1,721,224 research outputs found
Dysfunctional Cognitions in Online Gaming and Internet Gaming Disorder: a Narrative Review and New Classification
No full textMetacognitions and emotional regulation as predictors of problematic Internet use in adolescents
Full text linkObjective: Problematic Internet Use (PIU), broadly conceptualized as an inability to control one’s use of the Internet
leading to negative consequences in daily life, is fast becoming a matter of significant concern in our society, particularly
in adolescents. In the present study we aimed to assess a model in which metacognitions and emotion regulation
independently predicted PIU.
Method: A total of 380 adolescent students from a secondary school in Italy voluntarily participated in the study.
Students completed a set of online self-report scales assessing PIU, metacognitions, and emotion regulation.
Results: Metacognitions, with the exception of cognitive self-consciousness, were positively correlated with PIU.
Moreover, emotion regulation negatively correlated with PIU. The model tested indicated that both metacognitions
and emotion regulation had direct effects (positive and negative respectively) on PIU and that the relationship between
metacognitions and emotion regulation was not significant.
Conclusions: Both metacognitions and emotion regulation appear to be relevant to PIU among adolescents. We
discuss the implications of these findings
Impact of alien species on dune systems: a multifaceted approach
No full textWe applied a multifaceted approach, in terms of taxonomic, phylogenetic and functional diversity, to study at fine scale how three plant communities occurring in a Mediterranean dune have been affected by the encroachment of alien species. We sampled 81 sites in a Site of Community Importance in Central Italy. Past and present land use/cover data have been derived using GIS and remote sensing tools. Information on plants phylogenesis and functional traits has been gathered from several databases. Ecological variables have been collected. GLMs in conjunction with an Information Based approach were used to model species composition, richness and phylogenetic diversity. Multivariate analysis has been used to study functional diversity. The results outlined how total species richness is related to recent land transformations and to a set of environmental factors. The analyses of functional and phylogenetic diversity support the idea that alien species significantly affect the functional and phylogenetic characteristics of the native plant communities. Habitat filtering seems to be predominant in not-invaded plots, whereas limiting similarity/niche differentiation is predominant in driving community assembly of invaded communities. The attained scenario depicts the spread of a reduced group of alien species phylogenetically and functionally well-differentiated, able to reduce the abundance of native species, not to exclude them though. Ultimately, the multifaceted approach assisted in understanding the community assembly of dune vegetation, and to discern the relative impact of alien species on native plant communities. Such approach represents a crucial step to achieve an efficient management of dune habitats, as useful tool to monitor and to effectively protect their biodiversity and functionin
Measuring Rao’s Q diversity index from remote sensing: an open source solution
No full textMeasuring biodiversity is a key issue in ecology to guarantee effective indicators of ecosystem health at different spatial and time scales. However, estimating biodiversity from field observations might present difficulties related to costs and time needed. Moreover, a continuous data update for biodiversity monitoring purposes might be prohibitive. From this point of view, remote sensing represents a powerful tool since it allows to cover wide areas in a relatively low amount of time. One of the most common indicators of biodiversity is Shannon's entropy H′, which is strictly related to environmental heterogeneity, and thus to species diversity. However, Shannon's entropy might show drawbacks once applied to remote sensing data, since it considers relative abundances but it does not explicitly account for distances among pixels’ numerical values. In this paper we propose the use of Rao's Q applied to remotely sensed data, providing a straightforward R-package function to calculate it in 2D systems. We will introduce the theoretical rationale behind Rao's index and then provide applied examples based on the proposed R functio
Beyond CAPM: estimating the cost of equity considering idiosyncratic risks
No full textThe present study proposes a new evaluation approach aimed at estimating the cost of equity through standardized models which consider an innovative set of firm-specific information on the main unsystematic risks which are typical of any business. Our objective is extending the Capital Asset Pricing Model (CAPM) by defining a standard formula for quantifying the premium for certain idiosyncratic risks as a function of a new set of firm-specific quantitative information. We define two econometric models, for listed and non-listed firms respectively, which consider five idiosyncratic risk factors: firm size, value factor, operating risks, financial structure and stock market price volatility. The models were tested on a sample of European non-financial companies. The empirical results show that while the CAPM systematically underestimates the cost of equity, the proposed models correctly estimate its expected value; furthermore, they show a slight improvement also in terms of estimates’ volatility. Due to their efficacy and ease of use, the proposed models represent a valid practical tool for investors, analysts and professional evaluators. This work contributes to the existing literature by proposing a typologically innovative extension of the CAPM set of explanatory variables, defining and testing new models for the estimation of the unsystematic risks’ spread of the cost of equity based on an original set of firm-specific accounting and market information
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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