1,721,131 research outputs found
Stationary flow of of a quasi-geostrophic stratified atmosphere past finite amplitude obstacles
No full textThe stationary flow past finite amplitude bottom topography of a quasi-geostrophic atmosphere, uniform in wind and entropy stratification far from the obstacle, is studied on an f-plane. Analytic solutions for the two cases of finite slope (hemispheroid) and infinite slope (disc) mountains are discussed. The obstacles act on the flow in different ways in the two cases. In the case of finite slope the obstacle influences the model atmosphere through the lifting of isentropic surfaces near the lower boundary. The consequent shrinking of vortex tubes produces anti-cyclonic vorticity over the obstacle and, possibly, Taylor column formation, in agreement with previous results in the literature.
In the case of an infinite slope mountain a pronounced diffluence in the horizontal streamlines is produced near the obstacle. The total circulation, again associated with the lifting of isentropic surfaces, has to be prescribed in this case for the problem to be completely determined. However, the total disturbance does not vanish when the volume of the obstacle goes to zero, provided that its cross section remains finite. The implications for numerical modelling are discussed
Verification of BOLAM precipitation forecasts for hydrological purposes using high density raingauge monitoring in the southern Alps
No full textBaja Sardinia, 1-3 October 200
TELLUS. Ground deformations and their effects in the near-Earth space
No full textThis report will describe the activities carried out by the TELLUS team during 2004. They are continuing those concerning ground aseismic creep strain events, observed by the TELLUS tilt network; the ESPERIA space mission project planned and designed for studying Earth near-Earth space interactions; the construction of the particle detector ARINA to be installed on board the Russian satellite RESURS-DK1, which launch is scheduled for next autumn 2005 within the PAMELA mission. ARINA is part of the ESPERIA payload, another one being the LAZIO-EGLE magnetic andparticle instruments to be tested in space on board the InternationalSpace Station and used for collecting particle and magnetic data. Thesetwo instruments have been built during 2004 within a collaborationbetween the Universities Roma Tre, Perugia and Roma Tor Vergata, andrelated INFN branches, with the Lazio Region and Polytechnic of Moscow(MEPhI). LAZIO-EGLE thermal, vibration and electromagnetic emission testshave been performed in laboratory both in Italy and in Russia. Launch isscheduled for February 2005. During 2003, on the basis of an ITT of theEuropean Space Agency (ESA), the TELLUS team also submitted assub-contractor (the prime one being Alenia-Laben S.p.A.) the ARETUSAproposal for a General Study with title "Techniques and SpaceborneConcepts for the Study of Earth-Quake Precursors and Analysis ofAssociated Atmospheric Effects". Both these two activities concerning theARETUSA proposal and the construction of the EGLE space magnetometer willbe described in the present annual report
The action of high and steep mountains on baroclinic instability and Alpine cyclogenesis
No full textThe modification induced on unstable baroclinic waves by high and steep bottom obstacles of limited horizontal extent is studied in some, mathematically tractable, limiting cases (obstacles with vertical lateral walls blocking the horizontal motion of the fluid). The model atmosphere is assumed quasi-geostrophic and the stability problem is dealt with in the two-level approximation. The results of such analysis show that the action of the obstacle can extend to the entire baroclinic wave unless strongly non-geostrophic effects, relaxing the “stiffness” of the quasi-geostrophic flow near the obstacle, are postulated. The weaknesses of this representation with respect to the problem of Alpine lee cyclogenesis are discussed
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
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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