2,368 research outputs found

    Harmonic theta series and the kodaira dimension of a6

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    We construct a basis of the space S14(Sp12(â„€)) of Siegel cusp forms of degree 6 and weight 14 consisting of harmonic theta series. One of these functions has vanishing order 2 at the boundary which implies that the Kodaira dimension of A6 is nonnegative

    Retrieving cosmological information from small-scale CMB foregrounds. I. The thermal Sunyaev Zel'dovich effect

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    We propose a new analysis of small-scale cosmic microwave background (CMB) data by introducing the cosmological dependency of the foreground signals, focussing first on the thermal Sunyaev-Zel’dovich (tSZ) power spectrum, derived from the halo model. We analyse the latest observations by the South Pole Telescope (SPT) of the high-ℓ power (cross) spectra at 95, 150, and 220 GHz, as the sum of CMB and tSZ signals, both depending on cosmological parameters and remaining contaminants. In order to perform faster analyses, we propose a new tSZ modelling based on machine learning algorithms (namely Random Forest). We show that the additional information contained in the tSZ power spectrum tightens constraints on cosmological and tSZ scaling relation parameters. We combined for the first time the Planck tSZ data with SPT high-ℓ to derive new constraints. Finally, we show how the amplitude of the remaining kinetic SZ power spectrum varies depending on the assumptions made on both tSZ and cosmological parameters. These results show the importance of a thorough modelling of foregrounds in the cosmological analysis of small-scale CMB data. Reliable constraints on cosmological parameters can only be achieved once other significant foregrounds, such as the kinetic SZ and the cosmic infrared background (CIB), are also properly accounted fo

    Italian adaptation and psychometric properties of the prejudice against immigrants scale (PAIS): assessment of validity, reliability, and measure invariance

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    The aim of the current study was to adapt and validate the Prejudice Against Immigrants Scale (PAIS) in the Italian context, based on the Prejudice Against Asylum Seekers Scale by Anderson (2018). The validity, reliability, and measurement invariance across gender, age, and educational levels of the scale were assessed through three sources, which involved 306 Italian individuals (Nmen = 151, 49.3%) between 18 and 60 years old. Both exploratory and confirmatory factor analyses (CFA) confirmed the two-factor solution of the original instrument by excluding two items, which were present in the previous validation study. The first factor is classical prejudice against immigrants, which maps onto theoretical derivations of classical and old-fashioned prejudices, whereas the second factor is conditional prejudice against immigrants, which maps onto theoretical derivations of subtle and modern prejudices. Findings of the multigroup CFAs demonstrated full configural and metric invariance and partial scalar invariance of the scale across gender, age, and educational level. The analyses confirmed that PAIS has high levels of reliability and criterion and construct validity, showing findings that are comparable to those of Anderson (2018). These results suggest that PAIS presents very good psychometric properties and could be considered a valid and reliable instrument to measure prejudice against immigrants, by enabling Italian researchers to detect both covert and more subtle forms of prejudice against immigrants. Limitations and further directions are discussed

    An empirical flood fatality model for Italy using random forest algorithm

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    Due to an increasing occurrence of natural hazards, such as floods, a significant number of lives are lost each year worldwide. The risk of experiencing catastrophic losses from flooding is exacerbated due to the changing climate, and the increasing anthropogenic activities. Consequently, predicting the conditions leading to fatalities is crucial in the assessment of flood risk. However, the existing modeling capabilities in this field, are limited, emphasizing the critical need for the development of such tools. Here, we show that the occurrence of flood fatalities can be estimated using a random forest (RF) algorithm applied to nine explanatory variables characterizing each fatality. Furthermore, by converting the RF model outcomes into a user-friendly tool, it is possible to predict the probability of the occurrence of flood-related fatalities, based on variables describing hazard intensity and the environmental and sociodemographic conditions that contribute to such events. Our results represent an initial attempt towards a predictive model of flood fatalities in the Italian context. They reveal the key factors that together influence flood fatalities, enabling the prediction of such occurrences. These findings can serve as a foundational framework for quantitatively assessing the risk to the population from such events and as a valuable resource for identifying strategies to mitigate flood risk

    Challenges toward Sustainability? Experiences and Approaches to Literary Tourism from Iran

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    Interdisciplinary narrative studies are of great importance in several disciplines, especially in the humanities and social sciences. Cultural tourism and its sub-disciplines, including the complex issue of ‘literary tourism’, is an interdisciplinary field of investigation, positioned in between geography and urban–rural studies. In Iran, this form of tourism has been neglected so far—with no distinction between urban and rural areas—despite a particularly rich literary heritage. The present study recognizes the challenge of literary tourism in Iran, delineating some possible actions to develop it as a future engine of economic growth, especially in rural districts. As a contribution to a refined comprehension of literary tourism development paths, a content analysis was run collecting views and textual data on literary tourism in Iran. The empirical results of this study indicate that the mentioned challenges can be classified into several main dimensions and a broader set of sub-themes. The possible actions responding to such challenges can be classified into more dimensions and a vast number of sub-themes. Actions reducing territorial disparities and fueling entrepreneurship in local communities are appropriate to stimulate the emergence (and, possibly, consolidation) of literary tourism districts in Iran, giving an original contribution to sustainable development especially—but not exclusively—in rural settlements

    Motivation-based Market Segmentation in Rural Tourism: the Case of Sámán, Iran

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    Market segmentation is a pivotal and under-investigated issue when evaluating decision-making processes and motivational factors shaping rural tourism. The present study has examined market segmentsof rural tourists in Iran based on their sociodemographic attributes, travel characteristics and preferred leisure activities, profiling rural tourists on the base of their motivational background. The survey results indicated that rural tourism in the study area is a heterogeneous market, whose development depends on general trends in Middle East tourism market. A comprehensive knowledge of rural tourism actors may help formulating appropriate marketing strategies for internal areas destined to tourism growth

    Robust small area prediction for counts

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    A new semiparametric approach to model-based small area prediction for counts is proposed and used for estimating the average number of visits to physicians for Health Districts in Central Italy. The proposed small area predictor can be viewed as an outlier robust alternative to the more commonly used empirical plug-in predictor that is based on a Poisson generalized linear mixed model with Gaussian random effects. Results from the real data application and from a simulation experiment confirm that the proposed small area predictor has good robustness properties and in some cases can be more efficient than alternative small area approaches

    Factors underlying life quality in urban contexts: Evidence from an industrial city (arak, iran)

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    Cities play a vital role in local development providing a high education level, specialized jobs and advanced services. When assessing living conditions and wellbeing in cities, economic indicators alone are generally unable to evaluate the inherent complexity of the 'quality of life' issue in urban environments. With rapid urbanization, shortage of infrastructures and services emerged in metropolitan regions of developing countries, leading to disadvantaged settlements, urban poverty, lower citizens' satisfaction, and an overall decline in life quality. Based on these premises, the present study illustrates a subjective investigation of life quality in an emerging economy such as Iran, focusing on Arak, the fourth largest industrial pole of the country. Based on a literature review on quality of life in industrial cities of emerging economies, subjective indicators of citizens' satisfaction on living quality in Arak were identified and quantified using empirical results from a field survey. Results of our study show that the overall satisfaction for living quality in Arak is rather low, reaching the lowest rank in the issues of environmental sanitation and public transportation. Lack of investments in urban infrastructure justifies the low citizens' perception of life quality in Arak city. The paper concludes outlining the urgent need of homogeneous and comparable macro-and micro-data on multiple aspects of quality of life at both city-level and metropolitan-level in emerging economies

    Optical and X-ray Spectroscopy of 1E 0449.4-1823: Demise of the original type 2 QSO

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    New optical spectra of the original narrow-line quasar 1E 0449.4-1823 show that it now has broad emission lines of considerable strength, eliminating it as a "type 2 QSO" candidate. We suggest that the behavior of 1E 0449.4-1823 is the same as that of some Seyfert 1.8 and 1.9 galaxies, in which Goodrich attributed long-term variations of their broad Balmer lines to dynamical motions of obscuring material located in or around the broad-line region. The optical continuum and broad emission-line regions of 1E 0449.4-1823 may still be partly covered in our line of sight, which would explain its large forbidden-line equivalent widths and flat alpha_ox relative to other low-redshift QSOs. Also present are apparent absorption features in the broad Balmer lines and in Mg II, which may be related to the past obscuration and current emergence of the broad-line region. However, it is difficult to distinguish absorption from broad emission-line peaks that are displaced in velocity; we consider the latter a plausible competing interpretation of these peculiar line profiles. An ASCA X-ray spectrum of 1E 0449.4-1823 can be fitted with a power-law of Gamma = 1.63, intrinsic N_H < 9 x 10^20 cm-2, and no Fe Kalpha line emission. Its 2-10 keV luminosity is 6.7 x 10^44 ergs/s. With regard to the still hypothetical type 2 QSOs, we argue that there is little evidence for the existence of any among X-ray selected samples.Comment: to appear in ApJ July 1, 1998 (vol. 501). 23 pages including figures. Uses LaTeX macro aasms4.st
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