1,720,960 research outputs found
Perioperative complications following major vascular surgery. Correlations with preoperative clinical, electrocardiographic and echocardiographic features
No full textCardiac Comorbidities and Their Effect in Autism Spectrum Disorder
Full text linkAutism spectrum disorder (ASD) is characterised by neurodevelopmental and behavioural deficits, while having associated comorbidities, amongst which cardiac are common. ASD and congenital heart disease (CHD) are linked on a functional and genetic level. Most work focuses on CHD-related neurodevelopmental abnormalities; less so on ASD-related cardiac abnormalities. The first aim of this work is the identification of the cardiac phenotype associated with prominent genetic contributors of ASD. The second aim is the interrogation of the association between the cardiac and neuroanatomical phenotypes observed. We hypothesize the existence of cardiac abnormalities and their association to neuroanatomy in the presence of ASD-related genetic abnormalities.ASD presents high etiological and phenotypic heterogeneity. Preclinical studies allow for rigorous experimental design using numerous animal models, which together provide an approximation to the disorder. We firstly reviewed the types of animal models and phenotyping methods employed in preclinical studies, along with the most prominent treatments considered. High variability was documented. Identification of common mechanistic processes, arising from diverse genetic causes, enabling patient stratification, seems essential for future treatment development. For the purposes of this dissertation, mouse models of ASD were used, while high-frequency ultrasound biomicroscopy (UBM) and magnetic resonance imaging (3D ex-vivo structural MRI) were chosen for the cardiac and neuroanatomical phenotyping respectively.
The prevalence of cardiac comorbidities was investigated in 9 ASD-related genetic mouse models (Arid1b(+/-), Chd8(+/-), 16p11.2 (deletion), Sgsh(+/-), Sgsh(-/-), Shank3 Dexon 4-9(+/-), Shank3 Dexon 4-9(-/-), Fmr1(-/-), Vps13b(+/-)), and pooled wild-type littermates (WTs). Mutant groups (MUTs) presented small-scale alterations in cardiac structure and function. Among MUTs there were more cardiac differences, primarily in structural measures, than between MUTs and WTs, recapitulating the characteristic ASD heterogeneity.
The association of the cardiac comorbidities on neuroanatomy was interrogated for 6 of these models (Arid1b(+/-), 16p11.2 (deletion), Sgsh(+/-), Sgsh(-/-), Fmr1(-/-), Vps13b(+/-)), for which brain MRIs were obtained. Using blind source separation (BSS) analysis, we identified three mechanisms driving the heart-brain interactions. The first is the autonomic regulation of the heart by the brain, the second is the effect cardiac function has on the brain through blood flow and the supply of necessary oxygen and nutrients, and the third involves a congenital cardiac malformation impacting lower order brain functions, such as motor regulation. The second and third mechanisms were also identified in the International Mouse Phenotyping Consortium (IMPC) dataset, comprising of a different set of cardiac measures and neuroanatomical information for mouse models of the same type of genetic contributors of ASD (www.mousephenotype.org) (Dickinson et al. 2016), after performing the same analysis, supporting the generalisability of our findings.
Our results shed light on the presence and role of cardiac comorbidities in ASD. Furthermore, they demonstrate the impact of even non-lethal cardiac abnormalities on development, recapitulating already established clinical
observations in non-ASD cases. This dissertation highlights additional potential aetiologies of the observed neuroanatomical particularities in ASD, which, if validated in humans, can have an important clinical impact, in prognosis, prevention and treatment.Ph.D
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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