1,721,011 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
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
Cardiovascular risk factors and carotid stenosis predict cerebral haemodynamic impairment in Alzheimer’s Disease
No full textAbstract: Alzheimer’s Disease (AD) is the most common form of
progressive dementia among internistic patients. Many hypotheses
have been postulated for AD pathogenesis, and there is a growing but
conflicting evidence about a vascular theory (1,3). Recently, we found
a significant correlation between extracranial carotid atherosclerosis,
intracranial vascular reactivity and mini-mental state examination
(MMSE) impairment over a 12-months observation in a cohort of 442
AD patients (2).
Aims: Aim of this study was to evaluate the correlation between
intracranial vascular reactivity index (breath-holding index, BHI),
extracranial carotid atherosclerotic involvement and classical cardiovascular
risk factors, as demographic characteristics, smoking,
hypertension, diabetes and dyslipidemia in a cohort of patients
affected by clinically defined AD.
Patients and Methods: We enrolled 745 consecutive patients followed
by the dementia ward of our University Hospital (A.O.U.
Ospedali Riuniti, Ancona). Each patient underwent a standardized
interview about clinical history, neuropsycological evaluation,
extracranial echo-color Doppler ultrasound and transcranial doppler
(TCD), testing BHI for each side. We synthesized each
classical risk factor and sex into a dichotomous variable; the
number of risk factors affecting a single patient were collected into
an ordinal variable (ranging from 0 risk factors to 4 risk factors);
extracranial echo-color Doppler result was expressed into an
ordinal variable, ranging from ‘‘no stenosis’’ to ‘‘bilateral haemodynamic
stenosis’’. Only hemodynamically significant ([60% of
the internal carotid lumen) stenoses were considered. MMSE
scores, corrected for age and sex, were collected as continuous
variables. Breath-holding index, calculated by dividing the percent
increase in mean flow velocity occurring during breath-holding by
the length of time (in seconds) subjects hold their breath after a
normal inspiration, was synthesized both as a dichotomous variable
(\0.69, pathologic, [0.69, normal) (3) and as an ordinal variable
(normal, monolateral pathologic and bilateral pathologic). Statistical
analysis was conducted with two ordinal regression models,
one considering BHI as dichotomous, the other considering BHI as
ordinal. Both models included the classical risk factors, the synthetic
variable for the number of risk factors and the ordinal
variable for extracranial echo-color Doppler results. Results have
been weighted by MMSE, age and sex. Ordinal regression was
calculated with SPSS 13.0 for Windows systems. Probability of
each event was calculated as 1/[1 + (ea-bx)], being a the level
threshold and bx the factor level.
Results: The probability of a normal BHI in AD patients
decreased proportionally with the increase of the number of
vascular risk factors, from 95% in patients with no risk factor to
21% of patients with four risk factors (Fig. 1, p\0.05). Extracranial
echo-color Doppler ultrasound could also predict a
pathological BHI: the probability of a normal BHI decreased from
73% among patients without hemodynamically significant stenosis
to 21% in patients with bilateral stenosis (Fig. 2, p\0.05). Each
vascular risk factor was also associated with an increase of the
risk of developing a pathological (monolateral or bilateral) BHI
(p\0.05).
Discussion: AD is a complex disease, and its pathogenesis, still uncleared,
could be related to microvascular alterations in a favourable
genetic background. Hypertension, diabetes, smoking and dyslipidemia
have already been associated to AD and its progression (1). Both
BHI and extracranial vessels involvement can predict a worse outcome
at 12 months in MMSE, independently from specific treatment
and risk factors presence (2). BHI is a suitable index for cerebral
hemodynamics status, and its alteration could express the final pathway
of vascular derangement in AD. Classical risk factors and
extracranial haemodynamic impairment could act on intracranial
circulation initiating and maintaining the cascade of events responsible
of AD progression
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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