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Search Results: 1 - 10 of 1278 matches for " Stefania Porcu "
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Allergies in Children: What’s New?—A Cross-Sectional Descriptive Study  [PDF]
Daniela Simoncini, Anna Peirolo, Alberto Macchi, Stefania Porcu, Daniela Graziani, Luigi Nespoli
Open Journal of Pediatrics (OJPed) , 2015, DOI: 10.4236/ojped.2015.54045
Abstract: Background: The prevalence of respiratory allergies is increasing worldwide, with important consequences especially for little children. Objective: The aim of this study was to assess the prevalence of respiratory allergies, such as rhinitis and asthma, and to point out the risk factors and their relationship with allergic diseases in a specific area of Northern Italy. Methods: 110 children, male and female, from our outpatient service for allergic children, between 3 and 17 years old, were examined. After a skin prick test and a nasal cytology, the written questionnaire of the International Study of Asthma and Allergies in Childhood was filled by parents together with their children. Results: 110 children were examined. 74% of children had rhinitis and 71% asthma. 88 patients were allergic, grass pollen and house dust mite was the most frequent allergens. A family history of atopy, family background, geographic area, active and passive smoking and home pets were associated to allergies. Older children (6 - 15 years old) had more often rhinitis associated with asthma and conjunctivitis as compared to younger. 21 Children were also affected by non allergic rhinitis. Conclusions: Respiratory allergies are widespread and associated to a low quality of life among little children. Sensitization to Ragweed is increasing with important consequences. Rhinitis precedes the onset of asthmatic symptoms. Moreover non allergic rhinitis is increasing and frequently underdiagnosed.
Un uomo, un matematico: Umberto Gasapina
Livio Porcu
Le Matematiche , 1996,
Abstract: A remembrance of Umberto Gasapina.
Does Education Affect Individual Well-Being? Some Italian Empirical Evidences  [PDF]
Francesca Giambona, Mariano Porcu, Isabella Sulis
Open Journal of Statistics (OJS) , 2014, DOI: 10.4236/ojs.2014.45032

Using data from the last European Survey on Income and Living Conditions (EU-SILC), this paper focuses on the measurement of well-being and on its association with education. EU-SILC survey gives information on several aspects of people’s daily life (i.e. housing, labour, health, education, finance, material deprivation and possession of durables) allowing a multi-dimensional approach to the study of well-being, poverty and social exclusion. For our aims we have considered only survey data collected in Italy. Due to the multidimensionality of well-being concept, we have selected some variables related principally to four main dimensions of well-being, which are financial endowment, housing conditions and goods possessions, health status, and environment. A first explanatory analysis via multivariate regression model has highlighted the effect of education on the factors considered. Finally, a latent class regression analysis has been used to cluster individuals into mutually exclusive latent classes which identify different intensities of well-being (the latent trait) taking into account the effect of education in the membership probability of each latent class.

Modified Maximum Likelihood Estimation in Autoregressive Processes with Generalized Exponential Innovations  [PDF]
Bernardo Lagos-álvarez, Guillermo Ferreira, Emilio Porcu
Open Journal of Statistics (OJS) , 2014, DOI: 10.4236/ojs.2014.48058
Abstract: We consider a time series following a simple linear regression with first-order autoregressive errors belonging to the class of heavy-tailed distributions. The proposed model provides a useful generalization of the symmetrical linear regression models with independent error, since the error distribution covers both correlated innovations following a Generalized Exponential distribution. Furthermore, we derive the modified maximum likelihood (MML) estimators as an efficient alternative for estimating model parameters. Finally, we investigate the asymptotic properties of the proposed estimators. Our findings are also illustrated through a simulation study.
Toward an estimation of the relationship between cyclonic structures and damages at the ground in Europe
F. Porcu,A. Carrassi
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2009,
Abstract: Cyclonic systems dominate European and Mediterranean meteorology throughout the year and often induce severe weather in terms of heavy and/or long-lasting precipitation with related phenomena such as strong winds and lightning. Surface cyclonic structures are often related to well defined precipitation patterns with different scales, duration and intensity. Cyclones confined in the upper troposphere, usually referred to as cut off low, may induce instability at lower levels and the development of convective precipitation. In this work the occurrence of cyclonic events (discriminated between surface ones and cut-off lows) is analyzed and matched with an economic losses database to highlight a relation between the atmospheric structures and the impact on the social environment in terms of casualties and material damages. The study focus on the continental Europe and, based on the ERA-40 reanalysis, two databases of surface cyclones and cut-off lows have been constructed by means of automatic pattern recognition algorithms. The impact on the local communities is estimated from an insurance company record, which provides the location, date and type of the events, as well as related losses in terms of damages and casualties. Results show the relatively high impact of cyclonic structures on human life in Europe: most of the weather induced damages occur close to a cyclonic center, especially during warm months. Damages and human losses are more frequent from late summer to January, and precipitation is the most relevant meteorological damaging feature throughout the year.
Adriana Mihaela PORCU?AN
Geographia Napocensis , 2010,
Abstract: Publicitatea n turism - Rela ia dintre Romania i Ucraina. Euroregiunile sunt un fapt n lumea modern , cat i n turismul care se poate dezvolta ntre rile care mpart aceea i grani . n lucrarea de fa noi vom face referire la Romania i Ucraina. Ele mpart aceea i grani , o parte din atrac iile naturale, culturale, etnice, religioase, dar nu au accea i importan n turismul interna ional. n cazul promov rii n turism, internetul este o cale foarte important de a prezenta o atrac ie, o surs foarte rapid , ieftin i disponibil oricand pentru turi ti i pentru a g si informa iile pe care le caut . Dac facem o compara ie ntre promovarea turismului n Romania i Ucraina, g sim mari diferen e pentru c Romania este o ar care se concentreaz pe turismul extern, iar Ucraina se concentreaz pe cel intern, fiind a aptea ar n lume ca receptoare de turi ti. Acest lucru este ar tat i de limba care este folosit de site-urile fiec rei ri: aproape numai roman n Romania, englez i ucrainean n Ucraina.
From Schoenberg coefficients to Schoenberg functions
Christian Berg,Emilio Porcu
Mathematics , 2015,
Abstract: In his seminal paper, Schoenberg (1942) characterized the class P(S^d) of continuous functions f:[-1,1] \to \R such that f(\cos \theta) is positive definite over the product space S^d \times S^d, with S^d being the unit sphere of \R^{d+1} and \theta being the great circle distance. In this paper, we consider the product space S^d \times G, for G a locally compact group, and define the class P(S^d, G) of continuous functions f:[-1,1]\times G \to \C such that f(\cos \theta, u^{-1}\cdot v) is positive definite on S^d \times S^d \times G \times G. This offers a natural extension of Schoenberg's Theorem. Schoenberg's second theorem corresponding to the Hilbert sphere S^\infty is also extended to this context. The case G=\R is of special importance for probability theory and stochastic processes, because it characterizes completely the class of space-time covariance functions where the space is the sphere, being an approximation of Planet Earth.
From Schoenberg to Pick-Nevanlinna: Toward a complete picture of the variogram class
Emilio Porcu,René L. Schilling
Mathematics , 2008, DOI: 10.3150/10-BEJ277
Abstract: We show that a large subclass of variograms is closed under products and that some desirable stability properties, such as the product of special compositions, can be obtained within the proposed setting. We introduce new classes of kernels of Schoenberg-L\'{e}vy type and demonstrate some important properties of rotationally invariant variograms.
Space-time covariance functions with compact support
Viktor P. Zastavnyi,Emilio Porcu
Mathematics , 2009,
Abstract: We characterize completely the Gneiting class of space-time covariance functions and give more relaxed conditions on the involved functions. We then show necessary conditions for the construction of compactly supported functions of the Gneiting type. These conditions are very general since they do not depend on the Euclidean norm. Finally, we discuss a general class of positive definite functions, used for multivariate Gaussian random fields. For this class, we show necessary criteria for its generator to be compactly supported.
A. Cherubini,Alberto Conte,Livio Porcu
Le Matematiche , 1996,
Abstract: Presentazione.
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