细化搜索
结果 3611-3620 的 6,560
The effects of field-realistic doses of imidacloprid on Melipona quadrifasciata (Apidae: Meliponini) workers 全文
2020
Brito, Pedro | Elias, Marcos | Silva-Neto, Carlos | Sujii, Edison | Silva, Daniela | Gonçalves, Bruno | Franceschinelli, Edivani
The presence of Brazilian native bees can improve tomato production by increasing pollination effectiveness. However, the extensive use of pesticides in tomato cultures may be harmful to bees. Imidacloprid-based insecticides are used in tomato plantations because of its high efficiency against tomato pests. This study investigated the effects of oral intake of field-realistic concentrations of imidacloprid by M. quadrifasciata workers, a stingless native bee from Brazil and effective pollinators of tomato crops. The oral intake of sucrose syrup added with 10, 35, or 70 ppb of imidacloprid did not increase the mortality rate when compared with the control group. However, we observed a reduction in the workers’ motility and food consumption. We also treated M. quadrifasciata workers with sucrose syrup mixed with an imidacloprid-based insecticide (Evidence 700 WG®, Bayer), with the final concentration of 250 ppb of imidacloprid. This treatment did not cause visible alterations of the intestine absorptive cells of the bees’ midgut and did not increase DNA damage. Therefore, the observed reduction of food consumption and locomotion behavior of M. quadrifasciata workers may contribute to the global effort to understand the contribution of neonicotinoids on bees’ population decline process.
显示更多 [+] 显示较少 [-]Analysis of the interannual variation characteristics of the northernmost drift position of the green tide in the Yellow Sea 全文
2020
Li, Dongxue | Gao, Zhiqiang | Zheng, Xiangyang | Wang, Nanyu
The green tide in the Yellow Sea is the world’s largest macroalgal bloom. The maximum area affected by green tide can reach tens of thousands of square kilometers. Previous studies have shown that green tide drifts northward during the outbreak, yet the location of its northernmost drift and the characteristics of interannual variations have not been explored in detail. In this paper, we use the Moderate Resolution Imaging Spectrometer (MODIS) data, GaoFen-1 (GF-1) satellite data, unmanned aerial vehicle (UAV) aerial data, and field trips for extraction and monitoring of green tide and then analyze the emergence, development, and dissipation of the green tide in Rongcheng coastal waters and the change of the northernmost drift position and its related factors from the year of 2013 to 2018. The results show that green tide have drifted to the Rongcheng coastal area over the years and the northernmost drift position can reach 37.662° N in 2014. Interannual difference of the northernmost position of the drift of the green tide is obvious, it is mainly affected by the wind, and there is no certain connection with the maximum coverage area, the coverage area when reaching the northernmost position, and the existence days of the green tide. These results can help to understand the drift range and dissipation process of green tide in the Yellow Sea.
显示更多 [+] 显示较少 [-]Fog, Temperature and Air Quality Over the Metropolitan Area of São Paulo: a Trend Analysis from 1998 to 2018 全文
2020
Mühlig, André Cardoso | Klemm, Otto | Gonçalves, Fábio Luiz Teixeira
This study investigates the long-term development of fog occurrences in the Metropolitan Area of São Paulo (MASP). Specifically, it analyzes the roles of meteorological and air quality parameters as potential drivers for fog formation. A dataset reaching back to the year 1933 shows that the overall trends of the annual fog occurrences (AFO) coincide with those of the annual mean temperature. Air quality data have been available since 1998, allowing us to perform a statistical analysis of the contributions of meteorology and air quality to AFO for the period from 1998 to 2018. The logistic regression model shows that the binary dependent variable (daily fog occurrence, FO) is explained by its independent predictors PM₁₀, relative humidity (rH), and daily minimum temperature (Tₘᵢₙ), in that order. FO was not found to be significantly influenced by atmospheric pressure (aP) and nitrogen oxides (NOₓ). While the influence of SO₂ was minor and associated with less confidence, it was negative. Potential causes for these surprising results are discussed. We conclude that the parameters PM₁₀, rH, and Tₘᵢₙ are significant drivers of fog formation in the MASP, whereby the total explanatory power of the drivers for the dichotomous variable FO is 16%.
显示更多 [+] 显示较少 [-]Levels and distribution pattern of organochlorine pesticide residues in eggs of 22 terrestrial birds from Tamil Nadu, India 全文
2020
Venugopal, Dhananjayan | Subramanian, Muralidharan | Rajamani, Jayakumar | Palaniyappan, Jayanthi | Samidurai, Jayakumar | Arumugam, Alaguraj
Long-term monitoring is essential to assess the patterns and distribution of the residues of organochlorine pesticides (OCPs) in biota. Bird eggs have several advantages than other environmental matrixes, which have been used extensively to portray the accumulation and distribution of OCPs. The present study investigated the organochlorine pesticide (OCP) residues in eggs of 22 species of terrestrial birds collected from Tamil Nadu, India. Eggs found abandoned were collected during nest monitoring between 2001 and 2008 and analyzed for the presence of organochlorine pesticide residues. The results showed that the mean concentrations of total hexachlorohexane (∑HCHs), total dichlorodiphenyltrichloroethane (∑DDTs), heptachlor epoxide, and dieldrin ranged from non-detectable (nd) to 2800 ng/g, nd to1000 ng/g, nd to 700 ng/g, and nd to 240 ng/g on a wet mass (wm) basis, respectively. The variation in magnitude of contamination among the species and feeding guilds were not significantly different (p > 0.05). Among the OCPs analyzed, the residues of β-HCH and p,p′-DDE were found to be the abundant in concentration. Similarly, among various bird species studied, the highest concentrations of ∑OCPs (> 5000 ng/g wm) were recorded in the eggs of gray junglefowl, scaly-breasted munia, and red-whiskered bulbul. This may be due to their widespread occurrence of their habitat at proximity to the agricultural fields, where organochlorines were in use until recently. Among the various contaminants analyzed, concentrations of p,p′-DDE and heptachlor epoxide exceeded the threshold levels of toxicity for wild birds in > 5% of the egg samples. Hence, this study indicates the need for continued monitoring and further systematic ecotoxicological investigation of these compounds not only in eggs but also in other environmental media.
显示更多 [+] 显示较少 [-]Whether the carbon emission from green roofs can be effectively mitigated by recycling waste building material as green roof substrate during five-year operation? 全文
2020
Fan, Liangqian | Wang, Jingting | Liu, Xiaoling | Luo, Hongbing | Zhang, Ke | Fu, Xiaoying | Li, Mei | Li, Xiaoting | Jiang, Bing | Chen, Jia | Fu, Shuzhi | Mo, You | Li, Lin | Chen, Wei | Cheng, Lin | Chen, Fenghui | Ji, Lin | Ma, Dandan | Zhang, Xiaohong | Anderson, Bruce C.
Green roof (GF) as an important role of urban ecosystem services is more and more focused on carbon sequestration for the mitigation of climate change, which there is still a gap of longer period of investigation on carbon sequestration on GF. This work aims to quantify the carbon sequestration on green roofs from 2012 to 2017 by measuring and calculating parameter on substrate organic carbon and plant organic carbon, when using waste building material substrate (WBMS) as GF substrate for the recycling of waste solid. Green roof group 2 (waste building material substrate (WBMS) as substrate) and green roof group 1 (local natural soil (LNS) as substrate), planting same three native plants (N. auriculata, L. spicata, and L. vicaryi), were both three substrate depth of 20 cm, 25 cm, and 30 cm, respectively. Results show that both innovative WBMS and LNS were a great capability of carbon sequestration and carbon storage on green roofs. Carbon storage of green roof group 1 and green roof group 2 was 65.6 kg C m⁻² and 72.6 kg C m⁻², respectively. Annual mean carbon sequestration of the WBMS was 1.8 times higher than LNS. The overall average carbon sequestration (12.8 kg C m⁻² year⁻¹) in green roof group 2 using WBMS was 1.1 times than corresponding in green roof group 1 (11.4 kg C m⁻² year⁻¹ using LNS). WBMS substrate and L. vicaryi could be considered as the most adaptable green roof configuration, which can be a recommendation to promote the carbon sequestration and the function of green roof for the better urban ecosystem services. Future work may focus on the GF carbon model, water interface, long-term monitoring, environmental impact, water quality and quantity, synthesized effect on GF ecosystem, low impact development (LID), management and simulation, and combination on intelligent urban system, based on LCA.
显示更多 [+] 显示较少 [-]The nexus between tourism, economic growth, renewable energy consumption, and carbon dioxide emissions: contemporary evidence from OECD countries 全文
2020
Dogru, Tarik | Bulut, Umit | Kocak, Emrah | Isik, Cem | Suess, Courtney | Sirakaya-Turk, Ercan
The relationship between tourism development, economic growth, renewable energy consumption, and carbon dioxide emissions has been examined in a variety of contexts; however, the extant studies report contradictory findings mainly due to utilizing arbitrary empirical techniques. We present a comprehensive literature review and the effects of tourism development, economic growth, and renewable energy consumption on the carbon dioxide (CO₂) emission. Specifically, the effects of gross domestic product, renewable energy consumption, and tourism receipts on carbon dioxide emissions in OECD countries are examined utilizing the bootstrap panel cointegration technique and the augmented mean group estimator. The results showed that tourism development has negative and significant effects on CO₂ emission in Canada, Czechia, and Turkey, while tourism development has positive and significant effects on CO₂ emission in Italy, Luxembourg, and the Slovak Republic. Also, Belgium, France, New Zealand, and the Slovak Republic have shifted towards sustainable tourism practices. Theoretical and practical implications are discussed.
显示更多 [+] 显示较少 [-]Removal of nitrate nitrogen from water by phosphotungstate-supported TiO2 photocatalytic method 全文
2020
Ge, Xiaohong | Fu, Weizhang | Wang, Yujun | Wang, Lingsheng | Yao, Fanfeng
Nitrate nitrogen in water, especially in groundwater, is a major problem in the current drinking water environment. In this study, copper- and nickel-modified phosphotungstate catalysts supported on TiO₂ were prepared by the sol-gel solvothermal method, and photocatalytic reduction by phosphotungstate was used to remove nitrate nitrogen in water under ultraviolet irradiation. The maximum removal rate was 59.60% with 0.8 g/L Cu-H₃PW₁₂O₄₀/TiO₂, 90 mg/L nitrate nitrogen, and 60 min reaction time. For Ni-H₃PW₁₂O₄₀/TiO₂, the maximum removal rate of nitrate nitrogen was 54.58%, achieved with a catalyst concentration of 0.8 g/L, nitrate nitrogen concentration of 120 mg/L, and reaction time of 30 min. Both catalysts could remove nitrate nitrogen from water under the condition of photocatalysis.
显示更多 [+] 显示较少 [-]Response Surface Methodology as an Optimization Tool for Anaerobic Digestion of Food Waste 全文
2020
Parra-Orobio, Brayan Alexis | Torres-López, Wilmar Alexander | Torres-Lozada, Patricia
Biowastes are the main fraction of municipal solid waste (MSW), and of this, food waste (FW) is the predominant component. Given that FW is predominantly biodegradable organic matter, approach strategies such as anaerobic digestion (AD) are suitable to apply on these substrates because these process also produces methane gas as a renewable energy source, particularly important given the depletion of nonrenewable energy sources. This study evaluated the influence of two parameters on AD: substrate-inoculum ratio (S/I: 0.5 to 2.0 gVSₛᵤbₛₜᵣₐₜₑ gVSᵢₙₒcᵤₗᵤₘ⁻¹) and pH (7.0 to 8.0 units) on biochemical methane potential (BMP) using the response surface methodology (RSM), a valuable tool which can be used to establish strategies that allow for the control and optimization of the AD of FW. Of the conditions evaluated, it was found that the optimal S/I ratio and pH conditions to guarantee the highest BMP (297.05 ± 14.38 mL CH₄ gVS⁻¹) were S/I ratio = 0.19 gVSₛᵤbₛₜᵣₐₜₑ gVSᵢₙₒcᵤₗᵤₘ⁻¹ and pH = 7.5. Although the hydrolysis constant (kₕ) was low, in all conditions, it was in the range reported for substrates with a high carbohydrate content, such as FW (0.002–0.25 day⁻¹). In this study, pH was found to be the factor that had the most significant effect on kₕ and BMP.
显示更多 [+] 显示较少 [-]A Miniaturized Gas-Liquid Separator for Use in Liquid-Phase Microextraction Procedures: Determination of Mercury in Food 全文
2020
Menezes, Rebeca Moraes | Santos, Walter Nei Lopes | Silva, Uneliton Neves | Lemos, Valfredo Azevedo
A method for the preconcentration of mercury using vortex-assisted temperature-controlled dispersive liquid-phase microextraction (VA-TC-DLPME) is proposed. A miniaturized gas-liquid separator (m-GLS) was developed and applied to the determination of mercury after VA-TC-DLPME. The detection was performed using cold vapor atomic absorption spectrometry (CV AAS). Ammonium pyrrolidine dithiocarbamate (APDC) reagent was used as a complexing agent for Hg(II). The VA-TC-DLPME method consists in dispersing the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim][PF₆]) in the aqueous phase by vigorous vortexing, followed by heating and cooling in an ice bath. The mixture was submitted to centrifugation, and the sedimented rich phase was then dissolved in an acid solution to reduce viscosity. Mercury was quantified in the final solution using m-GLS and CV AAS. Under optimized conditions, the method presents a limit of detection of 4.5 × 10⁻² μg L⁻¹, and an enrichment factor of 54. The accuracy was evaluated by the determination of mercury in reference material-certified ERM-CE 278, mussel tissue. The method was applied to the determination of mercury in fish oil samples. The developed m-GLS can be tested for use after other LPME procedures.
显示更多 [+] 显示较少 [-]Effects of Polyethylene Microplastics on Freshwater Oligochaeta Allonais inaequalis (Stephenson, 1911) Under Conventional and Stressful Exposures 全文
2020
Castro, Gleyson B. | Bernegossi, Aline C. | Pinheiro, Fernanda R. | Felipe, Mayara C. | Corbi, Juliano J.
The occurrence of microplastics in the aquatic environment has been reported around the world; however, their effects on freshwater oligochaetes are unknown. In this research, we investigated the toxic effects of polyethylene microplastics (MP), size between 40 and 48 μm, on the aquatic worm Allonais inaequalis. We applied the bioassays considering 24 °C as standard temperature and thermal stress of 19 °C and 29 °C, associated with the presence and absence of sediment in short-term and chronic exposures (96 h and 240 h, respectively). MP did not cause significant mortality in short-term exposures and did not affect the reproduction of worms. In addition, when we analyzed whether thermal stress, as well as substrate availability, would have an additional impact on MP toxicity, there were no significant effects. At 29 °C, the individuals reached the highest reproduction rates, whereas at 19 °C the offspring significantly reduced. Moreover, the lack of sediment substantially reduced survival rates after 96 h under 24 °C (p = 0.018). This paper also records for the first time, the ability of microplastic ingestion by a freshwater naidid. Due to its capacity to respond in a short period, adaptation to laboratory cultivation, and representativeness among freshwater aquatic invertebrates, A. inaequalis is presented as a tropical test organism for toxic effect analysis of microplastics, either in conventional exposures or simulated environmental disturbances.
显示更多 [+] 显示较少 [-]