Showing papers by "University of the Aegean published in 2022"

Potential Impacts of Climate Change on the Habitat Suitability of the Dominant Tree Species in Greece

Abstract: Climate change is affecting species distribution and ecosystem form and function. Forests provide a range of ecosystem services, and understanding their vulnerability to climate change is important for designing effective adaptation strategies. Species Distribution Modelling (SDM) has been extensively used to derive habitat suitability maps under current conditions and project species distribution shifts under climate change. In this study, we model the current and future habitat suitability of the dominant tree species in Greece (Abies cephalonica, Abies borisii-regis, Pinus brutia, Pinus halepensis, Pinus nigra, Quercus ilex, Quercus pubescens, Quercus frainetto and Fagus sylvatica), based on species-specific presence data from the EU-Forest database, enhanced with data from Greece that is currently under-represented in terms of tree species occurrence points. By including these additional presence data, areas with relatively drier conditions for some of the study species were included in the SDM development, yielding a potentially lower vulnerability under climate change conditions. SDMs were developed for each taxon using climate and soil data at a resolution of ~1 km2. Model performance was assessed under current conditions and was found to adequately simulate potential distributions. Subsequently, the models were used to project the potential distribution of each species under the SSP1-2.6 and SSP5-8.5 scenarios for the 2041-2070 and 2071-2100 time periods. Under climate change scenarios, a reduction in habitat-suitable areas was predicted for most study species, with higher elevation taxa experiencing more pronounced potential habitat shrinkages. An exception was the endemic A. cephalonica and its sister species A. borisii-regis, which, although currently found at mid and high elevations, seem able to maintain their potential distribution under most climate change scenarios. Our findings suggest that climate change could significantly affect the distribution and dynamics of forest ecosystems in Greece, with important ecological, economic and social implications, and thus adequate mitigation measures should be implemented.

The impact of the COVID-19 pandemic upon employment and inequality in the Mediterranean EU: An early look from a Labour Geography perspective

Abstract: COVID-19 is a global pandemic but has a particular geography to it, differentially affecting people and places. Here we explore its impact upon labour markets in the Mediterranean European Union (E...

A multiscale quasilinear system for colloids deposition in porous media: Weak solvability and numerical simulation of a near-clogging scenario

Abstract: We study the weak solvability of a macroscopic, quasilinear reaction–diffusion system posed in a 2 D porous medium which undergoes microstructural problems. The solid matrix of this porous medium is assumed to be made out of circles of not-necessarily uniform radius. The growth or shrinkage of these circles, which are governed by an ODE, has direct feedback to the macroscopic diffusivity via an additional elliptic cell problem. The reaction–diffusion system describes the macroscopic diffusion, aggregation, and deposition of populations of colloidal particles of various sizes inside a porous media made of prescribed arrangement of balls. The mathematical analysis of this two-scale problem relies on a suitable application of Schauder’s fixed point theorem which also provides a convergent algorithm for an iteration method to compute finite difference approximations of smooth solutions to our multiscale model. Numerical simulations illustrate the behavior of the local concentration of the colloidal populations close to clogging situations.

Reproduction in the Archipelago of the Aegean 1920–2016: Long-Term Trends and Recent Upturns:

Abstract: Little is known about the reproductive behavior of the population in insular Greece because of the lack of reliable and unintermittent time series of vital statistics. By applying methods used in h...

In situ control of graphene oxide dispersions with a small impedance sensor

Abstract: Carbon-based nanomaterials (CBNs), such as graphene and carbon nanotubes, display advanced physical and chemical properties, which has led to their widespread applications. One of these applications includes the incorporation of CBNs into cementitious materials in the form of aqueous dispersions. The main issue that arises in this context is that currently no established protocol exists as far as characterizing the dispersions. In the present article, an innovative method for quick evaluation and quantification of graphene oxide (GO) dispersions is proposed. The proposed method is electrical impedance spectroscopy (EIS) with an impedance sensor. The novelty lies on the exploitation of a small sensor for on-site (field) direct dielectric measurements with the application of alternating current. Five different concentrations of GO dispersions were studied by applying EIS and for various accumulated ultrasonic energies. The low GO concentration leads to high impedance values due to low formed current network. Two opposing mechanisms were revealed during the accumulation of ultrasonic energy, that are taking place simultaneously: breakage of the agglomerates that facilitates the flow of the electric current due to the formation of a better dispersed network, nevertheless the surface hydrophilic structure of the GO is damaged with the high accumulated ultrasonic energy. The dielectric measurements were exploited to express an appropriate quantitative 'quality index' to facilitate with the dispersion control of the nanostructures. An intermediate concentration of GO is suggested (about 0.15 wt% of the binder materials) to be optimal for the specific engineering application, ultrasonicated at approximately 30 to 65 kJ. The investigated methodology is highly novel and displays a high potential to be applied in-field applications where CBNs must be incorporated in building materials.

A transcriptome-wide association study identifies novel candidate susceptibility genes for prostate cancer risk

Abstract: A large proportion of heritability for prostate cancer risk remains unknown. Transcriptome-wide association study combined with validation comparing overall levels will help to identify candidate genes potentially playing a role in prostate cancer development. Using data from the Genotype-Tissue Expression Project, we built genetic models to predict normal prostate tissue gene expression using the statistical framework PrediXcan, a modified version of the unified test for molecular signatures, and Joint-Tissue Imputation. We applied these prediction models to the genetic data of 79,194 prostate cancer cases and 61,112 controls to investigate the associations of genetically determined gene expression with prostate cancer risk. Focusing on associated genes, we compared their expression in prostate tumor versus normal prostate tissue, compared methylation of CpG sites located at these loci in prostate tumor versus normal tissue, and assessed the correlations between the differentiated genes' expression and the methylation of corresponding CpG sites, by analyzing The Cancer Genome Atlas (TCGA) data. We identified 573 genes showing an association with prostate cancer risk at a false discovery rate (FDR) ≤ 0.05, including 451 novel genes and 122 previously reported genes. Of the 573 genes, 152 showed differential expression in prostate tumor versus normal tissue samples. At loci of 57 genes, 151 CpG sites showed differential methylation in prostate tumor versus normal tissue samples. Of these, 20 CpG sites were correlated with expression of 11 corresponding genes. In this TWAS, we identified novel candidate susceptibility genes for prostate cancer risk, providing new insights into prostate cancer genetics and biology. This article is protected by copyright. All rights reserved.

Upcycling Systems Design, Developing a Methodology through Design

Abstract: Design has an important role in shaping the modes of production, consumption and disposal. Decisions made early in the product, service and system development influence the majority of the environmental impact and social consequences. With sustainability emerging as the major challenge of our times, the creation of novel methodologies, economic models and innovative materials is critical. In this paper, we put forward a new methodology that aims to bridge the ecomodernist business-focused circular economy models with the expressive material driven design (MDD) approach. The ‘design out waste methodology’ (DOWM) bridges existing concepts, methods and practices, creating an innovative design and production process that redefines waste and sets it up as a subject of creative study. The purpose of this process is to help designers understand the importance of evaluating the entire life cycle of a product; it also enables local ‘degrowth’ by shifting our modes of production towards a human scale with local makers exchanging knowledge and expressing themselves through upcycled materials, while simultaneously eradicating the very concept of waste. The methodology has been developed in an iterative research-through-design process that combines experiential and tacit knowledge from local case studies with desk research of emerging case studies in MDD.

Liver Ultrasound Attenuation

Abstract: Nonalcoholic fatty liver disease (NAFLD) is the most widespread chronic liver disease type in the Western countries. Ultrasound (US) is used for NAFLD and hepatic steatosis (HS) grading. The most popular US method for NAFLD assessment is the hepatorenal index (HRI), but because of its limitations, other noninvasive methods have been developed. The Resona 7 US system has recently incorporated an US attenuation-related quantitative feature, liver ultrasound attenuation (LiSA), for HS estimation. The purpose of this study is to compare LiSA's and HRI's performance on NAFLD assessment.A total of 159 NAFLD patients having a magnetic resonance imaging-proton density fat fraction (MRI-PDFF) examination were examined by 2 radiologists, who performed LiSA and HRI measurements in the liver. Correlation of LiSA's and HRI's measurements with MRI-PDFF values was calculated through Pearson correlation coefficient (PCC). To further investigate the performance of LiSA and HRI, optimum cutoffs, provided by the literature, were used to correspond HS grades to MRI-PDFF results. Moreover, a receiver operating characteristic (ROC) analysis on LiSA measurements and steatosis grades was performed.Magnetic resonance imaging-PDFF was better correlated with LiSA (PCC = 0.80) than HRI (PCC = 0.67). Receiver operating characteristic analysis showed better performance range for LiSA (77.8%-91.8%) than for HRI (72.8%-85.4%) on all HS grades for all studies used for corresponding MRI-PDFF values to HS grades.The results indicate that LiSA is more accurate than HRI in HS differentiation and can lead to more accurate grading of HS on NAFLD patients.

An Exploratory Study of Mobile-Based Scenarios for Foreign Language Teaching in Early Childhood

Abstract: In today’s world, the ability to communicate in a foreign language is more highly prized than ever by prospective employers, which results in more options and possibilities for students, both academically and professionally. As a result of this tendency and the need for new communication methods, language instructors are driven to include cutting-edge language teaching approaches, resources, and materials in their classroom instruction, such as using ICT, or information, communication and ubiquitous technologies. In this paper, we introduce learning scenarios based on two mobile learning apps that facilitate language learning through interesting, interactive settings in a more personalized way based on children’s age. The writers’ emphasis will be on demonstrating interactive activities devised in their classrooms and on providing examples of student work in two languages, English and Spanish. Through this paper, we examine a range of educational tools and determine that Mondly Kids and Language Drops-Kahoot are the best acceptable teaching materials. On the basis of this assumption, we created three distinct groups of students, and the outcomes from the assessment technique show that mobile language learning enhances children’s experiences and increases their willingness to learn a new language. Additionally, students can use mobile applications to improve their speaking abilities and critical thinking skills throughout a language learning session.

Monitoring a BAR(1) Process with EWMA and DEWMA Control Charts

Abstract: In this work we study one-sided and two-sided EWMA and Double EWMA control charts for monitoring an integer-valued autocorrelated process with a bounded support. The performance of the proposed charts is studied via simulation. We compare the performance of the proposed charts and provide aspects for the statistical design and practical implementation. The results of an extensive numerical study, that consists of the examination of a wide variety of out-of-control situations, show that none of the chart outperforms the other uniformly. Specifically, both charts have a difficulty in detecting decreasing shifts in the autocorrelation parameter. An illustrative example based on real data is also provided.

Onset of synchronization in coupled Mixmaster oscillators

Abstract: We consider the problem of asymptotic synchronization of different spatial points coupled to each other in inhomogeneous space-time and undergoing chaotic Mixmaster oscillations towards the singularity. We demonstrate that for couplings larger than some threshold value, two Mixmaster spatial points [Formula: see text], with [Formula: see text] in the past of [Formula: see text], synchronize and thereby proceed in perfect unison towards the initial singularity. We further show that there is a Lyapunov function for the synchronization dynamics that makes different spatial points able to synchronize exponentially fast in the past direction. We provide an elementary proof of how an arbitrary spatial point responds to the mean field created by the oscillators, leading to their direct interaction through spontaneous synchronization. These results ascribe a clear physical meaning of early-time synchronization leading to a resetting effect for the two BKL maps corresponding to two distinct oscillating spatial points, as the two maps converge to each other to become indistinguishable at the end of synchronization. Our results imply that the universe generically organizes itself through simpler, synchronized, states as it approaches the initial singularity. A discussion of further implications of early-time inhomogeneous Mixmaster synchronization is also provided. This article is part of the theme issue 'The future of mathematical cosmology, Volume 1'.

Uncovering patterns of public perceptions towards biodiversity crime using conservation culturomics

Abstract: This paper examines aspects of the relationship between (1) the recently typified form of biodiversity crime, (2) information made available to the public through the Internet, and (3) cultural dynamics quantified through info-surveillance methods through Culturomics techniques. We propose two conceptual models: (1) the building-up process of a biodiversity crime culturome, in some language, and (2) a multi-stage biodiversity conservation chain and biodiversity-crime activities relating to each stage. We use crowd search volumes on the Internet on biodiversity crime-related terms and topics as proxies for measuring public interest. The main findings are: (1) the concept of biodiversity-crime per se is still immature and presents low penetration to the general public; (2) biodiversity-crime issues, not recognized as such, are amalgamated in conservation-oriented websites and pages; and (3) differences in perceptions and priorities between general vs. niche public with particular interest(s) in environmental issues- are discernable.

Ανθεκτικότητα, νόημα στη ζωή και αυτοαποτελεσματικότητα σε οικογένειες με ή χωρίς μέλος με ειδικές εκπαιδευτικές ανάγκες και αναπηρία στην πανδημία COVID-19

Abstract: Η παρούσα εργασία είχε ως στόχο να διερευνήσει τις συνέπειες της πανδημίας της νόσου COVID-19, καθώς και τον βαθμό ανθεκτικότητας, νοήματος ζωής και αυτοαποτελεσματικότητας σε οικογένειες με ή χωρίς μέλος με ειδικές εκπαιδευτικές ανάγκες και αναπηρία (ε.ε.α./α.). Συμμετείχαν 411 άτομα, 130 άνδρες και 281 γυναίκες, εκ των οποίων οι 217 ήταν γονείς και οι 194 ήταν παιδιά (φοιτητές/τριες), που φοιτούσαν στο 3ο και 4ο έτος σπουδών. Η ηλικία των συμμετεχόντων/ουσών ήταν 20-60 έτη. Για τη συλλογή των δεδομένων χορηγήθηκαν ένα Αυτοσχέδιο Ερωτηματολόγιο, η Κλίμακα Ανθεκτικότητας, το Ερωτηματολόγιο Νοήματος Zωής και η Γενική Κλίμακα Αυτοαποτελεσματικότητας. Τα ευρήματα κατέδειξαν ότι κανένας/καμία από τους/τις συμμετέχοντες/ουσες δεν είχε διαγνωστεί με τη νόσο COVID-19 ή υπήρξε ως ύποπτο κρούσμα. Η πλειονότητα των συμμετεχόντων/ουσών ανέφερε πως συμφωνεί ή συμφωνεί απόλυτα ότι η πανδημία έχει επηρεάσει την καθημερινή τους ζωή, με θετικές και αρνητικές συνέπειες. Συνάμα, εμφάνισαν μέτριο βαθμό ανθεκτικότητας και υψηλό βαθμό νοήματος ζωής και αυτοαποτελεσματικότητας. Στατιστικά σημαντικές διαφορές εντοπίστηκαν: α) ανάμεσα στις οικογένειες με και χωρίς μέλος με ε.ε.α./α., όπου στις οικογένειες με μέλος με ε.ε.α./α. βρέθηκε υψηλότερη ανθεκτικότητα, και β) ανάμεσα σε γονείς και φοιτητές/τριες όσον αφορά στον βαθμό ανθεκτικότητας και στο νόημα στη ζωή στις δύο διαστάσεις (παρουσία και αναζήτηση). Eπιπλέον, βρέθηκαν στατιστικά σημαντικές διαφορές με βάση την ύπαρξη ή μη μέλους με ε.ε.α./α. στην οικογένεια σε συνδυασμό με την ηλικιακή ομάδα στις μεταβλητές της ανθεκτικότητας και του νοήματος στη ζωή. Τέλος, βρέθηκε ότι υπήρχε στατιστικά σημαντική θετική συσχέτιση ανάμεσα στις συνέπειες της πανδημίας της νόσου COVID-19 με τη συνολική ανθεκτικότητα και την παρουσία νοήματος στη ζωή. H μελέτη προτείνει ότι η πανδημία έχει πολλαπλές συνέπειες τόσο στο άτομο όσο και στην οικογένεια, και σε μία περίοδο υγειονομικής κρίσης τα άτομα ενεργοποιούν προστατευτικούς μηχανισμούς και στρατηγικές, που μπορούν να ενισχύσουν την ψυχική και σωματική τους υγεία, σε ατομικό και οικογενειακό επίπεδο.

IOHIVE: Design Requirements for a System that Supports Interactive Journaling for Beekeepers During Apiary Inspections

Abstract: In this paper, we present an ongoing project that focuses on designing interactive systems and their respective interfaces for monitoring and journaling of apiculture information acquired in the actual field during apiary inspections by the beekeepers. Initially, the paper provides a brief overview of the concepts and technologies found in the domain. Next, it examines the scenarios to be used for the design of interactions related to the actual beehive inspections and desktop use in the office. The paper mainly focuses on the design requirements based on user research. It provides a review of interaction techniques that can be implemented for journaling in the workplace of the apiary, briefly outlines the infrastructure and gives a system overview at its current state of development. Finally, the paper discusses future work including, guidelines towards the development of the various system components for journaling and a preliminary evaluation plan for the case studies that will follow.