1,721,042 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
All trans retinoic acid recruits Smad3 to drive TGF beta signaling in lung fibroblasts : new insights for the management of bronchopulmonary dysplasia with retinoids
Full text linkThere is currently much interest in using retinoids such as all trans retinoic acid (ATRA), or retinoid analogs such as vitamin A (retinol), in the management of premature neonates at risk for the development of bronchopulmonary dysplasia (BPD). Current clinical evidence is contradictory, with some reports suggesting benefits, while other reports suggest no impact, or a deleterious effect of retinoid administration. In contrast, retinoids generally perform very well in animal models of BPD, and serve to stimulate lung development, particularly alveolarization. In this study, we attempted to evaluate the impact of retinoids on the activity of the transforming growth factor (TGF) beta signaling pathway, a pathway that has been credited with high importance in driving lung development and alveolarization.We employed NIH/3T3 mouse fibroblasts to study the impact of ATRA on TGF beta signaling. While the NIH/3T3 cell line differs in some important aspects to that of lung fibroblasts, it is reasonable to assume that NIH/3T3 have a similar biological behavior to that of airway fibroblasts in tissue. We observed that ATRA had a dramatic effect on TGF beta signaling in NIH/3T3 cells. Pre-treatment of NIH/3T3 cells with ATRA caused a strong increase in TGF beta signaling, as assessed by phosphorylation of Smad3, and by a luciferase-based promoter-reporter assay. Further studies revealed that this effect was caused by the ability of ATRA to strongly increase Smad3 expression levels in NIH/3T3 cells. Using plasmid-mediated overexpression of the smad3 gene, we confirmed these observations, and showed that increased Smad3 levels in NIH/3T3 cells can indeed make the NIH/3T3 cells more responsive to TGF beta. To further support these data, we also down-regulated smad3 gene expression using siRNA directed against Smad3, and demonstrated that by down-regulating smad3 expression, the pro-TGF beta signaling effect of ATRA was lost. We also demonstrated that the degree of change in smad3 gene expression caused by ATRA stimulation is sufficient to cause a significant change in the TGF beta signaling pathway.Together, these data demonstrate that ATRA administration can upregulate TGF beta signaling in NIH/3T3 cells. This may have important consequences for lung development, since TGF beta drives multiple fibroblast functions such as extracellular matrix (ECM) production, as well as ECM reshaping in developing organs. Future studies should address the cross-talk of TGF beta and retinoid signaling on other lung cell types, primary cells, and in animal models of BPD, in order to complete the picture of how retinoids may influence lung organogenesis. With a better understanding about the impact of retinoids on lung fibroblasts function and lung development one might be able to optimize the administration of retinoids in patients with BPD and thus improve clinical outcome.Aktuell besteht ein großes Forschungsinteresse in der Verwendung von Retinoiden wie Vitamin A Säure (englisch: all trans retinoic acid (ATRA)) oder Retinoid-Analoga wie Vitamin A (Retinol) bei der Behandlung von Frühgeborenen, welche an Bronchopulmonaler Dysplasie (BPD) erkrankt sind. Der klinische Effekt von Vitamin A bei der Behandlung von BPD ist sehr widersprüchlich. Manche Studien berichten Erfolge, wobei andere Studien keinen Effekt oder sogar schädliche Auswirkungen bei der Verwendung von Vitamin A berichten. Hierzu steht im Widerspruch, dass Retinoide meist eine sehr gute Wirksamkeit in BPD Tiermodellen zeigen, wo sie die Lungenentwicklung, insbesondere die Alveolarisierung fördern. In dieser Studie untersuchten wir die Auswirkung von Retinoiden auf die transformierende Wachstumsfaktor beta (englisch: transforming growth factor (TGF) beta) Signalkaskade. Der TGF beta Signalkaskade wird eine wichtige Bedeutung für die Lungenentwicklung und Alveolarisierung zugeschrieben.Zur Untersuchung des Einflusses von ATRA auf die TGF beta Signalkaskade verwendeten wir NIH/3T3 Maus-Fibroblasten. Diese unterscheiden sich in einigen wichtigen Aspekten von Lungenfibroblasten, jedoch wird angenommen, dass NIH/3T3 Zellen ähnliche biologische Funktionen wie Lungenfibroblasten erfüllen. Wir konnten zeigen, dass ATRA einen dramatischen Effekt auf die TGF beta Signalkaskade in NIH/3T3 Zellen hat. Die Vorbehandlung von NIH/3T3 Zellen mit ATRA resultierte in einer starken Zunahme der TGF beta Signaltransduktion, was durch die Bestimmung der Phosphorilisierung von Smad3 und in einem Luciferase Promoter-Assay untersucht wurde. Weiterhin konnte gezeigt werden, dass dieser Effekt durch ATRA hervorgerufen wurde, welches die Fähigkeit besitzt, die Smad3 Expression in NIH/3T3 Zellen zu erhöhen. Wir konnten mit Hilfe einer Plasmid-vermittelten Überexpression des smad3 Gens diese Beobachtung bestätigen und konnten zeigen, dass durch eine Erhöhung von Smad3 in NIH/3T3 Zellen diese Zellen gegenüber TGF beta sensibilisiert werden. Um diese Beobachtung zu bestätigen, unterdrückten wir die Smad3 Gen Expression unter der Verwendung von siRNA gegen smad3 und zeigten durch die Reduktion der smad3 Expression einen Verlust der ATRA-abhängigen TGF beta Stimulation. Des Weiteren konnte beobachtet werden, dass das Ausmaß der smad3 Gen Expression durch ATRA intensiv genug ist, um signifikante Veränderungen in der TGF beta Signalkaskade zur Folge zu haben.Zusammenfassend konnte festgestellt werden, dass die Administration von ATRA die Aktivität der TGF beta Signalkaskade in NIH/3T3 Zellen erhöhen kann. Diese Beobachtung könnte wichtige Auswirkungen auf die Lungenentwicklung haben, da TGF beta verschiedene Funktionen von Fibroblasten reguliert. Hierzu zählt die Produktion von extrazellurärer Matrix (ECM), aber auch der Umbau der ECM bei sich entwickelnden Organen. Ergebnisse dieser Studie bilden eine Basis für zukünftige Studien, welche die Interaktion von TGF beta und Retinoiden in anderen Zelltypen wie z.B. primären Zellen, aber auch in BPD Tiermodellen untersuchen sollten, um den Einfluss von Retinoiden bei der Organentwicklung weiter zu verstehen. Mit einem besseren Verständnis über die Bedeutung von Retinoiden auf die Funktion von Fibroblasten und auf die Lungenentwicklung besteht das Potential, den therapeutischen Einsatz von Retinoiden bei BPD zu optimieren und den Verlauf der Erkrankung positiv zu beinflussen
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
Immunological and genetic determinants of pulmonary outcome in school aged children
Full text linkBackground: The prevalence of respiratory disorders in children has steadily increased over the past decades to such an extent that asthma is now the most common chronic disease of childhood. Childhood asthma resembles a complex syndrome rather than a single disease, and includes many wheeze phenotypes, making its diagnosis challenging. Most likely, it is not a single risk factor that determines whether a child develops asthma, but several risk factors (e.g. environmental, immunological, genetic, onset of respiratory symptoms) that each make small contributions to the development of the disease. Already infancy, lung function tests are available to assess airway disease. These tests are predominantly used in patients with Cystic Fibrosis (CF), for whom preservation of normal lung function is crucial. Despite recent advances in lung function testing, several methodological issues remain unanswered. Higher quality tests are required in order to effectively study the various risk factors involved in the development of complex airway diseases
Aim: The first aim was to describe methodological issues during infant lung function testing in order to improve their quality. The second aim was to study different risk factors for asthma development, and to investigate their association with respiratory diseases during childhood.
Methods: The study was conducted within the prospective Basel-Bern infant lung development (BILD) cohort, a population-based cohort of unselected infants of Central-European origin. The survey collects prenatal data via standardized interviews and cord blood samples for the assessment of immunological and genetic information. During the first year of life, research nurses call the parents weekly to assess the occurrence of respiratory symptoms. Pulmonary function tests, as well as measurement of fractional exhaled nitric oxide (FeNO) to assess airway inflammation, are completed at 5 weeks of age, and again at 6 years of age during follow-up.
Results: We provided specific recommendations on how to improve outcomes from infant lung measurements. Furthermore, we measured airway obstruction using the interrupter technique (Rint) in unsedated infants shortly after birth, and were able to show that measurements were feasible but had a high variability. We compared Rint between term and preterm infants, and found that Rint was higher, and variability of Rint lower, in term-born infants. We assessed FeNO in healthy newborn infants, and in infants with CF. FeNO at birth had no predictive value for asthma development at school age. In CF patients, FeNO at birth was lower compared to matched healthy controls.
We could also show that polymorphisms in the chitinase 3-like 1 (CHI3L1) gene encoding YKl-40 were associated with asthma at 6 years. There was some indication that increased YKL-40 levels at birth may also be involved in the development of airway disease. We also developed a novel method to characterize the time series of prospectively assessed respiratory symptom scores during infancy. This method assesses symptom dynamics in an observer-independent manner. Using this method, we were able to identify a high-risk phenotype, which was predominantly male, and contained more infants exposed to maternal asthma, and environmental tobacco smoke. This phenotype was also at increased risk for asthma and atopy at school age.
Conclusions: Infant lung function is useful to study airway disease at an early age, and outcomes can be improved by applying minimal changes in analyses algorithms. Assessment of airway obstruction in infants is feasible, but measurements require careful interpretation due to the high variability. We found some indication that FeNO levels early in life are determined by environmental factors and the child’s genetic profile. In CF patients, FeNO after birth was associated with the severity of the genetic mutation. In healthy infants, FeNO levels early in life seem to be influenced by environmental exposures.
Our findings contribute additional, relevant knowledge on asthma risk factors and their association with respiratory symptoms from birth through school age. We found associations between genetics and the immunological status at birth with asthma at school age. The development of asthma may also depend on respiratory symptoms early in life. We could show that the pattern of symptom deterioration and recovery during the first year of life determines whether or not a child has persistent wheezing until school age
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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