1,720,958 research outputs found
Steady streaming under a surface wave propagating over a rough bottom: A model of the bottom boundary layer
No full textThe steady streaming generated by nonlinear effects at the bottom of a propagating surface wave is determined when the bottom is characterized by a roughness, the size of which scales with the boundary layer thickness. Therefore, the cornerstone contribution by Longuet-Higgins, who considered a smooth bottom, is extended to sea waves and sandy bottoms characterized by a grain size that ranges from fine silt to fine gravel. For values of the grain size d* up to 0.05 delta* , delta* being the thickness of the viscous bottom boundary layer, the velocity profile is practically coincident with that predicted by Longuet-Higgins. If the grain size is further increased, the steady velocity component becomes larger and reaches a maximum value that is approximately 70% larger than that predicted by Longuet-Higgins. The maximum of the steady velocity component is attained for d* = 0.6 delta*. A further increase in d* leads to a decrease in the steady velocity component that, however, keeps always larger than that predicted for a smooth bottom. As the roughness size increases up to the values typical of medium sand, the steady velocity component increases. Then, a further increase in the roughness size leads to a decrease in the steady streaming even though, in the range of the roughness size presently investigated, the steady velocity component is always larger than that predicted for a smooth bottom
Sea level perturbations caused by Bora in the northern Adriatic
No full textThe Jan. 2014 Bora storm had a measurable impact in the northern Adriatic. At Senigallia, in the wake of the storm, the EsCoSed field experiment (Brocchini et al. in Geology 385:27–40, 2017) recorded 5-cm sea-level fluctuations with a characteristic period of 100 min, exhibiting a distinctive, discrete frequency spectrum. Sea level oscillations of similar height and time periods were also recorded by tidal gauge at Venice. Given the sensitivity of Venice flooding to sea-level perturbations and the localized, basin-transversal jet structure of the Bora winds, the observations are both significant and surprising. We hypothesize that the oscillations were caused by wind setup generated by the Bora jets, and investigate the event using a simplified, linear mathematical model. Model simulations support the wind setup hypothesis and suggest that the oscillations observed were a mixture of edge-waves and two-dimensional seiches with a significant basin-transversal component. The spatial structure of seiches explains the basin-longitudinal reach of Bora storm. A comparison with the analysis of Venice historical records of extreme sea level events, compiled by Ferrarin et al. (Sci Rep 12(1):1–11, 2022), shows that Bora-induced oscillations are of the same order of magnitude as general seiche constituents. Their contribution, however is, much less understood. Further work is needed to evaluate the flooding threat posed by Bora storms
Nearshore Observations and Modeling: Synergy for Coastal Flooding Prediction
No full textCoastal inundation has recently started to require significant attention worldwide. Theincreasing frequency and intensity of extreme events (sea storms, tsunami waves) are highly stressingcoastal environments by endangering a large number of residential areas, ecosystems, and touristfacilities, and also leading to potential environmental risks. Predicting such events and the generatedcoastal flooding is thus of paramount importance and can be accomplished by exploiting the potentialof different tools. An example is the combination of remote sensors, like marine radars, with numericalmodels. Specifically, while instruments like X-band radars are able to precisely reconstruct both wavefield and bathymetry up to some kilometers off the coast, wave-resolving Boussinesq-type models canreproduce the wave propagation in the nearshore area and the consequent coastal flooding. Hence,starting from baseline simulations of wave propagation and the conversion of water elevation resultsinto radar images, the present work illustrates the reconstruction of coastal data (wave field andseabed depth) using a specifically suited data processing method, named the “Local Method”, andthe use of such coastal data to run numerical simulations of coastal inundation in different scenarios.Such scenarios were built using two different European beaches, i.e., Senigallia (Italy) and Oostende(Belgium), and three different directional spreading values to evaluate the performances in cases ofeither long- or short-crested waves. Both baseline and inundation simulations were run using theFUNWAVE-TVD solver. The overall validation of the methodology, in terms of maximum inundation,shows its good performance, especially in cases of short-crested wind waves. Furthermore, theapplication on Oostende Beach demonstrates that the present methodology might work using onlyopen-access tools, providing an easy investigation of coastal inundation and potential low-costintegration into early warning system
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
- …
