1,721,009 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
Transverse myelitis spectrum disorders
No full textAcute transverse myelitis (ATM) is an inflammatory demyelinating
disorder that affects the spinal cord focally resulting in motor
sensory and autonomic dysfunction. Establishing the diagnosis of ATM is
not as difficult as determining the possible etiology. There is a
difference in the perception of ATM seen in the West as compared to
developing countries. In the West multiple sclerosis (MS) is the most
common inflammatory disorder of the central nervous system. An attack
of ATM may be the beginning of MS. However, this may not be the case in
developing countries where MS is uncommon. Most often transverse
myelitis is monophasic and at best represents a site-restricted form of
acute disseminated encephalomyelitis (ADEM). Traditionally the
combination of optic neuritis and ATM, occurring as a monophasic
illness would have been called as neuromyelitis optica (NMO). Changing
concepts in the definition of NMO and the discovery of a biomarker,
neuromyelitis optica immunoglobulin (NMO_IgG), has changed the way
relapsing autoimmune disorders are being perceived currently. A variety
of idiopathic inflammatory disorders such as Japanese form of optic
spinal MS, recurrent myelitis, and recurrent optic neuritis have been
brought under the umbrella of neuromyelitis spectrum disorders because
of the association with NMO-IgG. Complete transverse myelitis
accompanied by longitudinally extensive transverse myelitis which is
seronegative for this biomarker has also been reported from several
countries including Japan, Australia, and India. Thus, ATM is a
heterogeneous disorder with a varied clinical spectrum, etiology, and
outcome
Differential diagnosis of white matter diseases in the tropics: An overview
No full textIn hospitals in the tropics, the availability of magnetic resonance imaging (MRI) facilities in urban areas and especially in teaching institutions have resulted in white matter diseases being frequently reported in a variety of clinical settings. Unlike the west where multiple sclerosis (MS) is the commonest white matter disease encountered, in the tropics, there are myriad causes for the same. Infectious and post infectious disorders probably account for the vast majority of these diseases. Human immunodeficiency virus (HIV) infection tops the list of infective conditions. Central nervous system (CNS) tuberculosis occasionally presents with patchy parenchymal lesions unaccompanied by meningeal involvement. Human T cell leukemia virus (HTLV) infection and cystic inflammatory lesions such as neurocysticercosis are important causes to be considered in the differential diagnosis. Diagnosing post infectious demyelinating disorders is equally challenging since more than a third of cases seen in the tropics do not present with history of past infection or vaccinations. Metabolic and deficiency disorders such as Wernicke′s encephalopathy, osmotic demyelinating syndrome associated with extra pontine lesions and Vitamin B12 deficiency states can occassionaly cause confusion in diagnosis. This review considers a few important disorders which manifest with white matter changes on MRI and create diagnostic difficulties in a population in the tropics
16S rRNA sequences of gut microbiome and meta data
No full textObjective:To understand the role of gut microbiome in influencing the pathogenesis of neuromyelitis optica spectrum disorders (NMOSD)among patients of south Indian origin.
Methods:In this case control study, stool and blood samples were collected from 39 NMOSD patients, including 17 with aquaporin 4 IgG antibodies (AQP4+) and 36 matched controls. 16S rRNA sequencing was used to investigate the gut microbiome. Peripheral CD4+ T cells were sorted in 12 healthy controls & 12 AQP4+NMOSD patients, RNA extracted, and immune gene expression analyzed using Nanostring nCounter human immunology kit code set.
Results: Microbiota community structure (beta-diversity) differed between AQP4+ NMOSD and healthy controls (p <0.001, pairwise PERMANOVA test). Linear discriminatory analysis effect size (LEfSe) identified several members of the microbiota that were altered in NMOSD patients, including an increase in Clostridium bolteae (effect size 4.23, pvalue 0.00007). C.bolteae was significantly more prevalent (p=0.02) amongAQP4-IgG + NMOSD (n= 8/17 subjects)compared to seronegative patients (n= 3/22) and was absent among healthy stool samples.C bolteae has a highly conserved glycerol uptake facilitator and related aquaporin protein(p59-71) that shares sequence homology with AQP4 peptide(p92-104), positioned within an immunodominant (AQP4specific)T cell epitope (p91-110).Presence of C. bolteae correlated with expression of inflammatory genes associated with both innate and adaptive immunity and particularly involved in plasma cell differentiation ,B cell chemotaxis and Th17 activation.
Conclusion: Our study described elevated levels of C. bolteae associated with AQP4+ NMOSD among Indian patients. It is possible that this organism may be causally related to the immunopathogenesis of this disease in susceptible individuals.
Objective:To understand the role of gut microbiome in influencing the pathogenesis of neuromyelitis optica spectrum disorders (NMOSD)among patients of south Indian origin.
Methods:In this case control study, stool and blood samples were collected from 39 NMOSD patients, including 17 with aquaporin 4 IgG antibodies (AQP4+) and 36 matched controls. 16S rRNA sequencing was used to investigate the gut microbiome. Peripheral CD4+ T cells were sorted in 12 healthy controls & 12 AQP4+NMOSD patients, RNA extracted, and immune gene expression analyzed using Nanostring nCounter human immunology kit code set.
Results: Microbiota community structure (beta-diversity) differed between AQP4+ NMOSD and healthy controls (p <0.001, pairwise PERMANOVA test). Linear discriminatory analysis effect size (LEfSe) identified several members of the microbiota that were altered in NMOSD patients, including an increase in Clostridium bolteae (effect size 4.23, pvalue 0.00007). C.bolteae was significantly more prevalent (p=0.02) amongAQP4-IgG + NMOSD (n= 8/17 subjects)compared to seronegative patients (n= 3/22) and was absent among healthy stool samples.C bolteae has a highly conserved glycerol uptake facilitator and related aquaporin protein(p59-71) that shares sequence homology with AQP4 peptide(p92-104), positioned within an immunodominant (AQP4specific)T cell epitope (p91-110).Presence of C. bolteae correlated with expression of inflammatory genes associated with both innate and adaptive immunity and particularly involved in plasma cell differentiation ,B cell chemotaxis and Th17 activation.
Conclusion: Our study described elevated levels of C. bolteae associated with AQP4+ NMOSD among Indian patients. It is possible that this organism may be causally related to the immunopathogenesis of this disease in susceptible individuals.Is identical to PRJNA662563Seventeen AQP4 IgG positive (AQP4+) NMOSD patients,22 AQP4-IgG negative (AQP4-) patients and 36 healthy volunteers matched for age and body mass index (BMI) were included from our registry.Stool samples were collected in containers provided to patients. They were delivered in person or by relative on the same day of collection over a median period of 3hours (range: 1-5 hours).Stool samples were then immediately frozen at –80 ο C until DNA extraction.
16S rRNA sequencing of the gut microbiota
DNA was extracted from stool using QIAamp® DNA Stool extraction kit as per the manufacturer's instructions. DNA was transported in dry ice from Nitte University to Brigham &Women's Hospital,Boston, USA for further analysis. Samples were normalized and bacterial 16S rRNA gene was amplified using primers for amplification of V4 region as per protocols described in the Earth Microbiome Project14.Samples were sequenced by paired end 250base pair reads at the Harvard Medical School Biopolymer facility using Illumina MiSeq platform. FastQC program (www.bio informatics.babraham.ac.uk/projects /fastqc/)was used to evaluate sequence quality.We used QIIME2 (Qualitative Insights into microbial Ecology), an open source bioinformatics platform, for downstream analysis8. Sequences were de-multiplexed and de-noised using DADA2. Taxonomy was assigned using reference database SILVA (https://www.arb-silva.de). In addition, we used EZ-Taxon (www.EzTaxon.org) to identify some species that could not be annotated by SILVA.Alpha-diversity was calculated using Faith's phylogenetic diversity (PD), observed (operational taxonomic unit (OTUs) and Shannon diversity metrics. Beta-diversity was calculated using weighted and unweighted UniFrac distances16.Relative abundance of individual species was calculated ( relative frequency in each sample / sum of relative frequency in all samples tested (n=75) and expressed as a percentage).
We used linear discriminant analysis (LDA) effect size (LEfSe) on the Galaxy Browser, http://huttenhower.sph.harvard.edu/galaxy to detect compositional changes in the microbiome in NMOSDpatients and controls17.Accordingly, non-parametric factorial Wilcoxon rank-sum test was usedinitially to detect bacterial taxa with significant (a set at 0.01) differential abundance in NMOSD patients vs healthy controls.Then, estimate of the effect size of each differentially abundant feature was calculated using LDA, with a cutoff greater than 3
Transverse myelitis spectrum disorders
Full text linkAcute transverse myelitis (ATM) is an inflammatory demyelinating
disorder that affects the spinal cord focally resulting in motor
sensory and autonomic dysfunction. Establishing the diagnosis of ATM is
not as difficult as determining the possible etiology. There is a
difference in the perception of ATM seen in the West as compared to
developing countries. In the West multiple sclerosis (MS) is the most
common inflammatory disorder of the central nervous system. An attack
of ATM may be the beginning of MS. However, this may not be the case in
developing countries where MS is uncommon. Most often transverse
myelitis is monophasic and at best represents a site-restricted form of
acute disseminated encephalomyelitis (ADEM). Traditionally the
combination of optic neuritis and ATM, occurring as a monophasic
illness would have been called as neuromyelitis optica (NMO). Changing
concepts in the definition of NMO and the discovery of a biomarker,
neuromyelitis optica immunoglobulin (NMO_IgG), has changed the way
relapsing autoimmune disorders are being perceived currently. A variety
of idiopathic inflammatory disorders such as Japanese form of optic
spinal MS, recurrent myelitis, and recurrent optic neuritis have been
brought under the umbrella of neuromyelitis spectrum disorders because
of the association with NMO-IgG. Complete transverse myelitis
accompanied by longitudinally extensive transverse myelitis which is
seronegative for this biomarker has also been reported from several
countries including Japan, Australia, and India. Thus, ATM is a
heterogeneous disorder with a varied clinical spectrum, etiology, and
outcome
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