1,721,641 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
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
Immunolocalization of peroxisome proliferator-activated receptors and retinoid X receptors in the adult rat CNS
No full textPeroxisome proliferator-activated and retinoid X
receptors (PPARs and RXRs) are transcription factors belonging
to the steroid hormone receptor superfamily. Upon
activation by their ligands, PPARs and RXRs bind to their
target genes as heterodimers. Ligands of these receptors
include lipophylic molecules, such as retinoids, fatty acids
and eicosanoids, the importance of which in the metabolism
and functioning of the nervous tissue is well documented.
The immunohistochemical distribution of PPARs and
RXRs in the CNS of the adult rat was studied by means of a
sensitive biotinyl-tyramide method. All PPAR (, / and )
and RXR (, and ) isotypes were detected and found to
exhibit specific patterns of localization in the different areas
of the brain and spinal cord. The presence of the nuclear
receptors was observed in both neuronal and glial cells.
While PPAR / and RXR showed a widespread distribution,
and isotypes exhibited a more restricted pattern of
expression. The frontal cortex, basal ganglia, reticular formation,
some cranial nerve nuclei, deep cerebellar nuclei, and
cerebellar Golgi cells appeared rather rich in all studied receptors.
Based on our data, we suggest that in the adult CNS,
PPARs and RXRs, besides playing roles common to many
other tissues, may have specific functions in regulating the
expression of genes involved in neurotransmission, and
therefore play roles in complex processes, such as aging,
neurodegeneration, learning and memory
Interleukin-1 producing plasma cells in chronic active liver diseases and in kidney and liver grafts
No full textImmunocytochemical localization of acyl-CoA oxidase in the rat central nervous system
No full textPeroxisomal β-oxidation, consisting of four steps catalysed by an acyl-CoA oxidase, a multifunctional protein and a thiolase, is
responsible for the shortening of a variety of lipid compounds. The first reaction of this pathway is catalysed by a FAD-containing
acyl-CoA oxidase, three isotypes of which have been so far recognised. Among these, straight-chain acyl-CoA oxidase (ACOX)
acts on long and very long chain fatty acids, prostaglandins and some xenobiotics.We investigatedACOXlocalisation by means
of a sensitive, tyramide based, immunocytochemical technique, thus obtaining a complete distribution atlas of the enzyme in
adult rat CNS. Granular immunoreaction product was found in the cytoplasm of neuronal and glial cells, both in the perikarya
and in the cell processes. ACOX immunoreactive neurons were present to variable extent, in either forebrain or hindbrain
areas. Specifically, the strongest signal was detected in the pallidum, septum, red nucleus, reticular formation, nuclei of the
cranial nerves, and motoneurons of the spinal cord.We then compared the ACOX immunoreactivity pattern with our previous
distribution maps of other peroxisomal enzymes in the adult rat brain. While ACOX appeared to colocalise with catalase in the
majority of cerebral regions, some differences with respect to D-amino acid oxidase were noted. These observations support
the hypothesis of heterogeneous peroxisomal populations in the nervous tissue. The wide distribution of the enzyme in the
brain is consistent with the severe and generalised neurological alterations characterising the peroxisomal disorder caused by
ACOX deficiency (pseudo-neonatal adrenoleukodystrophy)
Oxidative stress and antioxidant response in the frontal cortex of demented and non-demented individuals with Alzheimer’s neuropathology. Proceedings of the 63rd Congress of the Italian Embryological Group (GEI)
No full textImmunocytochemical localization of catalase in the central nervous system of the rat
No full textCatalase is a marker for peroxisomes, which are ubiquitous cytoplasmic organelles. Although the distribution and features of peroxisomes are well known in liver and kidney, these
organelles have been rarely studied in neural tissues. Catalase is an important scavenging enzyme against reactive oxygen
species, as it removes H202 produced during metabolic
processes. Reactive oxygen species are involved in a number of brain lesions and in brain aging. We investigated the distribution of catalase in rat central nervous system by means of a newly developed immunocytochemical procedure for signal enhancement, using an affinity-purified polyclonal
antiserum. The data show that catalase immunoreactivity
is present in all neural cells, both neuronal and glial, albeit at different concentrations. Among glial cells, ependymal cells and tanycytes of the third ventride and the median eminence show the most intense immunoreaction; positivity is also found in oligodendrocytes and astrocytes. In general, neurons in the brainstem are relatively more immunoreactive
than those in the forebrain although, within these respective brain regions, there are areas with low and high staining intensity. Moreover, within the same area, certain types of neurons appear more immunoreactive than others. The cell bodies in the septal nudei, pallidum, reticular thalamic nucleus, mesencephalic nucleus of the trigeminal nerve, Deiter’s nudeus, locus ceruleus, cranial and spinal motor nudei, and the Golgi cells of the cerebellar cortex are among the most densely stained neurons. Catalase immunoreactivity of the cell bodies, which presumably is proportional to catalase content, appears to be only partially correlated with cell size or type of neurotransmitter used in the nerve endings; it is likely that other unknown parameters regulate the abundance of the enzyme. In many cases, highly immunoreactive cells correspond to neurons known to be resistant to
ischemia-reperfusion injury, whereas weakly stained cells
correspond to neurons that are more susceptible to ischemic damage. The amount of catalase may be critical for a protective effect against oxidative stress under pathological conditions, such as ischemia-reperfusion injury
In search for novel strategies towards neuroprotection and neuroregeneration: is PPARα a promising therapeutic target?
No full text- …
