cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
On the origin of the controversial electrostatic field effect in superconductors
Creators: name: Golokolenov, Ilia
name: Guthrie, Andrew
name: Kafanov, Sergey
name: Pashkin, Yuri
name: Tsepelin, Viktor
Publisher: name: arXiv
Year: 2020
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: In semiconductor electronics, the field-effect refers to the control of electrical conductivity in nanoscale devices, which underpins the field-effect transistor, one of the cornerstones of present-day semiconductor technology. The effect is enabled by the penetration of the electric field far into a weakly doped semiconductor, whose charge density is not sufficient to screen the field. On the contrary, the charge density in metals and superconductors is so large that the field decays exponentially from the surface and can penetrate only a short distance into the material. Hence, the field-effect should not exist in such materials. Nonetheless, recent publications have reported observation of the field-effect in superconductors and proximised normal metal nanodevices. The effect was discovered in gated nanoscale superconducting constrictions as a suppression of the critical current under the application of intense electric field and interpreted in terms of an electric-field induced perturbation propagating inside the superconducting film. Here we show that ours, and previously reported observations, governed by the overheating of the constriction, without recourse to novel physics. The origin of the overheating is a leakage current between the gate and the constriction, which perfectly follows the Fowler-Nordheim model of electron field emission from a metal electrode.c`
description: 6 pages, 4 figures
Controlling crystallization and its absence: Proteins, colloids and patchy models
Creators: name: Doye, Jonathan P. K.
name: Louis, Ard A.
name: Lin, I-Chun
name: Allen, Lucy R.
name: Noya, Eva G.
name: Wilber, Alex W.
name: Kok, Hoong Chwan
name: Lyus, Rosie
Publisher: name: arXiv
Year: 2007
Subjects: subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The ability to control the crystallization behaviour (including its absence) of particles, be they biomolecules such as globular proteins, inorganic colloids, nanoparticles, or metal atoms in an alloy, is of both fundamental and technological importance. Much can be learnt from the exquisite control that biological systems exert over the behaviour of proteins, where protein crystallization and aggregation are generally suppressed, but where in particular instances complex crystalline assemblies can be formed that have a functional purpose. We also explore the insights that can be obtained from computational modelling, focussing on the subtle interplay between the interparticle interactions, the preferred local order and the resulting crystallization kinetics. In particular, we highlight the role played by ``frustration'', where there is an incompatibility between the preferred local order and the global crystalline order, using examples from atomic glass formers and model anisotropic particles.
description: 11 pages, 7 figures
Guaranteed $ε$-optimal solutions with the linear optimizer ART3+O
Creators: name: Gorissen, Bram L.
Publisher: name: arXiv
Year: 2021
Subjects: subject: Medical Physics (physics.med-ph)
subject: FOS: Physical sciences

description: The linear optimization algorithm ART3+O introduced by Chen et al. (2010) can efficiently solve large scale inverse planning problems encountered in radiation therapy by iterative projection. Its major weakness is that it cannot guarantee $ε$-optimality of the final solution due to an arbitrary stopping criterion. We propose an improvement to ART3+O where the stopping criterion is based on Farkas' lemma. The same theory can be used to detect inconsistency in other projection methods as well. The proposed algorithm guarantees to find an $ε$-optimal solution in finite time. The algorithm is demonstrated on numerical examples in radiation therapy.
H$α$ long term monitoring of the Be star $β$ Cep Aa
Creators: name: Catanzaro, G.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: Recent papers published in the last years contributed to resolve the enigma on the hypothetical Be nature of the hot pulsating star $β$ Cep. This star shows variable emission in the H$α$ line, typical for Be stars, but its projected rotational velocity is very much lower than the critical limit, contrary to what is expected for a typical Be star. The emission has been attributed to the secondary component of the $β$ Cep spectroscopic binary system. In this paper, using both ours and archived spectra, we attempted to recover the H$α$ profile of the secondary component and to analyze its behavior with time for a long period. To accomplish this task, we first derived the atmospheric parameters of the primary: T$_{\rm eff}$ = 24000 $\pm$ 250 K and $\log g$ = 3.91 $\pm$ 0.10, then we used these values to compute its synthetic H$α$ profile and finally we reconstructed the secondary's profile disentangling the observed one. The secondary's H$α$ profile shows the typical two peaks emission of a Be star with a strong variability. We analyzed also the behavior versus time of some line width parameters: equivalent width, V/R, FWHM, peaks separation and radial velocity of the central depression. Projected rotational velocity ($v \sin i$) of the secondary and the dimension of the equatorial surrounding disk have been estimated, too.
description: 9 pages, 6 figures, 2 tables, accepted for publication in MNRAS
Αντιλήψεις μαθητών (5 έως 7 χρονών) για τη θρέψη και την ανάπτυξη των φυτών
Creators: name: Χατζηνικήτα, Βασιλεία
name: Κουλαϊδής, Βασίλης
name: Ζόγκα, Βασιλική
Publisher: name: Παιδαγωγική Επιθεώρηση
Year: 1999

description: Photosynthesis, respiration, nutrition and growth are some of the fundamental issues of plant physiology. For this reason these issues constitute part of the curriculum in the pri¬mary and secondary education. Nevertheless, teaching and learning these phenomena present various difficulties. This is evident from a review of the recent bibliography, as this is an increased interest of the researchers for the different sides of this thematic area (biochemical, ecological, physiological). This paper aims at analyzing the views and obstacles that pre-school and early children primary |5 - 7 years of age have when trying to understand the nutrition and growth of plants. Specifically children ideas concerning the following aspects the nutrition and growth processes are investigated a) The plants as food producers, b) The substances necessary for the plant nutrition and the role they play in nutrition, c) The plant s parts through which the absorption of the essential nutrients, d) The characteristics of the growth procedure of the plants (intake or no-intake of the essences from the immediate environment, naturalistic of no naturalistic character of the growth procedure)
description: Παιδαγωγική Επιθεώρηση, Vol. 29 (1999)
Synchronizing subgrid scale models of turbulence to data
Creators: name: Buzzicotti, M.
name: Di Leoni, P. Clark
Publisher: name: arXiv
Year: 2020
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: FOS: Physical sciences

description: Large Eddy Simulations of turbulent flows are powerful tools used in many engineering and geophysical settings. Choosing the right value of the free parameters for their subgrid scale models is a crucial task for which the current methods present several shortcomings. Using a technique called nudging we show that Large Eddy Simulations can synchronize to data coming from a high-resolution direct numerical simulation of homogeneous and isotropic turbulence. Furthermore, we found that the degree of synchronization is dependent on the value of the parameters of the subgrid scale models utilized, suggesting that nudging can be used as a way to select the best parameters for a model. For example, we show that for the Smagorinsky model synchronization is optimal when its constant takes the usual value of $0.16$. Analyzing synchronization dynamics puts the focus on reconstructing trajectories in phase space, contrary to traditional a posteriori tests of Large Eddy Simulations where the statistics of the flows are compared. These results open up the possibility of utilizing non-statistical analysis in a posteriori tests of Large Eddy Simulations.
Color Screening, Casimir Scaling, and Domain Structure in G(2) and SU(N) Gauge Theories
Creators: name: Greensite, J.
name: Langfeld, K.
name: Olejnik, S.
name: Reinhardt, H.
name: Tok, T.
Publisher: name: arXiv
Year: 2006
Subjects: subject: High Energy Physics - Lattice (hep-lat)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We argue that screening of higher-representation color charges by gluons implies a domain structure in the vacuum state of non-abelian gauge theories, with the color magnetic flux in each domain quantized in units corresponding to the gauge group center. Casimir scaling of string tensions at intermediate distances results from random spatial variations in the color magnetic flux within each domain. The exceptional G(2) gauge group is an example rather than an exception to this picture, although for G(2) there is only one type of vacuum domain, corresponding to the single element of the gauge group center. We present some numerical results for G(2) intermediate string tensions and Polyakov lines, as well as results for certain gauge-dependent projected quantities. In this context, we discuss critically the idea of projecting link variables to a subgroup of the gauge group. It is argued that such projections are useful only when the representation-dependence of the string tension, at some distance scale, is given by the representation of the subgroup.
description: 24 pages, 14 figures; v2: references added; v3: published version containing some additional introductory discussion
Comment on `Linear energy transfer incorporated intensity modulated proton therapy optimization'
Creators: name: Gorissen, Bram L
Publisher: name: arXiv
Year: 2021
Subjects: subject: Medical Physics (physics.med-ph)
subject: FOS: Physical sciences

description: Cao et al (2018) published an article on inverse planning based on dose-averaged linear energy transfer (LET). Their claim that the problem can be cast as a linear optimization model relies on an incorrect application of the Charnes-Cooper transformation. In this comment we show that their linear model is simlar to one where dose-averaged LET is multiplied with dose, explaining why their model was nonetheless able to improve the LET distribution.
Generating green to red light with semiconductor lasers
Creators: name: Ferrari, Gabriele
Publisher: name: arXiv
Year: 2007
Subjects: subject: Optics (physics.optics)
subject: Instrumentation and Detectors (physics.ins-det)
subject: FOS: Physical sciences

description: Diode lasers enable one to continuously cover the 730 to 1100 nm range as well as the 370 to 550 nm range by frequency doubling, but a large part of the electro-magnetic spectrum spanning from green to red remains accessible only through expensive and unpractical optically pumped dye lasers. Here we devise a method to multiply the frequency of optical waves by a factor 3/2 with a conversion that is phase-coherent and highly efficient. Together with harmonic generation, it will enable one to cover the visible spectrum with semiconductor lasers, opening new avenues in important fields such as laser spectroscopy and optical metrology.
description: to be published on Optics Express
Τα βιντεοπαιχνίδια στην καθημερινή ζωή των παιδιών
Creators: name: Τσιτουρίδου, Μ.
name: Βρύζας, Κ.
name: Σεμεντεριάδης, Θ.
Publisher: name: Παιδαγωγική Επιθεώρηση
Year: 1999

description: The purpose of this study is to investigate how video games are used and why children choose to play them. The research was based on a random sample of 255 schoolchildren from two age-groups, 11-12 and 14-15. The results of this study bring forward the extensive use of video games which become in integral part of a child's environment, particularly for boys. The two categories of video games for which children show a preference are games of action and adventure - fun-tasty. In video games children seek pleasure and entertainment, escape into an imaginary world, and relaxation, as well as active participation and the sense of superiority that derives from attaining their objective.
description: Παιδαγωγική Επιθεώρηση, Vol. 29 (1999)
Oxygen depletion in FLASH ultra-high-dose-rate radiotherapy: A molecular dynamics simulation
Creators: name: Abolfath, Ramin
name: Grosshans, David
name: Mohan, Radhe
Publisher: name: arXiv
Year: 2020
Subjects: subject: Medical Physics (physics.med-ph)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Biological Physics (physics.bio-ph)
subject: Chemical Physics (physics.chem-ph)
subject: Computational Physics (physics.comp-ph)
subject: FOS: Physical sciences

description: We present a first-principles molecular dynamics (MD) simulation and expound upon a mechanism of oxygen depletion hypothesis to explain the mitigation of normal tissue injury observed in ultra-high-dose-rate (UHDR) FLASH radiotherapy. We simulated damage to a segment of DNA (also representing other bio-molecules such as RNA and proteins) in a simulation box filled with H$_2$O and O$_2$ molecules. Attoseconds physical interactions (ionizations, electronic and vibrational excitations) were simulated by using the Monte Carlo track structure code Geant4-DNA. Immediately after ionization, {\it ab initio} Car-Parrinello molecular dynamics (CPMD) simulation was used to identify which H$_2$O and O$_2$ molecules surrounding the DNA-molecule were converted into reactive oxygen species (ROS). Subsequently, the femto- to nano-second reactions of ROS were simulated by using MD with Reactive Force Field (ReaxFF), to illustrate ROS merging into new types of non-reactive oxygen species (NROS) due to strong coupling among ROS. Time-dependent molecular simulations revealed the formation of metastable and transient spaghetti-like complexes among ROS generated at UHDR. At the higher ROS densities produced under UHDR, stranded chains (i.e., NROS) are produced, mediated through attractive electric polarity forces, hydrogen bonds, and magnetic dipole-dipole interactions among hydroxyl (\ce{^{.}OH}) radicals. NROS tend to be less mobile than cellular biomolecules as opposed to the isolated and sparsely dense ROS generated at conventional dose rates (CDR). We attribute this effect to the suppression of bio-molecular damage induced per particle track. At a given oxygen level, as the dose rate increases, the size and number of NROS chains increase, and correspondingly the population of toxic ROS components decreases.
Hurst Exponents, Markov Processes, and Fractional Brownian motion
Creators: name: McCauley, Joseph L.
name: Gunaratne, Gemunu H.
name: Bassler, Kevin E.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: There is much confusion in the literature over Hurst exponents. Recently, we took a step in the direction of eliminating some of the confusion. One purpose of this paper is to illustrate the difference between fBm on the one hand and Gaussian Markov processes where H not equal to 1/2 on the other. The difference lies in the increments, which are stationary and correlated in one case and nonstationary and uncorrelated in the other. The two- and one-point densities of fBm are constructed explicitly. The two-point density doesn't scale. The one-point density is identical with that for a Markov process with H not 1/2. We conclude that both Hurst exponents and histograms for one point densities are inadequate for deducing an underlying stochastic dynamical system from empirical data.
Tunable Majorana corner modes in noncentrosymmetric superconductors: Tunneling spectroscopy and edge imperfections
Creators: name: Ikegaya, S.
name: Rui, W. B.
name: Manske, D.
name: Schnyder, Andreas P.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: Majorana corner modes appearing in two-dimensional second-order topological superconductors have great potential applications for fault-tolerant topological quantum computations. We demonstrate that in the presence of an in-plane magentic field two-dimensional ($s+p$)-wave superconductors host Majorana corner modes, whose location can be manipulated by the direction of the magnetic field. In addition, we discuss the effects of edge imperfections on the Majorana corner modes. We describe how different edge shapes and edge disorder affect the number and controllability of the Majorana corner modes, which is of relevance for the implementation of topological quantum computations. We also discuss tunneling spectroscopy in the presence of the Majorana corner modes, where a lead-wire is attached to the corner of the noncentrosymmetric superconductor. The zero-bias differential conductance shows a distinct periodicity with respect to the direction of the magnetic field, which demonstrates the excellent controllability of the Majorana corner modes in this setup. Our results lay down the theoretical groundwork for observing and tuning Majoran corner modes in experiments on ($s+p$)-wave superconductors.
description: 11 pages, 10 figures
What M dwarf models reveal about their UV spectra?
Creators: name: Tilipman, Dennis
name: Vieytes, Mariela
name: Linsky, Jeffrey L.
Publisher: name: Zenodo
Year: 2021
Subjects: Cool Stars on the main sequence

description: Stellar ultraviolet (UV) radiation has significant implications on habitability of their exoplanets, yet this radiation is partly unobservable due to interstellar medium absorption. We used the radiative transfer code SSRPM to build stellar models of two M dwarfs and synthesize their UV spectra, particularly focusing on the far-UV and extreme-UV spectra. Our most important findings are that 1) the coronae of two M dwarfs are responsible for more than half of their respective EUV fluxes, and 2) the continuum in the FUV band between 145 and 170 nm is responsible for about half of total emission in this band. Here, we discuss the significance of these results and outline future projects aimed to improve our understanding of solar and stellar UV emission.
A revision of the vdB 130 cluster stellar content based on GAIA DR2 Data. Interstellar extinction toward the Cyg OB1 supershell
Creators: name: Sitnik, T. G.
name: Rastorguev, A. S.
name: Tatarnikova, A. A.
name: Tatarnikov, A. M.
name: Egorov, O. V.
name: Tatarnikov, A. A.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: Two star-forming regions are studied: the young embedded open cluster vdB 130 and the protocluster neighbourhood observed in the head and tail of the cometary molecular cloud located in the wall of the expanding supershell surrounding the Cyg OB1 association. The GAIA DR2 catalogue is employed to verify the stellar composition of the vdB 130 cluster whose members were earlier selected using the UCAC4 catalogue. The new sample of vdB 130 members contains 68 stars with close proper motions (within 1 mas yr$^{-1}$) and close trigonometric parallaxes (ranging from 0.50 to 0.70 mas). The relative parallax error is shown to increase with distance to objects and depend on their magnitude. At a distance of 1.5-2 kpc it is of about 3-7 per cent and 20-30 per cent for bright and faint stars, respectively. The cluster is not older than ~10 Myr. New spectroscopic and photometric observations carried out on Russian telescopes are combined with GAIA DR2 to search for optical components in the protocluster region - a new starburst. An analysis of 20 stars in the vicinity of the protocluster revealed no concentration of either proper motions or parallaxes. According to spectroscopic, photometric, and trigonometric estimates, the distances to these stars range from 0.4 to 2.5 kpc, and colour excess is shown to increase with a distance D (kpc) in accordance with the law: $E(B-V)\simeq 0.6\times D$ mag.
description: 14 pages, 11 figures, 5 tables; accepted for publication in MNRAS
Universal optimality of Patterson's crossover designs
Creators: name: Shah, Kirti R.
name: Bose, Mausumi
name: Raghavarao, Damaraju
Publisher: name: arXiv
Year: 2006
Subjects: subject: Statistics Theory (math.ST)
subject: FOS: Mathematics
subject: 62K05 (Primary) 62K10 (Secondary)

description: We show that the balanced crossover designs given by Patterson [Biometrika 39 (1952) 32--48] are (a) universally optimal (UO) for the joint estimation of direct and residual effects when the competing class is the class of connected binary designs and (b) UO for the estimation of direct (residual) effects when the competing class of designs is the class of connected designs (which includes the connected binary designs) in which no treatment is given to the same subject in consecutive periods. In both results, the formulation of UO is as given by Shah and Sinha [Unpublished manuscript (2002)]. Further, we introduce a functional of practical interest, involving both direct and residual effects, and establish (c) optimality of Patterson's designs with respect to this functional when the class of competing designs is as in (b) above.
description: Published at http://dx.doi.org/10.1214/009053605000000723 in the Annals of Statistics (http://www.imstat.org/aos/) by the Institute of Mathematical Statistics (http://www.imstat.org)
Importance of visit type in understanding results from phenome-wide association studies: results from a Visit-WAS
Creators: name: Boland, Mary Regina
name: Snigdha  Alur-Gupta
name: Levine, Lisa
name: Gabriel, Peter
name: Gonzalez-Hernandez, Graciela
Publisher: name: F1000 Research Limited
Year: 2019

description: Introduction: Widespread adoption of Electronic Health Records (EHR) increased the number of reported disease association studies, or Phenome-Wide Association Studies (PheWAS). Traditional PheWAS studies ignore visit type (i.e., department/service conducting the visit). In this study, we investigate the role of visit type on disease association results in the first Visit-Wide Association Study or ‘VisitWAS’.
Results: We studied this visit type effect on association results using EHR data from the University of Pennsylvania. Penn EHR data comes from 1,048 different departments and clinics. We analyzed differences between cancer and obstetrics/gynecologist (Ob/Gyn) visits. Some findings were expected (i.e., increase of neoplasm diagnoses among cancer visits), but others were surprising, including an increase in infectious disease conditions among those visiting the Ob/Gyn.
Conclusion: We conclude that assessing visit type is important for EHR studies because different medical centers have different visit type distributions. To increase reproducibility among EHR data mining algorithms, we recommend that researchers report visit type in studies.
Συγκλίσεις και αποκλίσεις στις απόψεις ανδρών και γυναικών εκπαιδευτικών για τη διδασκαλία και μάθηση των Φυσικών Επιστημών στο Δημοτικό σχολείο
Creators: name: Σταυρίδου, Ελένη
name: Σολομωνίδου, Χριστίνα
name: Σαχινίδου, Νικολλέτα
Publisher: name: Παιδαγωγική Επιθεώρηση
Year: 1999

description: This paper aims at presenting and commenting some of the most characteristic results of empirical research held in the District of Magnesia among primary school teachers. The instrument used was a questionnaire and the samples received were totally 274 in number, of which 123 male teachers and 151 female ones accordingly. The teachers were asked 1o express their views concerning the fact that it is mainly female teachers who teach in the first three grades of the primary school, whereas for the last two grades male teachers mainly undertake this task. They were then asked to express their beliefs concerning the question of differentiation or not in the effectiveness of teaching/learning Science in the primary school and its relation or not to the teachers' and students' sex. The results of this study showed many similarities, but also a lot of differences in the views of male and female teachers. Finally, suggestions are made towards interventions as concerns this aspect of education aiming at providing equal opportunities alike to boys and girls in Science and Technology Education.
description: Παιδαγωγική Επιθεώρηση, Vol. 29 (1999)
Evolution of resilience in protein interactomes across the tree of life
Creators: name: Zitnik, Marinka
name: Sosic, Rok
name: Feldman, Marcus
name: Leskovec, Jure
Publisher: name: F1000 Research Limited
Year: 2019

description: Phenotype robustness to environmental fluctuations is a common biological phenomenon. Although most phenotypes involve multiple proteins that interact with each other, the basic principles of how such interactome networks respond to environmental unpredictability and change during evolution are largely unknown. Here we study interactomes of 1,840 species across the tree of life involving a total of 8,762,166 protein-protein interactions. Our study focuses on the resilience of interactomes to network failures and finds that interactomes become more resilient during evolution, meaning that interactomes become more robust to network failures over time. In bacteria, we find that a more resilient interactome is in turn associated with the greater ability of the organism to survive in a more complex, variable, and competitive environment. We find that at the protein family level proteins exhibit a coordinated rewiring of interactions over time and that a resilient interactome arises through the gradual change of the network topology. Our findings have implications for understanding the molecular network structure in the context of both evolution and environment.
The ExoMolOP Database: Cross-sections and k-tables for Molecules of Interest in High-Temperature Exoplanet Atmospheres
Creators: name: Chubb, Katy L.
name: Rocchetto, Marco
name: Yurchenko, Sergei N.
name: Min, Michiel
name: Waldmann, Ingo
name: Barstow, Joanna K.
name: Mollière, Paul
name: Al-Refaie, Ahmed F.
name: Phillips, Mark W.
name: Tennyson, Jonathan
Publisher: name: arXiv
Year: 2020
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: FOS: Physical sciences

description: A publicly available database of opacities for molecules of astrophysical interest, ExoMolOP, has been compiled for over 80 species, based on the latest line list data from the ExoMol, HITEMP and MoLLIST databases. These data are generally suitable for characterising high temperature exoplanet or cool stellar/substellar atmospheres, and have been computed at a variety of pressures and temperatures, with a few molecules included at room-temperature only from the HITRAN database. The data are formatted in different ways for four different exoplanet atmosphere retrieval codes; ARCiS, TauREx, NEMESIS and petitRADTRANS, and include both cross-sections (at R~=~$\fracλ{Δλ}$~=~15,000) and k-tables (at R~=~$\fracλ{Δλ}$~=~1000) for the 0.3~-~50$μ$m wavelength region. Opacity files can be downloaded and used directly for these codes. Atomic data for alkali metals Na and K are also included, using data from the NIST database and the latest line shapes for the resonance lines. Broadening parameters have been taken from the literature where available, or from those for a known molecule with similar molecular properties where no broadening data are available. The data are available from www.exomol.com.
description: 25 pages, 9 figures. Accepted for publication in A&A
A scalable Computer-Aided Detection system for microcalcification cluster identification in a pan-European distributed database of mammograms
Creators: name: Retico, A.
name: Delogu, P.
name: Fantacci, M. E.
name: Martinez, A. Preite
name: Stefanini, A.
name: Tata, A.
Publisher: name: arXiv
Year: 2007
Subjects: subject: Medical Physics (physics.med-ph)
subject: FOS: Physical sciences

description: A computer-aided detection (CADe) system for microcalcification cluster identification in mammograms has been developed in the framework of the EU-founded MammoGrid project. The CADe software is mainly based on wavelet transforms and artificial neural networks. It is able to identify microcalcifications in different kinds of mammograms (i.e. acquired with different machines and settings, digitized with different pitch and bit depth or direct digital ones). The CADe can be remotely run from GRID-connected acquisition and annotation stations, supporting clinicians from geographically distant locations in the interpretation of mammographic data. We report the FROC analyses of the CADe system performances on three different dataset of mammograms, i.e. images of the CALMA INFN-founded database collected in the Italian National screening program, the MIAS database and the so-far collected MammoGrid images. The sensitivity values of 88% at a rate of 2.15 false positive findings per image (FP/im), 88% with 2.18 FP/im and 87% with 5.7 FP/im have been obtained on the CALMA, MIAS and MammoGrid database respectively.
description: 6 pages, 5 figures; Proceedings of the ITBS 2005, 3rd International Conference on Imaging Technologies in Biomedical Sciences, 25-28 September 2005, Milos Island, Greece
Vodmath – Υποστήριξη εκμάθησης μαθηματικών με χρήση Vodcast/Screencast
Creators: name: Χριστοδούλου, Γεώργιος Αναστασίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: subject: Μαθηματικά
subject: Eξ αποστάσεως μάθηση
subject: Καταγραφή οθόνης
subject: Mathematics
subject: FOS: Mathematics
subject: E-learning
subject: Screencast

description: Η παρούσα εργασία ασχολείται με τη δημιουργία μιας ιστοσελίδας στην οποία ένας καθηγητής μαθηματικών μπορεί να αναρτά εκπαιδευτικά βιντεομαθήματα (screencasts/vodcasts). Οι χρήστες – μαθητές μπορούν να περιηγούνται ελεύθερα στην ιστοσελίδα, να παρακολουθούν τα βιντεομαθήματα και σε συνδυασμό με την παραδοσιακή μέθοδο διδασκαλίας εντός σχολικής αίθουσας να μπορούν να καλύψουν τυχόντα μαθησιακά κενά, εισάγωντάς τους έναν καινούριο τρόπο εκμάθησης μαθηματικών. Με το πέρας του προγράμματος, δόθηκε στους χρήστες (μαθητές Α΄και Β΄Λυκείου) ένα ερωτηματολόγιο (post test) με σκοπό τη διερεύνηση της στάσης των μαθητών απέναντι στο μάθημα των μαθηματικών, την αξιολόγηση της ευχρηστίας της ψηφιακής πλατφόρμας και τέλος τη διερεύνηση της στάσης των μαθητών ανάλογα με την τροπικότητα των videos. Η αξιολόγηση έγινε βάση των απαντήσεων που έδωσαν στα ερωτηματολόγια 105 χρήστες στις οποίες πραγματοποιήθηκε η στατιστική ανάλυση των αποτελεσμάτων μέσω του SPSS.
description: Τhis project was designed with a view to provide a website on which a mathematics tutor can post educational videos (vodcasts/screencasts). Students can navigate freely within the webpage, watch the videos and in combination with the traditional method of tutoring within the school bounds, can cover any learning gaps using this new approach of learning mathematics. After the conclusion of the project, the users (students of A and B class of greek lyceum equivalent to 10th and 11th grade of the American educational system) were given a post test in order to investigate their disposition towards mathematics, evaluate the usability of the digital platform and finally to discover their preference in reference to the modality of the videos. The evaluation was done based on the answers of 105 users to the questionnaires, which were then statistically analyzed via SPSS.
Ab initio prediction of half-metallic properties for the ferromagnetic Heusler alloys Co$_2$MSi (M=Ti, V, Cr)
Creators: name: Chen, Xing-Qiu
name: Podloucky, R.
name: Rogl, P.
Publisher: name: arXiv
Year: 2006
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: By means of density functional calculations the magnetic and electronic properties and phase stabilities of the Heusler compounds Co$_2$MSi (with M=Ti, V, Cr, Mn, Fe, Co, Ni) were investigated. Based on the calculated results we predict the ferromagnetic phases of the compounds Co$_2$TiSi, Co$_2$VSi and Co$_2$CrSi to be half-metals. Of particular interest is Co$_2$CrSi because of its high density of majority spin states at Fermi energy in combination with a reasonably high estimated Curie temperature of 747K. The compounds Co$_2$TiSi and Co$_2$VSi are thermodynamically stable, whereas Co$_2$CrSi is a metastable phase which might be stabilized by suitable experimental techniques.
description: J. Appl. Phys. (in press), 2006
Διαπραγματευτικό μοντέλο πολίτη με εφορία με χρήση ευφυών πρακτόρων
Creators: name: Παλαιοδήμος, Κωνσταντίνος Αναστασίου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Διαπραγματευτικό μοντέλο
ευφυείς
πράκτορες
Negotiating model
intelligent
agents

description: Στην εργασία αυτή επιχειρούμε μέσα από την θεωρητική ανάλυση και πραγμάτευση ενός συγκεκριμένου διαπραγματευτικού ζητήματος να προσεγγίσουμε ορισμένες λύσεις οι οποίες είναι σαφείς και καλώς ορισμένες. Το ζήτημα που πραγματευόμαστε σε θεωρητικό επίπεδο είναι αυτό της διαπραγμάτευσης πολιτών που αναπαρίστανται ως αυτόνομοι πράκτορες όπως αυτοί εννοούνται μέσα στην οικονομική επιστήμη και ειδικότερα στην θεωρία παιγνίων. Αναλύονται όλες οι έννοιες οι οποίες κρίνονται απαραίτητες για την σε βάθος κατανόηση του προβλήματος. Οι έννοιες αυτές είτε ρητά μας απασχολούν είτε υπολανθάνουν στην μοντελοποίηση που υλοποιείται αμέσως μετά, συνιστούν όμως το αναγκαίο υπόβαθρο για την ευχερή και γόνιμη παρακολούθηση της μοντελοποίησης αυτής που επιτελείται. Έπειτα από την θεωρητική πραγμάτευση, γίνεται προσπάθεια εύρεσης και ανάδειξης του καταλληλότερου πακέτου, ώστε να εφαρμοστούν οι θεωρητικές αυτές ιδέες στο καταλληλότερο δυνατό περιβάλλον για θεωρία παιγνίων. Το περιβάλλον αυτό καταδεικνύεται πως είναι το Gambit 13, του οποίου την υπολογιστική ισχύ αξιοποιούμε σε μεγάλο βαθμό κατασκευάζοντας ένα μεσαίας έως μεγάλης έκτασης και εκτεταμένης μορφής παίγνιο που αναπαριστά την διαπραγμάτευση που γίνεται. Μέσα από την εύρεση των λύσεων των σημείων ισορροπίας Nash, καταλήγουμε σε ορισμένα συμπεράσματα τα οποία, ανάγοντάς μας από το ειδικότερο στο γενικότερο, μας δίνουν μια διαυγή εικόνα του προβλήματός μας, καθώς και των ντετερμινιστικών στοιχείων και περιορισμών που υπεισέρχονται στην συγκεκριμένη μοντελοποίησή του. Στην καθαυτό μοντελοποίηση, αν και γίνεται αναφορά σε άλλες μεθοδολογίες, θεωρούμε πως έχουμε τέλεια πληροφόρηση, ενώ όλα τα ζητήματα συζητούνται και τίθενται ταυτοχρόνως. Εκεί, λοιπόν, ξεκινάμε με ένα χρονικό περιορισμό και κατόπιν εισάγουμε ένα δεύτερο. Τα αποτελέσματα δείχνεται πως, τουλάχιστον στην συγκεκριμένη περίπτωση, δεν διαφοροποιούνται, αλλά αποδεικνύεται, τουναντίον, πως ο παράγοντας της σειράς μέσα στο παίγνιο μαζί με αυτόν του χρονικού περιορισμού γ (προθεσμία-deadline) είναι αποφασιστικής σημασίας.
description: This study deals with income taxation based on Greece’s economic system in a multi-agent, multi-issue environment. Every tax payer is considered a self interested automated agent who wants to pay to the government as little as possible but in the same time the required money for the state to run properly must be met. The total tax is based on the income of the tax payer and it is divided into tax intervals with different tax rate each. The purpose of this paper is to find a “fair” distribution of the tax rates given the tax intervals through negotiation of autonomous agents.
description: Σε συνεργασία με το τμήμα Λογιστικής και Χρηματοοικονομικής (Πανεπιστήμιο Μακεδονίας)
Propagation dynamics of abruptly autofocusing circular Airy-Gaussian vortex beams in the fractional Schrödinger equation
Creators: name: He, Shangling
name: Malomed, Boris A.
name: Mihalache, Dumitru
name: Peng, Xi
name: Yu, Xing
name: He, Yingji
name: Deng, Dongmei
Publisher: name: arXiv
Year: 2020
Subjects: subject: Pattern Formation and Solitons (nlin.PS)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: We introduce axisymmetric Airy-Gaussian vortex beams in a model of an optical system based on the (2+1)-dimensional fractional Schrödinger equation, characterized by its Lévy index (LI). By means of numerical methods, we explore propagation dynamics of the beams with vorticities from 0 to 4. The propagation leads to abrupt autofocusing, followed by its reversal (rebound from the center). It is shown that LI, the relative width of the Airy and Gaussian factors, and the vorticity determine properties of the autofocusing dynamics, including the focusing distance, radius of the focal light spot, and peak intensity at the focus. A maximum of the peak intensity is attained at intermediate values of LI, close to LI=1.4 . Dynamics of the abrupt autofocusing of Airy-Gaussian beams carrying vortex pairs (split double vortices) is considered too.
description: to be published in Chaos, Solitons & Fractals
Επίδραση μερικών παραγόντων στις συμβιωτικές σχέσεις της αμπέλου με μυκορριζικούς μύκητες
Creators: name: Ατσικπάσης, Παναγιώτης Σπύρου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: Μυκόρριζες
Αποικισμός
Αμπέλι
Mycorrhizas
Colonization
Vine

description: Σκοπός της παρούσης διατριβής ήταν η μελέτη της επίδρασης διαφόρων φυτοπροστατευτικών σκευασμάτων στους ενδομυκορριζικούς μύκητες των ριζών της αμπέλου. Για αυτό το σκοπό εφαρμόσαμε τέσσερα μυκήτοκτόνα (διασυστηματικά και μη) και ενα διασυστηματικό ζιζανιοκτόνο και ακολούθως εξετάσαμε μέσω της στατιστικής ανάλυσης την επίδραση αυτών στο ολικό ποσοστό αποικισμού των ριζών από τους ενδομυκορριζικούς μύκητες. Από την εφαρμογή των σκευασμάτων διαπιστώσαμε πως η συνδυαστική εφαρμογή δυο σκευασμάτων περιόρισε τα ποσοστά αποικισμού των ριζών. Επιπλέον εξετάσαμε την πιθανότητα συσχέτισης του ολικού ποσοστού αποικισμού με τον αριθμό των σπορίων του υποστρώμματος των επεμβάσεων. Διαπιστώσαμε την ύπαρξη μιας ισχυρά θετικής συσχέτισης ανάμεσα στις δυο παραπάνω μεταβλητές.
description: The aim of this thesis was to study the effect of different plant protection preparations on mycorrhizal fungi of the roots of the vine. For this purpose we applied four fungicides (systemic and non), and a systemic herbicide and then examined through statistical analysis of the effect of these on the total rate of colonization of the roots by mycorrhizal fungi. The application of the formulations found that the combined application of two formulations reduced the colonization rates of roots. In addition we examined the possibility of association between the overall rate of colonization of the number of spores of the substrates of interventions. We found that there is a strong positive correlation between the two variables above.
Tunnel-barrier-enhanced dc voltage signals induced by magnetization dynamics in magnetic tunnel junctions
Creators: name: Tserkovnyak, Yaroslav
name: Moriyama, T.
name: Xiao, John Q.
Publisher: name: arXiv
Year: 2008
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: We theoretically study the recently observed tunnel-barrier-enhanced dc voltage signals generated by magnetization precession in magnetic tunnel junctions. While the spin pumping is suppressed by the high tunneling impedance, two complimentary processes are predicted to result in a sizable voltage generation in ferromagnet (F)|insulator (I)|normal-metal (N) and F|I|F junctions, with one ferromagnet being resonantly excited. Magnetic dynamics in F|I|F systems induces a robust charge pumping, translating into voltage in open circuits. In addition, dynamics in a single ferromagnetic layer develops longitudinal spin accumulation inside the ferromagnet. A tunnel barrier then acts as a nonintrusive probe that converts the spin accumulation into a measurable voltage. Neither of the proposed mechanisms suffers from spin relaxation, which is typically fast on the scale of the exponentially slow tunneling rates. The longitudinal spin-accumulation buildup, however, is very sensitive to the phenomenological ingredients of the spin-relaxation picture.
description: 5 pages, 2 figures
Η κατάκτηση των αγηφηματικών ιστορικών εννοιών από τους Ελληνοκύπριους μαθητές της έκτης δημοτικού (11-12)
Creators: name: Σκούρος, Τρύφωνας
Publisher: name: Παιδαγωγική Επιθεώρηση
Year: 1999

description: Παιδαγωγική Επιθεώρηση, Vol. 29 (1999)
Direct Generation of Radially Polarized Vector Vortex Beam with an Exciton-Polariton Laser
Creators: name: Hu, Jiaqi
name: Kim, Seonghoon
name: Schneider, Christian
name: Höfling, Sven
name: Deng, Hui
Publisher: name: arXiv
Year: 2020
Subjects: subject: Optics (physics.optics)
subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: Vector vortex beams are a class of optical beams with singularities in their space-variant polarization. Vector vortex beam lasers have applications in many areas including imaging and communication, where vertical-cavity lasers emitting Gaussian beams have been most widely used so far. Generation of vector vortex beams from vertical-cavity lasers has required external control or modulation. Here, by utilizing a polarization-selective subwavelength grating as one of the reflectors in a vertical semiconductor microcavity, we design the spin textures of the polariton mode and demonstrate polariton lasing in a single-mode, radially polarized vector vortex beam. Polarization and phase distributions of the emission are characterized by polarization-resolved imaging and interferometry. This method of vector vortex laser beam generation allows low threshold power, stable single-mode operation, scalability, and on-chip integration, all of which are important for applications in imaging and communication.
Frequency Correlations of QPOs Based on a Disk Oscillation Model in Warped Disks
Creators: name: Kato, Shoji
Publisher: name: arXiv
Year: 2007
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: In previous papers we proposed a model that high-frequency quasi-periodic oscillations (QPOs) observed in black-hole and neutron-star X-ray binaries are disk oscillations (inertial-acoustic and/or g-mode oscillations) resonantly excited on warped disks. In this paper we examine whether time variations of the QPOs and their frequency correlations observed in neutron-star X-ray binaries can be accounted for by this disk-oscillation model. By assuming that a warp has a time-dependent precession, we can well describe observed frequency correlations among kHz QPOs and LF QPOs in a wide range of frequencies.
description: 10 pages, to be published in PASJ 59(2007), No.2
Pembuatan Karakter Animasi "Halo Saya Disabilitas" untuk Memperkuat Isu Disabilitas pada Sektor Pendidikan
Creators: name: Hadiprawiro, Yulianto
name: Susanti, Dewi Indah
name: Hidayati, Atiek Nur
name: Saptodewo, Febrianto
name: Dawami, Angga Kusuma
Publisher: name: Zenodo
Year: 2023

description: The issue of disability in the education sector still has not had much influence on changing the stigma towards Children with Special Needs (ABK) with disabilities in the education sector. Through the animated characters in the service "Hello I am disabled" it is an effort to understand the personal character of people with disabilities in the school education sector. This paper uses a descriptive-qualitative perspective on the process of creating animated characters for the animation "Hello I'm Disabled". The result of this paper is a process of dedication to the form of animated characters that have a strong identity in displaying visual constructions with depictions of disabilities.
Spontaneous symmetry breaking in free theories with boundary potentials
Creators: name: Procházka, Vladimír
name: Söderberg, Alexander
Publisher: name: arXiv
Year: 2020
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Patterns of symmetry breaking induced by potentials at the boundary of free $O(N)$ models in $d=3- ε$ dimensions are studied. We show that the spontaneous symmetry breaking in these theories leads to a boundary RG flow ending with $N - 1$ Neumann modes in the IR. The possibility of fluctuation-induced symmetry breaking is examined and we derive a general formula for computing one-loop effective potentials at the boundary. Using the $ε-$expansion we test these ideas in an $O(N)\oplus O(N)$ model with boundary interactions. We determine the RG flow diagram of this theory and find that it has an IR-stable critical point satisfying conformal boundary conditions. The leading correction to the effective potential is computed and we argue the existence of a phase boundary separating the region flowing to the symmetric fixed point from the region flowing to a symmetry-broken phase with a combination of Neumann and Dirchlet boundary conditions.
description: 17 pages, 3 figures + Mathematica notebook included
Περιοδεύοντες εκπαιδευτικοί: μια πρόκληση για την αγωγή των παιδιώ με ειδικές ανάγκες στην Ελλάδα
Creators: name: Κουτάντος, Δημήτρης
Publisher: name: Παιδαγωγική Επιθεώρηση
Year: 1999

description: During his studies for children with special educational needs in Great Britain the author come in touch with a new role -teacher for the Greek educational system: 'peripatetic' teacher. The aim of this paper is to describe and introduce this role in the Greek education. The researcher interviewed 11 peripatetic teachers with an average of professional experience 15 years, and worked for a short time alongside. The results of the study indicated the positive role of these teachers. These teachers seem to have an essential role for the education of children with special educational needs and the researcher-teacher evaluates that it is a positive challenge for the Greek educational system.
description: Παιδαγωγική Επιθεώρηση, Vol. 29 (1999)
Μελέτη της επίδρασης διαφορετικών μεγεθών δειγμάτων εκπαίδευσης στην αξιολόγηση τεχνικών εξόρυξης πληροφοριών από δορυφορικές εικόνες υψηλής χωρικής ανάλυσης αστικής περιοχής
Creators: name: Δήμου, Μαρία Νικολάου
Publisher: name: Aristotle University of Thessaloniki
Year: 2015
Subjects: μηχανική μάθηση
μηχανές υποστήριξης διανυσμάτων
μέθοδοι συνόλου
machine learning
support vector machines
ensemble methods

description: Σκοπός της διατριβής ήταν η εφαρμογή τεχνικών εξόρυξης πληροφοριών και η μελέτη της επίδρασης διαφορετικών μεγεθών δειγμάτων εκπαίδευσης στην εκτίμηση της ακρίβειας. Αρχικά έγινε μία ανασκόπηση της βιβλιογραφίας όσον αφορά της μεθόδους ταξινόμησης. Στην συνέχεια παρατίθεται η θεωρία των τεχνικών εξόρυξης πληροφοριών που χρησιμοποιήθηκαν, δηλαδή της μεθόδου «Μηχανή διανυσμάτων υποστήριξης» και της μεθόδου «Τυχαίο Δάσος» . Επιπλέον, αναλύεται η ανάπτυξη αυτών των μεθόδων και εφαρμόζονται στα διαθέσιμα δορυφορικά δεδομένα. Τέλος, πραγματοποιείται μια συνολική αξιολόγηση των μεθόδων και εξάγονται συμπεράσματα.
description: The aim of the present thesis was the application of mining information techniques and the investigation of the effect of different sizes training samples in accuracy assessment. At first we review the literature regarding the classification methods. Then we presented the theory of mining information techniques, namely the method "Support Vector Machine" and "Random Forest". In addition, we analyzed the development of these methods and we applied them in the available satellite data. Finally, we provide a comprehensive assessment of the methods and conclusions are drawn.