1,721,025 research outputs found
Consumi idrici di specie legnose stimati mediante tecniche di monitoraggio del flusso linfatico
No full textElectronic structure of the (111) ideal and relaxed surfaces of silicon by the chemical pseudopotential method
No full textThe electronic energy structure for the (111)ideal and relaxed surfaces of silicon is calculated by the chemical pseudopotential method. We use a minimal basis set of localized orbitals and an atomic-like crystal potential to compute the interaction parameters and include self-consistency. Results are compared with other more involved theoretical calculations with satisfactory agreement
Leaf temperature measured on peach trees growing in different climatic and soil water conditions
No full textIndividual leaf temperatures were measured using a Cyclops Compac 3 (Land Infrared Ltd, Sheffield, England) infrared thermometer on three peach orchards located in Italy, Spain and Portugal during 1997 and 1998. Temperature measurements were performed on 5 single leaves, well exposed to sunlight, in each of 4 stressed and 4 irrigated trees for each location. Diurnal trends of leaf and air temperature and vapour pressure deficit are reported for 6-8 days during stress onset and recovery, both in stressed and irrigated trees. Single leaf temperature appeared to be a good indicator of water stress but showed poor correlation with pre-dawn and midday leaf water potential. Differences between stressed and irrigated trees ranged from 1-2°C in the morning to 5-6°C in the hottest part of the day. These differences diminished rapidly after rewatering. Although simple to use in the field, IR leaf temperature appeared unreliable for water management in fruit tree crops because it is strongly influenced by climatic conditions showing pronounced variations from day to day
Electronic vacancy states in silicon by the chemical pseudopotential method
No full textThe electronic states of a neutral vacancy in Si are studied through the chemical pseudopotential method by creating a vacancy in a large crystal unit cell containing up to 54 atoms. A localized vacancy state is found in the forbidden gap and its energy is shown to be convergent with respect to the size of the cell. The density of states of the valence band is modified by the presence of the vacancy with additional peaks which give charge localization on the vacany nearest neighbour atoms
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
Deep Semantic Segmentation of Echocardiographic Images using Vision Transformers
No full textDeep learning (DL) methods have revolutionized image segmentation by providing tools to automatically identify structures within images, with high levels of accuracy. In particular, Convolutional Neural Networks (CNN), such as the U-Net and its variants, have achieved remarkable results in many segmentation tasks. Only recently, Vision Transformer (ViT)-based models have emerged and in some cases demonstrated to outperform CNNs in semantic segmentation tasks. However, transformers typically require larger amounts of data for training as compared to CNNs. This can result in a significant drawback given the time-consuming nature of collecting and annotating data, especially in a clinical setting. In particular, only a few studies involved the application of ViT networks for ultrasound image segmentation.In this study, we propose one of the earliest applications of ViT-based architectures for segmenting the left heart chambers in 2D echocardiographic images. Indeed, the identification of cardiac structures, like e.g. heart chambers, can be used to derive relevant quantitative parameters, such as atrial and ventricular volumes, the ejection fraction, etc.We trained and tested several ViT models using the publicly available CAMUS dataset, composed by cardiac image sequences from 500 patients, with the corresponding mask labels of the left ventricle and left atrium. ViT networks performances were then compared to an implementation of the U-Net. We demonstrate how, on this type of data, recent ViT variants can reach and even outperform CNNs, despite the limited data availability
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