cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
An evolutionary model for the gamma-ray system PSR J1311-3430 and its companion
Creators: name: Benvenuto, O. G.
name: De Vito, M. A.
name: Horvath, J. E.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: The most recent member of the millisecond pulsar with very low-mass companions and short orbital periods class, PSR J1311-3430 (Pletsch et al. 2012) is a remarkable object in various senses. Besides being the first discovered in gamma-rays, its measured features include the very low or absent hydrogen content. We show in this Letter that this important piece of information leads to a very restricted range of initial periods for a given donor mass. For that purpose, we calculate in detail the evolution of the binary system self-consistently, including mass transfer and evaporation, finding the features of the new evolutionary path leading to the observed configuration. It is also important to remark that the detailed evolutionary history of the system naturally leads to a high final pulsar mass, as it seems to be demanded by observations.
description: 5 pages, 5 figures, 1 table. Accepted for publication in MNRAS Letters
Bott-Chern cohomology and q-complete domains
Creators: name: Angella, Daniele
name: Calamai, Simone
Publisher: name: arXiv
Year: 2013
Subjects: subject: Complex Variables (math.CV)
subject: Differential Geometry (math.DG)
subject: FOS: Mathematics
subject: 32C35, 32F17, 55N30

description: In studying the Bott-Chern and Aeppli cohomologies for q-complete manifolds, we introduce the class of cohomologically Bott-Chern q-complete manifolds.
title: Analysis, design and study of flexible solar systems
title: Ανάλυση, σχεδιασμός και μελέτη εύκαμπτων ηλιακών συστημάτων
titleType: AlternativeTitle
Creators: name: Ντ'ονόφριο, Κρίστιαν
Publisher: name: Πανεπιστήμιο Δυτικής Αττικής
Year: 2023
Subjects: Flexible solar systems
Renewable energy sources
Solar energy
Photovoltaic systems
Flexible solar cells
Organic solar cells

description: The purpose of this thesis is to analyze the current situation and to study the development possibilities presented in the field of flexible photovoltaic systems, in the light of their inclusion in modern societies in a sustainable, economic, efficient and aesthetically acceptable way. A bibliographic research of the materials and systems that have already been studied will be carried out as well as laboratory tests of innovative materials in order to draw conclusions and results about their behavior and efficiency. The part of integrating photovoltaic systems into fabrics and the possibilities that can be created from it will also be studied. The intention is to design and study proposals for photovoltaic systems for various uses. The entire research will be aimed at the development of a socially acceptable integration of systems that will use solar energy to supply the energy needs that exist in as many sectors as possible.
Rate of Belowground Carbon Allocation Differs with Successional Habit of Two Afromontane Trees
Creators: name: Shibistova, Olga
name: Yohannes, Yonas
name: Boy, Jens
name: Richter, Andreas
name: Wild, Birgit
name: Watzka, Margarete
name: Guggenberger, Georg
Publisher: name: San Francisco : Public Library Science
Year: 2012
Subjects: subject: high temporal resolution
subject: soil respiration
subject: isotope composition
subject: southern ethiopia
subject: gas-exchange
subject: terrestrial ecosystems
subject: physiological ecology
subject: organic-compounds
subject: tropical forests
subject: fagus-sylvatica
subject: Dewey Decimal Classification::500 | Naturwissenschaften::580 | Pflanzen (Botanik)
subject: Dewey Decimal Classification::500 | Naturwissenschaften

description: Background: Anthropogenic disturbance of old-growth tropical forests increases the abundance of early successional tree species at the cost of late successional ones. Quantifying differences in terms of carbon allocation and the proportion of recently fixed carbon in soil CO2 efflux is crucial for addressing the carbon footprint of creeping degradation. Methodology: We compared the carbon allocation pattern of the late successional gymnosperm Podocarpus falcatus (Thunb.) Mirb. and the early successional (gap filling) angiosperm Croton macrostachyus Hochst. es Del. in an Ethiopian Afromontane forest by whole tree (CO2)-C-13 pulse labeling. Over a one-year period we monitored the temporal resolution of the label in the foliage, the phloem sap, the arbuscular mycorrhiza, and in soil-derived CO2. Further, we quantified the overall losses of assimilated C-13 with soil CO2 efflux. Principal Findings: C-13 in leaves of C. macrostachyus declined more rapidly with a larger size of a fast pool (64% vs. 50% of the assimilated carbon), having a shorter mean residence time (14 h vs. 55 h) as in leaves of P. falcatus. Phloem sap velocity was about 4 times higher for C. macrostachyus. Likewise, the label appeared earlier in the arbuscular mycorrhiza of C. macrostachyus and in the soil CO2 efflux as in case of P. falcatus (24 h vs. 72 h). Within one year soil CO2 efflux amounted to a loss of 32% of assimilated carbon for the gap filling tree and to 15% for the late successional one. Conclusions: Our results showed clear differences in carbon allocation patterns between tree species, although we caution that this experiment was unreplicated. A shift in tree species composition of tropical montane forests (e. g., by degradation) accelerates carbon allocation belowground and increases respiratory carbon losses by the autotrophic community. If ongoing disturbance keeps early successional species in dominance, the larger allocation to fast cycling compartments may deplete soil organic carbon in the long run.
A Study on the Open Source Digital Library Software's: Special Reference to DSpace, EPrints and Greenstone
Creators: name: Tramboo, Shahkar
name: Humma
name: Shafi, S M
name: Gul, Sumeer
Publisher: name: arXiv
Year: 2012
Subjects: subject: Digital Libraries (cs.DL)
subject: FOS: Computer and information sciences

description: The richness in knowledge has changed access methods for all stake holders in retrieving key knowledge and relevant information. This paper presents a study of three open source digital library management software used to assimilate and disseminate information to world audience. The methodology followed involves online survey and study of related software documentation and associated technical manuals.
description: 9 Pages, 3 Figures, 1 Table, "Published with International Journal of Computer Applications (IJCA)"
title: Η καινοτομία και η συμβολή του διαδικτύου στον τουρισμό
title: The innovation and contribution of internet to tourism
titleType: AlternativeTitle
Creators: name: Γεώργα, Δήμητρα
Publisher: name: Πανεπιστήμιο Πειραιώς
Year: 2023
Subjects: subject: Τουρισμός
subject: Καινοτομία
subject: Διαδίκτυο
subject: Επιχείρηση
subject: Marketing
subject: FOS: Economics and business

description: Η παρούσα διπλωματική εργασία εκπονήθηκε στα πλαίσια του μεταπτυχιακού προγράμματος σπουδών του τμήματος Οικονομικής Επιστήμης του Πανεπιστημίου Πειραιώς και συγκεκριμένα του προγράμματος Εφαρμοσμένης Δημόσιας Οικονομικής και Πολιτικής και έχει ως θέμα την καινοτομία στον τουριστικό τομέα και την εξέλιξη της, ένα θέμα που έχει απασχολήσει ιδιαίτερα τους ερευνητές και του επιστήμονες με το πέρασμα του χρόνου. Στη συγκεκριμένη διπλωματική εργασία αναλύουμε την έννοια του τουρισμού, του τουριστικού προϊόντος και της καινοτομίας. Γίνεται εκτενής ανάλυση του φαινομένου του ηλεκτρονικού τουρισμού και της συμβολής του διαδικτύου στην εξέλιξη του τουριστικού κλάδου. Μελετήσαμε τις καινοτομίες στο τομέα του τουρισμού και πόσο το διαδίκτυο έχει αλλάξει τις συνθήκες και τους τρόπους με τους οποίους οι τουρίστες αναζητούν και αναλύουν τις διαθέσιμες επιλογές που έχουν. Τέλος, για την ανάλυσή μας χρησιμοποιήσαμε σαν εργαλεία έρευνας ερωτηματολόγια τα οποία είχαν σαν στόχο να αντιληφθούμε πώς οι τουρίστες επιλέγουν τους προορισμούς και ποιες καινοτόμες μεθόδους εμπιστεύονται για να οργανώσουν το ταξίδι τους.
Galaxy halo truncation and Giant Arc Surface Brightness Reconstruction in the Cluster MACSJ1206.2-0847
Creators: name: Eichner, Thomas
name: Seitz, Stella
name: Suyu, Sherry H.
name: Halkola, Aleksi
name: Umetsu, Keiichi
name: Zitrin, Adi
name: Coe, Dan
name: Monna, Anna
name: Rosati, Piero
name: Grillo, Claudio
name: Balestra, Italo
name: Postman, Marc
name: Koekemoer, Anton
name: Zheng, Wei
name: Høst, Ole
name: Lemze, Doron
name: Broadhurst, Tom
name: Moustakas, Leonidas
name: Bradley, Larry
name: Molino, Alberto
name: Nonino, Mario
name: Mercurio, Amata
name: Scodeggio, Marco
name: Bartelmann, Matthias
name: Benitez, Narciso
name: Bouwens, Rychard
name: Donahue, Megan
name: Infante, Leopoldo
name: Jouvel, Stephanie
name: Kelson, Daniel
name: Lahav, Ofer
name: Medezinski, Elinor
name: Melchior, Peter
name: Merten, Julian
name: Riess, Adam
Publisher: name: arXiv
Year: 2013
Subjects: subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: FOS: Physical sciences

description: In this work we analyze the mass distribution of MACSJ1206.2-0847, especially focusing on the halo properties of its cluster members. The cluster appears relaxed in its X-ray emission, but has significant amounts of intracluster light which is not centrally concentrated, suggesting that galaxy-scale interactions are still ongoing despite the overall relaxed state. The cluster lenses 12 background galaxies into multiple images and one galaxy at $z=1.033$ into a giant arc and its counterimage. The multiple image positions and the surface brightness distribution (SFB) of the arc which is bent around several cluster members are sensitive to the cluster galaxy halo properties. We model the cluster mass distribution with a NFW profile and the galaxy halos with two parameters for the mass normalization and extent of a reference halo assuming scalings with their observed NIR--light. We match the multiple image positions at an r.m.s. level of $0.85\arcsec$ and can reconstruct the SFB distribution of the arc in several filters to a remarkable accuracy based on this cluster model. The length scale where the enclosed galaxy halo mass is best constrained is about 5 effective radii -- a scale in between those accessible to dynamical and field strong lensing mass estimates on one hand and galaxy--galaxy weak lensing results on the other hand. The velocity dispersion and halo size of a galaxy with $m_{\rm 160W,AB}=19.2$ or $M_{\rm B,Vega}=-20.7$ are $σ=150 \rm kms^{-1}$ and $r\approx 26\pm 6 \rm kpc$, indicating that the halos of the cluster galaxies are tidally stripped. We also reconstruct the unlensed source (which is smaller by a factor of $\sim5.8$ in area), demonstrating the increase of morphological information due to lensing and conclude that this galaxy has likely star--forming spiral arms with a red (older) central component.
description: 34 pages, 18 figures, accepted by ApJ
MediPlEx - a tool to combine in silico & experimental gene expression profiles of the model legume Medicago truncatula
Medizinische und gesundheitsökonomische Bewertung der Radiochirurgie zur Behandlung von Hirnmetastasen
Creators: name: Henckel, Kolja
name: Küster, Helge
name: Stutz, Leonhard J.
name: Goesmann, Alexander
Publisher: name: London : Biomed Central Ltd.
Year: 2010
Subjects: subject: Medicago truncatula
subject: legume biology
subject: Expressed Sequence Tags
subject: Dewey Decimal Classification::500 | Naturwissenschaften

description: Background: Expressed Sequence Tags (ESTs) are in general used to gain a first insight into gene activities from a species of interest. Subsequently, and typically based on a combination of EST and genome sequences, microarray-based expression analyses are performed for a variety of conditions. In some cases, a multitude of EST and microarray experiments are conducted for one species, covering different tissues, cell states, and cell types. Under these circumstances, the challenge arises to combine results derived from the different expression profiling strategies, with the goal to uncover novel information on the basis of the integrated datasets. Findings: Using our new analysis tool, MediPlEx (MEDIcago truncatula multiPLe EXpression analysis), expression data from EST experiments, oligonucleotide microarrays and Affymetrix GeneChips® can be combined and analyzed, leading to a novel approach to integrated transcriptome analysis. We have validated our tool via the identification of a set of well-characterized AM-specific and AM-induced marker genes, identified by MediPlEx on the basis of in silico and experimental gene expression profiles from roots colonized with AM fungi. Conclusions: MediPlEx offers an integrated analysis pipeline for different sets of expression data generated for the model legume Medicago truncatula. As expected, in silico and experimental gene expression data that cover the same biological condition correlate well. The collection of differentially expressed genes identified via MediPlEx provides a starting point for functional studies in plant mutants.
Αργός τουρισμός : προοπτικές ανάπτυξης στην Ελλάδα
Creators: name: Βλάχου, Κωνσταντίνα
Publisher: name: Πανεπιστήμιο Πειραιώς
Year: 2023
Subjects: subject: Αργός τουρισμός
subject: Αργό κίνημα
subject: Μαζικός τουρισμός
subject: Αειφορία
subject: Ελλάδα

description: Σκοπός της παρούσας εργασίας αποτελεί η μελέτη του φαινομένου του Αργού Τουρισμού στην Ελλάδα. Στο πρώτο μέρος της εργασίας, αναλύονται κάποιες βασικές έννοιες που αφορούν τον τουρισμό ενώ γίνονται διακριτές οι συνέπειες του έως τώρα ευρέως χρησιμοποιούμενου μοντέλου του μαζικού τουρισμού. Τα περιβαλλοντικά, κοινωνικά και οικονομικά ζητήματα που εγείρει η διάδοση του μαζικού τουρισμού, οδήγησαν στην ανάγκη δημιουργίας νέων ειδικών μορφών τουρισμού. Ειδικότερα, εξετάζεται η ανάγκη για υιοθέτηση των πρακτικών της βιώσιμης ανάπτυξης στον τουριστικό τομέα, η οποία οδήγησε στην εφαρμογή του Αργού Κινήματος στον τουρισμό. Σε αυτό το πλαίσιο ο Αργός Τουρισμός, παρέχει τη δυνατότητα για επικοινωνία μεταξύ του επισκέπτη και του κατοίκου του προορισμού σε ένα αυθεντικό φυσικό και πολιτιστικό περιβάλλον. Στο δεύτερο μέρος της εργασίας, παρατίθενται τα αποτελέσματα της έρευνας που πραγματοποιήθηκε στο πλαίσιο της καλύτερης κατανόησης των προοπτικών ανάπτυξης του Αργού Τουρισμού στην Ελλάδα. Τέλος, παρουσιάζονται τα συμπεράσματα της εργασίας και γίνονται προτάσεις για την ανάπτυξη του Αργού Τουρισμού στην Ελλάδα.
Some Hadamard like inequalities via convex and s-convex functions and their applications for special means
Creators: name: Tunc, Mevlut
Publisher: name: arXiv
Year: 2013
Subjects: subject: Classical Analysis and ODEs (math.CA)
subject: FOS: Mathematics

description: In this study, the author establish some inequalities of Hadamard like based on convex and s-convexity in the second sense. Some applications to special means of positive real numbers are also given.
description: 11 pages
Pulsatilla halleri J. F. Gmelin
Creators: name: Becherer
Publisher: name: Zenodo
Year: 1956
Subjects: Biodiversity
Taxonomy

description: P. Halleri J. F. Gmelin (P. longiflora All.) Cat. 300. Verbreitung: Distr.3:Vispertäler(Mattertal und häufiger Saastal) und Simplonnordseite (selten); Distr. 3a: Simplonsüdseite; Distr. 4: Binntal (mehrfach) und Münstigertal (eine Fundstelle2). Die Angäbe JACCARD'S: «manque à l'ouest de la Viège, assez commun de la jusqu'au Münsterthal», ist, was den zweiten Teil betrifft, zu allgemein und darum irreführend. - Die Höhengrenzen sind: 1280 bis etwa 2500 m. JACCARD'S Angabe «1000m» als untere Grenze ist nicht berechtigt. 3: Neue Fundorte im Saastal: ob dem Heimischgarten (Romieux; Becherer und Thommen; Schatzmann), bei der Hofersalp (Becherer und Thommen), «Flühe» bei Zermeiggern (Frl. A. Weis), östlich der Eienalp (Thommen). - 3a: Neue Fundorte auf der Simplonsüdseite und Berichtigungen zu Jaccard's Angaben aus diesem Gebiet: Bei Simplon-Dorf (Becherer und Thommen); gegenüber Gabi am FUSS des Feerberges, 1280 m (Dübi 1930, Becherer u. a.), tiefste bekannte Fundstelle im Wallis; Südwesthang des Monte Camera, 2200-2400 m (Becherer). Die Jaccardschen Angaben «Steinersand (Venetz)» und «Laquintal, Feerberg (Joller)» beziehen sich wahrscheinlich auf die vorstehend genannte Stelle bei Gabi. Die Angabe «Gondo (Venetz)», die Jaccard vermutlich zu der Höhenbezeichnung «1000 m» bestimmt hat, muss sich auf das alpine Gebiet von Gondo (Alpien-Carnera oder Zwischbergental) beziehen, da bei Gondo die Art nicht vorkommt. Die Angäbe «Alpien (Wolf)» fällt vielleicht mit der oben genannten Angabe vom Monte Camera zusammen. Zu der Angabe «Bielti (Joller)», mit Bemerkung «très commun» (!), ist schliesslich zu sagen, dass der Verfasser dort die Art vergeblich gesuchthat. (Grenzgebiet: Südhang des Passo Possette ob Iselle, Italien, 2100 m [Dübi].) - 4: Neue Fundorte im Binntal: Eggerhorn (Mantz), Schinnern (idem), Galenalp (Binz, Becherer u. a.).
description: Published as part of Becherer, 1956, Florae Vallesiacae Supplementum, pp. 1-556 in Denkschriften der Schweizerischen Naturforschenden Gesellschaft 71 on pages 1-556
Pre-announcement of symbiotic guests: transcriptional reprogramming by mycorrhizal lipochitooligosaccharides shows a strict co-dependency on the GRAS transcription factors NSP1 and RAM1
Creators: name: Hohnjec, Natalija
name: Czaja-Hasse, Lisa F.
name: Hogekamp, Claudia
name: Kuster, Helge
Publisher: name: London : Biomed Central Ltd
Year: 2015
Subjects: subject: Arbuscular mycorrhiza
subject: GRAS transcription factor
subject: Lipochitooligosaccharide
subject: Medicago GeneChip
subject: NSP1
subject: Pre-symbiotic signaling
subject: RAM1
subject: Transcriptional reprogramming
subject: Dewey Decimal Classification::500 | Naturwissenschaften

description: BACKGROUND: More than 80 % of all terrestrial plant species establish an arbuscular mycorrhiza (AM) symbiosis with Glomeromycota fungi. This plant-microbe interaction primarily improves phosphate uptake, but also supports nitrogen, mineral, and water aquisition. During the pre-contact stage, the AM symbiosis is controled by an exchange of diffusible factors from either partner. Amongst others, fungal signals were identified as a mix of sulfated and non-sulfated lipochitooligosaccharides (LCOs), being structurally related to rhizobial nodulation (Nod)-factor LCOs that in legumes induce the formation of nitrogen-fixing root nodules. LCO signals are transduced via a common symbiotic signaling pathway (CSSP) that activates a group of GRAS transcription factors (TFs). Using complex gene expression fingerprints as molecular phenotypes, this study primarily intended to shed light on the importance of the GRAS TFs NSP1 and RAM1 for LCO-activated gene expression during pre-symbiotic signaling. RESULTS: We investigated the genome-wide transcriptional responses in 5 days old primary roots of the Medicago truncatula wild type and four symbiotic mutants to a 6 h challenge with LCO signals supplied at 10(-7/-8) M. We were able to show that during the pre-symbiotic stage, sulfated Myc-, non-sulfated Myc-, and Nod-LCO-activated gene expression almost exclusively depends on the LysM receptor kinase NFP and is largely controled by the CSSP, although responses independent of this pathway exist. Our results show that downstream of the CSSP, gene expression activation by Myc-LCOs supplied at 10(-7/-8) M strictly required both the GRAS transcription factors RAM1 and NSP1, whereas those genes either co- or specifically activated by Nod-LCOs displayed a preferential NSP1-dependency. RAM1, a central regulator of root colonization by AM fungi, controled genes activated by non-sulfated Myc-LCOs during the pre-symbiotic stage that are also up-regulated in areas with early physical contact, e.g. hyphopodia and infecting hyphae; linking responses to externally applied LCOs with early root colonization. CONCLUSIONS: Since both RAM1 and NSP1 were essential for the pre-symbiotic transcriptional reprogramming by Myc-LCOs, we propose that downstream of the CSSP, these GRAS transcription factors act synergistically in the transduction of those diffusible signals that pre-announce the presence of symbiotic fungi.
Mechanism of $K^- p \to ηΛ$ reaction near threshold
Creators: name: Liu, Bo-Chao
name: Xie, Ju-Jun
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: Nuclear Experiment (nucl-ex)
subject: FOS: Physical sciences

description: Within an effective Lagrangian approach, we investigate the reaction mechanism of $K^- p\to ηΛ$ near threshold. It is found that a new $D_{03}$ resonance, with mass $M=1668.5\pm 0.5$MeV and width $Γ=1.5\pm0.5$MeV, is needed to interpret the experimental data reported by the Crystal Ball collaboration. To verify our results, remeasurements on the differential cross sections and $Λ$ polarization in this reaction will be helpful. Furthermore, we also show that the reaction $p\bar p\to Λ\bar Λη$ is a good place to look for this new resonance if it exists.
description: Presented at the 20th International IUPAP Conference on Few-Body Problems in Physics, 20 - 25 August, 2012, Fukuoka, Japan
Levels of DNA methylation and transcript accumulation in leaves of transgenic maize varieties
Creators: name: Vilperte, Vinicius
name: Agapito-Tenfen, Sarah Zanon
name: Wikmark, Odd-Gunnar
name: Nodari, Rubens Onofre
Publisher: name: Heidelberg : Springer Verlag
Year: 2016
Subjects: subject: DNA methylation
subject: Epigenetics
subject: Genetic stability
subject: Genetically modified organism
subject: Risk assessment
subject: Stacked GMO
subject: Zea mays
subject: Figwort mosaic virus
subject: Dewey Decimal Classification::300 | Sozialwissenschaften, Soziologie, Anthropologie

description: Background: Prior to their release in the environment, transgenic crops are examined for their health and environmental safety. In addition, transgene expression needs to be consistent in order to express the introduced trait (e.g. insecticidal and/or herbicide tolerance). Moreover, data on expression levels for GM events are usually required for approval, but these are rarely disclosed or they are considered insufficient. On the other hand, biosafety regulators do not consider epigenetic regulation (e.g. DNA methylation, ncRNAs and histone modifications), which are broadly known to affect gene expression, within their risk assessment analyses. Here we report the results of a DNA methylation (bisulfite sequencing) and transgene transcript accumulation (RT-qPCR) analysis of four Bt-expressing single transgenic maize hybrids, under different genetic backgrounds, and a stacked transgenic hybrid expressing both insecticidal and herbicide tolerance traits. Results: Our results showed differences in cytosine methylation levels in the FMV promoter and cry2Ab2 transgene of the four Bt-expressing hybrid varieties. The comparison between single and stacked hybrids under the same genetic background showed differences in the 35S promoter sequence. The results of transgene transcript accumulation levels showed differences in both cry1A.105 and cry2Ab2 transgenes among the four Bt-expressing hybrid varieties. The comparison between single and stacked hybrids showed difference for the cry2Ab2 transgene only. Conclusions: Overall, our results show differences in DNA methylation patterns in all varieties, as well as in transgene transcript accumulation levels. Although the detection of changes in DNA methylation and transgenic accumulation levels does not present a safety issue per se, it demonstrates the need for additional studies that focus on detecting possible safety implications of such changes.
title: РАЗРАБОТКА МОДЕЛИ ПЕРЕДАЧИ ДАННЫХ В СЕТИ MANET НА ОСНОВЕ КИТАЙСКОЙ ТЕОРЕМЫ ОБ ОСТАТКАХ
title: DEVELOPING A MODEL OF DATA TRANSFER IN A MANET NETWORK BASED ON THE CHINESE REMAINTS THEOREM
Creators: name: Дерябин, М.А.
name: Кучуков, В.А.
name: Кучеров, Н.Н.
Publisher: name: ФГБНУ "Северо-Кавказский федеральный научный аграрный центр"
Year: 2019

description: В статье предложена схема передачи данных в сетях MANET построенная на пороговой схеме разделения секрета (СРС) обладающая вычислительной стойкость аналогичной СРС Асмут-Блум, однако скоростью кода у предложенной схемы разделения секрета в t раз больше. Предложенная СРС построенная на системе остаточных классов (СОК) позволяет обнаруживать ошибки в каналах связи используя аппарат кодов исправления ошибок на СОК. Из результатов моделирования можно сделать следующие выводы, что при сравнительно одинаковой занимаемой площади временная задержка приближенного метода при использовании модулей размерности до 64 бит на 20% меньше, а при использовании модулей размерности больше 64 бит задержка меньше на 30 % в сравнении с методом ортогональных базисов.В статье предложена схема передачи данных в сетях MANET построенная на пороговой схеме разделения секрета (СРС) обладающая вычислительной стойкость аналогичной СРС Асмут-Блум, однако скоростью кода у предложенной схемы разделения секрета в t раз больше. Предложенная СРС построенная на системе остаточных классов (СОК) позволяет обнаруживать ошибки в каналах связи используя аппарат кодов исправления ошибок на СОК. Из результатов моделирования можно сделать следующие выводы, что при сравнительно одинаковой занимаемой площади временная задержка приближенного метода при использовании модулей размерности до 64 бит на 20% меньше, а при использовании модулей размерности больше 64 бит задержка меньше на 30 % в сравнении с методом ортогональных базисов.
description: The article proposes a data transfer scheme in MANET networks built on a threshold secret sharing scheme (SSS) with computational strength similar to Asmut-Bloom SSS, however, the code speed of the proposed secret sharing scheme is t times greater. The proposed SSS built on the system of residual number system (RNS) allows you to detect errors in communication channels using the apparatus error correction codes on the RNS. From the simulation results we can draw the following conclusions: with a comparatively similar occupied area, the time delay of the approximate method when using modules of dimension up to 64 bits is 20% less, and when using modules of dimension more than 64 bits, the delay is 30% less compared to the method of orthogonal bases.
Pore-scale modeling of fluid-particles interaction and emerging poromechanical effects
Creators: name: Catalano, Emanuele
name: Chareyre, Bruno
name: Barthélémy, Eric
Publisher: name: arXiv
Year: 2013
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: A micro-hydromechanical model for granular materials is presented. It combines the discrete element method (DEM) for the modeling of the solid phase and a pore-scale finite volume (PFV) formulation for the flow of an incompressible pore fluid. The coupling equations are derived and contrasted against the equations of conventional poroelasticity. An analogy is found between the DEM-PFV coupling and Biot's theory in the limit case of incompressible phases. The simulation of an oedometer test validates the coupling scheme and demonstrates the ability of the model to capture strong poromechanical effects. A detailed analysis of microscale strain and stress confirms the analogy with poroelasticity. An immersed deposition problem is finally simulated and shows the potential of the method to handle phase transitions.
description: accepted in Int. Journal for Numerical and Analytical Methods in Geomechanics
Formation of circumbinary planets in a dead zone
Creators: name: Martin, Rebecca G.
name: Armitage, Philip J.
name: Alexander, Richard D.
Publisher: name: arXiv
Year: 2013
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Circumbinary planets have been observed at orbital radii where binary perturbations may have significant effects on the gas disk structure, on planetesimal velocity dispersion, and on the coupling between turbulence and planetesimals. Here, we note that the impact of all of these effects on planet formation is qualitatively altered if the circumbinary disk structure is layered, with a non-turbulent midplane layer (dead zone) and strongly turbulent surface layers. For close binaries, we find that the dead zone typically extends from a radius close to the inner disk edge up to a radius of around 10-20 au from the centre of mass of the binary. The peak in the surface density occurs within the dead zone, far from the inner disk edge, close to the snow line, and may act as a trap for aerodynamically coupled solids. We suggest that circumbinary planet formation may be easier near this preferential location than for disks around single stars. However, dead zones around wide binaries are less likely and hence planet formation may be more difficult there.
description: Accepted for publication in ApJ
Exploring Black Clinical Psychologists’ Experiences of Racism and its Discussion at Work and in the Profession.
Creators: name: Stoddart Isaac, Reay Cashel
Publisher: name: University of East London
Year: 2023
Subjects: Clinical Psychology
Racism
Whiteness

description: This research aimed to explore Black Clinical Psychologists’ (BCPs’) experiences of racism and its discussion at work and in the profession. Within this, there was a focus on how they describe and make sense of their experiences, how they feel they are positioned and perceived when racism is discussed, how they navigate conversations about racism and how they think a sense of safety and support could be fostered within these experiences. In line with the critical realist epistemological position, the methodology employed a qualitative design. Data was collected through twelve in-depth semi-structured interviews with clinical psychologists who self-identified as Black and practiced in the UK. Interviews were analysed using an inductive approach to reflexive thematic analysis. Five themes were identified: • “It is what I am”: BCP identity • Whiteness at work • Spotlighting Whiteness; the work of anti-racism • Resistance • “An absolute mess”; what needs to change These themes highlight and provide a narrative of the systemic and systematic processes of Whiteness and the ways in which it manifests in BCPs’ lived experiences. The analyses are discussed in relation to the research question and existing literature. Drawing upon the analyses, recommendations for clinical practice, policy, future research and education and training are made.
title: Οι περιβαλλοντικές επιπτώσεις του λιμενικού τομέα και η υιοθέτηση πράσινων πρακτικών στους λιμένες
title: The environmental impact of the port sector and the adoption of green practices in ports
titleType: AlternativeTitle
Creators: name: Στεφανόπουλος, Φώτιος
Publisher: name: Πανεπιστήμιο Πειραιώς
Year: 2023
Subjects: subject: Πράσινο λιμάνι
subject: Περιβάλλον
subject: Βιοποικιλότητα
subject: Βιώσιμη ανάπτυξη

description: Ο ναυτιλιακός τομέας διαδραματίζει καθοριστικό ρόλο στο παγκόσμιο εμπόριο, διευκολύνοντας τη διακίνηση αγαθών και προωθώντας την οικονομική ανάπτυξη. Ωστόσο, η ανάπτυξη αυτού του κλάδου έχει επιβαρυνθεί με σημαντικό περιβαλλοντικό κόστος, οδηγώντας σε διάφορες οικολογικές προκλήσεις. Η παρούσα εργασία εξετάζει διεξοδικά τις περιβαλλοντικές συνέπειες του ναυτιλιακού τομέα, με ιδιαίτερη έμφαση στα ελληνικά λιμάνια, ενώ παράλληλα διερευνά την υιοθέτηση πράσινων πρακτικών ως μέσο άμβλυνσης αυτών των επιπτώσεων. Η έρευνα ξεκινά με την παροχή μιας ολοκληρωμένης επισκόπησης της ναυτιλιακής βιομηχανίας, της ιστορικής της εξέλιξης και του ποικίλου φάσματος δραστηριοτήτων στις οποίες εμπλέκονται τα λιμάνια. Οι περιβαλλοντικές επιπτώσεις των ναυτιλιακών δραστηριοτήτων διερευνώνται διεξοδικά, διαφωτίζοντας ζητήματα όπως η ατμοσφαιρική ρύπανση, η ρύπανση των υδάτων και η μόλυνση του εδάφους. Η εργασία στην συνέχεια εισάγει την έννοια των πράσινων λιμένων ως βιώσιμη λύση σε αυτές τις περιβαλλοντικές προκλήσεις. Περιγράφει ένα ευρύτερο πλαίσιο λύσεων για την ανάπτυξη πράσινων λιμένων, εστιάζοντας σε βασικές αρχές και πολιτικές που περιλαμβάνουν μεταξύ άλλων την ενίσχυση της ενεργειακής απόδοσης, την ενσωμάτωση ανανεώσιμων πηγών ενέργειας, την προώθηση πράσινων αλυσίδων εφοδιασμού, καθώς και την εφαρμογή ολοκληρωμένων προγραμμάτων διαχείρισης αποβλήτων. Η εμπειρική αυτή ανάλυση εμβαθύνει στην τρέχουσα κατάσταση των πράσινων πρακτικών στα ελληνικά λιμάνια, με κύρια θέματα τον Πειραιά και τη Θεσσαλονίκη. Μια συγκριτική αξιολόγηση σε σχέση με κορυφαία ευρωπαϊκά λιμάνια αναδεικνύει τις διαφορές στην περιβαλλοντική δέσμευση, τονίζοντας τους τομείς στους οποίους τα ελληνικά λιμάνια έχουν περιθώρια βελτίωσης. Εν κατακλείδι, η έρευνα αυτή υπογραμμίζει την επείγουσα ανάγκη για τα ελληνικά λιμάνια να υιοθετήσουν πλήρως τις πράσινες πρακτικές. Καθώς η παγκόσμια κοινότητα εντείνει τις προσπάθειες για την καταπολέμηση της κλιματικής αλλαγής και την προστασία των οικοσυστημάτων, ο λιμενικός κλάδος καλείται να αναλάβει καθοριστικό ρόλο σε αυτή τη συλλογική προσπάθεια.
title: Προτάσεις ψηφιοποίησης μουσείου - Μελέτη περίπτωσης : το Αρχαιολογικό Μουσείο του Πειραιά
title: Museum digitalization proposals – Case study : Archaeological Museum of Piraeus
titleType: AlternativeTitle
Creators: name: Αβδέλαρου, Ελένη
name: Ζαχαριουδάκη, Μαρία
Publisher: name: Πανεπιστήμιο Πειραιώς
Year: 2023
Subjects: subject: Museum
subject: Digital
subject: Ψηφιοποίηση
subject: Φωτογραμμετρία
subject: Unity
subject: Sketch up
subject: 3d flow Zephyr

description: Τα μουσεία κατά το παρελθόν, μέχρι το παρόν και το μέλλον, διαδραματίζουν σπουδαίο ρόλο τόσο στην τέχνη, όσο και στην κοινωνία. Καθώς η τέχνη και η κοινωνία εξελίσσονται, αυτές οι αλλαγές πρέπει επίσης να αντικατοπτρίζονται στα μουσεία και στις δομές τους. Τα μουσεία αλληλοσυνδέονται με τον πολιτισμό, τον τουρισμό, την τεχνολογία, καθώς και την οικονομία. Στην παρούσα εργασία εξηγούνται οι έννοιες πολιτισμός και μουσείο, μέσα από μια βιβλιογραφική ανασκόπηση πραγματεύεται ο όρος «ψηφιακό μουσείο» και δίνονται παραδείγματα από την Ελλάδα του σήμερα. Ταυτόχρονα, πραγματεύεται ο ρόλος που διαδραματίζουν τα μέσα κοινωνικής δικτύωσης στην ανάπτυξη και ενίσχυση της πολιτισμικής παιδείας και των μουσείων καθώς και με ποια μέσα και εργαλεία μπορεί να επιτευχθεί η ψηφιοποίηση ενός μουσείου έχοντας σαν βασικό μας θέμα το Αρχαιολογικό Μουσείο του Πειραιά.
Mapping tissue inhomogeneity in acute myocarditis: a novel analytical approach to quantitative myocardial edema imaging by T2-mapping
Creators: name: Baessler, Bettina
name: Schaarschmidt, Frank
name: Dick, Anastasia
name: Stehning, Christian
name: Schnackenburg, Bernhard
name: Michels, Guido
name: Maintz, David
name: Bunck, Alexander C.
Publisher: name: London : Biomed Central Ltd
Year: 2015
Subjects: subject: Cardiovascular magnetic resonance
subject: Tissue characterization
subject: Acute myocarditis
subject: T2-mapping
subject: Myocardial edema
subject: Dewey Decimal Classification::500 | Naturwissenschaften

description: BACKGROUND: The purpose of the present study was to investigate the diagnostic value of T2-mapping in acute myocarditis (ACM) and to define cut-off values for edema detection. METHODS: Cardiovascular magnetic resonance (CMR) data of 31 patients with ACM were retrospectively analyzed. 30 healthy volunteers (HV) served as a control. Additionally to the routine CMR protocol, T2-mapping data were acquired at 1.5 T using a breathhold Gradient-Spin-Echo T2-mapping sequence in six short axis slices. T2-maps were segmented according to the 16-segments AHA-model and segmental T2 values as well as the segmental pixel-standard deviation (SD) were analyzed. RESULTS: Mean differences of global myocardial T2 or pixel-SD between HV and ACM patients were only small, lying in the normal range of HV. In contrast, variation of segmental T2 values and pixel-SD was much larger in ACM patients compared to HV. In random forests and multiple logistic regression analyses, the combination of the highest segmental T2 value within each patient (maxT2) and the mean absolute deviation (MAD) of log-transformed pixel-SD (madSD) over all 16 segments within each patient proved to be the best discriminators between HV and ACM patients with an AUC of 0.85 in ROC-analysis. In classification trees, a combined cut-off of 0.22 for madSD and of 68 ms for maxT2 resulted in 83% specificity and 81% sensitivity for detection of ACM. CONCLUSIONS: The proposed cut-off values for maxT2 and madSD in the setting of ACM allow edema detection with high sensitivity and specificity and therefore have the potential to overcome the hurdles of T2-mapping for its integration into clinical routine.
Kibble-Zurek mechanism in a trapped ferromagnetic Bose-Einstein condensate
Creators: name: Saito, Hiroki
name: Kawaguchi, Yuki
name: Ueda, Masahito
Publisher: name: arXiv
Year: 2013
Subjects: subject: Quantum Gases (cond-mat.quant-gas)
subject: FOS: Physical sciences

description: Spontaneous spin vortex formation in the magnetic phase transition of a trapped spin-1 Bose-Einstein condensate is investigated using mean-field theory. In a harmonic trapping potential, an inhomogeneous atomic density leads to spatial variations of the critical point, magnetization time scale, and spin correlation length. The Kibble-Zurek phenomena are shown to emerge even in such inhomogeneous systems, when the quench of the quadratic Zeeman energy is fast enough. For slow quench, the magnetized region gradually expands from the center of the trap pushing out spin vortices, which hinders the Kibble-Zurek mechanism from occurring. A harmonic trap with a plug potential is also taken into account.
description: 7 pages, 4 figures, 3 movies
More than just a metabolic regulator - elucidation and validation of new targets of PdhR in Escherichia coli
Creators: name: Göhler, Anna-Katharina
name: Kökpinar, Öznur
name: Schmidt-Heck, Wolfgang
name: Geffers, Robert
name: Guthke, Reinhard
name: Rinas, Ursula
name: Schuster, Stefan
name: Jahreis, Knut
name: Kaleta, Christoph
Publisher: name: London : BioMed Central Ltd.
Year: 2011
Subjects: subject: Escherichia coli
subject: Escherichia coli protein
subject: PdhR protein, E coli
subject: repressor protein
subject: article
subject: bacterial gene
subject: gene expression regulation
subject: gene regulatory network
subject: genetics
subject: metabolism
subject: methodology
subject: physiology
subject: regulon
subject: systems biology
subject: Escherichia coli Proteins
subject: Gene Expression Regulation, Bacterial
subject: Gene Regulatory Networks
subject: Genes, Bacterial
subject: Metabolic Networks and Pathways
subject: Regulon
subject: Repressor Proteins
subject: Systems Biology
subject: Dewey Decimal Classification::500 | Naturwissenschaften
subject: Dewey Decimal Classification::500 | Naturwissenschaften::570 | Biowissenschaften, Biologie

description: Background: The pyruvate dehydrogenase regulator protein (PdhR) of Escherichia coli acts as a transcriptional regulator in a pyruvate dependent manner to control central metabolic fluxes. However, the complete PdhR regulon has not yet been uncovered. To achieve an extended understanding of its gene regulatory network, we combined large-scale network inference and experimental verification of results obtained by a systems biology approach.Results: 22 new genes contained in two operons controlled by PdhR (previously only 20 regulatory targets in eight operons were known) were identified by analysing a large-scale dataset of E. coli from the Many Microbes Microarray Database and novel expression data from a pdhR knockout strain, as well as a PdhR overproducing strain. We identified a regulation of the glycolate utilization operon glcDEFGBA using chromatin immunoprecipitation and gel shift assays. We show that this regulation could be part of a cross-induction between genes necessary for acetate and pyruvate utilisation controlled through PdhR. Moreover, a link of PdhR regulation to the replication machinery of the cell via control of the transcription of the dcw-cluster was verified in experiments. This augments our knowledge of the functions of the PdhR-regulon and demonstrates its central importance for further cellular processes in E. coli.Conclusions: We extended the PdhR regulon by 22 new genes contained in two operons and validated the regulation of the glcDEFGBA operon for glycolate utilisation and the dcw-cluster for cell division proteins experimentally. Our results provide, for the first time, a plausible regulatory link between the nutritional status of the cell and cell replication mediated by PdhR.
title: Αποθέματα και προμήθειες στις δομές υγείας : διαχείριση αίματος
title: Inventory and procurement in healthcare : blood management
titleType: AlternativeTitle
Creators: name: Γιαννάτου, Μαρία
Publisher: name: Πανεπιστήμιο Πειραιώς
Year: 2023
Subjects: subject: Αποθέματα

description: Σκοπός της παρούσας έρευνας είναι να μελετήσουμε τους τρόπους και τα μέσα για την αποτελεσματική και ορθή διαχείριση αποθεμάτων, τα οποία συνάδουν ώστε να χρησιμοποιηθούν στις μονάδες και δομές υγείας. Τεχνικές και μοντέλα όπου χρησιμοποιούνται επί δεκαετίες στη διαχείριση αποθεμάτων, δε θα μπορούσαν να απέχουν και από ένα από τους μεγαλύτερους κλάδους όπως αυτός της Ιατροφαρμακευτικής. Οι δυσκολίες όπου αντιμετωπίζει αυτός ο κλάδος όμως είναι ιδιαίτερες, καθώς τα προϊόντα και τα αγαθά όπου καλείτε να διαχειριστεί είναι εξειδικευμένα. Πιο αναλυτικά, η διαχείριση των προϊόντων του αίματος αποτελεί μια πρόκληση τόσο για τις μονάδες υγείας, όσο και για ολόκληρο τον Παγκόσμιο Οργανισμό Υγείας. Η διαχείριση των αποθεμάτων αίματος και τα προβλήματα όπου εκρέει είναι πολλά. Οι πόροι που πρέπει να βρει παράγονται από μερικούς προμηθευτές παγκοσμίως και έχουν υψηλό κόστος, καθώς είναι προϊόντα εντάσεως κεφαλαίου, δαπανηρής έρευνας (R&D), υψηλής τεχνολογίας, εξειδικευμένων εφαρμογών κτλπ. Τέτοια είναι όλα τα ιατρικά μηχανήματα και τα φάρμακα και παράγονται από μεγάλες βιομηχανίες, οι οποίες πέρα ότι έχουν προϊόντα με τα παραπάνω χαρακτηριστικά, έχουν ολιγοπωλιακές τιμές, τις οποίες θα πρέπει να τις αντιμετωπίσουν οι δομές υγείας. Για το λόγο αυτό, τα τμήματα προμηθειών χρησιμοποιούν διάφορες τεχνικές, όπως βέλτιστης ποσότητας παραγγελίας και πρόβλεψης της ζήτησης, ώστε οι Δομές Υγείας να πετύχουν το βέλτιστο ελάχιστο κόστος. Ένα ακόμα κόστος, το οποίο θα πρέπει να λάβουν υπόψη τους είναι και αυτό των αποβλήτων τους, καθώς το νομικό πλαίσιο είναι αρκετά αυστηρό και θέτει σε ισχύ πολλά υποχρεωτικά μέτρα. Τα τμήματα προμηθειών στις μονάδες υγείας έχουν πολλά πράγματα να λάβουν υπόψη τους ς κατά τη διαχείριση απόβλήτων, για παράδειγμα αν θα γίνει εξωτερική ανάθεση (outsource) ή εσωτερική διαχείριση. Η αποτελεσματική διαχείριση του αίματος δεν μπορεί να γίνει από μια μονάδα υγείας, από μόνη της, αλλά συνολικά από όλες τις Δομές Υγείας. Εδώ ο Κρατικός φορέας και ειδικότερα τα υπουργεία Υγείας πρέπει να λάβουν διαφορετικές στρατηγικές για να πετύχουν αποτελεσματικά αποθέματα αίματος, σύμφωνα με γνώμονα το βαθμό κοινωνικής ευθύνης στο περιβάλλον τους. Η ενθάρρυνση των εθελοντών να προβούν σε αιμοληψίες και η σταθερή προσέλευση αιμοδοτών είναι κρίσιμη, αφού το αίμα δεν μπορεί να προέλθει ούτε από ζώα, αλλά ούτε και με κάποιο τεχνητό τρόπο. Αυτή η ενθάρρυνση επιτυγχάνεται με διάφορα κίνητρα, όπως για παράδειγμα χρηματικά κίνητρα.
title: ОБЗОР БЕЗОПАСНЫХ МЕТОДОВ ШИФРОВАНИЯ ДЛЯ ОБЛАЧНЫХ ВЫЧИСЛЕНИЙ
title: REVIEW OF SAFE ENCRYPTION METHODS FOR CLOUD CAL-CULATIONS
Creators: name: Дерябин, М.А.
name: Кучеров, Н.Н.
Publisher: name: ФГБНУ "Северо-Кавказский федеральный научный аграрный центр"
Year: 2019

description: Облачные вычисления приносят множество новых проблем для безопасности данных и управления доступом, когда пользователь передает конфиденциальные данные для обме-на, на облачных серверах которого находится не на доверенном домене, как владельца данных. Гомоморфное шифрование является одним из решений обеспечения безопасно-сти, которая позволяет проводить конкретные виды расчетов, которые будут проводиться над зашифрованными данными (текстами) и генерируют зашифрованный результат, кото-рый, когда при расшифровки будет соответствовать результату выполненных операций (выполняемых с текстом). Чтобы сохранить конфиденциальных данных от ненадежных серверов, криптографические методы используют раскрытие ключей расшифровки дан-ных только для авторизованных пользователей.
description: Cloud computing brings many new challenges to data security and access control when a user sends sensitive data for exchange, on cloud servers of which is not on a trusted domain, as the data owner. Homomorphic encryption is one of the security solutions that allow specific types of calculations to be performed on encrypted data (texts) and generate an encrypted result, which, when decrypted, will correspond to the result of the operations performed (performed with text). To preserve sensitive data from untrusted servers, cryptographic methods use data decryption keys disclosure only for authorized users.
Probing Non-Standard Interaction of Neutrinos with IceCube and DeepCore
Creators: name: Esmaili, Arman
name: Smirnov, Alexei Yu.
Publisher: name: arXiv
Year: 2013
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: High Energy Physics - Experiment (hep-ex)
subject: FOS: Physical sciences

description: We consider effects of the Non-Standard Interactions (NSI) on oscillations of the high energy atmospheric neutrinos. The ν_μ-oscillograms are constructed and their dependence on the NSI strength parameters ε_{αβ} studied. We computed zenith angle distributions of the ν_μ-events in the presence of NSI in different energy regions. The distributions are confronted with the IceCube-79 (high energy sample) and the DeepCore (low energy sample) data and constraints on the strength parameters |ε_{μτ}| < 6x10^-3 and |ε_{μμ}-ε_{ττ}| < 3x10^-2 (90% C.L.) have been obtained. Future measurements of the zenith angle distributions by DeepCore in smaller energy bins will allow to improve the bounds by factor 2 - 3. We discuss the signatures of NSI in zenith angle and energy distributions of events which allow to discriminate them from the effects of sterile neutrinos.
description: 30 pages, 15 figures; v2: Typos corrected, several comments added
Model-specific tests on variance heterogeneity for detection of potentially interacting genetic loci
Creators: name: Hothorn, Ludwig A.
name: Libiger, Ondrej
name: Gerhard, Daniel
Publisher: name: London : BioMed Central Ltd.
Year: 2012
Subjects: subject: Genetic association study
subject: Interaction
subject: Quantitative traits
subject: Variance heterogeneity
subject: article
subject: computer program
subject: gene locus
subject: genetic association
subject: genome
subject: genotype
subject: human
subject: quantitative trait
subject: single nucleotide polymorphism
subject: Alleles
subject: Analysis of Variance
subject: Blood Pressure
subject: Gene Frequency
subject: Genetic Heterogeneity
subject: Genome-Wide Association Study
subject: Genotype
subject: Heart Diseases
subject: Humans
subject: Models, Genetic
subject: Phenotype
subject: Polymorphism, Single Nucleotide
subject: Quantitative Trait Loci
subject: Software
subject: Waist Circumference
subject: Dewey Decimal Classification::500 | Naturwissenschaften
subject: Dewey Decimal Classification::500 | Naturwissenschaften::570 | Biowissenschaften, Biologie

description: Background: Trait variances among genotype groups at a locus are expected to differ in the presence of an interaction between this locus and another locus or environment. A simple maximum test on variance heterogeneity can thus be used to identify potentially interacting single nucleotide polymorphisms (SNPs).Results: We propose a multiple contrast test for variance heterogeneity that compares the mean of Levene residuals for each genotype group with their average as an alternative to a global Levene test. We applied this test to a Bogalusa Heart Study dataset to screen for potentially interacting SNPs across the whole genome that influence a number of quantitative traits. A user-friendly implementation of this method is available in the R statistical software package multcomp.Conclusions: We show that the proposed multiple contrast test of model-specific variance heterogeneity can be used to test for potential interactions between SNPs and unknown alleles, loci or covariates and provide valuable additional information compared with traditional tests. Although the test is statistically valid for severely unbalanced designs, care is needed in interpreting the results at loci with low allele frequencies.