Range Of Environmental Temperatures Research Articles

How much wrapping do babies need at night?

In a longitudinal, population based study, overnight temperature recordings were made in the bedrooms of 152 babies aged 3-18 weeks and the insulation provided by their bedclothing was assessed. Outdoor temperatures for the study nights were also available. Parents applied more insulation on colder nights with lower bedroom temperatures than on warmer nights (mean 8.5 tog at 15 degrees C minimum bedroom temperature falling to 4.0 tog at 25 degrees C). For a particular temperature they also applied 2 tog more insulation in winter than in summer. The amounts of bedclothing used in the home were compared with insulation levels predicted to achieve thermo-neutrality over a similar range of environmental temperature from heat balance studies in young infants. They corresponded closely. The average amount of bedclothing chosen for babies in Avon allows them to remain in thermoneutral conditions throughout the night. These values are proposed as broad guidelines for the thermal care of young babies at night.

The effect of endotoxin-induced fever on thermoregulation in the newborn rabbit.

1. Metabolic responses of endotoxin-injected newborn rabbits were measured in a closed circuit calorimeter at a constant environmental temperature within their thermoneutral range. Oxygen consumption and colonic temperatures were then measured over a range of environmental temperatures from 21.0 to 40.0 degrees C and the responses of endotoxin-injected rabbits compared with non-injected litter mates. 2. To measure their preferred thermal environment, endotoxin-injected and non-injected litter mates were allowed to settle on a thermal gradient and their colonic temperatures measured. 3. In a constant environmental temperature of 37 degrees C, rises in oxygen consumption and colonic temperature following endotoxin injection were found to be biphasic. Oxygen consumption rose from 21 ml kg-1 min-1 to a maximum 35 ml kg-1 min-1 and colonic temperature rose from 39.0 to 39.8 degrees C. 4. The maximal rate of oxygen consumption was the same in both injected and non-injected animals, 53 ml kg-1 min-1, being provoked at the same environmental temperature of 24 degrees C. Minimal rates of oxygen consumption were also similar for the two groups but in the injected animals they were achieved at an environmental temperature of 39 degrees C, 2 degrees C higher than for non-injected animals. 5. We conclude that newborn rabbits challenged with a pyrogen have both behavioural and physiological responses. The thermogenic response is consistent with a change in sensitivity to feedback information rather than a simple shift in the central thermoregulatory set point. We find no evidence to support the view that in the febrile response a higher body temperature necessitates an increase in metabolic rate, the so-called Q10 effect.

Insect hydrocarbon chemotaxonomy: Cuticular hydrocarbons of adult and larval epiphysa species blanchard and adult Onymacris unguicularis (HAAG) (tenebrionidae: Coleoptera)

1. 1. The cuticular hydrocarbons of Epiphysa sp. (adult, EPSA; larva, EPSL) and adult Onymacris unguicularis (OU) comprise n-alkanes (EPSA, nC 22- nC 35, 75.4%; EPSL, nC 20- nC 31. 38.3%; OU, nC 20- nC 29, 36.2%), 3-methylalkanes (EPSA, C 25-C 31, 2.5%; EPSL, C 25-C 27, 9.4%; OU, C 25-C 29, 14.9%), internally branched monomethylalkanes (EPSA, C 25-C 40; EPSL, C 25-C 29, 41.1%; OU, C 23-C 31, 24.6%), dimethylalkanes (EPSA, C 25-C 42, 9.6%; EPSL, C 25-C 41, 8.5%; OU, C 23-C 37, 21.3%) and trimethylalkanes (EPSA, C 40-C 43, 0.7%; OU, C 27-C 37, 2.3%). Two tetramethylalkanes (total, 0.5%) were tentatively identified in the mixture of adult Epiphysa sp. 2. 2. Adult Epiphysa sp. has a complex hydrocarbon mixture, while the larval mixture is much simpler. Both instars have dimethylalkanes with central and variable branching (type 3) which have been detected in only one other species of tenebrionid. In the adult, type 3 dimethylalkanes have long chains, while the dimethylalkanes with variable, terminal branching (type 2) have short chains. It is suggested that the biosynthesis of these dimethylalkanes is a way of increasing the number of isomers for a given chain length and thereby increasing the sensitivity of the hydrocarbon mixture to changes in temperature. 3. 3. The melting point of methylalkanes is affected by the number of branches and their position on the alkyl chain and by the number of methylene groups separating the branches. It is suggested that in a complex mixture of methylalkanes such as that of adult Epiphysa sp. or O. unguicularis, conflicting factors affecting melting point average out to give a mixture with overall melting characteristics suited to a given temperature range. This implies that the methylisomer composition of a mixture may not be precisely determined and that the biosynthetic pathways of methylalkanes may be flexible. 4. 4. The complex hydrocarbon mixture of adult Epiphysa sp. suggests that the early members of tribe Adesmiini may have had a wide variety of biosynthetic pathways for hydrocarbon synthesis, including those for type 3 dimethylalkanes, trimetyl- and tetramethylalkanes. 5. 5. The hydrocarbon composition of O. unguicularis and five other species of genus Onymacris, reflects inter-specific similarities as well as divisions and transitions in the genus. It is suggested that the earliest hydrocarbon mixture of the genus was relatively simple, with few hydrocarbons and type 2 dimethylalkanes, a short chain length range and with median chain length (MCL) values above 28.0, and that it was suited to a high and narrow range of environmental temperature. If such a mixture arose from a complex Epiphysa-like mixture, then hydrocarbon composition in the genus first underwent simplification and a raising of MCL values, followed by an increase in complexity and a lowering of MCL values. It is suggested that these changes in composition occurred during the colonization of inland and coastal habitats respectively.

Biophysical Ecology and Heat Exchange in Insects

When used with observations of behavior and physiology of animals in known microclimates, a biophysical approach is a powerful tool for predicting body temperatures of insects. For ectothermic insects, solution of the energy budget equation and use of operative temperature models have been used to determine the range of temperatures which an insect can exhibit in a given environment. Knowledge of body temperature has allowed predictions of when important behaviors arepossible in the field, thereby directly relating biophysical models to fitness parameters of animals. A proper understanding of the physiological mechanism(s) controlling heat exchange is prerequisite to application and interpretation of information obtained using biophysical techniques. For endothermic insects, physiological regulation of heat exchange forces a more complicated analysis. Evaluation of thoracic heat exchange alone (aside from indicating whether insects are regulating Tth) is of little utility for either quantifying total heat exchange, or evaluating thermoregulatory mechanisms without further information. Further studies of biophysics and physiology of endothermic insects during flight are needed to correct these deficiencies. Application of biophysical techniques has allowed predictions of behavior of flying insects based onprinciples of heat exchange which cannot be examined directly. Analyses of endothermy of restinghoneybee swarms and hives indicate that these “superorganisms” regulate temperature rather precisely over a remarkable range of environmental temperature using mechanisms equivalent to thoseused by resting endothermic vertebrates.

Temperature-Dependent Maximum Daily Consumption of Juvenile Salmonids by Northern Squawfish (Ptychocheilus oregonensis) from the Columbia River

Maximum daily consumption rate (Cmax as ration or number) of northern squawfish (Ptychocheilus oregonensis) from the Columbia River increased exponentially as a function of temperature. Predator weight did not explain a significant independent proportion of variation in Cmax. The mean maximum daily ration, determined from replicate ad libitum feeding on juvenile Pacific salmon (Oncorhynchus spp.), was 0.47, 0.70, 3.39, and 4.50 cg∙g−1 at 8.0, 12.5, 17.0, and 21.5 °C, respectively. The corresponding mean daily number eaten was 0.50, 1.17, 4.25, and 7.01 prey per predator at the four increasing temperatures. To quantify the temperature-dependent consumption relation, replicate Cmax data within the preferred temperature range were fitted to exponential and exponential sigmoid models. On the basis of a knowledge of thermal relations of northern squawfish, we combined hypothetical Cmax data at temperature extremes with our mean experimental results to fit an algorithm suitable for use in simulation modeling. Both the generalized gamma and biological-rate (Thornton and Lessem. 1978. Trans. Am. Fish. Soc. 107: 284–287) algorithms were suitable to describe a hypothetical temperature–Cmax model over the entire environmental temperature range of 0–27 °C observed in the Columbia River.

Effects of temperature on tilt evoked swimming in the crabs Carcinus and Macropipus

1. 1.|Integrated muscle activity, total number of limb beats and the maximum instantaneous limb beat frequency were measured in crabs during a standardized tilt regime at a series of different water temperatures between 10 and 25°C. 2. 2.|Total integrated activity and total number of limb beats showed a general increase for a decrease in temperature in all groups. Frequency of limb beat was always higher for Macropipus depurator than for Carcinus maenas, with M. depurator showing an increase and C. maenas a decrease in frequencies at extreme temperatures. 3. 3.|The temperature of acclimation of C. maenas affected the response of the crab in all parameters studied while all the results can be related to the size and normal environmental temperature range of the two species studied.

Microcalorimetric Investigations on the Energy Metabolism of Lizards

ABSTRACTThe energy metabolism of three lizard species (Podarcis milensis, Podarcis muralis and Lacerta agilis) was investigated by means of microcalorimetry and polarography over the range of environmental temperatures between 17 and 35 °C encountered by active lizards during summer in Europe. In non-stimulated animals, the maximum and mean heat production rates were highest around 30°C for all species and amounted to 3.9±l.lmWg−1 and 2.1±0.5mWg−1, respectively. Resting metabolism contributed approximately 60% to the mean routine heat dissipation; the remainder originated from locomotory activity, 43% of which was based on anaerobic energy metabolism. From simultaneous determinations of heat dissipation and oxygen consumption, an average oxycaloric equivalent of 18.6±3.2 J ml−1O2 was calculated, which rose to 26.6±7.1 J ml−1O2 during short bursts of locomotion.

Persistence of a Circannual Rhythm of Plasma Prolactin Concentrations in Ewes Exposed to a Constant Equatorial Photoperiod1

Circulating concentrations of prolactin were monitored for 3 yr in intact ewes kept either outdoors or indoors in a fixed equatorial photoperiod (12L:12D) and restricted range of environmental temperatures. Prolactin data were analyzed by spectral analysis. In all ewes kept outdoors, concentrations of prolactin showed robust circannual rhythms with a single predominant period of 359 days. In ewes kept indoors, the range of significant periods varied from 35 to 532 days. Although all ewes kept indoors showed a significant rhythm with a period of 354 days, this clearly was not the predominant period in all. The amplitude of the rhythm in ewes kept indoors was significantly lower (p less than 0.01) than that of ewes kept outdoors. Although the annual rhythm of circulating prolactin typical of ewes kept outdoors was significantly compromised in animals kept under a constant 12L:12D photoperiod and restricted environmental temperature range, there was evidence of an endogenous circannual rhythm.

Cuticular hydrocarbons of adult Onymacris bicolor (HAAG) and Onymacris boschimana (Péringuey) (Coleoptera: tenebrionidae)

1. 1. The cuticular hydrocarbons of O. bicolor (OBC) and O. boschimana (OBS) comprise n- alkanes (OBC, n C 19-n C 30 , 31.0%; OBS, n C 20-n C 30 , 22.8%), 3-methylalkanes (OBC, C 24-C 28, approx. 15.6%; OBS, C 24-C 30, 23.7%), internally branched monomethylalkanes (OBC, C 23-C 32, 29.8%; OBS, C 25-C 32, approx. 34.3%), dimethylalkanes (OBC, C 23-C 39, approx. 19.8%; OBS, C 27-C 33, 18.6% and trimethylalkanes (OBC, C 26-C 41, 1.4%; OBS, C 32 and C 34 0.2%). Unusual 3,5-dimethylalkanes C 29 and C 31) were identified in OBS and tetramethylalkanes C 39, C 40 and C 42) were tentatively identified in OBC (total 2.4%) 2. 2. OBC and OBS have many, though not all, of the hydrocarbon characteristics of tribe, Adesmiini. Of the hydrocarbon characteristics of genus Onymacris, OBC and OBS have high proportions of 3-methylheptacosane and 3-methynonacosane respectively, though neither species has n C 31 and the problem remains of characterizing the genus and separating it from other closely-related genera. 3. 3. The hydrocarbon compositions of five congeneric species reflect the subdivision of genus Onymacris. Group 1 species, OBS and OR ( O. rugatipennis) have fewer hydrocarbons with a narrower chain length range than group 2 species, OP ( O. plana), OM ( O. marginipennis) and OBC and their hydrocarbon mixtures contain a few components in high abundance rather than several components in moderate abundance as in group 2 species. The close relationship between the “white” Onymacris species OM and OBC is reflected in their hydrocarbon compositions which show marked qualitative and quantitative similarities. 4. 4. Dimethylalkane biosynthesis in OBC is examined. Slight changes in the incorporation sequence of derivatives during chain elongation can affect branch position and chain length. The early incorporation of branch donors during chain elongation results in the biosynthesis of dimethylalkanes with variable branching patterns. 5. 5. OBS, an inland species, has a hydrocarbon mixture with a higher and narrower melting range than OBC, a coastal species. The composition and melting characteristics of hydrocarbon mixtures are considered in relation to their proposed function as a fluid matrix and to the range of environmental temperatures encountered by species.

Is increased metabolism in rats in the cold mediated by the thyroid?

1. In the rat variation of metabolic heat production is the principal effector of thermoregulation. There is a continuous relationship between ambient temperature and metabolic rat over the whole range of tolerable environmental temperature. The mechanism that controls metabolic rate is unknown; this paper reports an attempt to test whether thyroid hormones provide the controlling pathway. 2. First, the changes in metabolic rate and in the plasma concentrations of thyroid stimulating hormone (TSH), triiodothyronine (T3) and thyroxine (T4) were measured in rats living in a controlled environment, first at 23 degrees C and then at 6 degrees C. Metabolic rate increased from approximately 290 to 470 kJ day-1 when the temperature was lowered, a factor of ca 1.6, and the diurnal rhythm disappeared. The concentration of TSH increased from approximately 320 to 450 ng ml-1 (with loss of diurnal rhythm) and of T3 from ca 0.7 to 1.0 nmol l-1, a factor of ca 1.4 in each case. T4 concentration did not change. 3. Next, a dose schedule of T3 was found that, when injected I.V. via indwelling jugular cannulae in the same rats in an environment at 23 degrees C, maintained an increase in T3 concentration rather greater than had been found at 6 degrees C. 4. This dose of T3, given to the same rats at 23 degrees C, did not affect metabolic rate (or its diurnal pattern). 5. It is therefore unlikely that the increase in T3 concentration evoked the increase in metabolic rate when ambient temperature was changed from 23 to 6 degrees C; and therefore that the thyroid controls variation of metabolic rate in 'everyday' thermoregulation in the rat.

Effect of dietary ascorbic acid supplementation on the performance of brown-egg layers and egg quality

Five experiments were conducted to evaluate the effects of dietary ascorbic acid (AA) on the performance and egg quality of brown-egg layers. The trials were started during November and continued into September of the following year so that a range of environmental temperatures was involved. Egg production rates, body weight changes, and shell quality were not significantly affected by AA supplementation in any experiment. AA significantly increased the egg weight of hens at peak of lay in one of two experiments in which a low-protein diet was used. No other significant interactions between protein level and AA supplementation for other parameters were observed. Albumen quality, as measured by Haugh units, was significantly increased by AA (1000 mg kg −1) in only one experiment. It was concluded that supplemental AA for brown egg-laying strains has little practical value, at least when hens are kept under generally unstressful conditions.

Prediction of temperature profiles in the human skin and subcutaneous tissues

Exact mathematical solutions in terms of confluent hypergeometric and Airy's functions are obtained to study the steady state temperature distributions in human skin and subcutaneous tissues (SST). It is assumed that the skin is exposed to an air environment and heat transfer from the skin occurs by convection, radiation and evaporation. A mathematical model of the SST, accounting for heat conduction, perfusion of the capillary beds and metabolic heat productions of the dermis and subcutaneous tissues, has been solved to obtain interface temperatures for a wide range of environmental temperatures, rates of evaporation of sweat, wind speeds and relative humidities. The solutions provide inter-relationships between interface temperatures, thermal conductivities, metabolic heat production, blood perfusion, thicknesses of various layers of SST and ambient temperature.

Behavioural thermoregulation in three species of robber flies (Diptera, Asilidae: Efferia)

Robber flies of three species of the genus Efferia (Diptera: Asilidae) were active in a grassland habitat across a wide range of diurnal environmental temperatures. Perch height, posture and orientation of the body axes varied with environmental temperature. Early in the day, the flies warmed up by perching with their ventral surfaces close to the ground and basking with their longitudinal and dorsoventral body axes perpendicular to the direction of the sun. As the day progressed, they perched with their bodies raised off the surface and eventually moved onto surfaces above the ground, so that the air temperatures experienced remained within the relatively narrow range of approximately 27–35°C. Changes in perch height and orientation of the body axes resulted in significant changes in operative body temperatures. At the highest environmental temperatures, E. bicaudata and E. frewingi perched with their longitudinal axes towards the sun, while E. staminea showed no tendency to orient in any particular direction. The significance of behavioural thermoregulation and differences among the species in perch height and in orientation at high environmental temperatures are discussed.

The influence of ambient temperature on sleep characteristics in the aged cat

Sleep characteristics were compared in young adult and aged cats over a range of environmental temperature from 5 to 35 °C. Although both groups exhibited sleep disruptions as ambient temperatures decreased, transient arousals were increased at temperature extremes in the aged group compared to young adults. Declining efficiency or thermoregulatory control and increased sensitivity to environmental temperature in the elderly may contribute to the changes in sleep quality which occur during the aging process

On testing methodology of thermosetting dielectrics subjected to partial discharges: effect of temperature

Following the idea of performing tests in environmental conditions as similar as possible to the real working ones, many sets of partial discharge tests carried out on an epoxy resin within a broad environmental temperature range are reported on. Life tests were carried out on specimens with a calibrated, enclosed cavity and with embedded electrodes. In the tests performed at temperatures higher than ambient, an interesting strong decrease of data scattering resulted and emphasis on the subject is given. Actually, a strong and unexpected effect was found of the residual mechanical casting stress inside the resin on time-to-breakdown, depending on the difference between the material glass transition temperature and the temperature used in the test. Further data such as discharge amplitude distributions, discharge repetition rate and inception and extinction voltages at the investigated temperatures are also reported and commented upon.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Lactate dehydrogenases in antarctic and temperate fish species

1. 1. The kinetics of lactate dehydrogenase (both forward and back reaction) in cardiac and skeletal muscle of an Antarctic teleost have been compared with a temperate teleost of comparable morphology and ecology. 2. 2. In both species the forward reaction (pyruvate to lactate) is maximally activated at 2.5–4 mM pyruvate and inhibited above this level. 3. 3. The Michaelis constant (K m ) for pyruvate is not significantly different between muscle types or between species when measured at their normal environmental temperature. 4. 4. K m for pyruvate varies with temperature in a positive direction. 5. 5. The back reaction (lactate to pyruvate) is maximally activated by 12–16 mM lactate but only in skeletal muscle of the antarctic species is there inhibition above this level. 6. 6. The K m for lactate is significantly (P<0.05) lower in the Antarctic fish cardiac muscle. 7. 7. While the two species are morphologically and ecologically similar, differences at the biochemical level are discussed with respect to environmental temperature range and conservation of enzymic characteristics.

Statistics on charge exchange and charge generation during single collisions of ice particles

Abstract Individual collisions between an evaporating cylindrical ice target 4 mm in diameter and irregularly shaped evaporating ice crystals with sizes 250–1000 μm and charges between − 300 and + 120 fC have been observed over a range of environmental temperatures and pressures from − 10 to −40°C and from 400 to 1010 mbar. The charge transferred was highly variable and often opposite in sign to the incoming charge, but on average about one-fifth of the projectile charge was transferred to the target. When the projectile charge was less than the minimum measurable charge of 6 fC, the average charge per collision conferred on the target was + 7.4 ± 0·9 fC which was opposite in sign to that found by previous workers who reported a net charge transfer of about − 10 fC which was independent of projectile charge. The differences in the results of the present work support an earlier postulate by the present authors that the magnitude and polarity of the transferred charge are controlled by microscopic scale dif...

Effect of dermorphin on body temperature in rats

The effect of dermorphin on regulation of body temperature was studied in the rat under extreme and thermoneutral environmental temperatures and in different nutritional states. Intracerebroventricular (icv) injections of dermorphin at dose levels of 10, 50, 100 ng/rat produced hypothermia in animals placed in cold temperatures (-10 degrees C and +4 degrees C) and hyperthermia at ambient (+22 degrees C) and higher temperatures (+34 degrees C). These data emphasize the importance of using a wide range of environmental temperatures in studying drug effects on thermoregulation. To determine whether the effect of dermorphin on body temperature was related to the nutritional state of the animal, as observed with other neuropeptides (i.e., bombesin, litorin), the thermoregulatory response was followed in fed and fasted rats. The same results were obtained in both experimental groups. In all cases, dermorphin change in body temperature was mediated via an action on typical opioid receptors since it was completely prevented by pretreatment with naloxone.

The effect of temperature on size and development in three species of benthic copepod.

The effect of temperature on the size and development times of three benthic cyclopoid copepods, Acanthocyclops viridis, A. vernalis and Macrocyclops albidus were investigated within the normal environmental temperature range (5°C-20°C). Adult weight decreased as temperature increased. All three species complete their development at 5°C and development times at all temperatures are presented as curvilinear logarithmic temperature functions. The duration of development decreases as temperature rises. The results are compared with those reported else-where for benthic and planktonic species and the ecological implications are discussed.

Respiratory studies on two benthic copepods Acanthocyclops viridis and Eucyclops agilis at environmental temperatures.

The rate of oxygen consumption in all developmental stages of two benthic cyclopoid copepod species, Acanthocyclops viridis (Jurine) and Eucyclops agilis (Koch, Sars) was investigated at temperatures between 5° C-20° C, which are reflective of the environmental temperature range of the benthic zone in Esthwaite Water, Cumbria, from which the organisms were derived. The larger species, A. viridis was found to have a temperature insensitive metabolism, whereas E. agilis showed a marked temperature response in respiratory function. Gravid and non-gravid females had similar rates of respiration except at 15° C-20° C in E. agilis. Males exhibited much lower respiration rates than females, but higher weight specific respiration rates; these differences were largely attributable to size differentials between the sexes. Estimates of swimming activity were made and these were related to the patterns of respiratory function observed.