1,720,980 research outputs found
On the sensitivity of long-term magnetotelluric monitoring in Southern Italy and source-dependent robust single station transfer function variability
No full textSince 2007, a permanent magnetotelluric (MT) monitoring station has been working in the seismic area of the Agri Valley (Basilicata region, southern Italy) in order to investigate the stability of the MT transfer function. The station was installed in a rural area near the supposed seismogenic fault of the strong earthquake (Mw = 6.9) that struck the Agri Valley in 1857. Analysing about 4 yr of MT data characterized by a low seismic activity, the long-term systematic variations of robust single station MT transfer function estimates were observed in two different sounding period ranges. First, a significant seasonal component of variability for short periods was noted; these short periods were up to 16 s and were linked to variations in wetting/drying of soil moisture in the shallower layers. Second, a connection between the monitored estimates and global geomagnetic activity, Ap index, was found, particularly in the [20–100 s] period range. Analysing remote reference results and tipper estimates in shorter monitoring window, it was shown that such effect cannot be explained by a local or incoherent noise, and a large-scale coherent source should be claimed. We show that this effect is subtle because it produces smooth estimates, satisfying the dispersion relationship between apparent resistivity and phase, with small error bars. As the global geomagnetic activity level increases, robust estimators, like the median value, can be considered as a representative of the estimates due to the natural source, and they tend to stabilize when the Ap index approaches 10. It is also worth noting that our monitored time window includes the recent global minimum of solar activity which occurred in 2009, thus enhancing the estimate dependence on the Ap index
Geoelectrical resistivity variations and lithological composition in coastal gypsum rocks: A case study from the Lesina Marina area (Apulia, southern Italy)
Full text linkThe Lesina Marina village (Apulia, southern Italy) lies on an exotic rocky body basically composed of Triassic gypsum surrounded and covered by thin Quaternary sandy deposits. During the last two decades instability phenomena connected to gypsum dissolution and cover suffusion sinkholes occurred mainly along the Acquarotta canal and in the urbanized area. In this study, electrical resistivity tomographies, field and petrographic observations have been carried out just ca. 300 m to the South of the residential area. The East-West striking geoelectrical profile has a length of 1900 m, intercepts two boreholes and crosscuts the Acquarotta canal. Close to the boreholes, higher resolution geoelectrical profiles, both perpendicular and parallel to the former, were performed. The two boreholes highlight the presence, from the top to the bottom, of Quaternary sandy deposits, coarse grained gypsum and layered finer grained gypsum. In correspondence, electrical resistivities are very low for the wet sandy deposits (up to 5 Ω·m), increase for coarse grained gypsum (20-120 Ω·m) and reach the maximum values for the layered finer grained gypsum (greater than 300 Ω·m). The relationship between the electrical resistivity and the lithological composition of the studied rocks is strongly controlled by their fracturing and water saturation degree. Thus considering, the main geological features here recovered are the impermeable bedrock and the above rocky body involved by mineral transformations and karstification phenomena. Additionally, the anhydrite/gypsum transformation and the gypsum dissolution are related to the groundwater circulation and localized within massive coarse grained gypsum rocks. Therefore, the hazard related to karst processes involves both an area and a depth greater than those considered up to now
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
New evidence in theory of mind deficits in subjects with chronic schizophrenia and first episode: correlation with symptoms, neurocognition and social function
No full textAim. Currently substantial evidence exists about Theory of Mind (TOM) impairment in subjects affected by chronic and first episode schizophrenia. In particular, in order to enhance the validity of our construct, we used in this study classical false beliefs tasks and advanced theory of mind tasks, together with the application of structural equation model, in order to examine whether we are using ToM tasks with good psychometric properties. The main goal of the present study was to examine ToM deficits in a large sample including subjects suffering from chronic schizophrenia, first episode of schizophrenia and normal controls, by observing in the same task the relationship with symptomatological gravity, neurocognition and social function. Materials and methods. A sample of 178 patients with chronic schizophrenia, a sample of 49 subjects with a first episode of psychosis and 484 healthy controls participated to this study. Measures of social cognition included task of false belief and advanced theory of mind task. Results. No significant differences were found on ToM tasks between subjects affected by chronic and first episode schizophrenia. Social cognition showed in both groups a strong correlation with negative symptoms and social function, but did not evidence any relationship with neurocognition. Conclusion. ToM deficits exist in subjects suffering from chronic and first episode schizophrenia. These impairments do not seem to be a consequence of illness condition, they are likely to be state-independent and appear to be the most important cognitive mediator of social functioning in both groups.Scopo. Attualmente, esistono numerose evidenze circa la compromissione della Teoria della Mente (ToM) in
soggetti affetti da schizofrenia cronica e al primo episodio. L’obiettivo del presente studio è stato quello di esaminare se la
ToM, cioè la capacità di comprendere lo stato mentale altrui, possa mediare gli effetti di altre variabili, quali la neuro-cognizione
e il funzionamento sociale e di comunità come la frequenza di contatti sociali e l’abilità di relazionarci con gli altri. Per
migliorare la validità del nostro costrutto, abbiamo utilizzato in questo studio compiti di falsa credenza e di ToM, insieme con
l’applicazione del modello di equazione strutturale, per poter esaminare la consistenza dei compiti ToM con buone proprietà
psicometriche. Materiali e metodi. Hanno partecipato a questo studio un campione di 178 pazienti con schizofrenia cronica,
un campione di 49 soggetti con un primo episodio di psicosi e 484 controlli sani. Sono stati utilizzati compiti di cognizione
sociale: compiti di falsa credenza e di ToM. Risultati. Non sono state riscontrate differenze significative nei compiti di ToM
tra i soggetti affetti da schizofrenia cronica e i soggetti con primo episodio psicotico. Infatti, tutti i pazienti hanno mostrato
una riduzione delle prestazioni ToM rispetto al gruppo di controllo. È stata riscontrata inoltre una forte correlazione tra impoverimento
della cognizione sociale e sintomi negativi e funzionamento sociale in entrambi i gruppi ma non è stato evidenziato
alcun rapporto con la neuro-cognizione. Conclusione. Sia i soggetti al primo episodio psicotico, sia i soggetti con schizofrenia
cronica soffrono di deficit di ToM. Questi disturbi non sembrano essere una conseguenza della condizione di malattia,
ma dallo stato della malattia. I nostri risultati suggeriscono che la misura di ToM rappresenta il più importante mediatore
cognitivo di funzionamento sociale in entrambi i gruppi e questo sottolinea l’importanza di utilizzare strumenti preziosi
nella pratica clinica e misure più precise per la rilevazione del disturb
Fluid conduits and shallow-reservoir structure defined by geoelectrical tomography at the Nirano Salse (Italy)
Full text linkMud volcanoes are fluid escape structures allowing for surface venting of hydrocarbons (mostly gas but also liquid condensates and oils) and water–sediment slurries. For a better understanding of mud volcano dynamics, the characterization of the fluid dynamics within mud volcano conduits; the presence, extent, and depth of the fluid reservoirs; and the connection among aquifers, conduits, and mud reservoirs play a key role. To this aim, we performed a geoelectricalsurvey in the Nirano Salse Regional Nature Reserve, located at the edge of the northern Apennines (Fiorano Modenese, Italy), an area characterized by several active mud fluid vents. This study, for the first time, images the resistivity structure of the subsoil along two perpendicular cross sections down to a depth of 250 m. The electrical models show a clear difference between the northern and southern sectors of the area, where the latter hosts the main discontinuities. Shallow reservoirs, where fluid muds accumulate, are spatially associated with the main fault/fracture controlling the migration routes associated with surface venting and converge at depth towards a common clayey horizon. There is no evidence of a shallow mud caldera below the Nirano area. These findings represent a step forward in the comprehension of the Nirano Salse plumbing system and in pinpointing local site hazards, which promotes safer tourist access to the area along restricted routes
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
A New Robust Algorithm for Fault-Plane Parameters Identification: The 2009 L’Aquila (Central Italy) Seismic Sequence Case
No full textThe study of the hypocenter distribution of seismic events related to fault structures is a crucial topic since it is linked to the geological features and to the dynamics of an investigated area. The hypocenter spatial distribution of earthquakes is used in a novel algorithmic method to clusterize earthquakes to accurately identify the strike and the dip parameters of seismogenic faults. Our algorithm works as a fast and efficient explorer in a five-dimensional space (x, y, z, τ, ϕ). It randomly selects several seismic events (pivots) and counts in all angular directions, for each pivot, how many hypocenters can be included in a prefixed volume (two dimensions larger than the third). The result is a volume that contains the maximum number of earthquakes occurring within a minimum distance from a flat area corresponding to the searched fault. With this volume is associated a hypocenter occurrence density angular diagram and a likelihood function. The likelihood function is useful to individuate the best value of the fault thickness and to test the hypothesis of fault flatness. Our algorithm was tested on simulated data and then successfully applied to the real case of the 2009 Mw6.1 L’Aquila (Central Italy) seismic sequence
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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