1,720,952 research outputs found
Analysis of the Interannual Variability of the Amazon-Orinoco River Plume: and its effects on Sea Surface Temperatures in the Caribbean Sea
No full textTheAmazon-Orinoco river plume is a buoyant freshwater lens of 1.2 × 106km2, which has been traced over 2000 km from the Amazon river mouthinto the Caribbean Sea and along the Lesser Antilles. The river plume iswarmer than the surrounding open-ocean waters, with temperaturedifferences up to 1.5 ∘C caused by a stratification-induced barrier layerinhibiting vertical mixing and coloured matter increasing solar energyabsorption. Due to its magnitude, the river plume affects thehydrodynamics and the oceanic conditions in the Western Tropical NorthAtlantic (WTNA) substantially, but its variations on interannual time scales andthe corresponding relation to local sea-surface temperature (SST) are notwell understood. The Caribbean Sea is a region of high ecological value as itis home to extensive coral reefs, which are especially sensitive topersistent high SST. Therefore, this study investigates the interannualvariability of the Amazon-Orinoco river plume and its relationship to SSTsin the Caribbean Sea and the WTNA. It is hypothesised that fresh anomaliesof the river plume salinity pattern are indicative of a more extensivetransportation of the heat contained in the river plume. As a result, itis expected that interannual variations of dominant river plume pathwaysaffect the magnitude and location of anomalous SSTs. To test thishypothesis, model reanalysis fields of oceanic conditions from 1993 to 2017are used to conduct statistical analyses. In this context, the river plumevariability is determined using specific regions of freshwater influenceestablished using Empirical Orthogonal Function (EOF) analysis ofanomalous sea-surface salinity (SSS). Cross-correlations analysis relatingthese EOF modes of with atmospheric processes show that the interannualvariability of the river plume is dominated by wind-inducedadvective transport and -mixing. Strong winds along the Brazilian shelfare related locally increased SSS, while a weak southward component makesfor extensive spreading of the low-salinity plume waters. Additionally, weshow that high river discharge affects SSS east of the Lesser Antillesafter a lag of three months. Through its modulation of these atmosphericprocesses, there is a strong indication that the El Niño-SouthernOscillation affects SSS variability in the main along-shelf northwestplume pathway, with low SSS 1–9 months after a La Niña event. DecreasedSSS are found in phases 2 and 3 of the Madden-Julian Oscillation, whileincreased SSS was observed in phases 6 and 7. However, the evidence forthis relation is weak and should be investigated in further research.The results show that, opposed to the hypothesis,a more extensive river plume is not associated with higher SSTs in theCaribbean Sea. However, strong correlations are found between river plumesurface area and SSTs at a lag of 1 year. Based upon results of previousstudies, we argue that the river plume has the ability to pre-heat themixed layer in the WTNA leading to extreme temperatures in the followingyear. It is wise to conduct a Lagrangian parcel back-tracking experimentto verify this mechanism. Civil Engineering | Hydraulic Engineerin
Analysis of two coastal lagoons in Ghana
No full textTwo polluted Ghanaian lagoons are investigated and possible engineering solutions are suggested and researched.The first lagoon is the Sakumo lagoon, located between Accra and Tema. This lagoon is connected to the sea through a small culvert, which enables a limited amount of water exchange. Since a few years, fishermen have been unable to catch fish in this lagoon, because of invasive plants restraining them from entering the basin. The siltation rate is high due to increasing friction because of these plants and limited sediment outflow through the small culvert. Furthermore, the water quality in the lagoon is poor. An overland flow model and a mixing model are used to evaluate the effects of a change in layout of the lagoon mouth. From this, it follows that a larger connection to the sea is beneficial to the water quality while still maintaining flood safety. However, decisions on the redesign of this lagoon mouth should be made with close regard to stakeholder interests.The second lagoon is the Klottey lagoon, located in the city centre of Accra. The surroundings of this lagoon are planned to become an area of tourism. Neighbouring the lagoon, a new fishing harbour is planned. The water quality in this lagoon is poor and its water flows along the shore of Accra. The water quality in and near the lagoon is investigated with the development plans of the area in mind. Furthermore, the shoreline response as a result of these interventions is assessed.<br/
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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
- …
