COVID-19 and its consequences on mental health (Review).

As one year is approaching since the beginning of the Coronavirus disease 2019 (COVID-19) pandemic, it is important to acknowledge the detrimental effect that it is having on mental health at the individual, societal and public health levels. The current review presents the direct and indirect psychological impact of COVID-19 on the general public, as well as on vulnerable groups, including the elderly, the young, healthcare professionals, people with pre-existing mental health issues, those infected by COVID-19, homeless people and refugees. Important findings are discussed in the present review, including the social stigma in older people associated with portraying COVID-19 as the disease of the elderly, and the limited psychological impact of COVID-19 in the severely mentally ill, alongside the response of the mental healthcare systems globally to this unparalleled public health crisis. The important lessons to be learnt so far can help formulate individual mental health recommendations, as well as improved intervention and prevention public health strategies

The Maintenance of Traditions in Marmosets: Individual Habit, Not Social Conformity? A Field Experiment

Social conformity is a cornerstone of human culture because it accelerates and maintains the spread of behaviour within a group. Few empirical studies have investigated the role of social conformity in the maintenance of traditions despite an increasing body of literature on the formation of behavioural patterns in non-human animals. The current report presents a field experiment with free-ranging marmosets (Callithrix jacchus) which investigated whether social conformity is necessary for the maintenance of behavioural patterns within groups or whether individual effects such as habit formation would suffice.Using a two-action apparatus, we established alternative behavioural patterns in six family groups composed of 36 individuals. These groups experienced only one technique during a training phase and were thereafter tested with two techniques available. The monkeys reliably maintained the trained method over a period of three weeks, despite discovering the alternative technique. Three additional groups were given the same number of sessions, but those 21 individuals could freely choose the method to obtain a reward. In these control groups, an overall bias towards one of the two methods was observed, but animals with a different preference did not adjust towards the group norm. Thirteen of the fifteen animals that discovered both techniques remained with the action with which they were initially successful, independent of the group preference and the type of action (Binomial test: exp. proportion: 0.5, p<0.01).The results indicate that the maintenance of behavioural patterns within groups 1) could be explained by the first rewarded manipulation and subsequent habit formation and 2) do not require social conformity as a mechanism. After an initial spread of a behaviour throughout a group, this mechanism may lead to a superficial appearance of conformity without the involvement of such a socially and cognitively complex mechanism. This is the first time that such an experiment has been conducted with free-ranging primates

Frequent COL4 mutations in familial microhematuria accompanied by later-onset Alport nephropathy due to focal segmental glomerulosclerosis

Familial microscopic hematuria (FMH) is associated with a genetically heterogeneous group of conditions including the collagen-IV nephropathies, the heritable C3/CFHR5 nephropathy and the glomerulopathy with fibronectin deposits. The clinical course varies widely, ranging from isolated benign familial hematuria to end-stage renal disease (ESRD) later in life. We investigated 24 families using Next Generation Sequencing (NGS) for five genes: COL4A3, COL4A4, COL4A5, CFHR5 and FN1. In 17 families (71%), we found 15 pathogenic mutations in COL4A3/A4/A5, nine of them novel. In five families patients inherited classical AS with hemizygous X-linked COL4A5 mutations. Even more patients developed later-onset Alport-related nephropathy having inherited heterozygous COL4A3/A4 mutations that cause thin basement membranes. Amongst 62 heterozygous or hemizygous patients, eight (13%) reached ESRD, while 25% of patients with heterozygous COL4A3/A4 mutations, aged >50-yrs, reached ESRD. In conclusion, COL4A mutations comprise a frequent cause of FMH. Heterozygous COL4A3/A4 mutations predispose to renal function impairment, supporting that thin basement membrane nephropathy is not always benign. The molecular diagnosis is essential for differentiating the X-linked from the autosomal recessive and dominant inheritance. Finally, NGS technology is established as the gold standard for the diagnosis of FMH and associated collagen-IV glomerulopathies, frequently averting the need for invasive renal biopsies

A barrier to homologous recombination between sympatric strains of the cooperative soil bacterium Myxococcus xanthus

The bacterium Myxococcus xanthus glides through soil in search of prey microbes, but when food sources run out, cells cooperatively construct and sporulate within multicellular fruiting bodies. M. xanthus strains isolated from a 16 × 16-cm-scale patch of soil were previously shown to have diversified into many distinct compatibility types that are distinguished by the failure of swarming colonies to merge upon encounter. We sequenced the genomes of 22 isolates from this population belonging to the two most frequently occurring multilocus sequence type (MLST) clades to trace patterns of incipient genomic divergence, specifically related to social divergence. Although homologous recombination occurs frequently within the two MLST clades, we find an almost complete absence of recombination events between them. As the two clades are very closely related and live in sympatry, either ecological or genetic barriers must reduce genetic exchange between them. We find that the rate of change in the accessory genome is greater than the rate of amino-acid substitution in the core genome. We identify a large genomic tract that consistently differs between isolates that do not freely merge and therefore is a candidate region for harbouring gene(s) responsible for self/non-self discrimination

Political travel across the ‘Iron Curtain’ and Communist youth identities in West Germany and Greece in the 1970s and 1980s

This article explores tours through the Iron Curtain arranged by West German and Greek pro-Soviet Communist youth groups, in an attempt to shed light on the transformation of European youth cultures beyond the ‘Americanisation’ story. It argues that the concept of the ‘black box’, employed by Rob Kroes to describe the influence of American cultural patterns on Western European youth, also applies to the reception of Eastern Bloc policies and norms by the Communists under study. Such selective reception was part of these groups’ efforts to devise a modernity alternative to the ‘capitalist’ one, an alternative modernity which tours across the Iron Curtain would help establish. Nevertheless, the organisers did not wish such travel to help eliminate American/Western influences on youth lifestyles entirely: the article analyses the excursions’ aims with regard to two core components of youth lifestyles in Western Europe since the 1960s, which have been affected by intra-Western flows, the spirit of ‘doing one’s own thing’ and transformations of sexual practices. The article also addresses the experience of the travellers in question, showing that they felt an unresolved tension: the tours neither served as a means of Sovietisation nor as an impulse to develop an openly anti-Soviet stance.PostprintPeer reviewe

Exploring the possibility of reducing the energy demands of ships electric motors by using power electrinics.

136 σ.Στο πλαίσιο της συνεχούς προσπάθειας μείωσης του λειτουργικού κόστους των πλοίων, αλλά και της εναρμόνισης με τους κανονισμούς του Διεθνή Ναυτιλιακού Οργανισμού (ΙΜΟ), εξετάζονται διάφοροι μηχανισμοί και διερευνώνται διάφορες μέθοδοι με σκοπό τη μείωση του ενεργειακού αποτυπώματος των πλοίων. Προκειμένου να διερευνηθεί η δυνατότητα μείωσης των ενεργειακών απαιτήσεων ενός επαγωγικού κινητήρα με περιέλιξη κλωβού στην κατάσταση μόνιμης λειτουργίας εξετάζεται η σκοπιμότητα χρήσης ηλεκτρονικών ισχύος. Εξαιτίας τούτου αναπτύχθηκε μία πειραματική διάταξη όπου, ένας μικρός, τριφασικός επαγωγικός κινητήρας ονομαστικής ισχύος 175 W, συνδέεται με ένα ηλεκτροδυναμόμετρο, που προσομοιώνει μια βοηθητική αντλία επάνω σε πλοίο. Αρχικά η τροφοδότηση του κινητήρα γίνεται απευθείας από την τριφασική πηγή τάσης, ενώ στο επόμενο στάδιο γίνεται μέσω του ηλεκτρονικού ισχύος που παρεμβάλλεται μεταξύ της πηγής τάσεως και του κινητήρα. Οι λειτουργικές παράμετροι της διάταξης καταγράφονται και μετά την επεξεργασία τους μελετάται η απόδοση του συστήματος μετατροπέα-ηλεκτροκινητήρα-ηλεκτροδυναμομέτρου. Μετρήσεις λήφθησαν για τις παρακάτω καταστάσεις: • Χωρίς λειτουργία του μετατροπέα ισχύος, • Με λειτουργία του μετατροπέα ισχύος με ρύθμιση τάσεως-συχνότητας με βάση το επίπεδο ζήτησης μηχανικού φορτίου, • Με λειτουργία του μετατροπέα ισχύος χωρίς ρύθμιση τάσεως-συχνότητας. Οι μετρήσεις λήφθησαν για διάφορα επίπεδα ισχύος μηχανικού φορτίου από 0% έως και 120% του «ονομαστικού μηχανικού φορτίου», το οποίο ορίζεται ως το μηχανικό φορτίο που αποδίδεται στο ηλεκτροδυναμόμετρο υπό τις ονομαστικές συνθήκες λειτουργίας τάσης και ρεύματος του επαγωγικού κινητήρα. Από την επεξεργασία των μετρήσεων προέκυψε ότι σε χαμηλά επίπεδα φόρτισης του ηλεκτροδυναμόμετρου (έως περίπου 60%) η χρήση μετατροπέα ισχύος με ρυθμιζόμενη τάση-συχνότητα με βάση το επίπεδο του μηχανικού φορτίου οδηγεί σε εξοικονόμηση ηλεκτρικής ενέργειας ως και 35%. .Following a constant attempt to reduce the functional cost of ships while abiding by the regulations of the International Maritime Organization (IMO), a number of mechanisms are being examined and a number of methods are being studied which aim at reducing the ships carbon footprint. In order to explore the possibility of reducing the energy demands of squirrel induction motor in permanent operation, the use of power electronics is being considered. For the purpose of our study, we have developed an experimental arrangement where a small, three-phase squirrel induction motor of nominal power 175W is connected to an electrodynamometer, which simulates an auxiliary pump aboard a ship. Initially, the motor is powered directly from the three-phase voltage source, while at the next stage this is achieved by the electronic power which comes in between the voltage source and the motor. Once the functional parameters of this arrangement have been recorded and processed, the performance of the system converter-electromotor- electrodynamometer is being studied. We have measured and recorded the operational parameters of the following situations: • Without the power converter in operation • With the power converter in operation adjusting voltage and frequency according to the demand level of the mechanical load • With the power converter in operation without adjusting voltage and frequency The measurements obtained refer to various levels of the power mechanical load ranging from 0% to 120% of the “nominal mechanical load”, which is defined as the mechanical load attributed to the electrodynamometer under the nominal operational conditions of voltage and power of the induction motor. After processing the measurements, we have concluded that in low load levels of the electrodynamometer (up to about 60%), the use of a power converter adjusting voltage and frequency according to the level of the mechanical load reduces energy consumption up to 35%.Θεμιστοκλής Ν. Νικολακάκη

Development of a control drive for DC motors capable of current and position control

70 σ.This work concerns the design and implementation of a set-up consisting of electronic elements, which can either control the current flowing through a DC servomotor, or the position of its axle. The purpose of implementing such a design is to use it in a four-legged robot later on. It must be able to receive a current or position command from the robot‟s main control unit, and apply a certain type of control to the robot‟s motors. This must be done according to certain specifications concerning the volume, weight, power and response of the final setup. In the beginning, we design the setup from a theoretical point of view, not using specific components, but blocks with certain functionality. Next comes the translation of these blocks into electronic components having the same functionality. We select specific components which are capable of delivering results equal or better to the desired specifications. The control algorithm is implemented using a microprocessor. Programming the microprocessor is a large part of this work. After designing the setup and connecting the components together, we created an IC board with all the required parts. The whole control system is calibrated and the setup is tested to see if the required specifications have been met. Finally these test results are presentedΗ εργασία αυτή περιλαμβάνει την μελέτη, σχεδίαση και υλοποίηση μιας ολοκληρωμένης διάταξης ηλεκτρονικών η οποία μπορεί να ελέγξει είτε το ρεύμα που διαρρέει έναν σερβοκινητήρα συνεχούς ρεύματος και κατ? επέκταση την ροπή που αυτός ασκεί, είτε την θέση της ατράκτου του. Τελικός σκοπός είναι η χρήση της διάταξης που θα αναπτύξουμε σε ένα τετράποδο ρομπότ. Συγκεκριμένα θα λαμβάνει εντολές από το κεντρικό σύστημα ελέγχου και θα πρέπει να εφαρμόζει τον απαιτούμενο έλεγχο στους κινητήρες των ποδιών του ρομπότ. Η ανάπτυξη της διάταξης γίνεται με βάση συγκεκριμένες προδιαγραφές οι οποίες αφορούν τον όγκο, βάρος, ισχύ και απόκριση του τελικού αποτελέσματος. Αρχικά γίνεται ο σχεδιασμός της διάταξης σε θεωρητικό επίπεδο, δηλαδή εξετάζεται επισκοπικά ο τρόπος λειτουργίας της. Καταλήγουμε σε ένα σύστημα ελέγχου το οποίο αποτελείται από ορισμένα υποσυστήματα. Στην συνέχεια εξετάζουμε τον τρόπο υλοποίησης των υποσυστημάτων αυτών με ηλεκτρονικά κυκλώματα. Ακολουθεί η επιλογή των ηλεκτρονικών κυκλωμάτων έτσι ώστε να μπορεί η τελική διάταξη να πληροί τις προδιαγραφές που έχουν οριστεί αρχικά. Μετά την σύνδεση των επιμέρους τμημάτων υλοποιείται ο ελεγκτής με την βοήθεια μικροεπεξεργαστή. Ένα πολύ μεγάλο μέρος της εργασίας αυτής περιλαμβάνει τον προγραμματισμό του μικροεπεξεργαστή έτσι ώστε να εφαρμόζεται αποδοτικά ο απαιτούμενος έλεγχος. Μετά από τον σχεδιασμό της συνολικής διάταξης και τον προγραμματισμό του μικροελεγκτή υλοποιείται η ηλεκτρονική πλακέτα που περιλαμβάνει όλα τα ηλεκτρονικά κυκλώματα που απαιτούνται για την λειτουργία της διάταξης. Αφού γίνει βελτιστοποίηση των παραμέτρων του κυκλώματος, εξετάζουμε αν η λειτουργία της διάταξης είναι ικανοποιητική με βάση τις προδιαγραφές που έχουμε ορίσει. Αυτό γίνεται υποβάλλοντας την διάταξη σε δοκιμές με βάση τα πραγματικά δεδομένα. Στην συνέχεια παρουσιάζονται τα αποτελέσματα αυτά.Αλέξανδρος Ν. Νικολακάκη