724 research outputs found

    Synthesis of Statistical Indicators to Evaluate Quality of Life in the Italian Provinces

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    This work remarks the need to carefully evaluate the real importance of each variable used in a multivariate analysis context, with particular regard to cases when an overall performance ranking is the main final purpose. In particular, both a preliminary transformation of variables – aimed at reducing asymmetry and variability of their variation ranges – and the evaluation of their intrinsic explicative power – through redundancy analysis and weighting methods – are proposed. Theoretical and empirical considerations are developed in the frame of quality of life evaluation, carried out at the Italian provinces level on the basis of a yearly survey managed by the Italian economic newspaper "Il Sole24ore". A particular emphasis is given to some normalisation criteria and the case when original variables are grouped "a priori" into logical blocks. A final comparison between the actual ranking method and a series of alternatives is proposed as well.multivariate analysis, principal components analysis, ranking, redundant variable, weighing system.

    Genetic variants of Y chromosome are associated with a protective lipid profile in black men

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    Objective— Gender and ethnicity modulate the phenotypic expression of cardiovascular risk factors. In particular, men are at higher risk of developing cardiovascular diseases compared to women, whereas black populations of African origin display reduced mortality from coronary heart disease (CHD) as compared to both whites and South Asians. Because the male-specific region (MSY) of the human Y chromosome is an obvious candidate for gender-related differences in the development of cardiovascular diseases, we aimed to identify genetic variants of MSY influencing cardiovascular risk profile in different ethnic groups. Methods and Results— We genotyped 4 polymorphisms of MSY (HindIII±, rs768983 of TBL1Y, rs3212292 of USP9Y, and rs9341273 of UTY genes) in 579 men of different ethnic groups (blacks, South Asians, and whites) from UK and in 301 whites in Italy. We found that the TBL1YA USP9YA haplotype, present only in blacks in whom it represents the most frequent allelic combinations (AA: n=125; all other combinations: n=45), was associated with lower levels of triglycerides (P=0.025) and higher levels of HDL-cholesterol (P=0.005) as compared to the other haplotypes. Conclusion— The TBL1YA USP9YA haplotype of the Y chromosome, present only in black people of African origin, attributes a favorable lipoprotein pattern, likely to contribute to their reduced susceptibility to coronary heart disease. The study evaluated the association of genetic variants of the male-specific region of the Y chromosome with cardiovascular risk factors in different ethnic groups. The most frequently observed haplotype in black people was associated with a favorable lipoprotein pattern, thus contributing to the lower rate of cardiovascular diseases in blacks

    IL RUOLO DELL'UNIONE EUROPEA NEL CONTESTO DEL TURISMO INTERNAZIONALE

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    Il lavoro propone una raccolta organica di dati statistici relativi agli spostamenti internazionali di viaggiatori da e verso stati europei e, in particolare, stati aderenti all'Unione Europea. Sulla base della sistematizzazione concettuale delle informazioni attualmente disponibili da varie fonti, si è tentato di quantificare, in chiave comparativa, i livelli di tali spostamenti e le variazioni intercorse negli ultimi anni. In generale, gli stati entrati nell'Unione più recentemente presentano trend di visitatori in entrata superiori a quelli degli stati dell'Unione più anziani.

    Impact of biopolymer matrices on relaxometric properties of contrast agents

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    Properties of water molecules at the interface between contrast agents (CAs) for magnetic resonance imaging and macromolecules could have a valuable impact on the effectiveness of metal chelates. Recent studies, indeed, demonstrated that polymer architectures could influence CAs' relaxivity by modifying the correlation times of the metal chelate. However, an understanding of the physico-chemical properties of polymer/CA systems is necessary to improve the efficiency of clinically used CAs, still exhibiting low relaxivity. In this context, we investigate the impact of hyaluronic acid (HA) hydrogels on the relaxometric properties of Gd-DTPA, a clinically used CA, to understand better the determining role of the water, which is crucial for both the relaxation enhancement and the polymer conformation. To this aim, water self-diffusion coefficients, thermodynamic interactions and relaxometric properties of HA/Gd-DTPA solutions are studied through time-domain NMR relaxometry and isothermal titration calorimetry. We observed that the presence of Gd-DTPA could alter the polymer conformation and the behaviour of water molecules at the HA/Gd-DTPA interface, thus modulating the relaxivity of the system. In conclusion, the tunability of hydrogel structures could be exploited to improve magnetic properties of metal chelates, inspiring the development of new CAs as well as metallopolymer complexes with applications as sensors and memory devices

    On special quadratic birational transformations of a projective space

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    A birational map from a projective space onto a not too much singular projective variety with a single irreducible non-singular base locus scheme (special birational transformation) is a rare enough phenomenon to allow meaningful and concise classification results. We shall concentrate on transformations defined by quadratic equations onto some varieties (especially projective hypersurfaces of small degree), where quite surprisingly the base loci are interesting projective manifolds appearing in other contexts; for example, exceptions for adjunction theory, small degree or small codimensional manifolds, Severi or more generally homogeneous varieties. In particular, we shall classify: quadro-quadric transformations into a quadric hypersurface; quadro-cubic transformations into a del Pezzo variety; transformations whose base locus (scheme) has dimension at most three.Comment: This is my Ph.D. thesis, with the addition of a few other example

    Evaluating North Sea Water Level Monitoring Network Considering Uncertain Information Theory Quantities

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    Information-theory provides, among others, conceptual methods to quantify the amount of information contained in a random variable, as well as methods to quantify the amount of information contained and shared among two or more variables. Although these concepts have been successfully applied in Hydrology and other fields, the valuation of these quantities is sensible to different parameters used to estimate the probabilities that underline the entropy concept. Typical examples are the bin size of histograms used to compute probabilities and the Kendall correlation coefficient used to estimate copula entropy. The selection of these parameters has subsequent effects on other Information Theory quantities such as Joint Entropy and Total Correlation, which are commonly used in optimization procedures for monitoring networks. The present research aims at introducing a method to take into consideration the uncertainty coming from these parameters in the evaluation of the North Sea’s water level network. The main idea is to represent entropy of random variables through their probability distribution, instead of considering entropy as a deterministic value. The method considers solving multiple scenarios of Multi-Objective Optimization in which, for a given set of stations, information content (Joint Entropy) is maximized and redundancy (Total Correlation) is minimized. These scenarios are generated with parameter sampling methods such as the Latin Hypercube. Results include probabilistic analysis of the chosen parameters on the resulting family of Pareto fronts, providing additional criteria on the selection of the final set of monitoring points and the elimination of redundant/non-informative points. Data used was the raw data available from the Dutch Ministry of Infrastructure and Environment. The resulting water level monitoring network will be compared to the one obtained by other methods that will be described in a report currently under preparation, which will be publicly available soon in the Deltares websit

    Data selection to assess bias in rainfall radar estimates. An entropy-based method

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    Miscalibration of radar determines a systematic error (i.e., bias) that is observed in radar estimates of rainfall. Although a rain gauge can provide a pointwise rainfall measurement, weather radar can cover an extended area. To compare the two measurements, it is necessary to individuate the weather radar measurements at the same location as the rain gauge. Bias is measured as the ratio between cumulative rain gauge measurements and the corresponding radar estimates. The rainfall is usually cumulated, taking into account all rainfall events registered in the target area. The contribution of this work is the determination of the optimal number of rainfall events that are necessary to calibrate rainfall radar. The proposed methodology is based on the entropy concept. In particular, the optimal number of events must fulfil two conditions, namely, maximisation of information content and minimisation of redundant information. To verify the methodology, the bias values are estimated with 1) a reduced number of events and 2) all available data. The proposed approach is tested on the Polar 55C weather radar located in the borough area of Rome (IT). The radar is calibrated against rainfall measurements of a couple of rain gauges placed in the Roman city centre. Analysing the information content of all data, it is found that it is possible to reduce the number of rainfall events without losing information in evaluating the bias
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