1,720,995 research outputs found
Working in a Team: Development of a Device for Water Hardness Sensing Based on an Arduino-Nanoparticle System
No full textThis work describes a two-year project carried out in an Italian technical high school. Through integrated work, the activity involved the efforts of different teachers and students, particularly those in the Chemical, Electronic, and IT departments. They merged their complementary skills to create an inexpensive device that quickly measures water hardness. The pedagogical aspect of this work aimed to support and reinforce development of the key competences for lifelong learning recommended by the European Commission, especially by strengthening the logical-mathematical, digital, and social skills of the students. The device made is based on an Arduino board connected to a red LED and an optical sensor. The device is able to read the intensity of light transmitted through the sample and to independently convert this output into the water hardness expressed in French degrees. The color change used as information transducer is due to the aggregation of negative gold nanoparticles induced by the bivalent cations in solution. Working in school laboratories under teacher supervision, students connected and troubleshot the hardware system, synthesized and characterized the gold nanoparticles, and developed the software. Finally, the system was assembled inside a box composed of a rigid container, a sample holder, and a touchscreen display. Instructions for replicating this instrument are reported in the paper, while further details and explanations for instructors and students are provided in the Supporting Information
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Synthesis, Purification, and Characterization of Negatively Charged Gold Nanoparticles for Cation Sensing
No full textIn recent years, nanotechnology has been one of the major subjects of scientific and technological research. Currently, several applications of nanotechnologies are already available on the market. Particularly relevant are the fields of new materials and sensors, which have excellent potential future applications in the biomedical field. This paper describes a project in which the students were challenged to investigate the properties of gold nanoparticles they synthesized themselves. The activity, suitable for students with good chemical knowledge (last year of high school), is divided into three parts, each taking 2 h. In the first part, gold nanoparticles are synthesized and functionalized. In the second, students purify the sample and analyze its optical properties, focusing on the noncovalent interaction with metallic ions. Last (part three), the students realize a chemosensor for cations using the nanoparticles synthesized. At the end of the project, students use the sensing system they had set up to analyze an unknown sample containing bivalent or monovalent metal cations. The proposed activity turned out to be strongly motivating for the students involved and definitely improved their knowledge in the nanomaterials field. Different analytical techniques, such as UV–vis spectrometry, GPC, and TGA, were used, and consequently, both the understanding and the ability to use them were reinforced
Multidisciplinary approach to provide detailed conceptual model of the aquifer systems: an example in the Versilian coastal plain (NW Tuscany)
No full textDetailed conceptual models of the aquifer systems are an essential base working for groundwater modelling and for a correct groundwater resources management. At the same time the right approach to obtain reliable conceptual models is certainly interdisciplinary, which guarantees the knowledge of geological, hydrogeological and geochemical features of the aquifer systems.
In this contribute an example of multidisciplinary study carried out on the Versilian coastal plain aquifers (NW Tuscany) is presented, underlining as the comparison between geological framework and hydraulic, hydrodynamic, chemical and isotopic data allowed at understanding the feeding mechanism of groundwater flow and at defining the seawater-freshwater mixing process.
The study area has an extension of about 55 kmq and it has delimitated by Poveromo and Motrone ditch, northward and southward respectively, and by shoreline and Apuan Alps, in the western and eastern parts. The Versilian plain constitutes a recent succession of alternating continental and marine deposits. Hydrostratigraphic cross-sections reaching a depth of about 80-100 metres were elaborated. Aquitards/aquicludes are locally interbedded to the prevalent aquifer terms, which are mainly made up by sand and gravel. Gravel is shallow in the inner portion of the plain, where the alluvial fan of Versilia River is present. Seaward gravel deepens and is overlain by sands. For this framework the aquifer results throughout a phreatic monolayer, although the local presence of superficial silty-clayey or peaty deposits may determine confined or semi-confined conditions. Moreover, the presence of a discontinuos subsurface layer of conglomerate and silty-clayley lenses may locally separate the groundwater flow in multiple levels.
In order to achieve the purpose of the present work, multiple types of hydrogeological and hydrodinamics surveys and chemical and isotopic analyses on water samples were performed. In details, two piezometric surveys and physical-chemical analyses (temperature, electrical conductivity, pH, Eh) were carried out in April 2009 (high level condition) and in September 2009 (low level condition). On the whole, 192 wells and 14 stream water points were examined.
Piezometric and iso-conductive maps suggest as the recharge area of the coastal plain is mainly the alluvial fan. Afterwards, more detailed hydrogeochemical analyses were performed. Major elements (Ca, Mg, Na, K, Cl, NO3, SO4, HCO3), some minor elements (Br, F, B, As, Fe, Mn, Pb, Cr, Cu, Ni, Zn) concentration and some isotopic ratios (2H/1H, 18O/16O for water and 13C/12C of total inorganic carbon dissolved) were estimated.
Vertical logs were also performed in order to measure the electrical conductivity and temperature into 10 wells next to the coastline. In addition, in the apex of the fan a long term pumping test was executed, determining the aquifer hydraulic parameters (K, T, S). The last, together with the potentiometric surface, allowed us estimating the groundwater flow rate at the section corresponding to the Versilia River entrance into the plain.
Finally, comparing all data, it was possible to identify the principal component which supplies the coastal aquifer system starting from the upper part of the plain, where the Versilia River feeds the groundwater hosted in its alluvial fan. Secondary contributes are linkable to the local rainfall infiltration, well recognized in the dune sand, and to the groundwater flow coming from some fractured complexes bordering the plain. Freshwater-seawater mixing processes were also individuated
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