1,720,961 research outputs found
Extreme erosion of a dune crest within a short timespan (january – september 2016): the recent case in the Migliarino – San Rossore – Massaciuccoli Regional Park (Tuscany,Italy)
No full textBeach erosion is a process that in the last decades is affecting several coastal areas around the world. Unfortunately the Tuscany coast makes no exception. The factors responsible of this phenomenon are different: some are natural, some other are related to human activities. Usually the latter determine drastic hastening of ongoing processes, mainly because they act over temporal scales much smaller than those typical of the natural factors. In this paper, multiple topographic surveys were carried out along a 5 km long sector of coast located within the boundaries of the Migliarino – San Rossore – Massaciuccoli Regional Park in order to evaluate the evolution state of the area within a 9-months timespan (January 2016 – September 2016). The results emphasize the importance to increase the knowledge about the morphodynamics processes acting on this area based on the resulting retreat that was observed analyzing the data: in just 4 months the crest of a 9 m high dune retreated of about 6 m, which resulted in a volume loss of about 80 m3/m along the selected transect. This worrying outcome implies the need to manage this sector of coast applying a rather different approach relative to those used thus far. It is paramount to consider each sector of coast as a whole and not separately, that is in accordance with the physiographic unit rather than territorial and administrative limits. In addition, this new approach must also take care of the coastal environment in the direction orthogonal to the coastline, adding into the equation rivers and catchment areas, which are the main source of sediments feeding the beaches
Vulnerabilidade costeira do Ambiente de Restinga
No full textA zona costeira sempre exerceu uma forte atração sobre o homem, seja
pela oportunidade econômica, social ou recreativa (DE JONG et al., 2014).
Ao mesmo tempo em que são ambientes altamente valorizados em âmbito
social, são acompanhados de um alto risco a condições meteorológicas
extremas
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
Sand supply from shoreface to foredunes: aeolian transport measurements and morphological evolution of a Tuscany beach stretch (Italy)
Full text linkThe coastal dunes are a highly dynamic sedimentary environment characterized by a continuous time-space readjustment in terms of morphology, shape and dimension. This is mainly due to the periodic fluctuation of the volume of sand available and by the force of the deflation processes, which are in turn driven by the interplay among pattern of vegetation cover, surface roughness and local-regional wind regime. The aim of our research is to quantify the deflation, transport and deposition of sands in a natural coastal field dune system located in the northern coast of Tuscany, Italy. The northern part of the investigated area is characterized by stable coastline condition while southwards strong erosive processes took place since 1800 year. Sedimentological data come from a series of sand collectors spaced along transects orthogonal to the coastline from the backshore to the semi stable dune field. The collectors were constructed of PVC pipe 100 x height 10 cm, with two openings 7 cm wide and 50 cm tall arranged on opposite sides of the tube. Opening willing to windward served for sand collection, and to leeward, covered with a metal wire 60μm opening. Collectors were buried along, until the base of the free window coincide with the surface of the ground about 1,5 m. The sand trapped within each collector was sampled every two hours for three consecutive times. In laboratory sand samples were weighed and subject to grain size analysis by means of mechanical sieves. The local winds parameters and their fluctuation with the time were acquired through a Meteorological mobile station. The station is equipped with three ammeters located to three different heights from ground surface: 40, 120 and 180 cm. A wireless sensor allows the constant output of data (each 5 sec) to a device. Temperature, and relative humidity value are furnished every 30 minutes. Analysis of data has evidenced the time-space fluctuation of sand volume in the two study area (stable area and under erosion). Basing on this methodological approach the time-space fluctuation of sand volume experienced by the two study areas (stable area and under erosion) has been estimated
Development of a coastal dune vulnerability index for Mediterranean ecosystems: A useful tool for coastal managers?
Full text linkCoastal dune ecosystems have been severely degraded as a result of excessive natural resource exploitation, urbanisation, industrial growth, and worldwide tourism. Coastal management often requires the use of vulnerability indices to facilitate the decision-making process. The main objective of this study was to develop a Mediterranean dune vulnerability index (MDVI) for sandy coasts, starting from the existing dune vulnerability index (DVI) proposed by Garcia-Mora et al. (2001) related to the oceanic coasts. Given that the Mediterranean sandy coasts are quite different from the Atlantic coasts, several adjustments and integrations were introduced. Our proposed index is based on the following five main group of factors: geomorphological conditions of the dune systems (GCD), marine influence (MI), aeolian effect (AE), vegetation condition (VC), and human effect (HE), for a total of 51 variables derived (and adapted) from the bibliography or proposed for the first time in this study. For each coastal site, a total vulnerability index, ranging from 0 (very low vulnerability) to 1 (very high vulnerability), was calculated as the unweighted average of the five partial vulnerability indices. Index computation was applied to 23 coastal dune systems of two different contexts in Italy, i.e. peninsular and continental island territories representative of the W-Mediterranean Basin, in order to compare the dune systems with different geomorphology, shoreline dynamics, and human pressure. In particular, our research addressed the following two questions: (1) Which variables are the most critical for the Italian coastal systems? (2) How can the coastal dune vulnerability index be used to develop appropriate strategies of conservation and management for these ecosystems? Cluster analysis and non-metric multidimensional scaling separated the peninsular from the insular sites, both of which were characterised by low to moderate values of vulnerability (0.32 < MDVI < 0.49). The most critical factors for the coastal systems examined in this study were marine negative influence, low stabilising ability of vegetation, and human disturbance. Hence, coastal managers are encouraged to plan specific management actions such as protection of foredunes from marine factors (particularly erosion), to promote dune formation with the reintroduction of native dune builder species and to minimise human pressure where vulnerability depends on these variables
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
Multidisciplinary study of the vulnerability of coastal dune system through the use of abiotic and biotic factors
No full textDispelling 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
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