1,720,974 research outputs found
Caratterizzazione dello strato limite planetario con diversi strumenti di telerilevamento
No full textL'altezza di mescolamento, definita come la quota dello strato adiacente alla superficie
entro il quale gli inquinanti ed i costituenti atmosferici vengono rimescolati da processi
turbolenti, è uno dei parametri chiave per la caratterizzazione della bassa atmosfera, il
monitoraggio ambientale e le previsioni meteorologiche a breve scala.
Nel seminario verranno illustrati e discussi confronti tra diverse stime di questa
grandezza, ottenute mediante un ceilometer CL31 della Vaisala, un sodar doppler a tre
assi e un lidar elastico automatico, specificamente progettato e costruito per lo studio
della bassa atmosfera ( da circa 60 m fino alla torpopausa).
I due set di dati presi in considerazione, entrambi acquisiti in ambienti costiero,
hanno inoltre permesso di evidenziare l'evoluzione dello strato durante lo sviluppo della
circolazione locale di brezza, e di caratterizzare la forza ed il flusso di quest'ultima
mediante semplici relazioni di scala
Fractional calculus approach to the acoustic wave propagation with space-dependent sound speed
No full text
An application of Wright functions to the photon propagation
No full textIn a previous note a generalized Beer's law was discussed in relation to the space-fractional Poisson process to explain possible deviations from the exponential extinction law in spatially correlated media. Here a different point of view will be developed, applying a Wright type function to describe the probability of photon transmission in random media. We find the analytic form of the photon mean-free-path (MFP) related to such Wright law of extinction. We also give an estimate of the deviation from an exponential law, showing the utility of our approach and discussing a comparison with the predictions given by the classical Beer's law in uniform media. (c) 2013 Elsevier Ltd. All rights reserved
Sensitivity of near-surface meteorology to PBL schemes in WRF simulations in a port-industrial area with complex terrain
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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
Aerosol optical characteristics in the urban area of Rome, Italy, and their impact on the UV index
Full text linkThe aerosol optical characteristics in the urban area of Rome were retrieved over a period of 7 years from March to September 2010–2016. The impact of aerosol single scattering albedo (SSA), optical depth (AOD), estimated at 400 nm, and Ångström exponent on the ultraviolet (UV) index has been analyzed. Aerosol optical properties are provided by a PREDE-POM sun-sky radiometer of the ESR/SKYNET network and the UV index values were retrieved by a Brewer spectrophotometer both located in Rome. Chemical characterization of urban PM10 (particulate matter 10 micrometers or less in diameter) samples, collected during the URBan Sustainability Related to Observed and Monitored Aerosol (URBS ROMA) intensive filed campaign held in summer 2011 in the same site, was performed. PM macro-components were grouped in order to evaluate the contribution of the main macro-sources (SOIL, SEA, SECONDARY INORGANIC, ORGANICS and TRAFFIC) and the analysis of the modulation of their concentration was found to strongly affects the absorption capability of the atmosphere over Rome. The surface forcing efficiency, provided by the decreasing trend of UV index with AOD, which is the primary parameter affecting the surface irradiance, was found very significant, probably masking the dependence of UV index on SSA and Ångström exponents. Moreover it was found greater for larger particles and with a more pronounced slope at the smaller solar zenith angle. In Rome large particles are generally less absorbing since related to the presence of SOIL and SEA components in the atmosphere. The former contribution was found much higher in summer months because of the numerous episodes of Saharan dust transport
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
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