1,721,008 research outputs found
Holistic Approach to Water Quality: Biotic and Abiotic Contaminations in Water
Full text linkEffectively addressing water contamination requires a comprehensive approach that considers both biological and chemical contaminants, highlighting their interconnected impact and presents an accurate picture of the real environmental conditions. Microplastics (MP), per- and polyfluoroalkyl substances (PFAS) and antibiotic-resistant bacteria (ARB) coexist in real-world environments. These stressors are considered emerging waterborne contaminants. The interaction between MP/PFAS and ARB may synergistically impact several endpoints, potentially exacerbating environmental risks and posing significant challenges to water management systems and human health. This thesis is structured into two primary sections. The first part focuses on chemical contamination (MP and PFAS) in water systems, investigating their toxicological impact on Daphnia magna, a sentinel species for assessing ecological health due to its sensitivity to water quality changes. The second part investigates drinking water contamination from a microbiological perspective with a focus on ARB, providing a comprehensive analysis of water quality concerns. Research on environmentally relevant concentrations of MP/PFAS, their combined effects, and their interactions within ecosystems remains limited. A chronic toxicity exposure test was conducted on two genotypes of Daphnia magna with different exposure histories to chemicals (naive and experienced). The experimental setup mimicked natural environmental conditions to investigate Daphnia’s ecotoxicological response to the individual and combined effects of MP, PFOA and PFOS. This study enhances our understanding of the mechanisms of toxicity triggered by these environmental stressors and their impact on Daphnia’s life history traits and overall fitness throughout its life cycle. It was discovered that the stressors negatively affected the plasticity in both genotypes. However, the naive genotype exhibited greater tolerance to chemical stressors than the experienced genotype. The interactions between these chemicals were also investigated. Prior to chronic exposure, a proof-of-concept study was conducted to optimise the experimental design using Daphnia magna to assess the ingestion, retention and egestion rates of four common MP both in the presence and absence of algae as a food source. This groundwork prepared the study for chronic exposure and helped validate key techniques, such as MP characterisation, their concentration, dispersal methods, refining the choice of one MP and ensuring that the study is well-designed and methodologically accurate. Despite the significance of ARB as emerging biological contaminants, comparatively little research has focused on their presence, diversity, and concentration within household drinking water systems compared to clinical or wastewater systems. Research into the isolation, characterisation and identification of ARB from household drinking systems addresses a critical gap in understanding how these bacteria persist and proliferate in domestic environments. In the next phase of this thesis, the presence, prevalence, and diversity of ARB were investigated in three sites (showerheads, bathroom taps and kitchen taps) within 30 residences. This study provides valuable insight into the link between environmental ARB contamination in community settings and the quality of treated wastewater. This knowledge enhances our understanding of their environmental and public health implications, supports the development of effective mitigation strategies, and promotes increased public awareness of antimicrobial resistance. This thesis emphasises the need to incorporate realistic environmental conditions to accurately represent natural processes and better understand the impacts and interactions of these contaminants on the environment and humans, inspiring further research in this critical field
A Novel Condition Assessment Technique For Railway Track Substructure Using Soft Computing
Full text linkThe railway infrastructure in the UK is one of the oldest transportation systems in the world. Substructure is a key component of railway track, and similar to other surface transportation systems, track substructures are subjected to ageing and deterioration. Additionally, drainage malfunction in railway track substructure causes local soil weakness that, subsequently, can lead to railway failure. Although there are different destructive and non-destructive tests (NDTs) used in railway substructure condition assessment, there is limited knowledge about how to interpret surface deflection data for the purpose of substructure condition assessment. Limited knowledge about the current conditions of substructure layers in the presence of any local structural weakness can lead to the employment of inefficient and time- and cost-consuming maintenance actions. Therefore, this research proposes the use of a novel back-analysis technique to interpret and estimate the stiffness properties of substructure components using a falling weight deflectometer test data (a well-established and widely used NDT in the UK) and to detect any existing local anomalies in the ground layers. The proposed technique is an integration of an artificial neural network (ANN) with metaheuristic optimisation algorithms. In this regard, where the ANN surrogate forward model is trained based on a database generated by the validated finite element (FE) models. The results indicate that the proposed hybrid technique is a reliable approach to estimating substructure’s layer moduli, as well as identifying a weakness zone’s modulus and its geometrical properties. The corresponding limitations of the proposed technique are then discussed, and further avenues of research are suggested
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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