1,724,669 research outputs found
Development and application of a three-dimensional water quality model in a partially-mixed estuary, Southampton Water, UK
No full textThe aim of this research was to develop a 'transportable' water quality model for the Solent and Southampton Water estuarine system, as a part of an effort to examine the effects of human activity and natural processes on estuarine water quality. Dissolved oxygen (DO), as a main indicator of water quality, is influenced by physical, chemical and biological processes, and has been chosen as the core parameter to link the different processes to be modelled. Monthly surveys of DO, planktonic community respiration rates and other water quality parameters (temperature, salinity, chlorophyll, suspended particulate matter, inorganic nutrients etc.) in the Itchen Estuary and Southampton Water were conducted from January 1998 to April 1999. DO data shows that Southampton Water is a relatively healthy estuary, despite receiving considerable loads of oxygen demanding organic sewage effluent discharged from a number of points. A persistent moderate DO sag (DO saturation > 80%) was observed in the upper Itchen Estuary throughout the year. In the lower Itchen Estuary and Southampton Water, the waters were DO saturated during the non-phytoplankton growth season. Surface DO supersaturation was observed during the phytoplankton growth season especially during algal blooms, but no severe DO depletion was detected following the bloom collapse. Community respiration rates maintained a substantial level in the upper Itchen estuary, while in the lower estuary respiration rates were low during the non-phytoplankton season and increased during the phytoplankton growth season. It is suggested that the high winter respiration rate in the upper Itchen Estuary are sustained by inputs from external sources (rivers, sewage and industrial effluents) and that the summer increase in the lower estuary is a consequence of phytoplankton photosynthesis. Nutrients in the Itchen Estuary and Southampton Water show mainly conservative behaviour in a plot of nutrient concentration against salinity. The removal of the nutrients by phytoplankton activity occurred at high salinities during the spring to summer period.A 3-D finite element baroclinic hydrodynamic model with two-equation q2-q2l turbulence closure has been developed including a mass conservation scheme. The model successfully simulated the tides, tidal currents, and estuarine circulation in the Southampton Water and Solent estuarine system. The modelled tidal induced residual currents and water mass transportation in Southampton Water and the Solent have been examined. Model results show the existence of a predominant westward tidal induced residual current in the Solent. The tidal induced residual water mass transport is extremely limited in Southampton Water, except near the entrance to Southampton Water, where it joins the Solent. The estuarine circulation with surface, seaward flowing fresher water and bottom, landward flowing saltier water provides the main mechanism for water mass transport in the model. The short residence time of waters in the estuary estimated from the survey salinity data confirmed how effective the estuarine circulation is for sea water from the Solent to replace the water within Southampton Water. The trapping effect of estuarine circulation is also crucial for the water quality in the estuary. A water quality model has been developed and coupled with the 3-D hydrodynamic model. The water quality model consists of an external (dissolved oxygen-biochemical oxygen demand) model, which models the direct impact of external inputs (riverine discharge, domestic and industrial effluents) to the water quality, and an internal model, which simulates the impact of local estuarine phytoplankton growth on the water quality. DO and dissolved inorganic nutrients are the 'link substances' between the external model and internal model. The integrated water quality model output has been compared against the survey data for 1998, and has been shown to reproduce the spatial and temporal change in oxygen, nutrients, chlorophyll and planktonic respiration in Southampton Water
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
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