1,720,962 research outputs found
ARRAY-CGH COME ESAME DI PRIMO LIVELLO NELLA DIAGNOSI MOLECOLARE DI RITARDO MENTALE E ANOMALIE CONGENITE
Full text linkThe array-CGH technique has emerged in recent years as a powerful tool for the identification of molecular causes underlying complex phenotypes characterized by intellectual disability, autism, epilepsy, psychiatric disorders and multiple congenital anomalies. Over the past 10 years, it has become clear that the conventional cytogenetic analysis is unable to detect rearrangements less than 5-10Mb which can be responsible for these clinical phenotypes. This limit has been exceeded with array-CGH technique which has increased by 15-20% the detection rate of cryptic chromosomal imbalances (deletions or duplications).
The possibility to have a genome wide technique with a high resolution led to the proposal, in 2010, by the International Standard Cytogenomic Array (ISCA) Consortium, to use this technique as the first-line test in individuals with intellectual disabilities and congenital anomalies.
From studies with microarray technology it has become clear that there are chromosomal regions in which aberrant recombination are particularly frequent, due to the presence of segments with elevated sequence homology, that cause a high degree of genomic instability.
Moreover the use of the array-CGH showed the presence in the genome of a large number of structural variations, larger than 1Kb, defined copy number variation or CNVs, that does not always represent a direct cause of disease because they have also been identified in healthy individuals. This complexity in the interpretation of pathogenic CNVs is even more relevant in prenatal diagnosis because it leads to uncertainty in terms of prognosis for the fetal health. For this reason, despite the advantages of the technique, the array-CGH analysis in prenatal diagnosis is considered as a second-line test to be used in association to conventional cytogenetics analysis.
In this study were evaluated with array-CGH analysis, 1051 patients with mental and / or developmental disabilities, autism, multiple congenital anomalies and dimorphisms. The main purpose was to verify the presence of cryptic chromosomal rearrangements in order to demonstrate the utility of genomic microarray as first-line test for the characterization of the molecular causes underlying the phenotype of individuals.
Then the mechanisms of formation of anomalies were hypothesized by the analysis of the breakpoints, to verify the presence of regions of homology that may have predisposed to the rearrangement. So it was examined whether the mechanism of formation and the clinical significance of the identified CNVs could be related to the pattern of inheritance, the type or the size of the imbalance.
The results show that 15.8% of the patients has at least one pathological anomaly or VOUS (variant of uncertain significance) that is likely pathological, and that these are more frequently deletions and CNVs arisen de novo. It was also highlighted that both the clinical significance of CNVs and their mechanism of formation may be related to the size of the imbalance.
It was later analyzed the distribution of CNVs in different chromosomes and it was found that in some of them the density of anomalies is greater than the others.
The application of the array-CGH in a high number of patients has also allowed to estimate the sensitivity to detect mosaicism, although they have a frequency less than 1% in individuals with learning disabilities. It was observed that the technique is able to detect anomalies present in up to 10% of cells.
Finally some fetal samples of chorionic villi and amniotic fluid were analyzed to evaluate the possible use of genomic microarray in prenatal diagnosis. The small number of analyzed samples did not allow us to draw conclusions, but the difficulties in the interpretation of the clinical significance of CNVs, make it a second-line test to be used in association with standard karyotype
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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