Chaotic Free-Space Laser Communication over Turbulent Channel

The dynamics of errors caused by atmospheric turbulence in a self-synchronizing chaos based communication system that stably transmits information over a $\sim$5 km free-space laser link is studied experimentally. Binary information is transmitted using a chaotic sequence of short-term pulses as carrier. The information signal slightly shifts the chaotic time position of each pulse depending on the information bit. We report the results of an experimental analysis of the atmospheric turbulence in the channel and the impact of turbulence on the Bit-Error-Rate (BER) performance of this chaos based communication system.Comment: 4 pages, 5 figure

Relationship Between Anti-DFS70 Autoantibodies and Oxidative Stress

Background: The anti-DFS70 autoantibodies are one of the most commonly and widely described agent of unknown clinical significance, frequently detected in healthy individuals. It is not known whether the DFS70 autoantibodies are protective or pathogenic. One of the factors suspected of inducing the formation of anti-DFS70 antibodies is increased oxidative stress. We evaluated the coexistence of anti-DFS70 antibodies with selected markers of oxidative stress and investigated whether these antibodies could be considered as indirect markers of oxidative stress. Methods: The intensity of oxidative stress was measured in all samples via indices of free-radical damage to lipids and proteins such as total oxidant status (TOS), concentrations of lipid hydroperoxides (LPH), lipofuscin (LPS), and malondialdehyde (MDA). The parameters of the non-enzymatic antioxidant system, such as total antioxidant status (TAS) and uric acid concentration (UA), were also measured, as well as the activity of superoxide dismutase (SOD). Based on TOS and TAS values, the oxidative stress index (OSI) was calculated. All samples were also tested with indirect immunofluorescence assay (IFA) and 357 samples were selected for direct monospecific anti DFS70 enzyme-linked immunosorbent assay (ELISA) testing. Results: The anti-DFS70 antibodies were confirmed by ELISA test in 21.29% of samples. Compared with anti-DFS70 negative samples we observed 23% lower concentration of LPH (P =.038) and 11% lower concentration of UA (P =.005). TOS was 20% lower (P =.014). The activity of SOD was up to 5% higher (P =.037). The Pearson correlation showed weak negative correlation for LPH, UA, and TOS and a weak positive correlation for SOD activity. Conclusion: In samples positive for the anti-DFS70 antibody a decreased level of oxidative stress was observed, especially in the case of samples with a high antibody titer. Anti-DFS70 antibodies can be considered as an indirect marker of reduced oxidative stress or a marker indicating the recent intensification of antioxidant processes

Recherches dans les carrières de calcarénite (ammouda) de la région de Malia

International audienc

Recherches dans les carrières de calcarénite (ammouda) de la région de Malia

International audienc

Recherches dans les carrières de calcarénite (ammouda) de la région de Malia

International audienc

Evolution des paysages et histoire de l'occupation d'Érétrie (Eubée, Grèce) du Bronze ancien à l'époque romaine

International audienc

Eretrian ceramic products through time: Investigating the early history of a Greek metropolis

Eretria, an important ancient Greek polis with a rich Bronze Age past, was among the first colonial and commercial powers in the ancient world that founded already in the 8th c. BC a number of colonies and trading posts across the Aegean and the Mediterranean. In the context of a diachronic investigation of Eretrian pottery production and supply from the Early Bronze Age to the Roman period, a large number of pottery samples and geological materials have been analysed. The current article summarises the results of the analyses of the Bronze Age pottery from the site, comprising 151 pottery samples carefully selected from stratified deposits, which have been examined through petrographic and chemical (WD-XRF) analyses and compared to geological materials and experimental ceramic briquettes. Overall, the current evidence for local pottery production indicates that during the third and the early second millennia BC no dramatic change occurred in the exploitation of raw materials in Eretria for pottery production, in spite of conspicuous stylistic and technological transformations. The first possible change in raw material sources, which occurs in the Middle Helladic period and affects coarse wares only, corresponds with a major break in the site occupation. Unlike local products, most imported fabrics do not show continuity through time, indicating changes in the direction of external relationships in Eretria

Mid- to Late Holocene shoreline reconstruction and human occupation in Ancient Eretria (South Central Euboea, Greece)

Few studies have aimed to reconstruct landscape change in the area of Eretria (South Central Euboea, Greece) during the last 6000 years. The aim of this paper is to partially fill in this gap by examining the interaction be- tween Mid- to Late Holocene shoreline evolution and human occupation, which is documented in the area from the Late Neolithic to the Late Roman period (with discontinuities). Evidence of shoreline displacements is derived from the study of five boreholes (maximum depth of 5.25 m below the surface) drilled in the lowlands of Eretria. Based on sedimentological analyses and micro/macrofaunal identifications, different facies have been identified in the cores and which reveal typical features of deltaic progradation with marine, lagoonal, fluvio- deltaic and fluvial environments. In addition, a chronostratigraphy has been obtained based on 20 AMS 14C radio- carbon dates performed on samples of plant remains and marine/lagoonal shells found in situ. The main sequences of landscape reconstruction in the plain of Eretria can be summarized as follows: a marine environ- ment predominated from ca. 4000 to 3200 cal. BC and a gradual transition to shallow marine conditions is ob- served ca. 3200-3000 cal. BC due to the general context of deltaic progradation west of the ancient city. Subsequently, from ca. 3000 to 2000 cal. BC, a lagoon occupied the area in the vicinity of the Temple of Apollo and the settlement's development was restricted to several fluvio-deltaic levees, thus severely limiting human activities in the plain. From ca. 2000 to 800 cal. BC, a phase of shallow marine presence prevailed and constrained settlement on higher ground, forcing abandonment of the major part of the plain. Finally, since the eighth century BC, the sea has regressed southward and created the modern landscape

Géoarchéologie des paysages littoraux le long du golfe sud‑eubéen (île d’Eubée, Grèce)au cours de l’Holocène (Geoarchaeology of coastal landscapes along the south Euboean gulf (Euboea Island, Greece) during the Holocene)

A joint geoarchaeological research programme developed by CNRS, together with the Swiss School of Archaeology in Greece, the British School at Athens, the Harokopiou University of Athens and the local archaeological services (Ephorate of Antiquities of Euboea), has endeavored to reconstruct the Holocene coastal landscape evolution in the vicinity of major archaeological sites along the southwest shoreline of Euboea Island (Greece), together with the history of human occupation. The sites of Lefkandi, Eretria, Amarynthos and the Lilas delta were selected for their rich archaeological record. During the work, 26 boreholes were drilled in the corresponding coastal plains. Laboratory analysis comprised the identification of mollusks and ostracods, together with granulometric analyses of the sediments, to characterize the different sedimentary environments. 71 radiocarbon dates provided a robust chronostratigraphic framework for the studied sites. In addition, a pollen sequence from Amarynthos was studied to reconstruct the vegetation history from ca. 5.500-4.300 (Neolithic times) and from 1.100-850 cal. BC (Early Iron Age). The results enable us to: (i) Reconstruct the Holocene shoreline migrations from the Lilas delta, in the north, to Amarynthos in the south. Three major phases of shoreline progradation are recorded at the end of the IVth/beginning of the IIIrd Millennium BC, at the beginning of the Ist Millennium BC and during the Ottoman period (xvth-xixth Cent. AD), while a marine incursion occurred only in Eretria during the IInd millennium BC; ii) reconstruct the sea level curve for the last 8 millennia in the West-Central Aegean Sea. A significant role of local tectonic vertical movements (uplift) is evident, attested by the presence of several hiatuses in sedimentation; (iii) reconstruct for the first time the vegetation history in the surroundings of Amarynthos, from Neolithic times and Early Iron Age, within the broader South Aegean-Attica environmental context, which has never been achieved before. Human activities (grazing and cereal cultivation) are recorded since at least Late Neolithic times where an open landscape dominated until at least the Early Iron Age

A Nonlinear Model of Newborn EEG with Nonstationary Inputs

This paper proposes a new model of newborn EEG to simulate different components of newborn EEG, based on the interpretation of the seizure as a sequence of internally evoked potentials. (Additional details can be found in the comprehensive book on Time-Frequency Signal Analysis and Processing (see http://www.elsevier.com/locate/isbn/0080443354). In addition, the most recent upgrade of the original software package that calculates Time-Frequency Distributions and Instantaneous Frequency estimators can be downloaded from the web site: www.time-frequency.net. This was the first software developed in the field, and it was first released publicly in 1987 at the 1st ISSPA conference held in Brisbane, Australia, and then continuously updated).Newborn EEG is a complex multiple channel signal that displays nonstationary and nonlinear characteristics. Recent studies have focussed on characterizing the manifestation of seizure on the EEG for the purpose of automated seizure detection. This paper describes a novel model of newborn EEG that can be used to improve seizure detection algorithms. The new model is based on a nonlinear dynamic system; the Duffing oscillator. The Duffing oscillator is driven by a nonstationary impulse train to simulate newborn EEG seizure and white Gaussian noise to simulate newborn EEG background. The use of a nonlinear dynamic system reduces the number of parameters required in the model and produces more realistic, life-like EEG compared with existing models. This model was shown to account for 54% of the linear variation in the time domain, for seizure, and 85% of the linear variation in the frequency domain, for background. This constitutes an improvement in combined performance of 6%, with a reduction from 48 to 4 model parameters, compared to an optimized implementation of the best performing existing model