Riviste Online SApienza - R.O.SA - 2 (Sapienza University of Rome)
Not a member yet
1407 research outputs found
Sort by
A critical review of the odonate fauna of Trentino: annotated check-list and new relevant data for Italy (Insecta: Odonata)
Get PDFBy the first half of the Twentieth Century, the Odonate fauna of Trentino (Oriental Alps, Italy) was quite well known; subsequently, few surveys on dragonflies were carried out, resulting in a limited update of the knowledge on this taxon. The aim of this study is to provide a critical and annotated check-list of the Odonata of this province for the period from 1851 to 2018. This synthesis is based on a total of 3814 records obtained from the literature (955 records), revision of collections (1048 records), and unpublished recent data (1811 records). An updated and comprehensive Odonatological bibliography of the region is also provided. Overall, sixty-one species were confirmed to occur (or have occurred) in Trentino. These represent the 64% of the species recorded in Italy and the 43% of the species recorded in Europe. Presence of five additional species (Ceriagrion tenellum, Coenagrion lunulatum, C. ornatum, Ophiogomphus cecilia, and Epitheca bimaculata) should be considered doubtful for Trentino. Further two species (Platycnemis latipes and Onychogomphus uncatus) have to be excluded from the fauna of the study area. Fifty-four species were recorded also after 2000, whereas seven species were not confirmed after this year (Lestes dryas, L. virens, L. barbarus, Sympecma paedisca, Coenagrion scitulum, Brachytron pratense, and Sympetrum flaveolum). Several new records resulting from this study (referred to: Erythromma najas, Aeshna subarctica, Aeshna caerulea, Aeshna grandis, Leucorrhinia pectoralis) have a conservation or biogeographical relevance which transcends the borders of the study area, being noteworthy from an Italian or Alpine perspective and are thus commented in detail. Taxonomic notes on subspecies are also given when relevant
A new genus and species of Mesostylini Reitter, 1913 (Coleoptera: Curculionidae)
Get PDFIs described the new genus Viridistylus n. gen. and its type species Viridistylus robustus n. sp. from Tajikistan belonging to the entimine tribe Mesostylini. A key to the genera of Mesostylini thus far known, and illustration of the new species are included
Flood hazard mapping in convex floodplain: multiple probability models fusion, bank threshold and levees effect spatialization
Get PDFThis paper presents a first attempt to model flood hazard in convex upward floodplains through the combination of multiple probability models fusion and topographic-based flood inundation models. Our procedure is optimized for convex floodplains through the adoption of a multiplicative probability threshold that simulates the effect of natural banks bounding the river course and is able to account for the presence of artificial levees. We have applied this procedure to a segment of the lower course of the Volturno river in the Caserta Province. This area has been historically affected by flood events and since 1927 has been monitored with several hydrometric stations. We have used data from two of these stations and a LiDAR derived high-resolution topography to develop two flood hazard scenarios. The first is derived using a Generalized Extreme Value distribution, while the second is derived using a Gamma distribution function of available data. As boundary condition, we have considered a reference scenario corresponding to an estimated 500-year flood. The hazard maps provide an overview of the flood hazard in the lower sector of the Volturno river
Probabilistic approaches for assessing rainfall thresholds triggering shallow landslides. The study case of peri-Vesuvian area (Southern Italy)
No full textAsh-fall pyroclastic soil deposits covering steep carbonate slopes in the peri-Vesuvian area (southern Italy) are periodically involved in shallow landslides (about 700 events were recorded during the last three centuries, as reported by CASCINI et alii, 2008), triggered by intense and/or prolonged rainfall events, which evolve as catastrophic debris flows. In the last decades, many studies have been focused on estimating reliable relationships among the triggering of shallow landslides and the amount and duration of rainfall events, as well as the role played by antecedent soil hydrological conditions. Results of these studies have been expected to give information on temporal hazard to landslide onset to be used for setting a reliable early warning system. In this paper we present probabilistic approaches to assess rainfall thresholds triggering shallow landslides by classical empirical methods and to manage the uncertainties related to biases of data. At this scope, rainfall events related to the occurrence of debris flows along slopes of the Sarno and Lattari Mountains, known from chronicles of the last century, were analyzed by means of the empirical models of Intensity-Duration (I-D) (CAINE, 1980) and rainfall recorded in the day of the landslide occurrence (P) vs the antecedent cumulated rainfall (Pa) (CROZIER & EYLES, 1980). In order to limit and to assess uncertainties related to biases of rainfall data, a comparison with the regional probability model of high intensity rainfall, carried out in the framework of the VAPI Project (ROSSI & VILLANI, 1994) has been carried out. Moreover, rainfall data were processed by a bivariate logistic regression model resulting in the assessment of probability to landslide triggering, given an assumed rainfall event. The I-D empirical rainfall thresholds obtained by Caine model (1980) were compared to rainfall thresholds estimated by deterministic approaches (DE VITA et alii, 2013; NAPOLITANO et alii, 2016) showing a good match
Option pricing con volatilità stocastica: analisi ed implementazione del modello di Heston
No full textThe present work aims at evaluating options using the Heston model. This model is presented both from a theoretical and a practical point of view. Initially, we review the salient mathematical steps that lead to its formulation. In particular, the hedging portfolio of the underlying asset price and variance is constructed in order to derive the exercise probability of the option. Afterward, some important aspects related to the implementation of the model are analyzed and the main numerical approaches are discussed: the integration methods and the approaches based on the Fast Fourier Transform (FFT) and the Fractional Fast Fourier Transform (FRFT). We then illustrate the minimization methods of the objective function useful to perform the calibration of the model and, finally, we show the results of an empirical analysis carried out on real data
Welfare state and occupational welfare
No full textThe article draws upon the main results of the Report on Welfare State 2019 edited by the Author. The first part analyses occupational welfare which involves the following aspects: the historical context of the most comprehensive state-market relations in which it developed; the reasons and the economic and social effects of the spread of occupational welfare; the areas of intervention and the dimensions it has assumed in various countries and in Italy; the connections with the welfare state; the links with employer-trade union relationships, productivity trends, decentralized wage bargaining and wage trends; and the effects on inequalities in access to social goods and services. The following two sections examine the social and economic policies implemented in Europe and Italy, and the quantitative and qualitative dynamics of expenditure. In particular, we explore: trends and policies regarding: the labor market; demographic and migration trends; education and healthcare; social safety networks; inequalities; the policies aimed at reducing poverty; and the basic guaranteed citizens’ income (reddito di cittadinanza) a measure recently introduced in Italy. Finally, the analysis focuses on the measures adopted by the Italian Government in relation to the pension system, as well as the forecasts, problems and recommendations concerning public and private systems
Physical and mechanical characteristics of the gravina calcarenite (southern Italy)
Get PDFOne of the most important problems in designing engineering works is the knowledge of the strength parameters of the rock masses. Beside the soil-structure interaction, a satisfactory performance of structures requires that rock mass properties such as deformation modulus, intact rock and global rock mass strengths and shear strength parameters are reliably defined. The studied Calcarenite of Gravina, is a calcarenitic rock outcropping in the area of the town of Matera (Southern Italy). It is a natural soft rock, mainly used since prehistoric times as building and dimension stone, considered durable although air pollution and water weathering markedly reduce the mechanical properties both at short and long term. Consequently, locally existing cliffs may be affected by erosive phenomena and, even, by unexpected collapses resulting from complex hydro-chemo-mechanical processes. This paper presents the evaluation of the Calcarenite of Gravina physical and mechanical properties, using laboratory tests on intact rock samples collected in seven different locations. From a macroscopic point of view, calcarenites are highly porous materials showing the presence of three main components: calcareous grains, micrite matrix and sparite cement. Dry and saturated calcarenite samples have been tested according to the ISRM suggested methods at room temperature (~20°). As the studied Calcarenite cannot be considered homogenous rocks, being characterized by largely scattered pore sizes, further research on the effect of porosity on mechanical properties, mainly strength and deformability is needed and still ongoing
Arsenic (III) removal from drinking water using rust waste sand filter
Get PDFThe present study has contributed to the present state of knowledge on the effects of Rust Waste Sand (RWS) on removing arsenic from water. The main contributions of the research are evaluation and investigation the performance of Rust Waste Sand (RWS) on removing arsenic (III) from water, and enhancement of new research area and idea on removing arsenic from water using Rust waste. This paper describes experiments in which Rust Waste Sand (RWS) filter was used to study the removal of arsenic. This filter media was prepared with rust passing through #30 no ASTM sieve and local sand of FM 2.605 with the ratio of 2:1 by weight, and column test was performed to assess the effectiveness and suitability. Ten cycles of column tests were conducted to evaluate the performance of RWS filter media. The arsenic removal by RWS filter media with was significant. Performance of RWS filter in removing As (III) for pH of 6.5, 7.0 and 7.5 water with respect to contract time showed a better result for pH 6.5 and followed by pH 7.0 and pH 7.5. In removing 50% As (III) from water of pH 6.5, 7.0 and 7.5 the contact time were 225, 290 and 350 s respectively whereas iron-oxide coated sand (IOCS) required 1,380 s for the water of pH 7.5-7.8. RWS filter is more effective in removing As (III) from water abruptly than iron-oxide coated sand and others iron based adsorptions materials. Also, it had been investigated that at certain cycle of filtration total iron leaching from the filter in the water were noticed and this concentration was very many low than standard guidelines. The results of column studies showed that RWS filter media could be effectively used as both very low cost and user friendly technology to achieve less than drinking water standard level of As concentration
