AC and DC conductivity correlation: The coefficient of Barton--Nakajima--Namikawa relation

It has been some time since an empirical relation, which correlates DC with AC conductivity and contains a loosely defined coefficient thought to be of order one, was introduced by Barton, Nakajima and Namikawa. In this work, we derived this relation assuming that the conductive response consists of a superposition of DC conductivity and an AC conductivity term which materialized through a Havriliak--Negami dielectric function. The coefficient was found to depend on the Havriliak--Negami shape parameters as well as on the ratio of two characteristic time scales of ions motion which are related to ionic polarization mechanism and the onset of AC conductivity. The results are discussed in relation to other relevant publications and they also applied to a polymeric material. Both, theoretical predictions and experimental evaluations of the BNN coefficient are in an excellent agreement, while this coefficient shows a gradual reduction as the temperature increases.Comment: 15 pages plain latex2e, 5 eps figures (new figures added). In this revised version the manuscript has been rewritten extensively due to motivational comments and suggestions made by the referee. Accepted for publication by the Journal of Non--Crystalline Solid

Bacterial resistance to antimicrobial agents and its impact on veterinary and human medicine

Background Antimicrobial resistance has become a major challenge in veterinary medicine, particularly in the context of bacterial pathogens that play a role in both humans and animals. Objectives This review serves as an update on acquired resistance mechanisms in bacterial pathogens of human and animal origin, including examples of transfer of resistant pathogens between hosts and of resistance genes between bacteria. Results Acquired resistance is based on resistance-mediating mutations or on mobile resistance genes. Although mutations are transferred vertically, mobile resistance genes are also transferred horizontally (by transformation, transduction or conjugation/mobilization), contributing to the dissemination of resistance. Mobile genes specifying any of the three major resistance mechanisms – enzymatic inactivation, reduced intracellular accumulation or modification of the cellular target sites – have been found in a variety of bacteria that may be isolated from animals. Such resistance genes are associated with plasmids, transposons, gene cassettes, integrative and conjugative elements or other mobile elements. Bacteria, including zoonotic pathogens, can be exchanged between animals and humans mainly via direct contact, but also via dust, aerosols or foods. Proof of the direction of transfer of resistant bacteria can be difficult and depends on the location of resistance genes or mutations in the chromosomal DNA or on a mobile element. Conclusion The wide variety in resistance and resistance transfer mechanisms will continue to ensure the success of bacterial pathogens in the future. Our strategies to counteract resistance and preserve the efficacy of antimicrobial agents need to be equally diverse and resourceful. This article is based on a State of the Art presentation at the 8th World Congress of Veterinary Dermatology held May 2016 in Bordeaux, France

Το ταφικό έθιμο της ανέγερσης τύμβου κατα μήκος της Ιονίας και Αδριατικής ακτής ως πολιτιστικό και κοινωνικό φαινόμενο

This article deals with the two-folded role of the burial custom of tumulus along the Adriatic and Ionian Arc, both as an impressive architectural construction that excels in the surrounding area, as well as a symbolic place of collective memory for the local communities. Initially, the main architectural features –the central burial, the soil and the enclosure– are presented, which, with varied local peculiarities, determine the emergence of the tumulus almost simultaneously in these regions and its evolution in the course of the 3rd and 2nd millennia BC. Furthermore, the article is focused on the chronological and geographical distribution of the tumulus custom starting from the northern Adriatic and ending in the southern part of the Ionian Sea with the scope of unfolding local similarities and differences. The social role of the tumulus as a labour-intensive, enduring and highly visible ancestral monument – signal (sema), is then addressed, via both its topographical correlation to its settlement and the surrounding landscape, and via the ceremonial acts performed in several of them in the study area. Finally, through the choice of selected groups of finds and the adoption of common burial practices, the cultural relations of these regions and the special bond developed between them during the Bronze Age are emerging

Biology and genomics of an historic therapeutic Escherichia coli bacteriophage collection

We have performed microbiological and genomic characterization of an historic collection of nine bacteriophages, specifically infecting a K1 E. coli O18:K1:H7 ColV+ strain. These phages were isolated from sewage and tested for their efficacy in vivo for the treatment of systemic E. coli infection in a mouse infection model by Smith and Huggins (1982). The aim of the study was to identify common microbiological and genomic characteristics, which co-relate to the performance of these phages in in vivo study. These features will allow an informed selection of phages for use as therapeutic agents. Transmission electron microscopy showed that six of the nine phages were Podoviridae and the remaining three were Siphoviridae. The four best performing phages in vivo belonged to the Podoviridae family. In vitro, these phages exhibited very short latent and rise periods in our study. In agreement with their microbiological profiles, characterization by genome sequencing showed that all six podoviruses belong to the Autographivirinae subfamily. Of these, four were isolates of the same species (99% identity), whereas two had divergent genomes compared to other podoviruses. The Siphoviridae phages, which were moderate to poor performers in vivo, exhibited longer latent and rise periods in vitro. Two of the three siphoviruses were closely related to each other (99% identity), but all can be associated with the Guernseyvirinae subfamily. Genome sequence comparison of both types of phages showed that a gene encoding for DNA-dependent RNA polymerase was only present in phages with faster replication cycle, which may account for their better performance in vivo. These data define a combination of microbiological, genomic and in vivo characteristics which allow a more rational evaluation of the original in vivo data and pave the way for the selection of phages for future phage therapy trails

Modeling Reader's Emotional State Response on Document's Typographic Elements

We present the results of an experimental study towards modeling the reader's emotional state variations induced by the typographic elements in electronic documents. Based on the dimensional theory of emotions we investigate how typographic elements, like font style (bold, italics, bold-italics) and font (type, size, color and background color), affect the reader's emotional states, namely, Pleasure, Arousal, and Dominance (PAD). An experimental procedure was implemented conforming to International Affective Picture System guidelines and incorporating the Self-Assessment Manikin test. Thirty students participated in the experiment. The stimulus was a short paragraph of text for which any content, emotion, and/or domain dependent information was excluded. The Analysis of Variance revealed the dependency of (a) all the three emotional dimensions on font size and font/background color combinations and (b) the Pleasure dimension on font type and font style. We introduce a set of mapping rules showing how PAD vary on the discrete values of font style and font type elements. Moreover, we introduce a set of equations describing the PAD dimensions' dependency on font size. This novel model can contribute to the automated reader's emotional state extraction in order, for example, to enhance the acoustic rendition of the documents, utilizing text-to-speech synthesis

Emerging Evidence for Neolithic Ithaca

The article presents new evidence for the Neolithic habitation on Ithaca, consisting of ceramic and stone finds, recognised among material from the University of Ioannina excavations at the site of Agios Athanasios-School of Homer in the northwest part of Ithaca, Greece. The new Neolithic site is considered within the wider cultural context of the Ionian Islands, in the late 5th/4th millennium BC. Our current knowledge suggests a permanent Neolithic occupation at the site, as opposed to seasonal occupation or to a special purpose occupation. The Neolithic people at the School of Homer may have been part of a dynamic network of Late/Final Neolithic installations in Western Greece, engaging themselves in inter-regional communal connections along the routes of the most ancient seafaring in the Ionian Sea