1,721,478 research outputs found
Characterizing physical habitats in rivers using map-derived drivers of fluvial geomorphic processes
No full textLerner (D.), Schramm (W.) - Communication and change in the developing countries.
No full textSaint Marc Michèle. Lerner (D.), Schramm (W.) - Communication and change in the developing countries.. In: Revue économique, volume 19, n°2, 1968. pp. 367-369
Lerner (D.), Schramm (W.) - Communication and change in the developing countries.
No full textSaint Marc Michèle. Lerner (D.), Schramm (W.) - Communication and change in the developing countries.. In: Revue économique, volume 19, n°2, 1968. pp. 367-369
The Use of Stream Power as an Indicator of Channel Sensitivity to Erosion and Deposition Processes
Full text linkStream power is a measure of the main driving forces acting in a channel and determines a river's capacity to transport sediment and perform geomorphic work. Recent digital elevation models allow the calculation of channel gradient and consequently stream power at unprecedented spatial resolution, opening promising and novel opportunities to investigate river geomorphic processes and forms. The present paper investigates the suitability of map-derived information on total and specific stream power (SSP) to identify dominant processes within the channel (i.e. erosion, transport or deposition). SSP has been already used to identify a threshold for channel stability. This paper tests this knowledge and investigates whether or not attributes of stream power profiles are statistically correlated with distinctive field morphological forms. Two gravel bed single-thread English rivers are used as case studies, the Lune and the Wye. Available deposition and erosion features surveyed in the field from 124 different locations are used to classify channel reaches as erosion, transport or deposition dominated. Meaningful patterns emerge between the stream power attributes and the field-based channel classification. An SSP threshold, which erosion is triggered, compares favourably with the ones in the literature. Information about upstream stream power profiles helps to determine the dominant processes. The joint configuration of local and upstream stream power information uniquely classifies reaches into four classes of different sensitivity to erosion and deposition
The use of monitored natural attenuation as a cost effective technique for groundwater restoration: the case study of REXCO (UK)
No full textTheoretical background and application principles of Monitoring Natural Attenuation (MNA) contaminated
aquifers not engineered remediation methodology are presented. A detailed knowledge of hydrodinamical,
hydrochemical and microbiological processes occurring inside and , particularly, at the interfacial fringe
(the so called “corona”) of the plume is put in evidence as the key factor in assessing the natural attenuation
potential. Chemical mass balance of plume and identification of chemical “footprints” reflecting that NA is
really working are the two most important tools to evaluate the processes. As a representative case study
the Rexco plant (Mansfield, UK) is considered. A phenols plume has been almost entirely attenuated by the
natural groundwater system avoiding so the contamination of wells located downgradient; at the same time
an ammonium plume, originating at the same plant, also if strongly retarded by the finer matrix of the
aquifer, has was recalcitrant to attenuation. The presented case study underlines the importance of a
combined use of both an experimental verification and a forecasting of the plume time-space evolution by
numerical models, being the first one necessary for the calibration and the progressive tuning of the second
one
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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