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Signifying the imperative nexus between climate change and information and communication technology development: a case from Pakistan Полный текст
2020
Shehzad, Khurram | Xiaoxing, Liu | Sarfraz, Muddassar | Zulfiqar, Muhammad
The globe has faced technological affluence that enormously revolutionized the lives of humankind. Today, the manufacturing process of the energy sector, production sector, agriculture sector, and service sector is exclusively or partially based on ICT tools. The key intention of this investigation is to find out the impacts of the utilization of ICT on CO₂ emission. However, this investigation also evaluates the influence of investment in ICT and the trade of ICT tools on CO₂ emission. Further, the estimation examined the subsistence of environment Kuznets curve (EKC) theory, for the nation of Pakistan. The investigation employed an autoregressive distributed lag (ARDL) model and found that the utilization of ICT has a negative impact on CO₂ emission. Moreover, the long-run results revealed that the import of ICT equipment is more beneficial for the environment quality of Pakistan. However, ICT apparatus manufactured in Pakistan might produce electronic waste due to non-utilization of green technology. The study reported bidirectional causality between ICT and CO₂ emission. These results point towards that the emergence of ICT in industries and daily life possesses a significant and positive role in climate change in Pakistan. Also, this study corroborates the veracity of EKC in Pakistan.
Показать больше [+] Меньше [-]Does ozone exposure affect herbivore-induced plant volatile emissions differently in wild and cultivated plants? Полный текст
2020
Brosset, Agnès | Saunier, Amélie | Kivimäenpää, Minna | Blande, James D.
Concentrations of tropospheric ozone have more than doubled in the Northern Hemisphere since pre-industrial times. Plant responses to single abiotic or biotic stresses, such as ozone exposure and herbivore-feeding, have received substantial attention, especially for cultivated plants. Modern cultivated plants have been subjected to selective breeding that has altered plant chemical defences. To understand how ozone might affect plant responses to herbivore-feeding in wild and cultivated plants, we studied the volatile emissions of brassicaceous plants after exposure to ambient (~ 15 ppb) or elevated ozone (80 ppb), with and without Plutella xylostella larvae-feeding. Results indicated that most of the wild and cultivated plants increased volatile emissions in response to herbivore-feeding. Ozone alone had a weaker and less consistent effect on volatile emissions, but appeared to have a greater effect on wild plants than cultivated plants. This study highlights that closely related species of the Brassicaceae have variable responses to ozone and herbivore-feeding stresses and indicates that the effect of ozone may be stronger in wild than cultivated plants. Further studies should investigate the mechanisms by which elevated ozone modulates plant volatile emissions in conjunction with biotic stressors.
Показать больше [+] Меньше [-]DNA methylation of JAK3/STAT5/PPARγ regulated the changes of lipid levels induced by di (2-ethylhexyl) phthalate and high-fat diet in adolescent rats Полный текст
2020
Xu, Qi | Qi, Wen | Zhang, Yuezhu | Wang, Qi | Ding, Shuang | Han, Xu | Zhao, Yaming | Song, Xinyue | Zhao, Tianyang | Zhou, Liting | Ye, Lin
Di (2-ethylhexyl) phthalate (DEHP) and high-fat diet (HFD) could induce lipid metabolic disorder. This study was undertaken to identify the effect of DNA methylation of JAK3/STAT5/PPARγ on lipid metabolic disorder induced by DEHP and HFD. Wistar rats were divided into a normal diet (ND) group and HFD group. Each diet group treated with DEHP (0, 5, 50, 500 mg/kg/d) for 8 weeks’ gavage. The DNA-methylated levels of PPARγ, JAK3, STAT5a, and STAT5b in rats’ livers and adipose were analyzed with MethylTarget. The lipid levels of rats’ livers and adipose were detected with ELISA. Results showed in ND group that the DNA methylation levels of PPARγ, JAK3 in livers, and STAT5b in adipose were lower in 500 mg/kg/d group than the control. And the level of total cholesterol (TC) in adipose was higher in 500 mg/kg/d group than the control. In HFD group, the DNA methylation level of JAK3 was the lowest in livers and the highest in adipose in 50 mg/kg/d group. And the level of TC in livers was the lowest in 50 mg/kg/d group. In the 500 mg/kg/d group, the DNA methylation level of STAT5b was lower in livers and higher in adipose in HFD group than that in ND group. And the levels of TC in livers were lower in HFD group than those in ND group. Therefore, DNA methylation of JAK3/STAT5/PPARγ regulated the changes in lipid levels induced by DEHP and HFD in adolescent rats.
Показать больше [+] Меньше [-]Relationship between inward FDI and environmental degradation for Pakistan: an exploration of pollution haven hypothesis through ARDL approach Полный текст
2020
Nadeem, Abdul M. | Ali, Tariq | Khan, Muhammad T. I. | Guo, Zhengquan
In many developing countries, rising pollution and FDI inflows are positively correlated. This paper explores the existence of pollution haven hypothesis in Pakistan by employing the autoregressive distributed lag (ARDL) bounds test on yearly data from 1971 to 2014 for foreign direct investment inflow and four pollutants, i.e., CO₂ emissions, CO₂ emissions from solid fuels, SO₂ emissions, and GHG emissions. In each case, eight different models are tested by incorporating different explanatory variables with foreign direct investment inflow. The outcome of this study shows that in some of the models a positive long-term relationship exists between FDI inflow and CO₂ emissions, CO₂ emissions from solid fuels, and GHG emissions and a negative long-term relationship between FDI inflow and SO₂ emissions. Overall, we found no conclusive evidence of the existence of the pollution haven hypothesis for Pakistan. As Pakistan is taking active measures to attract more FDI, it is essential to introduce appropriate environmental policies and institutional reforms that do not hinder FDI inflows.
Показать больше [+] Меньше [-]Investigation of exhaust emissions of an isolated diesel engine blended with ethylhexyl nitrate using experimental and ANN approach Полный текст
2020
Sevinc, Huseyin | Hazar, Hanbey
Thermal barrier coating (TBC) implementations and oxygenated additives are remarkable issues that may decrease the exhaust emissions of engines. This study examines the effect of chromium oxide (Cr₂O₃) coating and the addition of ethylhexyl nitrate (EHN) on exhaust emissions of a diesel engine. In addition, an artificial neural network (ANN) model was designed which estimates exhaust emissions based on engine speed in order to reduce time, labor, and costs lost in experimental studies, and the performance of the ANN was evaluated. Piston crown and valves of engine were processed with Cr₂O₃. The E3, E6, and E9 blends were produced by blending 3%, 6%, and 9% (vol.) ratios of 2-ethylhexyl nitrate with diesel fuel. Engine speed was used as input parameter and carbon monoxide (CO), nitrogen oxide (NOX), hydrocarbon (HC), and smoke density were used as output parameters. To evaluate the performance of ANN, error rates, and regression (R) values were considered. Experimental results revealed that CO, HC, and smoke density decreased in the CE whereas NOX values increased compared with the UE. The addition of EHN reduced NOX emission and smoke density, whereas it increased CO and HC emissions. The result showed that ANN model can predict the exhaust emissions at a high accuracy rate. The lowest regression results were achieved as 0.98395, 0.99047, 0.99268, and 0.98383 for the CO, NOX, smoke density, and HC, respectively. Moreover, the average R values of NOX, HC, CO, and smoke density were obtained as 0.99767, 0.99131, 0.99396, and 0.99741. The maximum error rates of the estimated outcomes were obtained as 5.25% on average. Graphical abstract
Показать больше [+] Меньше [-]The effect of expected financial performance on corporate environmental responsibility disclosure: evidence from China Полный текст
2020
Zeng, Yanqi | Gulzar, Muhammad Awais | Wang, Zongjun | Zhao, Xinxin
Nowadays, firms spend a great deal of effort on Corporate Environmental Responsibility (CER) disclosure. From prospect theory, firms might disclose more CER information when they fail to achieve expected financial performance of the organization. We have constructed a CER disclosure index based on the “Guidelines for Environmental Information Disclosure of Listed Companies” issued by the Ministry of Environmental Protection of China in 2010. Using content analysis, we analyze 397 Chinese manufacturing Shanghai A-share listed firms from 2011 to 2017 (2090 firm-year observations) to investigate the relationship between corporate expected financial performance and CER disclosure. Our results show that, firstly, when the firm does not achieve the expected performance that is when the actual expectation is lower than the expected performance of the organization, the disclosure of corporate environmental responsibility increases; secondly, we have explored the moderating effect of industry categories; we have found that when firms fail to achieve the expected performance of the organization, light polluting firms are more inclined towards disclosing the environmental responsibility information than heavy polluting firms. Additionally, we have also studied the behavior of corporate environmental responsibility disclosure in the case of analysts expecting performance as a point of reference and got the same results.
Показать больше [+] Меньше [-]Argyrophilic nucleolar organizer regions in oral mucosa cells of crack and cocaine users: a cross-sectional study Полный текст
2020
Góes Rabelo, Rosângela | Salgueiro, Arthur Pias | Visioli, Fernanda | da Silva, Viviane Palmeira | das Graças Alonso Oliveira, Maria | Ribeiro, Daniel Araki | Cury, Patricia Ramos | dos Santos, Jean Nunes
The objective of this study was to analyze and compare the presence of argyrophilic nucleolar organizer regions (AgNORs) in exfoliated cells obtained from the buccal mucosa among crack and cocaine users and non-users by the AgNOR staining technique. Seventy-three males ≥ 18 years were categorized into two groups: 38 crack and/or cocaine users and 35 non-user volunteers. They were interviewed and responded a questionnaire regarding general health and drug addiction. Exfoliative cytology specimens were collected from the clinically intact buccal mucosa, and cytological preparations were fixed and stained by AgNOR technique. The mean number of AgNORs (p = 0.02) and the percentage of epithelial cells with more than 3 (p = 0.01) and 4 (p = 0.04) AgNORs/nucleus were significantly higher in the non-user group. In conclusion, the frequency and diversity of substances present in the drugs—cocaine, crack, and alcohol—consumed by the volunteers of this study may have influenced the number of AgNORs and the response to damage and consequent effect on protein synthesis.
Показать больше [+] Меньше [-]An estimation of sulfur concentrations released by three algae (Chlorella vulgaris, Chlamydomonas reinhardtii, Scenedesmus obliquus) in response to variable growth photoperiods Полный текст
2020
Mangal, Vaughn | Phung, Ta | Guéguen, Céline
In this study, we estimated extracellular concentrations of algal-derived sulfur species in response to changing photoperiods. Cultures from three algal species (Chlorella vulgaris, Chlamydomonas reinhardtii, Scenedesmus obliquus) were subjected to five different light:dark cycles (12:12, 14:10, 16:8, 18:6, 20:4 h) for a period of 3 days. Sulfur compounds including total reactive thiol concentrations, electroactive reduced sulfur species (RSS), and thiol isomers were measured using qBBr fluorescence, differential pulse cathodic stripping voltammetry (DP-CSV), and high-resolution mass spectrometry (HRMS), respectively. Total reactive thiol concentrations were greater in Scenedesmus than in Chlamydomonas and Chlorella at low light regimes (i.e., 12:12 h) whereas Chlamydomonas produced more RSS than the other two species (p < 0.05) at any light regime. Scenedesmus was the only responsive species to produce maximal electroactive RSS, and HRMS equivalent thiol compounds under low light regime, congruent with previous studies. Principal component analysis revealed relationships between qBBr-equivalent thiol and GSH-equivalent RSS concentrations for Scenedesmus and Chlamydomonas (p < 0.05) suggesting that thiols were the dominant species in the pool of electroactive RSS for these two algal species. Overall, these results showed that the light growth conditions greatly influenced the production of S-rich compounds by algae, affecting the complexation of metals such as mercury and cadmium, especially during planktonic blooms.
Показать больше [+] Меньше [-]Greenhouse gas emissions from advanced oxidation processes in the degradation of bisphenol A: a comparative study of the H2O2/UV, TiO2 /UV, and ozonation processes Полный текст
2020
Kang, Young-Min | Kim, Tae-Kyoung | Kim, Moon-Kyung | Zoh, Kyung-Duk
To estimate greenhouse gas (GHG) emissions and degradation rate constants (kₒbₛ) from H₂O₂/UV-C, TiO₂/UV-C, and ozonation processes in the degradation of bisphenol A (BPA), the laboratory scale experiments were conducted. In the H₂O₂/UV-C process, the fastest degradation rate constant (kₒbₛ = 0.353 min⁻¹) was observed at 4 mM of H₂O₂, while the minimum GHG emission was achieved at 3 mM of H₂O₂. In the TiO₂/UV-C process, the fastest rate constant (kₒbₛ = 0.126 min⁻¹) was achieved at 2000 mg/L of TiO₂, while the minimum GHG emission was observed at 400 mg/L of TiO₂. In the ozonation process, GHG emissions were minimal at 5 mg/L of O₃, but the degradation rate constant kept on increasing as the O₃ concentration increased. There were three major types of GHG emissions in the advanced oxidation processes (AOPs). In the ozonation process, most of the GHG emissions were generated by electricity consumption. TiO₂/UV-C process accounted for a significant portion of the GHGs generated by the use of chemicals. Finally, the H₂O₂/UV-C process produced similar GHG emissions from both chemical inputs and electricity consumption. The carbon footprint calculation revealed that for the treatment of 1 m³ of water contaminated with 0.04 mM BPA, the H₂O₂/UV-C process had the smallest carbon footprint (0.565 kg CO₂ eq/m³), followed by the TiO₂/UV-C process (3.445 kg CO₂ eq/m³) and the ozonation process (3.897 kg CO₂ eq/m³). Our results imply that the increase in removal rate constant might not be the optimal parameter for reducing GHG emissions during the application of these processes. Graphical abstract .
Показать больше [+] Меньше [-]Enhanced Cr(VI) removal by waste biomass derived nitrogen/oxygen co-doped microporous biocarbon Полный текст
2020
Li, Panyu | Hu, Mengning | Suo, Jiao | Xie, Yi | Hu, Wanrong | Wang, Xuqian | Wang, Yabo | Zhang, Yongkui
Herein, kitchen waste hydrolysis residue (KWHR) was utilized as the precursor to fabricate nitrogen/oxygen co-doped microporous biocarbons (NOMBs) with ultrahigh specific surface area via KOH activation. Activation temperature was found to be crucial for heteroatom doping and pore structure construction. Attractively, the obtained NOMB with high surface area (2417 m²/g) and microporosity (~ 90%) displayed an outstanding capacity of Cr(VI) removal (526.1 mg/g at pH 2). The kinetics and isotherm studies showed that the adsorption of Cr(VI) onto NOMB was well described by the pseudo-second-order kinetics and Langmuir isotherm. Moreover, it was found that Cr(VI) was partly reduced to Cr(III) during the removal process as the nitrogen/oxygen functionalities and unsaturated carbon bond played crucial roles of electron-donors, which revealed the fact that the removal of Cr(VI) by NOMB was attributed to the coupling of adsorption and reduction reaction. Overall, this study has demonstrated the possibility of preparing microporous biocarbons using KWHR as a renewable material and the resultant NOMB is of great potential to detoxify Cr(VI).
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