1,721,010 research outputs found
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
Indagine conoscitiva in un macello della Toscana nei confronti della prevenzione della BSE
No full textThe European Common Market represents an important milestone for the
realisation of an European agri-food policy. Yet, it implies several troubles often related to the
abolition of the boundary veterinary controls, modifying interventions and responsibilities of
the N.S.S. In this work, we examined the outcomes of BSE tests performed on 291 bovines
older than 24 months, in a slaughterhouse of Tuscany along a period of 17 months. No
positive cases have been found. Furthermore, the percentage of animals with problems related
to clinic systemic pathologies was very low (9,62%)
A Second Order Upper Bound for the Ground State Energy of a Hard-Sphere Gas in the Gross–Pitaevskii Regime
Full text linkWe prove an upper bound for the ground state energy of a Bose gas consisting of N hard spheres with radius a/ N, moving in the three-dimensional unit torus Λ. Our estimate captures the correct asymptotics of the ground state energy, up to errors that vanish in the limit N→ ∞. The proof is based on the construction of an appropriate trial state, given by the product of a Jastrow factor (describing two-particle correlations on short scales) and of a wave function constructed through a (generalized) Bogoliubov transformation, generating orthogonal excitations of the Bose–Einstein condensate and describing correlations on large scales
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
Ground state energy of a Bose gas in the Gross-Pitaevskii regime
Full text linkWe review some rigorous estimates for the ground state energy of dilute Bose gases. We start with Dyson's upper bound, which provides the correct leading order asymptotics for hard spheres. Afterward, we discuss a rigorous version of Bogoliubov theory, which recently led to an estimate for the ground state energy in the Gross-Pitaevskii regime, valid up to second order, for particles interacting through integrable potentials. Finally, we explain how these ideas can be combined to establish a new upper bound, valid to second order, for the energy of hard spheres in the Gross-Pitaevskii limit. Here, we only sketch the main ideas; details will appear elsewhere
Ipotiroidismo subclinico nel paziente anziano: sindrome clinica o condizione parafisiologica?
No full textUn lieve deficit della funzione tiroidea o ipotiroidismo
subclinico (sHT), definito a livello biochimico
come una concentrazione di ormone stimolante la tiroide
(TSH) oltre il limite superiore del range di riferimento associato
a valori normali di T4 (FT4) e T3 (FT3) liberi,
è una condizione clinica frequente nella popolazione generale,
specie nelle donne, la cui prevalenza aumenta con
l’aumentare dell’età. Va comunque sottolineato come, con
l’invecchiamento, si assista a un progressivo aumento dei
valori medi di TSH che, secondo alcuni autori, renderebbe
necessario definire range specifici di normalità. In generale,
l’attività tiroidea potrebbe avere un legame con l’invecchiamento
per l’intimo collegamento tra metabolismo basale
e i processi catabolici (accelerati nell’invecchiamento).
L’ipotiroidismo subclinico è stato associato a iperlipidemia,
alterazioni del metabolismo glucidico, ipertensione arteriosa
sistemica e malattia cardiovascolare, così come ad alcune
condizioni neuro-psichiatriche, incluso il deterioramento
cognitivo. La correlazione tra eventi e/o mortalità cardiovascolare
e sHT non è ancora completamente chiarita e dati
apparentemente conflittuali sono stati riportati in letteratura,
soprattutto per quanto riguarda i grandi anziani (>80 anni).
I pochi e contrastanti risultati della letteratura non consentono
di delineare un chiaro ruolo dell’sHT nel processo di deterioramento delle funzioni cognitive. Di conseguenza, il
quesito clinico fondamentale nei pazienti con sHT è quello
di stabilire quando e se intraprendere la terapia ormonale
sostitutiva, anche in relazione al rischio potenziale di effetti
collaterali, particolarmente nei grandi anziani
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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