1,720,960 research outputs found
Practical method for flow velocity measurements in fluvial sections
No full textRecent aims and developments in water resource policies and management have been to achieve a high level of protection in both river systems as well as in the environment by natural hazard prevention and/or reduction. In river water management, the lack of direct field measures resulting from the necessity to dedicate long periods of time and effort represents a weakness in control and forecasting procedures. This paper is in reference to a detailed series of monitoring activities performed on Alzette river, in Grand-Duchy of Luxembourg and on Lucanian Rivers in Southern Italy by applying the expeditive methodology for water discharge measurement and assessment, which allows maintaining a high quality data and results
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
Rare Co-occurrence of Beta-Thalassemia and Pseudoxanthoma elasticum: Novel Biomolecular Findings
Full text linkA number of beta-thalassemia patients, independently from the type of beta-thalassemia (β0 or β+) and blood transfusion requirements, may develop, after puberty, dermal, cardiovascular, and ocular complications associated with an ectopic mineralization phenotype similar to that observed in another rare genetic disorder, namely, Pseudoxanthoma elasticum (PXE). To date, the causes of these alterations in beta-thalassemia patients are not known, but it has been suggested that they could be the consequence of oxidative stress-driven epigenetic regulatory mechanisms producing an ABCC6 down-regulation. Since, in the last years, several genes have been associated to the ectopic mineralization phenotype, this study, for the first time, applied, on beta-thalassemia patients with ectopic mineralization phenotype, a multigene testing strategy. Selection of genes to be analyzed was done on the basis of (i) their genetic involvement in calcification diseases or (ii) their role in calcium-phosphate equilibrium. Although, due to the rarity of these conditions, a limited number of patients was analyzed, the detection of pathogenic variants represents the proof of concept that PXE and beta-thalassemia traits co-occur on a genetic basis and that, in addition to causative mutations, functional polymorphisms may further influence connective tissue manifestations. The use of a multigene-based next-generation sequencing represents a useful time- and cost-effective approach, allowing to identify sequence variants that might improve prognostic assessment and better management of these patients, especially in the current era of precision medicine aiming to identify individual optimal care based on a unique personal profile
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
Practical method for flow velocity measurements in ungauged sections
No full textThe river flow forecasting represents a crucial point to employ for improving a management policy addressed to the right use of water resources as well as for conjugating prevention and defence actions against environmental degradation. Indeed, for that the European directive 2000/60/CEE states the relevance of the monitoring and control activities as support to define the whole of protection measures to adopt for achieving the “good state” of the water body. Thus, the quantitative monitoring of rivers is an essential step for environmental purposes both for addressing middle and long term surveillance and control activities, and for civil protection purposes in terms of flood forecasting and risk mitigation. In such cases, a focal point is mainly represented by a continuous updating of flow depth/discharge ratio in each gauged section. This update relies on intense field activities not to easily carry out because of several factors mainly related to weather conditions and high costs. Thus, the aim of the present work is the development and implementation of quick and efficient sampling methods for discharge assessment in order to reduce the data acquisition time and processing maintaining a good level of accuracy and precision. This is of great interest in the chain of environmental monitoring for both gauged and ungauged river sections.
In according with ISO rules, the choice of measurement verticals and velocity points has been derived by an optimization tolerance analysis proposing sampling procedures based on a set of discrete velocity measures collected following a fixed geometric pattern and grid (verticals and points). The backbone of the proposed methodology deals with the rationale that in a river flow the large amount of the moving fluid volume (discharge) is generally concentrated in about 30% up to 50% of the whole cross section and in this area the maximum velocity usually occurs. Three main verticals (i.e., placed at 1/3, 1⁄2 and 2/3 of the total observed width) are fixed for the field measurement considering the points velocities in 30% of the area below the free surface. Thus, the assessment of maximum and average velocities is available and the entropy velocity profile can be derived. The reliability of such method has been tested to gauged river sites located along the Alzette natural channel, in Grand-Duchy of Luxembourg. The results show a good “technical” agreement among observed and estimated water discharges with errors not exceeding 25%, overall
The mineralization process of insoluble elastin fibrillar structures: Ionic environment vs degradation
No full textDespite its long half-life and physiological role, elastin undergoes irreversible changes (i.e elastolysis and/or calcification) impairing resilience of soft connective tissues. At present, it is still undefined: 1) to which extent elastin fibers have to be fragmented in order to increase their susceptibility to calcify; 2) which is the contribution of ionic environment on elastin mineralization; 3) why, in the same tissue area, mineralized coexist with non-mineralized fibers. The in vitro mineralization process was investigated on insoluble elastin, hydrolyzed or not-hydrolyzed, and incubated in different cell-free ionic environments. Mineral deposition is favored on hydrolyzed fibrillar structures due to exposure of multiple charged sites increasing the adsorption of Ca2+ that can attract phosphate and increase the local ion concentration over the point of supersaturation, representing the minimum requirement for hydroxyapatite nucleation sites. At physiological pH, the degree of elastin mineralization is influenced by hydrolysis and complexity of medium composition, since ionic species, as sodium, potassium, magnesium, in addition to calcium and phosphorus, interfere with the calcification process. These findings broaden the knowledge on the factors controlling hydroxyapatite deposition on insoluble elastin and can also explain why, in vivo, calcified and non-calcified fibers can be observed within the same tissue
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