scholarly journals A widespread thermodynamic effect, but maintenance of biological rates through space across life’s major domains

2018 ◽  
Author(s):  
Jesper G. Sørensen ◽  
Craig R. White ◽  
Grant A. Duffy ◽  
Steven L. Chown
Keyword(s):  
Temperature Compensation ◽  
Large Scale ◽  
Positive Relationship ◽  
Environmental Temperature ◽  
Physiological Adaptation ◽  
Thermal Environments ◽  
Maximal Performance ◽  
Thermodynamic Effect ◽  
Performance Rate ◽  
Alternative Idea

AbstractFor over a century, temperature compensation (maintenance of biological rates with changing temperatures) has remained controversial. An alternative idea, that fitness is greater at higher temperatures (the thermodynamic effect), has gained increasing traction, and is being used to understand large-scale biodiversity responses to environmental change. Yet evidence in favour of each of these contrasting hypotheses continues to emerge. In consequence, the fundamental nature of organismal thermal responses and its implications remain unresolved. Here we investigate these ideas explicitly using a global dataset of 619 observations of four categories of organismal performance, spanning 14 phyla and 403 species. In agreement with both hypotheses, we show a positive relationship between the temperature of maximal performance rate (Topt) and environmental temperature (Tenv) for all traits. Next we demonstrate that relationships between Tenvand the temperature of maximal performance rate (Umax) are rarely significant and positive, as expected if a thermodynamic effect predominates. By contrast, a positive relationship between Toptand Umaxis always present, but markedly weaker than theoretically predicted. These outcomes demonstrate that while some form of thermodynamic effect exists, ample scope is present for biochemical and physiological adaptation to thermal environments in the form of temperature compensation.

scholarly journals A widespread thermodynamic effect, but maintenance of biological rates through space across life's major domains

2018 ◽  
Vol 285 (1890) ◽  
pp. 20181775 ◽  
Author(s):  
Jesper G. Sørensen ◽  
Craig R. White ◽  
Grant A. Duffy ◽  
Steven L. Chown
Keyword(s):  
Temperature Compensation ◽  
Large Scale ◽  
Positive Relationship ◽  
Alternative Hypothesis ◽  
Developmental Rate ◽  
Physiological Adaptation ◽  
Thermal Environments ◽  
Maximal Performance ◽  
Thermodynamic Effect ◽  
Performance Rate

For over a century, the hypothesis of temperature compensation, the maintenance of similar biological rates in species from different thermal environments, has remained controversial. An alternative idea, that fitness is greater at higher temperatures (the thermodynamic effect), has gained increasing traction. This alternative hypothesis is also being used to understand large-scale biodiversity responses to environmental change. Yet evidence in favour of each of these contrasting hypotheses continues to emerge. In consequence, the fundamental nature of organismal thermal responses and its implications remain unresolved. Here, we investigate these ideas explicitly using a global dataset of 619 observations of four categories of organismal performance, spanning 14 phyla and 403 species. In agreement with both hypotheses, we show a positive relationship between the temperature of maximal performance rate ( T opt ) and environmental temperature ( T env ) for developmental rate and locomotion speed, but not growth or photosynthesis rate. Next, we demonstrate that relationships between T env and the maximal performance rate ( U max ) are rarely significant and positive, as expected if a thermodynamic effect predominates. By contrast, a positive relationship between T opt and U max is always present, but markedly weaker than theoretically predicted. These outcomes demonstrate that while some form of thermodynamic effect exists, ample scope is present for biochemical and physiological adaptation to thermal environments in the form of temperature compensation.

Design of Ultrasonic Ranging Circuit Based on STC Microcontroller

2013 ◽  
Vol 722 ◽  
pp. 59-63
Author(s):  
Rui Luo ◽  
Zi Hong Zhang
Keyword(s):  
System Performance ◽  
Temperature Compensation ◽  
Measurement Accuracy ◽  
Environmental Temperature ◽  
Detection Distance ◽  
Compensation Circuit ◽  
High Measurement ◽  
Ultrasonic Ranging ◽  
Allowable Range ◽  
Market Promotion

In this paper, based on the 18B20 temperature compensation circuit for ultrasonic ranging circuit, can eliminate the influence of environmental temperature on ultrasonic velocity, this paper introduced the ultrasonic ranging system, the system includes ultrasonic transmitting circuit, receiving circuit and display circuit, the results of the experiment show that, the system detection distance can be up to 12M, the error is in the allowable range, the range finder the system performance is stable, high measurement accuracy, distance, has a certain practicality and market promotion value.

scholarly journals On the Energy Efficiency of Indoor Air Conditioning

2019 ◽  
Vol 62 (4) ◽  
pp. 325-340 ◽  
Author(s):  
S. N. Osipov ◽  
A. V. Zakharenko ◽  
E. M. Shirokova
Keyword(s):  
Energy Efficiency ◽  
Heat Exchange ◽  
Indoor Air ◽  
Air Conditioning ◽  
Large Scale ◽  
Well Being ◽  
Physiological Adaptation ◽  
Limited Area ◽  
Air Conditioner ◽  
Conditioning Process

The increase of average outdoor temperatures and their fluctuations over the past 20 years (as evidenced by the records of summer temperatures in our country) has significantly increased the need for air conditioning premises where people are present for a long time, especially when they are crowded (shops, entertainment halls, classrooms, etc.). The air conditioning process is quite energy-intensive, but the growth of well-being in many republics of the former USSR, as well as the increasing complexity of the physiological adaptation of the human body to rising outdoor temperatures make it possible (and at the same time necessary) to implement these systems on a large scale. It is important to take into account that electricity prices are currently maintained at a high level for homeowners, and in the coming years the prices will only grow. Therefore, the development of new ways of significant increase of the energy efficiency of the indoor air conditioning process is of a great interest. One of these methods is the use of laminar (or close to them) moving layers of conditioned air in a limited area of work or rest of people. Such a zone, about 1.0‒1.2 m height from a floor in each apartment is, e.g., living rooms (bedroom) in which standard temperature conditions are created by means of simple air supplying and air intake devices. In the case of sedentary work of people, the height of such a zone of conditioned air should be increased to 1.3‒1.5 m. It has already been established that the use of laminar (or close to them) air flows allows to reduce the power consumption by two or more times due to significantly reduced heat exchange with the surrounding heated surfaces. Besides, the simplicity of such systems ought to be noted. In particular, in conditions of modern systems of control and management of air conditioning, the "duties" of consumers include only the installation on the control device of the initial data relating directly to the required parameters of the microclimate. At the same time, it should be noted that there is currently no complete scientific and technical description of aerodynamic and heat exchange processes in the air conditioning zone. Even in modern conditions for countries with a sharply continental climate (Russia, Kazakhstan, etc.), the problem is the choice of the type of air conditioner for its effective use in hot periods of summer. In general, it can be noted that all the problems of energy-efficient use of air conditioners must find a comprehensive solution.

Do microbial communities adapt to the temperature of their climate?

2020 ◽  
Author(s):  
Daniel Tajmel ◽  
Carla Cruz Paredes ◽  
Johannes Rousk
Keyword(s):  
Environmental Factors ◽  
Microbial Communities ◽  
Large Scale ◽  
Microbial Growth ◽  
Environmental Temperature ◽  
Microbial Processes ◽  
Temperature Relationship ◽  
Maximum Temperature ◽  
Mean Annual Temperature ◽  
The Impact

<p>Terrestrial biogeochemical cycles are regulated by soil microorganisms. The microbial carbon release due to respiration and carbon sequestration through microbial growth determine whether soils become sources or sinks for carbon. Temperature i​s one of the most important environmental factors controlling both microbial growth and respiration. Therefore, to understand the influence of temperature on microbial processes is crucial. One strategy to predict how ecosystems will respond to warming is to use geographical ecosystem differences, in space-for-time (SFT) substitution approaches. We hypothesized (1) that microbes should be adapted to their environmental temperature leading to microbial communities with warm-shifted temperature relationships in warmer environments, and vice versa. Furthermore, we hypothesized  (2) that other factors should not influence microbial temperature relationships, and (3) that the temperature sensitivity of microbial processes (Q10) should be linked to the microbial temperature relationships.</p><p> </p><p>In this project, we investigated the effects of environmental temperature on microbial temperature relationships for microbial growth and respiration along a natural climate gradient along a transect across Europe to predict the impact of a warming climate. The transect was characterized by mean annual temperature (MAT) ranging from - 4 degrees Celsius (Greenland) to 18 degrees Celsius (Southern Spain), while other environmental factor ranges were broad and unrelated to climate, including pH from 4.0 to 8.8, C/N ratio from 7 to 50, SOM from 4% to 94% and plant communities ranging from arctic tundra to Mediterranean grasslands. More than 56 soil samples were analyzed and microbial temperature relationships were determined using controlled short-term laboratory incubations from 0 degrees Celsius to 45 degrees Celsius. The link between microbial temperature relationship and the climate was assessed by using the relationship between the environmental temperature and indices for microbial temperature relationships including the minimum (T<sub>min</sub>), optimum (T<sub>opt</sub>) and maximum temperature (T<sub>max</sub>) for microbial growth as well as for respiration. To estimate the T<sub>min</sub>, T<sub>opt </sub>and T<sub>max </sub>the square root equation, the Ratkowsky model was used.</p><p> </p><p>We found that microbial communities were adapted to their environmental temperature. The microbial temperature relationship was stronger for microbial growth than for respiration. For 1 degrees Celsius rise in MAT, T<sub>min </sub>increased 0.22 degrees Celsius for bacterial and 0.28 degrees Celsius for fungal growth, while T<sub>min </sub>for respiration increased by 0.16 per 1 degrees Celsius rise. T<sub>min </sub>was also found to be universally linked to Q10, such that higher T<sub>min </sub>resulted in higher Q10. Other environmental factors (pH, C/N ratio, SOM, vegetation cover) did not influence the temperature relationships. By incorporating the determined relationships between environmental temperature and microbial growth and respiration into large scale ecosystem models, we can get a better understanding of the influence of microbial adaptation to warmer climate on the C-exchange between soils and atmosphere.</p>

scholarly journals More individuals but fewer species: testing the ‘more individuals hypothesis’ in a diverse tropical fauna

2010 ◽  
Vol 6 (4) ◽  
pp. 490-493 ◽  
Author(s):  
Terrence P. McGlynn ◽  
Michael D. Weiser ◽  
Robert R. Dunn
Keyword(s):  
Species Richness ◽  
Primary Productivity ◽  
Large Scale ◽  
Positive Relationship ◽  
Tropical Rainforest ◽  
Net Primary Productivity ◽  
Resource Abundance ◽  
Monotonic Increase ◽  
Ant Diversity ◽  
Unimodal Relationship

A positive relationship between species richness and productivity is often observed in nature, but the causes remain contentious. One mechanism, the ‘more individuals hypothesis’ (MIH), predicts richness increases monotonically with density, as a function of resource flux. To test the MIH, we manipulated resource abundance in a community of tropical rainforest litter ants and measured richness and density responses. A unimodal relationship between richness and density most closely fitted the control and disturbance (resource removal) treatments in contrast to expectations of the MIH. Resource addition resulted in a monotonic increase in richness relative to density, a shift from the pattern in the control. In the disturbance treatment, richness was greater than in the control, opposite to expectations of the MIH. While large-scale correlations between ant diversity and net primary productivity or temperature are reconcilable with the MIH, key elements of the hypothesis are not supported.

scholarly journals Evaluating the large-scale hydrological cycle response within the PlioMIP2 ensemble

2021 ◽  
Author(s):  
Zixuan Han ◽  
Qiong Zhang ◽  
Qiang Li ◽  
Ran Feng ◽  
Alan M. Haywood ◽  
...  
Keyword(s):  
Large Scale ◽  
Hydrological Cycle ◽  
Atmospheric Transport ◽  
Hadley Circulation ◽  
Dynamic Effect ◽  
Walker Circulation ◽  
Future Climate Change ◽  
Atmospheric Energy ◽  
Budget Analysis ◽  
Thermodynamic Effect

Abstract. The mid-Pliocene (~ 3 million years ago) is one of the most recent warm periods with high CO2 concentrations in the atmosphere and resulting high temperatures and is often cited as an analog for near-term future climate change. Here, we apply a moisture budget analysis to investigate the response of the large-scale hydrological cycle at low latitudes within a 13-model ensemble from the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2). The results show that increased atmospheric moisture content within the mid-Pliocene ensemble (the thermodynamic effect) results in wetter conditions over the deep tropics, i.e., the Pacific intertropical convergence zone (ITCZ) and the Maritime Continent, and drier conditions over the subtropics. The thermodynamic effect is to some extent offset by a dynamic effect involving a northward shift of the Hadley circulation that dries the deep tropics and moistens the subtropics in the Northern Hemisphere (i.e., the subtropical Pacific). From the perspective of Earth’s energy budget, the enhanced southward cross-equatorial atmospheric transport (0.22 PW), induced by the hemispheric asymmetries of the atmospheric energy, favors an approximately 1° northward shift of the ITCZ. The shift of the ITCZ reorganizes atmospheric circulation, favoring a northward shift of the Hadley circulation. In addition, the Walker circulation consistently shifts westward within PlioMIP2 models, leading to wetter conditions over the northern Indian Ocean. The PlioMIP2 ensemble highlights that an imbalance of interhemispheric atmospheric energy during the mid-Pliocene could have led to changes in the dynamic effect, offsetting the thermodynamic effect and hence altering mid-Pliocene hydroclimate cycling.

scholarly journals The Role of Knowledge Adoptive Capacity towards Exports Performance

2019 ◽  
Vol 2 (5) ◽  
pp. 62-71
Author(s):  
Ramaisa Aqdas ◽  
Nik Ab Halim Nik Abdullah
Keyword(s):  
Absorptive Capacity ◽  
Quantitative Data ◽  
Design Methodology ◽  
Large Scale ◽  
Positive Relationship ◽  
Export Performance ◽  
Dynamic Capability ◽  
Significant Positive Relationship ◽  
Knowledge Based

Purpose - Knowledge absorptive capacity plays a significant role in export performance. It is a dynamic capability that firms apply to gain competitiveness in today’s knowledge-based economies. The aim of the present research is to identify relationship among dimensions of KAC and export performance. Design/Methodology - Nature of study was descriptive and quantitative. Data was collected through questionnaires from 291 large scale textile firms of Pakistan. Smart PLS was used in analyzing data by incorporating CFA and SEM techniques to test the hypotheses. Findings - The results reveal that knowledge acquisition, transformation, and exploitation have significant positive relationship with export performance.

Temperature Independent Fluidic Resistive Circuits and Concepts

1984 ◽  
Vol 106 (1) ◽  
pp. 98-101
Author(s):  
T. M. Drzewiecki
Keyword(s):  
Laminar Flow ◽  
Temperature Sensitivity ◽  
Temperature Compensation ◽  
Environmental Temperature ◽  
Working Fluid ◽  
Fluidic Devices ◽  
Constant Resistance ◽  
Pressure Controlled ◽  
The Way

This paper discusses series and parallel topologies of orifices and capillaries as fluidic resistors and the way that they relate to temperature sensitivity and temperature compensation. Examination of a laminar flow nozzle, as typically found in a laminar proportional amplifier (LPA), shows that it may be represented by a parallel combination of an orifice and a capillary. As a result a nozzle has inherent temperature insensitive properties that allow temperature independent operation of such laminar fluidic devices as pressure controlled oscillators. It is shown that one may design a constant resistance, within ±0.1 percent, for changes in environmental temperature of ±20°C when air is the working fluid.

scholarly journals Evolutionary stasis and lability in thermal physiology in a group of tropical lizards

2014 ◽  
Vol 281 (1778) ◽  
pp. 20132433 ◽  
Author(s):  
Martha M. Muñoz ◽  
Maureen A. Stimola ◽  
Adam C. Algar ◽  
Asa Conover ◽  
Anthony J. Rodriguez ◽  
...  
Keyword(s):  
Cold Tolerance ◽  
Heat Tolerance ◽  
Climate Warming ◽  
Physiological Traits ◽  
Physiological Adaptation ◽  
Night Time ◽  
Thermal Environments ◽  
Evolutionary Response ◽  
Lower Temperature ◽  
Similar Body

Understanding how quickly physiological traits evolve is a topic of great interest, particularly in the context of how organisms can adapt in response to climate warming. Adjustment to novel thermal habitats may occur either through behavioural adjustments, physiological adaptation or both. Here, we test whether rates of evolution differ among physiological traits in the cybotoids, a clade of tropical Anolis lizards distributed in markedly different thermal environments on the Caribbean island of Hispaniola. We find that cold tolerance evolves considerably faster than heat tolerance, a difference that results because behavioural thermoregulation more effectively shields these organisms from selection on upper than lower temperature tolerances. Specifically, because lizards in very different environments behaviourally thermoregulate during the day to similar body temperatures, divergent selection on body temperature and heat tolerance is precluded, whereas night-time temperatures can only be partially buffered by behaviour, thereby exposing organisms to selection on cold tolerance. We discuss how exposure to selection on physiology influences divergence among tropical organisms and its implications for adaptive evolutionary response to climate warming.

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