1,720,962 research outputs found
Correlation between unstimulated salivary flow, pH and streptococcus mutans, analysed with real time PCR, in caries-free and caries-active children
No full textAIM: Evaluate the correlations between unstimulated salivary flow, pH and level of S. mutans, analysed through real time PCR, in caries-free and caries-active children.
MATERIALS AND METHODS: Thirty healthy children were divided into 2 groups: test group (DMFT/dmft ≥ 3 and at least 1 active caries lesion) and control group (DMFT/dmft=0). Un-stimulated saliva was collected, pH was measured and S. mutans and total bacterial amount were evaluated with real-time PCR analysis.
RESULTS: Unstimulated salivary flow in the test group was significantly lower (p = 0.0269) compared to group control. The level of S. mutans was higher in the test group (p = 0.176), and an inverse correlation was recorded between total bacterial amount and un-stimulated salivary flow (p = 0.063). In the control group a positive relationship was found between total bacterial amount and S. mutans (p = 0.045) and an inverse correlation between pH and S. mutans (p = 0.088). A t-test and a linear regression analysis were performed.
CONCLUSION: A higher salivary flow and an increased salivary pH seem to represent protective factors against caries in children, while high levels of S. mutans are correlated with caries active lesions. Caries risk assessment should be performed considering all parameters involved in the development of the disease
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
The distribution of flavonoids in Helichrysum populations.
No full textThe Helichrysum genus is characterised by a high value of phenotypic variability as well as a
biochemical and phytochemical one. The therapeutic activity and the ornamental properties of
Helichrysum plant and flowers are little considered. In Italy the genus is mainly used within the
cosmetic field for its skin protection properties and in the formulation of anti-inflammatory and antiseptic
remedies; the genus could become a niche plant. Phytochemical studies on Italian populations
of Helichrysum italicum and Helichrysum litoreum have been done. Within the Asteraceae, the
flavonoids have a wide spectrum of structural diversity, so that they are used as taxonomical
markers. In Sicily the Helichrysum genus shows a noteworthy variability; some taxa have very faint
distinctive characters.
The aim of this study is to perform a qualitative screening of flavonoidic substances in order to
characterise the Sicilian populations.
The following taxa: H. siculum (Spreng.) Boiss, H. nebrodense Heldr., H. litoreum Guss., H.
scandens Guss., H. italicum (Roth) Don, H. rupestre (Raf.) DC., with var. rupestre, messerii Pign.,
errerae (Tineo) Pign., pendulum (Presl) Fiori, and H. hyblaeum Brullo have been considered. The
ethanolic extract of the capitula was TLC chromatographed. H. italicum, H. litoreum and H .
scandens showed the highest content in flavonoidic substances; kaempferol 3-glucoside was present
in eight taxa, apigenin 7-glucoside and quercetin 3-glucoside in seven taxa. Apigenine, galangin,
kaempferol were not detected in the examined extracts, while they are reported in the literature as
present in Helichrysum. A non-flavonoidic poliphenol (clorogenic acid), a triterpenoid (ursolic acid)
and a steroidic substance (beta-sitosterol) were also present. The flavonoidic substances were mainly
present within the considered populations; their distribution is a peculiar feature of the different taxa
and can contribute to the taxonomical studies on Helichrysum genus. The results evidenced that the
flavonoids can be a useful diagnostic tool for the characterisation of Sicilian germplasm
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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