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The impacts of globalization, financial development, government expenditures, and institutional quality on CO2 emissions in the presence of environmental Kuznets curve Полный текст
2020
Le, Hoang Phong | Ozturk, Ilhan
The main objective of this study is to examine the impacts of globalization, financial development, government expenditures, and institutional quality on CO₂ emissions, incorporating energy consumption, and GDP per capita in the Environmental Kuznets Curve (EKC) model for 47 Emerging Market and Developing Economies (EMDEs) between 1990 and 2014. Owing to the presence of cross-sectional dependence and slope heterogeneity in the panel data, CADF and CIPS unit root tests are employed to validate the stationarity of the variables. Westerlund (Oxf Bull Econ Stat 69:709–748, 2007) and Banerjee and Carrion-i-Silvestre (J Time Ser Anal 38:610–636, 2017) cointegration tests denote the occurrence of cointegration among the variables. We employed CCEMG, AMG, and DCCE estimators to estimate heterogeneous parameters. The findings demonstrate that globalization, financial development, and energy consumption increase CO₂ emissions. Besides, the EKC hypothesis is affirmed in EMDEs. The accrual of governments’ financial and governance activities also boosts carbon dioxide emissions. Moreover, the analysis of Dumitrescu and Hurlin causality provides evidences for the feedbacks among the variables and CO₂ emissions. From the aforementioned results, there exists the trade-off effect between economic growth and environmental quality in EMDE countries. Finally, the empirical findings of this study indicate profound implications for policy makers, which recommend governments to consider the role of finance and governance in order to ensure that energy consumption, financial development, and sustainable economic growth are in harmony with the environment in the globalization era.
Показать больше [+] Меньше [-]Research on the characterization, reactivity, and transportability of porous silicon-coated nanoscale zero-valent iron Полный текст
2020
Xu, Ruiyang | Li, Juan | Tang, Jun | Wang, Yang | Niu, Yuan | Lu, Haojie
In practical conditions, the remediation efficiency is always very limited due to the rapid aggregation and deactivation of nanoscale zero-valent iron (nZVI). Porous SiO₂-coated technology can effectively suppress the agglomeration and oxidation of nZVI particle, resulting in the excellent dispersion and stability in water. A series of characterization results show that the porous SiO₂-coated Fe⁰ (Fe⁰@p-SiO₂) was a core-shell structure composite, with Fe⁰ as the core and the porous SiO₂ as the shell. Moreover, the prepared composite material has a large specific surface area (244.04 m²/g). The experiments of nitrobenzene (NB) reduction and one-dimensional simulation column indicated that the different amounts of NaOH in the preparation process lead to the different structures, shapes, and particle sizes of prepared composite materials, which have significant effects on its activity and transportability. Under the conditions investigated, the optimum ratio of Fe⁰@p-SiO₂ synthesis was nFₑ³⁺:n₍Tₑₜᵣₐₑₜₕₒₓy ₛᵢₗₐₙₑ, TEOS₎:nNₐOH = 1:1.85:1.19, and the corresponding reduction efficiency of NB to aniline (AN) and maximum normalized outflow concentration (Cₘₐₓ/C₀) was 100% and 0.79, respectively. The SiO₂-coated technology gives nZVI preparation greater control over the structure, shape, and particle size of modified nZVI composite, which has great potential in in situ remediation of groundwater contamination.
Показать больше [+] Меньше [-]The influence of flow rates and water depth gradients on the growth process of submerged macrophytes and the biomass composition of the phytoplankton assemblage in eutrophic water: an analysis based on submerged macrophytes photosynthesis parameters Полный текст
2020
Xu, Duo | Xia, Yan | Li, Zhaoxin | Gu, Yonggang | Lou, Chunhua | Wang, Hao | Han, Jinlong
Submerged macrophytes and phytoplankton assemblage play significant roles in the functioning of aquatic ecosystems. An experiment was carried out in Beijing in order to further evaluate the environmental factors that affect the growth of submerged macrophytes and phytoplankton assemblage. Submerged macrophytes (i.e., Vallisneria natans, Hydrilla verticillata, and Ceratophyllum demersum) constructed the growth system with some controllable influencing factors (i.e., the flow rate and water depth gradient). The flow rates were set separately as 4 L/h (1#), 6 L/h (2#), and 12 L/h (3#), while the water depth gradient was of 0.5–1.7 m in eutrophic water. Generally, all macrophytes could grow normally in the experiment, and the system could maintain and improve the effluent quality. The average removal rates of NH₃-N, COD, NO₃-N, TN, and TP were about 90%, 33%, 65%, 45%, and 40%, respectively. Seen from the results of the water depth gradient experiments, it is indicated that Vallisneria natans grows better in shallow water (0.5 m) and moderate shallow water (0.7 m) area, with an average relative growth rate (ARGA) of 57%. Hydrilla verticillata and Ceratophyllum demersum grow better in moderate deep water (1.2 m) and deep water (1.7 m) area (ARGA of 66% and 64%, respectively). Results of the flow rate experiments showed that the moderate flow rate (6 L/h) was the best for those three macrophytes’ growth. As the fitting results of the rapid light curves (RLCs) showed that the utilization of light and the tolerance to strong light were different for these macrophytes, if they are ranked in the order of the utilization and the tolerance from strong to weak, they are Hydrilla verticillata, Ceratophyllum demersum, and Vallisneria natans. Microbial analyses indicated that the overall system diversity of the experimental groups have been improved after cultivation of macrophytes. However, the accumulated Cyanobacteria caused by the low flow rate (1#) would lead to the suppression of microbial organics decomposition and nutrient metabolism in the macrophytes. To sum up, the results of this study provided theoretical guidance and technical support for the restoration of submerged macrophytes in eutrophic water.
Показать больше [+] Меньше [-]Antagonistic effects of nano-selenium on broilers hepatic injury induced by Cr(VI) poisoning in AMPK pathway Полный текст
2020
Zhang, Tian-guang | Zhao, Ya-li | Li, Lei | Zhou, Dong-hai
Cr (chromium, with common valence states of III and VI) is one of the common broiler feed additives. Liver injury and metabolic disorders could be caused by Cr₍VI₎ (hexavalent chromium) poisoning in broilers. Oxidative damage and metabolic disorders of organisms caused by heavy metals could be antagonized by nano-Se (nano-selenium). Nano-Se was chosen to study the antagonism of Cr₍VI₎ poisoning in broilers. AMPK (Adenosine 5,-monophosphate-activated protein kinase) is known as a “cell energy regulator” and plays a key regulatory role in carbohydrate and lipid metabolism. AMPK pathway and ACACA/CPT1A two genes were selected to study the prevention and treatment of nano-Se on Cr₍VI₎ poisoning in broilers and its molecular mechanism. For this purpose, 180 1-day-old AA (Arbor Acres) broilers were selected and randomly divided into 6 groups (n = 30) for further testing. After feeding as planned for 35 days, the livers of such broilers were taken for further examination including histopathological examination, differential gene expression analysis, and further validation on both mRNA and protein levels using related techniques like RT-qPCR, western blot, and immunohistochemistry (IHC). The histopathological examination suggested that the liver cells of the Cr₍VI₎ poisoning group were more severely injured than the nano-Se addition group. RT-qPCR results showed that the relative expression of ACACA gene in the Cr₍VI₎ poisoning group was significantly increased (P < 0.05), while the CPT1A gene’s expression was significantly decreased (P < 0.01). Those results were reversed in the nano-Se addition group. Western blot results were consistent with RT-qPCR and both suggested antagonism of nano-Se on Cr₍VI₎. Through morphological and histopathological observation, as well as the measurement of the mRNA and protein expression levels of ACACA and CPT1A genes in AMPK pathway, it was confirmed that nano-Se has certain preventive and protective effects on Cr₍VI₎ poisoning in broiler chickens. Furthermore, the adverse effects of Cr₍VI₎ on carbohydrate and lipid metabolism in broilers can be antagonized by nano-Se through AMPK pathway. A new method and experimental basis were provided to the future study of Cr₍VI₎ poisoning in broilers.
Показать больше [+] Меньше [-]Linear toxicokinetic of chlordecone in ewe’s serum Полный текст
2020
Saint-Hilaire, Maïlie | Rychen, Guido | Thomé, Jean-Pierre | Joaquim-Justo, Célia | Le Roux, Yves | Feidt, Cyril | Fournier, Agnès
Linear toxicokinetic of chlordecone in ewe’s serum Полный текст
2020
Saint-Hilaire, Maïlie | Rychen, Guido | Thomé, Jean-Pierre | Joaquim-Justo, Célia | Le Roux, Yves | Feidt, Cyril | Fournier, Agnès
Chlordecone (CLD) is an organochlorine pesticide used in banana fields of the French West Indies between 1972 and 1993. This use resulted in a long-term pollution of soils and the possible contamination of farm animals. Indeed, after involuntary ingestion of soil, CLD is absorbed and consequently leads to contaminated animals. The aim of this study was the determination of CLD half-life and the establishment of the linearity of CLD disappearance kinetics in non-lactating adult’s ewes. Chlordecone diluted in cremophor was intravenously administrated to ewes at different doses: 0.04, 0.2, or 1 mg kg⁻¹ body weight (n = 5 for each dose). Blood samples were collected from time t = 0 to time t = 84 days. Serum samples were extracted with a solid-phase extraction and analyzed by electron capture detection gas chromatography. A two-compartmental model was applied to the serum CLD kinetics. An additional statistical analysis was applied to the observed elimination parameters in serum according to the administrated dose, and no significant differences were detected. The linear elimination of CLD between 0.04 and 1 mg kg⁻¹ body weight allowed the possibility of ewe’s extrapolation half-life in this dose range. The estimated mean CLD half-life in ewes was 24 days. Overall, the results of this study will be useful to establish decontamination strategies in small ruminants reared in contaminated CLD areas. Graphical abstract Experimental design of the CLD toxicokinetic study in ewes
Показать больше [+] Меньше [-]Linear toxicokinetic of chlordecone in ewe’s serum Полный текст
2020
Saint-Hilaire, Maïlie | Rychen, Guido | Thomé, Jean-Pierre | Joaquim-Justo, Célia | Le Roux, Yves | Feidt, Cyril | Fournier, Agnès | Unité de Recherches Animal et Fonctionnalités des Produits Animaux (URAFPA) ; Université de Lorraine (UL)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) | LEAE-CART ; Université de Liège = University of Liège = Universiteit van Luik = Universität Lüttich (ULiège) | ANR-16-CE21-0008,INSSICCA,Stratégies innovantes pour sécuriser les systèmes d'élevage dans les zones contaminées par la chlordécone. Une approche modèle développée dans les Antilles et applicable dans les zones contaminées à l'échelle mondiale(2016)
International audience | Chlordecone (CLD) is an organochlorine pesticide used in banana fields of the French West Indies between 1972 and 1993. This use resulted in a long-term pollution of soils and the possible contamination of farm animals. Indeed, after involuntary ingestion of soil, CLD is absorbed and consequently leads to contaminated animals. The aim of this study was the determination of CLD half-life and the establishment of the linearity of CLD disappearance kinetics in non-lactating adult's ewes. Chlordecone diluted in cremophor was intravenously administrated to ewes at different doses: 0.04, 0.2, or 1 mg kg(-1) body weight (n = 5 for each dose). Blood samples were collected from time t = 0 to time t = 84 days. Serum samples were extracted with a solid-phase extraction and analyzed by electron capture detection gas chromatography. A two-compartmental model was applied to the serum CLD kinetics. An additional statistical analysis was applied to the observed elimination parameters in serum according to the administrated dose, and no significant differences were detected. The linear elimination of CLD between 0.04 and 1 mg kg(-1) body weight allowed the possibility of ewe's extrapolation half-life in this dose range. The estimated mean CLD half-life in ewes was 24 days. Overall, the results of this study will be useful to establish decontamination strategies in small ruminants reared in contaminated CLD areas.
Показать больше [+] Меньше [-]The power of habit: does production experience lead to pesticide overuse? Полный текст
2020
Huang, Yanzhong | Luo, Xiaofeng | Tang, Lin | Yu, Weizhen
The influence of farmers’ production experience on pesticide overuse is empirically analyzed by an endogenous switching probit model of pesticide use time, type, and dosage, based on survey data of 836 rice farmers in the Yangtze River Basin of China. We find that farmers’ production experience is an important cause of pesticide overuse, especially for small-scale farmers. Older, self-sufficient, small-scale, non-cooperative members and rice farmers with distant market towns are more likely to use pesticides based on their personal experience. In terms of pesticide use time, type, and dosage, 35.26%, 30.10%, and 28.52% of the samples, respectively, relied on a decision based on “experience.” Among them, farmers’ decision-making based on production experience for pesticide type and dosage are the key causes of pesticide overuse. These results will be helpful for reducing pesticides and correcting farmers’ “bad habits” within agricultural ecosystems.
Показать больше [+] Меньше [-]Application of Systems Thinking to the assessment of an institutional development project of river restoration at a campus university in Southern Brazil Полный текст
2020
Tasca, Fabiane Andressa | Goerl, Roberto Fabris | Michel, Gean Paulo | Leite, Nei Kavaguichi | Sérgio, Djesser Zechner | Belizário, Saman | Caprario, Jakcemara | Finotti, Alexandra Rodrigues
Rapid urban growth and high population density have become a problem for urban water resources, especially in developing countries. In general, the pollution of rivers and degradation of ecosystems are the result of both management failures and lack of sewage treatment. River restoration appears as a solution to improve this scenario, but it is common for there to be an absence of a systemic vision in these projects. Thus, this work analysed one of these projects as an initial approach to create coherent (qualitative) shared perspectives on the same problem. This project was developed in a Brazilian university territory in response to a Public Civil Action. Rivers within the university surroundings are degraded due to sewage disposal and wastewater pollution from external and internal sources within the university, but the programme actions contemplate only interventions within the perimeter of the university while excluding the other parts of its watershed. We analyse this problem under a Systems Thinking approach by using causal loop diagrams, being clear that ecosystems cannot be reduced to territorial limits only. The systemic map shows many actions that contribute to the water quality degradation, with emphasis on illegal dumping of wastewater (sewage) and land use change in the upstream areas prior to the university. Point measures are palliative and do not guarantee the quality of river water. Regulation of impervious surfaces and correct disposal of wastewater can improve the current panorama, but greater integration between stakeholders and other key actors is required.
Показать больше [+] Меньше [-]Modelling air quality levels of regulated metals: limitations and challenges Полный текст
2020
Ferreira, Joana | Lopes, Diogo | Rafael, Sandra | Relvas, Hélder | Almeida, Susana Marta | Miranda, Ana Isabel
Toxic metals as arsenic (As), cadmium (Cd), nickel (Ni), and lead (Pb) exist in the atmosphere as particulate matter components. Their concentration levels in the European Union (EU) are regulated by European legislation, which sets target and limit values as annual means, and by the World Health Organization (WHO) that defines guidelines and reference values for those metal elements. Modelling tools are recommended to support air quality assessment regarding the toxic metals; however, few studies have been performed and those assessments rely on discrete measurements or field campaigns. This study aims to evaluate the capability of air quality modelling tools to verify the legislation compliance concerning the atmospheric levels of toxic elements and to identify the main challenges and limitations of using a modelling assessment approach for regulatory purposes, as a complement to monitoring. The CAMx air quality model was adapted and applied over Porto and Lisbon urban regions in Portugal at 5 × 5-km² and 1 × 1-km² horizontal resolution for the year 2015, and the results were analysed and compared with the few measurements available in three locations. The comparison between modelled and measured data revealed an overestimation of the model, although annual averages are much lower than the regulated standards. The comparison of the 5-km and 1-km resolutions’ results indicates that a higher resolution does not necessarily imply a better performance, pointing out uncertainties in emissions and the need to better describe the magnitude and spatial allocation of toxic metal emissions. This work highlighted that an increase of the spatial and temporal coverage of monitoring sites would allow to improve the model design, contribute to a better knowledge on toxic metals atmospheric emission sources and to increase the capacity of models to simulate atmospheric particulate species of health concern.
Показать больше [+] Меньше [-]Characterization of earthworm α-amylases for dietary supplement development and biomass utilization Полный текст
2020
Akazawa, Shin-ichi | Ikarashi, Yuki | Yokoyama, Keisuke | Shida, Yosuke | Ogasawara, Wataru
Earthworms are useful soil-decomposing animals that possess various saccharification enzymes such as cellulases and amylases. Earthworms have also been traditionally used as antipyretic agents and medicines for preventing thrombotic diseases such as brain infarction. We previously developed a novel earthworm dietary supplement with fibrinolytic, cellulase, and amylase activities using high-pressure technology. However, the optimal temperature and pH required for amylase activity in bioindustry have not yet been investigated. In the present study, we purified and characterized two α-amylases of Eisenia fetida Waki, EfAMY1 and EfAMY2, which were monomeric enzymes of 63.8 kDa and 64.0 kDa, with specific activities of 69.2 and 40.4 units/mg, respectively. The optimal pH was 5.5 for both enzymes, and the optimal temperatures were 45 °C and 35 °C for EfAMY1 and EfAMY2, respectively; however, the enzymes were stable over a wide pH range (5–10) and at high temperature (up to 40 °C). These amylases showed higher specific activity and cold tolerance than those previously reported. These data should help to promote the development of E. fetida AMYs as functional dietary supplements and in biomass utilization.
Показать больше [+] Меньше [-]Characterization of bimetallic Fe/Ni nanoparticles supported by amphiphilic block copolymer and its application in removal of 1,1,1-trichloroethane in water Полный текст
2020
Huang, Kai | Bian, Hao | Zhang, Meng | Zhan, Cong | Li, Can | Zhang, Wei | Cui, Changzheng | Lu, Qiang | Lin, Kuangfei | Zhao, Jianhua
The iron and nickel bimetallic nanoparticles supported by the block copolymer polystyrene-block-poly (acrylic acid) (PS-b-PAA-nZVI-Ni) were synthesized successfully and were applied to assess the degradation of 1,1,1-trichloroethane (1,1,1-TCA) in water. An optimal dose of Ni loading was 2 wt%, while an optimal mass ratio of PS-b-PAA to Ni/Fe, i.e., 0.5:1, at which the dechlorination efficiency was a maximum. The size of PS-b-PAA-nZVI-Ni nanoparticles (average size ~ 50 nm) was three times smaller than that of nZVI-Ni due to the prevention of agglomeration of the resultant zerovalent iron nanoparticles by PS-b-PAA. In the applying aspect, the pseudo-first-order rate constant (Kₒbₛ) of 1,1,1-TCA removal by PS-b-PAA-nZVI-Ni was 0.0142 min⁻¹ within 240 min, which was approximately five times higher than nZVI. Meanwhile, PS-b-PAA-supported nZVI-Ni nanoparticles penetrated much deeper in quartz sand columns than nZVI-Ni nanoparticles, indicating PS-b-PAA had significant influence on nZVI transport. The findings from this study suggested that PS-b-PAA-nZVI-Ni, with its high reactivity, selective screening for 1,1,1-TCA, could be one significant potential for use as remedial agent to treat chlorinated solvents in water.
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