1,720,992 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
Coccolithophorid biogeography in the Gulf of Manfredonia (South Adriatic Sea): preliminary results from water samples and surface sediments.
No full textCoccolithophore communities in the Gulf of Manfredonia (Southern Adriatic Sea): data from water and surface sediments
No full textLiving coccolithophore distributions from the Gulf of Manfredonia (Southern Adriatic Sea) were investigated and comparedwith
the coccolith assemblages in the underlying surface sediments. In total, 55 samples from 13 stations in four transects collected
at the end of October 2000 were analyzed to determine spatial and vertical distribution of individual taxa in the coastal environment. At
all stations, the maximum coccosphere densities were between 10m and 30m of water depth (maximum values were ~4x104
coccospheres per litre of seawater). Coccolithophore absolute abundances show a vertical stratification and spatial variation, as well as
variable species diversity, increasing from the coast to the open sea and decreasing with depth. Different coccolithophore communities
are recorded in the shallow and deep photic zone. Emiliania huxleyi, Syracosphaera spp., Rhabdosphaera spp., Coronosphaera spp.,
Umbellosphaera tenuis and holococcolithophores are present mainly in the surface waters, above the thermocline between 25-30m
depth. In the deeper water samples, there is a significant increase in coccospheres of Florisphaera profunda. The coccolithophore cell
density variability is compared with in situ measurements of environmental parameters (temperature, salinity, nitrates and phosphates).
Cell densities of all dominant taxa are most highly correlated with temperature variability. The low correlations of cell densities with nitrates
and phosphates may be caused by insufficient sampling resolution, nutrient levels close to detection limits, or both. The comparison
of the living assemblage with surface sediment records shows significant differences in the presence and abundance of some species.
The recognised fossil record in the surface sediments ismainly represented by Cretaceous-Pleistocene reworked species, showing stronger
dynamic processes at the bottom, such as terrigenous input and resuspension, than phytoplankton growth. Most marked correspondence
between living and fossil assemblages has been found in the deeper and open sea sediment
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
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
microRNAs as biomarkers of oxidant/antioxidant status
No full textThe discovery of small non-coding RNA (sncRNA) has generated enormous interest in their use as potential biomarkers
and as new drugs targeting genes. These molecules are involved in gene expression regulation: they are able to regulate
gene expression mainly by base-pairing to the 3'-UTR of specific target mRNAs so controlling, at epigenetic level, a wide
range of biological processes. MicroRNAs (miRNAs), a class of sncRNAs, are single stranded non-coding RNA ~19-25 nt
in length, that are transcribed from intergenic and intronic sequences and are released also in extracellular compartment
carried by various proteins, lipids and by exosomes, spreading in this way, molecular signals in biological fluids from one
district to others. Therefore, miRNAs may represent a fine-tuning of signaling able to reach different body districts and to
integrate multiple inputs and outputs. This makes them suitable to be used both as markers of disease state and as new
drugs for the control of protein expression (i.e. oncogenes). The discovery that circulating miRNAs are measurable in
serum and plasma and in other biological fluids and that their expression varies in the presence of pathologies makes them
of great potential in diagnostic applications.
Many epidemiological studies correlate the beneficial effects on population health to food containing polyphenols with the
antioxidant property of these molecules, but there are still unclear points regarding the useful concentrations. For example
the influence on gene transcription and gene regulation is far to be elucidated. Some recent studies have shown that
polyphenols are able to influence gene expression at the epigenetic level inducing the transcription of sncRNAs, in
particular miRNAs, that are able to inhibit the expression of target genes by interfering with the translation of their RNA
messengers (Bartel, 2004).
In our study we aimed to investigate, in the human intestinal Caco-2 cell line, if different concentrations of the polyphenol
Gallic Acid (GA) can modulate differently mithocondrial antioxidant activities by inducing different levels of miRNA
which down-regulate Mn SOD, Catalase and Peroxidase enzimes. In addition, cell proliferation (mitotic index) and death
(MTT test) were evaluated. Total RNA was obtained both from cells and culture media of untreated and treated cultures
and quantitative real-time PCR (qRT-PCR) of several miRNAs (mir-17-3p, mir-21-5p, mir-421) was performed using
cDNA obtained following the reverse transcription reaction with the miRCURY LNATM Universal RT micro RNA PCR
kit. From our results GA treatment induces a modulation of different miRNAs that, in turn, influences a number of
different biological processes. The modulation of miRNA synthesis was confirmed in culture medium. Our results
demonstrated a dose-dependent miRNA expression with a progressive increasing in miRNA levels that down regulate
mitochondrial antioxidant activity (mir-17-3p), cell proliferation (mir-21) and damage repair (mir-421). The progressive
increase in miRNA levels correlate with a progressive increase in toxic effects of GA. Our results are in agreement with
other studies showing that polyphenols are able to modulate miRNA synthesis (Bartel, 2004) and suggest the need of
further research for a safe use of antioxidant supplements in the light of the complex miRNA network interactions to avoid
possible adverse effects.
Bartel (2004). Cell 116: 281-97
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