Variation In Body Temperature Research Articles

Feeding Behavior Modifies the Circadian Variation in RR and QT intervals by Distinct Mechanisms in Mice.

Rhythmic feeding behavior is critical for regulating phase and amplitude in the »24-hour variation of heart rate (RR intervals), ventricular repolarization (QT intervals), and core body temperature in mice. We hypothesized changes in cardiac electrophysiology associated with feeding behavior were secondary to changes in core body temperature. Telemetry was used to record electrocardiograms and core body temperature in mice during ad libitum-fed conditions and after inverting normal feeding behavior by restricting food access to the light cycle. Light cycle-restricted feeding modified the phase and amplitude of 24-hour rhythms in RR and QT intervals, and core body temperature to realign with the new feeding time. Changes in core body temperature alone could not account for changes in phase and amplitude in the »24-hour variation of the RR intervals. Heart rate variability analysis and inhibiting β-adrenergic and muscarinic receptors suggested that changes in the phase and amplitude of 24-hour rhythms in RR intervals were secondary to changes in autonomic signaling. In contrast, changes in QT intervals closely mirrored changes in core body temperature. Studies at thermoneutrality confirmed that the daily variation in QT interval, but not RR interval, primarily reflected daily changes in core body temperature (even in ad libitum-fed conditions). Correcting the QT interval for differences in core body temperature helped unmask QT interval prolongation after starting light cycle-restricted feeding and in a mouse model of long QT syndrome. We conclude feeding behavior alters autonomic signaling and core body temperature to regulate phase and amplitude in RR and QT intervals, respectively.

Drowsiness Detection using Python

The Driver Drowsiness Detection System is a sophisticated safety solution designed to mitigate the risks associated with driver fatigue and drowsiness while operating a vehicle. This project aims to develop an intelligent system capable of monitoring driver behavior and physiological signals in real-time, detecting signs of drowsiness, and issuing timely alerts to prevent accidents. The system utilizes a combination of hardware sensors, including cameras, infrared sensors, EEG sensors, and heart rate monitors, to capture and analyze various indicators of driver drowsiness, such as facial expressions, eye movements, head gestures, body temperature, brainwave patterns, and heart rate variability.

Variability in the summer movements, habitat use and thermal biology of two fish species in a temperate river

The ability of fish to cope with warm water temperatures in summer depends on factors including their thermal traits and the ability of individuals to access cool-water refugia. Knowledge is highly limited on the in situ responses of many fishes to elevated summer temperatures, including whether they express behavioural thermoregulation. The responses of two riverine species to summer water temperatures were tested here using the movement metrics, spatial habitat use and body temperatures of individual European barbel Barbus barbus (‘barbel’) and common bream Abramis brama (‘bream’) versus river temperatures. Acoustic biotelemetry was applied in the lower River Severn basin, western Britain, in summer 2021 (barbel) and 2022 (bream), where individuals could move across > 150 km of river, including a tributary of cooler water. Across all individuals, bream occupied 37 km of river length (mainstem only), with low inter-individual variability in their spatial habitat use, movements and body temperatures. In contrast, barbel occupied 62 km of river (main river/tributary), with relatively high inter-individual variability in spatial habitat use, movements and body temperatures, with higher variation in body temperatures as river temperatures increased (maximum mean daily temperature difference between individuals on the same day: 4.2 °C). Although warmer individuals generally moved more, their activity was greatest at relatively low temperatures and higher flows, and neither species revealed any evidence of behavioural thermoregulation during elevated temperatures. Enabling phenotypically diverse fish populations to express their natural behaviours and thermal preferences in summer water temperatures thus requires maintaining their free-ranging in thermally heterogenous habitats.

Sex-specific heterothermy patterns in wintering captive Microcebus murinus do not translate into differences in energy balance

The physiological mechanisms of responses to stressors are at the core of ecophysiological studies that examine the limits of an organism's flexibility. Interindividual variability in these physiological responses can be particularly important and lead to differences in the stress response among population groups, which can affect population dynamics. Some observations of intersexual differences in heterothermy raise the question of whether there is a difference in energy management between the sexes. In this study, we assessed male and female differences in mouse lemurs (Microcebus murinus), a highly seasonal malagasy primate, by measuring their physiological flexibility in response to caloric restriction and examining the subsequent impact on reproductive success. Using complementary methods aiming to describe large-scale and daily variations in body temperature throughout a 6-month winter-like short-day (SD) period, we monitored 12 males and 12 females, applying chronic 40% caloric restriction (CR) to 6 individuals in each group. We found variations in Tb modulation throughout the SD period and in response to caloric treatment that depended on sex, as females, regardless of food restriction, and CR males, only, entered deep torpor. The use of deeper torpor, however, did not translate into a lower loss of body mass in females and did not affect reproductive success. Captive conditions may have buffered the depth of torpor and minimised the positive effects of torpor on energy savings. However, the significant sex differences in heterothermy we observed may point to physiological benefits other than preservation of energy reserves.

Evolution of avian heat tolerance: The role of atmospheric humidity.

The role of atmospheric humidity in the evolution of endotherms' thermoregulatory performance remains largely unexplored, despite the fact that elevated humidity is known to impede evaporative cooling capacity. Using a phylogenetically informed comparative framework, we tested the hypothesis that pronounced hyperthermia tolerance among birds occupying humid lowlands evolved to reduce the impact of humidity-impeded scope for evaporative heat dissipation by comparing heat tolerance limits (HTLs; maximum tolerable air temperature), maximum body temperatures (Tbmax), and associated thermoregulatory variables in humid (19.2 g H2O m-3) versus dry (1.1 g H2O m-3) air among 30 species from three climatically distinct sites (arid, mesic montane, and humid lowland). Humidity-associated decreases in evaporative water loss and resting metabolic rate were 27%-38% and 21%-27%, respectively, and did not differ significantly between sites. Decreases in HTLs were significantly larger among arid-zone (mean ± SD = 3.13 ± 1.12°C) and montane species (2.44 ± 1.0°C) compared to lowland species (1.23 ± 1.34°C), with more pronounced hyperthermia among lowland (Tbmax = 46.26 ± 0.48°C) and montane birds (Tbmax = 46.19 ± 0.92°C) compared to arid-zone species (45.23 ± 0.24°C). Our findings reveal a functional link between facultative hyperthermia and humidity-related constraints on evaporative cooling, providing novel insights into how hygric and thermal environments interact to constrain avian performance during hot weather. Moreover, the macrophysiological patterns we report provide further support for the concept of a continuum from thermal specialization to thermal generalization among endotherms, with adaptive variation in body temperature correlated with prevailing climatic conditions.

Mother–offspring conflict and body temperature regulation during gestation and lactation in a wild primate

Abstract The physiological performance of a mother during reproduction represents a trade‐off between continued investment in her current offspring, and the mother's own survival and ability to invest in future offspring. Here, we used core body temperature (Tb) patterns to examine the degree to which maternal body temperatures support the infant during periods of gestation and lactation. We implanted 30 wild vervet monkeys (Chlorocebus pygerythrus) with miniature data loggers to obtain continuous measurements of core Tb during periods of typical (i.e. non‐drought periods) and limited (i.e. drought period) resource availability. We tracked maternal Tb profiles across the gestation and lactation periods, associated with 23 births, and compared those with Tb profiles of non‐reproductive females. This allowed us to examine the flexibility in maternal body temperatures and test whether limited resource availability shifts priority away from offspring investment and towards self‐maintenance. Vervet monkeys demonstrated the predicted pattern of gestational hypothermia and improved homeothermy in the gestation period during typical conditions, consistent with the maintenance of a thermal gradient to facilitate heat loss from the foetus. During periods of limited resource availability (i.e. drought), mothers were less homeothermic and more hyperthermic during the gestation period. Vervet monkeys showed no evidence of lactational hyperthermia during typical conditions. During the drought, lactating mothers demonstrated hyperthermia and increased variability in body temperature, consistent with the increased metabolic demands and water requirements for milk production required to support growing infants. Although a mother's degree of homeothermy during gestation and lactation was unrelated to her infant's chance of survival to weaning, mothers did show flexibility in the degree to which they prioritized the maintenance of a thermal environment that supports their infant's development. Together, our findings demonstrate that flexibility in a mother's investment in thermoregulation during gestation and lactation may reflect a bet‐hedging trade‐off between self‐maintenance and offspring investment. Read the free Plain Language Summary for this article on the Journal blog.

Temperature impacts SARS-CoV-2 spike fusogenicity and evolution.

When it infects humans, SARS-CoV-2 is exposed to different temperatures (e.g., replication site and fever). Temperature has been shown to strongly impact SARS-CoV-2 replication, but how it affects the activity and evolution of the spike protein remains poorly understood. Here, we first show that high temperatures increase the SARS-CoV-2 spike fusogenicity. Then, we demonstrate that the evolution of the spike activity and variants depends on temperature. Finally, we show that the functional effect of specific spike mutations is temperature-dependent. Overall, our results suggest that temperature may be a factor influencing the activity and adaptation of the SARS-CoV-2 spike in vivo, which will help understanding viral tropism, pathogenesis, and evolution.

Best of both worlds: Acclimation to fluctuating environments confers advantages and minimizes costs of constant environments

Abstract Thermal acclimation is often considered critical in organismal responses to novel thermal conditions. Our understanding of the physiological implications of acclimation is largely derived from lab studies that either manipulate daytime basking availability or use of constant thermal regimes. In contrast, the importance of the nocturnal thermal environment (e.g. the extent of thermal respite) is often overlooked yet could play a vital role in thermal acclimation in the wild. To fill this gap, we acclimated lizards (Amphibolurus muricatus) under three thermal regimes (Hot Constant, Cold Constant and Alternating) and compared their physiological responses (Metabolic Rate, Sprint Speed, Thermal Preferences and Thermal Limits). We found that animals maintained constantly at hot temperatures (preferred temperature, 35°C) gained sprint performance increases and exhibited shifts in thermal optima not seen in those maintained constantly at cold temperatures (20°C), yet suffered costs to growth (in smaller animals) and maintenance (mass loss in larger animals). Animals maintained at alternating temperatures (12 h 20°C; 12 h 35°C) had performance benefits similar to animals in the hot treatment, without experiencing reductions in juvenile growth and adult mass. Animals acclimated under hot temperatures showed a significant lower preferred and voluntary maximum temperatures compared to animals acclimated under a cold temperature regime. We found no impact of acclimation treatment on behavioural thermal limits or standard metabolic rate. Overall, we show that alternating between access to preferred temperatures and having periods of energetic rest confer the greatest benefits for our animals. These results highlight the importance of natural body temperature variation for enhancing overall ectotherm performance and physiology, and the costs of novel thermal environments that fail to provide this variation. Read the free Plain Language Summary for this article on the Journal blog.

Geographic variation of advertisement calls in the terrestrial frog Eleutherodactylus nitidus (Anura: Eleutherodactylidae) in southern Mexico

ABSTRACT Geographic variation in acoustic characteristics of anuran advertisement calls could be an important indicator of species divergence due to its importance for species recognition. In this study, we evaluated the hypotheses of morphological by-product, local adaptation, and genetic drift to explain the geographic variation of the calls of the frog Eleutherodactylus nitidus. We compared six acoustic variables using ANOVA and linear discriminant analyses, as well as inter- and intra-population and intra-individual variation estimates to understand E. nitidus call variation. Recorded calls were corrected for temperature and body size to rule out the influence of these factors on call variation. The advertisement call of E. nitidus is a short whistle with an oscillating amplitude modulation that forms pulses. In total, we analysed 1676 advertisement calls from 66 individuals. We find that call duration, call amplitude, dominant frequency, pulses per call and highest pulse differ between populations, and such differences were independent of body size and temperature variation, ruling out the morphological by-product and local adaptation hypotheses. Additionally, the linear discriminant analysis indicates that geographic call variation depends principally on call amplitude. We suggest that the geographic distance between populations of E. nitidus yields genetic differences that account for differences in advertisement calls.

Environmental enrichments and data-driven welfare indicators for sheltered dogs using telemetric physiological measures and signal processing.

Shelters are stressful environments for domestic dogs which are known to negatively impact their welfare. The introduction of outside stimuli for dogs in this environment can improve their welfare and life conditions. However, our current understanding of the influence of different stimuli on shelter dogs' welfare is limited and the data is still insufficient to draw conclusions. In this study, we collected 28days (four weeks) of telemetry data from eight male dogs housed in an Italian shelter for a long period of time. During this period, three types of enrichment were introduced into the dogs' pens for one week each: entertaining objects, intraspecific, and interspecific social enrichment, by means of the presence of female conspecifics and the presence of a human. To quantify their impact, we introduce novel metrics as indicators of sheltered dogs' welfare based on telemetry data: the variation of heart rate, muscle activity, and body temperature from an average baseline day, quality of sleep, and the regularity for cyclicity of the aforementioned parameters, based on the day-night cycle. Using these metrics, we show that while all three stimuli statistically improve the dogs' welfare, the variance between individual dogs is large. Moreover, our findings indicate that the presence of female conspecific is the best stimulus among the three explored options which improves both the quality of sleep and the parameters' cyclicity. Our results are consistent with previous research findings while providing novel data-driven welfare indicators that promote objectivity. Thus, this research provides some useful guidelines for managing shelters and improving dogs' welfare.

Evaluation of Non-Contact Device to Measure Body Temperature in Sheep.

Non-contact devices have been used in the measurement of body temperature in livestock production as a tool for testing disease in different species. However, there are few studies about the variation and correlations in body temperature between rectal temperature (RT) and non-contact devices such as non-contact infrared thermometers (NCIT) and thermal imaging/infrared thermography (IRT). The objective of this work was to evaluate the accuracy of non-contact devices to measure the body temperature in sheep, considering six body regions and the possibility of implementing these systems in herd management. The experiment was carried out at the experimental farm of the Catholic University of Valencia, located in the municipality of Massanassa in July of 2021, with 72 dry manchega ewes, and we compared the rectal temperature with two types of non-contact infrared devices for the assessment of body temperature in healthy sheep. Except for the temperature taken by NCIT at the muzzle, the correlation between RT vs. NCIT or IRT showed a low significance or was difficult to use for practical flock management purposes. In addition, the variability between devices was high, which implies that measurements should be interpreted with caution in warm climates and open pens, such as most sheep farms in the Spanish Mediterranean area. The use of infrared cameras devices to assess body temperature may have a promising future, but in order to be widely applied as a routine management method on farms, the system needs to become cheaper, simpler in terms of measurements and quicker in terms of analyzing results.

Longitudinal genomic analyses of automatically-recorded vaginal temperature in lactating sows under heat stress conditions based on random regression models

BackgroundAutomatic and continuous recording of vaginal temperature (TV) using wearable sensors causes minimal disruptions to animal behavior and can generate data that enable the evaluation of temporal body temperature variation under heat stress (HS) conditions. However, the genetic basis of TV in lactating sows from a longitudinal perspective is still unknown. The objectives of this study were to define statistical models and estimate genetic parameters for TV in lactating sows using random regression models, and identify genomic regions and candidate genes associated with HS indicators derived from automatically-recorded TV.ResultsHeritability estimates for TV ranged from 0.14 to 0.20 over time (throughout the day and measurement period) and from 0.09 to 0.18 along environmental gradients (EG, − 3.5 to 2.2, which correspond to dew point values from 14.87 to 28.19 ˚C). Repeatability estimates of TV over time and along EG ranged from 0.57 to 0.66 and from 0.54 to 0.77, respectively. TV measured from 12h00 to 16h00 had moderately high estimates of heritability (0.20) and repeatability (0.64), indicating that this period might be the most suitable for recording TV for genetic selection purposes. Significant genotype-by-environment interactions (GxE) were observed and the moderately high estimates of genetic correlations between pairs of extreme EG indicate potential re-ranking of selection candidates across EG. Two important genomic regions on chromosomes 10 (59.370–59.998 Mb) and16 (21.548–21.966 Mb) were identified. These regions harbor the genes CDC123, CAMK1d, SEC61A2, and NUDT5 that are associated with immunity, protein transport, and energy metabolism. Across the four time-periods, respectively 12, 13, 16, and 10 associated genomic regions across 14 chromosomes were identified for TV. For the three EG classes, respectively 18, 15, and 14 associated genomic windows were identified for TV, respectively. Each time-period and EG class had uniquely enriched genes with identified specific biological functions, including regulation of the nervous system, metabolism and hormone production.ConclusionsTV is a heritable trait with substantial additive genetic variation and represents a promising indicator trait to select pigs for improved heat tolerance. Moderate GxE for TV exist, indicating potential re-ranking of selection candidates across EG. TV is a highly polygenic trait regulated by a complex interplay of physiological, cellular and behavioral mechanisms.

Tau Secretion is Driven by Circadian Variations of Body Temperature during the Sleep/Wake Cycle: Implications for Tau Spreading in Alzheimer's Disease

Propagation of hyperphosphorylated and aggregated tau protein is a hallmark of Alzheimer’s disease (AD). Previously, we demonstrated that tau phosphorylation is inversely correlated with body temperature (BT) variations during the sleep/wake cycle. Tau is hyperphosphorylated during sleep (when BT is lower), compared to wakefulness (when BT is higher). Interestingly, it has been shown that tau in ISF and CSF is increased during wakefulness, suggesting increased secretion. We thus hypothesized that tau secretion might be regulated by BT during the sleep/wake cycle.

Relationship Between Ovulation and Body Temperature in the Mare: A Preliminary Study

In the equine industry, monitoring of the reproduction cycle is key to be able to produce one foal per mare and per year. Ovulation detection is difficult partly due to the variability of the estrus length. Currently, the most reliable method for ovulation detection is transrectal ultrasonography. This technique, however, implies handling of the mare as well as veterinary costs. The aim of this experimentation is to study body temperature variations around ovulation. Nine reproduction cycles were monitored around ovulation. Transrectal ultrasonographies were performed each day as well as blood sampling to dose estradiol-17β and progesterone to confirm ultrasonographic results. Body temperature was automatically recorded every 10 minutes using an identification chip equipped with a temperature sensor implanted in the mares’ neckline. Data were analyzed using linear mixed models. Daily body temperature pattern did not vary between the phases of the reproductive cycle (follicular, ovulatory and luteal). Temperature differences between phases, however, were identified and appeared hourly-specific. There was an increase of temperature at ovulation compared to the end of the follicular phase ranging from 0.51°C ± 0.21°C to 0.92°C ± 0.26°C and occurring between 04:30 and 08:00. Moreover, a significant increase of body temperature was measured during the first days of luteal phase, ranging from 0.29°C ± 0.17°C to 0.60°C ± 0.16°C, between 10:30 and 16:00. Body temperature varied around ovulation and it might be a promising tool for mare reproduction monitoring. A more complete study, however, focusing on the whole cycle is required.

Diurnal temperature variation and the implications for diagnosis and infectious disease screening: a population-based study.

Fevers have been used as a marker of disease for hundreds of years and are frequently used for disease screening. However, body temperature varies over the course of a day and across individual characteristics; such variation may limit the detection of febrile episodes complicating the diagnostic process. Our objective was to describe individual variation in diurnal temperature patterns during episodes of febrile activity using millions of recorded temperatures and evaluate the probability of recording a fever by sex and for different age groups. We use timestamped deidentified temperature readings from thermometers across the US to construct illness episodes where continuous periods of activity in a single user included a febrile reading. We model the mean temperature recorded and probability of registering a fever across the course of a day using sinusoidal regression models while accounting for user age and sex. We then estimate the probability of recording a fever by time of day for children, working-age adults, and older adults. We find wide variation in body temperatures over the course of a day and across individual characteristics. Thediurnal temperature pattern differed between men and women, and average temperatures declined forolder age groups. The likelihood of detecting a fever varied widely by the time of day and by an individual's age or sex. Time of day and demographics should be considered when using body temperatures for diagnostic or screening purposes. Our results demonstrate the importance of follow-up thermometry readings if infectious diseases are suspected.

A deep learning-based detection method for pig body temperature using infrared thermography

Body temperature is one of the important indicators that reflect the health of pigs. The traditional rectal temperature measurement is inconvenient and time-consuming, and also easy to cause stress responses to pigs. Infrared Thermography (ITG) was supposed to have potentials to realize non-invasive and rapid temperature detection for pigs in intensive pig farming. In this paper, an automatic temperature detection method base on ITG was developed. First, temperatures on six regions on pig body surface (i.e., forehead (FH), eyes, nose, ear root (ET), back and anus) were measured by ITG for the region of interest (ROI) selection; Then, an improved model of YOLOv5s-BiFPN was developed for automatic ROI detection and temperature extraction. A dataset with 2797 images that collected from sixteen pigs for 30 days was used for model development. It was shown that temperatures on FH and ET were supposed to be the ROI for ITG temperature detection and because of their strong correlations with the rectal temperature among the six parts on pig body surface. Also, the maximum temperature (MaxT) on FH and ET could reflect pig’s body temperature variations the best. The proposed model of YOLOv5s-BiFPN achieved optimal performances (e.g., the mAP was 96.36%, outperformance was 20 MB, target detection speed was up to 100 frame/s), and the mAPs were increased by 4.85%, 4.38%, 1.60%, 1.56%, 31.52%, and 22.42% compared with models of CenterNet, Faster R-CNN, YOLOv4, YOLOv5s, Nanodet and YOLOv5n, respectively. Therefore, it is a feasible way for pig body temperature automatic detection and facilitates early staged disease warning and environmental control.

The formalization of the concept of Functions Defined by More than One Sentence in Mathematics textbooks

The general objective of this work is to analyze how the Mathematics textbooks, made available by the National Textbook Program (PNLD) 2021 — Object 2, approach the formalization of the concept of Functions Defined by More than One Sentence. Thus, an exploratory research with a qualitative approach was carried out. The theoretical notes are based on theorists and researchers who deal with the researched themes. The study revealed that textbooks present these functions in a contextualized way, exploring problem situations that enable students to recognize regularities in real phenomena and generalize observed laws or patterns. The examples used include topics such as income tax, production cost and body temperature variation, demonstrating the practical application of these functions. It was also identified that the formalization of the concept of these functions is done intuitively, without explicit mathematical rigor.

Not so fast: Paradoxically increased variability in the glucose tolerance test due to food withdrawal in continuous glucose-monitored mice

ObjectiveThis study was performed to determine the effect of fasting on reproducibility of the glucose tolerance test. Due to individual variation in animal feeding behaviors, fasting animals prior to metabolic and behavioral experiments is widely held to reduce inter-subject variation in glucose and metabolic parameters of preclinical rodent models. Reducing variability is especially important for studies where initial metabolite levels can influence the magnitude of experimental interventions, but fasting also imposes stress that may distort the variables of interest. One such intervention is the glucose tolerance test (GTT) which measures the maximum response and recovery following a bolus of exogenous glucose. We sought to investigate how fasting affects the response of individual mice to a GTT. MethodsUsing simultaneous continuous glucose monitoring (CGM) and indirect calorimetry, we quantified blood glucose, physical activity, body temperature, metabolic rates, and food consumption levels on a minute-to-minute basis in adult male mice for 4 weeks. We tested the effects of a 4-h or 18-h fast on the GTT to examine the effect of food withdrawal in light or dark photoperiods. Studies were also performed with 4-h fasting in additional mice without implanted CGM probes. ResultsContrary to our expectations, a 4-h fast during the light photoperiod promotes a paradoxical increase in inter-animal variation in metabolic rate, physical activity, body temperature, glycemia, and glucose tolerance. This hyperglycemic and hyper-metabolic phenotype promotes increased corticosterone levels and is consistent with a behavioral stress response to food deprivation, even in well-fed mice. We find that mice undergoing an 18-h fast entered torpor, a hibernation-like state. In addition to low body temperature and metabolic rate, torpor is also associated with glucose levels 56 mg/dl lower than those seen in mice with ad libitum access to food. Moreover, the time spent in torpor affects the response to a GTT. ConclusionOur results suggest fasting mice before glucose tolerance testing, and perhaps other experiments, can have the opposite of the intended effect where fasting can increase, rather than decrease, experimental variability.

Enhancing Face Recognition Performance with Multispectral Imaging and Machine Learning: Comparison from Sift and Sift-Freak Feature Extraction

The development of modern societies faces many security and identification challenges. To meet this expectation, computer vision offers biometric solutions. Much research in recent years has focused on face recognition. Traditional facial recognition that uses color images has had many shortcomings, such as variation in illumination, smoke, rain, disguise, face concealment, makeup, etc. Light-insensitive infrared (IR) imaging is presented as an alternative to facial recognition in the visible to overcome the shortcomings of uncontrolled environments. However, IR also has weaknesses, such as facial occlusion by glasses, variation in body temperature, perfusion, etc. This paper proposes a new facial recognition architecture that uses several classification algorithms, detectors, and feature descriptors in multispectral imaging. A combination of SIFT and FREAK, feature extraction tools, was associated with classification algorithms such as SVM, logistic regression, and Random forest to conduct this study. Several experiments were made to evaluate the performance of the proposed recognition system. The validation process of the proposed multispectral face recognition method involved several important steps. First, experiments were carried out on visible and infrared spectrum images to measure the recognition system's performance. These experiments made it possible to compare the recognition performances between these two types of images. Then, fuse visible and infrared images were used to assess multispectral facial recognition. The goal was to maximize each spectrum's advantages while minimizing their disadvantages. Metrics were evaluated to measure the accuracy of the multispectral face recognition method. The performances were compared with classical facial recognition methods, such as facial recognition based on the visible spectrum or infrared imagery alone. The results showed that the proposed multispectral facial recognition method performed better than traditional methods, reaching a facial recognition score ranging from 76% to 95% in the IRIS database.

Increase of Body Temperature Immediately After Ovulation in Mares.

To successfully inseminate mares, precise detection of ovulation time is crucial, especially when using frozen-thawed semen. Monitoring body temperature, as has been described in women, could be a noninvasive way to detect ovulation. The objective of this study was to investigate the relationship between the time of ovulation and the variation of body temperature in mares based on automatic continuous measurements during estrus. The experimental group included 21mares for 70analyzed estrous cycles. When the mares showed estrous behavior, they were administered intramuscular deslorelin acetate (2.25mg) in the evening. At the same time, monitoring of body temperature using a sensor device fixed at the left lateral thorax was started and continued for over 60hours. In 2-hour intervals, transrectal ultrasonography was performed to detect ovulation. Estimated body temperature in the 6 hours following ovulation detection was on average 0.06°C +/- 0.05°C (mean+/-SD) significantly higher when compared with body temperature at the same time on the preceding day (P=.01). In addition, a significant effect of PGF2α administration for estrus induction on the body temperature was found, being significantly higher until 6hours before ovulation compared to that of uninduced cycles (P=.005). In conclusion, changes in body temperature during estrus in mares were related to ovulation. The increase in body temperature immediately after ovulation might be used in the future to establish automatized and noninvasive systems to detect ovulation. However, the identified temperature rise is relatively small on average and hardly identifiable in the individual mares.