The medieval bronze doors of San Zeno, Verona: combining material analyses and art history
Ontology highlight
ABSTRACT:
SUBMITTER: Modlinger M
PROVIDER: S-EPMC10811183 | biostudies-literature | 2024 Jan
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Two 11th- and 12th-century entrance doors from the Basilica di San Marco in Venice, made of different copper alloys and woods, were non-invasively examined in situ. The chemical composition of the metals, the way in which different metal parts were joined together, the tree species used to construct the supporting structures and the age of the wood are determined. A portable ED-XRF instrument and optical microscopes were used. The doors were also photographed to produce high-resolution orthophotos and 3D models. The metal parts of the doors were made of leaded tin-bronze and quaternary Cu-Sn-Zn-Pb alloys and were mounted on a wooden multi-layer structure of larch and silver fir; the dendrochronological dates of some of the larch boards are 1965, teminus post quem.
| S-EPMC10343026 | biostudies-literature
Project description:High-resolution sediment analysis allowed us to identify two Middle Bronze Age (MBA 1, 1650-1550 cal a BCE) byre-houses at the waterlogged site of Oppeano "4D", south of Verona (Veneto region, NE Italy). The site lies in a low-lying valley incised by the Adige River in its LGM alluvial fan. In this fluvio-palustrine environment burial and taphonomic conditions were such that the archaeological record was extremely well preserved. The wooden elements making up basal parts of nine 'huts' were in fact exposed at Oppeano, and so were their internal accretion deposits. These featured finely laminated dung units deriving from the stalling of small herbivores, possibly ovicaprids, intercalated with repeated accumulations of wood ash. This was produced in large and multi-stratified hearths that were exposed within each hut. Organic petrology provided evidence of the production of wood tar inside one of the studied structures. At Oppeano 4D it was thus demonstrated that these structures were not just byres or stables, but spaces that housed humans together with animals at least during some periods of the year, hence byre-houses. The identification of byre-houses in a Middle Bronze Age settlement is key for the reconstruction of socio-economic aspects of Bronze Age economy and production systems.
| S-EPMC9432763 | biostudies-literature
Project description:We report genome-wide DNA data for 73 individuals from five archaeological sites across the Bronze and Iron Ages Southern Levant. These individuals, who share the "Canaanite" material culture, can be modeled as descending from two sources: (1) earlier local Neolithic populations and (2) populations related to the Chalcolithic Zagros or the Bronze Age Caucasus. The non-local contribution increased over time, as evinced by three outliers who can be modeled as descendants of recent migrants. We show evidence that different "Canaanite" groups genetically resemble each other more than other populations. We find that Levant-related modern populations typically have substantial ancestry coming from populations related to the Chalcolithic Zagros and the Bronze Age Southern Levant. These groups also harbor ancestry from sources we cannot fully model with the available data, highlighting the critical role of post-Bronze-Age migrations into the region over the past 3,000 years.
| S-EPMC10212583 | biostudies-literature
Project description:Na9V14O35 (η-NaxV2O5) has been synthesized via solid-state reaction in an evacuated sealed silica ampoule and tested as electroactive material for Na-ion batteries. According to powder X-ray diffraction, electron diffraction and atomic resolution scanning transmission electron microscopy, Na9V14O35 adopts a monoclinic structure consisting of layers of corner- and edge-sharing VO5 tetragonal pyramids and VO4 tetrahedra with Na cations positioned between the layers, and can be considered as sodium vanadium(IV,V) oxovanadate Na9V104.1+O19(V5+O4)4. Behavior of Na9V14O35 as a positive and negative electrode in Na half-cells was investigated by galvanostatic cycling against metallic Na, synchrotron powder X-ray diffraction and electron energy loss spectroscopy. Being charged to 4.6 V vs. Na+/Na, almost 3 Na can be extracted per Na9V14O35 formula, resulting in electrochemical capacity of ~60 mAh g-1. Upon discharge below 1 V, Na9V14O35 uptakes sodium up to Na:V = 1:1 ratio that is accompanied by drastic elongation of the separation between the layers of the VO4 tetrahedra and VO5 tetragonal pyramids and volume increase of about 31%. Below 0.25 V, the ordered layered Na9V14O35 structure transforms into a rock-salt type disordered structure and ultimately into amorphous products of a conversion reaction at 0.1 V. The discharge capacity of 490 mAh g-1 delivered at first cycle due to the conversion reaction fades with the number of charge-discharge cycles.
| S-EPMC8747075 | biostudies-literature
Project description:Decoherence plays an important role in nonadiabatic (NA) molecular dynamics (MD) simulations because it provides a physical mechanism for trajectory hopping and can alter transition rates by orders of magnitude. Generally, decoherence effects slow quantum transitions, as exemplified by the quantum Zeno effect: in the limit of infinitely fast decoherence, the transitions stop. If the measurements are not sufficiently frequent, an opposite quantum anti-Zeno effect occurs, in which the transitions are accelerated with faster decoherence. Using two common NA-MD approaches, fewest switches surface hopping and decoherence-induced surface hopping, combined with analytic examination, we demonstrate that including decoherence into NA-MD slows down NA transitions; however, many realistic systems operate in the anti-Zeno regime. Therefore, it is important that NA-MD methods describe both Zeno and anti-Zeno effects. Numerical simulations of charge trapping and relaxation in graphitic carbon nitride suggest that time-dependent NA Hamiltonians encountered in realistic systems produce robust results with respect to errors in the decoherence time, a favorable feature for NA-MD simulations.
| S-EPMC10440816 | biostudies-literature
Project description:Hoard finds from the Bronze Age have appeared all over Europe, prompting questions about their functions (either as raw materials for recycling or votive objects). The hoard trove of raw materials from Przybysław in Greater Poland is an interesting example of a discovery that is related to the foundry activities of Late Bronze Age and Early Iron Age communities (c. 600 BC). The deposit consists of fragments of raw materials that were damaged end products intended for smelting. The research included the characterisation of the material in terms of the variety of the raw materials that were used. The individual elements of the hoard were characterised in terms of their chemical compositions, microstructures, and properties. A range of modern instrumental research methods were used: metallographic macroscopic and microscopic observations by optical microscopy (OM), scanning electron microscopy (SEM), chemical-composition analysis by X-ray fluorescence spectroscopy (ED-XRF), X-ray microanalysis (EDS), and detailed crystallisation analysis by electron microscopy with an emphasis on electron backscatter diffraction (EBSD). As part of this study, model alloys were also prepared for two of the selected chemical compositions, (i.e., CuPbSn and CuPb). These alloys were analysed for their mechanical and technological properties. This research of the hoard from Przybysław (Jarocin district, Greater Poland) has contributed to the recognition and interpretation of the function and nature of the hoard by using modern research and modelling methods as a cultic raw material deposit.
| S-EPMC10780300 | biostudies-literature
Project description:Repeated measurements can slow down (the quantum Zeno effect) or speed up (the quantum anti-Zeno effect) the temporal evolution of a quantum system. In this paper, a general treatment of the quantum Zeno and anti-Zeno effects is presented which is valid for an arbitrary system-environment model in the weak system-environment coupling regime. It is shown that the effective lifetime of a quantum state that is subjected to repeated projective measurements depends on the overlap of the spectral density of the environment and a generalized 'filter function'. This filter function depends on the system-environment Hamiltonian, the state of the environment, and the measurement being performed. Our general framework is then used to study explicitly the Zeno to anti-Zeno crossover behaviour for the spin-boson model where a single two-level system is coupled to a bosonic environment. It is possible to not only reproduce results for the usual population decay case as well as for the pure dephasing model, but to also study the regime where both decay and dephasing take place. These results are then extended to many two-level systems coupled collectively to the bosonic environment to further illustrate the importance of the correct evaluation of the effective decay rate.
| S-EPMC4942788 | biostudies-literature
Project description:Quantum repeaters pave the way for long-distance quantum communications and quantum Internet, and the idea of quantum repeaters is based on entanglement swapping which requires the implementation of controlled quantum gates. Frequently measuring a quantum system affects its dynamics which is known as the quantum Zeno effect (QZE). Beyond slowing down its evolution, QZE can be used to control the dynamics of a quantum system by introducing a carefully designed set of operations between measurements. Here, we propose an entanglement swapping protocol based on QZE, which achieves almost unit fidelity. Implementation of our protocol requires only simple frequent threshold measurements and single particle rotations. We extend the proposed entanglement swapping protocol to a series of repeater stations for constructing quantum Zeno repeaters which also achieve almost unit fidelity regardless of the number of repeaters. Requiring no controlled gates, our proposal reduces the quantum circuit complexity of quantum repeaters. Our work has potential to contribute to long distance quantum communications and quantum computing via quantum Zeno effect.
| S-EPMC9468345 | biostudies-literature
Project description:Measurements in quantum mechanics can not only effectively freeze the quantum system (the quantum Zeno effect) but also accelerate the time evolution of the system (the quantum anti-Zeno effect). In studies of these effects, a quantum state is prepared repeatedly by projecting the quantum state onto the initial state. In this paper, we repeatedly prepare the initial quantum state in a different manner. Instead of only performing projective measurements, we allow unitary operations to be performed, on a very short time-scale, after each measurement. We can then repeatedly prepare the initial state by performing some projective measurement and then, after each measurement, we perform a suitable unitary operation to end up with the same initial state as before. Our objective is to find the projective measurements that minimize the effective decay rate of the quantum state. We find such optimal measurements and the corresponding decay rates for a variety of system-environment models such as the pure dephasing model and the spin-boson model. We find that there can be considerable differences between this optimized effective decay rate and the usual decay rate obtained by repeatedly projecting onto the initial state. In particular, the Zeno and anti-Zeno regimes can be considerably modified.
| S-EPMC5603598 | biostudies-literature
Project description:Painting has played a major role in human expression, evolving subject to a complex interplay of representational conventions, social interactions, and a process of historization. From individual qualitative work of art historians emerges a metanarrative that remains difficult to evaluate in its validity regarding emergent macroscopic and underlying microscopic dynamics. The full scope of granular data, the summary statistics, and consequently, also their bias simply lie beyond the cognitive limit of individual qualitative human scholarship. Yet, a more quantitative understanding is still lacking, driven by a lack of data and a persistent dominance of qualitative scholarship in art history. Here, we show that quantitative analyses of creative processes in landscape painting can shed light, provide a systematic verification, and allow for questioning the emerging metanarrative. Using a quasicanonical benchmark dataset of 14,912 landscape paintings, covering a period from the Western renaissance to contemporary art, we systematically analyze the evolution of compositional proportion via a simple yet coherent information-theoretic dissection method that captures iterations of the dominant horizontal and vertical partition directions. Tracing frequency distributions of seemingly preferred compositions across several conceptual dimensions, we find that dominant dissection ratios can serve as a meaningful signature to capture the unique compositional characteristics and systematic evolution of individual artist bodies of work, creation date time spans, and conventional style periods, while concepts of artist nationality remain problematic. Network analyses of individual artists and style periods clarify their rhizomatic confusion while uncovering three distinguished yet nonintuitive supergroups that are meaningfully clustered in time.
| S-EPMC7604435 | biostudies-literature