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Water resources and tourism development in South Asia: an application of dynamic common correlated effect (DCCE) model Full text
2020
Meo, Muhammad Saeed | Sabir, Saeed Ahmad | Arain, Hira | Nazar, Raima
The current study explores the relationship between water resources and tourism in South Asia for the period of 1995–2017. The study employs the CIPS unit root test for stationarity of the variables and the CD test for cross-sectional dependence among cross-sectional units. As for the long-run parameters, a novel technique, known as dynamic common correlated effect (DCCE) model, is used which was recently developed by Chudik and Pesaran (J Econ 188:393–420, 2015b). The outcomes from the DCCE method suggest that water resources have a positive impact on tourism in South Asia. It is also proven that ignoring cross-sectional dependence among the cross-sectional units may bring about misleading outcomes. The findings of the study can be helpful for policymakers to understand the role of water resources in boosting tourism and contributing to the economic prosperity of South Asian countries.
Show more [+] Less [-]Energy capacity, industrial production, and the environment: an empirical analysis from Pakistan Full text
2020
Mahmood, Muhammad Tariq | Shahab, Sadaf | Hafeez, Muhammad
This paper aims to find out relationships among the energy, environment, and the industrial production for a developing country which is in earlier stages of development. It also tests a few contradicting hypotheses to find the possible shape of an environmental Kuznets curve. Using the time series data, the study finds robust long-run relationships between energy, environment, and industrial production for Pakistan. The scale economy is also assumed. It is also found that the capital and labor elasticities of income show increasing returns in the presence of energy and emission variables. It finds evidence of EKC in a quadratic restricted model but not in a cubic function. This analysis implies that the focus of policy authorities should be to persuade environment-friendly energy resources. After an initial stage of economic development, society has to take serious measure to tackle the issues of environmental degradation.
Show more [+] Less [-]Biological responses at the interface of Ti-doped diamond-like carbon surfaces for indoor environment application Full text
2020
Bouabibsa, Imane | Alhussein, Akram | Lamri, Salim | Sanchette, Frederic | Rtimi, Sami
Diamond-like carbon (DLC) and titanium-doped DLC coatings were prepared by hybrid PECVD/direct current magnetron sputtering (DCMS). In this study, we show that the operating conditions of titanium-doped DLC coatings used for implants in surgical devices significantly modify their surface properties and consequently their interaction with cells. The coatings showed uniform distribution on the substrate and their biocompatibility was tested by way of rat calvaria osteoblasts. Doping DLC with Ti changed the roughness and wettability of the film interface. The autoclaving of the samples led to the surface oxidation and the formation of TiO₂ on the top-most layers of Ti-doped DLC. This was quantitatively assessed by X-ray photoelectron spectroscopy (XPS) and revealed the presence of Ti³⁺ and Ti⁴⁺ species in redox reactions during their interactions with cells. By XPS analysis, the oxidative carbonaceous species C=O and O=C–C were detected during the bacterial inactivation. Reactive oxygen species (ROS) were identified on the sputtered samples and the ⦁OH radical was identified as the most important oxidative radical intermediate leading to bacterial disinfection. The position of the intra-gap of the oxidized C species is suggested within the TiO₂ bandgap.
Show more [+] Less [-]Knowledge and attitude toward waterpipe smoking: scale validation and correlates in the Lebanese adult population Full text
2020
Farah, Rita | Haddad, Chadia | Sacre, Hala | Hallit, Souheil | Salameh, Pascale
The World Health Organization declared waterpipe smoking as a growing public health concern. Our study aimed to assess waterpipe smoking knowledge and attitude among current waterpipe smokers in comparison with nonsmokers and to evaluate its association with current and cumulative waterpipe smoking. A cross-sectional study was carried between May and December 2018 using a multistage cluster sample across Lebanon. Nonsmokers or exclusive current waterpipe smokers were eligible to participate. A total of 4046 adult individuals participated in the study, 38.3% (n = 1550) being current waterpipe smokers. Current waterpipe smoking was positively associated with female gender [adjusted odds ratio (aOR) 1.79, 95%CI 1.40–2.28] and having a mother who is a regular smoker (aOR 1.47, 95%CI 1.15–1.88) while it was negatively associated with better knowledge about waterpipe smoking harm (aOR 0.95, 95%CI 0.93–0.97) and positive attitude toward waterpipe smoking ban (aOR 0.98, 95%CI 0.96–0.99). Cumulative waterpipe smoking was negatively associated with female gender (β = − 0.012), higher education level (β = − 0.28), and positive attitude toward WPS ban (β = − 0.06). Waterpipe smoking is largely present among the Lebanese population, with waterpipe smokers showing lower knowledge about harm and more intolerant attitude about banning. Health awareness supported by media campaigns and governmental initiatives should be conducted to educate people and change their perceptions regarding waterpipe smoking.
Show more [+] Less [-]Carbon-to-nitrogen ratio influence on the performance of bioretention for wastewater treatment Full text
2020
Wang, Yajun | Singh, Rajendra Prasad | Geng, Chongchong | Fu, Dafang
Bioretention cell (BRC), bioretention cell with microbial fuel cell (BRC-MFC), and an enhanced combined BRC-MFC system with bimetallic zero-valent iron (BRC-MFC-BZVI) were implemented in current study to treat the domestic wastewater. Nitrogen removal characteristics of three systems were investigated by adjusting influent carbon/nitrogen ratio (C/N ratio of 2.54–19.36). Results revealed that the nitrification and denitrification performances were mainly influenced by organic matter and system combination, which further affected nitrogen removal. When the influent C/N ratio was between 2 to 3, compared with BRC system, in BRC-MFC and BRC-MFC-BZVI system, chemical oxygen demand (COD), total nitrogen (TN), and ammonical nitrogen (NH₄⁺-N) removal efficiencies were still reached to 83.04%, 61.06%, and 42.26% and 86.53%, 43.61%, and 50.99% respectively, which simultaneously achieved high-efficiency of organic matter and nitrogen removal. The efficient supply of electrons in the BRC-MFC and BRC-MFC-BZVI processes was the main reason to achieve profound denitrification removal under the condition of low C/N. Removal rates of nitrate (NO₃⁻−N) and nitrite (NO₂⁻−N) were relatively higher due to microbial-driven redox reactions caused by driving electrons to flow in the closed circuit of metal wire connection. Moreover, phylogenetic diversity of bacterial communities mainly induced the catalytic iron, which further enhanced biological nitrogen reduction. The maximum efficient removal of organic matter (OM), TN, and NH4 + −N were obtained in the BRC-MFC-BZVI system, which were 98.42% (C/N = 10.42), 55.61% (C/N = 4.16), and 61.13% (C/N = 4.16), respectively.
Show more [+] Less [-]Relationship between air pollution and hospitalizations for congestive heart failure in elderly people in the city of São Paulo Full text
2020
de Aguiar Pontes Pamplona, Ysabely | Arbex, Marcos Abdo | Braga, Alfésio Luís Ferreira | Pereira, Luiz Alberto Amador | Martins, Lourdes Conceição
To evaluate the effects of air pollutants on hospitalizations of elderly people for congestive heart failure (CHF) in the city of São Paulo, stratified by sex, exploring lag structures, from 2000 to 2013. Ecological time series study using information on hospitalization of elderly patients for CHF (ICD-10th: I50) obtained from DATASUS for the city of São Paulo. Information on O₃, PM₁₀, NO₂, SO₂, CO, temperature and humidity was obtained from CETESB. Descriptive analyses, Pearson correlation, and generalized linear Poisson regression model were applied to estimate the effects of pollutants. The interquartile variations of O₃ (52.45 μg/m³), PM₁₀ (24.28 μg/m³), NO₂ (7.63 μg/m³), SO₂ (50.22 μg/m³), and CO (1.28 ppm) were associated with increased hospitalizations for CHF. Air pollutants continue to be a factor that contributes to the increase in the number of hospitalizations due to CHF.
Show more [+] Less [-]Particulate matter on foliage of Betula pendula, Quercus robur, and Tilia cordata: deposition and ecophysiology Full text
2020
Łukowski, Adrian | Popek, Robert | Karolewski, Piotr
Trees in urban and industrial areas significantly help to limit the amount of particulate matter (PM) suspended in the air, but PM has a negative impact on their life. The amount of PM gathered on leaves depends on quantity, size, and morphology of leaves and can also be increased by the presence of epicuticular waxes, in which PM can become stuck or immersed. In this study, we determined the ability of PM to accumulate on leaves in relation to the species of tree and PM source. We tested saplings of three common European tree species (Betula pendula, Quercus robur, and Tilia cordata) by experimentally polluting them with PM from different sources (cement, construction, and roadside PM), and then assessing the effects of PM on plant growth and ecophysiology. In all studied species, we have found two types of PM accumulation: a layer on the leaf surface and an in-wax layer. Results showed that the studied species accumulate PM on their leaf blade, reducing the efficiency of its photosynthetic apparatus, which in a broader sense can be considered a reduction in the plants’ normal functioning. Saplings of Q. robur suffered the least, whereas B. pendula (especially photosynthetic rate and conductivity) and T. cordata (especially increase in leader shoot length) exhibited greater negative effects. The foliage of B. pendula collected the most PM, followed by Q. robur, and then T. cordata, regardless of the dust’s source. All tested species showed a tendency for higher wax production when growing under PM pollution stress. We believe that, potentially, B. pendula best enhances the quality of the PM-contaminated environment; however, faster leaf fall, reduced productivity, and worse quality of wood should be considered in urban forest management.
Show more [+] Less [-]Revealing the active period and type of tetracycline stress on Chinese cabbage (Brassica rapa L.) during seed germination and post-germination Full text
2020
Luo, Yuan | Liang, Jie | Zeng, Guangming | Zhang, Yafei | Cheng, Xiaojuan | Jiang, Longbo | Xing, Wenle | Tang, Ning
Stresses of antibiotics can cause strains (i.e. effects) on seed at germination and post-germination stages. But there is a lack of research on the period and type of the effects at present. In this study, Chinese cabbage (Brassica rapa L.), a commonly used crop, was selected to investigate the effect of tetracycline (TC), a major-use antibiotic, on its seed during different periods of the stages. Results showed that there were no significant differences among the germination energy (GE) of control (CK) and treatments, but radicle length (RL) of the treatments, the exposure to TC at post-germination stage (i.e. radicle elongation stage), was all significantly less than that of CK. The initial stage of radicle elongation was the earliest and most sensitive period at which the stress of TC caused the plastic effect on seed. Moreover, the action of TC stress on seed did not have a delayed characteristic. The result of RL was identical to the leakage of intracellular substances at radicle fast elongation stage, but not the Evan’s blue trapped by radicle. We concluded that TC inhibited the elongation of radicle through weakening the cellular metabolic activity rather than leading to the loss of cellular membrane integrity. It should be paid more attention to the phytotoxicity of TC in the field due to its active characteristics revealed in our study.
Show more [+] Less [-]Influence of particle size distribution on anaerobic degradation of phenol and analysis of methanogenic microbial community Full text
2020
Wang, Jing | Wu, Benteng | Sierra, Julian Muñoz | He, Chunhua | Hu, Zhenhu | Wang, Wei
Sludge morphology considerably affects the mechanism underlying microbial anaerobic degradation of phenol. Here, we assessed the phenol degradation rate, specific methanogenic activity, electron transport activity, coenzyme F₄₂₀ concentration, and microbial community structure of five phenol-degrading sludge of varying particle sizes (i.e., < 20, 20–50, 50–100, 100–200, and > 200 μm). The results indicated an increase in phenol degradation rate and microbial community structure that distinctly correlated with an increase in sludge particle size. Although the sludge with the smallest particle size (< 20 μm) showed the lowest phenol degradation rate (9.3 mg COD·gVSS⁻¹ day⁻¹), its methanogenic activity with propionic acid, butyric acid, and H₂/CO₂ as substrates was the best, and the concentration of coenzyme F₄₂₀ was the highest. The small particle size sludge did not contain abundant syntrophic bacteria or hydrogenotrophic methanogens, but contained abundant acetoclastic methanogens. Moreover, the floc sizes of the different sludge varied in important phenol-degrading bacteria and archaea, which may dominate the synergistic mechanism. This study provides a new perspective on the role of sludge floc size on the anaerobic digestion of phenol.
Show more [+] Less [-]Polycyclic musk fragrances (PMFs) in wastewater and activated sludge: analytical protocol and application to a real case study Full text
2020
Tasselli, Stefano | Guzzella, Licia
Two different analytical methods for the determination of polycyclic musk fragrances (PMFs) in wastewater and in activated sludge were developed. PMFs in filtered water samples were determined by gas chromatography coupled with a triple-quadrupole mass spectrometer in selected reaction monitoring (SRM) mode. Activated sludge samples were extracted using an ultrasonic bath and analysed using a GC-Ion trap. The developed methods respected a linear model (R² > 0.995). Detection limits of selected compounds (Celestolide, Galaxolide, Galaxolidone, Phantolide and Tonalide) varied from 1.7 to 80 ng L⁻¹ for water and from 0.1 ng g⁻¹ to 210 ng g⁻¹ for activated sludge considering laboratory contamination for each PMF. Recovery studies were performed on spiked water samples and, for sludges, on procedural blanks, showing recoveries above 70% for all the considered compounds, while recovery of the internal standard was always above limit of acceptance (30%). Proposed methods were used to determine PMFs concentrations in wastewaters and activated sludges of a wastewater treatment plant (WWTP) located in Northern Italy. Concentrations in the range of μg L⁻¹ of Galaxolide and of its metabolite Galaxolidone were detected even in the WWTP effluent. Biotransformation of Galaxolide into Galaxolidone occurred during biological treatment with the consequent release of this compound through WWTP effluents. In activated sludges, concentrations of all PMFs except Galaxolidone were one order of magnitude higher than wastewaters, as expected according to their physicochemical properties. Present wastewater treatment technologies were confirmed to not be efficient in removing PMFs from influent wastewaters since with only ≃ 30% of Celestolide and Tonalide were removed.
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