Late Quaternary ecosystem and climate interactions in SW Balkans inferred from Lake Prespa sediments

The transboundary Lake Prespa and its watershed enclose a remarkable biodiversity that is protected by several national and international treaties. Situated at 849 m a.s.l., the area is characterized by a transitional climate and the closed nature of the basin controls Lake Prespa’s modern hydrology. An 18 m-long sediment sequence was retrieved from a distal location, away from stream inflow, where preliminary hydroacoustic investigations suggested undisturbed sedimentation. Consequently, the sediments were dated and analyzed using palynological, sedimentological and geochemical techniques. The age model is based on AMS and ESR dating, tephrochronology and cross correlation with the Greenland ice record (NGRIP) and suggests an age of c. 92 ka cal BP for the base of the sequence. The pollen spectra allow for the zoning of the record in three major phases of vegetation development corresponding to Marine Isotope Stages 5 to 1. The forested phases of MIS 5 and MIS 1 are dominated by thermophilous and drought-sensitive trees (e.g. Quercus, Carpinus, Fagus) suggesting higher temperatures and moisture availability during their growing season. Increased lake productivity, hypolimnion anoxia and calcite precipitation are recorded in these intervals. Continuous presence of Mediterranean frost-sensitive species (e.g. Pistacia, Phillyrea) during the Holocene implies rising temperatures in late winter and spring. Sporadic occurrence of maquis pollen in MIS 5 suggest that temperature was probably limiting their expansion. Increasing fuel availability and summer aridity most likely account for a higher microscopic charred particle concentration during the Holocene (in particular after c. 5.5 ka). However, intensifying anthropogenic activity has probably overridden climate forcing over the last c. 2 ka. Within MIS 5 and MIS 1, brief periods (centennial to millennial) of open landscape are also documented and are ascribed to colder and drier climate conditions persisting at Prespa. During MIS 3, the relatively open landscape is characterized by several deciduous trees besides Pinus. An open steppe landscape with scattered tree stands comprising mostly Pinus prevailed in MIS 4 and MIS 2. High Artemisia and Chenopodiaceae abundances point to rather cold and arid conditions at Prespa. This appears to be in agreement with low lake productivity, enhanced mixing and increased ice-cover documented for this time. However, occurrences of deciduous tree pollen throughout the Last Glacial provide evidence for the survival of several tree species in sheltered locations at Prespa or its vicinity. This study underscores the sensitivity of the Lake Prespa region to climate forcing over the Last Glacial and the Holocene. The vegetation history of the region was examined focusing on ecological processes such as immigration, competition, succession, population growth and stability. Ongoing investigations may offer further insights into the paleoenvironment and paleoclimate at Prespa. The Prespa pollen underline the potential of the region to serve as refugium over longer time scales. In spite of systematic conservation efforts over the last decades, the question of whether Prespa’s ecosystems will withstand increasing anthropogenic pressures remains open

Ελευθερία Έκφρασης και Μέσα Κοινωνικής Δικτύωσης

Με την παρούσα μελέτη θα επιχειρηθεί η σκιαγράφηση του τοπίου που διαμορφώνουν οι νέες συνθήκες ηλεκτρονικής «άνθισης» για την ελευθερία έκφρασης και η σχέση της με τα υπόλοιπα ατομικά δικαιώματα ενόψει της διάπλασης της οικουμενικής κοινωνίας της πληροφορίας και της μαζικής ψηφιακής συμμετοχικής λειτουργίας. Η προστασία του δικαιώματος στην ελεύθερη έκφραση αποτελεί σημαντική κατάκτηση των δημοκρατικών κοινωνικών μορφωμάτων και αναπόσπαστο κομμάτι της δημοκρατικής λειτουργίας. Αφού μας απασχολήσει το θέμα της νομικής κατοχύρωσης του δικαιώματος θα ασχοληθούμε με το δικαίωμα συμμετοχής του ατόμου στην κοινωνία της πληροφορίας, υπό το πρίσμα της «αλλαγής του επικοινωνιακού παραδείγματος», με την ερμηνεία των «παραδοσιακών» του δικαιωμάτων στη νέα εποχή και με την βολιδοσκόπηση της καινής ψηφιακής συμμετοχικότητας. Έπειτα, θα επιχειρηθεί η καταγραφή, η κατανόηση και η ερμηνεία των κατευθύνσεων που υιοθετήθηκαν από την Κεντρική Εξουσία, στον δυτικό κόσμο, για τη ρύθμιση της ηλεκτρονικής πραγματικότητας. Τέλος, θα προσπαθήσουμε να εστιάσουμε στον ανταγωνισμό ανάμεσα στην ελευθερία της έκφρασης και στα υπόλοιπα ατομικά δικαιώματα και θα επιχειρήσουμε να εμπεδώσουμε τον πραγματικό χώρο που καταλαμβάνει το δικαίωμα με την «παραδοσιακή» του μορφή στο πεδίο εκτύλιξης της ψηφιακής συμμετοχικής διαδικασίας.The present study is an attempt to outline the situation that is formed with the new condi-tions of the electronic “blossoming” for the freedom of speech and its relation with the rest individual rights in view of the spread of the information society and the involvement of the media industry. The right to free expression and its protection is an important achievement for society and an integral part of democracy and its operation. After dealing with the legal vesting of this specific right, we will be dealing with the right of every individual to participate in the information society, under the scope of the change that takes place in the communicative example by interpreting its “ traditional” rights in the new era. At the same time we need to keep in mind the participation in the new digital society. Moreover, attempts will be carried out to capture, comprehend and interpret the guidelines that were adopted by the Main Authority, in the western society, for the regulation of the digital reality. Finally, we will try to focus on the competitiveness between the right to freedom of speech and the rest of the individual rights. Furthermore, we will try to comprehend and under-stand the real space that the right conquers in its 'traditional' form, in the field of digital pro-cess and the participation in it.

VISION DIFFMASK: Faithful Interpretation of Vision Transformers with Differentiable Patch Masking

The lack of interpretability of the Vision Transformer may hinder its use in critical real-world applications despite its effectiveness. To overcome this issue, we propose a post-hoc interpretability method called VISION DIFFMASK, which uses the activations of the model's hidden layers to predict the relevant parts of the input that contribute to its final predictions. Our approach uses a gating mechanism to identify the minimal subset of the original input that preserves the predicted distribution over classes. We demonstrate the faithfulness of our method, by introducing a faithfulness task, and comparing it to other state-of-the-art attribution methods on CIFAR-10 and ImageNet-1K, achieving compelling results. To aid reproducibility and further extension of our work, we open source our implementation: https://github.com/AngelosNal/Vision-DiffMaskComment: Accepted in the XAI4CV Workshop at CVPR 202

In-situ TEM study of the crystallization sequence in a gold-based metallic glass

The composition Au49Ag5.5Pd2.3Cu26.9Si16.3 (at.%) is of interest as the basis for the development of gold-based bulk metallic glasses for application in jewellery. In-situ heating in transmission electron microscopy (TEM) and differential scanning calorimetry (DSC, both conventional and fast) are used to obtain a comprehensive characterization of the decomposition on heating a melt-spun glass of this composition. Linking TEM with DSC over a range of heating rates 0.083‒2000 K s‒1, allows the sample temperature in the TEM heating stage to be calibrated. On heating up to melting, the glass decomposes in up to four stages: (1) complete transformation to single-phase nanocrystalline (Au,Cu)7Si; (2) grain growth of this phase; (3) precipitation of (Pd,Ag)Si, reducing the supersaturation of silicon in the (Au,Cu)7Si matrix; (4) with the precipitate phase remaining stable, decomposition of the matrix to a mixture of (Au,Ag)8Cu2, AuCu and Cu3Au phases. At all stages, grain diameters remain sub-micrometre; some of the stable nanocrystalline microstructures may themselves be of interest for applications. The characterization of the decomposition can assist in the optimization of the glass composition to improve tarnish-resistance, while retaining adequate glass-forming ability, formability in thermoplastic processing, and resistance to crystallization. For materials in general, the close correlation of in-situ TEM and DSC results should find wide use in characterizing complex transformation sequences

Novel micro-flat springs using the superior elastic properties of metallic glass foils

A thin metallic glass foil of 100 mg mass forming a sinusoidal arc behaves as non-conventional flat micro-spring withstanding loads 105 times higher than its load. Upon a normal load applied on the top of the arc, the foil deforms elastically leading to sinusoidal wavy patterns of higher order. The lifespan of the novel spring is higher than conventional low cycle springs and can potentially be further improved by eliminating surface and edge preparation induced defects. This unique behavior of metallic glass foils has the potential to revolutionize the field of springs and can be exploited for numerous applications