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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
Polycystic ovary syndrome : preconception, pregnancy and offspring health
No full textPolycystic ovary syndrome (PCOS) is the most common endocrine disorder in women of reproductive age, with a reported population incidence between 6-15%. PCOS is a heterogeneous reproductive disorder, which is diagnosed when at least two out of the three following criteria are present: oligo- or anovulation, clinical or biochemical signs of hyperandrogenism and polycystic ovaries. Early manifestations of the syndrome are often irregular or absent menstrual bleeding, anovulatory infertility and/or clinical manifestations of androgen excess, such as acne or hirsutism. Subsequently, there are metabolic disturbances associated with PCOS, of which some are already present early in life (obesity, insulin resistance) and others appear later in life (dyslipidaemia, type 2 diabetes). When a pregnancy is achieved, women with PCOS have an increased risk of maternal and neonatal complications. The aims of this thesis were to gain more insight into the incidence and risk factors of pregnancy complications in women with PCOS, its pathophysiology and the impact of the syndrome on the cardiovascular and metabolic health of their offspring.
We demonstrated that women with PCOS with a singleton pregnancy have an increased incidence of developing gestational diabetes (GDM; OR 4.15), of delivering a small for gestational age infant (OR 3.76) and of induced preterm delivery (7.77). Women with the hyperandrogenic PCOS phenotype (with high levels of free testosterone) are demonstrated to have a higher incidence of pregnancy complications compared with the normo-androgenic phenotype. We developed a prediction model with preconception characteristics for one of the most common pregnancy complications in women with PCOS, gestational diabetes. The combination of fasting glucose, fasting insulin, SHBG, androstenedione and first-degree relatives with type 2 diabetes seemed to predict the development of gestational diabetes already before conception with an accuracy of 0.87. With this model, women with PCOS who are at increased risk of developing GDM could be identified and followed more intensively during pregnancy in order to prevent them from developing GDM or reduce the consequences when GDM is diagnosed. Subsequently, placentas from women with PCOS were compared with placentas from women with uncomplicated pregnancies who delivered at term. We found that placentas from women with PCOS show more signs of inflammation, thrombosis, and villous immaturity compared with placentas from women without PCOS, independent of pregnancy complications (GDM, PIH and PE). These results may reflect signs of vascular damage or foetal hypoxia. Finally, we compared the cardiovascular health of children from women with PCOS with children from a population-based reference group. We demonstrated that children from women with PCOS have obvious subclinical alterations in metabolic and cardiovascular health, which is reflected by an increased pulse pressure and a higher left ventricle diameter in the young age category as well as a higher carotid intima media thickness, subcutaneous fat mass, total cholesterol level, triglyceride and LDL-cholesterol level in the older age category. All these findings represent risk factors that are associated with an increased cardiovascular disease risk later in life
Biopsy techniques to study the human placental bed
No full textBackgroundThe physiologic transformation of uterine spiral arteries in the human placental bed is essential for a healthy pregnancy. Failure of this transformation due to deficient trophoblast invasion is widely believed to underlie pregnancy complications such as preeclampsia, foetal growth restriction, miscarriage and preterm labour. Understanding of invasive behaviour and remodelling properties of trophoblasts in the uterine wall is essential in elucidating the aetiology of these pregnancy complications. However, there is a lack of satisfactory specimens of the placental bed to enhance our knowledge on the mechanisms that control trophoblast invasion. Several techniques can be used to obtain biopsies from the placental bed and sample handling can be executed differently depending on the research question.MethodsThis systematic review provides an overview of all studies investigating the placental bed and sampling techniques used. Papers that described surgical techniques, specimen handling, complications and/or success rate of the placental bed biopsy procedures were included. Placental bed biopsies are an essential and feasible technique to study abnormalities in the placental bed associated with pregnancy complications.ResultsDepending on the technique used the likelihood of sampling a spiral artery and trophoblast from the placental bed is 51%–78% per case, without significant complications.ConclusionsCaution is needed when interpreting data if the placental bed is subjected to labour. We propose a uniform sampling technique and conservation protocol for the study of the placental bed and provide tools for selection of the appropriate technique for future placental bed collections
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
Innovations in Down syndrome screening
No full textDown syndrome (DS) is the most common chromosomal abnormality, with an incidence of approximately 1 per 500 to 800 live births. The first-trimester combined test is mostly used for the prenatal prediction of carrying a child with DS. The test is composed of the maternal serum parameters pregnancy-associated plasma protein A (PAPP-A) and the free beta subunit of human chorionic gonadotropin (f?-hCG), and an ultrasound measurement of the foetal nuchal translucency (NT), combined with maternal age. The detection rate (DR) of DS screening in the Netherlands is currently 70-75%, which is rather low as compared to other countries. The aim of this research was to investigate ways to improve the performance of the current DS screening programme. The extra chromosome in DS not only leads to anomalies of the foetus, but also of the placenta. The inability of placental cells to develop properly is associated with a decrease of trophoblastic products. If this differential expression is traceable in maternal blood these products could have potential as new screening markers. Several markers have been investigated and found to be potentially useful as predictors of DS. One of those markers is placental protein 13 (PP13) which was found to be decreased in DS pregnancies. Moreover, serum concentrations of a disintegrin and metalloprotease 12 (ADAM12) and placental growth factor (PlGF) are decreased, while total hCG (thCG) is increased in first-trimester DS pregnancies. However, the addition of these markers to the current first-trimester combined test only slightly increases the DR. Therefore, a dedicated search for more markers was set up. An extensive review of the literature was carried out to study normal placental development and function during early pregnancy. Furthermore, a bioinformatics approach was developed using data from the literature on genes and protein expression. This way, a list of potential DS screening markers was generated. The list included three biomarkers that are already used for DS screening and several others, among which PP13 and PlGF. A more experimental approach was carried out by analyzing 90 different proteins from a pre-existing immunoassay. By comparing the protein concentrations in a small cohort of DS and control sera, seven potential screening markers were identified. To confirm the predictive value of these seven markers a subsequent validation study was carried out. Epidermal growth factor (EGF) and EN-RAGE were confirmed to be potential screening markers for DS and improved the DR of the current first-trimester combined test with approximately 6%. In addition, Cancer Antigen 19-9 (CA19-9), was found to be strongly predictive for DS and even further increased the DR. It turned out that the predictive power of serum markers differs within the first trimester. Therefore, it would be useful to draw two separate blood samples and analyze several markers to increase the DR of first-trimester screening to almost 90%. If such a screening test is to be developed, simultaneous assessment of markers is crucial and demands innovation of the test, i.e. by using Antibody microarrays
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
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