Drastic Temperature Changes Research Articles

Observation of the microstructure and shape of self-healing microvascular in asphalt

Microvascular containing rejuvenator is a promising smart material for self-healing asphalt of pavement. The objective of this work was to experimentallyobserve the shape and state of self-healing microvascular in asphalt. Polyvinylidene fluoride (PVDF) microvascular containing oily rejuvenator was spun through single-wet-spinning method. Thermogravimetry analysis (TGA) and scan electron microscopy (SEM) morphology results proved that microvascular can endure 300 °C high temperature in asphalt and maintain its own stability. At the same time, the microvascular can withstand drastic temperature changes while still maintaining its integrity. Micro-XCT image indicated no debonding phenomenon was found between the microvascular and bituminous binder. Oily rejuvenator can be safely stored in the microvascular without being affected. At the same time, 3D micro-XCT image showed that the microvascular did not have any entanglement or breakage even under the extrusion of the aggregates. Microvasculars were randomly distributed isotropically in the asphalt. By comparing the shape of long microvascular and short microvascular in asphalt, it is found that short one is more suitable for asphalt. Possible shapes were observed through micro-XCT slides named as C-shape, L-shape, O-shape, S-shape, and V-shape. Microvasculars were squeezed by the aggregate in the asphalt, which deformed and became deflated. However, microvascular remained intact and no breakage occurs. Oily rejuvenator was safely protected in the microvascular. The above intuitive image data are evidence proving that the microvascular containing rejuvenator will be a feasible approach to realize the self-healing and self-rejuvenating process of asphalt.

Thermal Design Rules of AlGaN/GaN-Based Microwave Transistors on Diamond

Reliable operation of high power GaN amplifiers at maximum performance relies on the mutual optimization of several design parameters constrained by a defined thermal budget. On high thermal conductivity, substrates, such as SiC and diamond, undergo small changes within the design that can lead to drastic changes in channel temperature. We utilize finite element simulations to provide design rules for device structures for GaN-on-diamond amplifiers, benchmarked against GaN-on-SiC. At 8 W/mm power density, a 13 μm gate pitch GaN-on-diamond design compared to a commonly employed 40 μm gate pitch GaN-on-SiC design results in ~40 °C and ~20 °C cooler peak channel temperature, i.e., 182 °C for single and 201 °C for polycrystalline diamond (PCD) substrates despite the 3× larger areal power density. The simulations were validated with 1.25 mm wide, 10-finger GaN-on-diamond high-electron-mobility transistors (HEMT) devices of 13 and 40 μm gate pitch, with good electrical performance in pulsed I-V measurements and Raman thermography measurements. The commonly used Au-Sn die-attach is determined as the next limiting factor for GaN-on-Diamond technologies which require the development of new die-attach materials.

Antioxidant effect of Elamipretide on bull's sperm cells during freezing/thawing process.

Spermatozoa are subjected to drastic changes in temperature, ice crystal formation, and diverse types of stresses (chemical, physical, osmotic, and oxidative) during the cryopreservation process, which severely compromise sperm quality and fertility. In this study, we aimed to investigate the protective role of Elamipretide in the cryopreservation of bull's spermatozoa. The study included 36 healthy Simmental bulls with an average age of 2±0.5years housed individually in pens. Two ejaculates were collected from each bull using an artificial vagina at 7 a.m. Subsequently, the semen was extended with animal protein-free commercial BIOXcell® extender (IMV Technologies) to a final concentration of 160×106 spermatozoa/ml, and rated in terms of motile sperm percentage, progressive motility, viability, and morphological abnormality of spermatozoa. Semen samples that showed more than 60% motility and 60% viability, were selected for the experiment. The fresh semen was then divided into five equal fractions. The first fraction was left for the control group (without Elamipretide), to the next were added in succession 0.1; 1; 5; and 10μM of Elamipretide TFA (Trifluoroacetic) (MedChemExpress). After that semen was subjected to freezing and thawing. Next semen was assessed for motility, viability, mitochondrial membrane potential and acrosome integrity, and antioxidant activity (SOD, CAT, MDA). It has been shown that a concentration of 5 and 10μM proved to be the most effective in terms of tested parameters of the quality of sperm cells subjected to cryopreservation. In conclusion, addition of the Elamipretide to the cryopreservation extender significantly improved frozen-thawed sperm cells quality and their function. The results of this study indicate that Elamipretide can be used as a cryoprotective agent to protect cells against the devastating effects of oxidative stress and increasing sperm survival after cryopreservation.

Complete chloroplast genome sequencing of ten wild Fragaria species in China provides evidence for phylogenetic evolution of Fragaria

Complete chloroplast genomes of ten wild Fragaria species native to China were sequenced. Phylogenetic analysis clustered Fragaria species into two clades: The south clade (F. iinumae, F. chinensis, F. pentaphylla, F. nilgerrensis, F. daltoniana, F. corymbosa, F. moupinensis, F. tibetica, F. nipponica, F. gracilis, and F. nubicola and north clade (F. viridis, F. orientalis, F. moschata, F. mandshurica, F. vesca, F. chiloensis, F. virginiana, and F. × ananassa), while F. iinumae is the oldest extant species. Molecular clock analysis suggested present Fragaria species share a common ancestor 3.57 million years ago (Ma), F. moschata and octoploid species evolve 0.89 and 0.97 Ma, respectively, but F. moschata be not directly involved in current octoploid species formation. Drastic global temperature change since the Palaeocene–Eocene, approx. 55 Ma, especially during uplifting of the Qinghai-Tibet plateau and quaternary glaciation may have driven the formation of Fragaria, separation of two groups and polyploidization

Wind-envelope interaction as the origin of the slow cyclic brightness variations of luminous blue variables

Luminous blue variables (LBVs) are hot, very luminous massive stars displaying large quasi-periodic variations in brightness, radius, and photospheric temperature on timescales of years to decades. The physical origin of this variability, called S Doradus cycle after its prototype, has remained elusive. We study the feedback of stellar wind mass-loss on the envelope structure in stars near the Eddington limit. We calculated a time-dependent hydrodynamic stellar evolution, applying a stellar wind mass-loss prescription with a temperature dependence inspired by the predicted systematic increase in mass-loss rates below 25 kK. We find that when the wind mass-loss rate crosses a well-defined threshold, a discontinuous change in the wind base conditions leads to a restructuring of the stellar envelope. The induced drastic radius and temperature changes, which occur on the thermal timescale of the inflated envelope, in turn impose mass-loss variations that reverse the initial changes, leading to a cycle that lacks a stationary equilibrium configuration. Our proof-of-concept model broadly reproduces the typical observational phenomenology of the S Doradus variability. We identify three key physical ingredients that are required to trigger the instability: inflated envelopes in close proximity to the Eddington limit, a temperature range where decreasing opacities do not lead to an accelerating outflow, and a mass-loss rate that increases with decreasing temperature, crossing a critical threshold value within this temperature range. Our scenario and model provide testable predictions, and open the door for a consistent theoretical treatment of the LBV phase in stellar evolution, with consequences for their further evolution as single stars or in binary systems.

Trend Analyses of Baseflow and BFI for Undisturbed Watersheds in Michigan—Constraints from Multi-Objective Optimization

Documenting how ground- and surface water systems respond to climate change is crucial to understanding water resources, particularly in the U.S. Great Lakes region, where drastic temperature and precipitation changes are observed. This study presents baseflow and baseflow index (BFI) trend analyses for 10 undisturbed watersheds in Michigan using (1) multi-objective optimization (MOO) and (2) modified Mann–Kendall (MK) tests corrected for short-term autocorrelation (STA). Results indicate a variability in mean baseflow (0.09–8.70 m3/s) and BFI (67.9–89.7%) that complicates regional-scale extrapolations of groundwater recharge. Long-term (>60 years) MK trend tests indicate a significant control of total precipitation (P) and snow- to rainfall transitions on baseflow and BFI. In the Lower Peninsula Rifle River watershed, increasing P and a transition from snow- to rainfall has increased baseflow at a lower rate than streamflow; an overall pattern that may contribute to documented flood frequency increases. In the Upper Peninsula Ford River watershed, decreasing P and a transition from rain- to snowfall had no significant effects on baseflow and BFI. Our results highlight the value of an objectively constrained BFI parameter for shorter-term (<50 years) hydrologic trend analysis because of a lower STA susceptibility.

The effect of printing velocity on the temperature and viscosity of the polymer thread at the nozzle exit in 3D printers

Fused Deposition Modelling (FDM) is a powerful method for advanced additive manufacturing of polymeric materials, due to its simplicity and low cost. However, the process implies complex phenomena which are not fully understood yet. In particular, the effect of viscosity on the printed thread is a key parameter to control if good quality products are to be obtained. Experimental data of two grades of acrylonitrile-butadiene- styrene copolymer (ABS) was employed to analyse, by using ANSYS Fluent simulation package, six printing velocities at a temperature of 230°C. A drastic temperature change was observed as the printing velocity increases, confirming the effect of viscosity on the shear created on the wall of the nozzle transversal to the printing bed. The polymers analysed present different viscosity behavior even under the same angular frequency range (0.1 to 100 rad/s), and testing temperature (230°C), which could lead to inhomogeneities. Our results allow taking into account these parameters as part of the design criteria.

Development of Engineering Qualification Model of a Small ETG for a Launch Environmental Test

According to the development plan for the Korea Space Launch Vehicle, a performance verification satellite will be installed in the launch vehicle in 2021. In addition, three payloads, including a small electrically heated thermoelectric generator (ETG), will be developed and installed in the satellite. In particular, a small ETG has been developed by the Korea Atomic Energy Research Institute for the purpose of evaluating the characteristics of the ETG in the space environment prior to the development of a radioisotope thermoelectric generator for lunar missions. In this study, shock and vibration tests were carried out to check whether the ETG can endure the launch environment of the spacecraft. In addition, a thermal cycle test and a thermal vacuum test were conducted to check whether the ETG maintains its performance, even at drastic temperature changes, which can be applied to the ETG in space. Finally, a periodic performance test was carried out to measure the degradation level of the small ETG.

Review of Climate Change Impacts on Human Environment: Past, Present and Future Projections

Climate changes are one of the most significant aspects, which cause a threat to all human beings living on the planet Earth. Climate changes could happen due to both natural internal processes and external forcing, or due to persistent anthropogenic changes. The identified drastic temperature changes, increase in the emitted greenhouse gasses, and sea-level changes as witnessed from the acquired data; such as from ice cores, during the past centuries and even decades are all due to climate changes. Due to the increase in the emitted greenhouse gasses, major sectors in the Earth will be hit severely, such as agriculture and industry. Human welfare and health services will consequently suffer and development, in general, is going to be hampered. Large parts of the Earth will be unfavorable for living due to different reasons; such as inundation by seawater, decrease in temperature; however, some scientists believe that the increase in the percentages of the emitted greenhouse gasses has decreased or delayed the possibility of starting a new ice age. We have presented all possible scenarios, which may happen due to climate changes including temperature changes, emitted greenhouse gasses, sea level, and other harsh effects not only on human beings but all other living animal and plant species.

A Snake Falls to Earth by Darcie Little Badger

Reviewed by: A Snake Falls to Earth by Darcie Little Badger Natalie Berglind Little Badger, Darcie A Snake Falls to Earth. Levine Querido, 2021 [384p] Trade ed. ISBN 9781646140923 $18.99 Reviewed from digital galleys R Gr. 7-10 When Nina’s great-great-grandmother dies, she passes on a story that the translator app on Nina’s phone can’t interpret. Since Nina has grown up compiling dictionaries of indigenous languages, she has the skill to piece the tale together, and she realizes it’s about the animal people. Concurrently, in the Reflecting World, Oli is a cottonmouth person on his own for the first time, swept up in the antics of an alligator woman, a bounty hunter bear, and two mischievous yet friendly coyote sisters. Because the animal people are connected to their species on Earth, when Oli’s toad friend Ami gets sick, it indicates the extinction of his Earth species, so Oli travels to Earth to seek help, finding understanding in Nina and her family. As in the case with Little Badger’s debut Elatsoe (BCCB 9/20), main character Nina is, like the author herself, Lipan Apache. The climate change happening in Texas in the novel, with its hurricanes, flash floods, and tornadoes, will be a close subject to those who have recently experienced drastic temperature change and flooding in their own lives; Little Badger maintains an effective balance between the magic of the animal people’s holding a tornado at bay and the futility of undoing years of damage to the planet. The take on technology is interesting and modern, with Nina attempting to win beaucoup bucks from a video-based app with a staged bear attack and using her translator app to crack a dying language. The baddie is a little predictable, but it’s made up for by a more realistic ending that exhorts people with the millions to influence climate change and turn the tide. Copyright © 2021 The Board of Trustees of the University of Illinois

A temperature drift compensation method applied to fiber optic gyroscope north-seeking

The startup error of fiber optic gyroscope (FOG) in north-seeking is the error caused by the zero-bias drift of FOG caused by drastic change of the temperature in the starting process. The start-up error significantly increases north-seeking error during the cold startup phase compared to the stable phase, which prolongs the effective north-seeking time. Through the analysis of the factors affecting the temperature drift of FOG, the mul-ti-parameter linear model was established by empirical mode decomposition (EMD), autoregressive-moving average (ARMA) modeling and Kalman filtering to realize a temperature drift compensation method applied to FOG north-seeking. The experimental results show that the method can reduce the north-seeking startup error by nearly 80%, so that the startup north-seeking precision is equivalent to the stable phase and the effective north-seeking time is shortened.

A universal scale inhibitor: A dual inhibition/dispersion performance evaluation under difficult brine stresses

Scale inhibition is of crucial importance in harvesting geothermal energy, an attractive, renewable and sustainable energy source. The majority of the geothermal reservoir waters around the world contain a variety of anions and cations, which are prone to inorganic precipitation when subjected to drastic changes in both temperature and pressure, causing failures and unwanted shut-downs. Our goal is to prevent the formation, precipitation and deposition of such scales by stabilizing their respective components. Herein, the ability of a methacrylate-structured, grafted co-polymer, coined PEGPHOS-LOW (with polyethylene glycol and phosphonate grafts), to control inorganic precipitation is evaluated for four artificial geothermal brines of variable scaling propensity towards common geothermal scales, such as amorphous silica, magnesium, aluminum and iron silicates, zinc, lead and iron sulfides and calcium carbonate. Inhibitor selection was based on previous results obtained with four, similar inhibitor grafted co-polymers (one containing only polyethylene glycol, PEG, one with only phosphonate grafts, and two containing variable ratios of both grafts) against individual scales. The working brines were designed based on the saturated conditions of geothermal well fluids. PEGPHOS-LOW is a polymer that contains 34 PEG20 grafts, and 14 phosphonate grafts. It is a dual scale control additive, as it can function both as a scale inhibitor (keeping the scaling species soluble) and as a dispersant (keeping the scale particles formed in a suspended form). It displays a dosage-dependent scale inhibition and dispersion behavior, however, very high concentrations are necessary for satisfactory effectiveness, due to the high scaling propensity of the brines.

Temperature field simulation and mechanical property study of directed laser depositing thin-walled Inconel 718

Directed laser deposition (DLD) has become a popular forming method however it is a process with drastic temperature changes, during which the temperature accumulation effect easily causes deposition defects. Wherein the selection of the process parameters could affect the shape quality and mechanical property of the formed parts. This work investigates the distribution characteristics of the temperature field in the DLD process by finite element (FE) method and derives the temperature-time curves of special nodes which show good agreement with corresponding experimental tests. Moreover, the influence of laser power, scanning speed, and substrate initial temperature on temperature field is also studied. Based on the validation of simulation and analyses of forming defects, Inconel 718 thin-walled part with good shape was prepared by adapting the strategy of changing laser power for different layers. The formed part characterizes the finer microstructure compared with the casting part. The dendrite direction in the molten pool is mainly perpendicular to the bottom of the molten pool, and it grows epitaxially along the direction of heat flow. Besides, the mean tensile strength and elongation of the formed thin-walled part, to a certain extent, show anisotropy in the parallel and vertical direction to depositing, respectively.

Impact of Climate Change on Olive Crop Production in Italy

The effects of climate change on agricultural systems raise important uncertainties about the future productivity and suitability of crops, especially in areas suffering from intense environmental changes. Olive groves occupy Mediterranean areas characterized by seasonal temporary droughts, which cause this cultivation to be highly dependent on local microclimatic conditions. Olive crop production can be reliably estimated using pollen intensity metrics together with post-pollination environmental conditions. In this study, we applied this kind of statistics-based models to identify the most relevant meteorological variables during the post-pollination periods for olive fruit production. Olive pollen time-series for the period of 1999–2012 was analyzed in 16 Italian provinces. Minimum and maximum temperature during spring and summer (March–August) showed a negative relationship with olive production, while precipitation always showed a positive correlation. The increase in aridity conditions observed in areas of Italy during the summer represents an important risk of decreasing olive crop production. The effect of climate change on the olive production trend is not clear because of the interactions between human and environmental factors, although some areas might show an increase in productivity in the near future under different climate change scenarios. However, as more drastic changes in temperature or precipitation take place, the risk to olive production will be considerably greater.

Development of Techniques about Production of Recombinant vaccines and cells with Activated Immunogenic potential

Methods about derivation of myeloid-like and lymphoid-like cells from normal embryonic fibroblasts were developed and tested. Balb/c mice normal mouse embryonic cells from line 3T3 were co-cultivated with mouse malignant myeloma cells, containing inserted. Murine Leukemia Virus (MuLV) (with RNA-genome, Retroviridae family). For this goal, separate subpopulation of normal mouse embryonic fibroblasts were pre-incubated in cultural fluid, supplemented by previous incubation of myeloma cells in it, after subsequent centrifugation and filtration. Other sub-populations of 3T3 cells were co-cultivated with myeloma cells, by addition of cultural fluids plus cellular suspensions of both types. Subsequently, all mixed cultures were freezed after addition of cryo-protector Dimethylsufoxide (DMSO), subsequently thawed and re-incubated in standard laboratory conditions. In the cultures, pre-incubated in cultural fluid, supplemented by previous incubation of mouse malignant myeloma cells, cells in different stages of myeloid/phagocyte and lymphoid/plasmatic cell differentiation were observed, but in addition of suspensions of cells from both types, appearance of hybrid cells of myeloid-like and phagocyte-like, as well as of lymphoid-like and plasmatic cells-like with mouse malignant myeloma cells were noted. The established changes could be explained with the eventual existence of capable to differentiate to various lineages stem-like cellular sub-populations in the general 3T3 cell line. Also, activated fusion between different cells, as well as between cells and viral particles on the influence of DMSO and of the drastic temperature changes was proposed, which could also lead to transfer of nucleotide sequences. On this principle, a possibility for production of recombinant viral vaccines by exchange of nucleotide sequences between cells and viral particles could be suggested. Furthermore, in confirmation of the literature findings, a capability of non-myeloid and non-lymphoid cells to produce membrane receptor glycoproteins was proposed.

Potential vegetable crops – need for exploration and conservation for nutritional security for rural livelihoods

Underexploited vegetables are known to play a major role in the nutritional livelihood of the Indian population especially in the rural areas where people cannot pay for meat, egg and milk. They are minor, neglected potential crops but not fully exploited for nutritional security, health, poverty alleviation and providing daily diet. In the face of threats posed by climate change as exemplified by drastic changes in rainfall pattern, temperature, relative humidity, radiation, weeds-pests-diseases complex and general alterations in the trends of climatic elements, there is the need to discuss the future of the uncultivated but edible plant species which have served as basis of livelihood for the poor people over several years. Underexploited vegetable crops have many uses like quick, easy to grow and hardy in nature, these crops tolerate adverse climatic and soil conditions, they are a nutritionally rich source of vitamins, minerals, carbohydrates, protein, fats and protect from malnutrition deficiency disease in poor rural children mainly under the age limit of 3-4 years in India. Underexploited vegetable crops have a long history of local consumption and people are aware about their nutritional and medicinal properties. These are cheap and readily available. Cultivation of these crops is restricted to specialized geographical regions mainly by poor farming communities which derive their sustenance and livelihood from such plants. Evidently, these crops of widely consumed nutritious vegetables have been relatively neglected in research and conservation. In India 47% of children below the age of three years are malnourished or underweight, out of a global estimated total of 146 million, south Asia has the highest rates. Presently most of the research work is focused on more popular vegetables like tomato, chili, watermelon, cucumber, cauliflower, cabbage, carrot, etc. Minor work is done on improvement of these underutilized vegetables. However, some preliminary work was carried out on improvement of these future vegetables and cultivars developed are discussed under different groups such as underutilized cucurbits, minor legumes, less leafy vegetables, solanaceous vegetables, tree vegetables and underutilized cole crops. This paper therefore discusses the diversity of underexploited vegetables in India by taking into account the available species, the uses, the mode of exploitation and the role that extension education can play in bringing these crops into cultivation, especially in this era of climate change in order to prevent them from extinction and provide nutritional security to rural people.

What Makes the Wood? Exploring the Molecular Mechanisms of Xylem Acclimation in Hardwoods to an Ever-Changing Environment

Wood, also designated as secondary xylem, is the major structure that gives trees and other woody plants stability for upright growth and maintains the water supply from the roots to all other plant tissues. Over recent decades, our understanding of the cellular processes of wood formation (xylogenesis) has substantially increased. Plants as sessile organisms face a multitude of abiotic stresses, e.g., heat, drought, salinity and limiting nutrient availability that require them to adjust their wood structure to maintain stability and water conductivity. Because of global climate change, more drastic and sudden changes in temperature and longer periods without precipitation are expected to impact tree productivity in the near future. Thus, it is essential to understand the process of wood formation in trees under stress. Many traits, such as vessel frequency and size, fiber thickness and density change in response to different environmental stimuli. Here, we provide an overview of our current understanding of how abiotic stress factors affect wood formation on the molecular level focussing on the genes that have been identified in these processes.

Rolling paths design assisted by target-temperature driven intelligent FE simulation of radial-axial ring rolling

The microstructures of hard-to-deform materials such as titanium alloy are very sensitive to temperature change in hot working process. During ring rolling process, unreasonable rolling paths will lead to drastic temperature change in local region of ring, thus damaging the microstructure and performance of rolled ring. This work proposes a method for designing the rolling paths which could accurately control the ring temperature by target-temperature driven intelligent FE simulation. The main idea of target-temperature driven intelligent simulation is introduced. An intelligent 3D-FE model for TA15 titanium alloy ring rolling is established under ABAQUS/Explicit environment. The rolling paths under different initial conditions are obtained by intelligent FE simulations. The influence rule of initial conditions on rolling paths is revealed. The temperature control effects and change under different initial conditions are discussed. Considering the temperature control effects, a feasible range of initial ring temperature is suggested. Using the proposed method, the quick and accurate design for the rolling paths in radial-axial ring rolling process is realized. It is of great significance for the design and optimization of rolling paths and the accurate regulation of ring temperature in actual production.

Drastic tailorable thermal expansion chiral planar and cylindrical shell structures explored with finite element simulation

Design of materials and structures with quite low coefficient of thermal expansion (CTE), even zero or negative CTE is important for industrial application where drastic temperature changes are encountered. In this paper, making use of the bending of bi-material beam and the unique deformation mechanism of chiral lattice structures, five sets of chiral lattice composite structures with tailorable CTEs are proposed, where synergic effects of rigid node rotation and bi-material ligament bending deformation are responsible for giant range of structural deformation due to temperature change, from positive CTE to negative CTE through adjusting the geometrical parameters of composite bi-material chiral unit cell, and the relationship between unit cell geometric parameters and CTEs of the structure are studied systematically through finite element analysis. Finally, design of bi-material cylindrical shells consisting of anti-tetra chiral unit cells are proposed, and its axial CTEs with different number of the unit cells along the circumferential are studied systematically, demonstrating the robust range of CTEs can be generated through adjusting the geometrical parameters of chiral bi-material unit cells. The proposed chiral structures demonstrated promising application potentials in industrial fields, such as: aerospace and microelectronics, where extremely high structural accuracy is required during harsh working temperature environment.

Cellular and epigenetic changes induced by heat stress in bovine preimplantation embryos.

Exposure of the preimplantation embryo to heat stress triggers a series of cellular, molecular, and adaptive changes preventing a normal embryonic development. Heat stress disrupts the embryo cytoskeleton, intracellular calcium levels, mitochondrial function, and induces apoptosis. Moreover, heat stress can act indirectly through induction of reactive oxygen species (ROS), leading to a variety of cellular damage. Embryonic resistance to heat shock is determined by factors such as genotype, developmental stage, apoptosis, redox status, and regulatory molecules. The early embryo is very susceptible to heat stress; it acquires resistance to elevated temperature as development advances. One of the mechanisms involved in the developmental acquisition of thermotolerance is heat-induced apoptosis, which acts as a quality control mechanism to remove damaged blastomeres allowing the embryo to survive after stress. Although embryos at >8-cell stage can activate the apoptotic cascade as an adaptive response to stress, embryos at the two-cell stage are resistant to proapoptotic signals. This lack of apoptotic response has been associated to mitochondrial resistance to depolarization and epigenetic regulations, such as DNA methylation and histone deacetylation. Even though the cellular mechanisms triggered by heat stress have been studied, very little attention has been paid to the vulnerability of the epigenome to drastic temperature changes during the preimplantation period. Therefore, this review aims to characterize the effects of elevated temperature on the bovine embryo, especially addresissing developmental, cellular, and epigenetic alterations triggered in response to temperature.