1,720,961 research outputs found
Tecniche idrogeofisiche per la caratterizzazione di un acquifero eterogeneo
No full textTecniche idrogeofisiche per la caratterizzazione di un acquifero eterogene
Assessment of natural background levels in potentially contaminated coastal aquifers
Full text linkThe estimation of natural background levels (NBLs) of dissolved concentrations of target chemical species in subsurface reservoirs relies on a proper assessment of the effects of forcing terms driving flow and transport processes taking place within the system and whose dynamics drive background concentration values. We propose coupling methodologies based on (a) global statistical analyses and (b) numerical modeling of system dynamics to distinguish between the impacts of different types of external forcing components influencing background concentration values. We focus on the joint application of a statistical methodology based on Component Separation and experimental/numerical modeling studies of groundwater flow and transport for the NBL estimation of selected chemical species in potentially contaminated coastal aquifers. We consider a site which is located in Calabria, Italy, and constitutes a typical example of a Mediterranean coastal aquifer which has been subject to intense industrial development. Our study is keyed to the characterization of NBLs of manganese and sulfate and is geared to the proper identification of the importance of a natural external forcing (i.e., seawater intrusion) on NBL assessment. Results from the Component Separation statistical approach are complemented by numerical simulations of the advective-dispersive processes that could influence the distribution of chemical species (i.e., sulfate) within the system. Estimated NELs for manganese are consistent with the geochemical composition of soil samples. While Component Separation ascribes the largest detected sulfate concentrations to anthropogenic sources, our numerical modeling analysis suggests that they are mainly related to the natural process of seawater intrusion. Our results indicate that the use of statistical methodologies in complex groundwater systems should be assisted by a detailed characterization of the dynamics of natural (and/or induced) processes to distinguish effective anthropogenic contamination from natural conditions and to define realistic environmental clean-up goals
Caratterizzazione di un sito sperimentale sedimentario sulla base di informazioni sedimentologiche e geofisiche
No full textSi presenta la caratterizzazione di un acquifero sedimentario eterogeneo mediante l’uso congiunto di osservazioni sedimentologiche, idrauliche e geofisiche. L’acquifero è concettualizzato con modello a continui multipli. La ricostruzione dell’architettura interna del sistema è effettuata a partire da informazioni sedimentologiche (porosità) ottenute mediante una sonda a neutroni ed attraverso una applicazione di Kriging ad indicatori multipli. La struttura variografica degli indicatori che individuano i diversi litotipi è analizzata mediante criteri formali di identificazione di modelli. La distribuzione spaziale della conducibilità idraulica è condizionata su misure piezometriche e di potenziale spontaneo, ottenute durante una lunga campagna sperimentale, svolta al Boise Hydrogeophysical Research Site, Idaho, in cui sono stati effettuati una serie di test di emungimento/iniezione con una configurazione a dipolo. I dati di carico idraulico sono ottenuti da usuali letture piezometriche e rappresentano un valore integrato sulla profondità. I segnali di potenziale spontaneo restituiscono la stima della posizione della superficie freatica. La procedura adottata consente la ricostruzione tridimensionale dell’eterogeneità del sito con un livello di dettaglio che non è stato possibile ottenere negli studi precedenti e con modesti sforzi computazionali. La robustezza dei risultati è stata analizzata utilizzando il modello calibrato per la riproduzione di risultati di test con dipolo non utilizzati nella procedura di inversione
LABORATORIO HYDROGEOSITE: PRIMI ESPERIMENTI IDROGEOFISICI
No full textLaboratorio hydrogeosite: primi esperimenti idrogeofisic
First hydrogeophysical controlled experiments in the large lab-scale Hydrogeosite Laboratory (IMAA-CNR)
No full textFirst hydrogeophysical controlled experiments in the large lab-scale Hydrogeosite Laboratory (IMAA-CNR)
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
Hydrogeophysical approach to estimate hydrogeological parameters
No full textHydrogeophysical approach to estimate hydrogeological parameter
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
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