922017 research outputs found
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Self-assembled 1T-MoS2/Functionalized Graphene Composite Electrodes for Supercapacitor Devices
No full textTwo-dimensional (2D) materials such as graphene and molybdenum disulfide (MoS2) have been investigated widely for applications in energy storage, including supercapacitors, due to their high specific surface area, potential redox activity and mechanical flexibility. However, electrodes comprised of either pure graphene and MoS2 have failed to reach their potential due to restacking of the layered structure and poor electrical conductivity. It has been shown previously that composite electrodes made from a mixture of graphene and MoS2 partially counteract these issues, however performance is still limited by poor mixing at the nanoscale. Herein, we form a true composite electrode by chemically functionalizing the graphene so that the negatively charged surface can self-assemble with the positively charged 1T-MoS2 to give an alternating layer structure. These alternately restacked 2D materials were then used to produce supercapacitor electrodes, and their energy storage properties characterized. This stacked structure has increased the interlayer spacing of 1T-MoS2 which was indicated by the increase of the intensity of the (001) peak in the XRD spectra. Furthermore, the typically metastable 1T-MoS2 was stabilized by the interaction with the functionalized graphene, preventing it reverting back to the 2H phase, which was observed when pristine graphene was used. The graphene was functionalized using either 4-bromobenzenediazonium (BBD) or 4-nitrobenzenediazonium (NBD), with the later giving optimal capacitance when mixed with the MoS2. The alternative layer graphene-MoS2 structure was confirmed by Raman spectroscopy and electron microscopy and lead to high specific capacitance (290 F cm-3 at 0.5 A g-1) and 90 % retention of capacitance after 10,000 cycles
Evaluation of two-year recall of self-reported pesticide exposure among Ugandan smallholder farmers
No full textObjectives: To evaluate smallholder farmers’ recall of pesticide use and exposure determinants over a two-year period in a low-income country context. Methods: The Pesticide Use in Tropical Settings (PESTROP) study in Uganda consists of 302 smallholder farmers who were interviewed in 2017. In the same season in 2019, these farmers were re-questioned concerning pesticide use (e.g., use of active ingredients) and exposure information (e.g., crops, personal protective equipment [PPE], hygienic behaviours) they had previously provided. The extent of recall bias was assessed by comparing responses at follow-up in 2019 with practices and behaviours reported from the baseline interview in 2017.Results: An 84% (n=255) follow-up response rate was attained. We found instances of better recall (e.g., overall agreement >70% and Area Under the Curve (AUC) values >0.7) for the use of some active ingredients, commonly used PPE items, and washing clothes after application, whereas only 13.3% could correctly recall their three major crops. We observed a trend where more individuals reported the use of active ingredients, while fewer reported the use of PPE items, two years later. In general, we found better agreement in the recall of years working with pesticides compared to hours per day or days per week in the field, with no apparent systematic over or under reporting by demographic characteristics. Conclusions: While some of these findings provide consistency with those from high-income countries, more research is needed on recall in poorly educated agriculture communities in low- and middle-income settings to confirm these results
Emotionally Based School Non-Attendance: Two Successful Returns to School Following Lockdown
No full textEmotionally based school non-attendance (EBSNA) needs are complex, with a distinctive combination of risk factors affecting each individual. This study presents an exploration of the perceived facilitators to successful returns to school for two primary-aged children who had previously experienced anxiety around school attendance. The perspectives of parents, school staff, and educational psychologists were gathered using semi-structured interviews to identify effective support. A reflexive thematic analysis was conducted to generate themes. Findings demonstrate that the support in each case was highly individualised. Key facilitators considered to achieve this included: effective home-school communication; taking a functional approach; engaging other professional support; cultivating positive relationships; and practitioners regularly reflecting on their practice. The significant overlap between themes supports an interactionist, ecological model of early identification and intervention for EBSNA difficulties. Implications for practitioners include the need to ensure a reflective, individualised approach, and the importance of facilitating the home-school relationship.Keywords: emotionally based school non-attendance; anxiety; school absenteeism; educational psychology; intervention<br/
ENVIRONMENTAL SUSTAINABILITY PERFORMANCE OF A MEMBRANE-BASED TECHNOLOGY FOR LIVESTOCK WASTEWATER TREATMENT WITH NUTRIENT RECOVERY
No full textThe gas-permeable membrane (GPM) technology is one of the most novel techniques capable of minimizing ammonia (NH3) emissions associated to wastewaters, while recovering nitrogen as nutrient. This study conducted for the first time a life cycle assessment of this technology (treatment scenario), to compare the environmental trade-offs with the conventional manure management (conventional scenario), and determine which strategy performs better. The environmental impact results per m3 of manure, estimated using the ReCiPe method V 1.1, indicated that the treatment scenario reduces global warming (GW) by 14% and marine eutrophication (ME) by 32% with respect to the conventional scenario, whilst it increases particulate matter formation (PMF) and terrestrial acidification (TA) by 16% and 17%, respectively, due to some NH3 volatilization. Other impact categories considered were ozone formation (affecting human health (HOF) and ecosystems (EOF)), where the treatment scenario was able to reduce this impact by 48% and 50%, respectively. For freshwater eutrophication (FE), the net value was similar for both scenarios. A sensitivity analysis looking at optimum membrane design parameters (optimized treatment scenario) resulted in further reductions between 26% and 86% for GW, ME, PMF and TA with respect to the conventional scenario, although one potential drawback is the application of higher amount of phosphorous with the organic fertilizer, which resulted in higher FE impacts. Overall, the GPM system-based treatment is more environmentally sustainable compared to the conventional scenario thus making this an attractive option for environmental management systems, especially in areas with low water quality or high nutrient imbalance. Keywords: Life cycle assessment, manure treatment, ammonia reduction, nutrient imbalance, agricultural effluents.<br/
Mineral diagenesis in a carbonate-rich mudstone: The Lower Carboniferous Hodder Shale, UK
No full textMineral authigenesis in mudstones respond differently across the compositional spectrum of fine-grained rocks resulting in a complex array of possible rock fabrics that affect the mechanical capacity of mudstones. Within carbonate-rich mudstones, geochemical controls on silicate and carbonate mineral reactions are variable and poorly understood. Here we analyse the diagenetic minerals of the carbonate-rich Hodder Mudstone from the Carboniferous Bowland Basin, UK, using SEM petrography combined with X-ray-based inorganic geochemical data. Our findings show that up to 90% of quartz cement in the samples are diagenetic in origin, originating mainly from biogenic silica dissolution, and clay mineral reactions. It is also evident that due to the varying diagenetic silica-yielding reactions, authigenic silica overgrowths and isolated authigenic quartz crystals are localised in argillaceous samples while calcareous samples are characterized by silica replacement textures and quartz/calcite intergrowths. Moreover, euhedral dolomite crystals are concentrated within argillaceous units in comparison with calcareous units which are characterised by anhedral dolomite precipitation and replacement textures. These finding presents a case for facies28 selective cementation as both early and burial diagenetic alterations were observed to be controlled by primary depositional components of biogenic debris and extrabasinal silicate detritus that resulted in complex and variable precipitation of authigenic minerals
The long-term influence of Open Access on the scientific and social impact of dental journal articles: An updated analysis
No full textObjectives: To investigate whether dental journal articles that are open access (OA) receive greater citation counts and higher Altmetric Attention Scores (AAS) than articles that are non-OA in the long term.Methods: Eligible dental journal articles published in 2013 were identified via PubMed, and Web of science, Unpaywall and corresponding URLs were manually checked to determine the OA status of each included article 7 years after publication. Citation counts were extracted from Web of Science and Scopus, and AAS was harvested from the Altmetric Explorer. Multivariable general linear regression analyses were performed to investigate the association between OA and citation count, as well as between OA and AAS.Results: Among the 755 included articles, 309 (40.9%) were freely available online. Among the 309 OA articles, articles available from publishers accounted for 64.4% (199/309) of all OA articles, and those available through self-archiving accounted for 56.0% (173/309). According to regression analyses, OA articles had significantly greater citation counts (P = 0.001) and AAS (P < 0.001) than non-OA articles.Conclusions/clinical significance: In the field of dentistry, about 41% of journal articles are OA 7 years after publication, and OA articles available from the publishers are more common than those from authors through self-archiving. OA articles tend to have greater scientific and social impact than non-OA articles in the long term.Keywords: open access; dentistry; bibliometrics; altmetrics; evidence-based dentistry; research wast
Differences in walking football initiation and maintenance influences across respondent characteristics: a cross-sectional survey in 50-75 year -old adults
No full textDespite health benefits gained from physical activity and sport participation, older adults are less likely to be active. This study investigates what influences 50–75-year-olds (N=439) to initiate and maintain walking football, across gender, socioeconomic status, number of health conditions and physical activity level. It also considers relationships between participant characteristics and influences, and intentions to play after a forced break (COVID-19). Results of a UK online cross-sectional survey found those with two or more health conditions rated social influences significantly higher in initiation and maintenance, than participants with no health conditions. Multiple regression analysis found a positive walking football culture and perceived use of maintenance resources contributed significantly to intentions to return to play after COVID-19 restrictions eased. Practitioners should consider providing opportunities for social connection, foster a positive walking football culture, and encourage players to utilise maintenance resources (e.g., scheduling sessions) in older adult walking football sessions.Keywords: behaviour change, soccer, physical activity, survey research, older adults<br/
Home-working and e-communications with colleagues during COVID-19: impact on psychological health and productivity
No full textBACKGROUND: During the COVID-19 pandemic, there has been a wide-scale shift to home working for many employees in the UK. We hypothesised that during the lockdown, employees working from home would rely more heavily on work emails and other forms of e-communications to remain connected to colleagues and the work place. We additionally hypothesised that an increase in e-communications with colleagues outside of normal working hours would be associated with poorer health and productivity. METHODS: We surveyed N=204 full-time UK-based employees during October 2019 (pre-COVID) and during April 2020 (n=153, during-COVID). Ninety-three two participants indicated that they were working exclusively from home during-COVID, and were therefore included in analyses. RESULTS: Email volume was higher during-COVID than pre-COVID, and the use of instant messaging and video calls outside of normal working hours increased. Change in email engagement outside of normal working hours was not associated with health and productivity Change in email engagement outside of normal working hours was not associated with poorer health and productivity. However, increases in other forms of e-communications during leisure time was associated with poorer physical and mental health. CONCLUSIONS: A legacy of COVID-19 may be to accelerate a trend towards greater levels of home working, therefore understanding how to maintain health and productivity when working from home will be critical to ensure business continuity. Ours is the first study to suggest that increases in work-related video calls, instant messages and social media engagement outside of normal working hours may be detrimental to employee health and productivity
First discoveries and localisations of Fast Radio Bursts with MeerTRAP: a real-time, commensal MeerKAT survey
No full textWe report on the discovery and localization of fast radio bursts (FRBs) from the MeerTRAP project, a commensal fast radiotransient-detection programme at MeerKAT in South Africa. Our hybrid approach combines a coherent search with an averagefield-of-view of 0.4 deg2 with an incoherent search utilizing a field-of-view of 1.27 deg2 (both at 1284 MHz). Here, wepresent results on the first three FRBs: FRB 20200413A (DM=1990.05 pc cm􀀀3), FRB 20200915A (DM=740.65 pc cm􀀀3),and FRB 20201123A (DM=433.55 pc cm􀀀3). FRB 20200413A was discovered only in the incoherent beam. FRB 20200915A(also discovered only in the incoherent beam) shows speckled emission in the dynamic spectrum which cannot be explained byinterstellar scintillation in our Galaxy or plasma lensing, and might be intrinsic to the source. FRB 20201123A shows a faintpost-cursor burst about 200 ms after the main burst and warrants further follow-up to confirm whether it is a repeating FRB.FRB 20201123A also exhibits significant temporal broadening consistent with scattering by a turbulent medium. The broadeningexceeds that predicted for medium along the sightline through our Galaxy.We associate this scattering with the turbulent mediumin the environment of the FRB in the host galaxy. Within the approximately 10 localization region of FRB 20201123A , weidentify one luminous galaxy (A 15•67; J173438.35􀀀504550.4) that dominates the posterior probability for a host association.The galaxy’s measured properties are consistent with other FRB hosts with secure associations
