1,721,032 research outputs found
Variabilità e cambiamenti climatici in Italia nel corso degli ultimi due secoli
No full textNell’articolo viene presentato un quadro sintetico della variabilità e dei cambiamenti climatici occorsi in Italia
negli ultimi due secoli, sulla base degli andamenti evidenziati da un nuovo database di serie secolari di dati
termometrici e pluviometrici relativi a circa 100 stazioni di osservazione. Le serie sono state sottoposte ad un
dettagliato controllo di qualità e ad un’estensiva omogeneizzazione e poi utilizzate per ricavare una serie
media per tutto il Paese. L’analisi di questa serie evidenzia come in Italia, nel corso degli ultimi 200 anni, la
temperatura dell’aria sia cresciuta di circa 1 °C per secolo. Contemporaneamente si è osservato un decremento
delle precipitazioni, anche se di lieve entità e spesso poco significativo dal punto di vista statistico
Global warming, analisi delle serie storiche italiane
No full textRicostruire l’andamento del clima sulla base dei dati storici non è impresa facile. Le serie storiche sono spesso affette
da errori o disomogeneità talmente rilevanti da non fornire informazioni univoche. Per migliorare il grado di
conoscenza sul cambiamento climatico in Italia è stato necessario mettere a punto una metodologia di analisi
adeguata individuando aree con le stesse caratteristiche climatiche e con un sufficiente numero di stazioni. Per
quanto riguarda le temperature si osserva una crescita uniforme nelle diverse regioni climatiche italiane, con un
trend dell’ordine di un grado per secolo, mentre le precipitazioni sono generalmente in diminuzione
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
Statistics of the seasonal cycle of the 1951-2000 surface temperature records in Italy
Full text linkWe present an analysis of seasonal cycle of the last 50 years of records of surface temperature in Italy. We consider two data sets which synthesize the surface temperature fields of Northern and Southern Italy. Such data sets consist of records of daily maximum and minimum temperature. We compute the best estimate of the seasonal cycle of the variables considered by adopting the cyclograms' technique. We observe that in general the minimum temperature cycle lags behind the maximum temperature cycle, and that the cycles of the Southern Italy temperatures records lag behind the corresponding cycles referring to Northern Italy. All seasonal cycles lag considerably behind the solar cycle. The amplitude and phase of the seasonal cycles do not show any statistically significant trend in the time interval considere
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
Extreme summer temperatures in Western Europe
Full text linkWe discuss the evolution of summer temperature extremes over Western Europe
during 1961–2004 in the context of current climate warming. Using a parametric
approach, we investigate the role of properties and changes in probability
density functions of daily temperatures in modifying the frequency of severe,
isolated events. In this perspective, the recent intensification of extremely
warm events over Europe turns out to be well consistent with a pure, nonuniform
shift of mean values, with no room for conjectures about increasing temperature
variability
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