Riviste Online SApienza - R.O.SA - 2 (Sapienza University of Rome)
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Statistical inference with skew t distributions: the mvst r package
No full textWe consider a Bayesian analysis of a general regression model with skew-elliptically distributed errors. In particular, we describe the choice of the prior distributions and we propose a Monte Carlo algorithm which allows: i) fast and accurate estimates of the posterior distribution of the parameters ii) to perform model choice among nested families of skew-elliptical classes of densities. All the methods described in the paper are implemented in the new version of the R package mvst. The basic regression model can be modified in several ways. As illustrative examples, we consider a multivariate response model and, with an additional module that interfaces with the package, a stochastic frontier analysis
History, creativity and innovation of the ‘Italia’ network. The case of Russia
No full textThis article highlights essential issues concerning Italy’s role in the world as a source of innovation and creativity through the analysis of important Russian-Italian relations and cooperation, which date back from the 14th century. The period focussed upon in this paper is the last twenty years. Migration statistics are used to describe the intellectual migration from Italy to Russia in the years from 1997 to 2016. Moreover, a case study of several Italian enterprises in Russia are presented to explain the logic of the paradoxical predominance of the food and fashion industries within Russian-Italian cooperation partnerships. The paper also highlights how the development of high-tech imports from Italy to Russia is hampered by a number of socio-cultural factors. First of all, stereotypes created through the fact that the most important wealth of the Italian economy lies in sectors oriented toward the quality of life, such as the hotel and catering, food and fashion sectors. At the same time, the achievements of the Italian science industry are generally undervalued in the field of innovative technologies in the energy sector, for example as far as “smart cities”, “smart environment” are concerned
Polisemia della convergenza in Europa
No full textNella nota si riflette sulle relazioni tra l’evoluzione delle politiche di coesione e quelle della ricerca a livello europeo. In tale quadro l’analisi dei processi che si sono avviati in Europa per il conseguimento delle convergenze ha evidenziato interessanti analogie. L’attenzione è posta sui processi di trasformazione avviati dalle diverse accezioni della convergenza: quella economica che è passata dall’obiettivo dell’eliminazione delle disparità regionali verso quello della coesione, mentre per la convergenza nel campo della ricerca si analizza il percorso progettuale che ha portato allo Spazio Europeo della Ricerca e alle implicazioni che questo ha rispetto alle Politiche di Coesione e alle innovative Convergenze Tecnologiche
Taxonomical and bionomical notes on the Sicilian endemic water beetle Ochthebius (Cobalius) biltoni (Coleoptera: Hydraenidae)
Get PDFIn this paper we present additional information on taxonomy, ecological preferences and conservation biology of the rare and poorly known Sicilian endemic Ochthebius biltoni Jäch & Delgado, 2017. It represents one of the most outstanding endemic elements of the Sicilian and Italian water beetle fauna
Two new species of the flea beetle genus Psylliodes Latreille of the montana species-group from Eastern Africa (Coleoptera: Chrysomelidae)
Get PDFIn this paper, Psylliodes afromontana sp. nov. and P. shira sp. nov., both from Eastern Africa [Kenya (Kikuyu Escarpment) and Tanzania (Kilimanjaro) respectively], are described. The two new species are attributed to the montana species-group, currently including four other wingless species occurring in the montane forests of Kenya and Tanzania: Psylliodes montana Weise, P. kikuyana Biondi, P. masai Biondi, P. manobioides Nadein. Micrographs of diagnostic characters, comprehending male and female genitalia are supplied. Ecological data for each species, including habitat preference, and phenology are also reported
New species and records of the pseudoscorpion genus Acanthocreagris from Italy (Pseudoscorpiones: Neobisiidae)
Get PDFThree new species of the genus Acanthocreagris Mahnert, 1974 are described from Lombardy (Acanthocreagris grottoloi sp. n.) and Sardinia (Acanthocreagris foghesa sp. n. and Acanthocreagris alguerensis sp. n.). Acanthocreagris sardoa (Beier, 1959) and Acanthocreagris agazzii (Beier, 1966) are redescribed respectively on specimens from Sardinia and Venetian pre-Alps and a key to adults of the Italian species of the genus is provided
Miscommunication in an investment game
No full textTo varying degrees, empirical evidence shows that non-binding messages (cheap talk) are effective in enhancing cooperative behaviors when simple games are augmented with a communication pre-stage. We focus on games where the interactions are more complex and test the effect of communication. Specifically, we consider an investment game, where players can send free-form messages before taking their choices. Differently from simple games, where subjects have just to choose whether to cooperate or not, we find that messages do not matter—on average. Our rationale is that misunderstandings are more likely to be observed in a context where the space of strategies is larger
Fully-hydrodinamic modelling supportingflood hazarda assessment snd communication: a reference framework
No full textFrom a hydraulic point of view, flood propagation in natural channels or in floodplains should be simulated using the fully-dynamic shallow water equations (SWEs), although their kinematic or diffusive approximations are still commonly used in practical applications. Indeed, only the use of the fully dynamics equations, formulated in a conservative form, allows the correct treatment of localized hydraulic phenomena and regime changes, factors that are very important for risk assessment. Currents originated by dam break phenomena are a field of study where these localized phenomena arise in a preponderant way. Until a few decades ago, the SWE were essentially developed following a one-dimensional approach, using various schematization and numerical tricks for describing the propagation in floodplain areas. The reasons why the 1-D approach was the preferred one were twofold: the lack of high-resolution topographic data for the detailed description of the hydraulic processes across the section and the limited computational efforts. Nowadays, the importance of these aspects are dramatically reduced and the use of the two-dimensional SWEs starts to be considered as the reference approach for flood propagation studies. Although the use of the fully dynamic wave equations may generate accurate results, the complexity of the associated numerical solvers and their computational times favored the development of simplified approach whose reliability is questionable especially for urban flood simulation. LiDAR data availability and the development of high performance computing technology allow the researchers to develop also flood simulations at the basin scale based on the 2D fully dynamic shallow water equations. In simulations like these, it is not very simple to achieve stable computations in presence of very shallow depths over abrupt changes of the bottom slopes and dry/wet interfaces. However, the significant improvements made in the river flows modeling, flood propagation and dam breaking flows allowed one to obtain stable results also in these complex situations. So a lot of work has been carried out in the context of the hydraulic numerical simulations for flood mapping in order to fulfill the European Floods Directive. However, it should be born in mind that the Directive itself requires to take care of risk communication with the people involved, encouraging the active involvement of the interested parties in the development of flood management plans. The integration of the classic 2-D flood maps, obtained using the models mentioned before, with 3-D representations of flood inundations using virtual reality techniques might allow non-expert public an adequate perception of the flooding impact. Following all these considerations, the paper reviews the current state-of-the-art for hydraulic modelling of floods, focusing on the above-mentioned topics and providing practical suggestions for flood hazard assessment and communications
Biodiversity of the endangered coastal beetle Scarites laevigatus: is the northern Adriatic population a geographical subspecies or a case of introgressive hybridisation? (Coleoptera: Carabidae)
Get PDFThe ground beetle Scarites laevigatus Fabricius, 1792 is a specialized predator occurring in the Mediterranean sandy shores, currently threatened with disappearance due to the widespread modification of beach ecosystems. The present study purposes a morphological analysis of the northern Adriatic form, described by Puel in 1938 as a subspecies with the name venetianus, in comparison with the typical form of this taxon and S. terricola. The examination of pronotum, elytra, body shape, male genitalia and wing development, suggests that the studied population is different from the nominotypical form and might originate from the introgressive hybridisation of S. terricola with the north Adriatic populations of S. laevigatus. This hypothesis is discussed in the light of current knowledge of the systematics and ecology of the putative parent species