1,721,024 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
Bifidobacterial occurrence in in cotton-top tamarin (Saguinus oedipus) and emperor tamarin (Saguinus imperator)
No full textUnlike in humans, the diversity of bifidobacteria in the gut of non-human primates is poorly understood. In the present work, for the first time, the bifidobacterial population in cotton-top tamarin (Saguinus oedipus) and in emperor tamarin (Saguinus imperator) has been studied. The main objective of this study was the isolation and the identification of bifidobacterial strains from one adult subject of the cotton-top tamarin and from one adult subject of the emperor tamarin. The analysis of their bifidobacterial communities by molecular methods was assessed by culture dependent and culture independent techniques. Viable bifidobacteria ranging from 8 to 9.0 log10/g of faeces were found in both tamarins and sixty-three fructose-6-phosphate phosphoketolase positive strains were isolated and characterized. Rep PCR analysis with primer BOXA1R clustered these isolates in fifteen different groups. The 16S rRNA gene sequence analysis confirmed the presence of 15 different Clusters (nine Clusters for each tamarin) and six out of them were species previously described in
other Callitrichidae (common marmoset): Bifidobacterium callithricos (Cluster V), Bifidobacterium stellenboshense (Cluster VIII), Bifidobacterium myosotis (Cluster X), Bifidobacterium biavatii (Cluster XII), Bifidobacterium tissieri (Cluster XIII) and Bifidobacterium catulorum (Cluster XIV). The remaining nine Clusters represent new species. Recently 4 clusters have been described as the novel species Bifidobacterium aerophilum (Cluster I), Bifidobacterium avesanii (Cluster II), Bifidobacterium ramosum (Cluster III) and Bifidobacterium callitrichidarum (Cluster XI). Clusters IV, VI, VII and IX are new species under description and Cluster XV is a new species under study. These new species show phenotypic similar features such as microaerophilic growth. Based on our results, bifidobacteria could be considered natural inhabitants of the gut of the cotton-top tamarin and emperor tamarin. An interesting finding is the high number of
bifidobacterial clusters found in every single tamarin showing a high intra/inter-subjects diversity and similarity: this is in contrast with the few numbers of species (at maximum 4) usually found per human host. Interestingly, comparing data on studies of bifidobacterial distribution in New World Monkeys (common marmoset and tamarins), it can be observed that some bifidobacterial species were exclusively present in Common marmosets or tamarins, whereas other species were widely shared across all these Callitrichidae. Consequently, such complex and heterogeneous bifidobacterial communities seem to be composed of some bifidobacterial species more intimately close to their host (probably being genetically adapted to the host) and a core of species potentially shared across different host species, which reflect the co-evolution of these beneficial microorganisms with their host
NON-HUMAN PRIMATES BIFIDOBACTERIACEAE: A RESERVOIR FOR APPLICATION FOR ANIMAL WELL-BEING
No full textAfter discover of bifidobacteria in human infant from H. Tissier in 1900, Bifidobacteriaceae microorganisms have been extensively studied mostly in the gastrointestinal tracts of human and other animals both from ecological and practical application point of view. Their importance is mainly related to their strict link with human and animal health due to many probiotic features such as modulation of immune system, antagonistic activity towards pathogens, alleviation of lactose intolerance, production of useful metabolites. Recently the BoCC-BUSCoB (Bologna Culture Collection - Bologna University Scardovi Collection of Bifidobacteria) has extensively studied the presence of bifidobacteria in non-human primates. Bifidobacteriaceae new species have been isolated from old world monkeys (Lemur catta and Eulemuris macaco), new world monkeys (Callithrix jacchus, Saguinus oedipus, Saguinus imperator, Terophitecus gelada) and hominidis (orangutan and chimpanzee). The study of non-human primates “probiotic microbiota”, where bifidobacteria represent one of the most important probiotic group, is very important especially in the view of their application for the well-being of animals in controlled environment. The exploitation of probiotic properties of strains isolated from non-human primates requires the existence of isolates in culture collections, which assure the maintenance with appropriate methodologies of bifidobacterial cultures for intended health and biotechnological uses
A FIRST INSIGHT INTO GASTROINTESTINAL MICROBIOTA OF THE SEYCHELLES GIANT TORTOISES
No full textAll animals possess a complex microbiome, defined as the collection of microorganisms colonizing the body, and their genetic material. Microbiome play a fundamental role in many physiological processes and in host health and diseases. Studies on gut microbiomes of different animals have provided a wealth of ecological and evolutionary information showing a strict link with health and disease conditions. However, very few studies have been devoted to herbivorous reptiles. The aim of the present work was the analysis of microbiota gastrointestinal community of Aldabrachelys gigantean, herbivorous giant tortoises both living at Seychelles and at Parco Natura Viva Zoological Park in Verona (Italy) to characterize a gut microbial biodiversity which could be utilized as marker of good health. Young and adult individual Giant tortoises (13 from Seychelles and 11 from Parco Natura) were enrolled. Faecal swabs were obtained from each individual. Different selective medium was utilized to show beneficial bacteria such as lactic acid bacteria and bifidobacteria presence. Moreover, a molecular analysis of faecal microbiota by means of Illumina platform is under progress. DNA were extracted from all samples by Qiagen faecal DNA kit. The amplification of the V3-V4region of 16S rRNA has been performed. Amplicons were obtained from all samples except 4 samples from Seychelles tortoises due to low amount of DNA. These amplicons are under sequencing. For what concerns isolation unfortunately even if six different specific selective media have been utilized no lactic acid bacteria and bifidobacteria isolates have been obtained. Otherwise the genus specific
PCR for bifidobacteria showed that samples with DNA good quality are positive for the presence of this genus. Other study will be performed in order to obtain a selective medium appropriate for the isolation of bifidobacteria. The difficulty of cultivating bifidobacteria indicate that the role of bifidobacteria in Seychelles turtles could be underestimated
Assessment of Biolog EcoplateTM method for functional metabolic diversity of aerotolerant pig fecal microbiota
Full text linkIn the last decades, gut microbiota and its role in mammal host development and health have been increasingly investigated. Metabolites produced by gut microbiota can affect intestinal homeostasis and immune system maturity and activation, and in turn, they can influence the health and growth performance of livestock. Therefore, a better understanding of the functional metabolic capability of the gut microbiota would be appreciated by the scientific community. In this study, the BiologTM Ecoplates technology was applied for studying the metabolic potential of the aerotolerant microbial community of pig fecal samples, evaluating the interference of different storage conditions and cell concentrations. The length of time for which a fecal sample maintained detectable and unchanged microbial metabolic activity was also investigated. Two assays aimed to evaluate differences in the metabolic activities between fresh and snap-frozen fecal samples at different dilutions and at different lengths of times of preservation at −80°C were carried out. The biodiversity and the predicted functionality of the entire bacterial community through a targeted metagenomic approach were also explored. The results highlighted that snap freezing of fecal samples preserved the metabolic activity of the microbial community when compared to fresh feces. Sample storage at −80 °C did not significantly affect the metabolic activity of the microbial community, which was stable for 150 days. Furthermore, the highest metabolic activity was detected with 1:2 to 1:5 dilutions of the stock suspension. BiologTM Ecoplates technology is a rapid and useful method to explore microbial communities’ metabolism in animal fecal samples contributing to investigate host animal physiology
Monarda fistulosa L. hydrolate as antimicrobial agent in artificial media for the in vitro rearing of the tachinid parasitoid Exorista larvarum (L.)
No full textExorista larvarum (L.) (Diptera Tachinidae), a larval parasitoid of Lepidoptera, can be reared in vitro from egg to fecund adult on artificial media composed of crude components. The standard in vitro culture is performed in 24-well plastic rearing plates. Exorista larvarum eggs, removed from superparasitized larvae of Galleria mellonella (L.) (Lepidoptera Pyralidae), are individually placed in the wells, each containing a cotton ball soaked in liquid medium. The plates are then sealed until parasitoid puparium formation. Newly-formed puparia are collected from the medium and transferred into cages for adult emergence.
To avoid contamination by microorganisms, the artificial medium is routinely added with 1% solution of gentamicin. Concern over occurrence of resistant microorganisms, following the prolonged use of this broad spectrum antibiotic, has prompted research on more natural antimicrobial agents. Experiments were carried out to assess whether gentamicin may be replaced with hydrolate of the wild bergamot Monarda fistulosa L. (Lamiaceae), which was selected due to its high activity against pathogenic microorganisms for humans and plants. The hydrolate was either added to the artificial medium (0.01% w/w) (first trial), or placed in an empty well of the rearing plate (0.5% w/w), to be supplied in the aerosol form due to evaporation (second trial). In both trials, a standard medium with gentamicin and an antimicrobial-free medium were maintained as positive and negative controls, respectively. In the first trial, E. larvarum development from the egg to the adult stage in the hydrolate-added medium was comparable to that observed in the standard medium. No significant difference was found between the number of eggs laid by the females obtained in either substrate. In the second trial, however, the hydrolate in the aerosol form significantly decreased E. larvarum egg hatching, puparium formation and female fecundity compared to the standard medium. In both trials, little parasitoid development occurred in the antimicrobial-free media. The results suggest that artificial media added with M. fistulosa hydrolate solution may be competitive with those containing gentamicin for the in vitro rearing of E. larvarum. The hydrolate aerosol form was shown, instead, unsuitable
Crop Factors Influencing Ethanol Production from Sorghum Juice and Bagasse
Full text linkThis study investigated the effects of two soil moisture levels (SM) (30% and 70% soil available water) and three harvests (90 days, 118 days, and 151 days after seeding) on sweet (S506) and fiber (B133) sorghum genotypes under rain-sheltered conditions. Juice and bagasse-derived ethanol and their sum (EtOHBJ, EtOHB, and EtOHJ+B, respectively) were assessed. Water use efficiency (WUE) was determined for sorghum dry weight (DW) and EtOHJ+B. S506 had similar DW, but higher sugar content than B133, resulting in higher EtOHJ (+32%) and EtOHJ+B (+9%). High SM-enhanced DW, juice and sugars content, determining a strong EtOHJ+B increase (+99% vs. low SM). Late harvest enhanced DW and EtOHJ+B (+107% vs. early harvest), despite decreasing extractives and increasing structural fiber components. Water use efficiency of EtOHJ+B improved with high vs. low SM, although differences faded in late harvest. Upscale of EtOHJ+B and WUE data indicated a range of 21,000–82,000 ha of sorghum cultivation and 60–117 Mm3 of irrigation water, as amounts of resources needed to supply an 85,000 m3·yr−1 bio-ethanol plant. This large variation in land and water needs depended on specific combinations between crop factors SM and harvests
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