1,725,941 research outputs found
Polythermal Glaciers: a Link between GPR EM Facies and Glacial Thermal Modeling
No full textIn this paper we use the entire longitudinal (GPR)profile of the Von Postbreen polythermal glacier, acquired in the Tempelfjorden region of the Svalbard Islands to link a peculiar electromagnetic anomalous zone (AZ) to the glacial thermal behaviour possibly influenced by the bedrock shape on which the glacier is lying and by the environmental thermal parameters. We used PoLIM tool, a 2D higher-order thermo-mechanical flowband modelling algorithm trying to explain the occurrences of the AZ and the other EM facies imaged by the GPR. We discovered that the AZ corresponds to a zone where the internal Von Postbreen temperature ranges between −2 °C/ −4 °C and that the Cold/Temperate-ice transition Zone on GPR data has a good correspondence with the 0°C modeled value above a bedrock uplift and with the −2°C value in the central part of the glacier, while a mismatch occurs only close to the front. The findings of this research should be validated by applying the same approach to other glaciers at different altitudes, latitudes and with different geological background, however the obtained results seem to suggest that there is a strong and distinct correlation between GPR EM facies and thermal behaviour of polythermal glaciers
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
Monitoring saltwater intrusion in the area surrounding the Grado lagoon (NE Italy)
No full textCoastal aquifers are heavily influenced by seawater intrusion, a phenomenon exacerbated by current climate change, which is affecting the availability of freshwater for drinking and irrigation purposes. This occurrence also leads to a progressive salinization of agricultural lands, adversely affecting crop yields. Despite the importance of groundwater salinization management for coastal agriculture in the Friuli Venezia Giulia region (NE Italy), there is currently a lack of detailed study on the topic. To partly fill this gap, a first field campaign was carried out in the inland areas surrounding the Grado lagoon, as part of an ongoing PhD project focusing on the regional issue. The Grado lagoon is a low energy environment characterized by higher salinity compared to the Adriatic Sea and the nearby Marano lagoon, due to shallower depth and limited presence of freshwater tributaries. In the inland regions of the Grado lagoon, which are mainly situated below sea level and predominantly utilized for agriculture, ensuring environmental sustainability rely heavily upon effective water resource management. In order to tackle this challenge and manage the water resource effectively, it is crucial to establish a comprehensive hydrogeological model of the area. Non-invasive geophysical investigation techniques have commonly been employed for this purpose in similar contexts. In this study, Electromagnetic induction (EMI) technique has been utilized for studying saline intrusion in the subsurface, thanks to its ability to explore large areas in relatively short times, detecting depth and lateral variations in electrical conductivity which can be associated with soil salinity changes. During this campaign, more than 30 km electrical conductivity profiles were collected along the lagoon margin, highlighting electrical conductivity variations, directly linked to the presence of saltwater in the aquifers closer to the saltwater body. The data obtained from EMI surveys were validated through Electrical Resistivity Tomography profiles performed in selected location and through direct sampling of groundwater, conducted via manual boreholes drilled to varying depths relatively to the groundwater level. The material retrieved from the drillings also enabled us to obtain short stratigraphic logs, which have contributed to a better understanding of the salinity distribution in the coastal aquifers. The combined approach has demonstrated its worth by providing crucial insights into the extent of salinization in the coastal phreatic aquifers. A thorough understanding of seawater intrusion is essential for future strategic planning of water resource management and agricultural development in the study area
Deep attributes: innovative LSTM-based seismic attributes
Full text linkSeismic attributes are derived measures from seismic data that help characterize subsurface geological features and enhance the interpretation of subsurface structures: we propose to exploit the hidden layers of Long-Short Time Memory neural network predictions as possible new reflection seismic attributes. The idea is based on the inference process of a neural network, which in its hidden layers stores information related to different features embedded in the input data and which usually are not considered. Neural network applications typically ignore such intermediate steps because the main interest lies in the final output, which is considered as the exclusive exploitable feature of the process. On the contrary, here we analyse the possibility to exploit the intermediate prediction steps, hereafter referred as “Deep Attributes” because they are produced by a deep learning algorithm, to highlight features and emphasize characteristics embedded in the data but neither recognizable by traditional interpretation, nor evident with classical attributes or multi-attribute approaches. Nowadays, classical signal attributes are numerous and used for different purposes; we here propose an original strategy to calculate attributes previously never exploited, which are potentially complementary or a good alternative to the classical ones. We tested the proposed procedure on synthetic and field 2-D and 3-D reflection seismic data sets to test and demonstrate the stability, affordability and versatility of the entire approach. Furthermore, we evaluated the performance of deep attributes on a 4-D seismic dataset to assess the applicability and effectiveness for time-monitoring purposes and comparing them with the sweetness attribute
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
Economia dei trasporti e logistica economica: ricerca per l'innovazione e politiche di governance
No full textAppropriate 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
2D-3D GPR across the Mt. Pollino and Castrovillari faults (southern Calabria): driving paleo-seismology researches in a complex site to infer quaternary earthquakes.
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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