1,721,029 research outputs found
Hydric precipitation as joint statistical process: dry or wet day and amount of water
No full textThe long time series of daily hydric precipitations in Modena, Italy, allows homogeneity tests which do not involve the assumption of particular models. The tests show that the number of dry days which have just preceded any wet day and the amount of precipitated water are independent. This result, which is likely to be valid for the Po Valley, implies that the hydric precipitation considered as a joint process can be factorized into two independent processes. The first concerns the probability that the particular day considered is dry or wet; the second concerns the probability of a certain amount of precipitated water in that wet day. The probabilities of each process have been often studied in the literature, whereas studies on the joint process are absent. È stata analizzata la lunga serie temporale di precipitazioni idriche registrata dal 1830 a Modena, Italia, al fine di verificare se la quantità di acqua precipitata ed il numero di giorni secchi precedenti il giorno piovoso possano considerarsi variabili statistiche indipendenti. Le variabili sono risultate indipendenti. Ciò permette di semplificare il processo considerato bivariato, scomponendolo nel prodotto di due processi indipendenti. Il primo relativo alla probabilità che un certo giorno sia secco o piovoso ed il secondo relativo alla probabilità di una certa quantità di acqua precipitata in quel giorno piovoso. L'indipendenza consente di utilizzare i risultati di studi precedenti nei quali sono stati analizzati soltanto i dati sulle quantità di precipitazione oppure i dati sui numeri di giorni secchi consecutivi. Проводится анализ длинной временной последовательности выпадения осадков в Модене (Италия), который не включает никаких предположений конкретных моделей. Проведенный анализ показывает, что число сухих дней, которым предшествовал влажный день, и количество выпавших осадков можно рассматривать как независимые статистические переменные. Этот результат, по-видимому, справедлив для всей долины По. Полученный результат предполагает, что рассматриваемое выпадение осадков, как объединенный процесс, может быть факторизован в виде двух независимых продессов. Первый множитель описывает вероятность того, что рассматриваемый конкретный день является сухим или влажным; второй множитель описывает вероятность выпадения определенного количества осадков в этот влажный день. Вероятность каждого процесса довольно часто рассматривалась в литературе, однако исследования объединенного процесса отсутсвуют
Confined Diffusion
No full textAn equation for the unidimensional confined diffusion is proposed. The equation coincides with the well-known homogeneous equation except the presence of a source term. This term which has the form of a dipole distribution is located on a moving front which sharply separates two distinct regions. In the first region (from the boundary up to the front) the confined solution coincides with a suitable solution of the homogeneous equation; in the second region (besides the front) it vanishes. The source term, moreover, switches off the diffusing flux at the front. The sharp confinement allows to relax the original boundary conditions of the homogeneous equation. Precisely, to the function depending on the time at the boundary, another arbitrary function depending on the space at the initial time is added. This new function (provided not vanishing) allows to obtain in general an acceptable evolution of the front and does not prevent the validity of the conservation law: flux at the boundary is equal to the time variation of the diffusing quantity contained between the boundary and the front. By a suitable choice of this new function, so that it results to be connected to the other boundary condition (that depending on time) it is possible to arrive at an evolution of the front such as: lÖ{4Kt}\lambda \sqrt {4Kt} , where λ,K, corresponding, respectively, to a dimensionless parameter and diffusivity, depend on the medium. Under such simplifying assumption, it is possible to obtain an analytical expression for the confined solution. This solution, evaluated in a point of the space, arrives asymptotically at the same value reached by the solution of the homogeneous equation
POSSIBLE USE OF PIXE IN THE BIOGEOCHEMICAL CYCLES OF HEAVY ELEMENTS
No full textPIXE is suited for determination of abundances of heavy elements in nearly all the phases of the biogeochemical cycles involving water and atmosphere
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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