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.

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 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.

scholarly journals Capuchin monkey rituals: an interdisciplinary study of form and function

2020 ◽  
Vol 375 (1805) ◽  
pp. 20190422 ◽  
Author(s):  
Susan Perry ◽  
Marco Smolla
Keyword(s):  
Alternative Hypothesis ◽  
Capuchin Monkey ◽  
Ritual Performance ◽  
Form And Function ◽  
Sacred Objects ◽  
And Function ◽  
Opening And Closing ◽  
Performance Rate ◽  
Interdisciplinary Study ◽  
Behavioural Repertoire

Many white-faced capuchin monkey dyads in Lomas Barbudal, Costa Rica, practise idiosyncratic interaction sequences that are not part of the species-typical behavioural repertoire. These interactions often include uncomfortable or risky elements. These interactions exhibit the following characteristics commonly featured in definitions of rituals in humans: (i) they involve an unusual intensity of focus on the partner, (ii) the behaviours have no immediate utilitarian purpose, (iii) they sometimes involve ‘sacred objects’, (iv) the distribution of these behaviours suggests that they are invented and spread via social learning, and (v) many behaviours in these rituals are repurposed from other behavioural domains (e.g. extractive foraging). However, in contrast with some definitions of ritual, capuchin rituals are not overly rigid in their form, nor do the sequences have specific opening and closing actions. In our 9260 h of observation, ritual performance rate was uncorrelated with amount of time dyads spent in proximity but (modestly) associated with higher relationship quality and rate of coalition formation across dyads. Our results suggest that capuchin rituals serve a bond-testing rather than a bond-strengthening function. Ritual interactions are exclusively dyadic, and between-dyad consistency in form is low, casting doubt on the alternative hypothesis that they enhance group-wide solidarity. This article is part of the theme issue ‘Ritual renaissance: new insights into the most human of behaviours’.

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.

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.

Influence of Impeller Fairing Cone Geometry on Cavitating Flow Behavior in a Cryogenic Liquid Turbine Expander

2016 ◽  
Author(s):  
Ke Wang ◽  
Jinju Sun ◽  
Peng Song ◽  
Changjiang Huo
Keyword(s):  
Large Scale ◽  
Bubble Dynamics ◽  
Flow Behavior ◽  
Hydraulic Turbine ◽  
Sensitivity Study ◽  
Cryogenic Liquid ◽  
Cavitating Flow ◽  
Air Separation ◽  
Separation Unit ◽  
Thermodynamic Effect

A single stage cryogenic liquid turbine expander is developed as a replacement for traditional Joule-Thomson valves used in the large-scale internal compression air-separation unit for the purpose of energy saving. Similar to the conventional hydraulic turbine, detrimental swirling and cavitation flow is also encountered at turbine expander impeller exit and its successive diffuser tube, but due to significant thermodynamic effect of cryogenic fluid flow, it is much more complicated than the conventional hydraulic turbine. In the present study, cavitating flow mechanism of the turbine expander is investigated first with a combination of the homogenous multiphase mixture model and the Rayleigh-Plesset model, where the former treats liquid and gas as a continuum mixture and the latter depicts the bubble dynamics. Then sensitivity study is conducted for the impeller fairing cone geometry on suppression of cavitating flow. The following are demonstrated: with a use of the fairing cone, flow behavior near and downstream the impeller exit is significantly improved, where the low static pressure region is reduced and the local temperature rise decreases, subsequently the cavitating flow is effectively suppressed. The cavitating flow is sensitive to a tuning of the fairing cone geometry, and an optimal design of the cone geometry is essential.

scholarly journals Maximizing Ecosystem Services Provided to the New Oil Crop Brassica carinata Through Landscape and Arthropod Diversity

2019 ◽  
Author(s):  
Shane Stiles ◽  
Jon Lundgren ◽  
Charles Fenster ◽  
Henning Nottebrock
Keyword(s):  
Ecosystem Services ◽  
Crop Yield ◽  
Seed Treatment ◽  
Large Scale ◽  
Positive Relationship ◽  
Landscape Heterogeneity ◽  
Insect Diversity ◽  
Farming Practices ◽  
Pollinator Diversity ◽  
The Relationship

ABSTRACTPrairies, once spanning the Upper Midwest, have now largely been replaced by agriculture. The lack of resources available to pollinators in agricultural fields and practices commonly employed has led to a decline in insect diversity. To enhance sustainable practices, we must better understand how ecosystem services such as pest control and pollination services provided by a diverse insect and pollinator community scale to current farming practices as related to crop yield and how landscape features may positively contribute to insect and pollinator diversity. We examined how landscape heterogeneity relates to insect and pollinator diversity, as well as how insect and pollinator diversity relates to crop yield across common farming practices. We planted 35 single acre sites of Brassica carinata, a generalist flower possibly capable of supporting a diverse insect community. We randomly assigned each site with a combination of three common farming practices: tilling (yes/no), added honey bee hives (yes/no), and treatment with systemic neonicotinoids (yes/no). Insect and pollinator diversity and the surrounding landscape at multiple spatial scales were calculated. We observed a significant positive relationship between insect (and pollinator) diversity with yield in the absence of any farming practice. All farming practices will increase yield. However, farming practices alter the relationship between yield and diversity. The addition of seed treatment or tillage negates the relationship between insect (and pollinator) diversity with yield. Seed treatment alone results in a flat relationship between diversity and yield for all insects and a negative relationship for pollinators. Increased landscape heterogeneity results in a positive relationship between insect diversity at the 1000 m scale and pollinator diversity at the 3000 m scale, suggesting large-scale heterogeneity contributes to overall insect diversity. Our results show that increasing large-scale landscape heterogeneity increases diversity serving as a substitute for common farming practices such as application of pesticides, tilling, or bee hives. Increased heterogeneity could save farmers from the input cost of treatment or tillage, by way of increased insect diversity, while still providing similar yields.

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