1,721,437 research outputs found
When awareness makes the difference: diagnosing and treating the acute hepatic porphyrias
No full textEvolution and chemical yields of AGB stars: effects of low-temperature opacities
Full text linkThe studies focused on the thermally pulsing asymptotic giant branch phase experienced by low- and intermediate-mass stars are extremely important in many astrophysical contexts. In particular, a detailed computation of their chemical yields is essential for several issues, ranging from the chemical evolution of galaxies to the mechanisms behind the formation of globular clusters. Among all the uncertainties affecting the theoretical modelling of this phase, and described in the literature, it remains to be fully clarified which results are severely affected by the use of inadequate low-temperature opacities, which are in most cases calculated on the basis of the original chemical composition of the stars, and do not consider the changes in the surface chemistry due to the occurrence of the third dredge-up and hot-bottom burning. Our investigation is aimed at investigating this point. By means of full evolutionary models including a new set of molecular opacities computed specifically with the AESOPUS tool, we highlight which stellar models, among those present in the literature, need a substantial revision, mainly in relation to the predicted chemical yields. The interplay among convection, hot-bottom burning and the low-temperature opacity treatment is also discussed
Aquileia Nostra, anno LXXXV
No full textIl volume raccoglie gli scritti in onore di Luisa Bertacchi, personalità fondamentale per gli studi e le vicende aquileiesi, in veste di Direttore del Museo e degli scavi
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
Innovative methods and technologies to detect and monitor chemical substances locally or remotely with active optical technologies
No full textL’aumento del terrorismo e delle guerre asimmetriche inducono a cercare strumentazioni, know how ed informazioni che possano essere utili per rilevare ed identificare le molecole pericolose più rapidamente e lontano possibile.
Il “multiwavelenght DIAL” è una delle tecnologie ottiche più performanti per l’individuazione remota . Per tale obbiettivo è necessario un database dei fingerprint e un buon metodo di analisi che sia in grado di riconoscere una sostanza tra molte differenti che mostrano caratteristiche simili.
Un mini Lidar che sia in grado di dare un allarme precoce tutte le volte che qualcosa di strano si trovi in atmosfera è un altro elemento utile. Un allarme precoce seguito dal riconoscimento usando la più complicata tecnologia Multiwavelenght Dial sembra essere la soluzione migliore anche a confronto con i dispositivi esistenti. Allo scopo di riconoscere l’anomalia in atmosfera una tecnica di analisi multivariata è proposta.
In questa tesi nel capitolo uno vi è una descrizione delle sostanze chimiche pericolose e dei metodi di riconoscimento esistenti. Un progetto ed alcune attività sperimentali su un nuovo mini Lidar viene illustrato nel capitolo due. Un nuovo sistema ed un nuovo metodo basato sul Multiwavelenght Dial è illustrato nel capitolo tre. Spettri nella banda IR, compiuti usando un Laser a CO2, di armi chimiche, TIC e sostanze interferenti ed il set up sperimentale organizzato sono illustrati nel capitolo quattro. Questi dati sono usati, nel capitolo cinque, per testare il nostro metodo di identificazione basato sull’analisi statistica multivariata e le reti neurali, dove è descritta anche una cella multipasso progettata per aumentare le prestazioni del sistema. Il capitolo sei è dedicato ad un possibile applicazione del nostro set up sperimentale per un sensore locale. Infine le conclusioni dell’intero lavoro saranno date.Considering increasing dangerousness of terrorism and asymmetric war, it is necessary to find equipment, know-how and information that are useful in order to detect and identify dangerous molecules as quickly and far away as possible.
Multiwavelenght Dial, is one of the most powerful optical technologies for remote sensing. For this reason it is needed a “fingerprint” database and a good analysis method able to recognize a substance among many different ones.
A cheap and reliable Lidar which is able to give a warning whenever something strange is found in atmosphere could be useful as well. An early warning followed by recognition using the more complicated Multiwavelength Dial technology seems to be the best solution also compared to existing devices. To recognize the anomaly in atmosphere a multivariate statistical method is proposed.
In this thesis a review of dangerous chemical substances and detecting method is illustrated in chapter one. A project and some experimental activity on a cheap mini Lidar is presented in chapter two. A new system and a new method based on Multiwavelenght Dial is explained in chapter three. IR spectra, made using a CO2 laser source, of Chemical Weapons, Toxic Industrial Chemicals (TIC) and interfering substances and experimental set up organized are presented in chapter 4. This data will be used to test recognition and discrimination performance of our multivariate statistical analysis and neuronal network based method in chapter 5, where a multipass cell projected to improve system performance is also illustrated. Chapter 6 is devoted to a possible local sensor application of our experimental set up and finally general conclusion will be done
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
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