1,720,969 research outputs found
Survival of Cryptosporidium parvum in faecal wastes and salad crops
No full textCryptosporidium parvum is a protozoan parasite of man and a range of animals. An essential stage of the life cycle is the formation in the gastrointestinal tract of oocysts, each containing four infectious sporozoites. Thick wall oocysts are shed in apparently normal or diarrhoetic faeces to contaminate soil and water, providing routes into the food chain. Desiccation and snap freezing are lethal to oocysts. Nevertheless, the robust coat affords significant protection against environmental stressors such as low pH or water activity, temperatures above freezing and a range of sanitising and oxidizing agents such as chlorine. C. parvum may therefore survive in the environment for extending periods of time, posing a threat to animals and man if ingested either directly in contaminated water or in uncooked/ improperly cooked foods which are cropped from contaminated land. This threat has only partially be characterized, due in part to the difficulty in recovering oocysts and other pathogens from complex matrices such as manures and salad leaf surfaces.Accordingly, this study describes improved methods for the recovery of oocysts from faecal waste samples and salad crops, with recovery efficiencies of 40-80%. Using these improved tools, the results of oocyst survival studies in the stored wastes and on salad leaves are presented to show the suitability and drawbacks of current practices to minimize entry and spread of C. parvum in the food chai
New insights into the antimicrobial mechanisms of copper touch surfaces
No full textSurvival of pathogens on touch surfaces contributes to increasing incidence and spread of antibiotic resistance and infection in hospitals. One way to address this could be to use biocidal surfaces in conjunction with improved cleaning regimes. Exposure to moist copper alloy surfaces, to simulate fomite contamination, resulted in a rapid kill of significant bacterial, viral and fungal pathogens. We now report studies on dry surfaces with a range of pathogens to elucidate the antimicrobial mechanism
Correction: Inactivation of norovirus on dry copper alloy surfaces (PLoS ONE (2013) 8, 9 (e75017) DOI: 10.1371/journal.pone.0075017)
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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
Urinary epidermal growth factor (hEGF) levels in patients with carcinomas of the breast, colon and rectum
No full textA specific two-site ELISA for human epidermal growth factor (hEGF) has been used to measure urinary hEGF/creatinine ratios in 30 normal subjects, 30 hospital in-patients with breast cancer and 30 hospital in-patients with colonic or rectal cancer. There was no significant difference between patients with breast cancer and controls. Although a statistically significant difference between patients with colorectal cancer and controls was observed, the biological significance of this observation is doubtful. No clear effect of the presence of breast or colorectal carcinoma on the urinary excretion of hEGF has been observed
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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