6,602 research outputs found

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

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    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

    Leave-one-out prediction error of systolic arterial pressure time series under paced breathing

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    In this paper we show that different physiological states and pathological conditions may be characterized in terms of predictability of time series signals from the underlying biological system. In particular we consider systolic arterial pressure time series from healthy subjects and Chronic Heart Failure patients, undergoing paced respiration. We model time series by the regularized least squares approach and quantify predictability by the leave-one-out error. We find that the entrainment mechanism connected to paced breath, that renders the arterial blood pressure signal more regular, thus more predictable, is less effective in patients, and this effect correlates with the seriousness of the heart failure. The leave-one-out error separates controls from patients and, when all orders of nonlinearity are taken into account, alive patients from patients for which cardiac death occurred

    Coupling beach ecology and macroplastics litter studies: Current trends and the way ahead

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    As sites of floating marine material deposition, sandy beaches accumulate marine litter. While research and assessment on beach litter is increasing and involves various actors (scientists, society and NGOs), there is the need to assess current and future dominant trends, directions and priorities in that research. As such, a textural co-occurrence analysis was applied to published scientific literature. Words were considered both singly and as part of compound terms related to concepts relevant to sandy beach ecology: morphodynamic state; Littoral Active Zone; indicator fauna. Litter as a compound term was also included. The main co-occurrences were found within compounds, with scarce interaction of “morphodynamic state” with the others, indicating the need for further integration of beach ecology paradigms into beached plastics studies. Three approaches are proposed to overcome the research limits highlighted: the unequivocation of terms, the consideration of adequate scales, and the attention to dynamics rather than just patterns

    Hydro‐stratigraphic conditions and human activity leading to development of a sinkhole cluster in a Mediterranean water ecosystem

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    Salento Peninsula (Apulia, southern Italy) is characterised by many active sinkholes, which represent the main geological hazard. The stretch of coastline between the village of Casalabate and Le Cesine wildlife reserve is highly affected, with a system of dunes separating the low beach from extensive wetlands, which were subject to uncontrolled urban development after reclamation. The overall morphology is characterized by flat topography, whilst from a hydrogeological standpoint, the mixing of inland freshwater with advancing brackish water favours the higher aggressivity with respect to soluble rocks, and the development of enhanced dissolution (hyperkarst). The relict landscapes within the protected areas still allow for the recognition of actively occurring sinkholes, which cause damage to houses, the road network and infrastructures. In this article the case of Aquatina di Frigole is described, where in the last 15 years numerous sinkholes have formed, with the processes still in rapid evolution. Detailed surveys allow for to identification of the mechanisms of sinkhole formation (suffusion sinkholes), the deriving cluster, and the main hydrogeological links among the different water bodies in the area. Acquatina di Frigole provides an excellent natural laboratory to observe development and evolution of sinkholes, and their relationships with the stratigraphic and hydrogeological elements

    Expression analysis of HLA-E and NKG2A and NKG2C receptors points at a role for natural killer function in ankylosing spondylitis

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    Background. Ankylosing Spondylitis (AS) is a complex chronic inflammatory disease strongly associated with the majority of HLA-B27 alleles. HLA-E are non-classical MHC class I molecules that specifically interact with the natural killer receptors NKG2A (inhibitory) and NKG2C (activating), and have been recently proposed to be involved in AS pathogenesis. Objectives: To analyze the expression of HLA-E and the CD94/NKG2 pair of receptors in HLA-B27 positive AS patients and healthy controls (HC) bearing the AS-associated, B*2705 and the non-AS-associated, B*2709 allele. Methods: The level of surface expression of HLA-E molecules on CD14 positive peripheral blood mononuclear cell was evaluated in 21 HLA-B*2705 patients with AS, 12 HLA-B*2705 HC, 12 HLA-B*2709 HC and 6 HLA-B27 negative HC, using the monoclonal antibody MEM-E/08 by quantitative cytofluorimetric analysis. The percentage and density of expression of HLA-E ligands NKG2A and NKG2C were also measured on CD3-CD56+ NK cells. Results. HLA-E expression in CD14 positive cells was significantly higher in AS patients (587.0 IQR 424-830) compared to B*2705 HC (389 IQR 251.3-440.5, p=0.0007), B*2709 HC (294.5 IQR 209.5-422, p=0.0004) and HLA-B27 negative HC (380 IQR 197.3-515.0, p=0.01). A higher number of NK cells expressing NKG2A compared to NKG2C was found in all cohort analysed as well as a higher cell surface density. Conclusion: The higher surface level of HLA-E molecules in AS patients compared to HC, concurrently with a prevalent expression of NKG2A, suggests that the crosstalk between these two molecules might play a role in AS pathogenesis accounting for the previously reported association between HLA-E and AS

    Klimaatverandering tegengaan met belasting?: een economische analyse

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    90 tot 97% van de wetenschappers zijn het met elkaar eens: klimaatverandering komt grotendeels door menselijk handelen. Wij zorgen voor toenemende CO2-uitstoot met als gevolg globale opwarming. Met klimaatbeleid proberen overheden wereldwijd een CO2-reductie te bewerkstelligen via een economische revolutie. Het publieke debat in Nederland wordt voornamelijk gedomineerd door individuele aanpassingen die men vooral afschrikt: zonnepanelen op je dak, warmtepomp op zolder en rijden in een fossielvrije auto. “Dat kan ik niet betalen!” is een breed gedeeld sentiment. Natuurlijk zijn dit belangrijke maatregelen voor nu Ă©n de toekomst, maar beseffende dat de industrie verantwoordelijk is voor een derde van de CO2-uitstoot, is het tijd om de focus van het publieke debat gedeeltelijk te verleggen. In deze economische analyse bekijken we waarom en hoe we de industrie mee kunnen nemen naar een fossielvrije toekomst

    Characterization of FCI (Fédération Cynologique Internationale) Grades for Hip Dysplasia in Five Dog Breeds

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    Simple Summary Hip dysplasia is one of the most frequently occurring orthopedic diseases in medium to large purebred dogs. For this reason, much attention is paid to screening programs for breeding animals. The Federation Cynologique Internationale uses the same evaluation criteria regardless of breed. The aim of this study was to evaluate whether or not the evolution of a hip pathology in dogs with or without dysplasia was consistent with prior scientific knowledge in five breeds. In addition, whether there were significant radiographic differences between breeds which might require a breed-specific method for assessing the grade of hip dysplasia was investigated. Evaluations of 16 radiographic parameters analyzed using the Brass method were collected from 5 breeds: Labrador Retrievers, Golden Retrievers, German Shepherd dogs, Bernese Mountain dogs, and Rottweilers. No significant changes were found among the five breeds regarding the grade of hip dysplasia; however, some significant variations were found in the individual radiographic parameters suggesting that, although the criteria regarded all breeds, there were specific alterations which could be caused by the different morphologies, aptitudes and abilities of each breed. The aim of this retrospective study was to verify whether the radiographic morphologic differences detected within the first three grades of hip dysplasia (A, B, C) of each of the five selected breeds and within the same breeds were statistically significant enough to require a breed-specific evaluation. A total of 422 technical evaluation forms of hip dysplasia (HD) in Labrador Retrievers, Golden Retrievers, Rottweilers, Bernese Mountain dogs, and German Shepherd dogs were obtained from the Federation Cynologique Internationale (FCI) archive. The data were evaluated using a descriptive statistical analysis. In Labrador Retrievers, the craniolateral acetabular rim and femoral head position were already altered in unaffected dogs; however, within the various FCI grades, the most severe changes involved the conformation of the femoral neck. All the radiographic parameters of the Golden Retriever hips changed progressively and evenly. Significant radiographic changes between FCI grades were found in the German Shepherd dogs, and the alterations involving the acetabulum were more severe and appeared earlier than in the femoral head and neck. In the Bernese Mountain dogs, the most severe alterations were in the position of the femoral head and joint space while the femoral head and neck showed no significant progression between grades. All the radiographic parameters of non-dysplastic Rottweilers were normal; however, the progression of the primary signs was similar to the other breeds, although with lower severity. In conclusion, no significant prevalence of the radiographic features was observed for any specific breed. However, significant individual breed variations in the primary radiographic parameters were found between dogs with and without dysplasia which could be useful for better understanding the consequences of biomechanical differences between breeds

    High Contrast Imaging in the Visible: First Experimental Results at the Large Binocular Telescope

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    In February 2014, the SHARK-VIS (System for High contrast And coronography from R to K at VISual bands) Forerunner, a high contrast experimental imager operating at visible wavelengths, was installed at LBT (Large Binocular Telescope). Here we report on the first results obtained by recent on-sky tests. These results show the extremely good performance of the LBT ExAO (Extreme Adaptive Optics) system at visible wavelengths, both in terms of spatial resolution and contrast achieved. Similarly to what was done by (Amara et al. 2012), we used the SHARK-VIS Forerunner data to quantitatively assess the contrast enhancement. This is done by injecting several different synthetic faint objects in the acquired data and applying the ADI (angular differential imaging) technique. A contrast of the order of 5×10−55 \times 10^{-5} is obtained at 630 nm for angular separations from the star larger than 100 mas. These results are discussed in light of the future development of SHARK-VIS and compared to those obtained by other high contrast imagers operating at similar wavelengths.Comment: Astronomical Journal - Accepted for publicatio
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