131 research outputs found
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
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
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
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
Physical mechanical consolidation and protection of Miocenic limestone used on Mediterranean historical monuments: the case study of Pietra Cantone (southern Sardinia, Italy)
The present work aims to study the consolidating and protective chemical treatments of the Pietra Cantone, a Miocenic (lower Tortonian) limestone widely used in important monuments and historical buildings of Cagliari (southern Sardinia, Italy). Similar limestones of the same geological period have also been used in several important monuments of Mediterranean area, i.e., Malta and Gozo Islands, Matera (central Basilicata, Italy), Lecce (southern Puglia, Italy) and Balearic Islands (Spain). The Pietra Cantone limestone shows problems of chemical–physical decay, due to their petrophysical and compositional char- acteristics: high porosity (on average 28–36 vol%), low cemented muddy-carbonate matrix, presence of phyllosil- icates and sindepositional sea salts (\3%). So, after placed in the monument, this stone is easily alterable by weath- ering chemical processes (e.g., carbonate dissolution and sulfation) and also by cyclic mechanisms of crystalliza- tion/solubilization of salts and hydration/dehydration of hygroscopic phases of the clay component. To define the mineralogical-petrographic features (composition, texture) of limestone, the clay and salt crystalline phases, the optical microscope in polarized light and diffraction anal- ysis were used. To define the petrophysical characteristics (i.e., shape and size distribution of porosity, surface area(SBET), matrix microstructures, rock composition) and interactions of chemical treatments with rock, SEM–EDS analysis and N2 porosimetry with BET and BJH methods were used. To evaluate the efficacy of Na/K-silicates, ethyl silicate consolidants and protective nano-molecular silane monomer water repellent, the mechanical strengths (uni- axial compressive strength, point load and flexural resis- tance), water/helium open porosity, water absorption and vapour permeability data determined before and after the chemical treatments of the Pietra Cantone samples from monument were compared
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
Multi-Analytical Techniques to Define the Mineralogical and Petrophysical Characteristics and Provenance of Siliceous Lithic Findings: The Case Study of La Calvera Rock Shelter (Cantabria, Spain)
This archaeometric study aims at characterizing the archaeological finds belonging to the lithic industry from La Calvera rock shelter (Camaleño, Cantabria) and at hypothesizing the possible provenance of each material. The site, located in the mountainous area of Picos de Europa National Park (more than 1000 m a.s.l.) close to the megalithic complex of Peña Oviedo, is characterized by the presence of hearths and charcoal remains, ancient pottery, and a rich lithic assemblage composed of siliceous rocks dating back to >8000 BP and linked to the first Holocene occupations of the Cantabrian Mountains. For the study of the rock shelter’s lithic assemblage, a multi-analytical approach was used: SEM-EDS and XRD analyses were performed to define the microtextural characteristics of samples and to identify the amorphous/crystalline phases; physical and mechanical tests were conducted to define the petrophysical properties (density, porosity, imbibition and saturation indexes, mechanical strength) of the samples. Preliminary data of chemical compositions, obtained by portable XRF, are also presented. The results show that the different siliceous materials (quartzite, cherts, hyaline quartz) can be distinguished through the basic analytical techniques used here. In addition, most of the archaeological samples have mineralogical and petrographic features similar to the natural samples coming from nearby outcrops, corroborating the hypothesis of a local material supply. The presence of local sources of useful raw materials could have favoured the site’s occupation. Finally, the diverse compositional and textural feature of the analysed materials result in different mechanical properties (porosity, density, hardness, workability), so they likely had different uses and technical functions
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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
Nature and statistics of majority rankings in a dynamical model of preference aggregation
We present numerical results on a complex dynamical model for the aggregation
of many individual rankings of S alternatives by the pairwise majority rule
under a deliberative scenario. Agents are assumed to interact when the Kemeny
distance between their rankings is smaller than a range R. The main object of
interest is the probability that the aggregate (social) ranking is transitive
as a function of the interaction range. This quantity is known to decay fast as
S increases in the non-interacting case. Here we find that when S>4 such a
probability attains a sharp maximum when the interaction range is sufficiently
large, in which case it significantly exceeds the corresponding value for a
non-interacting system. Furthermore, the situation improves upon increasing S.
A possible microscopic mechanism leading to this counterintuitive result is
proposed and investigated.Comment: 11 page
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