1,721,448 research outputs found
Frammenti di un nuovo paesaggio urbano. Il cinema per cercare l'anima delle città e per sostenere nuove politiche urbane
No full textSi tratta di un cortometraggio di 12 minuti girato a Serravalle Scrivia AL, Bergamo, Camerano AN. Soggetto e testi di Sergi G., montaggio di Catalani R. e Ferretti R
A fully semi-Lagrangian technique for viscous and dispersive conservation laws
No full textWe consider a scheme of Semi-Lagrangian type for the approximation of conservation laws with convex or concave flux. Following a previously proposed approach, the scheme treats in explicit form the diffusive/dispersive terms, although it still requires an implicit phase to determine the correct characteristic. We prove consistency and one-sided Lipschitz stability in the viscous case, and show that, despite being nonconservative, the scheme has good performances and negligible conservation error with large Courant numbers as far as the diffusion scales are resolved. Then, the approach is generalized to conservation laws with dispersive terms (in particular, the Korteweg–de Vries equation). We also validate the scheme with a set of numerical examples
The weight of words: textual data versus sentiment analysis in stock returns prediction
Full text linkThe focus of this paper is to understand whether the words contained in a text corpus improves the explained variance of stock returns better than the use of the polarity of the same texts, obtained through a sentiment analysis using a generic ontological dictionary. The empirical analysis is based on the content of a weekly column in the most important Italian financial newspaper, which published past information and analysts’ recommendations on listed companies. The use of textual data clearly increases the explained variance of stock returns but, through comparisons between data mining techniques, we observed minor differences in terms of MSE, by adding a selection of specific terms as features. In this context, the text mining approach proved to be very useful to improve the explanatory power of forecasting models, while it emerged the limited explanatory power of an automatic sentiment analysis based on a generic lexicon
Does the attention-grabbing mechanism work on Sundays? Influence of social and religious factors on investors' attention
No full textPurpose: This paper focuses on the influence of social, cultural and religious factors on investors' attention. In particular, the authors examined if the attention-grabbing mechanism works on Sundays, that is, if the Italians' Sunday activities and habits lead to a lower attention to second-hand financial news, compared to Saturdays. Design/methodology/approach: The authors analyzed the market reaction to equivalent stale events published on the Saturday and Sunday editions of an Italian financial newspaper and conducted a standard event study on abnormal returns and abnormal volumes for Saturday and Sunday columns and a multivariate analysis on abnormal returns for columns reporting positive recommendations. As a robustness check, the authors performed a sentiment analysis of the columns and included this variable in the regression analysis, but sentiment proved to be not significant in the final model. Findings: The study’s results confirmed that the attention-grabbing mechanism directed buying decisions, while had no influence on selling decisions. Furthermore, event study and multivariate analysis showed a significant lower market reaction to Sunday columns, supporting the study hypothesis of a Sunday investors' inattention which can be traced to cultural and/or religious factors since Sunday in Italy is a day devoted to family, entertainment and religious rituals. Practical implications: The lower investors' attention on Sundays and the related influence of social, cultural and religious factors have implications for the timing of both corporate communications and financial advertising. Originality/value: The authors’ paper provides an original contribution, on the empirical ground, to the attention-grabbing theory and to the growing theoretical literature in microeconomics that models attention
Efficient implementation of characteristic-based schemes on unstructured triangular grids
Full text linkLa regolamentazione dello short selling: effetti sul mercato azionario italiano (Short selling ban: effects on the Italian stock market)
Full text linkOn September 2008, Consob banned the short-selling of financial stocks in the Italian equity market. We analyse the effect of these bans on liquidity, returns, volatility and market efficiency comparing a sample of 23 financial stocks with a control group. The analysis shows a reduction in liquidity for the banned stocks and no significant differences in returns, volatility and market efficiency between the two groups, testifying the inability of restrictions to achieve the purpose for which they were introduced
Efficient implementation of characteristic-based schemes on unstructured triangular grids
Full text linkUsing characteristics to treat advection terms in time-dependent PDEs leads to a class of schemes, e.g., semi-Lagrangian and Lagrange–Galerkin schemes, which preserve stability under large Courant numbers, and may therefore be appealing in many practical situations. Unfortunately, the need of locating the feet of characteristics may cause a serious drop of efficiency in the case of unstructured space grids, and thus prevent the use of large time-step schemes on complex geometries. In this paper, we perform an in-depth analysis of the main recipes available for characteristic location, and propose a technique to improve the efficiency of this phase, using additional information related to the advecting vector field. This results in a clear improvement of execution times in the unstructured case, thus extending the range of applicability of large time-step schemes
Is public information really public? The role of newspapers.
Full text linkOur paper offers evidence that printed media can affect stock prices by covering public news (nonevents) even without resorting to spin or emphasis. However, the price reaction is limited to small caps, suggesting that small investors still obtain public information mainly through newspapers. The absence of spin or emphasis is the core element that differentiates our study from existing evidence, making it unique, to the best of our knowledge, in the financial literature on the media and asset pricing
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
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