Increase In Environmental Temperature Research Articles

Plasticity cannot fully compensate evolutionary differences in heat tolerance across fish species.

Understanding how evolution and phenotypic plasticity contribute to variation in heat tolerance is crucial to predict responses to warming. Here we analyze 272 thermal death time curves of 53 fish species acclimated to different temperatures and quantify their relative contributions. Analyses show that evolution and plasticity account, respectively, for 80.5 % and 12.4 % of the variation in elevation across curves, whereas their slope remained invariant. Evolutionary and plastic adaptive responses differ in magnitude, with heat tolerance increasing 0.54 ºC between species and 0.32 ºC within species for every 1 ºC increase in environmental temperatures. After successfully predicting critical temperatures under ramping conditions to validate these estimates, we show that fish populations can only partly ameliorate the impact of warming waters via thermal acclimation and this deficit in plasticity could increase as the warming accelerates.

Role of Nannochloropsis Oculata supplement in improving performance, antioxidant status, blood metabolites, and egg quality of laying hens under hot environmental conditions

The increase in environmental temperature led to economic losses in the poultry industry, urging the use of feed supplements to mitigate the negative effects on chick's welfare and performance. Therefore, this study aimed to examine the effects of marine microalgae (Nannochloropsis Oculata, N. Oculata) additive on commercial Brown Lohmann laying hen's performance, blood metabolites, and antioxidant status under hot environmental conditions. One hundred and eighty birds (34 weeks old with an initial body weight of 1885 ± 23.5 g) were used till 47 weeks. The birds were divided into three equal groups (birds in each group were distributed into four equal replicates 15 hens/ replicate). The 1st group was the control (CON) and was fed the basal diet, while the 2nd (TR1) and 3rd (TR2) groups were fed the basal diet supplemented with 0.5 and 1.0% of N. Oculata, respectively. The results showed that total protein and globulin concentrations increased (P < 0.05) in treated groups compared with the control group, whereas, albumin concentration increased (P < 0.05) in TR2 compared to the control group. The concentration of ALT and AST decreased in hens fed N. Oculata. Supplementing with N. Oculata reduced serum cholesterol and creatinine concentrations, while glucose concentration increased (P < 0.05) in the treated groups compared to the control group. Serum calcium, total antioxidant capacity (TAC), Triiodothyronine (T3), and progesterone increased (P < 0.05) in hens fed N. Oculata. N. Oculata supplement improved production performance through a positive effect on egg number, egg weight, egg mass, feed conversion ratio, and mortality rate. In addition, the overall mean of shell thickness increased (P < 0.05) in hens fed N. Oculata. It can be concluded that the supplementation of 1.0% N. Oculata to the laying hens' diet enhanced productive performance, serum constituents, and antioxidant status under hot environmental conditions.

Molecular dynamics simulation of micro-explosion of water-in-heavy oil emulsion droplets

Evaporation and micro-explosion of water-in-oil emulsion droplets composed of water and polycyclic aromatic hydrocarbons (PAHs) were characterized by molecular dynamics simulation at 300–600 °C and 0.2–1.5 MPa. The driving force for micro-explosion of emulsion droplets comes from the difference between environment temperature and boiling point of water. Also, the evaporation potential of oil phase has a significant influence on the intensity of micro-explosion. An increase in water droplet diameter within a certain range, an increase in environment temperature and a decrease in environment pressure are beneficial to increasing the probability and intensity of micro-explosion. After an intense micro-explosion, the number of oil molecules in the resulting child clusters can be less than 20 % of the initial number of oil molecules in the emulsion droplets. The time required for complete evaporation of emulsion droplets depends on the evaporation of the largest child cluster produced by micro-explosion.

Research on the Impact and Parameters of Liquid-Cooling Garment on Thermal Comfort

Liquid-cooling garment (LCG) can alleviate heat stress and improve thermal comfort in high-temperature environments. This study conducted human experiments to assess the impact of the LCG on physiological parameters and subjective evaluations during heat stress. Then, a numerical parametric study was performed to examine the effect of environmental temperature, inlet temperature, and flow rate on LCG performance. The results demonstrate a significant inhibition of physiological parameter escalation compared to the absence of protective measures. Specifically, skin temperature exhibited a reduction ranging from 1.6% to 4.9%, whereas heart and core temperature rise rates experienced respective decreases of 27.5% and 24.2%. Additionally, there was a notable reduction of 20.76% in sweat production. Elevated skin temperature was associated with heightened thermal sensation and diminished thermal comfort. Moreover, applying the LCG resulted in a noteworthy decrease of 28.5% and 14% in the physiological and perceived stress indexes, respectively. Adjusting inlet temperature better reduces skin temperature than flow rate when environmental temperature and labor intensity increase. Lowering inlet water temperature improved LCG performance. An inlet temperature of 20 °C and a flow rate of 500 mL/min were optimal for moderate labor.

Optical Bistability of Graphene Incorporated into All-Superconducting Photonic Crystals

We investigated optical bistability and its temperature dependence in a composite system composed of an all-superconducting photonic crystal and graphene. The photonic crystal, constructed from two types of superconducting sheets, and which is temperature-sensitive and can greatly localize the electric field, alternately supports a defect mode in a cryogenic environment. Graphene is located at the strongest site in the electric field, so the third-order nonlinearity of graphene is enhanced tremendously, and, subsequently, low thresholds of optical bistability are achieved in the near-infrared region. The thresholds of optical bistability and the interval between the upper and lower thresholds decrease with the increase in environmental temperature, while the bistable thresholds increase with the addition of the incident wavelength. Furthermore, the critical threshold triggering optical bistability can be modulated by environment temperature and the periodic number of photonic crystals as well. The simulations may be found to be applicable for all temperature-sensitive optical switches or sensors in cryogenic environments.

Deciphering Structural Traits for Thermal and Kinetic Stability Across Protein Family Evolution through Ancestral Sequence Reconstruction.

Natural proteins are frequently marginally stable, and an increase in environmental temperature can easily lead to unfolding. As a result, protein engineering to improve protein stability is an area of intensive research. Nonetheless, since there is usually a high degree of structural homology between proteins from thermophilic organisms and their mesophilic counterparts, the identification of structural determinants for thermo-adaptation is challenging. Moreover, in many cases, it has become clear that the success of stabilization strategies is often dependent on the evolutionary history of a protein family. In the last few years, the use of ancestral sequence reconstruction (ASR) as a tool for elucidation of the evolutionary history of functional traits of a protein family have gained strength. Here, we used ASR to trace the evolutionary pathways between mesophilic and thermophilic kinases that participate in the biosynthetic pathway of vitamin B1 in bacteria. By combining biophysics approaches, X-ray crystallography, and molecular dynamic simulations, we found that the thermal stability of these enzymes correlate with their kinetic stability, where the highest thermal/kinetic stability is given by an increase in small hydrophobic amino acids that allow a higher number of interatomic hydrophobic contacts, making this type of interaction the main support for stability in this protein architecture. The results highlight the potential benefits of using ASR to explore the evolutionary history of protein sequence and structure to identify traits responsible for the kinetic and thermal stability of any protein architecture.

Stability, resilienceand eco-evolutionary feedbacks of mutualistic networks to rising temperature.

Ecological networks comprising of mutualistic interactions can suddenly transition to undesirable states, such as collapse, due to small changes in environmental conditions such as a rise in local environmental temperature. However, little is known about the capacity of such interaction networks to adapt to a rise in temperature and the occurrence of critical transitions. Here, combining quantitative genetics and mutualistic dynamics in an eco-evolutionary framework, we evaluated the stability and resilience of mutualistic networks to critical transitions as environmental temperature increases. Specifically, we modelled the dynamics of an optimum trait that determined the tolerance of species to local environmental temperature as well as to species interaction. We then evaluated the impact of individual trait variation and evolutionary dynamics on the stability of feasible equilibria, the occurrence of threshold temperatures at which community collapses, and the abruptness of such community collapses. We found that mutualistic network architecture, that is the size of the community and the arrangement of species interactions, interacted with evolutionary dynamics to impact the onset of network collapses. Some networks had more capacity to track the rise in temperatures than others and thereby increased the threshold temperature at which the networks collapsed. However, such a result was modulated by the amount of heritable trait variation species exhibited, with high trait variation in the mean optimum phenotypic trait increasing the environmental temperature at which networks collapsed. Furthermore, trait variation not only increased the onset of temperatures at which networks collapsed but also increased the local stability of feasible equilibria. Our study argued that mutualistic network architecture interacts with species evolutionary dynamics and increases the capacity of networks to adapt to changes in temperature and thereby delayed the occurrence of community collapses.

Analysis of the influence of temperature on the adsorption characteristics of coal: Insights into low-temperature outburst prevention

To investigate the impact of temperature reduction on the adsorption characteristics of coal gas, isothermal adsorption experiments were conducted with environmental temperature and moisture content as variables. The changing patterns of coal gas adsorption characteristics, adsorption theories, and the temperature response of gas expansion were analyzed. Furthermore, engineering measures for preventing gas outbursts in low-temperature frozen coal seams were discussed. The research findings indicate that the gas adsorption capacity of coal samples increases with decreasing temperature. When the temperature decreases from 20 to −20 °C, the gas adsorption capacity decreases from 34.48 to 19.90 cm3/g. At the same pressure, the adsorption capacity of coal is negatively correlated with temperature. The Langmuir theoretical model better reflects the adsorption law of coal gas under different environmental temperature conditions, wherein the adsorption constant “a” gradually decreases with the increase in environmental temperature. In a closed space, the gas pressure decreases with the decrease in coal sample temperature. Under the new adsorption equilibrium, the gas pressure in the coal sample tank decreases linearly with temperature. Coal samples with different moisture contents exhibit varying degrees of decrease in gas pressure at the same temperature, with higher moisture content resulting in a smaller decrease in gas pressure. Gas expansion energy decreases linearly with the decrease in coal temperature, indicating a proportional relationship between gas expansion energy and coal gas release pressure. As the temperature decreases, the gas pressure decreases. Based on the experimental results, a synergistic approach for preventing gas outbursts through low-temperature freezing is proposed.

Effects of squeezed vacuum field on force sensing for a dissipative optomechanical system

We investigate the force sensing of a mechanical membrane in a dissipative cavity optomechanical system (OMS) driven by a squeezed vacuum field accompanying a strong pump laser. Specifically, the red-detuned laser exhibits a more significant improvement for force sensing compared to the blue-detuned laser. The optimal phase angle contributes to achieving much better force sensing. When injecting a squeezed vacuum field with appropriate squeezing parameter and squeezing phase, the standard quantum limit of force measurement can be easily beaten. Furthermore, the adverse effects of the increase in environment temperature and mechanical damping can be suppressed, simultaneously. This scheme provides a theoretical basics for force sensing of mechanical membranes in dissipative OMS and has potential applications in force feedback control, precision measurement, and force sensor design.

Unveiling the potential of Moringa oleifera Lam. gums: An investigation into optimal tapping strategies

To optimize the best tapping technique for enhanced gum production with minimal injury to the trees, suitable Moringa oleifera Lam. trees were selected for experimentation, and the trees were treated with different tapping techniques for moringa gum production. When gum inducer was applied to trees treated with battery and hand-operated drills with ½ inch drill bit diameter and 1.0 in. drilling diameter, the gum yield was about fifteen times higher than when the inducer was not applied. It was about four times higher for trees treated with hand-operated drills and 1.0 in. drilling diameter. When employing the Gum tapping blazer-75 to develop a blaze, the average gum production was 1.29 times higher than when using a chisel. Bore hole developed with 1.0 in. diameter hand drill with inducer application yielded the highest total gum yield, followed by ½ inch diameter hand drill and ½ inch battery operated drill with inducer application, blaze developed with Gum tapping blazer-75, bore hole developed with 1.0 in. diameter hand drill without inducer application, blaze developed with chisel, bore hole developed with ½ inch hand drill without inducer application, and bore hole developed with battery operated drill having ½ inch drill bit without inducer application, respectively. A regular increasing trend in moringa gum yield was observed almost in all the treatments with an increase in environmental temperature, which indicates that moringa gum can be tapped throughout the year but a higher quantity of gum may be collected during April–September. When employing the Gum tapping blazer-75, blaze is produced on the tree trunk with ease and sharp edges. The use of developed blazer made blazing faster compared with blaze making using chisel. Gum production was higher with gum inducer technology than with any other method when it came to tapping moringa gum from Moringa oleifera trees using a hand drill. Data on quality characteristics determined for engineering can be used as references in development of equipments and machineries for processing and value addition of moringa gum while chemical properties for various applications in food, pharmaceutical and cosmetic industries for development of high value products.

The Feasibility Study of In Situ Conversion of Oil Shale Based on Calcium-Oxide-Based Composite Materia Hydration Exothermic Reaction

Oil shale, as a vast potential resource, is considered an important alternative energy source, and its effective development and economic utilization are of significant importance in alleviating the contradiction between energy supply and demand. Presently, the in situ conversion technology for oil shale has gained significant global attention, with numerous extraction methods undergoing active research and development. One of these methods is the in situ conversion of oil shale based on the hydration reaction of calcium-oxide-based composite material (CaO-CM). This approach harnesses the heat produced by the reaction between CaO-CM and water as a heat source for the pyrolysis of oil shale. This paper conducted experiments to assess the feasibility of temperature associated with this method. The feasibility study mainly includes two aspects: First, it is necessary to investigate whether the temperature generated by the hydration reaction of CaO-CM can meet the temperature requirements for the pyrolysis of oil shale. Through pyrolysis experiments of Xinjiang oil shale, the minimum temperature required for oil shale pyrolysis was determined to be 330 °C. High-temperature and high-pressure reaction vessels were employed to explore the temperature generated by the hydration reaction of CaO-CM. The results show that with the increase in environment pressure, environment temperature, and reaction mass, the maximum temperature generated by the hydration reaction of CaO-CM also increases (reach 455.5 °C), meeting the temperature requirements for the pyrolysis of oil shale. Second, the study evaluates whether the hydration reaction of CaO-CM can induce pyrolysis hydrocarbons of the oil shale. Through the pyrolysis experiments of oil shale based on the hydration reaction of CaO-CM, the changes in the content of pyrolysis hydrocarbons (S2) in oil shale before and after pyrolysis are measured. The results show that under 10 MPa pressure, the content of pyrolysis hydrocarbons in the oil shale decreased from 40.96 mg/g to 0.08 mg/g after pyrolysis. This confirms the feasibility of the temperature conditions for the in situ conversion of oil shale based on the hydration reaction of CaO-CM.

Performance of a deep in situ pressure-preserving coring controller in a high-temperature and ultrahigh-pressure test system

The pressure-preserving controller is the key component of deep in situ pressure-preserving coring (IPP-Coring). With increasing drilling depth, the environmental temperature and pressure increase accordingly. However, due to the strength and sealing problems of pressure-preserving controllers, the coring pressure is generally lower than 70 MPa. Establishing a high-temperature and ultrahigh-pressure test system is highly important for improving the strength and sealing performance of pressure-preserving controllers. This paper introduces a high-temperature and ultrahigh-pressure test system for deep IPP-Coring controller performance analysis. The device includes six parts: an auxiliary air source system, a pressurization system, a temperature control system, a hydraulic system, a data acquisition and electrical control system, and an ultrahigh-pressure vessel. The test system can reconstruct a 150 °C and 200 MPa in situ environment and simulate and test the movement state of the corer and the stability of the pressure-preserving action trigger of the pressure-preserving controller in the deep IPP-Coring process. To verify the performance of this test system, saddle-shaped pressure-preserving controllers made of four different materials were subjected to pressure tests under normal-temperature and high-temperature conditions. The results showed that the ultimate pressure-bearing capability of the pressure-preserving controller greatly varied between normal-temperature and high-temperature conditions. The pressure-preserving ability and sealing performance of the pressure-preserving controller decreased significantly at high temperature, and the pressure-preserving controller exhibited significantly different sealing failure characteristics due to material differences. This study is important for progressing the extraction and evaluation of deep reservoir resources.

Population-specific responses to developmental temperature in the arboviral vector Aedes albopictus: Implications for climate change.

The increase of environmental temperature due to current global warming is not only favouring the expansion of the distribution range of many insect species, but it is also changing their phenology. Insect phenology is tightly linked to developmental timing, which is regulated by environmental temperatures. However, the degree to which the effects of developmental temperatures extend across developmental stages and their inter-stage relationships have not been thoroughly quantified in mosquitoes. Here, we used the mosquito Aedes albopictus, which is an aggressive invasive species and an arboviral vector, to study how developmental temperature influences fitness across developmental stages, thermal traits, energy reserves, transcriptome and Wolbachia prevalence in laboratory-reared populations originally collected from either temperate or tropical regions. We show that hatchability, larval and pupal viability and developmental speed are strongly influenced by temperature, and these effects extend to wing length, body mass, longevity and content of water, protein and lipids in adults in a population-specific manner. On the contrary, neither adult thermal preference nor heat resistance significantly change with temperature. Wolbachia density was generally lower in adult mosquitoes reared at 18°C than at other tested temperatures, and transcriptome analysis showed enrichment for functions linked to stress responses (i.e. cuticle proteins and chitin, cytochrome p450 and heat shock proteins) in mosquitoes reared at both 18 and 32°C. Our data showed an overall reduced vector fitness performance when mosquitoes were reared at 32°C, and the absence of isomorphy in the relationship between developmental stages and temperature in the laboratory population deriving from larvae collected in northern Italy. Altogether, these results have important implications for reliable model projections of the invasion potentials of Ae. albopictus and its epidemiological impact.

Tetraploid wheat (Triticum turgidum) lines from the United States as a source of Hessian fly (Mayetiola destructor) resistance

AbstractDeploying resistant wheat cultivars is the most economical and environment‐friendly strategy to manage the devastating effects of the dipteran pest, Hessian fly (Hf; Mayetiola destructor). Currently, 37 Hf resistance genes have been identified to combat the 18 Hf genotypes documented so far. However, the Hf populations adapt rapidly to overcome the newly deployed resistance genes within a few years of release resulting in development of virulent Hf biotypes and breakdown of plant resistance. Identification of new and novel sources of resistance offers breeders additional resources that can be included in the breeding programmes to develop elite Hf‐resistant cultivars. In the current study, we screened 374 wheat (tetraploid and hexaploid) accessions originating from different regions of the United States and identified three tetraploid (Triticum turgidum) pasta wheat lines, one originating from North Dakota (PI 639869) and two from Minnesota (PI 352398 and CItr 15710) exhibiting ≥95% resistance to Hf biotype L at 20°C. Further, the wheat cultivar PI 352398 showed 100% resistance to six additional Hf genotypes including biotypes B, C, D, O, GP and vH13. The lines PI 639869 and CItr 15710 also showed &gt;70% resistance with most biotypes, except against biotype GP with the former and biotype B with the latter. Interestingly, a few plants from these two cultivars exhibited putative tolerance to these biotypes where the plants showed normal growth but harboured white, live larvae and showed cell permeability that was intermediate in levels between Hf‐infested resistant and susceptible wheat. Additionally, since the increase in environmental temperatures to 25–30°C also negatively impacts Hf resistance, the three T. turgidum (PI 639869, PI 352398 and CItr 15710) cultivars were evaluated for Hf resistance at 30°C. None of the wheat cultivars were resistant to Hf biotype L at 30°C indicating a temperature‐dependent breakdown of resistance and are therefore not suitable for geographical regions with higher environmental temperatures. Taken together, these three wheat lines represent additional sources of Hf resistance that can be leveraged by breeders for developing durable elite lines.

Linear modeling analysis of the heat balance of the transmission line in high frequency critical ice melting state

Abstract The icing of transmission lines can cause many problems such as increased line load, unbalanced tension, and galloping, posing a serious threat to the reliable operation of the power system. Therefore, linear modeling analysis of the heat balance under a high-frequency critical ice melting state of transmission lines is studied. The thermal conduction states of melting, heating, twisting, rotating melting, and ice layer detachment of ice melting conductors are analyzed. Based on the heat conduction process of thermal melting of ice on transmission lines, a simplified calculation formula for thermal melting ice time is derived to calculate times for heating, ice layer torsion, and air gap increase. At the same time, based on the law of conservation of energy, thermodynamic boundary conditions for iced conductors were established and corresponding physical models were constructed. Based on this model, we conduct a linear modeling of the heat balance in the melting state in order to provide a more accurate prediction of temperature distribution. The experimental results show that there is a negative correlation between environmental temperature and critical melting current, and the melting time decreases with the increase of environmental temperature.

THE MECHANICAL PROPERTIES AND FAILURE MODE OF SIMULATED LUNAR ROCK BY IN SITU TEMPERATURE REAL-TIME ACTION OF LUNAR-BASED

To achieve in situ condition-preserved coring of the lunar surface and deep lunar rocks and a return mission, it is necessary to explore the mechanical properties and failure modes of simulated lunar rocks that have physical and mechanical properties approximately equivalent to those of mare basalt under simulated lunar temperature environments ([Formula: see text][Formula: see text]C to 200[Formula: see text]C). To this end, real-time uniaxial compression tests were conducted on simulated lunar rocks under corresponding in situ temperature conditions, and the mechanical properties, deformation characteristics, micromorphology, and failure modes were analyzed. Based on the macroscopic analysis, as the environmental temperature decreases, the uniaxial compressive strength, peak strain, and peak strain duration of simulated lunar rocks exhibit a nonlinear increasing trend, with maximum increases of 33.00[Formula: see text], 36.16[Formula: see text], and 49.25[Formula: see text] from those at room temperature, respectively. Based on microscopic analysis, the intergranular fractures run through the entire samples under the environmental temperature. As the environmental temperature increases, intergranular and transgranular fractures coexist, and layered fractures appear at high temperatures. At the same time, some samples exhibit undulating and stepped morphologies caused by shear stress. For the fractal dimension of a simulated lunar rock main fracture surface, the fractal dimension of the actual angle and the corrected angle increase first and then decrease with increasing environmental temperature, and the maximum error of the two is only 1.84[Formula: see text]. The overall fractal dimension ranges from 2.02 to 2.28, and the fractal dimension under real-time high-temperature conditions is higher than that under real-time low-temperature conditions. In addition, the failure mode of the simulated lunar rocks under real-time in situ temperature changes is a combined tensile–shear failure mode with shear failure (primary) and tensile failure (secondary). The above research results are expected to be applied to in situ condition-preserved coring in extreme lunar environments and provide a scientific basis for the design and development of in situ condition-preserved coring robot systems for the extreme environment of deep space.

Experimental study on refrigeration system performance of pure electric refrigerator car based on medium pressure air supply

In view of the low refrigeration efficiency of the refrigeration system of the pure electric logistics car under the high temperature environment, an experimental platform of the refrigeration system based on medium pressure air supply of the pure electric refrigerator car was built with R404A as the refrigerant, the experiment results show that the system refrigerating capacity, COP and EER decrease with the increase of external environment temperature under the same internal environment temperature, the compressor power and exhaust temperature increase with the increase of the external environment temperature. When the external environment temperature is 43 °C, the medium pressure air supply technology is obviously better than the non-air supply technology, the refrigerating capacity increased by 4.1–12.73 %, the compressor power and EER changed little, the COP increased by 1.3–6.38 %, and the exhaust temperature reduced by 3.4 °C-7.11 °C, especially at -3 °C, the system refrigerating capacity decreases by 30.1 %, the compressor power increases by 35.6 %, the COP and EER distribution decreases by 51.24 % and 42.68 %.

Resolving 3D microstructure evolution of ceramifiable composites at elevated temperatures using in-situ X-ray computed tomography

Ceramifiable polymer composites suffers significant microstructure change during the polymer-to-ceramic conversion as the environmental temperature increases. The present study employs in-situ X-ray computed tomography (XCT) to reveal the microstructure evolution of high-silica/boron-phenolic composites modified with B4C and talc (B4C-talc_HSF/BPR) in three dimensions as the composites is heated to 1000 °C. The cracks are classified based on their locations, and the temporal sequence of their formation is identified. The evolution of internal pore distribution is reconstructed and analyzed quantitatively. Furthermore, the 3D deformation fields of composites during in-situ heating were calculated using digital volume correlation. It is found that the equivalent strain along the thickness direction shows a multi-stage behavior corresponding to the thermal degradation and ceramization transformation processes. The findings provide a 3D visualization of crack propagation and deformation during the polymer-to-ceramic conversion process, which can provide a foundation for further developments in material design.

Geography and developmental plasticity shape post-larval thermal tolerance in the golden star tunicate, Botryllus schlosseri

Local adaptation and phenotypic plasticity play key roles in mediating organisms’ ability to respond to spatiotemporal variation in temperature. These two processes often act together to generate latitudinal or elevational clines in acute temperature tolerance. Phenotypic plasticity is also subject to local adaptation, with the expectation that populations inhabiting more variable environments should exhibit greater phenotypic plasticity of thermal tolerance. Here we examine the potential for local adaptation and developmental plasticity of thermal tolerance in the widespread invasive tunicate Botryllus schlosseri. By comparing five populations across a thermal gradient spanning 4.4° of latitude in the northwest Atlantic, we demonstrate that warmer populations south of the Gulf of Maine exhibit significantly increased (∼0.2 °C) post-larval temperature tolerance relative to the colder populations within it. We also show that B. schlosseri post-larvae possess a high degree of developmental plasticity for this trait, shifting their median temperature of survival (LT50) upwards by as much as 0.18 °C per 1 °C increase in environmental temperature. Lastly, we found that populations vary in their degrees of developmental plasticity, with populations that experience more pronounced short-term temperature variability exhibiting greater developmental plasticity, suggesting the local adaptation of developmental plasticity. By comparing the thermal tolerance of populations across space and through time, we demonstrate how geography and developmental plasticity have shaped thermal tolerance in B. schlosseri. These results help inform our understanding of how species are able to adjust their thermal physiology in new environments, including those encountered during invasion and under increasingly novel climate conditions.

The influence of heat stress on the antioxidant protection glutathione link and the content of lipid peroxidation products in chicken liver

Heat stress is one of the main reactions of the body’s response to environmental factors, negatively affecting the welfare of various animal species. An increase in environmental temperature can cause stress, which, in turn, potentially has various negative consequences for animals including disruption of the antioxidant system functioning. Violating the antioxidant-prooxidant balance can lead to an increased free radicals formation in the body, which can damage cells and promote the development of various diseases. The article presents the study results of the artificially simulated heat stress effect on individual indicators of the antioxidant system and lipid peroxidation products in the chickens’ liver. The choice of these animals for this study is due to the fact that the poultry is particularly sensitive to the elevated environmental temperatures and, accordingly, to heat stress. This is caused by the biological peculiarities of birds, in particular, they lack sweat glands, and their body surface is mostly covered with feathers, which, together with the high density of keeping in the industrial poultry farming, often leads to the heat stress. The purpose of this work was to find out the presence or absence of changes in individual indicators of the antioxidant system glutathione link and the lipid peroxidation products content in chickens’ liver. The analysis of indicators such as lipid hydroperoxides (LOOH), TBA-active products, reduced glutathione (GSH), glutathione peroxidase (GSH-Px) and glutathione reductase (GR) will allow us to obtain information about the body’s antioxidant defense system state and the oxidative stress level under heat stress conditions. In this study we used 18 hens of the white Leghorn breed. The research was conducted in the vivarium of the Institute of Animal Biology of the National Academy of Sciences in two stages. During the first stage, chickens were kept at an air temperature of 20°С for 7 days. During the second stage, we created heat stress conditions by increasing the temperature to 35°С 6 hours a day, also for 7 days. It has been found that as the ambient temperature increased, the content of LOOH, GSH, and activity of GSH-Px in the liver of chickens increased (P&lt;0.01), while, on the contrary, the content of TBA-active products and activity of GR decreased (P&lt;0.01). The obtained data prove the heat stress effect on the antioxidant protection glutathione link in chicken liver. Research results can be of practical value for improving the bird keeping conditions in the industrial poultry farming, developing strategies for protection against stress, and improving the conditions to ensure the animals’ welfare and health.