1,720,970 research outputs found
Landslide on glaciers: an example from Western Alps (Cogne - Italy)
No full textIn the warm summer of 2017, a landslide failed from the south-east side of the Col des Clochettes on the top of the underlying Trajo Glacier. The study area is at an elevation of about 3500 m a.s.l. in the Gran Paradiso Massif and can be hardly reached by walking from Cogne (Aosta Valley, NW Italy). Studies conducted by field surveys, photogrammetry (structure from motion) and satellite images analysis, integrated with the evaluation of data from meteorological stations have been used to reconstruct the phenomenon and infer its causes. The site is very complex to be studied especially due to logistic problems, therefore, measurements and observations that are common practice in other landslides are very difficult to apply here. So, many of the results achieved are not adequately supported by field studies. Anyway, the following factors could have affected the stability of the slope: i) the tectonic structure of the area, which is reflected on the morphology and on the geomechanics characteristics of the rock masses; ii) the meteorological conditions during 3 months before the main failure, resulting in an extremely high temperature compared to historical data. Moreover, the analysis of multitemporal satellite images allowed to recognize that it was not a single landslide but that the phenomenon is articulated over time in at least five failures in about 2 months. Moreover, several predisposing factors may have been playing an important role in causing the instability: the degradation of permafrost (probably affecting rock mass due to the circulation of warm air and water in the discontinuity systems), the alternance of the freeze-thaw cycles and the availability of a considerable amount of water from rainfalls and nival fusion infiltrating deeply in the rock mass. More common causes such as rains and earthquakes have been excluded
Rischi glaciali in Valle d'Aosta. Monitoraggio e ricerca applicata
No full textI fenomeni di origine glaciale rappresentano una fonte di rischio importante nelle aree
di montagna e nelle Alpi in particolare. Il rischio deriva dall’interazione tra le dinamiche
glaciali, molto attive ed in rapida evoluzione anche – ma non solo – in relazione al
cambiamento climatico, e la presenza antropica, in forte espansione nelle aree alpine
nell’ultimo secolo. I principali rischi di origine glaciale derivano dal crollo di seracchi,
dal collasso di ghiacciai temperati e dal rilascio improvviso di acqua accumulata nei
ghiacciai stessi. Il territorio valdostano, per le sue caratteristiche, è particolarmente
soggetto a tali rischi. Per questa ragione l’amministrazione regionale, tramite la Fondazione
montagna sicura, ha attuato un piano di monitoraggio specifico per il rischio
glaciale. Il piano si articola in diverse azioni, sia a livello dell’intero territorio sia per il
monitoraggio di casi specifici
Impact of Deep-seated Gravitational Slope Deformation on urban areas and large infrastructures in the Italian Western Alps
No full textDeep-seated Gravitational Slope Deformations (DsGSDs) are huge ground-deformation slow evolving phenomena, highly widespread in alpine territory. Their long-lasting evolution, with continuous deformation rate, may represents a natural hazard, able to endanger various anthropic structures and infrastructures. Until today, the development of technical and regulatory tools, aimed to effectively manage the interactions between DsGSDs and anthropic elements, has been generally lightly considered in risk management and land use planning. The definition of the type and severity of impacts on the anthropic elements, becomes increasingly important in terms of urban planning and risk management, and deserve an update in the current adopted procedures. Focusing on the Western Italian Alps, we implemented an interdisciplinary analysis, based on multi-source data, by means of geoinformatics, remote sensing and archive consultation approaches. Intersecting DsGSDs available information with the urbanized territory in a Geographic Information System environment, we obtained, despite the high data heterogeneity, an overall framework of the existing interactions. Specifically, we defined the interactions between these large phenomena and buildings, roads and rail networks, and linear infrastructures, as penstocks, waterworks or dams, also highlighing the state of activity of the inventoried phenomena. Moreover, we analysed the degree of the DsGSD impacts on the anthropic elements, detecting and classifying all the documented damages within the Italian Western Alps territory. The obtained results highlight the need for an innovative approach in DsGSDs risk assessment, both in terms of the definition of their behavior over time and of their impacts on the anthropic elements, for a more effective land use planning and a proper handling of these phenomena in the legislation framework
Integration of satellite interferometric data in civil protection strategies for landslide studies at a regional scale
Full text linkMulti-Temporal Satellite Interferometry (MTInSAR) is gradually evolving from being a tool developed by the scientific community exclusively for research purposes to a real operational technique that can meet the needs of different users involved in geohazard mitigation. This work aims at showing the innovative operational use of satellite radar interferometric products in Civil Protection Authority (CPA) practices for monitoring slow-moving landslides. We present the example of the successful ongoing monitoring system in the Valle D’Aosta Region (VAR-Northern Italy). This system exploits well-combined MTInSAR products and ground-based instruments for landslide management and mitigation strategies over the whole regional territory. Due to the critical intrinsic constraints of MTInSAR data, a robust regional satellite monitoring integrated into CPA practices requires the support of both in situ measurements and remotely sensed systems to guarantee the completeness and reliability of information. The monitoring network comprises three levels of analysis: Knowledge monitoring, Control monitoring, and Emergency monitoring. At the first monitoring level, MTInSAR data are used for the preliminary evaluation of the deformation scenario at a regional scale. At the second monitoring level, MTInSAR products support the prompt detection of trend variations of radar benchmarks displacements with bi-weekly temporal frequency to identify active critical situations where follow-up studies must be carried out. In the third monitoring level, MTInSAR data integrated with ground-based data are exploited to confirm active slow-moving deformations detected by on-site instruments. At this level, MTInSAR data are also used to carry out back analysis that cannot be performed by any other tool. From the example of the Valle D’Aosta Region integrated monitoring network, which is one of the few examples of this kind around Europe, it is evident that MTInSAR provides a great opportunity to improve monitoring capabilities within CPA activities
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
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