1,720,987 research outputs found
Assessment of a geomorphological-based design for coastal protection: The case of a wave-cut platform on the Bogliasco coast (Liguria Region, NW Italy)
No full textCoastal erosion processes and the associated risks pose a significant challenge for coastal urban settlement administrations. Coastal managers are often seeking new approaches and solutions for coastal protection. Introducing protective structures such as breakwaters and groins often poses problems for management, e.g. modification of the natural panorama, changes within the local coastal dynamics and associated implications with regard to coastal hazards and risks. This paper describes a geomorphological-based approach to coastal structure design, taking as its study case the Bogliasco coast in the region of Liguria, near the eastern border of the municipality of Genova (Northwest Italy). Bogliasco is a stretch of rocky coast exposed to the most intense storms of the Liguria Sea and where the urban settlement reaches the edge of the cliff. To prevent cliff collapse and coastal flooding (and mitigate the associated risks), this study proposes an approach based on the structural recovery of an ancient wave-cut platform currently consumed by erosion. The recovered structure dissipates incoming waves, helping to mitigate both the erosive phenomena at the foot of the cliff and the risk of coastal flooding. The performance of the coastal protection project was evaluated by comparing the results of the XBeach model simulations for ante-operam and post-operam scenarios. The results indicate that the adopted solution contributes to a reduction of wave impact on the coast and the mitigation of flood hazards and risks. A geomorphological-based approach is therefore seen as a winning approach from both an engineering and management viewpoint
A Rapid Method to Identify the Effects of Coastal Artificialization on Posidonia oceanica Meadows in Coves
No full textThis study proposes a rapid and cost-effective method to identify the effects of coastal artificialization on the distribution of shallow Posidonia oceanica meadows. Seven embayed coves were selected along the Ligurian coastline (Italy, NW Mediterranean) to evaluate the influence of the coast geometry on the depth and morphology of the meadow upper limits (i.e., the shallowest depth reached by the plants towards the coastline). The areas under investigation are characterized by rocky coasts and exhibit varying degrees of embayment, resulting in different levels of exposure to wave action. The geometric features of embayed coastlines, along with hydrodynamics and physical parameters, were examined in relation to the structure of P. oceanica meadows within each cove. The results indicated that both natural and anthropogenic (i.e., artificial) coastal geometries influence the spatial distribution of P. oceanica meadows, leading to significant heterogeneity in their upper limits. The configuration of the embayment system produces various types of hydrodynamic circulation. The existence of a cellular circulation pattern leads to the formation of rip or megarip currents, which cause erosion in the shallow portions of the meadows and create sandy channels that disrupt the continuity of the meadows. Establishing a relationship between the hydrodynamics within the coves and the characteristics of the upper limits of the meadows proved to be a valuable method for promptly distinguishing whether the observed conditions stemmed from natural or human influences. This proposed approach enables a preliminary and cost-effective assessment of the origins of erosive processes affecting the shallow portions of P. oceanica meadows. Such an approach represents a clear management advantage in the environmental impact assessment of coastal engineering projects
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
Rip currents investigation on a Ligurian pocket beach, NW Mediterranean
No full textWave-induced currents play a key role in coastal sedimentary and hydrodynamics processes, and in particular, rip currents are probably the most widely studied aspect. Rip currents are characterized by a strong seaward-directed flow, which can transport sediments, planktonic organisms, nutrients, pollutants, and suspended material. However, rip currents are also a hazard for beachgoers and constitute a well known risk to bathers. Several studies have been conducted to describe rip current dynamics and their implications along oceanic beaches, although only a few studies have considered rip dynamics along Mediterranean coasts. This study is an accurate investigation of rip current development in the Levanto pocket beach (Ligurian sea, NW Italy). Coastal video-monitoring, coastal modelling, field surveys, and laboratory analysis are well known methodologies used to study the behaviour of rip currents, but each has its limitations. To overcome this problem, we propose an integrated approach where different tools are integrated among these to obtain mutual validation among several different approaches. The results show how the rip currents investigated in this study can reach and exceed velocities of 1 ms−1, comparable with those of oceanic rip currents, and how these are a key component in the coastal processes that occur along a Mediterranean pocket beach
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
Detached breakwaters, yes or not? A modelling approach to evaluate and plan their removal
No full textDetached breakwaters have been widely employed as a measure against beach erosion and for coastal protection. However, this type of structures may cause different critical issues, and the advantages are not always evident. Water stagnation, rip currents development in the gaps between multiple structures, and obstruction of the natural panorama are well-recognised issues. However, their removal is always problematic because it is generally associated with rapid erosion of the beach and high costs. This work proposes a modelling approach to obtain a preliminary evaluation of a theoretical removal intervention and discusses its possible consequences. The study case is the Moneglia beach, a tourist beach located on the eastern Ligurian coast, NW Italy. The beach is characterised by the presence of three detached breakwaters, arranged over the entire length of the beach. A dataset consisting of LiDAR data, multibeam data, single-beam data and DGPS data was used to obtain an accurate digital elevation model (DEM) of the study area. Subsequently, the XBeach model was used to simulate three scenarios: i) state-of-the-art scenario (S0), ii) detached breakwaters removal scenario (S1), iii) detached breakwaters removal scenario + nourishment (S1N). The S1 scenario was implemented to evaluate the beach morphodynamic response in the case of a removal intervention. S1N was implemented to simulate a beach recovery plan through a beach nourishment intervention. Once the S1N final scenario was obtained, XBeach was implemented to get a comparison with the sea flooding hazard in the S0 and S1 scenarios. The sea flooding hazard assessment was performed considering storm events with a return time of 50 and 100 years, respectively. The results showed both the potential of the XBeach model as a tool and the sustainability of a theoretical detached breakwater removal intervention
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