Paper Session II-C - Detection of Water in Martian Soil

The mineral composition of the Martian soil was previously characterized during NASA\u27s two Viking missions, and also on the Mars Pathfinder mission. The recent NASA MER missions will also contribute to our understanding of the composition of the Martian soil, and they will also look for evidence to indicate the presence of water in the soil at some time in the distant past. While the ongoing Mars Glob al Surveyor orbiter mission has provided (indirect) evidence for the presence of water on Mars, there have not been any direct measurements of water in the Martian soil by any lander mission. We will describe a possible method that may be used to directly detect water in the Martian soil. We will present data obtained using an instrument that we developed at NASA Kennedy Space Center to measure the dielectric properties of JSC Mars- I Martian soil simulant under dry and moist conditions, and show that this is a direct method that can be used to detect the presence of water in soil

Petrogenesis of a late-stage calc-alkaline granite in a giant S-type batholith: geochronology and Sr–Nd–Pb isotopes from the Nomatsaus granite (Donkerhoek batholith), Namibia

The late-tectonic 511.4 ± 0.6 Ma-old Nomatsaus intrusion (Donkerhoek batholith, Damara orogen, Namibia) consists of moderately peraluminous, magnesian, calc-alkalic to calcic granites similar to I-type granites worldwide. Major and trace-element variations and LREE and HREE concentrations in evolved rocks imply that the fractionated mineral assemblage includes biotite, Fe–Ti oxides, zircon, plagioclase and monazite. Increasing K2O abundance with increasing SiO2 suggests accumulation of K-feldspar; compatible with a small positive Eu anomaly in the most evolved rocks. In comparison with experimental data, the Nomatsaus granite was likely generated from meta-igneous sources of possibly dacitic composition that melted under water-undersaturated conditions (X H2O: 0.25–0.50) and at temperatures between 800 and 850 °C, compatible with the zircon and monazite saturation temperatures of 812 and 852 °C, respectively. The Nomatsaus granite has moderately radiogenic initial 87Sr/86Sr ratios (0.7067–0.7082), relatively radiogenic initial εNd values (− 2.9 to − 4.8) and moderately evolved Pb isotope ratios. Although initial Sr and Nd isotopic compositions of the granite do not vary with SiO2 or MgO contents, fSm/Nd and initial εNd values are negatively correlated indicating limited assimilation of crustal components during monazite-dominated fractional crystallization. The preferred petrogenetic model for the generation of the Nomatsaus granite involves a continent–continent collisional setting with stacking of crustal slices that in combination with high radioactive heat production rates heated the thickened crust, leading to the medium-P/high-T environment characteristic of the southern Central Zone of the Damara orogen. Such a setting promoted partial melting of metasedimentary sources during the initial stages of crustal heating, followed by the partial melting of meta-igneous rocks at mid-crustal levels at higher P–T conditions and relatively late in the orogenic evolution

Non-Extensive statistical physics properties of seismic coda waves recorded during the Santorini unrest period 2011-2012

Η περίοδος της ηφαιστειακής κρίσης στο νησί της Σαντορίνης κατά τη περίοδο 2011- 2012, οδήγησε αρκετές επιστημονικές μελέτες να εγείρουν το κρίσιμο ερώτημα, εάν η σεισμικότητα της ευρύτερης περιοχής της καλντέρας, σχετίζεται με μια επικείμενη και πιθανή ηφαιστειακή έκρηξη ή αν εκφορτίζει τη συσσωρευμένη τεκτονική ενέργεια. Στην παρούσα μεταπτυχιακή διατριβή, μελετήσαμε τα σεισμικά κύματα ουράς (Coda waves), από τα τοπικά σεισμικά γεγονότα πριν, κατά τη διάρκεια και μετά την περίοδο της ηφαιστειακή και σεισμικής κρίσης της Σαντορίνης. Τα σεισμικά κύματα ουράς, οφείλουν την παρουσία τους σε φαινόμενα σκέδασης και στην πολυπλοκότητα της κατανομής των σκεδαστών του υπεδάφους, στις ανομοιογένειες του εσωτερικού της Γης, όπως είναι οι ρωγμές και η σχιστότητα των πετρωμάτων, τα ρήγματα, στα όρια μετάβασης υλικών διαφορετικής πυκνότητας, και στις πάσης φύσεως γεωφυσικές ανομοιογένειες ως προς τις ιδιότητες των υλικών στα ανώτερα στρώματα του φλοιού της Γης. Πιο συγκεκριμένα, λάβαμε υπόψη και τις τρεις συνιστώσες των σεισμολογικών σταθμών στο νησί της Σαντορίνης και εκτιμήσαμε τη διάρκεια των σεισμικών κυμάτων ουράς, εφαρμόζοντας μια διαδικασία πέντε επιπέδων, η οποία περιλαμβάνει την αναλογία σεισμικού σήματος προς θόρυβο (SNR), τη μέθοδο τύπου βραχέως μέσου χρόνου προς μακροπρόθεσμο μέσο χρόνο (STA/LTA) στο πεδίο του χρόνου αλλά και στο αναλυτικό σήμα, όπως αυτό προκύπτει από την εφαρμογή του μετασχηματισμού Hilbert, καθώς και τον μετασχηματισμό Fourier βραχέως χρόνου (STFT), εφαρμόζοντας παράθυρο Γκαουσιανής συνάρτησης (window function). Η τελική εκτίμηση της διάρκειας των κυμάτων ουράς, επαληθεύτηκε ή και επανεκτιμήθηκε αναλογικά από τον χρήστη, εξαιτίας της ύπαρξης ισχυρού σεισμικού θορύβου. Λόγω της πολυπλοκότητας των κυμάτων ουράς, για τη μελέτη του ηφαιστειακού συμπλέγματος της Σαντορίνης, εφαρμόσαμε την θεωρία της μη εκτατικής στατιστικής φυσικής (NESP). Η προσέγγιση NESP εκφράζει την γενίκευση της στατιστικής μηχανικής των Boltzmann-Gibbs και έχει χρησιμοποιηθεί εκτενώς για την ανάλυση πολύπλοκων συστημάτων, με εμφανή χαρακτηριστικά και ιδιότητες αλληλεπίδρασης μακράς εμβέλειας, μνήμης και μορφοκλασματικότητας. Η ανάλυση και τα αποτελέσματα της παρούσας διατριβής δείχνουν ότι οι διαφορές πλάτους των διαδοχικών σημείων των σεισμικών κυμάτων ουράς (στο πεδίο του χρόνου), αποκλίνουν από το στατιστικό πρότυπο τύπου Gauss, καθώς οι αντίστοιχες συναρτήσεις πυκνότητας πιθανότητας (PDFs), μπορούν να περιγραφούν επαρκώς από κατανομές πιθανότητας που προκύπτουν από τον μη εκτατικό φορμαλισμό και πιο συγκεκριμένα από την κατανομή q-Gaussian. Επιπλέον, για να διερευνήσουμε τη δυναμική εξέλιξη της ηφαιστειακής-σεισμοτεκτονικής δραστηριότητας, εκτιμήσαμε τους εντροπικούς δείκτες σκέδασης qs όπως αυτοί προκύπτουν από την μη γραμμική ανάλυση των PDFs, παρουσιάζοντας τις μεταβολές τους ως συνάρτηση του χρόνου, του χώρου (χωροχρονική μεταβολή), του τοπικού μεγέθους (ML) καθώς και της επικεντρικής απόστασης (km) πριν, κατά τη διάρκεια και μετά την περίοδο ηφαιστειακής κρίσης της καλντέρας, από το 2009 έως το 2014.The unrest period in Santorini's caldera during 2011-2012, led several studies to raise the important question of whether seismicity is associated with an impending and potential volcanic eruption or if it solely relieves the accumulated tectonic energy. In the present work, we study seismic coda waves, generated by local earthquake events prior, during and after the Santorini’s unrest period (volcanic and seismic crisis) that occurred within the caldera area. Coda waves are interpreted as scattered seismic waves generated by heterogeneities within the Earth, i.e. by faults, fractures, fissure structures, microcracks, velocity and/or density boundaries/anomalies, etc. In particular, we utilize all three components of the seismograms recorded by three seismological stations on the Santorini island and estimate the duration of the coda waves by implementing a five-step procedure that includes the signal-to-noise ratio, the STA/LTA like method, in time domain and upon analytic signal obtained after implementing Hilbert transformation, and the short time Fourier transform, using gaussian windowing as a window function. The final estimation was verified or re-estimated manually due to the existent ambient seismic noise. Because of the nature and the path complexity of the coda waves and towards achieving a unified framework for the study of the immerse geo-structural seismotectonic complexity of the Santorini volcanic complex, we use Non-Extensive Statistical Physics (NESP) to study the probability density functions (PDFs) of the increments of seismic coda waves. NESP, forms a generalization of the Boltzmann-Gibbs statistical mechanics that has been extensively used for the analysis of semi-chaotic systems that exhibit long-range interactions, memory effects and multi-fractality. The analysis and results demonstrate that the seismic coda waves increments, deviate from the Gaussian shape and their respective pdfs could adequately be described and processed by the q-Gaussian distribution. Furthermore and in order to investigate the dynamical evolution of the volcanic-tectonic activity, we estimate the qs indices derived from the PDFs of the coda wave time series increments, and present their variations as a function of time, of space (spaciotemporal variation), of local magnitude (ML) and epicentral distance (measured in km) prior, during and after the caldera unrest period from 2009 to 2014

Findings of an experimental study in a rabbit model on posterior capsule opacification after implantation of hydrophobic acrylic and hydrophilic acrylic intraocular lenses

Nikolaos Trakos1, Elli Ioachim2, Elena Tsanou2, Miltiadis Aspiotis1, Konstantinos Psilas1, Chris Kalogeropoulos11University Eye Clinic of Ioannina, Ioannina, Greece; 2Pathology Department, University of Ioannina, Ioannina, GreecePurpose: Study on cell growth on the posterior capsule after implantation of hydrophobic acrylic (Acrysof SA 60 AT) and hydrophilic acrylic (Akreos Disc) intraocular lenses (IOL) in a rabbit model and comparison of posterior capsule opacification (PCO).Methods: Phacoemulsification was performed in 22 rabbit eyes, and two different IOL types (Acrysof SA60 AT and Akreos Disc) were implanted. These IOLs had the same optic geometry (square edged) but different material and design. Central PCO (CPCO), peripheral PCO (PPCO), Sommering’s ring (SR) formation, type of growth, extension of PCO, cell type, inhibition, and fibrosis were evaluated three weeks after surgery. Histological sections of each globe were prepared to document the evaluation of PCO.Results: No statistically significant difference was observed between a hydrophobic acrylic IOL and a hydrophilic acrylic IOL in relation to the CPCO, PPCO, type of growth, extension, cell type, inhibition, and fibrosis. Statistically significant difference was observed in relation to the formation of SR with Acrysof SA 60 AT group presenting more SR than Akreos Disc group.Conclusion: PCO was not influenced by the material of the IOL or the design of the haptics of the IOLs we studied.Keywords: posterior capsule opacification, intraocular lenses, rabbit mode

Bartonella and intraocular inflammation: a series of cases and review of literature

Chris Kalogeropoulos1, Ioannis Koumpoulis1, Andreas Mentis2, Chrisavgi Pappa1, Paraskevas Zafeiropoulos1, Miltiadis Aspiotis11Department of Ophthalmology, Medical School, University of Ioannina, Greece; 2Laboratory of Medical Microbiology, Hellenic Pasteur Institute, Athens, GreecePurpose: To present various forms of uveitis and/or retinal vasculitis attributed to Bartonella infection and review the impact of this microorganism in patients with uveitis.Methods: Retrospective case series study. Review of clinical records of patients diagnosed with Bartonella henselae and Bartonella quintana intraocular inflammation from 2001 to 2010 in the Ocular Inflammation Department of the University Eye Clinic, Ioannina, Greece. Presentation of epidemiological and clinical data concerning Bartonella infection was provided by the international literature.Results: Eight patients with the diagnosis of Bartonella henselae and two patients with B. quintana intraocular inflammation were identified. Since four patients experienced bilateral involvement, the affected eyes totaled 14. The mean age was 36.6 years (range 12–62). Uveitic clinical entities that we found included intermediate uveitis in seven eyes (50%), vitritis in two eyes (14.2%), neuroretinitis in one eye (7.1%), focal retinochoroiditis in one eye (7.1%), branch retinal vein occlusion (BRVO) due to vasculitis in one eye (7.1%), disc edema with peripapillary serous retinal detachment in one eye (7.1%), and iridocyclitis in one eye (7.1%). Most of the patients (70%) did not experience systemic symptoms preceding the intraocular inflammation. Antimicrobial treatment was efficient in all cases with the exception of the case with neuroretinitis complicated by anterior ischemic optic neuropathy and tubulointerstitial nephritis.Conclusion: Intraocular involvement caused not only by B. henselae but also by B. quintana is being diagnosed with increasing frequency. A high index of suspicion is needed because the spectrum of Bartonella intraocular inflammation is very large. In our study the most common clinical entity was intermediate uveitis.Keywords: Bartonella, neuroretinitis, intermediate uveitis, retinal vascular occlusio

Etude pharmacodynamique de la plante toxique Œnanthe silaifolia

Aspiotis N., Lavrentiades G., Andréou Ch. Étude pharmacodynamique de la plante toxique Œnanthe silaifolia. In: Bulletin de l'Académie Vétérinaire de France tome 113 n°1, 1960. pp. 75-80

Graphene-based fiber polarizer with PVB-enhanced light interaction

Graphene is a two-dimensional material which, as a result of its excellent photonic properties, has been investigated for a wide range of optical applications. In this paper, we propose and fabricate a commercial grade broadband graphene-based fiber polarizer using a low loss side-polished optical fiber platform. A high index polyvinyl butyral layer is used to enhance the light-graphene interaction of the evanescent field of the core guided mode to simultaneously obtain a high extinction ratio ~37.5 dB with a low device loss ~1 dB. Characterization of the optical properties reveals that the polarizer retains low transmission losses and high extinction ratios across an extended telecoms band. The results demonstrate that side-polished fibers are a useful platform for leveraging the unique properties of low-dimensional materials in a robust and compact device geometry