1,721,069 research outputs found
Semi-abelian condition for color Hopf algebras
Full text linkRecently, in [22], it was shown that the category of cocommutative Hopf algebras
over an arbitrary field k is semi-abelian. We extend this result to the category
of cocommutative color Hopf algebras, i.e. of cocommutative Hopf monoids in
the symmetric monoidal category of G-graded vector spaces with G an abelian
group, given an arbitrary skew-symmetric bicharacter on G, when G is finitely
generated and the characteristic of k is different from 2 (not needed if G is finite
of odd cardinality). We also prove that this category is action representable and
locally algebraically cartesian closed, then algebraically coherent. In particular,
these results hold for the category of cocommutative super Hopf algebras by taking
G = Z_{2}. Furthermore, we prove that, under the same assumptions on G and k,
the abelian category of abelian objects in the category of cocommutative color
Hopf algebras is given by those cocommutative color Hopf algebras which are also
commutative
“Grandi opere” civili. L’effetto del capitale sociale bridging sulla cultura civile in Italia.
No full textL’obiettivo di questo volume è definire le proprietà delle reti di relazioni e la loro influenza sulla cultura civile. Il riferimento alle grandi opere e alla metafora del ponte è dovuto ai risultati delle analisi teoriche ed empiriche (tramite modelli SEM), dalle quali è emerso che le persone caratterizzate da una conformazione aperta dei propri reticoli sociali, definita bridging, presentano livelli più elevati di cultura civile. Inoltre, attraverso l’analisi secondaria dei dati derivanti da una rilevazione a livello nazionale, è stato possibile fornire un quadro complessivo della cultura civile in Italia, definendo quali aspetti funzionano meglio e le caratteristiche che ne favoriscono la presenza. In questo contesto è stata evidenziata la presenza di atteggiamenti mediamente positivi di cultura civile, che però sporadicamente si concretizzano in comportamenti attivi di impegno civico
Riflessioni sulla valutazione di un modello teorico: comparazione tra tecniche di analisi causale multivariata
No full textLa presente riflessione nasce nell'ambito della tesi di dottorato dalla necessità di verificare l'ipotesi che il capitale sociale agisca come mediatore tra individuo e cultura civile. L'approccio seguito è di tipo relazionale, integrato con l'analisi dei reticoli sociali. La ricerca prevede quindi una componente empirica di tipo deduttivo: si suppone che il capitale sociale rappresenti una variabile interveniente nel rapporto tra i soggetti e la loro cultura civile. Per raggiungere questo obiettivo è stata utilizzata l'integrazione tra le tecniche di Social Network Analysis con la survey classica, attraverso lo studio dei networks personali per favorire la corroborazione di ipotesi attraverso modelli esplicativi multivariati, utilizzando anche le misure strutturali tipiche della network analysis.
I dati empirici derivano da un'indagine nazionale svolta su un campione probabilistico di 1.226 soggetti presso i quali sono stati rilevati il contenuto e la forma delle reti di sostegno e pertanto si intende corroborare l'ipotesi di base attraverso i dati relativi al campione nazionale, quindi con elementi di generalizzabilità.
In questo paper si intende mostrare alcuni problemi metodologici legati al tentativo verificare la compatibilità dell'ipotesi teorica di partenza a livello probabilistico. In particolare, la trattazione prevede il confronto tra tre tecniche di analisi multivariata: la regressione, la path analysis e i modelli di equazioni strutturali (SEM). L'esito della comparazione mostra come i SEM costituiscano la tecnica più generale da cui sono desumibili le altre e favorisce, in particolare, la rilevazione di manifestazioni che riflettono costrutti non osservabili. La scelta della tecnica dipende, comunque, dal quadro teorico, che per i SEM necessita di una maggiore definizione a livello di relazioni tra variabili
Ambiguità nelle risposte al Position Generator
No full textThe Position Generator is a popular measurement instrument for individual level social capital. Empirical studies have tested or discussed measurement properties of the instrument, but not the underlying response process. In 35 semi-structured cognitive interviews across gender, education, and age groups, we asked respondents to reflect on the 1999/2000 Social Survey of the Dutch (SSND) Position Generator. Effects found were unfamiliarity with occupations, interpretation of occupations, unknown occupations of alters, forcing alters into occupations, speculation, forgetting single alters and groups of alters, but not detectable misrepresentation of alters. In only 6 interviews all alters were working in a paid job (as the PG assumes); most remarkable alternatives were retired, unemployed, or deceased alters. An overall impression of the responses is that recalling alters to fit occupations feels counterintuitive to how relationships are memorized. item validity and reliability are therefore likely to be negatively affected, but whether all combined ambiguities affect social capital measures is difficult to predict. Yet, an underestimation of social capital seems likely. Implications and ideas for future development of PGs are discussed
COVID-19 Outbreak through Tweeters’ Words: Monitoring Italian Social Media Communication about COVID-19 with Text Mining and Word Embeddings
Full text linkIn this paper we aim to analyze the Italian social media communication about COVID-19 through a Twitter dataset collected in two months. The text corpus had been studied in terms of sensitivity to the social changes that are affecting people's lives in this crisis. In addition, the results of a sentiment analysis performed by two lexicons were compared and word embedding vectors were created from the available plain texts. Following we tested the informative effectiveness of word embeddings and compared them to a bag-of-words approach in terms of text classification accuracy. First results showed a certain potential of these textual data in the description of the different phases of the outbreak. However, a different strategy is needed for a more reliable sentiment labeling, as the results proposed by the two lexicons were discordant. Finally, although presenting interesting results in terms of semantic similarity, word embeddings did not show a predictive ability higher than the frequency vectors of the terms
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
Social capital and social network sites: an empirical analysis of European high school students
Full text linkThis paper shows the results of part of an empirical study which was developed in the sphere of the PACT EU project (Pathways for Carbon Transitions). The performed analysis concerns the social capital of young Europeans in terms of trust, size of personal networks, volunteering activities and usage of social network sites (SNS). The purpose of the work is, on one hand, exploratory, especially in aspects related to the comparison between relational context of social networks and virtual networks. At the same time, the research aims to confirm on this particular population some of the hypothesis coming from the literature on social capital, and to verify the existence of differences between European countries regarding relational characteristics
Pixel vs. Font. Facebook and Young People’s Self-Presentation
Full text linkThis paper explores various strategies for self-presentation used on Facebook, among a sample of 1330 Italian students aged 14-19 years. Based on two social network site practices, the production of text material and the publication of personal photos, we have constructed a model embracing four types of categories and behaviors. We examined the categories according to structural variables, variables regarding self-narration, and two psychological scales. The results show the validity of the four categories in distinguishing different styles of Facebook use and allowing us to define those styles in greater depth. In particular, the publication of photos by those who do not contribute written text seems to indicate the need to maintain one’s real-life social network; the production of text alone seems to reflect the need to deepen one’s most passionate interests; while the combination of the two communicative modes tends to reveal a greater capacity in planning for the future
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
Making Our Way Through the Crisis. Life Course, Turning Points, and Personal Reflexivity
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