Three--body Correlation Effects on the Spin Dynamics of Double--Exchange Ferromagnets

We present a variational calculation of the spin wave excitation spectrum of double--exchange ferromagnets in different dimensions. Our theory recovers the Random Phase approximation and 1/S expansion results as limiting cases and can be used to study the intermediate exchange coupling and electron concentration regime relevant to the manganites. In particular, we treat exactly the long range three--body correlations between a Fermi sea electron--hole pair and a magnon excitation and show that they strongly affect the spin dynamics in the parameter range relevant to experiments in the manganites. The manifestations of these correlations are many-fold. We demonstrate that they significantly change the ferromagnetic phase boundary. In addition to a decrease in the magnon stiffness, we obtain an instability of the ferromagnetic state against spin wave excitations close to the Brillouin zone boundary.Within a range of intermediate concentrations, we find a strong softening of the spin wave dispersion as compared to the Heisenberg ferromagnet with the same stiffness, which changes into hardening for other concentrations. We discuss the relevance of these results to experiments in colossal magnetoresistance ferromagnets.Comment: 14 pages, 11 figures, published in Phys. Rev. B (1 figure added, references added

Phylogenomics investigation of sparids (Teleostei: Spariformes) using high-quality proteomes highlights the importance of taxon sampling

Sparidae (Teleostei: Spariformes) are a family of fish constituted by approximately 150 species with high popularity and commercial value, such as porgies and seabreams. Although the phylogeny of this family has been investigated multiple times, its position among other teleost groups remains ambiguous. Most studies have used a single or few genes to decipher the phylogenetic relationships of sparids. Here, we conducted a thorough phylogenomic analysis using five recently available Sparidae gene-sets and 26 high-quality, genome-predicted teleost proteomes. Our analysis suggested that Tetraodontiformes (puffer fish, sunfish) are the closest relatives to sparids than all other groups used. By analytically comparing this result to our own previous contradicting finding, we show that this discordance is not due to different orthology assignment algorithms; on the contrary, we prove that it is caused by the increased taxon sampling of the present study, outlining the great importance of this aspect in phylogenomic analyses in general

An evolutionary perspective on marine invasions

Species distributions are rapidly changing as human globalization increasingly moves organisms to novel environments. In marine systems, species introductions are the result of a number of anthropogenic mechanisms, notably shipping, aquaculture/mariculture, the pet and bait trades, and the creation of canals. Marine invasions are a global threat to human and non�human populations alike and are often listed as one of the top conservation concerns worldwide, having ecological, evolutionary, and social ramifications. Evolutionary investigations of marine invasions can provide crucial insight into an introduced species’ potential impacts in its new range, including: physiological adaptation and behavioral changes to exploit new environments; changes in resident populations, community interactions, and ecosystems; and severe reductions in genetic diversity that may limit evolutionary potential in the introduced range. This special issue focuses on current research advances in the evolutionary biology of marine invasions and can be broadly classified into a few major avenues of research: the evolutionary history of invasive populations, post�invasion reproductive changes, and the role of evolution in parasite introductions. Together, they demonstrate the value of investigating marine invasions from an evolutionary perspective, with benefits to both fundamental and applied evolutionary biology at local and broad scales

Περιεγχειρητική διαχείριση ασθενών που υποβάλλονται σε οισοφαγεκτομή για νεοπλασία. Ανασκόπηση βιβλιογραφίας.

Η περιεγχειρητική διαχείριση παίζει καθοριστικό ρόλο στη βελτιστοποίηση των αποτελεσμάτων για ασθενείς που υποβάλλονται σε οισοφαγεκτομή για νεοπλασία. Αυτή η ανασκόπηση εστιάζει στις διάφορες πτυχές της περιεγχειρητικής φροντίδας, συμπεριλαμβανομένης της προεγχειρητικής αξιολόγησης, των διεγχειρητικών στρατηγικών και της μετεγχειρητικής διαχείρισης, με στόχο τη μείωση των επιπλοκών και τη βελτίωση της έκβασης των ασθενών. Οι βασικοί τομείς που εξετάζονται περιλαμβάνουν την αναισθησιολογική διαχείριση, την αναπλήρωση υγρών, τον έλεγχο του πόνου, τη διατροφική υποστήριξη, την πρώιμη εντερική σίτιση, την πνευμονική υγιεινή, την πρόληψη μετεγχειρητικών επιπλοκών και την πρώιμη κινητοποίηση του ασθενούς. Τονίζεται η σημασία μιας πολυεπιστημονικής προσέγγισης και εξατομικευμένης φροντίδας για την αντιμετώπιση των ειδικών αναγκών και προκλήσεων που σχετίζονται με τη χειρουργική νεοπλασίας του οισοφάγου.Perioperative management plays a crucial role in optimizing outcomes for patients undergoing esophagectomy for neoplasia. This review focuses on the various aspects of perioperative care, including preoperative evaluation, intraoperative strategies, and postoperative management, aimed at reducing complications and improving patient outcomes. Key areas discussed include anesthetic management, fluid resuscitation, pain control, nutritional support, early enteral feeding, pulmonary hygiene, prevention of postoperative complications, and early mobilization of the patient. The importance of a multidisciplinary approach and individualized care is emphasized to address the specific needs and challenges associated with esophageal neoplasia surgery

Η Σεισμο-Ηφαιστειακή Κρίση της Σαντορίνης 2011-2012. Ο ρόλος της Ειδικής Επιστημονικής Επιτροπής Παρακολούθησης Ηφαιστείου Σαντορίνης

Τον Ιανουάριο του 2011, άρχισε να παρατηρείται ασυνήθιστη αύξηση στη σεισμική δραστηριότητα του ηφαιστείου της Σαντορίνης. Συγκεκριμένα κατεγράφησαν σημαντικές μεταβολές στην παραμόρφωση του αναγλύφου, στη θερμοκρασία και στο χημισμό των θερμών ρευστών και των εδαφικών αερίων ενώ πλήθος σεισμών μικρού μεγέθους αναστάτωναν την τοπική κοινωνία. Τον Ιανουάριο του 2012, πραγματοποιήθηκε σύσκεψη στον Ο.Α.Σ.Π. (Οργανισμός Αντισεισμικού Σχεδιασμού και Προστασίας) στην οποία παρουσιάστηκαν τα μέχρι τότε αποτελέσματα. Πολλά ήταν τα επιστημονικά θέματα που έπρεπε να ληφθούν υπόψη σχετικά με την παρακολούθηση του ηφαιστείου. Επιτακτική όμως ήταν και η ανάγκη για το συντονισμό των δράσεων για την παρακολούθηση και τη σύσταση ανάλογης Επιτροπής. Για το λόγο αυτό, το Φεβρουάριο του 2012, με απόφαση του τότε Υφυπουργού Υποδομών, Μεταφορών και Δικτύων κ. Ι. Μαγκριώτη, συγκροτήθηκε η 18μελής Ειδική Επιστημονική Επιτροπή Παρακολούθησης Ηφαιστείου Σαντορίνης (Ε.Ε.Ε.Π.Η.Σ.) με διετή θητεία. Τα μέλη της ήταν καταξιωμένοι επιστήμονες γεωλόγοι, ηφαιστειολόγοι, σεισμολόγοι, μηχανικοί από φορείς όπως το Υπουργείο Υποδομών, Μεταφορών και Δικτύων, τον Οργανισμό Αντισεισμικού Σχεδιασμού και Προστασίας, το Γεωδυναμικό Ινστιτούτο, το Ινστιτούτο Γεωλογικών Μεταλλευτικών Ερευνών, το Ελληνικό Κέντρο Θαλασσίων Ερευνών, την Πολιτική Προστασία καθώς και από τον Πανεπιστημιακό χώρο (Εθνικό Καποδιστριακό Πανεπιστήμιο Αθηνών, Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης, Πανεπιστήμιο Πατρών, Εθνικό Μετσόβιο Πολυτεχνείο). Ο ρόλος της επιτροπής ήταν η διαρκής παρακολούθηση και αξιολόγηση των επιστημονικών δεδομένων του ηφαιστείου, η γνωμοδότηση και η εισήγηση προς τον Ο.Α.Σ.Π. μέτρων προστασίας κατά περίπτωση. Επίσης η λήψη μέτρων και απαιτούμενων ενεργειών που σχετίζονται με την εξασφάλιση της επάρκειας και της συνεχούς και απρόσκοπτης λειτουργίας του επιστημονικού εξοπλισμού και των οργάνων παρακολούθησης. Με αυτόν τον τρόπο θα διασφαλίζονταν η συλλογή των καταγραφών και στοιχείων που κρίνονταν απαραίτητα για την παρακολούθηση της δραστηριότητας του ηφαιστείου. Για την καλύτερη λειτουργία της, συστάθηκαν τέσσερις Υποεπιτροπές με τους αντίστοιχους συντονιστές τους: α) Η Υποεπιτροπή Σεισμολογίας, β) Παρακολούθησης Παραμορφώσεων, γ) Παρακολούθησης των Φυσικοχημικών μεταβολών και δ) της Πολιτικής Προστασίας. Κατατέθηκε αίτημα χρηματοδότησης προς το Υπουργείο Υποδομών, Μεταφορών και Δικτύων για την υποστήριξη του έργου της Ε.Ε.Ε.Π.Η.Σ., η οποία χρηματοδοτήθηκε με το ποσό των 156.000 Ευρώ. Αυτά κατανεμήθηκαν για την περιορισμένη προμήθεια και εγκατάσταση νέου εξοπλισμού, επισκευές και συντηρήσεις υπάρχοντος εξοπλισμού και πραγματοποίηση μετρήσεων πεδίου. Τους πρώτους κιόλας μήνες, έγινε πρόσκληση σε 30 καταξιωμένους ξένους επιστήμονες για συνεργασία όσον αφορά στη συλλογή στοιχείων μετρήσεων, εξειδικευμένου εξοπλισμού, παροχή τεχνογνωσίας και συμβουλευτικές οδηγίες για τη διαχείριση του ηφαιστειακού κινδύνου. Οι περισσότεροι από αυτούς, αποδέχτηκαν την πρόσκληση με μεγάλη προθυμία χωρίς χρηματοδότηση. Στο πλαίσιο αυτό, η τρίτη σύσκεψη της Ε.Ε.Ε.Π.Η.Σ. πραγματοποιήθηκε στη Σαντορίνη, όπου τα μέλη της Ε.Ε.Ε.Π.Η.Σ. συναντήθηκαν με τους ξένους επιστήμονες και αντάλλαξαν απόψεις, κατά τη διάρκεια του workshop MeMoVolc. Στο διάστημα της θητείας της Επιτροπής, πραγματοποιήθηκαν δέκα συνεδριάσεις, στις οποίες συζητήθηκαν οι επιστημονικές εξελίξεις και λήφθηκαν σοβαρές αποφάσεις για τις περαιτέρω ενέργειες τόσο της Επιτροπής όσο και της Πολιτείας. Η Επιτροπή ενημέρωνε με εμπιστευτικά μηνύματα το Γενικό Γραμματέα Πολιτικής Προστασίας. Τον Ιούνιο του 2013, συντάχθηκε από τα μέλη της Υποεπιτροπής Πολιτικής Προστασίας, η τελική Έκθεση με αντικείμενο τη διαχείριση του ηφαιστειακού κινδύνου με τίτλο: «Σενάρια επαναδραστηριοποίησης και εκτίμηση ηφαιστειακού κινδύνου του ηφαιστειακού συμπλέγματος Σαντορίνης» η οποία υποβλήθηκε στη Γενική Γραμματεία Πολιτικής Προστασίας. Σύμφωνα με αυτήν, δύο ήταν τα σενάρια επαναδραστηριοποίησης. Το ακραίο σενάριο με μία υπο-πλινιακού τύπου έκρηξη και το πιθανότερο με μία ενδοκαλδερική επαναδραστηριοποίηση των ηφαιστειακών κέντρων των Καμένων. Αναλύθηκαν όλοι οι κίνδυνοι, τα πρόδρομα φαινόμενα, οι επηρεαζόμενες περιοχές, οι πιθανές επιπτώσεις στον πληθυσμό, τις υποδομές καθώς και τα προτεινόμενα μέτρα μετριασμού των επιπτώσεων.Since 1950, The Santorini volcano was in a state of rest. In January 2011 and for the first half of the 2012, the scientists, according to the permanent installed monitoring networks and a big number of campaign measurements, observed an increase of the volcanic activity. Significant changes in the deformation of the texture, temperature and chemistry of the hot fluid and soil gases were recorded while numerous small earthquakes upset the local community. Volcanotectonic earthquakes of small magnitude (M=3.6) were often along the Kameni line, of 6 km length, in a depth of 1-6 km for 15 months. The GPS networks as well as the radar interferometry, revealed a 10 cm uplift of the Kameni islands. The source of the inflation (Mogi source) was found beneath the northern caldera basin, in the depth of 3-6 km and the increase of the volume was estimated of about 10-20 million m3. During the unrest, there were small increases in the fluxes of H2 and CO2 derived from the mantle. According to the International Alert-Notification System for Volcanic Activity, the alert for Santorini volcano was the initial stage of the advisory phase, in the yellow color. The spring of 2012, the monitoring networks have indicated that the volcano had returned to the previous state of activity. In January 2012, a meeting was held in the Earthquake Planning and Protection Organization (E.P.P.O.) which featured the hitherto results. Many were the scientific issues that had to be taken into account on the monitoring of the volcano, but the need for coordination of actions to monitor and provide appropriate measures was urgent. So, in February 2012, by decision of the Minister of Infrastructures, Transport and Networks, a National Scientific Committee for Monitoring Santorini Volcano (N.S.C.M.S.V.) was established, with 18 members for two years term. The members were distinguished scientists, geologists, engineers, seismologists, volcanologists, all from Scientific Organizations, Ministries, Universities and Civil Protection. The role of the Committee was the continuous monitoring and evaluation of scientific volcanic data, the opinion and recommendation to the E.P.P.O. of appropriate protective measures, any other measures required and operations related to ensuring the adequacy and continuous operation of scientific equipment and monitoring instruments, so as to ensure the collection of records and information that are necessary to monitor the volcano's activity. For the best operation, 4 subcommittees were set up with their coordinators concerning the Seismology, the Deformation Monitoring, the Physicochemical changes and the Civil Protection. Each of them, took a budget and presented an output at the end. During the mandate of the Commission, ten meetings took place, in the offices of the Earthquake Planning and Protection Organization, with full written records, in which scientific developments were discussed and important decisions were taken for further actions of both the Commission and the State. Some of the decisions that were taken was the collaboration with other Institutions and scientists, Greek or Foreigner (e.g.Georgia Tech, N.E.R.C.), in terms of data, the development of a GIS programme with seismic and geodetic data in the web site of the Earthquake Planning and Protection Organization, funding of the actions, frequent updates to the General Secretariat of Civil Protection and the Minister of Infrastructures with confidential reports, composition of volcanic hazard maps and a final report including the hazard risks and the scenarios of reactivation. Funding request to the Ministry of Infrastructure, Transport and Networks was made to support the plans of the N.S.C.M.S.V., which was finally funded with the amount of 156,000 Euros. This amount was allocated to the limited supply and installation of new equipment, repairs and maintenance of existing equipment and making field measurements. The Universities of Athens, Thessaloniki, Patra, the Geodynamic Institute, the National Technical School of Athens, the Earthquake Planning and Protection Organization, the Institute of the Study and Monitoring of the Santorini Volcano, the Institute of Geological and Mineral Exploration, had offered their equipment for the monitoring of the activity. A network of 21 seismological stations,12 GPS stations, tide gauge and other geochemical instruments, were in the disposal of the Committee. In the first months, 30 renowned foreign scientists from Italy, France, England, Iceland, and United States of America were invited for cooperation on available data measurements, specialized equipment, providing expertise and advice for the management of volcanic risk. Most of them accepted the invitation with alacrity inexpensively. They were already in collaboration with the Greek scientists and had installed their own equipment. In this context, the third meeting of N.S.C.M.S.V. took place in Santorini, on March 27, 2012, where the N.S.C.M.S.V. members met some of the foreign scientists and exchanged views, during the MeMoVolc workshop. In June 2013, the members of the Subcommittee for Civil Protection, had fulfilled the final report about the volcanic risk management and entitled "Scenarios reactivation and volcanic hazard assessment of the Sanorini Volcanic Complex” which was submitted to the General Secretariat for Civil Protection. According to that, there are two scenarios of reactivation, based on the past behavior of the volcano and available research results. The extreme scenario with a sub-plinian type of explosion and most likely an inter-caldera reactivation of volcanic centers of Kameni islands. They analyzed all the risks, the precursor phenomena, the affected areas, the potential impacts on people, infrastructures and the recommended mitigation measures. In addition, two volcanic hazard maps of Santorini was given to the Civil Protection for each of these scenarios, given into account the volcanic, seismic and the geotechnical hazards of Santorini Volcanic Complex. Therefore, the Civil Protection would make all the plans, take all the measures and the actions for the safety of the inhabitants, the tourists and the infrastructures and to preserve the balance in the social and economical life in the region. On this basis, the Greek Civil Protection is about to establish an Emergency Plan for volcanic risk with the code name “Xenokratis-Volcanoes, Santorini” in the near future. The Greek Scientific Community is now more experienced in volcanic risk management. Despite the fact that the financial support was never not enough, all the members of the Committee had worked hard, with seriousness, prοfessionalism, unity even when scientific different aspects were present. The Committee had successfully fulflilled its purpose for the benefit of the State and set the basis for an effective volcanic management in the future

Muscle and liver transcriptome characterization and genetic marker discovery in the farmed meagre, Argyrosomus regius

Meagre (Argyrosomus regius), a teleost fish of the family Sciaenidae, is part of a group of marine fish species considered new for Mediterranean aquaculture representing the larger fish cultured in the region. Meagre aquaculture started ~ 25 years ago in West Mediterranean, and the supply of juveniles has been dominated by few hatcheries. This fact has raised concerns on possible inbreeding, urging the need for genetic information on the species and for an assessment of the polymorphisms found in the genome. To that end we characterized the muscle and liver transcriptome of a pool of meagre individuals, from different families and phenotypic size, to obtain a backbone that can support future studies regarding physiology, immunology and genetics of the species. The assembled transcripts were assigned to a wide range of biological processes including growth, reproduction, metabolism, development, stress and behavior. Then, to infer its genetic diversity and provide a catalogue of markers for future use, we scanned the reconstructed transcripts for polymorphic genetic markers. Our search revealed a total of 42,933 high quality SNP and 20,581 STR markers. We found a relatively low rate of polymorphism in the transcriptome that may indicate that inbreeding has taken place. This study has led to a catalogue of genetic markers at the expressed part of the genome and has set the ground for understanding growth and other traits of interest in meagre.info:eu-repo/semantics/acceptedVersio

The sex-specific transcriptome of the hermaphrodite sparid sharpsnout seabream (Diplodus puntazzo)

Background: Teleosts are characterized by a remarkable breadth of sexual mechanisms including various forms of hermaphroditism. Sparidae is a fish family exhibiting gonochorism or hermaphroditism even in closely related species. The sparid Diplodus puntazzo (sharpsnout seabream), exhibits rudimentary hermaphroditism characterized by intersexual immature gonads but single-sex mature ones. Apart from the intriguing reproductive biology, it is economically important with a continuously growing aquaculture in the Mediterranean Sea, but limited available genetic resources. Our aim was to characterize the expressed transcriptome of gonads and brains through RNA-Sequencing and explore the properties of genes that exhibit sex-biased expression profiles. Results: Through RNA-Sequencing we obtained an assembled transcriptome of 82,331 loci. The expression analysis uncovered remarkable differences between male and female gonads, while male and female brains were almost identical. Focused search for known targets of sex determination and differentiation in vertebrates built the sex-specific expression profile of sharpsnout seabream. Finally, a thorough genetic marker discovery pipeline led to the retrieval of 85,189 SNPs and 29,076 microsatellites enriching the available genetic markers for this species. Conclusions: We obtained a nearly complete source of transcriptomic sequence as well as marker information for sharpsnout seabream, laying the ground for understanding the complex process of sex differentiation of this economically valuable species. The genes involved include known candidates from other vertebrate species, suggesting a conservation of the toolkit between gonochorists and hermaphrodites