107 research outputs found

    The use of technical ceramics in early Egyptian glass-making

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    We present a detailed description of the layered structure developing in the walls of Egyptian Late Bronze Age glass-making vessels, and in similar vessels successfully replicated in laboratory experiments. The analyses show that this layered discoloration and change in ceramic composition is due to the interaction of the glass batch with the vessel during firing. The formation of this visually striking and easy to recognise pattern is due to the chloride content of primary glass batches and does not occur in vessels used to re-melt existing glass. Thus, we argue that these discolorations can be used as a reliable and easy field guide to identify glassmaking waste among Late Bronze Age ceramic assemblages, hopefully increasing the currently very small number of identified LBA glassmaking workshops

    Lisht as a New Kingdom glass-making site with its own chemical signature

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    Lisht is one of a few New Kingdom sites with known glass-working debris. Here, we present evidence for the primary production of glass at Lisht, including crucible fragments and semi-finished glass. We also provide 12 new chemical analyses of glass from Lisht, including trace elements. We argue that the glass made at Lisht has a specific chemical signature within the broader range of Late Bronze Age glass compositions from Egypt, further underlining the former existence of primary glass production there and offering the possibility of identifying Lisht-made glass elsewhere in Egypt and beyond

    Experimental Evidence of a Haldane Gap in an S = 2 Quasi-linear Chain Antiferromagnet

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    The magnetic susceptibility of the S=2S = 2 quasi-linear chain Heisenberg antiferromagnet (2,2′2'-bipyridine)trichloromanganese(III), MnCl_{3}(bipy), has been measured from 1.8 to 300 K with the magnetic field, H, parallel and perpendicular to the chains. The analyzed data yield g≈2g\approx 2 and J≈35J\approx 35 K. The magnetization, M, has been studied at 30 mK and 1.4 K in H up to 16 T. No evidence of long-range order is observed. Depending on crystal orientation, M≈0M\approx 0 at 30 mK until a critical field is achieved (Hc∥=1.2±0.2TH_{c\|} = 1.2\pm 0.2 T and $H_{c\bot} = 1.8\pm 0.2 T), where M increases continuously as H is increased. These results are interpreted as evidence of a Haldane gap.Comment: 11 pages, 4 figure

    Azimuthal Correlations in the Target Fragmentation Region of High Energy Nuclear Collisions

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    Results on the target mass dependence of proton and pion pseudorapidity distributions and of their azimuthal correlations in the target rapidity range −1.73≤η≤1.32-1.73 \le \eta \le 1.32 are presented. The data have been taken with the Plastic-Ball detector set-up for 4.9 GeV p + Au collisions at the Berkeley BEVALAC and for 200 A⋅A\cdotGeV/cc p-, O-, and S-induced reactions on different nuclei at the CERN-SPS. The yield of protons at backward rapidities is found to be proportional to the target mass. Although protons show a typical ``back-to-back'' correlations, a ``side-by-side'' correlation is observed for positive pions, which increases both with target mass and with impact parameter of a collision. The data can consistently be described by assuming strong rescattering phenomena including pion absorption effects in the entire excited target nucleus.Comment: 7 pages, figures included, complete postscript available at ftp://qgp.uni-muenster.de/pub/paper/azi-correlations.ps submitted to Phys. Lett.

    Critical assessment of the elemental composition of Corning archeological reference glasses by LA-ICP-MS

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    Corning archeological reference glasses A, B, C, and D have been made to simulate different historic technologies of glass production and are used as standards in historic glass investigations. In this work, nanoseconds (193, 266 nm) and femtosecond (800 nm) laser ablation were used to study the elemental composition of Corning glasses using laser ablation inductively coupled plasma mass spectrometry. The determined concentrations of 26 oxides (Li2O, B2O3, Na2O, MgO, Al2O3, SiO2, P2O5, K2O, CaO, TiO2, V2O5, Cr2O3, MnO, Fe2O3, CoO, NiO, CuO, ZnO, Rb2O, SrO, ZrO2, SnO2, Sb2O5, BaO, PbO, Bi2O3) are compared with values reported in the literature. Results show variable discrepancies between the data, with the largest differences found for Cr2O3 in Corning A; Li2O, B2O3, and Cr2O3 in Corning B; and MnO, Sb2O5, Cr2O3, and Bi2O3 in Corning C. The best agreement between the measured and literature values was found for Corning D. However, even for this reference, glass re-evaluation of the data was necessary and new values for PbO, BaO, and Bi2O3 are proposed

    Late Byzantine Mineral Soda High Alumina Glasses from Asia Minor: A New Primary Glass Production Group

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    The chemical characterisation of archaeological glass allows the discrimination between different glass groups and the identification of raw materials and technological traditions of their production. Several lines of evidence point towards the large-scale production of first millennium CE glass in a limited number of glass making factories from a mixture of Egyptian mineral soda and a locally available silica source. Fundamental changes in the manufacturing processes occurred from the eight/ninth century CE onwards, when Egyptian mineral soda was gradually replaced by soda-rich plant ash in Egypt as well as the Islamic Middle East. In order to elucidate the supply and consumption of glass during this transitional period, 31 glass samples from the assemblage found at Pergamon (Turkey) that date to the fourth to fourteenth centuries CE were analysed by electron microprobe analysis (EPMA) and by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). The statistical evaluation of the data revealed that the Byzantine glasses from Pergamon represent at least three different glass production technologies, one of which had not previously been recognised in the glass making traditions of the Mediterranean. While the chemical characteristics of the late antique and early medieval fragments confirm the current model of glass production and distribution at the time, the elemental make-up of the majority of the eighth- to fourteenth-century glasses from Pergamon indicate the existence of a late Byzantine glass type that is characterised by high alumina levels. Judging from the trace element patterns and elevated boron and lithium concentrations, these glasses were produced with a mineral soda different to the Egyptian natron from the Wadi Natrun, suggesting a possible regional Byzantine primary glass production in Asia Minor

    How to promote, improve and test adherence to scientific evidence in clinical practice

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    BACKGROUND: Negative variation in the management of patients with the same clinical condition is frequent, and affects quality of care. Recent studies indicate that single interventions are not an effective solution. We aim to demonstrate that a multifaceted strategy can favor the introduction of research into practice, and to assess its long-term effects on a set of common medical conditions exhibiting significant negative variation at our institution. METHODS: The strategy, devised and agreed upon by a multidisciplinary group, was first applied to one relevant medical condition – cerebral ischemic stroke. To test its effectiveness a quasi-experimental study was conducted, comparing an intervention group with historical controls. After validation the strategy was extended to other pathologies, and its long-term effect measured using evidence-based quality indicators. Adherence to each indicator was determined prospectively on a six-month basis for a period of at least two consecutive years. Measures are expressed as proportions with 95% confidence intervals. RESULTS: Validation findings demonstrated that the strategy improved compliance with scientific evidence: the percentage of patients who received a CT scan within 24 hours of hospital presentation rose from 56% to 75%, (χ(2 )= 7.43 p < 0.01); admissions to selected wards increased from 45% to 64%, (χ(2 )= 7.81 p < 0.01); the number of physical medicine visits within 24 hours of the request grew from 59% to 91% (χ(2 )= 14,40 p < 0.001). Over a four-year period the program was gradually applied to 14 medical conditions. Except for 3 cases, compliance with the pathway, i.e. number of eligible patients for whom data on the care process is collected, was above the minimum requirement of 75%. Indicator adherence generally exhibited a positive trend, though variability was observed both among different conditions and between different semesters for the same pathology. CONCLUSION: According to our experience, incorporation of research into practice can be favored by systematically applying a shared, multifaceted strategy, involving multidisciplinary teams supported by central coordination. Institutions should device a tailor-made approach, should train personnel on implementation strategies, and create cultural acceptance of change. Just like for experimental trials, human and economic resources should be allocated within health care services to allow the achievement of this objective

    Sequential morphological characteristics of murine fetal liver hematopoietic microenvironment in Swiss Webster mice

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    Embryonic hematopoiesis occurs via dynamic development with cells migrating into various organs. Fetal liver is the main hematopoietic organ responsible for hematopoietic cell expansion during embryologic development. We describe the morphological sequential characteristics of murine fetal liver niches that favor the settlement and migration of hematopoietic cells from 12 days post-coitum (dpc) to 0 day post-partum. Liver sections were stained with hematoxylin and eosin, Lennert’s Giemsa, Sirius Red pH 10.2, Gomori’s Reticulin, and Periodic Acid Schiff/Alcian Blue pH 1.0 and pH 2.5 and were analyzed by bright-field microscopy. Indirect imunohistochemistry for fibronectin, matrix metalloproteinase-1 (MMP-1), and MMP-9 and histochemistry for naphthol AS-D chloroacetate esterase (NCAE) were analyzed by confocal microscopy. The results showed that fibronectin was related to the promotion of hepatocyte and trabecular differentiation; reticular fibers did not appear to participate in fetal hematopoiesis but contributed to the physical support of the liver after 18 dpc. During the immature phase, hepatocytes acted as the fundamental stroma for the erythroid lineage. The appearance of myeloid cells in the liver was related to perivascular and subcapsular collagen, and NCAE preceded MMP-1 expression in neutrophils, an occurrence that appeared to contribute to their liver evasion. Thus, the murine fetal liver during ontogenesis shows two different phases: one immature and mainly endodermic (<14 dpc) and the other more developed (endodermic-mesenchymal; >15 dpc) with the maturation of hepatocytes, a better definition of trabecular pattern, and an increase in the connective tissue in the capsule, portal spaces, and liver parenchyma. The decrease of hepatic hematopoiesis (migration) coincides with hepatic maturation
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