Hardness and Texture of Electrolytic Copper Processed by ECAP at Ambient and Warm Temperature

Among several severe plastic deformation (SPD) methods, the Equal Channel Angular Pressing (ECAP) process is one of the most popular. This process's main characteristic is producing materials with ultra-fine or nanometric grains. Due to these microstructural changes, it is possible to improve mechanical properties such as strength and ductility. In this perspective, the aim of the present work was to evaluate the variations of the mechanical hardness property associated with microstructural and textural changes of pure copper as a function of its processing by SPD via ECAP. For this, the material was submitted to four passes through routes A (the sample is repetitively pressed without any rotation between each pass) and Bc (the sample is rotated in the same sense by 90° between each pass) at cold and warm temperatures. Through the obtained result, it was verified that the ambient temperature of the Bc route was the one that promoted greater homogeneity in the microstructure and weakening of the texture after the fourth pass. On the other hand, warm processing of copper by ECAP promoted a softening of the samples and a homogeneous distribution of hardness in both routes.

Roles of plant hormones in thermomorphogenesis

Global warming has great impacts on plant growth and development, as well as ecological distribution. Plants constantly perceive environmental temperatures and adjust their growth and development programs accordingly to cope with the environment under non-lethal warm temperature conditions. Plant hormones are endogenous bioactive chemicals that play central roles in plant growth, developmental, and responses to biotic and abiotic stresses. In this review, we summarize the important roles of plant hormones, including auxin, brassinosteroids (BRs), Gibberellins (GAs), ethylene (ET), and jasmonates (JAs), in regulating plant growth under warm temperature conditions. This provides a picture on how plants sense and transduce the warm temperature signals to regulate downstream gene expression for controlling plant growth under warm temperature conditions via hormone biosynthesis and signaling pathways.

Opuntia ficus-indica the key plant in climate change: characteristics, cultivation and uses

The Opuntia genus, belonging to the Cactaceae family, has about 300 species, of which Opuntia ficus indica, or Prickly Pear, is considered the best known and most significant. Opuntia ficus indica have been used in Mexico and Latin America since pre-hispanic times as a food and medicinal resource. In recent years, prickly pear cultivation has increased mainly because this plant used for food, medicinal and livestock purposes is able to withstand extreme drought conditions in relatively poor soils. The fruits of the prickly pear are of various colours such as yellow, orange, purple and white, and when ripe their sweet pulp is characterised by a low acidity. It possesses numerous nutritional and therapeutic virtues such as richness in carbohydrates, vitamins, minerals and considerable antioxidant, anti-diabetes, anti-cancer fruit activity. Opuntia also has laxative properties due to its soluble fibres and mucilage. The infusion of the harvested and dried flowers has a depurative effect; it has a mild, gentle diuretic and relaxing action on the renal excretory system. Opuntias are also exploited as an alternative and cheap source of source of food for animals and as an ornamental plant. Opuntia ficus indica is grown in subtropical, tropical and warm-temperature areas; it is mainly cultivated in Tunisia, Libya and Egypt. The Prickly Pear finds a particularly favourable habitat in Sardinia, Calabria, Apulia and Sicily, where it is also cultivated, as well as in Spain and North Africa, for the exploitation of its edible fruit, with its delicately sweet pulp, rich in minerals, especially calcium and phosphorus, and vitamin C. In this review, the characteristics, cultivation methods, main uses of the plant and fruits, market and adversities of Opuntia ficus indica are described.

Antipredator behavior of newts (Cynops pyrrhogaster) against snakes

Newts and salamanders show remarkable diversity in antipredator behavior, developed to enhance their chemical defenses and/or aposematism. The present study reports on the antipredator behavior of newts (Cynops pyrrhogaster) in response to snakes. Newts displayed a significant amount of tail-wagging and tail-undulation in response to a contact stimulus from the snake’s tongue, which is a snake-specific predator stimulus, as compared to a control stimulus (behavioral scores: tongue, 1.05 ± 0.41; control, 0.15 ± 0.15). Newts that were kept in warm temperature conditions, 20°C (at which snakes are active in nature), performed tail displays more frequently than newts kept in low-temperature conditions, 4°C (at which snakes are inactive in nature). Our results suggest that the tail displays of C. pyrrhogaster could function as an antipredator defense; they direct a snake’s attention to its tail to prevent the snake from attacking more vulnerable body parts. We also discussed the reason for inter-populational variation in the tendency of newts to perform tail displays.

Interdecadal Changes in the Relationship between Wintertime Surface Air Temperature over the Indo-China Peninsula and ENSO

Interdecadal variations of the relationship between El Niño-Southern Oscillation (ENSO) and the Indo-China Peninsula (ICP) surface air temperature (SAT) in winter are investigated in the study. Generally, there exists a positive correlation between them during 1958–2015 because the ENSO-induced anomalous western North Pacific anticyclone (WNPAC) is conducive to pronounced temperature advection anomalies over the ICP. However, such correlation is unstable in time, having experienced a high-to-low transition around the mid-1970s and a recovery since the early-1990s. This oscillating relationship is owing to the anomalous WNPAC intensity in different decades. During the epoch of high correlation, the anomalous WNPAC and associated southwesterly winds over the ICP are stronger, which brings amounts of warm temperature advections and markedly heats the ICP. Differently, a weaker WNPAC anomaly and insignificant ICP SAT anomalies are the circumstances for the epoch of low correlation. It is also found that substantial southwesterly wind anomalies over the ICP related to the anomalous WNPAC occur only when large sea surface temperature (SST) anomalies over the northwest Indian Ocean (NWIO) coincide with ENSO (namely when the ENSO-NWIO SST connection is strong). The NWIO SST anomalies are capable of driving favorable atmospheric circulation that effectively alters ICP SAT and efficiently modulates the ENSO-ICP SAT correlation, which is further supported by numerical simulations utilizing the Community Atmospheric Model, version 4 (CAM4). This paper emphasizes the non-stationarity of the ENSO-ICP SAT relationship and also uncovers the underlying modulation factors, which has important implications for the seasonal prediction of the ICP temperature.

Cold-induced Arabidopsis FRIGIDA nuclear condensates for FLC repression

Plants use seasonal temperature cues to time the transition to reproduction. In Arabidopsis thaliana, winter cold epigenetically silences the floral repressor locus FLOWERING LOCUS C (FLC) through POLYCOMB REPRESSIVE COMPLEX 2 (PRC2)1. This vernalization process aligns flowering with spring. A prerequisite for silencing is transcriptional downregulation of FLC, but how this occurs in the fluctuating temperature regimes of autumn is unknown2–4. Transcriptional repression correlates with decreased local levels of histone H3 trimethylation at K36 (H3K36me3) and H3 trimethylation at K4 (H3K4me3)5,6, which are deposited during FRIGIDA (FRI)-dependent activation of FLC7–10. Here we show that cold rapidly promotes the formation of FRI nuclear condensates that do not colocalize with an active FLC locus. This correlates with reduced FRI occupancy at the FLC promoter and FLC repression. Warm temperature spikes reverse this process, buffering FLC shutdown to prevent premature flowering. The accumulation of condensates in the cold is affected by specific co-transcriptional regulators and cold induction of a specific isoform of the antisense RNA COOLAIR5,11. Our work describes the dynamic partitioning of a transcriptional activator conferring plasticity in response to natural temperature fluctuations, thus enabling plants to effectively monitor seasonal progression.

Responses to Temperatures of Different Drosophila Species

Temperature is a critical environmental variable that affects the distribution, survival, and reproduction of most animals. Although temperature receptors have been identified in different animals, how these receptors respond to temperatures is largely unknown. Here we use modified single-fly thermotactic assays to analyze movements and temperature preferences of nine Drosophila species. The ability/inclination to move varies among these species and at different temperatures. Importantly, different species prefer various ranges of temperatures. While wild-type D. melanogaster flies avoid the warm temperature in the warm avoidance assay and the cool temperature in the cool avoidance assay, D. bipectinata and D. yakuba avoid neither warm nor cool temperatures and D. biarmipes and D. mojavensis do not avoid the warm temperature in the warm avoidance assay. These results demonstrate that Drosophila species have different mobilities and temperature preferences, thereby benefiting the research on molecular mechanisms of temperature responsiveness.Summary statementThe ability to move and the preference for temperatures vary among fly species when flies are exposed to steep temperature gradients.

The longevity response to warm temperature is neurally controlled via regulation of collagen genes

ABSTRACTLower temperatures have been associated with longer lifespan, while higher temperatures with shorter lifespan. These inverse effects of temperature on longevity were traditionally explained by the “rate of living theory”, which posits that higher temperatures increase chemical reaction rates, thus speeding up the aging process. Recent studies have identified specific molecules and cells that mediate the longevity response to temperature, suggesting that the temperature effects on aging are not simply thermodynamic but regulated processes. However, the mechanisms underlying such regulation are not well understood. In the current study, we found that Caenorhabditis elegans lacking NPR-8, a neuronal GPCR related to the mammalian neuropeptide Y receptors, exhibited extended lifespan at warm temperature. Such lifespan extension can be suppressed by re-expression of NPR-8 in the amphid sensory neurons AWB and AWC or by inactivation of NPR-8-regulated collagen genes. These results suggest that the warm temperature effect on longevity is regulated by the nervous system through controlling collagen gene expression. Our study potentially provides mechanistic insights into understanding the relationship between temperature and longevity, which could prove useful in mitigating negative impacts of increasing temperature due to global warming.

Theoretical Analysis of Vuilleumier’s Hypothetical Engine and Cooler

Vuilleumier machines are a promising technology for heating. Respective performances of Vuilleumier’s engine and cooler are generally unclear. In Stirling machines, performances can be determined based on PV power flow and heat flow methods. In this work, respective performances based on two methods in current Vuilleumier models were investigated. It was found that PV power flow and heat flow methods in current Vuilleumier models were ineffective for analysis of respective performances due to there being no piston as a boundary between Vuilleumier’s engine and cooler. Then, a virtual piston was assumed, and a virtual piston based Vuilleumier model (VPBVM) was developed. The relative Carnot efficiencies of the obtained engine and cooler were 53~64% and 43~49%, respectively, at conditions of 550 °C hot temperature, 50~70 °C warm temperature, and −20~10 °C cold temperature. The results indicated that respective performances obtained in VPBVM were reasonable. Moreover, the engine’s compression ratios could be obtained in VPBVM and were 1.2~1.24. Thus, VPBVM could be effective for the analysis of the Vuilleumier machine’s engine and cooler.