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High alumina plant ash (v-Na-Al) glass bangles from Siraf: Clarifications on a Central Asian glass group (9th-14th century)
No full textInternational audienceDuring the excavations of 1966-1973 vast quantities of glass were found at Siraf in Iran on the Persian Gulf, primarily dating to the 9th-11th centuries. Some of this glass assemblage held in the Corning Museum of Glass was analysed using LA-ICP-MS, including nine glass bangle fragments dating to ca. 14th century. One was found to be of a high alumina plant ash (v-Na-Al) composition, as was a 14th-15th century glass kohl stick fragment. Further analysis of the 14th-century Siraf glass bangle collection held at the British Museum has now been analysed using LA-ICP-MS, identifying several more v-Na-Al glass bangles. Recent studies have concluded that plant ash soda glasses of Central Asian origin can most notably be characterised by elevated levels of alumina (4.5 wt%). This article reviews their glass characteristics in the context of a recently improved understanding of glass dating between the 9th-14th centuries from the historic Greater Khurasan region and particularly the v-Na-Al glass collections of Central Asia. This investigation proposes there were at least three main Central Asian glass production groups (CA1, CA2 and CA3) in circulation during this period. These differ primarily on their alumina, titanium and zirconium concentrations. Additional comparison with other relevant glass bangle collections, and v-Na-Al glass recently reviewed from south and east Africa, reveals that multiple chronologically definable subtypes of these groups may have been in circulation. Further to this, while the CA3 category remained relatively local, the CA2 type appears to have enjoyed the widest circulation along caravan routes, yet the CA1 type the widest via maritime routes. These insights offer additional information on the major characteristics of this elusive category of glass, its periods of production and an improved understanding of distribution patterns
Correlation between serum and saliva sex hormones in young female athletes
No full textInternational audienceBACKGROUND: Saliva sampling provides a practical noninvasive way for biological monitoring of steroid hormones but few studies have focused on saliva sex hormones in female athletes, and it is still unknown whether salivary concentrations are an accurate reflection of blood concentrations in this population. The aim of this study was therefore to evaluate the correlation between serum and saliva estradiol (E2) and progesterone (PG) in 10 young female athletes with normal menstrual cycle.METHODS: Thirty blood and saliva samples were taken at rest in a fasting state in order to analyze E2 and PG concentrations, during 3 different hormonal periods: Status 1: low E2 and low PG (end luteal/early follicular); Status 2: high E2 and low PG (end follicular/peri-ovulatory); Status 3: high PG (mid-luteal).RESULTS: A strong correlation was found between serum and saliva PG (r=0.914, P<0.01), whereas a weaker but still significant relationship was observed between serum and saliva E2 (r=0.755, P<0.01). The most significant correlations obtained for E2 were during Status 2 (r=0.941, P<0.01) and during Status 3 for PG (r=0.817, P<0.01).CONCLUSIONS: Although it remains challenging to produce precise identification with only saliva samples for each menstrual cycle phase, results seem to show that saliva can provide a convenient substitute to serum for sex hormones in female athletes during longitudinal monitoring. This is of particular interest in this population, with the number of female athletes suffering from an altered menstrual cycle, sometimes even during regular menstruation
Adjusting the electrode surface functionality to improve the cell voltage of aqueous electrolyte carbon/carbon supercapacitors
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The Graph Coloring Game on 4 × n-Grids
No full textInternational audienceThe graph coloring game is a famous two-player game (re)introduced by Bodlaender in 1991. Given a graph G and k ∈ N, Alice and Bob alternately (starting with Alice) color an uncolored vertex with some color in {1, • • • , k} such that no two adjacent vertices receive a same color. If eventually all vertices are colored, then Alice wins and Bob wins otherwise. The game chromatic number χg(G) is the smallest integer k such that Alice has a winning strategy with k colors in G. It has been recently (2020) shown that, given a graph G and k ∈ N, deciding whether χg(G) ≤ k is PSPACE-complete. Surprisingly, this parameter is not well understood even in "simple" graph classes. Let Pn denote the path with n ≥ 1 vertices. For instance, in the case of Cartesian grids, it is easy to show that χg(Pm□Pn) ≤ 5 since χg(G) ≤ ∆ + 1 for any graph G with maximum degree ∆. However, the exact value is only known for small values of m, namely χg(P1□Pn) = 3, χg(P2□Pn) = 4 and χg(P3□Pn) = 4 for n ≥ 4 [Raspaud, Wu, 2009]. Here, we prove that, for every n ≥ 18, χg(P4□Pn) = 4.</div
The Silver Coinages of Achaian and Aitolian Federal States
No full textInternational audienceThe numismatic study and elemental analyses by LA-ICP-MS of the Hellenistic-period Aitolian, Peloponnesian, Boiotian, and Thessalian Federations, focusing on Athenian and Macedonian coins, which was recently carried out as part of the French-German KOINON project, suggest that the Achaian cities enjoyed an unexpected liberty over the way that the metal alloy was prepared. Federal authorities may well have controlled the final product, but the minting seems to have been done by the cities and not by a central mint. In contrast, the Aitolian Koinon struck its coinage in a central mint. Throughout this period of production, after 338–150 bc, the weight and the alloy of the coins — generally of better fineness than the Achaian coins — are constant, despite the economic difficulties in the last period of their coinage
Tracing Roman Gold Stocks with LA-ICP-MS Analysis of Coins from the Second Punic War to the End of the First Century ad
No full textInternational audienceGold coinage was a latecomer in Roman monetary history and large issues remained rare until the age of Caesar. After Caesar, however, gold coinage became a regular feature of the Roman monetary system. A large data set of LA-ICP-MS analyses of Roman gold coins from the third century bc to the end of the first century ad sheds light on the development of gold coinage under the Republic and the Early Empire, as old hypotheses are reassessed
Money and Mid-Republican Rome
No full textInternational audienceRome’s mid-republican period is back in the centre of attention. Roman money and coinage, however, are largely absent from the debate. As this field has seen important developments in recent years, this paper surveys recent research in order to explore how numismatic sources can contribute to our understanding of this formative period in Roman history. First, we present an overview of these new developments, which we then contextualise in the framework of the Roman economy, Roman state formation and the development of a distinct Roman identity. We argue for a development from coinage irregularly commissioned by individual Roman magistrates to a regular Roman state coinage; from haphazard production often outside Rome to large-scale and more regular coordinated production clearly institutionalised within the Roman state, with a distinct Roman appearance. We propose to recognise two principal moments of acceleration in this process: around 240 and, above all, 210 b.c.e. , and show how these insights relate to broader debates on mid-republican Rome
Laser Spectroscopy and Optical Emission Spectroscopy study on a water-vapor Hall thruster
No full textInternational audienceHall thrusters (HTs) are one of the most widely used electric propulsion technologies for satellites. Xenon has long been the standard propellant because of its high atomic mass, low ionization energy, and inert nature, allowing HTs to reach efficiencies above 50%. However, its rising cost has motivated researchers and space agencies worldwide to explore cheaper alternatives. Water has emerged as a promising option: it is inexpensive, non-toxic, and abundant in the solar system, making it suitable for interplanetary missions. This work is the result of a collaboration with the University of Tokyo and the ICARE laboratory of the CNRS. The two thrusters used for the experiments are the ISCT200 and the water-vapor Hall Thruster (WVHT), which belong to the ICARE laboratory in Orléans and the University of Tokyo respectively. Optical Emission Spectroscopy (OES) and Laser-Induced Fluorescence (LIF) were employed to gain deeper insights into the physics of the water vapor discharge. The LIF diagnostic bench will be presented alongside the fluidic system, which allows the thruster to operate at a constant water vapor flow rate. Optical Emission Spectroscopy (OES) enables the identification of the species present within the plasma. The Balmer line transition of the hydrogen atom (H*) at 656.281 nm appears to be the dominant feature, although emission lines from oxygen atom are also observed. The Hall Thruster was operated with a xenon-water mixture, with a high-water fraction, and the Laser-Induced Fluorescence (LIF) diagnostic system has been implemented to excite xenon ions. Xenon ions are probed in the 5d 2 [4] 7/2 metastable level, with an excitation wavelength of 834.724 nm (in air) and the resulting fluorescence was detected at 541.91 nm
