1,721,009 research outputs found
Multiomics of parkinsonism cynomolgus monkeys highlights significance of metabolites in interaction between host and microbiota
Full text linkThe gut microbiota has been demonstrated to play a significant role in the pathogenesis of Parkinson’s disease (PD). However, conflicting findings regarding specific microbial species have been reported, possibly due to confounding factors within human populations. Herein, our current study investigated the interaction between the gut microbiota and host in a non-human primate (NHP) PD model induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) using a multi-omic approach and a self-controlled design. Our transcriptomic sequencing of peripheral blood leukocytes (PBL) identified key genes involved in pro-inflammatory cytokine dysregulation, mitochondrial function regulation, neuroprotection activation, and neurogenesis associated with PD, such as IL1B, ATP1A3, and SLC5A3. The metabolomic profiles in serum and feces consistently exhibited significant alterations, particularly those closely associated with inflammation, mitochondrial dysfunctions and neurodegeneration in PD, such as TUDCA, ethylmalonic acid, and L-homophenylalanine. Furthermore, fecal metagenome analysis revealed gut dysbiosis associated with PD, characterized by a significant decrease in alpha diversity and altered commensals, particularly species such as Streptococcus, Butyrivibrio, and Clostridium. Additionally, significant correlations were observed between PD-associated microbes and metabolites, such as sphingomyelin and phospholipids. Importantly, PDPC significantly reduced in both PD monkey feces and serum, exhibiting strong correlation with PD-associated genes and microbes, such as SLC5A3 and Butyrivibrio species. Moreover, such multi-omic differential biomarkers were linked to the clinical rating scales of PD monkeys. Our findings provided novel insights into understanding the potential role of key metabolites in the host-microbiota interaction involved in PD pathogenesis
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
Epidemiological analysis of host populations with widespread sub-patent infections: African trypanosomiasis
Full text linkThe epidemiological study of pathogens largely depends on three technologies,
serology, microscopy and the polymerase chain reaction (PCR). Serological
methods are unable to differentiate between current and past infections.
Microscopy has historically been the mainstay of epidemiological study. In
recent times the use of microscopy has been in decline, as it has been shown to
have an inherent lack of sensitivity and specificity and produces many false
negative results. PCR is now the method of choice for screening samples for the
presence or absence of pathogens. Although PCR is widely regarded as an
extremely sensitive technique, the fact that it assays a very small volume of
sample is often overlooked. If the target pathogen is not present in the tiny
aliquot of sample from an infected host, then a false negative results will occur.
In endemic situations were the pathogen is present at low infection intensities,
then the potential for false negatives results of this type is high. This intensity
related false negative effect can lead to serious underestimation of diagnosed
prevalence and incidence with consequent misinterpretation of the resulting
data. This phenomenon has been reported in the literature for a range of
pathogens and especially for epidemiological study of schistosomiasis. The
extensive occurrence of false negatives during study of schistosomiasis
samples was such an obstacle to epidemiological study it prompted the world
health organisation to repeatedly call for quantitative methods to be employed to
combat the problem.
The main objectives of this thesis are to rationalise and simplify the methods of
diagnosing African trypanosomes in epidemiological studies and to investigate
the consequences of, and methods of dealing with infection intensity related
false negative results that occur as a result of widespread sub-patent infections
in the study population
A new PCR assay was developed that was capable of analysing whole blood
placed onto treated filter paper. The PCR assay was capable of differentiating
between all the important African trypanosome species, producing a unique size
of amplicon for each species of trypanosome. Initial results from repeated
screening of human and cattle samples known to be parasitologically positive
indicated that many false negative results occur. A more extensive analysis of
thirty five bovine blood samples randomly chosen from a collection of field
samples revealed that false negative results occurred regularly. The prevalence of infection after a single screening was 14.3% whereas the cumulative
prevalence after over 100 repeated screenings rose to 85.7%. This showed that
a severe underestimation of prevalence occurs from a single screening of the
samples.
In order to investigate the consequences of, and develop methods of dealing
with this problem, computer based simulations were used to model the
dynamics of screening samples with sub-patent infections. In order to construct
the model the data obtained from repeat screening of the thirty-five bovine blood
samples was fitted to a number of mathematical distributions. A negative
binomial distribution best described the distribution of trypanosomes across the
hosts. Exploration of the phenomenon with the resulting model showed the
extensive underestimation of true prevalence that is possible. The simulations
also showed that it is possible for populations with very different patterns of
infection and true prevalence to all have the same diagnosed prevalence from a
single screening per sample. Statistical comparison of these very different
populations by diagnosed prevalence alone would conclude there was no
significant difference between the populations. It was therefore concluded that
the diagnosed prevalence from a single (or even multiple) screenings is an
inadequate and potentially misleading measure of both infected hosts and
parasite numbers.
In order to deal with these problems new methods were evaluated for use in
epidemiological studies. A simple method of producing quantitative measures of
infection was advocated. The insensitivity of existing screening methods in
detecting significant difference between populations was highlighted and a
greatly improved methodology was shown. Finally, a method for inferring the
true population prevalence from the data obtained from repeat screening of
samples was suggested. Although some of these new methodologies have
limitations, they represent a great improvement on the use of a single diagnostic
test for each host. The work presented in this thesis highlights a serious
potential limitation to our understanding of the epidemiology of pathogens that
exist at sub-patent levels, and develops some possible methods of overcoming
these limitations
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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