1,721,065 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
Extreme environmental gradients as natural laboratories for studying microbial culturability, life cycle and evolution
No full textExtreme environments may experience strong temporal and/or spatial gradients that dramatically change the physico-chemical conditions affecting the organisms living in there. Microbial communities are the most important life form assemblages in these environments, showing a surprising ability to cope with the sharp changes, even having a selective advantage when able to enter in a survival life style mode. Gradients influence the structure, function and culturability of the associated microbiome and extreme environments showing strong changes in a short spatial/temporal interval are suitable candidates to study microbial life cycle and adaptation. Deep anoxic hypersaline brines are an important marine ecotone where microorganisms face strong meter-scale halo- and chemoclines, challenging and enhancing their biology and level of associations. Semiterrestrial mangrove crabs are important ecosystemic keystone species that are undergoing a landward evolution establishing a symbiontic relationship with bacteria that help them cope with a nitrogen poor and high salinity intertidal environment; crabs, and thus their symbionts, continually switch between air and seawater, and are exposed to salinity fluctuations, fuelling a unique and complex symbiotic community. In polar deserts, when glaciers retreat release a barren mineral substrate subjected to the processes of primary colonization, generating ‘chronosequences’, exhibiting kilometer-scale spatial gradients of ecosystem development, where microorganisms cope with different physico-chemical gradients shaping the microbial community associated with soil substrate and the pioneer plants growing there.
We propose these ecotones as model systems to explore the response of microorganisms to variable conditions which influence their life cycle, evolutionary pattern and the culturable state
Polychlorinated byphenils degradation by soil microbiota upon stimulation of root exudates.
Full text linkPhyto-rhizo-remediation is a promising technology for pollutant clean-up provided by the plant holobiont, composed by the host plant and its associated microbiome. Through root exudation, the plant nurtures and shape the structure and functionality of the microbial communities inhabiting the root system. The complex interactions between the plant host and the microbiome are poorly understood, in particular in contaminated environments where the pollution stress induces specific root exudation profiles that could have a role in the activation of the microbial degrading metabolism.
The study will be applied to the site of Brescia-Caffaro, one of the largest sites in Europe contaminated by polychlorinated biphenyls (PCBs).
The project aims to sort out the time-spatial synergistic interplay within the plant holobiont components and the geochemistry of rhizosphere micro-niches supporting microbial degradation. The research will combine the: i) set up and application of bacterial biosensors to examine topology and dynamics of activation of the PCB degradation pathways upon stimulation by identified plant root exudates; and ii) sensing the plant modulated chemical micro-habitats through microsensor/sensor devices during plant-microbe interaction under PCBs stress.
The project outcomes will provide a comprehensive understanding of the plant holobiont applied to environmental biotechnology, focusing on the the role of root exudates as boost of soil microbiome degradative potential.
Acknowledgments: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement N° 841317
Microbial ecology-based methods to characterize the bacterial communities of non-model insects
Full text linkAmong the animals of the Kingdom Animalia, insects are unparalleled for their widespread diffusion, diversity and number of occupied ecological niches. In recent years they have raised researcher interest not only because of their importance as human and agricultural pests, disease vectors and as useful breeding species (e.g. honeybee and silkworm), but also because of their suitability as animal models. It is now fully recognized that microorganisms form symbiotic relationships with insects, influencing their survival, fitness, development, mating habits and the immune system and other aspects of the biology and ecology of the insect host. Thus, any research aimed at deepening the knowledge of any given insect species (perhaps species of applied interest or species emerging as novel pests or vectors) must consider the characterization of the associated microbiome. The present review critically examines the microbiology and molecular ecology techniques that can be applied to the taxonomical and functional analysis of the microbiome of non-model insects. Our goal is to provide an overview of current approaches and methods addressing the ecology and functions of microorganisms and microbiomes associated with insects. Our focus is on operational details, aiming to provide a concise guide to currently available advanced techniques, in an effort to extend insect microbiome research beyond simple descriptions of microbial communities
Biosensing and rhizosphere – endosphere geochemical microprofiling of polychlorinated byphenils degradation by soil microbiota upon stimulation of root exudates
Full text linkIntroduction: Phyto-rhyzo-remediation is a promising technology for pollutant clean-up provided by the plant holobiont, composed by the host plant and its microbiota. Plant root exudation is modulated by the pollution stress and has a key role in the activation of the microbial degrading metabolism. Despite the well documented role of the plant holobiont in ecosystem services, the complex interactions between host and microbiome are poorly understood, in particular in contaminated environments.
Materials and Methods: The project will span metabolomics, bioengineering of microbial strains together with an original application of microsensor/sensor devices to profile the chemistry of the root microenvironments. The study will be applied to the site of Brescia-Caffaro, one of the largest sites in Europe contaminated by polychlorinated biphenyls (PCBs).
Results: The project aims to sort out the time-spatial synergistic interplay within the plant holobiont components and the geochemistry of rhizosphere micro-niches supporting microbial degradation. The research will combine the: i) set up and application of bacterial biosensors to examine topology and dynamics of activation of the PCB degradation pathways upon stimulation by identified plant root exudates; and ii) sensing the plant modulated chemical micro-habitats through microsensor/sensor devices during plant-microbe interaction under PCBs stress.
Conclusions: The project outcomes will provide a comprehensive understanding of the plant holobiont applied to environmental biotechnology, focusing on the the role of root exudates as boost of soil microbiome degradative potential.
Acknowledgments: This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement N° 841317
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
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