Hot Humid Conditions Research Articles

Pre-exercise ingestion of a low glycaemic index rice-based mixed meal increases fat oxidation and endurance running performance in a hot-humid environment.

Relative to exercise in a thermoneutral environment, there is only limited evidence demonstrating that a low glycaemic index (LGI) pre-exercise meal can enhance endurance exercise performance in a hot-humid (HH) condition. Also, previous studies predominantly utilised Western-based and single food items, with minimal focus on Asian-based mixed meals. This study aimed to investigate the impact of pre-exercise LGI and high glycaemic index (HGI) rice-based mixed meals on endurance performance among acclimatised trained athletes in HH condition (32°C, 65% relative humidity). Twelve native-born endurance-trained male runners (age 22.0 ± 5.8 years; peak oxygen consumption (V̇O2peak) 64.2 ± 5.5 mL.kg-1.min-1) completed two trials consisting of 45-min steady-state (SS) run at 70% V̇O2peak followed by 10 km performance run (TT10km). Three hours before exercise, participants consumed an isocaloric rice-based mixed meals containing either LGI (GI=47) or HGI (GI=80), providing 1.3 g of carbohydrate (CHO) per kg of body mass. Participants ran faster during TT10km after consuming the LGI meal compared to the HGI meal (LGI: 55.18 ± 1.22 vs. HGI: 57.03 ± 2.25 min, p = 0.010). End rectal temperature did not significantly differ between trials (LGI: 39.16 ± 0.74 vs. HGI: 38.95 ± 0.46°C, p = 0.352). Fat oxidation was higher during the SS run in the LGI compared to the HGI trial (LGI: 0.19 ± 0.05 vs. HGI: 0.13 ± 0.19 g.min-1, p = 0.001). This study demonstrated that, relative to HGI, consuming a pre-exercise LGI rice-based mixed meal enhanced endurance performance in HH environment among acclimatised trained male athletes.

A modified multi-node human thermoregulation model with improved sweating response to simulate human physiological behaviours in warm and hot environments

The present research developed a modified multi-node thermoregulation model derived from the renowned Tanabe and JOS series models (JOS-2 and JOS-3). The JOS-3 model's predictions showed an abrupt spike in mean skin temperature, contradicting the findings from experiments. The JOS-3 model's sweating mechanism exhibits an inconsistency, and the sweating mechanism is not triggered promptly and accurately, leading to a sudden rise in skin temperature. This disparity significantly impacts the ability of the model to precisely replicate thermoregulatory responses under various climatic conditions and levels of physical activity. The proposed modified thermoregulation model extends the JOS-3 model by modifying the set-point temperature and sweating signals. The performance of the developed modified thermoregulation model is thoroughly analyzed under various conditions involving different environmental conditions, activity levels, and clothing types. The proposed model eliminates abrupt rise in the mean skin temperature and improves its prediction accuracy, notably reducing mean skin temperature RMSE in hot-humid conditions (0.66 °C vs. 0.85 °C) compared to the JOS-3 model. In hot-dry settings, improvements are significant, reducing the mean skin temperature and core temperature RMSE (0.48 °C vs. 0.06 °C and 0.05 °C vs. 0.02 °C, respectively). Overall, the modified thermoregulation model offers a reliable and accurate solution to analyze human physiological conditions for a wide range of practical problems.

Sporothrix and Sporotrichosis: A South African Perspective on a Growing Global Health Threat.

Sporotrichosis is a disease that arises from a fungal infection caused by members of the Ascomycete genus Sporothrix. The disease has a unique history in South Africa, due to an association with gold mines, where large numbers of mine workers were infected in the 1930s and 1940s. This was likely driven by hot humid conditions and timber supports used in these mine shafts. Furthermore, the disease is the most common subcutaneous fungal infection amongst the general population in South Africa, and the large number of immunocompromised individuals increases the public health risk in the country. Sporothrix is a genus in the Ophiostomatales, a fungal order primarily associated with environmental habitats. Unsurprisingly, sporotrichosis therefore has a documented history of sapronotic transmission from contaminated plant material. This review provides insights into the understanding of sporotrichosis and Sporothrix species, with a particular emphasis on the South African situation. We highlight knowledge gaps, particularly regarding the ecological factors influencing the occurrence and distribution of these species, which in turn affect the patterns of sporotrichosis. We also emphasise a need for ongoing proactive research and surveillance to prevent future outbreaks of sporotrichosis, an emerging disease with growing health implications worldwide.

The repeatability of a cycling exercise-heat stress test in a male population

IntroductionThere is considerable inter-individual variability in the physiological responses to environmental stressors and so to accurately assess and monitor changes in an individual's ability to cope with exercise-heat stress, a reliable protocol is required. The aim of this study was to examine the repeatability of a 90-min steady-state heat exercise bout with physiological and subjective variables, and performance during an incremental test to exhaustion post 90-min steady-state exercise. MethodSixteen mixed ability males (Age: 39 ± 15yrs; Height: 176.5 ± 4.8 cm; BM: 79.7 ± 10.3 kg; V˙O2peak: 46.2 ± 8.6 ml/kg/min; PPO: 309 ± 39W) who trained at least three times a week undertook two 90-min steady-state – followed by an incremental protocol to exhaustion – cycling heat stress tests (HSTs) in a hot-humid environment (35 °C, 60%RH). Heart rate (HR), rectal (T‾re) and skin temperature (T‾sk), rating of perceived exertion (RPE), thermal sensation (TS), and thermal comfort (TC) were measured throughout. Data was analysed using Intraclass Correlation Coefficients (ICC), technical error of measurement (TEM), Bland-Altman plots, t-tests, and Cohen's d to indicate magnitude of change. ResultsPhysiological variables indicated good repeatability evident through moderate to strong ICC ratings, low magnitudes of change (d), lower mean biases compared to their respective calculated TEMs, and statistical non-significance, except HR90, ₸sk90, and ₸sk. Hydration status showed good repeatability except for urine osmolality (osmu90) and resting urine colour (colu). Perceptual variables showed encouraging repeatability apart from resting TS and mean TS. Performance data showed good repeatability overall, however 11 participants progressed to the incremental test to exhaustion in the second visit compared to 7 in the first. ConclusionCurrent data demonstrated favourable physiological, perceptual, and performance repeatability during repeated cycling HSTs in hot-humid conditions. However, given more participants progressed to the incremental trial to exhaustion protocol in the second visit, at least one familiarisation trial may improve the reliability of exercise capacity assessment.

Pre-, Per- and post-cooling strategies used by competitive tennis players in hot dry and hot humid conditions.

This research investigated the pre-, per- and post cooling strategies used by competitive tennis players from various levels of play who occasionally train and compete in hot (>28°C) and humid (>60% rH), and dry (<60% rH) environments. 129 male tennis players (Mage = 24.9) competing at regional (N = 54), national (N = 30) and international (N = 45) levels, completed an online questionnaire regarding their use (i.e., timing, type, justification and effectiveness) of pre- (i.e., before practice), per- (i.e., during exercise) and post-cooling strategies when playing tennis in hot dry (HD) and hot humid (HH) conditions. Individual follow-up interviews were also carried on 3 participants to gain an in-depth understanding of the player's experience. Competitive tennis players used both internal and external cooling strategies to combat the negative effects of HD and HH conditions, but considered the HH to be more stressful than HD and experienced more heat-related illness in HH environments. International players used cold packs and cold towel more frequently than the regional and national players in hot environments, and used cold water immersion and cold vest more frequently than the latter in HH. Differences in strategy use were mostly observed during per-cooling where regional and national players more frequently used cold drinks than international players who more frequently used cold packs in HD and cold towel in HH conditions. Moreover the latter more frequently used cold towel, cold packs and cold water immersion as post-cooling strategies than regional players. When playing tennis in the heat, it is strongly recommended to employ cooling strategies to maintain health, limit declines in performance, and promote recovery. We also recommend improving education regarding the appropriate use and effectiveness of cooling strategies, and increasing their availability in tournaments.

Temporal effect of flaxseed oil in boar’s diet on semen quality, antioxidant status and in-vivo fertility under hot humid sub-tropical condition

The present study investigates the temporal effects of flaxseed supplementation on boar semen quality, antioxidant status, and in-vivo fertility under high-temperature humidity index (THI) conditions in a sub-tropical climate. Twelve Hampshire crossbreed boars were randomly assigned to control and treatment groups, with the treatment group receiving flaxseed oil supplementation. Semen samples were collected and analyzed for semen quality parameters, sperm kinematics, and antioxidant status. Fertility outcomes were assessed through in-vivo mating trials. Flaxseed supplementation resulted in time dependent significant improvements in semen volume, sperm concentration, total and progressive sperm motility, sperm quality parameters, and antioxidant status. Fertility outcomes, including farrowing rates and litter sizes, were also enhanced in the flaxseed-supplemented group. These findings highlight the potential of flaxseed supplementation to improve boar fertility under high ambient stress conditions, with implications for optimizing reproductive performance in swine production systems.

Exergy analysis of hybrid air-conditioning systems with different evaporative-cooling condensers under hot-humid climates

Evaporative cooling (EC) technology can effectively improve the energy efficiency of the mechanical vapor compression (MVC) system by enhancing the heat exchange capacity of its condenser. However, the current evaporative-cooling condenser system is usually only equipped with a single-stage evaporative cooler as the precooling unit, and these designs are mainly suitable for hot-dry conditions. In this study, three hybrid air-conditioning systems with different two-stage evaporative-cooling condenser configurations were proposed, one is single-condenser type and the other two are dual-condenser type, which are used to improve the exergy performance and adaptability of the evaporative condenser system under hot-humid climates. Then, the all systems were modeled via the distributed parametric method and analyzed comparatively based on the exergy method. A suitable exergy reference temperature at air saturation was discussed. Finally, the effect of four key parameters (ambient temperature and relative humidity, outdoor airflow rate and room heat load) was studied. The results showed that under the high temperature, relative humidity or room heat load conditions, the hybrid systems have a low exergy efficiency ratio (EXR) and high exergy efficiency (ηx,OEC). Among them, the newly countercurrent dual-condenser configuration (MVC-TSEC(C)) exhibits the best exergy performance under most hot-humid conditions. Compared to the conventional MVC system, the EXR and ηx,OEC of MVC-TSEC(C) increased by at most 35.0 % and 78.2 %, respectively. Moreover, its components like compressor, condenser and expansion valve have the maximum reduction rates of exergy destruction of 43.5 %, 17.2 % and 55.3 %, respectively.

Land Surface Longwave Radiation Retrieval from ASTER Clear-Sky Observations

Surface longwave radiation (SLR) plays a pivotal role in the Earth’s energy balance, influencing a range of environmental processes and climate dynamics. As the demand for high spatial resolution remote sensing products grows, there is an increasing need for accurate SLR retrieval with enhanced spatial detail. This study focuses on the development and validation of models to estimate SLR using measurements from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor. Given the limitations posed by fewer spectral bands and data products in ASTER compared to moderate-resolution sensors, the proposed approach combines an atmospheric radiative transfer model MODerate resolution atmospheric TRANsmission (MODTRAN) with the Light Gradient Boosting Machine algorithm to estimate SLR. The MODTRAN simulations were performed to construct a representative training dataset based on comprehensive global atmospheric profiles and surface emissivity spectra data. Global sensitivity analyses reveal that key inputs influencing the accuracy of SLR retrievals should reflect surface thermal radiative signals and near-surface atmospheric conditions. Validated against ground-based measurements, surface upward longwave radiation (SULR) and surface downward longwave radiation (SDLR) using ASTER thermal infrared bands and surface elevation estimations resulted in root mean square errors of 17.76 W/m2 and 25.36 W/m2, with biases of 3.42 W/m2 and 3.92 W/m2, respectively. Retrievals show systematic biases related to extreme temperature and moisture conditions, e.g., causing overestimation of SULR in hot humid conditions and underestimation of SDLR in arid conditions. While challenges persist, particularly in addressing atmospheric variables and cloud masking, this work lays a foundation for accurate SLR retrieval from high spatial resolution sensors like ASTER. The potential applications extend to upcoming satellite missions, such as the Landsat Next, and contribute to advancing high-resolution remote sensing capabilities for an improved understanding of Earth’s energy dynamics.

Aetiological Profile, Clinical Features and Risk Factors for Otomycosis in Dar Es Salaam, Tanzania: A Cross-Sectional Study.

Otomycosis is a commonly encountered otological disorder in otorhinolaryngology practice. It has several predisposing factors such as habitual use of cotton buds, water in the ear, hot humid atmospheric condition or high temperature. Diagnosis of otomycosis frequently relies on the patient's history, otoscopic examination and ascertained clinical features and therefore posing diagnostic and therapeutic challenges. Data on otomycosis in Tanzania are scarce. A hospital based descriptive cross-sectional study was conducted at a private hospital from January to June 2022 in Dar es Salaam, Tanzania. All the clinically diagnosed cases were enrolled in the study with typical symptoms and characteristic fungal debris in the external auditory canal. Data was collected using semi-structured questionnaires and analyzed using Statistical Package for Social Sciences version 23. A total of 250 patients were recruited in this study. Majority were females, 153(81.2%) while males were 97(38.8%). Otomycosis was found to be predominantly unilateral in 203 (81.2%) patients. The commonest presenting complaint was ear itching (94.0%) followed by earache (78.6%), hearing loss (75.6%), ear fullness (74.4%), ear discharge (61.2%) and ringing sensation (14.0%). Based on the type of fungal debris on Otoendoscopy, whitish debris was more predominant in 191 (76.4%) patients followed by yellowish debris, 37 (14.8%), blackish debris, 15 (6.0%) and mixed (whitish-black) debris in 7 (2.8%) patients. The commonest risk factor was earbud use (40.8%) and the least one was comorbid conditions (4.4%). Females were more affected by otomycosis. The commonest otological complaint was ear itching while the least one was ringing sensation. Unilateral presentation of otomycosis predominated and the left ear was more affected. The commonest type of fungal debris was whitish debris and the least one was the mixed type (whitish-black). The commonest risk factor for otomycosis was earbud use and the least was comorbid conditions.

ARCHITECTURAL SOLUTIONS OF SCHOOL BUILDINGS IN HOT-DRY AND HOT-HUMID REGIONS OF IRAN

Iran is characterized by a diverse climate spectrum, covering a temperate and humid climate in the north of the country and in the coastal areas of the Caspian Sea, a cold climate in the west and in the Zagros mountain range, as well as hot dry and hot-humid conditions prevailing in the central part , in the east, in the Persian Gulf region and in the south of the country. This article focuses on the analysis of architectural features of school buildings in hot-dry and hot-humid regions of Iran, taking into account the specifics of the climate of these areas. The main attention is paid to effective orientation of buildings in relation to the sun, optimization of air conditioning systems, adaptation of lighting to the needs of educational spaces, use of green spaces to create shading, as well as selection of the form and design of school interiors and selection of appropriate building materials. Architectural solutions determined by the climatic features of these regions are being considered in order to increase energy efficiency and ensure user comfort. Considering that schools belong to the category of buildings with a high level of energy consumption, such as electricity, water and gas, adaptation of architectural design to climatic conditions can significantly reduce energy costs. The article offers an overview of suitable climate-adapted architectural solutions for school buildings in certain regions of Iran, emphasizing the importance of an integrated design approach in the context of modern requirements for energy efficiency and sustainable development.

Mixed-Method Precooling Enhances Self-Paced 20-km Cycling Time-Trial Performance When Apparent Temperature Is >46 °C but May Not Be a Priority in

Precooling (PreC) may only benefit performance when thermal strain experienced by an individual is sufficiently high. We explored the effect of mixed-method PreC on 20-km cycling time-trial (CTT) performance under 3 different apparent temperatures (AT). On separate days, 12 trained or highly trained male cyclists/triathletes completed six 20-km CTTs in 3 different ATs: hot-dry (35 °C AT), moderately hot-humid (40 °C AT), and hot-humid (46 °C AT). All trials were preceded by 30minutes of mixed-method PreC or no PreC (control [CON]). Faster 2.5-km-split completion times occurred in PreC compared with CON in 46 °C AT (P = .02), but not in 40 °C AT (P = .62) or 35 °C AT (P = .57). PreC did not affect rectal and body temperature during the 20-km CTT. Skin temperature was lower throughout the CTT in PreC compared with CON in 46 °C AT (P = .01), but not in 40 °C AT (P = 1.00) and 35 °C AT (P = 1.00). Heart rate had a greater rate of increase during the CTT for PreC compared with CON in 46 °C AT (P = .01), but not in 40 °C AT (P = .57) and 35 °C AT (P = 1.00). Ratings of perceived exertion (P < .001) and thermal comfort (P = .04) were lower for PreC compared with CON in 46 °C AT only, while thermal sensation was not different between PreC and CON. Mixed-method PreC should be applied prior to 20-km CTTs conducted in hot-humid conditions (≥46 °C AT). Alternatively, mixed-method PreC may be a priority in moderately hot-humid (∼40 °C AT) conditions but should not be in hot-dry (∼35 °C AT) conditions for 20-km CTT.

No effect of a commercial carbohydrate‐menthol drink on thermal perceptual measures or 15‐min time trial performance compared to commercial carbohydrate drink in hot humid conditions

AbstractThis study assessed the effect of a commercial carbohydrate menthol drink on cycling time trial (TT) performance in hot and humid conditions compared with a carbohydrate only drink. Ten participants (5 women; V̇O2max: 52.3 ± 8.6 mL kg−1 min−1, Peak Power Output: 286 ± 56 W) completed a 40‐min cycling preload (50% V̇O2max) followed by a 15‐min self‐paced TT in hot (∼35°C) and humid (∼54%) conditions on two occasions (double blind, crossover design). Every 10‐min, 85 mL of carbohydrate (CHO; SIS GO Energy, 60 g h−1) or carbohydrate and menthol (CHO + MEN; SIS Turbo+ 60 g h−1, 0.01% menthol) was swilled (∼10‐s) and ingested. Rectal temperature (Trec) and heart rate (HR) were recorded throughout. Thermal sensation (TS), thermal comfort (TC) and rating of perceived exertion (RPE) were recorded every 5‐min. Taste and aftertaste were rated from very pleasant (+5) to very unpleasant (−5). TT performance (total work; kJ) was similar between CHO (153 kJ [95% CI: 129–177 kJ]) and CHO + MEN (151 kJ [128–178 kJ]). During preload exercise, Trec increased by ∼0.9°C and was similar at the end of the TT (∼38.20°C). Mean preload HR was ∼140 b min−1 in each condition and reached ∼177 b min−1 at the end of the TT. TC was rated as ‘much too warm’ and TS rated as ‘very hot’ in both conditions. Both conditions were ‘extremely hard’ (end point RPE ∼19). All participants preferred the taste and aftertaste of the CHO drink. The commercial carbohydrate menthol drink offered no additional ergogenic benefit compared to a carbohydrate only drink during cycling exercise performed in hot and humid conditions.

Hydration and evaporative water loss of lizards change in response to temperature and humidity acclimation.

Testing acclimation plasticity informs our understanding of organismal physiology and applies to conservation management amidst our rapidly changing climate. While there is a wealth of research on the plasticity of thermal and hydric physiology in response to temperature acclimation, there is a comparative gap for research on acclimation to different hydric regimes, as well as the interaction between water and temperature. We sought to fill this gap by acclimating Western Fence Lizards (Sceloporus occidentalis) to experimental climate conditions (crossed design of Hot or Cool, Dry or Humid) for eight days, and measuring cutaneous evaporative water loss (CEWL), plasma osmolality, hematocrit, and body mass before and after acclimation. CEWL changed plastically in response to the different climates, with lizards acclimated to Hot Humid conditions experiencing the greatest increase in CEWL. Change in CEWL among individuals was negatively related to treatment vapor pressure deficit and positively related to treatment water vapor pressure. Plasma osmolality, hematocrit, and body mass all showed greater changes in response to temperature than to humidity or vapor pressure deficit. CEWL and plasma osmolality were positively related across treatment groups before acclimation and within treatment groups after acclimation, but the two variables showed different responses to acclimation, suggesting that they are interrelated but governed by different mechanisms. This study is among few that assess more than one metric of hydric physiology and that test the interactive effects of temperature and humidity. Such measurements will be essential for predictive models of activity and survival for animals under climate change.

Effect of electric fan use in isolation or combined with ice slurry/cold water ingestion and lower-leg immersion in young men during intermittent physical activity in hot-humid conditions.

Using a randomized crossover protocol, 10 young men completed four 180min exposures (38°C, 60% relative humidity), alternating between 30min of walking and 30min of sitting where fluid or ice slurry were served. Participants underwent four trials: (i) 5mL·kg body mass-1 of 20°C water (CON); (ii) 5mL·kg body mass-1 of 20°C water+fan at 4m·s-1 (FAN); (iii) fan + 3mL·kg body mass-1 of ice slurry + 2mL·kg body mass-1 of 4°C water (FAN+ISCW); and (iv) FAN+ISCW+lower-leg immersion in 20°C water (FAN+ISCW+LLI). Sweat and body mass losses were higher with FAN than CON, FAN+ISCW, and FAN+ISCW+LLI. Mean and peak changes in Δrectal temperature, heart rate, and perceived heat and thirst from baseline were not statistically and practically different between FAN and CON. FAN+ISCW+LLI decreased sweat loss compared with FAN+ISCW and mean and peak changes in Δrectal temperature, heart rate, and perceived thirst compared with CON. FAN+ISCW+LLI also attenuated the changes in Δrectal temperature (peak) and thirst (mean and peak) compared with FAN. In conclusion, FAN slightly exacerbates fluid loss but does not attenuate the changes in Δrectal temperature, heart rate, and perceived heat and thirst during intermittent physical activity in hot-humid conditions. However, coupling ISCW or ISCW+LLI with the use of a fan attenuates the increase in these outcomes compared with no intervention and to a greater extent for rectal temperature and thirst when fan is coupled with ISCW+LLI than when it is used in isolation.

A 0.1% L-Menthol Mouth Swill in Elite Male Rugby Players Has Different Effects in Forwards and Backs.

Menthol mouth swills can improve endurance performance in the heat, which is attributed to attenuations in nonthermally derived thermal sensation (TS) and perception of effort. However, research in elite team-sport athletes is absent. Therefore, this study investigated the performance and TS responses to a 0.1% menthol mouth rinse (MR) or placebo (PLA) among elite male rugby union players. Twenty-seven (15 Forwards and 12 Backs) elite male Super Rugby players completed two 3-minute 15-a-side rugby-specific conditioning blocks, with MR or PLA provided at the start of training (baseline), at the start of each 3-minute block (swill 1 [S1] and swill 2 [S2]), and at the end of training (swill 3 [S3]). TS was assessed using the American Society of Heating, Refrigerating and Air-Conditioning Engineers 9-point Analog Sensation Scale after each swill and at baseline (preconditioning block). Acceptability was measured after baseline swill and S3 using a 5-question Likert scale. Physical performance was measured throughout training using global positioning system metrics. MR attenuated TS from baseline to S1 (P = .003, SD = 1.01) and S2 (P = .002, SD = 1.09) in Forwards only, compared with PLA. Acceptability was higher only for Forwards in MR versus PLA at baseline (P = .003, SD = 1.3) and S3 (P = .004, SD = 0.75). MR had no effect on physical performance metrics (P > .05). MR attenuated the rise in TS with higher acceptability at S1 and S3 (in Forwards only) with no effect on selected physical performance metrics. Longer-duration exercise (eg,a match) in hot-humid conditions eliciting markedly increased body temperatures could theoretically allow favorable changes in TS to enhance performance-these postulations warrant experimental investigation.

Environment assisted cyclic fatigue crack growth testing of polymer/inorganic laminates under strain energy release rate control

We focus on the development and implementation of an environmental (hot-dry or hot-humid air) testing methodology for adhesively bonded laminates under maximum strain energy release rate (SERR) control. The technique overcomes disadvantages of displacement- and force-controlled fatigue crack growth testing. Fracture mechanics based double cantilever beam (DCB) specimens comprising steel/epoxy- and glass/polyolefin-laminates were investigated using an electrodynamic test system with automated software control. Crack length was evaluated in-situ with a compliance calibration approach. User-defined SERR values were set with a control channel. The SERR was changed every 200,000 cycles or after exceeding crack length milestones. For steel/epoxy-laminates with an adhesive thickness of approximately 5 µm a good agreement of crack growth rates was obtained by displacement and SERR control. Moreover, the negative effect of humidity (50% vs. 10% rh) on the fatigue delamination resistance was confirmed at 60 °C. In contrast, significant deviations of crack growth rates under displacement and SERR control were deduced for glass/polyolefin-laminates with an adhesive thickness of 250 µm under hot-dry (60 °C, 1%rh) conditions. The deviations were attributed to differences in the damage zone size for the soft polymeric adhesive. Under hot-humid (60 °C, 80%rh) conditions a reasonable agreement of displacement and SERR controlled test data was observed and attributed to a less pronounced damage zone and a failure of the glass/polyolefin-laminates in an interfacial manner.

Effect of rapid changes in environmental conditions on canine detection of methyl benzoate

Detection canines are utilized worldwide in some of the most challenging field conditions for the detection of narcotics, explosives, and other targets. Much remains unknown, however, how these challenging conditions impact detection canine performance. Anecdotal evidence suggests that detection dogs require a “start-up” period – a short duration of time working – before performing optimally. These dogs commonly rest in climate-controlled settings (such as in a climate-controlled vehicle) and quickly transition to searches in contrasting conditions, which may exacerbate the issue. Accordingly, this study sought to quantify the magnitude and duration of the start-up period, and to identify any further effects on performance due to rapid transitions into extreme temperature/humidity conditions. The detection threshold of seven dogs was established for methyl benzoate (an odor simulant of illicit cocaine) under standard conditions using an air dilution olfactometer. A series of evaluations were then conducted to determine changes in this threshold when the dogs were rapidly transitioned from standard conditions to one of six temperature/humidity conditions - hot-humid, warm-humid, hot-dry, standard, cold-dry and cold-humid. Temperatures ranged from 0 to 40 ºC and relative humidity ranged from <40 % to >85 %. Changes in detection threshold were measured via a series of three “probes” of six trials, with a 2 min inter-probe interval to habituate to environmental conditions. Probes started at the dogs’ estimated threshold and decreased in concentration based on correct performance. Overall, dogs showed substantial decrements in the hot-humid condition followed by moderate decrements in hot-dry and warm-humid conditions. Cold conditions did not produce statistically significant decrements. In addition, the data indicate that a start-up period does exist when canines transition from a state of rest directly into a search assignment. The duration of this start-up period was initially measured to be several minutes long; but after the first series of testing (approximately a couple months of training/testing), the dogs only exhibited a decrement in performance on the first trial of a session. Overall, the results suggest that environmental conditions and a brief “start-up” effect should be considered as important variables that can impact detection canine performance.

Thermoregulatory responses during road races in hot-humid conditions at the 2019 Athletics World Championships.

The purpose of this study was to characterize thermoregulatory and performance responses of elite road-race athletes, while competing in hot, humid, night-time conditions during the 2019 IAAF World Athletic Championships. Male and female athletes, competing in the 20 km racewalk (n = 20 males, 24 females), 50 km racewalk (n = 19 males, 8 females), and marathon (n = 15 males, 22 females) participated. Exposed mean skin (Tsk) and continuous core body (Tc) temperature were recorded with infrared thermography and ingestible telemetry pill, respectively. The range of ambient conditions (recorded roadside) was 29.3°C-32.7°C air temperature, 46%-81% relative humidity, 0.1-1.7 m·s-1 air velocity, and 23.5°C-30.6°C wet bulb globe temperature. Tc increased by 1.5 ± 0.1°C but mean Tsk decreased by 1.5 ± 0.4°C over the duration of the races. Tsk and Tc changed most rapidly at the start of the races and then plateaued, with Tc showing a rapid increase again at the end, in a pattern mirroring pacing. Performance times were between 3% and 20% (mean = 113 ± 6%) longer during the championships compared with the personal best (PB) of athletes. Overall mean performance relative to PB was correlated with the wet-bulb globe temperature (WBGT) of each race (R2 = 0.89), but not with thermophysiological variables (R2 ≤ 0.3). As previously reported in exercise heat stress, in this field study Tc rose with exercise duration, whereas Tsk showed a decline. The latter contradicts the commonly recorded rise and plateau in laboratory studies at similar ambient temperatures but without realistic air movement.NEW & NOTEWORTHY This paper provides a kinetic observation of both core and skin temperatures in 108 elite athletes, during various outdoor competition events, adding to the very limited data so far available in the literature taken during elite competitions. The field skin temperature findings contrast previous laboratory findings, likely due to differences in relative air velocity and its impact on the evaporation of sweat. The rapid rise in skin temperature following cessation of exercise highlights the importance of infrared thermography measurements being taken during motion, not during breaks, when being used as a measurement of skin temperature during exercise.

Evaluation of production performance of Binjharpuri cattle of Odisha

Binjharpuri, a dual purpose indigenous breed of Odisha is commonly reared for its various advantages, viz. optimum milk production in low input management system, excellent draft ability in hot humid climate condition and heat resistance ability. In the present study, attempt was made to evaluate production performance along with influence of non- genetic effects such as location, lactation order and season of calving on production traits of binjharpuri cattle. The overall average least square means along with standard error for lactation milk yield, average daily milk yield, peak yield, lactation length and dry period were found to be 974.490±6.788 kg, 3.557±0.023 kg, 4.633±0.021 kg, 274.444±1.249 days and 121.913±0.611 days, respectively. Location had highly significant effect on lactation milk yield, average daily milk yield, lactation length and dry period, whereas non-significant effect on peak yield. Lactation order too had highly significant effect on the traits considered under study. Season of calving had highly significant effect on lactation milk yield, average daily milk yield; significant effect on lactation length whereas non-significant effect on peak yield and dry period. Significant influence of non-genetic factors and significant variations in traits under study is suggestive that remarkable improvement in the Binjharpuri cattle populace can be targeted through better management and by nurturing effective breeding strategies.

Geochemical characteristics of the Rajmahal coals in Dhulia North Block, Eastern India: implication to their utilization and environment.

The borehole coal samples of Dhulia North Block from the Rajmahal Basin, Eastern India, were systematically analyzed based on the chemical composition and concentration of major and trace elements (including rare earth elements, REEs) to assess the distribution of REEs and their environmental implications with utilization potential. TheDhulia North Block coals are characterized by the predominant majoroxides of SiO2, Al2O3, and Fe2O3, accounting for 94% of the total ash composition, indicating the presence of quartz, clay-rich minerals, and pyrite. Compared with the average world coal ash, the total REE content in the analyzed samples ranged from 341.0 to 810.4ppm, which is substantially higher. Hot humid climate conditions with intermediate igneous source rocks of the basin were demonstrated by the major oxide ratios (Al2O3/TiO2 < 20) and plots of TiO2 with Al2O3 and Zr. The redox-sensitive elements such as V, Ni, Cr, and Co found in the Dhulia North Block coal indicate that an oxic sedimentary environment existed in the basin when coal was formed. The low sulfur content (1% in most samples) indicates freshwater conditions in the basin at the time of organic matter deposition. The outlook coefficient (Coutl) varies between0.7 and 1.6, indicating that the Dhulia North Block coals are a prospective source of REEs. The Dhulia North Block coals are characterized by low H/C and O/C atomic ratios ranging from 0.56 to 0.90 and 0.10 to 0.22, respectively, and contain type-III kerogens, indicating gas-prone source rock. Further, the basic-to-acid oxide ratio suggested that Dhulia North Block coals were suitable for utilization during combustion processes.