The height of Denier Tournois minting in Greece (1289–1313) according to new archaeometric data

The years 1289–1313 witnessed particularly prolific minting activities at different southern and central Greek mints on behalf of different polities. The coin issues are of great economic and political relevance, and therefore of interest to modern historians. Our understanding of these is based on traditional sources, either numismatic (types and finds), or historical. This paper aims to investigate the possibilities of adding further details to the picture through archaeometry. Specifically, tournois pennies of the three main mints of the region (Clarentza, Thebes, Naupaktos) excavated at Ancient Corinth were analysed according to two different non-destructive methods, X-ray fluorescence spectrometry (XRF) and laser-induced breakdown spectroscopy (LIBS). The resulting relative silver percentages and the fingerprints of the trace elements have supported our attempts to put the different coin types in chronological order and to add detail to the context and intent for each one of these. A vivid picture of monetary production emerges. The different issuing authorities were usually intent on maintaining a decent standard while variously trying to put pressure on rivals or to harmonise their productions with their allies. All the analysed mints were commercial in character, though they were subject to the great political changes affecting Greece in this period, the ambitions of the Angevin dynasty, the various challenges which it faced in Athens, the Peloponnese and the western Mainland, and finally the destructive arrival of the Catalans. In times of need, specifically military, these same mints could therefore rely on further bullion which reached them through internal or external political channels

Materials analyses of pyrotechnological objects from LBA Tiryns, Greece, by means of Laser-Induced Breakdown Spectroscopy (LIBS): results and a critical assessment of the method

Horizon 2020(H2020)646667Classical & Mediterranean ArchaeologyArtefact studie

Development of a methodology for the characterisation and assessment of biodeteriogens on archaeological surfaces by use of a portable LED-induced fluorescence instrument

Abstract The present study focuses on the development of a fast, non-invasive methodology, appropriate for the detection and characterization of biodeterioration present on the surface of archaeological/historical stone objects and monuments, by exploiting the characteristic fluorescence emission of biological deposits. Fluorescence spectra were collected by use of a portable LED (Light Emitting Diode)-Induced Fluorescence (LED-IF) instrument. Three limestone fragments and one mortar fragment, from different monuments in Greece, presenting various types of biodeterioration on their surface, have been investigated in the laboratory. First, fluorescence emission spectra were acquired with a benchtop laboratory spectrofluorometer in order to select the optimum excitation wavelengths for the fluorophores present in the biological crust. An evaluation of the portable LED-IF instrument was conducted by assessing the performance of its optical components and different LED excitation sources, while an investigation of several experimental parameters on the fluorescence signal was also performed. Furthermore, issues related to the efficiency of detection and identification of biological growth have been studied, such as the effect of sample surface wetting on the fluorescence signal. The results of the present study demonstrate that the LED-IF instrument can be used for a fast and reliable assessment of the presence of biodeterioration on monuments

Extensive elemental mapping unlocks Mg/Ca ratios as climate proxy in seasonal records of Mediterranean limpets

Elemental analysis of biogeochemical archives is an established technique used to study climate in a range of applications, including ocean circulation, glacial/interglacial climates, and anthropogenic climate change. Data from mollusc archives are especially important because of their global abundance and sub-annual resolution. Despite this potential, they are underrepresented among palaeoclimate studies, due to enigmatic physiological influences skewing the elemental record. Understanding the patterns behind these influences will improve data interpretation and lead to the development of new climate proxies. Here, we show for the first time that extensive spatial mapping of multiple mollusc specimens using Laser Induced Breakdown Spectroscopy (LIBS) across a wider region can resolve enigmatic patterns within the elemental record caused by physiological influences. 2D elemental (Mg/Ca) maps of whole limpet shells (Patella caerulea) from across the Mediterranean revealed patterns of variability within individual mollusc records as well as within isochronous parts of specimens. By registering and quantifying these patterns, we established previously uninterpretable correlations with temperature (R2 > 0.8, p < 0.01). This outcome redefines the possibilities of accessing sub-annual climate proxies and presents the means to assess annual temperature ranges using oxygen isotope analysis requiring only 2 samples per shell

Molecular hydrogen ion elimination from alkyl iodides under strong laser beam irradiation

The elimination of H2+ from alkyl iodides under strong (up to 5 × 1015 W cm−2) laser irradiation is studied by means of time-of-flight mass spectrometry. The study has been performed by using 60 fs (λ = 800 nm) and 35 ps (λ = 1064, 532, 355 and 266 nm) laser pulses. It is concluded that the H2+ ions are ejected from ionic states via Coulomb explosion processes. The molecular rearrangement leading to H2+ formation is attributed to a tunneling process through a H transfer barrier. For the case of methyl iodide, about 10% of the doubly charged parent ions undergo molecular rearrangement. From a comparison of the H2+/H+ ion yield ratio of the studied molecules, it turns out that the H2+ formation from H atoms bonded to a terminal carbon atom is more efficient than that arising from H atoms bonded to central C atoms of the molecular chain

Interaction mechanism of some alkyl iodides with femtosecond laser pulses

The interaction of 1-iodopropane, 2-iodopropane, 1-iodobutane, 2-iodobutane, and 1-iodopentane with (5 × 1013-5 × 1015 W/cm2) femtosecond laser fields is studied by means of a time-of-flight mass spectrometer. It is found that multiphoton ionization (MPI) and field ionization (FI) processes are involved in the molecular ionization. The contribution of these processes can be distinguished using the peak profile of the ions in the mass spectra. Thus, from the mass spectra of 2-iodoropane and 2-iodobutane, it is concluded that MPI processes are taking place even for Keldysh parameter values γ 0.3. The field ionization process depends on the characteristics of the molecular binding potential well and leads to an asymmetric charge distribution of the transient multiply charged parent ions. In the case of 1-iodobutane, the MPI processes lead to a stable doubly charged parent ion production with a laser intensity threshold higher than that found for I2+ ions. In addition, the isomers studied exhibit distinct differences in their mass spectra and their origin is discussed in detail

What do computer science students think about software piracy?

Today, software piracy is an issue of global importance. Computer science students are the future information and communication technologies professionals and it is important to study the way they approach this issue. In this article, we attempt to study attitudes, behaviours and the corresponding reasoning of computer science students in Greece regarding software piracy. The statements taken in 56 semi-structured interviews with students indicate that computer science students in Greece make intensive use of pirated software, mention as main reason for their practice the cost of genuine software, and blame the academic environment, coincidental stereotypes and their student status for this behaviour. They acknowledge the immoral character of their actions, as well as the fact that others are affected by software piracy, but they pay little attention to this action and they practically don't care. While keeping distance from software development companies, when specifically asked, they easily adopt the role of a software developer and attempt to substantiate their current and eventually future attitude out of hand. They consider software copyright laws to be inapplicable and unrealistic and fail to argue against intellectual property rights for mere digital products, such as software