1,721,029 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Venous arterialization for chronic limb-threatening ischemia: Past, present, and future
No full textChronic limb-threatening ischemia (CLTI) is a significant facet of atherosclerotic disease that has major medical and functional consequences. With the number of diabetic patients on the rise and improved life expectancy, has also come a greater awareness and wider adoption of endovascular techniques; thus, amputation rates continue to fall.1-3 We expect that patients will be older, have more advanced comorbidities, and will have had more prior interventions. This may translate to a greater proportion of them presenting with no-option CLTI. Venous arterialization may be a viable alternative to preserving these limbs. This thesis starts with a general introduction that provides an update on the history and development of the venous arterialization. After this the thesis consists of three parts:
Part 1 is entitled; the open venous arterialization
Part 2 is entitled; percutaneous deep venous arterialization (pDVA, LimFlow procedure)
Part 3 is entitled; postoperative care and follow-up of the venous arterialization
The first part provides information about the open superficial venous arterialization. In Chapter 2, a superficial venous arterialization cohort and pedal bypass cohort of two Dutch hospitals is analysed, with promising results in a group of patients for whom no other reconstructive treatment options were available. Although the pedal bypass is still the gold standard (if a target artery is present), distal venous arterialization is a good alternative due to comparable results and its simplicity. The current evidence was analysed in a systematic review and meta-analysis in Chapter 3 and suggests that venous arterialization is a valuable treatment option in selected patients with no-option CLTI. These otherwise unsalvageable legs can be treated with acceptable morbidity and mortality. However, optimization and standardization of techniques are needed. The venous arterialization should always be considered in patients without distal arterial outflow vessels.
The second part is about the percutaneous deep venous arterialization (pDVA). In Chapter 4, the first experience with the pDVA in humans is published, applied to a cohort of patients with no-option CLTI. The dual catheters, guided by ultrasound imaging, provide a reliable way to percutaneously create the AVF between a tibial artery and a deep tibial vein. Assisted by a percutaneously introduced valvulotome, arterial blood can now be directed to the veins of the foot. In this small cohort of patients, pDVA appears to be a safe and feasible procedure that effectively improves limb oxygenation, encourages wound healing, and potentially, avoids major amputation.
The experience, after this first publication, from four centers between 2014 and 2018, is analysed in Chapter 5. This study presents midterm results from the largest population of patients with no-option CLTI treated with pDVA using the LimFlow device. In this complex group of patients, the LimFlow device demonstrated high technical success and amputation-free survival rates of 67% coupled with good wound healing at up to 24 months. In selected patients with no-option CLTI, pDVA is a safe and effective treatment to prevent amputation and heal wounds. A new international multicenter prospective study, PROMISE International, has been started to validate these outcomes in a larger cohort, and the protocol is described in Chapter 6.
The last part of this thesis is about the postinterventional care of the venous arterialization. Chapter 7 is the first analysis of duplex ultrasound (DUS) measurements in post-pDVA patients. The venous arterialization needs time to mature before becoming effective. Stenoses or occlusions can frequently occur during this period, and therefore, there is a high need for more insight in DUS interpretation to detect failure of the arteriovenous circuit and preserve the limb. This study showed that surveillance of the arteriovenous circuit can be performed by DUS and we determined cut-off values to define the presence of stenosis or occlusions, but the small sample size of the study does not allow firm conclusions to be drawn.
A guideline for post-pDVA care is given in Chapter 8. Based on literature and clinical experience of 24 patients from Alkmaar and Singapore, we summarize the different techniques proposed and provide an algorithm for the challenges that interventionalists can face in the follow-up period after a pDVA. The most important, is the acknowledgement that the pDVA needs 6 weeks to develop before becoming effective. Other key elements are edema treatment, pain control, wound care and a staged amputation strategy.
The postprocedural management can be as challenging as the procedure itself but has not been a priority for further investigation
Variations on the Author
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Carotid Stenosis and Atrial Fibrillation as Targets for Individualised Prevention of Ischaemic Stroke
No full textThe studies in this dissertation aim to reduce stroke incidence by improving prevention strategies for atrial fibrillation (AF) and carotid stenosis-related ischaemic strokes. AF and carotid stenosis are usually clinically silent until occurrence of the ischaemic stroke. Prevention strategies should be considered in patients in whom AF or carotid stenosis has caused an ischaemic stroke or a transient ischaemic attack but should not be delayed until after these events.
Screening programmes to detect AF and carotid stenosis can improve detection rates, but systematic population-level screening has a low yield because these conditions are relatively uncommon. Targeted screening makes screening more effective. Most simply, this involves screening above a certain age threshold. Risk prediction models combine multiple characteristics, such as age, sex, and medical history, to provide risk predictions for patients individually. These models can be used to target screening to high-risk patients. We determined which risk prediction models could detect AF and carotid stenosis reliably.
Prevention strategies to reduce risks of ischaemic stroke are well defined for patients in whom AF is detected but are more controversial for carotid stenosis. Especially the role of carotid endarterectomy (surgery to remove the carotid stenosis) became less clear over time because of improved medical preventive therapy. We showed that carotid endarterectomy should be performed by high volume surgeons in high volume hospitals, and that procedural complications of carotid endarterectomy, that partly determine the net clinical benefit, can be predicted reliably for each patient individually
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
Risk Stratification for Adverse Events after Carotid Endarterectomy
No full textPatients with symptomatic carotid artery stenosis have a high risk of future ipsilateral cerebrovascular events and this risk can be effectively reduced by a surgival removel of the carotid plaque (carotid endarterectomy, CEA). Despite CEA, these patients maintain at high risk for future major cardiovascular events (MACE) after CEA due to the systemic nature of atherosclerosis. Novel options for intensification of medical treatment (intensive lipid lowering or anticoagulants or new anti-inflammatory drugs) are emerging but have hazardous side effects and are expensive. Therefore, risk stratification tools for MACE are warranted. Clinical parameters fail to accurately discriminate between patients at high risk of MACE and those at low risk. Biomarkers could improve risk prediction models. This thesis investigates several types of biomarkers; circulating blood markers, radiographic markers on cerebral imaging and genetics, in relation to future cardiovascular events in patients undergoing CEA. These biomarkers were also associated to histological characteristics of the carotid plaque in order to increase our understanding of the complex mechanisms of atherosclerosis. In the future, these biomarkers can be useful to select high-risk patients that qualify for intensified medical treatment or follow-up. Ultimately, these biomarkers incorporated in risk prediction models could help physicians select appropriate patients for specific treatments
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