1,720,959 research outputs found
High-frame-rate coherence imaging of the heart with ultrasound diverging waves
No full textSeveral techniques have been proposed up to now to achieve higher temporal resolution in echocardiography. Among these, the use of diverging beams, which insonify a large region of interest, allows to significantly increase the frame-rate, but at the cost of a reduced signal-to-noise ratio. For this reason, in this paper we propose to combine high-frame-rate imaging, by transmitting diverging waves (DWs), to the Short-Lag Spatial Coherence (SLSC) technique in reception, which provides images of the coherence of backscattered echoes and is known to yield improved contrast in scenarios with high-clutter. We test this combined method first on phantom acquisitions and then on in vivo cardiac scans, i.e. on apical views of the heart. Results show that SLSC can provide improved contrast ratio (CR) and generalized contrast-to-noise ratio (GCNR) with respect to the classic Delay and Sum (DAS) as the number of transmitted DWs increases, particularly when clutter is present. Indeed, cardiac images show improved apex visibility and artifact suppression in the heart chambers with SLSC, achieving high contrast and high frame-rate at the same time
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
RAGE gene polymorphism in heart failure patients with and without angiographic evidence of significant coronary atherosclerosis.
No full textHeart failure (HF) is a multifactorial disorder in which clinical, environmental and genetic components take part. For this reason it is possible that common gene variants could affect development, progression and response to pharmacological therapy. In recent years the role of AGEs in the pathogenesis of cardiovascular diseases has become recognized but little is known about the role of the AGE RAGE system in heart failure. The aim of the present study was to identify possible relationship between -374 T/A RAGE gene polymorphism with heart failure. The population in this study consists of 386 subjects with HF, selected according to the presence of depressed Left Ventricular Ejection Fraction (LVEF) less than45 percent, and 639 patients with CAD documented at coronary angiography. Within the population with HF there are 228 patients with disease secondary to not ischemic cause and 158 with post-ischemic condition. The sample of AA genotype was significantly lower in patients with post-ischemic HF in respect to HF secondary to non-ischemic causes (pless than0.001). A significant difference between the two groups was also observed regarding the allele frequency. In addition, differences in the allelic and the genotypic frequencies of homozygous genotypes were found between the HF patients free from evidence of coronary significant lesions and patients with at least one hemodynamically significant coronary lesion, both HF and CAD. In patients with at least one vessel compromised the presence of A allele and the homozygous AA genotype were significantly lower than in patients with lesion-free coronary. In conclusion, our research reveals that the -374 T/A polymorphism is related to the genesis of atherosclerotic coronary artery disease but not to its evolution. The protective role of AA genotype in respect to atheromatous disease is therefore confirmed also in the HF population with non-ischemic origin
Possible role of -374T/A polymorphism of RAGE gene in longevity.
No full textDemographic and social changes in the last decades have resulted in improvements in health and longevity. The survival of elderly people has improved significantly and thus centenarians are becoming the fastest growing population group. Environmental, genetic, and accidental factors have influenced the human life span. Researchers have gained substantial evidence that advanced glycation end products may play an important role in the processes of physiological aging. The aim of the present study was to investigate any differences in the frequencies of -374T/A polymorphism in subjects aged >90 years and in middle-aged individuals. We observed association between the A allele and genotype homozygous for this allele (AA) with a longer life expectancy in the male population. In particular, there was a prevalence of AA genotype and A allele in long-living subjects and a prevalence of the allele T in middle-aged subjects, indicating a possible protective role of the allele A to aging. In conclusion, our results support the hypothesis that longevity is the result of a good functioning of the immune system and a presumable hyper-expression of variants of anti-inflammatory genes of immunity. The differences in the genetic regulation of inflammatory processes may influence the presence of age-related disorders
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