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Economic growth and energy consumption in Brazil: cointegration and causality analysis 全文
2019
Mele, Marco
Energy is a crucial part of any economy and holds a central position in enhancing social development in the world. Energy consumption and the economy in Brazil have both increased in the past decade. In this paper, time series statistics from 1980 to 2017 will be used to analyze the relationship between real GDP per capita and energy consumption to will examine how energy use in the country affects economic growth using causality models. This is established through testing for stationarity using Kwiatkowski–Phillips–Schmidt–Shin (KPSS) test for trend stationarity. A cointegration relationship is found between the two variables.
显示更多 [+] 显示较少 [-]Electrokinetic remediation of antibiotic-polluted soil with different concentrations of tetracyclines 全文
2019
Li, Binxu | Zhang, Zhiguo | Ma, Yanlin | Li, Yanling | Zhu, Changxiong | Li, Hongna
This study investigated the efficacy of electrokinetic remediation of soils polluted with different concentrations of tetracyclines (TCs). Three widely used TCs (oxytetracycline, chlortetracycline, and tetracycline) were selected, and concentrations of 0, 5, 10, 20, and 50 mg/kg (C0, C5, C10, C20, C50) were selected for comparison. Antibiotic-polluted soils with no electric field served as controls. The average removal rates of TCs in different treatments ranged from 25 to 48% after 7-day remediation. The contributing ratios of electrokinetics to TCs removal varied from 22 to 84%. The concentrations of NH₄⁺ increased in soils and electrolytes, which indicated the decomposition of TCs in the electric field. The highest removal amount of TCs was obtained in the C50 treatment, due to efficient reactions of TCs with oxidative radicals generated during the electrolysis. The fluctuant range of pH in the electrolytes was decreased with increasing concentration of TCs, while the soil pH was increased. The removal rate of antibiotic-resistant bacteria (ARB) in the C5 treatment was significantly higher than that in other treatments. The abundance of antibiotic resistance genes (ARGs) increased with the concentrations of TCs in soils. It might result from the induction of increasing selective pressure of antibiotics. Significant removal of ARGs occurred in the C50 treatment (38–60%). In terms of controlling ARB and ARGs, which were more resistant, the electrokinetic technology showed advantageous effects. Above all, electrokinetic technology provides an effective remediation method, especially for TC-polluted soil with a concentration of 20–50 mg/kg.
显示更多 [+] 显示较少 [-]Construction of precious metal-loaded BiOI semiconductor materials with improved photocatalytic activity for microcystin-LR degradation 全文
2019
Zhang, Fan | Peng, Hui | Jiang, Qishao | Wang, Chuqiao | Xu, Xia | Wang, Liping
The composite photocatalyst of precious metal loaded on BiOI (M/BiOI, M = Pt, Au, Ag) was prepared by photochemical deposition and used for the photocatalytic degradation of microcystins (MC-LR). The material was characterized by X-ray powder diffraction (XRD), field emission scanning electron microscopy (FESEM), ultraviolet visible (UV-vis) diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy (XPS), and photoluminescence spectra (PL). The effect of photodegradation of MC-LR and the possible mechanism were investigated. It turned out that, among precious metals of Pt, Au, and Ag, Ag had the most significant improvement for photocatalytic activity of BiOI and Au was the least. The Ag/BiOI catalyst was illuminated 2 h under the simulated visible-light condition with the optimal load ratio of Ag catalyst (1.0 wt%) and the 2-h illumination under simulated visible-light condition, the degradation rate of MC-LR was 61.26% ± 0.12%. In addition, through the experiment of trapping agent and the analysis of electron spin resonance (ESR), we could conclude that the main active species is O₂⁻ in the process of the degradation of MC-LR by three precious metal-loaded BiOI semiconductor materials.
显示更多 [+] 显示较少 [-]Developing air exchange rate models by evaluating vehicle in-cabin air pollutant exposures in a highway and tunnel setting: case study of Tehran, Iran 全文
2019
Nayeb Yazdi, Mohammad | Arhami, Mohammad | Delavarrafiee, Maryam | Ketabchy, Mehdi
The passengers inside vehicles could be exposed to high levels of air pollutants particularly while driving on highly polluted and congested traffic roadways. In order to study such exposure levels and its relation to the cabin ventilation condition, a monitoring campaign was conducted to measure the levels inside the three most common types of vehicles in Tehran, Iran (a highly air polluted megacity). In this regard, carbon monoxide (CO) and particulate matter (PM) were measured for various ventilation settings, window positions, and vehicle speeds while driving on the Resalat Highway and through the Resalat Tunnel. Results showed on average in-cabin exposure to particle number and PM₁₀ for the open windows condition was seven times greater when compared to closed windows and air conditioning on. When the vehicle was passing through the tunnel, in-cabin CO and particle number increased 100 and 30%, respectively, compared to driving on highway. Air exchange rate (AER) is a significant factor when evaluating in-cabin air pollutants level. AER was measured and simulated by a model developed through a Monte Carlo analysis of uncertainty and considering two main affecting variables, vehicle speed and fan speed. The lowest AER was 7 h⁻¹ for the closed window and AC on conditions, whereas the highest AER was measured 70 h⁻¹ for an open window condition and speed of 90 km h⁻¹. The results of our study can assist policy makers in controlling in-cabin pollutant exposure and in planning effective strategies for the protection of public health.
显示更多 [+] 显示较少 [-]A biophysical probe on the binding of 2-mercaptothioazoline to bovine hemoglobin 全文
2019
Zou, Luyi | Zhang, Xiaoyue | Shao, Mingying | Sun, Ruirui | Zhu, Yuting | Zou, Binbin | Huang, Zhenxing | Liu, He | Teng, Yue
2-Mercaptothiazoline (MTZ) is broadly present in daily use as an antifungal reagent, a brightening agent, and a corrosion inhibitor. MTZ is potentially harmful for human health. Although the toxic effects of MTZ on experimental animals have been reported, the effects of MTZ on the proteins in the circulatory system at the molecular level have not been identified previously. Here, we explored the interaction of MTZ with bovine hemoglobin (BHb) in vitro using multiple spectroscopic techniques and molecular docking. In this study, the binding capacity, acting force, binding sites, molecular docking simulation, and conformational changes were investigated. MTZ quenched the intrinsic emission of BHb via the static quenching process and could spontaneously bind with BHb mainly through van der Waals forces and hydrogen bond. The computational docking visualized that MTZ bound to the β2 subunit of BHb, which further led to some changes of the skeleton and secondary structure of BHb. This research provides valuable information about the molecular mechanisms on BHb induced by MTZ and is beneficial for clarifying the toxicological actions of MTZ in blood.
显示更多 [+] 显示较少 [-]An assessment of vegetation management practices and burrow fumigation with aluminum phosphide as tools for managing voles within perennial crop fields in California, USA 全文
2019
Baldwin, Roger A. | Stetson, Denise I. | Lopez, Manuel G. | Engeman, Richard M.
Voles (Cricetidae) cause extensive damage to a variety of crops throughout much of the Northern Hemisphere. The removal of vegetation from crop fields at the end of the growing season, combined with a subsequent burrow fumigant application of aluminum phosphide, has the potential to substantially curtail vole activity but has not been thoroughly examined. We set up a study to test the impact of these management tools in perennial globe artichoke (Cynara cardunculus var. scolymus) fields in Monterey County, CA, during 2010 and 2011, to determine their potential utility as part of an integrated pest management (IPM) program for managing California voles (Microtus californicus). We used both chewing indices and mortality estimates derived via radiotelemetry to assess the efficacy of aboveground vegetation removal and aluminum phosphide applications on vole abundance. We determined the impact of plowing artichoke fields on vole activity as well. Both removal of vegetation and applications of aluminum phosphide substantially reduced vole presence within treated fields. Plowing also reduced vole abundance to the point of little residual activity following treatment. These management practices appear to be effective at eliminating voles from crop fields. Combining these tools with management practices designed to slow down reinvasion by neighboring vole populations (e.g., barriers, repellents, traps) has the potential to substantially reduce farmer reliance on rodenticides for vole management, although rodenticides will still be needed to curtail populations that reestablish within crop fields. Such an IPM approach should substantially benefit both farmers and agro-ecosystems.
显示更多 [+] 显示较少 [-]Effects of Spartina alterniflora invasion on quality of the red-crowned crane (Grus japonensis) wintering habitat 全文
2019
Wang, Juan | Liu, Hongyu | Li, Yufeng | Liu, Ling | Xie, Fufu | Lou, Cairong | Zhang, Huabing
The core zone of the Yancheng National Natural Reserve (YNNR) in China is the largest wintering habitat of red-crowned cranes (cranes) in the world. However, the invasion of Spartina alterniflora (S. alterniflora) not only changed the original landscape structure of the wetlands but also impacted the cranes’ habitats in the YNNR. In this paper, field investigation data and landscape pattern indices were used to analyze the effects of the S. alterniflora invasion on the habitat quality of wintering cranes. The results indicate that the seep weed (Suaeda salsa) in the natural wetland and the common reed (Phragmites australis) in the managed wetland both provide suitable habitats for cranes. However, the cranes prefer the natural wetland more. The explosive growth of S. alterniflora in the natural area has led to a significant reduction of the cranes’ habitat. The area of crane habitat decreased from 52.07 km² in 2000 to 22.36 km² in 2015. As a result of the S. alterniflora invasion, the benthic biomass has declined, which has negatively impacted the quantity and structure of the food utilized by the cranes. This study has both theoretical and practical significance and provides a scientific basis for protecting the wintering habitat of the red-crowned cranes.
显示更多 [+] 显示较少 [-]Joint toxicity of six common heavy metals to Chlorella pyrenoidosa 全文
2019
Mo, Ling-Yun | Zhao, Dan-Na | Qin, Meng | Qin, Li-Tang | Zeng, Hong-Hu | Liang, Yan-Peng
Six common heavy metals (Ni, Fe, Zn, Pb, Cd, and Cr) in the water environment were selected to present five groups of binary mixture systems (Ni-Fe, Ni-Zn, Ni-Pb, Ni-Cd, and Ni-Cr) through a direct equipartition ray design. Microplate toxicity analysis based on Chlorella pyrenoidosa measured the 96-h joint toxicities of the binary mixtures. Toxicity interaction of the binary mixture was analyzed by comparing the observed toxicity data with the reference model (concentration addition). The results indicated that Ni-Fe, Ni-Pb, and Ni-Cr mixtures showed additive effects at concentration tested. It was indicated that Ni-Zn and Ni-Cd mixtures presented additive effects at low concentrations whereas synergistic effects were seen at high concentrations.
显示更多 [+] 显示较少 [-]Fraction distribution of arsenic in different-sized atmospheric particulate matters 全文
2019
Xie, Jiao-Jiao | Yuan, Chun-Gang | Xie, Jin | Shen, Yi Wen | Zha, Da-Wen | Zhang, Ke-Gang | Zhu, Hong-tao
The sequential extraction method was used to determine the fraction of arsenic (As) in different-sized particulate matters (PMs) (i.e., PM₂.₅, PM₁₀, and total suspended particles (TSP)). Samples were collected from Baoding, a typical medium-sized city with the serious haze pollution in China. The bioavailabilities of As in the samples were estimated based on the fraction results. A large percentage of fine particles were detected in TSP, with the average PM₂.₅/PM₁₀ and PM₁₀/TSP ratios all above 0.69. The total concentrations of As in PM₂.₅, PM₁₀, and TSP samples were in the range of 4.5–296.4, 14.1–708.0, and 32.8–798.0 ng m⁻³, respectively. The mass percentages of As in PM₂.₅, PM₂.₅–₁₀, and PM₁₀–₁₀₀ were calculated; the results indicated that As tended to concentrate in fine particles. PM-bound As mainly presented in the nonspecifically sorbed fraction (F1) during all of the sampling periods. The percentages of F1-As and bioavailability of As were higher in PM₂.₅, followed by PM₁₀ and TSP. By contrast, the residual fraction (F5-As) contents declined in the order of TSP > PM₁₀ > PM₂.₅. Significant differences in the speciation and bioavailability of As in different-sized PMs were found, and the influence of particle size on the speciation and bioavailability of As in PMs was verified. Fine particles adsorbed more As with higher bioavailability, and potentially led to more serious adverse effects on human health than the larger ones.
显示更多 [+] 显示较少 [-]Soil properties and cultivars determine heavy metal accumulation in rice grain and cultivars respond differently to Cd stress 全文
2019
Li, Dongqin | Wang, Lili | Wang, Yahui | Li, Huashou | Chen, Guikui
Field and pot experiments were conducted to evaluate the factors affecting heavy metal (HM) accumulation in rice grain and subsequently to explore their cultivar difference when exposed to Cd. Forty-seven paired soil and rice cultivar samples were collected from Jiangxi province, China. The contents of Cd, Cu, Zn, Pb, Cr, and Ni in soils and grains were determined. It showed that among these metals, Cr and Cd were the dominant contaminants in samples from the test areas, with 100.0% and 59.6% of all grain samples exceeding the maximum permissible concentration. Random forest analysis showed that soil pH, soil organic matter (SOM), Fe fraction and cultivar were four most important factors affecting HMs accumulation in grain. Based on bioconcentration factors, two cultivars with high Cd (HCd) accumulation ability and two cultivars with low Cd (LCd) accumulation ability in rice grain were chosen to explore their physiological and growth responses when exposed to 0, 50, 100 and 1000 μmol L⁻¹ Cd. The results showed that the Cd phytotoxicity is Cd level- and cultivar-dependent. The height and weight decreased, while Cd accumulation increased in shoot and root for the four rice cultivars with the increasing of Cd content. The HCd cultivars showed less membrane damage, higher superoxide dismutase (SOD) activity and higher Cd accumulation than that of LCd cultivars. In conclusion, heavy metal accumulation in rice grain is soil property- and cultivar-dependent. And different rice cultivars respond differently to Cd stress.
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