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Modelling local uncertainty in relations between birth weight and air quality within an urban area: combining geographically weighted regression with geostatistical simulation Texte intégral
2018
Ribeiro, Manuel Castro | Pereira, Maria João
In this study, we combine known methods to present a new approach to assess local distributions of estimated parameters measuring associations between air quality and birth weight in the urban area of Sines (Portugal). To model exposure and capture short-distance variations in air quality, we use a Regression Kriging estimator combining air quality point data with land use auxiliary data. To assess uncertainty of exposure, the Kriging estimator is incorporated in a sequential Gaussian simulation algorithm (sGs) providing a set of simulated exposure maps with similar spatial structural dependence and statistical properties of observed data. Following the completion of the simulation runs, we fit a geographically weighted generalized linear model (GWGLM) for each mother’s place of residence, using observed health data and simulated exposure data, and repeat this procedure for each simulated map. Once the fit of GWGLM with all exposure maps is finished, we take the distribution of local estimated parameters measuring associations between exposure and birth weight, thus providing a measure of uncertainty in the local estimates. Results reveal that the distribution of local parameters did not vary substantially. Combining both methods (GWGLM and sGs), however, we are able to incorporate local uncertainty on the estimated associations providing an additional tool for analysis of the impacts of place in health.
Afficher plus [+] Moins [-]Pd based in situ AOPs with heterogeneous catalyst of FeMgAl layered double hydrotalcite for the degradation of bisphenol A and landfill leachate through multiple pathways Texte intégral
2018
Liao, Zhuwei | Dai, Shijing | Long, Sijie | Yu, Yingjian | ʻAlī, Jawād | Wang, Huabin | Chen, Zhulei | Chen, Zhuqi
In situ degradation of organic contaminants by Pd and electro-generated H₂ and O₂ overcomes the drawbacks to traditional Fenton process, and conducting heterogeneous catalyst of FeMgAl layered double hydrotalcite (LDH) further improved the efficiency and stability. Using bisphenol A (BPA) as the model contaminants, 90% removal can be achieved with 1200 mg/L Pd/Al₂O₃ and FeMgAl-2. The reusability was satisfying due to the very limited leaching of Fe ions at 0.1 ppm level. FeMgAl also amplified the window of pH for Pd-catalyzed in situ advanced oxidation processes (AOPs) from 3 by homogenous Fe(II) to 3–7 by FeMgAl LDH. The COD of landfill leachate effluent of the MBR system removed by about 52.3% by this system by the initial pH was 5. Characterizations revealed the distinguishing features associated with LDH structure such as large surface area, good stability, basic character, and strong linage among active sites were accounted for the remarkable performances over a wide pH window. Five reactive intermediates were observed and multiple degradation pathways were proposed in Pd-catalyzed in situ AOP for the first time. Interestingly, because of the unique role of Pd catalyst, these degradation pathways were clearly distinguished from traditional Fenton or Fenton-like AOPs and may provide a new approach of in situ heterogeneous AOPs for refractory contaminants in future.
Afficher plus [+] Moins [-]Professional quality of life, wellness education, and coping strategies among emergency physicians Texte intégral
2018
El-Shafei, DaliaA. | Abdelsalam, AmiraE. | Hammam, RehabA. M. | Elgohary, Hayam
Professional quality of life (ProQOL) is affected by and affects professional well-being and performance. The objectives of this study are to identify risk factors of ProQOL among EM physicians in Zagazig University hospitals (ZUHs), to detect the relationship between ProQOL and coping strategies, and to measure the implication of the Worksite Wellness Education (WWE) program on improving knowledge skills, ProQOL, and coping. An intervention study was conducted among 108 EM physicians at ZUHs through two stages: assessing ProQOL subscales (CS, BO, and STS) and coping strategies and conducting the WWE program. A pre–post-test design was used in the evaluation. CS was higher among the older age group, smokers, nighttime sleepers, and hobbies’ practitioners. Coping strategies carried out by EM physicians to overcome stress and their ProQOL scores were improved significantly post program. ProQOL has multiple factors that affect it. Applying the WWE program will address this concept and may raise awareness about how to cope with work stressors.
Afficher plus [+] Moins [-]Defluoridation using novel chemically treated carbonized bone meal: batch and dynamic performance with scale-up studies Texte intégral
2018
Chatterjee, Somak | Mukherjee, Munmun | De, Sirshendu
Novel defluoridating adsorbent was synthesized by chemical treatment of carbonized bone meal using aluminum sulfate and calcium oxide. Precursor for chemical treatment was prepared by partial carbonization of raw bone meal at 550 °C for 4 h. Maximum fluoride removal capacity was 150 mg/g when carbonized bone meal (100 g/L) was treated with aluminum sulfate (500 g/L) and calcium oxide (15 g/L). Morphological analysis revealed formation of a coating layer consisting of aluminum compounds on the precursor surface. This was verified by stretching frequency of aluminum hydroxide (602 cm⁻¹) in the infrared spectra. Presence of hydroxylapatite (2θ = 30° and 2θ = 24°) and aluminum mineral phases (2θ = 44°) in the adsorbent were identified from the X-ray diffractograms. Adsorption capacity decreased from 150 mg/g (30 °C) to 120 mg/g (50 °C) indicating exothermic adsorption. Adsorption experiments under batch kinetic mode were simulated using shrinking core model. Effective fluoride diffusivity in the adsorbent and the mass transfer coefficient were estimated as 5.8 × 10⁻¹² m²/s and 9 × 10⁻⁴ m/s, respectively. Desorption was maximum at basic pH and desorption efficiency was decreased by 31% after third cycle. Dynamic filtration with artificially fluoride-spiked solution showed that the empty bed contact time for a packed column with equal weight of carbonized and chemically treated adsorbent was 4.7 min and number of bed volumes treated (till WHO limit of 1.5 mg/L) was 340 for a column of 3-cm diameter and 18-cm length. The system was successfully tested using contaminated groundwater from an affected area. Fixed-bed column experiments were simulated from the first principles using convective pore diffusion-adsorption model for both synthetic solution and contaminated groundwater. Axial dispersion coefficient was found to be one order of magnitude less than the pore diffusivity indicating dominance of fluoride diffusion within porous network of adsorbent. The developed adsorbent exhibited antibacterial property as well.
Afficher plus [+] Moins [-]Adsorptive performance of coal-based magnetic activated carbon for cyclic volatile methylsiloxanes from landfill leachate Texte intégral
2018
Zhang, Chunhui | Jiang, Shan | Wenwen,
Bituminous coal-based magnetic activated carbon (MAC) was prepared, characterized, and used successfully for removal of cyclic volatile methylsiloxanes (cVMSs) from treated landfill leachate. Batch adsorption studies were performed at different adsorption dosages and contact times. With adsorptive dosage of 0.75 g/L and contact time of 60 min, the removal efficiencies achieved by MAC for octamethylcyclotetrasiloxane (D₄), decamethylcyclopentasiloxane (D₅), and dodecamethylcyclohexasiloxane (D₆) are 100, 82.8, and 71.4%, respectively. The specific magnetization coefficients of MAC before and after adsorption are 4.6 × 10⁻⁷ and 5.2 × 10⁻⁷ m³/kg, between 1.26 × 10⁻⁷ and 3.8 × 10⁻⁵ m³/kg, which suggests that MAC can be recycled by the high-intensity magnetic separators.
Afficher plus [+] Moins [-]Preventive use of berberine in inhibition of lead-induced renal injury in rats Texte intégral
2018
Hasanein, Parisa | Riahi, Hassan
The kidney is one of the main organs affected by lead toxicity. We investigated the effects of berberine on lead-induced nephrotoxicity in adult male Wistar rats. Animals received an aqueous solution of lead acetate (500 mg Pb/L in the drinking water) and/or berberine (50 mg/kg, i.g.) for 8 weeks. Lead caused an increase in malondialdehyde (P < 0.001) and total oxidant status (P < 0.01), and a decrease in reduced glutathione (P < 0.001), catalase (P < 0.01), superoxide dismutase (P < 0.001), and total antioxidant capacity (P < 0.05). Berberine prevented the prooxidant and antioxidant imbalance induced by lead (P < 0.001). Berberine corrected the increased relative kidney weight (P < 0.05) and biomarkers of renal function (creatinine (P < 0.001), urea (P < 0.05), uric acid (P < 0.001), albumin (P < 0.01), and total protein (P < 0.05)) in lead group. It also attenuated lead-induced abnormal renal structure. The results confirmed renoprotective effects of berberine in an animal model of lead-induced nephrotoxicity by molecular, biochemical, and histopathological analysis through inhibiting lipid peroxidation and enhancing antioxidant defense system mechanisms. Therefore, berberine makes a good candidate to protect against the deleterious effect of chronic lead intoxication.
Afficher plus [+] Moins [-]Toxic effects of linear alkylbenzene sulfonate on Chara vulgaris L Texte intégral
2018
Liu, Nian | Wu, Zhonghua
Linear alkylbenzene sulfonate (LAS) is a common organic pollutant in freshwater environments. Studies have shown that the toxicity of LAS to aquatic plants is directly related to the LAS concentration and depends on the plant species. A 2-week exposure experiment was designed to investigate the toxicity of LAS for the submerged plant Chara vulgaris L. and focused on the effects on growth, photosynthetic pigment content, and antioxidant enzyme activity. The results showed that when exposed to lower LAS doses (≤ 1.0 mg l⁻¹), the dry weight of C. vulgaris was significantly reduced. Compared to those of the control group, superoxide dismutase (SOD) and peroxidase (POD) activities significantly increased, while no significant effect was observed for catalase (CAT) activity. Malondialdehyde (MDA) content significantly increased in the LAS treatment groups except for the LAS concentration of 1.0 mg l⁻¹. The content of carotenoids was significantly lower in plant groups exposed to lower concentrations of LAS, while carotenoid content significantly increased at the highest concentration of LAS (5.0 mg l⁻¹). LAS treatment did not significantly affect chlorophyll a and b or total chlorophyll content. The results showed that 5.0 mg l⁻¹ causes some oxidative damage to C. vulgaris but that this concentration was far below the lethal concentration of LAS to C. vulgaris and did not produce severe effects on growth. C. vulgaris plants had some resistance to LAS stress (in the group with ≤ 5.0 mg l⁻¹). SOD, POD, and carotenoids were more sensitive to the effects of LAS stress and may be considered as response indicators for LAS stress.
Afficher plus [+] Moins [-]The impact of foreign direct investment on CO2 emissions in Turkey: new evidence from cointegration and bootstrap causality analysis Texte intégral
2018
Koçak, Emrah | Şarkgüneşi, Aykut
Pollution haven hypothesis (PHH), which is defined as foreign direct investment inducing a raising impact on the pollution level in the hosting country, is lately a subject of discussion in the field of economics. This study, within the scope of related discussion, aims to look into the potential impact of foreign direct investments on CO₂ emission in Turkey in 1974–2013 period using environmental Kuznets curve (EKC) model. For this purpose, Maki (Econ Model 29(5):2011–2015, 2012) structural break cointegration test, Stock and Watson (Econometrica 61:783–820, 1993) dynamic ordinary least square estimator (DOLS), and Hacker and Hatemi-J (J Econ Stud 39(2):144–160, 2012) bootstrap test for causality method are used. Research results indicate the existence of a long-term balance relationship between FDI, economic growth, energy usage, and CO₂ emission. As per this relationship, in Turkey, (1) the potential impact of FDI on CO₂ emission is positive. This result shows that PHH is valid in Turkey. (2) Moreover, this is not a one-way relationship; the changes in CO₂ emission also affect FDI entries. (3) The results also provide evidence for the existence of the EKC hypothesis in Turkey. Within the frame of related findings, the study concludes several polities and presents various suggestions.
Afficher plus [+] Moins [-]Decoupling effect and forecasting of economic growth and energy structure under the peak constraint of carbon emissions in China Texte intégral
2018
Wang, Shijin | Li, Cunfang | Yang, Lizhu
The decoupling effect between economic growth and energy structure was quantitatively analyzed from 1999 to 2014 across China. The results showed it existed weak decoupling effects in most regions. Based on the analysis of the influence of energy structure on carbon intensity, using scenario simulation methods and Markov chain modeling, the carbon intensity was predicted for China in 2020. The impact of energy structure adjustment on the carbon intensity to meet China’s carbon target by 18 possible scenarios are calculated. Furthermore, the peak value of carbon emissions was also calculated in 2030. The results showed that the carbon intensity predicted for China in 2020 can be achieved regardless of whether the energy structure was adjusted or not when energy saving and carbon reduction policies maintained with economic growth at 6–7%. Moreover, given fixed energy structure growth, for each 1% of economic growth, the carbon intensity will decrease by about 3.5%. Given fixed economic growth, the decrease of energy intensity will be greater if the control of energy consumption is stronger. The effect of energy structure adjustment on the decreasing of carbon intensity will be 4% higher under constraints than without constraints. On average, the contribution of energy structure adjustment to achieving the carbon intensity target was calculated as 4% higher than that with constraints. In addition, given relatively fixed economic growth at 6–7%, the peak value of carbon emission in 2030 was calculated as 13.209 billion tons with constraints and 14.38 billion tons without constraints.
Afficher plus [+] Moins [-]Effects of combined exposure to perfluoroalkyl acids and heavy metals on bioaccumulation and subcellular distribution in earthworms (Eisenia fetida) from co-contaminated soil Texte intégral
2018
Zhao, Shuyan | Yang, Qiao | Wang, Bohui | Peng, Yihong | Zhan, Jingjing | Liu, Lifen
The effects of combined exposure to perfluoroalkyl acids (PFAAs) and heavy metals (HMs) including cadmium (Cd), copper (Cu), zinc (Zn), nickel (Ni), and lead (Pb) on earthworms (Eisenia fetida) were investigated. The results have demonstrated that the concentrations of labile acid exchangeable Cd, Zn, Ni, Pb, and Cu in soil were enhanced in addition of PFAAs. With PFAAs, the uptake of Cd, Zn, Ni, Pb, and Cu in earthworms was increased compared to those without PFAAs with the order of Cd > Zn > Pb > Ni > Cu. In the presence of HMs, the average biota-to-soil accumulation factors (BSAFs) of PFAAs in earthworms were decreased by 0.498–0.729 times for perfluorooctane sulfonate (PFOS) and 0.606–0.978 times for perfluorooctanoic acid (PFOA), indicating decrease rates of PFOS were higher than those of PFOA. And different levels of HMs led to insignificant different responses on the inhibiting effects of PFAAs uptake in earthworms. The increase of Cd in fraction C (associated with cytosol) and decrease of PFAAs in fraction C and fraction P (associated with tissue fragments, cell membranes, and intact cells) especially for fraction C were revealed when they were combined, suggesting cytosolic PFAAs and Cd were susceptibly mutual effected. This study indicated that PFAAs and metals mutually affected their bioaccumulation and subcellular distribution in earthworms, which will help to understand the fate and risks of PFAAs and metals in co-contaminated soil.
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