Asymmetric and time-frequency co-movements among innovation-themed investments and carbon emission efficiency: Thematic investing and hedging opportunities.

This study is aimed at investigating the asymmetric and time-frequency co-movements and the hedge or safe-haven properties of carbon efficient indices, the MSCI ACWI Sustainable Impact, and MSCI World EGS indices, in relation to technology and innovation-themed investments. In doing so, the ADCC-GJR-GARCH and wavelet coherence techniques are applied to a daily return series ranging from January 2019 to January 2023. Findings of the ADCC-GJR-GARCH model show negative and insignificant asymmetric linkage among underlying indices during the sample period. The S&P 500 carbon efficient index (CEI) acts as a strong hedge or safe-haven for technology and innovation-themed indices during tranquil and tumultuous periods. The MSCI ACWI Sustainable Impact, MSCI World EGS, and carbon efficient indices except for S&P 500 CEI exhibit weak hedge or safe-haven attributes. Wavelet coherence reveals negative (positive) co-movements between the thematic and carbon efficient indices in short-term (medium-term and long-term) horizons with consistent leading behavior of thematic indices to carbon efficient indices outcomes. It justifies the presence of short-lived hedging or safe-haven characteristics in the thematic domain for investors. These strong and weak hedge or safe-haven characteristics of low carbon and sustainability indices reveal that adding low carbon efficient and sustainable investments to a portfolio result in considerable diversification benefits for investors who tend to take minimal risk in both tranquil and tumultuous periods. The current findings imply that financial institutions, thematic investing companies, and governments need to encourage carbon efficient technology transfer and innovation-themed investments by increasing the fund allocations in underlying asset classes. Policy-making and regulatory bodies can encourage investors to make carbon-efficient and thematic investments and companies to issue carbon-efficient stocks or investments to safeguard social and economic risks during fragile periods. These investments can offer greater opportunities to combat the intensity of economic shocks on portfolios for responsible or sustainable investors.

Transcriptomic and biochemical insights into fall armyworm (Spodoptera frugiperda) responses on silicon-treated maize.

Background: The fall armyworm, Spodoptera frugiperda, is an agricultural pest of significant economic concern globally, known for its adaptability, pesticide resistance, and damage to key crops such as maize. Conventional chemical pesticides pose challenges, including the development of resistance and environmental pollution. The study aims to investigate an alternative solution: the application of soluble silicon (Si) sources to enhance plant resistance against the fall armyworm. Methods: Silicon dioxide (SiO2) and potassium silicate (K2SiO3) were applied to maize plants via foliar spray. Transcriptomic and biochemical analyses were performed to study the gene expression changes in the fall armyworm feeding on Si-treated maize. Results: Results indicated a significant impact on gene expression, with a large number of differentially expressed genes (DEGs) identified in both SiO2 and K2SiO3 treatments. Furthermore, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis identified critical DEGs involved in specific pathways, including amino acid, carbohydrate, lipid, energy, xenobiotics metabolisms, signal transduction, and posttranslational modification, significantly altered at both Si sources. Biochemical analyses further revealed that Si treatments inhibited several enzyme activities (glutamate dehydrogenase, trehalase, glucose-6-phosphate dehydrogenase, chitinase, juvenile hormone esterase, and cyclooxygenase while simultaneously inducing others (total protein, lipopolysaccharide, fatty acid synthase, ATPase, and cytochrome P450), thus suggesting a toxic effect on the fall armyworm. In conclusion, Si applications on maize influence the gene expression and biochemical activities of the fall armyworm, potentially offering a sustainable pest management strategy.

Effects of abiotic stresses on the expression of chitinase-like genes in Acyrthosiphon pisum.

Insect chitinases play a crucial part to digest chitin in the exoskeleton during the molting process. However, research on insect chitinase related to the environmental stress response is very limited. This study was the first conducted to expression analysis of chitinase- related genes in A. pisum under abiotic stresses. Here, we identified five chitinase-like proteins (ApIDGF, ApCht3, ApCht7, ApCht10 and ApENGase), and clustered them into five groups (group II, III, V, Ⅹ, and ENGase). Developmental expression analysis revealed that the five A. pisum chitinase-related genes were expressed at whole developmental stages with different relative expression patterns. When aphids were exposed to various abiotic stresses including temperature, insecticide and the stress 20-hydroxyecdysone (20E), all five chitinase genes were differentially expressed in A. pisum. The results showed that insecticide such as imidacloprid down-regulated the expression of these five Cht-related genes. Analysis of temperature stress of A. pisum chitinase suggested that ApCht7 expression was high at 10°C, which demonstrates its important role in pea aphids under low temperature. Conversely, ApCht10 was more active under high temperature stress, as it was significantly up-regulated at 30°C. Besides, 20E enhanced ApCht3 and ApCht10 expression in A. pisum, but reduced ApCht7 expression. These findings provide basic information and insights for the study of the role of these genes under abiotic stress, which advances our knowledge in the management of pea aphids under multiple stresses.

Antioxidant Enzymes and Heat-Shock Protein Genes of Green Peach Aphid (Myzus persicae) Under Short-Time Heat Stress.

The management of insect pests under fluctuating temperatures has become an interesting area of study due to their ability to stimulate defense mechanisms against heat stress. Therefore, understanding insect's physiological and molecular response to heat stress is of paramount importance for pest management. Aphids are ectothermic organisms capable of surviving in different climatic conditions. This study aimed to determine the effects of short-time heat stress on green peach aphid Myzus persicae under controlled conditions. In this study, short-time heat stress treatments at different temperatures 27, 30, 33, and 36°C with exposure times of 1, 3, 6, and 10 h, respectively, on the activities of antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and oxidants, such as malondialdehyde (MDA) and hydrogen peroxide (H2O2), were determined. The results showed that the short-time heat stress significantly increased the content of MDA of M. persicae by 71, 78, 81, and 86% at 36°C for the exposure times of 1, 3, 6, and 10 h, respectively, compared with control. The content of H2O2 increased by 75, 80, 85, and 88% at 36°C for the exposure times of 1, 3, 6, and 10 h, respectively, compared with the control. The SOD, POD, and CAT activities increased by 61, 76, and 77% for 1 h, 72, 83, and 84% for 3 h, 80, 85, and 86% for 6 h, and 87, 87.6, and 88% for 10 h at 36°C, respectively, compared with control. Again, under short-time heat stress, the transcription levels of Hsp22, Hsp23, Hsp27, SOD, POD, and CAT genes were upregulated compared with control. Our results suggest that M. persicae increased the enzymatic antioxidant activity and heat-shock gene expression as one of the defensive mechanisms in response to heat stresses.

Influence of Repetitive Square Voltage Duty Cycle on the Electrical Tree Characteristics of Epoxy Resin.

The application of wide band-gap power electronic devices brings more challenges to insulating packaging technology. Knowing the influence of applied voltage parameters on insulation performance is helpful to evaluate the insulation condition of electric power equipment. In this paper, the effect of repetitive square wave voltage duty cycle on the growth characteristics of electrical trees in epoxy resin was studied. The experimental results show that the square wave voltage duty cycle has a significant influence on treeing features. The electrical tree proportion initiation has shown a decreasing trend, and the shape of the electrical tree changes from pine-like to branch-like by increasing the duty cycles. The length and damaged area of electrical tree increased with the increase in the duty cycle up to 10% and then decrease by increasing the duty cycle higher than 30%. It indicates that a low duty cycle will enhance the electron injection and accumulate space charges and thus accelerate electrical tree development. Under short duty cycles, the electric field due to the shielding effect near the needle tip suppresses the electrical tree growth, which results in treeing growth stagnation. The obtained results are helpful to keep these parameters in mind during the design of epoxy-based insulation such high-voltage rotating machines and power electronic device packaging.