1,721,060 research outputs found
Il DNA ambientale: un nuovo strumento molecolare per il monitoraggio della biodiversità presente e passata
No full textStudiare la biodiversità di una località è un’operazione molto dispendiosa sia in termini di tempo che da un punto di vista economico. Può inoltre non essere semplice campionare tutte le specie presenti e da monitorare. Da alcuni anni è stato osservato che il DNA permane nell’ambiente sotto forma di frammenti brevi, ma di dimensioni comunque utili per studiare, attraverso metodiche molecolari, la biodiversità di un dato luogo, oltre che monitorare specie di interesse e evidenziarne in modo celere l’arrivo di nuove.The study of biodiversity can be extremely costing considering both time and financial support of traveling and sampling. Furthermore, it is possible to lack some species, whose monitoring can be relevant since they are specific biomarkers. Since some years, several laboratories assessed that it is possible to collect sample of environmental DNA that can be used for the identification of the species that live (or lived) in a specific location
Are habits inherited? A possible epigenetic route from Charles Darwin to the contemporary debate.
No full textWhat is a habit? What do habitual processes and evolutionary theory have to do with each other and what is the role played by habitual processes in heredity? The main aim of this paper is to take a fresh look at Charles Darwin's use of the term “habit”: we shall analyse value and functions of this concept in Darwin's early works, particularly in his Notebooks, and compare these early views to Darwin's more mature understanding of habits in the Origin of Species; most interestingly, we shall discuss Darwin's view on habits in the light of today's theories of epigenetic inheritance, which describe how the functioning and expression of genes is modified by the environment and how these modifications are transmitted over generations. Indeed, current epigenetics seems to revive (at least to a certain extent) Darwin's early ideas on habitual processes. The young Darwin, persuaded, after his Beagle voyage, that species change over time, considered habits as one of the main agents of evolution
Preliminary study: Comparison of antioxidant activity of cannabidiol (CBD) and α-tocopherol added to refined olive and sunflower oils
Full text linkThis study evaluates the antioxidant activity of cannabidiol (CBD), added to model systems of refined olive (ROO) and sunflower (SO) oils, by measuring the peroxide value, oxidative stability index (OSI), electron spin resonance (ESR) forced oxidation, and DPPH• assays. Free acidity, a parameter of hydrolytic rancidity, was also examined. CBD was compared using the same analytical scheme with α-tocopherol. CBD, compared to α-tocopherol, showed a higher scavenging capacity, measured by DPPH• assay, but not better oxidative stability (OSI) of the oily systems considered. In particular, α-tocopherol (0.5%) showed an antioxidant activity only in SO, registered by an increase of more than 30% of the OSI (from 4.15 ± 0.07 to 6.28 ± 0.11 h). By ESR-forced oxidation assay, the concentration of free radicals (μM) in ROO decreased from 83.33 ± 4.56 to 11.23 ± 0.28 and in SO from 19.21 ± 1.39 to 6.90 ± 0.53 by adding 0.5% α-tocopherol. On the contrary, the addition of 0.5% CBD caused a worsening of the oxidative stability of ROO (from 23.58 ± 0.32 to 17.28 ± 0.18 h) and SO (from 4.93 ± 0.04 to 3.98 ± 0.04 h). Furthermore, 0.5% of CBD did not lower dramatically the concentration of free radicals (μM) as for α-tocopherol, which passed from 76.94 ± 9.04 to 72.25 ± 4.13 in ROO and from 17.91 ± 0.95 to 16.84 ± 0.25 in SO
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
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