The inflationary dynamics and preheating in a model with a nonminimally coupled inflaton field in the metric and Palatini formalisms are studied in this paper. We find that in both formalisms, ...irrespective of the initial conditions, our Universe will evolve into a slow-roll inflationary era and then the scalar field rolls into an oscillating phase. The value of the scalar field at the end of the inflation in the Palatini formalism is always larger than that in the metric one, which becomes more and more obvious with the increase of the absolute value of the coupling parameter |ξ|. During the preheating, we find that the inflaton quanta are produced explosively due to the parameter resonance and the growth of inflaton quanta will be terminated by the backreaction. With the increase of |ξ|, the resonance bands gradually close to the zero momentum (k=0), and the structure of resonance changes and becomes broader and broader in the metric formalism, while it remains to be narrow in the Palatini formalism. The energy transfer from the inflaton field to the fluctuation becomes more and more efficient with the increase of |ξ|, and in the metric formalism the growth of the efficiency of energy transfer is much faster than that in the Palatini formalism. Therefore, the inflation and preheating show different characteristics in different formalisms.
There are data integration and estimation endogeneity problems while estimate the subjective welfare loss of air pollution, which may result in incompatible findings. This paper attempts to integrate ...the air pollution data and subjective well-being data on individual-level, and use the number of environmental laws and regulations in prefecture-level cities as an instrumental variable for air pollution to evaluate the welfare loss of air pollution. The results show that there is a causal effect between air pollution and individual subjective well-being. 1 μg/m3 increase of annual PM2.5 concentration in a city will result in a subjective welfare loss equivalent to 7.7% percent of household disposable income, which implies that previous studies may have underestimated the effect. Further mechanism analysis shows that the effect of PM2.5 on subjective well-being is more through physical health than through mental health.
Much attention is currently paid to microplastic (MP) pollution, particularly in marine systems. There is increasing concern regarding the potential toxicity of MPs to organisms at the physiological ...and morphological levels. However, little is known about the impact of MPs on aquatic life, despite their ubiquitous presence in freshwater ecosystems. In this study, the aquatic plant Utricularia vulgaris was exposed to 1, 2 and 5 μm polystyrene fluorescent MP particles at concentrations of 15, 70 and 140 mg/L for 7 days. The toxic effects of MPs on the growth rate and morphological and physiological characteristics of U. vulgaris were assessed. The results showed that the relative growth rates and the functional traits of leaves (morphological and photosynthetic) were significantly inhibited at a high concentration of MP particles (140 mg/L) when compared to the control group. The impacts on growth performance were likely due to bioaccumulation of MPs in the bladders, as shown by confocal microscopy. Furthermore, the antioxidative enzyme activities showed that high concentrations of MPs induce high ecotoxicity and oxidative damage to U. vulgaris. Thus, U. vulgaris has the potential to be an excellent bioindicator of MP pollution in freshwater ecosystems and should further be applied in ecological risk assessments of the effects of MPs on higher aquatic plants.
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•We explored effects of microplastics for submerged carnivorous aquatic plants.•Polystyrene microplastics have been ingested by the bladders.•Growth performance of U.vulgaris was reduced with increasing microplastic concentration.•U. vulgaris can be potential eco-friendly purifiers for microplastics biodegradation.
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We study, in the framework of open quantum systems, the entanglement dynamics for a quantum system composed of two uniformly accelerated Unruh-Dewitt detectors interacting with a bath of ...massive scalar fields in the Minkowski vacuum. We find that the entanglement evolution for the quantum system coupled with massive fields is always slower compared with that of the one coupled with massless fields, and this time-delay effect brought about by the field being massive can however be counteracted by a large enough acceleration, in contrast to the case of a static quantum system in a thermal bath, where this time delay is not affected by the temperature. Remarkably, the maximal concurrence of the quantum system generated during evolution may increase with acceleration for any inter-detector separation while that for static ones in a thermal bath decreases monotonically with temperature, and this can be considered as an anti-Unruh effect in terms of the entanglement generated.
The f(T) theory, which is an extension of teleparallel, or torsion scalar T, gravity, is recently proposed to explain the present cosmic accelerating expansion with no need of dark energy. In this ...Letter, we first perform the statefinder analysis and Om(z) diagnostic to two concrete f(T) models, i.e., f(T)=α(−T)n and f(T)=−αT(1−epT0/T), and find that a crossing of phantom divide line is impossible for both models. This is contrary to an existing result where a crossing is claimed for the second model. We, then, study the constraints on them from the latest Union 2 Type Ia Supernova (Sne Ia) set, the baryonic acoustic oscillation (BAO), and the cosmic microwave background (CMB) radiation. Our results show that at the 95% confidence level Ωm0=0.272−0.032+0.036, n=0.04−0.33+0.22 for Model 1 and Ωm0=0.272−0.034+0.036, p=−0.02−0.20+0.31 for Model 2. A comparison of these two models with the ΛCDM by the χMin2/dof (dof: degree of freedom) criterion indicates that ΛCDM is still favored by observations. We also study the evolution of the equation of state for the effective dark energy in the theory and find that Sne Ia favors a phantom-like dark energy, while Sne Ia+BAO+CMB prefers a quintessence-like one.
Access to the elusive deep‐ultraviolet by direct second harmonic generation (SHG) enabled by a new beryllium‐free zincoborate‐phosphate crystal is reported. Ba3(ZnB5O10)PO4, exhibits large SHG ...responses at 1064 and 532 nm and a short 180 nm absorption edge. Centimeter‐size crystals are grown, and quantum mechanical calculations demonstrate the key role played by ZnO4 tetrahedra in the enhanced optical responses.
Environmental regulation may lead to firm's behavior changes. This article explores the effects of environmental regulation on corporate tax avoidance activities. Using China's new Environmental ...Protection Law as a quasi-natural experiment, we construct a difference-in-difference-in-differences(DDD) strategy for estimation. We find that environmental regulation will significantly increase the corporate tax avoidance activities in polluting industries in highly regulated cities. We further examine the heterogeneous effects of political connection, and find that political connection may promote corporate tax avoidance activities under stringent environmental regulation. The promoting effects are mainly due to the political connection with local governments rather than with central government.
•We explore the effects of environmental regulation on corporate tax avoidance activities for the first time.•Environmental regulation will increase the corporate tax avoidance activities in polluting industries in highly regulated cities.•Political connection may promote corporate tax avoidance activities under stringent environmental regulation.
We investigate the properties of holographic heat engines with an uncharged accelerating non-rotating AdS black hole as the working substance in a benchmarking scheme. We find that the efficiencies ...of the black hole heat engines can be influenced by both the size of the benchmark circular cycle and the cosmic string tension as a thermodynamic variable. In general, the efficiency can be increased by enlarging the cycle, but is still constrained by a universal bound
2
π
/
(
π
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4
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as expected. A cross-comparison of the efficiencies of the accelerating black hole heat engines and Schwarzschild-AdS black hole heat engines suggests that the acceleration also increases the efficiency although the amount of increase is not remarkable.
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•Bacopa showed that bet-hedging strategies may serve to prevent the direct and indirect effects of microplastics in the soil.•Morphological characteristics and chlorophyll b content ...were significantly decreased.•Microplastics activate plant antioxidant defence system.•Microplastics affect the physical and chemical properties, microbial community structure and function of soil systems.
The ecological stress of microplastic contamination to ecosystem functioning and biota raises concerns worldwide, but the impacts of microplastics on wetland ecosystems (e.g., plants, microbes, and soil) have not been fully elucidated. In this study, we used a controlled pot experiment to determine the effects of different types (PS, PVC, PP and PE) of microplastics on the growth performance of wetland plants, soil chemical properties, enzyme systems and microbial communities. Microplastics can change the germination strategies of seeds, and there was also a reduction in fresh weight and plant height in Bacopa sp. Chlorophyllb synthesiswas significantly reduced in mixed microplastic treatments compared with controls. Microplastic addition in soil caused higher concentrations of reactive oxygen species in plants, which led to increased lipid peroxidation and activation of the antioxidant defence system. The organic matter, potassium, total nitrogen and phosphorus changed significantly in the presence of the four forms of microplastics, while soil pH was not substantially affected. Microplastics had a negative effect on soil enzyme activity, for example, PS MP particles significantly decreased sucrase activities in the soil after 40 days. The results of this study showed that microplastic addition decreased the richness and diversity of bacterial. When soil was exposed to polystyrene microplastics, the richness and diversity of algae significantly increased on the soil surface. Thus, microplastics can alters the structure of soil microbial communities, resulting in the enrichment of some special soil microbial taxa involved in nitrogen cycling. These results indicate both the direct and indirect effects of plastic residues on the plant-microbe-soil system, which has implications for potential further impacts on wetland ecosystem functioning.
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Using a reasonable choice in normalizing the timelike Killing vector, we investigate the thermodynamic properties of charged accelerating Anti-de Sitter (AdS) black holes. We find that the ...expression of the thermodynamic mass in the first law of thermodynamics displays an inextricably intertwining behavior with the charge due to the unusual asymptotic structure of the accelerating black holes. Meanwhile, the thermodynamic length as a potential conjugate to the varying cosmic string tension is introduced and analyzed in detail, and the possible phase behavior of the charged accelerating black holes is also discussed in a standard thermodynamic analysis. Furthermore, we also investigate the properties of holographic heat engines with charged accelerating AdS black holes as the working substance in a benchmarking scheme. We find that the efficiencies of the black hole heat engines can be influenced by both the size of the benchmark circular cycle and the cosmic string tension. More interestingly, the existence of charge may significantly increase the efficiencies of the black hole heat engines and make them be more sensitive to a varying cosmic string tension. A cross-comparison of the efficiencies of different black hole heat engines suggests that the acceleration also increases the efficiency and renders it more sensitive as the charge varies.
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