The impact of fiscal transfer payments on energy conservation and emission reduction in China: Does the development stage matter?

Fiscal transfer payments (TRANS) are the institutional supplement of Chinese-style fiscal decentralization, which is of great significance to economic development. However, the relationship between TRANS and energy conservation and emission reduction (ECER) remains to be further discussed. Using panel data of 30 provinces in China from 2003 to 2020, this study empirically examines the impact of TRANS on energy-environmental performance (EEP) from the perspectives of influence mechanism, regional heterogeneity and nonlinearity. The results show that the influence of TRANS on ECER presents an obvious U-shaped relationship, and this influence has regional heterogeneity. At the same time, the investment-driven effect, infrastructure effect and industrial structure effect are important channels through which TRANS affect ECER. The partially linear functional coefficient models show that TRANS have different effects in different development stages. With the continuous improvement of economic level and urbanization level, the promotion effect of TRANS on ECER is more and more obvious. These results indicate that the government should increase fiscal investment in ECER, and pay attention to the development stage of different regions.

Changes in ecological networks and eco-environmental effects on urban ecosystem in China's typical urban agglomerations

Exploring the changes in ecological networks (ENs), its eco-environment effects and the differences in urban agglomerations in various urbanization stages are important for achieving sustainable ecosystem management and a better layout of ecological network. In this study, China's three typical urbanization agglomerations, Beijing-Tianjin-Hebei urban agglomeration (BTH), Yangtze River Delta urban agglomeration (YRD), and Pearl River Delta urban agglomeration (PRD), were selected as the study area. Spatiotemporal changes in ENs, the changing patterns, its eco-environment effects, and impacts of rapid urbanization were analyzed by environment indices, buffer analysis, and correlation analysis. The results showed a great lost in ENs from 2000 to 2015. Four patterns were seen in changing ENs: decomposition process (DP), internal change process (ICP), polycondensation process (PP), and external change process (ECP). ICP was dominated in YRD and PRD. ECP was the main pattern in core areas of BTH. The correlation analysis with YRD as the example showed that the changes in ENs had a certain impact on the eco-environment, especially in the 10-km buffer zone. The decrease of ENs was related to the increase of developed land, and the closer to the core area, the higher the correlation coefficient was. Reduction of ENs would slow down to a certain extent, when the agglomeration is in a higher urbanization stage. Different directions of restoration and optimization of ENs were proposed for the three urban agglomerations. The study will provide support for sustainable management and restoration and optimization of ENs for China's agglomerations.

Testing the impact of first-mover advantage on household energy-related carbon emissions: an exploratory study from six urban agglomerations in China

The household sector has become the second-largest source of energy consumption and CO₂ emissions in China. It is important to understand the trends and changing mechanisms of household energy-related CO₂ emissions (HECEs) in different social stages for mitigating the impact of climate change. However, the existing trends in HECEs and whether they are congruent with the expectation that HECEs in later developed areas are lower than those in priority areas under the same economic level are unclear. Here, we compared the per capita HECEs (PHECEs) of urban agglomerations under the same economic standards and analyzed the causes of the comparative results. We find that (1) HECEs increased rapidly from 3.65 × 10⁸ t to 12.42 × 10⁸ t during 1995-2017, with an average annual growth rate of 14.19%; (2) urban agglomerations that developed earlier do not have higher PHECEs. The PHECEs of urban agglomerations with moderate and later development do not decrease under increased social, technological, and cognitive conditions; (3) carbon intensity (CI), energy intensity (EI), and per capita regional gross domestic product (PCG) have a positive impact on PHECEs, and the potential impact of EI on PHECEs reduction is greater; (4) the effects of CI, EI, and PCG on PHECEs in different urban agglomerations are various. However, these effects are similar within urban agglomerations. Our study provides a reference for reducing CO₂ emissions in the household sector and for the green development of urban agglomerations and emphasizes that the growth of HECE at a reasonable level is necessary when technology does not meet sufficient constraints.

GABA shunt contribution to flavonoid biosynthesis and metabolism in tea plants (Camellia sinensis)

γ-Aminobutyric acid (GABA), a signal molecule, is regarded as the intersection node of carbon and nitrogen metabolism, and its contributions to flavonoid metabolism in tea plant growth and development remain unclear. The correlation between the GABA shunt and flavonoid metabolism in tea plants is worth to explore. Secondary metabolites and their correlations with the taste of tea soup made from tea plants (Camellia sinensis) during different seasons were investigated. Related secondary metabolites and transcript profiles of genes encoding enzymes in the GABA shunt, flavonoid pathway and polyamine biosynthesis were measured throughout the tea plant growth seasons and after exogenous GABA applications. In addition, the abundance of differentially expressed proteins was quantified after treatments with or without exogenous GABA. The tea leaves showed the highest metabolite concentrations in spring season. CsGAD, CsGABAT, CsSPMS, CsODC, CsF3H and CsCHS were found to be important genes in the GABA and anthocyanin biosynthesis pathways. GABA and anthocyanin concentrations showed a positive correlation, to some extent, CsF3H and CsCHS played important roles in the GABA and anthocyanin biosynthesis.

Soil fertility, chemical properties, and pollutant removal efficiency of Salicornia europaea in response to different times and duration of wastewater irrigation

Halophytes are the good candidates in coastal saline areas which could be irrigated with wastewater. The purpose of this study was to evaluate the soil-water-plant system under control and wastewater irrigation (containing toxic elements and organic matter) at three durations (vegetative, flowering, and reproductive stages) and two exposure times (2 and 4 days in each stage). The results obtained in the experimental tests for wastewater irrigation indicated that the Salicornia is efficient for the removal of chemical oxygen demand (61%), biochemical oxygen demand (74%), total suspended solids (47.6%), and ammoniacal nitrogen (64%) at the reproductive stage. At the same time, the average nitrate concentration increased to 51.3 mg L^-1 with more solids. Regardless of wastewater irrigation duration, irrigation with wastewater significantly increased organic matter, nitrogen, phosphorus, and potassium of the soil. The Mg²⁺ and Ca²⁺ contents in the aboveground biomass of the plants were also high ranged from 0.58 to 1%, and 0.43 to 0.68 mg g^-1 DW, respectively. All the exchangeable cations other than Na⁺ were higher for wastewater irrigation at the flowering stage. Plants maintained noticeably higher Ca²⁺/Na⁺ and K⁺/Na⁺ ratios in the roots than those in the shoots except for 4 days after the reproductive stage. S. europaea is well adapted to grow in wastewater irrigation and can tolerate hypoxic conditions through improving water and soil quality.

Nitrogen accumulation in forest floors with introduced Pinus pinea and Pinus pinaster in dune site

Introduced stone pine (Pinus pinea L.) and maritime pine (Pinus pinaster Aiton) stands were sampled 60 years after plantation in Istanbul-Durusu (Terkos), Turkey. Sampling was conducted at four different developmental stages (mean diameter of trees at 1.3-m height (DBH) in stands: SDF = < 8 cm, MDF = 8-20 cm, LDF = 20-36 cm, and UDF > 36 cm), with 15 replicated sample plots for each species and developmental stage, for a total of 120 sample plots. The forest floor was sampled in 5 replications in each sample plot. The forest floor samples were divided into two layers: L + F (litter + fermentation) and H (humus), and the oven dry mass and nitrogen (N) content were determined. As a result, the masses of the total forest floor and of both layers were significantly different among the development stages with an increasing trend in maritime pine stands despite no significant difference found in the mass of the humus layer in stone pine stands. However, total forest floor accumulation significantly increased with the development stage (28-60 t/ha in stone pine and 17-64 t/ha in maritime pine). In both species, the N concentrations in the forest floor layers differed significantly among the development stages, and the N concentrations tended to increase as the development stage increased in the L + F layer, whereas a fluctuating trend was observed in the H layer. Although the N content of the humus layer of stone pine did not show a significant difference among the development stages, the N content in the total forest floor was determined to be 0.1-0.5 t/ha in maritime pine and 0.2-0.5 t/ha in stone pine. The relationship between the mean stand DBH and the N stock of the total forest floor was determined to have a higher correlation in maritime pine (R² = 0.8) than stone pine (R² = 0.4). In conclusion, the nitrogen concentrations and nitrogen contents of the forest floor were remarkably different in stands introduced with different tree species, indicating the accumulation of forest floor nitrogen.

Biomass estimation of aboveground tree components for Turkey oak (Quercus cerris L.) in south-eastern Turkey

Biomass equations were developed for different components of oak trees (Quercus cerris L.), which have been managed in coppices at different development stages-small-diameter forest (SDF) and medium-diameter forest (MDF). In this context, four biomass regression models-two based on diameter at breast height (DBH) alone and two based on DBH and total tree height (H)-were developed for each of the crown, stem, and total aboveground biomass components. Akaike's information criterion (AIC), root mean square error percentage (RMSE (%)), mean absolute error percentage (MAE (%)), adjusted coefficient of determination (Adj.R²), and bias values were used to evaluate and compare the suitability of a total of 12 regression models developed for biomass components. As a result, in the estimation of crown biomass, only DBH-based models provided higher estimation accuracy than DBH-H-based models. For the most suitable model, estimated values were Adj.R² = 0.60, bias = - 0.009, RMSE = 66%, and MAE = 41%. In models developed to estimate stem biomass, the estimation accuracy of DBH-H-based models was higher. In the goodness-of-fit statistics calculated for the most suitable model, Adj.R², bias, RMSE, and MAE were 0.89, 0.010, 38%, and 23%, respectively. The models developed to estimate the total aboveground biomass were all close in terms of estimation accuracy. The biomass components (crown and stem) in the total aboveground biomass were proportionally as follows: crown at 38% and stem at 62% in the SDF stage, and crown at 35% and stem at 65% in the MDF stage, indicating lower crown and higher stem partitioning as the development stage increased.

Physicochemical properties and bioactivities of Lentinula edodes polysaccharides at different development stages

Lentinula edodes polysaccharides from at four different development stages (referred to L1, L2, L3 and L4, respectively) were extracted by hot water method, and graded ethanol precipitation to final concentration of 20%, 50% and 70%, then12 crude polysaccharide fractions (referred to L1P20, L2P20, L3P20; L4P20, L1P50, L2P50, L3P50, L4P50 and L1P70, L2P70, L3P70, L4P70, respectively) were obtained. Physicochemical properties and exoteric bioactivities of the crude polysaccharide fractions were measured. The results of physicochemical properties revealed that extraction yields of P20 fractions were significantly higher than those of P50 and P70 fractions, and the contents of polysaccharide and β-glucan in L3P50 fractions were higher, and the viscosity-average molecular weight reached a maximum at L2, and high molecular weight polysaccharides could be obtained at a low alcohol concentration in P20 fractions, and the glycosidic bonds were found to exist in all crude polysaccharide fractions. These crude polysaccharide fractions showed different bioactivities, wherein the polysaccharides of higher molecular weight in P20 fractions had greater bioactivity. These results showed that immature stage of Lentinula edodes was the optimal harvest time for obtaining higher bioactivity of crude polysaccharides.

Interspecific associations of dominant tree populations in a virgin old-growth oak forest in the Qinling Mountains, China

BACKGROUND

Understanding interspecific associations in old-growth forests will help to reveal mechanisms of interspecific replacement in the process of forest development and provide a theoretical basis for vegetation restoration and reestablishment. In this study, we analyzed interspecific associations of eleven dominant tree populations of varying development stages in an old-growth oak forest stand in the Qinling Mountains, China. We examined overall interspecific associations (multiple species) and pairwise interspecific associations (two species).

RESULTS

Interspecific competition was intense during forest development and was the main factor driving succession. Community structure appears to become more stable over time which supports the harsh-benign hypothesis that interspecific competition is more common in stable sites.

CONCLUSION

Old growth oak (Quercus spp.) forests are distributed widely around the world in part due to oak being a typical K-selected species. K-selected species produce fewer, high-quality offspring with higher survival rates, strong competitive ability, and longevity. The resulting distribution shifted from clumped to random, likely as a result of intense interspecific competition creating ecological niche differentiation.

PBTK modelling platforms and parameter estimation tools to enable animal-free risk assessment: recommendations from a joint EPAA--EURL ECVAM ADME workshop

Information on toxicokinetics is critical for animal-free human risk assessment. Human external exposure must be translated into human tissue doses and compared with in vitro actual cell exposure associated to effects (in vitro-in vivo comparison). Data on absorption, distribution, metabolism and excretion in humans (ADME) could be generated using in vitro and QSAR tools. Physiologically-based toxicokinetic (PBTK) computer modelling could serve to integrate disparate in vitro and in silico findings. However, there are only few freely-available PBTK platforms currently available. And although some ADME parameters can be reasonably estimated in vitro or in silico, important gaps exist. Examples include unknown or limited applicability domains and lack of (high-throughput) tools to measure penetration of barriers, partitioning between blood and tissues and metabolic clearance. This paper is based on a joint EPAA--EURL ECVAM expert meeting. It provides a state-of-the-art overview of the availability of PBTK platforms as well as the in vitro and in silico methods to parameterise basic (Tier 1) PBTK models. Five high-priority issues are presented that provide the prerequisites for wider use of non-animal based PBTK modelling for animal-free chemical risk assessment.

Cell wall glycosidase activities and protein content variations during fruit development and ripening in three texture contrasted tomato cultivars

Excessive softening is the main factor limiting fruit shelf life and storage. It is generally acceptable now that softening of fruit which occurs during the ripening is due to synergistic actions of several enzymes on cell wall polysaccharides. As a subject for this study, we have assayed some glycosidase activities using three tomato species (Lycopersicon esculentum) contrasted for their texture phenotypes; the cherry tomato line Cervil (Solanum lycopersicum var. cerasiforme), a common taste tomato line Levovil (S. lycopersicum Mill.) and VilB a modern line, large, firmer and with good storage capability. Four glycosidase activities namely α-galactosidase, β-galactosidase, β-mannosidase and β-glucosidase were extracted from tomato's cell wall of the three species. Cell wall protein from fruits pericarp was extracted and compared among the three cultivars at the following stages; 14 days post anthesis (14DPA) fruit; 21 days post anthesis (21DPA), turning (breaker), red and over ripe. When glycolytic activities were also compared among these cultivars at the precited development stages, gross variations were noticed from stage to stage and also from species to species in accordance with the fruit firmness status. Interestingly, VilB cultivar, the firmer among the other two, though possessed the highest total protein content, exhibited the lowest enzymatic activities. Taken together, these results may therefore allow us to conclude that studies of glycolytic activities in a single tomato cultivar cannot be generalized to all species. On the other hand, relating fruit development to glycosidase activities should logically be coupled to these enzymes from cell wall compartment.