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Understanding the brain response to thermal stimuli is crucial in the sensory experience. This study focuses on non-painful thermal stimuli, which are sensations induced by temperature changes without causing discomfort. These stimuli are transmitted to the central nervous system through specific nerve fibers and are processed in various regions of the brain, including the insular cortex, the prefrontal cortex, and anterior cingulate cortex. Despite the prevalence of studies on painful stimuli, non-painful thermal stimuli have been less explored. This research aims to bridge this gap by investigating brain functional connectivity during the perception of non-painful warm and cold stimuli using electroencephalography (EEG) and the partial directed coherence technique (PDC). Our results demonstrate a clear contrast in the direction of information flow between warm and cold stimuli, particularly in the theta and alpha frequency bands, mainly in frontal and temporal regions. The use of PDC highlights the complexity of brain connectivity during these stimuli and reinforces the existence of different pathways in the brain to process different types of non-painful warm and cold stimuli.

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Little has been studied about microclimate and the thermal comfort during the implementation of silvopastoral systems. This study aimed to evaluate the microclimate and thermal comfort during the implementation of High Biodiversity Silvopastoral System with Nuclei (SPSnu). Three treatments were investigated, SPSnu with 5 and 10% of the pasture area with nuclei, (SPSnu5 and SPSnu10, respectively), and treeless pasture (TLP). Each treatment was subdivided into 4 areas: within the nuclei, around the nuclei, around the nuclei with shade and internuclei. The analyzed variables were soil surface temperature, air temperature, wind speed, relative humidity, black globe temperature and the Heat Load Index (HLI) at 20 and 120 cm height. We hypothesized that the wind speed reduction associated with insufficient shade projection typical of the first years of SPSs may interfere in microclimate and thermal comfort during the hot seasons. SPSnu5 and SPSnu10 had a reduction in wind speed of 51.58% and 68.47% respectively when compared to TLP at 20 cm. Soil surface temperature and air temperature at 120 cm were higher for SPSnu than TLP. The same effect was observed for the HLI. At 20 cm, HLI indicated better thermal comfort in TLP than in the SPSnu treatments. The lack of shade projection from young nuclei in conjunction with the decrease of wind speed between the nuclei caused a higher air temperature and HLI in the SPSnu treatments, we called this conditions, windbreak countereffect. Farmers must knowledge this effect when implementing SPSs, and when necessary, mitigate with the proper management decisions.

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This study aims to evaluate agreement among subjective thermal comfort, thermal sensation, thermal perception, and thermal tolerance indices, according to pedestrians in downtown Santa Maria, southern Brazil, which has a humid subtropical climate (Cfa). Between August 2015 and July 2016 (three periods), 1728 questionnaires were applied. Evaluation of the dependence of statistical variables was based on gender and age, at three periods of time: August 2015 (864 respondents), January 2016 (432 respondents), and July 2016 (432 respondents). Statistical evaluation was based on Pearson's chi-square test using RStudio software, and a significance level (α) of 5% for thermal comfort, thermal sensation, thermal preference, and thermal tolerance was used. Results indicated that age and gender affect the relationship between the variables. Thermal comfort and thermal tolerance presented the best correlation and coherence, regardless of age or gender. This study contributes to knowledge on the local microclimate and can contribute to urban planning to implement strategies that improve pedestrians' thermal comfort.

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Here, we evaluated the influence of outdoor environmental conditions (synoptic weather conditions) on human thermal discomfort in the five macro-regions of Pelotas city, located in the southernmost region of Brazil. To do this, meteorological sensors (HOBO MX2301A) were installed outside the residences to measure the air temperature, dew point temperature, and relative humidity between 18 January and 20 August 2019. Two well-established simplified biometeorological indices were examined seasonally: (i) humidex for the summer months and (ii) effective temperature as a function of wind for the autumn and winter months. Our findings showed seasonal differences related to human thermal discomfort and outdoor environmental conditions. The thermal discomfort was highest in the afternoons during the summer months and at night during the winter months. The seasonal variation in human thermal discomfort was highly associated with the meteorological conditions. In summer, the presence of the South Atlantic Subtropical Anticyclone (SASA) contributed to heat stress. The SASA combined with the continent's low humidity contributed to the perceived sensation of thermal discomfort. In the winter, thermal discomfort was associated with the decrease in air humidity caused by high atmospheric pressure systems, which led to a decrease in both air temperature and air moisture content. Our findings suggest that a better understanding of the complex interplay between outdoor environmental factors and human thermal comfort is needed in order to mitigate the negative effects of thermal discomfort.

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A popular belief states that if frog is submerged in a container and gradually heats it up, it will try to adapt until it dies; this is probably the situation faced by more and more human populations. As stated by thousands of scientists, academics, and researchers worldwide, the planet's warming is directly related to climate change.

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Courtyards have been used over many centuries as an interesting architectural feature that extends the living area, with good opportunities for relaxation, contemplation, and also for social interactions in such interface with the outdoor environment. Those areas can also act as climate modifiers and have tempering effects in hot regions. Depending on their geometrical features, courtyards can promote excellent shading and natural ventilation opportunities in tropical regions. This study is focused on the evaluation of two historic courtyards with very distinct solar exposure in a city located in a tropical savannah climate. Field monitoring was carried out alongside surveys with visitors to the courtyards. Results showed the potential of both courtyards in reducing the level of heat stress during peak daytime hours with their climate tempering function. The deeper courtyard yielded steadier cooling effect during daytime than the shallower one. Heat stress, here interpreted in terms of the universal thermal climate index (UTCI) was also more reduced in the deep courtyard. For the subjective part, there was a larger fluctuation of thermal sensation votes for a low level of heat stress in the shallower courtyard but less so and even an opposite pattern for higher heat stress. In essence, the geometric shape of the evaluated courtyards was considered to be paramount to provide thermal attenuation to their visitors due to the interplay between shading and solar access, even though the effect was not observed in their TS votes for increasing heat stress.

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Fiber-optic distributed temperature sensing (DTS) has been widely used since the end of the 20th century, with various industrial, Earth sciences, and research applications. To obtain precise thermal measurements, it is important to extend the currently available DTS calibration methods, considering that environmental and deployment factors can strongly impact these measurements. In this work, a laboratory experiment was performed to assess a currently available duplexed single-ended DTS calibration algorithm and to extend it in case no temperature information is available at the end of the cables, which is extremely important in geothermal applications. The extended calibration algorithms were tested in different boreholes located in the Atacama Desert and in the Central Andes Mountains to estimate the geothermal gradient in these regions. The best algorithm found achieved a root mean square error of 0.31 ± 0.07 °C at the far end of a ~1.1-km cable, which is much smaller than that obtained using the manufacturer algorithm (2.17 ± 0.35 °C). Moreover, temperature differences between single- and double-ended measurements were less than 0.3 °C at the far end of the cable, which results in differences of ~0.5 °C km-1 when determining the geothermal gradient. This improvement in the geothermal gradient is relevant, as it can reduce the drilling depth by at least 700 m in the study area. Future work should investigate new extensions of the algorithms for other DTS configurations and determining the flow rate of the Central Andes Mountains artesian well using the geothermal profile provided by the DTS measurements and the available data of the borehole.

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With the aging of the human body, some physiological changes occur, compromising thermoregulatory mechanisms, negatively influencing the individual's thermal sensation. Given this fact, the present study aimed to build a predictive model to determine the thermal sensation index for elderly people (TSIEP) in a hot climate region, considering their sensitivity in the perception of climate change in the city of Campina Grande, in the semi-arid region of Paraíba/Brazil. For this purpose, an observational study was carried out from April to December 2016 with elderly people inside their homes. The responses of the sample units (elderly people) to the categories of thermal sensation (hot, comfortable, and cold) were transformed into probit estimates, and, using the multivariate modeling statistical technique (canonical correlation), the TSIEP was determined. Finally, TSIEP showed that the thermal sensation of elderly people residing in Campina Grande tends to be more sensitive to cold and less sensitive to heat.

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With the expanding use of thermal assessment techniques in beef cattle, infrared thermography has become a promising tool for assessing the environment for animal thermal comfort. Goals of this study were: (1) to evaluate cattle thermal comfort in agroforestry systems with different shade availability (2) to verify the spatiotemporal variations of infrared temperature inside agroforestry systems, and; (3) to test infrared thermography as a potential tool to assess animal thermal comfort indices in agroforestry systems. A trial was carried out between June 2015 and February 2016, covering Central-Brazil's dry winter and rainy summer seasons, respectively. The experimental area of Embrapa Beef Cattle is located in Campo Grande (Mato Grosso do Sul), coordinates 20°24'53″ S, 54°42'26″ W and 558 m altitude. The 12 ha plot has two agroforestry systems varying shade availability. Traditional Black Globe Temperature and Humidity Index, Heat Load Index and Radiation Thermal Load were determined, from measurements using digital thermo-hygrometers, with datalogger. Surface temperature and humidity of tree canopies and pasture were determined using an infrared thermographic camera. Results show spatiotemporal variations in infrared temperature. This means that the environment inside agroforestry systems is not homogeneously comfortable for cattle, and the system with the lowest shade availability has the greatest heat accumulation area. Weak to strong associations were identified between infrared variables and thermal comfort indices (0.08 = r ≤ 0.75). Positive relationships were also obtained and equally well explained by the Black Globe Temperature and Humidity Index and Heat Load Index (0.55 = R2 ≤ 0.94). We conclude that infrared thermography can be used as a tool to assess thermal comfort indices in agroforestry systems and to determine onset of animal thermal stress from environment and heat body accumulation.

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This work is taken up to evaluate the relationship between the thermal comfort of spectators and athletes and the prevailing meteorological conditions during Rio 2016 Olympic Games. Empirical and physiological thermal comfort indices are calculated from data collected from an automatic weather station installed near the Olympic Stadium and interviews with the spectators. The study period was marked by a gradual rise in air temperature and by the occurrence of two significant weather events associated with wind gusts, which caused disturbances in some areas of the competitions. ET and NET were below the air temperature, indicating that both humidity and wind contributed to the reduction of the human-biometeorological indices. Majority of the interviewed persons reported comfortable sensation and weather conditions. These perceptions corroborate results of the thermal comfort indices calculated for these resting spectators. The comfort indices calculated for the athletes with high level of physical activity showed that PET estimated hotter thermal sensation those for the individuals at rest, indicating that the physical type of a person may strongly influence the thermal sensation and comfort during intense physical activity. Increasing trend observed in all the indices of human thermal comfort during the period of study shows consistency among them.

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Brazil is the country with the highest social inequality in South America. This socioeconomic disparity reflects not only on the families' income but also on their spatial localization in the city, as well as on the urban design. These urban environments can alter the urban microclimate, and consequently, interfere in dwellers' thermal comfort. This research investigated the relationship between socio-spatial inequalities and thermal comfort in two different Local Climate Zones (LCZ) using a combination of measurement and modeling. Air temperature (Tair) was obtained by on-site measurements in compact high-rise (LCZ1) and compact low-rise buildings (LCZ3) and Mean radiant temperature (Tmrt) was simulated using SOlar and LongWave Environmental Irradiance Geometry (SOLWEIG). The results indicated that in LCZ1 seafront-localized buildings, in which residents have a higher income, the temperature remains in a range classified as comfortable, mainly due to shading and sea breeze. On the other hand, LCZ3, located in the periphery of the city, in which the low-income population is concentrated and is marked by a precariousness urban environment, presented a higher air temperature and Tmrt values, exposing the dwellers to heat stress throughout the year, especially during the summer season. These observations suggested that public and private actions tend to promote better urban designs in areas with a higher concentration of income. Public reforms aimed at improving the urban environment and promoting thermal comfort should be a priority for the warmest LCZ, where the poorest residents live. Public agents should rethink the distribution of environmental resources to promote equitable urban spaces.

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Both global climate change and urbanization trends will demand adaptation measures in cities. Large agglomerations and impacts on landscape and natural environments due to city growth will require guided densification schemes in urban areas, particularly in developing countries. Human biometeorological indices such as the Universal Thermal Climate Index (UTCI) could guide this process, as they provide a clear account of expected effects on thermal sensation from a given change in outdoor settings. However, an earlier step should optimally include an adequacy test of suggested comfort and thermal stress ranges with calibration procedures based on surveys with the target population. This paper compares obtained thermal comfort ranges for three different locations in Brazil: Belo Horizonte, 20° S, Aw climate type; Curitiba, 25.5° S, Cfb subtropical climate, both locations in elevation (above 900 m a.s.l.); and Pelotas, at sea level, latitude 32° S, with a Cfa climate type. In each city, a set of outdoor comfort field campaigns has been carried out according to similar procedures, covering a wide range of climatic conditions over different seasons of the year. Obtained results indicate a variation of neutral temperatures up to 3 °C (UTCI units) as a possible latitude and local climate effect between the southern locations relative to the northernmost location. Low UTCI values were found in the two subtropical locations for the lower threshold of the thermal comfort band as compared with the original threshold. A possible explanation for that is a longer exposure to cold conditions as buildings are seldom provided with heating systems.

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TRPM8 is the main molecular entity responsible for cold sensing. This polymodal ion channel is activated by cold, cooling compounds such as menthol, voltage, and rises in osmolality. In corneal cold thermoreceptor neurons (CTNs), TRPM8 expression determines not only their sensitivity to cold, but also their role as neural detectors of ocular surface wetness. Several reports suggest that Protein Kinase C (PKC) activation impacts on TRPM8 function; however, the molecular bases of this functional modulation are still poorly understood. We explored PKC-dependent regulation of TRPM8 using Phorbol 12-Myristate 13-Acetate to activate this kinase. Consistently, recombinant TRPM8 channels, cultured trigeminal neurons, and free nerve endings of corneal CTNs revealed a robust reduction of TRPM8-dependent responses under PKC activation. In corneal CTNs, PKC activation decreased ongoing activity, a key parameter in the role of TRPM8-expressing neurons as humidity detectors, and also the maximal cold-evoked response, which were validated by mathematical modeling. Biophysical analysis indicated that PKC-dependent downregulation of TRPM8 is mainly due to a decreased maximal conductance value, and complementary noise analysis revealed a reduced number of functional channels at the cell surface, providing important clues to understanding the molecular mechanisms of how PKC activity modulates TRPM8 channels in CTNs.

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This paper discusses the influence of the user thermal comfort conditions on the time spent in open spaces through a case study performed in Bauru, Sao Paulo, Brazil. The study was carried out in two subspaces of a zoo, under warm and wet conditions. Although the subspaces had different levels of shading, they were of similar interest to visitors. The methodology adopted the collection of objective (air and globe temperature, humidity, and velocity) and subjective data (by application of questionnaires), for a sample of 174 users, and local observations with photographic records each 3 min. Data and images obtained enabled the characterization of the local microclimates and contributed to evaluate (1) user's thermal perception (7-point scale), (2) affective evaluation of the thermal comfort (4-point scale), (3) thermal preference (7-point scale), (4) calculated thermal perception (through PET (physiological equivalent temperature) index), and (5) user's exposure time in each subspace. The great contributions of this work were to identify that in the subspace with bigger shading and less rigorous microclimatic conditions, users had exposure time longer than another more exposed to solar radiation and to validate a method to measure user's exposition time through sequential photos. These results contribute to a discussion that has yet been little explored in the literature of the area, proving the strong influence of the thermal comfort conditions in the users' exposure time in open spaces.

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The present study carried out assessments regarding thermal sensations under different weather conditions in three urban areas in Cuiabá, Brazil, a Tropical Savannah climate (Aw) region. Thermal acceptability by means of thermal sensation votes (TSV) was addressed based on the estimation of the Universal Thermal Climate Index (UTCI) values. Important issues related to clothing thermal insulation (Icl), the effect of gender on thermal sensation, and implications of artificial conditioning (AC) systems are also evaluated. Micrometeorological variables were determined and 685 questionnaires were applied to evaluate individual pedestrian thermal preferences. The Icl observed in the Tropical climate was lower than that intrinsically inputted by the UTCI for Temperate climates. The local thermal comfort zone ranged between 21.5 and 28.5 °C, with both thresholds higher than those observed in studies conducted in Subtropical, Mediterranean, and Continental Temperate climates while the local hot thermal sensation categories were displaced at least 3 °C above than those for the aforementioned climates. The effect of gender on thermal sensation indicated that females are more sensitive to cold stress conditions than males, requiring higher Icl for temperatures below 28 °C. The physiological adaptation by continuous exposure to AC systems reduced the neutral temperature between AC and non-artificial conditioning system users (NAC) by 0.8 °C, with more intense differences in hot TSV ranges. This study reveals differences between stated TSV classes derived for other climates and those resulting from TSV declared by Savannah local residents, indicating that local thermal sensation scale for UTCI in an important key for environment planning.

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Abstract Aims: Recently, high-intensity training methods have become popular, integrating the cardiovascular and neuromuscular training in a single training session, among these methods is CrossFit®. The objective of this study was to analyze the superficial thermal response to CrossFit® exercise in men and women, in order to use this knowledge to prevent overuse injuries. Methods: Nineteen volunteers involved in CrossFit® exercise for more than 6-month (12 males and 7 females) were recruited. The acquisition of the thermal images was performed in a climatized room in two moments, at rest (before exercise), and after one CrossFit® training session. The training session lasted 45min, comprising warm-up (10-min), accessory work (15-20min), and workout of the day (15-20-min). Before the first image acquisition, volunteers were acclimated for 15 min. The Wilcoxon signed-rank test was used to compare the skin temperature between pre- and post-exercise. Results: Temperatures rose significantly pre- to post-exercise in the forearm and anterior thigh regions, while it decreased in the anterior thorax and dorsal lower back regions. These results were found both, in the overall sample, and the male volunteers, but not when the female results were isolated. Conclusion: It can be concluded that superficial thermal response to one CrossFit® training session was characterized and was different for men and women. The superficial thermal responses were aligned with the physiological alterations promoted by other modalities, such as resistance training, cycling, and running.

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The objective was to evaluate vaginal temperature as a thermoregulatory response of Nellore heifers under different microclimatic conditions. The study was conducted during one year in an experimental area located at 54°37'W, 20°27'S, and 530 m of altitude in Brazil. Twenty-four Nellore females were reared in integrated crop-livestock-forestry systems with different shading patterns. The randomized complete block experimental design was utilized with a sub subdivided plots scheme, with plot corresponding to the production systems, the subplot to the season of the year, and the sub subplot, the hours of the day. To characterize the microclimate, data regarding air and black globe temperatures, and air relative humidity were collected and from them, temperature-humidity index was calculated. Vaginal temperature was obtained by using a bottom-type temperature logger (i-button) attached to an adapted intravaginal device. The black-globe temperature explained the variation on vaginal temperature. Increases on vaginal temperature were only observed, on average, two hours after the increase of black-globe temperature. The microclimatic conditions found in the systems, resulting from the various tree densities, modify the vaginal temperature in different degrees, demonstrating that the shading effect is not always accompanied by improvements in thermal comfort. The system with intermediate density showed a better microclimatic condition and, consequently, a lower increase in vaginal temperature. The interaction between air temperature, humidity and solar radiation resulted in adverse environmental conditions, however, Nellore heifers showed good adaptation to the environment. In conclusion, vaginal temperature is a good indicator to evaluate the thermoregulatory response in Nellore heifers.

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In tropical environments, stingless bees are an important group of pollinators, helping to maintain plant biodiversity and, consequently, to preserve ecosystems. The foraging activity of these insects is influenced by biotic and abiotic factors. Although air temperature limits activities outside the hive, the natural thermal environment is complex; meteorological variables interact with each other, requiring elaborate thermoregulatory responses from bees. The complexity of the thermal environment has been the subject of recent research on insect thermoregulation. The effects of wind and especially solar radiation should be considered when studying the behavior of stingless bees. In this context, this mini-review aimed to address the main components of the thermal environment that influence the foraging activity of stingless bees.

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In tropical environments, stingless bees are an important group of pollinators, helping to maintain plant biodiversity and, consequently, to preserve ecosystems. The foraging activity of these insects is influenced by biotic and abiotic factors. Although air temperature limits activities outside the hive, the natural thermal environment is complex; meteorological variables interact with each other, requiring elaborate thermoregulatory responses from bees. The complexity of the thermal environment has been the subject of recent research on insect thermoregulation. The effects of wind and especially solar radiation should be considered when studying the behavior of stingless bees. In this context, this mini-review aimed to address the main components of the thermal environment that influence the foraging activity of stingless bees.(AU)

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