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Long-range ordering is typically associated with a decrease in entropy. Yet, it can also be driven by increasing entropy in certain special cases. We demonstrate that artificial spin ice arrays of single-domain nanomagnets can be designed to produce entropy-driven order. We focus on the tetris artificial spin ice structure, a highly frustrated array geometry with a zero-point Pauli entropy, which is formed by selectively creating regular vacancies on the canonical square ice lattice. We probe thermally active tetris artificial spin ice both experimentally and through simulations, measuring the magnetic moments of the individual nanomagnets. We find two-dimensional magnetic ordering in one subset of these moments, which we demonstrate to be induced by disorder (i.e., increased entropy) in another subset of the moments. In contrast with other entropy-driven systems, the discrete degrees of freedom in tetris artificial spin ice are binary and are both designable and directly observable at the microscale, and the entropy of the system is precisely calculable in simulations. This example, in which the system's interactions and ground state entropy are well-defined, expands the experimental landscape for the study of entropy-driven ordering., Comment: 53 pages, 19 figures (including Supplementary Information)

This paper illustrates the effectiveness of the Mellin-transform (MT) method for the exact calculation of certain one-dimensional definite integrals occurring in studies of wireless communications systems. The MT method, though it often requires laborious calculations, is a straightforward and extremely powerful technique for the closed-form evaluation of definite integrals. Only basic information is provided with regard to the MT and the closely related class of Mellin–Barnes (MB) integrals. On this basis, the MT method is applied to several examples of integrals occurring in studies of fading channels and wireless transmission systems. Closed-form expressions are obtained, which are either new or provided without proof in the literature. The new formulas are suitable for numerical evaluation.

This study deals with the investigation of old varnishes from six paintings belonging to the collection of the “Teloglion Foundation of Arts”, Aristotle University of Thessaloniki in Greece employing three complementary analytical techniques. The purpose of this research was to identify the origin of the protective layers of the varnishes with the ultimate goal of their safe removal during their treatment. To identify the components of the varnishes, sampling was carried out in both a mechanical and chemical way from selected areas of all the works of art. The samples were firstly studied with Fourier-Transform Infrared Spectroscopy (FT-IR), secondly with Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC–MS), and finally with Liquid Chromatography–Orbitrap High-Resolution Mass Spectrometry (LC–Orbitrap HRMS). The application of these methods led not only to the verification of the compounds of the varnishes, but also to the presence of specific fatty acids included in the drying oils, as well as diterpene and triterpene resins. FT-IR spectra were very similar to those corresponding to natural resins, while Py-GC–MS evidenced the fatty acids profile in drying oils as well as the presence of dammarane skeleton among others. The main findings from LC–Orbitrap MS/MS included drying and essential oils, mastic, and dammar. Based on the obtained results, a solubility study of varnishes was also performed. The appropriate mixture of solvents for the coating varnishes removal was investigated with the aid of the Teas solubility triangle and the most suitable solvent mixture for the proper restoration was proposed. A conservation effort for one painting was carried out successfully, confirming the applicability of the method.

The aim of this study was to investigate platelet function in patients with thalassaemia and to detect any relation to chelation treatment (deferasirox or deferiprone/deferiprone plus desferioxamine). Thirty-three transfusion-dependent patients with thalassaemia were included. The investigation consisted of aggregation testing of platelet-rich plasma by light transmission aggregometry (LTA) with the use of 5 agonists as well as the global test of haemostasis by means of the PFA-100 platelet function analyser. In 66.67% of the patients, there was reduced LTA to at least one agonist and in 18.18% there was reduced LTA to two or more agonists. The PFA-100 test was prolonged in 60.6% of the cases. An abnormal LTA and a prolonged PFA-100 time were recorded in 33.3% of the patients and 27.4% had a normal aggregation and PFA-100 test. No correlation between chelation regimen and either LTA or PFA-100 test was found. The abnormal LTA can be explained either by the release of ADP from the haemolysed red blood cells, which leads to defective platelet aggregation, or by the presence of two platelet populations. An in vitro effect without an in vivo impact could be an alternative explanation. In patients with thalassaemia, the reduced LTA and the prolonged PFA-100 closure time could be an in vitro effect and has a close correlation to the bleeding phenotype of each patient.

Περιέχει το πλήρες κείμενο Σκοπός της επικείμενης εργασίας είναι η δημιουργία ενός συστήματος αξιολόγησης βιβλιοθηκών, το οποίο χρησιμοποιείται με σκοπό τη μέτρηση/κατάταξη της αποδοτικότητας των λειτουργιών μιας βιβλιοθήκης. Οι παρακάτω μετρήσεις έγιναν με βάση τους καθιερωμένους δείκτες της ΜΟΠΑΒ. Καταλήξαμε στους εν λόγω δείκτες, τους οποίους θα εξετάσουμε και στους οποίους θα βασίσουμε την έρευνα λόγω των χαρακτηριστικών που παρουσιάζουν. Αρχικά, πρόκειται για τους πιο αντιπροσω- πευτικούς δείκτες για την αξιολόγηση μιας βιβλιοθήκης, καθώς οι δείκτες αυτοί αφορούν όλα τα είδη των βιβλιοθηκών και όχι μόνο τις ειδικές ή κάποιο συγκεκριμένο είδος. Πέρα από τη συχνότητα με την οποία τους συναντάμε, σημαντικός λόγος για την επιλογή τους ήταν πως αφορούν δείκτες υπηρεσιών που σχεδόν όλες οι βιβλιοθήκες έχουν· επίσης, αφορούν τις δύο από τις τρεις κύριες λειτουργίες μιας βιβλιοθήκης (πρόσκτηση και δανεισμό) και επιπλέον είναι ευκατανόητοι και εύκολα επε- ξεργάσιμοι για την εξαγωγή αποτελεσμάτων. Τα αποτελέσματα από την εκάστοτε επεξεργασία και κρίση είναι έγκυρα και αξι- όλογα, ενώ αυτονόητο είναι ότι δεν υπάρχει κόστος για την εξαγωγή τους και δεν απαιτείται κάποιο συγκεκριμένο εργαλείο. Τα κριτήρια είναι καταρχήν υποκειμενικά, αλλά η ανάλυση και η αξιολόγηση γίνεται με αντικειμενικότητα. Για τη δημιουργία του συστήματος αξιολόγησης βιβλιοθηκών βασιστήκαμε στη μάθηση με επίβλεψη με τη βοήθεια ενός νευρωνικού δικτύου.

The broad adoption of Web 2.0 tools has signalled a new era of “Medicine 2.0” in the field of medical informatics. The support for collaboration within online communities and the sharing of information in social networks offers the opportunity for new communication channels among patients, medical experts, and researchers. This paper introduces MORMED, a novel multilingual social networking and content management platform that exemplifies the Medicine 2.0 paradigm, and aims to achieve knowledge commonality by promoting sociality, while also transcending language barriers through automated translation. The MORMED platform will be piloted in a community interested in the treatment of rare diseases (Lupus or Antiphospholipid Syndrome).

When is it appropriate to discuss the divergence of organizational and technological realms and based on which assumptions? Could the social and technical disconnection be merely a constructed phenomenon, and if so, what does design thinking has to offer towards the creation of aligned organizational and technological views? Drawing from these questions this paper argues that the two notions of organization and technology are both human artifacts with an intertwined and unfolding ontology. We base our argument inspired by i) structuration theory according to which organizational structures and technologies are mutually constituted and co-evolving elements, and, ii) a conceptualization of organizations and technologies as ‘epistemic objects’ with a lack in completeness of being. We finally discuss design thinking principles as a basis for an integrated reflection of the two notions hopping to invoke creative and constructive dialogue among communities of technologists, managers and academics alike.

Personal knowledge management has been studied from various angles, one of which is the Semantic Web. Ontologies, the primary knowledge representation tool for the Semantic Web, can play a significant role in semantically managing personal knowledge. The scope of this paper focuses on addressing the issue of effective personal knowledge management, by proposing an ontology for modelling the domain of biographical events. The proposed ontology also undergoes a thorough evaluation, based on specific criteria presented in the literature.

Οι εφαρμογές συναίσθησης (awareness applications) αποτελούν συστήματα ενίσχυσης της αντίληψης της παρουσίας (presence) και εντάσσονται στην ευρύτερη κατηγορία των συστημάτων υποστήριξης της επικοινωνίας με τη διαμεσολάβηση υπολογιστών (computer mediated communication systems). Μια πληθώρα τέτοιων εφαρμογών – μικρών και εξειδικευμένων ακόμη – έχει αναπτυχθεί τα τελευταία χρόνια (π.χ. MSN, Facebook), ενώ αναμένεται η ευρύτερη διάδοσή τους ως αποτέλεσμα της ανάπτυξης των κινητών επικοινωνιών. Η παρούσα διπλωματική εργασία βασίζεται στην πλατφόρμα ανάπτυξης εφαρμογών συναίσθησης ASTRA. Το συγκριτικό πλεονέκτημα της πλατφόρμας απέναντι στις υπάρχουσες εφαρμογές είναι ότι είναι γενικευμένη και συνεπώς μπορεί να οδηγήσει στην ανάπτυξη πλήθους εφαρμογών με σχετικά εύκολο τρόπο, δίνοντας τεράστια ώθηση στην ευρύτερη ανάπτυξη του πεδίου. Η εργασία αποσκοπεί στην δημιουργία ενός πλαισίου αξιολόγησης (evaluation framework) εφαρμογών συναίσθησης, το οποίο θα βασίζεται κυρίως στο πρότυπο ISO 9126. Για το σκοπό αυτό θα αναλυθεί το εν λόγω πρότυπο και θα εντοπιστούν οι ιδιαίτερες διαστάσεις των συστημάτων συναίσθησης (τα οποία θα αναλυθούν ως εφαρμογές διαδικτύου). Στη συνέχεια θα ομαδοποιηθούν τα χαρακτηριστικά τους και θα ενταχθούν στα τέσσερα στοιχεία εξωτερικής ποιότητας που προβλέπει το πρότυπο. Ως πεδίο εφαρμογής του πλαισίου θα χρησιμοποιηθεί η πλατφόρμα ASTRA, η οποία θα αξιολογηθεί με βάση αυτό. Για το σκοπό της εργασίας θα αναπτυχθούν και ορισμένες εφαρμογές συναίσθησης με τη χρήση της πλατφόρμας. This thesis presents a quality evaluation framework for awareness systems. These are Computer Mediated Communication (CMC) systems, which support people’s needs to communicate and enhance their sense of presence. In general, quality is defined by the extent to which the software meets user needs and requirements. Our framework is based on the ISO9126 standard, which includes two quality dimensions, external and internal, and defines a set of quality criteria for each. We have chosen to adopt the end-user standpoint in evaluating awareness systems, thus we model only the four criteria groups of external quality, that is, functionality, usability, reliability and efficiency. Firstly, we present a brief introduction to software quality and the ISO9126 standard. Then, we present presence and awareness systems, and discuss their emergence and the needs they serve. We continue with a broad survey of presence and awareness systems and social software. For each of the surveyed systems (the list includes Facebook, MSN, Twitter, YouTube, LinkedIn et al), we present an extensive list of features, which support user/community management and application management. A comparative table summarizes the features of the systems surveyed. Based on this discussion, we develop the proposed evaluation framework, by listing detailed criteria for each of the four groups of external quality, according to ISO9126. For each group, we list two tables of criteria, one for community management evaluation and one for application evaluation. The criteria are sub-grouped into presentation, navigation, escalation, content, applications, communication, awareness, and connectedness. Each table is followed by a brief explanation of the criteria it contains and the range of values they assume. Then we present in detail ASTRA, the first pervasive CMC system that was designed and developed in order to enhance presence without requiring users to use a computer to join. ASTRA applies a pervasive computing interface on top of a social computing system, which supports community and awareness application management. The focus-nimbus model is used to describe the awareness framework and a novel connectedness theory is validated with the system. Finally, we evaluate and classify the presence and awareness systems, including ASTRA, according to the proposed evaluation framework.