1,720,966 research outputs found
Vulnerability assessment to trihalomethane exposure in water distribution system.
Full text linkChlorination is an effective and cheap disinfectant for preventing waterborne diseases-causing microorganisms, but its compounds tend to react with the natural organic matter (NOM), forming potentially harmful and unwanted disinfection by-products (DBPs) such as trihalomethanes (THMs), haloacetic acids (HAAs), and others. The present paper proposes a methodology for estimating the vulnerability with respect to users' exposure to DPBs in water distribution systems (WDSs). The presented application considers total THMs (TTHMs) concentration, but the methodology can be used also for other types of DPBs. Five vulnerability indexes are adopted that furnish different kinds of information about the exposure. The methodology is applied to five case studies, and the results suggest that the introduced indexes identify different critical areas in respect to elevated concentrations of TTHMs. In this way, the use of the proposed methodology allows identifying the higher risk nodes with respect to the different kinds of exposure, whether it is a short period of exposure to high TTHMs values, or chronic exposure to low concentrations. The application of the methodology furnishes useful information for an optimal WDS management, for planning system modifications and district sectorization taking into account water quality
Drinking Water Vulnerability Assessment after Disinfection through Chlorine
No full textAbstractThe objective of present paper is to propose a criterion for performing a vulnerability analysis in a water distribution system, which involves the estimation of the consumers’ exposure to pathogenic risk and to elevated trihalomethanes concentration, deriving from the reaction of natural organic matter with sodium hypochlorite, widely used for the drinking water disinfection.The analysis is carried out by introducing some index parameters, linked to a trihalomethanes fixed threshold, which has not to be exceeded. The results of the methodology show that the considered factors identify different vulnerable nodes respect to the different kind of exposure they refer to
Primary intestinal choriocarcinoma in a patient with long-standing Crohn’s disease
Full text linkExtra-gonadal choriocarcinoma is an extremely rare highly malignant neoplasm with a poor prognosis. In the gastrointestinal tract it usually arises in stomach, esophagous, bowel intestine and colon. Only few cases are pure and not associated with a classic adenocarcinoma. The correlation of Crohn’s disease with choriocarcinoma is not reported. We describe a case of 47-year old man with primary choriocarcinoma of the colon in a previously documented Crohn’s disease
Vulnerability assessment after chlorine disinfection in drinking water distribution system
No full textDisinfection of drinking water is usually achieved by means of chlorine compounds for their effectiveness and low cost.
They ensure a residual concentration in the water supply system (WSS), which reduces the risk of pathogenic
contamination and limits the proliferation of microbial species. However, chlorine reacts with the organic matter in the
water producing disinfection byproducts (DBPs). Some DBPs, such as trihalomethanes (THMs) have carci nogenic effects
on human health and then their concentration has to be monitored and maintained below fixed values. In this context, the
objective of present paper is to show a procedure for performing a vulnerability analysis respect elevated THMs exposure
in WSS. The introduction of specific index parameters allows to identify the more critical nodes of the system respect to
different kind of exposure, high concentration exposure for a short period or chronic exposure to low THMs concentrations,
which are both important for epidemiological studies. The analysis is applied to the real water distribution system of
Cimitile, a town in South Italy, in which water is disinfected through sodium hypochlorite. The results show that the
considered parameters identify different vulnerable nodes respect to the different kind of exposure. The presented
procedure may be also useful for implementing methodologies for the optimization of the chlorination process in water
supply systems
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
- …
