Reduction In Available Energy Research Articles

Olduvai domain expression downregulates mitochondrial pathways: implications for human brain evolution and neoteny.

Encoded by the NBPF gene family, Olduvai (formerly DUF1220) protein domains have undergone the largest human lineage-specific copy number expansion of any coding region in the genome. Olduvai copy number shows a linear relationship with several brain size-related measures and cortical neuron number among primates and with normal and disease-associated (micro- and macrocephaly) variation in brain size in human populations. While Olduvai domains have been shown to promote proliferation of neural stem cells, the mechanism underlying such effects has remained unclear. Here, we investigate the function of Olduvai by transcriptome and proteome analyses of cells overexpressing NBPF1, a gene encoding 7 Olduvai domains. Our results from both RNAseq and mass spectrometry approaches suggest a potential downregulation of mitochondria. In our proteomics study, a Gene Ontology (GO) enrichment analysis for the downregulated proteins revealed a striking overrepresentation of the biological process related to the mitochondrial electron transport chain (p value: 1.81e-11) and identified deregulation of the NADH dehydrogenase activity (p value: 2.43e-11) as the primary molecular function. We verify the reduction of apparent mitochondria via live-cell imaging experiments. Given these and previous Olduvai findings, we suggest that the Olduvai-mediated, dosage-dependent reduction in available energy via mitochondrial downregulation may have resulted in a developmental slowdown such that the neurogenic window among primates, and most extremely in humans, was expanded over a greater time interval, allowing for production of greater numbers of neurons and a larger brain. We further suggest that such a slowdown may extend to other developmental processes that also exhibit neotenic features.

PSXV-16 Association of Experience and pre-Race Behavior in Performance Among Racing Quarter Horses

Abstract The annual average cost of maintaining a racehorse will typically outweigh its earning, making it important that the horse performs above average. The goal of this study was to investigate if the age or experience level of a racehorse could be associated with performance. This study observed pre-racing Quarter Horses (n = 1,033) behavior during one racing season at Delta Downs racetrack (Vinton, LA). The horses were placed into groups based on race experience (0-2, 3-10, and 11+ total races). Horse pre-race before saddling (BSAD), saddling (SAD), after saddling (ASAD) and post-parade (POST) behaviors (calm, ready or nervous) were observed to identify if the horse was calm, ready, or nervous. The behavior types were recorded as categorical variables in this study and were analyzed using proc FREQ, and the finish was recorded as a quantitative variable and were analyzed using proc GLM with (P < 0.05) being statistically different. Horses with 11+ races had a mean±SE finish (4.9±0.1), better (P< 0.05), than horses with 3 to 10 races (4.8±0.2) and both were better (P< 0.05) than horses with 0 to 2 races experience (5.5±0.2). Race experience was also associated with pre-race behaviors. There were more (P< 0.05) horses with 0 to 2 races experience that were classified as nervous during the BSAD (39/326, 11.9%), SAD (29/326, 8.9%), ASAD (13/325, 4.0%) and POST (17/320, 5.3%) compared with horses with 11 plus races experience; BSAD (5/343, 1.5%), SAD (16/343, 4.7%), ASAD (4/343, 1.2%) and POST (1/341, 0.3%). The improvement in race finish among horses with more experience could be that they have been placed in more suitable levels of racing competition compared with unexperienced horses. However, the additional racing experience was associated with less stress or fear-full behaviors pre-race that can result in a reduction of available energy to possibly prolonged elevated cortisol concentrations.

Characterizing the stress response in juvenile Delta smelt exposed to multiple stressors

The Delta Smelt (Hypomesus transpacificus), once an abundant fish endemic to the Sacramento-San Joaquin Estuary, is now on the brink of extinction. Due to the high sensitivity of this species, knowledge of their stress response will be vital to their future survival and sustainability. Understanding the magnitude and kinetics of cortisol induction in Delta Smelt will provide valuable information when interpreting the degree of environmentally relevant stressors, such as warming and predator exposure. As little is known about the primary stress response and cortisol dynamics in Delta Smelt, the first aim of this study was to measure basal and maximal whole-body cortisol prior to and following exposure to a sublethal and significant netting stress at 17 and 21 °C. Our findings reveal that juvenile Delta Smelt held at 21 °C display an exacerbated stress response and a reduction in available energy compared to fish held at 17 °C. There was no evidence of the secondary stress response to the netting stress as whole-body glucose and lactate levels in treatment groups remained similar to basal values. The second aim of this study was to investigate the effect of a largemouth bass (Micropterus salmoides) predator cue, which was found to induce a significant increase in cortisol relative to control levels in juvenile Delta Smelt. Indices such as cortisol can be used as bioindicators of stress in the field and results from this study suggest that moderate temperatures and reduced predation are optimal release conditions during hatchery-based supplementation to minimize stress to this highly sensitive species.

The Local Biophysical Response to Land-Use Change in HadGEM2-ES

AbstractThe biophysical response to a local change in land use is calculated using the HadGEM2-ES Earth system model. The biophysical temperature response is found to be a small residual of three large opposing flux responses: available energy, sensible heat, and latent heat. Deforestation reduces available energy, which is balanced by a reduction in heat lost via turbulent fluxes. However, the changes in turbulent heat fluxes are not simply a response to the reduction in available energy; rather, they are a direct response to land-use change, caused by reduced roughness length and, in the tropics, an increase in the Bowen ratio. Evaluation against satellite-derived observational datasets shows that in response to deforestation, the model has too much albedo-driven cooling and too little latent-heat-driven warming, leading to a large cooling bias.

The histone methyltransferase G9a regulates tolerance to oxidative stress-induced energy consumption.

Stress responses are crucial processes that require activation of genetic programs that protect from the stressor. Stress responses are also energy consuming and can thus be deleterious to the organism. The mechanisms coordinating energy consumption during stress response in multicellular organisms are not well understood. Here, we show that loss of the epigenetic regulator G9a in Drosophila causes a shift in the transcriptional and metabolic responses to oxidative stress (OS) that leads to decreased survival time upon feeding the xenobiotic paraquat. During OS exposure, G9a mutants show overactivation of stress response genes, rapid depletion of glycogen, and inability to access lipid energy stores. The OS survival deficiency of G9a mutants can be rescued by a high-sugar diet. Control flies also show improved OS survival when fed a high-sugar diet, suggesting that energy availability is generally a limiting factor for OS tolerance. Directly limiting access to glycogen stores by knocking down glycogen phosphorylase recapitulates the OS-induced survival defects of G9a mutants. We propose that G9a mutants are sensitive to stress because they experience a net reduction in available energy due to (1) rapid glycogen use, (2) an inability to access lipid energy stores, and (3) an overinduced transcriptional response to stress that further exacerbates energy demands. This suggests that G9a acts as a critical regulatory hub between the transcriptional and metabolic responses to OS. Our findings, together with recent studies that established a role for G9a in hypoxia resistance in cancer cell lines, suggest that G9a is of wide importance in controlling the cellular and organismal response to multiple types of stress.

The hypoxic transcription factor KlMga2 mediates the response to oxidative stress and influences longevity in the yeast Kluyveromyces lactis.

Hypoxia is defined as the decline of oxygen availability, depending on environmental supply and cellular consumption rate. The decrease in O2 results in reduction of available energy in facultative aerobes. The response and/or adaptation to hypoxia and other changing environmental conditions can influence the properties and functions of membranes by modifying lipid composition. In the yeast Kluyveromyces lactis, the KlMga2 gene is a hypoxic regulatory factor for lipid biosynthesis-fatty acids and sterols-and is also involved in glucose signaling, glucose catabolism and is generally important for cellular fitness. In this work we show that, in addition to the above defects, the absence of the KlMGA2 gene caused increased resistance to oxidative stress and extended lifespan of the yeast, associated with increased expression levels of catalase and SOD genes. We propose that KlMga2 might also act as a mediator of the oxidative stress response/adaptation, thus revealing connections among hypoxia, glucose signaling, fatty acid biosynthesis and ROS metabolism in K. lactis.

Silicon Photoelectrode Thermodynamics and Hydrogen Evolution Kinetics Measured by Intensity-Modulated High-Frequency Resistivity Impedance Spectroscopy.

We present an impedance technique based on light intensity-modulated high-frequency resistivity (IMHFR) that provides a new way to elucidate both the thermodynamics and kinetics in complex semiconductor photoelectrodes. We apply IMHFR to probe electrode interfacial energetics on oxide-modified semiconductor surfaces frequently used to improve the stability and efficiency of photoelectrochemical water splitting systems. Combined with current density-voltage measurements, the technique quantifies the overpotential for proton reduction relative to its thermodynamic potential in Si photocathodes coated with three oxides (SiOx, TiO2, and Al2O3) and a Pt catalyst. In pH 7 electrolyte, the flatband potentials of TiO2- and Al2O3-coated Si electrodes are negative relative to samples with native SiOx, indicating that SiOx is a better protective layer against oxidative electrochemical corrosion than ALD-deposited crystalline TiO2 or Al2O3. Adding a Pt catalyst to SiOx/Si minimizes proton reduction overpotential losses but at the expense of a reduction in available energy characterized by a more negative flatband potential relative to catalyst-free SiOx/Si.

Wind speed characteristics and implications for wind power generation: Cape regions, South Africa


 
 
 Spatio-temporal dynamics of near-surface wind speeds were examined across the Northern, Western and Eastern Cape regions of South Africa. The regions assessed were geographically subdivided into three zones: coastal, coastal hinterland and inland. Wind speed data (10 m) were evaluated at monthly, seasonal, annual and zonal resolutions, with the aim to establish wind speed attributes and trends. Data from 19 weather stations with high-resolution wind records between 1995 and 2014 were evaluated. The majority of stations (79%) recorded a decrease in mean annual wind speed over the study period. The mean rate of decrease across all stations over the 20-year period equates to -1.25%, quantifying to an annual decrease of -0.002 m/s/year (-0.06% pa). The largest seasonal decline of -0.006 m/s/year (-0.15% pa) was recorded in summer. Statistically significant declines in mean annual wind speed are somewhat more pronounced for the coastal zone (-0.003 m/s/year, -0.08% pa) than over interior regions (-0.002 m/s/year, -0.06% pa) for the study period. The largest decrease (-0.08% pa) was recorded for the coastal zone, followed by the inland zone (-0.06% pa), equating to an annual reduction in available energy of 0.18% pa and 0.09% pa, respectively. When considering all stations over the study period, the mean inter-annual variability is 3.11%. Despite such decreases in wind speed, the variance identified in this study would not have posed any risk to power generation from wind across the assessed stations, based on the period 1995 to 2014.
 
 
 
 
 Significance: 
 
 
 
 Mean recorded wind speed decreases have been marginal under recent (last 20 years) climatic conditions and change, thus adding confidence to the justification by the South African government to procure additional wind-generated electricity capacity.
 Wind speed trends and variance measured over the research period (1995–2014) for the Cape stations in this study, would not have posed any risk to power generation from wind.
 Only four stations (28.6%) recorded statistically significant trends at the 0.05% level; of these 75% were decreasing trends.
 Coastal zones recorded a statistically larger decrease in mean wind speed compared to inland regions.
 When considering all stations over the period 1995–2014, the mean inter-annual variability is 3.11%.
 
 
 

G-Functions for multiple interacting pile heat exchangers

Pile heat exchangers – where heat transfer pipes are cast into the building piled foundations – offer an opportunity to use ground energy systems without the additional construction costs related to the provision of special purpose heat exchangers. However, analysis methods for pile heat exchangers are still under development. In particular there is an absence of available methods and guidance for the amount of thermal interaction that may occur between adjacent pile heat exchangers and the corresponding reduction in available energy that this will cause. This is of particular importance as the locations of foundation piles are controlled by the structural demands of the building and cannot be optimised with respect to the thermal analysis. This paper presents a method for deriving G-functions for use with multiple pile heat exchangers. Example functions illustrate the primary importance of pile spacing in controlling available energy, followed by the number of piles within any given arrangement. Significantly it was found that the internal thermal behaviour of a pile is not influenced appreciably by adjacent piles.

Atmospheric and soil moisture controls on evapotranspiration from above and within a Western Boreal Plain aspen forest

The Western Boreal Plain of North Central Alberta comprises a mosaic of wetlands and aspen (Populus tremuloides) dominated uplands where precipitation (P) is normally exceeded by evapotranspiration (ET). As such these systems are highly susceptible to the climatic variability that may upset the balance between P and ET. Above canopy evapotranspiration (ETC) and understory evapotranspiration (ETB) were examined using the eddy covariance technique situated at 25.5 m (7.5 m above tree crown) and 4.0 m above the ground surface, respectively. During the peak period of the growing seasons (green periods), ETC averaged 3.08 mm d−1 and 3.45 mm d−1 in 2005 and 2006, respectively, while ETB averaged 1.56 mm d−1 and 1.95 mm d−1. Early in the growing season, ETB was equal to or greater than ETC once understory development had occurred. However, upon tree crown growth, ETB was lessened due to a reduction in available energy. ETB ranged from 42 to 56% of ETC over the remainder of the snow-free seasons. Vapour pressure deficit (VPD) and soil moisture (θ) displayed strong controls on both ETC and ETB. ETC responded to precipitation events as the developed tree crown intercepted and held available water which contributed to peak ETC following precipitation events >10 mm. While both ETC and ETB were shown to respond to VPD, soil moisture in the rooting zone is shown to be the strongest control regardless of atmospheric demand. Further, soil moisture and tension data suggest that rooting zone soil moisture is controlled by the redistribution of soil water by the aspen root system. Copyright © 2013 John Wiley & Sons, Ltd.

The Corrosion Effects on the Structural Integrity of Reinforcing Steel

An experimental study conducted on 12 mm diameter, artificially corroded BSt500s steel rebars, showed that the mass loss, the fatigue limit, and the life expectancy were reduced according to the level of corrosion. Rebar corrosion has a great impact on the mass loss, mechanical properties, low cycle fatigue (LCF) and there is strong indication that embrittlement takes place. The extended salt-spray exposure enhanced the damage and promoted extended creation of pits and perforations suggesting progressive embrittlement and reduction of the available energy, justified by the SEM micrograph results. The low cycle strain-controlled fatigue testing under ±1, ±2.5, and ±4% constant amplitude strain indicated that the corroded steel bars exhibit gradual reduction in available energy, number of cycles to failure, and load bearing ability. For the ±1% strain level the fatigue limit was reduced considerably as the level of corrosion increased due to mass loss and reduction of the exterior martensitic layer. In addition, a drastic drop in the energy density of the specimens was observed with creation of stress concentration points. At ±2.5% and ±4% strain levels, the fatigue limit was reduced dramatically mainly due to accumulated damage from plastic deformation and minimally due to corrosion. Anti-seismic design that ignores the influence of corrosion and cumulative damage due to plastic deformation, and the mechanical behavior of reinforcing steel during severe ground motion, could lead to unpredictable performance.

Corrosion of reinforcing steel and low cycle fatigue behaviour

AbstractChloride induced corrosion of reinforcing steel can be highly detrimental and of great influence on the low cycle fatigue (LCF) characteristics. An experimental study conducted on BSt500s reinforcing steel, showed that the LCF and life expectancy were reduced considerably according to the level of corrosion. Low cycle strain controlled fatigue testing under ± 1 and ± 2.5% constant amplitude strain indicated that the corroded steel bars exhibit gradual reduction in available energy, number of cycles to failure and the load bearing ability. Formation of irregularities such as pits, notches and cavities occurred on the corroded steel surface and stress concentration points were developed which are highly localized at imperfections and especially at the rib bases. The experimental investigation of the corroded specimens subjected to LCF showed that the life expectancy, the remaining energy density and the strength properties were reduced considerably as a result of these irregularities combined with the mass loss and reduction of the exterior hard layer of martensite. Structural design capable of resisting seismic activity that does not account for the reduction of the load bearing ability and life expectancy as well as the cumulative plastic deformation of the steel reinforcement due to corrosion and loading history that a structure will be subjected in harsh climatic environments and ground oscillating motion could lead to serious and unpredictable performance.

Mechanical Properties of Reinforcing Steel and Fatigue Behavior in Corrosive Environment

Corrosion of reinforcing steel has a great impact on the mass reduction and high- and low-cycle fatigue. An experimental study showed that the mass loss, the fatigue limit and the life expectancy were reduced by approximately 1.50-3.00%, 20-40%, and 55-75%, respectively, according to the level of corrosion. Low-cycle strain controlled fatigue testing under ±1% and ±2.5% constant amplitude strain, indicated that the corroded steel bars exhibit gradual reduction in available energy, number of cycles to failure and the load-bearing ability. Formation of pits and notches took place on the corroded steel surface and stress concentration points were developed which are highly localized at imperfections and especially at the rib bases. The fatigue limit was reduced considerably since the existence of ribs and the formation of pits and notches combined with the mass loss led to reduction of the exterior hard layer of martensite and drastic drop in the energy density of the corroded specimens. Antiseismic design that does not take into account the maximum and cumulative plastic deformation demands and the strain history that a structure will suffer under severe ground motion could lead to unpredictable performance.

Influences of food quality and quantity on the male reproductive organs of a seasonally breeding rodent, the pouched mouse(Saccostomus campestris), from a seasonal but unpredictable environment

Reproduction in the pouched mouse (Saccostomus campestris) is inhibited in winter in the field and this seasonality is not controlled by photoperiod alone. The present study examines the hypothesis that reproduction in the pouched mouse is opportunistic (sensu Bronson 1989) and that the winter inhibition of reproduction is controlled by a reduction in either food quantity or quality. Food restriction (70 % of normal daily food intake) for six weeks, under short day conditions, was associated with a significant decrease in body fat index and mass of the accessory glands, testes and epididymides, while a high-fibre diet resulted in a significant reduction in fat index and masses of both the accessory glands and epididymides. A low-fibre/low-protein diet had no significant effect on either fat index or masses of the reproductive organs. Although the three experimental diets resulted in assimilation of significantly less energy than the controls, they did not inhibit spermatogenesis. We conclude that reproduction in the pouched mouse in the Eastern Cape Province is probably opportunistic and that the winter inhibition of reproduction may be controlled by a reduction in available energy which results from a combination of the lower ambient temperatures of winter and reduced food quantity and/or quality.

Determination of an ageing factor for lead/acid batteries. 1. Kinetic aspects

The capacity of lead/acid batteries decreases with the number of cycles. This process is known as ageing. The reduction of capacity affects not only the operation time but also the performance of the accumulator and of the system attached to the battery. One of the main procedures affected by the battery ageing is the determination of the state-of-charge. In this paper, a parameter called ‘ageing factor’, f a , which represents the reduction of the available energy in lead/acid batteries, is introduced. A method to calculate this factory and its incidence on battery performance has also been developed. The method is intended to predict ‘ageing’ effects on lead/acid batteries as a non-destructive method, as well as on-line battery operation. The method is based on the effective reduction in electrolyte specific gravity in a fully charged lead/acid battery computed from the change of the slope of the electrolyte density during charge with the number of cycles, and the subsequent reduction in discharge time. A correlation process between the reduction of the energy delivered by the electrochemical cell, the reduction of the discharge time, and the apparent change of the slope of electrolyte density has been developed, resulting in an analytical expression that may be used to compute the effective reduction in available energy in lead/acid batteries. The results of the experiments have proven the merit of the proposed system: the predicted values are in good agreement with experimental data, the associated error in the a estimation being lower than 9%, a result which has been considered acceptable to validate the proposed method.

Estimation of transpiration by single trees: comparison of a ventilated chamber, leaf energy budgets and a combination equation

Ventilated chambers have been used to measure transpiration rates of various Eucalyptus species. However the microclimate within a chamber differs from natural conditions, leading to possible bias in the measurements. The validity of transpiration rates measured by ventilated chambers was assessed using two techniques which could be applied both with and without the chamber in place. The Penman-Monteith equation, applied to single leaves, provided one set of transpiration estimates for both chamber positions. A second set was obtained using a leaf energy budget method which utilized paired leaves, one of which was prevented from transpiring, while the other behaved normally. Temperature differences between the two leaves and boundary layer conductances measured in situ were used to estimate transpiration rates for normal leaves through solution of leaf energy budget equations. Transpiration rates within the ventilated chamber were reduced by up to 30% around midday relative to undisturbed conditions, according to estimates using the Penman-Monteith equation. Enhanced transpiration during late afternoon was also predicted. Diminished transpiration rates within the ventilated chamber were caused by a marked reduction in available energy when the chamber walls were raised. Recommendations are presented for techniques to measure net radiation absorbed by leaves within a tree canopy. Leaf energy budget measurements on 9–12 paired leaves did not confirm predictions from the Penman-Monteith equation that transpiration rates within the ventilated chamber were lower than under natural conditions. Midday transpiration measurements from leaf energy budgets were ∼ 25% higher than Penman-Monteith predictions when the ventilated chamber was in position and ∼ 25% lower when it was down, thus suggesting little change in transpiration rates with chamber position. Small differences in transpiration rates between trees cannot readily be resolved by any of the estimation techniques used in this study because of inherent experimental uncertainties in each method.

The exudation of solutes during senescence of oat leaves

Exudation of cations and of amino acids from detached oat seedling leaves (Avena sativa L. cv. Victory) floated on water or solutions was measured under varied conditions. A small amount of exudation in the first 4 h, greater in the dark than in white light, is followed, one to 8 days later, by a relatively great increase which approximately accompanies senescence. This second increase is delayed by kinetin and is accelerated by abscisic acid or methyl jasmonate. both of which accelerate senescence. A nitrogen atmosphere (in darkness) causes immediate large exudation, mainly of potassium ions, and this is effectively delayed by light. There are two exceptions to the parallel between exudation and senescence; n‐pentanol, which strongly delays senescence in darkness, nevertheless increases exudation both of potassium and of amino acids, probably due to a direct effect on the plasmalemma. Cycloheximide, which also delays senescence, increases the exudation somewhat. Kinetin prevents or delays exudation under all conditions. Thus, the permeability of the plasmalemma increases greatly along with other criteria of senescence, but this change is probably not the principal cause of the senescence syndrome. Some of the effects are considered to result from reduction in available energy and others from a direct influence on plasmalemma permeability.

有効エネルギーによる履歴的表現に関する理論的吟味

An examination of hereditary expression is essential for the study of available energy. The law of reduction of available energy is adapted by the law of conservation of energy. Considering such progress, hereditary expression of available energy is the field which is the tardiest in research and unsolved yet. In this paper, considering a mathematical model of energy flow, a mechanism of available energy loss is analyzed on hierarchical structure. And hereditary expression of the system is made by available energy flow.