1,722,679 research outputs found
Mineral and biological contamination of soil and Capsicum annuum irrigated with recycled domestic wastewater
No full textDue to water scarcity in many arid countries, there is considerable interest in recycling wastewater streams such as treated urban wastewater for irrigation in the agricultural sector. The aim of this study is to assess the contamination of soil and Capsicum annuum (grown in pots) irrigated by domestic wastewaters treated by different wetland types between September 2013 and September 2014. The objectives were to assess (a) the suitability of the irrigation water for growth when using recycled wastewater contaminated by trace minerals and pathogens, (b) the impact of differently treated wastewaters on soil and fruits as a function of the wetland type, and (c) the marketable yield of the harvest as a function of mineral and biological contamination risk. Ortho-phosphate-phosphorus, ammonia–nitrogen, potassium and manganese concentrations in the irrigation water considerably exceeded the thresholds. High contamination levels by total coliforms, Salmonella spp. and Streptococcus spp. were detected. No mineral contamination was observed in the soils due to irrigation with treated wastewater. Results showed that slight to moderate zinc contamination was detected in some vegetables. Potassium accumulation in the yield showed the highest values followed by zinc. In contrast, the lowest mineral accumulation of the yield was observed for iron. No bacterial contamination was detected for fruits harvested from plants irrigated by wetland outflow water. In contrast, fruits harvested from those plants irrigated by preliminary treated wastewater showed high contamination by total coliforms, Streptococcus spp. and Salmonella spp. especially for fruits, which were located close to the contaminated soil surface. However, findings indicate that vegetables receiving wastewater treated with wetlands can be considered as safe compared to those receiving only preliminary treated wastewater. High yields in terms of economic return were associated with tap water and an organic growth medium, and a wetland with a small aggregate size and a low contact time
Trace Analytical and Electroantennographic Examination of Volatiles Released by Potential Host Trees and Volatiles Induced by Anoplophora glabripennis Infestation
No full textTrace Analytical and Electroantennographic Examination of Volatiles Released by Potential Host Trees and Volatiles Induced by Anoplophora glabripennis Infestation
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Systematic analysis of RBE and related quantities using a database of cell survival experiments with ion beam irradiation
No full textFor tumor therapy with light ions and for experimental aspects in particle radiobiology the relative biological effectiveness (RBE) is an important quantity to describe the increased effectiveness of particle radiation. By establishing and analysing a database of ion and photon cell survival data, some remarkable properties of RBE-related quantities were observed. The database consists of 855 in vitro cell survival experiments after ion and photon irradiation. The experiments comprise curves obtained in different labs, using different ion species, different irradiation modalities, the whole range of accessible energies and linear energy transfers (LETs) and various cell types. Each survival curve has been parameterized using the linear-quadratic (LQ) model. The photon parameters, α and β, appear to be slightly anti-correlated, which might point toward an underlying biological mechanism. The RBE values derived from the survival curves support the known dependence of RBE on LET, on particle species and dose. A positive correlation of RBE with the ratio α/β of the photon LQ parameters is found at low doses, which unexpectedly changes to a negative correlation at high doses. Furthermore, we investigated the course of the β coefficient of the LQ model with increasing LET, finding typically a slight initial increase and a final falloff to zero. The observed fluctuations in RBE values of comparable experiments resemble overall RBE uncertainties, which is of relevance for treatment planning. The database can also be used for extensive testing of RBE models. We thus compare simulations with the local effect model to achieve this goal. © 2012 The Author 2012
Modeling cell survival after irradiation with ultrasoft X rays using the giant loop binary lesion model
No full textWe present an application of the Giant LOop Binary LEsion (GLOBLE) model to the case of cell killing after irradiation with ultrasoft X rays. The model is based on the analysis of DSB clustering on the level of chromatin organization on a megabase pair length scale; it distinguishes between two classes of damage, characterized by either an isolated, single DSB (iDSB) or multiple, clustered DSB (cDSB) within a single giant loop. These corresponding fractions of iDSB and cDSB depend on the total number of DSB and thus on the dose as well as the yield of DSB per Gy per cell. Based on the increased yield of DSB with decreasing photon energy as reported in the literature, we demonstrate that according to the model this increased yield of DSB is sufficient to explain the increased RBE of ultrasoft X rays. Further assumptions as e.g., a higher lethality of individual DSB induced by ultrasoft X rays compared to high-energy photons, which might be a consequence of the more localized energy deposition, seem not to be a prerequisite. Since the model is also suitable to take into account local dose variations within the cell nucleus, we further analyze the impact of attenuation of low-energy photon radiation when penetrating a cell layer. We show that the inhomogenous dose distribution resulting from attenuation further increases the effectiveness and particularly affects the beta-term of the corresponding dose response curve. Finally, we compare and discuss the mechanisms of increased RBE as observed after ultrasoft X-ray irradiation with those observed after high-LET ion beam irradiation. © 2014 by Radiation Research Society
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