1,721,349 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
Dobutamine stress echocardiography for children with acquired and congenital cardiac diseases
No full textpublished_or_final_versionabstracttocPaediatrics and Adolescent MedicineDoctoralDoctor of Philosoph
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
Novel echocardiographic interrogation of cardiovascular performance in long-term survivors of childhood cancers
No full textWhile incorporation of anthracyclines into chemotherapy protocols has
significantly improved survival of paediatric cancer patients, their long-term
cardiotoxic side effects are of concern. Deterioration of the commonly measured
left ventricular (LV) ejection fraction (EF) at a resting state is nonetheless
regarded as a late manifestation of cardiotoxicity. Important gaps, hence, exist
with regard to cardiovascular monitoring in the long-term. While hitherto not
been reported in survivors, advances in echocardiography including evaluation of
myocardial stiffness using diastolic wall strain (DWS), myocardial strain imaging
of LV, left atrial (LA), and right ventricular (RV), and exercise-stressed
assessment of ventricular functional reserve and arterial function, may unveil
early treatment-related alterations in cardiovascular function. The central
hypothesis of this thesis is that novel echocardiographic modalities may help to
unveil subclinical impairment of cardiovascular performance in long-term
survivors of childhood cancers.
Anthracycline-treated survivors of childhood malignancies aged 15 and
above who had been off treatment for at least 5 years were recruited from Hong
Kong. The demographic and echocardiographic findings were compared with
those of healthy aged-matched control subjects. The findings of the five studies
included in this thesis are described below. Survivors, despite having normal LV
ejection fraction, had significantly lower LV DWS and greater LV calibrated
integrated backscatter (cIB). Increased DWS was associated with greater LV cIB
and impaired LV early diastolic deformation, while greater LV cIB was
associated with impaired LV diastolic and torsional deformation. With regard to
two-(2D) and three-(3D) myocardial strain imaging, LV mechanics were similar
between female and male survivors, notwithstanding the worse LV myocardial
deformation in survivors of both sex genders compared with sex-specific controls.
Amongst all 2D and 3D strain parameters, 3D global longitudinal strain has the
greatest area under the curve, implicating its sensitivity in the detection of
subclinical cardiotoxicity in survivors. For LA mechanics, survivors had
significantly lower peak negative LA strain and greater LA cIB than controls,
coupled with lower LV shortening fraction, EF, mitral annular late diastolic
velocity. Left atrial cIB further correlated positively with LV cIB. Exercise stress
revealed blunting of the LV force-frequency relationship (FFR) and impairment
of LV and RV systolic function reserve and LV diastolic functional reserve in
survivors. Multivariate analysis revealed survivor status and baseline LV
myocardial isovolumic acceleration as significant determinants of LV FFR. For
arterial interrogation, arterial dysfunction including greater survivors had
significantly greater carotid intima-media thickness and stiffness index, and
higher central systolic blood pressure, and radial augmentation indices at rest and greater percentage increase in carotid stiffness at submaximal exercise than
controls. Importantly, a steeper slope of increase in both carotid intima-media
thickness and exercise-induced changes in carotid arterial stiffness with age in
survivors implicate the possibility of accelerated vascular ageing among survivors.
To conclude, these findings suggests increased LV myocardial stiffness,
impaired LV, RV, and LA mechanics, impaired LV and RV functional reserves,
and arterial dysfunction at rest and during exercise in anthracycline-treated
survivors of childhood cancers. These impairments provide new perspectives on
the current and future cardiovascular assessment in long-term paediatric cancer
survivors.published_or_final_versionPaediatrics and Adolescent MedicineDoctoralDoctor of Philosoph
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
Establishment of an in vitro second heart field platform with human induced pluripotent stem cells
No full textHuman induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) can be readily generated from human induced pluripotent stem cells via temporal modulation of canonical Wnt pathway with chemical means. Resulting hiPSC-CMs harbour structural, functional and electrophysiological properties of native human embryonic ventricular cardiomyocytes. Attempts to advance the hiPSC-CM phenotype beyond the embryonic stage and as a biological model for the native human adult ventricle has only been met with limited success due to the extensive structural development and remodelling of cardiomyocytes during gestation, in which we have a rudimentary understanding of the molecular processes underlying such cellular changes. Furthermore, it is still unknown which anatomical or temporal stage of the in vivo human heart hiPSC-CMs correspond to in its current stage. The in vivo heart is derived from two distinct cell populations derived from the lateral plate mesoderm (LPM), which are the first and second heart field (SHF). Transient expression of markers indicative of both progenitor populations has been identified in in vitro cardiac differentiation, but a distinct cardiac progenitor nor its specification trajectory has yet to be identified.
In this study, I utilized single-cell RNA sequencing (scRNA-seq) on different stages of in vitro cardiac specification and identified a multipotent SHF progenitor with the propensity to specify into cardiomyocyte, cardiac mesenchymal and endothelial lineage. Apelin receptor (APLNR) was identified as a surface marker for multipotent SHF progenitors and isolated APLNR+ cells were enriched for SHF markers and culturing of progenitors results in autonomous specification into predominantly cardiomyocyte with cardiac mesenchyme lineages. Consecutive RNA sequencing of APLNR+ SHF progenitors at 0, 24, 48 and 72 hours post-isolation have revealed a differentiation trajectory analogous with in vivo SHF sub-specification to the anterior heart field and further specification into right ventricular lineage cardiomyocytes. Furthermore, an isolated culture of APLNR+ in vitro SHF progenitors has led to the expression of sarcomeric isoforms and cardiac transcription factors cardiomyocytes crucial for ventricular morphogenesis but absent from conventional in vitro cardiac differentiation. Combined analysis of scRNA-seq and RNA sequencing results has suggested and demonstrated the paracrine effect of canonical notch pathway mediated by JAG1-NOTCH2 interaction in promoting the proliferation of the cardiomyocyte lineage APLNR+ in vitro SHF progenitors. Inhibition of canonical notch pathway enhances cardiac specification of APLNR+ in vitro SHF progenitors via preferential MAML1 interaction with MEF2C to enhance its transcriptional activity.
In summary, this study has identified in vitro cardiac differentiation is analogous with in vivo SHF cell specification and APLNR as a surface marker for genetic label-free isolation of in vitro multipotent SHF progenitors. This platform allows for a better understanding of SHF development and a consistent source for the generation of cardiac lineages with applications in bioengineering, drug screening and cardiac regeneration.published_or_final_versionPaediatrics and Adolescent MedicineDoctoralDoctor of Philosoph
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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