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Chapter 1: Selenium in the environment
No full textSelenium contamination of air, aquatic environments, soils and sediments is a serious environmental concern of increasing importance. Selenium has a paradoxical feature in bringing about health benefits under the prescribed level, but only a few fold increase in its concentration causes deleterious effects to flora and fauna, humans and the environment.
This book Environmental Technologies to Treat Selenium Pollution: Principles and Engineering:
presents the fundamentals of the biogeochemical selenium cycle and which imbalances in this cycle result in pollution.
overviews chemical and biological technologies for successful treatment of selenium contaminated water, air, soils and sediments.
explores the recovery of value-added products from selenium laden waste streams, including biofortication and selenium-based nanoparticles and quantum dots.
This book may serve both as an advanced textbook for undergraduate and graduate students majoring in environmental sciences, technology or engineering as well as as a handbook for tertiary educators, researchers, professionals and policy makers who conduct research and practices in selenium related fields. It is essential reading for consulting companies when dealing with selenium related environmental (bio)technologies
Environmental relevance of solid by-products from Municipal Solid Waste Incineration assessed by combining magnetic and mineralogical analysis
No full textBottom (BA) and Fly Ashes (FA) from Municipal Solid Waste Incineration (MSWI) represent huge amounts of solid by-products that still pose environmental and health problems. Some routes for MSWI ashes management/reuse have been proposed (e.g., inertization, landfilling, reuse as filler, geopolymers), but not all of BA and FA hazardous components are fully understood. Precise identification of minerals from BA and FA is challenging due to several factors: high number of phases, MSWI combustion temperature, and variable chemical composition of feedstock materials. In addition, (trans)formation of magnetic iron oxides, which have been correlated with heavy metals pollution and the presence of toxic ultrafine superparamagnetic (SP) grains in a range of materials, occurs during incineration and quenching.
We have undertaken the study of BA and FA samples from Italian MSWI plants by combining magnetic and mineralogical analysis for probing mineralogy and the extent of SP grains. The BA and FA samples are characterized by narrow hysteresis curves and low coercivity (Bc, 7.2 – 14.1 mT), suggesting significant reversible component of magnetization. Also, the analysis of thermomagnetic properties shows that both BA and FA gain magnetization during cooling. The Low temperature remanent curves by Magnetic Properties Measurement System (MPMS) show magnetite-like shapes for most of samples, but the Vervey transition in FA samples is not clear probably due to the presence of oxidized/impure magnetite or unblocking of SP grains. Measurements of AC susceptibility by MPMS might support the fact of a significant contribution of SP grains in FA (FA show larger frequency dependence than BA). We performed XRD analysis on FA and BA samples, including different magnetic extracts of BA in order to shed some light on iron oxides phases. The main mineralogical phases found in BA are quartz, calcite-vaterite, melilite group minerals and plagioclase; FA contain Ca-aluminosilicates and more sulphates and chlorides with respect to the BA. Iron oxides such as wurstite, hematite, and the magnetic spinel-type iron oxides are noted both in BA and FA. The XRD pattern on BA magnetic extracts confirms that magnetite or impure spinel-type iron oxides (e.g., Mg-magnetite, Ti-magnetite, and maghemite) are in charge of their strong magnetic response. However, on the basis of previously obtained chemical analysis, the presence of impure magnetite containing Cr, Zn, Mn, and Cu cannot be ruled out neither in BA nor in FA. Rietveld refinement to assess the extent of minor metals substitution is ongoing. These preliminary observations emphasise the metastable nature of MSWI ashes and might lead to a better assessment of the environmental impact related to iron oxides
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
Venting and seepage systems associated with mud volcanoes and mud diapirs in the southern Tyrrhenian Sea
No full textHigh resolution swath bathymetry and backscatter data, seismic CHIRP profiles, multibeam water column acoustic measurements and sediment samples were collected on a cold seep province in the southeastern Tyrrhenian Sea, at a water depth of 500-1000. m. The mud volcanoes, characterized by a high backscatter signature, are the site of gas venting at the seafloor that formed a 630-m-high plume in the water column. The mud volcanoes feature a precipitation of iron-oxy-hydroxide crusts and pyritized and Sulfur burrows in the sub-surface and authigenic siderites, also cementing burrows, further down, showing a sharp transition from the oxic zone toward the sulfate-methanogenic zone.The mud flows are characterized by an intermediate backscatter seafloor and by the presence of gas in the sediment only 2. m below the seafloor. The mud flows consist of 1-m-thick drapes of water-rich mud extending downslope from the mud volcanoes. They act as sealing layers that prevent large fluxes of gas venting at the seafloor (low venting) and favor oxic conditions close to the sediment-water interface and the abundant precipitation of post-oxic siderites a few meters below the seafloor.The mud diapirs are characterized by a low backscatter seafloor and large fields of pockmarks. In coincidence with the normal faults, organogenic carbonate crusts form at or very close to the seafloor and are associated with chemosymbiontic bivalves (lucinids). The youngest shells are AMS radiocarbon dated 640-440. BP, suggesting that the seepage activity may have been clogged by the carbonates, only very recently.Similarities between the normal faults in the study area and the tectonic setting of the inland Calabrian Arc show that normal faults can control the location of fluid pathways and, probably, also the rising of the mud diapir
Magnetic characterization of solid byproducts from Municipal Solid Waste Incinerators
Full text linkThe main objective of my visit to the IRM was to explore the magnetic properties of the solid by-products,
i.e., bottom (BA) and fly ashes (FA), deriving from municipal solid waste incinerators. The goal of this project is to decipher the sources of the magnetic properties previously observed in the BA and
FA (Funari et al., 2016), and estimate the concentration of SP grains
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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