embryonic development. Enhancing embryonic development was found to be accomplished by a combination of pre-incubation heating of embryos for 12 h at 30°C, followed by increasing incubation temperature to 38°C during the first 3 days of incubation. It was further facilitated by increasing turning frequency of the eggs to 48 or 96 times daily. TM during critical phases of muscle development in the late-term chick embryo (E16 to E18) for 3 or 6 hours (39.5°C) had an immediate stimulatory effect on myoblast proliferation that lasted for up to two weeks post-hatch; this was followed by increased hypertrophy at later ages. The various incubation temperatures and TM durations focused on the fine-tuning of muscle development and growth processes during late-term embryogenesis as well as in post-hatch chickens.