scholarly journals Harlequin Frogs (Lysapsus) prefer mild places to park

2020 ◽  
Author(s):  
Carolina Cunha Ganci ◽  
Zaida Ortega ◽  
Diogo B. Provete
Keyword(s):  
Response Time ◽  
Thermal Sensitivity ◽  
Thermal Conditions ◽  
Additive Models ◽  
Locomotor Performance ◽  
Extreme Temperatures ◽  
Experimental Conditions ◽  
Jumping Performance ◽  
Total Distance ◽  
Jump Distance

AbstractTemperature affects most aspects of ectotherms’ life history, including physiology and behavior. Studying thermal sensitivity of jumping performance in frogs can help understanding the influence of temperature on different aspects of frog life. Still, studies on the effects of temperature on amphibians are commonly carried out on terrestrial and tree species, creating a gap for aquatic species. We experimentally tested the thermal sensitivity of jumping performance of the Uruguay Harlequin Frog, Lysapsus limellum, assessing three measures: response time, distance of first jump, and total distance travelled. We hypothesized that individuals submitted to extreme temperatures would increase response time, decrease first jump distance, and increase total jump distance. We used an arena with a gradient of air temperature (Ta) ranging from 20 to 40 °C. We placed frogs at different Ta and stimulated them to jump. Then, we analysed the influence of Ta on the three estimates of jumping performance, using generalized additive models. We found that temperature affected all three measurements of jumping performance, but some relationships were stronger than others. Extreme temperatures increased response time, reduced first jump distance, and increased total distance. The effect was weaker for response time and first jump distance, but substantially stronger for total distance jumped. Although individuals under extreme temperatures experience a reduced jumping performance, they travelled longer distances to find areas with milder temperatures. Thus, we showed that L. limellum thermoregulates by means of behavior, moving through places at different thermal conditions. Additionally, benefits of displacing to thermally suitable places -in terms of enhanced jumping performance-are bigger than the costs of jumping at reduced locomotor performance, at least under experimental conditions. Our results can help understand how climate change affects the locomotor performance of Neotropical amphibians.

scholarly journals Geographic variation in thermal sensitivity of jumping performance in the frog Limnodynastes peronii

2001 ◽  
Vol 204 (24) ◽  
pp. 4227-4236 ◽  
Author(s):  
Robbie S. Wilson
Keyword(s):  
Geographic Variation ◽  
Thermal Sensitivity ◽  
Geographic Range ◽  
The Body ◽  
Jumping Performance ◽  
Thermal Environments ◽  
Jump Distance ◽  
Sensitivity Curves ◽  
Cool Temperate ◽  
Different Populations

SUMMARY I compared the thermal sensitivity of jumping performance of five populations of the striped marsh frog (Limnodynastes peronii) over a wide geographic range extending from the cool-temperate south to the tropical north of Australia. Maximum jumping performance of adult L. peronii was assessed for each population at eight temperatures between 5°C and 32°C using a custom-designed force platform. From force recordings for each individual jump, maximum jumping force (Fmax) and acceleration (Amax) and maximum power output (Pmax), take-off velocity (Umax), jump distance (DJ) and contact time on the platform (TC) were calculated. The body mass of adult L. peronii varied over their geographic range, from approximately 5 g for the lowland tropical population to more than 22 g for the cool-temperate populations. The thermal sensitivity of jumping performance varied over their geographic range, with the populations from the cooler climates generally performing better than those from the warmer climate populations at the cooler temperatures, and vice versa at the higher temperatures. However, not all parameters of jumping performance underwent parallel changes in thermal sensitivity amongst the populations of L. peronii. Only minor differences in the shape of the thermal sensitivity curves for Fmax and Amax were detected amongst the populations, while the thermal sensitivities of Umax, DJ and Pmax all displayed considerable variation amongst the populations. The optimal temperatures for Umax, DJ and Pmax were generally lower in the cool-temperate populations than in the tropical populations of L. peronii. To determine whether this geographic variation was due to genetic variation, or merely reflected phenotypic plasticity, I also compared the thermal sensitivity of jumping performance between metamorph L. peronii from two different populations raised under identical conditions in the laboratory. The maximum jumping distance of the metamorph L. peronii was assessed at seven temperatures between 8°C and 35°C for the two latitudinally extreme populations (i.e. lowland tropical Proserpine and cool-temperate Gippsland populations). Like adult L. peronii, the metamorphs from the cool-temperate population jumped further than those from the lowland tropical population at the lower temperatures, although no differences were detected at the higher temperatures. Thus, geographic variation in thermal sensitivity of jumping performance in L. peronii probably has a genetic component, and the different populations appear to have undergone genetic adaptation of their thermal sensitivity to the varied thermal environments.

Dealing with hot rocky environments: Critical thermal maxima and locomotor performance in Leptodactylus lithonaetes (Anura: Leptodactylidae)

2019 ◽  
pp. 155-161 ◽  
Author(s):  
Ivan Beltran
Keyword(s):  
Environmental Temperature ◽  
Extreme Temperature ◽  
Effect Of Temperature ◽  
Maximum Speed ◽  
Locomotor Performance ◽  
Extreme Temperatures ◽  
Physiological Limits ◽  
Fitness Consequences ◽  
Thermal Maximum ◽  
Environmental Temperatures

Environmental temperature has fitness consequences on ectotherm development, ecology and behaviour. Amphibians are especially vulnerable because thermoregulation often trades with appropriate water balance. Although substantial research has evaluated the effect of temperature in amphibian locomotion and physiological limits, there is little information about amphibians living under extreme temperature conditions. Leptodactylus lithonaetes is a frog allegedly specialised to forage and breed on dark granitic outcrops and associated puddles, which reach environmental temperatures well above 40 ˚C. Adults can select thermally favourable microhabitats during the day while tadpoles are constrained to rock puddles and associated temperature fluctuations; we thus established microhabitat temperatures and tested whether the critical thermal maximum (CTmax) of L. lithonaetes is higher in tadpoles compared to adults. In addition, we evaluated the effect of water temperature on locomotor performance of tadpoles. Contrary to our expectations, puddle temperatures were comparable and even lower than those temperatures measured in the microhabitats used by adults in the daytime. Nonetheless, the CTmax was 42.3 ˚C for tadpoles and 39.7 ˚C for adults. Regarding locomotor performance, maximum speed and maximum distance travelled by tadpoles peaked around 34 ˚C, approximately 1 ˚C below the maximum puddle temperatures registered in the puddles. In conclusion, L. lithonaetes tadpoles have a higher CTmax compared to adults, suggesting a longer exposure to extreme temperatures that lead to maintain their physiological performance at high temperatures. We suggest that these conditions are adaptations to face the strong selection forces driven by this granitic habitat.

Vulnerability to global warming of a Critically Endangered lizard from the Monte Desert, Patagonia Argentina

2021 ◽  
Author(s):  
María Victoria Brizio ◽  
Facundo Cabezas-Cartes ◽  
Jimena Beatriz Fernández ◽  
Rodrigo Gómez Alés ◽  
Luciano Javier Avila
Keyword(s):  
Global Warming ◽  
Thermal Sensitivity ◽  
Thermal Conditions ◽  
Sun Exposure ◽  
Critically Endangered ◽  
Body Temperatures ◽  
Monte Desert ◽  
Safety Margins ◽  
Environmental Temperatures

Reptiles’ body temperature is strongly influenced by the thermal quality of microhabitats, exploiting the favourable environmental temperatures, and avoiding exposure to extreme thermal conditions. For these reasons, reptiles’ populations are considered to be especially vulnerable to changes in environmental temperatures produced by climate change. Here, we study the thermal physiology of the Critically Endangered lizard Liolaemus cuyumhue Avila, Morando, Perez and Sites, 2009. We hypothesise that, (1) there is a thermal coadaptation between optimal temperature for locomotor performance of L. cuyumhue and its thermal preference; (2) L. cuyumhue lives in an environment with low thermal quality; (3) a raise in environmental temperatures due to global warming will impose a decrement in locomotor speed represented by lower warming tolerance and narrower thermal safety margins, increasing their already high vulnerability. We registered field body temperatures (Tb), preferred body temperatures (Tpref), the operative (Te), and the thermal sensitivity of locomotion at different body temperatures. Our results indicate that this lizard is not currently under environmental stress or exceeding its thermal limits, but that it is thermorregulating below Tpref to avoid overheating, and that an increase in environmental temperature higher than 3.5 °C will strongly affect the use of microhabitats with direct sun exposure.

scholarly journals Modeling and thermodynamic properties of ‘bacaba’ pulp drying

2019 ◽  
Vol 23 (9) ◽  
pp. 702-708 ◽  
Author(s):  
Maria F. de Morais ◽  
José R. O. dos Santos ◽  
Marisângela P. dos Santos ◽  
Dyego da C. Santos ◽  
Tiago N. da Costa ◽  
...  
Keyword(s):  
Activation Energy ◽  
Thermodynamic Properties ◽  
Diffusion Coefficients ◽  
Effective Diffusion ◽  
Thermal Conditions ◽  
Drying Process ◽  
Experimental Conditions ◽  
Effective Diffusion Coefficients ◽  
Drying Rates ◽  
Increasing Temperature

ABSTRACT This study aimed to dry ‘bacaba’ (Oenocarpus bacaba Mart.) pulp under different thermal conditions, fit different mathematical models to the dehydration curves, and calculate the diffusion coefficients, activation energy and thermodynamic properties of the process. ‘Bacaba’ fruits were meshed to obtain the pulp, which was dried at temperatures of 40, 50 and 60 °C and with thickness of 1.0 cm. Increase in drying temperature reduced the dehydration times, as well as the equilibrium moisture contents, and drying rates of 0.65, 1.04 and 1.25 kg kg min-1 were recorded at the beginning of the process for temperatures of 40, 50 and 60 °C, respectively. The Midilli’s equation was selected as the most appropriate to predict the drying phenomenon, showing the highest R2, lowest values of mean square deviation (MSD) and χ2 under most thermal conditions, and random distribution of residuals under all experimental conditions. The effective diffusion coefficients increased with increasing temperature, with magnitudes of the order of 10-9 m2 s-1, being satisfactorily described by the Arrhenius equation, which showed activation energy (Ea) of 37.01 kJ mol-1. The drying process was characterized as endergonic, in which enthalpy (ΔH) and entropy (ΔS) reduced with the increment of temperature, while Gibbs free energy (ΔG) was increased.

Computer System Response Time and Psychophysiological Stress II

1982 ◽  
Vol 26 (8) ◽  
pp. 698-702 ◽  
Author(s):  
Stuart Martin Weiss ◽  
George Boggs ◽  
Mark Lehto ◽  
Sogand Shodja ◽  
David J. Martin
Keyword(s):  
Response Time ◽  
Repeated Measures ◽  
Psychological Impact ◽  
Industrial Process ◽  
Interactive Systems ◽  
Upper And Lower Bounds ◽  
System Response ◽  
User Performance ◽  
Experimental Conditions ◽  
System Response Time

With the advent of time-shared interactive systems, the psychological impact of system response time (SRT) and SRT variability (SRTV) has become an important issue. Carbonell, et. al. (1968) have suggested that both SRT and SRTV may influence system user performance and satisfaction. A number of studies have been reported that address this issue, but results have been mixed. In this experiment, twenty subjects ( Ss) executed keyboard entries to control the temperature of a simulated industrial process via time-shared process control computer. Temperature was displayed in analog form on a CRT. The task was to maintain the temperature within upper and lower bounds that were clearly indicated on the display. The experimental design consisted of repeated measures with SRT and SRTV as experimental factors. Three SRT's were employed (2, 6 and 10 seconds) with two levels of SRTV (σ2 = 0 and σ2 = 0.33 seconds). Mean blood pressure (MBP) and heart rate (HR) were continuously monitored during experimental conditions. Task errors were defined as temperature excursions beyond the displayed bounds. Significant main effects were not obtained for MBP or HR. Significant differences for error rate (performance) were noted for SRT ( F(2, 15) = 23.10, p < .05), subjects x SRT ( F37, 15) = 1.66, p < .001), and SRT x SRTV ( F(1, 15) = 13.14, p < .05). Error data are consistent with the Carbonell et. al. suggestion that long and variable SRT may affect user performance. The results are discussed in terms of their incongruity with current literature.

Storage of DMFC MEA at Extreme Temperatures

2008 ◽  
Author(s):  
Ulrike Krewer ◽  
Junyoung Park ◽  
Jinhwa Lee ◽  
Hyejung Cho
Keyword(s):  
Reverse Current ◽  
Catalyst Loading ◽  
Membrane Electrode ◽  
Extreme Temperatures ◽  
Original Performance ◽  
Experimental Conditions ◽  
Low Temperature Storage ◽  
Electrode Assemblies ◽  
Negative Effect ◽  
Temperature Storage

This paper investigates the change in performance of DMFC membrane electrode assemblies (MEAs) after storage at −10°C and 60°C under different experimental conditions. It highlights the importance of methanol concentration, an MEA’s material properties such as membrane material and catalyst loading, as well as the reactivation procedure. Storage at 60°C and concentrations below 1M methanol had no negative effect on MEA performance while storage at 60°C in a 4 M methanol solution could cause a severe performance decrease. Application of a reverse current for 10 s to a MEA which was affected by such storage was found to reinstall original performance. The effect of storage at −10°C on MEA performance strongly depends on MEA properties. MEAs are grouped into three different categories with regard to suitability for low temperature storage: not affected, reversibly affected, and irreversibly affected. The reversibly affected MEAs could be instantly and completely reactivated by reverse current. MEA materials such as various hydrocarbon membranes and high catalyst loadings as well as the manufacturing methods CCM (catalyst coated on the membrane) and CCS (catalyst coated on the substrate) were found to be principally suitable to build MEAs tolerant to storage at −10° C.

A Needlelike Probe for Temperature Monitoring During Laser Ablation Based on Fiber Bragg Grating: Manufacturing and Characterization

2015 ◽  
Vol 9 (4) ◽  
Author(s):  
Davide Polito ◽  
Michele Arturo Caponero ◽  
Andrea Polimadei ◽  
Paola Saccomandi ◽  
Carlo Massaroni ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Measurement Error ◽  
Response Time ◽  
Fiber Bragg Grating ◽  
Thermal Sensitivity ◽  
Temperature Monitoring ◽  
Respiratory Pattern ◽  
Bragg Grating ◽  
Thermal Paste ◽  
Fbg Sensors

Temperature distribution monitoring in tissue undergoing laser ablation (LA) could be beneficial for improving treatment outcomes. Among several thermometric techniques employed in LA, fiber Bragg grating (FBG) sensors show valuable characteristics, although their sensitivity to strain entails measurement error for patient respiratory movements. Our work describes a solution to overcome this issue by housing an FBG in a surgical needle. The metrological properties of the probes were assessed in terms of thermal sensitivity (0.027 nm °C−1 versus 0.010 nm °C−1 for epoxy liquid encapsulated probe and thermal paste one, respectively) and response time (about 100 ms) and compared with properties of nonencapsulated FBG (sensitivity of 0.010 nm °C−1, response time of 43 ms). The error due to the strain caused by liver movements, simulating a typical respiratory pattern, was assessed: the strain induces a probes output error less than 0.5 °C, which is negligible when compared to the response of nonencapsulated FBG (2.5 °C). The metallic needle entails a measurement error, called artifact, due to direct absorption of the laser radiation. The analysis of the artifact was performed by employing the probes for temperature monitoring on liver undergoing LA. Experiments were performed at two laser powers (i.e., 2 W and 4 W) and at nine distances between the probes and the laser applicator. The artifact decreases with the distance and increases with the power: it exceeds 10 °C at 4 W, when the encapsulated probes are placed at 3.6 mm and 0 deg from the applicator, and it is lower than 1 °C for distance higher than 5 mm and angle higher than 30 deg.

Thermal dependence of food assimilation and locomotor performance in juvenile blue-tailed skinks, Eumeces elegans

2007 ◽  
Vol 57 (1) ◽  
pp. 29-38 ◽  
Author(s):  
Yi-Xin Bao ◽  
Wei-Guo Du ◽  
Lin Shu ◽  
Yi-Wei Lu
Keyword(s):  
Food Intake ◽  
Thermal Sensitivity ◽  
Eastern China ◽  
Assimilation Efficiency ◽  
Age Difference ◽  
Locomotor Performance ◽  
Thermal Dependence ◽  
Physiological Performance ◽  
Effects Of Temperature ◽  
Food Assimilation

AbstractVariation in the physiological performance and behaviour of ectotherms as a result of changes in body temperature can affect important life-history traits. Studies investigating the effects of temperature on physiological performance and behaviour have thus clear ecological significance. We captured juvenile blue-tailed skinks, Eumeces elegans, from a population in Zhejiang, eastern China, and determined the effects of temperature on their food assimilation and locomotor performance. Food intake of the juveniles generally increased with increase in temperatures within the range of 24-30°C and decreased at higher temperatures. The temperature significantly affected the apparent digestive coefficient (ADC) and the assimilation efficiency (AE) of juveniles; the ADC and AE of the skinks at 32°C were higher than those of skinks at other temperatures. The sprint speed increased with increase in temperature within the range of 12-32°C and decreased at higher temperatures. These results suggest the patterns of thermal sensitivity may differ in various functional performances, and hence support the 'multiple optima hypothesis', which suggests that no specific temperature maximises all functional performance. In addition, this study indicates significant between-age difference in thermal physiology by comparing our data with those on adult skinks, including different thermal sensitivity of AE, and different ranges of thermal-performance breadth for food intake and locomotor performance between juvenile and adult E. elegans.

Response Time to the Second of Two Successive Signals as a Function of Absolute and Relative Duration of Intersignal Interval

1965 ◽  
Vol 21 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Raymond S. Nickerson
Keyword(s):  
Response Time ◽  
Refractory Period ◽  
Psychological Refractory Period ◽  
Relative Duration ◽  
Experimental Conditions ◽  
Variable Duration ◽  
The Absolute

An experiment was conducted to determine whether both the absolute and the relative duration of the S1-S2 interval would affect the response time to the second of two successive signals (RT2) separated by an interval of brief but variable duration. Four different experimental conditions sampled different but overlapping ranges of intervals, thus allowing comparisons between RTs obtained with intervals of the same absolute but different relative durations, and conversely, with the same relative but different absolute durations. Under these conditions, RT2 varied inversely with both the absolute and the relative duration of interval over the range of intervals generally associated with psychological refractory period.

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