Body temperature and rate of O2 consumption in Chinese pangolins

1986 ◽  
Vol 250 (3) ◽  
pp. R377-R382 ◽  
Author(s):  
M. E. Heath ◽  
H. T. Hammel

Body temperatures and rates of O2 consumption and CO2 production were measured in four Chinese pangolins (Manis pentadactyla) during short-term exposures (2-4 h) to ambient temperatures (Ta) of 10-34 degrees C. At Ta less than 27 degrees C the pangolins curled into a sphere. At Ta greater than 28 degrees C the animals laid on their backs with their soft abdominal skin exposed. Rectal temperatures between 33.4 and 35.5 degrees C were recorded from animals exposed to Ta of 10-32 degrees C. At Ta greater than or equal to 32 degrees C the animals appeared to be markedly heat stressed, rate of breathing was elevated, and core temperature rose somewhat. Resting metabolic rates averaged 3.06 ml O2 X kg-1 X min-1. This is significantly lower than would be predicted from the relationship between body mass and metabolic rate established by Kleiber (The Fire of Life: an Introduction to Animal Energetics. New York: Wiley, 1975) for other eutherian mammals. The magnitude of the metabolic response to Ta below the lower critical temperature was inversely correlated to the mass of the pangolin, the slope being greatest for the smallest animals. Respiratory quotients of 0.85-1.0 were observed.

2006 ◽  
Vol 274 (1607) ◽  
pp. 287-293 ◽  
Author(s):  
Craig R White ◽  
Tim M Blackburn ◽  
Graham R Martin ◽  
Patrick J Butler

A classic example of ecophysiological adaptation is the observation that animals from hot arid environments have lower basal metabolic rates (BMRs, ml O 2  min −1 ) than those from non-arid (luxuriant) ones. However, the term ‘arid’ conceals within it a multitude of characteristics including extreme ambient temperatures ( T a , °C) and low annual net primary productivities (NPPs, g C m −2 ), both of which have been shown to correlate with BMR. To assess the relationship between environmental characteristics and metabolic rate in birds, we collated BMR measurements for 92 populations representing 90 wild-caught species and examined the relationships between BMR and NPP, T a , annual temperature range ( T r ), precipitation and intra-annual coefficient of variation of precipitation ( P CV ). Using conventional non-phylogenetic and phylogenetic generalized least-squares approaches, we found no support for a relationship between BMR and NPP, despite including species captured throughout the world in environments spanning a 35-fold range in NPP. Instead, BMR was negatively associated with T a and T r , and positively associated with P CV .


1972 ◽  
Vol 94 (4) ◽  
pp. 853-861
Author(s):  
J. D. Stachiw

Temperature and the seating arrangement in the flange have a significant effect on the critical pressure of conical acrylic windows. Over 400 acrylic windows with 90 deg conical angle were used in this study to establish experimentally the relationship between thickness to minor diameter ratio (t/D), temperature, seating arrangement in the flange, and critical pressure under short term hydrostatic loading. The data indicates that utilizing 70 deg F as standard of comparison, there is, approximately 20 percent increase in critical short term pressure when 32 deg F, and 20 percent decrease when 90 deg F ambient temperatures are utilized, respectively. It was also found that the short term critical pressure of some conical acrylic windows is influenced by the seating arrangement in the flange. As a rule, an increase in the ratio of minor window diameter to minor flange opening diameter (D/Df) raised the short term critical pressure of windows with t/D ≥ 0.375 significantly. For windows with t/D < 0.375, it did not raise the critical pressure.


1984 ◽  
Vol 246 (6) ◽  
pp. R963-R967 ◽  
Author(s):  
K. J. Nilssen ◽  
H. K. Johnsen ◽  
A. Rognmo ◽  
A. S. Blix

The purpose of this study was to determine whether a convenient relationship could be found between heart rate (HR) and energy expenditure at rest and during running in the high arctic Svalbard reindeer (SR) and the subarctic Norwegian reindeer (NR). Measurements of HR and energy expenditure (O2 consumption) were made at different ambient temperatures, at rest, and during running at different speeds during both summer and winter. Cost of transportation (Science 177: 222-228, 1972) was 3.56 and 2.67 J X g-1 X km-1 in SR and NR, respectively. The y-intercept value obtained for NR was close to the predicted value (J. Exp. Biol. 97: 1-22, 1982), whereas that of SR was much lower. In NR the relationship between HR and energy expenditure at running speeds from 0 to 9.2 km X h-1 is, regardless of ambient temperature (in the -30 to +10 degrees C range), described by the following equations: y = 8.04x + 48.70, r = 0.92, n = 27 (summer); and y = 7.48x + 31.20, r = 0.95, n = 52 (winter). In SR, the corresponding equations were y = 7.60x + 49.20, r = 0.94, n = 29 (summer); and y = 8.90x + 32.10, r = 0.96, n = 44 (winter), where y is HR (beats X min-1) and x is metabolic rate (W X kg-1).


2001 ◽  
Vol 91 (2) ◽  
pp. 603-612 ◽  
Author(s):  
Renata C. H. Barros ◽  
Mary E. Zimmer ◽  
Luiz G. S. Branco ◽  
William K. Milsom

We examined the magnitude of the hypoxic metabolic response in golden-mantled ground squirrels to determine whether the shift in thermoregulatory set point (Tset) and subsequent fall in body temperature (Tb) and metabolic rate observed in small mammals were greater in a species that routinely experiences hypoxic burrows and hibernates. We measured the effects of changing ambient temperature (Ta; 6–29°C) on metabolism (O2 consumption and CO2 production), Tb, ventilation, and heart rate in normoxia and hypoxia (7% O2). The magnitude of the hypoxia-induced falls in Tb and metabolism of the squirrels was larger than that of other rodents. Metabolic rate was not simply suppressed but was regulated to assist the initial fall in Tb and then acted to slow this fall and stabilize Tb at a new, lower level. When Ta was reduced during 7% O2, animals were able to maintain or elevate their metabolic rates, suggesting that O2 was not limiting. The slope of the relationship between temperature-corrected O2 consumption and Taextrapolated to a Tset in hypoxia equals the actual Tb. The data suggest that Tset was proportionately related to Ta in hypoxia and that there was a shift from increasing ventilation to increasing O2extraction as the primary strategy employed to meet increasing metabolic demands under hypoxia. The animals were neither hypothermic nor hypometabolic, as Tb and metabolic rate appeared to be tightly regulated at new but lower levels as a result of a coordinated hypoxic metabolic response.


1994 ◽  
Vol 266 (2) ◽  
pp. R387-R391 ◽  
Author(s):  
T. Matsuoka ◽  
A. Dotta ◽  
J. P. Mortola

We tested the hypothesis that the sinoaortic afferents may contribute to normoxic thermogenesis and to the magnitude of the hypometabolic response to hypoxia. Adult rats were either sinoaortic denervated (SAX; n = 20) or sham operated (Sham; n = 20). A few days after the operation, gaseous metabolism [O2 uptake (VO2) and CO2 production (VCO2)] was measured with an open-flow system at ambient temperatures (Tamb) of 20, 25, 30, and 35 degrees C as the animal was resting awake. At thermoneutrality (Tamb 30 degrees C) or higher Tamb there was no difference in VO2 or VCO2. Below thermoneutrality, metabolic rate was significantly lower in SAX than in Sham animals (-14 and -16% at 20 and 25 degrees C, respectively). Colonic temperature and arterial PO2 were also slightly less, whereas arterial PCO2 and pH, mean arterial pressure, and heart rate did not differ significantly between the two groups. Exposure to acute hypoxia (10% inspired O2, 20-30 min) at Tamb 20 and 25 degrees C significantly reduced VO2 in both groups to a similar value; hence, at either Tamb, the metabolic drop during hypoxia in Sham animals was larger than that in SAX animals. Hypercapnia (5% CO2 breathing) did not change VO2 in either group. We conclude that in the rat at Tamb slightly below thermoneutrality, the sinoaortic afferents 1) provide a small but significant contribution to normoxic thermogenesis and 2) are not required for the manifestation of the drop in metabolism during hypoxia.


PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5725 ◽  
Author(s):  
Imran Khaliq ◽  
Christian Hof

Metabolic critical temperatures define the range of ambient temperatures where endotherms are able to minimize energy allocation to thermogenesis. Examining the relationship between metabolic critical temperatures and basal metabolic rates (BMR) provides a unique opportunity to gain a better understanding of how animals respond to varying ambient climatic conditions, especially in times of ongoing and projected future climate change. We make use of this opportunity by testing the heat dissipation limit (HDL) theory, which hypothesizes that the maximum amount of heat a species can dissipate constrains its energetics. Specifically, we test the theory’s implicit prediction that BMR should be lower under higher metabolic critical temperatures. We analysed the relationship of BMR with upper and lower critical temperatures for a large dataset of 146 endotherm species using regression analyses, carefully accounting for phylogenetic relationships and body mass. We show that metabolic critical temperatures are negatively related with BMR in both birds and mammals. Our results confirm the predictions of the HDL theory, suggesting that metabolic critical temperatures and basal metabolic rates respond in concert to ambient climatic conditions. This implies that heat dissipation capacities of endotherms may be an important factor to take into account in assessments of species’ vulnerability to climate change.


Author(s):  
Shivananda B Nayak ◽  
Dharindra Sawh ◽  
Brandon Scott ◽  
Vestra Sears ◽  
Kareshma Seebalack ◽  
...  

Purpose: i) To determine the relationship between the cardiac biomarkers ST2 and NT-proBNP with ejection fraction (EF) in heart failure (HF) patients. ii) Assess whether a superiority existed between the aforementioned cardiac markers in diagnosing the HF with reduced EF. iii) Determine the efficacy of both biomarkers in predicting a 30-day cardiovascular event and rehospitalization in patients with HF with reduced EF iv) To assess the influence of age, gender, BMI, anaemia and renal failure on the ST2 and NT-proBNP levels. Design and Methods: A prospective double-blind study was conducted to obtain data from a sample of 64 cardiology patients. A blood sample was collected to test for ST2 and NT-proBNP. An echocardiogram (to obtain EF value), electrocardiogram and questionnaire were also obtained. Results: Of the 64 patients enrolled, 59.4% of the population had an EF less than 40%. At the end of the 30- day period, 7 patients were warded, 37 were not warded, one died and 17 were non respondent. Both biomarkers were efficacious at diagnosing HF with a reduced EF. However, neither of them were efficacious in predicting 30-day rehospitalization. The mean NT-proBNP values being: not rehospitalized (2114.7486) and 30 day rehospitalization (1008.42860) and the mean ST2 values being: not rehospitalized (336.1975), and 30-day rehospitalization. (281.9657). Conclusion: Neither ST2 or NT-proBNP was efficacious in predicting the short- term prognosis in HF with reduced EF. Both however were successful at confirming the diagnosis of HF in HF patients with reduced EF.


2005 ◽  
Vol 156 (8) ◽  
pp. 288-296
Author(s):  
Vittorio Magnago Lampugnani

In the first half of the 19th century scientific philosophers in the United States, such as Emerson and Thoreau, began to pursue the relationship between man and nature. Painters from the Hudson River School discovered the rural spaces to the north of New York and began to celebrate the American landscape in their paintings. In many places at this time garden societies were founded, which generated widespread support for the creation of park enclosures While the first such were cemeteries with the character of parks, housing developments on the peripheries of towns were later set in generous park landscapes. However, the centres of the growing American cities also need green spaces and the so-called «park movement»reached a first high point with New York's Central Park. It was not only an experimental field for modern urban elements, but even today is a force of social cohesion.


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