Keywords: Core temperature; Face skin temperature; Cheek thermal resistance; Cold exposure; Exercise 相似文献
- (1)Final temperature preferendum of juvenile (0.9–1.9 g) and adult (5.2–12.5 g) angelfish Pterophyllum scalare were determined with acute and gravitation methods. The final preferenda were similar, independent of the method and development stage (29.0–31.1°C).
- (2)The critical thermal maxima (CTMax) for juveniles were 36.9°C, 37.6°C, 40.6°C, 40.8°C and for adults 38.4°C, 38.6°C, 41.0°C, 42.1°C. Adult angelfish CTMax was slightly higher than in juveniles (1°C; P<0.05); the endpoint of CTMax was the onset of spasms.
- (3)The acclimation response ratio for both stages had an interval of 0.33–0.44; these values are in agreement with results for subtropical and tropical fishes.
- (4)Therefore it is recommended that angelfish cultivation should be consistent with temperatures that do not change abruptly throughout the year and temperature maximum does not exceed 30°C.
2. The distribution of finger skin temperatures was quite similar at ambient temperature ranges 0 to −10 °C and −10 to −20 °C, while at −20 to −30 °C the finger temperatures were clearly lower.
3. At different ambient temperature ranges, 20–69% of finger temperatures were low enough to cause cold thermal sensations.
4. Sensation of cold was experienced at a finger temperature of 11.6±3.7 °C (mean±SD). 相似文献
- 1. The present study examined the effect of the thermal state of the body (as reflected by rectal temperature) on cheek skin temperature and thermal resistance in active and inactive subjects.
2. Active subjects were exposed to a 30 min conditioning period (CP) (0 °C air with a 2 m/s wind), followed immediately by a 30 min experimental period (EP) (0 °C with a 5 m/s wind). Inactive subjects were exposed to a 30 min CP (22 °C air with no wind), followed immediately by a 45 min EP (0 °C air with a 4.5 m/s wind). The CP period was used to establish a core temperature difference between the active and inactive subjects prior to the start of EP. The 0 °C exposure was replaced with a −10 °C ambient air exposure and the experiment was repeated on a separate day. Subjects were comfortably dressed for each ambient condition.
3. Cheek skin temperature was not significantly higher in active subjects when compared to inactive subjects, but thermal resistance was higher in active subjects.
4. Cheek skin temperature and thermal resistance both decreased as ambient temperature decreased from 0 to −10 °C. The lower cheek thermal resistance at −10 °C may have been due to a greater cheek blood flow as a result of cold-induced vasodilation.
1. 1.The forearm of 5 female subjects ws thermally stimulated by 2 sets of interposed servo-thermodes that respectively drove skin temperature at ±0.1°C.s−1 for 25 s and then held it constant. Mean skin temperature remained constant. The sequence was repeated at adapting temperatures between 22.5 and 37.5°C.
2. 2.Thermal sensations, continuously reported by the position of a dial, were warmer for heterogeneous thermal stimuli than for homogeneous stimuli when mean skin temperature was greater than 30°C and cooler when less than 27.5°C.
3. 3.This phenomenon is inconsistent with a single additive contribution of “warm” and “cold” information to thermal sensations.
Author Keywords: Man; thermal sensation; skin temperature 相似文献
- 1. 1. The thermal death point of the water flea Daphnia magna (age < 24 h, cultured at 20°C) varied considerably depending on the method used. The median lethal dose (LD50), induced by an acute 24 h heat exposure was 34.8°C. It was 37.8°C following a thermal shock for 15 min, and it was 39.4°C when a continuous temperature increase (0.2°C/min) was used.
- 2. 2. Heat death temperature of daphnids was related to the acute heating rate.
- 3. 3. The logarithm of median lethal time (Lt50) of daphnids, kept at a constant high temperature, had a linear relationship to temperature (°C) within the range of 28.0–38.5°C.
- 4. 4. The mortality after heat exposure increased with recovery time at 20°C for up to 3 days.
- 5. 5. The animals which survived the heat exposure produced eggs and offspring. Furthermore, no time lag in development between the control and heat exposure group was observed.
- 6. 6. The comparison of the results made by different heat tests categorized to Methods 1 and 2 by Precht (1973), for use in the determination of lethal limits of ectotherms, has been discussed.
1. 1.|The germination of tomato “C38” seeds exposed to periodical white incandescent light occurs from 6.0° ± 0.2°C to 37.5° ± 0.2°C, being rate-limited for 10.3° T 25.9°C, and elsewhere limited by the germination capacity.
2. 2.|Rate averages are linearly T-dependent outside their optimum range (25.9° T 29.5°C) and rate variances are typically heterogeneous.
3. 3.|The smooth curvilinear Arrhenius plot indicates that diffusion processes cannot be rate-limiting outside the interval 25.9° T 29.5°C, whereas phase transitions and (or) transconformation of proteins may limit the rate above 34.9°C and, by opposite effects, below 15.3°C.
4. 4.|The thermal communication between the environment and the germinating seed proceeds by a temperature signal which is quenched by random thermal noise at T 11.2°C and at T 34.0°C.
Author Keywords: Temperature dependence of germination; Arrhenius plot of germination; germination rate; germination capacity; cynchronization of germination; temperature signal in germination; diffusion in germination; thermodenaturation of proteins; seed germination; tomato germination; Lycopersicon esculentum 相似文献
- 1. 1. The preferred temperature of Bulla gouldiana is 26.7–28.7°C.
- 2. 2. In constant scotophase, photophase, and light and dark photoperiod the organisms do not have a diel cycle of thermoregulation.
- 3. 3. It takes the animal 6–16 h to reach the preferred temperature.
- 4. 4. The lowest and highest temperatures visited were 11 and 33°C.
- 5. 5. Spawning of the species occurred in the thermal gradient between 27 and 28.5°C.
The mean values for SCPs of adults fed at 20°C were −14.5±2.4°C (31 males) and −10.3±1.3°C (29 females). The distribution of the SCPs of these control adults was unimodal. No significant differences were observed in either mean wet weight or mean dry weight between males and females.
The mean values for SCPs of adults starved for 1 month at 20°C were found to be bimodal due to sexual dimorphism. The mean SCPs for males was lower (−17±2.6°C; 28) than that for females (−11.2±1.8°C; 26). No significant differences were observed in either mean dry weight or wet weight between males and females.
The SCPs of both fed and starved larvae, kept for 1 month at 20°C were −12.3±2.4°C (fed) and −18.0±2.6°C (starved). 相似文献
2. Induction kinetics of delayed light varied depending on temperature. It was found to be composed of two phases; one was an initial rapid rise followed by a rather fast decline to a low steady state level (fast phase), and the other was a slow increase after the initial rapid rise to the maximum followed by an insignificant slow decrease to a high steady state level (slow phase). The fast phase existed between −175 and 40 °C with the maximum at −40 °C, while the slow phase, between 0 and 40 °C with the maximum at 25 °C.
3. The intensity of delayed light at −175 °C was found to be less than one fiftieth that at 0 °C, and no delayed light emission was observed at −196 °C within experimental accuracy. This is in contrast to the results reported by Tollin, G., Fujimori, E. and Calvin, M. ((1958) Proc. Natl. Acad. Sci. U.S. 44, 1035–1047) in which the intensity of delayed light measured at −170 °C was about a half that at 0 °C.
4. The induction of delayed light measured at −96 °C was found to be significantly suppressed by the preillumination at −196 °C. This finding suggests that the primary photochemical event still survives at −196 °C without emission of delayed light.
5. Decay kinetics of delayed light after the flash excitation revealed the presence of at least two decay components. A slow decay component with a half decay time of several tens of milliseconds was observed at temperatures higher than 0 °C. A fast decay component with a half decay time of about 0.2 ms was observed at temperatures between −120 and 25 °C. The decay rate of this component was slightly retarded on cooling.
6. The System II particles derived from spinach chloroplasts with digitonin treatment showed a temperature dependence of delayed light similar to that of the chloroplasts. System I particles, on the other hand, scarcely emitted the delayed light at any temperature between 40 and −196 °C. 相似文献
The CTmax was significantly lower in O. eremita (45.6±0.7 °C) than in G. nobilis (48.5±0.6) and C. aeruginosa (51.4±0.9 °C).
An increase of 10 °C (30–40 °C) induced a 2-fold increase of the water loss in C. aeruginosa and O. eremita (Q10=2.10±0.12 and 2.13±0.20, respectively). In the range from 40 to 45 °C to CTmax a strong increase of the water loss was observed in O. eremita and C. aeruginosa, respectively. Body water losses were significantly lower in C. aeruginosa than in O. eremita and G. nobilis over the range 20 °C—CTmax; no significant difference occurred between G. nobilis and O. eremita. 相似文献
1. 1.|In the freshwater fish Chalcalburnus chalcoides, an increase in the body (standard) size caused decreases in the upper LT-50 from 36.6° to 36.0°C and lower LT-50 from 6.3° to 5.3°C
2. 2.|The fish acclimated to constant temperatures between 10°C and 30°C showed reasonable heat acclimation and also reasonable cold acclimation. Thus, an increase in the acclimation temperature from 10°C to 30°C caused increases in the upper LT-50 from 34° to 36.2°C and the lower LT-50 from 1.25 to 6.5°C.
3. 3|The mean survival time — temperature curves of 10°, 20° and 30°C acclimated fish at various constant temperatures showed decreased in the survival tim ewith increasing lethal temperatures. Furthermore, an increase in the acclimation temperature causes a shift in the survival duration-temperature curve to the right, i.e., the fish become more heat resistant. Thus, the mean survival duration of 10°, 20° and 30°C acclimated fish at 35°C were 7.5, 79.6 and 530 minutes, respectively.
4. 4.|The effect of the thermal experience to changing lethal temperatures depends on the first lethal temperature to which the fish were exposed as well as the sequence of temperature changes. In the experiments in which the first lethal temperatures were between 32° and 34°C and the temperature was varied in an ascending order, their thermal resistance was increased and the fish required 114 to 174% of the expected lethal doses to die while in the experiments in which the starting temperature were between 38° and 40°C and the temperature varied in descending order, the fish become more sensitive to the upper lethal temperature and they died after receiving only 62 to 81% of the expected lethal doses. Thus, with a gradual increase in the lethal temperature, the fish show additional acclimation in the zone of resistance which in turn causes an increase in the thermal resistance. This may have ecological significance in nature.
Author Keywords: acclimation; lethal temperatures; temperature change; survival 相似文献