Optimized Machine Learning Models for Predicting Core Body Temperature in Dairy Cows: Enhancing Accuracy and Interpretability for Practical Livestock Management.

Heat stress poses a significant challenge to livestock farming, particularly affecting the health and productivity of high-yield dairy cows. This study develops a machine learning framework aimed at predicting the core body temperature (CBT) of dairy cows to enable more effective heat stress management and enhance animal welfare. The dataset includes 3005 records of physiological data from real-world production environments, encompassing environmental parameters, individual animal characteristics, and infrared temperature measurements. Employed machine learning algorithms include elastic net (EN), artificial neural networks (ANN), random forests (RF), extreme gradient boosting (XGBoost), light gradient boosting machine (LightGBM), and CatBoost, alongside several optimization algorithms such as Bayesian optimization (BO) and grey wolf optimizer (GWO) to refine model performance through hyperparameter tuning. Comparative analysis of various feature sets reveals that the feature set incorporating the average infrared temperature of the trunk (IRTave_TK) excels in CBT prediction, achieving a coefficient of determination (R2) value of 0.516, mean absolute error (MAE) of 0.239 °C, and root mean square error (RMSE) of 0.302 °C. Further analysis shows that the GWO-XGBoost model surpasses others in predictive accuracy with an R2 value of 0.540, RMSE as low as 0.294 °C, and MAE of just 0.232 °C, and leads in computational efficiency with an optimization time of merely 2.41 s-approximately 4500 times faster than the highest accuracy model. Through SHAP (SHapley Additive exPlanations) analysis, IRTave_TK, time zone (TZ), days in lactation (DOL), and body posture (BP) are identified as the four most critical factors in predicting CBT, and the interaction effects of IRTave_TK with other features such as body posture and time periods are unveiled. This study provides technological support for livestock management, facilitating the development and optimization of predictive models to implement timely and effective interventions, thereby maintaining the health and productivity of dairy cows.

The role of Kupffer cells in microbiota-brain communication: Sleep and fever signaling in response to lipopolysaccharide.

Microbial molecules translocated from the intestinal lumen into the host's internal environment play a role in various physiological functions. Previously, we identified that butyrate, a short-chain fatty acid produced by intestinal bacteria, lipoteichoic acid, a cell wall component of gram-positive bacteria, and lipopolysaccharide (LPS), a cell wall component of gram-negative bacteria, induce sleep when their naturally occurring translocation is mimicked by direct delivery into the portal vein. Our findings suggested that these microbial molecules exert their sleep-promoting effects within the hepatoportal region. In the present experiments, we tested the hypothesis that resident liver macrophages, known as Kupffer cells, play a crucial role in the LPS-responsive, sleep-promoting mechanisms within the hepatoportal region. Intraportal administration of LPS induced increased sleep and fever in control rats. Remarkably, in Kupffer cell-depleted animals, both of these responses were significantly suppressed. These findings highlight the potential role of Kupffer cells in mediating the non-rapid-eye movement sleep-promoting and febrile effects of LPS translocated from the intestinal microbiota into the portal circulation. The strategic location of Kupffer cells within the hepatoportal region, coupled with their ability to rapidly take up LPS and other microbial molecules, together with their high secretory activity of multiple signaling molecules, underlie their key role in the communication between the intestinal microbiota and the brain.

Change in body temperature, not acute-phase reaction, predict anti-Osteoporosis efficacy after the first administration of Zoledronic acid: a prospective observational cohort study.

BACKGROUND: Acute-phase reactions (APRs) are common among people treated for the first time with zoledronate (ZOL). The current view is that both the APRs caused by ZOL and its efficacy are related to the mevalonic acid pathway. However, the relationship between APRs and ZOL efficacy remains unclear. METHODS: This was a prospective observational cohort study involving postmenopausal women with osteoporosis in Shanghai, China, for 1 year. A total of 108 patients with an average age of 67.4 ± 5.8 years were treated with 5 mg intravenous ZOL for the first time. Data on demographic characteristics, APRs, blood counts, bone turnover markers, including C-telopeptide collagen crosslinks (CTX) and N-terminal propeptide of type 1 collagen (PINP), and bone mineral density (BMD) were collected. RESULTS: (1) The results did not reveal a relationship between APRs and changes in bone turnover markers and BMD but showed that changes in body temperature (T) within 3 days after administration were positively correlated with changes in the BMD of the LS at Month 12 (ß = 0.279 P = 0.034). (2) This effect was mediated mainly by changes in serum CTX (b = 0.046, 95% CI [0.0010-0.0091]). (3) The ROC curve revealed that when T increased by 1.95 °C, the sensitivity and specificity of identifying clinically important changes in LS BMD after 1 year were optimized. CONCLUSIONS: In this study, we tested the hypothesis that people with elevated body T after initial ZOL treatment had greater improvements in BMD and better outcomes. TRIAL REGISTRATION: NCT, NCT03158246. Registered 18/05/2017.

Heat stress induces a three-phase thermoregulatory response in different hot and humid environments in rats.

As global warming intensifies, heat waves occur more frequently around the world. Heat stress from hot and humid environments poses a significant threat to human health. It can cause a significant increase in core body temperature (CBT), and even lead to life-threatening heat stroke. Extremely high CBT is considered the most important clinical symptom and prognostic indicator of heat stroke. To study it, we implanted temperature-monitoring capsules into the abdominal cavities of rats to measure their CBT values. The rats were then exposed to different hot and humid environments to monitor the resultant changes in their CBTs. The results showed that heat stress could induce a three-phase thermoregulatory response in rats under different conditions. A temperature plateau was observed as part of the three-phase thermoregulatory response, at a similar CBT across different conditions. The duration of this plateau can reflect the thermotolerance of rats in hot and humid environments. The third stage of the three-phase thermoregulatory response reflects the pathogenesis of heat stroke, which may present the key stage of heat injury. Moreover, a certain range of humidity did not affect the thermoregulatory responses of rats, but exerted a significant impact once a certain threshold was reached. In this study, the CBTs of the rats in different environments were monitored to characterize their thermoregulatory responses under heat stress. In particular, the discovery of the plateau phase and humidity threshold may help to better understand the effects of high temperature and humidity conditions on living organisms.

Levels of C-Reactive Protein and Body Temperature Elevation During Neutropenia Predict Engraftment and Non-Relapse Mortality for Unrelated Single-Unit Cord Blood Transplantation in Adults.

Cord blood transplantation (CBT) presents unique challenges related to inflammation during neutropenia, such as mucosal damage, infections, and the potential development of pre-engraftment syndrome or pre-engraftment immune reaction. These factors can contribute to significant inflammation and infection shortly after CBT. However, the effect of severe inflammation during neutropenia, specifically elevated C-reactive protein (CRP) level and body temperature, on post-transplant outcomes after CBT remains unclear. This retrospective study aimed to investigate the association between maximum CRP level, maximum body temperature during neutropenia, and post-transplantation outcomes in adult patients undergoing single-unit CBT. We retrospectively evaluated the impact of maximum CRP level and maximum body temperature during neutropenia on post-transplantation outcomes in adults who underwent single-unit unrelated CBT between 1998 and 2023 at our institution. A total of 336 adult patients were included in this study. The median maximum CRP level before neutrophil recovery was 7.75 mg/dL (interquartile range [IQR], 4.70 to 12.05 mg/dL) at a median of 14 d (IQR, 8 to 16 d). The median maximum body temperature before neutrophil recovery was 39.5°C (IQR, 39.0 to 40.0°C) at a median of 15 d (IQR, 12 to 17 d). In the multivariate analysis, a maximum CRP level≥20 mg/dL was significantly associated with lower neutrophil recovery (hazard ratio [HR], 0.37; 95% confidence interval [CI], 0.23 to 0.59; P < .001), lower platelet recovery (HR, 0.28; 95% CI, 0.16 to 0.48; P < .001), and a higher incidence of veno-occlusive disease/sinusoidal obstruction syndrome (HR, 16.42; 95% CI, 4.11 to 65.54; P < .001), which resulted in higher non-relapse mortality (NRM) (HR, 5.16; 95% CI, 2.62 to 10.15; P < .001) and worse overall survival (HR, 2.81; 95% CI, 1.66 to 4.78; P < .001). Similarly, a maximum body temperature≥40.5°C was significantly associated with lower neutrophil recovery (HR, 0.51; 95% CI, 0.33 to 0.79; P = .002), lower platelet recovery (HR, 0.55; 95% CI, 0.38 to 0.79; P = .001), higher incidence of grades III to IV acute GVHD (HR, 2.93; 95% CI, 1.24 to 6.88; P = .013), and extensive chronic GVHD (HR, 2.47; 95% CI, 1.22 to 4.97; P = .011), which resulted in higher NRM (HR, 3.43; 95% CI, 1.53 to 7.67; P = .002). Maximum CRP level and maximum body temperature during neutropenia were significantly associated with lower hematopoietic recovery and higher NRM following single-unit CBT in adults. Further studies are warranted to explore early intervention strategies aimed at preventing severe inflammation and improving post-transplant outcomes in single-unit CBT.

Temperature-dependence of regional heterothermy in a diminutive ectotherm.

Regional heterothermy describes when body regions differ in temperature, which can have important ramifications for performance because most biological processes are temperature-dependent. However, the relationship between regional heterothermy and environmental temperature is not well known, particularly for ectotherms. The relationship between environmental heterogeneity and regional heterothermy might also yield insight into how the latter is regulated. We examined the thermal dependence of regional heterothermy (between the head and the cloaca) in live ring-necked snakes (Diadophis punctatus) in both the lab and the field, as well as in one dead and preserved individual. We found that the magnitude of the head-cloaca difference declined with average environmental temperature, that the relationship between head temperature and ambient temperature differed from that of cloaca temperature and ambient temperature, and that the preserved snake specimen did not display a consistent head-cloaca temperature difference. Our results suggest that 1) cloacal and head temperatures are regulated differently, 2) the head-cloaca temperature difference is not merely due to differences in the material properties of the head and cloaca, and 3) may arise from altered circulation and perhaps even endogenous heat-generating mechanisms. Our results also suggest that the thermal dependence of regional heterothermy likely has ramifications for organismal function.

Impact of Prewarming on Maintaining Perioperative Body Temperature: A Randomized Clinical Trial.

PURPOSE: To determine the prewarming effect on body temperature in the perioperative period of patients undergoing conventional abdominal surgery and the level of thermal comfort. DESIGN: A randomized controlled clinical trial. METHODS: A Brazilian oncology hospital located in São Paulo. A total of 99 patients aged 18 years or over undergoing elective conventional abdominal surgeries, with a minimum duration of 1 hour of anesthesia. The study was carried out from 2019 to 2021. Patients were randomized into 3 groups: prewarming with a blanket and cotton sheet (control; n = 33); prewarming with a forced-air warming system for 20 minutes (intervention 1; n = 33); prewarming with a forced-air warming system for 30 minutes (intervention 2; n = 33). Central temperature was measured by a zero-heat-flux temperature sensor every 20 minutes from the preoperative period until the surgery end time. The level of thermal comfort was determined through self-report during the preanesthetic and postanesthetic periods. FINDINGS: There was a significant difference between the temperatures between the groups (P = .048), with evidence of greater benefit in maintaining the temperature in the group that received the prewarming intervention for 20 minutes. There was no significant difference between the percentage of temperatures below 36 °C among the groups (P = .135). Patients in the intervention groups were more comfortable during the postanesthetic recovery period than those in the control group (P = .048). Only 7 (8.24%) patients had postoperative chills (P = .399) and more than half of these incidents occurred in the control group (4; 13.3%). CONCLUSIONS: Prewarming for 20 minutes obtained the best results, showing the lowest average of temperature episodes below 36 °C during the intraoperative period and greater thermal comfort as reported by patients.

Content validation of the NANDA-I nursing diagnosis risk for perioperative hypothermia (00254).

PURPOSE: The objectives of this study were to refine and validate the NANDA-I nursing diagnosis risk for perioperative hypothermia (RPH) (00254). METHODS: A quantitative, descriptive study was carried out according to the adapted diagnostic content validation model by Fehring. Data from a previously conducted literature study were triangulated with expert validation data to examine the nursing diagnosis RPH as well as potentially suggested new factors resulted from the literature review. In addition, the Wisdom of Crowds model was also considered. A nonprobability sampling technique, including purposive and snowball sampling methods, was used to recruit a panel of nurse experts. An anonymous and standardized questionnaire was developed in three languages for data collection. For validation, descriptive statistics, weighted ratios, and a one-sample T-test were used. RESULTS: Ninety-two nurse experts from seven countries and three continents participated in this study. Fifty-eight nurse experts (63%) were female, and 33 (36%) were male, with a mean age of 42.26 years and 19.22 years of working experience. The diagnosis label, definition, 4 out of 5 risk factors (RF), 6 out of 14 at-risk populations (ARPs), and 5 out of 9 associated conditions (ACs) were classified as major. One RF, eight ARP, and four ACs were considered minor. In addition, the experts validated 1 RF, 5 ARP, and 12 ACs from a previous literature study at least minor. CONCLUSIONS: The nursing diagnosis RPH (00254) could be confirmed by specialized experts. No RF, ARP, or AC of the current nursing diagnosis needed to be rejected, and the added diagnostic indicators increased the robustness of the diagnosis. IMPLICATIONS FOR NURSING PRACTICE: A precise concept of the nursing diagnosis RPH improves nurses' clinical reasoning and strengthens an individualized, evidence-based care plan.

The effect of forced-air warming blanket position during spinal surgery on patients' intra-operative body temperature.

BACKGROUND: The use of body-warming systems is recommended by international anaesthesia societies for patients undergoing surgery. Limited research is however available on the influence of positioning of forced-air warming blankets for patients undergoing spinal surgery. This study aimed to investigate how patients' intra-operative body temperature was affected by the position of forced-air warming blankets while undergoing spinal surgery on a spinal table. DESIGN: A randomized comparative experimental study was conducted with 60 adult patients undergoing posterior spinal surgery. METHODS: Patients were randomized into full underbody (n = 30) or surgical access (n = 30) forced-air warming blanket groups. Intra-operative body temperature was recorded at regular time intervals. The student's T-test, Chi-square, and MANOVA tests were performed to determine the differences between the two groups. RESULTS: Intraoperative hypothermia was significantly lower in the full underbody group than in the surgical access group (p = 0.020). The change in body temperature differed significantly between the two groups from 15 min until 240 min, with a mean difference of 0.5 °C. CONCLUSION: The full underbody position of the forced-air warming blanket was effective for maintaining normal range core body temperature. The use of full underbody forced-air warming blanket for spinal surgery when patients are positioned on a spinal table in a prone position is recommended.

Infrared thermometry for detecting estrus and pregnancy in Holstein cows.

Efficient reproductive management is paramount in enhancing the productivity and welfare of dairy cows. This study investigates the effects of pregnancy status, seasonal variations, and diurnal shifts on the body temperature of different body parts in dairy cows. Using a structured approach, cows were categorized based on pregnancy status (pregnant vs. control) or estrous status (estrous vs. control), season (winter, spring, summer), and time of day (morning, noon, evening). The analysis revealed that pregnancy and estrous statuses significantly affect the body temperature, with pregnant and estrous cows displaying higher temperatures (39.0 ± 0.03 and 38.0 ± 0.06 °C, respectively) than controls (37.1 ± 0.06 °C; p < 0.01). Seasonal impacts were also notable, with the highest temperatures observed in summer (38.3 ± 0.07 °C) followed by spring (38.1 ± 0.09 °C) and winter (37.7 ± 0.06 °C; p < 0.01), indicating a strong environmental influence on physiological responses. Furthermore, diurnal analysis indicated temperature fluctuations throughout the day, peaking at noon (38.1 ± 0.09 °C; p < 0.05) compared to morning and evening. High positive correlations were observed between the measured temperatures in different areas and rectal and vaginal temperatures, suggesting the skin surface is ideal for assessing thermal changes. These findings underscore the critical interplay between an animal's physiological state and external environmental factors in managing dairy cow health and reproduction. The study highlights the potential of non-invasive temperature monitoring as a tool for optimizing reproductive management and underscores the necessity of accounting for environmental and physiological variations in dairy management practices.

Detection Dogs Working in Hot Climates: The Influence on Thermoregulation and Fecal Consistency.

Body temperature is an important physiological parameter that influences the performance of working dogs. The main cooling mechanism in dogs is panting to support evaporative cooling, which reduces the dog's ability to detect scents. In this study, we investigated the general body condition of four detection dogs searching for cheetah scats in a hot environment in northern Kenya. We evaluated the effect on the dog's body temperature post-work in the short term (within hours) and long term (12-24 h). The fecal consistency and mean body temperature of the investigated dogs differed significantly between individuals but not between locations (moderate Nairobi and hot Samburu). On the morning after fieldwork, the dogs showed a significantly increased body temperature (37.9 ± 0.8 °C) compared to resting days (37.5 ± 2.2 °C). In the short term, on the first day of fieldwork, the dog's body temperature (n = 2) decreased after 10 min of rest. On the second consecutive day of fieldwork, the 10-min recovery period was too short, and the body temperature did not decrease significantly. Our data showed that the use of detection dogs in hot conditions is possible and useful but requires increased attention to prevent heat-related illness.

The Effect of a Synthetic-Grass Sport Surface on Physiology and Perception During Intermittent Exercise in Hot Conditions.

PURPOSE: The current study aimed to determine the effect of a synthetic-grass sport surface on core body temperature, skin temperature, heart rate, thermal sensation, thermal comfort, and rating of perceived exertion (RPE) during intermittent exercise in hot conditions. METHODS: Using a randomized crossover design, 13 trained/developmental team-sport athletes completed two 50-minute standardized intermittent running protocols on a synthetic and a natural-grass surface, on separate days (control-condition air temperature 32.6 °C [1.3 °C], relative humidity 43.2% [5.3%]). RESULTS: Final skin temperature was significantly higher on synthetic compared with natural grass at the calf (40.1 °C [2.5 °C] vs 33.4 °C [0.6 °C]; P < .001), shoulder (36.6 °C [1.7 °C] vs 33.7 °C [0.7 °C]; P < .001), and chest (33.2 °C [1.1 °C] vs 31.8 °C [1.2 °C]; P = .02). Thermal sensation (median: 2.3; interquartile range [0.5] vs 2.2 [0.5], P = .03) and sweat rate (1.5 [0.4] L·h-1 vs 1.2 [0.3] L·h-1; P = .02) were also significantly higher on synthetic grass. While final core body temperature was significantly higher on the natural than synthetic grass (38.4 °C [0.3 °C] vs 38.2 °C [0.4 °C]), there were no significant differences in delta core temperature, as well as heart rate, thermal comfort, or RPE. CONCLUSIONS: Higher skin temperatures, thermal sensation, and sweat rates suggest that exercising on synthetic grass in hot conditions may increase some markers of heat strain during exercise. However, delta core body temperature, heart rate, thermal comfort, and RPE remained unaffected.

Predicting Neutropenic Sepsis in Patients with Hematologic Malignancy: A Retrospective Case-Control Study.

Neutropenic sepsis (NS) is one of the leading causes of death among patients with hematologic malignancies. Identifying its predictive factors is fundamental for early detection. Few studies have evaluated the predictive factors in relation to microbial infection confirmation, which is clinically important for initiating sepsis treatment. This study aimed to determine whether selected biomarkers (i.e., body temperature, C-reactive protein, albumin, procalcitonin), treatment-related characteristics (i.e., diagnosis, duration of neutropenia, treatment modality), and infection-related characteristics (i.e., infection source, causative organisms) can predict NS in patients with hematologic malignancies. We also aimed to identify the optimal predictive cutoff points for these parameters. This retrospective case-control study used the data from a total of 163 patients (58 in the sepsis group and 105 in the non-sepsis group). We collected data with reference to the day of specimen collection, with which microbial infection was confirmed. Multiple logistic regression was used to determine predictive risk factors and the area under the curve (AUC) of the receiver operating characteristic for the optimal predictive cutoff points. The independent predictors of NS were average body temperature during a fever episode and procalcitonin level. The odds for NS rose by 9.97 times with every 1°C rise in average body temperature (95% confidence interval, CI [1.33, 75.05]) and by 2.09 times with every 1 ng/mL rise in the procalcitonin level (95% CI [1.08, 4.04]). Average body temperature (AUC = 0.77, 95% CI [0.68, 0.87]) and procalcitonin levels (AUC = 0.71, 95% CI [0.59, 0.84]) have fair accuracy for predicting NS, with the optimal cutoff points of 37.9°C and 0.55 ng/mL, respectively. This study found that average body temperature during a fever episode and procalcitonin are useful in predicting NS. Thus, nurses should carefully monitor body temperature and procalcitonin levels in patients with hematologic malignancies to detect the onset of NS.

Seasonal variation of behavioural thermoregulation in a fossorial salamander (Ambystoma maculatum).

Temperature seasonality plays a pivotal role in shaping the thermal biology of ectotherms. However, we still have a limited understanding of how ectotherms maintain thermal balance in the face of varying temperatures, especially in fossorial species. Due to thermal buffering underground, thermal ecology theory predicts relaxed selection pressure over thermoregulation in fossorial ectotherms. As a result, fossorial ectotherms typically show low thermoregulatory precision and low evidence of thermotactic behaviours in laboratory thermal gradients. Here, we evaluated how temperature selection (T sel) and associated behaviours differed between seasons in a fossorial amphibian, the spotted salamander (Ambystoma maculatum). By comparing thermoregulatory parameters between the active and overwintering seasons, we show that A. maculatum engages in active behavioural thermoregulation despite being fossorial. In both seasons, T sel was consistently offset higher than acclimatization temperatures. Thermoregulation differed between seasons, with salamanders having higher T sel and showing greater evidence of thermophilic behaviours in the active compared with the overwintering season. Additionally, our work lends support to experimental assumptions commonly made but seldom tested in thermal biology studies. Ultimately, our study demonstrates that the combination of careful behavioural and thermal biology measurements is a necessary step to better understand the mechanisms that underlie body temperature control in amphibians.

Regulation of Neural Functions by Brain Temperature and Thermo-TRP Channels.

Body temperature is an important determinant in regulating the activities of animals. In humans, a mild 0.5 °C hyperthermia can cause headaches, demonstrating that the maintenance of normal body temperature is a key for our health. In a more extreme example, accidental acute hypothermia can lead to severe shivering, loss of consciousness, or death, although the details of these mechanisms are poorly understood. We previously found that the TRPV4 ion channel is constitutively activated by normal body temperature. The activation threshold of TRPV4 is >34 °C in the brain, which enables TRPV4 to convert thermal information into cellular signaling. Here we review the data that describe how the deletion of TRPV4 evokes abnormal behavior in mice. These studies demonstrate that the maintenance of body temperature and the sensory system for detecting body temperature, such as via TRPV4, are critical components for normal cellular function. Moreover, abnormal TRPV4 activation exacerbates cell death, epilepsy, stroke, or brain edema. Notably, TRPV4 can detect mechanical stimuli and contributes to various neural functions similar to the mechanosensitive characteristics of TRPV2. In this review, I summarize the findings related to TRPV2/TRPV4 and neural functions.

Central Mechanisms of Thermoregulation and Fever in Mammals.

Thermoregulation is a fundamental homeostatic function in mammals mediated by the central nervous system. The framework of the central circuitry for thermoregulation lies in the hypothalamus and brainstem. The preoptic area (POA) of the hypothalamus integrates cutaneous and central thermosensory information into efferent control signals that regulate excitatory descending pathways through the dorsomedial hypothalamus (DMH) and rostral medullary raphe region (rMR). The cutaneous thermosensory feedforward signals are delivered to the POA by afferent pathways through the lateral parabrachial nucleus, while the central monitoring of body core temperature is primarily mediated by warm-sensitive neurons in the POA for negative feedback regulation. Prostaglandin E2, a pyrogenic mediator produced in response to infection, acts on the POA to trigger fever. Recent studies have revealed that this circuitry also functions for physiological responses to psychological stress and starvation. Master psychological stress signaling from the medial prefrontal cortex to the DMH has been discovered to drive a variety of physiological responses for stress coping, including hyperthermia. During starvation, hunger signaling from the hypothalamus was found to activate medullary reticular neurons, which then suppress thermogenic sympathetic outflows from the rMR for energy saving. This thermoregulatory circuit represents a fundamental mechanism of the central regulation for homeostasis.

Circadian Clock and Body Temperature.

The circadian fluctuation of body temperature is one of the most prominent and stable outputs of the circadian clock and plays an important role in maintaining optimal day-night energy homeostasis. The body temperature of homothermic animals is not strictly constant, but it shows daily oscillation within a range of 1-3 °C, which is sufficient to synchronize the clocks of peripheral tissues throughout the body. The thermal entrainment mechanisms of the clock are partly mediated by the action of the heat shock transcription factor and cold-inducible RNA-binding protein-both have the ability to affect clock gene expression. Body temperature in the poikilotherms is not completely passive to the ambient temperature change; they can travel to the place of preferred temperature in a manner depending on the time of their endogenous clock. Based on this behavior-level thermoregulation, flies exhibit a clear body temperature cycle. Noticeably, flies and mice share the same molecular circuit for the controlled body temperature; in both species, the calcitonin receptors participate in the formation of body temperature rhythms during the active phase and exhibit rather specific expression in subsets of clock neurons in the brain. We summarize knowledge on mutual relationships between body temperature regulation and the circadian clock.

Behavioral and hormonal responses in the defensive repertoire during provocation in captive monocled cobra (Naja kaouthia).

The hooding behavior exhibited by cobras is a distinct defensive mechanism against predators, encompassing both visual and auditory displays. This behavior can be triggered by natural predators or humans. Considering that human provocation may potentially stimulate the hypothalamic-pituitary-adrenal (HPA) axis, the present study aimed to determine the pattern of the HPA axis response following human provocation-induced hooding behavior (PV) and provide a detailed analysis of the behavioral PV displays. Our primary hypothesis was that a 5-minute PV could activate the HPA axis to a degree comparable to that in the restraint-induced stress model (RS). The PV, RS-1 (1-minute), and RS-5 (5-minute) restraint models indeed activated the HPA axis. However, the pattern of plasma corticosteroid (CORT), but not arginine vasotocin, in the PV group differed from that in the RS-1 and RS-2 groups. The present study revealed the behavioral components of the PV. The first component appeared to be related to an increase in apparent size that is an intimidation display, while the second hissing and striking component consisted of a bluff charge. Moreover, no correlation was observed between the pattern of plasma CORT and any specific PV display. Finally, the body temperature (Tb) of cobras from RS-5 gradually increased, while the Tb of cobras from PV (5 min) remained unchanged. In conclusion, the activation of the HPA axis emerges as the main physiological response after human provocation. Within 5 min of provocation, the cobras' hooding behavior comprised two display components that were not related to the pattern of plasma CORT.

A Method for Predicting Ultradian Body Temperature Rhythms in Small Animals.

It has been found that the intraday dynamics of body temperature in small mammal and bird species on the adjacent day are similar. Therefore, by focusing on the body temperature dynamics of the previous day, it is possible to predict with a high degree of accuracy the periods of increase and decrease in body temperature for the current day. This phenomenon was observed when animals were kept under natural illumination and under artificial illumination when the phase of the intrinsic circadian rhythm shifted by 1-2 h every day. When analyzing this phenomenon in birds, it has been shown that the best match for body temperature dynamics occurs when comparing adjacent days based on sidereal days (a period of 23 h and 56 min). Over time, after several days, the daily patterns of body temperature fluctuation take on a completely different form and frequency. These facts suggest a connection between ultradian rhythms and the rotation of the Earth around its axis, and consequently, the position of animals on the surface of the planet relative to space objects.

Comparative Evaluation of Calibrated and Non-calibrated Infrared Thermometer Versus Calibrated Digital Thermometer in Healthy Volunteers and Febrile Patients in a Tertiary Care Center in Central India.

Body temperature is a crucial indicator in assessing human physiological activity and health, particularly in pediatric and critically ill patients. This study aimed to compare temperature recordings obtained from digital calibrated thermometers with calibrated infrared thermometers and non-calibrated infrared thermometers against calibrated ones. An observational prospective study was conducted at AIIMS Bhopal, involving volunteers and febrile patients who consented to participate. Approval was obtained from the Institutional Human Ethics Committee, and 200 participants meeting inclusion/exclusion criteria were included. Data were collected and analyzed using Microsoft Excel. Mean and variance values were computed for both volunteer and febrile patient groups. The P values in both groups were less than 0.05, indicating a significant difference between non-calibrated handheld infrared thermometers (T1), calibrated digital thermometers (T2), and their individual comparison with calibrated infrared thermometers (T3). Variance was higher in non-calibrated infrared thermometers (T1) compared to calibrated ones (T2) in both healthy volunteers and febrile patients. Pearson's correlation coefficient analysis within the febrile patient group demonstrated a robust positive correlation among all three thermometers compared to the healthy volunteers group. The study highlights variations in temperature readings when using different thermometers, irrespective of whether the assessment is conducted on healthy volunteers or febrile patients. Notably, the strength of association is lower in healthy volunteers than in febrile patients, suggesting that the interchangeability of thermometers may be more reliable and sufficient when assessing individuals with fever. These findings underscore the importance of careful consideration and validation of thermometer choices, especially in clinical settings where accurate temperature measurement is critical.