Rate Of Energy Use Research Articles

Thermal and morphometric correlates of the extremely low rate of energy use in a wild frugivorous primate, the Mayotte lemur

Primates spend on average half as much energy as other placental mammals while expressing a wide range of lifestyles. However, little is known about how primates adapt their rate of energy use in the context of natural environmental variations. Using doubly labelled water, behavioral and accelerometric methods, we measured the total energy expenditure (TEE) and body composition of a population of Eulemur fulvus (N = 12) living in an agroforest in Mayotte. We show that the TEE of this medium-sized cathemeral primate is one of the lowest recorded to date in eutherians. Regression models show that individual variation in the rate of energy use is predicted by fat-free mass, body size, thigh thickness and maximum temperature. TEE is positively correlated with increasing temperature, suggesting that thermoregulation is an important component of the energy budget of this frugivorous species. Mass-specific TEE is only 10% lower than that of a closely related species previously studied in a gallery forest, consistent with the assertion that TEE varies within narrow physiological limits. As lemur communities include many species with unique thermoregulatory adaptations, circadian and/or seasonal temperature variations may have constituted a major selective pressure on the evolution of lemur metabolic strategies.

Metabolic plasticity drives mismatches in physiological traits between prey and predator

Metabolic rate, the rate of energy use, underpins key ecological traits of organisms, from development and locomotion to interaction rates between individuals. In a warming world, the temperature-dependence of metabolic rate is anticipated to shift predator-prey dynamics. Yet, there is little real-world evidence on the effects of warming on trophic interactions. We measured the respiration rates of aquatic larvae of three insect species from populations experiencing a natural temperature gradient in a large-scale mesocosm experiment. Using a mechanistic model we predicted the effects of warming on these taxa’s predator-prey interaction rates. We found that species-specific differences in metabolic plasticity lead to mismatches in the temperature-dependence of their relative velocities, resulting in altered predator-prey interaction rates. This study underscores the role of metabolic plasticity at the species level in modifying trophic interactions and proposes a mechanistic modelling approach that allows an efficient, high-throughput estimation of climate change threats across species pairs.

Evaluating the Influences of Health Expenditure, Energy Consumption, and Environmental Pollution on Life Expectancy in Asia

This study examines the effects of health expenditure, energy consumption, CO2 emissions, population size, and income on health outcomes in 46 Asian nations between 1997 and 2019. Cross-sectional dependence (CSD) and slope heterogeneity (SH) tests are utilized due to the close linkages between Asian nations as a result of commerce, tourism, religion, and international agreements. The research uses unit root and cointegration tests of the second generation after validating CSD and SH issues. Due to the results of the CSD and SH tests, it is clear that conventional methods of estimation are inappropriate, so a new panel method, the inter autoregressive distributive lag (CS-ARDL) model, is used instead. In addition to CS-ARDL, the study's results were checked with a common correlated effects mean group (CCEMG) method and an augmented mean group (AMG) method. According to the CS-ARDL study, higher rates of energy use and healthcare spending lead to better health outcomes for Asian countries over the long run. CO2 emissions are shown to be harmful to human health, according to the study. The influence of a population's size on health outcomes is shown to be negative in the CS-ARDL and CCEMG, but favorable in the AMG. Only the AMG coefficient is significant. In most instances, the results of the AMG and CCEMG corroborate the results of the CS-ARDL. Among all the factors influencing life expectancy in Asian countries, healthcare spending is the most influential. Hence, to improve health outcomes, Asian countries need to take the required actions to boost health spending, energy consumption, and long-term economic growth. To achieve the best possible health outcomes, Asian countries should also reduce their CO2 emissions.

Energy Conservation and Energy Audit as an Energy Saving Effort at MSTP UNDIP (case study of MSTP Undip Jepara)

Conservation and energy saving audits on the consumer side are carried out to reduce the rate of energy use so that energy is not wasted. The MSTP Undip Jepara building was chosen as the object of the audit due to the absence of an energy audit report as a form of energy saving plan. Energy audits are carried out using the energy consumption intensity method to determine the efficiency level of the building based on the Minister of Energy and Mineral Resources Regulation No. 13 of 2012 and the significant energy users method to determine the distribution of energy consumption on installed equipment so that energy saving opportunities can be saved. Based on the calculation results, the MSTP Building is in the category of efficient energy consumption with the energy consumption intensity of air-conditioned and non air-conditioned buildings in 2021 with value 9.0 kWh/m2/month and 4.9 kWh/m2/month. Energy saving opportunities savings in the no/low cost category, the resulting savings are Rp. 31,963,190, medium cost Rp. 18,490,311, and high cost Rp. 582,503. Savings include setting air-conditioned temperature, reducing air-conditioned operating hours, replacing TL Neon and Spiral lamps with LEDs, as well as replacing conventional PCs with All-in-one PCs

Understanding energy use growth: The role of investment-GDP ratio

The aggregate analysis on the relationship between energy use and GDP growth may cloak important decision information. Among them, economic structure such as investment-GDP ratio is also vital to energy use. Employing a panel dataset of 64 large economies over 1972–2019, this study empirically investigates this issue. It finds that a higher ratio of investment to GDP is significantly associated with an increase in the growth rate of energy use, with an average effect size of 0.08. Two candidate mechanisms jointly contribute to such patterns: the growth of energy-intensive product and the changing ratio of industrial value added to GDP. The results show that economic structure transformation can help alleviate the pressure on energy demand.

Can Sex-Specific Metabolic Rates Provide Insight Into Patterns of Metabolic Scaling?

Females and males can exhibit striking differences in body size, relative trait size, physiology and behavior. As a consequence the sexes can have very different rates of whole-body energy use, or converge on similar rates through different physiological mechanisms. Yet many studies that measure the relationship between metabolic rate and body size only pay attention to a single sex (more often males), or do not distinguish between sexes. We present four reasons why explicit attention to energy-use between the sexes can yield insight into the physiological mechanisms that shape broader patterns of metabolic scaling in nature. First, the sexes often differ considerably in their relative investment in reproduction which shapes much of life-history and rates of energy use. Second, males and females share a majority of their genome but may experience different selective pressures. Sex-specific energy profiles can reveal how the energetic needs of individuals are met despite the challenge of within-species genetic constraints. Third, sexual selection often pushes growth and behavior to physiological extremes. Exaggerated sexually selected traits are often most prominent in one sex, can comprise up to 50% of body mass and thus provide opportunities to uncover energetic constraints of trait growth and maintenance. Finally, sex-differences in behavior such as mating-displays, long-distance dispersal and courtship can lead to drastically different energy allocation among the sexes; the physiology to support this behavior can shape patterns of metabolic scaling. The mechanisms underlying metabolic scaling in females, males and hermaphroditic animals can provide opportunities to develop testable predictions that enhance our understanding of energetic scaling patterns in nature.

Skeletal muscle and metabolic flexibility in response to changing energy demands in wild birds.

Phenotypically plastic responses of animals to adjust to environmental variation are pervasive. Reversible plasticity (i.e., phenotypic flexibility), where adult phenotypes can be reversibly altered according to prevailing environmental conditions, allow for better matching of phenotypes to the environment and can generate fitness benefits but may also be associated with costs that trade-off with capacity for flexibility. Here, we review the literature on avian metabolic and muscle plasticity in response to season, temperature, migration and experimental manipulation of flight costs, and employ an integrative approach to explore the phenotypic flexibility of metabolic rates and skeletal muscle in wild birds. Basal (minimum maintenance metabolic rate) and summit (maximum cold-induced metabolic rate) metabolic rates are flexible traits in birds, typically increasing with increasing energy demands. Because skeletal muscles are important for energy use at the organismal level, especially to maximum rates of energy use during exercise or shivering thermogenesis, we consider flexibility of skeletal muscle at the tissue and ultrastructural levels in response to variations in the thermal environment and in workloads due to flight exercise. We also examine two major muscle remodeling regulatory pathways: myostatin and insulin-like growth factor -1 (IGF-1). Changes in myostatin and IGF-1 pathways are sometimes, but not always, regulated in a manner consistent with metabolic rate and muscle mass flexibility in response to changing energy demands in wild birds, but few studies have examined such variation so additional study is needed to fully understand roles for these pathways in regulating metabolic flexibility in birds. Muscle ultrastrutural variation in terms of muscle fiber diameter and associated myonuclear domain (MND) in birds is plastic and highly responsive to thermal variation and increases in workload, however, only a few studies have examined ultrastructural flexibility in avian muscle. Additionally, the relationship between myostatin, IGF-1, and satellite cell (SC) proliferation as it relates to avian muscle flexibility has not been addressed in birds and represents a promising avenue for future study.

Resting Rates of Blood Flow and Glucose Use per Neuron Are Proportional to Number of Endothelial Cells Available per Neuron Across Sites in the Rat Brain.

We report in a companion paper that in the mouse brain, in contrast to the 1,000-fold variation in local neuronal densities across sites, capillary density (measured both as capillary volume fraction and as density of endothelial cells) show very little variation, of the order of only fourfold. Here we confirm that finding in the rat brain and, using published rates of local blood flow and glucose use at rest, proceed to show that what small variation exists in capillary density across sites in the rat brain is strongly and linearly correlated to variations in local rates of brain metabolism at rest. Crucially, we show that such variations in local capillary density and brain metabolism are not correlated with local variations in neuronal density, which contradicts expectations that use-dependent self-organization would cause brain sites with more neurons to have higher capillary densities due to higher energetic demands. In fact, we show that the ratio of endothelial cells per neuron serves as a linear indicator of average blood flow and glucose use per neuron at rest, and both increase as neuronal density decreases across sites. In other words, because of the relatively tiny variation in capillary densities compared to the large variation in neuronal densities, the anatomical infrastructure of the brain is such that those sites with fewer neurons have more energy supplied per neuron, which matches a higher average rate of energy use per neuron, compared to sites with more neurons. Taken together, our data support the interpretation that resting brain metabolism is not demand-based, but rather limited by its capillary supply, and raise multiple implications for the differential vulnerability of diverse brain areas to disease and aging.

From a Demand-Based to a Supply-Limited Framework of Brain Metabolism.

What defines the rate of energy use by the brain, as well as per neurons of different sizes in different structures and animals, is one fundamental aspect of neuroscience for which much has been theorized, but very little data are available. The prevalent theories and models consider that energy supply from the vascular system to different brain regions is adjusted both dynamically and in the course of development and evolution to meet the demands of neuronal activity. In this perspective, we offer an alternative view: that regional rates of energy use might be mostly constrained by supply, given the properties of the brain capillary network, the highly stable rate of oxygen delivery to the whole brain under physiological conditions, and homeostatic constraints. We present evidence that these constraints, based on capillary density and tissue oxygen homeostasis, are similar between brain regions and mammalian species, suggesting they derive from fundamental biophysical limitations. The same constraints also determine the relationship between regional rates of brain oxygen supply and usage over the full physiological range of brain activity, from deep sleep to intense sensory stimulation, during which the apparent uncoupling of blood flow and oxygen use is still a predicted consequence of supply limitation. By carefully separating “energy cost” into energy supply and energy use, and doing away with the problematic concept of energetic “demands,” our new framework should help shine a new light on the neurovascular bases of metabolic support of brain function and brain functional imaging. We speculate that the trade-offs between functional systems and even the limitation to a single attentional spot at a time might be consequences of a strongly supply-limited brain economy. We propose that a deeper understanding of brain energy supply constraints will provide a new evolutionary understanding of constraints on brain function due to energetics; offer new diagnostic insight to disturbances of brain metabolism; lead to clear, testable predictions on the scaling of brain metabolic cost and the evolution of brains of different sizes; and open new lines of investigation into the microvascular bases of progressive cognitive loss in normal aging as well as metabolic diseases.

Host Energetics Explain Variation in Parasite Productivity across Hosts and Ecosystems.

AbstractParasites are thought to play a role in ecosystem energetics, in part because some ecosystems harbor a substantial amount of parasite biomass. Nevertheless, the extent to which parasite biomass accurately reflects the flow of energy from hosts to parasites-and the linkages between their energetics-remains unclear. Here, we estimate parasite community energetics at the host and ecosystem level and test predictions for parasite energetics using the metabolic theory of ecology. Across 27 host species, parasite community abundance declines with average individual parasite energy use Rp as and increases with host metabolic rate Rh as , which is inconsistent with metabolic theory. We next test whether the fraction of host energy that is allocated to parasitism is invariant across hosts. Our empirical analysis demonstrates that 85% of the variation in parasite community energy use can be explained by differences in host metabolic rate. However, parasite community energy use increases allometrically with host metabolic rate Rh as , suggesting that the fraction of host energy used by parasites declines with host metabolic rate. At the ecosystem level, we show that the energy flowing through parasite communities scales allometrically with the total rate of energy use by their fish hosts across three ecosystems. Importantly, directly examining energy flux revealed variation in parasite energy use among ecosystems that was not apparent when examining differences in biomass. Taken together, these results establish strong empirical links between host and parasite energetics, but our findings often did not align with predictions based on metabolic theory.

City-scale energetics: window on adaptive thermal insulation in North American cities

Previous research demonstrated that cities are similar to individual mammals in their relationship between the rate of energy use for heating and outdoor air temperature (Ta). At Tas requiring heating of indoor living spaces, the energy-Ta plot of a city contains information on city-wide thermal insulation (I), making it possible to quantify city-wide I by use of the city as the unit of measure. We develop methods for extracting this insulation information, deriving the methods from prior research on mammals. Using these methods, we address the question: in North America, are cities built in particularly cold locations constructed in ways that provide greater thermal insulation than ones built in thermally more moderate locations? Using data for 42 small and medium-size cities and two information-extraction methods, we find that there is a statistically significant inverse relationship between city-wide I and T10-year, the average city Ta over a recent 10-year period (range of T10-year: − 11 to 26 °C). This relationship represents an energy-conserving trend, indicating that cities in cold climates have greater built-in thermal insulation than cities in warm climates. However, the augmentation of insulation in cold climates is only about half as great as would be required to offset fully the increased energy cost of low Tas in a cold climate, and T10-year explains just 5–11% of the variance in measured insulation, suggesting that cities in North America vary greatly in the extent to which thermal insulation has been a priority in city development.

Has COVID-19 lockdown impacted on aged care energy use and demand?

In late March to April 2020 residential aged care facilities (RAC) in Australia were under COVID-19 lockdown. This paper explores whether the resultant restrictions on entry and exit and elimination of site group activities within RACs impacted on the total electricity use, peak demand and electrical load profiles.Six RACs in four different climate zones are analysed, comparing historical electricity load and demand profiles with the lockdown period. The facilities in warm regions showed largest reductions in energy use and peak demands. There was a peak demand timing shift in temperate regions and hot regions’ changes were negligible for energy use or peak demands.This study revealed the limitations of using aggregate data as the key performance indicator (KPI) – energy use per bed. Also, KPIs in relation to cooling degree days (or total cooling and heating degree days) have been examined and are not recommended for temperate regions or temperate seasons. The potential CO2 emission reduction from onsite renewable generation is quantified.Further research is to investigate energy use changes at circuit levels under lockdowns, and develop more nuanced KPIs that include the rate of energy use and the timing of that use.

Evidence for locally adaptive metabolic rates among ant populations along an elevational gradient.

As global temperatures rise, the mechanistic links between temperature, physiology and behaviour will increasingly define predictions of ecological change. However, for many taxa, we currently lack consensus about how thermal performance traits vary within and across populations, and whether and how locally adaptive trait plasticity can buffer warming effects. The metabolic cold adaptation hypothesis posits that cold environments (e.g. high elevations and latitudes) select for high metabolic rates (MR), even after controlling for body size differences, and that this enables high activity levels when an organism is near its cold lower thermal limits. Steep MR reaction norms are further predicted at cold temperatures to enable rapid behavioural activation with rising temperatures needed to exploit brief thermal windows suitable for performing eco-evolutionary tasks. We tested these predictions by performing common garden experiments comparing thermal reaction norms of MR (from 15 to 32°C) and behaviour (from 10 to 40°C) across populations of the ant Aphaenogaster iberica sampled from a 2km elevation gradient in the Sierra Nevada Mountains of southern Spain. As predicted, high-elevation ants had higher MR and steeper MR-temperature reaction norms. However, higher rates of energy use did not yield the predicted benefits of steeper activity-level reaction norms. The evidence for locally adaptive metabolic physiology only became apparent at intermediate temperatures, highlighting the importance of testing thermal performance hypotheses across thermal gradients, rather than focusing only on performance at thermal limits (i.e. critical thermal values). The partial support for the metabolic cold adaptation hypothesis highlights that while organisms likely show a wealth of unexplored metabolic temperature plasticity, the physiological mechanisms and eco-evolutionary trade-offs underlying such local adaptation remain obscure.

Fuzzy rule selection using artificial bee colony optimisation algorithm

Wireless sensor network (WSN) brings an innovative model with embedded system with restrictions of computing ability, intercommunication, storage capacity, and energy resource which is applied for a high range of applications in the situations when constructing the network based on conventional infrastructure is not feasible. Clustering with WSN is a successful technique to reduce the rate of energy use of sensor node. The fuzzy logic calculates the cluster head (CH) selection probability depending on the node's earlier communication history to choose the CH. The set of rules applied to the fuzzified input is the fuzzy rule base. The output of the inference engine is changed to crisp output by defuzzification. Artificial bee colony (ABC) is an optimisation protocol owes its inspiration to the exploration behaviour of honey bees. It is a comparatively innovative optimisation algorithm which has proven to be on par with classical bio-inspired protocols. This work on ABC optimisation algorithm is suggested for selecting fuzzy rules. Rule selection methods combine different rules from fuzzy rule set to decrease the rules while maintaining the performance of the system. The rules that decrease the performance of the system are removed, to get a fuzzy rule set with improved performance.

Author Correction: Quantification of energy and carbon costs for mining cryptocurrencies

In the version of this Analysis originally published, in the paragraph that starts “On the basis of our 2017 estimates…” the word ‘trillion’ was mistakenly used three times in relation to rates of energy use; it should have read ‘billion’. This has now been corrected.

Running Mechanics and Metabolic Responses With Water Bottles and Bottle Belt Holders.

To determine whether differential kinematics, kinetics, rates of energy use, and cardiopulmonary responses occur during running with water bottles and bottle belt holders compared with running only. Trained runners (N = 42; age 27.2 [6.4]y) ran on an instrumented treadmill for 4 conditions in a randomized order: control run (CON), handheld full water bottle (FULL; 16.9 fluid oz; 454g), handheld half-full water bottle (HALF; 8.4 fluid oz; 227g), and waist-worn bottle belt holder (BELT; hydration belt; 676g). Gas exchange was measured using a portable gas analyzer. Kinetic and kinematic responses were determined by standard 3-dimensional videographic techniques. Interactions of limb side (right and left) by study condition (CON, FULL, HALF, and BELT) were tested for rates of oxygen use and energy expenditure and kinematic and kinetic parameters. No significant limb-side × condition interactions existed for rates of oxygen use or energy expenditure. A significant interaction occurred with sagittal elbow flexion (P < .001). Transverse pelvic-rotation excursions differed on average 3.8° across conditions. The minimum sagittal hip-flexion moment was higher in the right leg in the HALF and BELT conditions compared with CON (P < .001). Carrying water by hand or on the waist does not significantly change the kinematics of running motion, rates of oxygen use and energy expenditure, or cardiopulmonary measures over short durations. Runners likely make adjustments to joint moments and powers that preserve balance and protect the lower-extremity joints while maintaining rates of oxygen use and energy expenditure.

On the Design of Dual Energy Harvesting Communication Links With Retransmission

In this paper, we consider retransmission-based point-to-point dual energy harvesting (EH) links, where both the transmitter and receiver are EH nodes (EHNs). The transmitter needs to periodically send a packet to the receiver and the packet is dropped if it is not delivered within a given number of slots. The goal is to find a retransmission index-based power management policy (RIP), which minimizes the packet drop probability (PDP). To this end, first, we establish the near-optimality of policies that operate in the energy unconstrained regime (EUR) , i.e., the regime where the average rate of energy use at each EHN is less than the average harvesting rate. Specifically, we analytically show that for such policies, the gap between the PDP of the dual EH systems with finite and infinite capacity batteries decreases exponentially with the size of the battery at the transmitter and receiver. Next, we show that, in the EUR, the non-convex problem of designing optimal RIPs can be reformulated as a geometric program , which leads to a provably convergent and computationally efficient solution. We design the RIPs for both slow and fast fading channels, and with two different retransmission protocols, namely, the automatic repeat request (ARQ) and hybrid ARQ with chase combining. Numerical results obtained through Monte Carlo simulations show that the proposed RIPs outperform the state-of-the-art policies.

Winter warming effects on overwinter survival, energy use, and spring emergence ofCerotoma trifurcata(Coleoptera: Chrysomelidae)

Bean leaf beetle Cerotoma trifurcata (Forster) (Coleoptera: Chrysomelidae) is a pest of soybean in the U.S.A. and is becoming a concern in Canada. The projected increase in winter temperatures under climate change could affect overwinter survival, timing of spring emergence and, ultimately, the severity of this pest. We assessed the potential effects of warmer winters in field experiments performed in three consecutive years. Three warming levels were applied: (i) heated approximately 4 °C above ambient; (ii) unheated with snow cover left intact; and (iii) unheated with snow cover removed. Survival and date of emergence were assessed in all years, and beetle lipid content was analyzed in 1 year to determine rates of energy use. Overwinter survival was 6.5–14.5% among years. Winter warming inconsistently affected overwinter survival: increasing survival in one winter, decreasing survival in the warmest winter and having no effect in one winter. Beetles that received supplemental winter warming emerged approximately 2 weeks earlier in spring, and lipid content did not differ among treatment groups. Earlier spring emergence may allow for the production of an additional generation per year of C. trifurcata under future climate change. However, further experiments are required to establish the relationship between overwinter survival and subsequent beetle population growth to determine potential pest status and best management practices under future climate conditions.

A cross‐seasonal perspective on local adaptation: metabolic plasticity mediates responses to winter in a thermal‐generalist moth

SummaryThe physiological and ecological impact of the thermal environment across life stages can result in trade‐offs that determine fitness and population dynamics. Understanding mechanisms and consequences of local adaptation for any organism that overwinters requires taking a cross‐seasonal perspective.We used a trait‐based approach to distinguish variation among ecotypes in ecological and physiological responses to overwintering conditions. We used fall webworms (Hyphantria cunea;Lepidoptera:Arctiidae) fromOttawa,Ontario andColumbusOhio, representing the centre and periphery of the native range.We hypothesized that populations would be locally adapted to their overwintering environments, with fitness maximized under natal overwintering conditions. We predicted that this local adaptation would result from modulation of rates of energy use, growth and development.Each ecotype had higher overwinter survival in their natal compared with non‐natal winter environment, and this was associated with larger pupal mass, size and carbohydrate reserves at the end of winter. This suggests that the ecotypes are locally adapted to winter conditions. Larger adults laid more eggs, but there was no effect of ecotype or environment on fecundity.Pupae overwintering at warm, energetically demanding, southern temperatures suppressed metabolic rates in autumn, and developed more quickly in the spring, compensating for energetic demands of warmer winters. Northern ecotypes had lower thermal sensitivity of metabolism, leading to higher metabolic rates at cool temperatures that correlated with faster post‐winter development.Local adaptation to winter conditions suggests performance of peripheral populations may not be enhanced by warming winters. Decoupling of winter and growing season temperatures may negatively impact ectotherms.

Life in the Lizard Slow Lane: Gila Monsters Have Low Rates of Energy Use and Water Flux

Field metabolic rates (FMR) and water influx rates (WIR) were measured in Gila Monsters (Heloderma suspectum) in the Mojave Desert of southern Nevada. Gila Monsters had rates of energy use that were less than half of those expected for lizards of their size, including species that live in arid habitats. Free-living Gila Monsters also had comparatively low water flux rates. The annual energy requirements of adult Gila Monsters averaged approximately 3,766 kJ, with two-thirds of the total (2,533 kJ) allocated to activity while above ground, and one-third to resting metabolism (1,233 kJ; mostly while below ground). Unusually low rates of resting metabolism caused relative costs of activity to be high: compared to other lizards, Gila Monsters have among the highest proportional use of energy for activity, relative to total energy use. The average annual water expenditure of adults was approximately 775 mL, and lizards achieved positive mass balance by drinking rain water during the late summer monsoon season....