1,721,039 research outputs found
Rilievo morfometrico per la digitalizzazione di tipi paleontologici del "Museo Geologico G. Cappellini" dell'Università di Bologna
No full textRilievo morfometrico per la digitalizzazione di tipi paleontologici del "Museo Geologico G. Cappellini" dell'Università di Bologna attraverso laser scanner a tempo di volo e triangolazione ottica
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
Agent-based modelling for wildfire behaviour prediction
No full textWildfires are increasingly affecting ecosystems worldwide with significant impacts on risk exposed human communities. This study is intended to improve and optimize decision-making processes in wildfire risk management by implementing a predictive spatially distributed model of wildfire behaviour. The proposed methodology has been applied to simulate some large and well-documented wildfire events in Umbria and Sardinia regions (Italy), under different climatic and environmental conditions. The predictive model for wildfire behaviour has been based on the Rothermel’s quasi-empirical mathematical model, which investigates propagation-driving parameters, i.e. the local geomorphometrical and meteorological parameters along with the pyrological and phenological characteristics of the local plant communities, to estimate the rate of spread of the fire. Remote sensing-derived data have been analysed along with ancillary data to assess propagation-driving parameters and their spatiotemporal variability in the pre-fire environment by applying and adapting empirical relationships well-established in literature. Satellite estimated propagation-driving parameters have been compared with information collected in the field by the State Forestry Corps and recorded by the regional annual reports on wildfire events, revealing a good predictive ability. A two-dimensional Agent-Based Model with a hexagonal grid has been then developed in order to simulate the wildland surface fire behaviour. Given the wildfire ignition point and a temporal sequence of maps of the rate of spread as inputs, the model returns a map of the simulated burnt area at a given time. The wildfire behaviour model has provided accurate predictions, up to 70% in terms of morphological matching between simulated burnt areas and respective documented historical events boundaries. Obtained results suggest the developed wildfire behaviour model could represent a promising tool in prioritizing suppression interventions by providing maps of wildfires' predictive patterns in near-real time
Optical properties of organically functionalized silicon surfaces : Uracil-like nucleobases on Si(001)
Full text linkWe predict UV reflectance anisotropy spectra (RAS) of the organically functionalized silicon (001) surface covered by pyrimidinic uracil-like nucleobases. First-principles results based on density functional theory show characteristic spectral features appearing in the UV range between 3 and 7 eV, besides the expected quench in the well-known two-minima RAS signal of clean Si(001). Nucleobase adsorption in the energetically favored “dimer bridge” configuration gives rise to a characteristic RAS line shape, common to thymine, uracil, and 5-fluorouracil. We trace back the origin of such spectral features by singling out RAS structures induced by relaxation and passivation effects on the Si surface, and those directly associated with molecular excitations. The former turn out to be the same for the three nucleobases, and are totally unaffected by molecular tilting. The sign and position of the latter RAS peaks at higher energy exhibit a moderate nucleobase dependence, and can be fully rationalized in terms of the molecular orbitals involved. The present theoretical results call for a RAS experimental study in the UV region extending up to ≃6–7 eV
Most appropriate animal models to study the efficacy of statins: a systematic review
No full textBackground: In animal models and clinical trials, statins are reported as effective in reducing cholesterol levels and lowering the risk of cardiovascular diseases. We have aggregated the findings in animal models - mice, rats and rabbits - using the technique of systematic review and meta-analysis to highlight differences in the efficacy of statins. Materials and methods: We searched Medline and Embase. After examining all eligible articles, we extracted results about total cholesterol and other blood parameters, blood pressure, myocardial infarction and survival. Weighted and standard mean difference random effects meta-analysis was used to measure overall efficacy in prespecified species, strains and subgroups. Results: We included in systematic review 161 animal studies and we analysed 120 studies, accounting for 2432 animals. Statins lowered the total cholesterol across all species, although with large differences in the effect size: -30% in rabbits, -20% in mice and -10% in rats. The reduction was larger in animals fed on a high-cholesterol diet. Statins reduced infarct volume but did not consistently reduce the blood pressure or effect the overall survival. Few studies considered strains at high risk of cardiovascular diseases or hard outcomes. Conclusions: Although statins showed substantial efficacy in animal models, few preclinical data considered conditions mimicking human pathologies for which the drugs are clinically indicated and utilized. The empirical finding that statins are more effective in lowering cholesterol derived from an external source (i.e. diet) conflicts with statin's supposed primary mechanism of action
Optical Properties of Free and Si(001)-Adsorbed Pyrimidinic Nucleobases
No full textIn this work, we predict and analyze the optical spectra of pyrimidinic uracil-like nucleobases thymine (THY), uracil (URA), and 5-fluorouracil (5-FU) and their reflection anisotropy spectra (RAS) upon adsorption on the silicon (001) surface. First-principles results based on plane-wave density functional theory show chemically sensitive features in gas phase optical absorption spectra that redshift/blueshift according to the orbitals involved in the corresponding transition. In the RAS, a characteristic lineshape is found, typical of the energetically favored “dimer bridge” configuration, and remarkably similar for all the investigated Si(001):X systems (X = THY, URA, 5-FU). We show that molecular tilting and breaking of the glide plane symmetry have a negligible effect on the optical spectra, despite their influence on the surface bandstructure. Contrarily to gas phase spectra, chemically sensitive RAS features only appear above 4.5 eV, and can be recognized as molecular contributions consistent with gas phase optical absorption results whereas substrate effects dominate at lower energies
Wildfire behaviour modelling for wildfire hazard characterization: an Earth Observation application
No full textThe study is intended as a contribution to the developement of a wildfire behaviour modelling methodology effective in wildfire hazard characterization on a local scale and providing an appropriate scientific information available in decision making processes for wildfire management. Satellite sensor technologies has been investigated in order to acquire updated and reliable input data with a suitable spatial and temporal resolution. The modelling methodology has been validated and calibrated to past events recorded in wildland fire databases of Umbria and Sardinia Regions. Afterwards, an heuristic local research method has been implemented to optimize the accuracy of the models and to estimate their predictive capacity
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