1,721,256 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
Periodontitis and neurodegenerative diseases
No full textMany neurodegenerative diseases cause progressive deterioration in specific areas of the nervous system. This affects both the structure and function of neural tissues. Two of the most common neurodegenerative diseases are Alzheimer disease (AD) and Parkinson disease (PD). AD initially affects cognitive function, wherease PD commonly begins by affecting motor function, although later in the PD trajectory cognitive impairment often ensues. Both conditions are chronic, debilitating and progressively limit the individual’s ability to function independently. As the likelihood of developing neurodegenerative diseases increases with age, the global burden of both AD and PD is set to rise steeply. Between 1980 and 2015, average age at death increased from 73.1 to 81.6 years in the UK and 73.7 to 78.7 years in the USA, a trend seen in most countries with an inverted population age pyramid1. The 2016 worldwide estimates of those living with AD or PD are 44 million and 6 million, respectively2. In the UK alone, the number of people with PD is approximately 16,000. For AD, this is 500,000, representing 62% of those with dementia. In 95% of cases the age of diagnosis is over 65 years; prevalence of dementia rises from 7% over the age of 65, to 13% over the age of 75, and approximately 60% of those affected overall are female3. The annual cost of dementia in the UK is approximately ￡26.3 billion3, and the annual financial impact of living with PD in the UK has been estimated to be over ￡16,500 for each individual household affected, costing the UK economy between ￡450 million and ￡3 billion per year4. There is also a high social cost, as these diseases often affect the quality of life of carers and loved ones as well as the individuals affected. Periodontitis has for some time been associated with neurodegenerative diseases, largely because of the obvious related decline in ability to provide self-care for the teeth and surrounding tissues. However, it is now being recognised that the relationship might be bi-directional5. There is a growing body of evidence suggesting a potentially proactive role for periodontal pathogens and the periodontal chronic low grade inflammatory response in the development of some types of neurodegenerative diseases. Like many chronic inflammatory diseases, periodontitis is similarly age-related, with onset commonly occurring in mid-life.Currently there is no cure for AD or PD; treatment of neurodegenerative conditions is limited to, at best, delaying the worsening symptoms. This is in some ways similar to the goal of conventional periodontal treatment, which is to slow the progression of periodontal destruction, ideally reaching a state of periodontal stability. The key to developing improved treatment modalities is likely to be found in discoveries relating to the pathogenesis of these conditions. Whilst the causes of the neuropathology of AD and PD remain somewhat elusive, they are likely to be multifactorial. It has been known for some time that peripheral infection is a strong risk factor for the development and progression of AD in elderly populations. Peripheral infection is a common cause of delirium in the elderly, and delirium has been shown to increase the risk of developing dementia eight-fold over the following 10 years6. Cognitive decline has also been shown to occur at a more rapid rate following a period of delirium in those already diagnosed with AD7. With increased age, and in AD and PD, the blood–brain barrier (BBB) can have increased permeability8,9. However, it is likely that the initiating factors associated with AD or PD occur in mid-life and may be low level, chronic infections. It has recently been suggested that periodontal pathogens and/or the peripheral inflammatory state seen in periodontitis could be implicated in neurodegeneration10,11. These pathogens may slowly increase the permeability of the BBB and produce pro-inflammatory proteins resulting in peripheral and neural inflammation, ultimately leading to neurodegeneration. Thus both AD and PD may be driven by neuroinflammation; this chapter seeks to examine its origin and to discuss its association with periodontitis and its possible role in these two neurodegenerative diseases.<br/
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
Potential mechanisms underpinning the nutritional modulation of periodontal inflammation
No full textBACKGROUND: Periodontitis results from an inappropriate host response to pathogenic biofilms. Because traditional management approaches have failed to reduce disease prevalence, the research focus has shifted toward managing host-mediated inflammation. In this article, the author reviews the role of nutrition in the development and resolution of inflammation. METHODS: The author reviewed the biomedical literature to elucidate mechanisms by which dietary factors affect inflammatory processes and to establish what evidence exists for macronutritional and micronutritional modulation of inflammation at a cellular and molecular level. CONCLUSIONS: Hyperinflammation characterizes the periodontitis phenotype, and oxidative stress is a key orchestration point for the diverse signaling pathways, which control inflammation. Oxidative stress is modulated by diet, as well as by infection. Recent research has demonstrated that subtle shifts in nutritional status are associated independently with the prevalence of periodontitis. Moreover, the results of contemporary animal and human studies have demonstrated the role of specific micronutrients in the modulation of the host's inflammatory response by reducing inflammatory biomarkers and bone loss. CLINICAL IMPLICATIONS: The scientific community is starting to realize the health benefits of diets containing foods naturally rich in antioxidants and omega-3 polyunsaturated fatty acids, as well as the dangers of diets that are high in refined carbohydrates. Nutritional intervention studies in patients with inflammatory periodontitis are needed to evaluate the effect of nutritional approaches to periodontal management
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
Mechanisms contributing to the enhanced respiratory burst of neutrophils observed in periodontitis
Full text linkThe aim of this thesis is to investigate possible mechanisms that may contribute to neutrophil hyperactivity and hyper-reactivity. One possibility is the presence of a neutrophil priming factors within the peripheral circulation of periodontitis patients. To examine this possibility differentiated HL-60 cells and primary neutrophils were studied in the presence and absence of plasma from periodontitis patients. In independent experiments, plasma was depleted of IL-8, GM-CSF, interferon-a, immunoglobulins and albumin. This work demonstrated that plasma factors such as IL-8, GM-CSF, and interferon-a present during periodontitis may contribute towards the reported hyperactive neutrophil phenotype. Furthermore, this work demonstrated that products from Pg may regulate neutrophil accumulation at infected periodontal sites by promoting gingipain-dependent modification of IL-8-77 into a more biologically active chemokine. To elucidate whether the oxidatively stressed environment that neutrophils are exposed to in periodontitis could influence hyperactivity and hyper-reactivity, neutrophils were depleted of glutathione. This work showed that during oxidative stress, where cellular redox-levels have been altered, neutrophils exhibit an increased respiratory burst. In conclusion, this work highlights the multiple mechanisms that may contribute to neutrophil hyperactivity and hyperreactivity including gingipain-modulated activity of IL-8 variants, the effect of host factors such as IL-8, GM-CSF, interferon-a on neutrophils priming and activation, and the shift of neutrophil GSH:GSSG ratio in favour of a more oxidised environment as observed in periodontitis
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
- …
