A Note on Bayesian Model Selection for Discrete Data Using Proper Scoring Rules

We consider the problem of choosing between parametric models for a discrete observable, taking a Bayesian approach in which the within-model prior distributions are allowed to be improper. In order to avoid the ambiguity in the marginal likelihood function in such a case, we apply a homogeneous scoring rule. For the particular case of distinguishing between Poisson and Negative Binomial models, we conduct simulations that indicate that, applied prequentially, the method will consistently select the true model.Comment: 8 pages, 2 figure

The church of St. Saturnino in Cagliari, Sardinia, reading the levels of history through the use of digital survey and the petrophysical study of materials

The most ancient church in Cagliari is dedicated to Saint Saturno (commonly named Saint Saturnino), the first indications about this church came from the sixth century, but the building arrived to our time is only a part of the original one and it rises over the ruins of previous structures, inside a a walled area with the presence of a Palaeo-Christian necropolis. The original Greek cross plan with a transept and a semi-spherical dome; has seen meaningful transformations in time, with the partial destruction of large parts of the building. All the four arms had a nave and two aisles, but the current church consists only of the dome-covered area and of the eastern arm, with a nave and two aisles. The whole church shows very interesting parts coming from previous architectures of the Roman age, a rich catalog of rich materials and details. In summer 2013, a collaboration between the Departments of Chemical and Geological Sciences from Cagliari and the one of Architecture from Florence brought to the realization of a detailed study about this ancient church. The whole building and its surrounding area were surveyed with the following methods: photography, 3D Laser Scanner for the whole interior and exterior parts, 3D photogrammetry of a selected set of stone surface samples, direct sampling of representative rocks for geochemical and petrophysical analysis. All data were then treated and analyzed to deepen the knowledge about the most meaningful aspects of different construction techniques and use of materials, provenance of raw materials, stone and structure alterations. As the result, a base was created to read common behaviors, design choices, recursive constructive solutions, and the “models” guiding the ancient intentions. This contribution will present the progress state of this research and its results

Relations between static-structural aspects, construction phases and building materials of San Saturnino Basilica (Cagliari, Italy)

The construction site was used several times: in a first phase, in the republican era of Roman domination it hosted, probably, a temple whose height could reach 25 meters; in a second phase, during the Roman Empire, it was used as a burial area. Then around IV-V century AD a first Christian Basilica made of a naved building with an apse was built there, at the center of a large monastery. Subsequently in a third phase in VI century AD a Byzantine Martyrium, with a Greek cross-shaped plan, was built: the central part of it, supporting a dome is still standing. Finally after 1089 the church was given to Marsilian monks who deeply renovated it and changed its shape converting the plan to a Latin cross. A macroscopic material analysis shows the presence of various rocks, whose use appears to be inhomogeneous during all construction phases. Sedimentary rocks (limestones, sandstones, calcarenites etc belonging to local geological formations) are generally used for masonry structures. Marbles, mostly coming from abroad and previously used in Roman buildings have been adopted for architectural elements (columns, capitals, and so on). At a lower extent there are masonry blocks in Oligo-Miocenic volcanic rocks and seldom stone materials which are not originally from Sardinia. Both mineralogical and petrographic tests (e.g. XRF, XRD) and the most important physical properties (porosity, density, water absorption coefficients, compressive, flexural and tensile strength, etc) show that many of the more representative samples of rock materials (like limestonss, calcarenits) are often highly decayed, with a corresponding reduction of their mechanical strength. A structural analysis is particularly useful for helping in clarifying the historical evolution of the building, checking reconstruction hypotheses and assessing the true residual strength of the more important parts. An example, a FEM analysis of the Byzantine domed part is presented here

Romanesque and territory. The construction materials of Sardinian medieval churches: new approaches to the valorization, conservation and restoration

This paper is intended to illustrate a multidisciplinary research project devoted to the study of the constructive materials of the Romanesque churches in Sardinia during the “Giudicati” period (11th -13th centuries). The project focuses on the relationship between a selection of monuments and their territory, both from a historical-architectural perspective and from a more modern perspective addressing future restoration works. The methodologies of the traditional art-historical research (study of bibliographic, epigraphic and archival sources, formal reading of artifacts) are flanked by new technologies: digital surveys executed with a 3D laser-scanner, analyses of the materials (stones, mortars, bricks) with different instrumental methods: X-ray fluorescence (XRF) and inductively coupled mass spectrometry (ICP-MS) for chemical composition, X-ray diffractometer (XRD) to determine the alteration phases (e.g., soluble salts), optical microscopy and electronic (SEM) to study textures, mineral assemblages and microstructures, termogravimetric/differential scanning, calorimetric analysis (TG/DTA) for the composition of the binder mortars. This multidisciplinary approach allows the achieving of important results in an archaeometric context: 1) from a historical point of view, with the possible identification of ancient traffics, trade routes, sources of raw materials, construction phases, wall textures; 2) from a conservative point of view, by studying chemical and physical weathering processes of stone materials compatible for replacement in case of future restoration works. Sardinian Romanesque architectural heritage is particularly remarkable: about 200 churches of different types and sizes, with the almost exclusive use of cut stones. Bi- or poly-chromy, deriving from the use of different building materials, characterizes many of these monuments, becoming also a vehicle for political and cultural meanings. The paper will present some case studies aimed to illustrate the progress of the project and the results achieved

How does informational heterogeneity affect the quality of forecasts?

We investigate a toy model of inductive interacting agents aiming to forecast a continuous, exogenous random variable E. Private information on E is spread heterogeneously across agents. Herding turns out to be the preferred forecasting mechanism when heterogeneity is maximal. However in such conditions aggregating information efficiently is hard even in the presence of learning, as the herding ratio rises significantly above the efficient-market expectation of 1 and remarkably close to the empirically observed values. We also study how different parameters (interaction range, learning rate, cost of information and score memory) may affect this scenario and improve efficiency in the hard phase.Comment: 11 pages, 5 figures, updated version (to appear in Physica A

Decolonising Arabic language teaching: a case study

Since the early 2000s Arabic has become an increasingly popular language at academic level across Europe and North America, with high numbers of students enrolling on a variety of programmes offering Modern Standard Arabic – as well as local varieties of Arabic, commonly known as ‘āmmiyya – as the target language (Dickins and Watson 2006, 108; Ryding 2006, 13; Mohamed 2021b, 59). The increasingly high demand for this language has resulted in unprecedented progress in the variety of learning materials available for both teachers and learners. Such developments have largely taken place in the United States, where most textbooks such as the Al-Kitaab series are designed and printed. This paper employs decolonisation and post-colonial theory to look at the ideological implications of the political agendas implicit in popular and widely adopted textbooks and their proposed content for teaching Arabic as a foreign language. Relevant examples from the Al-Kitaab series – one of the most successful and widely adopted textbooks at university level in the UK – show the role of Arabic language teaching materials in perpetuating patterns of European and North American cultural hegemony, making the case for rethinking Arabic language teaching at academic level

Decolonising Arabic Language Teaching: A Case Study

Since the early 2000s Arabic has become an increasingly popular language at academic level across Europe and North America, with high numbers of students enrolling on a variety of programmes offering Modern Standard Arabic – as well as local varieties of Arabic, commonly known as ‘āmmiyya – as the target language (Dickins and Watson 2006, 108; Ryding 2006, 13; Mohamed 2021b, 59). The increasingly high demand for this language has resulted in unprecedented progress in the variety of learning materials available for both teachers and learners. Such developments have largely taken place in the United States, where most textbooks such as the Al-Kitaab series are designed and printed. This paper employs decolonisation and post-colonial theory to look at the ideological implications of the political agendas implicit in popular and widely adopted textbooks and their proposed content for teaching Arabic as a foreign language. Relevant examples from the Al-Kitaab series – one of the most successful and widely adopted textbooks at university level in the UK – show the role of Arabic language teaching materials in perpetuating patterns of European and North American cultural hegemony, making the case for rethinking Arabic language teaching at academic level

Impact of considering education and health-care electrical demand to the electrification plan of Kenya

LAUREA MAGISTRALEQuesto progetto nasce da una collaborazione decennale tra la Technical University of Kenya e il Politecnico di Milano; la natura di questo partenariato si basa su temi quali la cooperazione internazionale e l'energia per lo sviluppo. La ricerca ha come scopo quello di valutare l'impatto dell'uso dell’energia elettrica sui servizi pubblici, in particolare assistenza sanitaria e istruzione, sul piano dell’ elettrificazione nazionale, al fine di raggiungere il totale accesso all'elettricità per la popolazione Keniota. Il primo obiettivo della tesi e’ quello di stimare l'effettiva domanda elettrica del settore dell'istruzione e della salute nelle aree rurali del paese. Questo obiettivo è stato raggiunto utilizzando un software open source, chiamato RAMP, sviluppato dal dipartimento di energia del Politecnico di Milano. Lo strumento ha ricevuto come dati di input quelli raccolti durante un'attività di indagine condotta in alcune aree remote del Kenya. Infatti, l'attenzione si è concentrata principalmente sull'elettrificazione rurale, dove la maggior parte della popolazione non ha ancora avuto accesso a questo servizio indispensabile. Il secondo obiettivo del progetto e’ quello di valutare la migliore soluzione, economicamente parlando, per elettrificare quelle parti del Kenya in cui ancora manca l'accesso all'elettricità. Questo scopo è stato raggiunto utilizzando OnSSET, un software open source sviluppato dal Royal Institute of Technology di Stoccolma. I risultati dello studio mostrano come la considerazione della salute e dell'educazione nella domanda elettrica nazionale, sommata alla richiesta degli households già precedentemente considerata, ha spostato la soluzione ottimale da una tecnologia Stan-Alone a un sistema Micro-Grid. Entrambe le soluzioni off-grid sono basate su una fonte fotovoltaica, incentivando il governo a sfruttare maggiormente questa risorsa rinnovabile ed altamente disponibile sul territorio.This study arises from a ten-year collaboration between Technical University of Kenya and Politecnico di Milano; the nature of this partnership is based on themes as international cooperation and energy for development. The purpose of this research was to evaluate the impact of considering community use of electricity, as health-care and education, to the national electrification plan, in order to reach 100% of electricity access for the Kenyan population. The first goal of the thesis was to estimate the actual electrification demand of the education and health sector in rural area of the country. This objective was achieved by using an open source software, called RAMP, developed by the energy department of Politecnico of Milano. The tool received as input data collected during an activity of survey carried out in remote areas of Kenya. Indeed, the attention was focused principally on the rural electrification, where the biggest part of population still lack access to electricity. The second goal of the project was to evaluate the best solution, economically speaking, to electrify those parts of Kenya that still are missing electricity’s access. This purpose was reached by using OnSSET, and open-source software developed by the Royal Institute of Technology of Stockholm. Results of the study show that considering health and education in the electrical demand of the nation, added to the already considered households’ demand, shifted the optimal solution from a Stan-Alone technology to a Micro-Grid system. Both offgrid solutions were based on a photovoltaic source, giving to the government an advice to exploit more this highly available renewable resource

The potential of speleothems from Western Europe as recorders of regional climate: a critical assessment of the SISAL database

Western Europe is the region with the highest density of published speleothem δ18O (δ18Ospel) records worldwide. Here, we review these records in light of the recent publication of the Speleothem Isotopes Synthesis and AnaLysis (SISAL) database. We investigate how representative the spatial and temporal distribution of the available records is for climate in Western Europe and review potential sites and strategies for future studies. We show that spatial trends in precipitation δ18O are mirrored in the speleothems, providing means to better constrain the factors influencing δ18Ospel at a specific location. Coherent regional δ18Ospel trends are found over stadial-interstadial transitions of the last glacial, especially in high altitude Alpine records, where this has been attributed to a strong temperature control of δ18Ospel. During the Holocene, regional trends are less clearly expressed, due to lower signal-to-noise ratios in δ18Ospel, but can potentially be extracted with the use of statistical methods. This first assessment highlights the potential of the European region for speleothem palaeoclimate reconstruction, while underpinning the importance of knowing local factors for a correct interpretation of δ18Ospel

A petro-chemical study of ancient mortars from the archaeological site of Kyme (Turkey)

Fourteen samples of ancient mortars (joint mortars and plasters) from the archaeological site of Kyme (Turkey) were studied by optical microscopy (OM), X-ray fluorescence (XRF), X-ray powder diffraction (XRPD), scanning electron microscopy (SEM-EDS) and micro- Raman spectroscopy to obtain information about their composition.The study allowed us to identify a new type of plaster inside the archaeological site of Kyme, not detected by previous studies of this site, in which vegetable fibers were intentionally added to the mixture. The combination of a petrographic analysis on thin sections by polarized light microscopy with a chemical analysis, has allowed us to highlight similarities and differences between the mortars and to get information about the evolution of constructive techniques in the archaeological area