1,720,999 research outputs found
Sicilia, mordi e fuggi
No full textL'isola è il primo approdo in Europa per tre migranti su quattro, quasi tutti decisi a proseguire verso nord. Il contributo si sofferna sul caso di Catania, dove la prima generazione di nuovi arrivati risale agli anni Settanta. Tutto ricade sul terzo settore. La paura del bianco fra i giovani subsahariani
Fitting insurance and economic data with outliers: a flexible approach based on finite mixtures of contaminated gamma distributions
No full textInsurance and economic data are frequently characterized by positivity, skewness, leptokurtosis, and multi-modality; although many parametric models have been used in the literature, often these peculiarities call for more flexible approaches. Here, we propose a finite mixture of contaminated gamma distributions that provides a better characterization of data. It is placed in between parametric and non-parametric density estimation and strikes a balance between these alternatives, as a large class of densities can be implemented. We adopt a maximum likelihood approach to estimate the model parameters, providing the likelihood and the expected-maximization algorithm implemented to estimate all unknown parameters. We apply our approach to an artificial dataset and to two well-known datasets as the workers compensation data and the healthcare expenditure data taken from the medical expenditure panel survey. The Value-at-Risk is evaluated and comparisons with other benchmark models are provided.</p
Could the Bass model be applied to Italian emigration?
Get PDFObjectives. Our work is a first attempt at verifying whether the diffusionist theory - a framework extensively employed in the demographic literature to interpret the spread of new ideas and practices - can adequately and meaningfully explain migration decisions and related migration data.
Methods. We test whether the Bass model can properly fit the new Italian emigration when working with absolute values. In this sense, we propose interpolation applications for the different Italian macro-areas, separately.
Results. The Bass model detects geographic differences in the underlying dynamics governing the new emigration flows. In Bass terms, the diffusion of the new emigratory behaviour travels at two different speeds in the Northern-Central Italy and in the South. The forces governing the pace of diffusion also reveal a geographic heterogeneity, presenting North-South divergences
Immigrants’ settlement patterns in the city of Naples
No full textABSTRACT. Residential segregation is the outcome of both economic inhomogeneities within the urban space and attraction among individuals sharing the same ethnicity. Here we focus on the settlement patterns originated by different groups of immigrants in the city of Naples. We use the inhomogeneous L-function for measuring segregation due to spatial attraction, while adjusting for the effects of inhomogeneity. Monte Carlo simulations have been used to build confidence envelopes for the null hypothesis of absence of spatial attraction. All nationalities exhibited significant spatial attraction at all considered distances, except for Romania and Poland. However, spatial attraction resulted much stronger for immigrants from Pakistan, China, and Sri Lanka.
RIASSUNTO. La segregazione residenziale è la risultante di disomogeneità economiche all’interno dello spazio urbano e dell’attrazione tra individui della stessa etnia. In questo lavoro, noi considerazione i modelli insediativi originati da diversi gruppi di immigrati stranieri nella città di Napoli ed impieghiamo la funzione L disomogenea per misurare la segregazione causata dall’attrazione spaziale, tenendo sotto controllo le disomogeneità spaziali. Tramite simulazioni Monte Carlo abbiamo costruito degli intervalli di confidenza per l’ipotesi nulla di assenza di attrazione. Tutte le nazionalità analizzate hanno mostrato un’attrazione spaziale significativa a tutte le distanze considerate, ad eccezione di Rumeni e Polacchi. Un’attrazione più forte è stata osservata per gli immigrati provenienti dal Pakistan, Cina e Sri Lanka
Residential Segregation of Foreign Immigrants in Naples
No full textEthnic residential segregation has become a compelling issue in Europe,
following from a debate that links segregation with the failure of integrating
immigrants into host societies. This paper focus on residential segregation among
foreign migrants in the city of Naples. We distinguish among ‘enforced’ and
‘voluntary’ segregation; to this end, we use point pattern analysis to assess the
residual clustering of migrant households after having adjusted for economic
inhomogeneity within the urban area, noticeably in the cost of rents and in the
availability of specific types of jobs. To avoid the risk of confounding the two
sources of segregation, a case–control approach in which cases are migrant
households and controls are a random sample of native households is introduced.
Overall, Eastern European migrants showed no segregation, whereas Chinese
reported the highest voluntary segregation. Sri Lankans, Filipinos and Dominicans
also showed significant levels of voluntary segregation
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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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