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We explore several methodological challenges that continue to hinder progress in quantifying global volcanic Hg emissions, and discuss the importance of longer time-frame data collection to capture temporal variations in emissions. Recommendations are proposed for working toward a more accurate assessment of the global volcanic Hg flux. A detailed summary of all published volcanic Hg emissions data worldwide is also presented as a reference tool for future work.Carbon deposition usually hinders catalytic activity in one catalysis. In this work, carbon-deposition influence was investigated on selective catalytic reduction (SCR) of nitric oxide (NO) by a theoretical-experimental method. Density-functional-theory calculations showed that carbon deposition increased adsorption energy of NO on oxide. For example, adsorption energy on Fe2O3 increased from 1.70 to 5.27 eV. Carbon deposition increased activity by following processes NO adsorption, NO dissociation, oxygen transmittance, CO-group formation, and N2/CO2 evolutions. Among these stages, CO-group formation was a key step. Based on these computational predictions, an experimental SCR was carried out for the verification. As a result, a carbon-deposited catalyst had a better SCR activity (20% higher) than the corresponding oxide catalyst. Characterizations showed that carbon deposition increased the amounts of medium/strong acidic sites as well as the reducibility of the catalytic center. The main result of this article helps to understand the interface behavior of carbon on a catalyst during SCR. Above results are also in favor of designing a more effective SCR reactor to ensure a more stable running.Coastal aquaculture expansion resulted in mangrove area loss and ecosystem degradation in the past decades, mainly in tropical Asia. Despite increasing environmental concerns regarding nutrient and organic matter-rich effluents, little is known on the effects on adjacent estuarine and coastal food webs. To assess the impact and fate of anthropogenic nitrogen released from aquaculture facilities, we studied water quality and nitrogen (N) flow across an estuarine food web in an estuary in Hainan, China, using nitrogen stable isotopes (δ15N). We found higher δ15N values of ammonium, nitrate and suspended matter in the pond-covered inner estuary than further upstream, suggesting a strong influence of untreated pond effluents, which had a high δ15N (ammonium ~16‰, nitrate ~7‰, suspended matter ~8‰). Fish and benthic invertebrates of the inner estuary had a higher δ15N than consumers further upstream and in similar aquaculture-free estuaries elsewhere, most likely due to direct or indirect uptake of 15N-enriched aquaculture effluents by phytoplankton and benthic algae. A major part of the artisanal catches from the estuary consists of small-size fish which is used as feed in the local aquaculture. Thus, estuarine fish incorporating aquaculture-effluent based food web signals are harvested and recycled as feed in aquaculture facilities, whose effluents sustain this local food web. The δ15N being at the high end of the global range on all trophic levels indicates an anthropogenic nitrogen loop in which some portion of the reactive nitrogen initially introduced into aquaculture ponds is continuously recycled and affects the estuarine food web. This recycling also indicates a shortcut in the otherwise inefficient nitrogen sink function of estuaries. Therefore, in areas with large-scale coastal aquaculture like in China and SE Asia the effect of reactive nitrogen from aquaculture sources on the performance of coastal ecosystems may be larger than previously thought.The Ecosystem services (ESs), which play an important role in the balance of the natural ecosystem and social-economic development, are suffering from degradation caused by human activities and climate change. However, the manner in which the ESs respond to the land use/cover changes (LUCCs) and the climatic factors respectively remain elusive, especially in the forest-steppe ecotone, which is highly sensitive to climate change and anthroponotic activities. Based on the remote sensing data and in situ meteorological data, we comprehensively modeled and compared 4 key ESs changes caused by 3 LUCC types, land-use change fraction, and climate changes through two simple comparative experiments. Angiotensin II human order Our results showed that the Grain for the Green Project improved the mean soil conservation, carbon sequestration, and water yield but reduced the sand fixation. The cropland expansion had a positive influence on the water yield and sand fixation, but it induced a decline in soil conservation and carbon sequestration. The urbanization very likely increased the water yield and decreased soil conservation, carbon sequestration, and sand fixation. The unequal change fractions of the same land-use conversion may affect the ESs differently. The ESs changes have different responses to climate change in different landscapes due to the ecological process. The water yield could be well explained by the temperature, precipitation, radiation, and wind speed. Climate change had a stronger effect on the water yield and carbon sequestration than the land use/cover changes but sand fixation and soil conservation were more likely to be affected by LUCCs. The impact of three types of land-use changes and climate change on the ecosystem services should be considered when formulating land-use policies. This paper might aid the decision-makers in achieving ESs sustainable management and develop land-use strategies in the forest-steppe ecotone.To reduce the harm to wildlife caused by habitat loss and degradation, significant resources have been invested in habitat restoration worldwide. However, whether restored habitats can support wildlife communities similar to those natural ones remains unclear. Providing habitat for waterbirds, which are dependent on wetland for their survival, is a major target in many wetland restoration practices. Here we conducted a year-round waterbird survey at Chongming Dongtan, a national nature reserve established for waterbird conservation in the south Yellow Sea, in order to compare the characteristics of waterbird communities in four wetland types restored wetlands, natural tidal wetlands, and two artificial wetlands (fish ponds and farmlands). We determined whether waterbird diversity and species composition differed among the wetland types. The results indicated that waterbird diversity, in terms of species richness, individual density, Shannon-Wiener diversity, functional diversity, and phylogenetic diversity, was generally similar in the restored and natural wetlands and was higher in the restored and natural wetlands than in fish ponds or farmlands. Most threatened species and exclusive species occurred in both natural and restored wetlands, but the overall species composition significantly differed between natural and restored wetlands. Non-metric multidimensional scaling analysis also indicated that waterbird community significantly differed among the wetland types. The results suggest that restored wetlands support substantial waterbird diversity but cannot replace natural wetlands because they lack the period tides that many tideland specialists (shorebirds) depend on. This study highlights the importance of protecting natural wetlands for waterbird conservation. We propose that both the diversity and species composition of wildlife communities should be considered in evaluating the effectiveness of habitat restoration for wildlife.In Sahelian landscapes, land use/land cover (LULC) dynamics and climate variability are already known to affect the water cycle. In its current practice however, hydrological modelling does not account for LULC changes. This issue pertains to rapidly evolving watersheds and might result in critical inaccuracies in the simulated processes. In this study, the Soil and Water Assessment Tool (SWAT) model was used to simulate surface runoff in the small Sahelian watershed of Tougou, which underwent significant LULC changes between 1952 and 2017. Based on rainfall/runoff data acquired from 2004 to 2018, the SWAT model was calibrated under two scenarios a static land use scenario (SLU) using a single LULC map (in 1999) and a dynamic land use scenario (DLU) integrating 3 LULC maps (1999, 2009 and 2017). The DLU scenario estimated with higher accuracy surface runoff, deep aquifer infiltration and actual evapotranspiration processes. Based on the calibrated parameters, surface runoff was simulated during the historical period 1952-2003 under four scenarios with static LULC maps (in 1952, 1973, 1986 and 1999) opposed to a fifth scenario integrating these LULC maps dynamically. The DLU scenario was found to be more effective at picturing the so-called Sahelian paradox (i.e. the increase in surface runoff despite the decrease in rainfall), reported in the literature for small watersheds in the Sahel. The analysis of variability revealed that fluctuations in surface runoff were both influenced by rainfall and LULC changes. Furthermore, the isolated contributions of climate variability and LULC changes on surface runoff showed that LULC conditions played a dominant role (ηlulc = +393.1%) in the runoff increase over climate (ηcl = -297%) during the historical period. These results highlight the importance of accounting for LULC dynamics in hydrological modelling and advocate the development of integrated modelling frameworks for hydrologists and water resource managers.
There is growing evidence in the scientific literature that individuals living near fields are more exposed to agricultural pesticides than people living further away.
The main objective of this systematic review was to identify the non-dietary determinants of pesticide exposure related to the drift pathway in residents living in agricultural areas, including spatial indictors related to agricultural activities, hygiene practices, behaviors and sociodemographic parameters.
Three databases were consulted (PubMed, Web of sciences, Scopus). At least two experts selected the eligible studies.
A total of 27 original studies (2002-2020) fulfilled the eligibility criteria of this review. These publications explored pesticide exposure of individuals through measurements in biological samples (n=13), environmental samples (n=11) or both (n=3). Spatial indicators, including residential proximity to fields, crop acreage around the residence and amounts of pesticides applied in the vicinity were identified as det to improve knowledge of the determinants of exposure.
This study consolidates our knowledge of the determinants influencing pesticide exposure levels in people living in agricultural areas. Nevertheless, the available scientific data is still too limited to serve as a basis for developing risk management measures. More research is needed to improve knowledge of the determinants of exposure.Constructing highly efficient metal-free material towards peroxymonosulfate (PMS) activation under photocatalytic assistance is a promising strategy for water decontamination. Herein, N vacancy modified g-C3N4 nanotube (VCN) was prepared to build a novel photo-assisted PMS activation system (PPAS), in which the unique electronic structure created by N vacancy could favor the PMS activation on VCN under visible-light irradiation. The role of N vacancy in PPAS was firstly studied through tuning its content in VCN. The results showed that the N vacancy greatly improved PMS activation on VCN PPAS towards organic pollutants removal. The VCN PPAS with moderate N vacancy modification performed best, whose kinetic constant for Rhodamine B degradation was 9.6 and 2.6 times higher than that of VCN/PMS system and pristine g-C3N4 PPAS, respectively. Moreover, the VCN PPAS performed well in wide pH range (3-12) and real water background. Selective removal of different organic pollutants was found on VCN PPAS, owing to the different interaction between pollutant and the catalyst surface with surface-bound radicals.
Here's my website: https://www.selleckchem.com/peptide/angiotensin-ii-human-acetate.html
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