1,721,028 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
Epidemiology and Risk Factors of Equine Parvovirus-Hepatitis, Hepacivirus, Pegivirus caballi, and Pegivirus equi in U.S. Horses
Full text linkEmerging equine viruses such as Equine parvovirus-hepatitis (EqPV-H), Equine hepacivirus (EqHV), Pegivirus caballi (P. caballi), and Pegivirus equi (P. equi) have recently gained recognition as significant contributors to equine infectious disease ecology and hepatic pathology. EqPV-H, in particular, has been implicated in Theiler’s disease (TD), a potentially fatal form of acute hepatitis in adult horses. Despite growing global interest, limited data are available describing their molecular epidemiology in the United States. This study was designed to address that gap through a comprehensive molecular survey aimed at evaluating prevalence and potential host-associated risk factors for these viruses across multiple states.
A total of 1,195 equine serum samples were collected from diagnostic submissions and surveillance programs across Alabama, Georgia, and Texas. Using optimized quantitative PCR and RT-qPCR assays targeting conserved regions of each viral genome, the study quantified viral prevalence and examined associations with host demographics, including age, sex, breed, and geographic origin. Statistical analyses, performed in RStudio, employed both univariable and multivariable logistic regression models to identify significant predictors of viral positivity, supported by pairwise Fisher’s exact and Wilcoxon rank-sum tests for prevalence and viral burden comparisons, respectively.
EqPV-H showed the highest prevalence (19.3%), followed by EqHV (5.6%) and P. caballi (1.7%), with only two cases of P. equi detected. EqPV-H infection was significantly associated with breed, age, and sex, whereas EqHV was primarily associated with breed, particularly Thoroughbreds and Quarter Horses. Demographic analysis revealed that EqPV-H-positive horses were significantly older, and male horses had 1.62 times the odds of infection compared to females. Breed-specific associations were also identified: Tennessee Walking Horses had higher odds of EqPV-H positivity (OR = 2.46), while Quarter Horses (OR = 4.16) and Thoroughbreds (OR = 9.64) showed increased odds of testing positive for EqHV. EqPV-H-positive horses also exhibited significantly higher viral loads compared to animals positive for EqHV or pegiviruses. No host-related risk factors were identified for pegiviruses, though P. caballi-positive cases were only identified from horses in Georgia. Viruse sequences identified in this study were similar to the reported ones in the United States and other regions. This largest molecular survey highlights the widespread distribution of EqPV-H and EqHV in U.S. horses and underscore the importance of continued surveillance, particularly in high-risk breeds and settings. The data provides a foundation for developing preventive strategies and improving understanding of the epidemiology and potential clinical impact of these emerging equine viruses. These results expand the epidemiological landscape of equine hepatotropic viruses in in horses in the United States, offering valuable insights into their ecological niches and transmission patterns. EqPV-H’s dominance in both prevalence and viral load reinforces its central role as a hepatotropic pathogen of concern. While EqHV remains largely subclinical, its occurrence in specific high-performance breeds raises questions regarding chronic infection.
In conclusion, this molecular survey represents one of the most extensive state-level assessments of EqPV-H, EqHV, P. caballi, and P. equi in the United States to date. The findings substantiate the endemic nature of EqPV-H and EqHV and delineate host and regional factors influencing their distribution. Collectively, these results underscore the urgency of integrated monitoring systems and molecular diagnostics to track the spread of these emerging equine viruses and mitigate their impact on equine health and industry sustainability.
Resistance to colistin and carbapenem among Enterobacteriaceae recovered from human and animal sources is associated with multiple genetic mechanisms
Full text linkColistin and carbapenem and are important last-resort antimicrobials to treat infections caused by multidrug-resistant Gram-negative bacteria. Understanding the genetic mechanisms conferring resistance to colistin and carbapenem and their prevalence are critical in the development of preventive measures. There is little information on resistance to colistin and carbapenem among Enterobacteriaceae in Nigeria and sub-Saharan Africa. Developing nations have poor sanitation practices and policies regulating use of antibiotics, enhancing the spread of antimicrobial resistance. The emergence of resistant bacteria to these last-resort drugs has necessitated a study to understand the genetic mechanisms conferring resistance and their prevalence, which is critical in the development of preventive and therapeutic measures. While there has been quite a number of investigations and good antimicrobial surveillance practices in the United States, very few reports are available about the colistin and carbapenem resistant bacteria in animals.
The research in this thesis aims to investigate the prevalence of colistin and carbapenem resistance from human and animals in Nigeria, and from pigs in the USA, and understand the genetic mechanisms driving the resistance. A total of 1,119 human (stool from outpatients and urine from ICU patients) and animal (rectal swabs from cattle, dogs, pigs, poultry) samples were collected from Benue State, Northcentral, Nigeria. 583 non-duplicate Enterobacteriaceae were recovered from these samples using phenotypic methods and whole-genome sequencing (WGS). Of the 583 isolates, 17.0% (99/583) were resistant to colistin, 18.9% (110/583) were resistant to carbapenem, and 9.1% (53/583) had concurrent carbapenem-colistin resistance. PCR (mcr-1 to mcr-9) and whole-genome sequencing (WGS) identified mcr in 21.2% (21/99) of colistin-resistant isolates: mcr-1.1 (n = 13), mcr-8.1 (n = 5), mcr-1.1 and mcr-8.1 (n = 2), and mcr-1.1 and mcr-5 (n = 1). Of the 21 mcr-positive strains, 9 were isolated from human samples, with 8 being Klebsiella pneumoniae, and 6 of these human K. pneumoniae had a high colistin MIC (>64 μg/mL). In contrast, 9 of the 12 mcr-positive animal isolates were Escherichia coli, of which only 2 had a colistin MIC of >64 μg/mL.
The carbapenem minimum inhibitory concentrations was between 2 and 32 µl/ml. Interestingly, none of the carbapenem resistant bacteria produced any carbapenemase genes. However, they had a combination of efflux pump mutations, outer membrane protein mutations, and production of extended spectrum beta-lactamases. The population structures of the bacterial isolates carrying concurrent colistin and carbapenem resistance were highly polyclonal, distributed into 37 different sequence types and characterized by the presence of internationally recognized high-risk clones in Klebsiella pneumoniae ST11, ST58, ST340-human isolates) and in E. coli (ST58, ST744, ST410 -animal isolates). Novel and existing mutations were also observed amongst the resistant isolates. Escherichia coli was the most commonly isolated organism from animal samples, while Klebsiella pneumoniae was most commonly isolated from human samples.
On the contrary, of the 85 commercial swine fecal samples collected Auburn, Alabama, USA, carbapenem-resistant isolate was not identified. However, molecular analysis by FRET-PCR identified mcr genes from 34.5% (38/110) isolates, with mcr-2 gene as the most prominent 73.7% (28/38). Of the mcr positive isolates analyzed for speciation by 16S rRNA, E. coli (70.8%) was the most commonly isolated, followed by K. pneumoniae (25.0%), and Salmonella enterica (4.2%). In two of the mcr- positive isolates, WGS identified (marA, ampC, pmrC, pmrE, pmrF, and blaEC) known to confer multiple antibiotic resistance, and blaAMPH was identified in only one of the isolates.
This study is the first to report mcr-1 in Alcaligenes faecalis and the emergence of mcr-5 and mcr-8 in Nigeria. WGS determined that mcr-1 was localized on an IncX4 plasmid and that 95.2% of mcr-1 harboring isolates (20/21) transferred colistin resistance successfully by conjugation. This study adds valuable information regarding resistance to colistin and carbapenem with implications for both human and animal health. These findings highlight the global spread of colistin resistance and emphasize the urgent need for coordinated global action to combat resistant bacteria. The presence of high-risk clones in these isolates provides worrisome evidence that humans and animals may serve as reservoirs and vectors for global microbial spread and should therefore be continuously monitored.
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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