1,721,042 research outputs found
The fish circadian timing system: The illuminating case of light-responsive peripheral clocks [*Pagano C. first author]
No full textDysfunctions in Dopamine Systems and ADHD: Evidence From Animals and Modeling
No full textAnimal models are useful for characterizing
neural substrates of neuropsychiatric disorders.
Several models have been proposed for the
study of Attention Deficit Hyperactivity Disorder
(ADHD). The models can be divided into various
groups: (i) genetically derived hyperactivity/
inattention, (ii) animal models showing symptoms
after pharmacological intervention, and (iii)
those based on spontaneous variations in a
random population. Spontaneously hypertensive
(SHR) and Naples High Excitability (NHE) rats
show behavioral traits featuring the main
aspects of ADHD in humans but show different
changes in dopamine (DA) systems. In fact, the
enzyme tyrosine hydroxylase is hyperexpressed
in NHE rats and hypoexpressed in SHR. The DA
transporter is hyperexpressed in both lines,
although in the SHR, DAT activity is low
(reduced DA uptake). The DA levels in the
striatum and prefrontal cortex are increased in
the juvenile SHR, but are decreased in handled
young and non-handled older animals. The
mRNA of the D1 DA receptor is upregulated
in the prefrontal cortex of SHR and downregulated
in NHE. The D2 DA receptors are
likely to be hypofunctioning in SHR, although
the experimental evidence is not univocal,
whereas their mRNA is hyperexpressed in
NHE. Thus, in SHR both the mesocortical and
mesolimbic DA pathways appear to be
involved, whereas in NHE only the mesocortical
system. To understand the effects of
methylphenidate, the elective ADHD drug
treatment in humans, in a dysfunctioning DA
system, we realized a simple mathematical
model of DA regulation based on experimental
data from electrophysiological, cyclic
voltammetry, and microdialysis studies. This
model allows the estimation of a higher firing
frequency of DA neurons in SHR rats and
suggests that methylphenidate increases
attentive processes by regulating the firing rate
of DA neurons
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
Behavioural, pharmacological, morpho-functional molecular studies reveal a hyperfunctioning mesocortical dopamine system in an animal model of attention deficit and hyperactivity disorder
No full textThe Naples High- and Low-Excitability rats: selective breeding, behavioral profile, morphometry, and molecular biology of the mesocortical dopamine system
No full textAppropriate 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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