1,721,240 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
“Humble Obedience to the Will of Heaven”: Charles Johnston’s Providential and Migratory Sensibility
No full textVariations 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
“Humble Obedience to the Will of Heaven”: Charles Johnston’s Providential and Migratory Sensibility
No full textAppropriate 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
Atherosclerosis, Mummies and Histological Analysis: A Review
No full textAtherosclerosis has always been considered as a pathology of modern life, but we know by now that it is an inevitable condition of human ageing. In fact arterial degeneration begins early in postnatal life and is progressive in all human populations even if the degree of atherosclerosis can be delayed by a lifelong avoidance of lifestyle risk factors [Wang et al., 2010]. Among the modifiable risk factors, it is clear that in general the average population of the past had poor access to fatty and well-seasoned food and practiced intense physical activity in comparison to the modern population. In every period there have been élite social classes in which there is a high consumption of fatty food associated with lack of physical exercise. Atherosclerotic disease has been identified, however, in individuals from very different social contexts and with different standard of living. For this reason we believe that a fundamental role has been played by the infectious diseases and chronic inflammatory conditions. For the past populations infections would have been very common in the daily life and it was the major cause of death. Several studies demonstrated that a prolonged inflammatory response might accelerate an atherosclerotic process in those patients who suffer from chronic inflammatory disease like rheumatoid arthritis or systemic lupus erythematosus [Kahlenberg & Kaplan, 2013]. Since atherosclerosis begins as an inflammatory reaction against endothelial cells and other components of the artery wall, it is important to take into account the role of proper oral hygiene in order to avoid periodontitis, which is a chronic inflammatory disease that affects the periodontium. Bacterial populations on the tooth surfaces are extremely numerous and it is crucial that commensal bacteria would not overwhelmed by pathogenic strains; for example, Gram-negative bacteria, has been reported to be a significant predictor of coronary heart disease [Meurman et al., 2004]. Some supposed mechanisms by which dental bacteria may contribute to the atherosclerotic disease are the activation of innate immunity and the direct involvement of mediators activated by dental plaque [Bartova et al., 2014]
For many years the anthropological studies have focused on the oral state of health, highlighting that the populations of the past suffered from different pathologies caused by incorrect eating practices or by lack of oral hygiene or by the use of the teeth as ‘third hand’. Caries, for example, is a very old disease. It has been reported in several lineages of fossil hominines like Homo habilis, H. erectus, H. heidelbergensis and H. neanderthalensis [Lanfranco & Eggers, 2012] and follows the increase of carbohydrates intake in human history from the advent of agriculture to the recently dietary changes of the Industrial Revolution. In conclusion, inflammation associated with lack of oral hygiene could have played a part in atherosclerotic disease process.
Given the post-mortemchanges seen in the vessel walls of a mummy, obtaining histologic specimens is important to confirming the diagnosis of an atherosclerotic plaque. While CT scans can be used to identify atherosclerosis in ancientmummies, this approach only detectsplaques that have already been calcified, and histological examination is necessary to detect early stages of disease.
CT scans can be used to identify atherosclerosis in ancient mummies, this approach only detects plaques that have already been calcified, and histological examination is necessary to detect early stages of disease.
The development of vascular calcification is related not only to atherosclerosis Other conditions may lead to the formation of such lesions, including aging, diabetes, disorders of calcium-phosphorus metabolism, chronic microinflammation, hyperhomocysteinemia, and chronic renal insufficiency (Davies MR, Hruska KA. Pathophysiological mechanisms of vascular calcification in end-stage renal disease. Kidney Int. 2001;60(2):472-479.) Moreover, given the poor state of preservation of the organic tissues, a differential diagnosis for the findings should include parasitic calcifications in lymphatic vessels (particularly from filariasis).
While there are other diseases such as syphilis, which can cause vascular calcification, the pattern and distribution of arterial calcification related to atherosclerosis is quite distinctive. When observing a vascular calcification on a CT (particularly 6-slice), it is not possible to distinguish lesions of atherosclerosis and mediacalcosis (Charlier, 2010
Atherosclerosis, Mummies and Histological Analysis: aA Review
No full textAtherosclerosis, a disease with a multifactorial aetiology, is characterized by the accumulation and hardening of fatty materials in the arterial blood vessels, can cause obstruction (stenosis) of the lumen. Today, it is one of the most common diseases of the developed countries, and every year thousands of people die of the complications associated with atherosclerosis.
We conducted a review of the published literature in order to identify paleopathological evidence of atherosclerosis in mummified remains that have been confirmed by histological analysis.
Results. Atherosclerosis has been histologically detected in 33 mummies, described in papers ranging in date from 1852 to the present day. Egypt is the country with the highest number of cases (22 out of 33) and at least one individual with atherosclerosis has been described on almost all continents: 4 from North America, 3 from South America, 2from Europe and 2 from Asia. The time range of the mummies is very wide, a period of about 3300 years. Of the bodies for which we have dating, the oldest is from around 1580 BC, while the most recent, which has a precise autobiography, is the Sienese Girolamo Macchi, who died in 1734 AD at the age of 86 years.
Among the modifiable risk factors (diet, smoke, physical activity), it is likely that populations in the past generally had limited access to fatty and well-seasoned food (except for élite members and noble families), and had more physical activity, when compared to populations today, due to a higher number of manual and physical work activities. However, atherosclerotic disease has been identified in individuals from very different social contexts and with different standards of living. For this reason, it is possible to speculate on the important role of infectious diseases and chronic inflammatory conditions in the development of atherosclerosis. In past populations all over the world, infections may have been very common in everyday life and were one of the major causes of death.
For the study of ancient atherosclerosis, imaging is an essential initial diagnostic tool, but, in many cases, invasive techniques such as those used in dissection, or for sampling for histological analysis, cannot be performed on mummies owing to their high historical value or museum regulations. This approach, however, only detects plaques that have already been calcified, so histological examination is required to detect the early stages of the disease. Moreover, given the postmortem changes observed in the vessel walls of a mummy, it is important to obtain histological samples in order to confirm the radiological diagnosis of an atherosclerotic plaque.
Conclusions. Although it could be supposed that atherosclerosis is a disease typical only of modern life, we know that it is an inevitable condition of human ageing. In fact, arterial degeneration begins early in postnatal life and is progressive in all human populations, even if the severity of atherosclerosis can be delayed by a lifelong avoidance of lifestyle risk factors
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
- …
