1,720,970 research outputs found
Treponema pallidum Cytoplasmic filament protein gene partial sequence
No full textA partial sequence of the Cytoplasmic filament protein gene (cfpA) of treponema pallidum from non human primates</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Leprosy in wild chimpanzees
No full textAbstract
Humans are considered as the main host for
Mycobacterium leprae
1
, the aetiological agent of leprosy, but spillover has occurred to other mammals that are now maintenance hosts, such as nine-banded armadillos and red squirrels
2,3
. Although naturally acquired leprosy has also been described in captive nonhuman primates
4–7
, the exact origins of infection remain unclear. Here we describe leprosy-like lesions in two wild populations of western chimpanzees (
Pan troglodytes verus
) in Cantanhez National Park, Guinea-Bissau and Taï National Park, Côte d’Ivoire, West Africa. Longitudinal monitoring of both populations revealed the progression of disease symptoms compatible with advanced leprosy. Screening of faecal and necropsy samples confirmed the presence of
M. leprae
as the causative agent at each site and phylogenomic comparisons with other strains from humans and other animals show that the chimpanzee strains belong to different and rare genotypes (4N/O and 2F). These findings suggest that
M. leprae
may be circulating in more wild animals than suspected, either as a result of exposure to humans or other unknown environmental sources
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Yaws Disease Caused by Treponema pallidum subspecies pertenue in Wild Chimpanzee, Guinea, 2019
No full textGenomik infektiöser bakterieller Hauterkrankungen bei wilden nichtmenschlichen Primaten: Gieren und Lepra
No full textYaws-like disease in non-human primates (NHPs) caused by Treponema pallidum subsp. pertenue (TPE) has been largely reported in sub-Saharan Africa with diverse dermatological manifestations. However, it remained unclear how the genomic diversity of TPE lineages that do occur in NHPs is distributed across hosts and space. In Taï National Park (TNP), Côte d’Ivoire, symptomatic Cercocebus atys monkeys were observed to have yaws- and syphilislike lesions. The present study investigated the TPE diversity in wild NHPs in TNP and other sites where the disease occurs in sub-Saharan Africa.
Phylogenomic analyses from this study revealed that dermatological pathology observed among sooty mangabeys in TNP were caused by a large diversity of TPE lineages. All TPE genomes determined from these sooty mangabeys were different and exhibited divergence levels not observed in other field sites where the disease seems to be epizootic. The results presented in this dissertation, do not support the epizootic spread of a single TPE clone at TNP, but rather points towards frequent independent introductions of the bacterium, which can cause orofacial and genital-like lesions within a single social group of Cercocebus atys monkeys. Besides, simian TPE isolates determined in this study and those available in the public domain, did not form monophyletic clades based on host species or the type of symptoms caused by an isolate, but rather clustered based on geography. This phylogenetic pattern is compatible with cross-species transmission of TPE within ecosystems where this disease occurs, though it remains unclear how often and by what means this transmission occurs. This study now lays basis for future studies on the potential occurrence of TPE transmission among different NHP species and future studies should aim to reveal transmission pathways of TPE in NHP habitats.
This work also demonstrates that informative TPE genomic data can be obtained from old NHPs bones collected from endemic areas; helping to trace the disease back into the past as well as identify new sites that might be affected by the disease where no clinical cases are currently observed. Thus, using bone derived TPE short sequences coupled with phylogenetic read placement algorithm, this study showed that TPE infected NHPs in TNP for at least three decades ago, complementing clinical evidence which only started accumulating from 2014. Additionally, detection of TPE in field sites were no clinical cases are observed indicates that TPE infections in NHPs are underreported, warranting the intensive surveillance of the disease in wild NHPs.
In the second part, this study aimed to investigate the causative agent of leprosy-like symptoms observed in NHPs in both Cantanhez National Park and Täi National Park. The investigations involved adapting a suitable non-invasive screening tool to facilitate the determination and characterisation of the causative agent of the observed skin lesions.
Using faecal samples, this study determined that M. leprae was the cause of the leprosy- like lesions confirming the first ever observed sylvatic leprosy cases among NHPs in West Africa. This finding shows that faecal samples of NHP that are easily collected, can be used for surveillance of leprosy in wild NHPs and have the potential for scalability in terms of screening huge populations over large areas. Further, this study also presents sequence data highlighting that wild chimpanzees are infected with two genotypes of Mycobacterium leprae that are rare in human populations i.e. 4N/O and 2F and could potentially serve as reservoir hosts of these rare genotypes. For the first time, genotype 2F of M. leprae that circulated mostly in the medieval time in Europe was detected in West Africa. The detection of 2F in a region dominated by genotype 4 M. leprae strains questions the current understanding that the infection in NHPs was a result of a human strains spill overs. Finally, it is now evident that M. leprae is not only a human pathogen since red squirrels, armadillos and NHPs are also naturally infected. Therefore, investigations into the role these animal reservoir hosts play in the ecology of leprosy disease might be useful in informing strategies on the ongoing leprosy eradication campaign by WHO.Es gibt eine vielzahl von Berichten über eine gierartige Krankheit bei nicht-menschlichen Primaten (NHPs), die durch Treponema pallidum subsp. pertenue (TPE) verursacht wird und in ihren verschiedenen dermatologischen Ausprägungen aus weiten Teilen der Subsahararegion Afrikas. Es blieb jedoch bislang unklar wie die genomische Vielfalt der NHPspezifischen TPE-Linien über Wirte und Raum verteilt ist. Im Taï-Nationalpark (TNP), Côte d'Ivoire, wurden symptomatische Rußmangaben (Cercocebus atys atys atys) mit gier- und syphilisähnlichen Läsionen beobachtet. Im Zusammenhang dazu untersucht die vorliegende Studie die Diversität von TPE bei wilden NHPs in TNP und anderen Standorten, an denen die Krankheit in Subsahara-Afrika auch zuvor aufgetreteten is.
Phylogenomische Analysen aus dieser Studie zeigten, dass das dermatologische Krankheitsbild von Rußmangaben in TNP, durch eine große Vielfalt von TPE-Linien verursacht wird. Alle TPE-Genome, die aus dieser Mangabenart isoliert werden konnten, waren unterschiedlich und zeigten deutlich andere Divergenzniveaus als bisher für eine einzige Spezies an einem Feldforschungsort, an dem die Krankheit vermutlich epizootisch ist, beobachtet werden konnte. Die in dieser Arbeit vorgestellten Ergebnisse unterstützen nicht die epizootische Ausbreitung eines einzelnen TPE-Klons, sondern weisen stattdessen auf häufige unabhängige Einführungen des Bakteriums hin, die syphilis- und gierähnliche Läsionen innerhalb einer einzigen sozialen Gruppe von Rußmangaben verursachen können. Desweiteren bilden die in dieser Studie bearbeiteten Isolate von simianem TPE keine monophyletischen Kladen mit den bislang veröffentlichten Vergleichsgenomen auf der Grundlage ihrer Wirtsarten oder Art der Symptome, sondern in Bezug auf ihre Geographie. Dieses phylogenetische Muster ist einhergehend mit der artenübergreifenden Übertragung von TPE in denjenigen Ökosystemen, in denen die Krankheit auftritt. Es bleibt allerdings unklar, wie oft und auf welche Weise diese Übertragung stattfindet. Diese Studie bildet nun die Grundlage für zukünftige Studien über das mögliche Auftreten der TPE-Übertragung bei NHPs.
Diese Arbeit zeigt auch, dass wertvolle TPE Genomdaten aus alten NHP-Knochen aus endemischen Gebieten gewonnen werden können. Dies kann helfen die Krankheit in die Vergangenheit zurückverfolgen und neue Standorte zu identifizieren, die in der Gegenwart oder Zukunft von der Krankheit betroffen sein könnten, auch wenn zum jetzigen Zeitpunkt keine klinischen Fälle bekannt sind. So zeigte diese Studie unter Verwendung von knochenabgeleiteten TPE-Kurzsequenzen in Verbindung mit einem phylogenetischen Leseplatzierungsalgorithmus , dass TPE in TNP für mindestens drei Jahrzehnte NHPs infiziert hat und ergänzt damit klinische Beweise, die sich erst ab 2014 zu sammeln begannen. Darüber hinaus zeigt der Nachweis von TPE in Freilandanlagen, in denen offiziell keine klinischen Fälle beobachtet werden, dass TPE-Infektionen in NHPs weitgehend unbemerkt bleiben, was eine intensive Überwachung der Krankheit bei wilden NHPs rechtfertigt.
Im zweiten Teil zielte diese Studie darauf ab, den Erreger lepraähnlicher Symptome zu untersuchen, die bei NHPs im Cantanhez Nationalpark und im Täi Nationalpark beobachtet wurden. Die Untersuchungen umfassten die Anpassung eines geeigneten nicht-invasiven Screeningtools, um die Bestimmung und Charakterisierung des Erregers der beobachteten Hautläsionen zu erleichtern.
Anhand von Stuhlproben konnte in dieser Studie festgestellt werden, dass M. leprae die Ursache für die lepraähnlichen Läsionen war und somit die ersten jemals beobachteten sylvatischen Leprafälle bei NHPs in Westafrika bestätigten. Dieses Ergebnis zeigt, dass Fäkalproben von NHP, die ohne große Schwierigkeiten gesammelt werden können, zur Überwachung der Lepra bei wilden NHPs verwendet werden können und das Potenzial für Skalierbarkeit beim Screening großer Populationen über große Gebiete haben. Darüber hinaus stellt diese Studie auch Sequenzdaten vor, die zeigen, dass wilde Schimpansen mit zwei Genotypen von Mycobacterium leprae infiziert sind, die in menschlichen Populationen selten sind. Dabei handelt es sich um 4O-P und 2F, und somit besteht die Möglichkeit, dass Schimpansen als Reservoirwirte dieser seltenen Genotypen dienen könnten. Zum ersten Mal wurde in Westafrika der Genotyp 2F von M. leprae entdeckt, der hauptsächlich im Mittelalter in Europa zirkulierte. Der Nachweis von 2F in einer Region, die vom Genotype 4 M. leprae dominiert wird, stellt das aktuelle Verständnis in Frage, dass die Infektion in NHPs das Ergebnis einer Übertragung vom Menschen waren. Abschließend ist inzwischen evident, dass M. leprae nicht nur ein menschlicher Erreger ist, da auch rote Eichhörnchen, Gürteltiere und NHPs auf natürlichem Wege infiziert werden können. Somit könnten Untersuchungen über die Rolle dieser Tiere als Reservoirwirte bei der Ökologie der Leprakrankheit nützlich sein, um Strategien für die Leprabekämpfung zu entwickeln
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