Oman is a Middle Eastern country that has traditionally been monotonically reliant on its indigenous fossil fuel supplies. Besides, the nation has also been a surplus producer and net exporter of oil which further highlights the prolonged fossil fuel dependency of Oman. Consequently, despite flourishing economically, environmental quality in Oman has persistently aggravated. These opposing economic and environmental performances have necessitated Oman to identify the factors which can enable Oman to decarbonize its economy for tackling the environmental concerns faced by the nation. Against this backdrop, this study aims to examine the symmetric and asymmetric effects of foreign direct investments, economic growth, and capital investments on carbon dioxide emissions in Oman during 1980–2019. Using relevant econometric estimation methods for controlling structural break concerns in the data, the findings reveal evidence of asymmetric environmental impacts associated with shocks to the nation’s foreign direct investment inflow, economic growth, and capital investment figures. Specifically, it is witnessed that positive shocks to the levels of foreign direct investment inflows, economic growth, and capital investments boost carbon dioxide emissions both in the short and long run. On the other hand, negative shocks to the levels of foreign direct investment inflows and economic growth are witnessed to reduce the emissions. Besides, the findings also validate the environmental Kuznets curve and pollution haven hypotheses in the context of Oman. Hence, considering these key findings, it is recommended that Oman should ideally pursues green economic growth policies by restricting inflows of unclean foreign direct investments and green its financial sector in order to collectively minimize its carbon dioxide emission figures.

Retinoid X receptor (RXR) has been found to be a major target in various processes of endocrine disruption from the exposure to organotin compounds (OTCs), including imposex in gastropod mollusks. It was also reported in bivalves that OTCs caused intersex and skewed sex ratio. In order to evaluate the effect of these ligand-like OTCs, we constructed a reconstituted yeast system (CfRE system) based on GAL4 yeast two-hybrid principle using scallop Chlamys farreri retinoid X receptor (CfRXRa) and retinoid X response element (RXRE) to investigate the ligand-induced transactivation of CfRXRa. Responses of CfRXRa to 9-cis retinoic acid (9cRA) and tested four OTCs showed concentration-dependent response which is comparable with reported RXRa in vitro assay of human and gastropods. The detective limits of the CfRE system were found to be 100 nM for 9cRA and 10–1000 nM for the tested OTCs. While the tested non-Sn endocrine disrupting chemicals, including Benzo[a]pyrene, 2,4-Dichlorophenol, Nonylphenol, and Tetrabromobisphenol A, showed no effect on CfRXRa response. The present assay system may provide a valuable tool for screening assessments of unidentified environmental ligand chemicals on bivalve mollusks. It is also useful for comparison of sensitivity differences among species exposed to EDCs.

This paper uses a quantile fixed-effect panel data approach to investigate how environmental policy stringency affects CO₂ emissions in a set of 32 countries from 1990 to 2015, using OECD data. This approach allows us to identify the asymmetric impact of policy stringency on emissions, considering the emission level recorded in each analysed country. More precisely, we posit that the effectiveness of environmental regulations and policies is influenced by the air pollution level. Our results show that an increase in policy stringency has a negative impact on emissions and that environmental stringency has a more powerful impact in the countries with lower levels of carbon emissions. In addition, we show that policy stringency measures only became effective after the implementation of the Kyoto agreement, whereas the policy stringency effect is stronger for EU countries at high risk of missing the 20–20-20 target in terms of greenhouse gas emissions. Lastly, policy implications refer to the need to adapt policy stringency measures to emission levels to increase their effectiveness. At the same time, the setting up of emission targets determines policymakers to be more engaged in the fight against carbon emissions.

The sustenance of a clean, natural, and relatively less tampered environment is one of the most important apprehensions of contemporary households, firms, and governments in the globalized world. Both developing and developed countries rely heavily on foreign direct investments (FDI) and institutional arrangements for economic prosperity and have feedback repercussions about environmental quality. Thus, the current paper attempts to explore such a triplex integrated linkage among bilateral FDI, institutional quality, and environmental quality proxied by CO₂ emissions intensity on each other for 19 selected G20 countries during 2009–2017. The empirical estimation of this paper takes into account three equations that jointly address the endogeneity problem by employing both static (such as seemingly unrelated regression and three-stage least square) and dynamic simultaneous econometric techniques (such as the system generalized method of moments) with a panel dataset considering host and source countries with 342-panel pairs for the selected sample time. The empirical results confirm that bilateral FDI reduces CO₂ emission intensity and strengthens the institutional quality of G20. It also supports the idea that institutional quality has a favorable and considerable impact on bilateral FDI. This paper confirms a positive and considerable feedback between environmental and institutional quality. Further, this study establishes a triplex relationship between these three factors. This study argues that governments should use incentives like tax cuts and additional subsidies to promote greener FDI in G20 nations. This is because it facilitates the employment of more modern technology and clean energy-efficient technologies to minimize emissions and spur economic growth.

The use of soil conditioners as bovine biofertilizer associated with mineral fertilization affect the physical and physicochemical quality of passion fruit. For fruit growth, post-harvest quality is crucial for production chain development, as it is the characteristic most used by the fresh consumption market for this fruit. In this sense, an experiment was carried out to investigate the effects of doses of bovine biofertilizer in the soil with and without nitrogen fertilization in the cultivation of yellow passion fruit. A randomized block design was adopted, with three replications in a 5×2 factorial scheme, referring to five doses of liquid bovine biofertilizer (B) diluted in water (A): 0% − control (0B + 4A); 25% (1B + 3A); 50% (2B + 2A); 75% (3B + 1A); and 100% (4B + 0A) with and without nitrogen fertilization applied to the soil. Urea was the nitrogen source used in this study. A total of 10 g plant⁻¹ of N was applied monthly at 30 and 60 days after transplanting, and after that age, 20 g plant⁻¹ was applied until the end of harvest. During the final phase of production and ripening, twelve fruits were harvested from each treatment in physiological maturation for physical and physicochemical characterization. The following analyses were performed: longitudinal diameter, transversal diameter, number of seeds per fruit, peel firmness, pulp yield, fruit peel percentage, pulp pH, soluble solids content; titratable acidity and soluble solids content/titratable acidity ratio. Data underwent analysis of variance by the F test means for nitrogen were compared by Tukey’s test and means for bovine biofertilizer, by regression. Nitrogen enhances the positive effect of bovine biofertilizer on the postharvest quality of yellow passion fruit. The association of biofertilizer and nitrogen improves fruit quality in comparison to plants without these inputs, except for pulp yield and fruit peel percentage, which suffered isolated effects from the factors. High doses of biofertilizer, above 75 and 100%, reduce soluble solids content and increase titratable acidity. The bovine biofertilizer has promising effects, but it does not replace nitrogen fertilization on the postharvest quality of yellow passion fruit.

The effect of toxic metals on roots is mainly studied in laboratory single-species experiments. Data for multi-species plant communities obtained in natural conditions are needed to understand ecosystem functioning under pollution. However, information on the industrial emission effects on the below-ground biomass is fragmentary and contradictory. This study aims to analyze the fine and coarse root mass changes along strong pollution gradients. We hypothesize that long-term soil contamination from copper smelter emissions decreases root mass in forests. We assessed the root mass in the forest litter and upper mineral soil layer along two pollution gradients caused by emissions from two copper smelters: in the Middle Urals (coniferous forests) and the Southern Urals (deciduous forests). We divided roots into two diameter fractions (0.5–2.0 mm and 2.1–5.0 mm). Only the fine root mass in the mineral soil in deciduous forests, but not the total root mass, decreased 2.2-fold near the smelter compared to uncontaminated areas. However, this effect is much weaker than for above-ground biomass, and it does not manifest at all in coniferous forests. The percentage of roots localized in the forest litter was negligible (7–10% in the coniferous forests and 2–5% in the deciduous forests) and remained unchanged along the pollution gradients. The absence of a pronounced effect of metal contamination from copper smelter emissions on the fine and coarse root mass may be regarded as evidence of plant communities’ resistance to long-term pollution through a shift in species composition toward tolerant species with high below-ground phytomass, particularly grasses.

COVID-19 pandemic has passed to the front all the contradictions of the beekeeping sector: the valuable role of bee products as immune enhancers and antiviral agents and the impact that unsustainability of human activities has on bees’ health and survival. The COVID-19 emergency led several countries to adopt severe restriction measures to contrast the infection. The lowering of industrial and commercial activities, transports, and the general lockdown had immediate consequences on the air quality, significantly improving environmental conditions. This had a positive impact on honeybees’ life’s quality. On the other hand, the bee and beehive transportation limitations threaten to hit food production by affecting the pollinator service, and this is particularly true in large, food-exporting countries like the USA and China where due to the few numbers of local bees, beekeepers import them by other countries and convey by truck hives for thousands of kilometers to pollinate crops. Furthermore, honeybee products, focusing on their natural pharmacological properties, can play an essential role as a potential natural contrast to the virus by enhancing the immunity defenses of both humans and animals, and their demand by consumers is expected to increase. Several researchers in the last months focused their attention on bee products to evaluate their effect in the cure of COVID-19 patients to ameliorate the symptoms or to contrast the coronavirus directly. This review reports these preliminary results.

Converting food waste into animal feed is highly useful for tackling the problem of food waste, which is particularly severe in developed countries. This study quantified the inefficiencies in converting food waste into animal feed and identified the sources of inefficiencies through a data envelopment analysis (DEA) of the monthly input–output data of two food waste–based animal feed producers in Japan. Our empirical analysis revealed that the producers of animal feed obtained from food waste (especially those treating food waste from retail and service industries) demonstrated inefficiencies in production technology and scale; moreover, expanding the production scale and improving the quality of food waste could enhance production efficiency. Based on the empirical results, specific policy implications were provided for the widespread use of animal feed obtained from food waste in Japan and elsewhere, globally. Furthermore, it was suggested that the COVID-19 pandemic contributed to a severe reduction in the production efficiency of animal feed producers treating food waste obtained from retail and service industries.

There are many risk factors associated with the spread of the COVID-19 pandemic, including low wind speed, fossil fuel energy production, air pollution, and smoking. Several studies argue that smoking is not a risk factor for COVID-19 morbidity among males or any other sub-group. The study aims to analyze the following research questions: (1) can smoking prevalence explain COVID-19 indicators (cases, mortality, and recovery)? Are these relationships monotonically increasing or decreasing? In an attempt to test the counter-intuitive possibility of a non-linear relationship, the proposed empirical model relaxes the assumption of monotonic change by applying the quadratic design and testing which one of the two competing models (quadratic or linear) better fits the data. Findings suggest more complex relationships between corona indices and prevalence of smoking than previously thought. These patterns might be explained by several conditions such as the attenuation of hypercytokinemia for mild levels of smoking prevalence compared with non-smokers, elevated social distancing of smokers in countries with lower smoking prevalence, and unidentified factors that should be examined in future research.

Alkaline pretreatment (APT) is the promising disintegration pretreatment for the anaerobic digestion (AD) of sewage sludge (SS) to improve digestion efficiency and methane yields. In this study, the heavy metals (HMs) were observed to be leached from SS in the APT process, which could lower the HMs secondary pollution risk of the residual biosolids after AD in land application. The sequential chemical extraction (SCE) experiment was performed to determine the variation in HMs’ distribution prior to and after the APT. The alkaline extracts were characterized in order to elucidate the HMs’ release mechanism. The APT could cause significant release of Zn and Cu with a maximum release efficiency of 96.6% ± 4.6% and 62.7% ± 8.4% under the condition of 1.5 mol/L NaOH and 25 ℃, respectively. The release efficiency of Zn and Cu was reduced by 63.0% and 21.7%, respectively, due to the extra addition of 0.25 mol/L NaCl at a NaOH concentration of 1.25 mol/L in the APT process. The release of Zn and Cu may be attributed to a complex process including disruption of microbial cells in SS, solubilization of organic matters bounded with metals, and the chemical leaching reaction of minerals. This study demonstrates the possibility to remove the Zn and Cu from the SS in the APT process before the AD disposal.