BODY HEAT STORAGE, METABOLISM AND RESPIRATION OF COWS ABRUPTLY EXPOSED AND ACCLIMATIZED TO COLD AND 18 °C ENVIRONMENTS

1984 ◽  
Vol 64 (3) ◽  
pp. 641-653 ◽  
Author(s):  
J. A. McLEAN ◽  
W. T. WHITMORE ◽  
B. A. YOUNG ◽  
R. WEINGARDT
Keyword(s):  
Initial Phase ◽  
Heat Storage ◽  
The Body ◽  
Second Phase ◽  
Mean Body Temperature ◽  
Cyclic Patterns ◽  
Cyclic Temperature ◽  
Two Phases ◽  
Body Heat ◽  
Effective Buffer

Six cows were alternated between cold (−30 to 0 °C) and 18 °C environments. Rectal (Tr), mean skin (Ts) and mean body (Tb = 0.86 Tr + 0.14 Ts) temperatures, respiration rate (RR) and metabolism per unit body size (M) were measured on first exposure and after acclimatization to each environment. Cows acclimatized to the cold had the same Tr as when acclimatized to 18 °C, but Ts and RR were lower and M was higher in the cold than in the 18 °C environment. Acclimatization appeared to occur in two phases. In the initial phase, lasting less than a day, new 24-h cyclic patterns (greater in the cold than in 18 °C) were established in body temperatures, respiration and metabolism. In the second phase which took longer than 2 days new levels were established in these parameters. The change in heat stored in the body between the two environments was not as great as previously found in an environment with a relatively small but cyclic temperature variation. It is suggested that changes in body heat storage are associated with cyclic or sudden changes in the environment, when it can act as an effective buffer against thermal stress. Key words: Cattle, mean body temperature, body heat storage, acclimatization

Heat storage regulation in exercise during thermal transients

1976 ◽  
Vol 40 (3) ◽  
pp. 384-392 ◽  
Author(s):  
P. Chappuis ◽  
P. Pittet ◽  
E. Jequier
Keyword(s):  
Heat Storage ◽  
Mean Value ◽  
The Body ◽  
Mean Body Temperature ◽  
Ambient Temperatures ◽  
Thermal Transients ◽  
Thermoregulatory System ◽  
Body Heat ◽  
Rest And Exercise

Rate of heat storage (S) was measured by using direct and indirect calorimetry simultaneously in 11 subjects during rest and exercise at three ambient temperatures (Ta of 20, 25, and 30 degrees C), and at two work intensities (40 and 90 W). At rest, the mean value of S was -64.9 W at 20 degrees C, -26.1 W at 25 degrees C, and +9.9 W at 30 degrees C. After 50 min of exercise at 40 or 90 W, S tended toward zero at the three ambient temperatures. This indicates that thermal equilibrium was reached. In addition, at the end of the exercise periods total heat losses (R + C + E) measured at a Ta of 20, 25, and 30 degrees C were similar, i.e., independent of Ta. During the thermal transients and the steady state of exercise, the calorimetric method allows immediate measurement of S to be made, since all the physical terms of the body heat balance equation are determined. The changes in mean body temperature (delta Tb) measured by thermometry showed a delay of 5–10 min when compared with delta Tb measured by calorimetry. Thus, determination of delta Tb by thermometry is not directly applicable during thermal transients, unless the observed delay is taken into account. Our results also support the concept that Tb may be the regulated variable of the thermoregulatory system, since we obtained a very significant and uniform correlation between Esk and delta Tb at the three Ta and the two work intensities which were studied.

Body heat storage in steers (Bos taurus) in fluctuating thermal environments

1983 ◽  
Vol 100 (2) ◽  
pp. 315-322 ◽  
Author(s):  
J. A. McLean ◽  
D. P. Stombaugh ◽  
A. J. Downie ◽  
C. A. Glasbey
Keyword(s):  
Body Temperature ◽  
Environmental Temperature ◽  
Heat Storage ◽  
Bos Taurus ◽  
Weighting Factor ◽  
The Body ◽  
Environmental Fluctuation ◽  
Mean Body Temperature ◽  
Thermal Environments ◽  
Body Heat

SUMMARYHeat stored in the body of cattle subjected to a daily 10 CC range of environmental temperature was measured by calorimetry and thermometry. The daily range of bodycore temperature of the animals was of the order of 0·5 °C but mean skin temperature cycled with a range of approximately 6 °C. Calorimetric estimates of changes in mean body temperature showed good agreement with thermometric estimates when core and mean body temperature changes were weighted in the ratio a: (1 – α) where α was found to be 0·85. This result is consistent with the findings of another study where cattle were subjected to abrupt changes in environmental temperature, the combined best estimate of a from the two studies being 0·86 ± 0·014 (s.E.). The 10 °C range of daily environmental fluctuation resulted in a daily variation of approximately 1 °C in mean body temperature, which is equivalent to the amount of heat produced by the animals every 40 min. It is suggested that a weighting factor α = 0·86 could be employed, using thermometry only, to estimate fluctuations in body heat storage which are likely to occur in animals subjected to fluctuating environmental conditions in the field.

scholarly journals Equation Córdoba: A Simplified Method for Estimation of Body Fat (ECORE-BF)

2019 ◽  
Vol 16 (22) ◽  
pp. 4529 ◽  
Author(s):  
Molina-Luque ◽  
Romero-Saldaña ◽  
Álvarez-Fernández ◽  
Bennasar-Veny ◽  
Álvarez-López ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Intraclass Correlation Coefficient ◽  
Body Fat ◽  
Intraclass Correlation ◽  
The Body ◽  
Second Phase ◽  
Fat Percentage ◽  
Daily Work ◽  
Two Phases ◽  
New Equation

Background: Many methods for measuring body fat have been developed, but applications in clinical settings are limited. For this reason, researchers have tried to identify different formulas for its estimation but most of are hard to incorporate into daily work due to the variability in population and difficulty of use. The aim of this study was to develop and validate a new equation for the simplified estimation of body fat using the Clínica Universidad de Navarra – Body Adiposity Estimator (CUN-BAE) as a reference. Methods: This research was conducted in two phases. In the first, the new body fat estimation equation was developed. The developed equation was validated in the second phase. Pearson’s linear correlation, raw and adjusted linear regressions, the intraclass correlation coefficient, and Bland–Altman graphs were used. Results: The variables that best adjusted the body fat percentage were age, sex, and the Napierian logarithm of Body Mass Index (LnBMI), forming the Equation Córdoba for Estimation of Body Fat (ECORE-BF) model. In its validation, the model presented correlation values of 0.994, an intraclass correlation coefficient of 0.960, with the Bland–Altman graph indicating means differences of 1.82 with respect to the estimation with the CUN-BAE. Nevertheless, although the aim was to simplify the CUN-BAE, the main limitation of this study is that a gold standard, such as air displacement plethysmography (ADP) or dual-energy X-ray absorptiometry (DXA), was not used. Conclusions: The proposed equation (ECORE-BF) simplified the CUN-BAE and provided a precise method, respecting the principle of parsimony, for the calculation of body fat.

Relationship between body heat content and finger temperature during cold exposure

2001 ◽  
Vol 90 (6) ◽  
pp. 2445-2452 ◽  
Author(s):  
Dragan Brajkovic ◽  
Michel B. Ducharme ◽  
John Frim
Keyword(s):  
Skin Temperature ◽  
Heat Storage ◽  
Heat Content ◽  
The Body ◽  
Finger Temperature ◽  
Finger Dexterity ◽  
The Relationship ◽  
Finger Skin ◽  
Body Heat ◽  
Partitional Calorimetry

The purpose of the present experiment was to examine the relationship between rate of body heat storage (S˙), change in body heat content (ΔHb), extremity temperatures, and finger dexterity. S˙, ΔHb , finger skin temperature (Tfing), toe skin temperature, finger dexterity, and rectal temperature were measured during active torso heating while the subjects sat in a chair and were exposed to −25°C air. S˙ and ΔHb were measured using partitional calorimetry, rather than thermometry, which was used in the majority of previous studies. Eight men were exposed to four conditions in which the clothing covering the body or the level of torso heating was modified. After 3 h, Tfing was 34.9 ± 0.4, 31.2 ± 1.2, 18.3 ± 3.1, and 12.1 ± 0.5°C for the four conditions, whereas finger dexterity decreased by 0, 0, 26, and 39%, respectively. In contrast to some past studies, extremity comfort can be maintained, despite S˙ that is slightly negative. This study also found a direct linear relationship between ΔHb and Tfing and toe skin temperature at a negative ΔHb. In addition, ΔHb was a better indicator of the relative changes in extremity temperatures and finger dexterity over time than S˙.

Metabolic, thermoregulatory, and perceptual responses during exercise after lower vs. whole body precooling

2003 ◽  
Vol 94 (3) ◽  
pp. 1039-1044 ◽  
Author(s):  
Andrea T. White ◽  
Scott L. Davis ◽  
Thad E. Wilson
Keyword(s):  
Heat Storage ◽  
Thermal Sensation ◽  
Submaximal Exercise ◽  
Whole Body ◽  
Lower Body ◽  
Mean Body Temperature ◽  
Thermal Discomfort ◽  
Healthy Men ◽  
Metabolic Heat ◽  
Body Heat

The purpose of this investigation was to compare the thermoregulatory, metabolic, and perceptual effects of lower body (LBI) and whole body (WBI) immersion precooling techniques during submaximal exercise. Eleven healthy men completed two 30-min cycling bouts at 60% of maximal O2uptake preceded by immersion to the suprailiac crest (LBI) or clavicle (WBI) in 20°C water. WBI produced significantly lower rectal temperature (Tre) during minutes 24–30 of immersion and lower Tre, mean skin temperature, and mean body temperature for the first 24, 14, and 16 min of exercise, respectively. Body heat storage rates differed significantly for LBI and WBI during immersion and exercise, although no net differences were observed between conditions. For WBI, metabolic heat production and heart rate were significantly higher during immersion but not during exercise. Thermal sensation was significantly lower (felt colder) and thermal discomfort was significantly higher (less comfortable) for WBI during immersion and exercise. In conclusion, WBI and LBI attenuated Tre increases during submaximal exercise and produced similar net heat storage over the protocol. LBI minimized metabolic increases and negative perceptual effects associated with WBI.

The Roman Road-Station at Thenadassa (Ain Wif)

1982 ◽  
Vol 13 ◽  
pp. 73-80 ◽  
Author(s):  
D. J. Mattingly
Keyword(s):  
Initial Phase ◽  
Indigenous Population ◽  
Second Century ◽  
Third Century ◽  
Second Phase ◽  
The Third ◽  
Military Presence ◽  
Two Phases ◽  
The Military ◽  
New Evidence

AbstractA reappraisal of the Roman period ruins at Ain Wif has been made following the identification there of traces of defensive walls. These walls are interpreted as being the robbed-out remains of a Roman fortlet and possibly also a tort on the same site. Two phases of military occupation were also evident in modern drain trenches being cut across the site and are attested epigraphically for the military bath-house by the spring. Ceramic evidence from the site suggests that the initial phase lies within the second century, whilst the Severan occupation, known from an inscription to begin early in the third century, represents a second phase. The previous view of the site as an undefended road-station, with a military presence only under the Severan emperors is no longer tenable. Moreover, the new evidence indicates that there was some measure of military organisation in the hinterland of the Emporia prior to the accession of Septimius Severus at the very end of the second century AD. The importance of the site also lies in its large civilian and indigenous population who continued to occupy the site long after the military had departed.

scholarly journals Magnetic relaxation and the Taylor conjecture

2015 ◽  
Vol 81 (6) ◽  
Author(s):  
H. K. Moffatt
Keyword(s):  
Magnetic Field ◽  
Initial Phase ◽  
Magnetic Relaxation ◽  
Magnetic Energy ◽  
Magnetic Pressure ◽  
Second Phase ◽  
One Dimensional ◽  
Induction Equation ◽  
Two Phases ◽  
The Magnetic Field

A one-dimensional model of magnetic relaxation in a pressureless low-resistivity plasma is considered. The initial two-component magnetic field $\boldsymbol{b}(\boldsymbol{x},t)$ is strongly helical, with non-uniform helicity density. The magnetic pressure gradient drives a velocity field that is dissipated by viscosity. Relaxation occurs in two phases. The first is a rapid initial phase in which the magnetic energy drops sharply and the magnetic pressure becomes approximately uniform; the helicity density is redistributed during this phase but remains non-uniform, and although the total helicity remains relatively constant, a Taylor state is not established. The second phase is one of slow diffusion, in which the velocity is weak, though still driven by persistent weak non-uniformity of magnetic pressure; during this phase, magnetic energy and helicity decay slowly and at constant ratio through the combined effects of pressure equalisation and finite resistivity. The density field, initially uniform, develops rapidly (in association with the magnetic field) during the initial phase, and continues to evolve, developing sharp maxima, throughout the diffusive stage. Finally it is proved that, if the resistivity is zero, the spatial mean $\langle (\boldsymbol{b}\boldsymbol{\cdot }\boldsymbol{{\rm\nabla}}\times \boldsymbol{b})/b^{2}\rangle$ is an invariant of the governing one-dimensional induction equation.

Persistence of impaired heat tolerance from artificially induced miliaria rubra

1980 ◽  
Vol 239 (3) ◽  
pp. R226-R232 ◽  
Author(s):  
K. B. Pandolf ◽  
T. B. Griffin ◽  
E. H. Munro ◽  
R. F. Goldman
Keyword(s):  
Heat Stress ◽  
Heat Storage ◽  
Total Body Surface Area ◽  
Control Group ◽  
Heat Illness ◽  
Mean Body Temperature ◽  
Experimental Subjects ◽  
Total Body ◽  
And Control ◽  
Body Heat

Ten volunteers were heat acclimatized to 48.9 degrees C (Ta), 20% rh for 7 days to complete a 100-min walk on a level treadmill (1.56 m x s-1). Subjects were then divided into experimental (n = 6) and control (n = 4) groups. Miliaria rubra (heat rash) was then induced on the experimental subjects by wrapping them for 3 days in polyethylene plastic. All six developed marked miliaria with involvement of 40-70% of the total body surface area. All subjects were reexposed to walking in the heat on the 7th day after unwrapping, by which time rash was clinically indetectable, and again 14 days after unwrapping. On the first test (day 7) only one of the rashed group, and on the second test (day 14) only two could complete the 100-min walk; the control group finished without difficulty on both days. Body heat storage for the rash group was 2.5 times that of the control group on day 7 and 1.5 as great on day 14; measurements of mean body temperature (Tb) on the rash group indicated a much greater heat stress when compared to their own prerash-acclimatized values or those of the control group. These data demonstrate the potential of "healed" miliaria in the etiology of clinical heat illness.

scholarly journals Pressure-induced depolymerization of spindle microtubules. I. Changes in birefringence and spindle length.

1975 ◽  
Vol 65 (3) ◽  
pp. 603-614 ◽  
Author(s):  
E D Salmon
Keyword(s):  
Initial Phase ◽  
Polarized Light ◽  
Meiotic Metaphase ◽  
Second Phase ◽  
Complete Disappearance ◽  
Spindle Microtubule ◽  
Spindle Microtubules ◽  
Optical Pressure ◽  
Two Phases ◽  
Kinetics Of

Changes in birefringence retardation (BR) and length of Chaetopterus meiotic metaphase-arrested spindles produced by increased hydrostatic pressure were observed with polarized-light microscopy using a newly developed optical pressure chamber. Increased pressure produced rapid, reversible decreases in spindle BR and length. Pressures of 3,500 psi or higher at 22 degrees C caused complete disappearance of spindle BR within 3 min. Up to 6,000 psi, the rates of both BR decay and spindle shortening increased progressively with increasing pressure. At 6,000 psi or above, the BR decreased rapidly but there was no evidence of spindle shortening. The general observations are consistent with results of earlier classical experiments on effects of pressure on mitosis, and with experiments that used colchicine or low temperature as microtubule-depolymerizing agents. The kinetics of spindle depolymerization and repolymerization showed two phases: an initial phase of rapid decreases or increase in half-spindle microtubule BR; and a second phase of nearly constant BR during which most of the spindle shortening or growth occurs. BR is assumed to be directly related to the number of microtubules in a spindle cross section. It is hypothesized that microtubules in the spindle have different stabilities depending on the attachment of nonattachment of their ends. This hypothesis is used to explain the two phases of spindle depolymerization and repolymerization as well as several other observations.

Heat balance of ox steers (Bos taurus) in steady-temperature environments

1982 ◽  
Vol 52 (2) ◽  
pp. 324-332 ◽  
Author(s):  
J. A. McLean ◽  
A. J. Downie ◽  
P. R. Watts ◽  
C. A. Glasbey
Keyword(s):  
Heat Storage ◽  
Bos Taurus ◽  
Steady Temperature ◽  
Fixed Temperature ◽  
Mean Body Temperature ◽  
Body Core ◽  
The Difference ◽  
Change In Mean ◽  
Environmental Temperatures ◽  
Body Heat

Work was undertaken to investigate body heat storage in cattle subjected to steady temperature environments. Heat production (M) of and heat losses (H) from two steers were studied by simultaneous direct and indirect calorimetry over periods of up to 11 days. M and H followed similar trends except after feeding and watering. When the animals stood both M and H leveled approximately 20% higher than when they were lying down. Over 24-h periods total M and H agreed within the limits of experimental error. Heat storage of the calorimeter contents (MH) was calculated from the accumulated difference between M and H. Day-night cycles observed in MH were partly due to the heat of warming food and water and of cooling excreta (FF). The difference (TB = MH - FF) represented calorimetrically determined changes in heat storage in the animal's body. Day-night cycles in TB were small (less than 1 degree C range in equivalent change in mean body temperature) but agreed well with observed changes in body core (carotid artery) temperatures. It is concluded that day-night changes in heat storage in fixed-temperature environments are small but measurable by calorimetry and that the methods used are applicable for future studies with cyclic environmental temperatures.

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