1,722,027 research outputs found
Potential secondary transmission of SARS-CoV-2 via wastewater
No full textThe new coronavirus, SARS-CoV-2, has spread internationally and whilst the current focus of those dealing with the COVID-19 pandemic is understandably restricting its direct transmission, the potential for secondary transmission via wastewater should not be underestimated. The virus has been identified in human fecal and wastewater samples from different countries and potential cases of transmission via wastewater have been reported. Our recommendations for hospital wastewater treatment, municipal wastewater plants, sewage sludge, water reuse and aquatic environments are designed to reduce the risk of such transmission, and contribute to limiting the resurgence of COVID-19 as current restrictions are relaxed. A particular urgent recommendation focusses on supporting low-income countries in tackling the potential for secondary transmission via wastewater
[4 + 1] Annulation of in situ generated azoalkenes with amines: A powerful approach to access 1-substituted 1,2,3-triazoles
No full text1-Substituted 1,2,3-triazoles represents ‘privileged’ structural scaffolds of many clinical pharmaceuticals. However, the traditional methods for their preparation mainly rely on thermal [3 + 2] cycloaddition of potentially dangerous acetylene and azides. Here we report a base-mediated [4 + 1] annulation of azoalkenes generated in situ from readily available difluoroacetaldehyde N-tosylhydrazones (DFHZ-Ts) with amines under relatively mild conditions. This azide- and acetylene-free strategy provides facile access to diverse 1-substituted 1,2,3-triazole derivatives in high yield in a regiospecific manner. This transformation has great functional group tolerance and can suit a broad substrate scope. Furthermore, the application of this novel methodology in the gram-scale synthesis of an antibiotic drug PH-027 and in the late-stage derivatization of several bioactive small molecules and clinical drugs demonstrated its generality, practicability and applicability
Cleavage of carbon-carbon bonds by radical reactions
No full textIn recent years, radical C-C bond cleavage reactions have been increasingly understood and used to perform transformations that complement traditional ionic processes. However, to date radical C-C bond cleavage/functionalization reactions have not been the subject of a dedicated review. Herein we summarize the most recent and significant developments in the radical activation and functionalization of carbon-carbon bonds, with an emphasis on both synthetic outcomes and reaction mechanisms, and highlight how these radical C-C bond cleavage reactions enable challenging transformations
Context Correlation Aware Network for Cardiac Segmentation
No full textAutomatically segmenting the anatomical structure of the heart from the cardiac magnetic resonance (CMR) images offers a great potential to augment the traditional healthcare strategy for the quantitative analysis of cardiac contractile function. Most of the existing CNN-based methods for cardiac segmentation tend to ignore the misalignment issues during the feature aggregation process and not fully use multi-scale context and contour information, which may lead to the unexpected misclassification caused by the falsely aligned contextual features and the discontinuity in the edge of segmentation maps. To resolve these issues, we proposed a context correlation aware network (CCA-Net). In CCA-Net, a volume correlation flow module was designed to align contour features and semantic features from adjacent levels, which offered the guidance to wrap low-resolution semantic features into high-resolution features. Besides, a residual gated squeeze module was utilized to explicitly model the boundaries and enhance the representations. Extensive experiments on the multi-sequence cardiac magnetic resonance segmentation challenge (MS-CMRSeg 2019) dataset and MICCAI challenge 2017 automatic cardiac diagnosis challenge (ACDC) dataset demonstrated that CCA-Net was superior to other state-of-the-art methods
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
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