Modelling nitrous and nitric oxide emissions by autotrophic ammonia-oxidizing bacteria

The emission of greenhouse gases, such as N2O, from wastewater treatment plants is a matter of growing concern. Denitrification by ammonia-oxidizing bacteria (AOB) has been identified as the main N2O producing pathway. To estimate N2O emissions during biological nitrogen removal, reliable mathematical models are essential. In this work, a mathematical model for NO (a precursor for N2O formation) and N2O formation by AOB is presented. Based on mechanistic grounds, two possible reaction mechanisms for NO and N2O formation are distinguished, which differ in the origin of the reducing equivalents needed for denitrification by AOB. These two scenarios have been compared in a simulation study, assessing the influence of the aeration/stripping rate and the resulting dissolved oxygen (DO) concentration on the NO and N2O emission from a SHARON partial nitritation reactor. The study of the simulated model behavior and its comparison with previously published experimental data serves in elucidating the true NO and N2O formation mechanism

Media Multitasking: A Bibliometric Approach and Literature Review

Media multitasking became increasingly popular over the past decade. As this behavior is intensely taxing cognitive resources, it has raised interest and concerns among academics in a variety of fields. Consequently, in recent years, research on how, when, and why people media multitask has strongly emerged, and the consequences of the behavior for a great variety of outcomes (such as working memory, task performance, or socioemotional outcomes) have been explored. While efforts are made to summarize the findings of media multitasking research until date, these meta, and literature studies focused on specific research subdomains. Therefore, the current study adopted a quantitative method to map all studies in the broad field of media multitasking research. The bibliometric and thematic content analyses helped us identifying five major research topics and trends in the overall media multitasking domain. While media multitasking research started by studying its prevalence, appearance, and predictors, early research within the domain was also interested in the impact of this media consumption behavior on individuals' cognitive control and academic performance. Later on in 2007, scholars investigated the implications of media multitasking on the processing of media- and persuasive content, while its impact on socioemotional well-being received attention ever since 2009. Our analyses indicate that research within the field of media multitasking knows a dominant focus on adolescents, television watching, and cognitive depletion. Based on these findings, the paper concludes by discussing directions for future research

Fundamental movement skills in grassroots soccer:A comparative study of coaches’ perceptions and practices in 9 European countries

Fundamental Movement Skills (FMS) are proven to be beneficial for development across sports domains, including soccer. Grassroots soccer provides a substantial platform to promote and develop FMS. However, coaches often have limited knowledge about FMS. Therefore, this study aimed to explore the perceptions and practices of FMS among grassroots soccer coaches across nine European countries and various coaching profiles. This study surveyed 1055 grassroots coaches from 9 countries based on prior studies to understand their perceptions and practices regarding FMS. Firstly, 14 questions were divided into three components with a Principal Component Analysis to enable clearer analysis: ‘Coaching Effectiveness,’ ‘Influencing Factors,’ and ‘Importance of FMS.’ The second phase involved comparing countries and coaching profiles to see how perceptions and practices varied by coaches’ expertise, experience, and the age group they coach. Kruskal-Wallis group comparisons revealed varied awareness and understanding of FMS among grassroots coaches in nine European countries (p &lt; 0.001). Post-hoc results showed that perceptions and practices were influenced more by coaching experience (p &lt; 0.01) and the age group coached (p &lt; 0.01) rather than qualifications. Coaches with over 10 years of experience and those working in the fundamental phase (U7-U12) recognized the benefits of FMS to a greater extent. While FMS awareness exists, deep understanding and practical implementation remain challenging. Differences between countries suggest a unified approach to FMS in coach education is missing. Strengthening FMS education will ensure that grassroots coaches are better equipped to develop young players, ultimately contributing to more effective long-term player development.</p

Water resource recovery by means of microalgae cultivation in outdoor photobioreactors using the effluent from an anaerobic membrane bioreactor fed with pre-treated sewage

[EN] With the aim of assessing the potential of microalgae cultivation for water resource recovery (WRR), the performance of three 0.55 m3 flat-plate photobioreactors (PBRs) was evaluated in terms of nutrient removal rate (NRR) and biomass production. The PBRs were operated outdoor (at ambient temperature and light intensity) using as growth media the nutrient-rich effluent from an AnMBR fed with pre-treated sewage. Solar irradiance was the most determining factor affecting NRR. Biomass productivity was significantly affected by temperatures below 20 °C. The maximum biomass productivity (52.3 mg VSS·L&#8722;1·d&#8722;1) and NRR (5.84 mg NH4-N·L&#8722;1·d&#8722;1 and 0.85 mg PO4-P·L&#8722;1·d&#8722;1) were achieved at solar irradiance of 395 &#956;E·m&#8722;2·s&#8722;1, temperature of 25.5 °C, and HRT of 8 days. Under these conditions, it was possible to comply with effluent nutrient standards (European Directive 91/271/CEE) when the nutrient content in the influent was in the range of 40 50 mg N·L&#8722;1 and 6 7 mg P·L&#8722;1.This research work was possible thanks to project CTM2011-28595-C02-01/02 funded by the Spanish Ministry of Economy and Competitiveness jointly with the European Regional Development Fund and Generalitat Valenciana (GVA-ACOMP2013/203). This research was also supported by the Spanish Ministry of Science and Innovation via a pre-doctoral FPU fellowship to the second author (AP2010-3708).Viruela Navarro, A.; Murgui Mezquita, M.; Gómez Gil, TA.; Durán Pinzón, F.; Robles Martínez, Á.; Ruano García, MV.; Ferrer Polo, J.... (2016). Water resource recovery by means of microalgae cultivation in outdoor photobioreactors using the effluent from an anaerobic membrane bioreactor fed with pre-treated sewage. Bioresource Technology. 218:447-454. https://doi.org/10.1016/j.biortech.2016.06.116S44745421

Fundamental movement skills in grassroots soccer : A comparative study of coaches’ perceptions and practices in 9 European countries

Fundamental Movement Skills (FMS) are proven to be beneficial for development across sports domains, including soccer. Grassroots soccer provides a substantial platform to promote and develop FMS. However, coaches often have limited knowledge about FMS. Therefore, this study aimed to explore the perceptions and practices of FMS among grassroots soccer coaches across nine European countries and various coaching profiles. This study surveyed 1055 grassroots coaches from 9 countries based on prior studies to understand their perceptions and practices regarding FMS. Firstly, 14 questions were divided into three components with a Principal Component Analysis to enable clearer analysis: ‘Coaching Effectiveness,’ ‘Influencing Factors,’ and ‘Importance of FMS.’ The second phase involved comparing countries and coaching profiles to see how perceptions and practices varied by coaches’ expertise, experience, and the age group they coach. Kruskal-Wallis group comparisons revealed varied awareness and understanding of FMS among grassroots coaches in nine European countries (p < 0.001). Post-hoc results showed that perceptions and practices were influenced more by coaching experience (p < 0.01) and the age group coached (p < 0.01) rather than qualifications. Coaches with over 10 years of experience and those working in the fundamental phase (U7-U12) recognized the benefits of FMS to a greater extent. While FMS awareness exists, deep understanding and practical implementation remain challenging. Differences between countries suggest a unified approach to FMS in coach education is missing. Strengthening FMS education will ensure that grassroots coaches are better equipped to develop young players, ultimately contributing to more effective long-term player development

The determinants of conversion rates in SME e-commerce websites

© 2017 Web retailers invest significant resources to improve the proportion of website visitors that make a purchase, also known as the conversion rate. Improving this rate is particularly important to SMEs that have traditionally lagged behind larger firms as they have found it difficult to justify the significant investment involved in website development against the historical low returns associated with an online sales channel. Identifying methods that increase conversion rates reduces these perceived barriers and increases effective SME participation in the growing e-commerce sector. This paper uses 1184 observations from 6 SME websites to identify and analyse the factors, or combination of factors, that improve conversion rates. This is achieved through a process of exploratory regression analysis to select the most relevant determinants and Qualitative Comparative Analysis (QCA) to offer more ‘fine-grained’ detail on the conditions where conversion rates improve. Our findings suggest that a key factor that improves the conversion rate is a strategy that focuses upon either quality or promotion and avoids mixing such attributes within the web site offer

Rethinking Our Habits: Development and Effects of Interventions to Promote Mindful Sharenting

This chapter enhances our understanding of the influencer sharenting phenomenon by consolidating insights previously explored in the book. It delves deeper into the influence of contextual factors and cognitive biases, illustrating how these elements contribute to influencer parents' tendency to underestimate the risks associated with sharenting. This chapter also delineates the ecosystem in which influencer parents operate and the various factors that contribute to their inclination to prioritise short-term gains over the long-term downsides associated with sharenting behaviour. We examine existing interventions aimed at sensitising and supporting (influencer) parents regarding their sharenting behaviours and discuss the effectiveness of a Flemish intervention with a central focus on influencer sharenting. To conclude, the chapter offers inspiration for future interventions, underscoring the importance of considering diverse stakeholders beyond parents. We provide insights into the complexities of altering (influencer) sharenting behaviour and the challenges and opportunities for promoting online safety and long-term well-being of children. This comprehensive approach seeks to inform future research and intervention efforts, focusing on fostering collaborative and holistic strategies to address the evolving landscape of influencer sharenting in the digital age

Removal and reuse of phosphorus from wastewater using microalgae

Phosphorus (P) is an essential element to sustain the global food and feed production. Large amounts of phosphate ores are extracted for the production of fertilizers. The recent global P crisis increased the awareness to use this natural resource in a sustainable way and to increase recycling. A significant part of the global annual P flux ends up in wastewater. Wastewaters are often treated using energy or chemical intensive technologies to decrease the P load and thus prevent eutrophication of receiving surface waters. The recycling of P removed from wastewaters using these technologies is limited. The application of new strategies to recover and reuse P is necessary. Microalgae based wastewater treatment systems hold the potential to remove and reuse the P, by integrating P into a biomass that can be valorised. Microalgae have been used for wastewater treatment since the 1960s, however the P recovery needs to be optimised. The wastewaters are often nitrogen (N) and not P-limited, thereby leaving large quantities of residual P in the water. The goal of this thesis was to evaluate the P recovery from wastewaters with a variable N:P ratio using microalgae. The flexibility of the microalgal P composition is determined under variable N and P supply and is compared among different microalgae species. The bioavailability of the wastewater dissolved P fraction is measured in bioassays. Indirect P removal, by microalgae mediated P precipitation, is studied and the resulting flocculation to harvest the cells is investigated. The P uptake by microalgae under variable N and P supply was investigated in synthetic wastewaters to determine the influence of one nutrient on the removal of the other nutrient. Both Chlorella and Scenedesmus adjusted their biomass N and P content to the variable nutrient supply, while the influence on algal biomass produced was small. Chlorella had a higher biomass N content than Scenedesmus while the reverse was true for P. The concentrations of P in the biomass remained low and were relatively constant (0.6 – 0.8 % P) when the N supply and N concentration in the biomass was low. In contrast, at high initial N supply, the biomass P concentrations were more variable and increased to 1.7% P at high P supply. The underlying physiological mechanism may be related to the protein and rRNA content of the biomass. At higher N supply the protein synthesis increases and thus the rRNA synthesis may also be increased. As rRNA is a large constituent of the biomass P, this may explain the increased P accumulation under high N supply. Cyanobacteria are much less studied in the context of wastewater treatment compared to eukaryotic microalgae but have several potential advantages. A Pseudanabaena species was isolated from an eutrophic reservoir and had a growth rate similar to Chlorella grown under the same conditions. Under high N supply, this Pseudanabaena species has a high N content (up to 14%) due to the accumulation of protein (77%). The biomass N concentration is high compared to Chlorella (10%) and Scenedesmus (8%) grown under similar conditions. Under low N supply, up to 77% of carbohydrates were accumulated in the biomass. The biochemical biomass composition of this species is highly flexible and therefore this Pseudanabaena species is suitable for the production of animal feed (high protein content) or bio-energy (high carbohydrate content) by fine-tuning the N supply. The P removal potential of Chlorella, Scenedesmus and Pseudanabaena was compared. The fraction of P removed from all synthetic wastewaters was above 80% when the initial N:P ratio in water exceeded 20. In contrast, the P removal decreased when the N:P ratio was decreasing below 20. Wastewaters often have these low N:P ratios indicating that P removal by microalgae may be hampered. In such waters, removal of P was typically highest for Scenedemus and lowest for Chlorella because Scenedesmus can accumulate P to the largest extent. The effective microalgal removal of P from real wastewaters requires that the P forms in wastewater are readily available for algal uptake. Wastewaters contain a mixture of different chemical P forms including inorganic and organic P, both in the dissolved and particulate phase. The bioavailability of these P forms (BAP) in wastewater may be variable and therefore the BAP of the dissolved P fraction of different raw wastewaters was evaluated. The bioassays were performed using Chlorella vulgaris, as a model species for wastewater treatment and used P-limiting conditions. Overall the BAP of the wastewater dissolved P fraction was high (> 70%). This corresponded with the high orthophosphate fraction measured in these wastewaters. Additionally the chemical fractionation showed that part of the colloidal P (e.g. humic-metal-phosphate) and organic P (e.g. phosphate esters) was also bioavailable, because the time for uptake under P-limited conditions was sufficiently large for effective use of the less available P species. Microalgae can remove P from wastewater by direct uptake or indirectly by inducing precipitation of P. During microalgal growth, CO2 is taken up as HCO3- , thereby increasing the solution pH. As a consequence Ca-phosphates can more readily precipitate and the formed precipitate can induce flocculation of the microalgal cells due to charge neutralisation of the cell surface. This is attractive since low-cost harvesting of microalgae is a major challenge. In jar test experiments, flocculation by Ca-phosphate precipitation was induced at relatively low pH when calcium and P concentrations are sufficiently high. In real systems, however, this flocculation often fails probably due to the presence of inhibitory substances. The inhibition of flocculation in the presence of organic matter, including algal organic matter and model organic compounds, was evaluated. Addition of dissolved organic compounds showed that organic acids with a high molecular weight (e.g. humic acids, alginate) have a strong inhibitory effect on flocculation whereas glucose or acetate had no such effect. The inhibitory effects may be related to complexation of Ca2+ or effects of organic matter on growth of the Ca-phosphate crystals. Precipitation of Ca-phosphate in media with high organic matter content requires a high water hardness (> 0.50 mM Ca) and high PO4 concentrations (> 0.35 mM P). Taking these requirements into account, flocculation by Ca-phosphate precipitation is a promising cost-efficient harvesting technique which can remove surplus P from wastewater.status: publishe